From bc0c3357601e3ff1b006600530079bd246ef0d82 Mon Sep 17 00:00:00 2001 From: Mateusz Guzik Date: Wed, 23 Aug 2023 19:05:56 +0200 Subject: mm: remove remnants of SPLIT_RSS_COUNTING The feature got retired in f1a7941243c1 ("mm: convert mm's rss stats into percpu_counter"), but the patch failed to fully clean it up. Link: https://lkml.kernel.org/r/20230823170556.2281747-1-mjguzik@gmail.com Signed-off-by: Mateusz Guzik Acked-by: Shakeel Butt Signed-off-by: Andrew Morton --- include/linux/mm.h | 8 -------- 1 file changed, 8 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index bf5d0b1b16f4..7613150acab9 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2628,14 +2628,6 @@ static inline void setmax_mm_hiwater_rss(unsigned long *maxrss, *maxrss = hiwater_rss; } -#if defined(SPLIT_RSS_COUNTING) -void sync_mm_rss(struct mm_struct *mm); -#else -static inline void sync_mm_rss(struct mm_struct *mm) -{ -} -#endif - #ifndef CONFIG_ARCH_HAS_PTE_SPECIAL static inline int pte_special(pte_t pte) { -- cgit v1.2.3 From 91e79d22be75fec88ae58d274a7c9e49d6215099 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Wed, 23 Aug 2023 00:13:14 +0100 Subject: mm: convert DAX lock/unlock page to lock/unlock folio The one caller of DAX lock/unlock page already calls compound_head(), so use page_folio() instead, then use a folio throughout the DAX code to remove uses of page->mapping and page->index. [jane.chu@oracle.com: add comment to mf_generic_kill_procss(), simplify mf_generic_kill_procs:folio initialization] Link: https://lkml.kernel.org/r/20230908222336.186313-1-jane.chu@oracle.com Link: https://lkml.kernel.org/r/20230822231314.349200-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Jane Chu Acked-by: Naoya Horiguchi Cc: Dan Williams Cc: Jane Chu Signed-off-by: Andrew Morton --- fs/dax.c | 24 ++++++++++++------------ include/linux/dax.h | 10 +++++----- mm/memory-failure.c | 29 ++++++++++++++++------------- 3 files changed, 33 insertions(+), 30 deletions(-) (limited to 'include/linux') diff --git a/fs/dax.c b/fs/dax.c index 8fafecbe42b1..3380b43cb6bb 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -412,23 +412,23 @@ static struct page *dax_busy_page(void *entry) return NULL; } -/* - * dax_lock_page - Lock the DAX entry corresponding to a page - * @page: The page whose entry we want to lock +/** + * dax_lock_folio - Lock the DAX entry corresponding to a folio + * @folio: The folio whose entry we want to lock * * Context: Process context. - * Return: A cookie to pass to dax_unlock_page() or 0 if the entry could + * Return: A cookie to pass to dax_unlock_folio() or 0 if the entry could * not be locked. */ -dax_entry_t dax_lock_page(struct page *page) +dax_entry_t dax_lock_folio(struct folio *folio) { XA_STATE(xas, NULL, 0); void *entry; - /* Ensure page->mapping isn't freed while we look at it */ + /* Ensure folio->mapping isn't freed while we look at it */ rcu_read_lock(); for (;;) { - struct address_space *mapping = READ_ONCE(page->mapping); + struct address_space *mapping = READ_ONCE(folio->mapping); entry = NULL; if (!mapping || !dax_mapping(mapping)) @@ -447,11 +447,11 @@ dax_entry_t dax_lock_page(struct page *page) xas.xa = &mapping->i_pages; xas_lock_irq(&xas); - if (mapping != page->mapping) { + if (mapping != folio->mapping) { xas_unlock_irq(&xas); continue; } - xas_set(&xas, page->index); + xas_set(&xas, folio->index); entry = xas_load(&xas); if (dax_is_locked(entry)) { rcu_read_unlock(); @@ -467,10 +467,10 @@ dax_entry_t dax_lock_page(struct page *page) return (dax_entry_t)entry; } -void dax_unlock_page(struct page *page, dax_entry_t cookie) +void dax_unlock_folio(struct folio *folio, dax_entry_t cookie) { - struct address_space *mapping = page->mapping; - XA_STATE(xas, &mapping->i_pages, page->index); + struct address_space *mapping = folio->mapping; + XA_STATE(xas, &mapping->i_pages, folio->index); if (S_ISCHR(mapping->host->i_mode)) return; diff --git a/include/linux/dax.h b/include/linux/dax.h index 22cd9902345d..b463502b16e1 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -159,8 +159,8 @@ int dax_writeback_mapping_range(struct address_space *mapping, struct page *dax_layout_busy_page(struct address_space *mapping); struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end); -dax_entry_t dax_lock_page(struct page *page); -void dax_unlock_page(struct page *page, dax_entry_t cookie); +dax_entry_t dax_lock_folio(struct folio *folio); +void dax_unlock_folio(struct folio *folio, dax_entry_t cookie); dax_entry_t dax_lock_mapping_entry(struct address_space *mapping, unsigned long index, struct page **page); void dax_unlock_mapping_entry(struct address_space *mapping, @@ -182,14 +182,14 @@ static inline int dax_writeback_mapping_range(struct address_space *mapping, return -EOPNOTSUPP; } -static inline dax_entry_t dax_lock_page(struct page *page) +static inline dax_entry_t dax_lock_folio(struct folio *folio) { - if (IS_DAX(page->mapping->host)) + if (IS_DAX(folio->mapping->host)) return ~0UL; return 0; } -static inline void dax_unlock_page(struct page *page, dax_entry_t cookie) +static inline void dax_unlock_folio(struct folio *folio, dax_entry_t cookie) { } diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 4d6e43c88489..660c21859118 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1713,20 +1713,23 @@ static void unmap_and_kill(struct list_head *to_kill, unsigned long pfn, kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags); } +/* + * Only dev_pagemap pages get here, such as fsdax when the filesystem + * either do not claim or fails to claim a hwpoison event, or devdax. + * The fsdax pages are initialized per base page, and the devdax pages + * could be initialized either as base pages, or as compound pages with + * vmemmap optimization enabled. Devdax is simplistic in its dealing with + * hwpoison, such that, if a subpage of a compound page is poisoned, + * simply mark the compound head page is by far sufficient. + */ static int mf_generic_kill_procs(unsigned long long pfn, int flags, struct dev_pagemap *pgmap) { - struct page *page = pfn_to_page(pfn); + struct folio *folio = pfn_folio(pfn); LIST_HEAD(to_kill); dax_entry_t cookie; int rc = 0; - /* - * Pages instantiated by device-dax (not filesystem-dax) - * may be compound pages. - */ - page = compound_head(page); - /* * Prevent the inode from being freed while we are interrogating * the address_space, typically this would be handled by @@ -1734,11 +1737,11 @@ static int mf_generic_kill_procs(unsigned long long pfn, int flags, * also prevents changes to the mapping of this pfn until * poison signaling is complete. */ - cookie = dax_lock_page(page); + cookie = dax_lock_folio(folio); if (!cookie) return -EBUSY; - if (hwpoison_filter(page)) { + if (hwpoison_filter(&folio->page)) { rc = -EOPNOTSUPP; goto unlock; } @@ -1760,7 +1763,7 @@ static int mf_generic_kill_procs(unsigned long long pfn, int flags, * Use this flag as an indication that the dax page has been * remapped UC to prevent speculative consumption of poison. */ - SetPageHWPoison(page); + SetPageHWPoison(&folio->page); /* * Unlike System-RAM there is no possibility to swap in a @@ -1769,11 +1772,11 @@ static int mf_generic_kill_procs(unsigned long long pfn, int flags, * SIGBUS (i.e. MF_MUST_KILL) */ flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; - collect_procs(page, &to_kill, true); + collect_procs(&folio->page, &to_kill, true); - unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags); + unmap_and_kill(&to_kill, pfn, folio->mapping, folio->index, flags); unlock: - dax_unlock_page(page, cookie); + dax_unlock_folio(folio, cookie); return rc; } -- cgit v1.2.3 From b1e5a3dee255a11cbdd5a0e814829276bd33a793 Mon Sep 17 00:00:00 2001 From: "Joel Fernandes (Google)" Date: Sun, 3 Sep 2023 15:13:23 +0000 Subject: mm/mremap: allow moves within the same VMA for stack moves For the stack move happening in shift_arg_pages(), the move is happening within the same VMA which spans the old and new ranges. In case the aligned address happens to fall within that VMA, allow such moves and don't abort the mremap alignment optimization. In the regular non-stack mremap case, we cannot allow any such moves as will end up destroying some part of the mapping (either the source of the move, or part of the existing mapping). So just avoid it for stack moves. Link: https://lkml.kernel.org/r/20230903151328.2981432-3-joel@joelfernandes.org Signed-off-by: Joel Fernandes (Google) Reviewed-by: Lorenzo Stoakes Cc: Kalesh Singh Cc: "Kirill A. Shutemov" Cc: Liam R. Howlett Cc: Linus Torvalds Cc: Lokesh Gidra Cc: Michal Hocko Cc: Paul E. McKenney Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- fs/exec.c | 2 +- include/linux/mm.h | 2 +- mm/mremap.c | 33 +++++++++++++++++++-------------- 3 files changed, 21 insertions(+), 16 deletions(-) (limited to 'include/linux') diff --git a/fs/exec.c b/fs/exec.c index eb039041ad6a..4aa19b24f281 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -713,7 +713,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) * process cleanup to remove whatever mess we made. */ if (length != move_page_tables(vma, old_start, - vma, new_start, length, false)) + vma, new_start, length, false, true)) return -ENOMEM; lru_add_drain(); diff --git a/include/linux/mm.h b/include/linux/mm.h index 7613150acab9..21c3d4e8a282 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2480,7 +2480,7 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen); extern unsigned long move_page_tables(struct vm_area_struct *vma, unsigned long old_addr, struct vm_area_struct *new_vma, unsigned long new_addr, unsigned long len, - bool need_rmap_locks); + bool need_rmap_locks, bool for_stack); /* * Flags used by change_protection(). For now we make it a bitmap so diff --git a/mm/mremap.c b/mm/mremap.c index e2b65a17148e..ce8a23ef325a 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -490,12 +490,13 @@ static bool move_pgt_entry(enum pgt_entry entry, struct vm_area_struct *vma, } /* - * A helper to check if a previous mapping exists. Required for - * move_page_tables() and realign_addr() to determine if a previous mapping - * exists before we can do realignment optimizations. + * A helper to check if aligning down is OK. The aligned address should fall + * on *no mapping*. For the stack moving down, that's a special move within + * the VMA that is created to span the source and destination of the move, + * so we make an exception for it. */ static bool can_align_down(struct vm_area_struct *vma, unsigned long addr_to_align, - unsigned long mask) + unsigned long mask, bool for_stack) { unsigned long addr_masked = addr_to_align & mask; @@ -504,9 +505,13 @@ static bool can_align_down(struct vm_area_struct *vma, unsigned long addr_to_ali * of the corresponding VMA, we can't align down or we will destroy part * of the current mapping. */ - if (vma->vm_start != addr_to_align) + if (!for_stack && vma->vm_start != addr_to_align) return false; + /* In the stack case we explicitly permit in-VMA alignment. */ + if (for_stack && addr_masked >= vma->vm_start) + return true; + /* * Make sure the realignment doesn't cause the address to fall on an * existing mapping. @@ -517,7 +522,7 @@ static bool can_align_down(struct vm_area_struct *vma, unsigned long addr_to_ali /* Opportunistically realign to specified boundary for faster copy. */ static void try_realign_addr(unsigned long *old_addr, struct vm_area_struct *old_vma, unsigned long *new_addr, struct vm_area_struct *new_vma, - unsigned long mask) + unsigned long mask, bool for_stack) { /* Skip if the addresses are already aligned. */ if ((*old_addr & ~mask) == 0) @@ -528,8 +533,8 @@ static void try_realign_addr(unsigned long *old_addr, struct vm_area_struct *old return; /* Ensure realignment doesn't cause overlap with existing mappings. */ - if (!can_align_down(old_vma, *old_addr, mask) || - !can_align_down(new_vma, *new_addr, mask)) + if (!can_align_down(old_vma, *old_addr, mask, for_stack) || + !can_align_down(new_vma, *new_addr, mask, for_stack)) return; *old_addr = *old_addr & mask; @@ -539,7 +544,7 @@ static void try_realign_addr(unsigned long *old_addr, struct vm_area_struct *old unsigned long move_page_tables(struct vm_area_struct *vma, unsigned long old_addr, struct vm_area_struct *new_vma, unsigned long new_addr, unsigned long len, - bool need_rmap_locks) + bool need_rmap_locks, bool for_stack) { unsigned long extent, old_end; struct mmu_notifier_range range; @@ -559,9 +564,9 @@ unsigned long move_page_tables(struct vm_area_struct *vma, * If possible, realign addresses to PMD boundary for faster copy. * Only realign if the mremap copying hits a PMD boundary. */ - if ((vma != new_vma) - && (len >= PMD_SIZE - (old_addr & ~PMD_MASK))) - try_realign_addr(&old_addr, vma, &new_addr, new_vma, PMD_MASK); + if (len >= PMD_SIZE - (old_addr & ~PMD_MASK)) + try_realign_addr(&old_addr, vma, &new_addr, new_vma, PMD_MASK, + for_stack); flush_cache_range(vma, old_addr, old_end); mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma->vm_mm, @@ -708,7 +713,7 @@ static unsigned long move_vma(struct vm_area_struct *vma, } moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len, - need_rmap_locks); + need_rmap_locks, false); if (moved_len < old_len) { err = -ENOMEM; } else if (vma->vm_ops && vma->vm_ops->mremap) { @@ -722,7 +727,7 @@ static unsigned long move_vma(struct vm_area_struct *vma, * and then proceed to unmap new area instead of old. */ move_page_tables(new_vma, new_addr, vma, old_addr, moved_len, - true); + true, false); vma = new_vma; old_len = new_len; old_addr = new_addr; -- cgit v1.2.3 From d896073fc767ebb40c11a6a9de71c390757ac64b Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Thu, 7 Sep 2023 02:29:27 +0000 Subject: mm/damon/core: add more comments for nr_accesses The comment on struct damon_region about nr_accesses field looks not sufficient. Many people actually used to ask what nr_accesses mean. There is more detailed explanation of the mechanism on the comment for struct damon_attrs, but it is also ambiguous, as it doesn't specify the name of the counter for aggregating the access check results. Make those more detailed. Link: https://lkml.kernel.org/r/20230907022929.91361-10-sj@kernel.org Signed-off-by: SeongJae Park Cc: Jonathan Corbet Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton --- include/linux/damon.h | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index ae2664d1d5f1..266f92b34dd2 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -43,6 +43,10 @@ struct damon_addr_range { * @list: List head for siblings. * @age: Age of this region. * + * @nr_accesses is reset to zero for every &damon_attrs->aggr_interval and be + * increased for every &damon_attrs->sample_interval if an access to the region + * during the last sampling interval is found. + * * @age is initially zero, increased for each aggregation interval, and reset * to zero again if the access frequency is significantly changed. If two * regions are merged into a new region, both @nr_accesses and @age of the new @@ -472,13 +476,14 @@ struct damon_callback { * regions. * * For each @sample_interval, DAMON checks whether each region is accessed or - * not. It aggregates and keeps the access information (number of accesses to - * each region) for @aggr_interval time. DAMON also checks whether the target - * memory regions need update (e.g., by ``mmap()`` calls from the application, - * in case of virtual memory monitoring) and applies the changes for each - * @ops_update_interval. All time intervals are in micro-seconds. - * Please refer to &struct damon_operations and &struct damon_callback for more - * detail. + * not during the last @sample_interval. If such access is found, DAMON + * aggregates the information by increasing &damon_region->nr_accesses for + * @aggr_interval time. For each @aggr_interval, the count is reset. DAMON + * also checks whether the target memory regions need update (e.g., by + * ``mmap()`` calls from the application, in case of virtual memory monitoring) + * and applies the changes for each @ops_update_interval. All time intervals + * are in micro-seconds. Please refer to &struct damon_operations and &struct + * damon_callback for more detail. */ struct damon_attrs { unsigned long sample_interval; -- cgit v1.2.3 From cf0a96bd3ab4d9d8a1c92baf1a822f2ddbca3a34 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Thu, 7 Sep 2023 02:29:28 +0000 Subject: mm/damon/core: remove duplicated comment for watermarks-based deactivation The comment for explaining about watermarks-based monitoring part deactivation is duplicated in two paragraphs. Remove one. Link: https://lkml.kernel.org/r/20230907022929.91361-11-sj@kernel.org Signed-off-by: SeongJae Park Cc: Jonathan Corbet Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton --- include/linux/damon.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index 266f92b34dd2..ab3089de1478 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -317,9 +317,6 @@ struct damos_access_pattern { * monitoring context are inactive, DAMON stops monitoring either, and just * repeatedly checks the watermarks. * - * If all schemes that registered to a &struct damon_ctx are inactive, DAMON - * stops monitoring and just repeatedly checks the watermarks. - * * Before applying the &action to a memory region, &struct damon_operations * implementation could check pages of the region and skip &action to respect * &filters -- cgit v1.2.3 From 7cd34dd3c9bf1d67ce7d1ab3fe8886c583ae0d9a Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Mon, 11 Sep 2023 14:21:13 +0300 Subject: efi/unaccepted: do not let /proc/vmcore try to access unaccepted memory Patch series "Do not try to access unaccepted memory", v2. Support for unaccepted memory was added recently, refer commit dcdfdd40fa82 ("mm: Add support for unaccepted memory"), whereby a virtual machine may need to accept memory before it can be used. Plug a few gaps where RAM is exposed without checking if it is unaccepted memory. This patch (of 2): Support for unaccepted memory was added recently, refer commit dcdfdd40fa82 ("mm: Add support for unaccepted memory"), whereby a virtual machine may need to accept memory before it can be used. Do not let /proc/vmcore try to access unaccepted memory because it can cause the guest to fail. For /proc/vmcore, which is read-only, this means a read or mmap of unaccepted memory will return zeros. Link: https://lkml.kernel.org/r/20230911112114.91323-1-adrian.hunter@intel.com Link: https://lkml.kernel.org/r/20230911112114.91323-2-adrian.hunter@intel.com Signed-off-by: Adrian Hunter Cc: Ard Biesheuvel Cc: Baoquan He Cc: Borislav Petkov (AMD) Cc: Dave Hansen Cc: Dave Young Cc: Kirill A. Shutemov Cc: Lorenzo Stoakes Cc: Mike Rapoport Cc: Tom Lendacky Cc: Vivek Goyal Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- drivers/firmware/efi/unaccepted_memory.c | 20 ++++++++++++++++++++ include/linux/mm.h | 7 +++++++ 2 files changed, 27 insertions(+) (limited to 'include/linux') diff --git a/drivers/firmware/efi/unaccepted_memory.c b/drivers/firmware/efi/unaccepted_memory.c index 853f7dc3c21d..79ba576b22e3 100644 --- a/drivers/firmware/efi/unaccepted_memory.c +++ b/drivers/firmware/efi/unaccepted_memory.c @@ -3,6 +3,7 @@ #include #include #include +#include #include /* Protects unaccepted memory bitmap */ @@ -145,3 +146,22 @@ bool range_contains_unaccepted_memory(phys_addr_t start, phys_addr_t end) return ret; } + +#ifdef CONFIG_PROC_VMCORE +static bool unaccepted_memory_vmcore_pfn_is_ram(struct vmcore_cb *cb, + unsigned long pfn) +{ + return !pfn_is_unaccepted_memory(pfn); +} + +static struct vmcore_cb vmcore_cb = { + .pfn_is_ram = unaccepted_memory_vmcore_pfn_is_ram, +}; + +static int __init unaccepted_memory_init_kdump(void) +{ + register_vmcore_cb(&vmcore_cb); + return 0; +} +core_initcall(unaccepted_memory_init_kdump); +#endif /* CONFIG_PROC_VMCORE */ diff --git a/include/linux/mm.h b/include/linux/mm.h index 21c3d4e8a282..31dc25d3f6b5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4054,4 +4054,11 @@ static inline void accept_memory(phys_addr_t start, phys_addr_t end) #endif +static inline bool pfn_is_unaccepted_memory(unsigned long pfn) +{ + phys_addr_t paddr = pfn << PAGE_SHIFT; + + return range_contains_unaccepted_memory(paddr, paddr + PAGE_SIZE); +} + #endif /* _LINUX_MM_H */ -- cgit v1.2.3 From 3ee0aa9f06756e959633ffda37856c6741d948ed Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:25:14 +0800 Subject: mm: move some shrinker-related function declarations to mm/internal.h MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Patch series "cleanups for lockless slab shrink", v4. This series is some cleanups for lockless slab shrink. This patch (of 4): The following functions are only used inside the mm subsystem, so it's better to move their declarations to the mm/internal.h file. 1. shrinker_debugfs_add() 2. shrinker_debugfs_detach() 3. shrinker_debugfs_remove() Link: https://lkml.kernel.org/r/20230911092517.64141-1-zhengqi.arch@bytedance.com Link: https://lkml.kernel.org/r/20230911092517.64141-2-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Cc: Christian Brauner Cc: Christian König Cc: Chuck Lever Cc: Daniel Vetter Cc: Darrick J. Wong Cc: Dave Chinner Cc: Greg Kroah-Hartman Cc: Joel Fernandes Cc: Kirill Tkhai Cc: Paul E. McKenney Cc: Roman Gushchin Cc: Sergey Senozhatsky Cc: Steven Price Cc: Theodore Ts'o Cc: Vlastimil Babka Cc: Daniel Vetter Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Coly Li Cc: Dai Ngo Cc: Dave Hansen Cc: David Airlie Cc: David Hildenbrand Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Sean Paul Cc: Song Liu Cc: Stefano Stabellini Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- include/linux/shrinker.h | 19 ------------------- mm/internal.h | 26 ++++++++++++++++++++++++++ mm/shrinker_debug.c | 2 ++ 3 files changed, 28 insertions(+), 19 deletions(-) (limited to 'include/linux') diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 224293b2dd06..8dc15aa37410 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -106,28 +106,9 @@ extern void free_prealloced_shrinker(struct shrinker *shrinker); extern void synchronize_shrinkers(void); #ifdef CONFIG_SHRINKER_DEBUG -extern int shrinker_debugfs_add(struct shrinker *shrinker); -extern struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker, - int *debugfs_id); -extern void shrinker_debugfs_remove(struct dentry *debugfs_entry, - int debugfs_id); extern int __printf(2, 3) shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...); #else /* CONFIG_SHRINKER_DEBUG */ -static inline int shrinker_debugfs_add(struct shrinker *shrinker) -{ - return 0; -} -static inline struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker, - int *debugfs_id) -{ - *debugfs_id = -1; - return NULL; -} -static inline void shrinker_debugfs_remove(struct dentry *debugfs_entry, - int debugfs_id) -{ -} static inline __printf(2, 3) int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) { diff --git a/mm/internal.h b/mm/internal.h index 30cf724ddbce..939d1227a527 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1154,4 +1154,30 @@ struct vma_prepare { struct vm_area_struct *remove; struct vm_area_struct *remove2; }; + +/* shrinker related functions */ + +#ifdef CONFIG_SHRINKER_DEBUG +extern int shrinker_debugfs_add(struct shrinker *shrinker); +extern struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker, + int *debugfs_id); +extern void shrinker_debugfs_remove(struct dentry *debugfs_entry, + int debugfs_id); +#else /* CONFIG_SHRINKER_DEBUG */ +static inline int shrinker_debugfs_add(struct shrinker *shrinker) +{ + return 0; +} +static inline struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker, + int *debugfs_id) +{ + *debugfs_id = -1; + return NULL; +} +static inline void shrinker_debugfs_remove(struct dentry *debugfs_entry, + int debugfs_id) +{ +} +#endif /* CONFIG_SHRINKER_DEBUG */ + #endif /* __MM_INTERNAL_H */ diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c index 3ab53fad8876..ee0cddb4530f 100644 --- a/mm/shrinker_debug.c +++ b/mm/shrinker_debug.c @@ -6,6 +6,8 @@ #include #include +#include "internal.h" + /* defined in vmscan.c */ extern struct rw_semaphore shrinker_rwsem; extern struct list_head shrinker_list; -- cgit v1.2.3 From 0b2f5ea1aa39c0ed34bdadb53faf519e3d84ac4a Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:25:17 +0800 Subject: drm/ttm: introduce pool_shrink_rwsem MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, synchronize_shrinkers() is only used by TTM pool. It only requires that no shrinkers run in parallel. After we use RCU+refcount method to implement the lockless slab shrink, we can not use shrinker_rwsem or synchronize_rcu() to guarantee that all shrinker invocations have seen an update before freeing memory. So we introduce a new pool_shrink_rwsem to implement a private ttm_pool_synchronize_shrinkers(), so as to achieve the same purpose. Link: https://lkml.kernel.org/r/20230911092517.64141-5-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Reviewed-by: Christian König Acked-by: Daniel Vetter Cc: Christian Brauner Cc: Chuck Lever Cc: Daniel Vetter Cc: Darrick J. Wong Cc: Dave Chinner Cc: Greg Kroah-Hartman Cc: Joel Fernandes Cc: Kirill Tkhai Cc: Paul E. McKenney Cc: Roman Gushchin Cc: Sergey Senozhatsky Cc: Steven Price Cc: Theodore Ts'o Cc: Vlastimil Babka Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Coly Li Cc: Dai Ngo Cc: Dave Hansen Cc: David Airlie Cc: David Hildenbrand Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Sean Paul Cc: Song Liu Cc: Stefano Stabellini Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- drivers/gpu/drm/ttm/ttm_pool.c | 17 ++++++++++++++++- include/linux/shrinker.h | 1 - mm/shrinker.c | 15 --------------- 3 files changed, 16 insertions(+), 17 deletions(-) (limited to 'include/linux') diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c index cddb9151d20f..648ca70403a7 100644 --- a/drivers/gpu/drm/ttm/ttm_pool.c +++ b/drivers/gpu/drm/ttm/ttm_pool.c @@ -74,6 +74,7 @@ static struct ttm_pool_type global_dma32_uncached[MAX_ORDER + 1]; static spinlock_t shrinker_lock; static struct list_head shrinker_list; static struct shrinker mm_shrinker; +static DECLARE_RWSEM(pool_shrink_rwsem); /* Allocate pages of size 1 << order with the given gfp_flags */ static struct page *ttm_pool_alloc_page(struct ttm_pool *pool, gfp_t gfp_flags, @@ -317,6 +318,7 @@ static unsigned int ttm_pool_shrink(void) unsigned int num_pages; struct page *p; + down_read(&pool_shrink_rwsem); spin_lock(&shrinker_lock); pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list); list_move_tail(&pt->shrinker_list, &shrinker_list); @@ -329,6 +331,7 @@ static unsigned int ttm_pool_shrink(void) } else { num_pages = 0; } + up_read(&pool_shrink_rwsem); return num_pages; } @@ -572,6 +575,18 @@ void ttm_pool_init(struct ttm_pool *pool, struct device *dev, } EXPORT_SYMBOL(ttm_pool_init); +/** + * ttm_pool_synchronize_shrinkers - Wait for all running shrinkers to complete. + * + * This is useful to guarantee that all shrinker invocations have seen an + * update, before freeing memory, similar to rcu. + */ +static void ttm_pool_synchronize_shrinkers(void) +{ + down_write(&pool_shrink_rwsem); + up_write(&pool_shrink_rwsem); +} + /** * ttm_pool_fini - Cleanup a pool * @@ -593,7 +608,7 @@ void ttm_pool_fini(struct ttm_pool *pool) /* We removed the pool types from the LRU, but we need to also make sure * that no shrinker is concurrently freeing pages from the pool. */ - synchronize_shrinkers(); + ttm_pool_synchronize_shrinkers(); } EXPORT_SYMBOL(ttm_pool_fini); diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 8dc15aa37410..6b5843c3b827 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -103,7 +103,6 @@ extern int __printf(2, 3) register_shrinker(struct shrinker *shrinker, const char *fmt, ...); extern void unregister_shrinker(struct shrinker *shrinker); extern void free_prealloced_shrinker(struct shrinker *shrinker); -extern void synchronize_shrinkers(void); #ifdef CONFIG_SHRINKER_DEBUG extern int __printf(2, 3) shrinker_debugfs_rename(struct shrinker *shrinker, diff --git a/mm/shrinker.c b/mm/shrinker.c index 043c87ccfab4..a16cd448b924 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -692,18 +692,3 @@ void unregister_shrinker(struct shrinker *shrinker) shrinker->nr_deferred = NULL; } EXPORT_SYMBOL(unregister_shrinker); - -/** - * synchronize_shrinkers - Wait for all running shrinkers to complete. - * - * This is equivalent to calling unregister_shrink() and register_shrinker(), - * but atomically and with less overhead. This is useful to guarantee that all - * shrinker invocations have seen an update, before freeing memory, similar to - * rcu. - */ -void synchronize_shrinkers(void) -{ - down_write(&shrinker_rwsem); - up_write(&shrinker_rwsem); -} -EXPORT_SYMBOL(synchronize_shrinkers); -- cgit v1.2.3 From c42d50aefd17a6bad3ed617769edbbb579137545 Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:44:00 +0800 Subject: mm: shrinker: add infrastructure for dynamically allocating shrinker Patch series "use refcount+RCU method to implement lockless slab shrink", v6. 1. Background ============= We used to implement the lockless slab shrink with SRCU [1], but then kernel test robot reported -88.8% regression in stress-ng.ramfs.ops_per_sec test case [2], so we reverted it [3]. This patch series aims to re-implement the lockless slab shrink using the refcount+RCU method proposed by Dave Chinner [4]. [1]. https://lore.kernel.org/lkml/20230313112819.38938-1-zhengqi.arch@bytedance.com/ [2]. https://lore.kernel.org/lkml/202305230837.db2c233f-yujie.liu@intel.com/ [3]. https://lore.kernel.org/all/20230609081518.3039120-1-qi.zheng@linux.dev/ [4]. https://lore.kernel.org/lkml/ZIJhou1d55d4H1s0@dread.disaster.area/ 2. Implementation ================= Currently, the shrinker instances can be divided into the following three types: a) global shrinker instance statically defined in the kernel, such as workingset_shadow_shrinker. b) global shrinker instance statically defined in the kernel modules, such as mmu_shrinker in x86. c) shrinker instance embedded in other structures. For case a, the memory of shrinker instance is never freed. For case b, the memory of shrinker instance will be freed after synchronize_rcu() when the module is unloaded. For case c, the memory of shrinker instance will be freed along with the structure it is embedded in. In preparation for implementing lockless slab shrink, we need to dynamically allocate those shrinker instances in case c, then the memory can be dynamically freed alone by calling kfree_rcu(). This patchset adds the following new APIs for dynamically allocating shrinker, and add a private_data field to struct shrinker to record and get the original embedded structure. 1. shrinker_alloc() 2. shrinker_register() 3. shrinker_free() In order to simplify shrinker-related APIs and make shrinker more independent of other kernel mechanisms, this patchset uses the above APIs to convert all shrinkers (including case a and b) to dynamically allocated, and then remove all existing APIs. This will also have another advantage mentioned by Dave Chinner: ``` The other advantage of this is that it will break all the existing out of tree code and third party modules using the old API and will no longer work with a kernel using lockless slab shrinkers. They need to break (both at the source and binary levels) to stop bad things from happening due to using uncoverted shrinkers in the new setup. ``` Then we free the shrinker by calling call_rcu(), and use rcu_read_{lock,unlock}() to ensure that the shrinker instance is valid. And the shrinker::refcount mechanism ensures that the shrinker instance will not be run again after unregistration. So the structure that records the pointer of shrinker instance can be safely freed without waiting for the RCU read-side critical section. In this way, while we implement the lockless slab shrink, we don't need to be blocked in unregister_shrinker() to wait RCU read-side critical section. PATCH 1: introduce new APIs PATCH 2~38: convert all shrinnkers to use new APIs PATCH 39: remove old APIs PATCH 40~41: some cleanups and preparations PATCH 42-43: implement the lockless slab shrink PATCH 44~45: convert shrinker_rwsem to mutex 3. Testing ========== 3.1 slab shrink stress test --------------------------- We can reproduce the down_read_trylock() hotspot through the following script: ``` DIR="/root/shrinker/memcg/mnt" do_create() { mkdir -p /sys/fs/cgroup/memory/test echo 4G > /sys/fs/cgroup/memory/test/memory.limit_in_bytes for i in `seq 0 $1`; do mkdir -p /sys/fs/cgroup/memory/test/$i; echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs; mkdir -p $DIR/$i; done } do_mount() { for i in `seq $1 $2`; do mount -t tmpfs $i $DIR/$i; done } do_touch() { for i in `seq $1 $2`; do echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs; dd if=/dev/zero of=$DIR/$i/file$i bs=1M count=1 & done } case "$1" in touch) do_touch $2 $3 ;; test) do_create 4000 do_mount 0 4000 do_touch 0 3000 ;; *) exit 1 ;; esac ``` Save the above script, then run test and touch commands. Then we can use the following perf command to view hotspots: perf top -U -F 999 1) Before applying this patchset: 33.15% [kernel] [k] down_read_trylock 25.38% [kernel] [k] shrink_slab 21.75% [kernel] [k] up_read 4.45% [kernel] [k] _find_next_bit 2.27% [kernel] [k] do_shrink_slab 1.80% [kernel] [k] intel_idle_irq 1.79% [kernel] [k] shrink_lruvec 0.67% [kernel] [k] xas_descend 0.41% [kernel] [k] mem_cgroup_iter 0.40% [kernel] [k] shrink_node 0.38% [kernel] [k] list_lru_count_one 2) After applying this patchset: 64.56% [kernel] [k] shrink_slab 12.18% [kernel] [k] do_shrink_slab 3.30% [kernel] [k] __rcu_read_unlock 2.61% [kernel] [k] shrink_lruvec 2.49% [kernel] [k] __rcu_read_lock 1.93% [kernel] [k] intel_idle_irq 0.89% [kernel] [k] shrink_node 0.81% [kernel] [k] mem_cgroup_iter 0.77% [kernel] [k] mem_cgroup_calculate_protection 0.66% [kernel] [k] list_lru_count_one We can see that the first perf hotspot becomes shrink_slab, which is what we expect. 3.2 registration and unregistration stress test ----------------------------------------------- Run the command below to test: stress-ng --timeout 60 --times --verify --metrics-brief --ramfs 9 & 1) Before applying this patchset: setting to a 60 second run per stressor dispatching hogs: 9 ramfs stressor bogo ops real time usr time sys time bogo ops/s bogo ops/s (secs) (secs) (secs) (real time) (usr+sys time) ramfs 473062 60.00 8.00 279.13 7884.12 1647.59 for a 60.01s run time: 1440.34s available CPU time 7.99s user time ( 0.55%) 279.13s system time ( 19.38%) 287.12s total time ( 19.93%) load average: 7.12 2.99 1.15 successful run completed in 60.01s (1 min, 0.01 secs) 2) After applying this patchset: setting to a 60 second run per stressor dispatching hogs: 9 ramfs stressor bogo ops real time usr time sys time bogo ops/s bogo ops/s (secs) (secs) (secs) (real time) (usr+sys time) ramfs 477165 60.00 8.13 281.34 7952.55 1648.40 for a 60.01s run time: 1440.33s available CPU time 8.12s user time ( 0.56%) 281.34s system time ( 19.53%) 289.46s total time ( 20.10%) load average: 6.98 3.03 1.19 successful run completed in 60.01s (1 min, 0.01 secs) We can see that the ops/s has hardly changed. This patch (of 45): Currently, the shrinker instances can be divided into the following three types: a) global shrinker instance statically defined in the kernel, such as workingset_shadow_shrinker. b) global shrinker instance statically defined in the kernel modules, such as mmu_shrinker in x86. c) shrinker instance embedded in other structures. For case a, the memory of shrinker instance is never freed. For case b, the memory of shrinker instance will be freed after synchronize_rcu() when the module is unloaded. For case c, the memory of shrinker instance will be freed along with the structure it is embedded in. In preparation for implementing lockless slab shrink, we need to dynamically allocate those shrinker instances in case c, then the memory can be dynamically freed alone by calling kfree_rcu(). So this commit adds the following new APIs for dynamically allocating shrinker, and add a private_data field to struct shrinker to record and get the original embedded structure. 1. shrinker_alloc() Used to allocate shrinker instance itself and related memory, it will return a pointer to the shrinker instance on success and NULL on failure. 2. shrinker_register() Used to register the shrinker instance, which is same as the current register_shrinker_prepared(). 3. shrinker_free() Used to unregister (if needed) and free the shrinker instance. In order to simplify shrinker-related APIs and make shrinker more independent of other kernel mechanisms, subsequent submissions will use the above API to convert all shrinkers (including case a and b) to dynamically allocated, and then remove all existing APIs. This will also have another advantage mentioned by Dave Chinner: ``` The other advantage of this is that it will break all the existing out of tree code and third party modules using the old API and will no longer work with a kernel using lockless slab shrinkers. They need to break (both at the source and binary levels) to stop bad things from happening due to using unconverted shrinkers in the new setup. ``` [zhengqi.arch@bytedance.com: mm: shrinker: some cleanup] Link: https://lkml.kernel.org/r/20230919024607.65463-1-zhengqi.arch@bytedance.com Link: https://lkml.kernel.org/r/20230911094444.68966-1-zhengqi.arch@bytedance.com Link: https://lkml.kernel.org/r/20230911094444.68966-2-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Cc: Christian Brauner Cc: Chuck Lever Cc: Darrick J. Wong Cc: Dave Chinner Cc: Greg Kroah-Hartman Cc: Kirill Tkhai Cc: Paul E. McKenney Cc: Roman Gushchin Cc: Sergey Senozhatsky Cc: Steven Price Cc: Theodore Ts'o Cc: Vlastimil Babka Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Christian Koenig Cc: Coly Li Cc: Dai Ngo Cc: Daniel Vetter Cc: Daniel Vetter Cc: Dave Hansen Cc: David Airlie Cc: David Hildenbrand Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joel Fernandes (Google) Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Sean Paul Cc: Song Liu Cc: Stefano Stabellini Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- include/linux/shrinker.h | 19 ++++++--- mm/internal.h | 22 ++++++++++ mm/shrinker.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++ mm/shrinker_debug.c | 3 -- 4 files changed, 142 insertions(+), 8 deletions(-) (limited to 'include/linux') diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 6b5843c3b827..f4a5249f00b2 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -70,6 +70,8 @@ struct shrinker { int seeks; /* seeks to recreate an obj */ unsigned flags; + void *private_data; + /* These are for internal use */ struct list_head list; #ifdef CONFIG_MEMCG @@ -86,15 +88,22 @@ struct shrinker { }; #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */ -/* Flags */ -#define SHRINKER_REGISTERED (1 << 0) -#define SHRINKER_NUMA_AWARE (1 << 1) -#define SHRINKER_MEMCG_AWARE (1 << 2) +/* Internal flags */ +#define SHRINKER_REGISTERED BIT(0) +#define SHRINKER_ALLOCATED BIT(1) + +/* Flags for users to use */ +#define SHRINKER_NUMA_AWARE BIT(2) +#define SHRINKER_MEMCG_AWARE BIT(3) /* * It just makes sense when the shrinker is also MEMCG_AWARE for now, * non-MEMCG_AWARE shrinker should not have this flag set. */ -#define SHRINKER_NONSLAB (1 << 3) +#define SHRINKER_NONSLAB BIT(4) + +struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...); +void shrinker_register(struct shrinker *shrinker); +void shrinker_free(struct shrinker *shrinker); extern int __printf(2, 3) prealloc_shrinker(struct shrinker *shrinker, const char *fmt, ...); diff --git a/mm/internal.h b/mm/internal.h index 0471d6326d01..a273f4d948d8 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1160,6 +1160,20 @@ unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg, int priority); #ifdef CONFIG_SHRINKER_DEBUG +static inline int shrinker_debugfs_name_alloc(struct shrinker *shrinker, + const char *fmt, va_list ap) +{ + shrinker->name = kvasprintf_const(GFP_KERNEL, fmt, ap); + + return shrinker->name ? 0 : -ENOMEM; +} + +static inline void shrinker_debugfs_name_free(struct shrinker *shrinker) +{ + kfree_const(shrinker->name); + shrinker->name = NULL; +} + extern int shrinker_debugfs_add(struct shrinker *shrinker); extern struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker, int *debugfs_id); @@ -1170,6 +1184,14 @@ static inline int shrinker_debugfs_add(struct shrinker *shrinker) { return 0; } +static inline int shrinker_debugfs_name_alloc(struct shrinker *shrinker, + const char *fmt, va_list ap) +{ + return 0; +} +static inline void shrinker_debugfs_name_free(struct shrinker *shrinker) +{ +} static inline struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker, int *debugfs_id) { diff --git a/mm/shrinker.c b/mm/shrinker.c index a16cd448b924..d1032a4d5684 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -550,6 +550,112 @@ out: return freed; } +struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...) +{ + struct shrinker *shrinker; + unsigned int size; + va_list ap; + int err; + + shrinker = kzalloc(sizeof(struct shrinker), GFP_KERNEL); + if (!shrinker) + return NULL; + + va_start(ap, fmt); + err = shrinker_debugfs_name_alloc(shrinker, fmt, ap); + va_end(ap); + if (err) + goto err_name; + + shrinker->flags = flags | SHRINKER_ALLOCATED; + shrinker->seeks = DEFAULT_SEEKS; + + if (flags & SHRINKER_MEMCG_AWARE) { + err = prealloc_memcg_shrinker(shrinker); + if (err == -ENOSYS) { + /* Memcg is not supported, fallback to non-memcg-aware shrinker. */ + shrinker->flags &= ~SHRINKER_MEMCG_AWARE; + goto non_memcg; + } + + if (err) + goto err_flags; + + return shrinker; + } + +non_memcg: + /* + * The nr_deferred is available on per memcg level for memcg aware + * shrinkers, so only allocate nr_deferred in the following cases: + * - non-memcg-aware shrinkers + * - !CONFIG_MEMCG + * - memcg is disabled by kernel command line + */ + size = sizeof(*shrinker->nr_deferred); + if (flags & SHRINKER_NUMA_AWARE) + size *= nr_node_ids; + + shrinker->nr_deferred = kzalloc(size, GFP_KERNEL); + if (!shrinker->nr_deferred) + goto err_flags; + + return shrinker; + +err_flags: + shrinker_debugfs_name_free(shrinker); +err_name: + kfree(shrinker); + return NULL; +} +EXPORT_SYMBOL_GPL(shrinker_alloc); + +void shrinker_register(struct shrinker *shrinker) +{ + if (unlikely(!(shrinker->flags & SHRINKER_ALLOCATED))) { + pr_warn("Must use shrinker_alloc() to dynamically allocate the shrinker"); + return; + } + + down_write(&shrinker_rwsem); + list_add_tail(&shrinker->list, &shrinker_list); + shrinker->flags |= SHRINKER_REGISTERED; + shrinker_debugfs_add(shrinker); + up_write(&shrinker_rwsem); +} +EXPORT_SYMBOL_GPL(shrinker_register); + +void shrinker_free(struct shrinker *shrinker) +{ + struct dentry *debugfs_entry = NULL; + int debugfs_id; + + if (!shrinker) + return; + + down_write(&shrinker_rwsem); + if (shrinker->flags & SHRINKER_REGISTERED) { + list_del(&shrinker->list); + debugfs_entry = shrinker_debugfs_detach(shrinker, &debugfs_id); + shrinker->flags &= ~SHRINKER_REGISTERED; + } + + shrinker_debugfs_name_free(shrinker); + + if (shrinker->flags & SHRINKER_MEMCG_AWARE) + unregister_memcg_shrinker(shrinker); + up_write(&shrinker_rwsem); + + if (debugfs_entry) + shrinker_debugfs_remove(debugfs_entry, debugfs_id); + + kfree(shrinker->nr_deferred); + shrinker->nr_deferred = NULL; + + kfree(shrinker); +} +EXPORT_SYMBOL_GPL(shrinker_free); + /* * Add a shrinker callback to be called from the vm. */ diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c index e4ce509f619e..24aebe7c24cc 100644 --- a/mm/shrinker_debug.c +++ b/mm/shrinker_debug.c @@ -241,9 +241,6 @@ struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker, lockdep_assert_held(&shrinker_rwsem); - kfree_const(shrinker->name); - shrinker->name = NULL; - *debugfs_id = entry ? shrinker->debugfs_id : -1; shrinker->debugfs_entry = NULL; -- cgit v1.2.3 From 4b403dfa8ea8dfbc9d317b25a0433c1ac6765f7f Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:44:30 +0800 Subject: jbd2,ext4: dynamically allocate the jbd2-journal shrinker In preparation for implementing lockless slab shrink, use new APIs to dynamically allocate the jbd2-journal shrinker, so that it can be freed asynchronously via RCU. Then it doesn't need to wait for RCU read-side critical section when releasing the struct journal_s. Link: https://lkml.kernel.org/r/20230911094444.68966-32-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Acked-by: Jan Kara Cc: "Theodore Ts'o" Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Christian Brauner Cc: Christian Koenig Cc: Chuck Lever Cc: Coly Li Cc: Dai Ngo Cc: Daniel Vetter Cc: Daniel Vetter Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: Dave Hansen Cc: David Airlie Cc: David Hildenbrand Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Greg Kroah-Hartman Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joel Fernandes (Google) Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Kirill Tkhai Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Paul E. McKenney Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Roman Gushchin Cc: Sean Paul Cc: Sergey Senozhatsky Cc: Song Liu Cc: Stefano Stabellini Cc: Steven Price Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- fs/jbd2/journal.c | 29 ++++++++++++++++++----------- include/linux/jbd2.h | 2 +- 2 files changed, 19 insertions(+), 12 deletions(-) (limited to 'include/linux') diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 30dec2bd2ecc..ed53188472f9 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -1290,7 +1290,7 @@ static int jbd2_min_tag_size(void) static unsigned long jbd2_journal_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) { - journal_t *journal = container_of(shrink, journal_t, j_shrinker); + journal_t *journal = shrink->private_data; unsigned long nr_to_scan = sc->nr_to_scan; unsigned long nr_shrunk; unsigned long count; @@ -1316,7 +1316,7 @@ static unsigned long jbd2_journal_shrink_scan(struct shrinker *shrink, static unsigned long jbd2_journal_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { - journal_t *journal = container_of(shrink, journal_t, j_shrinker); + journal_t *journal = shrink->private_data; unsigned long count; count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count); @@ -1588,14 +1588,21 @@ static journal_t *journal_init_common(struct block_device *bdev, goto err_cleanup; journal->j_shrink_transaction = NULL; - journal->j_shrinker.scan_objects = jbd2_journal_shrink_scan; - journal->j_shrinker.count_objects = jbd2_journal_shrink_count; - journal->j_shrinker.seeks = DEFAULT_SEEKS; - journal->j_shrinker.batch = journal->j_max_transaction_buffers; - err = register_shrinker(&journal->j_shrinker, "jbd2-journal:(%u:%u)", - MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev)); - if (err) + + journal->j_shrinker = shrinker_alloc(0, "jbd2-journal:(%u:%u)", + MAJOR(bdev->bd_dev), + MINOR(bdev->bd_dev)); + if (!journal->j_shrinker) { + err = -ENOMEM; goto err_cleanup; + } + + journal->j_shrinker->scan_objects = jbd2_journal_shrink_scan; + journal->j_shrinker->count_objects = jbd2_journal_shrink_count; + journal->j_shrinker->batch = journal->j_max_transaction_buffers; + journal->j_shrinker->private_data = journal; + + shrinker_register(journal->j_shrinker); return journal; @@ -2172,9 +2179,9 @@ int jbd2_journal_destroy(journal_t *journal) brelse(journal->j_sb_buffer); } - if (journal->j_shrinker.flags & SHRINKER_REGISTERED) { + if (journal->j_shrinker) { percpu_counter_destroy(&journal->j_checkpoint_jh_count); - unregister_shrinker(&journal->j_shrinker); + shrinker_free(journal->j_shrinker); } if (journal->j_proc_entry) jbd2_stats_proc_exit(journal); diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 52772c826c86..6dcbb4eb80fb 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -886,7 +886,7 @@ struct journal_s * Journal head shrinker, reclaim buffer's journal head which * has been written back. */ - struct shrinker j_shrinker; + struct shrinker *j_shrinker; /** * @j_checkpoint_jh_count: -- cgit v1.2.3 From 1720f5dd8d3af34d6023fb9e8c35e5e60e8b6643 Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:44:37 +0800 Subject: fs: super: dynamically allocate the s_shrink In preparation for implementing lockless slab shrink, use new APIs to dynamically allocate the s_shrink, so that it can be freed asynchronously via RCU. Then it doesn't need to wait for RCU read-side critical section when releasing the struct super_block. Link: https://lkml.kernel.org/r/20230911094444.68966-39-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Acked-by: David Sterba Cc: Chris Mason Cc: Josef Bacik Cc: Alexander Viro Cc: Christian Brauner Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Christian Koenig Cc: Chuck Lever Cc: Coly Li Cc: Dai Ngo Cc: Daniel Vetter Cc: Daniel Vetter Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: Dave Hansen Cc: David Airlie Cc: David Hildenbrand Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Greg Kroah-Hartman Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joel Fernandes (Google) Cc: Joonas Lahtinen Cc: Juergen Gross Cc: Kent Overstreet Cc: Kirill Tkhai Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Paul E. McKenney Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Roman Gushchin Cc: Sean Paul Cc: Sergey Senozhatsky Cc: Song Liu Cc: Stefano Stabellini Cc: Steven Price Cc: "Theodore Ts'o" Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- fs/btrfs/super.c | 2 +- fs/kernfs/mount.c | 2 +- fs/proc/root.c | 2 +- fs/super.c | 33 ++++++++++++++++++--------------- include/linux/fs.h | 2 +- 5 files changed, 22 insertions(+), 19 deletions(-) (limited to 'include/linux') diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 1a093ec0f7e3..b1798bed68f2 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1519,7 +1519,7 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, error = -EBUSY; } else { snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); - shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name, + shrinker_debugfs_rename(s->s_shrink, "sb-%s:%s", fs_type->name, s->s_id); btrfs_sb(s)->bdev_holder = fs_type; error = btrfs_fill_super(s, fs_devices, data); diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index c4bf26142eec..79b96e74a8a0 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -265,7 +265,7 @@ static int kernfs_fill_super(struct super_block *sb, struct kernfs_fs_context *k sb->s_time_gran = 1; /* sysfs dentries and inodes don't require IO to create */ - sb->s_shrink.seeks = 0; + sb->s_shrink->seeks = 0; /* get root inode, initialize and unlock it */ down_read(&kf_root->kernfs_rwsem); diff --git a/fs/proc/root.c b/fs/proc/root.c index 9191248f2dac..b55dbc70287b 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -188,7 +188,7 @@ static int proc_fill_super(struct super_block *s, struct fs_context *fc) s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; /* procfs dentries and inodes don't require IO to create */ - s->s_shrink.seeks = 0; + s->s_shrink->seeks = 0; pde_get(&proc_root); root_inode = proc_get_inode(s, &proc_root); diff --git a/fs/super.c b/fs/super.c index 2d762ce67f6e..adadf6689611 100644 --- a/fs/super.c +++ b/fs/super.c @@ -191,7 +191,7 @@ static unsigned long super_cache_scan(struct shrinker *shrink, long dentries; long inodes; - sb = container_of(shrink, struct super_block, s_shrink); + sb = shrink->private_data; /* * Deadlock avoidance. We may hold various FS locks, and we don't want @@ -244,7 +244,7 @@ static unsigned long super_cache_count(struct shrinker *shrink, struct super_block *sb; long total_objects = 0; - sb = container_of(shrink, struct super_block, s_shrink); + sb = shrink->private_data; /* * We don't call super_trylock_shared() here as it is a scalability @@ -306,7 +306,7 @@ static void destroy_unused_super(struct super_block *s) security_sb_free(s); put_user_ns(s->s_user_ns); kfree(s->s_subtype); - free_prealloced_shrinker(&s->s_shrink); + shrinker_free(s->s_shrink); /* no delays needed */ destroy_super_work(&s->destroy_work); } @@ -383,16 +383,19 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags, s->s_time_min = TIME64_MIN; s->s_time_max = TIME64_MAX; - s->s_shrink.seeks = DEFAULT_SEEKS; - s->s_shrink.scan_objects = super_cache_scan; - s->s_shrink.count_objects = super_cache_count; - s->s_shrink.batch = 1024; - s->s_shrink.flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE; - if (prealloc_shrinker(&s->s_shrink, "sb-%s", type->name)) + s->s_shrink = shrinker_alloc(SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE, + "sb-%s", type->name); + if (!s->s_shrink) goto fail; - if (list_lru_init_memcg(&s->s_dentry_lru, &s->s_shrink)) + + s->s_shrink->scan_objects = super_cache_scan; + s->s_shrink->count_objects = super_cache_count; + s->s_shrink->batch = 1024; + s->s_shrink->private_data = s; + + if (list_lru_init_memcg(&s->s_dentry_lru, s->s_shrink)) goto fail; - if (list_lru_init_memcg(&s->s_inode_lru, &s->s_shrink)) + if (list_lru_init_memcg(&s->s_inode_lru, s->s_shrink)) goto fail; return s; @@ -477,7 +480,7 @@ void deactivate_locked_super(struct super_block *s) { struct file_system_type *fs = s->s_type; if (atomic_dec_and_test(&s->s_active)) { - unregister_shrinker(&s->s_shrink); + shrinker_free(s->s_shrink); fs->kill_sb(s); kill_super_notify(s); @@ -818,7 +821,7 @@ retry: hlist_add_head(&s->s_instances, &s->s_type->fs_supers); spin_unlock(&sb_lock); get_filesystem(s->s_type); - register_shrinker_prepared(&s->s_shrink); + shrinker_register(s->s_shrink); return s; share_extant_sb: @@ -901,7 +904,7 @@ retry: hlist_add_head(&s->s_instances, &type->fs_supers); spin_unlock(&sb_lock); get_filesystem(type); - register_shrinker_prepared(&s->s_shrink); + shrinker_register(s->s_shrink); return s; } EXPORT_SYMBOL(sget); @@ -1522,7 +1525,7 @@ int setup_bdev_super(struct super_block *sb, int sb_flags, mutex_unlock(&bdev->bd_fsfreeze_mutex); snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev); - shrinker_debugfs_rename(&sb->s_shrink, "sb-%s:%s", sb->s_type->name, + shrinker_debugfs_rename(sb->s_shrink, "sb-%s:%s", sb->s_type->name, sb->s_id); sb_set_blocksize(sb, block_size(bdev)); return 0; diff --git a/include/linux/fs.h b/include/linux/fs.h index b528f063e8ff..fd539c9fef8e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1265,7 +1265,7 @@ struct super_block { const struct dentry_operations *s_d_op; /* default d_op for dentries */ - struct shrinker s_shrink; /* per-sb shrinker handle */ + struct shrinker *s_shrink; /* per-sb shrinker handle */ /* Number of inodes with nlink == 0 but still referenced */ atomic_long_t s_remove_count; -- cgit v1.2.3 From f2383e01507eeee8a1c1283d61a117a97d6c4ebe Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:44:38 +0800 Subject: mm: shrinker: remove old APIs Now no users are using the old APIs, just remove them. Link: https://lkml.kernel.org/r/20230911094444.68966-40-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Christian Brauner Cc: Christian Koenig Cc: Chuck Lever Cc: Coly Li Cc: Dai Ngo Cc: Daniel Vetter Cc: Daniel Vetter Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: Dave Hansen Cc: David Airlie Cc: David Hildenbrand Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Greg Kroah-Hartman Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joel Fernandes (Google) Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Kirill Tkhai Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Paul E. McKenney Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Roman Gushchin Cc: Sean Paul Cc: Sergey Senozhatsky Cc: Song Liu Cc: Stefano Stabellini Cc: Steven Price Cc: "Theodore Ts'o" Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- include/linux/shrinker.h | 8 --- mm/shrinker.c | 143 ----------------------------------------------- 2 files changed, 151 deletions(-) (limited to 'include/linux') diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index f4a5249f00b2..1d3899f37229 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -105,14 +105,6 @@ struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...); void shrinker_register(struct shrinker *shrinker); void shrinker_free(struct shrinker *shrinker); -extern int __printf(2, 3) prealloc_shrinker(struct shrinker *shrinker, - const char *fmt, ...); -extern void register_shrinker_prepared(struct shrinker *shrinker); -extern int __printf(2, 3) register_shrinker(struct shrinker *shrinker, - const char *fmt, ...); -extern void unregister_shrinker(struct shrinker *shrinker); -extern void free_prealloced_shrinker(struct shrinker *shrinker); - #ifdef CONFIG_SHRINKER_DEBUG extern int __printf(2, 3) shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...); diff --git a/mm/shrinker.c b/mm/shrinker.c index d1032a4d5684..736fa67e8454 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -655,146 +655,3 @@ void shrinker_free(struct shrinker *shrinker) kfree(shrinker); } EXPORT_SYMBOL_GPL(shrinker_free); - -/* - * Add a shrinker callback to be called from the vm. - */ -static int __prealloc_shrinker(struct shrinker *shrinker) -{ - unsigned int size; - int err; - - if (shrinker->flags & SHRINKER_MEMCG_AWARE) { - err = prealloc_memcg_shrinker(shrinker); - if (err != -ENOSYS) - return err; - - shrinker->flags &= ~SHRINKER_MEMCG_AWARE; - } - - size = sizeof(*shrinker->nr_deferred); - if (shrinker->flags & SHRINKER_NUMA_AWARE) - size *= nr_node_ids; - - shrinker->nr_deferred = kzalloc(size, GFP_KERNEL); - if (!shrinker->nr_deferred) - return -ENOMEM; - - return 0; -} - -#ifdef CONFIG_SHRINKER_DEBUG -int prealloc_shrinker(struct shrinker *shrinker, const char *fmt, ...) -{ - va_list ap; - int err; - - va_start(ap, fmt); - shrinker->name = kvasprintf_const(GFP_KERNEL, fmt, ap); - va_end(ap); - if (!shrinker->name) - return -ENOMEM; - - err = __prealloc_shrinker(shrinker); - if (err) { - kfree_const(shrinker->name); - shrinker->name = NULL; - } - - return err; -} -#else -int prealloc_shrinker(struct shrinker *shrinker, const char *fmt, ...) -{ - return __prealloc_shrinker(shrinker); -} -#endif - -void free_prealloced_shrinker(struct shrinker *shrinker) -{ -#ifdef CONFIG_SHRINKER_DEBUG - kfree_const(shrinker->name); - shrinker->name = NULL; -#endif - if (shrinker->flags & SHRINKER_MEMCG_AWARE) { - down_write(&shrinker_rwsem); - unregister_memcg_shrinker(shrinker); - up_write(&shrinker_rwsem); - return; - } - - kfree(shrinker->nr_deferred); - shrinker->nr_deferred = NULL; -} - -void register_shrinker_prepared(struct shrinker *shrinker) -{ - down_write(&shrinker_rwsem); - list_add_tail(&shrinker->list, &shrinker_list); - shrinker->flags |= SHRINKER_REGISTERED; - shrinker_debugfs_add(shrinker); - up_write(&shrinker_rwsem); -} - -static int __register_shrinker(struct shrinker *shrinker) -{ - int err = __prealloc_shrinker(shrinker); - - if (err) - return err; - register_shrinker_prepared(shrinker); - return 0; -} - -#ifdef CONFIG_SHRINKER_DEBUG -int register_shrinker(struct shrinker *shrinker, const char *fmt, ...) -{ - va_list ap; - int err; - - va_start(ap, fmt); - shrinker->name = kvasprintf_const(GFP_KERNEL, fmt, ap); - va_end(ap); - if (!shrinker->name) - return -ENOMEM; - - err = __register_shrinker(shrinker); - if (err) { - kfree_const(shrinker->name); - shrinker->name = NULL; - } - return err; -} -#else -int register_shrinker(struct shrinker *shrinker, const char *fmt, ...) -{ - return __register_shrinker(shrinker); -} -#endif -EXPORT_SYMBOL(register_shrinker); - -/* - * Remove one - */ -void unregister_shrinker(struct shrinker *shrinker) -{ - struct dentry *debugfs_entry; - int debugfs_id; - - if (!(shrinker->flags & SHRINKER_REGISTERED)) - return; - - down_write(&shrinker_rwsem); - list_del(&shrinker->list); - shrinker->flags &= ~SHRINKER_REGISTERED; - if (shrinker->flags & SHRINKER_MEMCG_AWARE) - unregister_memcg_shrinker(shrinker); - debugfs_entry = shrinker_debugfs_detach(shrinker, &debugfs_id); - up_write(&shrinker_rwsem); - - shrinker_debugfs_remove(debugfs_entry, debugfs_id); - - kfree(shrinker->nr_deferred); - shrinker->nr_deferred = NULL; -} -EXPORT_SYMBOL(unregister_shrinker); -- cgit v1.2.3 From 307bececcd1205bcb67a3c0d53a69db237ccc9d4 Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:44:39 +0800 Subject: mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred} Currently, we maintain two linear arrays per node per memcg, which are shrinker_info::map and shrinker_info::nr_deferred. And we need to resize them when the shrinker_nr_max is exceeded, that is, allocate a new array, and then copy the old array to the new array, and finally free the old array by RCU. For shrinker_info::map, we do set_bit() under the RCU lock, so we may set the value into the old map which is about to be freed. This may cause the value set to be lost. The current solution is not to copy the old map when resizing, but to set all the corresponding bits in the new map to 1. This solves the data loss problem, but bring the overhead of more pointless loops while doing memcg slab shrink. For shrinker_info::nr_deferred, we will only modify it under the read lock of shrinker_rwsem, so it will not run concurrently with the resizing. But after we make memcg slab shrink lockless, there will be the same data loss problem as shrinker_info::map, and we can't work around it like the map. For such resizable arrays, the most straightforward idea is to change it to xarray, like we did for list_lru [1]. We need to do xa_store() in the list_lru_add()-->set_shrinker_bit(), but this will cause memory allocation, and the list_lru_add() doesn't accept failure. A possible solution is to pre-allocate, but the location of pre-allocation is not well determined (such as deferred_split_shrinker case). Therefore, this commit chooses to introduce the following secondary array for shrinker_info::{map, nr_deferred}: +---------------+--------+--------+-----+ | shrinker_info | unit 0 | unit 1 | ... | (secondary array) +---------------+--------+--------+-----+ | v +---------------+-----+ | nr_deferred[] | map | (leaf array) +---------------+-----+ (shrinker_info_unit) The leaf array is never freed unless the memcg is destroyed. The secondary array will be resized every time the shrinker id exceeds shrinker_nr_max. So the shrinker_info_unit can be indexed from both the old and the new shrinker_info->unit[x]. Then even if we get the old secondary array under the RCU lock, the found map and nr_deferred are also true, so the updated nr_deferred and map will not be lost. [1]. https://lore.kernel.org/all/20220228122126.37293-13-songmuchun@bytedance.com/ [zhengqi.arch@bytedance.com: unlock the &shrinker_rwsem before the call to free_shrinker_info()] Link: https://lkml.kernel.org/r/20230928141517.12164-1-zhengqi.arch@bytedance.com Link: https://lkml.kernel.org/r/20230911094444.68966-41-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Christian Brauner Cc: Christian Koenig Cc: Chuck Lever Cc: Coly Li Cc: Dai Ngo Cc: Daniel Vetter Cc: Daniel Vetter Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: Dave Hansen Cc: David Airlie Cc: David Hildenbrand Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Greg Kroah-Hartman Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joel Fernandes (Google) Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Kirill Tkhai Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Paul E. McKenney Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Roman Gushchin Cc: Sean Paul Cc: Sergey Senozhatsky Cc: Song Liu Cc: Stefano Stabellini Cc: Steven Price Cc: "Theodore Ts'o" Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 12 +-- include/linux/shrinker.h | 17 +++ mm/shrinker.c | 250 ++++++++++++++++++++++++++++----------------- 3 files changed, 172 insertions(+), 107 deletions(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index e4e24da16d2c..031102ac9311 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -21,6 +21,7 @@ #include #include #include +#include struct mem_cgroup; struct obj_cgroup; @@ -88,17 +89,6 @@ struct mem_cgroup_reclaim_iter { unsigned int generation; }; -/* - * Bitmap and deferred work of shrinker::id corresponding to memcg-aware - * shrinkers, which have elements charged to this memcg. - */ -struct shrinker_info { - struct rcu_head rcu; - atomic_long_t *nr_deferred; - unsigned long *map; - int map_nr_max; -}; - struct lruvec_stats_percpu { /* Local (CPU and cgroup) state */ long state[NR_VM_NODE_STAT_ITEMS]; diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 1d3899f37229..ba5ac82b5dbd 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -5,6 +5,23 @@ #include #include +#define SHRINKER_UNIT_BITS BITS_PER_LONG + +/* + * Bitmap and deferred work of shrinker::id corresponding to memcg-aware + * shrinkers, which have elements charged to the memcg. + */ +struct shrinker_info_unit { + atomic_long_t nr_deferred[SHRINKER_UNIT_BITS]; + DECLARE_BITMAP(map, SHRINKER_UNIT_BITS); +}; + +struct shrinker_info { + struct rcu_head rcu; + int map_nr_max; + struct shrinker_info_unit *unit[]; +}; + /* * This struct is used to pass information from page reclaim to the shrinkers. * We consolidate the values for easier extension later. diff --git a/mm/shrinker.c b/mm/shrinker.c index 736fa67e8454..e9644cda80b5 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -12,15 +12,50 @@ DECLARE_RWSEM(shrinker_rwsem); #ifdef CONFIG_MEMCG static int shrinker_nr_max; -/* The shrinker_info is expanded in a batch of BITS_PER_LONG */ -static inline int shrinker_map_size(int nr_items) +static inline int shrinker_unit_size(int nr_items) { - return (DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long)); + return (DIV_ROUND_UP(nr_items, SHRINKER_UNIT_BITS) * sizeof(struct shrinker_info_unit *)); } -static inline int shrinker_defer_size(int nr_items) +static inline void shrinker_unit_free(struct shrinker_info *info, int start) { - return (round_up(nr_items, BITS_PER_LONG) * sizeof(atomic_long_t)); + struct shrinker_info_unit **unit; + int nr, i; + + if (!info) + return; + + unit = info->unit; + nr = DIV_ROUND_UP(info->map_nr_max, SHRINKER_UNIT_BITS); + + for (i = start; i < nr; i++) { + if (!unit[i]) + break; + + kfree(unit[i]); + unit[i] = NULL; + } +} + +static inline int shrinker_unit_alloc(struct shrinker_info *new, + struct shrinker_info *old, int nid) +{ + struct shrinker_info_unit *unit; + int nr = DIV_ROUND_UP(new->map_nr_max, SHRINKER_UNIT_BITS); + int start = old ? DIV_ROUND_UP(old->map_nr_max, SHRINKER_UNIT_BITS) : 0; + int i; + + for (i = start; i < nr; i++) { + unit = kzalloc_node(sizeof(*unit), GFP_KERNEL, nid); + if (!unit) { + shrinker_unit_free(new, start); + return -ENOMEM; + } + + new->unit[i] = unit; + } + + return 0; } void free_shrinker_info(struct mem_cgroup *memcg) @@ -32,6 +67,7 @@ void free_shrinker_info(struct mem_cgroup *memcg) for_each_node(nid) { pn = memcg->nodeinfo[nid]; info = rcu_dereference_protected(pn->shrinker_info, true); + shrinker_unit_free(info, 0); kvfree(info); rcu_assign_pointer(pn->shrinker_info, NULL); } @@ -40,28 +76,28 @@ void free_shrinker_info(struct mem_cgroup *memcg) int alloc_shrinker_info(struct mem_cgroup *memcg) { struct shrinker_info *info; - int nid, size, ret = 0; - int map_size, defer_size = 0; + int nid, ret = 0; + int array_size = 0; down_write(&shrinker_rwsem); - map_size = shrinker_map_size(shrinker_nr_max); - defer_size = shrinker_defer_size(shrinker_nr_max); - size = map_size + defer_size; + array_size = shrinker_unit_size(shrinker_nr_max); for_each_node(nid) { - info = kvzalloc_node(sizeof(*info) + size, GFP_KERNEL, nid); - if (!info) { - free_shrinker_info(memcg); - ret = -ENOMEM; - break; - } - info->nr_deferred = (atomic_long_t *)(info + 1); - info->map = (void *)info->nr_deferred + defer_size; + info = kvzalloc_node(sizeof(*info) + array_size, GFP_KERNEL, nid); + if (!info) + goto err; info->map_nr_max = shrinker_nr_max; + if (shrinker_unit_alloc(info, NULL, nid)) + goto err; rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); } up_write(&shrinker_rwsem); return ret; + +err: + up_write(&shrinker_rwsem); + free_shrinker_info(memcg); + return -ENOMEM; } static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg, @@ -71,15 +107,12 @@ static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg, lockdep_is_held(&shrinker_rwsem)); } -static int expand_one_shrinker_info(struct mem_cgroup *memcg, - int map_size, int defer_size, - int old_map_size, int old_defer_size, - int new_nr_max) +static int expand_one_shrinker_info(struct mem_cgroup *memcg, int new_size, + int old_size, int new_nr_max) { struct shrinker_info *new, *old; struct mem_cgroup_per_node *pn; int nid; - int size = map_size + defer_size; for_each_node(nid) { pn = memcg->nodeinfo[nid]; @@ -92,21 +125,17 @@ static int expand_one_shrinker_info(struct mem_cgroup *memcg, if (new_nr_max <= old->map_nr_max) continue; - new = kvmalloc_node(sizeof(*new) + size, GFP_KERNEL, nid); + new = kvmalloc_node(sizeof(*new) + new_size, GFP_KERNEL, nid); if (!new) return -ENOMEM; - new->nr_deferred = (atomic_long_t *)(new + 1); - new->map = (void *)new->nr_deferred + defer_size; new->map_nr_max = new_nr_max; - /* map: set all old bits, clear all new bits */ - memset(new->map, (int)0xff, old_map_size); - memset((void *)new->map + old_map_size, 0, map_size - old_map_size); - /* nr_deferred: copy old values, clear all new values */ - memcpy(new->nr_deferred, old->nr_deferred, old_defer_size); - memset((void *)new->nr_deferred + old_defer_size, 0, - defer_size - old_defer_size); + memcpy(new->unit, old->unit, old_size); + if (shrinker_unit_alloc(new, old, nid)) { + kvfree(new); + return -ENOMEM; + } rcu_assign_pointer(pn->shrinker_info, new); kvfree_rcu(old, rcu); @@ -118,9 +147,8 @@ static int expand_one_shrinker_info(struct mem_cgroup *memcg, static int expand_shrinker_info(int new_id) { int ret = 0; - int new_nr_max = round_up(new_id + 1, BITS_PER_LONG); - int map_size, defer_size = 0; - int old_map_size, old_defer_size = 0; + int new_nr_max = round_up(new_id + 1, SHRINKER_UNIT_BITS); + int new_size, old_size = 0; struct mem_cgroup *memcg; if (!root_mem_cgroup) @@ -128,15 +156,12 @@ static int expand_shrinker_info(int new_id) lockdep_assert_held(&shrinker_rwsem); - map_size = shrinker_map_size(new_nr_max); - defer_size = shrinker_defer_size(new_nr_max); - old_map_size = shrinker_map_size(shrinker_nr_max); - old_defer_size = shrinker_defer_size(shrinker_nr_max); + new_size = shrinker_unit_size(new_nr_max); + old_size = shrinker_unit_size(shrinker_nr_max); memcg = mem_cgroup_iter(NULL, NULL, NULL); do { - ret = expand_one_shrinker_info(memcg, map_size, defer_size, - old_map_size, old_defer_size, + ret = expand_one_shrinker_info(memcg, new_size, old_size, new_nr_max); if (ret) { mem_cgroup_iter_break(NULL, memcg); @@ -150,17 +175,34 @@ out: return ret; } +static inline int shrinker_id_to_index(int shrinker_id) +{ + return shrinker_id / SHRINKER_UNIT_BITS; +} + +static inline int shrinker_id_to_offset(int shrinker_id) +{ + return shrinker_id % SHRINKER_UNIT_BITS; +} + +static inline int calc_shrinker_id(int index, int offset) +{ + return index * SHRINKER_UNIT_BITS + offset; +} + void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id) { if (shrinker_id >= 0 && memcg && !mem_cgroup_is_root(memcg)) { struct shrinker_info *info; + struct shrinker_info_unit *unit; rcu_read_lock(); info = rcu_dereference(memcg->nodeinfo[nid]->shrinker_info); + unit = info->unit[shrinker_id_to_index(shrinker_id)]; if (!WARN_ON_ONCE(shrinker_id >= info->map_nr_max)) { /* Pairs with smp mb in shrink_slab() */ smp_mb__before_atomic(); - set_bit(shrinker_id, info->map); + set_bit(shrinker_id_to_offset(shrinker_id), unit->map); } rcu_read_unlock(); } @@ -209,26 +251,31 @@ static long xchg_nr_deferred_memcg(int nid, struct shrinker *shrinker, struct mem_cgroup *memcg) { struct shrinker_info *info; + struct shrinker_info_unit *unit; info = shrinker_info_protected(memcg, nid); - return atomic_long_xchg(&info->nr_deferred[shrinker->id], 0); + unit = info->unit[shrinker_id_to_index(shrinker->id)]; + return atomic_long_xchg(&unit->nr_deferred[shrinker_id_to_offset(shrinker->id)], 0); } static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker, struct mem_cgroup *memcg) { struct shrinker_info *info; + struct shrinker_info_unit *unit; info = shrinker_info_protected(memcg, nid); - return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]); + unit = info->unit[shrinker_id_to_index(shrinker->id)]; + return atomic_long_add_return(nr, &unit->nr_deferred[shrinker_id_to_offset(shrinker->id)]); } void reparent_shrinker_deferred(struct mem_cgroup *memcg) { - int i, nid; + int nid, index, offset; long nr; struct mem_cgroup *parent; struct shrinker_info *child_info, *parent_info; + struct shrinker_info_unit *child_unit, *parent_unit; parent = parent_mem_cgroup(memcg); if (!parent) @@ -239,9 +286,13 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) for_each_node(nid) { child_info = shrinker_info_protected(memcg, nid); parent_info = shrinker_info_protected(parent, nid); - for (i = 0; i < child_info->map_nr_max; i++) { - nr = atomic_long_read(&child_info->nr_deferred[i]); - atomic_long_add(nr, &parent_info->nr_deferred[i]); + for (index = 0; index < shrinker_id_to_index(child_info->map_nr_max); index++) { + child_unit = child_info->unit[index]; + parent_unit = parent_info->unit[index]; + for (offset = 0; offset < SHRINKER_UNIT_BITS; offset++) { + nr = atomic_long_read(&child_unit->nr_deferred[offset]); + atomic_long_add(nr, &parent_unit->nr_deferred[offset]); + } } } up_read(&shrinker_rwsem); @@ -407,7 +458,7 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid, { struct shrinker_info *info; unsigned long ret, freed = 0; - int i; + int offset, index = 0; if (!mem_cgroup_online(memcg)) return 0; @@ -419,56 +470,63 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid, if (unlikely(!info)) goto unlock; - for_each_set_bit(i, info->map, info->map_nr_max) { - struct shrink_control sc = { - .gfp_mask = gfp_mask, - .nid = nid, - .memcg = memcg, - }; - struct shrinker *shrinker; + for (; index < shrinker_id_to_index(info->map_nr_max); index++) { + struct shrinker_info_unit *unit; - shrinker = idr_find(&shrinker_idr, i); - if (unlikely(!shrinker || !(shrinker->flags & SHRINKER_REGISTERED))) { - if (!shrinker) - clear_bit(i, info->map); - continue; - } + unit = info->unit[index]; - /* Call non-slab shrinkers even though kmem is disabled */ - if (!memcg_kmem_online() && - !(shrinker->flags & SHRINKER_NONSLAB)) - continue; + for_each_set_bit(offset, unit->map, SHRINKER_UNIT_BITS) { + struct shrink_control sc = { + .gfp_mask = gfp_mask, + .nid = nid, + .memcg = memcg, + }; + struct shrinker *shrinker; + int shrinker_id = calc_shrinker_id(index, offset); - ret = do_shrink_slab(&sc, shrinker, priority); - if (ret == SHRINK_EMPTY) { - clear_bit(i, info->map); - /* - * After the shrinker reported that it had no objects to - * free, but before we cleared the corresponding bit in - * the memcg shrinker map, a new object might have been - * added. To make sure, we have the bit set in this - * case, we invoke the shrinker one more time and reset - * the bit if it reports that it is not empty anymore. - * The memory barrier here pairs with the barrier in - * set_shrinker_bit(): - * - * list_lru_add() shrink_slab_memcg() - * list_add_tail() clear_bit() - * - * set_bit() do_shrink_slab() - */ - smp_mb__after_atomic(); - ret = do_shrink_slab(&sc, shrinker, priority); - if (ret == SHRINK_EMPTY) - ret = 0; - else - set_shrinker_bit(memcg, nid, i); - } - freed += ret; + shrinker = idr_find(&shrinker_idr, shrinker_id); + if (unlikely(!shrinker || !(shrinker->flags & SHRINKER_REGISTERED))) { + if (!shrinker) + clear_bit(offset, unit->map); + continue; + } - if (rwsem_is_contended(&shrinker_rwsem)) { - freed = freed ? : 1; - break; + /* Call non-slab shrinkers even though kmem is disabled */ + if (!memcg_kmem_online() && + !(shrinker->flags & SHRINKER_NONSLAB)) + continue; + + ret = do_shrink_slab(&sc, shrinker, priority); + if (ret == SHRINK_EMPTY) { + clear_bit(offset, unit->map); + /* + * After the shrinker reported that it had no objects to + * free, but before we cleared the corresponding bit in + * the memcg shrinker map, a new object might have been + * added. To make sure, we have the bit set in this + * case, we invoke the shrinker one more time and reset + * the bit if it reports that it is not empty anymore. + * The memory barrier here pairs with the barrier in + * set_shrinker_bit(): + * + * list_lru_add() shrink_slab_memcg() + * list_add_tail() clear_bit() + * + * set_bit() do_shrink_slab() + */ + smp_mb__after_atomic(); + ret = do_shrink_slab(&sc, shrinker, priority); + if (ret == SHRINK_EMPTY) + ret = 0; + else + set_shrinker_bit(memcg, nid, shrinker_id); + } + freed += ret; + + if (rwsem_is_contended(&shrinker_rwsem)) { + freed = freed ? : 1; + goto unlock; + } } } unlock: -- cgit v1.2.3 From ca1d36b823944f24b5755311e95883fb5fdb807b Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:44:41 +0800 Subject: mm: shrinker: make global slab shrink lockless The shrinker_rwsem is a global read-write lock in shrinkers subsystem, which protects most operations such as slab shrink, registration and unregistration of shrinkers, etc. This can easily cause problems in the following cases. 1) When the memory pressure is high and there are many filesystems mounted or unmounted at the same time, slab shrink will be affected (down_read_trylock() failed). Such as the real workload mentioned by Kirill Tkhai: ``` One of the real workloads from my experience is start of an overcommitted node containing many starting containers after node crash (or many resuming containers after reboot for kernel update). In these cases memory pressure is huge, and the node goes round in long reclaim. ``` 2) If a shrinker is blocked (such as the case mentioned in [1]) and a writer comes in (such as mount a fs), then this writer will be blocked and cause all subsequent shrinker-related operations to be blocked. Even if there is no competitor when shrinking slab, there may still be a problem. The down_read_trylock() may become a perf hotspot with frequent calls to shrink_slab(). Because of the poor multicore scalability of atomic operations, this can lead to a significant drop in IPC (instructions per cycle). We used to implement the lockless slab shrink with SRCU [2], but then kernel test robot reported -88.8% regression in stress-ng.ramfs.ops_per_sec test case [3], so we reverted it [4]. This commit uses the refcount+RCU method [5] proposed by Dave Chinner to re-implement the lockless global slab shrink. The memcg slab shrink is handled in the subsequent patch. For now, all shrinker instances are converted to dynamically allocated and will be freed by call_rcu(). So we can use rcu_read_{lock,unlock}() to ensure that the shrinker instance is valid. And the shrinker instance will not be run again after unregistration. So the structure that records the pointer of shrinker instance can be safely freed without waiting for the RCU read-side critical section. In this way, while we implement the lockless slab shrink, we don't need to be blocked in unregister_shrinker(). The following are the test results: stress-ng --timeout 60 --times --verify --metrics-brief --ramfs 9 & 1) Before applying this patchset: setting to a 60 second run per stressor dispatching hogs: 9 ramfs stressor bogo ops real time usr time sys time bogo ops/s bogo ops/s (secs) (secs) (secs) (real time) (usr+sys time) ramfs 473062 60.00 8.00 279.13 7884.12 1647.59 for a 60.01s run time: 1440.34s available CPU time 7.99s user time ( 0.55%) 279.13s system time ( 19.38%) 287.12s total time ( 19.93%) load average: 7.12 2.99 1.15 successful run completed in 60.01s (1 min, 0.01 secs) 2) After applying this patchset: setting to a 60 second run per stressor dispatching hogs: 9 ramfs stressor bogo ops real time usr time sys time bogo ops/s bogo ops/s (secs) (secs) (secs) (real time) (usr+sys time) ramfs 477165 60.00 8.13 281.34 7952.55 1648.40 for a 60.01s run time: 1440.33s available CPU time 8.12s user time ( 0.56%) 281.34s system time ( 19.53%) 289.46s total time ( 20.10%) load average: 6.98 3.03 1.19 successful run completed in 60.01s (1 min, 0.01 secs) We can see that the ops/s has hardly changed. [1]. https://lore.kernel.org/lkml/20191129214541.3110-1-ptikhomirov@virtuozzo.com/ [2]. https://lore.kernel.org/lkml/20230313112819.38938-1-zhengqi.arch@bytedance.com/ [3]. https://lore.kernel.org/lkml/202305230837.db2c233f-yujie.liu@intel.com/ [4]. https://lore.kernel.org/all/20230609081518.3039120-1-qi.zheng@linux.dev/ [5]. https://lore.kernel.org/lkml/ZIJhou1d55d4H1s0@dread.disaster.area/ Link: https://lkml.kernel.org/r/20230911094444.68966-43-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Christian Brauner Cc: Christian Koenig Cc: Chuck Lever Cc: Coly Li Cc: Dai Ngo Cc: Daniel Vetter Cc: Daniel Vetter Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: Dave Hansen Cc: David Airlie Cc: David Hildenbrand Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Greg Kroah-Hartman Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jason Wang Cc: Jeff Layton Cc: Jeffle Xu Cc: Joel Fernandes (Google) Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Kirill Tkhai Cc: Marijn Suijten Cc: "Michael S. Tsirkin" Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Paul E. McKenney Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Roman Gushchin Cc: Sean Paul Cc: Sergey Senozhatsky Cc: Song Liu Cc: Stefano Stabellini Cc: Steven Price Cc: "Theodore Ts'o" Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: Yue Hu Signed-off-by: Andrew Morton --- include/linux/shrinker.h | 24 +++++++++++++ mm/shrinker.c | 89 ++++++++++++++++++++++++++++++++++++------------ 2 files changed, 92 insertions(+), 21 deletions(-) (limited to 'include/linux') diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index ba5ac82b5dbd..e4f93120e0ab 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -4,6 +4,8 @@ #include #include +#include +#include #define SHRINKER_UNIT_BITS BITS_PER_LONG @@ -87,6 +89,17 @@ struct shrinker { int seeks; /* seeks to recreate an obj */ unsigned flags; + /* + * The reference count of this shrinker. Registered shrinker have an + * initial refcount of 1, then the lookup operations are now allowed + * to use it via shrinker_try_get(). Later in the unregistration step, + * the initial refcount will be discarded, and will free the shrinker + * asynchronously via RCU after its refcount reaches 0. + */ + refcount_t refcount; + struct completion done; /* use to wait for refcount to reach 0 */ + struct rcu_head rcu; + void *private_data; /* These are for internal use */ @@ -122,6 +135,17 @@ struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...); void shrinker_register(struct shrinker *shrinker); void shrinker_free(struct shrinker *shrinker); +static inline bool shrinker_try_get(struct shrinker *shrinker) +{ + return refcount_inc_not_zero(&shrinker->refcount); +} + +static inline void shrinker_put(struct shrinker *shrinker) +{ + if (refcount_dec_and_test(&shrinker->refcount)) + complete(&shrinker->done); +} + #ifdef CONFIG_SHRINKER_DEBUG extern int __printf(2, 3) shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...); diff --git a/mm/shrinker.c b/mm/shrinker.c index e2e832b15803..9bb2e61092b3 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -2,6 +2,7 @@ #include #include #include +#include #include #include "internal.h" @@ -577,33 +578,50 @@ unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg, if (!mem_cgroup_disabled() && !mem_cgroup_is_root(memcg)) return shrink_slab_memcg(gfp_mask, nid, memcg, priority); - if (!down_read_trylock(&shrinker_rwsem)) - goto out; - - list_for_each_entry(shrinker, &shrinker_list, list) { + /* + * lockless algorithm of global shrink. + * + * In the unregistration setp, the shrinker will be freed asynchronously + * via RCU after its refcount reaches 0. So both rcu_read_lock() and + * shrinker_try_get() can be used to ensure the existence of the shrinker. + * + * So in the global shrink: + * step 1: use rcu_read_lock() to guarantee existence of the shrinker + * and the validity of the shrinker_list walk. + * step 2: use shrinker_try_get() to try get the refcount, if successful, + * then the existence of the shrinker can also be guaranteed, + * so we can release the RCU lock to do do_shrink_slab() that + * may sleep. + * step 3: *MUST* to reacquire the RCU lock before calling shrinker_put(), + * which ensures that neither this shrinker nor the next shrinker + * will be freed in the next traversal operation. + * step 4: do shrinker_put() paired with step 2 to put the refcount, + * if the refcount reaches 0, then wake up the waiter in + * shrinker_free() by calling complete(). + */ + rcu_read_lock(); + list_for_each_entry_rcu(shrinker, &shrinker_list, list) { struct shrink_control sc = { .gfp_mask = gfp_mask, .nid = nid, .memcg = memcg, }; + if (!shrinker_try_get(shrinker)) + continue; + + rcu_read_unlock(); + ret = do_shrink_slab(&sc, shrinker, priority); if (ret == SHRINK_EMPTY) ret = 0; freed += ret; - /* - * Bail out if someone want to register a new shrinker to - * prevent the registration from being stalled for long periods - * by parallel ongoing shrinking. - */ - if (rwsem_is_contended(&shrinker_rwsem)) { - freed = freed ? : 1; - break; - } + + rcu_read_lock(); + shrinker_put(shrinker); } - up_read(&shrinker_rwsem); -out: + rcu_read_unlock(); cond_resched(); return freed; } @@ -676,13 +694,29 @@ void shrinker_register(struct shrinker *shrinker) } down_write(&shrinker_rwsem); - list_add_tail(&shrinker->list, &shrinker_list); + list_add_tail_rcu(&shrinker->list, &shrinker_list); shrinker->flags |= SHRINKER_REGISTERED; shrinker_debugfs_add(shrinker); up_write(&shrinker_rwsem); + + init_completion(&shrinker->done); + /* + * Now the shrinker is fully set up, take the first reference to it to + * indicate that lookup operations are now allowed to use it via + * shrinker_try_get(). + */ + refcount_set(&shrinker->refcount, 1); } EXPORT_SYMBOL_GPL(shrinker_register); +static void shrinker_free_rcu_cb(struct rcu_head *head) +{ + struct shrinker *shrinker = container_of(head, struct shrinker, rcu); + + kfree(shrinker->nr_deferred); + kfree(shrinker); +} + void shrinker_free(struct shrinker *shrinker) { struct dentry *debugfs_entry = NULL; @@ -691,9 +725,25 @@ void shrinker_free(struct shrinker *shrinker) if (!shrinker) return; + if (shrinker->flags & SHRINKER_REGISTERED) { + /* drop the initial refcount */ + shrinker_put(shrinker); + /* + * Wait for all lookups of the shrinker to complete, after that, + * no shrinker is running or will run again, then we can safely + * free it asynchronously via RCU and safely free the structure + * where the shrinker is located, such as super_block etc. + */ + wait_for_completion(&shrinker->done); + } + down_write(&shrinker_rwsem); if (shrinker->flags & SHRINKER_REGISTERED) { - list_del(&shrinker->list); + /* + * Now we can safely remove it from the shrinker_list and then + * free it. + */ + list_del_rcu(&shrinker->list); debugfs_entry = shrinker_debugfs_detach(shrinker, &debugfs_id); shrinker->flags &= ~SHRINKER_REGISTERED; } @@ -707,9 +757,6 @@ void shrinker_free(struct shrinker *shrinker) if (debugfs_entry) shrinker_debugfs_remove(debugfs_entry, debugfs_id); - kfree(shrinker->nr_deferred); - shrinker->nr_deferred = NULL; - - kfree(shrinker); + call_rcu(&shrinker->rcu, shrinker_free_rcu_cb); } EXPORT_SYMBOL_GPL(shrinker_free); -- cgit v1.2.3 From 09c550508a4b8f7844b197cc16877dd0f7c42d8f Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Wed, 13 Sep 2023 14:51:13 +0200 Subject: mm/rmap: pass folio to hugepage_add_anon_rmap() Let's pass a folio; we are always mapping the entire thing. Link: https://lkml.kernel.org/r/20230913125113.313322-7-david@redhat.com Signed-off-by: David Hildenbrand Cc: Matthew Wilcox Cc: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton --- include/linux/rmap.h | 2 +- mm/migrate.c | 2 +- mm/rmap.c | 8 +++----- 3 files changed, 5 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 51cc21ebb568..d22f4d21a11c 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -203,7 +203,7 @@ void folio_add_file_rmap_range(struct folio *, struct page *, unsigned int nr, void page_remove_rmap(struct page *, struct vm_area_struct *, bool compound); -void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, +void hugepage_add_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address, rmap_t flags); void hugepage_add_new_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address); diff --git a/mm/migrate.c b/mm/migrate.c index 2053b54556ca..eb6bc4053bc4 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -249,7 +249,7 @@ static bool remove_migration_pte(struct folio *folio, pte = arch_make_huge_pte(pte, shift, vma->vm_flags); if (folio_test_anon(folio)) - hugepage_add_anon_rmap(new, vma, pvmw.address, + hugepage_add_anon_rmap(folio, vma, pvmw.address, rmap_flags); else page_dup_file_rmap(new, true); diff --git a/mm/rmap.c b/mm/rmap.c index ed4b602bcbd5..d24e2c36372e 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2542,18 +2542,16 @@ void rmap_walk_locked(struct folio *folio, struct rmap_walk_control *rwc) * * RMAP_COMPOUND is ignored. */ -void hugepage_add_anon_rmap(struct page *page, struct vm_area_struct *vma, +void hugepage_add_anon_rmap(struct folio *folio, struct vm_area_struct *vma, unsigned long address, rmap_t flags) { - struct folio *folio = page_folio(page); - VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); atomic_inc(&folio->_entire_mapcount); if (flags & RMAP_EXCLUSIVE) - SetPageAnonExclusive(page); + SetPageAnonExclusive(&folio->page); VM_WARN_ON_FOLIO(folio_entire_mapcount(folio) > 1 && - PageAnonExclusive(page), folio); + PageAnonExclusive(&folio->page), folio); } void hugepage_add_new_anon_rmap(struct folio *folio, -- cgit v1.2.3 From 73eab3ca481e5be0f1fd8140365d604482f84ee1 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 13 Sep 2023 17:51:27 +0800 Subject: mm: migrate: convert migrate_misplaced_page() to migrate_misplaced_folio() At present, numa balance only support base page and PMD-mapped THP, but we will expand to support to migrate large folio/pte-mapped THP in the future, it is better to make migrate_misplaced_page() to take a folio instead of a page, and rename it to migrate_misplaced_folio(), it is a preparation, also this remove several compound_head() calls. Link: https://lkml.kernel.org/r/20230913095131.2426871-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Zi Yan Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Signed-off-by: Andrew Morton --- include/linux/migrate.h | 4 ++-- mm/huge_memory.c | 2 +- mm/memory.c | 2 +- mm/migrate.c | 39 +++++++++++++++++++++------------------ 4 files changed, 25 insertions(+), 22 deletions(-) (limited to 'include/linux') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 711dd9412561..2ce13e8a309b 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -142,10 +142,10 @@ const struct movable_operations *page_movable_ops(struct page *page) } #ifdef CONFIG_NUMA_BALANCING -int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, +int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma, int node); #else -static inline int migrate_misplaced_page(struct page *page, +static inline int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma, int node) { return -EAGAIN; /* can't migrate now */ diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1cfd83e91748..5c20e43782e4 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1567,7 +1567,7 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) spin_unlock(vmf->ptl); writable = false; - migrated = migrate_misplaced_page(page, vma, target_nid); + migrated = migrate_misplaced_folio(page_folio(page), vma, target_nid); if (migrated) { flags |= TNF_MIGRATED; page_nid = target_nid; diff --git a/mm/memory.c b/mm/memory.c index 0739ccb00e61..d956b231e835 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4812,7 +4812,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) writable = false; /* Migrate to the requested node */ - if (migrate_misplaced_page(page, vma, target_nid)) { + if (migrate_misplaced_folio(page_folio(page), vma, target_nid)) { page_nid = target_nid; flags |= TNF_MIGRATED; } else { diff --git a/mm/migrate.c b/mm/migrate.c index 1f1aebe8da18..1b848f6b5fbc 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2516,55 +2516,58 @@ static int numamigrate_isolate_folio(pg_data_t *pgdat, struct folio *folio) } /* - * Attempt to migrate a misplaced page to the specified destination + * Attempt to migrate a misplaced folio to the specified destination * node. Caller is expected to have an elevated reference count on - * the page that will be dropped by this function before returning. + * the folio that will be dropped by this function before returning. */ -int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, - int node) +int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma, + int node) { pg_data_t *pgdat = NODE_DATA(node); int isolated; int nr_remaining; unsigned int nr_succeeded; LIST_HEAD(migratepages); - int nr_pages = thp_nr_pages(page); + int nr_pages = folio_nr_pages(folio); /* - * Don't migrate file pages that are mapped in multiple processes + * Don't migrate file folios that are mapped in multiple processes * with execute permissions as they are probably shared libraries. + * To check if the folio is shared, ideally we want to make sure + * every page is mapped to the same process. Doing that is very + * expensive, so check the estimated mapcount of the folio instead. */ - if (page_mapcount(page) != 1 && page_is_file_lru(page) && + if (folio_estimated_sharers(folio) != 1 && folio_is_file_lru(folio) && (vma->vm_flags & VM_EXEC)) goto out; /* - * Also do not migrate dirty pages as not all filesystems can move - * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. + * Also do not migrate dirty folios as not all filesystems can move + * dirty folios in MIGRATE_ASYNC mode which is a waste of cycles. */ - if (page_is_file_lru(page) && PageDirty(page)) + if (folio_is_file_lru(folio) && folio_test_dirty(folio)) goto out; - isolated = numamigrate_isolate_folio(pgdat, page_folio(page)); + isolated = numamigrate_isolate_folio(pgdat, folio); if (!isolated) goto out; - list_add(&page->lru, &migratepages); + list_add(&folio->lru, &migratepages); nr_remaining = migrate_pages(&migratepages, alloc_misplaced_dst_folio, NULL, node, MIGRATE_ASYNC, MR_NUMA_MISPLACED, &nr_succeeded); if (nr_remaining) { if (!list_empty(&migratepages)) { - list_del(&page->lru); - mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + - page_is_file_lru(page), -nr_pages); - putback_lru_page(page); + list_del(&folio->lru); + node_stat_mod_folio(folio, NR_ISOLATED_ANON + + folio_is_file_lru(folio), -nr_pages); + folio_putback_lru(folio); } isolated = 0; } if (nr_succeeded) { count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded); - if (!node_is_toptier(page_to_nid(page)) && node_is_toptier(node)) + if (!node_is_toptier(folio_nid(folio)) && node_is_toptier(node)) mod_node_page_state(pgdat, PGPROMOTE_SUCCESS, nr_succeeded); } @@ -2572,7 +2575,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, return isolated; out: - put_page(page); + folio_put(folio); return 0; } #endif /* CONFIG_NUMA_BALANCING */ -- cgit v1.2.3 From 2a41815784e029cbef571511384f00fa40f2a82e Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 14 Sep 2023 16:00:04 +0100 Subject: buffer: pass GFP flags to folio_alloc_buffers() Patch series "Add and use bdev_getblk()", v2. This patch series fixes a bug reported by Hui Zhu; see proposed patches v1 and v2: https://lore.kernel.org/linux-fsdevel/20230811035705.3296-1-teawaterz@linux.alibaba.com/ https://lore.kernel.org/linux-fsdevel/20230811071519.1094-1-teawaterz@linux.alibaba.com/ I decided to go in a rather different direction for this fix, and fix a related problem at the same time. I don't think there's any urgency to rush this into Linus' tree, nor have I marked it for stable. Reasonable people may disagree. This patch (of 8): Instead of creating entirely new flags, inherit them from grow_dev_page(). The other callers create the same flags that this function used to create. Link: https://lkml.kernel.org/r/20230914150011.843330-1-willy@infradead.org Link: https://lkml.kernel.org/r/20230914150011.843330-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Hui Zhu Signed-off-by: Andrew Morton --- fs/buffer.c | 17 +++++++++-------- include/linux/buffer_head.h | 2 +- 2 files changed, 10 insertions(+), 9 deletions(-) (limited to 'include/linux') diff --git a/fs/buffer.c b/fs/buffer.c index 12e9a71c693d..32338b7cfeb9 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -915,16 +915,12 @@ int remove_inode_buffers(struct inode *inode) * which may not fail from ordinary buffer allocations. */ struct buffer_head *folio_alloc_buffers(struct folio *folio, unsigned long size, - bool retry) + gfp_t gfp) { struct buffer_head *bh, *head; - gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT; long offset; struct mem_cgroup *memcg, *old_memcg; - if (retry) - gfp |= __GFP_NOFAIL; - /* The folio lock pins the memcg */ memcg = folio_memcg(folio); old_memcg = set_active_memcg(memcg); @@ -967,7 +963,11 @@ EXPORT_SYMBOL_GPL(folio_alloc_buffers); struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, bool retry) { - return folio_alloc_buffers(page_folio(page), size, retry); + gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT; + if (retry) + gfp |= __GFP_NOFAIL; + + return folio_alloc_buffers(page_folio(page), size, gfp); } EXPORT_SYMBOL_GPL(alloc_page_buffers); @@ -1069,7 +1069,7 @@ grow_dev_page(struct block_device *bdev, sector_t block, goto failed; } - bh = folio_alloc_buffers(folio, size, true); + bh = folio_alloc_buffers(folio, size, gfp_mask | __GFP_ACCOUNT); /* * Link the folio to the buffers and initialise them. Take the @@ -1644,8 +1644,9 @@ void folio_create_empty_buffers(struct folio *folio, unsigned long blocksize, unsigned long b_state) { struct buffer_head *bh, *head, *tail; + gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT | __GFP_NOFAIL; - head = folio_alloc_buffers(folio, blocksize, true); + head = folio_alloc_buffers(folio, blocksize, gfp); bh = head; do { bh->b_state |= b_state; diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 44e9de51eedf..67d94d2be475 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -198,7 +198,7 @@ void touch_buffer(struct buffer_head *bh); void folio_set_bh(struct buffer_head *bh, struct folio *folio, unsigned long offset); struct buffer_head *folio_alloc_buffers(struct folio *folio, unsigned long size, - bool retry); + gfp_t gfp); struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, bool retry); void create_empty_buffers(struct page *, unsigned long, -- cgit v1.2.3 From 3ed65f04aac4d1cd025f30ee3fac174bcbf2b018 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 14 Sep 2023 16:00:05 +0100 Subject: buffer: hoist GFP flags from grow_dev_page() to __getblk_gfp() grow_dev_page() is only called by grow_buffers(). grow_buffers() is only called by __getblk_slow() and __getblk_slow() is only called from __getblk_gfp(), so it is safe to move the GFP flags setting all the way up. With that done, add a new bdev_getblk() entry point that leaves the GFP flags the way the caller specified them. [willy@infradead.org: fix grow_dev_page() error handling] Link: https://lkml.kernel.org/r/ZRREEIwqiy5DijKB@casper.infradead.org Link: https://lkml.kernel.org/r/20230914150011.843330-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Hui Zhu Cc: Dan Carpenter Signed-off-by: Andrew Morton --- fs/buffer.c | 61 +++++++++++++++++++++++++++++---------------- include/linux/buffer_head.h | 2 ++ 2 files changed, 42 insertions(+), 21 deletions(-) (limited to 'include/linux') diff --git a/fs/buffer.c b/fs/buffer.c index 32338b7cfeb9..80e96c1fcd33 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1043,20 +1043,11 @@ grow_dev_page(struct block_device *bdev, sector_t block, struct buffer_head *bh; sector_t end_block; int ret = 0; - gfp_t gfp_mask; - - gfp_mask = mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS) | gfp; - - /* - * XXX: __getblk_slow() can not really deal with failure and - * will endlessly loop on improvised global reclaim. Prefer - * looping in the allocator rather than here, at least that - * code knows what it's doing. - */ - gfp_mask |= __GFP_NOFAIL; folio = __filemap_get_folio(inode->i_mapping, index, - FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp_mask); + FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp); + if (IS_ERR(folio)) + return PTR_ERR(folio); bh = folio_buffers(folio); if (bh) { @@ -1069,7 +1060,10 @@ grow_dev_page(struct block_device *bdev, sector_t block, goto failed; } - bh = folio_alloc_buffers(folio, size, gfp_mask | __GFP_ACCOUNT); + ret = -ENOMEM; + bh = folio_alloc_buffers(folio, size, gfp | __GFP_ACCOUNT); + if (!bh) + goto failed; /* * Link the folio to the buffers and initialise them. Take the @@ -1420,24 +1414,49 @@ __find_get_block(struct block_device *bdev, sector_t block, unsigned size) } EXPORT_SYMBOL(__find_get_block); +/** + * bdev_getblk - Get a buffer_head in a block device's buffer cache. + * @bdev: The block device. + * @block: The block number. + * @size: The size of buffer_heads for this @bdev. + * @gfp: The memory allocation flags to use. + * + * In contrast to __getblk_gfp(), the @gfp flags must be all of the flags; + * they are not augmented with the mapping's GFP flags. + * + * Return: The buffer head, or NULL if memory could not be allocated. + */ +struct buffer_head *bdev_getblk(struct block_device *bdev, sector_t block, + unsigned size, gfp_t gfp) +{ + struct buffer_head *bh = __find_get_block(bdev, block, size); + + might_alloc(gfp); + if (bh) + return bh; + + return __getblk_slow(bdev, block, size, gfp); +} +EXPORT_SYMBOL(bdev_getblk); + /* * __getblk_gfp() will locate (and, if necessary, create) the buffer_head * which corresponds to the passed block_device, block and size. The * returned buffer has its reference count incremented. - * - * __getblk_gfp() will lock up the machine if grow_dev_page's - * try_to_free_buffers() attempt is failing. FIXME, perhaps? */ struct buffer_head * __getblk_gfp(struct block_device *bdev, sector_t block, unsigned size, gfp_t gfp) { - struct buffer_head *bh = __find_get_block(bdev, block, size); + gfp |= mapping_gfp_constraint(bdev->bd_inode->i_mapping, ~__GFP_FS); - might_sleep(); - if (bh == NULL) - bh = __getblk_slow(bdev, block, size, gfp); - return bh; + /* + * Prefer looping in the allocator rather than here, at least that + * code knows what it's doing. + */ + gfp |= __GFP_NOFAIL; + + return bdev_getblk(bdev, block, size, gfp); } EXPORT_SYMBOL(__getblk_gfp); diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 67d94d2be475..7825bb3d63a7 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -227,6 +227,8 @@ void __wait_on_buffer(struct buffer_head *); wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block, unsigned size); +struct buffer_head *bdev_getblk(struct block_device *bdev, sector_t block, + unsigned size, gfp_t gfp); struct buffer_head *__getblk_gfp(struct block_device *bdev, sector_t block, unsigned size, gfp_t gfp); void __brelse(struct buffer_head *); -- cgit v1.2.3 From c645e65c0675dd4df7ee68b995154dc1c1e7ce3b Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 14 Sep 2023 16:00:08 +0100 Subject: buffer: convert getblk_unmovable() and __getblk() to use bdev_getblk() Move these two functions up in the file for the benefit of the next patch, and pass in all of the GFP flags to use instead of the partial GFP flags used by __getblk_gfp(). Link: https://lkml.kernel.org/r/20230914150011.843330-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Hui Zhu Signed-off-by: Andrew Morton --- include/linux/buffer_head.h | 36 ++++++++++++++++++++++-------------- 1 file changed, 22 insertions(+), 14 deletions(-) (limited to 'include/linux') diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 7825bb3d63a7..9a3ca5f6d63d 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -340,6 +340,28 @@ sb_breadahead(struct super_block *sb, sector_t block) __breadahead(sb->s_bdev, block, sb->s_blocksize); } +static inline struct buffer_head *getblk_unmovable(struct block_device *bdev, + sector_t block, unsigned size) +{ + gfp_t gfp; + + gfp = mapping_gfp_constraint(bdev->bd_inode->i_mapping, ~__GFP_FS); + gfp |= __GFP_NOFAIL; + + return bdev_getblk(bdev, block, size, gfp); +} + +static inline struct buffer_head *__getblk(struct block_device *bdev, + sector_t block, unsigned size) +{ + gfp_t gfp; + + gfp = mapping_gfp_constraint(bdev->bd_inode->i_mapping, ~__GFP_FS); + gfp |= __GFP_MOVABLE | __GFP_NOFAIL; + + return bdev_getblk(bdev, block, size, gfp); +} + static inline struct buffer_head * sb_getblk(struct super_block *sb, sector_t block) { @@ -387,20 +409,6 @@ static inline void lock_buffer(struct buffer_head *bh) __lock_buffer(bh); } -static inline struct buffer_head *getblk_unmovable(struct block_device *bdev, - sector_t block, - unsigned size) -{ - return __getblk_gfp(bdev, block, size, 0); -} - -static inline struct buffer_head *__getblk(struct block_device *bdev, - sector_t block, - unsigned size) -{ - return __getblk_gfp(bdev, block, size, __GFP_MOVABLE); -} - static inline void bh_readahead(struct buffer_head *bh, blk_opf_t op_flags) { if (!buffer_uptodate(bh) && trylock_buffer(bh)) { -- cgit v1.2.3 From 4b9c8b1919323f7f359376ca31a4c721cb2b3acf Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 14 Sep 2023 16:00:09 +0100 Subject: buffer: convert sb_getblk() to call __getblk() Now that __getblk() is in the right place in the file, it is trivial to call it from sb_getblk(). Link: https://lkml.kernel.org/r/20230914150011.843330-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Hui Zhu Signed-off-by: Andrew Morton --- include/linux/buffer_head.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 9a3ca5f6d63d..b294e2cccbae 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -362,13 +362,12 @@ static inline struct buffer_head *__getblk(struct block_device *bdev, return bdev_getblk(bdev, block, size, gfp); } -static inline struct buffer_head * -sb_getblk(struct super_block *sb, sector_t block) +static inline struct buffer_head *sb_getblk(struct super_block *sb, + sector_t block) { - return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE); + return __getblk(sb->s_bdev, block, sb->s_blocksize); } - static inline struct buffer_head * sb_getblk_gfp(struct super_block *sb, sector_t block, gfp_t gfp) { -- cgit v1.2.3 From 8a83ac54940d27b8f56d766e1cb270d150fedd50 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 14 Sep 2023 16:00:10 +0100 Subject: ext4: call bdev_getblk() from sb_getblk_gfp() Most of the callers of sb_getblk_gfp() already assumed that they were passing the entire GFP flags to use. Fix up the two callers that didn't, and remove the __GFP_NOFAIL from them since they both appear to correctly handle failure. Link: https://lkml.kernel.org/r/20230914150011.843330-8-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Hui Zhu Signed-off-by: Andrew Morton --- fs/ext4/super.c | 10 ++++++++-- include/linux/buffer_head.h | 6 +++--- 2 files changed, 11 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 268d812b0add..c00ec159dea5 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -244,13 +244,19 @@ static struct buffer_head *__ext4_sb_bread_gfp(struct super_block *sb, struct buffer_head *ext4_sb_bread(struct super_block *sb, sector_t block, blk_opf_t op_flags) { - return __ext4_sb_bread_gfp(sb, block, op_flags, __GFP_MOVABLE); + gfp_t gfp = mapping_gfp_constraint(sb->s_bdev->bd_inode->i_mapping, + ~__GFP_FS) | __GFP_MOVABLE; + + return __ext4_sb_bread_gfp(sb, block, op_flags, gfp); } struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb, sector_t block) { - return __ext4_sb_bread_gfp(sb, block, 0, 0); + gfp_t gfp = mapping_gfp_constraint(sb->s_bdev->bd_inode->i_mapping, + ~__GFP_FS); + + return __ext4_sb_bread_gfp(sb, block, 0, gfp); } void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block) diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index b294e2cccbae..22f13eece719 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -368,10 +368,10 @@ static inline struct buffer_head *sb_getblk(struct super_block *sb, return __getblk(sb->s_bdev, block, sb->s_blocksize); } -static inline struct buffer_head * -sb_getblk_gfp(struct super_block *sb, sector_t block, gfp_t gfp) +static inline struct buffer_head *sb_getblk_gfp(struct super_block *sb, + sector_t block, gfp_t gfp) { - return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, gfp); + return bdev_getblk(sb->s_bdev, block, sb->s_blocksize, gfp); } static inline struct buffer_head * -- cgit v1.2.3 From 93b13ecaa713e1fcbf23b7483eec065d300c5ad8 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 14 Sep 2023 16:00:11 +0100 Subject: buffer: remove __getblk_gfp() Inline it into __bread_gfp(). Link: https://lkml.kernel.org/r/20230914150011.843330-9-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Hui Zhu Signed-off-by: Andrew Morton --- fs/buffer.c | 36 +++++++++++------------------------- include/linux/buffer_head.h | 2 -- 2 files changed, 11 insertions(+), 27 deletions(-) (limited to 'include/linux') diff --git a/fs/buffer.c b/fs/buffer.c index edd118594565..edec8652788c 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1421,9 +1421,6 @@ EXPORT_SYMBOL(__find_get_block); * @size: The size of buffer_heads for this @bdev. * @gfp: The memory allocation flags to use. * - * In contrast to __getblk_gfp(), the @gfp flags must be all of the flags; - * they are not augmented with the mapping's GFP flags. - * * Return: The buffer head, or NULL if memory could not be allocated. */ struct buffer_head *bdev_getblk(struct block_device *bdev, sector_t block, @@ -1439,27 +1436,6 @@ struct buffer_head *bdev_getblk(struct block_device *bdev, sector_t block, } EXPORT_SYMBOL(bdev_getblk); -/* - * __getblk_gfp() will locate (and, if necessary, create) the buffer_head - * which corresponds to the passed block_device, block and size. The - * returned buffer has its reference count incremented. - */ -struct buffer_head * -__getblk_gfp(struct block_device *bdev, sector_t block, - unsigned size, gfp_t gfp) -{ - gfp |= mapping_gfp_constraint(bdev->bd_inode->i_mapping, ~__GFP_FS); - - /* - * Prefer looping in the allocator rather than here, at least that - * code knows what it's doing. - */ - gfp |= __GFP_NOFAIL; - - return bdev_getblk(bdev, block, size, gfp); -} -EXPORT_SYMBOL(__getblk_gfp); - /* * Do async read-ahead on a buffer.. */ @@ -1491,7 +1467,17 @@ struct buffer_head * __bread_gfp(struct block_device *bdev, sector_t block, unsigned size, gfp_t gfp) { - struct buffer_head *bh = __getblk_gfp(bdev, block, size, gfp); + struct buffer_head *bh; + + gfp |= mapping_gfp_constraint(bdev->bd_inode->i_mapping, ~__GFP_FS); + + /* + * Prefer looping in the allocator rather than here, at least that + * code knows what it's doing. + */ + gfp |= __GFP_NOFAIL; + + bh = bdev_getblk(bdev, block, size, gfp); if (likely(bh) && !buffer_uptodate(bh)) bh = __bread_slow(bh); diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 22f13eece719..3dc4720e4773 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -229,8 +229,6 @@ struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block, unsigned size); struct buffer_head *bdev_getblk(struct block_device *bdev, sector_t block, unsigned size, gfp_t gfp); -struct buffer_head *__getblk_gfp(struct block_device *bdev, sector_t block, - unsigned size, gfp_t gfp); void __brelse(struct buffer_head *); void __bforget(struct buffer_head *); void __breadahead(struct block_device *, sector_t block, unsigned int size); -- cgit v1.2.3 From 3dfbb555c98ac55b9d911f9af0e35014b445fb41 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Thu, 14 Sep 2023 15:16:39 +0200 Subject: mm, vmscan: remove ISOLATE_UNMAPPED This isolate_mode_t flag is effectively unused since 89f6c88a6ab4 ("mm: __isolate_lru_page_prepare() in isolate_migratepages_block()") as sc->may_unmap is now checked directly (and only node_reclaim has a mode that sets it to 0). The last remaining place is mm_vmscan_lru_isolate tracepoint for the isolate_mode parameter. That one was mainly used to indicate the active/inactive mode, which the trace-vmscan-postprocess.pl script consumed, but that got silently broken. After fixing the script by the previous patch, it does not need the isolate_mode anymore. So just remove the parameter and with that the whole ISOLATE_UNMAPPED flag. Link: https://lkml.kernel.org/r/20230914131637.12204-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka Cc: Hugh Dickins Cc: Mel Gorman Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- Documentation/trace/postprocess/trace-vmscan-postprocess.pl | 8 ++++---- include/linux/mmzone.h | 2 -- include/trace/events/vmscan.h | 8 ++------ mm/vmscan.c | 3 +-- 4 files changed, 7 insertions(+), 14 deletions(-) (limited to 'include/linux') diff --git a/Documentation/trace/postprocess/trace-vmscan-postprocess.pl b/Documentation/trace/postprocess/trace-vmscan-postprocess.pl index 725d41a8d4ef..048dc0dbce64 100644 --- a/Documentation/trace/postprocess/trace-vmscan-postprocess.pl +++ b/Documentation/trace/postprocess/trace-vmscan-postprocess.pl @@ -112,7 +112,7 @@ my $regex_direct_end_default = 'nr_reclaimed=([0-9]*)'; my $regex_kswapd_wake_default = 'nid=([0-9]*) order=([0-9]*)'; my $regex_kswapd_sleep_default = 'nid=([0-9]*)'; my $regex_wakeup_kswapd_default = 'nid=([0-9]*) order=([0-9]*) gfp_flags=([A-Z_|]*)'; -my $regex_lru_isolate_default = 'isolate_mode=([0-9]*) classzone=([0-9]*) order=([0-9]*) nr_requested=([0-9]*) nr_scanned=([0-9]*) nr_skipped=([0-9]*) nr_taken=([0-9]*) lru=([a-z_]*)'; +my $regex_lru_isolate_default = 'classzone=([0-9]*) order=([0-9]*) nr_requested=([0-9]*) nr_scanned=([0-9]*) nr_skipped=([0-9]*) nr_taken=([0-9]*) lru=([a-z_]*)'; my $regex_lru_shrink_inactive_default = 'nid=([0-9]*) nr_scanned=([0-9]*) nr_reclaimed=([0-9]*) nr_dirty=([0-9]*) nr_writeback=([0-9]*) nr_congested=([0-9]*) nr_immediate=([0-9]*) nr_activate_anon=([0-9]*) nr_activate_file=([0-9]*) nr_ref_keep=([0-9]*) nr_unmap_fail=([0-9]*) priority=([0-9]*) flags=([A-Z_|]*)'; my $regex_lru_shrink_active_default = 'lru=([A-Z_]*) nr_taken=([0-9]*) nr_active=([0-9]*) nr_deactivated=([0-9]*) nr_referenced=([0-9]*) priority=([0-9]*) flags=([A-Z_|]*)' ; my $regex_writepage_default = 'page=([0-9a-f]*) pfn=([0-9]*) flags=([A-Z_|]*)'; @@ -204,7 +204,7 @@ $regex_wakeup_kswapd = generate_traceevent_regex( $regex_lru_isolate = generate_traceevent_regex( "vmscan/mm_vmscan_lru_isolate", $regex_lru_isolate_default, - "isolate_mode", classzone", "order", + "classzone", "order", "nr_requested", "nr_scanned", "nr_skipped", "nr_taken", "lru"); $regex_lru_shrink_inactive = generate_traceevent_regex( @@ -379,8 +379,8 @@ EVENT_PROCESS: print " $regex_lru_isolate/o\n"; next; } - my $nr_scanned = $5; - my $lru = $8; + my $nr_scanned = $4; + my $lru = $7; # To closer match vmstat scanning statistics, only count # inactive lru as scanning diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 4106fbc5b4b3..486587fcd27f 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -639,8 +639,6 @@ struct lruvec { #endif }; -/* Isolate unmapped pages */ -#define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x2) /* Isolate for asynchronous migration */ #define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x4) /* Isolate unevictable pages */ diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h index d2123dd960d5..1a488c30afa5 100644 --- a/include/trace/events/vmscan.h +++ b/include/trace/events/vmscan.h @@ -285,10 +285,9 @@ TRACE_EVENT(mm_vmscan_lru_isolate, unsigned long nr_scanned, unsigned long nr_skipped, unsigned long nr_taken, - isolate_mode_t isolate_mode, int lru), - TP_ARGS(highest_zoneidx, order, nr_requested, nr_scanned, nr_skipped, nr_taken, isolate_mode, lru), + TP_ARGS(highest_zoneidx, order, nr_requested, nr_scanned, nr_skipped, nr_taken, lru), TP_STRUCT__entry( __field(int, highest_zoneidx) @@ -297,7 +296,6 @@ TRACE_EVENT(mm_vmscan_lru_isolate, __field(unsigned long, nr_scanned) __field(unsigned long, nr_skipped) __field(unsigned long, nr_taken) - __field(unsigned int, isolate_mode) __field(int, lru) ), @@ -308,7 +306,6 @@ TRACE_EVENT(mm_vmscan_lru_isolate, __entry->nr_scanned = nr_scanned; __entry->nr_skipped = nr_skipped; __entry->nr_taken = nr_taken; - __entry->isolate_mode = (__force unsigned int)isolate_mode; __entry->lru = lru; ), @@ -316,8 +313,7 @@ TRACE_EVENT(mm_vmscan_lru_isolate, * classzone is previous name of the highest_zoneidx. * Reason not to change it is the ABI requirement of the tracepoint. */ - TP_printk("isolate_mode=%d classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_skipped=%lu nr_taken=%lu lru=%s", - __entry->isolate_mode, + TP_printk("classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_skipped=%lu nr_taken=%lu lru=%s", __entry->highest_zoneidx, __entry->order, __entry->nr_requested, diff --git a/mm/vmscan.c b/mm/vmscan.c index acf115468bf8..3df0e2a59052 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1689,8 +1689,7 @@ move: } *nr_scanned = total_scan; trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, - total_scan, skipped, nr_taken, - sc->may_unmap ? 0 : ISOLATE_UNMAPPED, lru); + total_scan, skipped, nr_taken, lru); update_lru_sizes(lruvec, lru, nr_zone_taken); return nr_taken; } -- cgit v1.2.3 From 4472edf63d6630e6cf65e205b4fc8c3c94d0afe5 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Thu, 14 Sep 2023 02:15:23 +0000 Subject: mm/damon/core: use number of passed access sampling as a timer DAMON sleeps for sampling interval after each sampling, and check if the aggregation interval and the ops update interval have passed using ktime_get_coarse_ts64() and baseline timestamps for the intervals. That design is for making the operations occur at deterministic timing regardless of the time that spend for each work. However, it turned out it is not that useful, and incur not-that-intuitive results. After all, timer functions, and especially sleep functions that DAMON uses to wait for specific timing, are not necessarily strictly accurate. It is legal design, so no problem. However, depending on such inaccuracies, the nr_accesses can be larger than aggregation interval divided by sampling interval. For example, with the default setting (5 ms sampling interval and 100 ms aggregation interval) we frequently show regions having nr_accesses larger than 20. Also, if the execution of a DAMOS scheme takes a long time, next aggregation could happen before enough number of samples are collected. This is not what usual users would intuitively expect. Since access check sampling is the smallest unit work of DAMON, using the number of passed sampling intervals as the DAMON-internal timer can easily avoid these problems. That is, convert aggregation and ops update intervals to numbers of sampling intervals that need to be passed before those operations be executed, count the number of passed sampling intervals, and invoke the operations as soon as the specific amount of sampling intervals passed. Make the change. Note that this could make a behavioral change to settings that using intervals that not aligned by the sampling interval. For example, if the sampling interval is 5 ms and the aggregation interval is 12 ms, DAMON effectively uses 15 ms as its aggregation interval, because it checks whether the aggregation interval after sleeping the sampling interval. This change will make DAMON to effectively use 10 ms as aggregation interval, since it uses 'aggregation interval / sampling interval * sampling interval' as the effective aggregation interval, and we don't use floating point types. Usual users would have used aligned intervals, so this behavioral change is not expected to make any meaningful impact, so just make this change. Link: https://lkml.kernel.org/r/20230914021523.60649-1-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/damon.h | 14 ++++++-- mm/damon/core.c | 96 +++++++++++++++++++++++++-------------------------- 2 files changed, 59 insertions(+), 51 deletions(-) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index ab3089de1478..9a32b8fd0bd3 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -524,8 +524,18 @@ struct damon_ctx { struct damon_attrs attrs; /* private: internal use only */ - struct timespec64 last_aggregation; - struct timespec64 last_ops_update; + /* number of sample intervals that passed since this context started */ + unsigned long passed_sample_intervals; + /* + * number of sample intervals that should be passed before next + * aggregation + */ + unsigned long next_aggregation_sis; + /* + * number of sample intervals that should be passed before next ops + * update + */ + unsigned long next_ops_update_sis; /* public: */ struct task_struct *kdamond; diff --git a/mm/damon/core.c b/mm/damon/core.c index 3ca34a252a3c..c5b7296c69a0 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -427,8 +427,10 @@ struct damon_ctx *damon_new_ctx(void) ctx->attrs.aggr_interval = 100 * 1000; ctx->attrs.ops_update_interval = 60 * 1000 * 1000; - ktime_get_coarse_ts64(&ctx->last_aggregation); - ctx->last_ops_update = ctx->last_aggregation; + ctx->passed_sample_intervals = 0; + /* These will be set from kdamond_init_intervals_sis() */ + ctx->next_aggregation_sis = 0; + ctx->next_ops_update_sis = 0; mutex_init(&ctx->kdamond_lock); @@ -552,6 +554,9 @@ static void damon_update_monitoring_results(struct damon_ctx *ctx, */ int damon_set_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs) { + unsigned long sample_interval = attrs->sample_interval ? + attrs->sample_interval : 1; + if (attrs->min_nr_regions < 3) return -EINVAL; if (attrs->min_nr_regions > attrs->max_nr_regions) @@ -559,6 +564,11 @@ int damon_set_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs) if (attrs->sample_interval > attrs->aggr_interval) return -EINVAL; + ctx->next_aggregation_sis = ctx->passed_sample_intervals + + attrs->aggr_interval / sample_interval; + ctx->next_ops_update_sis = ctx->passed_sample_intervals + + attrs->ops_update_interval / sample_interval; + damon_update_monitoring_results(ctx, attrs); ctx->attrs = *attrs; return 0; @@ -732,38 +742,6 @@ int damon_stop(struct damon_ctx **ctxs, int nr_ctxs) return err; } -/* - * damon_check_reset_time_interval() - Check if a time interval is elapsed. - * @baseline: the time to check whether the interval has elapsed since - * @interval: the time interval (microseconds) - * - * See whether the given time interval has passed since the given baseline - * time. If so, it also updates the baseline to current time for next check. - * - * Return: true if the time interval has passed, or false otherwise. - */ -static bool damon_check_reset_time_interval(struct timespec64 *baseline, - unsigned long interval) -{ - struct timespec64 now; - - ktime_get_coarse_ts64(&now); - if ((timespec64_to_ns(&now) - timespec64_to_ns(baseline)) < - interval * 1000) - return false; - *baseline = now; - return true; -} - -/* - * Check whether it is time to flush the aggregated information - */ -static bool kdamond_aggregate_interval_passed(struct damon_ctx *ctx) -{ - return damon_check_reset_time_interval(&ctx->last_aggregation, - ctx->attrs.aggr_interval); -} - /* * Reset the aggregated monitoring results ('nr_accesses' of each region). */ @@ -1274,18 +1252,6 @@ static void kdamond_split_regions(struct damon_ctx *ctx) last_nr_regions = nr_regions; } -/* - * Check whether it is time to check and apply the operations-related data - * structures. - * - * Returns true if it is. - */ -static bool kdamond_need_update_operations(struct damon_ctx *ctx) -{ - return damon_check_reset_time_interval(&ctx->last_ops_update, - ctx->attrs.ops_update_interval); -} - /* * Check whether current monitoring should be stopped * @@ -1397,6 +1363,17 @@ static int kdamond_wait_activation(struct damon_ctx *ctx) return -EBUSY; } +static void kdamond_init_intervals_sis(struct damon_ctx *ctx) +{ + unsigned long sample_interval = ctx->attrs.sample_interval ? + ctx->attrs.sample_interval : 1; + + ctx->passed_sample_intervals = 0; + ctx->next_aggregation_sis = ctx->attrs.aggr_interval / sample_interval; + ctx->next_ops_update_sis = ctx->attrs.ops_update_interval / + sample_interval; +} + /* * The monitoring daemon that runs as a kernel thread */ @@ -1410,6 +1387,8 @@ static int kdamond_fn(void *data) pr_debug("kdamond (%d) starts\n", current->pid); + kdamond_init_intervals_sis(ctx); + if (ctx->ops.init) ctx->ops.init(ctx); if (ctx->callback.before_start && ctx->callback.before_start(ctx)) @@ -1418,6 +1397,17 @@ static int kdamond_fn(void *data) sz_limit = damon_region_sz_limit(ctx); while (!kdamond_need_stop(ctx)) { + /* + * ctx->attrs and ctx->next_{aggregation,ops_update}_sis could + * be changed from after_wmarks_check() or after_aggregation() + * callbacks. Read the values here, and use those for this + * iteration. That is, damon_set_attrs() updated new values + * are respected from next iteration. + */ + unsigned long next_aggregation_sis = ctx->next_aggregation_sis; + unsigned long next_ops_update_sis = ctx->next_ops_update_sis; + unsigned long sample_interval = ctx->attrs.sample_interval; + if (kdamond_wait_activation(ctx)) break; @@ -1427,12 +1417,17 @@ static int kdamond_fn(void *data) ctx->callback.after_sampling(ctx)) break; - kdamond_usleep(ctx->attrs.sample_interval); + kdamond_usleep(sample_interval); + ctx->passed_sample_intervals++; if (ctx->ops.check_accesses) max_nr_accesses = ctx->ops.check_accesses(ctx); - if (kdamond_aggregate_interval_passed(ctx)) { + sample_interval = ctx->attrs.sample_interval ? + ctx->attrs.sample_interval : 1; + if (ctx->passed_sample_intervals == next_aggregation_sis) { + ctx->next_aggregation_sis = next_aggregation_sis + + ctx->attrs.aggr_interval / sample_interval; kdamond_merge_regions(ctx, max_nr_accesses / 10, sz_limit); @@ -1447,7 +1442,10 @@ static int kdamond_fn(void *data) ctx->ops.reset_aggregated(ctx); } - if (kdamond_need_update_operations(ctx)) { + if (ctx->passed_sample_intervals == next_ops_update_sis) { + ctx->next_ops_update_sis = next_ops_update_sis + + ctx->attrs.ops_update_interval / + sample_interval; if (ctx->ops.update) ctx->ops.update(ctx); sz_limit = damon_region_sz_limit(ctx); -- cgit v1.2.3 From 78fbfb155d204428119310d1b9df665ab88da6e8 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 15 Sep 2023 02:52:44 +0000 Subject: mm/damon/core: define and use a dedicated function for region access rate update Patch series "mm/damon: provide pseudo-moving sum based access rate". DAMON checks the access to each region for every sampling interval, increase the access rate counter of the region, namely nr_accesses, if the access was made. For every aggregation interval, the counter is reset. The counter is exposed to users to be used as a metric showing the relative access rate (frequency) of each region. In other words, DAMON provides access rate of each region in every aggregation interval. The aggregation avoids temporal access pattern changes making things confusing. However, this also makes a few DAMON-related operations to unnecessarily need to be aligned to the aggregation interval. This can restrict the flexibility of DAMON applications, especially when the aggregation interval is huge. To provide the monitoring results in finer-grained timing while keeping handling of temporal access pattern change, this patchset implements a pseudo-moving sum based access rate metric. It is pseudo-moving sum because strict moving sum implementation would need to keep all values for last time window, and that could incur high overhead of there could be arbitrary number of values in a time window. Especially in case of the nr_accesses, since the sampling interval and aggregation interval can arbitrarily set and the past values should be maintained for every region, it could be risky. The pseudo-moving sum assumes there were no temporal access pattern change in last discrete time window to remove the needs for keeping the list of the last time window values. As a result, it beocmes not strict moving sum implementation, but provides a reasonable accuracy. Also, it keeps an important property of the moving sum. That is, the moving sum becomes same to discrete-window based sum at the time that aligns to the time window. This means using the pseudo moving sum based nr_accesses makes no change to users who shows the value for every aggregation interval. Patches Sequence ---------------- The sequence of the patches is as follows. The first four patches are for preparation of the change. The first two (patches 1 and 2) implements a helper function for nr_accesses update and eliminate corner case that skips use of the function, respectively. Following two (patches 3 and 4) respectively implement the pseudo-moving sum function and its simple unit test case. Two patches for making DAMON to use the pseudo-moving sum follow. The fifthe one (patch 5) introduces a new field for representing the pseudo-moving sum-based access rate of each region, and the sixth one makes the new representation to actually updated with the pseudo-moving sum function. Last two patches (patches 7 and 8) makes followup fixes for skipping unnecessary updates and marking the moving sum function as static, respectively. This patch (of 8): Each DAMON operarions set is updating nr_accesses field of each damon_region for each of their access check results, from the check_accesses() callback. Directly accessing the field could make things complex to manage and change in future. Define and use a dedicated function for the purpose. Link: https://lkml.kernel.org/r/20230915025251.72816-1-sj@kernel.org Link: https://lkml.kernel.org/r/20230915025251.72816-2-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Signed-off-by: Andrew Morton --- include/linux/damon.h | 5 ++++- mm/damon/core.c | 16 ++++++++++++++++ mm/damon/paddr.c | 6 ++---- mm/damon/vaddr.c | 6 ++---- 4 files changed, 24 insertions(+), 9 deletions(-) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index 9a32b8fd0bd3..17c504d236b9 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -45,7 +45,9 @@ struct damon_addr_range { * * @nr_accesses is reset to zero for every &damon_attrs->aggr_interval and be * increased for every &damon_attrs->sample_interval if an access to the region - * during the last sampling interval is found. + * during the last sampling interval is found. The update of this field should + * not be done with direct access but with the helper function, + * damon_update_region_access_rate(). * * @age is initially zero, increased for each aggregation interval, and reset * to zero again if the access frequency is significantly changed. If two @@ -620,6 +622,7 @@ void damon_add_region(struct damon_region *r, struct damon_target *t); void damon_destroy_region(struct damon_region *r, struct damon_target *t); int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges, unsigned int nr_ranges); +void damon_update_region_access_rate(struct damon_region *r, bool accessed); struct damos_filter *damos_new_filter(enum damos_filter_type type, bool matching); diff --git a/mm/damon/core.c b/mm/damon/core.c index c5b7296c69a0..10532159323a 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1549,6 +1549,22 @@ int damon_set_region_biggest_system_ram_default(struct damon_target *t, return damon_set_regions(t, &addr_range, 1); } +/** + * damon_update_region_access_rate() - Update the access rate of a region. + * @r: The DAMON region to update for its access check result. + * @accessed: Whether the region has accessed during last sampling interval. + * + * Update the access rate of a region with the region's last sampling interval + * access check result. + * + * Usually this will be called by &damon_operations->check_accesses callback. + */ +void damon_update_region_access_rate(struct damon_region *r, bool accessed) +{ + if (accessed) + r->nr_accesses++; +} + static int __init damon_init(void) { damon_region_cache = KMEM_CACHE(damon_region, 0); diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index 909db25efb35..44f21860b555 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -157,14 +157,12 @@ static void __damon_pa_check_access(struct damon_region *r) /* If the region is in the last checked page, reuse the result */ if (ALIGN_DOWN(last_addr, last_folio_sz) == ALIGN_DOWN(r->sampling_addr, last_folio_sz)) { - if (last_accessed) - r->nr_accesses++; + damon_update_region_access_rate(r, last_accessed); return; } last_accessed = damon_pa_young(r->sampling_addr, &last_folio_sz); - if (last_accessed) - r->nr_accesses++; + damon_update_region_access_rate(r, last_accessed); last_addr = r->sampling_addr; } diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c index cf8a9fc5c9d1..53371bbec605 100644 --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -567,14 +567,12 @@ static void __damon_va_check_access(struct mm_struct *mm, /* If the region is in the last checked page, reuse the result */ if (same_target && (ALIGN_DOWN(last_addr, last_folio_sz) == ALIGN_DOWN(r->sampling_addr, last_folio_sz))) { - if (last_accessed) - r->nr_accesses++; + damon_update_region_access_rate(r, last_accessed); return; } last_accessed = damon_va_young(mm, r->sampling_addr, &last_folio_sz); - if (last_accessed) - r->nr_accesses++; + damon_update_region_access_rate(r, last_accessed); last_addr = r->sampling_addr; } -- cgit v1.2.3 From d2c062ade07ffd206dd16bf085f02abc59651309 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 15 Sep 2023 02:52:46 +0000 Subject: mm/damon/core: implement a pseudo-moving sum function For values that continuously change, moving average or sum are good ways to provide fast updates while handling temporal and errorneous variability of the value. For example, the access rate counter (nr_accesses) is calculated as a sum of the number of positive sampled access check results that collected during a discrete time window (aggregation interval), and hence it handles temporal and errorneous access check results, but provides the update only for every aggregation interval. Using a moving sum method for that could allow providing the value for every sampling interval. That could be useful for getting monitoring results snapshot or running DAMOS in fine-grained timing. However, supporting the moving sum for cases that number of samples in the time window is arbirary could impose high overhead, since the number of past values that it needs to keep could be too high. The nr_accesses would also be one of the cases. To mitigate the overhead, implement a pseudo-moving sum function that only provides an estimated pseudo-moving sum. It assumes there was no error in last discrete time window and subtract constant portion of last discrete time window sum. Note that the function is not strictly implementing the moving sum, but it keeps a property of moving sum, which makes the value same to the dsicrete-window based sum for each time window-aligned timing. Hence, people collecting the value in the old timings would show no difference. Link: https://lkml.kernel.org/r/20230915025251.72816-4-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Signed-off-by: Andrew Morton --- include/linux/damon.h | 2 ++ mm/damon/core.c | 40 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index 17c504d236b9..487a545a11b4 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -622,6 +622,8 @@ void damon_add_region(struct damon_region *r, struct damon_target *t); void damon_destroy_region(struct damon_region *r, struct damon_target *t); int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges, unsigned int nr_ranges); +unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum, + unsigned int len_window, unsigned int new_value); void damon_update_region_access_rate(struct damon_region *r, bool accessed); struct damos_filter *damos_new_filter(enum damos_filter_type type, diff --git a/mm/damon/core.c b/mm/damon/core.c index 10532159323a..b005dc15009f 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1549,6 +1549,46 @@ int damon_set_region_biggest_system_ram_default(struct damon_target *t, return damon_set_regions(t, &addr_range, 1); } +/* + * damon_moving_sum() - Calculate an inferred moving sum value. + * @mvsum: Inferred sum of the last @len_window values. + * @nomvsum: Non-moving sum of the last discrete @len_window window values. + * @len_window: The number of last values to take care of. + * @new_value: New value that will be added to the pseudo moving sum. + * + * Moving sum (moving average * window size) is good for handling noise, but + * the cost of keeping past values can be high for arbitrary window size. This + * function implements a lightweight pseudo moving sum function that doesn't + * keep the past window values. + * + * It simply assumes there was no noise in the past, and get the no-noise + * assumed past value to drop from @nomvsum and @len_window. @nomvsum is a + * non-moving sum of the last window. For example, if @len_window is 10 and we + * have 25 values, @nomvsum is the sum of the 11th to 20th values of the 25 + * values. Hence, this function simply drops @nomvsum / @len_window from + * given @mvsum and add @new_value. + * + * For example, if @len_window is 10 and @nomvsum is 50, the last 10 values for + * the last window could be vary, e.g., 0, 10, 0, 10, 0, 10, 0, 0, 0, 20. For + * calculating next moving sum with a new value, we should drop 0 from 50 and + * add the new value. However, this function assumes it got value 5 for each + * of the last ten times. Based on the assumption, when the next value is + * measured, it drops the assumed past value, 5 from the current sum, and add + * the new value to get the updated pseduo-moving average. + * + * This means the value could have errors, but the errors will be disappeared + * for every @len_window aligned calls. For example, if @len_window is 10, the + * pseudo moving sum with 11th value to 19th value would have an error. But + * the sum with 20th value will not have the error. + * + * Return: Pseudo-moving average after getting the @new_value. + */ +unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum, + unsigned int len_window, unsigned int new_value) +{ + return mvsum - nomvsum / len_window + new_value; +} + /** * damon_update_region_access_rate() - Update the access rate of a region. * @r: The DAMON region to update for its access check result. -- cgit v1.2.3 From 80333828ea7728ebe85d079bb5c1467eb9fc6c8c Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 15 Sep 2023 02:52:48 +0000 Subject: mm/damon/core: introduce nr_accesses_bp Add yet another representation of the access rate of each region, namely nr_accesses_bp. It is just same to the nr_accesses but represents the value in basis point (1 in 10,000), and updated at once in every aggregation interval. That is, moving_accesses_bp is just nr_accesses * 10000. This may seems useless at the moment. However, it will be useful for representing less than one nr_accesses value that will be needed to make moving sum-based nr_accesses. Link: https://lkml.kernel.org/r/20230915025251.72816-6-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Signed-off-by: Andrew Morton --- include/linux/damon.h | 5 +++++ mm/damon/core-test.h | 5 +++++ mm/damon/core.c | 6 ++++++ 3 files changed, 16 insertions(+) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index 487a545a11b4..15f24b23c9a0 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -40,6 +40,7 @@ struct damon_addr_range { * @ar: The address range of the region. * @sampling_addr: Address of the sample for the next access check. * @nr_accesses: Access frequency of this region. + * @nr_accesses_bp: @nr_accesses in basis point (0.01%). * @list: List head for siblings. * @age: Age of this region. * @@ -49,6 +50,9 @@ struct damon_addr_range { * not be done with direct access but with the helper function, * damon_update_region_access_rate(). * + * @nr_accesses_bp is another representation of @nr_accesses in basis point + * (1 in 10,000) that updated every aggregation interval. + * * @age is initially zero, increased for each aggregation interval, and reset * to zero again if the access frequency is significantly changed. If two * regions are merged into a new region, both @nr_accesses and @age of the new @@ -58,6 +62,7 @@ struct damon_region { struct damon_addr_range ar; unsigned long sampling_addr; unsigned int nr_accesses; + unsigned int nr_accesses_bp; struct list_head list; unsigned int age; diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h index c539f0e8377e..79f1f12e0dd5 100644 --- a/mm/damon/core-test.h +++ b/mm/damon/core-test.h @@ -94,6 +94,7 @@ static void damon_test_aggregate(struct kunit *test) for (ir = 0; ir < 3; ir++) { r = damon_new_region(saddr[it][ir], eaddr[it][ir]); r->nr_accesses = accesses[it][ir]; + r->nr_accesses_bp = accesses[it][ir] * 10000; damon_add_region(r, t); } it++; @@ -147,9 +148,11 @@ static void damon_test_merge_two(struct kunit *test) t = damon_new_target(); r = damon_new_region(0, 100); r->nr_accesses = 10; + r->nr_accesses_bp = 100000; damon_add_region(r, t); r2 = damon_new_region(100, 300); r2->nr_accesses = 20; + r2->nr_accesses_bp = 200000; damon_add_region(r2, t); damon_merge_two_regions(t, r, r2); @@ -196,6 +199,7 @@ static void damon_test_merge_regions_of(struct kunit *test) for (i = 0; i < ARRAY_SIZE(sa); i++) { r = damon_new_region(sa[i], ea[i]); r->nr_accesses = nrs[i]; + r->nr_accesses_bp = nrs[i] * 10000; damon_add_region(r, t); } @@ -297,6 +301,7 @@ static void damon_test_update_monitoring_result(struct kunit *test) struct damon_region *r = damon_new_region(3, 7); r->nr_accesses = 15; + r->nr_accesses_bp = 150000; r->age = 20; new_attrs = (struct damon_attrs){ diff --git a/mm/damon/core.c b/mm/damon/core.c index b005dc15009f..ce85c00b0a4c 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -128,6 +128,7 @@ struct damon_region *damon_new_region(unsigned long start, unsigned long end) region->ar.start = start; region->ar.end = end; region->nr_accesses = 0; + region->nr_accesses_bp = 0; INIT_LIST_HEAD(®ion->list); region->age = 0; @@ -508,6 +509,7 @@ static void damon_update_monitoring_result(struct damon_region *r, { r->nr_accesses = damon_nr_accesses_for_new_attrs(r->nr_accesses, old_attrs, new_attrs); + r->nr_accesses_bp = r->nr_accesses * 10000; r->age = damon_age_for_new_attrs(r->age, old_attrs, new_attrs); } @@ -1115,6 +1117,7 @@ static void damon_merge_two_regions(struct damon_target *t, l->nr_accesses = (l->nr_accesses * sz_l + r->nr_accesses * sz_r) / (sz_l + sz_r); + l->nr_accesses_bp = l->nr_accesses * 10000; l->age = (l->age * sz_l + r->age * sz_r) / (sz_l + sz_r); l->ar.end = r->ar.end; damon_destroy_region(r, t); @@ -1138,6 +1141,8 @@ static void damon_merge_regions_of(struct damon_target *t, unsigned int thres, else r->age++; + r->nr_accesses_bp = r->nr_accesses * 10000; + if (prev && prev->ar.end == r->ar.start && abs(prev->nr_accesses - r->nr_accesses) <= thres && damon_sz_region(prev) + damon_sz_region(r) <= sz_limit) @@ -1186,6 +1191,7 @@ static void damon_split_region_at(struct damon_target *t, new->age = r->age; new->last_nr_accesses = r->last_nr_accesses; + new->nr_accesses_bp = r->nr_accesses_bp; damon_insert_region(new, r, damon_next_region(r), t); } -- cgit v1.2.3 From ace30fb21af5f1be1605db72c16040b95b1557ef Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 15 Sep 2023 02:52:49 +0000 Subject: mm/damon/core: use pseudo-moving sum for nr_accesses_bp Let nr_accesses_bp be calculated as a pseudo-moving sum that updated for every sampling interval, using damon_moving_sum(). This is assumed to be useful for cases that the aggregation interval is set quite huge, but the monivoting results need to be collected earlier than next aggregation interval is passed. Link: https://lkml.kernel.org/r/20230915025251.72816-7-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Signed-off-by: Andrew Morton --- include/linux/damon.h | 12 +++++++++--- mm/damon/core.c | 16 +++++++++++++++- mm/damon/paddr.c | 9 +++++---- mm/damon/vaddr.c | 12 +++++++----- 4 files changed, 36 insertions(+), 13 deletions(-) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index 15f24b23c9a0..0fe13482df63 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -40,7 +40,8 @@ struct damon_addr_range { * @ar: The address range of the region. * @sampling_addr: Address of the sample for the next access check. * @nr_accesses: Access frequency of this region. - * @nr_accesses_bp: @nr_accesses in basis point (0.01%). + * @nr_accesses_bp: @nr_accesses in basis point (0.01%) that updated for + * each sampling interval. * @list: List head for siblings. * @age: Age of this region. * @@ -51,7 +52,11 @@ struct damon_addr_range { * damon_update_region_access_rate(). * * @nr_accesses_bp is another representation of @nr_accesses in basis point - * (1 in 10,000) that updated every aggregation interval. + * (1 in 10,000) that updated for every &damon_attrs->sample_interval in a + * manner similar to moving sum. By the algorithm, this value becomes + * @nr_accesses * 10000 for every &struct damon_attrs->aggr_interval. This can + * be used when the aggregation interval is too huge and therefore cannot wait + * for it before getting the access monitoring results. * * @age is initially zero, increased for each aggregation interval, and reset * to zero again if the access frequency is significantly changed. If two @@ -629,7 +634,8 @@ int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges, unsigned int nr_ranges); unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum, unsigned int len_window, unsigned int new_value); -void damon_update_region_access_rate(struct damon_region *r, bool accessed); +void damon_update_region_access_rate(struct damon_region *r, bool accessed, + struct damon_attrs *attrs); struct damos_filter *damos_new_filter(enum damos_filter_type type, bool matching); diff --git a/mm/damon/core.c b/mm/damon/core.c index ce85c00b0a4c..29ee1fc18393 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1599,14 +1599,28 @@ unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum, * damon_update_region_access_rate() - Update the access rate of a region. * @r: The DAMON region to update for its access check result. * @accessed: Whether the region has accessed during last sampling interval. + * @attrs: The damon_attrs of the DAMON context. * * Update the access rate of a region with the region's last sampling interval * access check result. * * Usually this will be called by &damon_operations->check_accesses callback. */ -void damon_update_region_access_rate(struct damon_region *r, bool accessed) +void damon_update_region_access_rate(struct damon_region *r, bool accessed, + struct damon_attrs *attrs) { + unsigned int len_window = 1; + + /* + * sample_interval can be zero, but cannot be larger than + * aggr_interval, owing to validation of damon_set_attrs(). + */ + if (attrs->sample_interval) + len_window = attrs->aggr_interval / attrs->sample_interval; + r->nr_accesses_bp = damon_moving_sum(r->nr_accesses_bp, + r->last_nr_accesses * 10000, len_window, + accessed ? 10000 : 0); + if (accessed) r->nr_accesses++; } diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index 44f21860b555..081e2a325778 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -148,7 +148,8 @@ out: return accessed; } -static void __damon_pa_check_access(struct damon_region *r) +static void __damon_pa_check_access(struct damon_region *r, + struct damon_attrs *attrs) { static unsigned long last_addr; static unsigned long last_folio_sz = PAGE_SIZE; @@ -157,12 +158,12 @@ static void __damon_pa_check_access(struct damon_region *r) /* If the region is in the last checked page, reuse the result */ if (ALIGN_DOWN(last_addr, last_folio_sz) == ALIGN_DOWN(r->sampling_addr, last_folio_sz)) { - damon_update_region_access_rate(r, last_accessed); + damon_update_region_access_rate(r, last_accessed, attrs); return; } last_accessed = damon_pa_young(r->sampling_addr, &last_folio_sz); - damon_update_region_access_rate(r, last_accessed); + damon_update_region_access_rate(r, last_accessed, attrs); last_addr = r->sampling_addr; } @@ -175,7 +176,7 @@ static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx) damon_for_each_target(t, ctx) { damon_for_each_region(r, t) { - __damon_pa_check_access(r); + __damon_pa_check_access(r, &ctx->attrs); max_nr_accesses = max(r->nr_accesses, max_nr_accesses); } } diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c index 02ab448d9b1e..a4d1f63c5b23 100644 --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -558,26 +558,27 @@ static bool damon_va_young(struct mm_struct *mm, unsigned long addr, * r the region to be checked */ static void __damon_va_check_access(struct mm_struct *mm, - struct damon_region *r, bool same_target) + struct damon_region *r, bool same_target, + struct damon_attrs *attrs) { static unsigned long last_addr; static unsigned long last_folio_sz = PAGE_SIZE; static bool last_accessed; if (!mm) { - damon_update_region_access_rate(r, false); + damon_update_region_access_rate(r, false, attrs); return; } /* If the region is in the last checked page, reuse the result */ if (same_target && (ALIGN_DOWN(last_addr, last_folio_sz) == ALIGN_DOWN(r->sampling_addr, last_folio_sz))) { - damon_update_region_access_rate(r, last_accessed); + damon_update_region_access_rate(r, last_accessed, attrs); return; } last_accessed = damon_va_young(mm, r->sampling_addr, &last_folio_sz); - damon_update_region_access_rate(r, last_accessed); + damon_update_region_access_rate(r, last_accessed, attrs); last_addr = r->sampling_addr; } @@ -594,7 +595,8 @@ static unsigned int damon_va_check_accesses(struct damon_ctx *ctx) mm = damon_get_mm(t); same_target = false; damon_for_each_region(r, t) { - __damon_va_check_access(mm, r, same_target); + __damon_va_check_access(mm, r, same_target, + &ctx->attrs); max_nr_accesses = max(r->nr_accesses, max_nr_accesses); same_target = true; } -- cgit v1.2.3 From 863803a7948c8e33e6a7b002017747ca83ecfd63 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 15 Sep 2023 02:52:51 +0000 Subject: mm/damon/core: mark damon_moving_sum() as a static function The function is used by only mm/damon/core.c. Mark it as a static function. Link: https://lkml.kernel.org/r/20230915025251.72816-9-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Signed-off-by: Andrew Morton --- include/linux/damon.h | 2 -- mm/damon/core.c | 2 +- 2 files changed, 1 insertion(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index 0fe13482df63..491fdd3e4c76 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -632,8 +632,6 @@ void damon_add_region(struct damon_region *r, struct damon_target *t); void damon_destroy_region(struct damon_region *r, struct damon_target *t); int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges, unsigned int nr_ranges); -unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum, - unsigned int len_window, unsigned int new_value); void damon_update_region_access_rate(struct damon_region *r, bool accessed, struct damon_attrs *attrs); diff --git a/mm/damon/core.c b/mm/damon/core.c index 45cc108c0fe1..b15cf47d2d29 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1587,7 +1587,7 @@ int damon_set_region_biggest_system_ram_default(struct damon_target *t, * * Return: Pseudo-moving average after getting the @new_value. */ -unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum, +static unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum, unsigned int len_window, unsigned int new_value) { return mvsum - nomvsum / len_window + new_value; -- cgit v1.2.3 From 77e6c43e137c130138c3fbadc847351a83c4befe Mon Sep 17 00:00:00 2001 From: Usama Arif Date: Wed, 13 Sep 2023 11:54:00 +0100 Subject: memblock: introduce MEMBLOCK_RSRV_NOINIT flag For reserved memory regions marked with this flag, reserve_bootmem_region is not called during memmap_init_reserved_pages. This can be used to avoid struct page initialization for regions which won't need them, for e.g. hugepages with Hugepage Vmemmap Optimization enabled. Link: https://lkml.kernel.org/r/20230913105401.519709-4-usama.arif@bytedance.com Signed-off-by: Usama Arif Acked-by: Muchun Song Reviewed-by: Mike Rapoport (IBM) Cc: Fam Zheng Cc: Mike Kravetz Cc: Punit Agrawal Signed-off-by: Andrew Morton --- include/linux/memblock.h | 9 +++++++++ mm/memblock.c | 33 ++++++++++++++++++++++++++++----- 2 files changed, 37 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/memblock.h b/include/linux/memblock.h index 1c1072e3ca06..ae3bde302f70 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -40,6 +40,8 @@ extern unsigned long long max_possible_pfn; * via a driver, and never indicated in the firmware-provided memory map as * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in the * kernel resource tree. + * @MEMBLOCK_RSRV_NOINIT: memory region for which struct pages are + * not initialized (only for reserved regions). */ enum memblock_flags { MEMBLOCK_NONE = 0x0, /* No special request */ @@ -47,6 +49,7 @@ enum memblock_flags { MEMBLOCK_MIRROR = 0x2, /* mirrored region */ MEMBLOCK_NOMAP = 0x4, /* don't add to kernel direct mapping */ MEMBLOCK_DRIVER_MANAGED = 0x8, /* always detected via a driver */ + MEMBLOCK_RSRV_NOINIT = 0x10, /* don't initialize struct pages */ }; /** @@ -125,6 +128,7 @@ int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); int memblock_mark_nomap(phys_addr_t base, phys_addr_t size); int memblock_clear_nomap(phys_addr_t base, phys_addr_t size); +int memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size); void memblock_free_all(void); void memblock_free(void *ptr, size_t size); @@ -259,6 +263,11 @@ static inline bool memblock_is_nomap(struct memblock_region *m) return m->flags & MEMBLOCK_NOMAP; } +static inline bool memblock_is_reserved_noinit(struct memblock_region *m) +{ + return m->flags & MEMBLOCK_RSRV_NOINIT; +} + static inline bool memblock_is_driver_managed(struct memblock_region *m) { return m->flags & MEMBLOCK_DRIVER_MANAGED; diff --git a/mm/memblock.c b/mm/memblock.c index b978cda96cf0..fd492e5bbdbc 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -997,6 +997,24 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size) return memblock_setclr_flag(&memblock.memory, base, size, 0, MEMBLOCK_NOMAP); } +/** + * memblock_reserved_mark_noinit - Mark a reserved memory region with flag + * MEMBLOCK_RSRV_NOINIT which results in the struct pages not being initialized + * for this region. + * @base: the base phys addr of the region + * @size: the size of the region + * + * struct pages will not be initialized for reserved memory regions marked with + * %MEMBLOCK_RSRV_NOINIT. + * + * Return: 0 on success, -errno on failure. + */ +int __init_memblock memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size) +{ + return memblock_setclr_flag(&memblock.reserved, base, size, 1, + MEMBLOCK_RSRV_NOINIT); +} + static bool should_skip_region(struct memblock_type *type, struct memblock_region *m, int nid, int flags) @@ -2113,13 +2131,18 @@ static void __init memmap_init_reserved_pages(void) memblock_set_node(start, end, &memblock.reserved, nid); } - /* initialize struct pages for the reserved regions */ + /* + * initialize struct pages for reserved regions that don't have + * the MEMBLOCK_RSRV_NOINIT flag set + */ for_each_reserved_mem_region(region) { - nid = memblock_get_region_node(region); - start = region->base; - end = start + region->size; + if (!memblock_is_reserved_noinit(region)) { + nid = memblock_get_region_node(region); + start = region->base; + end = start + region->size; - reserve_bootmem_region(start, end, nid); + reserve_bootmem_region(start, end, nid); + } } } -- cgit v1.2.3 From 42f994b71404b17abcd6b170de7a6aa95ffe5d4a Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Sat, 16 Sep 2023 02:09:40 +0000 Subject: mm/damon/core: implement scheme-specific apply interval DAMON-based operation schemes are applied for every aggregation interval. That was mainly because schemes were using nr_accesses, which be complete to be used for every aggregation interval. However, the schemes are now using nr_accesses_bp, which is updated for each sampling interval in a way that reasonable to be used. Therefore, there is no reason to apply schemes for each aggregation interval. The unnecessary alignment with aggregation interval was also making some use cases of DAMOS tricky. Quotas setting under long aggregation interval is one such example. Suppose the aggregation interval is ten seconds, and there is a scheme having CPU quota 100ms per 1s. The scheme will actually uses 100ms per ten seconds, since it cannobe be applied before next aggregation interval. The feature is working as intended, but the results might not that intuitive for some users. This could be fixed by updating the quota to 1s per 10s. But, in the case, the CPU usage of DAMOS could look like spikes, and would actually make a bad effect to other CPU-sensitive workloads. Implement a dedicated timing interval for each DAMON-based operation scheme, namely apply_interval. The interval will be sampling interval aligned, and each scheme will be applied for its apply_interval. The interval is set to 0 by default, and it means the scheme should use the aggregation interval instead. This avoids old users getting any behavioral difference. Link: https://lkml.kernel.org/r/20230916020945.47296-5-sj@kernel.org Signed-off-by: SeongJae Park Cc: Jonathan Corbet Cc: Shuah Khan Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton --- include/linux/damon.h | 17 ++++++++++-- mm/damon/core.c | 72 +++++++++++++++++++++++++++++++++++++++++++----- mm/damon/dbgfs.c | 3 +- mm/damon/lru_sort.c | 2 ++ mm/damon/reclaim.c | 2 ++ mm/damon/sysfs-schemes.c | 2 +- 6 files changed, 87 insertions(+), 11 deletions(-) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index 491fdd3e4c76..27b995c22497 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -314,16 +314,19 @@ struct damos_access_pattern { * struct damos - Represents a Data Access Monitoring-based Operation Scheme. * @pattern: Access pattern of target regions. * @action: &damo_action to be applied to the target regions. + * @apply_interval_us: The time between applying the @action. * @quota: Control the aggressiveness of this scheme. * @wmarks: Watermarks for automated (in)activation of this scheme. * @filters: Additional set of &struct damos_filter for &action. * @stat: Statistics of this scheme. * @list: List head for siblings. * - * For each aggregation interval, DAMON finds regions which fit in the + * For each @apply_interval_us, DAMON finds regions which fit in the * &pattern and applies &action to those. To avoid consuming too much * CPU time or IO resources for the &action, "a is used. * + * If @apply_interval_us is zero, &damon_attrs->aggr_interval is used instead. + * * To do the work only when needed, schemes can be activated for specific * system situations using &wmarks. If all schemes that registered to the * monitoring context are inactive, DAMON stops monitoring either, and just @@ -340,6 +343,14 @@ struct damos_access_pattern { struct damos { struct damos_access_pattern pattern; enum damos_action action; + unsigned long apply_interval_us; +/* private: internal use only */ + /* + * number of sample intervals that should be passed before applying + * @action + */ + unsigned long next_apply_sis; +/* public: */ struct damos_quota quota; struct damos_watermarks wmarks; struct list_head filters; @@ -641,7 +652,9 @@ void damos_add_filter(struct damos *s, struct damos_filter *f); void damos_destroy_filter(struct damos_filter *f); struct damos *damon_new_scheme(struct damos_access_pattern *pattern, - enum damos_action action, struct damos_quota *quota, + enum damos_action action, + unsigned long apply_interval_us, + struct damos_quota *quota, struct damos_watermarks *wmarks); void damon_add_scheme(struct damon_ctx *ctx, struct damos *s); void damon_destroy_scheme(struct damos *s); diff --git a/mm/damon/core.c b/mm/damon/core.c index 79fef5145a4b..5eb649bd002f 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -313,7 +313,9 @@ static struct damos_quota *damos_quota_init_priv(struct damos_quota *quota) } struct damos *damon_new_scheme(struct damos_access_pattern *pattern, - enum damos_action action, struct damos_quota *quota, + enum damos_action action, + unsigned long apply_interval_us, + struct damos_quota *quota, struct damos_watermarks *wmarks) { struct damos *scheme; @@ -323,6 +325,13 @@ struct damos *damon_new_scheme(struct damos_access_pattern *pattern, return NULL; scheme->pattern = *pattern; scheme->action = action; + scheme->apply_interval_us = apply_interval_us; + /* + * next_apply_sis will be set when kdamond starts. While kdamond is + * running, it will also updated when it is added to the DAMON context, + * or damon_attrs are updated. + */ + scheme->next_apply_sis = 0; INIT_LIST_HEAD(&scheme->filters); scheme->stat = (struct damos_stat){}; INIT_LIST_HEAD(&scheme->list); @@ -335,9 +344,21 @@ struct damos *damon_new_scheme(struct damos_access_pattern *pattern, return scheme; } +static void damos_set_next_apply_sis(struct damos *s, struct damon_ctx *ctx) +{ + unsigned long sample_interval = ctx->attrs.sample_interval ? + ctx->attrs.sample_interval : 1; + unsigned long apply_interval = s->apply_interval_us ? + s->apply_interval_us : ctx->attrs.aggr_interval; + + s->next_apply_sis = ctx->passed_sample_intervals + + apply_interval / sample_interval; +} + void damon_add_scheme(struct damon_ctx *ctx, struct damos *s) { list_add_tail(&s->list, &ctx->schemes); + damos_set_next_apply_sis(s, ctx); } static void damon_del_scheme(struct damos *s) @@ -558,6 +579,7 @@ int damon_set_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs) { unsigned long sample_interval = attrs->sample_interval ? attrs->sample_interval : 1; + struct damos *s; if (attrs->min_nr_regions < 3) return -EINVAL; @@ -573,6 +595,10 @@ int damon_set_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs) damon_update_monitoring_results(ctx, attrs); ctx->attrs = *attrs; + + damon_for_each_scheme(s, ctx) + damos_set_next_apply_sis(s, ctx); + return 0; } @@ -1094,14 +1120,29 @@ static void kdamond_apply_schemes(struct damon_ctx *c) struct damon_target *t; struct damon_region *r, *next_r; struct damos *s; + unsigned long sample_interval = c->attrs.sample_interval ? + c->attrs.sample_interval : 1; + bool has_schemes_to_apply = false; damon_for_each_scheme(s, c) { + if (c->passed_sample_intervals != s->next_apply_sis) + continue; + + s->next_apply_sis += + (s->apply_interval_us ? s->apply_interval_us : + c->attrs.aggr_interval) / sample_interval; + if (!s->wmarks.activated) continue; + has_schemes_to_apply = true; + damos_adjust_quota(c, s); } + if (!has_schemes_to_apply) + return; + damon_for_each_target(t, c) { damon_for_each_region_safe(r, next_r, t) damon_do_apply_schemes(c, t, r); @@ -1372,11 +1413,19 @@ static void kdamond_init_intervals_sis(struct damon_ctx *ctx) { unsigned long sample_interval = ctx->attrs.sample_interval ? ctx->attrs.sample_interval : 1; + unsigned long apply_interval; + struct damos *scheme; ctx->passed_sample_intervals = 0; ctx->next_aggregation_sis = ctx->attrs.aggr_interval / sample_interval; ctx->next_ops_update_sis = ctx->attrs.ops_update_interval / sample_interval; + + damon_for_each_scheme(scheme, ctx) { + apply_interval = scheme->apply_interval_us ? + scheme->apply_interval_us : ctx->attrs.aggr_interval; + scheme->next_apply_sis = apply_interval / sample_interval; + } } /* @@ -1428,19 +1477,28 @@ static int kdamond_fn(void *data) if (ctx->ops.check_accesses) max_nr_accesses = ctx->ops.check_accesses(ctx); - sample_interval = ctx->attrs.sample_interval ? - ctx->attrs.sample_interval : 1; if (ctx->passed_sample_intervals == next_aggregation_sis) { - ctx->next_aggregation_sis = next_aggregation_sis + - ctx->attrs.aggr_interval / sample_interval; kdamond_merge_regions(ctx, max_nr_accesses / 10, sz_limit); if (ctx->callback.after_aggregation && ctx->callback.after_aggregation(ctx)) break; - if (!list_empty(&ctx->schemes)) - kdamond_apply_schemes(ctx); + } + + /* + * do kdamond_apply_schemes() after kdamond_merge_regions() if + * possible, to reduce overhead + */ + if (!list_empty(&ctx->schemes)) + kdamond_apply_schemes(ctx); + + sample_interval = ctx->attrs.sample_interval ? + ctx->attrs.sample_interval : 1; + if (ctx->passed_sample_intervals == next_aggregation_sis) { + ctx->next_aggregation_sis = next_aggregation_sis + + ctx->attrs.aggr_interval / sample_interval; + kdamond_reset_aggregated(ctx); kdamond_split_regions(ctx); if (ctx->ops.reset_aggregated) diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index 124f0f8c97b7..dc0ea1fc30ca 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -278,7 +278,8 @@ static struct damos **str_to_schemes(const char *str, ssize_t len, goto fail; pos += parsed; - scheme = damon_new_scheme(&pattern, action, "a, &wmarks); + scheme = damon_new_scheme(&pattern, action, 0, "a, + &wmarks); if (!scheme) goto fail; diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c index 7b8fce2f67a8..3ecdcc029443 100644 --- a/mm/damon/lru_sort.c +++ b/mm/damon/lru_sort.c @@ -158,6 +158,8 @@ static struct damos *damon_lru_sort_new_scheme( pattern, /* (de)prioritize on LRU-lists */ action, + /* for each aggregation interval */ + 0, /* under the quota. */ "a, /* (De)activate this according to the watermarks. */ diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c index 648d2a85523a..ab974e477d2f 100644 --- a/mm/damon/reclaim.c +++ b/mm/damon/reclaim.c @@ -142,6 +142,8 @@ static struct damos *damon_reclaim_new_scheme(void) &pattern, /* page out those, as soon as found */ DAMOS_PAGEOUT, + /* for each aggregation interval */ + 0, /* under the quota. */ &damon_reclaim_quota, /* (De)activate this according to the watermarks. */ diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c index 093700f50b18..3d30e85596b0 100644 --- a/mm/damon/sysfs-schemes.c +++ b/mm/damon/sysfs-schemes.c @@ -1610,7 +1610,7 @@ static struct damos *damon_sysfs_mk_scheme( .low = sysfs_wmarks->low, }; - scheme = damon_new_scheme(&pattern, sysfs_scheme->action, "a, + scheme = damon_new_scheme(&pattern, sysfs_scheme->action, 0, "a, &wmarks); if (!scheme) return NULL; -- cgit v1.2.3 From 51a23b1be92046f0cc52384d30cf060700f1a54e Mon Sep 17 00:00:00 2001 From: Li Zhijian Date: Wed, 2 Aug 2023 17:28:56 +0800 Subject: acpi,mm: fix typo sibiling -> sibling First found this typo as reviewing memory tier code. Fix it by sed like: $ sed -i 's/sibiling/sibling/g' $(git grep -l sibiling) so the acpi one will be corrected as well. Link: https://lkml.kernel.org/r/20230802092856.819328-1-lizhijian@cn.fujitsu.com Signed-off-by: Li Zhijian Cc: Aneesh Kumar K.V Cc: Huang, Ying Cc: Len Brown Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton --- drivers/acpi/acpi_pad.c | 2 +- include/linux/memory-tiers.h | 2 +- mm/memory-tiers.c | 10 +++++----- 3 files changed, 7 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c index 7a453c5ff303..7f073ca64f0e 100644 --- a/drivers/acpi/acpi_pad.c +++ b/drivers/acpi/acpi_pad.c @@ -100,7 +100,7 @@ static void round_robin_cpu(unsigned int tsk_index) for_each_cpu(cpu, pad_busy_cpus) cpumask_or(tmp, tmp, topology_sibling_cpumask(cpu)); cpumask_andnot(tmp, cpu_online_mask, tmp); - /* avoid HT sibilings if possible */ + /* avoid HT siblings if possible */ if (cpumask_empty(tmp)) cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus); if (cpumask_empty(tmp)) { diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index 437441cdf78f..4fa178b50784 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -22,7 +22,7 @@ struct memory_tier; struct memory_dev_type { /* list of memory types that are part of same tier as this type */ - struct list_head tier_sibiling; + struct list_head tier_sibling; /* abstract distance for this specific memory type */ int adistance; /* Nodes of same abstract distance */ diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index 37a4f59d9585..876d8a5e210e 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -115,7 +115,7 @@ static __always_inline nodemask_t get_memtier_nodemask(struct memory_tier *memti nodemask_t nodes = NODE_MASK_NONE; struct memory_dev_type *memtype; - list_for_each_entry(memtype, &memtier->memory_types, tier_sibiling) + list_for_each_entry(memtype, &memtier->memory_types, tier_sibling) nodes_or(nodes, nodes, memtype->nodes); return nodes; @@ -174,7 +174,7 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty * If the memtype is already part of a memory tier, * just return that. */ - if (!list_empty(&memtype->tier_sibiling)) { + if (!list_empty(&memtype->tier_sibling)) { list_for_each_entry(memtier, &memory_tiers, list) { if (adistance == memtier->adistance_start) return memtier; @@ -218,7 +218,7 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty memtier = new_memtier; link_memtype: - list_add(&memtype->tier_sibiling, &memtier->memory_types); + list_add(&memtype->tier_sibling, &memtier->memory_types); return memtier; } @@ -527,7 +527,7 @@ static bool clear_node_memory_tier(int node) memtype = node_memory_types[node].memtype; node_clear(node, memtype->nodes); if (nodes_empty(memtype->nodes)) { - list_del_init(&memtype->tier_sibiling); + list_del_init(&memtype->tier_sibling); if (list_empty(&memtier->memory_types)) destroy_memory_tier(memtier); } @@ -553,7 +553,7 @@ struct memory_dev_type *alloc_memory_type(int adistance) return ERR_PTR(-ENOMEM); memtype->adistance = adistance; - INIT_LIST_HEAD(&memtype->tier_sibiling); + INIT_LIST_HEAD(&memtype->tier_sibling); memtype->nodes = NODE_MASK_NONE; kref_init(&memtype->kref); return memtype; -- cgit v1.2.3 From 55d2a0bd5eadaade850efa9d3a7ffbb0aeb67198 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Mon, 18 Sep 2023 14:31:42 +0800 Subject: mm: add statistics for PUD level pagetable Recently, we found that cross-die access to pagetable pages on ARM64 machines can cause performance fluctuations in our business. Currently, there are no PMU events available to track this situation on our ARM64 machines, so accurate pagetable accounting can help to analyze this issue, but now the PUD level pagetable accounting is missed. So introduce pagetable_pud_ctor/dtor() to help to get accurate PUD pagetable accounting, as well as converting the architectures which use generic PUD pagetable allocation to add corresponding PUD pagetable accounting. Moreover this patch will mark the PUD level pagetable with PG_table flag, which will help to do sanity validation in unpoison_memory(). On my testing machine, I can see more pagetables statistics after the patch with page-types tool: Before patch: flags page-count MB symbolic-flags long-symbolic-flags 0x0000000004000000 27326 106 __________________________g_________________ pgtable After patch: 0x0000000004000000 27541 107 __________________________g_________________ pgtable Link: https://lkml.kernel.org/r/876c71c03a7e69c17722a690e3225a4f7b172fb2.1695017383.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: Mike Rapoport (IBM) Acked-by: Vishal Moola (Oracle) Cc: Andy Lutomirski Cc: Aneesh Kumar K.V Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Catalin Marinas Cc: Dave Hansen Cc: Huacai Chen Cc: Ingo Molnar Cc: Matthew Wilcox (Oracle) Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/arm64/include/asm/tlb.h | 5 ++++- arch/loongarch/include/asm/pgalloc.h | 1 + arch/mips/include/asm/pgalloc.h | 1 + arch/x86/mm/pgtable.c | 3 +++ include/asm-generic/pgalloc.h | 7 ++++++- include/linux/mm.h | 16 ++++++++++++++++ 6 files changed, 31 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h index 2c29239d05c3..846c563689a8 100644 --- a/arch/arm64/include/asm/tlb.h +++ b/arch/arm64/include/asm/tlb.h @@ -96,7 +96,10 @@ static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pudp, unsigned long addr) { - tlb_remove_ptdesc(tlb, virt_to_ptdesc(pudp)); + struct ptdesc *ptdesc = virt_to_ptdesc(pudp); + + pagetable_pud_dtor(ptdesc); + tlb_remove_ptdesc(tlb, ptdesc); } #endif diff --git a/arch/loongarch/include/asm/pgalloc.h b/arch/loongarch/include/asm/pgalloc.h index 79470f0b4f1d..4e2d6b7ca2ee 100644 --- a/arch/loongarch/include/asm/pgalloc.h +++ b/arch/loongarch/include/asm/pgalloc.h @@ -84,6 +84,7 @@ static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address) if (!ptdesc) return NULL; + pagetable_pud_ctor(ptdesc); pud = ptdesc_address(ptdesc); pud_init(pud); diff --git a/arch/mips/include/asm/pgalloc.h b/arch/mips/include/asm/pgalloc.h index 40e40a7eb94a..f4440edcd8fe 100644 --- a/arch/mips/include/asm/pgalloc.h +++ b/arch/mips/include/asm/pgalloc.h @@ -95,6 +95,7 @@ static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address) if (!ptdesc) return NULL; + pagetable_pud_ctor(ptdesc); pud = ptdesc_address(ptdesc); pud_init(pud); diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 9deadf517f14..0cbc1b8e8e3d 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -76,6 +76,9 @@ void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd) #if CONFIG_PGTABLE_LEVELS > 3 void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud) { + struct ptdesc *ptdesc = virt_to_ptdesc(pud); + + pagetable_pud_dtor(ptdesc); paravirt_release_pud(__pa(pud) >> PAGE_SHIFT); paravirt_tlb_remove_table(tlb, virt_to_page(pud)); } diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h index c75d4a753849..879e5f8aa5e9 100644 --- a/include/asm-generic/pgalloc.h +++ b/include/asm-generic/pgalloc.h @@ -169,6 +169,8 @@ static inline pud_t *__pud_alloc_one(struct mm_struct *mm, unsigned long addr) ptdesc = pagetable_alloc(gfp, 0); if (!ptdesc) return NULL; + + pagetable_pud_ctor(ptdesc); return ptdesc_address(ptdesc); } @@ -190,8 +192,11 @@ static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr) static inline void __pud_free(struct mm_struct *mm, pud_t *pud) { + struct ptdesc *ptdesc = virt_to_ptdesc(pud); + BUG_ON((unsigned long)pud & (PAGE_SIZE-1)); - pagetable_free(virt_to_ptdesc(pud)); + pagetable_pud_dtor(ptdesc); + pagetable_free(ptdesc); } #ifndef __HAVE_ARCH_PUD_FREE diff --git a/include/linux/mm.h b/include/linux/mm.h index 31dc25d3f6b5..126b54b45442 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3049,6 +3049,22 @@ static inline spinlock_t *pud_lock(struct mm_struct *mm, pud_t *pud) return ptl; } +static inline void pagetable_pud_ctor(struct ptdesc *ptdesc) +{ + struct folio *folio = ptdesc_folio(ptdesc); + + __folio_set_pgtable(folio); + lruvec_stat_add_folio(folio, NR_PAGETABLE); +} + +static inline void pagetable_pud_dtor(struct ptdesc *ptdesc) +{ + struct folio *folio = ptdesc_folio(ptdesc); + + __folio_clear_pgtable(folio); + lruvec_stat_sub_folio(folio, NR_PAGETABLE); +} + extern void __init pagecache_init(void); extern void free_initmem(void); -- cgit v1.2.3 From 7ced098fcfe596feab3cea4f40128b0119c7bf1a Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Mon, 18 Sep 2023 22:18:32 +0200 Subject: mm: document mmu_notifier_invalidate_range_start_nonblock() Document what mmu_notifier_invalidate_range_start_nonblock() is for. Also add a __must_check annotation to signal that callers must bail out if a notifier vetoes the operation. Link: https://lkml.kernel.org/r/20230918201832.265108-1-jannh@google.com Signed-off-by: Jann Horn Reviewed-by: Jason Gunthorpe Reviewed-by: Alistair Popple Signed-off-by: Andrew Morton --- include/linux/mmu_notifier.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index 6e3c857606f1..f349e08a9dfe 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -459,7 +459,14 @@ mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range) lock_map_release(&__mmu_notifier_invalidate_range_start_map); } -static inline int +/* + * This version of mmu_notifier_invalidate_range_start() avoids blocking, but it + * can return an error if a notifier can't proceed without blocking, in which + * case you're not allowed to modify PTEs in the specified range. + * + * This is mainly intended for OOM handling. + */ +static inline int __must_check mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range) { int ret = 0; -- cgit v1.2.3 From 24e41bf8a6b424c76c5902fb999e9eca61bdf83d Mon Sep 17 00:00:00 2001 From: Florent Revest Date: Mon, 28 Aug 2023 17:08:57 +0200 Subject: mm: add a NO_INHERIT flag to the PR_SET_MDWE prctl This extends the current PR_SET_MDWE prctl arg with a bit to indicate that the process doesn't want MDWE protection to propagate to children. To implement this no-inherit mode, the tag in current->mm->flags must be absent from MMF_INIT_MASK. This means that the encoding for "MDWE but without inherit" is different in the prctl than in the mm flags. This leads to a bit of bit-mangling in the prctl implementation. Link: https://lkml.kernel.org/r/20230828150858.393570-6-revest@chromium.org Signed-off-by: Florent Revest Reviewed-by: Kees Cook Reviewed-by: Catalin Marinas Cc: Alexey Izbyshev Cc: Anshuman Khandual Cc: Ayush Jain Cc: David Hildenbrand Cc: Greg Thelen Cc: Joey Gouly Cc: KP Singh Cc: Mark Brown Cc: Michal Hocko Cc: Peter Xu Cc: Ryan Roberts Cc: Szabolcs Nagy Cc: Topi Miettinen Signed-off-by: Andrew Morton --- include/linux/sched/coredump.h | 10 ++++++++++ include/uapi/linux/prctl.h | 1 + kernel/fork.c | 2 +- kernel/sys.c | 32 ++++++++++++++++++++++++++------ tools/include/uapi/linux/prctl.h | 1 + 5 files changed, 39 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h index 0ee96ea7a0e9..1b37fa8fc723 100644 --- a/include/linux/sched/coredump.h +++ b/include/linux/sched/coredump.h @@ -91,4 +91,14 @@ static inline int get_dumpable(struct mm_struct *mm) MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK) #define MMF_VM_MERGE_ANY 29 +#define MMF_HAS_MDWE_NO_INHERIT 30 + +static inline unsigned long mmf_init_flags(unsigned long flags) +{ + if (flags & (1UL << MMF_HAS_MDWE_NO_INHERIT)) + flags &= ~((1UL << MMF_HAS_MDWE) | + (1UL << MMF_HAS_MDWE_NO_INHERIT)); + return flags & MMF_INIT_MASK; +} + #endif /* _LINUX_SCHED_COREDUMP_H */ diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 9a85c69782bd..370ed14b1ae0 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -284,6 +284,7 @@ struct prctl_mm_map { /* Memory deny write / execute */ #define PR_SET_MDWE 65 # define PR_MDWE_REFUSE_EXEC_GAIN (1UL << 0) +# define PR_MDWE_NO_INHERIT (1UL << 1) #define PR_GET_MDWE 66 diff --git a/kernel/fork.c b/kernel/fork.c index 1779183a7cb3..e45a4457ba83 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1288,7 +1288,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, hugetlb_count_init(mm); if (current->mm) { - mm->flags = current->mm->flags & MMF_INIT_MASK; + mm->flags = mmf_init_flags(current->mm->flags); mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK; } else { mm->flags = default_dump_filter; diff --git a/kernel/sys.c b/kernel/sys.c index 2410e3999ebe..4a8073c1b255 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2368,19 +2368,41 @@ static int prctl_set_vma(unsigned long opt, unsigned long start, } #endif /* CONFIG_ANON_VMA_NAME */ +static inline unsigned long get_current_mdwe(void) +{ + unsigned long ret = 0; + + if (test_bit(MMF_HAS_MDWE, ¤t->mm->flags)) + ret |= PR_MDWE_REFUSE_EXEC_GAIN; + if (test_bit(MMF_HAS_MDWE_NO_INHERIT, ¤t->mm->flags)) + ret |= PR_MDWE_NO_INHERIT; + + return ret; +} + static inline int prctl_set_mdwe(unsigned long bits, unsigned long arg3, unsigned long arg4, unsigned long arg5) { + unsigned long current_bits; + if (arg3 || arg4 || arg5) return -EINVAL; - if (bits & ~(PR_MDWE_REFUSE_EXEC_GAIN)) + if (bits & ~(PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT)) + return -EINVAL; + + /* NO_INHERIT only makes sense with REFUSE_EXEC_GAIN */ + if (bits & PR_MDWE_NO_INHERIT && !(bits & PR_MDWE_REFUSE_EXEC_GAIN)) return -EINVAL; + current_bits = get_current_mdwe(); + if (current_bits && current_bits != bits) + return -EPERM; /* Cannot unset the flags */ + + if (bits & PR_MDWE_NO_INHERIT) + set_bit(MMF_HAS_MDWE_NO_INHERIT, ¤t->mm->flags); if (bits & PR_MDWE_REFUSE_EXEC_GAIN) set_bit(MMF_HAS_MDWE, ¤t->mm->flags); - else if (test_bit(MMF_HAS_MDWE, ¤t->mm->flags)) - return -EPERM; /* Cannot unset the flag */ return 0; } @@ -2390,9 +2412,7 @@ static inline int prctl_get_mdwe(unsigned long arg2, unsigned long arg3, { if (arg2 || arg3 || arg4 || arg5) return -EINVAL; - - return test_bit(MMF_HAS_MDWE, ¤t->mm->flags) ? - PR_MDWE_REFUSE_EXEC_GAIN : 0; + return get_current_mdwe(); } static int prctl_get_auxv(void __user *addr, unsigned long len) diff --git a/tools/include/uapi/linux/prctl.h b/tools/include/uapi/linux/prctl.h index 9a85c69782bd..370ed14b1ae0 100644 --- a/tools/include/uapi/linux/prctl.h +++ b/tools/include/uapi/linux/prctl.h @@ -284,6 +284,7 @@ struct prctl_mm_map { /* Memory deny write / execute */ #define PR_SET_MDWE 65 # define PR_MDWE_REFUSE_EXEC_GAIN (1UL << 0) +# define PR_MDWE_NO_INHERIT (1UL << 1) #define PR_GET_MDWE 66 -- cgit v1.2.3 From 65610453459f9048678a0daef89d592e412ec00a Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Thu, 21 Sep 2023 15:44:12 +0800 Subject: mm: memory: add vm_normal_folio_pmd() Patch series "mm: convert numa balancing functions to use a folio", v2. do_numa_pages() only handles non-compound pages, and only PMD-mapped THPs are handled in do_huge_pmd_numa_page(). But a large, PTE-mapped folio will be supported so let's convert more numa balancing functions to use/take a folio in preparation for that, no functional change intended for now. This patch (of 6): The new vm_normal_folio_pmd() wrapper is similar to vm_normal_folio(), which allow them to completely replace the struct page variables with struct folio variables. Link: https://lkml.kernel.org/r/20230921074417.24004-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20230921074417.24004-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mm.h | 2 ++ mm/memory.c | 10 ++++++++++ 2 files changed, 12 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 126b54b45442..52c40b3d0813 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2327,6 +2327,8 @@ struct folio *vm_normal_folio(struct vm_area_struct *vma, unsigned long addr, pte_t pte); struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte); +struct folio *vm_normal_folio_pmd(struct vm_area_struct *vma, + unsigned long addr, pmd_t pmd); struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t pmd); diff --git a/mm/memory.c b/mm/memory.c index d956b231e835..311e862c6404 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -689,6 +689,16 @@ struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, out: return pfn_to_page(pfn); } + +struct folio *vm_normal_folio_pmd(struct vm_area_struct *vma, + unsigned long addr, pmd_t pmd) +{ + struct page *page = vm_normal_page_pmd(vma, addr, pmd); + + if (page) + return page_folio(page); + return NULL; +} #endif static void restore_exclusive_pte(struct vm_area_struct *vma, -- cgit v1.2.3 From 75c70128a67311070115b90d826a229d4bbbb2b5 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Thu, 21 Sep 2023 15:44:16 +0800 Subject: mm: mempolicy: make mpol_misplaced() to take a folio In preparation for large folio numa balancing, make mpol_misplaced() to take a folio, no functional change intended. Link: https://lkml.kernel.org/r/20230921074417.24004-6-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mempolicy.h | 5 +++-- mm/memory.c | 2 +- mm/mempolicy.c | 22 ++++++++++++---------- 3 files changed, 16 insertions(+), 13 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index d232de7cdc56..6c2754d7bfed 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -174,7 +174,7 @@ extern void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol); /* Check if a vma is migratable */ extern bool vma_migratable(struct vm_area_struct *vma); -extern int mpol_misplaced(struct page *, struct vm_area_struct *, unsigned long); +int mpol_misplaced(struct folio *, struct vm_area_struct *, unsigned long); extern void mpol_put_task_policy(struct task_struct *); static inline bool mpol_is_preferred_many(struct mempolicy *pol) @@ -278,7 +278,8 @@ static inline int mpol_parse_str(char *str, struct mempolicy **mpol) } #endif -static inline int mpol_misplaced(struct page *page, struct vm_area_struct *vma, +static inline int mpol_misplaced(struct folio *folio, + struct vm_area_struct *vma, unsigned long address) { return -1; /* no node preference */ diff --git a/mm/memory.c b/mm/memory.c index 20b290c9dc87..7ca16ed67634 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4738,7 +4738,7 @@ int numa_migrate_prep(struct folio *folio, struct vm_area_struct *vma, *flags |= TNF_FAULT_LOCAL; } - return mpol_misplaced(&folio->page, vma, addr); + return mpol_misplaced(folio, vma, addr); } static vm_fault_t do_numa_page(struct vm_fault *vmf) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index f1b00d6ac7ee..69c0eac7292c 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2564,24 +2564,25 @@ static void sp_free(struct sp_node *n) } /** - * mpol_misplaced - check whether current page node is valid in policy + * mpol_misplaced - check whether current folio node is valid in policy * - * @page: page to be checked - * @vma: vm area where page mapped - * @addr: virtual address where page mapped + * @folio: folio to be checked + * @vma: vm area where folio mapped + * @addr: virtual address in @vma for shared policy lookup and interleave policy * - * Lookup current policy node id for vma,addr and "compare to" page's + * Lookup current policy node id for vma,addr and "compare to" folio's * node id. Policy determination "mimics" alloc_page_vma(). * Called from fault path where we know the vma and faulting address. * * Return: NUMA_NO_NODE if the page is in a node that is valid for this - * policy, or a suitable node ID to allocate a replacement page from. + * policy, or a suitable node ID to allocate a replacement folio from. */ -int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr) +int mpol_misplaced(struct folio *folio, struct vm_area_struct *vma, + unsigned long addr) { struct mempolicy *pol; struct zoneref *z; - int curnid = page_to_nid(page); + int curnid = folio_nid(folio); unsigned long pgoff; int thiscpu = raw_smp_processor_id(); int thisnid = cpu_to_node(thiscpu); @@ -2637,11 +2638,12 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long BUG(); } - /* Migrate the page towards the node whose CPU is referencing it */ + /* Migrate the folio towards the node whose CPU is referencing it */ if (pol->flags & MPOL_F_MORON) { polnid = thisnid; - if (!should_numa_migrate_memory(current, page, curnid, thiscpu)) + if (!should_numa_migrate_memory(current, &folio->page, curnid, + thiscpu)) goto out; } -- cgit v1.2.3 From 8c9ae56dc73b5ae48a14000b96292bd4f2aeb710 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Thu, 21 Sep 2023 15:44:17 +0800 Subject: sched/numa, mm: make numa migrate functions to take a folio The cpupid (or access time) is stored in the head page for THP, so it is safely to make should_numa_migrate_memory() and numa_hint_fault_latency() to take a folio. This is in preparation for large folio numa balancing. Link: https://lkml.kernel.org/r/20230921074417.24004-7-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/sched/numa_balancing.h | 6 +++--- kernel/sched/fair.c | 12 ++++++------ mm/mempolicy.c | 2 +- 3 files changed, 10 insertions(+), 10 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched/numa_balancing.h b/include/linux/sched/numa_balancing.h index 3988762efe15..06a9d35650f0 100644 --- a/include/linux/sched/numa_balancing.h +++ b/include/linux/sched/numa_balancing.h @@ -20,8 +20,8 @@ extern void task_numa_fault(int last_node, int node, int pages, int flags); extern pid_t task_numa_group_id(struct task_struct *p); extern void set_numabalancing_state(bool enabled); extern void task_numa_free(struct task_struct *p, bool final); -extern bool should_numa_migrate_memory(struct task_struct *p, struct page *page, - int src_nid, int dst_cpu); +bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio, + int src_nid, int dst_cpu); #else static inline void task_numa_fault(int last_node, int node, int pages, int flags) @@ -38,7 +38,7 @@ static inline void task_numa_free(struct task_struct *p, bool final) { } static inline bool should_numa_migrate_memory(struct task_struct *p, - struct page *page, int src_nid, int dst_cpu) + struct folio *folio, int src_nid, int dst_cpu) { return true; } diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index cb225921bbca..42aefe7e6fdc 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1722,12 +1722,12 @@ static bool pgdat_free_space_enough(struct pglist_data *pgdat) * The smaller the hint page fault latency, the higher the possibility * for the page to be hot. */ -static int numa_hint_fault_latency(struct page *page) +static int numa_hint_fault_latency(struct folio *folio) { int last_time, time; time = jiffies_to_msecs(jiffies); - last_time = xchg_page_access_time(page, time); + last_time = xchg_page_access_time(&folio->page, time); return (time - last_time) & PAGE_ACCESS_TIME_MASK; } @@ -1784,7 +1784,7 @@ static void numa_promotion_adjust_threshold(struct pglist_data *pgdat, } } -bool should_numa_migrate_memory(struct task_struct *p, struct page * page, +bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio, int src_nid, int dst_cpu) { struct numa_group *ng = deref_curr_numa_group(p); @@ -1814,16 +1814,16 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, numa_promotion_adjust_threshold(pgdat, rate_limit, def_th); th = pgdat->nbp_threshold ? : def_th; - latency = numa_hint_fault_latency(page); + latency = numa_hint_fault_latency(folio); if (latency >= th) return false; return !numa_promotion_rate_limit(pgdat, rate_limit, - thp_nr_pages(page)); + folio_nr_pages(folio)); } this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid); - last_cpupid = page_cpupid_xchg_last(page, this_cpupid); + last_cpupid = page_cpupid_xchg_last(&folio->page, this_cpupid); if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) && !node_is_toptier(src_nid) && !cpupid_valid(last_cpupid)) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 69c0eac7292c..abd94f4c7f6b 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2642,7 +2642,7 @@ int mpol_misplaced(struct folio *folio, struct vm_area_struct *vma, if (pol->flags & MPOL_F_MORON) { polnid = thisnid; - if (!should_numa_migrate_memory(current, &folio->page, curnid, + if (!should_numa_migrate_memory(current, folio, curnid, thiscpu)) goto out; } -- cgit v1.2.3 From 3c6f33b7273a7e2f2b2497b62c8400bd957b2fbe Mon Sep 17 00:00:00 2001 From: Stefan Roesch Date: Fri, 22 Sep 2023 14:11:40 -0700 Subject: mm/ksm: support fork/exec for prctl Patch series "mm/ksm: add fork-exec support for prctl", v4. A process can enable KSM with the prctl system call. When the process is forked the KSM flag is inherited by the child process. However if the process is executing an exec system call directly after the fork, the KSM setting is cleared. This patch series addresses this problem. 1) Change the mask in coredump.h for execing a new process 2) Add a new test case in ksm_functional_tests This patch (of 2): Today we have two ways to enable KSM: 1) madvise system call This allows to enable KSM for a memory region for a long time. 2) prctl system call This is a recent addition to enable KSM for the complete process. In addition when a process is forked, the KSM setting is inherited. This change only affects the second case. One of the use cases for (2) was to support the ability to enable KSM for cgroups. This allows systemd to enable KSM for the seed process. By enabling it in the seed process all child processes inherit the setting. This works correctly when the process is forked. However it doesn't support fork/exec workflow. From the previous cover letter: .... Use case 3: With the madvise call sharing opportunities are only enabled for the current process: it is a workload-local decision. A considerable number of sharing opportunities may exist across multiple workloads or jobs (if they are part of the same security domain). Only a higler level entity like a job scheduler or container can know for certain if its running one or more instances of a job. That job scheduler however doesn't have the necessary internal workload knowledge to make targeted madvise calls. .... In addition it can also be a bit surprising that fork keeps the KSM setting and fork/exec does not. Link: https://lkml.kernel.org/r/20230922211141.320789-1-shr@devkernel.io Link: https://lkml.kernel.org/r/20230922211141.320789-2-shr@devkernel.io Signed-off-by: Stefan Roesch Fixes: d7597f59d1d3 ("mm: add new api to enable ksm per process") Reviewed-by: David Hildenbrand Reported-by: Carl Klemm Tested-by: Carl Klemm Cc: Johannes Weiner Cc: Rik van Riel Signed-off-by: Andrew Morton --- include/linux/sched/coredump.h | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h index 1b37fa8fc723..02f5090ffea2 100644 --- a/include/linux/sched/coredump.h +++ b/include/linux/sched/coredump.h @@ -71,6 +71,7 @@ static inline int get_dumpable(struct mm_struct *mm) #define MMF_UNSTABLE 22 /* mm is unstable for copy_from_user */ #define MMF_HUGE_ZERO_PAGE 23 /* mm has ever used the global huge zero page */ #define MMF_DISABLE_THP 24 /* disable THP for all VMAs */ +#define MMF_DISABLE_THP_MASK (1 << MMF_DISABLE_THP) #define MMF_OOM_REAP_QUEUED 25 /* mm was queued for oom_reaper */ #define MMF_MULTIPROCESS 26 /* mm is shared between processes */ /* @@ -85,13 +86,15 @@ static inline int get_dumpable(struct mm_struct *mm) #define MMF_HAS_MDWE 28 #define MMF_HAS_MDWE_MASK (1 << MMF_HAS_MDWE) -#define MMF_DISABLE_THP_MASK (1 << MMF_DISABLE_THP) -#define MMF_INIT_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\ - MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK) +#define MMF_HAS_MDWE_NO_INHERIT 29 -#define MMF_VM_MERGE_ANY 29 -#define MMF_HAS_MDWE_NO_INHERIT 30 +#define MMF_VM_MERGE_ANY 30 +#define MMF_VM_MERGE_ANY_MASK (1 << MMF_VM_MERGE_ANY) + +#define MMF_INIT_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\ + MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\ + MMF_VM_MERGE_ANY_MASK) static inline unsigned long mmf_init_flags(unsigned long flags) { -- cgit v1.2.3 From a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3 Mon Sep 17 00:00:00 2001 From: Sidhartha Kumar Date: Tue, 26 Sep 2023 12:20:17 -0700 Subject: mm/filemap: remove hugetlb special casing in filemap.c Remove special cased hugetlb handling code within the page cache by changing the granularity of ->index to the base page size rather than the huge page size. The motivation of this patch is to reduce complexity within the filemap code while also increasing performance by removing branches that are evaluated on every page cache lookup. To support the change in index, new wrappers for hugetlb page cache interactions are added. These wrappers perform the conversion to a linear index which is now expected by the page cache for huge pages. ========================= PERFORMANCE ====================================== Perf was used to check the performance differences after the patch. Overall the performance is similar to mainline with a very small larger overhead that occurs in __filemap_add_folio() and hugetlb_add_to_page_cache(). This is because of the larger overhead that occurs in xa_load() and xa_store() as the xarray is now using more entries to store hugetlb folios in the page cache. Timing aarch64 2MB Page Size 6.5-rc3 + this patch: [root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt real 1m49.568s user 0m0.000s sys 1m49.461s 6.5-rc3: [root]# time fallocate -l 700GB test.txt real 1m47.495s user 0m0.000s sys 1m47.370s 1GB Page Size 6.5-rc3 + this patch: [root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt real 1m47.024s user 0m0.000s sys 1m46.921s 6.5-rc3: [root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt real 1m44.551s user 0m0.000s sys 1m44.438s x86 2MB Page Size 6.5-rc3 + this patch: [root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt real 0m22.383s user 0m0.000s sys 0m22.255s 6.5-rc3: [opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt real 0m22.735s user 0m0.038s sys 0m22.567s 1GB Page Size 6.5-rc3 + this patch: [root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt real 0m25.786s user 0m0.001s sys 0m25.589s 6.5-rc3: [root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt real 0m33.454s user 0m0.001s sys 0m33.193s aarch64: workload - fallocate a 700GB file backed by huge pages 6.5-rc3 + this patch: 2MB Page Size: --100.00%--__arm64_sys_fallocate ksys_fallocate vfs_fallocate hugetlbfs_fallocate | |--95.04%--__pi_clear_page | |--3.57%--clear_huge_page | | | |--2.63%--rcu_all_qs | | | --0.91%--__cond_resched | --0.67%--__cond_resched 0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache 0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio 6.5-rc3 2MB Page Size: --100.00%--__arm64_sys_fallocate ksys_fallocate vfs_fallocate hugetlbfs_fallocate | |--94.91%--__pi_clear_page | |--4.11%--clear_huge_page | | | |--3.00%--rcu_all_qs | | | --1.10%--__cond_resched | --0.59%--__cond_resched 0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache 0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio x86 workload - fallocate a 100GB file backed by huge pages 6.5-rc3 + this patch: 2MB Page Size: hugetlbfs_fallocate | --99.57%--clear_huge_page | --98.47%--clear_page_erms | --0.53%--asm_sysvec_apic_timer_interrupt 0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load 0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache 0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio 0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store 6.5-rc3 2MB Page Size: --99.93%--__x64_sys_fallocate vfs_fallocate hugetlbfs_fallocate | --99.38%--clear_huge_page | |--98.40%--clear_page_erms | --0.59%--__cond_resched 0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio ========================= TESTING ====================================== This patch passes libhugetlbfs tests and LTP hugetlb tests ********** TEST SUMMARY * 2M * 32-bit 64-bit * Total testcases: 110 113 * Skipped: 0 0 * PASS: 107 113 * FAIL: 0 0 * Killed by signal: 3 0 * Bad configuration: 0 0 * Expected FAIL: 0 0 * Unexpected PASS: 0 0 * Test not present: 0 0 * Strange test result: 0 0 ********** Done executing testcases. LTP Version: 20220527-178-g2761a81c4 page migration was also tested using Mike Kravetz's test program.[8] [dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug] Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Signed-off-by: Dan Carpenter Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton --- fs/hugetlbfs/inode.c | 37 +++++++++++++++++++------------------ include/linux/hugetlb.h | 12 ++++++++++++ include/linux/pagemap.h | 32 ++------------------------------ mm/filemap.c | 34 ++++++++++------------------------ mm/hugetlb.c | 32 ++++++-------------------------- mm/migrate.c | 6 +++--- 6 files changed, 52 insertions(+), 101 deletions(-) (limited to 'include/linux') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 60fce26ff937..926d01c493fb 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -334,7 +334,7 @@ static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to) ssize_t retval = 0; while (iov_iter_count(to)) { - struct page *page; + struct folio *folio; size_t nr, copied, want; /* nr is the maximum number of bytes to copy from this page */ @@ -352,18 +352,18 @@ static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to) } nr = nr - offset; - /* Find the page */ - page = find_lock_page(mapping, index); - if (unlikely(page == NULL)) { + /* Find the folio */ + folio = filemap_lock_hugetlb_folio(h, mapping, index); + if (IS_ERR(folio)) { /* * We have a HOLE, zero out the user-buffer for the * length of the hole or request. */ copied = iov_iter_zero(nr, to); } else { - unlock_page(page); + folio_unlock(folio); - if (!PageHWPoison(page)) + if (!folio_test_has_hwpoisoned(folio)) want = nr; else { /* @@ -371,19 +371,19 @@ static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to) * touching the 1st raw HWPOISON subpage after * offset. */ - want = adjust_range_hwpoison(page, offset, nr); + want = adjust_range_hwpoison(&folio->page, offset, nr); if (want == 0) { - put_page(page); + folio_put(folio); retval = -EIO; break; } } /* - * We have the page, copy it to user space buffer. + * We have the folio, copy it to user space buffer. */ - copied = copy_page_to_iter(page, offset, want, to); - put_page(page); + copied = copy_folio_to_iter(folio, offset, want, to); + folio_put(folio); } offset += copied; retval += copied; @@ -661,21 +661,20 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart, { struct hstate *h = hstate_inode(inode); struct address_space *mapping = &inode->i_data; - const pgoff_t start = lstart >> huge_page_shift(h); - const pgoff_t end = lend >> huge_page_shift(h); + const pgoff_t end = lend >> PAGE_SHIFT; struct folio_batch fbatch; pgoff_t next, index; int i, freed = 0; bool truncate_op = (lend == LLONG_MAX); folio_batch_init(&fbatch); - next = start; + next = lstart >> PAGE_SHIFT; while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) { for (i = 0; i < folio_batch_count(&fbatch); ++i) { struct folio *folio = fbatch.folios[i]; u32 hash = 0; - index = folio->index; + index = folio->index >> huge_page_order(h); hash = hugetlb_fault_mutex_hash(mapping, index); mutex_lock(&hugetlb_fault_mutex_table[hash]); @@ -693,7 +692,9 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart, } if (truncate_op) - (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed); + (void)hugetlb_unreserve_pages(inode, + lstart >> huge_page_shift(h), + LONG_MAX, freed); } static void hugetlbfs_evict_inode(struct inode *inode) @@ -741,7 +742,7 @@ static void hugetlbfs_zero_partial_page(struct hstate *h, pgoff_t idx = start >> huge_page_shift(h); struct folio *folio; - folio = filemap_lock_folio(mapping, idx); + folio = filemap_lock_hugetlb_folio(h, mapping, idx); if (IS_ERR(folio)) return; @@ -886,7 +887,7 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, mutex_lock(&hugetlb_fault_mutex_table[hash]); /* See if already present in mapping to avoid alloc/free */ - folio = filemap_get_folio(mapping, index); + folio = filemap_get_folio(mapping, index << huge_page_order(h)); if (!IS_ERR(folio)) { folio_put(folio); mutex_unlock(&hugetlb_fault_mutex_table[hash]); diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index a30686e649f7..d935b0584f1d 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -812,6 +812,12 @@ static inline unsigned int blocks_per_huge_page(struct hstate *h) return huge_page_size(h) / 512; } +static inline struct folio *filemap_lock_hugetlb_folio(struct hstate *h, + struct address_space *mapping, pgoff_t idx) +{ + return filemap_lock_folio(mapping, idx << huge_page_order(h)); +} + #include #ifndef is_hugepage_only_range @@ -1008,6 +1014,12 @@ static inline struct hugepage_subpool *hugetlb_folio_subpool(struct folio *folio return NULL; } +static inline struct folio *filemap_lock_hugetlb_folio(struct hstate *h, + struct address_space *mapping, pgoff_t idx) +{ + return NULL; +} + static inline int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list) { diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 351c3b7f93a1..759b29d9a69a 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -789,9 +789,6 @@ static inline pgoff_t folio_next_index(struct folio *folio) */ static inline struct page *folio_file_page(struct folio *folio, pgoff_t index) { - /* HugeTLBfs indexes the page cache in units of hpage_size */ - if (folio_test_hugetlb(folio)) - return &folio->page; return folio_page(folio, index & (folio_nr_pages(folio) - 1)); } @@ -807,9 +804,6 @@ static inline struct page *folio_file_page(struct folio *folio, pgoff_t index) */ static inline bool folio_contains(struct folio *folio, pgoff_t index) { - /* HugeTLBfs indexes the page cache in units of hpage_size */ - if (folio_test_hugetlb(folio)) - return folio->index == index; return index - folio_index(folio) < folio_nr_pages(folio); } @@ -867,10 +861,9 @@ static inline struct folio *read_mapping_folio(struct address_space *mapping, } /* - * Get index of the page within radix-tree (but not for hugetlb pages). - * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE) + * Get the offset in PAGE_SIZE (even for hugetlb pages). */ -static inline pgoff_t page_to_index(struct page *page) +static inline pgoff_t page_to_pgoff(struct page *page) { struct page *head; @@ -885,19 +878,6 @@ static inline pgoff_t page_to_index(struct page *page) return head->index + page - head; } -extern pgoff_t hugetlb_basepage_index(struct page *page); - -/* - * Get the offset in PAGE_SIZE (even for hugetlb pages). - * (TODO: hugetlb pages should have ->index in PAGE_SIZE) - */ -static inline pgoff_t page_to_pgoff(struct page *page) -{ - if (unlikely(PageHuge(page))) - return hugetlb_basepage_index(page); - return page_to_index(page); -} - /* * Return byte-offset into filesystem object for page. */ @@ -934,24 +914,16 @@ static inline loff_t folio_file_pos(struct folio *folio) /* * Get the offset in PAGE_SIZE (even for hugetlb folios). - * (TODO: hugetlb folios should have ->index in PAGE_SIZE) */ static inline pgoff_t folio_pgoff(struct folio *folio) { - if (unlikely(folio_test_hugetlb(folio))) - return hugetlb_basepage_index(&folio->page); return folio->index; } -extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma, - unsigned long address); - static inline pgoff_t linear_page_index(struct vm_area_struct *vma, unsigned long address) { pgoff_t pgoff; - if (unlikely(is_vm_hugetlb_page(vma))) - return linear_hugepage_index(vma, address); pgoff = (address - vma->vm_start) >> PAGE_SHIFT; pgoff += vma->vm_pgoff; return pgoff; diff --git a/mm/filemap.c b/mm/filemap.c index 9481ffaf24e6..340c693112a9 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -131,11 +131,8 @@ static void page_cache_delete(struct address_space *mapping, mapping_set_update(&xas, mapping); - /* hugetlb pages are represented by a single entry in the xarray */ - if (!folio_test_hugetlb(folio)) { - xas_set_order(&xas, folio->index, folio_order(folio)); - nr = folio_nr_pages(folio); - } + xas_set_order(&xas, folio->index, folio_order(folio)); + nr = folio_nr_pages(folio); VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); @@ -234,7 +231,7 @@ void filemap_free_folio(struct address_space *mapping, struct folio *folio) if (free_folio) free_folio(folio); - if (folio_test_large(folio) && !folio_test_hugetlb(folio)) + if (folio_test_large(folio)) refs = folio_nr_pages(folio); folio_put_refs(folio, refs); } @@ -855,14 +852,15 @@ noinline int __filemap_add_folio(struct address_space *mapping, if (!huge) { int error = mem_cgroup_charge(folio, NULL, gfp); - VM_BUG_ON_FOLIO(index & (folio_nr_pages(folio) - 1), folio); if (error) return error; charged = true; - xas_set_order(&xas, index, folio_order(folio)); - nr = folio_nr_pages(folio); } + VM_BUG_ON_FOLIO(index & (folio_nr_pages(folio) - 1), folio); + xas_set_order(&xas, index, folio_order(folio)); + nr = folio_nr_pages(folio); + gfp &= GFP_RECLAIM_MASK; folio_ref_add(folio, nr); folio->mapping = mapping; @@ -2040,7 +2038,7 @@ unsigned find_get_entries(struct address_space *mapping, pgoff_t *start, int idx = folio_batch_count(fbatch) - 1; folio = fbatch->folios[idx]; - if (!xa_is_value(folio) && !folio_test_hugetlb(folio)) + if (!xa_is_value(folio)) nr = folio_nr_pages(folio); *start = indices[idx] + nr; } @@ -2104,7 +2102,7 @@ put: int idx = folio_batch_count(fbatch) - 1; folio = fbatch->folios[idx]; - if (!xa_is_value(folio) && !folio_test_hugetlb(folio)) + if (!xa_is_value(folio)) nr = folio_nr_pages(folio); *start = indices[idx] + nr; } @@ -2145,9 +2143,6 @@ unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start, continue; if (!folio_batch_add(fbatch, folio)) { unsigned long nr = folio_nr_pages(folio); - - if (folio_test_hugetlb(folio)) - nr = 1; *start = folio->index + nr; goto out; } @@ -2213,9 +2208,6 @@ unsigned filemap_get_folios_contig(struct address_space *mapping, if (!folio_batch_add(fbatch, folio)) { nr = folio_nr_pages(folio); - - if (folio_test_hugetlb(folio)) - nr = 1; *start = folio->index + nr; goto out; } @@ -2232,10 +2224,7 @@ update_start: if (nr) { folio = fbatch->folios[nr - 1]; - if (folio_test_hugetlb(folio)) - *start = folio->index + 1; - else - *start = folio_next_index(folio); + *start = folio->index + folio_nr_pages(folio); } out: rcu_read_unlock(); @@ -2273,9 +2262,6 @@ unsigned filemap_get_folios_tag(struct address_space *mapping, pgoff_t *start, continue; if (!folio_batch_add(fbatch, folio)) { unsigned long nr = folio_nr_pages(folio); - - if (folio_test_hugetlb(folio)) - nr = 1; *start = folio->index + nr; goto out; } diff --git a/mm/hugetlb.c b/mm/hugetlb.c index de220e3ff8be..0aaf28ce32e5 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -952,7 +952,7 @@ static long region_count(struct resv_map *resv, long f, long t) /* * Convert the address within this vma to the page offset within - * the mapping, in pagecache page units; huge pages here. + * the mapping, huge page units here. */ static pgoff_t vma_hugecache_offset(struct hstate *h, struct vm_area_struct *vma, unsigned long address) @@ -961,13 +961,6 @@ static pgoff_t vma_hugecache_offset(struct hstate *h, (vma->vm_pgoff >> huge_page_order(h)); } -pgoff_t linear_hugepage_index(struct vm_area_struct *vma, - unsigned long address) -{ - return vma_hugecache_offset(hstate_vma(vma), vma, address); -} -EXPORT_SYMBOL_GPL(linear_hugepage_index); - /** * vma_kernel_pagesize - Page size granularity for this VMA. * @vma: The user mapping. @@ -2074,20 +2067,6 @@ struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage) return NULL; } -pgoff_t hugetlb_basepage_index(struct page *page) -{ - struct page *page_head = compound_head(page); - pgoff_t index = page_index(page_head); - unsigned long compound_idx; - - if (compound_order(page_head) > MAX_ORDER) - compound_idx = page_to_pfn(page) - page_to_pfn(page_head); - else - compound_idx = page - page_head; - - return (index << compound_order(page_head)) + compound_idx; -} - static struct folio *alloc_buddy_hugetlb_folio(struct hstate *h, gfp_t gfp_mask, int nid, nodemask_t *nmask, nodemask_t *node_alloc_noretry) @@ -5772,7 +5751,7 @@ static bool hugetlbfs_pagecache_present(struct hstate *h, struct vm_area_struct *vma, unsigned long address) { struct address_space *mapping = vma->vm_file->f_mapping; - pgoff_t idx = vma_hugecache_offset(h, vma, address); + pgoff_t idx = linear_page_index(vma, address); struct folio *folio; folio = filemap_get_folio(mapping, idx); @@ -5789,6 +5768,7 @@ int hugetlb_add_to_page_cache(struct folio *folio, struct address_space *mapping struct hstate *h = hstate_inode(inode); int err; + idx <<= huge_page_order(h); __folio_set_locked(folio); err = __filemap_add_folio(mapping, folio, idx, GFP_KERNEL, NULL); @@ -5896,7 +5876,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, * before we get page_table_lock. */ new_folio = false; - folio = filemap_lock_folio(mapping, idx); + folio = filemap_lock_hugetlb_folio(h, mapping, idx); if (IS_ERR(folio)) { size = i_size_read(mapping->host) >> huge_page_shift(h); if (idx >= size) @@ -6205,7 +6185,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, /* Just decrements count, does not deallocate */ vma_end_reservation(h, vma, haddr); - pagecache_folio = filemap_lock_folio(mapping, idx); + pagecache_folio = filemap_lock_hugetlb_folio(h, mapping, idx); if (IS_ERR(pagecache_folio)) pagecache_folio = NULL; } @@ -6338,7 +6318,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, if (is_continue) { ret = -EFAULT; - folio = filemap_lock_folio(mapping, idx); + folio = filemap_lock_hugetlb_folio(h, mapping, idx); if (IS_ERR(folio)) goto out; folio_in_pagecache = true; diff --git a/mm/migrate.c b/mm/migrate.c index 7d1804c4a5d9..942f8c9cd068 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -524,7 +524,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, int expected_count; xas_lock_irq(&xas); - expected_count = 2 + folio_has_private(src); + expected_count = folio_expected_refs(mapping, src); if (!folio_ref_freeze(src, expected_count)) { xas_unlock_irq(&xas); return -EAGAIN; @@ -533,11 +533,11 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, dst->index = src->index; dst->mapping = src->mapping; - folio_get(dst); + folio_ref_add(dst, folio_nr_pages(dst)); xas_store(&xas, dst); - folio_ref_unfreeze(src, expected_count - 1); + folio_ref_unfreeze(src, expected_count - folio_nr_pages(src)); xas_unlock_irq(&xas); -- cgit v1.2.3 From 07a8bdd4120ced3490ef9adf51b8086af0aaa8e7 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Tue, 26 Sep 2023 14:06:25 +0800 Subject: memory tiering: add abstract distance calculation algorithms management Patch series "memory tiering: calculate abstract distance based on ACPI HMAT", v4. We have the explicit memory tiers framework to manage systems with multiple types of memory, e.g., DRAM in DIMM slots and CXL memory devices. Where, same kind of memory devices will be grouped into memory types, then put into memory tiers. To describe the performance of a memory type, abstract distance is defined. Which is in direct proportion to the memory latency and inversely proportional to the memory bandwidth. To keep the code as simple as possible, fixed abstract distance is used in dax/kmem to describe slow memory such as Optane DCPMM. To support more memory types, in this series, we added the abstract distance calculation algorithm management mechanism, provided a algorithm implementation based on ACPI HMAT, and used the general abstract distance calculation interface in dax/kmem driver. So, dax/kmem can support HBM (high bandwidth memory) in addition to the original Optane DCPMM. This patch (of 4): The abstract distance may be calculated by various drivers, such as ACPI HMAT, CXL CDAT, etc. While it may be used by various code which hot-add memory node, such as dax/kmem etc. To decouple the algorithm users and the providers, the abstract distance calculation algorithms management mechanism is implemented in this patch. It provides interface for the providers to register the implementation, and interface for the users. Multiple algorithm implementations can cooperate via calculating abstract distance for different memory nodes. The preference of algorithm implementations can be specified via priority (notifier_block.priority). Link: https://lkml.kernel.org/r/20230926060628.265989-1-ying.huang@intel.com Link: https://lkml.kernel.org/r/20230926060628.265989-2-ying.huang@intel.com Signed-off-by: "Huang, Ying" Tested-by: Bharata B Rao Reviewed-by: Alistair Popple Reviewed-by: Dave Jiang Cc: Aneesh Kumar K.V Cc: Wei Xu Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Yang Shi Cc: Rafael J Wysocki Signed-off-by: Andrew Morton --- include/linux/memory-tiers.h | 19 ++++++++++++++ mm/memory-tiers.c | 59 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 78 insertions(+) (limited to 'include/linux') diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index 4fa178b50784..fddc59990644 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -6,6 +6,7 @@ #include #include #include +#include /* * Each tier cover a abstrace distance chunk size of 128 */ @@ -36,6 +37,9 @@ struct memory_dev_type *alloc_memory_type(int adistance); void put_memory_type(struct memory_dev_type *memtype); void init_node_memory_type(int node, struct memory_dev_type *default_type); void clear_node_memory_type(int node, struct memory_dev_type *memtype); +int register_mt_adistance_algorithm(struct notifier_block *nb); +int unregister_mt_adistance_algorithm(struct notifier_block *nb); +int mt_calc_adistance(int node, int *adist); #ifdef CONFIG_MIGRATION int next_demotion_node(int node); void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets); @@ -97,5 +101,20 @@ static inline bool node_is_toptier(int node) { return true; } + +static inline int register_mt_adistance_algorithm(struct notifier_block *nb) +{ + return 0; +} + +static inline int unregister_mt_adistance_algorithm(struct notifier_block *nb) +{ + return 0; +} + +static inline int mt_calc_adistance(int node, int *adist) +{ + return NOTIFY_DONE; +} #endif /* CONFIG_NUMA */ #endif /* _LINUX_MEMORY_TIERS_H */ diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index 876d8a5e210e..4301e7e89223 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -5,6 +5,7 @@ #include #include #include +#include #include "internal.h" @@ -105,6 +106,8 @@ static int top_tier_adistance; static struct demotion_nodes *node_demotion __read_mostly; #endif /* CONFIG_MIGRATION */ +static BLOCKING_NOTIFIER_HEAD(mt_adistance_algorithms); + static inline struct memory_tier *to_memory_tier(struct device *device) { return container_of(device, struct memory_tier, dev); @@ -592,6 +595,62 @@ void clear_node_memory_type(int node, struct memory_dev_type *memtype) } EXPORT_SYMBOL_GPL(clear_node_memory_type); +/** + * register_mt_adistance_algorithm() - Register memory tiering abstract distance algorithm + * @nb: The notifier block which describe the algorithm + * + * Return: 0 on success, errno on error. + * + * Every memory tiering abstract distance algorithm provider needs to + * register the algorithm with register_mt_adistance_algorithm(). To + * calculate the abstract distance for a specified memory node, the + * notifier function will be called unless some high priority + * algorithm has provided result. The prototype of the notifier + * function is as follows, + * + * int (*algorithm_notifier)(struct notifier_block *nb, + * unsigned long nid, void *data); + * + * Where "nid" specifies the memory node, "data" is the pointer to the + * returned abstract distance (that is, "int *adist"). If the + * algorithm provides the result, NOTIFY_STOP should be returned. + * Otherwise, return_value & %NOTIFY_STOP_MASK == 0 to allow the next + * algorithm in the chain to provide the result. + */ +int register_mt_adistance_algorithm(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&mt_adistance_algorithms, nb); +} +EXPORT_SYMBOL_GPL(register_mt_adistance_algorithm); + +/** + * unregister_mt_adistance_algorithm() - Unregister memory tiering abstract distance algorithm + * @nb: the notifier block which describe the algorithm + * + * Return: 0 on success, errno on error. + */ +int unregister_mt_adistance_algorithm(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&mt_adistance_algorithms, nb); +} +EXPORT_SYMBOL_GPL(unregister_mt_adistance_algorithm); + +/** + * mt_calc_adistance() - Calculate abstract distance with registered algorithms + * @node: the node to calculate abstract distance for + * @adist: the returned abstract distance + * + * Return: if return_value & %NOTIFY_STOP_MASK != 0, then some + * abstract distance algorithm provides the result, and return it via + * @adist. Otherwise, no algorithm can provide the result and @adist + * will be kept as it is. + */ +int mt_calc_adistance(int node, int *adist) +{ + return blocking_notifier_call_chain(&mt_adistance_algorithms, node, adist); +} +EXPORT_SYMBOL_GPL(mt_calc_adistance); + static int __meminit memtier_hotplug_callback(struct notifier_block *self, unsigned long action, void *_arg) { -- cgit v1.2.3 From 3718c02dbd4c88d47b5af003acdb3d1112604ea3 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Tue, 26 Sep 2023 14:06:27 +0800 Subject: acpi, hmat: calculate abstract distance with HMAT A memory tiering abstract distance calculation algorithm based on ACPI HMAT is implemented. The basic idea is as follows. The performance attributes of system default DRAM nodes are recorded as the base line. Whose abstract distance is MEMTIER_ADISTANCE_DRAM. Then, the ratio of the abstract distance of a memory node (target) to MEMTIER_ADISTANCE_DRAM is scaled based on the ratio of the performance attributes of the node to that of the default DRAM nodes. The functions to record the read/write latency/bandwidth of the default DRAM nodes and calculate abstract distance according to read/write latency/bandwidth ratio will be used by CXL CDAT (Coherent Device Attribute Table) and other memory device drivers. So, they are put in memory-tiers.c. Link: https://lkml.kernel.org/r/20230926060628.265989-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" Tested-by: Bharata B Rao Reviewed-by: Dave Jiang Reviewed-by: Alistair Popple Cc: Aneesh Kumar K.V Cc: Wei Xu Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Yang Shi Cc: Rafael J Wysocki Signed-off-by: Andrew Morton --- drivers/acpi/numa/hmat.c | 65 ++++++++++++++++++++++++++- include/linux/memory-tiers.h | 18 ++++++++ mm/memory-tiers.c | 103 ++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 183 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c index 2dee0098f1a9..9ef5f1bdcfdb 100644 --- a/drivers/acpi/numa/hmat.c +++ b/drivers/acpi/numa/hmat.c @@ -24,6 +24,7 @@ #include #include #include +#include static u8 hmat_revision; static int hmat_disable __initdata; @@ -759,6 +760,61 @@ static int hmat_callback(struct notifier_block *self, return NOTIFY_OK; } +static int hmat_set_default_dram_perf(void) +{ + int rc; + int nid, pxm; + struct memory_target *target; + struct node_hmem_attrs *attrs; + + if (!default_dram_type) + return -EIO; + + for_each_node_mask(nid, default_dram_type->nodes) { + pxm = node_to_pxm(nid); + target = find_mem_target(pxm); + if (!target) + continue; + attrs = &target->hmem_attrs[1]; + rc = mt_set_default_dram_perf(nid, attrs, "ACPI HMAT"); + if (rc) + return rc; + } + + return 0; +} + +static int hmat_calculate_adistance(struct notifier_block *self, + unsigned long nid, void *data) +{ + static DECLARE_BITMAP(p_nodes, MAX_NUMNODES); + struct memory_target *target; + struct node_hmem_attrs *perf; + int *adist = data; + int pxm; + + pxm = node_to_pxm(nid); + target = find_mem_target(pxm); + if (!target) + return NOTIFY_OK; + + mutex_lock(&target_lock); + hmat_update_target_attrs(target, p_nodes, 1); + mutex_unlock(&target_lock); + + perf = &target->hmem_attrs[1]; + + if (mt_perf_to_adistance(perf, adist)) + return NOTIFY_OK; + + return NOTIFY_STOP; +} + +static struct notifier_block hmat_adist_nb __meminitdata = { + .notifier_call = hmat_calculate_adistance, + .priority = 100, +}; + static __init void hmat_free_structures(void) { struct memory_target *target, *tnext; @@ -841,8 +897,13 @@ static __init int hmat_init(void) hmat_register_targets(); /* Keep the table and structures if the notifier may use them */ - if (!hotplug_memory_notifier(hmat_callback, HMAT_CALLBACK_PRI)) - return 0; + if (hotplug_memory_notifier(hmat_callback, HMAT_CALLBACK_PRI)) + goto out_put; + + if (!hmat_set_default_dram_perf()) + register_mt_adistance_algorithm(&hmat_adist_nb); + + return 0; out_put: hmat_free_structures(); acpi_put_table(tbl); diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index fddc59990644..59d15c6d3c0d 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -31,8 +31,11 @@ struct memory_dev_type { struct kref kref; }; +struct node_hmem_attrs; + #ifdef CONFIG_NUMA extern bool numa_demotion_enabled; +extern struct memory_dev_type *default_dram_type; struct memory_dev_type *alloc_memory_type(int adistance); void put_memory_type(struct memory_dev_type *memtype); void init_node_memory_type(int node, struct memory_dev_type *default_type); @@ -40,6 +43,9 @@ void clear_node_memory_type(int node, struct memory_dev_type *memtype); int register_mt_adistance_algorithm(struct notifier_block *nb); int unregister_mt_adistance_algorithm(struct notifier_block *nb); int mt_calc_adistance(int node, int *adist); +int mt_set_default_dram_perf(int nid, struct node_hmem_attrs *perf, + const char *source); +int mt_perf_to_adistance(struct node_hmem_attrs *perf, int *adist); #ifdef CONFIG_MIGRATION int next_demotion_node(int node); void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets); @@ -64,6 +70,7 @@ static inline bool node_is_toptier(int node) #else #define numa_demotion_enabled false +#define default_dram_type NULL /* * CONFIG_NUMA implementation returns non NULL error. */ @@ -116,5 +123,16 @@ static inline int mt_calc_adistance(int node, int *adist) { return NOTIFY_DONE; } + +static inline int mt_set_default_dram_perf(int nid, struct node_hmem_attrs *perf, + const char *source) +{ + return -EIO; +} + +static inline int mt_perf_to_adistance(struct node_hmem_attrs *perf, int *adist) +{ + return -EIO; +} #endif /* CONFIG_NUMA */ #endif /* _LINUX_MEMORY_TIERS_H */ diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index 4301e7e89223..085321c77123 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -37,7 +37,7 @@ struct node_memory_type_map { static DEFINE_MUTEX(memory_tier_lock); static LIST_HEAD(memory_tiers); static struct node_memory_type_map node_memory_types[MAX_NUMNODES]; -static struct memory_dev_type *default_dram_type; +struct memory_dev_type *default_dram_type; static struct bus_type memory_tier_subsys = { .name = "memory_tiering", @@ -108,6 +108,11 @@ static struct demotion_nodes *node_demotion __read_mostly; static BLOCKING_NOTIFIER_HEAD(mt_adistance_algorithms); +static bool default_dram_perf_error; +static struct node_hmem_attrs default_dram_perf; +static int default_dram_perf_ref_nid = NUMA_NO_NODE; +static const char *default_dram_perf_ref_source; + static inline struct memory_tier *to_memory_tier(struct device *device) { return container_of(device, struct memory_tier, dev); @@ -595,6 +600,102 @@ void clear_node_memory_type(int node, struct memory_dev_type *memtype) } EXPORT_SYMBOL_GPL(clear_node_memory_type); +static void dump_hmem_attrs(struct node_hmem_attrs *attrs, const char *prefix) +{ + pr_info( +"%sread_latency: %u, write_latency: %u, read_bandwidth: %u, write_bandwidth: %u\n", + prefix, attrs->read_latency, attrs->write_latency, + attrs->read_bandwidth, attrs->write_bandwidth); +} + +int mt_set_default_dram_perf(int nid, struct node_hmem_attrs *perf, + const char *source) +{ + int rc = 0; + + mutex_lock(&memory_tier_lock); + if (default_dram_perf_error) { + rc = -EIO; + goto out; + } + + if (perf->read_latency + perf->write_latency == 0 || + perf->read_bandwidth + perf->write_bandwidth == 0) { + rc = -EINVAL; + goto out; + } + + if (default_dram_perf_ref_nid == NUMA_NO_NODE) { + default_dram_perf = *perf; + default_dram_perf_ref_nid = nid; + default_dram_perf_ref_source = kstrdup(source, GFP_KERNEL); + goto out; + } + + /* + * The performance of all default DRAM nodes is expected to be + * same (that is, the variation is less than 10%). And it + * will be used as base to calculate the abstract distance of + * other memory nodes. + */ + if (abs(perf->read_latency - default_dram_perf.read_latency) * 10 > + default_dram_perf.read_latency || + abs(perf->write_latency - default_dram_perf.write_latency) * 10 > + default_dram_perf.write_latency || + abs(perf->read_bandwidth - default_dram_perf.read_bandwidth) * 10 > + default_dram_perf.read_bandwidth || + abs(perf->write_bandwidth - default_dram_perf.write_bandwidth) * 10 > + default_dram_perf.write_bandwidth) { + pr_info( +"memory-tiers: the performance of DRAM node %d mismatches that of the reference\n" +"DRAM node %d.\n", nid, default_dram_perf_ref_nid); + pr_info(" performance of reference DRAM node %d:\n", + default_dram_perf_ref_nid); + dump_hmem_attrs(&default_dram_perf, " "); + pr_info(" performance of DRAM node %d:\n", nid); + dump_hmem_attrs(perf, " "); + pr_info( +" disable default DRAM node performance based abstract distance algorithm.\n"); + default_dram_perf_error = true; + rc = -EINVAL; + } + +out: + mutex_unlock(&memory_tier_lock); + return rc; +} + +int mt_perf_to_adistance(struct node_hmem_attrs *perf, int *adist) +{ + if (default_dram_perf_error) + return -EIO; + + if (default_dram_perf_ref_nid == NUMA_NO_NODE) + return -ENOENT; + + if (perf->read_latency + perf->write_latency == 0 || + perf->read_bandwidth + perf->write_bandwidth == 0) + return -EINVAL; + + mutex_lock(&memory_tier_lock); + /* + * The abstract distance of a memory node is in direct proportion to + * its memory latency (read + write) and inversely proportional to its + * memory bandwidth (read + write). The abstract distance, memory + * latency, and memory bandwidth of the default DRAM nodes are used as + * the base. + */ + *adist = MEMTIER_ADISTANCE_DRAM * + (perf->read_latency + perf->write_latency) / + (default_dram_perf.read_latency + default_dram_perf.write_latency) * + (default_dram_perf.read_bandwidth + default_dram_perf.write_bandwidth) / + (perf->read_bandwidth + perf->write_bandwidth); + mutex_unlock(&memory_tier_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(mt_perf_to_adistance); + /** * register_mt_adistance_algorithm() - Register memory tiering abstract distance algorithm * @nb: The notifier block which describe the algorithm -- cgit v1.2.3 From 6bc2cfdf82d56863b7cf5e86e37a662b2ae5d47e Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Tue, 26 Sep 2023 14:06:28 +0800 Subject: dax, kmem: calculate abstract distance with general interface Previously, a fixed abstract distance MEMTIER_DEFAULT_DAX_ADISTANCE is used for slow memory type in kmem driver. This limits the usage of kmem driver, for example, it cannot be used for HBM (high bandwidth memory). So, we use the general abstract distance calculation mechanism in kmem drivers to get more accurate abstract distance on systems with proper support. The original MEMTIER_DEFAULT_DAX_ADISTANCE is used as fallback only. Now, multiple memory types may be managed by kmem. These memory types are put into the "kmem_memory_types" list and protected by kmem_memory_type_lock. Link: https://lkml.kernel.org/r/20230926060628.265989-5-ying.huang@intel.com Signed-off-by: "Huang, Ying" Tested-by: Bharata B Rao Reviewed-by: Dave Jiang Reviewed-by: Alistair Popple Cc: Aneesh Kumar K.V Cc: Wei Xu Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Yang Shi Cc: Rafael J Wysocki Signed-off-by: Andrew Morton --- drivers/dax/kmem.c | 62 ++++++++++++++++++++++++++++++++++---------- include/linux/memory-tiers.h | 2 ++ mm/memory-tiers.c | 3 ++- 3 files changed, 53 insertions(+), 14 deletions(-) (limited to 'include/linux') diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c index c57acb73e3db..369c698b7706 100644 --- a/drivers/dax/kmem.c +++ b/drivers/dax/kmem.c @@ -49,14 +49,52 @@ struct dax_kmem_data { struct resource *res[]; }; -static struct memory_dev_type *dax_slowmem_type; +static DEFINE_MUTEX(kmem_memory_type_lock); +static LIST_HEAD(kmem_memory_types); + +static struct memory_dev_type *kmem_find_alloc_memory_type(int adist) +{ + bool found = false; + struct memory_dev_type *mtype; + + mutex_lock(&kmem_memory_type_lock); + list_for_each_entry(mtype, &kmem_memory_types, list) { + if (mtype->adistance == adist) { + found = true; + break; + } + } + if (!found) { + mtype = alloc_memory_type(adist); + if (!IS_ERR(mtype)) + list_add(&mtype->list, &kmem_memory_types); + } + mutex_unlock(&kmem_memory_type_lock); + + return mtype; +} + +static void kmem_put_memory_types(void) +{ + struct memory_dev_type *mtype, *mtn; + + mutex_lock(&kmem_memory_type_lock); + list_for_each_entry_safe(mtype, mtn, &kmem_memory_types, list) { + list_del(&mtype->list); + put_memory_type(mtype); + } + mutex_unlock(&kmem_memory_type_lock); +} + static int dev_dax_kmem_probe(struct dev_dax *dev_dax) { struct device *dev = &dev_dax->dev; unsigned long total_len = 0; struct dax_kmem_data *data; + struct memory_dev_type *mtype; int i, rc, mapped = 0; int numa_node; + int adist = MEMTIER_DEFAULT_DAX_ADISTANCE; /* * Ensure good NUMA information for the persistent memory. @@ -71,6 +109,11 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) return -EINVAL; } + mt_calc_adistance(numa_node, &adist); + mtype = kmem_find_alloc_memory_type(adist); + if (IS_ERR(mtype)) + return PTR_ERR(mtype); + for (i = 0; i < dev_dax->nr_range; i++) { struct range range; @@ -88,7 +131,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) return -EINVAL; } - init_node_memory_type(numa_node, dax_slowmem_type); + init_node_memory_type(numa_node, mtype); rc = -ENOMEM; data = kzalloc(struct_size(data, res, dev_dax->nr_range), GFP_KERNEL); @@ -167,7 +210,7 @@ err_reg_mgid: err_res_name: kfree(data); err_dax_kmem_data: - clear_node_memory_type(numa_node, dax_slowmem_type); + clear_node_memory_type(numa_node, mtype); return rc; } @@ -219,7 +262,7 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax) * for that. This implies this reference will be around * till next reboot. */ - clear_node_memory_type(node, dax_slowmem_type); + clear_node_memory_type(node, NULL); } } #else @@ -251,12 +294,6 @@ static int __init dax_kmem_init(void) if (!kmem_name) return -ENOMEM; - dax_slowmem_type = alloc_memory_type(MEMTIER_DEFAULT_DAX_ADISTANCE); - if (IS_ERR(dax_slowmem_type)) { - rc = PTR_ERR(dax_slowmem_type); - goto err_dax_slowmem_type; - } - rc = dax_driver_register(&device_dax_kmem_driver); if (rc) goto error_dax_driver; @@ -264,8 +301,7 @@ static int __init dax_kmem_init(void) return rc; error_dax_driver: - put_memory_type(dax_slowmem_type); -err_dax_slowmem_type: + kmem_put_memory_types(); kfree_const(kmem_name); return rc; } @@ -275,7 +311,7 @@ static void __exit dax_kmem_exit(void) dax_driver_unregister(&device_dax_kmem_driver); if (!any_hotremove_failed) kfree_const(kmem_name); - put_memory_type(dax_slowmem_type); + kmem_put_memory_types(); } MODULE_AUTHOR("Intel Corporation"); diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index 59d15c6d3c0d..1e39d27bee41 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -24,6 +24,8 @@ struct memory_tier; struct memory_dev_type { /* list of memory types that are part of same tier as this type */ struct list_head tier_sibling; + /* list of memory types that are managed by one driver */ + struct list_head list; /* abstract distance for this specific memory type */ int adistance; /* Nodes of same abstract distance */ diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index 085321c77123..8d5291add2bc 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -586,13 +586,14 @@ EXPORT_SYMBOL_GPL(init_node_memory_type); void clear_node_memory_type(int node, struct memory_dev_type *memtype) { mutex_lock(&memory_tier_lock); - if (node_memory_types[node].memtype == memtype) + if (node_memory_types[node].memtype == memtype || !memtype) node_memory_types[node].map_count--; /* * If we umapped all the attached devices to this node, * clear the node memory type. */ if (!node_memory_types[node].map_count) { + memtype = node_memory_types[node].memtype; node_memory_types[node].memtype = NULL; put_memory_type(memtype); } -- cgit v1.2.3 From b7c67206594a56be2407ae4da54a114c90609e53 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 22 Sep 2023 10:53:28 -0700 Subject: mm/memcg: annotate struct mem_cgroup_threshold_ary with __counted_by Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions). As found with Coccinelle[1], add __counted_by for struct mem_cgroup_threshold_ary. [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci Link: https://lkml.kernel.org/r/20230922175327.work.985-kees@kernel.org Signed-off-by: Kees Cook Acked-by: Shakeel Butt Acked-by: Roman Gushchin Reviewed-by: Gustavo A. R. Silva Acked-by: Michal Hocko Cc: Johannes Weiner Cc: "Matthew Wilcox (Oracle)" Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 031102ac9311..c6029aeaa268 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -143,7 +143,7 @@ struct mem_cgroup_threshold_ary { /* Size of entries[] */ unsigned int size; /* Array of thresholds */ - struct mem_cgroup_threshold entries[]; + struct mem_cgroup_threshold entries[] __counted_by(size); }; struct mem_cgroup_thresholds { -- cgit v1.2.3 From d61ea1cb009532dcbd77a9d44b812704cec60146 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Mon, 21 Aug 2023 19:15:13 +0500 Subject: userfaultfd: UFFD_FEATURE_WP_ASYNC MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Patch series "Implement IOCTL to get and optionally clear info about PTEs", v33. *Motivation* The real motivation for adding PAGEMAP_SCAN IOCTL is to emulate Windows GetWriteWatch() and ResetWriteWatch() syscalls [1]. The GetWriteWatch() retrieves the addresses of the pages that are written to in a region of virtual memory. This syscall is used in Windows applications and games etc. This syscall is being emulated in pretty slow manner in userspace. Our purpose is to enhance the kernel such that we translate it efficiently in a better way. Currently some out of tree hack patches are being used to efficiently emulate it in some kernels. We intend to replace those with these patches. So the whole gaming on Linux can effectively get benefit from this. It means there would be tons of users of this code. CRIU use case [2] was mentioned by Andrei and Danylo: > Use cases for migrating sparse VMAs are binaries sanitized with ASAN, > MSAN or TSAN [3]. All of these sanitizers produce sparse mappings of > shadow memory [4]. Being able to migrate such binaries allows to highly > reduce the amount of work needed to identify and fix post-migration > crashes, which happen constantly. Andrei defines the following uses of this code: * it is more granular and allows us to track changed pages more effectively. The current interface can clear dirty bits for the entire process only. In addition, reading info about pages is a separate operation. It means we must freeze the process to read information about all its pages, reset dirty bits, only then we can start dumping pages. The information about pages becomes more and more outdated, while we are processing pages. The new interface solves both these downsides. First, it allows us to read pte bits and clear the soft-dirty bit atomically. It means that CRIU will not need to freeze processes to pre-dump their memory. Second, it clears soft-dirty bits for a specified region of memory. It means CRIU will have actual info about pages to the moment of dumping them. * The new interface has to be much faster because basic page filtering is happening in the kernel. With the old interface, we have to read pagemap for each page. *Implementation Evolution (Short Summary)* From the definition of GetWriteWatch(), we feel like kernel's soft-dirty feature can be used under the hood with some additions like: * reset soft-dirty flag for only a specific region of memory instead of clearing the flag for the entire process * get and clear soft-dirty flag for a specific region atomically So we decided to use ioctl on pagemap file to read or/and reset soft-dirty flag. But using soft-dirty flag, sometimes we get extra pages which weren't even written. They had become soft-dirty because of VMA merging and VM_SOFTDIRTY flag. This breaks the definition of GetWriteWatch(). We were able to by-pass this short coming by ignoring VM_SOFTDIRTY until David reported that mprotect etc messes up the soft-dirty flag while ignoring VM_SOFTDIRTY [5]. This wasn't happening until [6] got introduced. We discussed if we can revert these patches. But we could not reach to any conclusion. So at this point, I made couple of tries to solve this whole VM_SOFTDIRTY issue by correcting the soft-dirty implementation: * [7] Correct the bug fixed wrongly back in 2014. It had potential to cause regression. We left it behind. * [8] Keep a list of soft-dirty part of a VMA across splits and merges. I got the reply don't increase the size of the VMA by 8 bytes. At this point, we left soft-dirty considering it is too much delicate and userfaultfd [9] seemed like the only way forward. From there onward, we have been basing soft-dirty emulation on userfaultfd wp feature where kernel resolves the faults itself when WP_ASYNC feature is used. It was straight forward to add WP_ASYNC feature in userfautlfd. Now we get only those pages dirty or written-to which are really written in reality. (PS There is another WP_UNPOPULATED userfautfd feature is required which is needed to avoid pre-faulting memory before write-protecting [9].) All the different masks were added on the request of CRIU devs to create interface more generic and better. [1] https://learn.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-getwritewatch [2] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com [3] https://github.com/google/sanitizers [4] https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm#64-bit [5] https://lore.kernel.org/all/bfcae708-db21-04b4-0bbe-712badd03071@redhat.com [6] https://lore.kernel.org/all/20220725142048.30450-1-peterx@redhat.com/ [7] https://lore.kernel.org/all/20221122115007.2787017-1-usama.anjum@collabora.com [8] https://lore.kernel.org/all/20221220162606.1595355-1-usama.anjum@collabora.com [9] https://lore.kernel.org/all/20230306213925.617814-1-peterx@redhat.com [10] https://lore.kernel.org/all/20230125144529.1630917-1-mdanylo@google.com This patch (of 6): Add a new userfaultfd-wp feature UFFD_FEATURE_WP_ASYNC, that allows userfaultfd wr-protect faults to be resolved by the kernel directly. It can be used like a high accuracy version of soft-dirty, without vma modifications during tracking, and also with ranged support by default rather than for a whole mm when reset the protections due to existence of ioctl(UFFDIO_WRITEPROTECT). Several goals of such a dirty tracking interface: 1. All types of memory should be supported and tracable. This is nature for soft-dirty but should mention when the context is userfaultfd, because it used to only support anon/shmem/hugetlb. The problem is for a dirty tracking purpose these three types may not be enough, and it's legal to track anything e.g. any page cache writes from mmap. 2. Protections can be applied to partial of a memory range, without vma split/merge fuss. The hope is that the tracking itself should not affect any vma layout change. It also helps when reset happens because the reset will not need mmap write lock which can block the tracee. 3. Accuracy needs to be maintained. This means we need pte markers to work on any type of VMA. One could question that, the whole concept of async dirty tracking is not really close to fundamentally what userfaultfd used to be: it's not "a fault to be serviced by userspace" anymore. However, using userfaultfd-wp here as a framework is convenient for us in at least: 1. VM_UFFD_WP vma flag, which has a very good name to suite something like this, so we don't need VM_YET_ANOTHER_SOFT_DIRTY. Just use a new feature bit to identify from a sync version of uffd-wp registration. 2. PTE markers logic can be leveraged across the whole kernel to maintain the uffd-wp bit as long as an arch supports, this also applies to this case where uffd-wp bit will be a hint to dirty information and it will not go lost easily (e.g. when some page cache ptes got zapped). 3. Reuse ioctl(UFFDIO_WRITEPROTECT) interface for either starting or resetting a range of memory, while there's no counterpart in the old soft-dirty world, hence if this is wanted in a new design we'll need a new interface otherwise. We can somehow understand that commonality because uffd-wp was fundamentally a similar idea of write-protecting pages just like soft-dirty. This implementation allows WP_ASYNC to imply WP_UNPOPULATED, because so far WP_ASYNC seems to not usable if without WP_UNPOPULATE. This also gives us chance to modify impl of WP_ASYNC just in case it could be not depending on WP_UNPOPULATED anymore in the future kernels. It's also fine to imply that because both features will rely on PTE_MARKER_UFFD_WP config option, so they'll show up together (or both missing) in an UFFDIO_API probe. vma_can_userfault() now allows any VMA if the userfaultfd registration is only about async uffd-wp. So we can track dirty for all kinds of memory including generic file systems (like XFS, EXT4 or BTRFS). One trick worth mention in do_wp_page() is that we need to manually update vmf->orig_pte here because it can be used later with a pte_same() check - this path always has FAULT_FLAG_ORIG_PTE_VALID set in the flags. The major defect of this approach of dirty tracking is we need to populate the pgtables when tracking starts. Soft-dirty doesn't do it like that. It's unwanted in the case where the range of memory to track is huge and unpopulated (e.g., tracking updates on a 10G file with mmap() on top, without having any page cache installed yet). One way to improve this is to allow pte markers exist for larger than PTE level for PMD+. That will not change the interface if to implemented, so we can leave that for later. Link: https://lkml.kernel.org/r/20230821141518.870589-1-usama.anjum@collabora.com Link: https://lkml.kernel.org/r/20230821141518.870589-2-usama.anjum@collabora.com Signed-off-by: Peter Xu Co-developed-by: Muhammad Usama Anjum Signed-off-by: Muhammad Usama Anjum Cc: Alex Sierra Cc: Al Viro Cc: Andrei Vagin Cc: Axel Rasmussen Cc: Christian Brauner Cc: Cyrill Gorcunov Cc: Dan Williams Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Gustavo A. R. Silva Cc: "Liam R. Howlett" Cc: Matthew Wilcox Cc: Michal Miroslaw Cc: Mike Rapoport (IBM) Cc: Nadav Amit Cc: Pasha Tatashin Cc: Paul Gofman Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Yang Shi Cc: Yun Zhou Cc: Michał Mirosław Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/userfaultfd.rst | 35 ++++++++++++++++++++++++++++ fs/userfaultfd.c | 26 +++++++++++++++++---- include/linux/userfaultfd_k.h | 21 ++++++++++++++++- include/uapi/linux/userfaultfd.h | 9 ++++++- mm/hugetlb.c | 32 ++++++++++++++----------- mm/memory.c | 28 +++++++++++++++++++--- 6 files changed, 129 insertions(+), 22 deletions(-) (limited to 'include/linux') diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst index 4349a8c2b978..203e26da5f92 100644 --- a/Documentation/admin-guide/mm/userfaultfd.rst +++ b/Documentation/admin-guide/mm/userfaultfd.rst @@ -244,6 +244,41 @@ write-protected (so future writes will also result in a WP fault). These ioctls support a mode flag (``UFFDIO_COPY_MODE_WP`` or ``UFFDIO_CONTINUE_MODE_WP`` respectively) to configure the mapping this way. +If the userfaultfd context has ``UFFD_FEATURE_WP_ASYNC`` feature bit set, +any vma registered with write-protection will work in async mode rather +than the default sync mode. + +In async mode, there will be no message generated when a write operation +happens, meanwhile the write-protection will be resolved automatically by +the kernel. It can be seen as a more accurate version of soft-dirty +tracking and it can be different in a few ways: + + - The dirty result will not be affected by vma changes (e.g. vma + merging) because the dirty is only tracked by the pte. + + - It supports range operations by default, so one can enable tracking on + any range of memory as long as page aligned. + + - Dirty information will not get lost if the pte was zapped due to + various reasons (e.g. during split of a shmem transparent huge page). + + - Due to a reverted meaning of soft-dirty (page clean when uffd-wp bit + set; dirty when uffd-wp bit cleared), it has different semantics on + some of the memory operations. For example: ``MADV_DONTNEED`` on + anonymous (or ``MADV_REMOVE`` on a file mapping) will be treated as + dirtying of memory by dropping uffd-wp bit during the procedure. + +The user app can collect the "written/dirty" status by looking up the +uffd-wp bit for the pages being interested in /proc/pagemap. + +The page will not be under track of uffd-wp async mode until the page is +explicitly write-protected by ``ioctl(UFFDIO_WRITEPROTECT)`` with the mode +flag ``UFFDIO_WRITEPROTECT_MODE_WP`` set. Trying to resolve a page fault +that was tracked by async mode userfaultfd-wp is invalid. + +When userfaultfd-wp async mode is used alone, it can be applied to all +kinds of memory. + Memory Poisioning Emulation --------------------------- diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 56eaae9dac1a..a7c6ef764e63 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -123,6 +123,11 @@ static bool userfaultfd_is_initialized(struct userfaultfd_ctx *ctx) return ctx->features & UFFD_FEATURE_INITIALIZED; } +static bool userfaultfd_wp_async_ctx(struct userfaultfd_ctx *ctx) +{ + return ctx && (ctx->features & UFFD_FEATURE_WP_ASYNC); +} + /* * Whether WP_UNPOPULATED is enabled on the uffd context. It is only * meaningful when userfaultfd_wp()==true on the vma and when it's @@ -1325,6 +1330,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, bool basic_ioctls; unsigned long start, end, vma_end; struct vma_iterator vmi; + bool wp_async = userfaultfd_wp_async_ctx(ctx); pgoff_t pgoff; user_uffdio_register = (struct uffdio_register __user *) arg; @@ -1399,7 +1405,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, /* check not compatible vmas */ ret = -EINVAL; - if (!vma_can_userfault(cur, vm_flags)) + if (!vma_can_userfault(cur, vm_flags, wp_async)) goto out_unlock; /* @@ -1460,7 +1466,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, for_each_vma_range(vmi, vma, end) { cond_resched(); - BUG_ON(!vma_can_userfault(vma, vm_flags)); + BUG_ON(!vma_can_userfault(vma, vm_flags, wp_async)); BUG_ON(vma->vm_userfaultfd_ctx.ctx && vma->vm_userfaultfd_ctx.ctx != ctx); WARN_ON(!(vma->vm_flags & VM_MAYWRITE)); @@ -1561,6 +1567,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, unsigned long start, end, vma_end; const void __user *buf = (void __user *)arg; struct vma_iterator vmi; + bool wp_async = userfaultfd_wp_async_ctx(ctx); pgoff_t pgoff; ret = -EFAULT; @@ -1615,7 +1622,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, * provides for more strict behavior to notice * unregistration errors. */ - if (!vma_can_userfault(cur, cur->vm_flags)) + if (!vma_can_userfault(cur, cur->vm_flags, wp_async)) goto out_unlock; found = true; @@ -1631,7 +1638,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, for_each_vma_range(vmi, vma, end) { cond_resched(); - BUG_ON(!vma_can_userfault(vma, vma->vm_flags)); + BUG_ON(!vma_can_userfault(vma, vma->vm_flags, wp_async)); /* * Nothing to do: this vma is already registered into this @@ -2018,6 +2025,11 @@ out: return ret; } +bool userfaultfd_wp_async(struct vm_area_struct *vma) +{ + return userfaultfd_wp_async_ctx(vma->vm_userfaultfd_ctx.ctx); +} + static inline unsigned int uffd_ctx_features(__u64 user_features) { /* @@ -2051,6 +2063,11 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, ret = -EPERM; if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE)) goto err_out; + + /* WP_ASYNC relies on WP_UNPOPULATED, choose it unconditionally */ + if (features & UFFD_FEATURE_WP_ASYNC) + features |= UFFD_FEATURE_WP_UNPOPULATED; + /* report all available features and ioctls to userland */ uffdio_api.features = UFFD_API_FEATURES; #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR @@ -2063,6 +2080,7 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, #ifndef CONFIG_PTE_MARKER_UFFD_WP uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM; uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED; + uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC; #endif uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index ac8c6854097c..c98df391bfd8 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -161,11 +161,22 @@ static inline bool userfaultfd_armed(struct vm_area_struct *vma) } static inline bool vma_can_userfault(struct vm_area_struct *vma, - unsigned long vm_flags) + unsigned long vm_flags, + bool wp_async) { + vm_flags &= __VM_UFFD_FLAGS; + if ((vm_flags & VM_UFFD_MINOR) && (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma))) return false; + + /* + * If wp async enabled, and WP is the only mode enabled, allow any + * memory type. + */ + if (wp_async && (vm_flags == VM_UFFD_WP)) + return true; + #ifndef CONFIG_PTE_MARKER_UFFD_WP /* * If user requested uffd-wp but not enabled pte markers for @@ -175,6 +186,8 @@ static inline bool vma_can_userfault(struct vm_area_struct *vma, if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma)) return false; #endif + + /* By default, allow any of anon|shmem|hugetlb */ return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) || vma_is_shmem(vma); } @@ -197,6 +210,7 @@ extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, extern void userfaultfd_unmap_complete(struct mm_struct *mm, struct list_head *uf); extern bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma); +extern bool userfaultfd_wp_async(struct vm_area_struct *vma); #else /* CONFIG_USERFAULTFD */ @@ -297,6 +311,11 @@ static inline bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma) return false; } +static inline bool userfaultfd_wp_async(struct vm_area_struct *vma) +{ + return false; +} + #endif /* CONFIG_USERFAULTFD */ static inline bool userfaultfd_wp_use_markers(struct vm_area_struct *vma) diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h index 62151706c5a3..0dbc81015018 100644 --- a/include/uapi/linux/userfaultfd.h +++ b/include/uapi/linux/userfaultfd.h @@ -40,7 +40,8 @@ UFFD_FEATURE_EXACT_ADDRESS | \ UFFD_FEATURE_WP_HUGETLBFS_SHMEM | \ UFFD_FEATURE_WP_UNPOPULATED | \ - UFFD_FEATURE_POISON) + UFFD_FEATURE_POISON | \ + UFFD_FEATURE_WP_ASYNC) #define UFFD_API_IOCTLS \ ((__u64)1 << _UFFDIO_REGISTER | \ (__u64)1 << _UFFDIO_UNREGISTER | \ @@ -216,6 +217,11 @@ struct uffdio_api { * (i.e. empty ptes). This will be the default behavior for shmem * & hugetlbfs, so this flag only affects anonymous memory behavior * when userfault write-protection mode is registered. + * + * UFFD_FEATURE_WP_ASYNC indicates that userfaultfd write-protection + * asynchronous mode is supported in which the write fault is + * automatically resolved and write-protection is un-set. + * It implies UFFD_FEATURE_WP_UNPOPULATED. */ #define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0) #define UFFD_FEATURE_EVENT_FORK (1<<1) @@ -232,6 +238,7 @@ struct uffdio_api { #define UFFD_FEATURE_WP_HUGETLBFS_SHMEM (1<<12) #define UFFD_FEATURE_WP_UNPOPULATED (1<<13) #define UFFD_FEATURE_POISON (1<<14) +#define UFFD_FEATURE_WP_ASYNC (1<<15) __u64 features; __u64 ioctls; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index dfb4534834f5..bc654b36df9f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6247,21 +6247,27 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, /* Handle userfault-wp first, before trying to lock more pages */ if (userfaultfd_wp(vma) && huge_pte_uffd_wp(huge_ptep_get(ptep)) && (flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { - struct vm_fault vmf = { - .vma = vma, - .address = haddr, - .real_address = address, - .flags = flags, - }; + if (!userfaultfd_wp_async(vma)) { + struct vm_fault vmf = { + .vma = vma, + .address = haddr, + .real_address = address, + .flags = flags, + }; - spin_unlock(ptl); - if (pagecache_folio) { - folio_unlock(pagecache_folio); - folio_put(pagecache_folio); + spin_unlock(ptl); + if (pagecache_folio) { + folio_unlock(pagecache_folio); + folio_put(pagecache_folio); + } + hugetlb_vma_unlock_read(vma); + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + return handle_userfault(&vmf, VM_UFFD_WP); } - hugetlb_vma_unlock_read(vma); - mutex_unlock(&hugetlb_fault_mutex_table[hash]); - return handle_userfault(&vmf, VM_UFFD_WP); + + entry = huge_pte_clear_uffd_wp(entry); + set_huge_pte_at(mm, haddr, ptep, entry); + /* Fallthrough to CoW */ } /* diff --git a/mm/memory.c b/mm/memory.c index 2d209bc4d18c..d0f61d729fb4 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1,3 +1,4 @@ + // SPDX-License-Identifier: GPL-2.0-only /* * linux/mm/memory.c @@ -3349,11 +3350,28 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; struct vm_area_struct *vma = vmf->vma; struct folio *folio = NULL; + pte_t pte; if (likely(!unshare)) { if (userfaultfd_pte_wp(vma, ptep_get(vmf->pte))) { - pte_unmap_unlock(vmf->pte, vmf->ptl); - return handle_userfault(vmf, VM_UFFD_WP); + if (!userfaultfd_wp_async(vma)) { + pte_unmap_unlock(vmf->pte, vmf->ptl); + return handle_userfault(vmf, VM_UFFD_WP); + } + + /* + * Nothing needed (cache flush, TLB invalidations, + * etc.) because we're only removing the uffd-wp bit, + * which is completely invisible to the user. + */ + pte = pte_clear_uffd_wp(ptep_get(vmf->pte)); + + set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); + /* + * Update this to be prepared for following up CoW + * handling + */ + vmf->orig_pte = pte; } /* @@ -4879,8 +4897,11 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) if (vma_is_anonymous(vma)) { if (likely(!unshare) && - userfaultfd_huge_pmd_wp(vma, vmf->orig_pmd)) + userfaultfd_huge_pmd_wp(vma, vmf->orig_pmd)) { + if (userfaultfd_wp_async(vmf->vma)) + goto split; return handle_userfault(vmf, VM_UFFD_WP); + } return do_huge_pmd_wp_page(vmf); } @@ -4892,6 +4913,7 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) } } +split: /* COW or write-notify handled on pte level: split pmd. */ __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL); -- cgit v1.2.3 From 52526ca7fdb905a768a93f8faa418e9b988fc34b Mon Sep 17 00:00:00 2001 From: Muhammad Usama Anjum Date: Mon, 21 Aug 2023 19:15:14 +0500 Subject: fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The PAGEMAP_SCAN IOCTL on the pagemap file can be used to get or optionally clear the info about page table entries. The following operations are supported in this IOCTL: - Scan the address range and get the memory ranges matching the provided criteria. This is performed when the output buffer is specified. - Write-protect the pages. The PM_SCAN_WP_MATCHING is used to write-protect the pages of interest. The PM_SCAN_CHECK_WPASYNC aborts the operation if non-Async Write Protected pages are found. The ``PM_SCAN_WP_MATCHING`` can be used with or without PM_SCAN_CHECK_WPASYNC. - Both of those operations can be combined into one atomic operation where we can get and write protect the pages as well. Following flags about pages are currently supported: - PAGE_IS_WPALLOWED - Page has async-write-protection enabled - PAGE_IS_WRITTEN - Page has been written to from the time it was write protected - PAGE_IS_FILE - Page is file backed - PAGE_IS_PRESENT - Page is present in the memory - PAGE_IS_SWAPPED - Page is in swapped - PAGE_IS_PFNZERO - Page has zero PFN - PAGE_IS_HUGE - Page is THP or Hugetlb backed This IOCTL can be extended to get information about more PTE bits. The entire address range passed by user [start, end) is scanned until either the user provided buffer is full or max_pages have been found. [akpm@linux-foundation.org: update it for "mm: hugetlb: add huge page size param to set_huge_pte_at()"] [akpm@linux-foundation.org: fix CONFIG_HUGETLB_PAGE=n warning] [arnd@arndb.de: hide unused pagemap_scan_backout_range() function] Link: https://lkml.kernel.org/r/20230927060257.2975412-1-arnd@kernel.org [sfr@canb.auug.org.au: fix "fs/proc/task_mmu: hide unused pagemap_scan_backout_range() function"] Link: https://lkml.kernel.org/r/20230928092223.0625c6bf@canb.auug.org.au Link: https://lkml.kernel.org/r/20230821141518.870589-3-usama.anjum@collabora.com Signed-off-by: Muhammad Usama Anjum Signed-off-by: Michał Mirosław Signed-off-by: Arnd Bergmann Signed-off-by: Stephen Rothwell Reviewed-by: Andrei Vagin Reviewed-by: Michał Mirosław Cc: Alex Sierra Cc: Al Viro Cc: Axel Rasmussen Cc: Christian Brauner Cc: Cyrill Gorcunov Cc: Dan Williams Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Gustavo A. R. Silva Cc: "Liam R. Howlett" Cc: Matthew Wilcox Cc: Michal Miroslaw Cc: Mike Rapoport (IBM) Cc: Nadav Amit Cc: Pasha Tatashin Cc: Paul Gofman Cc: Peter Xu Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Yang Shi Cc: Yun Zhou Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 692 ++++++++++++++++++++++++++++++++++++++++++ include/linux/hugetlb.h | 1 + include/linux/userfaultfd_k.h | 7 + include/uapi/linux/fs.h | 59 ++++ mm/hugetlb.c | 5 +- 5 files changed, 762 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 3dd5be96691b..d4ef9a2bf95d 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -20,6 +20,8 @@ #include #include #include +#include +#include #include #include @@ -1761,11 +1763,701 @@ static int pagemap_release(struct inode *inode, struct file *file) return 0; } +#define PM_SCAN_CATEGORIES (PAGE_IS_WPALLOWED | PAGE_IS_WRITTEN | \ + PAGE_IS_FILE | PAGE_IS_PRESENT | \ + PAGE_IS_SWAPPED | PAGE_IS_PFNZERO | \ + PAGE_IS_HUGE) +#define PM_SCAN_FLAGS (PM_SCAN_WP_MATCHING | PM_SCAN_CHECK_WPASYNC) + +struct pagemap_scan_private { + struct pm_scan_arg arg; + unsigned long masks_of_interest, cur_vma_category; + struct page_region *vec_buf; + unsigned long vec_buf_len, vec_buf_index, found_pages; + struct page_region __user *vec_out; +}; + +static unsigned long pagemap_page_category(struct pagemap_scan_private *p, + struct vm_area_struct *vma, + unsigned long addr, pte_t pte) +{ + unsigned long categories = 0; + + if (pte_present(pte)) { + struct page *page; + + categories |= PAGE_IS_PRESENT; + if (!pte_uffd_wp(pte)) + categories |= PAGE_IS_WRITTEN; + + if (p->masks_of_interest & PAGE_IS_FILE) { + page = vm_normal_page(vma, addr, pte); + if (page && !PageAnon(page)) + categories |= PAGE_IS_FILE; + } + + if (is_zero_pfn(pte_pfn(pte))) + categories |= PAGE_IS_PFNZERO; + } else if (is_swap_pte(pte)) { + swp_entry_t swp; + + categories |= PAGE_IS_SWAPPED; + if (!pte_swp_uffd_wp_any(pte)) + categories |= PAGE_IS_WRITTEN; + + if (p->masks_of_interest & PAGE_IS_FILE) { + swp = pte_to_swp_entry(pte); + if (is_pfn_swap_entry(swp) && + !PageAnon(pfn_swap_entry_to_page(swp))) + categories |= PAGE_IS_FILE; + } + } + + return categories; +} + +static void make_uffd_wp_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t *pte) +{ + pte_t ptent = ptep_get(pte); + + if (pte_present(ptent)) { + pte_t old_pte; + + old_pte = ptep_modify_prot_start(vma, addr, pte); + ptent = pte_mkuffd_wp(ptent); + ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent); + } else if (is_swap_pte(ptent)) { + ptent = pte_swp_mkuffd_wp(ptent); + set_pte_at(vma->vm_mm, addr, pte, ptent); + } else { + set_pte_at(vma->vm_mm, addr, pte, + make_pte_marker(PTE_MARKER_UFFD_WP)); + } +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static unsigned long pagemap_thp_category(struct pagemap_scan_private *p, + struct vm_area_struct *vma, + unsigned long addr, pmd_t pmd) +{ + unsigned long categories = PAGE_IS_HUGE; + + if (pmd_present(pmd)) { + struct page *page; + + categories |= PAGE_IS_PRESENT; + if (!pmd_uffd_wp(pmd)) + categories |= PAGE_IS_WRITTEN; + + if (p->masks_of_interest & PAGE_IS_FILE) { + page = vm_normal_page_pmd(vma, addr, pmd); + if (page && !PageAnon(page)) + categories |= PAGE_IS_FILE; + } + + if (is_zero_pfn(pmd_pfn(pmd))) + categories |= PAGE_IS_PFNZERO; + } else if (is_swap_pmd(pmd)) { + swp_entry_t swp; + + categories |= PAGE_IS_SWAPPED; + if (!pmd_swp_uffd_wp(pmd)) + categories |= PAGE_IS_WRITTEN; + + if (p->masks_of_interest & PAGE_IS_FILE) { + swp = pmd_to_swp_entry(pmd); + if (is_pfn_swap_entry(swp) && + !PageAnon(pfn_swap_entry_to_page(swp))) + categories |= PAGE_IS_FILE; + } + } + + return categories; +} + +static void make_uffd_wp_pmd(struct vm_area_struct *vma, + unsigned long addr, pmd_t *pmdp) +{ + pmd_t old, pmd = *pmdp; + + if (pmd_present(pmd)) { + old = pmdp_invalidate_ad(vma, addr, pmdp); + pmd = pmd_mkuffd_wp(old); + set_pmd_at(vma->vm_mm, addr, pmdp, pmd); + } else if (is_migration_entry(pmd_to_swp_entry(pmd))) { + pmd = pmd_swp_mkuffd_wp(pmd); + set_pmd_at(vma->vm_mm, addr, pmdp, pmd); + } +} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + +#ifdef CONFIG_HUGETLB_PAGE +static unsigned long pagemap_hugetlb_category(pte_t pte) +{ + unsigned long categories = PAGE_IS_HUGE; + + /* + * According to pagemap_hugetlb_range(), file-backed HugeTLB + * page cannot be swapped. So PAGE_IS_FILE is not checked for + * swapped pages. + */ + if (pte_present(pte)) { + categories |= PAGE_IS_PRESENT; + if (!huge_pte_uffd_wp(pte)) + categories |= PAGE_IS_WRITTEN; + if (!PageAnon(pte_page(pte))) + categories |= PAGE_IS_FILE; + if (is_zero_pfn(pte_pfn(pte))) + categories |= PAGE_IS_PFNZERO; + } else if (is_swap_pte(pte)) { + categories |= PAGE_IS_SWAPPED; + if (!pte_swp_uffd_wp_any(pte)) + categories |= PAGE_IS_WRITTEN; + } + + return categories; +} + +static void make_uffd_wp_huge_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t ptent) +{ + unsigned long psize; + + if (is_hugetlb_entry_hwpoisoned(ptent) || is_pte_marker(ptent)) + return; + + psize = huge_page_size(hstate_vma(vma)); + + if (is_hugetlb_entry_migration(ptent)) + set_huge_pte_at(vma->vm_mm, addr, ptep, + pte_swp_mkuffd_wp(ptent), psize); + else if (!huge_pte_none(ptent)) + huge_ptep_modify_prot_commit(vma, addr, ptep, ptent, + huge_pte_mkuffd_wp(ptent)); + else + set_huge_pte_at(vma->vm_mm, addr, ptep, + make_pte_marker(PTE_MARKER_UFFD_WP), psize); +} +#endif /* CONFIG_HUGETLB_PAGE */ + +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE) +static void pagemap_scan_backout_range(struct pagemap_scan_private *p, + unsigned long addr, unsigned long end) +{ + struct page_region *cur_buf = &p->vec_buf[p->vec_buf_index]; + + if (cur_buf->start != addr) + cur_buf->end = addr; + else + cur_buf->start = cur_buf->end = 0; + + p->found_pages -= (end - addr) / PAGE_SIZE; +} +#endif + +static bool pagemap_scan_is_interesting_page(unsigned long categories, + const struct pagemap_scan_private *p) +{ + categories ^= p->arg.category_inverted; + if ((categories & p->arg.category_mask) != p->arg.category_mask) + return false; + if (p->arg.category_anyof_mask && !(categories & p->arg.category_anyof_mask)) + return false; + + return true; +} + +static bool pagemap_scan_is_interesting_vma(unsigned long categories, + const struct pagemap_scan_private *p) +{ + unsigned long required = p->arg.category_mask & PAGE_IS_WPALLOWED; + + categories ^= p->arg.category_inverted; + if ((categories & required) != required) + return false; + + return true; +} + +static int pagemap_scan_test_walk(unsigned long start, unsigned long end, + struct mm_walk *walk) +{ + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + unsigned long vma_category = 0; + + if (userfaultfd_wp_async(vma) && userfaultfd_wp_use_markers(vma)) + vma_category |= PAGE_IS_WPALLOWED; + else if (p->arg.flags & PM_SCAN_CHECK_WPASYNC) + return -EPERM; + + if (vma->vm_flags & VM_PFNMAP) + return 1; + + if (!pagemap_scan_is_interesting_vma(vma_category, p)) + return 1; + + p->cur_vma_category = vma_category; + + return 0; +} + +static bool pagemap_scan_push_range(unsigned long categories, + struct pagemap_scan_private *p, + unsigned long addr, unsigned long end) +{ + struct page_region *cur_buf = &p->vec_buf[p->vec_buf_index]; + + /* + * When there is no output buffer provided at all, the sentinel values + * won't match here. There is no other way for `cur_buf->end` to be + * non-zero other than it being non-empty. + */ + if (addr == cur_buf->end && categories == cur_buf->categories) { + cur_buf->end = end; + return true; + } + + if (cur_buf->end) { + if (p->vec_buf_index >= p->vec_buf_len - 1) + return false; + + cur_buf = &p->vec_buf[++p->vec_buf_index]; + } + + cur_buf->start = addr; + cur_buf->end = end; + cur_buf->categories = categories; + + return true; +} + +static int pagemap_scan_output(unsigned long categories, + struct pagemap_scan_private *p, + unsigned long addr, unsigned long *end) +{ + unsigned long n_pages, total_pages; + int ret = 0; + + if (!p->vec_buf) + return 0; + + categories &= p->arg.return_mask; + + n_pages = (*end - addr) / PAGE_SIZE; + if (check_add_overflow(p->found_pages, n_pages, &total_pages) || + total_pages > p->arg.max_pages) { + size_t n_too_much = total_pages - p->arg.max_pages; + *end -= n_too_much * PAGE_SIZE; + n_pages -= n_too_much; + ret = -ENOSPC; + } + + if (!pagemap_scan_push_range(categories, p, addr, *end)) { + *end = addr; + n_pages = 0; + ret = -ENOSPC; + } + + p->found_pages += n_pages; + if (ret) + p->arg.walk_end = *end; + + return ret; +} + +static int pagemap_scan_thp_entry(pmd_t *pmd, unsigned long start, + unsigned long end, struct mm_walk *walk) +{ +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + unsigned long categories; + spinlock_t *ptl; + int ret = 0; + + ptl = pmd_trans_huge_lock(pmd, vma); + if (!ptl) + return -ENOENT; + + categories = p->cur_vma_category | + pagemap_thp_category(p, vma, start, *pmd); + + if (!pagemap_scan_is_interesting_page(categories, p)) + goto out_unlock; + + ret = pagemap_scan_output(categories, p, start, &end); + if (start == end) + goto out_unlock; + + if (~p->arg.flags & PM_SCAN_WP_MATCHING) + goto out_unlock; + if (~categories & PAGE_IS_WRITTEN) + goto out_unlock; + + /* + * Break huge page into small pages if the WP operation + * needs to be performed on a portion of the huge page. + */ + if (end != start + HPAGE_SIZE) { + spin_unlock(ptl); + split_huge_pmd(vma, pmd, start); + pagemap_scan_backout_range(p, start, end); + /* Report as if there was no THP */ + return -ENOENT; + } + + make_uffd_wp_pmd(vma, start, pmd); + flush_tlb_range(vma, start, end); +out_unlock: + spin_unlock(ptl); + return ret; +#else /* !CONFIG_TRANSPARENT_HUGEPAGE */ + return -ENOENT; +#endif +} + +static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start, + unsigned long end, struct mm_walk *walk) +{ + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + unsigned long addr, flush_end = 0; + pte_t *pte, *start_pte; + spinlock_t *ptl; + int ret; + + arch_enter_lazy_mmu_mode(); + + ret = pagemap_scan_thp_entry(pmd, start, end, walk); + if (ret != -ENOENT) { + arch_leave_lazy_mmu_mode(); + return ret; + } + + ret = 0; + start_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl); + if (!pte) { + arch_leave_lazy_mmu_mode(); + walk->action = ACTION_AGAIN; + return 0; + } + + for (addr = start; addr != end; pte++, addr += PAGE_SIZE) { + unsigned long categories = p->cur_vma_category | + pagemap_page_category(p, vma, addr, ptep_get(pte)); + unsigned long next = addr + PAGE_SIZE; + + if (!pagemap_scan_is_interesting_page(categories, p)) + continue; + + ret = pagemap_scan_output(categories, p, addr, &next); + if (next == addr) + break; + + if (~p->arg.flags & PM_SCAN_WP_MATCHING) + continue; + if (~categories & PAGE_IS_WRITTEN) + continue; + + make_uffd_wp_pte(vma, addr, pte); + if (!flush_end) + start = addr; + flush_end = next; + } + + if (flush_end) + flush_tlb_range(vma, start, addr); + + pte_unmap_unlock(start_pte, ptl); + arch_leave_lazy_mmu_mode(); + + cond_resched(); + return ret; +} + +#ifdef CONFIG_HUGETLB_PAGE +static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask, + unsigned long start, unsigned long end, + struct mm_walk *walk) +{ + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + unsigned long categories; + spinlock_t *ptl; + int ret = 0; + pte_t pte; + + if (~p->arg.flags & PM_SCAN_WP_MATCHING) { + /* Go the short route when not write-protecting pages. */ + + pte = huge_ptep_get(ptep); + categories = p->cur_vma_category | pagemap_hugetlb_category(pte); + + if (!pagemap_scan_is_interesting_page(categories, p)) + return 0; + + return pagemap_scan_output(categories, p, start, &end); + } + + i_mmap_lock_write(vma->vm_file->f_mapping); + ptl = huge_pte_lock(hstate_vma(vma), vma->vm_mm, ptep); + + pte = huge_ptep_get(ptep); + categories = p->cur_vma_category | pagemap_hugetlb_category(pte); + + if (!pagemap_scan_is_interesting_page(categories, p)) + goto out_unlock; + + ret = pagemap_scan_output(categories, p, start, &end); + if (start == end) + goto out_unlock; + + if (~categories & PAGE_IS_WRITTEN) + goto out_unlock; + + if (end != start + HPAGE_SIZE) { + /* Partial HugeTLB page WP isn't possible. */ + pagemap_scan_backout_range(p, start, end); + p->arg.walk_end = start; + ret = 0; + goto out_unlock; + } + + make_uffd_wp_huge_pte(vma, start, ptep, pte); + flush_hugetlb_tlb_range(vma, start, end); + +out_unlock: + spin_unlock(ptl); + i_mmap_unlock_write(vma->vm_file->f_mapping); + + return ret; +} +#else +#define pagemap_scan_hugetlb_entry NULL +#endif + +static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end, + int depth, struct mm_walk *walk) +{ + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + int ret, err; + + if (!vma || !pagemap_scan_is_interesting_page(p->cur_vma_category, p)) + return 0; + + ret = pagemap_scan_output(p->cur_vma_category, p, addr, &end); + if (addr == end) + return ret; + + if (~p->arg.flags & PM_SCAN_WP_MATCHING) + return ret; + + err = uffd_wp_range(vma, addr, end - addr, true); + if (err < 0) + ret = err; + + return ret; +} + +static const struct mm_walk_ops pagemap_scan_ops = { + .test_walk = pagemap_scan_test_walk, + .pmd_entry = pagemap_scan_pmd_entry, + .pte_hole = pagemap_scan_pte_hole, + .hugetlb_entry = pagemap_scan_hugetlb_entry, +}; + +static int pagemap_scan_get_args(struct pm_scan_arg *arg, + unsigned long uarg) +{ + if (copy_from_user(arg, (void __user *)uarg, sizeof(*arg))) + return -EFAULT; + + if (arg->size != sizeof(struct pm_scan_arg)) + return -EINVAL; + + /* Validate requested features */ + if (arg->flags & ~PM_SCAN_FLAGS) + return -EINVAL; + if ((arg->category_inverted | arg->category_mask | + arg->category_anyof_mask | arg->return_mask) & ~PM_SCAN_CATEGORIES) + return -EINVAL; + + arg->start = untagged_addr((unsigned long)arg->start); + arg->end = untagged_addr((unsigned long)arg->end); + arg->vec = untagged_addr((unsigned long)arg->vec); + + /* Validate memory pointers */ + if (!IS_ALIGNED(arg->start, PAGE_SIZE)) + return -EINVAL; + if (!access_ok((void __user *)(long)arg->start, arg->end - arg->start)) + return -EFAULT; + if (!arg->vec && arg->vec_len) + return -EINVAL; + if (arg->vec && !access_ok((void __user *)(long)arg->vec, + arg->vec_len * sizeof(struct page_region))) + return -EFAULT; + + /* Fixup default values */ + arg->end = ALIGN(arg->end, PAGE_SIZE); + arg->walk_end = 0; + if (!arg->max_pages) + arg->max_pages = ULONG_MAX; + + return 0; +} + +static int pagemap_scan_writeback_args(struct pm_scan_arg *arg, + unsigned long uargl) +{ + struct pm_scan_arg __user *uarg = (void __user *)uargl; + + if (copy_to_user(&uarg->walk_end, &arg->walk_end, sizeof(arg->walk_end))) + return -EFAULT; + + return 0; +} + +static int pagemap_scan_init_bounce_buffer(struct pagemap_scan_private *p) +{ + if (!p->arg.vec_len) + return 0; + + p->vec_buf_len = min_t(size_t, PAGEMAP_WALK_SIZE >> PAGE_SHIFT, + p->arg.vec_len); + p->vec_buf = kmalloc_array(p->vec_buf_len, sizeof(*p->vec_buf), + GFP_KERNEL); + if (!p->vec_buf) + return -ENOMEM; + + p->vec_buf->start = p->vec_buf->end = 0; + p->vec_out = (struct page_region __user *)(long)p->arg.vec; + + return 0; +} + +static long pagemap_scan_flush_buffer(struct pagemap_scan_private *p) +{ + const struct page_region *buf = p->vec_buf; + long n = p->vec_buf_index; + + if (!p->vec_buf) + return 0; + + if (buf[n].end != buf[n].start) + n++; + + if (!n) + return 0; + + if (copy_to_user(p->vec_out, buf, n * sizeof(*buf))) + return -EFAULT; + + p->arg.vec_len -= n; + p->vec_out += n; + + p->vec_buf_index = 0; + p->vec_buf_len = min_t(size_t, p->vec_buf_len, p->arg.vec_len); + p->vec_buf->start = p->vec_buf->end = 0; + + return n; +} + +static long do_pagemap_scan(struct mm_struct *mm, unsigned long uarg) +{ + struct mmu_notifier_range range; + struct pagemap_scan_private p = {0}; + unsigned long walk_start; + size_t n_ranges_out = 0; + int ret; + + ret = pagemap_scan_get_args(&p.arg, uarg); + if (ret) + return ret; + + p.masks_of_interest = p.arg.category_mask | p.arg.category_anyof_mask | + p.arg.return_mask; + ret = pagemap_scan_init_bounce_buffer(&p); + if (ret) + return ret; + + /* Protection change for the range is going to happen. */ + if (p.arg.flags & PM_SCAN_WP_MATCHING) { + mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, 0, + mm, p.arg.start, p.arg.end); + mmu_notifier_invalidate_range_start(&range); + } + + for (walk_start = p.arg.start; walk_start < p.arg.end; + walk_start = p.arg.walk_end) { + long n_out; + + if (fatal_signal_pending(current)) { + ret = -EINTR; + break; + } + + ret = mmap_read_lock_killable(mm); + if (ret) + break; + ret = walk_page_range(mm, walk_start, p.arg.end, + &pagemap_scan_ops, &p); + mmap_read_unlock(mm); + + n_out = pagemap_scan_flush_buffer(&p); + if (n_out < 0) + ret = n_out; + else + n_ranges_out += n_out; + + if (ret != -ENOSPC) + break; + + if (p.arg.vec_len == 0 || p.found_pages == p.arg.max_pages) + break; + } + + /* ENOSPC signifies early stop (buffer full) from the walk. */ + if (!ret || ret == -ENOSPC) + ret = n_ranges_out; + + /* The walk_end isn't set when ret is zero */ + if (!p.arg.walk_end) + p.arg.walk_end = p.arg.end; + if (pagemap_scan_writeback_args(&p.arg, uarg)) + ret = -EFAULT; + + if (p.arg.flags & PM_SCAN_WP_MATCHING) + mmu_notifier_invalidate_range_end(&range); + + kfree(p.vec_buf); + return ret; +} + +static long do_pagemap_cmd(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct mm_struct *mm = file->private_data; + + switch (cmd) { + case PAGEMAP_SCAN: + return do_pagemap_scan(mm, arg); + + default: + return -EINVAL; + } +} + const struct file_operations proc_pagemap_operations = { .llseek = mem_lseek, /* borrow this */ .read = pagemap_read, .open = pagemap_open, .release = pagemap_release, + .unlocked_ioctl = do_pagemap_cmd, + .compat_ioctl = do_pagemap_cmd, }; #endif /* CONFIG_PROC_PAGE_MONITOR */ diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index e5b9f7e62eeb..205469aa0613 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -280,6 +280,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma, unsigned long cp_flags); bool is_hugetlb_entry_migration(pte_t pte); +bool is_hugetlb_entry_hwpoisoned(pte_t pte); void hugetlb_unshare_all_pmds(struct vm_area_struct *vma); #else /* !CONFIG_HUGETLB_PAGE */ diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index c98df391bfd8..f2dc19f40d05 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -221,6 +221,13 @@ static inline vm_fault_t handle_userfault(struct vm_fault *vmf, return VM_FAULT_SIGBUS; } +static inline long uffd_wp_range(struct vm_area_struct *vma, + unsigned long start, unsigned long len, + bool enable_wp) +{ + return false; +} + static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, struct vm_userfaultfd_ctx vm_ctx) { diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index b7b56871029c..da43810b7485 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -305,4 +305,63 @@ typedef int __bitwise __kernel_rwf_t; #define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\ RWF_APPEND) +/* Pagemap ioctl */ +#define PAGEMAP_SCAN _IOWR('f', 16, struct pm_scan_arg) + +/* Bitmasks provided in pm_scan_args masks and reported in page_region.categories. */ +#define PAGE_IS_WPALLOWED (1 << 0) +#define PAGE_IS_WRITTEN (1 << 1) +#define PAGE_IS_FILE (1 << 2) +#define PAGE_IS_PRESENT (1 << 3) +#define PAGE_IS_SWAPPED (1 << 4) +#define PAGE_IS_PFNZERO (1 << 5) +#define PAGE_IS_HUGE (1 << 6) + +/* + * struct page_region - Page region with flags + * @start: Start of the region + * @end: End of the region (exclusive) + * @categories: PAGE_IS_* category bitmask for the region + */ +struct page_region { + __u64 start; + __u64 end; + __u64 categories; +}; + +/* Flags for PAGEMAP_SCAN ioctl */ +#define PM_SCAN_WP_MATCHING (1 << 0) /* Write protect the pages matched. */ +#define PM_SCAN_CHECK_WPASYNC (1 << 1) /* Abort the scan when a non-WP-enabled page is found. */ + +/* + * struct pm_scan_arg - Pagemap ioctl argument + * @size: Size of the structure + * @flags: Flags for the IOCTL + * @start: Starting address of the region + * @end: Ending address of the region + * @walk_end Address where the scan stopped (written by kernel). + * walk_end == end (address tags cleared) informs that the scan completed on entire range. + * @vec: Address of page_region struct array for output + * @vec_len: Length of the page_region struct array + * @max_pages: Optional limit for number of returned pages (0 = disabled) + * @category_inverted: PAGE_IS_* categories which values match if 0 instead of 1 + * @category_mask: Skip pages for which any category doesn't match + * @category_anyof_mask: Skip pages for which no category matches + * @return_mask: PAGE_IS_* categories that are to be reported in `page_region`s returned + */ +struct pm_scan_arg { + __u64 size; + __u64 flags; + __u64 start; + __u64 end; + __u64 walk_end; + __u64 vec; + __u64 vec_len; + __u64 max_pages; + __u64 category_inverted; + __u64 category_mask; + __u64 category_anyof_mask; + __u64 return_mask; +}; + #endif /* _UAPI_LINUX_FS_H */ diff --git a/mm/hugetlb.c b/mm/hugetlb.c index bc654b36df9f..2878e0e6bac5 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5044,7 +5044,7 @@ bool is_hugetlb_entry_migration(pte_t pte) return false; } -static bool is_hugetlb_entry_hwpoisoned(pte_t pte) +bool is_hugetlb_entry_hwpoisoned(pte_t pte) { swp_entry_t swp; @@ -6266,7 +6266,8 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, } entry = huge_pte_clear_uffd_wp(entry); - set_huge_pte_at(mm, haddr, ptep, entry); + set_huge_pte_at(mm, haddr, ptep, entry, + huge_page_size(hstate_vma(vma))); /* Fallthrough to CoW */ } -- cgit v1.2.3 From ee615d4585cfc305bf6c218a62123c3051f8b4a3 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:25:38 -0700 Subject: shmem: shrink shmem_inode_info: dir_offsets in a union Patch series "shmem,tmpfs: general maintenance". Mostly just cosmetic mods in mm/shmem.c, but the last two enforcing the "size=" limit better. 8/8 goes into percpu counter territory, and could stand alone. This patch (of 8): Shave 32 bytes off (the 64-bit) shmem_inode_info. There was a 4-byte pahole after stop_eviction, better filled by fsflags. And the 24-byte dir_offsets can only be used by directories, whereas shrinklist and swaplist only by shmem_mapping() inodes (regular files or long symlinks): so put those into a union. No change in mm/shmem.c is required for this. Link: https://lkml.kernel.org/r/c7441dc6-f3bb-dd60-c670-9f5cbd9f266@google.com Link: https://lkml.kernel.org/r/86ebb4b-c571-b9e8-27f5-cb82ec50357e@google.com Signed-off-by: Hugh Dickins Reviewed-by: Chuck Lever Reviewed-by: Jan Kara Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Darrick J. Wong Cc: Dave Chinner Cc: Tim Chen Signed-off-by: Andrew Morton --- include/linux/shmem_fs.h | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 6b0c626620f5..2caa6b86106a 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -23,18 +23,22 @@ struct shmem_inode_info { unsigned long flags; unsigned long alloced; /* data pages alloced to file */ unsigned long swapped; /* subtotal assigned to swap */ - pgoff_t fallocend; /* highest fallocate endindex */ - struct list_head shrinklist; /* shrinkable hpage inodes */ - struct list_head swaplist; /* chain of maybes on swap */ + union { + struct offset_ctx dir_offsets; /* stable directory offsets */ + struct { + struct list_head shrinklist; /* shrinkable hpage inodes */ + struct list_head swaplist; /* chain of maybes on swap */ + }; + }; + struct timespec64 i_crtime; /* file creation time */ struct shared_policy policy; /* NUMA memory alloc policy */ struct simple_xattrs xattrs; /* list of xattrs */ + pgoff_t fallocend; /* highest fallocate endindex */ + unsigned int fsflags; /* for FS_IOC_[SG]ETFLAGS */ atomic_t stop_eviction; /* hold when working on inode */ - struct timespec64 i_crtime; /* file creation time */ - unsigned int fsflags; /* flags for FS_IOC_[SG]ETFLAGS */ #ifdef CONFIG_TMPFS_QUOTA struct dquot *i_dquot[MAXQUOTAS]; #endif - struct offset_ctx dir_offsets; /* stable entry offsets */ struct inode vfs_inode; }; -- cgit v1.2.3 From beb9868628445306958fd7b2da1cd369a4a381cc Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:42:45 -0700 Subject: shmem,percpu_counter: add _limited_add(fbc, limit, amount) Percpu counter's compare and add are separate functions: without locking around them (which would defeat their purpose), it has been possible to overflow the intended limit. Imagine all the other CPUs fallocating tmpfs huge pages to the limit, in between this CPU's compare and its add. I have not seen reports of that happening; but tmpfs's recent addition of dquot_alloc_block_nodirty() in between the compare and the add makes it even more likely, and I'd be uncomfortable to leave it unfixed. Introduce percpu_counter_limited_add(fbc, limit, amount) to prevent it. I believe this implementation is correct, and slightly more efficient than the combination of compare and add (taking the lock once rather than twice when nearing full - the last 128MiB of a tmpfs volume on a machine with 128 CPUs and 4KiB pages); but it does beg for a better design - when nearing full, there is no new batching, but the costly percpu counter sum across CPUs still has to be done, while locked. Follow __percpu_counter_sum()'s example, including cpu_dying_mask as well as cpu_online_mask: but shouldn't __percpu_counter_compare() and __percpu_counter_limited_add() then be adding a num_dying_cpus() to num_online_cpus(), when they calculate the maximum which could be held across CPUs? But the times when it matters would be vanishingly rare. Link: https://lkml.kernel.org/r/bb817848-2d19-bcc8-39ca-ea179af0f0b4@google.com Signed-off-by: Hugh Dickins Reviewed-by: Jan Kara Cc: Tim Chen Cc: Dave Chinner Cc: Darrick J. Wong Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Chuck Lever Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- include/linux/percpu_counter.h | 23 ++++++++++++++++++ lib/percpu_counter.c | 53 ++++++++++++++++++++++++++++++++++++++++++ mm/shmem.c | 10 ++++---- 3 files changed, 81 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h index d01351b1526f..8cb7c071bd5c 100644 --- a/include/linux/percpu_counter.h +++ b/include/linux/percpu_counter.h @@ -57,6 +57,8 @@ void percpu_counter_add_batch(struct percpu_counter *fbc, s64 amount, s32 batch); s64 __percpu_counter_sum(struct percpu_counter *fbc); int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch); +bool __percpu_counter_limited_add(struct percpu_counter *fbc, s64 limit, + s64 amount, s32 batch); void percpu_counter_sync(struct percpu_counter *fbc); static inline int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs) @@ -69,6 +71,13 @@ static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount) percpu_counter_add_batch(fbc, amount, percpu_counter_batch); } +static inline bool +percpu_counter_limited_add(struct percpu_counter *fbc, s64 limit, s64 amount) +{ + return __percpu_counter_limited_add(fbc, limit, amount, + percpu_counter_batch); +} + /* * With percpu_counter_add_local() and percpu_counter_sub_local(), counts * are accumulated in local per cpu counter and not in fbc->count until @@ -185,6 +194,20 @@ percpu_counter_add(struct percpu_counter *fbc, s64 amount) local_irq_restore(flags); } +static inline bool +percpu_counter_limited_add(struct percpu_counter *fbc, s64 limit, s64 amount) +{ + unsigned long flags; + s64 count; + + local_irq_save(flags); + count = fbc->count + amount; + if (count <= limit) + fbc->count = count; + local_irq_restore(flags); + return count <= limit; +} + /* non-SMP percpu_counter_add_local is the same with percpu_counter_add */ static inline void percpu_counter_add_local(struct percpu_counter *fbc, s64 amount) diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index 9073430dc865..58a3392f471b 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -278,6 +278,59 @@ int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch) } EXPORT_SYMBOL(__percpu_counter_compare); +/* + * Compare counter, and add amount if the total is within limit. + * Return true if amount was added, false if it would exceed limit. + */ +bool __percpu_counter_limited_add(struct percpu_counter *fbc, + s64 limit, s64 amount, s32 batch) +{ + s64 count; + s64 unknown; + unsigned long flags; + bool good; + + if (amount > limit) + return false; + + local_irq_save(flags); + unknown = batch * num_online_cpus(); + count = __this_cpu_read(*fbc->counters); + + /* Skip taking the lock when safe */ + if (abs(count + amount) <= batch && + fbc->count + unknown <= limit) { + this_cpu_add(*fbc->counters, amount); + local_irq_restore(flags); + return true; + } + + raw_spin_lock(&fbc->lock); + count = fbc->count + amount; + + /* Skip percpu_counter_sum() when safe */ + if (count + unknown > limit) { + s32 *pcount; + int cpu; + + for_each_cpu_or(cpu, cpu_online_mask, cpu_dying_mask) { + pcount = per_cpu_ptr(fbc->counters, cpu); + count += *pcount; + } + } + + good = count <= limit; + if (good) { + count = __this_cpu_read(*fbc->counters); + fbc->count += count + amount; + __this_cpu_sub(*fbc->counters, count); + } + + raw_spin_unlock(&fbc->lock); + local_irq_restore(flags); + return good; +} + static int __init percpu_counter_startup(void) { int ret; diff --git a/mm/shmem.c b/mm/shmem.c index 269cd3c1110f..61b170324e5c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -217,15 +217,15 @@ static int shmem_inode_acct_blocks(struct inode *inode, long pages) might_sleep(); /* when quotas */ if (sbinfo->max_blocks) { - if (percpu_counter_compare(&sbinfo->used_blocks, - sbinfo->max_blocks - pages) > 0) + if (!percpu_counter_limited_add(&sbinfo->used_blocks, + sbinfo->max_blocks, pages)) goto unacct; err = dquot_alloc_block_nodirty(inode, pages); - if (err) + if (err) { + percpu_counter_sub(&sbinfo->used_blocks, pages); goto unacct; - - percpu_counter_add(&sbinfo->used_blocks, pages); + } } else { err = dquot_alloc_block_nodirty(inode, pages); if (err) -- cgit v1.2.3 From 1431996bf9088ee59f8017637ab9a7f89909ae63 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Wed, 11 Oct 2023 21:40:09 -0700 Subject: percpu_counter: extend _limited_add() to negative amounts Though tmpfs does not need it, percpu_counter_limited_add() can be twice as useful if it works sensibly with negative amounts (subs) - typically decrements towards a limit of 0 or nearby: as suggested by Dave Chinner. And in the course of that reworking, skip the percpu counter sum if it is already obvious that the limit would be passed: as suggested by Tim Chen. Extend the comment above __percpu_counter_limited_add(), defining the behaviour with positive and negative amounts, allowing negative limits, but not bothering about overflow beyond S64_MAX. Link: https://lkml.kernel.org/r/8f86083b-c452-95d4-365b-f16a2e4ebcd4@google.com Signed-off-by: Hugh Dickins Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Chuck Lever Cc: Darrick J. Wong Cc: Dave Chinner Cc: Jan Kara Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Tim Chen Signed-off-by: Andrew Morton --- include/linux/percpu_counter.h | 11 +++++++-- lib/percpu_counter.c | 54 +++++++++++++++++++++++++++++++----------- 2 files changed, 49 insertions(+), 16 deletions(-) (limited to 'include/linux') diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h index 8cb7c071bd5c..3a44dd1e33d2 100644 --- a/include/linux/percpu_counter.h +++ b/include/linux/percpu_counter.h @@ -198,14 +198,21 @@ static inline bool percpu_counter_limited_add(struct percpu_counter *fbc, s64 limit, s64 amount) { unsigned long flags; + bool good = false; s64 count; + if (amount == 0) + return true; + local_irq_save(flags); count = fbc->count + amount; - if (count <= limit) + if ((amount > 0 && count <= limit) || + (amount < 0 && count >= limit)) { fbc->count = count; + good = true; + } local_irq_restore(flags); - return count <= limit; + return good; } /* non-SMP percpu_counter_add_local is the same with percpu_counter_add */ diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index 58a3392f471b..44dd133594d4 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -279,8 +279,16 @@ int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch) EXPORT_SYMBOL(__percpu_counter_compare); /* - * Compare counter, and add amount if the total is within limit. - * Return true if amount was added, false if it would exceed limit. + * Compare counter, and add amount if total is: less than or equal to limit if + * amount is positive, or greater than or equal to limit if amount is negative. + * Return true if amount is added, or false if total would be beyond the limit. + * + * Negative limit is allowed, but unusual. + * When negative amounts (subs) are given to percpu_counter_limited_add(), + * the limit would most naturally be 0 - but other limits are also allowed. + * + * Overflow beyond S64_MAX is not allowed for: counter, limit and amount + * are all assumed to be sane (far from S64_MIN and S64_MAX). */ bool __percpu_counter_limited_add(struct percpu_counter *fbc, s64 limit, s64 amount, s32 batch) @@ -288,10 +296,10 @@ bool __percpu_counter_limited_add(struct percpu_counter *fbc, s64 count; s64 unknown; unsigned long flags; - bool good; + bool good = false; - if (amount > limit) - return false; + if (amount == 0) + return true; local_irq_save(flags); unknown = batch * num_online_cpus(); @@ -299,7 +307,8 @@ bool __percpu_counter_limited_add(struct percpu_counter *fbc, /* Skip taking the lock when safe */ if (abs(count + amount) <= batch && - fbc->count + unknown <= limit) { + ((amount > 0 && fbc->count + unknown <= limit) || + (amount < 0 && fbc->count - unknown >= limit))) { this_cpu_add(*fbc->counters, amount); local_irq_restore(flags); return true; @@ -309,7 +318,19 @@ bool __percpu_counter_limited_add(struct percpu_counter *fbc, count = fbc->count + amount; /* Skip percpu_counter_sum() when safe */ - if (count + unknown > limit) { + if (amount > 0) { + if (count - unknown > limit) + goto out; + if (count + unknown <= limit) + good = true; + } else { + if (count + unknown < limit) + goto out; + if (count - unknown >= limit) + good = true; + } + + if (!good) { s32 *pcount; int cpu; @@ -317,15 +338,20 @@ bool __percpu_counter_limited_add(struct percpu_counter *fbc, pcount = per_cpu_ptr(fbc->counters, cpu); count += *pcount; } + if (amount > 0) { + if (count > limit) + goto out; + } else { + if (count < limit) + goto out; + } + good = true; } - good = count <= limit; - if (good) { - count = __this_cpu_read(*fbc->counters); - fbc->count += count + amount; - __this_cpu_sub(*fbc->counters, count); - } - + count = __this_cpu_read(*fbc->counters); + fbc->count += count + amount; + __this_cpu_sub(*fbc->counters, count); +out: raw_spin_unlock(&fbc->lock); local_irq_restore(flags); return good; -- cgit v1.2.3 From 069686255c16a75b6a796e42df47f5af27b496a4 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 2 Oct 2023 16:29:48 +0200 Subject: mm/rmap: convert page_move_anon_rmap() to folio_move_anon_rmap() Let's convert it to consume a folio. [akpm@linux-foundation.org: fix kerneldoc] Link: https://lkml.kernel.org/r/20231002142949.235104-3-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Suren Baghdasaryan Reviewed-by: Vishal Moola (Oracle) Cc: Mike Kravetz Cc: Muchun Song Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- include/linux/rmap.h | 2 +- mm/huge_memory.c | 2 +- mm/hugetlb.c | 2 +- mm/memory.c | 2 +- mm/rmap.c | 16 +++++++--------- 5 files changed, 11 insertions(+), 13 deletions(-) (limited to 'include/linux') diff --git a/include/linux/rmap.h b/include/linux/rmap.h index d22f4d21a11c..b26fe858fd44 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -189,7 +189,7 @@ typedef int __bitwise rmap_t; /* * rmap interfaces called when adding or removing pte of page */ -void page_move_anon_rmap(struct page *, struct vm_area_struct *); +void folio_move_anon_rmap(struct folio *, struct vm_area_struct *); void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long address, rmap_t flags); void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 76ead290f1c8..51a66eb48938 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1376,7 +1376,7 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) if (folio_ref_count(folio) == 1) { pmd_t entry; - page_move_anon_rmap(page, vma); + folio_move_anon_rmap(folio, vma); SetPageAnonExclusive(page); folio_unlock(folio); reuse: diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 35d924f74972..7ad9d2159da4 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5653,7 +5653,7 @@ retry_avoidcopy: */ if (folio_mapcount(old_folio) == 1 && folio_test_anon(old_folio)) { if (!PageAnonExclusive(&old_folio->page)) { - page_move_anon_rmap(&old_folio->page, vma); + folio_move_anon_rmap(old_folio, vma); SetPageAnonExclusive(&old_folio->page); } if (likely(!unshare)) diff --git a/mm/memory.c b/mm/memory.c index 21fba1c9a6c7..6c67828f934c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3480,7 +3480,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) * and the folio is locked, it's dark out, and we're wearing * sunglasses. Hit it. */ - page_move_anon_rmap(vmf->page, vma); + folio_move_anon_rmap(folio, vma); SetPageAnonExclusive(vmf->page); folio_unlock(folio); reuse: diff --git a/mm/rmap.c b/mm/rmap.c index 6f1ea1491118..7a27a2b41802 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1128,19 +1128,17 @@ int folio_total_mapcount(struct folio *folio) } /** - * page_move_anon_rmap - move a page to our anon_vma - * @page: the page to move to our anon_vma - * @vma: the vma the page belongs to + * folio_move_anon_rmap - move a folio to our anon_vma + * @folio: The folio to move to our anon_vma + * @vma: The vma the folio belongs to * - * When a page belongs exclusively to one process after a COW event, - * that page can be moved into the anon_vma that belongs to just that - * process, so the rmap code will not search the parent or sibling - * processes. + * When a folio belongs exclusively to one process after a COW event, + * that folio can be moved into the anon_vma that belongs to just that + * process, so the rmap code will not search the parent or sibling processes. */ -void page_move_anon_rmap(struct page *page, struct vm_area_struct *vma) +void folio_move_anon_rmap(struct folio *folio, struct vm_area_struct *vma) { void *anon_vma = vma->anon_vma; - struct folio *folio = page_folio(page); VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); VM_BUG_ON_VMA(!anon_vma, vma); -- cgit v1.2.3 From c43cfa42541c04a3a94312e39ab81c41ba431277 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Tue, 3 Oct 2023 00:14:51 +0100 Subject: mm: make __access_remote_vm() static Patch series "various improvements to the GUP interface", v2. A series of fixes to simplify and improve the GUP interface with an eye to providing groundwork to future improvements:- * __access_remote_vm() and access_remote_vm() are functionally identical, so make the former static such that in future we can potentially change the external-facing implementation details of this function. * Extend is_valid_gup_args() to cover the missing FOLL_TOUCH case, and simplify things by defining INTERNAL_GUP_FLAGS to check against. * Adjust __get_user_pages_locked() to explicitly treat a failure to pin any pages as an error in all circumstances other than FOLL_NOWAIT being specified, bringing it in line with the nommu implementation of this function. * (With many thanks to Arnd who suggested this in the first instance) Update get_user_page_vma_remote() to explicitly only return a page or an error, simplifying the interface and avoiding the questionable IS_ERR_OR_NULL() pattern. This patch (of 4): access_remote_vm() passes through parameters to __access_remote_vm() directly, so remove the __access_remote_vm() function from mm.h and use access_remote_vm() in the one caller that needs it (ptrace_access_vm()). This allows future adjustments to the GUP-internal __access_remote_vm() function while keeping the access_remote_vm() function stable. Link: https://lkml.kernel.org/r/cover.1696288092.git.lstoakes@gmail.com Link: https://lkml.kernel.org/r/f7877c5039ce1c202a514a8aeeefc5cdd5e32d19.1696288092.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Arnd Bergmann Reviewed-by: David Hildenbrand Reviewed-by: Jason Gunthorpe Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Catalin Marinas Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Hubbard Cc: Mark Rutland Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Richard Cochran Cc: Will Deacon Signed-off-by: Andrew Morton --- include/linux/mm.h | 2 -- kernel/ptrace.c | 2 +- mm/memory.c | 4 ++-- mm/nommu.c | 4 ++-- 4 files changed, 5 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 52c40b3d0813..7b89f7bd420d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2415,8 +2415,6 @@ extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, unsigned int gup_flags); extern int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, unsigned int gup_flags); -extern int __access_remote_vm(struct mm_struct *mm, unsigned long addr, - void *buf, int len, unsigned int gup_flags); long get_user_pages_remote(struct mm_struct *mm, unsigned long start, unsigned long nr_pages, diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 443057bee87c..d8b5e13a2229 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -59,7 +59,7 @@ int ptrace_access_vm(struct task_struct *tsk, unsigned long addr, return 0; } - ret = __access_remote_vm(mm, addr, buf, len, gup_flags); + ret = access_remote_vm(mm, addr, buf, len, gup_flags); mmput(mm); return ret; diff --git a/mm/memory.c b/mm/memory.c index 22784d3b886d..e47c36c0aef0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5791,8 +5791,8 @@ EXPORT_SYMBOL_GPL(generic_access_phys); /* * Access another process' address space as given in mm. */ -int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, - int len, unsigned int gup_flags) +static int __access_remote_vm(struct mm_struct *mm, unsigned long addr, + void *buf, int len, unsigned int gup_flags) { void *old_buf = buf; int write = gup_flags & FOLL_WRITE; diff --git a/mm/nommu.c b/mm/nommu.c index 7f9e9e5a0e12..f9553579389b 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1651,8 +1651,8 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, } EXPORT_SYMBOL(filemap_map_pages); -int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, - int len, unsigned int gup_flags) +static int __access_remote_vm(struct mm_struct *mm, unsigned long addr, + void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; int write = gup_flags & FOLL_WRITE; -- cgit v1.2.3 From 6a1960b8a8773324d870fa32ba68ff3106523a95 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Tue, 3 Oct 2023 00:14:54 +0100 Subject: mm/gup: adapt get_user_page_vma_remote() to never return NULL get_user_pages_remote() will never return 0 except in the case of FOLL_NOWAIT being specified, which we explicitly disallow. This simplifies error handling for the caller and avoids the awkwardness of dealing with both errors and failing to pin. Failing to pin here is an error. Link: https://lkml.kernel.org/r/00319ce292d27b3aae76a0eb220ce3f528187508.1696288092.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Suggested-by: Arnd Bergmann Reviewed-by: Arnd Bergmann Acked-by: Catalin Marinas Reviewed-by: David Hildenbrand Reviewed-by: Jason Gunthorpe Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Hubbard Cc: Mark Rutland Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Richard Cochran Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/arm64/kernel/mte.c | 4 ++-- include/linux/mm.h | 12 +++++++++--- kernel/events/uprobes.c | 4 ++-- mm/memory.c | 3 +-- 4 files changed, 14 insertions(+), 9 deletions(-) (limited to 'include/linux') diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index 4edecaac8f91..8878b392df58 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -411,8 +411,8 @@ static int __access_remote_tags(struct mm_struct *mm, unsigned long addr, struct page *page = get_user_page_vma_remote(mm, addr, gup_flags, &vma); - if (IS_ERR_OR_NULL(page)) { - err = page == NULL ? -EIO : PTR_ERR(page); + if (IS_ERR(page)) { + err = PTR_ERR(page); break; } diff --git a/include/linux/mm.h b/include/linux/mm.h index 7b89f7bd420d..fa608cba041f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2425,6 +2425,9 @@ long pin_user_pages_remote(struct mm_struct *mm, unsigned int gup_flags, struct page **pages, int *locked); +/* + * Retrieves a single page alongside its VMA. Does not support FOLL_NOWAIT. + */ static inline struct page *get_user_page_vma_remote(struct mm_struct *mm, unsigned long addr, int gup_flags, @@ -2432,12 +2435,15 @@ static inline struct page *get_user_page_vma_remote(struct mm_struct *mm, { struct page *page; struct vm_area_struct *vma; - int got = get_user_pages_remote(mm, addr, 1, gup_flags, &page, NULL); + int got; + + if (WARN_ON_ONCE(unlikely(gup_flags & FOLL_NOWAIT))) + return ERR_PTR(-EINVAL); + + got = get_user_pages_remote(mm, addr, 1, gup_flags, &page, NULL); if (got < 0) return ERR_PTR(got); - if (got == 0) - return NULL; vma = vma_lookup(mm, addr); if (WARN_ON_ONCE(!vma)) { diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 3048589e2e85..435aac1d8c27 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -474,8 +474,8 @@ retry: gup_flags |= FOLL_SPLIT_PMD; /* Read the page with vaddr into memory */ old_page = get_user_page_vma_remote(mm, vaddr, gup_flags, &vma); - if (IS_ERR_OR_NULL(old_page)) - return old_page ? PTR_ERR(old_page) : 0; + if (IS_ERR(old_page)) + return PTR_ERR(old_page); ret = verify_opcode(old_page, vaddr, &opcode); if (ret <= 0) diff --git a/mm/memory.c b/mm/memory.c index e47c36c0aef0..1f88e4f6fbf2 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5815,7 +5815,7 @@ static int __access_remote_vm(struct mm_struct *mm, unsigned long addr, struct page *page = get_user_page_vma_remote(mm, addr, gup_flags, &vma); - if (IS_ERR_OR_NULL(page)) { + if (IS_ERR(page)) { /* We might need to expand the stack to access it */ vma = vma_lookup(mm, addr); if (!vma) { @@ -5829,7 +5829,6 @@ static int __access_remote_vm(struct mm_struct *mm, unsigned long addr, continue; } - /* * Check if this is a VM_IO | VM_PFNMAP VMA, which * we can access using slightly different code. -- cgit v1.2.3 From 0b237047d5a72ffe06c0bdf2f4536f669dcd31c9 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Wed, 4 Oct 2023 17:53:03 +0100 Subject: mm: add folio_end_read() Provide a function for filesystems to call when they have finished reading an entire folio. Link: https://lkml.kernel.org/r/20231004165317.1061855-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Albert Ou Cc: Alexander Gordeev Cc: Andreas Dilger Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Geert Uytterhoeven Cc: Heiko Carstens Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Richard Henderson Cc: Sven Schnelle Cc: "Theodore Ts'o" Cc: Thomas Bogendoerfer Cc: Vasily Gorbik Signed-off-by: Andrew Morton --- include/linux/pagemap.h | 1 + mm/filemap.c | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 759b29d9a69a..bcc1ea44b4e8 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -1101,6 +1101,7 @@ static inline void wait_on_page_locked(struct page *page) folio_wait_locked(page_folio(page)); } +void folio_end_read(struct folio *folio, bool success); void wait_on_page_writeback(struct page *page); void folio_wait_writeback(struct folio *folio); int folio_wait_writeback_killable(struct folio *folio); diff --git a/mm/filemap.c b/mm/filemap.c index cd872fbc6086..1ce78c619294 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1525,6 +1525,28 @@ void folio_unlock(struct folio *folio) } EXPORT_SYMBOL(folio_unlock); +/** + * folio_end_read - End read on a folio. + * @folio: The folio. + * @success: True if all reads completed successfully. + * + * When all reads against a folio have completed, filesystems should + * call this function to let the pagecache know that no more reads + * are outstanding. This will unlock the folio and wake up any thread + * sleeping on the lock. The folio will also be marked uptodate if all + * reads succeeded. + * + * Context: May be called from interrupt or process context. May not be + * called from NMI context. + */ +void folio_end_read(struct folio *folio, bool success) +{ + if (likely(success)) + folio_mark_uptodate(folio); + folio_unlock(folio); +} +EXPORT_SYMBOL(folio_end_read); + /** * folio_end_private_2 - Clear PG_private_2 and wake any waiters. * @folio: The folio. -- cgit v1.2.3 From 0410cd844ed0af3db3cb510d877d62c66d26e5cc Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Wed, 4 Oct 2023 17:53:15 +0100 Subject: mm: add folio_xor_flags_has_waiters() Optimise folio_end_read() by setting the uptodate bit at the same time we clear the unlock bit. This saves at least one memory barrier and one write-after-write hazard. Link: https://lkml.kernel.org/r/20231004165317.1061855-16-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Albert Ou Cc: Alexander Gordeev Cc: Andreas Dilger Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Geert Uytterhoeven Cc: Heiko Carstens Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Richard Henderson Cc: Sven Schnelle Cc: "Theodore Ts'o" Cc: Thomas Bogendoerfer Cc: Vasily Gorbik Signed-off-by: Andrew Morton --- include/linux/page-flags.h | 19 +++++++++++++++++++ mm/filemap.c | 14 +++++++++++--- 2 files changed, 30 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 5c02720c53a5..a88e64acebfe 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -692,6 +692,25 @@ TESTPAGEFLAG_FALSE(Ksm, ksm) u64 stable_page_flags(struct page *page); +/** + * folio_xor_flags_has_waiters - Change some folio flags. + * @folio: The folio. + * @mask: Bits set in this word will be changed. + * + * This must only be used for flags which are changed with the folio + * lock held. For example, it is unsafe to use for PG_dirty as that + * can be set without the folio lock held. It can also only be used + * on flags which are in the range 0-6 as some of the implementations + * only affect those bits. + * + * Return: Whether there are tasks waiting on the folio. + */ +static inline bool folio_xor_flags_has_waiters(struct folio *folio, + unsigned long mask) +{ + return xor_unlock_is_negative_byte(mask, folio_flags(folio, 0)); +} + /** * folio_test_uptodate - Is this folio up to date? * @folio: The folio. diff --git a/mm/filemap.c b/mm/filemap.c index 458377e9a184..e9c636f57777 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1497,7 +1497,7 @@ void folio_unlock(struct folio *folio) BUILD_BUG_ON(PG_waiters != 7); BUILD_BUG_ON(PG_locked > 7); VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); - if (xor_unlock_is_negative_byte(1 << PG_locked, folio_flags(folio, 0))) + if (folio_xor_flags_has_waiters(folio, 1 << PG_locked)) folio_wake_bit(folio, PG_locked); } EXPORT_SYMBOL(folio_unlock); @@ -1518,9 +1518,17 @@ EXPORT_SYMBOL(folio_unlock); */ void folio_end_read(struct folio *folio, bool success) { + unsigned long mask = 1 << PG_locked; + + /* Must be in bottom byte for x86 to work */ + BUILD_BUG_ON(PG_uptodate > 7); + VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); + VM_BUG_ON_FOLIO(folio_test_uptodate(folio), folio); + if (likely(success)) - folio_mark_uptodate(folio); - folio_unlock(folio); + mask |= 1 << PG_uptodate; + if (folio_xor_flags_has_waiters(folio, mask)) + folio_wake_bit(folio, PG_locked); } EXPORT_SYMBOL(folio_end_read); -- cgit v1.2.3 From 59838b2566f6d03099743675a2e0f425813078c6 Mon Sep 17 00:00:00 2001 From: Frank van der Linden Date: Wed, 4 Oct 2023 15:32:48 +0000 Subject: mm, hugetlb: remove HUGETLB_CGROUP_MIN_ORDER Originally, hugetlb_cgroup was the only hugetlb user of tail page structure fields. So, the code defined and checked against HUGETLB_CGROUP_MIN_ORDER to make sure pages weren't too small to use. However, by now, tail page #2 is used to store hugetlb hwpoison and subpool information as well. In other words, without that tail page hugetlb doesn't work. Acknowledge this fact by getting rid of HUGETLB_CGROUP_MIN_ORDER and checks against it. Instead, just check for the minimum viable page order at hstate creation time. Link: https://lkml.kernel.org/r/20231004153248.3842997-1-fvdl@google.com Signed-off-by: Frank van der Linden Reviewed-by: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton --- include/linux/hugetlb_cgroup.h | 11 ----------- mm/hugetlb.c | 2 +- mm/hugetlb_cgroup.c | 20 ++------------------ 3 files changed, 3 insertions(+), 30 deletions(-) (limited to 'include/linux') diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h index 3d82d91f49ac..e5d64b8b59c2 100644 --- a/include/linux/hugetlb_cgroup.h +++ b/include/linux/hugetlb_cgroup.h @@ -22,13 +22,6 @@ struct resv_map; struct file_region; #ifdef CONFIG_CGROUP_HUGETLB -/* - * Minimum page order trackable by hugetlb cgroup. - * At least 3 pages are necessary for all the tracking information. - * The second tail page contains all of the hugetlb-specific fields. - */ -#define HUGETLB_CGROUP_MIN_ORDER order_base_2(__NR_USED_SUBPAGE) - enum hugetlb_memory_event { HUGETLB_MAX, HUGETLB_NR_MEMORY_EVENTS, @@ -68,8 +61,6 @@ static inline struct hugetlb_cgroup * __hugetlb_cgroup_from_folio(struct folio *folio, bool rsvd) { VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio); - if (folio_order(folio) < HUGETLB_CGROUP_MIN_ORDER) - return NULL; if (rsvd) return folio->_hugetlb_cgroup_rsvd; else @@ -91,8 +82,6 @@ static inline void __set_hugetlb_cgroup(struct folio *folio, struct hugetlb_cgroup *h_cg, bool rsvd) { VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio); - if (folio_order(folio) < HUGETLB_CGROUP_MIN_ORDER) - return; if (rsvd) folio->_hugetlb_cgroup_rsvd = h_cg; else diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 7ad9d2159da4..e2b1c417b90a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4361,7 +4361,7 @@ void __init hugetlb_add_hstate(unsigned int order) return; } BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); - BUG_ON(order == 0); + BUG_ON(order < order_base_2(__NR_USED_SUBPAGE)); h = &hstates[hugetlb_max_hstate++]; mutex_init(&h->resize_lock); h->order = order; diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index dedd2edb076e..aa4486bd3904 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -262,12 +262,6 @@ static int __hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, if (hugetlb_cgroup_disabled()) goto done; - /* - * We don't charge any cgroup if the compound page have less - * than 3 pages. - */ - if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER) - goto done; again: rcu_read_lock(); h_cg = hugetlb_cgroup_from_task(current); @@ -397,9 +391,6 @@ static void __hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, if (hugetlb_cgroup_disabled() || !h_cg) return; - if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER) - return; - page_counter_uncharge(__hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd), nr_pages); @@ -869,15 +860,8 @@ void __init hugetlb_cgroup_file_init(void) { struct hstate *h; - for_each_hstate(h) { - /* - * Add cgroup control files only if the huge page consists - * of more than two normal pages. This is because we use - * page[2].private for storing cgroup details. - */ - if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER) - __hugetlb_cgroup_file_init(hstate_index(h)); - } + for_each_hstate(h) + __hugetlb_cgroup_file_init(hstate_index(h)); } /* -- cgit v1.2.3 From 4b569387c0d566db288e7c3e1b484b43df797bdb Mon Sep 17 00:00:00 2001 From: Nhat Pham Date: Fri, 6 Oct 2023 11:46:26 -0700 Subject: memcontrol: add helpers for hugetlb memcg accounting Patch series "hugetlb memcg accounting", v4. Currently, hugetlb memory usage is not acounted for in the memory controller, which could lead to memory overprotection for cgroups with hugetlb-backed memory. This has been observed in our production system. For instance, here is one of our usecases: suppose there are two 32G containers. The machine is booted with hugetlb_cma=6G, and each container may or may not use up to 3 gigantic page, depending on the workload within it. The rest is anon, cache, slab, etc. We can set the hugetlb cgroup limit of each cgroup to 3G to enforce hugetlb fairness. But it is very difficult to configure memory.max to keep overall consumption, including anon, cache, slab etcetera fair. What we have had to resort to is to constantly poll hugetlb usage and readjust memory.max. Similar procedure is done to other memory limits (memory.low for e.g). However, this is rather cumbersome and buggy. Furthermore, when there is a delay in memory limits correction, (for e.g when hugetlb usage changes within consecutive runs of the userspace agent), the system could be in an over/underprotected state. This patch series rectifies this issue by charging the memcg when the hugetlb folio is allocated, and uncharging when the folio is freed. In addition, a new selftest is added to demonstrate and verify this new behavior. This patch (of 4): This patch exposes charge committing and cancelling as parts of the memory controller interface. These functionalities are useful when the try_charge() and commit_charge() stages have to be separated by other actions in between (which can fail). One such example is the new hugetlb accounting behavior in the following patch. The patch also adds a helper function to obtain a reference to the current task's memcg. Link: https://lkml.kernel.org/r/20231006184629.155543-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20231006184629.155543-2-nphamcs@gmail.com Signed-off-by: Nhat Pham Acked-by: Michal Hocko Acked-by: Johannes Weiner Cc: Frank van der Linden Cc: Mike Kravetz Cc: Muchun Song Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Shuah Khan Cc: Tejun heo Cc: Yosry Ahmed Cc: Zefan Li Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 21 +++++++++++++++++ mm/memcontrol.c | 59 ++++++++++++++++++++++++++++++++++++---------- 2 files changed, 68 insertions(+), 12 deletions(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index c6029aeaa268..bea3d997b076 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -652,6 +652,8 @@ static inline bool mem_cgroup_below_min(struct mem_cgroup *target, page_counter_read(&memcg->memory); } +void mem_cgroup_commit_charge(struct folio *folio, struct mem_cgroup *memcg); + int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp); /** @@ -703,6 +705,8 @@ static inline void mem_cgroup_uncharge_list(struct list_head *page_list) __mem_cgroup_uncharge_list(page_list); } +void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages); + void mem_cgroup_migrate(struct folio *old, struct folio *new); /** @@ -759,6 +763,8 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p); struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm); +struct mem_cgroup *get_mem_cgroup_from_current(void); + struct lruvec *folio_lruvec_lock(struct folio *folio); struct lruvec *folio_lruvec_lock_irq(struct folio *folio); struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio, @@ -1239,6 +1245,11 @@ static inline bool mem_cgroup_below_min(struct mem_cgroup *target, return false; } +static inline void mem_cgroup_commit_charge(struct folio *folio, + struct mem_cgroup *memcg) +{ +} + static inline int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp) { @@ -1263,6 +1274,11 @@ static inline void mem_cgroup_uncharge_list(struct list_head *page_list) { } +static inline void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, + unsigned int nr_pages) +{ +} + static inline void mem_cgroup_migrate(struct folio *old, struct folio *new) { } @@ -1300,6 +1316,11 @@ static inline struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) return NULL; } +static inline struct mem_cgroup *get_mem_cgroup_from_current(void) +{ + return NULL; +} + static inline struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css) { diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 8539f2037168..b3e40a59f732 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1099,6 +1099,27 @@ static __always_inline bool memcg_kmem_bypass(void) return false; } +/** + * get_mem_cgroup_from_current - Obtain a reference on current task's memcg. + */ +struct mem_cgroup *get_mem_cgroup_from_current(void) +{ + struct mem_cgroup *memcg; + + if (mem_cgroup_disabled()) + return NULL; + +again: + rcu_read_lock(); + memcg = mem_cgroup_from_task(current); + if (!css_tryget(&memcg->css)) { + rcu_read_unlock(); + goto again; + } + rcu_read_unlock(); + return memcg; +} + /** * mem_cgroup_iter - iterate over memory cgroup hierarchy * @root: hierarchy root @@ -2873,7 +2894,12 @@ static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, return try_charge_memcg(memcg, gfp_mask, nr_pages); } -static inline void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) +/** + * mem_cgroup_cancel_charge() - cancel an uncommitted try_charge() call. + * @memcg: memcg previously charged. + * @nr_pages: number of pages previously charged. + */ +void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) { if (mem_cgroup_is_root(memcg)) return; @@ -2898,6 +2924,22 @@ static void commit_charge(struct folio *folio, struct mem_cgroup *memcg) folio->memcg_data = (unsigned long)memcg; } +/** + * mem_cgroup_commit_charge - commit a previously successful try_charge(). + * @folio: folio to commit the charge to. + * @memcg: memcg previously charged. + */ +void mem_cgroup_commit_charge(struct folio *folio, struct mem_cgroup *memcg) +{ + css_get(&memcg->css); + commit_charge(folio, memcg); + + local_irq_disable(); + mem_cgroup_charge_statistics(memcg, folio_nr_pages(folio)); + memcg_check_events(memcg, folio_nid(folio)); + local_irq_enable(); +} + #ifdef CONFIG_MEMCG_KMEM /* * The allocated objcg pointers array is not accounted directly. @@ -6116,7 +6158,7 @@ static void __mem_cgroup_clear_mc(void) /* we must uncharge all the leftover precharges from mc.to */ if (mc.precharge) { - cancel_charge(mc.to, mc.precharge); + mem_cgroup_cancel_charge(mc.to, mc.precharge); mc.precharge = 0; } /* @@ -6124,7 +6166,7 @@ static void __mem_cgroup_clear_mc(void) * we must uncharge here. */ if (mc.moved_charge) { - cancel_charge(mc.from, mc.moved_charge); + mem_cgroup_cancel_charge(mc.from, mc.moved_charge); mc.moved_charge = 0; } /* we must fixup refcnts and charges */ @@ -7031,20 +7073,13 @@ void mem_cgroup_calculate_protection(struct mem_cgroup *root, static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg, gfp_t gfp) { - long nr_pages = folio_nr_pages(folio); int ret; - ret = try_charge(memcg, gfp, nr_pages); + ret = try_charge(memcg, gfp, folio_nr_pages(folio)); if (ret) goto out; - css_get(&memcg->css); - commit_charge(folio, memcg); - - local_irq_disable(); - mem_cgroup_charge_statistics(memcg, nr_pages); - memcg_check_events(memcg, folio_nid(folio)); - local_irq_enable(); + mem_cgroup_commit_charge(folio, memcg); out: return ret; } -- cgit v1.2.3 From 85ce2c517ade0d51b7ad95f2e88be9bbe294379a Mon Sep 17 00:00:00 2001 From: Nhat Pham Date: Fri, 6 Oct 2023 11:46:27 -0700 Subject: memcontrol: only transfer the memcg data for migration For most migration use cases, only transfer the memcg data from the old folio to the new folio, and clear the old folio's memcg data. No charging and uncharging will be done. This shaves off some work on the migration path, and avoids the temporary double charging of a folio during its migration. The only exception is replace_page_cache_folio(), which will use the old mem_cgroup_migrate() (now renamed to mem_cgroup_replace_folio). In that context, the isolation of the old page isn't quite as thorough as with migration, so we cannot use our new implementation directly. This patch is the result of the following discussion on the new hugetlb memcg accounting behavior: https://lore.kernel.org/lkml/20231003171329.GB314430@monkey/ Link: https://lkml.kernel.org/r/20231006184629.155543-3-nphamcs@gmail.com Signed-off-by: Nhat Pham Suggested-by: Johannes Weiner Acked-by: Johannes Weiner Cc: Frank van der Linden Cc: Michal Hocko Cc: Mike Kravetz Cc: Muchun Song Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Shuah Khan Cc: Tejun heo Cc: Yosry Ahmed Cc: Zefan Li Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 7 +++++++ mm/filemap.c | 2 +- mm/memcontrol.c | 40 +++++++++++++++++++++++++++++++++++++--- 3 files changed, 45 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index bea3d997b076..a3fce570122e 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -707,6 +707,8 @@ static inline void mem_cgroup_uncharge_list(struct list_head *page_list) void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages); +void mem_cgroup_replace_folio(struct folio *old, struct folio *new); + void mem_cgroup_migrate(struct folio *old, struct folio *new); /** @@ -1279,6 +1281,11 @@ static inline void mem_cgroup_cancel_charge(struct mem_cgroup *memcg, { } +static inline void mem_cgroup_replace_folio(struct folio *old, + struct folio *new) +{ +} + static inline void mem_cgroup_migrate(struct folio *old, struct folio *new) { } diff --git a/mm/filemap.c b/mm/filemap.c index b04ba896aac9..48cd16c54e86 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -816,7 +816,7 @@ void replace_page_cache_folio(struct folio *old, struct folio *new) new->mapping = mapping; new->index = offset; - mem_cgroup_migrate(old, new); + mem_cgroup_replace_folio(old, new); xas_lock_irq(&xas); xas_store(&xas, new); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b3e40a59f732..135d6637afe5 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -7292,16 +7292,17 @@ void __mem_cgroup_uncharge_list(struct list_head *page_list) } /** - * mem_cgroup_migrate - Charge a folio's replacement. + * mem_cgroup_replace_folio - Charge a folio's replacement. * @old: Currently circulating folio. * @new: Replacement folio. * * Charge @new as a replacement folio for @old. @old will - * be uncharged upon free. + * be uncharged upon free. This is only used by the page cache + * (in replace_page_cache_folio()). * * Both folios must be locked, @new->mapping must be set up. */ -void mem_cgroup_migrate(struct folio *old, struct folio *new) +void mem_cgroup_replace_folio(struct folio *old, struct folio *new) { struct mem_cgroup *memcg; long nr_pages = folio_nr_pages(new); @@ -7340,6 +7341,39 @@ void mem_cgroup_migrate(struct folio *old, struct folio *new) local_irq_restore(flags); } +/** + * mem_cgroup_migrate - Transfer the memcg data from the old to the new folio. + * @old: Currently circulating folio. + * @new: Replacement folio. + * + * Transfer the memcg data from the old folio to the new folio for migration. + * The old folio's data info will be cleared. Note that the memory counters + * will remain unchanged throughout the process. + * + * Both folios must be locked, @new->mapping must be set up. + */ +void mem_cgroup_migrate(struct folio *old, struct folio *new) +{ + struct mem_cgroup *memcg; + + VM_BUG_ON_FOLIO(!folio_test_locked(old), old); + VM_BUG_ON_FOLIO(!folio_test_locked(new), new); + VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new); + VM_BUG_ON_FOLIO(folio_nr_pages(old) != folio_nr_pages(new), new); + + if (mem_cgroup_disabled()) + return; + + memcg = folio_memcg(old); + VM_WARN_ON_ONCE_FOLIO(!memcg, old); + if (!memcg) + return; + + /* Transfer the charge and the css ref */ + commit_charge(new, memcg); + old->memcg_data = 0; +} + DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key); EXPORT_SYMBOL(memcg_sockets_enabled_key); -- cgit v1.2.3 From 8cba9576df601c384abd334a503c3f6e1e29eefb Mon Sep 17 00:00:00 2001 From: Nhat Pham Date: Fri, 6 Oct 2023 11:46:28 -0700 Subject: hugetlb: memcg: account hugetlb-backed memory in memory controller Currently, hugetlb memory usage is not acounted for in the memory controller, which could lead to memory overprotection for cgroups with hugetlb-backed memory. This has been observed in our production system. For instance, here is one of our usecases: suppose there are two 32G containers. The machine is booted with hugetlb_cma=6G, and each container may or may not use up to 3 gigantic page, depending on the workload within it. The rest is anon, cache, slab, etc. We can set the hugetlb cgroup limit of each cgroup to 3G to enforce hugetlb fairness. But it is very difficult to configure memory.max to keep overall consumption, including anon, cache, slab etc. fair. What we have had to resort to is to constantly poll hugetlb usage and readjust memory.max. Similar procedure is done to other memory limits (memory.low for e.g). However, this is rather cumbersome and buggy. Furthermore, when there is a delay in memory limits correction, (for e.g when hugetlb usage changes within consecutive runs of the userspace agent), the system could be in an over/underprotected state. This patch rectifies this issue by charging the memcg when the hugetlb folio is utilized, and uncharging when the folio is freed (analogous to the hugetlb controller). Note that we do not charge when the folio is allocated to the hugetlb pool, because at this point it is not owned by any memcg. Some caveats to consider: * This feature is only available on cgroup v2. * There is no hugetlb pool management involved in the memory controller. As stated above, hugetlb folios are only charged towards the memory controller when it is used. Host overcommit management has to consider it when configuring hard limits. * Failure to charge towards the memcg results in SIGBUS. This could happen even if the hugetlb pool still has pages (but the cgroup limit is hit and reclaim attempt fails). * When this feature is enabled, hugetlb pages contribute to memory reclaim protection. low, min limits tuning must take into account hugetlb memory. * Hugetlb pages utilized while this option is not selected will not be tracked by the memory controller (even if cgroup v2 is remounted later on). Link: https://lkml.kernel.org/r/20231006184629.155543-4-nphamcs@gmail.com Signed-off-by: Nhat Pham Acked-by: Johannes Weiner Cc: Frank van der Linden Cc: Michal Hocko Cc: Mike Kravetz Cc: Muchun Song Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Shuah Khan Cc: Tejun heo Cc: Yosry Ahmed Cc: Zefan Li Signed-off-by: Andrew Morton --- Documentation/admin-guide/cgroup-v2.rst | 29 +++++++++++++++++++++++ include/linux/cgroup-defs.h | 5 ++++ include/linux/memcontrol.h | 9 +++++++ kernel/cgroup/cgroup.c | 15 +++++++++++- mm/hugetlb.c | 35 +++++++++++++++++++++------ mm/memcontrol.c | 42 ++++++++++++++++++++++++++++++++- mm/migrate.c | 3 +-- 7 files changed, 127 insertions(+), 11 deletions(-) (limited to 'include/linux') diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 622a7f28db1f..606b2e0eac4b 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -210,6 +210,35 @@ cgroup v2 currently supports the following mount options. relying on the original semantics (e.g. specifying bogusly high 'bypass' protection values at higher tree levels). + memory_hugetlb_accounting + Count HugeTLB memory usage towards the cgroup's overall + memory usage for the memory controller (for the purpose of + statistics reporting and memory protetion). This is a new + behavior that could regress existing setups, so it must be + explicitly opted in with this mount option. + + A few caveats to keep in mind: + + * There is no HugeTLB pool management involved in the memory + controller. The pre-allocated pool does not belong to anyone. + Specifically, when a new HugeTLB folio is allocated to + the pool, it is not accounted for from the perspective of the + memory controller. It is only charged to a cgroup when it is + actually used (for e.g at page fault time). Host memory + overcommit management has to consider this when configuring + hard limits. In general, HugeTLB pool management should be + done via other mechanisms (such as the HugeTLB controller). + * Failure to charge a HugeTLB folio to the memory controller + results in SIGBUS. This could happen even if the HugeTLB pool + still has pages available (but the cgroup limit is hit and + reclaim attempt fails). + * Charging HugeTLB memory towards the memory controller affects + memory protection and reclaim dynamics. Any userspace tuning + (of low, min limits for e.g) needs to take this into account. + * HugeTLB pages utilized while this option is not selected + will not be tracked by the memory controller (even if cgroup + v2 is remounted later on). + Organizing Processes and Threads -------------------------------- diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index f1b3151ac30b..8641f4320c98 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -115,6 +115,11 @@ enum { * Enable recursive subtree protection */ CGRP_ROOT_MEMORY_RECURSIVE_PROT = (1 << 18), + + /* + * Enable hugetlb accounting for the memory controller. + */ + CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING = (1 << 19), }; /* cftype->flags */ diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index a3fce570122e..6674c12725d5 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -678,6 +678,9 @@ static inline int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, return __mem_cgroup_charge(folio, mm, gfp); } +int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp, + long nr_pages); + int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm, gfp_t gfp, swp_entry_t entry); void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry); @@ -1258,6 +1261,12 @@ static inline int mem_cgroup_charge(struct folio *folio, return 0; } +static inline int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, + gfp_t gfp, long nr_pages) +{ + return 0; +} + static inline int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm, gfp_t gfp, swp_entry_t entry) { diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 1fb7f562289d..f11488b18ceb 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1902,6 +1902,7 @@ enum cgroup2_param { Opt_favordynmods, Opt_memory_localevents, Opt_memory_recursiveprot, + Opt_memory_hugetlb_accounting, nr__cgroup2_params }; @@ -1910,6 +1911,7 @@ static const struct fs_parameter_spec cgroup2_fs_parameters[] = { fsparam_flag("favordynmods", Opt_favordynmods), fsparam_flag("memory_localevents", Opt_memory_localevents), fsparam_flag("memory_recursiveprot", Opt_memory_recursiveprot), + fsparam_flag("memory_hugetlb_accounting", Opt_memory_hugetlb_accounting), {} }; @@ -1936,6 +1938,9 @@ static int cgroup2_parse_param(struct fs_context *fc, struct fs_parameter *param case Opt_memory_recursiveprot: ctx->flags |= CGRP_ROOT_MEMORY_RECURSIVE_PROT; return 0; + case Opt_memory_hugetlb_accounting: + ctx->flags |= CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING; + return 0; } return -EINVAL; } @@ -1960,6 +1965,11 @@ static void apply_cgroup_root_flags(unsigned int root_flags) cgrp_dfl_root.flags |= CGRP_ROOT_MEMORY_RECURSIVE_PROT; else cgrp_dfl_root.flags &= ~CGRP_ROOT_MEMORY_RECURSIVE_PROT; + + if (root_flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING) + cgrp_dfl_root.flags |= CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING; + else + cgrp_dfl_root.flags &= ~CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING; } } @@ -1973,6 +1983,8 @@ static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root seq_puts(seq, ",memory_localevents"); if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT) seq_puts(seq, ",memory_recursiveprot"); + if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING) + seq_puts(seq, ",memory_hugetlb_accounting"); return 0; } @@ -7050,7 +7062,8 @@ static ssize_t features_show(struct kobject *kobj, struct kobj_attribute *attr, "nsdelegate\n" "favordynmods\n" "memory_localevents\n" - "memory_recursiveprot\n"); + "memory_recursiveprot\n" + "memory_hugetlb_accounting\n"); } static struct kobj_attribute cgroup_features_attr = __ATTR_RO(features); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index e2b1c417b90a..da6f85b7db88 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1927,6 +1927,7 @@ void free_huge_folio(struct folio *folio) pages_per_huge_page(h), folio); hugetlb_cgroup_uncharge_folio_rsvd(hstate_index(h), pages_per_huge_page(h), folio); + mem_cgroup_uncharge(folio); if (restore_reserve) h->resv_huge_pages++; @@ -3026,11 +3027,20 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, struct hugepage_subpool *spool = subpool_vma(vma); struct hstate *h = hstate_vma(vma); struct folio *folio; - long map_chg, map_commit; + long map_chg, map_commit, nr_pages = pages_per_huge_page(h); long gbl_chg; - int ret, idx; + int memcg_charge_ret, ret, idx; struct hugetlb_cgroup *h_cg = NULL; + struct mem_cgroup *memcg; bool deferred_reserve; + gfp_t gfp = htlb_alloc_mask(h) | __GFP_RETRY_MAYFAIL; + + memcg = get_mem_cgroup_from_current(); + memcg_charge_ret = mem_cgroup_hugetlb_try_charge(memcg, gfp, nr_pages); + if (memcg_charge_ret == -ENOMEM) { + mem_cgroup_put(memcg); + return ERR_PTR(-ENOMEM); + } idx = hstate_index(h); /* @@ -3039,8 +3049,12 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, * code of zero indicates a reservation exists (no change). */ map_chg = gbl_chg = vma_needs_reservation(h, vma, addr); - if (map_chg < 0) + if (map_chg < 0) { + if (!memcg_charge_ret) + mem_cgroup_cancel_charge(memcg, nr_pages); + mem_cgroup_put(memcg); return ERR_PTR(-ENOMEM); + } /* * Processes that did not create the mapping will have no @@ -3051,10 +3065,8 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, */ if (map_chg || avoid_reserve) { gbl_chg = hugepage_subpool_get_pages(spool, 1); - if (gbl_chg < 0) { - vma_end_reservation(h, vma, addr); - return ERR_PTR(-ENOSPC); - } + if (gbl_chg < 0) + goto out_end_reservation; /* * Even though there was no reservation in the region/reserve @@ -3136,6 +3148,11 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, hugetlb_cgroup_uncharge_folio_rsvd(hstate_index(h), pages_per_huge_page(h), folio); } + + if (!memcg_charge_ret) + mem_cgroup_commit_charge(folio, memcg); + mem_cgroup_put(memcg); + return folio; out_uncharge_cgroup: @@ -3147,7 +3164,11 @@ out_uncharge_cgroup_reservation: out_subpool_put: if (map_chg || avoid_reserve) hugepage_subpool_put_pages(spool, 1); +out_end_reservation: vma_end_reservation(h, vma, addr); + if (!memcg_charge_ret) + mem_cgroup_cancel_charge(memcg, nr_pages); + mem_cgroup_put(memcg); return ERR_PTR(-ENOSPC); } diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 135d6637afe5..a86e7b445800 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -7096,6 +7096,41 @@ int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp) return ret; } +/** + * mem_cgroup_hugetlb_try_charge - try to charge the memcg for a hugetlb folio + * @memcg: memcg to charge. + * @gfp: reclaim mode. + * @nr_pages: number of pages to charge. + * + * This function is called when allocating a huge page folio to determine if + * the memcg has the capacity for it. It does not commit the charge yet, + * as the hugetlb folio itself has not been obtained from the hugetlb pool. + * + * Once we have obtained the hugetlb folio, we can call + * mem_cgroup_commit_charge() to commit the charge. If we fail to obtain the + * folio, we should instead call mem_cgroup_cancel_charge() to undo the effect + * of try_charge(). + * + * Returns 0 on success. Otherwise, an error code is returned. + */ +int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp, + long nr_pages) +{ + /* + * If hugetlb memcg charging is not enabled, do not fail hugetlb allocation, + * but do not attempt to commit charge later (or cancel on error) either. + */ + if (mem_cgroup_disabled() || !memcg || + !cgroup_subsys_on_dfl(memory_cgrp_subsys) || + !(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING)) + return -EOPNOTSUPP; + + if (try_charge(memcg, gfp, nr_pages)) + return -ENOMEM; + + return 0; +} + /** * mem_cgroup_swapin_charge_folio - Charge a newly allocated folio for swapin. * @folio: folio to charge. @@ -7365,7 +7400,12 @@ void mem_cgroup_migrate(struct folio *old, struct folio *new) return; memcg = folio_memcg(old); - VM_WARN_ON_ONCE_FOLIO(!memcg, old); + /* + * Note that it is normal to see !memcg for a hugetlb folio. + * For e.g, itt could have been allocated when memory_hugetlb_accounting + * was not selected. + */ + VM_WARN_ON_ONCE_FOLIO(!folio_test_hugetlb(old) && !memcg, old); if (!memcg) return; diff --git a/mm/migrate.c b/mm/migrate.c index 9d9eee5322d1..c602bf6dec97 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -633,8 +633,7 @@ void folio_migrate_flags(struct folio *newfolio, struct folio *folio) folio_copy_owner(newfolio, folio); - if (!folio_test_hugetlb(folio)) - mem_cgroup_migrate(folio, newfolio); + mem_cgroup_migrate(folio, newfolio); } EXPORT_SYMBOL(folio_migrate_flags); -- cgit v1.2.3 From f04eba134e598d4a5af2eeecff0562df5042cbfc Mon Sep 17 00:00:00 2001 From: Lucy Mielke Date: Fri, 6 Oct 2023 22:30:51 +0200 Subject: mm: add printf attribute to shrinker_debugfs_name_alloc This fixes a compiler warning when compiling an allyesconfig with W=1: mm/internal.h:1235:9: error: function might be a candidate for `gnu_printf' format attribute [-Werror=suggest-attribute=format] [akpm@linux-foundation.org: fix shrinker_alloc() as welll per Qi Zheng] Link: https://lkml.kernel.org/r/822387b7-4895-4e64-5806-0f56b5d6c447@bytedance.com Link: https://lkml.kernel.org/r/ZSBue-3kM6gI6jCr@mainframe Fixes: c42d50aefd17 ("mm: shrinker: add infrastructure for dynamically allocating shrinker") Signed-off-by: Lucy Mielke Cc: Qi Zheng Signed-off-by: Andrew Morton --- include/linux/shrinker.h | 1 + mm/internal.h | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index e4f93120e0ab..1a00be90d93a 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -131,6 +131,7 @@ struct shrinker { */ #define SHRINKER_NONSLAB BIT(4) +__printf(2, 3) struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...); void shrinker_register(struct shrinker *shrinker); void shrinker_free(struct shrinker *shrinker); diff --git a/mm/internal.h b/mm/internal.h index 2b79da9deb64..d1f7a3c612fe 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1219,8 +1219,8 @@ unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg, int priority); #ifdef CONFIG_SHRINKER_DEBUG -static inline int shrinker_debugfs_name_alloc(struct shrinker *shrinker, - const char *fmt, va_list ap) +static inline __printf(2, 0) int shrinker_debugfs_name_alloc( + struct shrinker *shrinker, const char *fmt, va_list ap) { shrinker->name = kvasprintf_const(GFP_KERNEL, fmt, ap); -- cgit v1.2.3 From 37acade0ce8938f00d6979bd02b8043b5b7089ae Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Tue, 10 Oct 2023 04:58:29 +0100 Subject: sched: remove wait bookmarks There are no users of wait bookmarks left, so simplify the wait code by removing them. Link: https://lkml.kernel.org/r/20231010035829.544242-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Ingo Molnar Cc: Benjamin Segall Cc: Bin Lai Cc: Daniel Bristot de Oliveira Cc: Dietmar Eggemann Cc: Ingo Molnar Cc: Juri Lelli Cc: Mel Gorman Cc: Peter Zijlstra Cc: Steven Rostedt (Google) Cc: Valentin Schneider Cc: Vincent Guittot Signed-off-by: Andrew Morton --- include/linux/wait.h | 9 +++----- kernel/sched/wait.c | 60 +++++++++------------------------------------------- 2 files changed, 13 insertions(+), 56 deletions(-) (limited to 'include/linux') diff --git a/include/linux/wait.h b/include/linux/wait.h index 5ec7739400f4..3473b663176f 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -19,10 +19,9 @@ int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int /* wait_queue_entry::flags */ #define WQ_FLAG_EXCLUSIVE 0x01 #define WQ_FLAG_WOKEN 0x02 -#define WQ_FLAG_BOOKMARK 0x04 -#define WQ_FLAG_CUSTOM 0x08 -#define WQ_FLAG_DONE 0x10 -#define WQ_FLAG_PRIORITY 0x20 +#define WQ_FLAG_CUSTOM 0x04 +#define WQ_FLAG_DONE 0x08 +#define WQ_FLAG_PRIORITY 0x10 /* * A single wait-queue entry structure: @@ -212,8 +211,6 @@ __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq int __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key); void __wake_up_on_current_cpu(struct wait_queue_head *wq_head, unsigned int mode, void *key); void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key); -void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head, - unsigned int mode, void *key, wait_queue_entry_t *bookmark); void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key); void __wake_up_locked_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key); void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr); diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 802d98cf2de3..51e38f5f4701 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -57,13 +57,6 @@ void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry } EXPORT_SYMBOL(remove_wait_queue); -/* - * Scan threshold to break wait queue walk. - * This allows a waker to take a break from holding the - * wait queue lock during the wait queue walk. - */ -#define WAITQUEUE_WALK_BREAK_CNT 64 - /* * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve @@ -78,21 +71,13 @@ EXPORT_SYMBOL(remove_wait_queue); * zero in this (rare) case, and we handle it by continuing to scan the queue. */ static int __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode, - int nr_exclusive, int wake_flags, void *key, - wait_queue_entry_t *bookmark) + int nr_exclusive, int wake_flags, void *key) { wait_queue_entry_t *curr, *next; - int cnt = 0; lockdep_assert_held(&wq_head->lock); - if (bookmark && (bookmark->flags & WQ_FLAG_BOOKMARK)) { - curr = list_next_entry(bookmark, entry); - - list_del(&bookmark->entry); - bookmark->flags = 0; - } else - curr = list_first_entry(&wq_head->head, wait_queue_entry_t, entry); + curr = list_first_entry(&wq_head->head, wait_queue_entry_t, entry); if (&curr->entry == &wq_head->head) return nr_exclusive; @@ -101,21 +86,11 @@ static int __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode, unsigned flags = curr->flags; int ret; - if (flags & WQ_FLAG_BOOKMARK) - continue; - ret = curr->func(curr, mode, wake_flags, key); if (ret < 0) break; if (ret && (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) break; - - if (bookmark && (++cnt > WAITQUEUE_WALK_BREAK_CNT) && - (&next->entry != &wq_head->head)) { - bookmark->flags = WQ_FLAG_BOOKMARK; - list_add_tail(&bookmark->entry, &next->entry); - break; - } } return nr_exclusive; @@ -125,20 +100,12 @@ static int __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int m int nr_exclusive, int wake_flags, void *key) { unsigned long flags; - wait_queue_entry_t bookmark; - int remaining = nr_exclusive; + int remaining; - bookmark.flags = 0; - bookmark.private = NULL; - bookmark.func = NULL; - INIT_LIST_HEAD(&bookmark.entry); - - do { - spin_lock_irqsave(&wq_head->lock, flags); - remaining = __wake_up_common(wq_head, mode, remaining, - wake_flags, key, &bookmark); - spin_unlock_irqrestore(&wq_head->lock, flags); - } while (bookmark.flags & WQ_FLAG_BOOKMARK); + spin_lock_irqsave(&wq_head->lock, flags); + remaining = __wake_up_common(wq_head, mode, nr_exclusive, wake_flags, + key); + spin_unlock_irqrestore(&wq_head->lock, flags); return nr_exclusive - remaining; } @@ -171,23 +138,16 @@ void __wake_up_on_current_cpu(struct wait_queue_head *wq_head, unsigned int mode */ void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr) { - __wake_up_common(wq_head, mode, nr, 0, NULL, NULL); + __wake_up_common(wq_head, mode, nr, 0, NULL); } EXPORT_SYMBOL_GPL(__wake_up_locked); void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key) { - __wake_up_common(wq_head, mode, 1, 0, key, NULL); + __wake_up_common(wq_head, mode, 1, 0, key); } EXPORT_SYMBOL_GPL(__wake_up_locked_key); -void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head, - unsigned int mode, void *key, wait_queue_entry_t *bookmark) -{ - __wake_up_common(wq_head, mode, 1, 0, key, bookmark); -} -EXPORT_SYMBOL_GPL(__wake_up_locked_key_bookmark); - /** * __wake_up_sync_key - wake up threads blocked on a waitqueue. * @wq_head: the waitqueue @@ -233,7 +193,7 @@ EXPORT_SYMBOL_GPL(__wake_up_sync_key); void __wake_up_locked_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key) { - __wake_up_common(wq_head, mode, 1, WF_SYNC, key, NULL); + __wake_up_common(wq_head, mode, 1, WF_SYNC, key); } EXPORT_SYMBOL_GPL(__wake_up_locked_sync_key); -- cgit v1.2.3 From 3657fdc2451abf135c2d20949acf57d78cc50338 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Wed, 11 Oct 2023 18:04:27 +0100 Subject: mm: move vma_policy() and anon_vma_name() decls to mm_types.h Patch series "Abstract vma_merge() and split_vma()", v4. The vma_merge() interface is very confusing and its implementation has led to numerous bugs as a result of that confusion. In addition there is duplication both in invocation of vma_merge(), but also in the common mprotect()-style pattern of attempting a merge, then if this fails, splitting the portion of a VMA about to have its attributes changed. This pattern has been copy/pasted around the kernel in each instance where such an operation has been required, each very slightly modified from the last to make it even harder to decipher what is going on. Simplify the whole thing by dividing the actual uses of vma_merge() and split_vma() into specific and abstracted functions and de-duplicate the vma_merge()/split_vma() pattern altogether. Doing so also opens the door to changing how vma_merge() is implemented - by knowing precisely what cases a caller is invoking rather than having a central interface where anything might happen we can untangle the brittle and confusing vma_merge() implementation into something more workable. For mprotect()-like cases we introduce vma_modify() which performs the vma_merge()/split_vma() pattern, returning a pointer to either the merged or split VMA or an ERR_PTR(err) if the splits fail. We provide a number of inline helper functions to make things even clearer:- * vma_modify_flags() - Prepare to modify the VMA's flags. * vma_modify_flags_name() - Prepare to modify the VMA's flags/anon_vma_name * vma_modify_policy() - Prepare to modify the VMA's mempolicy. * vma_modify_flags_uffd() - Prepare to modify the VMA's flags/uffd context. For cases where a new VMA is attempted to be merged with adjacent VMAs we add:- * vma_merge_new_vma() - Prepare to merge a new VMA. * vma_merge_extend() - Prepare to extend the end of a new VMA. This patch (of 5): The vma_policy() define is a helper specifically for a VMA field so it makes sense to host it in the memory management types header. The anon_vma_name(), anon_vma_name_alloc() and anon_vma_name_free() functions are a little out of place in mm_inline.h as they define external functions, and so it makes sense to locate them in mm_types.h. The purpose of these relocations is to make it possible to abstract static inline wrappers which invoke both of these helpers. Link: https://lkml.kernel.org/r/cover.1697043508.git.lstoakes@gmail.com Link: https://lkml.kernel.org/r/24bfc6c9e382fffbcb0ea8d424392c27d56cc8ca.1697043508.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka Cc: Alexander Viro Cc: Christian Brauner Cc: Liam R. Howlett Cc: Lorenzo Stoakes Signed-off-by: Andrew Morton --- include/linux/mempolicy.h | 4 ---- include/linux/mm_inline.h | 20 +------------------- include/linux/mm_types.h | 27 +++++++++++++++++++++++++++ 3 files changed, 28 insertions(+), 23 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index 6c2754d7bfed..1d7f4ec2614c 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -89,8 +89,6 @@ static inline struct mempolicy *mpol_dup(struct mempolicy *pol) return pol; } -#define vma_policy(vma) ((vma)->vm_policy) - static inline void mpol_get(struct mempolicy *pol) { if (pol) @@ -222,8 +220,6 @@ mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx) return NULL; } -#define vma_policy(vma) NULL - static inline int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst) { diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index 8148b30a9df1..9ae7def16cb2 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -4,6 +4,7 @@ #include #include +#include #include #include #include @@ -352,15 +353,6 @@ void lruvec_del_folio(struct lruvec *lruvec, struct folio *folio) } #ifdef CONFIG_ANON_VMA_NAME -/* - * mmap_lock should be read-locked when calling anon_vma_name(). Caller should - * either keep holding the lock while using the returned pointer or it should - * raise anon_vma_name refcount before releasing the lock. - */ -extern struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma); -extern struct anon_vma_name *anon_vma_name_alloc(const char *name); -extern void anon_vma_name_free(struct kref *kref); - /* mmap_lock should be read-locked */ static inline void anon_vma_name_get(struct anon_vma_name *anon_name) { @@ -415,16 +407,6 @@ static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1, } #else /* CONFIG_ANON_VMA_NAME */ -static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma) -{ - return NULL; -} - -static inline struct anon_vma_name *anon_vma_name_alloc(const char *name) -{ - return NULL; -} - static inline void anon_vma_name_get(struct anon_vma_name *anon_name) {} static inline void anon_vma_name_put(struct anon_vma_name *anon_name) {} static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma, diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 36c5b43999e6..21eb56145f57 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -546,6 +546,27 @@ struct anon_vma_name { char name[]; }; +#ifdef CONFIG_ANON_VMA_NAME +/* + * mmap_lock should be read-locked when calling anon_vma_name(). Caller should + * either keep holding the lock while using the returned pointer or it should + * raise anon_vma_name refcount before releasing the lock. + */ +struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma); +struct anon_vma_name *anon_vma_name_alloc(const char *name); +void anon_vma_name_free(struct kref *kref); +#else /* CONFIG_ANON_VMA_NAME */ +static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma) +{ + return NULL; +} + +static inline struct anon_vma_name *anon_vma_name_alloc(const char *name) +{ + return NULL; +} +#endif + struct vma_lock { struct rw_semaphore lock; }; @@ -662,6 +683,12 @@ struct vm_area_struct { struct vm_userfaultfd_ctx vm_userfaultfd_ctx; } __randomize_layout; +#ifdef CONFIG_NUMA +#define vma_policy(vma) ((vma)->vm_policy) +#else +#define vma_policy(vma) NULL +#endif + #ifdef CONFIG_SCHED_MM_CID struct mm_cid { u64 time; -- cgit v1.2.3 From 94d7d923395129b9248777e575c877e40007f9dc Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Wed, 11 Oct 2023 18:04:28 +0100 Subject: mm: abstract the vma_merge()/split_vma() pattern for mprotect() et al. mprotect() and other functions which change VMA parameters over a range each employ a pattern of:- 1. Attempt to merge the range with adjacent VMAs. 2. If this fails, and the range spans a subset of the VMA, split it accordingly. This is open-coded and duplicated in each case. Also in each case most of the parameters passed to vma_merge() remain the same. Create a new function, vma_modify(), which abstracts this operation, accepting only those parameters which can be changed. To avoid the mess of invoking each function call with unnecessary parameters, create inline wrapper functions for each of the modify operations, parameterised only by what is required to perform the action. We can also significantly simplify the logic - by returning the VMA if we split (or merged VMA if we do not) we no longer need specific handling for merge/split cases in any of the call sites. Note that the userfaultfd_release() case works even though it does not split VMAs - since start is set to vma->vm_start and end is set to vma->vm_end, the split logic does not trigger. In addition, since we calculate pgoff to be equal to vma->vm_pgoff + (start - vma->vm_start) >> PAGE_SHIFT, and start - vma->vm_start will be 0 in this instance, this invocation will remain unchanged. We eliminate a VM_WARN_ON() in mprotect_fixup() as this simply asserts that vma_merge() correctly ensures that flags remain the same, something that is already checked in is_mergeable_vma() and elsewhere, and in any case is not specific to mprotect(). Link: https://lkml.kernel.org/r/0dfa9368f37199a423674bf0ee312e8ea0619044.1697043508.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka Cc: Alexander Viro Cc: Christian Brauner Cc: Liam R. Howlett Signed-off-by: Andrew Morton --- fs/userfaultfd.c | 70 ++++++++++++++---------------------------------------- include/linux/mm.h | 60 ++++++++++++++++++++++++++++++++++++++++++++++ mm/madvise.c | 26 ++++---------------- mm/mempolicy.c | 26 +++----------------- mm/mlock.c | 25 ++++--------------- mm/mmap.c | 48 +++++++++++++++++++++++++++++++++++++ mm/mprotect.c | 29 ++++------------------ 7 files changed, 141 insertions(+), 143 deletions(-) (limited to 'include/linux') diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index a7c6ef764e63..ac616cfbacf5 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -927,20 +927,15 @@ static int userfaultfd_release(struct inode *inode, struct file *file) continue; } new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS; - prev = vma_merge(&vmi, mm, prev, vma->vm_start, vma->vm_end, - new_flags, vma->anon_vma, - vma->vm_file, vma->vm_pgoff, - vma_policy(vma), - NULL_VM_UFFD_CTX, anon_vma_name(vma)); - if (prev) { - vma = prev; - } else { - prev = vma; - } + vma = vma_modify_flags_uffd(&vmi, prev, vma, vma->vm_start, + vma->vm_end, new_flags, + NULL_VM_UFFD_CTX); vma_start_write(vma); userfaultfd_set_vm_flags(vma, new_flags); vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX; + + prev = vma; } mmap_write_unlock(mm); mmput(mm); @@ -1331,7 +1326,6 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, unsigned long start, end, vma_end; struct vma_iterator vmi; bool wp_async = userfaultfd_wp_async_ctx(ctx); - pgoff_t pgoff; user_uffdio_register = (struct uffdio_register __user *) arg; @@ -1484,28 +1478,14 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, vma_end = min(end, vma->vm_end); new_flags = (vma->vm_flags & ~__VM_UFFD_FLAGS) | vm_flags; - pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); - prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags, - vma->anon_vma, vma->vm_file, pgoff, - vma_policy(vma), - ((struct vm_userfaultfd_ctx){ ctx }), - anon_vma_name(vma)); - if (prev) { - /* vma_merge() invalidated the mas */ - vma = prev; - goto next; - } - if (vma->vm_start < start) { - ret = split_vma(&vmi, vma, start, 1); - if (ret) - break; - } - if (vma->vm_end > end) { - ret = split_vma(&vmi, vma, end, 0); - if (ret) - break; + vma = vma_modify_flags_uffd(&vmi, prev, vma, start, vma_end, + new_flags, + (struct vm_userfaultfd_ctx){ctx}); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + break; } - next: + /* * In the vma_merge() successful mprotect-like case 8: * the next vma was merged into the current one and @@ -1568,7 +1548,6 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, const void __user *buf = (void __user *)arg; struct vma_iterator vmi; bool wp_async = userfaultfd_wp_async_ctx(ctx); - pgoff_t pgoff; ret = -EFAULT; if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister))) @@ -1671,26 +1650,13 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, uffd_wp_range(vma, start, vma_end - start, false); new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS; - pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); - prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags, - vma->anon_vma, vma->vm_file, pgoff, - vma_policy(vma), - NULL_VM_UFFD_CTX, anon_vma_name(vma)); - if (prev) { - vma = prev; - goto next; - } - if (vma->vm_start < start) { - ret = split_vma(&vmi, vma, start, 1); - if (ret) - break; - } - if (vma->vm_end > end) { - ret = split_vma(&vmi, vma, end, 0); - if (ret) - break; + vma = vma_modify_flags_uffd(&vmi, prev, vma, start, vma_end, + new_flags, NULL_VM_UFFD_CTX); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + break; } - next: + /* * In the vma_merge() successful mprotect-like case 8: * the next vma was merged into the current one and diff --git a/include/linux/mm.h b/include/linux/mm.h index fa608cba041f..895feb814620 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3251,6 +3251,66 @@ extern struct vm_area_struct *copy_vma(struct vm_area_struct **, unsigned long addr, unsigned long len, pgoff_t pgoff, bool *need_rmap_locks); extern void exit_mmap(struct mm_struct *); +struct vm_area_struct *vma_modify(struct vma_iterator *vmi, + struct vm_area_struct *prev, + struct vm_area_struct *vma, + unsigned long start, unsigned long end, + unsigned long vm_flags, + struct mempolicy *policy, + struct vm_userfaultfd_ctx uffd_ctx, + struct anon_vma_name *anon_name); + +/* We are about to modify the VMA's flags. */ +static inline struct vm_area_struct +*vma_modify_flags(struct vma_iterator *vmi, + struct vm_area_struct *prev, + struct vm_area_struct *vma, + unsigned long start, unsigned long end, + unsigned long new_flags) +{ + return vma_modify(vmi, prev, vma, start, end, new_flags, + vma_policy(vma), vma->vm_userfaultfd_ctx, + anon_vma_name(vma)); +} + +/* We are about to modify the VMA's flags and/or anon_name. */ +static inline struct vm_area_struct +*vma_modify_flags_name(struct vma_iterator *vmi, + struct vm_area_struct *prev, + struct vm_area_struct *vma, + unsigned long start, + unsigned long end, + unsigned long new_flags, + struct anon_vma_name *new_name) +{ + return vma_modify(vmi, prev, vma, start, end, new_flags, + vma_policy(vma), vma->vm_userfaultfd_ctx, new_name); +} + +/* We are about to modify the VMA's memory policy. */ +static inline struct vm_area_struct +*vma_modify_policy(struct vma_iterator *vmi, + struct vm_area_struct *prev, + struct vm_area_struct *vma, + unsigned long start, unsigned long end, + struct mempolicy *new_pol) +{ + return vma_modify(vmi, prev, vma, start, end, vma->vm_flags, + new_pol, vma->vm_userfaultfd_ctx, anon_vma_name(vma)); +} + +/* We are about to modify the VMA's flags and/or uffd context. */ +static inline struct vm_area_struct +*vma_modify_flags_uffd(struct vma_iterator *vmi, + struct vm_area_struct *prev, + struct vm_area_struct *vma, + unsigned long start, unsigned long end, + unsigned long new_flags, + struct vm_userfaultfd_ctx new_ctx) +{ + return vma_modify(vmi, prev, vma, start, end, new_flags, + vma_policy(vma), new_ctx, anon_vma_name(vma)); +} static inline int check_data_rlimit(unsigned long rlim, unsigned long new, diff --git a/mm/madvise.c b/mm/madvise.c index 59e8860c86af..a6b48d4796ba 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -141,7 +141,6 @@ static int madvise_update_vma(struct vm_area_struct *vma, { struct mm_struct *mm = vma->vm_mm; int error; - pgoff_t pgoff; VMA_ITERATOR(vmi, mm, start); if (new_flags == vma->vm_flags && anon_vma_name_eq(anon_vma_name(vma), anon_name)) { @@ -149,30 +148,13 @@ static int madvise_update_vma(struct vm_area_struct *vma, return 0; } - pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); - *prev = vma_merge(&vmi, mm, *prev, start, end, new_flags, - vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), - vma->vm_userfaultfd_ctx, anon_name); - if (*prev) { - vma = *prev; - goto success; - } + vma = vma_modify_flags_name(&vmi, *prev, vma, start, end, new_flags, + anon_name); + if (IS_ERR(vma)) + return PTR_ERR(vma); *prev = vma; - if (start != vma->vm_start) { - error = split_vma(&vmi, vma, start, 1); - if (error) - return error; - } - - if (end != vma->vm_end) { - error = split_vma(&vmi, vma, end, 0); - if (error) - return error; - } - -success: /* vm_flags is protected by the mmap_lock held in write mode. */ vma_start_write(vma); vm_flags_reset(vma, new_flags); diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 38a47fa33ef4..8bb5b4b4b395 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -811,10 +811,7 @@ static int mbind_range(struct vma_iterator *vmi, struct vm_area_struct *vma, struct vm_area_struct **prev, unsigned long start, unsigned long end, struct mempolicy *new_pol) { - struct vm_area_struct *merged; unsigned long vmstart, vmend; - pgoff_t pgoff; - int err; vmend = min(end, vma->vm_end); if (start > vma->vm_start) { @@ -829,26 +826,9 @@ static int mbind_range(struct vma_iterator *vmi, struct vm_area_struct *vma, return 0; } - pgoff = vma->vm_pgoff + ((vmstart - vma->vm_start) >> PAGE_SHIFT); - merged = vma_merge(vmi, vma->vm_mm, *prev, vmstart, vmend, vma->vm_flags, - vma->anon_vma, vma->vm_file, pgoff, new_pol, - vma->vm_userfaultfd_ctx, anon_vma_name(vma)); - if (merged) { - *prev = merged; - return vma_replace_policy(merged, new_pol); - } - - if (vma->vm_start != vmstart) { - err = split_vma(vmi, vma, vmstart, 1); - if (err) - return err; - } - - if (vma->vm_end != vmend) { - err = split_vma(vmi, vma, vmend, 0); - if (err) - return err; - } + vma = vma_modify_policy(vmi, *prev, vma, vmstart, vmend, new_pol); + if (IS_ERR(vma)) + return PTR_ERR(vma); *prev = vma; return vma_replace_policy(vma, new_pol); diff --git a/mm/mlock.c b/mm/mlock.c index 42b6865f8f82..aa44456200e3 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -476,7 +476,6 @@ static int mlock_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma, unsigned long end, vm_flags_t newflags) { struct mm_struct *mm = vma->vm_mm; - pgoff_t pgoff; int nr_pages; int ret = 0; vm_flags_t oldflags = vma->vm_flags; @@ -487,28 +486,12 @@ static int mlock_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma, /* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */ goto out; - pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); - *prev = vma_merge(vmi, mm, *prev, start, end, newflags, - vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), - vma->vm_userfaultfd_ctx, anon_vma_name(vma)); - if (*prev) { - vma = *prev; - goto success; - } - - if (start != vma->vm_start) { - ret = split_vma(vmi, vma, start, 1); - if (ret) - goto out; - } - - if (end != vma->vm_end) { - ret = split_vma(vmi, vma, end, 0); - if (ret) - goto out; + vma = vma_modify_flags(vmi, *prev, vma, start, end, newflags); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + goto out; } -success: /* * Keep track of amount of locked VM. */ diff --git a/mm/mmap.c b/mm/mmap.c index 673429ee8a9e..bca685820763 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2437,6 +2437,54 @@ int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, return __split_vma(vmi, vma, addr, new_below); } +/* + * We are about to modify one or multiple of a VMA's flags, policy, userfaultfd + * context and anonymous VMA name within the range [start, end). + * + * As a result, we might be able to merge the newly modified VMA range with an + * adjacent VMA with identical properties. + * + * If no merge is possible and the range does not span the entirety of the VMA, + * we then need to split the VMA to accommodate the change. + * + * The function returns either the merged VMA, the original VMA if a split was + * required instead, or an error if the split failed. + */ +struct vm_area_struct *vma_modify(struct vma_iterator *vmi, + struct vm_area_struct *prev, + struct vm_area_struct *vma, + unsigned long start, unsigned long end, + unsigned long vm_flags, + struct mempolicy *policy, + struct vm_userfaultfd_ctx uffd_ctx, + struct anon_vma_name *anon_name) +{ + pgoff_t pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); + struct vm_area_struct *merged; + + merged = vma_merge(vmi, vma->vm_mm, prev, start, end, vm_flags, + vma->anon_vma, vma->vm_file, pgoff, policy, + uffd_ctx, anon_name); + if (merged) + return merged; + + if (vma->vm_start < start) { + int err = split_vma(vmi, vma, start, 1); + + if (err) + return ERR_PTR(err); + } + + if (vma->vm_end > end) { + int err = split_vma(vmi, vma, end, 0); + + if (err) + return ERR_PTR(err); + } + + return vma; +} + /* * do_vmi_align_munmap() - munmap the aligned region from @start to @end. * @vmi: The vma iterator diff --git a/mm/mprotect.c b/mm/mprotect.c index 03e2cec3e669..f1dc8f8c84ef 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -581,7 +581,6 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb, long nrpages = (end - start) >> PAGE_SHIFT; unsigned int mm_cp_flags = 0; unsigned long charged = 0; - pgoff_t pgoff; int error; if (newflags == oldflags) { @@ -631,34 +630,14 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb, newflags &= ~VM_ACCOUNT; } - /* - * First try to merge with previous and/or next vma. - */ - pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); - *pprev = vma_merge(vmi, mm, *pprev, start, end, newflags, - vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), - vma->vm_userfaultfd_ctx, anon_vma_name(vma)); - if (*pprev) { - vma = *pprev; - VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY); - goto success; + vma = vma_modify_flags(vmi, *pprev, vma, start, end, newflags); + if (IS_ERR(vma)) { + error = PTR_ERR(vma); + goto fail; } *pprev = vma; - if (start != vma->vm_start) { - error = split_vma(vmi, vma, start, 1); - if (error) - goto fail; - } - - if (end != vma->vm_end) { - error = split_vma(vmi, vma, end, 0); - if (error) - goto fail; - } - -success: /* * vm_flags and vm_page_prot are protected by the mmap_lock * held in write mode. -- cgit v1.2.3 From adb20b0c785e9e8d5e4d4a07b9c3340d7de0e5dc Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Wed, 11 Oct 2023 18:04:29 +0100 Subject: mm: make vma_merge() and split_vma() internal Now the common pattern of - attempting a merge via vma_merge() and should this fail splitting VMAs via split_vma() - has been abstracted, the former can be placed into mm/internal.h and the latter made static. In addition, the split_vma() nommu variant also need not be exported. Link: https://lkml.kernel.org/r/405f2be10e20c4e9fbcc9fe6b2dfea105f6642e0.1697043508.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka Cc: Alexander Viro Cc: Christian Brauner Cc: Liam R. Howlett Signed-off-by: Andrew Morton --- include/linux/mm.h | 9 --------- mm/internal.h | 9 +++++++++ mm/mmap.c | 8 ++++---- mm/nommu.c | 4 ++-- 4 files changed, 15 insertions(+), 15 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 895feb814620..1bddb151cd5c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3235,16 +3235,7 @@ extern int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, struct vm_area_struct *next); extern int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, unsigned long start, unsigned long end, pgoff_t pgoff); -extern struct vm_area_struct *vma_merge(struct vma_iterator *vmi, - struct mm_struct *, struct vm_area_struct *prev, unsigned long addr, - unsigned long end, unsigned long vm_flags, struct anon_vma *, - struct file *, pgoff_t, struct mempolicy *, struct vm_userfaultfd_ctx, - struct anon_vma_name *); extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *); -extern int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *, - unsigned long addr, int new_below); -extern int split_vma(struct vma_iterator *vmi, struct vm_area_struct *, - unsigned long addr, int new_below); extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *); extern void unlink_file_vma(struct vm_area_struct *); extern struct vm_area_struct *copy_vma(struct vm_area_struct **, diff --git a/mm/internal.h b/mm/internal.h index d1f7a3c612fe..2ab81c68be6c 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1002,6 +1002,15 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags); +/* + * mm/mmap.c + */ +struct vm_area_struct *vma_merge(struct vma_iterator *vmi, + struct mm_struct *, struct vm_area_struct *prev, unsigned long addr, + unsigned long end, unsigned long vm_flags, struct anon_vma *, + struct file *, pgoff_t, struct mempolicy *, struct vm_userfaultfd_ctx, + struct anon_vma_name *); + enum { /* mark page accessed */ FOLL_TOUCH = 1 << 16, diff --git a/mm/mmap.c b/mm/mmap.c index bca685820763..a516f2412f79 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2346,8 +2346,8 @@ static void unmap_region(struct mm_struct *mm, struct ma_state *mas, * has already been checked or doesn't make sense to fail. * VMA Iterator will point to the end VMA. */ -int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, - unsigned long addr, int new_below) +static int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, + unsigned long addr, int new_below) { struct vma_prepare vp; struct vm_area_struct *new; @@ -2428,8 +2428,8 @@ out_free_vma: * Split a vma into two pieces at address 'addr', a new vma is allocated * either for the first part or the tail. */ -int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, - unsigned long addr, int new_below) +static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, + unsigned long addr, int new_below) { if (vma->vm_mm->map_count >= sysctl_max_map_count) return -ENOMEM; diff --git a/mm/nommu.c b/mm/nommu.c index f9553579389b..fc4afe924ad5 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1305,8 +1305,8 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) * split a vma into two pieces at address 'addr', a new vma is allocated either * for the first part or the tail. */ -int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, - unsigned long addr, int new_below) +static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, + unsigned long addr, int new_below) { struct vm_area_struct *new; struct vm_region *region; -- cgit v1.2.3 From e8e17ee90eaf650c855adb0a3e5e965fd6692ff1 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Thu, 12 Oct 2023 18:04:28 +0100 Subject: mm: drop the assumption that VM_SHARED always implies writable Patch series "permit write-sealed memfd read-only shared mappings", v4. The man page for fcntl() describing memfd file seals states the following about F_SEAL_WRITE:- Furthermore, trying to create new shared, writable memory-mappings via mmap(2) will also fail with EPERM. With emphasis on 'writable'. In turns out in fact that currently the kernel simply disallows all new shared memory mappings for a memfd with F_SEAL_WRITE applied, rendering this documentation inaccurate. This matters because users are therefore unable to obtain a shared mapping to a memfd after write sealing altogether, which limits their usefulness. This was reported in the discussion thread [1] originating from a bug report [2]. This is a product of both using the struct address_space->i_mmap_writable atomic counter to determine whether writing may be permitted, and the kernel adjusting this counter when any VM_SHARED mapping is performed and more generally implicitly assuming VM_SHARED implies writable. It seems sensible that we should only update this mapping if VM_MAYWRITE is specified, i.e. whether it is possible that this mapping could at any point be written to. If we do so then all we need to do to permit write seals to function as documented is to clear VM_MAYWRITE when mapping read-only. It turns out this functionality already exists for F_SEAL_FUTURE_WRITE - we can therefore simply adapt this logic to do the same for F_SEAL_WRITE. We then hit a chicken and egg situation in mmap_region() where the check for VM_MAYWRITE occurs before we are able to clear this flag. To work around this, perform this check after we invoke call_mmap(), with careful consideration of error paths. Thanks to Andy Lutomirski for the suggestion! [1]:https://lore.kernel.org/all/20230324133646.16101dfa666f253c4715d965@linux-foundation.org/ [2]:https://bugzilla.kernel.org/show_bug.cgi?id=217238 This patch (of 3): There is a general assumption that VMAs with the VM_SHARED flag set are writable. If the VM_MAYWRITE flag is not set, then this is simply not the case. Update those checks which affect the struct address_space->i_mmap_writable field to explicitly test for this by introducing [vma_]is_shared_maywrite() helper functions. This remains entirely conservative, as the lack of VM_MAYWRITE guarantees that the VMA cannot be written to. Link: https://lkml.kernel.org/r/cover.1697116581.git.lstoakes@gmail.com Link: https://lkml.kernel.org/r/d978aefefa83ec42d18dfa964ad180dbcde34795.1697116581.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Suggested-by: Andy Lutomirski Reviewed-by: Jan Kara Cc: Alexander Viro Cc: Christian Brauner Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton --- include/linux/fs.h | 4 ++-- include/linux/mm.h | 11 +++++++++++ kernel/fork.c | 2 +- mm/filemap.c | 2 +- mm/madvise.c | 2 +- mm/mmap.c | 12 ++++++------ 6 files changed, 22 insertions(+), 11 deletions(-) (limited to 'include/linux') diff --git a/include/linux/fs.h b/include/linux/fs.h index fd539c9fef8e..5265186da0e2 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -454,7 +454,7 @@ extern const struct address_space_operations empty_aops; * It is also used to block modification of page cache contents through * memory mappings. * @gfp_mask: Memory allocation flags to use for allocating pages. - * @i_mmap_writable: Number of VM_SHARED mappings. + * @i_mmap_writable: Number of VM_SHARED, VM_MAYWRITE mappings. * @nr_thps: Number of THPs in the pagecache (non-shmem only). * @i_mmap: Tree of private and shared mappings. * @i_mmap_rwsem: Protects @i_mmap and @i_mmap_writable. @@ -557,7 +557,7 @@ static inline int mapping_mapped(struct address_space *mapping) /* * Might pages of this file have been modified in userspace? - * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap + * Note that i_mmap_writable counts all VM_SHARED, VM_MAYWRITE vmas: do_mmap * marks vma as VM_SHARED if it is shared, and the file was opened for * writing i.e. vma may be mprotected writable even if now readonly. * diff --git a/include/linux/mm.h b/include/linux/mm.h index 1bddb151cd5c..c3b5749ede9d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -937,6 +937,17 @@ static inline bool vma_is_accessible(struct vm_area_struct *vma) return vma->vm_flags & VM_ACCESS_FLAGS; } +static inline bool is_shared_maywrite(vm_flags_t vm_flags) +{ + return (vm_flags & (VM_SHARED | VM_MAYWRITE)) == + (VM_SHARED | VM_MAYWRITE); +} + +static inline bool vma_is_shared_maywrite(struct vm_area_struct *vma) +{ + return is_shared_maywrite(vma->vm_flags); +} + static inline struct vm_area_struct *vma_find(struct vma_iterator *vmi, unsigned long max) { diff --git a/kernel/fork.c b/kernel/fork.c index e45a4457ba83..1e6c656e0857 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -733,7 +733,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, get_file(file); i_mmap_lock_write(mapping); - if (tmp->vm_flags & VM_SHARED) + if (vma_is_shared_maywrite(tmp)) mapping_allow_writable(mapping); flush_dcache_mmap_lock(mapping); /* insert tmp into the share list, just after mpnt */ diff --git a/mm/filemap.c b/mm/filemap.c index 9ef49255f1a5..9710f43a89ac 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3618,7 +3618,7 @@ int generic_file_mmap(struct file *file, struct vm_area_struct *vma) */ int generic_file_readonly_mmap(struct file *file, struct vm_area_struct *vma) { - if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) + if (vma_is_shared_maywrite(vma)) return -EINVAL; return generic_file_mmap(file, vma); } diff --git a/mm/madvise.c b/mm/madvise.c index a6b48d4796ba..cf4d694280e9 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -970,7 +970,7 @@ static long madvise_remove(struct vm_area_struct *vma, return -EINVAL; } - if ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE)) + if (!vma_is_shared_maywrite(vma)) return -EACCES; offset = (loff_t)(start - vma->vm_start) diff --git a/mm/mmap.c b/mm/mmap.c index 3ea52451623b..0041e3631f6c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -107,7 +107,7 @@ void vma_set_page_prot(struct vm_area_struct *vma) static void __remove_shared_vm_struct(struct vm_area_struct *vma, struct file *file, struct address_space *mapping) { - if (vma->vm_flags & VM_SHARED) + if (vma_is_shared_maywrite(vma)) mapping_unmap_writable(mapping); flush_dcache_mmap_lock(mapping); @@ -384,7 +384,7 @@ static unsigned long count_vma_pages_range(struct mm_struct *mm, static void __vma_link_file(struct vm_area_struct *vma, struct address_space *mapping) { - if (vma->vm_flags & VM_SHARED) + if (vma_is_shared_maywrite(vma)) mapping_allow_writable(mapping); flush_dcache_mmap_lock(mapping); @@ -2846,7 +2846,7 @@ cannot_expand: vma->vm_pgoff = pgoff; if (file) { - if (vm_flags & VM_SHARED) { + if (is_shared_maywrite(vm_flags)) { error = mapping_map_writable(file->f_mapping); if (error) goto free_vma; @@ -2920,7 +2920,7 @@ cannot_expand: mm->map_count++; if (vma->vm_file) { i_mmap_lock_write(vma->vm_file->f_mapping); - if (vma->vm_flags & VM_SHARED) + if (vma_is_shared_maywrite(vma)) mapping_allow_writable(vma->vm_file->f_mapping); flush_dcache_mmap_lock(vma->vm_file->f_mapping); @@ -2937,7 +2937,7 @@ cannot_expand: /* Once vma denies write, undo our temporary denial count */ unmap_writable: - if (file && vm_flags & VM_SHARED) + if (file && is_shared_maywrite(vm_flags)) mapping_unmap_writable(file->f_mapping); file = vma->vm_file; ksm_add_vma(vma); @@ -2985,7 +2985,7 @@ unmap_and_free_vma: unmap_region(mm, &vmi.mas, vma, prev, next, vma->vm_start, vma->vm_end, vma->vm_end, true); } - if (file && (vm_flags & VM_SHARED)) + if (file && is_shared_maywrite(vm_flags)) mapping_unmap_writable(file->f_mapping); free_vma: vm_area_free(vma); -- cgit v1.2.3 From 28464bbb2ddc199433383994bcb9600c8034afa1 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Thu, 12 Oct 2023 18:04:29 +0100 Subject: mm: update memfd seal write check to include F_SEAL_WRITE The seal_check_future_write() function is called by shmem_mmap() or hugetlbfs_file_mmap() to disallow any future writable mappings of an memfd sealed this way. The F_SEAL_WRITE flag is not checked here, as that is handled via the mapping->i_mmap_writable mechanism and so any attempt at a mapping would fail before this could be run. However we intend to change this, meaning this check can be performed for F_SEAL_WRITE mappings also. The logic here is equally applicable to both flags, so update this function to accommodate both and rename it accordingly. Link: https://lkml.kernel.org/r/913628168ce6cce77df7d13a63970bae06a526e0.1697116581.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Jan Kara Cc: Alexander Viro Cc: Andy Lutomirski Cc: Christian Brauner Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton --- fs/hugetlbfs/inode.c | 2 +- include/linux/mm.h | 15 ++++++++------- mm/shmem.c | 2 +- 3 files changed, 10 insertions(+), 9 deletions(-) (limited to 'include/linux') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 926d01c493fb..85cd418d2340 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -135,7 +135,7 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND); vma->vm_ops = &hugetlb_vm_ops; - ret = seal_check_future_write(info->seals, vma); + ret = seal_check_write(info->seals, vma); if (ret) return ret; diff --git a/include/linux/mm.h b/include/linux/mm.h index c3b5749ede9d..86e040e886e4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4076,25 +4076,26 @@ static inline void mem_dump_obj(void *object) {} #endif /** - * seal_check_future_write - Check for F_SEAL_FUTURE_WRITE flag and handle it + * seal_check_write - Check for F_SEAL_WRITE or F_SEAL_FUTURE_WRITE flags and + * handle them. * @seals: the seals to check * @vma: the vma to operate on * - * Check whether F_SEAL_FUTURE_WRITE is set; if so, do proper check/handling on - * the vma flags. Return 0 if check pass, or <0 for errors. + * Check whether F_SEAL_WRITE or F_SEAL_FUTURE_WRITE are set; if so, do proper + * check/handling on the vma flags. Return 0 if check pass, or <0 for errors. */ -static inline int seal_check_future_write(int seals, struct vm_area_struct *vma) +static inline int seal_check_write(int seals, struct vm_area_struct *vma) { - if (seals & F_SEAL_FUTURE_WRITE) { + if (seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) { /* * New PROT_WRITE and MAP_SHARED mmaps are not allowed when - * "future write" seal active. + * write seals are active. */ if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE)) return -EPERM; /* - * Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as + * Since an F_SEAL_[FUTURE_]WRITE sealed memfd can be mapped as * MAP_SHARED and read-only, take care to not allow mprotect to * revert protections on such mappings. Do this only for shared * mappings. For private mappings, don't need to mask diff --git a/mm/shmem.c b/mm/shmem.c index 61b170324e5c..bcbe9dbb9f5f 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2378,7 +2378,7 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma) struct shmem_inode_info *info = SHMEM_I(inode); int ret; - ret = seal_check_future_write(info->seals, vma); + ret = seal_check_write(info->seals, vma); if (ret) return ret; -- cgit v1.2.3 From 3decb8564eff88a2533f83b01cec2cf9259c3eaf Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 16 Oct 2023 21:10:49 +0100 Subject: buffer: make folio_create_empty_buffers() return a buffer_head Patch series "Finish the create_empty_buffers() transition", v2. Pankaj recently added folio_create_empty_buffers() as the folio equivalent to create_empty_buffers(). This patch set finishes the conversion by first converting all remaining filesystems to call folio_create_empty_buffers(), then renaming it back to create_empty_buffers(). I took the opportunity to make a few simplifications like making folio_create_empty_buffers() return the head buffer and extracting get_nth_bh() from nilfs2. A few of the patches in this series aren't directly related to create_empty_buffers(), but I saw them while I was working on this and thought they'd be easy enough to add to this series. Compile-tested only, other than ext4. This patch (of 26): Almost all callers want to know the first BH that was allocated for this folio. We already have that handy, so return it. Link: https://lkml.kernel.org/r/20231016201114.1928083-1-willy@infradead.org Link: https://lkml.kernel.org/r/20231016201114.1928083-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Pankaj Raghav Cc: Andreas Gruenbacher Cc: Ryusuke Konishi Signed-off-by: Andrew Morton --- fs/buffer.c | 24 +++++++++++++----------- include/linux/buffer_head.h | 4 ++-- 2 files changed, 15 insertions(+), 13 deletions(-) (limited to 'include/linux') diff --git a/fs/buffer.c b/fs/buffer.c index 86ddfa52c699..bfa7604d1891 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1641,8 +1641,8 @@ EXPORT_SYMBOL(block_invalidate_folio); * block_dirty_folio() via private_lock. try_to_free_buffers * is already excluded via the folio lock. */ -void folio_create_empty_buffers(struct folio *folio, unsigned long blocksize, - unsigned long b_state) +struct buffer_head *folio_create_empty_buffers(struct folio *folio, + unsigned long blocksize, unsigned long b_state) { struct buffer_head *bh, *head, *tail; gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT | __GFP_NOFAIL; @@ -1669,6 +1669,8 @@ void folio_create_empty_buffers(struct folio *folio, unsigned long blocksize, } folio_attach_private(folio, head); spin_unlock(&folio->mapping->private_lock); + + return head; } EXPORT_SYMBOL(folio_create_empty_buffers); @@ -1770,13 +1772,15 @@ static struct buffer_head *folio_create_buffers(struct folio *folio, struct inode *inode, unsigned int b_state) { + struct buffer_head *bh; + BUG_ON(!folio_test_locked(folio)); - if (!folio_buffers(folio)) - folio_create_empty_buffers(folio, - 1 << READ_ONCE(inode->i_blkbits), - b_state); - return folio_buffers(folio); + bh = folio_buffers(folio); + if (!bh) + bh = folio_create_empty_buffers(folio, + 1 << READ_ONCE(inode->i_blkbits), b_state); + return bh; } /* @@ -2676,10 +2680,8 @@ int block_truncate_page(struct address_space *mapping, return PTR_ERR(folio); bh = folio_buffers(folio); - if (!bh) { - folio_create_empty_buffers(folio, blocksize, 0); - bh = folio_buffers(folio); - } + if (!bh) + bh = folio_create_empty_buffers(folio, blocksize, 0); /* Find the buffer that contains "offset" */ offset = offset_in_folio(folio, from); diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 3dc4720e4773..1001244a8941 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -203,8 +203,8 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, bool retry); void create_empty_buffers(struct page *, unsigned long, unsigned long b_state); -void folio_create_empty_buffers(struct folio *folio, unsigned long blocksize, - unsigned long b_state); +struct buffer_head *folio_create_empty_buffers(struct folio *folio, + unsigned long blocksize, unsigned long b_state); void end_buffer_read_sync(struct buffer_head *bh, int uptodate); void end_buffer_write_sync(struct buffer_head *bh, int uptodate); void end_buffer_async_write(struct buffer_head *bh, int uptodate); -- cgit v1.2.3 From 0217fbb0271a7c78e16629cf45375916ec2eb35f Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 16 Oct 2023 21:10:52 +0100 Subject: buffer: add get_nth_bh() Extract this useful helper from nilfs_page_get_nth_block() Link: https://lkml.kernel.org/r/20231016201114.1928083-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Ryusuke Konishi Cc: Andreas Gruenbacher Cc: Pankaj Raghav Signed-off-by: Andrew Morton --- fs/nilfs2/page.h | 7 +------ include/linux/buffer_head.h | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h index 21ddcdd4d63e..344d71942d36 100644 --- a/fs/nilfs2/page.h +++ b/fs/nilfs2/page.h @@ -55,12 +55,7 @@ unsigned long nilfs_find_uncommitted_extent(struct inode *inode, static inline struct buffer_head * nilfs_page_get_nth_block(struct page *page, unsigned int count) { - struct buffer_head *bh = page_buffers(page); - - while (count-- > 0) - bh = bh->b_this_page; - get_bh(bh); - return bh; + return get_nth_bh(page_buffers(page), count); } #endif /* _NILFS_PAGE_H */ diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 1001244a8941..3d85a0cf0ca5 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -457,6 +457,28 @@ __bread(struct block_device *bdev, sector_t block, unsigned size) return __bread_gfp(bdev, block, size, __GFP_MOVABLE); } +/** + * get_nth_bh - Get a reference on the n'th buffer after this one. + * @bh: The buffer to start counting from. + * @count: How many buffers to skip. + * + * This is primarily useful for finding the nth buffer in a folio; in + * that case you pass the head buffer and the byte offset in the folio + * divided by the block size. It can be used for other purposes, but + * it will wrap at the end of the folio rather than returning NULL or + * proceeding to the next folio for you. + * + * Return: The requested buffer with an elevated refcount. + */ +static inline __must_check +struct buffer_head *get_nth_bh(struct buffer_head *bh, unsigned int count) +{ + while (count--) + bh = bh->b_this_page; + get_bh(bh); + return bh; +} + bool block_dirty_folio(struct address_space *mapping, struct folio *folio); #ifdef CONFIG_BUFFER_HEAD -- cgit v1.2.3 From 0a88810d9b76e6ecfd234f5728e27344a39e3ff8 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 16 Oct 2023 21:11:14 +0100 Subject: buffer: remove folio_create_empty_buffers() With all users converted, remove the old create_empty_buffers() and rename folio_create_empty_buffers() to create_empty_buffers(). Link: https://lkml.kernel.org/r/20231016201114.1928083-28-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Andreas Gruenbacher Cc: Pankaj Raghav Cc: Ryusuke Konishi Signed-off-by: Andrew Morton --- fs/buffer.c | 13 +++---------- fs/ext4/inode.c | 6 +++--- fs/ext4/move_extent.c | 4 ++-- fs/gfs2/aops.c | 2 +- fs/gfs2/bmap.c | 2 +- fs/gfs2/meta_io.c | 2 +- fs/gfs2/quota.c | 2 +- fs/mpage.c | 2 +- fs/nilfs2/mdt.c | 2 +- fs/nilfs2/page.c | 4 ++-- fs/nilfs2/segment.c | 2 +- fs/ntfs/aops.c | 4 ++-- fs/ntfs/file.c | 2 +- fs/ntfs3/file.c | 2 +- fs/ocfs2/aops.c | 2 +- fs/reiserfs/inode.c | 2 +- fs/ufs/util.c | 2 +- include/linux/buffer_head.h | 4 +--- 18 files changed, 25 insertions(+), 34 deletions(-) (limited to 'include/linux') diff --git a/fs/buffer.c b/fs/buffer.c index bfa7604d1891..657a62bab73d 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1641,7 +1641,7 @@ EXPORT_SYMBOL(block_invalidate_folio); * block_dirty_folio() via private_lock. try_to_free_buffers * is already excluded via the folio lock. */ -struct buffer_head *folio_create_empty_buffers(struct folio *folio, +struct buffer_head *create_empty_buffers(struct folio *folio, unsigned long blocksize, unsigned long b_state) { struct buffer_head *bh, *head, *tail; @@ -1672,13 +1672,6 @@ struct buffer_head *folio_create_empty_buffers(struct folio *folio, return head; } -EXPORT_SYMBOL(folio_create_empty_buffers); - -void create_empty_buffers(struct page *page, - unsigned long blocksize, unsigned long b_state) -{ - folio_create_empty_buffers(page_folio(page), blocksize, b_state); -} EXPORT_SYMBOL(create_empty_buffers); /** @@ -1778,7 +1771,7 @@ static struct buffer_head *folio_create_buffers(struct folio *folio, bh = folio_buffers(folio); if (!bh) - bh = folio_create_empty_buffers(folio, + bh = create_empty_buffers(folio, 1 << READ_ONCE(inode->i_blkbits), b_state); return bh; } @@ -2681,7 +2674,7 @@ int block_truncate_page(struct address_space *mapping, bh = folio_buffers(folio); if (!bh) - bh = folio_create_empty_buffers(folio, blocksize, 0); + bh = create_empty_buffers(folio, blocksize, 0); /* Find the buffer that contains "offset" */ offset = offset_in_folio(folio, from); diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 8e431ff2fd95..347fc8986e93 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1021,7 +1021,7 @@ static int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len, head = folio_buffers(folio); if (!head) - head = folio_create_empty_buffers(folio, blocksize, 0); + head = create_empty_buffers(folio, blocksize, 0); bbits = ilog2(blocksize); block = (sector_t)folio->index << (PAGE_SHIFT - bbits); @@ -1151,7 +1151,7 @@ retry_grab: * starting the handle. */ if (!folio_buffers(folio)) - folio_create_empty_buffers(folio, inode->i_sb->s_blocksize, 0); + create_empty_buffers(folio, inode->i_sb->s_blocksize, 0); folio_unlock(folio); @@ -3642,7 +3642,7 @@ static int __ext4_block_zero_page_range(handle_t *handle, bh = folio_buffers(folio); if (!bh) - bh = folio_create_empty_buffers(folio, blocksize, 0); + bh = create_empty_buffers(folio, blocksize, 0); /* Find the buffer that contains "offset" */ pos = blocksize; diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index 7fe448fb948b..3aa57376d9c2 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -184,7 +184,7 @@ mext_page_mkuptodate(struct folio *folio, unsigned from, unsigned to) blocksize = i_blocksize(inode); head = folio_buffers(folio); if (!head) - head = folio_create_empty_buffers(folio, blocksize, 0); + head = create_empty_buffers(folio, blocksize, 0); block = (sector_t)folio->index << (PAGE_SHIFT - inode->i_blkbits); for (bh = head, block_start = 0; bh != head || !block_start; @@ -380,7 +380,7 @@ data_copy: * but keeping in mind that i_size will not change */ bh = folio_buffers(folio[0]); if (!bh) - bh = folio_create_empty_buffers(folio[0], + bh = create_empty_buffers(folio[0], 1 << orig_inode->i_blkbits, 0); for (i = 0; i < data_offset_in_page; i++) bh = bh->b_this_page; diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c index c26d48355cc2..6b060fc9e260 100644 --- a/fs/gfs2/aops.c +++ b/fs/gfs2/aops.c @@ -130,7 +130,7 @@ static int __gfs2_jdata_write_folio(struct folio *folio, if (folio_test_checked(folio)) { folio_clear_checked(folio); if (!folio_buffers(folio)) { - folio_create_empty_buffers(folio, + create_empty_buffers(folio, inode->i_sb->s_blocksize, BIT(BH_Dirty)|BIT(BH_Uptodate)); } diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index 247d2c16593c..f1eee3f4704b 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -71,7 +71,7 @@ static int gfs2_unstuffer_folio(struct gfs2_inode *ip, struct buffer_head *dibh, struct buffer_head *bh = folio_buffers(folio); if (!bh) - bh = folio_create_empty_buffers(folio, + bh = create_empty_buffers(folio, BIT(inode->i_blkbits), BIT(BH_Uptodate)); if (!buffer_mapped(bh)) diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c index f6d40d51f5ed..25ceb0805df2 100644 --- a/fs/gfs2/meta_io.c +++ b/fs/gfs2/meta_io.c @@ -134,7 +134,7 @@ struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create) mapping_gfp_mask(mapping) | __GFP_NOFAIL); bh = folio_buffers(folio); if (!bh) - bh = folio_create_empty_buffers(folio, + bh = create_empty_buffers(folio, sdp->sd_sb.sb_bsize, 0); } else { folio = __filemap_get_folio(mapping, index, diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c index 25354278cecb..2f1328af34f4 100644 --- a/fs/gfs2/quota.c +++ b/fs/gfs2/quota.c @@ -763,7 +763,7 @@ static int gfs2_write_buf_to_page(struct gfs2_sbd *sdp, unsigned long index, return PTR_ERR(folio); bh = folio_buffers(folio); if (!bh) - bh = folio_create_empty_buffers(folio, bsize, 0); + bh = create_empty_buffers(folio, bsize, 0); for (;;) { /* Find the beginning block within the folio */ diff --git a/fs/mpage.c b/fs/mpage.c index 964a6efe594d..ffb064ed9d04 100644 --- a/fs/mpage.c +++ b/fs/mpage.c @@ -119,7 +119,7 @@ static void map_buffer_to_folio(struct folio *folio, struct buffer_head *bh, folio_mark_uptodate(folio); return; } - head = folio_create_empty_buffers(folio, i_blocksize(inode), 0); + head = create_empty_buffers(folio, i_blocksize(inode), 0); } page_bh = head; diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c index 7b754e6494d7..c97c77a39668 100644 --- a/fs/nilfs2/mdt.c +++ b/fs/nilfs2/mdt.c @@ -568,7 +568,7 @@ int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh) bh_frozen = folio_buffers(folio); if (!bh_frozen) - bh_frozen = folio_create_empty_buffers(folio, 1 << blkbits, 0); + bh_frozen = create_empty_buffers(folio, 1 << blkbits, 0); bh_frozen = get_nth_bh(bh_frozen, bh_offset(bh) >> blkbits); diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c index 696215d899bf..06b04758f289 100644 --- a/fs/nilfs2/page.c +++ b/fs/nilfs2/page.c @@ -34,7 +34,7 @@ static struct buffer_head *__nilfs_get_folio_block(struct folio *folio, struct buffer_head *bh = folio_buffers(folio); if (!bh) - bh = folio_create_empty_buffers(folio, 1 << blkbits, b_state); + bh = create_empty_buffers(folio, 1 << blkbits, b_state); first_block = (unsigned long)index << (PAGE_SHIFT - blkbits); bh = get_nth_bh(bh, block - first_block); @@ -204,7 +204,7 @@ static void nilfs_copy_folio(struct folio *dst, struct folio *src, sbh = folio_buffers(src); dbh = folio_buffers(dst); if (!dbh) - dbh = folio_create_empty_buffers(dst, sbh->b_size, 0); + dbh = create_empty_buffers(dst, sbh->b_size, 0); if (copy_dirty) mask |= BIT(BH_Dirty); diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c index 94388fe83cf8..55e31cc903d1 100644 --- a/fs/nilfs2/segment.c +++ b/fs/nilfs2/segment.c @@ -732,7 +732,7 @@ static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode, } head = folio_buffers(folio); if (!head) - head = folio_create_empty_buffers(folio, + head = create_empty_buffers(folio, i_blocksize(inode), 0); folio_unlock(folio); diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c index c4426992a2ee..71e31e789b29 100644 --- a/fs/ntfs/aops.c +++ b/fs/ntfs/aops.c @@ -189,7 +189,7 @@ static int ntfs_read_block(struct folio *folio) head = folio_buffers(folio); if (!head) - head = folio_create_empty_buffers(folio, blocksize, 0); + head = create_empty_buffers(folio, blocksize, 0); bh = head; /* @@ -555,7 +555,7 @@ static int ntfs_write_block(struct folio *folio, struct writeback_control *wbc) head = folio_buffers(folio); if (!head) { BUG_ON(!folio_test_uptodate(folio)); - head = folio_create_empty_buffers(folio, blocksize, + head = create_empty_buffers(folio, blocksize, (1 << BH_Uptodate) | (1 << BH_Dirty)); } bh = head; diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c index 099141d20db6..297c0b9db621 100644 --- a/fs/ntfs/file.c +++ b/fs/ntfs/file.c @@ -625,7 +625,7 @@ do_next_folio: * create_empty_buffers() will create uptodate/dirty * buffers if the folio is uptodate/dirty. */ - head = folio_create_empty_buffers(folio, blocksize, 0); + head = create_empty_buffers(folio, blocksize, 0); bh = head; do { VCN cdelta; diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c index a003a69091a2..66fd4ac28395 100644 --- a/fs/ntfs3/file.c +++ b/fs/ntfs3/file.c @@ -203,7 +203,7 @@ static int ntfs_zero_range(struct inode *inode, u64 vbo, u64 vbo_to) head = folio_buffers(folio); if (!head) - head = folio_create_empty_buffers(folio, blocksize, 0); + head = create_empty_buffers(folio, blocksize, 0); bh = head; bh_off = 0; diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 95d1e70b4401..a6405dd5df09 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -601,7 +601,7 @@ int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno, head = folio_buffers(folio); if (!head) - head = folio_create_empty_buffers(folio, bsize, 0); + head = create_empty_buffers(folio, bsize, 0); for (bh = head, block_start = 0; bh != head || !block_start; bh = bh->b_this_page, block_start += bsize) { diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c index d9737235b8e0..a9075c4843ed 100644 --- a/fs/reiserfs/inode.c +++ b/fs/reiserfs/inode.c @@ -2539,7 +2539,7 @@ static int reiserfs_write_full_folio(struct folio *folio, */ head = folio_buffers(folio); if (!head) - head = folio_create_empty_buffers(folio, s->s_blocksize, + head = create_empty_buffers(folio, s->s_blocksize, (1 << BH_Dirty) | (1 << BH_Uptodate)); /* diff --git a/fs/ufs/util.c b/fs/ufs/util.c index d32de30009a0..13ba34e6d64f 100644 --- a/fs/ufs/util.c +++ b/fs/ufs/util.c @@ -264,6 +264,6 @@ struct folio *ufs_get_locked_folio(struct address_space *mapping, } } if (!folio_buffers(folio)) - folio_create_empty_buffers(folio, 1 << inode->i_blkbits, 0); + create_empty_buffers(folio, 1 << inode->i_blkbits, 0); return folio; } diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 3d85a0cf0ca5..5f23ee599889 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -201,9 +201,7 @@ struct buffer_head *folio_alloc_buffers(struct folio *folio, unsigned long size, gfp_t gfp); struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, bool retry); -void create_empty_buffers(struct page *, unsigned long, - unsigned long b_state); -struct buffer_head *folio_create_empty_buffers(struct folio *folio, +struct buffer_head *create_empty_buffers(struct folio *folio, unsigned long blocksize, unsigned long b_state); void end_buffer_read_sync(struct buffer_head *bh, int uptodate); void end_buffer_write_sync(struct buffer_head *bh, int uptodate); -- cgit v1.2.3 From ca71fe1ad9221a89c6a25f49159c600d9e598ae1 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 16 Oct 2023 13:29:54 +0800 Subject: mm, pcp: avoid to drain PCP when process exit Patch series "mm: PCP high auto-tuning", v3. The page allocation performance requirements of different workloads are often different. So, we need to tune the PCP (Per-CPU Pageset) high on each CPU automatically to optimize the page allocation performance. The list of patches in series is as follows, [1/9] mm, pcp: avoid to drain PCP when process exit [2/9] cacheinfo: calculate per-CPU data cache size [3/9] mm, pcp: reduce lock contention for draining high-order pages [4/9] mm: restrict the pcp batch scale factor to avoid too long latency [5/9] mm, page_alloc: scale the number of pages that are batch allocated [6/9] mm: add framework for PCP high auto-tuning [7/9] mm: tune PCP high automatically [8/9] mm, pcp: decrease PCP high if free pages < high watermark [9/9] mm, pcp: reduce detecting time of consecutive high order page freeing Patch [1/9], [2/9], [3/9] optimize the PCP draining for consecutive high-order pages freeing. Patch [4/9], [5/9] optimize batch freeing and allocating. Patch [6/9], [7/9], [8/9] implement and optimize a PCP high auto-tuning method. Patch [9/9] optimize the PCP draining for consecutive high order page freeing based on PCP high auto-tuning. The test results for patches with performance impact are as follows, kbuild ====== On a 2-socket Intel server with 224 logical CPU, we run 8 kbuild instances in parallel (each with `make -j 28`) in 8 cgroup. This simulates the kbuild server that is used by 0-Day kbuild service. build time lock contend% free_high alloc_zone ---------- ---------- --------- ---------- base 100.0 14.0 100.0 100.0 patch1 99.5 12.8 19.5 95.6 patch3 99.4 12.6 7.1 95.6 patch5 98.6 11.0 8.1 97.1 patch7 95.1 0.5 2.8 15.6 patch9 95.0 1.0 8.8 20.0 The PCP draining optimization (patch [1/9], [3/9]) and PCP batch allocation optimization (patch [5/9]) reduces zone lock contention a little. The PCP high auto-tuning (patch [7/9], [9/9]) reduces build time visibly. Where the tuning target: the number of pages allocated from zone reduces greatly. So, the zone contention cycles% reduces greatly. With PCP tuning patches (patch [7/9], [9/9]), the average used memory during test increases up to 18.4% because more pages are cached in PCP. But at the end of the test, the number of the used memory decreases to the same level as that of the base patch. That is, the pages cached in PCP will be released to zone after not being used actively. netperf SCTP_STREAM_MANY ======================== On a 2-socket Intel server with 128 logical CPU, we tested SCTP_STREAM_MANY test case of netperf test suite with 64-pair processes. score lock contend% free_high alloc_zone cache miss rate% ----- ---------- --------- ---------- ---------------- base 100.0 2.1 100.0 100.0 1.3 patch1 99.4 2.1 99.4 99.4 1.3 patch3 106.4 1.3 13.3 106.3 1.3 patch5 106.0 1.2 13.2 105.9 1.3 patch7 103.4 1.9 6.7 90.3 7.6 patch9 108.6 1.3 13.7 108.6 1.3 The PCP draining optimization (patch [1/9]+[3/9]) improves performance. The PCP high auto-tuning (patch [7/9]) reduces performance a little because PCP draining cannot be triggered in time sometimes. So, the cache miss rate% increases. The further PCP draining optimization (patch [9/9]) based on PCP tuning restore the performance. lmbench3 UNIX (AF_UNIX) ======================= On a 2-socket Intel server with 128 logical CPU, we tested UNIX (AF_UNIX socket) test case of lmbench3 test suite with 16-pair processes. score lock contend% free_high alloc_zone cache miss rate% ----- ---------- --------- ---------- ---------------- base 100.0 51.4 100.0 100.0 0.2 patch1 116.8 46.1 69.5 104.3 0.2 patch3 199.1 21.3 7.0 104.9 0.2 patch5 200.0 20.8 7.1 106.9 0.3 patch7 191.6 19.9 6.8 103.8 2.8 patch9 193.4 21.7 7.0 104.7 2.1 The PCP draining optimization (patch [1/9], [3/9]) improves performance much. The PCP tuning (patch [7/9]) reduces performance a little because PCP draining cannot be triggered in time sometimes. The further PCP draining optimization (patch [9/9]) based on PCP tuning restores the performance partly. The patchset adds several fields in struct per_cpu_pages. The struct layout before/after the patchset is as follows, base ==== struct per_cpu_pages { spinlock_t lock; /* 0 4 */ int count; /* 4 4 */ int high; /* 8 4 */ int batch; /* 12 4 */ short int free_factor; /* 16 2 */ short int expire; /* 18 2 */ /* XXX 4 bytes hole, try to pack */ struct list_head lists[13]; /* 24 208 */ /* size: 256, cachelines: 4, members: 7 */ /* sum members: 228, holes: 1, sum holes: 4 */ /* padding: 24 */ } __attribute__((__aligned__(64))); patched ======= struct per_cpu_pages { spinlock_t lock; /* 0 4 */ int count; /* 4 4 */ int high; /* 8 4 */ int high_min; /* 12 4 */ int high_max; /* 16 4 */ int batch; /* 20 4 */ u8 flags; /* 24 1 */ u8 alloc_factor; /* 25 1 */ u8 expire; /* 26 1 */ /* XXX 1 byte hole, try to pack */ short int free_count; /* 28 2 */ /* XXX 2 bytes hole, try to pack */ struct list_head lists[13]; /* 32 208 */ /* size: 256, cachelines: 4, members: 11 */ /* sum members: 237, holes: 2, sum holes: 3 */ /* padding: 16 */ } __attribute__((__aligned__(64))); The size of the struct doesn't changed with the patchset. This patch (of 9): In commit f26b3fa04611 ("mm/page_alloc: limit number of high-order pages on PCP during bulk free"), the PCP (Per-CPU Pageset) will be drained when PCP is mostly used for high-order pages freeing to improve the cache-hot pages reusing between page allocation and freeing CPUs. But, the PCP draining mechanism may be triggered unexpectedly when process exits. With some customized trace point, it was found that PCP draining (free_high == true) was triggered with the order-1 page freeing with the following call stack, => free_unref_page_commit => free_unref_page => __mmdrop => exit_mm => do_exit => do_group_exit => __x64_sys_exit_group => do_syscall_64 Checking the source code, this is the page table PGD freeing (mm_free_pgd()). It's a order-1 page freeing if CONFIG_PAGE_TABLE_ISOLATION=y. Which is a common configuration for security. Just before that, page freeing with the following call stack was found, => free_unref_page_commit => free_unref_page_list => release_pages => tlb_batch_pages_flush => tlb_finish_mmu => exit_mmap => __mmput => exit_mm => do_exit => do_group_exit => __x64_sys_exit_group => do_syscall_64 So, when a process exits, - a large number of user pages of the process will be freed without page allocation, it's highly possible that pcp->free_factor becomes > 0. In fact, this is expected behavior to improve process exit performance. - after freeing all user pages, the PGD will be freed, which is a order-1 page freeing, PCP will be drained. All in all, when a process exits, it's high possible that the PCP will be drained. This is an unexpected behavior. To avoid this, in the patch, the PCP draining will only be triggered for 2 consecutive high-order page freeing. On a 2-socket Intel server with 224 logical CPU, we run 8 kbuild instances in parallel (each with `make -j 28`) in 8 cgroup. This simulates the kbuild server that is used by 0-Day kbuild service. With the patch, the cycles% of the spinlock contention (mostly for zone lock) decreases from 14.0% to 12.8% (with PCP size == 367). The number of PCP draining for high order pages freeing (free_high) decreases 80.5%. This helps network workload too for reduced zone lock contention. On a 2-socket Intel server with 128 logical CPU, with the patch, the network bandwidth of the UNIX (AF_UNIX) test case of lmbench test suite with 16-pair processes increase 16.8%. The cycles% of the spinlock contention (mostly for zone lock) decreases from 51.4% to 46.1%. The number of PCP draining for high order pages freeing (free_high) decreases 30.5%. The cache miss rate keeps 0.2%. Link: https://lkml.kernel.org/r/20231016053002.756205-1-ying.huang@intel.com Link: https://lkml.kernel.org/r/20231016053002.756205-2-ying.huang@intel.com Signed-off-by: "Huang, Ying" Acked-by: Mel Gorman Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Johannes Weiner Cc: Dave Hansen Cc: Michal Hocko Cc: Pavel Tatashin Cc: Matthew Wilcox Cc: Christoph Lameter Cc: Arjan van de Ven Cc: Sudeep Holla Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 12 +++++++++++- mm/page_alloc.c | 11 ++++++++--- 2 files changed, 19 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 486587fcd27f..de313f1c15f9 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -674,12 +674,22 @@ enum zone_watermarks { #define high_wmark_pages(z) (z->_watermark[WMARK_HIGH] + z->watermark_boost) #define wmark_pages(z, i) (z->_watermark[i] + z->watermark_boost) +/* + * Flags used in pcp->flags field. + * + * PCPF_PREV_FREE_HIGH_ORDER: a high-order page is freed in the + * previous page freeing. To avoid to drain PCP for an accident + * high-order page freeing. + */ +#define PCPF_PREV_FREE_HIGH_ORDER BIT(0) + struct per_cpu_pages { spinlock_t lock; /* Protects lists field */ int count; /* number of pages in the list */ int high; /* high watermark, emptying needed */ int batch; /* chunk size for buddy add/remove */ - short free_factor; /* batch scaling factor during free */ + u8 flags; /* protected by pcp->lock */ + u8 free_factor; /* batch scaling factor during free */ #ifdef CONFIG_NUMA short expire; /* When 0, remote pagesets are drained */ #endif diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f46e519618a0..de547ef9a9ad 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2370,7 +2370,7 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, { int high; int pindex; - bool free_high; + bool free_high = false; __count_vm_events(PGFREE, 1 << order); pindex = order_to_pindex(migratetype, order); @@ -2383,8 +2383,13 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, * freeing without allocation. The remainder after bulk freeing * stops will be drained from vmstat refresh context. */ - free_high = (pcp->free_factor && order && order <= PAGE_ALLOC_COSTLY_ORDER); - + if (order && order <= PAGE_ALLOC_COSTLY_ORDER) { + free_high = (pcp->free_factor && + (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER)); + pcp->flags |= PCPF_PREV_FREE_HIGH_ORDER; + } else if (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) { + pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER; + } high = nr_pcp_high(pcp, zone, free_high); if (pcp->count >= high) { free_pcppages_bulk(zone, nr_pcp_free(pcp, high, free_high), pcp, pindex); -- cgit v1.2.3 From 94a3bfe4073cd88b05f7fb201ea7bf9dfa2cf5d5 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 16 Oct 2023 13:29:55 +0800 Subject: cacheinfo: calculate size of per-CPU data cache slice This can be used to estimate the size of the data cache slice that can be used by one CPU under ideal circumstances. Both DATA caches and UNIFIED caches are used in calculation. So, the users need to consider the impact of the code cache usage. Because the cache inclusive/non-inclusive information isn't available now, we just use the size of the per-CPU slice of LLC to make the result more predictable across architectures. This may be improved when more cache information is available in the future. A brute-force algorithm to iterate all online CPUs is used to avoid to allocate an extra cpumask, especially in offline callback. Link: https://lkml.kernel.org/r/20231016053002.756205-3-ying.huang@intel.com Signed-off-by: "Huang, Ying" Acked-by: Mel Gorman Cc: Sudeep Holla Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Johannes Weiner Cc: Dave Hansen Cc: Michal Hocko Cc: Pavel Tatashin Cc: Matthew Wilcox Cc: Christoph Lameter Cc: Arjan van de Ven Signed-off-by: Andrew Morton --- drivers/base/cacheinfo.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++- include/linux/cacheinfo.h | 1 + 2 files changed, 49 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index cbae8be1fe52..585c66fce9d9 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -898,6 +898,48 @@ err: return rc; } +/* + * Calculate the size of the per-CPU data cache slice. This can be + * used to estimate the size of the data cache slice that can be used + * by one CPU under ideal circumstances. UNIFIED caches are counted + * in addition to DATA caches. So, please consider code cache usage + * when use the result. + * + * Because the cache inclusive/non-inclusive information isn't + * available, we just use the size of the per-CPU slice of LLC to make + * the result more predictable across architectures. + */ +static void update_per_cpu_data_slice_size_cpu(unsigned int cpu) +{ + struct cpu_cacheinfo *ci; + struct cacheinfo *llc; + unsigned int nr_shared; + + if (!last_level_cache_is_valid(cpu)) + return; + + ci = ci_cacheinfo(cpu); + llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1); + + if (llc->type != CACHE_TYPE_DATA && llc->type != CACHE_TYPE_UNIFIED) + return; + + nr_shared = cpumask_weight(&llc->shared_cpu_map); + if (nr_shared) + ci->per_cpu_data_slice_size = llc->size / nr_shared; +} + +static void update_per_cpu_data_slice_size(bool cpu_online, unsigned int cpu) +{ + unsigned int icpu; + + for_each_online_cpu(icpu) { + if (!cpu_online && icpu == cpu) + continue; + update_per_cpu_data_slice_size_cpu(icpu); + } +} + static int cacheinfo_cpu_online(unsigned int cpu) { int rc = detect_cache_attributes(cpu); @@ -906,7 +948,11 @@ static int cacheinfo_cpu_online(unsigned int cpu) return rc; rc = cache_add_dev(cpu); if (rc) - free_cache_attributes(cpu); + goto err; + update_per_cpu_data_slice_size(true, cpu); + return 0; +err: + free_cache_attributes(cpu); return rc; } @@ -916,6 +962,7 @@ static int cacheinfo_cpu_pre_down(unsigned int cpu) cpu_cache_sysfs_exit(cpu); free_cache_attributes(cpu); + update_per_cpu_data_slice_size(false, cpu); return 0; } diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h index a5cfd44fab45..d504eb4b49ab 100644 --- a/include/linux/cacheinfo.h +++ b/include/linux/cacheinfo.h @@ -73,6 +73,7 @@ struct cacheinfo { struct cpu_cacheinfo { struct cacheinfo *info_list; + unsigned int per_cpu_data_slice_size; unsigned int num_levels; unsigned int num_leaves; bool cpu_map_populated; -- cgit v1.2.3 From 362d37a106dd3f6431b2fdd91d9208b0d023b50d Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 16 Oct 2023 13:29:56 +0800 Subject: mm, pcp: reduce lock contention for draining high-order pages In commit f26b3fa04611 ("mm/page_alloc: limit number of high-order pages on PCP during bulk free"), the PCP (Per-CPU Pageset) will be drained when PCP is mostly used for high-order pages freeing to improve the cache-hot pages reusing between page allocating and freeing CPUs. On system with small per-CPU data cache slice, pages shouldn't be cached before draining to guarantee cache-hot. But on a system with large per-CPU data cache slice, some pages can be cached before draining to reduce zone lock contention. So, in this patch, instead of draining without any caching, "pcp->batch" pages will be cached in PCP before draining if the size of the per-CPU data cache slice is more than "3 * batch". In theory, if the size of per-CPU data cache slice is more than "2 * batch", we can reuse cache-hot pages between CPUs. But considering the other usage of cache (code, other data accessing, etc.), "3 * batch" is used. Note: "3 * batch" is chosen to make sure the optimization works on recent x86_64 server CPUs. If you want to increase it, please check whether it breaks the optimization. On a 2-socket Intel server with 128 logical CPU, with the patch, the network bandwidth of the UNIX (AF_UNIX) test case of lmbench test suite with 16-pair processes increase 70.5%. The cycles% of the spinlock contention (mostly for zone lock) decreases from 46.1% to 21.3%. The number of PCP draining for high order pages freeing (free_high) decreases 89.9%. The cache miss rate keeps 0.2%. Link: https://lkml.kernel.org/r/20231016053002.756205-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" Acked-by: Mel Gorman Cc: Sudeep Holla Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Johannes Weiner Cc: Dave Hansen Cc: Michal Hocko Cc: Pavel Tatashin Cc: Matthew Wilcox Cc: Christoph Lameter Cc: Arjan van de Ven Signed-off-by: Andrew Morton --- drivers/base/cacheinfo.c | 2 ++ include/linux/gfp.h | 1 + include/linux/mmzone.h | 6 ++++++ mm/page_alloc.c | 38 +++++++++++++++++++++++++++++++++++++- 4 files changed, 46 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index 585c66fce9d9..f1e79263fe61 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -950,6 +950,7 @@ static int cacheinfo_cpu_online(unsigned int cpu) if (rc) goto err; update_per_cpu_data_slice_size(true, cpu); + setup_pcp_cacheinfo(); return 0; err: free_cache_attributes(cpu); @@ -963,6 +964,7 @@ static int cacheinfo_cpu_pre_down(unsigned int cpu) free_cache_attributes(cpu); update_per_cpu_data_slice_size(false, cpu); + setup_pcp_cacheinfo(); return 0; } diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 665f06675c83..665edc11fb9f 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -325,6 +325,7 @@ void drain_all_pages(struct zone *zone); void drain_local_pages(struct zone *zone); void page_alloc_init_late(void); +void setup_pcp_cacheinfo(void); /* * gfp_allowed_mask is set to GFP_BOOT_MASK during early boot to restrict what diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index de313f1c15f9..efe72b3f7872 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -680,8 +680,14 @@ enum zone_watermarks { * PCPF_PREV_FREE_HIGH_ORDER: a high-order page is freed in the * previous page freeing. To avoid to drain PCP for an accident * high-order page freeing. + * + * PCPF_FREE_HIGH_BATCH: preserve "pcp->batch" pages in PCP before + * draining PCP for consecutive high-order pages freeing without + * allocation if data cache slice of CPU is large enough. To reduce + * zone lock contention and keep cache-hot pages reusing. */ #define PCPF_PREV_FREE_HIGH_ORDER BIT(0) +#define PCPF_FREE_HIGH_BATCH BIT(1) struct per_cpu_pages { spinlock_t lock; /* Protects lists field */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index de547ef9a9ad..b76b1de48a30 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -52,6 +52,7 @@ #include #include #include +#include #include #include "internal.h" #include "shuffle.h" @@ -2385,7 +2386,9 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, */ if (order && order <= PAGE_ALLOC_COSTLY_ORDER) { free_high = (pcp->free_factor && - (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER)); + (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) && + (!(pcp->flags & PCPF_FREE_HIGH_BATCH) || + pcp->count >= READ_ONCE(pcp->batch))); pcp->flags |= PCPF_PREV_FREE_HIGH_ORDER; } else if (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) { pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER; @@ -5418,6 +5421,39 @@ static void zone_pcp_update(struct zone *zone, int cpu_online) mutex_unlock(&pcp_batch_high_lock); } +static void zone_pcp_update_cacheinfo(struct zone *zone) +{ + int cpu; + struct per_cpu_pages *pcp; + struct cpu_cacheinfo *cci; + + for_each_online_cpu(cpu) { + pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); + cci = get_cpu_cacheinfo(cpu); + /* + * If data cache slice of CPU is large enough, "pcp->batch" + * pages can be preserved in PCP before draining PCP for + * consecutive high-order pages freeing without allocation. + * This can reduce zone lock contention without hurting + * cache-hot pages sharing. + */ + spin_lock(&pcp->lock); + if ((cci->per_cpu_data_slice_size >> PAGE_SHIFT) > 3 * pcp->batch) + pcp->flags |= PCPF_FREE_HIGH_BATCH; + else + pcp->flags &= ~PCPF_FREE_HIGH_BATCH; + spin_unlock(&pcp->lock); + } +} + +void setup_pcp_cacheinfo(void) +{ + struct zone *zone; + + for_each_populated_zone(zone) + zone_pcp_update_cacheinfo(zone); +} + /* * Allocate per cpu pagesets and initialize them. * Before this call only boot pagesets were available. -- cgit v1.2.3 From c0a242394cb980bd00e1f61dc8aacb453d2bbe6a Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 16 Oct 2023 13:29:58 +0800 Subject: mm, page_alloc: scale the number of pages that are batch allocated When a task is allocating a large number of order-0 pages, it may acquire the zone->lock multiple times allocating pages in batches. This may unnecessarily contend on the zone lock when allocating very large number of pages. This patch adapts the size of the batch based on the recent pattern to scale the batch size for subsequent allocations. On a 2-socket Intel server with 224 logical CPU, we run 8 kbuild instances in parallel (each with `make -j 28`) in 8 cgroup. This simulates the kbuild server that is used by 0-Day kbuild service. With the patch, the cycles% of the spinlock contention (mostly for zone lock) decreases from 12.6% to 11.0% (with PCP size == 367). Link: https://lkml.kernel.org/r/20231016053002.756205-6-ying.huang@intel.com Signed-off-by: "Huang, Ying" Suggested-by: Mel Gorman Acked-by: Mel Gorman Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Johannes Weiner Cc: Dave Hansen Cc: Michal Hocko Cc: Pavel Tatashin Cc: Matthew Wilcox Cc: Christoph Lameter Cc: Arjan van de Ven Cc: Sudeep Holla Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 3 ++- mm/page_alloc.c | 53 ++++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 45 insertions(+), 11 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index efe72b3f7872..e6cc2238c65f 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -695,9 +695,10 @@ struct per_cpu_pages { int high; /* high watermark, emptying needed */ int batch; /* chunk size for buddy add/remove */ u8 flags; /* protected by pcp->lock */ + u8 alloc_factor; /* batch scaling factor during allocate */ u8 free_factor; /* batch scaling factor during free */ #ifdef CONFIG_NUMA - short expire; /* When 0, remote pagesets are drained */ + u8 expire; /* When 0, remote pagesets are drained */ #endif /* Lists of pages, one per migrate type stored on the pcp-lists */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 05a8d34827d2..6f6af835b05b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2373,6 +2373,12 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, int pindex; bool free_high = false; + /* + * On freeing, reduce the number of pages that are batch allocated. + * See nr_pcp_alloc() where alloc_factor is increased for subsequent + * allocations. + */ + pcp->alloc_factor >>= 1; __count_vm_events(PGFREE, 1 << order); pindex = order_to_pindex(migratetype, order); list_add(&page->pcp_list, &pcp->lists[pindex]); @@ -2679,6 +2685,42 @@ struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone, return page; } +static int nr_pcp_alloc(struct per_cpu_pages *pcp, int order) +{ + int high, batch, max_nr_alloc; + + high = READ_ONCE(pcp->high); + batch = READ_ONCE(pcp->batch); + + /* Check for PCP disabled or boot pageset */ + if (unlikely(high < batch)) + return 1; + + /* + * Double the number of pages allocated each time there is subsequent + * allocation of order-0 pages without any freeing. + */ + if (!order) { + max_nr_alloc = max(high - pcp->count - batch, batch); + batch <<= pcp->alloc_factor; + if (batch <= max_nr_alloc && + pcp->alloc_factor < CONFIG_PCP_BATCH_SCALE_MAX) + pcp->alloc_factor++; + batch = min(batch, max_nr_alloc); + } + + /* + * Scale batch relative to order if batch implies free pages + * can be stored on the PCP. Batch can be 1 for small zones or + * for boot pagesets which should never store free pages as + * the pages may belong to arbitrary zones. + */ + if (batch > 1) + batch = max(batch >> order, 2); + + return batch; +} + /* Remove page from the per-cpu list, caller must protect the list */ static inline struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order, @@ -2691,18 +2733,9 @@ struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order, do { if (list_empty(list)) { - int batch = READ_ONCE(pcp->batch); + int batch = nr_pcp_alloc(pcp, order); int alloced; - /* - * Scale batch relative to order if batch implies - * free pages can be stored on the PCP. Batch can - * be 1 for small zones or for boot pagesets which - * should never store free pages as the pages may - * belong to arbitrary zones. - */ - if (batch > 1) - batch = max(batch >> order, 2); alloced = rmqueue_bulk(zone, order, batch, list, migratetype, alloc_flags); -- cgit v1.2.3 From 90b41691b9881376fe784e13b5766ec3676fdb55 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 16 Oct 2023 13:29:59 +0800 Subject: mm: add framework for PCP high auto-tuning The page allocation performance requirements of different workloads are usually different. So, we need to tune PCP (per-CPU pageset) high to optimize the workload page allocation performance. Now, we have a system wide sysctl knob (percpu_pagelist_high_fraction) to tune PCP high by hand. But, it's hard to find out the best value by hand. And one global configuration may not work best for the different workloads that run on the same system. One solution to these issues is to tune PCP high of each CPU automatically. This patch adds the framework for PCP high auto-tuning. With it, pcp->high of each CPU will be changed automatically by tuning algorithm at runtime. The minimal high (pcp->high_min) is the original PCP high value calculated based on the low watermark pages. While the maximal high (pcp->high_max) is the PCP high value when percpu_pagelist_high_fraction sysctl knob is set to MIN_PERCPU_PAGELIST_HIGH_FRACTION. That is, the maximal pcp->high that can be set via sysctl knob by hand. It's possible that PCP high auto-tuning doesn't work well for some workloads. So, when PCP high is tuned by hand via the sysctl knob, the auto-tuning will be disabled. The PCP high set by hand will be used instead. This patch only adds the framework, so pcp->high will be set to pcp->high_min (original default) always. We will add actual auto-tuning algorithm in the following patches in the series. Link: https://lkml.kernel.org/r/20231016053002.756205-7-ying.huang@intel.com Signed-off-by: "Huang, Ying" Acked-by: Mel Gorman Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Johannes Weiner Cc: Dave Hansen Cc: Michal Hocko Cc: Pavel Tatashin Cc: Matthew Wilcox Cc: Christoph Lameter Cc: Arjan van de Ven Cc: Sudeep Holla Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 5 +++- mm/page_alloc.c | 71 ++++++++++++++++++++++++++++++++------------------ 2 files changed, 50 insertions(+), 26 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index e6cc2238c65f..775abc899e80 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -693,6 +693,8 @@ struct per_cpu_pages { spinlock_t lock; /* Protects lists field */ int count; /* number of pages in the list */ int high; /* high watermark, emptying needed */ + int high_min; /* min high watermark */ + int high_max; /* max high watermark */ int batch; /* chunk size for buddy add/remove */ u8 flags; /* protected by pcp->lock */ u8 alloc_factor; /* batch scaling factor during allocate */ @@ -852,7 +854,8 @@ struct zone { * the high and batch values are copied to individual pagesets for * faster access */ - int pageset_high; + int pageset_high_min; + int pageset_high_max; int pageset_batch; #ifndef CONFIG_SPARSEMEM diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6f6af835b05b..922836b6a01d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2350,7 +2350,7 @@ static int nr_pcp_free(struct per_cpu_pages *pcp, int high, bool free_high) static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone, bool free_high) { - int high = READ_ONCE(pcp->high); + int high = READ_ONCE(pcp->high_min); if (unlikely(!high || free_high)) return 0; @@ -2689,7 +2689,7 @@ static int nr_pcp_alloc(struct per_cpu_pages *pcp, int order) { int high, batch, max_nr_alloc; - high = READ_ONCE(pcp->high); + high = READ_ONCE(pcp->high_min); batch = READ_ONCE(pcp->batch); /* Check for PCP disabled or boot pageset */ @@ -5296,14 +5296,15 @@ static int zone_batchsize(struct zone *zone) } static int percpu_pagelist_high_fraction; -static int zone_highsize(struct zone *zone, int batch, int cpu_online) +static int zone_highsize(struct zone *zone, int batch, int cpu_online, + int high_fraction) { #ifdef CONFIG_MMU int high; int nr_split_cpus; unsigned long total_pages; - if (!percpu_pagelist_high_fraction) { + if (!high_fraction) { /* * By default, the high value of the pcp is based on the zone * low watermark so that if they are full then background @@ -5316,15 +5317,15 @@ static int zone_highsize(struct zone *zone, int batch, int cpu_online) * value is based on a fraction of the managed pages in the * zone. */ - total_pages = zone_managed_pages(zone) / percpu_pagelist_high_fraction; + total_pages = zone_managed_pages(zone) / high_fraction; } /* * Split the high value across all online CPUs local to the zone. Note * that early in boot that CPUs may not be online yet and that during * CPU hotplug that the cpumask is not yet updated when a CPU is being - * onlined. For memory nodes that have no CPUs, split pcp->high across - * all online CPUs to mitigate the risk that reclaim is triggered + * onlined. For memory nodes that have no CPUs, split the high value + * across all online CPUs to mitigate the risk that reclaim is triggered * prematurely due to pages stored on pcp lists. */ nr_split_cpus = cpumask_weight(cpumask_of_node(zone_to_nid(zone))) + cpu_online; @@ -5352,19 +5353,21 @@ static int zone_highsize(struct zone *zone, int batch, int cpu_online) * However, guaranteeing these relations at all times would require e.g. write * barriers here but also careful usage of read barriers at the read side, and * thus be prone to error and bad for performance. Thus the update only prevents - * store tearing. Any new users of pcp->batch and pcp->high should ensure they - * can cope with those fields changing asynchronously, and fully trust only the - * pcp->count field on the local CPU with interrupts disabled. + * store tearing. Any new users of pcp->batch, pcp->high_min and pcp->high_max + * should ensure they can cope with those fields changing asynchronously, and + * fully trust only the pcp->count field on the local CPU with interrupts + * disabled. * * mutex_is_locked(&pcp_batch_high_lock) required when calling this function * outside of boot time (or some other assurance that no concurrent updaters * exist). */ -static void pageset_update(struct per_cpu_pages *pcp, unsigned long high, - unsigned long batch) +static void pageset_update(struct per_cpu_pages *pcp, unsigned long high_min, + unsigned long high_max, unsigned long batch) { WRITE_ONCE(pcp->batch, batch); - WRITE_ONCE(pcp->high, high); + WRITE_ONCE(pcp->high_min, high_min); + WRITE_ONCE(pcp->high_max, high_max); } static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats) @@ -5384,20 +5387,21 @@ static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonesta * need to be as careful as pageset_update() as nobody can access the * pageset yet. */ - pcp->high = BOOT_PAGESET_HIGH; + pcp->high_min = BOOT_PAGESET_HIGH; + pcp->high_max = BOOT_PAGESET_HIGH; pcp->batch = BOOT_PAGESET_BATCH; pcp->free_factor = 0; } -static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high, - unsigned long batch) +static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high_min, + unsigned long high_max, unsigned long batch) { struct per_cpu_pages *pcp; int cpu; for_each_possible_cpu(cpu) { pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); - pageset_update(pcp, high, batch); + pageset_update(pcp, high_min, high_max, batch); } } @@ -5407,19 +5411,34 @@ static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long h */ static void zone_set_pageset_high_and_batch(struct zone *zone, int cpu_online) { - int new_high, new_batch; + int new_high_min, new_high_max, new_batch; new_batch = max(1, zone_batchsize(zone)); - new_high = zone_highsize(zone, new_batch, cpu_online); + if (percpu_pagelist_high_fraction) { + new_high_min = zone_highsize(zone, new_batch, cpu_online, + percpu_pagelist_high_fraction); + /* + * PCP high is tuned manually, disable auto-tuning via + * setting high_min and high_max to the manual value. + */ + new_high_max = new_high_min; + } else { + new_high_min = zone_highsize(zone, new_batch, cpu_online, 0); + new_high_max = zone_highsize(zone, new_batch, cpu_online, + MIN_PERCPU_PAGELIST_HIGH_FRACTION); + } - if (zone->pageset_high == new_high && + if (zone->pageset_high_min == new_high_min && + zone->pageset_high_max == new_high_max && zone->pageset_batch == new_batch) return; - zone->pageset_high = new_high; + zone->pageset_high_min = new_high_min; + zone->pageset_high_max = new_high_max; zone->pageset_batch = new_batch; - __zone_set_pageset_high_and_batch(zone, new_high, new_batch); + __zone_set_pageset_high_and_batch(zone, new_high_min, new_high_max, + new_batch); } void __meminit setup_zone_pageset(struct zone *zone) @@ -5528,7 +5547,8 @@ __meminit void zone_pcp_init(struct zone *zone) */ zone->per_cpu_pageset = &boot_pageset; zone->per_cpu_zonestats = &boot_zonestats; - zone->pageset_high = BOOT_PAGESET_HIGH; + zone->pageset_high_min = BOOT_PAGESET_HIGH; + zone->pageset_high_max = BOOT_PAGESET_HIGH; zone->pageset_batch = BOOT_PAGESET_BATCH; if (populated_zone(zone)) @@ -6430,13 +6450,14 @@ EXPORT_SYMBOL(free_contig_range); void zone_pcp_disable(struct zone *zone) { mutex_lock(&pcp_batch_high_lock); - __zone_set_pageset_high_and_batch(zone, 0, 1); + __zone_set_pageset_high_and_batch(zone, 0, 0, 1); __drain_all_pages(zone, true); } void zone_pcp_enable(struct zone *zone) { - __zone_set_pageset_high_and_batch(zone, zone->pageset_high, zone->pageset_batch); + __zone_set_pageset_high_and_batch(zone, zone->pageset_high_min, + zone->pageset_high_max, zone->pageset_batch); mutex_unlock(&pcp_batch_high_lock); } -- cgit v1.2.3 From 51a755c56dc05a8b31ed28d24f28354946dc7529 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 16 Oct 2023 13:30:00 +0800 Subject: mm: tune PCP high automatically The target to tune PCP high automatically is as follows, - Minimize allocation/freeing from/to shared zone - Minimize idle pages in PCP - Minimize pages in PCP if the system free pages is too few To reach these target, a tuning algorithm as follows is designed, - When we refill PCP via allocating from the zone, increase PCP high. Because if we had larger PCP, we could avoid to allocate from the zone. - In periodic vmstat updating kworker (via refresh_cpu_vm_stats()), decrease PCP high to try to free possible idle PCP pages. - When page reclaiming is active for the zone, stop increasing PCP high in allocating path, decrease PCP high and free some pages in freeing path. So, the PCP high can be tuned to the page allocating/freeing depth of workloads eventually. One issue of the algorithm is that if the number of pages allocated is much more than that of pages freed on a CPU, the PCP high may become the maximal value even if the allocating/freeing depth is small. But this isn't a severe issue, because there are no idle pages in this case. One alternative choice is to increase PCP high when we drain PCP via trying to free pages to the zone, but don't increase PCP high during PCP refilling. This can avoid the issue above. But if the number of pages allocated is much less than that of pages freed on a CPU, there will be many idle pages in PCP and it is hard to free these idle pages. 1/8 (>> 3) of PCP high will be decreased periodically. The value 1/8 is kind of arbitrary. Just to make sure that the idle PCP pages will be freed eventually. On a 2-socket Intel server with 224 logical CPU, we run 8 kbuild instances in parallel (each with `make -j 28`) in 8 cgroup. This simulates the kbuild server that is used by 0-Day kbuild service. With the patch, the build time decreases 3.5%. The cycles% of the spinlock contention (mostly for zone lock) decreases from 11.0% to 0.5%. The number of PCP draining for high order pages freeing (free_high) decreases 65.6%. The number of pages allocated from zone (instead of from PCP) decreases 83.9%. Link: https://lkml.kernel.org/r/20231016053002.756205-8-ying.huang@intel.com Signed-off-by: "Huang, Ying" Suggested-by: Mel Gorman Suggested-by: Michal Hocko Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Johannes Weiner Cc: Dave Hansen Cc: Pavel Tatashin Cc: Matthew Wilcox Cc: Christoph Lameter Cc: Arjan van de Ven Cc: Sudeep Holla Signed-off-by: Andrew Morton --- include/linux/gfp.h | 1 + mm/page_alloc.c | 119 +++++++++++++++++++++++++++++++++++++++++----------- mm/vmstat.c | 8 ++-- 3 files changed, 99 insertions(+), 29 deletions(-) (limited to 'include/linux') diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 665edc11fb9f..5b917e5b9350 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -320,6 +320,7 @@ extern void page_frag_free(void *addr); #define free_page(addr) free_pages((addr), 0) void page_alloc_init_cpuhp(void); +int decay_pcp_high(struct zone *zone, struct per_cpu_pages *pcp); void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp); void drain_all_pages(struct zone *zone); void drain_local_pages(struct zone *zone); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 922836b6a01d..83af76a8cef9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2157,6 +2157,40 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, return i; } +/* + * Called from the vmstat counter updater to decay the PCP high. + * Return whether there are addition works to do. + */ +int decay_pcp_high(struct zone *zone, struct per_cpu_pages *pcp) +{ + int high_min, to_drain, batch; + int todo = 0; + + high_min = READ_ONCE(pcp->high_min); + batch = READ_ONCE(pcp->batch); + /* + * Decrease pcp->high periodically to try to free possible + * idle PCP pages. And, avoid to free too many pages to + * control latency. This caps pcp->high decrement too. + */ + if (pcp->high > high_min) { + pcp->high = max3(pcp->count - (batch << CONFIG_PCP_BATCH_SCALE_MAX), + pcp->high - (pcp->high >> 3), high_min); + if (pcp->high > high_min) + todo++; + } + + to_drain = pcp->count - pcp->high; + if (to_drain > 0) { + spin_lock(&pcp->lock); + free_pcppages_bulk(zone, to_drain, pcp, 0); + spin_unlock(&pcp->lock); + todo++; + } + + return todo; +} + #ifdef CONFIG_NUMA /* * Called from the vmstat counter updater to drain pagesets of this @@ -2318,14 +2352,13 @@ static bool free_unref_page_prepare(struct page *page, unsigned long pfn, return true; } -static int nr_pcp_free(struct per_cpu_pages *pcp, int high, bool free_high) +static int nr_pcp_free(struct per_cpu_pages *pcp, int batch, int high, bool free_high) { int min_nr_free, max_nr_free; - int batch = READ_ONCE(pcp->batch); - /* Free everything if batch freeing high-order pages. */ + /* Free as much as possible if batch freeing high-order pages. */ if (unlikely(free_high)) - return pcp->count; + return min(pcp->count, batch << CONFIG_PCP_BATCH_SCALE_MAX); /* Check for PCP disabled or boot pageset */ if (unlikely(high < batch)) @@ -2340,7 +2373,7 @@ static int nr_pcp_free(struct per_cpu_pages *pcp, int high, bool free_high) * freeing of pages without any allocation. */ batch <<= pcp->free_factor; - if (batch < max_nr_free && pcp->free_factor < CONFIG_PCP_BATCH_SCALE_MAX) + if (batch <= max_nr_free && pcp->free_factor < CONFIG_PCP_BATCH_SCALE_MAX) pcp->free_factor++; batch = clamp(batch, min_nr_free, max_nr_free); @@ -2348,28 +2381,48 @@ static int nr_pcp_free(struct per_cpu_pages *pcp, int high, bool free_high) } static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone, - bool free_high) + int batch, bool free_high) { - int high = READ_ONCE(pcp->high_min); + int high, high_min, high_max; + + high_min = READ_ONCE(pcp->high_min); + high_max = READ_ONCE(pcp->high_max); + high = pcp->high = clamp(pcp->high, high_min, high_max); - if (unlikely(!high || free_high)) + if (unlikely(!high)) return 0; - if (!test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) - return high; + if (unlikely(free_high)) { + pcp->high = max(high - (batch << CONFIG_PCP_BATCH_SCALE_MAX), + high_min); + return 0; + } /* * If reclaim is active, limit the number of pages that can be * stored on pcp lists */ - return min(READ_ONCE(pcp->batch) << 2, high); + if (test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) { + pcp->high = max(high - (batch << pcp->free_factor), high_min); + return min(batch << 2, pcp->high); + } + + if (pcp->count >= high && high_min != high_max) { + int need_high = (batch << pcp->free_factor) + batch; + + /* pcp->high should be large enough to hold batch freed pages */ + if (pcp->high < need_high) + pcp->high = clamp(need_high, high_min, high_max); + } + + return high; } static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, struct page *page, int migratetype, unsigned int order) { - int high; + int high, batch; int pindex; bool free_high = false; @@ -2384,6 +2437,7 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, list_add(&page->pcp_list, &pcp->lists[pindex]); pcp->count += 1 << order; + batch = READ_ONCE(pcp->batch); /* * As high-order pages other than THP's stored on PCP can contribute * to fragmentation, limit the number stored when PCP is heavily @@ -2394,14 +2448,15 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, free_high = (pcp->free_factor && (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) && (!(pcp->flags & PCPF_FREE_HIGH_BATCH) || - pcp->count >= READ_ONCE(pcp->batch))); + pcp->count >= READ_ONCE(batch))); pcp->flags |= PCPF_PREV_FREE_HIGH_ORDER; } else if (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) { pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER; } - high = nr_pcp_high(pcp, zone, free_high); + high = nr_pcp_high(pcp, zone, batch, free_high); if (pcp->count >= high) { - free_pcppages_bulk(zone, nr_pcp_free(pcp, high, free_high), pcp, pindex); + free_pcppages_bulk(zone, nr_pcp_free(pcp, batch, high, free_high), + pcp, pindex); } } @@ -2685,24 +2740,38 @@ struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone, return page; } -static int nr_pcp_alloc(struct per_cpu_pages *pcp, int order) +static int nr_pcp_alloc(struct per_cpu_pages *pcp, struct zone *zone, int order) { - int high, batch, max_nr_alloc; + int high, base_batch, batch, max_nr_alloc; + int high_max, high_min; - high = READ_ONCE(pcp->high_min); - batch = READ_ONCE(pcp->batch); + base_batch = READ_ONCE(pcp->batch); + high_min = READ_ONCE(pcp->high_min); + high_max = READ_ONCE(pcp->high_max); + high = pcp->high = clamp(pcp->high, high_min, high_max); /* Check for PCP disabled or boot pageset */ - if (unlikely(high < batch)) + if (unlikely(high < base_batch)) return 1; + if (order) + batch = base_batch; + else + batch = (base_batch << pcp->alloc_factor); + /* - * Double the number of pages allocated each time there is subsequent - * allocation of order-0 pages without any freeing. + * If we had larger pcp->high, we could avoid to allocate from + * zone. */ + if (high_min != high_max && !test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) + high = pcp->high = min(high + batch, high_max); + if (!order) { - max_nr_alloc = max(high - pcp->count - batch, batch); - batch <<= pcp->alloc_factor; + max_nr_alloc = max(high - pcp->count - base_batch, base_batch); + /* + * Double the number of pages allocated each time there is + * subsequent allocation of order-0 pages without any freeing. + */ if (batch <= max_nr_alloc && pcp->alloc_factor < CONFIG_PCP_BATCH_SCALE_MAX) pcp->alloc_factor++; @@ -2733,7 +2802,7 @@ struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order, do { if (list_empty(list)) { - int batch = nr_pcp_alloc(pcp, order); + int batch = nr_pcp_alloc(pcp, zone, order); int alloced; alloced = rmqueue_bulk(zone, order, diff --git a/mm/vmstat.c b/mm/vmstat.c index 88ea95d4221c..359460deb377 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -816,9 +816,7 @@ static int refresh_cpu_vm_stats(bool do_pagesets) for_each_populated_zone(zone) { struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats; -#ifdef CONFIG_NUMA struct per_cpu_pages __percpu *pcp = zone->per_cpu_pageset; -#endif for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) { int v; @@ -834,10 +832,12 @@ static int refresh_cpu_vm_stats(bool do_pagesets) #endif } } -#ifdef CONFIG_NUMA if (do_pagesets) { cond_resched(); + + changes += decay_pcp_high(zone, this_cpu_ptr(pcp)); +#ifdef CONFIG_NUMA /* * Deal with draining the remote pageset of this * processor @@ -866,8 +866,8 @@ static int refresh_cpu_vm_stats(bool do_pagesets) drain_zone_pages(zone, this_cpu_ptr(pcp)); changes++; } - } #endif + } } for_each_online_pgdat(pgdat) { -- cgit v1.2.3 From 57c0419c5f0ea2ccab8700895c8fac20ba1eb21f Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 16 Oct 2023 13:30:01 +0800 Subject: mm, pcp: decrease PCP high if free pages < high watermark One target of PCP is to minimize pages in PCP if the system free pages is too few. To reach that target, when page reclaiming is active for the zone (ZONE_RECLAIM_ACTIVE), we will stop increasing PCP high in allocating path, decrease PCP high and free some pages in freeing path. But this may be too late because the background page reclaiming may introduce latency for some workloads. So, in this patch, during page allocation we will detect whether the number of free pages of the zone is below high watermark. If so, we will stop increasing PCP high in allocating path, decrease PCP high and free some pages in freeing path. With this, we can reduce the possibility of the premature background page reclaiming caused by too large PCP. The high watermark checking is done in allocating path to reduce the overhead in hotter freeing path. Link: https://lkml.kernel.org/r/20231016053002.756205-9-ying.huang@intel.com Signed-off-by: "Huang, Ying" Cc: Mel Gorman Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Johannes Weiner Cc: Dave Hansen Cc: Michal Hocko Cc: Pavel Tatashin Cc: Matthew Wilcox Cc: Christoph Lameter Cc: Arjan van de Ven Cc: Sudeep Holla Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 1 + mm/page_alloc.c | 33 +++++++++++++++++++++++++++++++-- 2 files changed, 32 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 775abc899e80..b92ab001e146 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1016,6 +1016,7 @@ enum zone_flags { * Cleared when kswapd is woken. */ ZONE_RECLAIM_ACTIVE, /* kswapd may be scanning the zone. */ + ZONE_BELOW_HIGH, /* zone is below high watermark. */ }; static inline unsigned long zone_managed_pages(struct zone *zone) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 83af76a8cef9..58ab8389da05 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2407,7 +2407,13 @@ static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone, return min(batch << 2, pcp->high); } - if (pcp->count >= high && high_min != high_max) { + if (high_min == high_max) + return high; + + if (test_bit(ZONE_BELOW_HIGH, &zone->flags)) { + pcp->high = max(high - (batch << pcp->free_factor), high_min); + high = max(pcp->count, high_min); + } else if (pcp->count >= high) { int need_high = (batch << pcp->free_factor) + batch; /* pcp->high should be large enough to hold batch freed pages */ @@ -2457,6 +2463,10 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, if (pcp->count >= high) { free_pcppages_bulk(zone, nr_pcp_free(pcp, batch, high, free_high), pcp, pindex); + if (test_bit(ZONE_BELOW_HIGH, &zone->flags) && + zone_watermark_ok(zone, 0, high_wmark_pages(zone), + ZONE_MOVABLE, 0)) + clear_bit(ZONE_BELOW_HIGH, &zone->flags); } } @@ -2763,7 +2773,7 @@ static int nr_pcp_alloc(struct per_cpu_pages *pcp, struct zone *zone, int order) * If we had larger pcp->high, we could avoid to allocate from * zone. */ - if (high_min != high_max && !test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) + if (high_min != high_max && !test_bit(ZONE_BELOW_HIGH, &zone->flags)) high = pcp->high = min(high + batch, high_max); if (!order) { @@ -3225,6 +3235,25 @@ retry: } } + /* + * Detect whether the number of free pages is below high + * watermark. If so, we will decrease pcp->high and free + * PCP pages in free path to reduce the possibility of + * premature page reclaiming. Detection is done here to + * avoid to do that in hotter free path. + */ + if (test_bit(ZONE_BELOW_HIGH, &zone->flags)) + goto check_alloc_wmark; + + mark = high_wmark_pages(zone); + if (zone_watermark_fast(zone, order, mark, + ac->highest_zoneidx, alloc_flags, + gfp_mask)) + goto try_this_zone; + else + set_bit(ZONE_BELOW_HIGH, &zone->flags); + +check_alloc_wmark: mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK); if (!zone_watermark_fast(zone, order, mark, ac->highest_zoneidx, alloc_flags, -- cgit v1.2.3 From 6ccdcb6d3a741c4e005ca6ffd4a62ddf8b5bead3 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 16 Oct 2023 13:30:02 +0800 Subject: mm, pcp: reduce detecting time of consecutive high order page freeing In current PCP auto-tuning design, if the number of pages allocated is much more than that of pages freed on a CPU, the PCP high may become the maximal value even if the allocating/freeing depth is small, for example, in the sender of network workloads. If a CPU was used as sender originally, then it is used as receiver after context switching, we need to fill the whole PCP with maximal high before triggering PCP draining for consecutive high order freeing. This will hurt the performance of some network workloads. To solve the issue, in this patch, we will track the consecutive page freeing with a counter in stead of relying on PCP draining. So, we can detect consecutive page freeing much earlier. On a 2-socket Intel server with 128 logical CPU, we tested SCTP_STREAM_MANY test case of netperf test suite with 64-pair processes. With the patch, the network bandwidth improves 5.0%. This restores the performance drop caused by PCP auto-tuning. Link: https://lkml.kernel.org/r/20231016053002.756205-10-ying.huang@intel.com Signed-off-by: "Huang, Ying" Cc: Mel Gorman Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Johannes Weiner Cc: Dave Hansen Cc: Michal Hocko Cc: Pavel Tatashin Cc: Matthew Wilcox Cc: Christoph Lameter Cc: Arjan van de Ven Cc: Sudeep Holla Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 2 +- mm/page_alloc.c | 27 +++++++++++++++------------ 2 files changed, 16 insertions(+), 13 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index b92ab001e146..3c25226beeed 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -698,10 +698,10 @@ struct per_cpu_pages { int batch; /* chunk size for buddy add/remove */ u8 flags; /* protected by pcp->lock */ u8 alloc_factor; /* batch scaling factor during allocate */ - u8 free_factor; /* batch scaling factor during free */ #ifdef CONFIG_NUMA u8 expire; /* When 0, remote pagesets are drained */ #endif + short free_count; /* consecutive free count */ /* Lists of pages, one per migrate type stored on the pcp-lists */ struct list_head lists[NR_PCP_LISTS]; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 58ab8389da05..d52718284029 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2369,13 +2369,10 @@ static int nr_pcp_free(struct per_cpu_pages *pcp, int batch, int high, bool free max_nr_free = high - batch; /* - * Double the number of pages freed each time there is subsequent - * freeing of pages without any allocation. + * Increase the batch number to the number of the consecutive + * freed pages to reduce zone lock contention. */ - batch <<= pcp->free_factor; - if (batch <= max_nr_free && pcp->free_factor < CONFIG_PCP_BATCH_SCALE_MAX) - pcp->free_factor++; - batch = clamp(batch, min_nr_free, max_nr_free); + batch = clamp_t(int, pcp->free_count, min_nr_free, max_nr_free); return batch; } @@ -2403,7 +2400,9 @@ static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone, * stored on pcp lists */ if (test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags)) { - pcp->high = max(high - (batch << pcp->free_factor), high_min); + int free_count = max_t(int, pcp->free_count, batch); + + pcp->high = max(high - free_count, high_min); return min(batch << 2, pcp->high); } @@ -2411,10 +2410,12 @@ static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone, return high; if (test_bit(ZONE_BELOW_HIGH, &zone->flags)) { - pcp->high = max(high - (batch << pcp->free_factor), high_min); + int free_count = max_t(int, pcp->free_count, batch); + + pcp->high = max(high - free_count, high_min); high = max(pcp->count, high_min); } else if (pcp->count >= high) { - int need_high = (batch << pcp->free_factor) + batch; + int need_high = pcp->free_count + batch; /* pcp->high should be large enough to hold batch freed pages */ if (pcp->high < need_high) @@ -2451,7 +2452,7 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, * stops will be drained from vmstat refresh context. */ if (order && order <= PAGE_ALLOC_COSTLY_ORDER) { - free_high = (pcp->free_factor && + free_high = (pcp->free_count >= batch && (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) && (!(pcp->flags & PCPF_FREE_HIGH_BATCH) || pcp->count >= READ_ONCE(batch))); @@ -2459,6 +2460,8 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp, } else if (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) { pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER; } + if (pcp->free_count < (batch << CONFIG_PCP_BATCH_SCALE_MAX)) + pcp->free_count += (1 << order); high = nr_pcp_high(pcp, zone, batch, free_high); if (pcp->count >= high) { free_pcppages_bulk(zone, nr_pcp_free(pcp, batch, high, free_high), @@ -2855,7 +2858,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone, * See nr_pcp_free() where free_factor is increased for subsequent * frees. */ - pcp->free_factor >>= 1; + pcp->free_count >>= 1; list = &pcp->lists[order_to_pindex(migratetype, order)]; page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp, list); pcp_spin_unlock(pcp); @@ -5488,7 +5491,7 @@ static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonesta pcp->high_min = BOOT_PAGESET_HIGH; pcp->high_max = BOOT_PAGESET_HIGH; pcp->batch = BOOT_PAGESET_BATCH; - pcp->free_factor = 0; + pcp->free_count = 0; } static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high_min, -- cgit v1.2.3 From 1aacbd354313f25c855e662e41c04e2abf71444a Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 19 Oct 2023 15:53:42 -0700 Subject: mm: kmem: add direct objcg pointer to task_struct To charge a freshly allocated kernel object to a memory cgroup, the kernel needs to obtain an objcg pointer. Currently it does it indirectly by obtaining the memcg pointer first and then calling to __get_obj_cgroup_from_memcg(). Usually tasks spend their entire life belonging to the same object cgroup. So it makes sense to save the objcg pointer on task_struct directly, so it can be obtained faster. It requires some work on fork, exit and cgroup migrate paths, but these paths are way colder. To avoid any costly synchronization the following rules are applied: 1) A task sets it's objcg pointer itself. 2) If a task is being migrated to another cgroup, the least significant bit of the objcg pointer is set atomically. 3) On the allocation path the objcg pointer is obtained locklessly using the READ_ONCE() macro and the least significant bit is checked. If it's set, the following procedure is used to update it locklessly: - task->objcg is zeroed using cmpxcg - new objcg pointer is obtained - task->objcg is updated using try_cmpxchg - operation is repeated if try_cmpxcg fails It guarantees that no updates will be lost if task migration is racing against objcg pointer update. It also allows to keep both read and write paths fully lockless. Because the task is keeping a reference to the objcg, it can't go away while the task is alive. This commit doesn't change the way the remote memcg charging works. Link: https://lkml.kernel.org/r/20231019225346.1822282-3-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin (Cruise) Tested-by: Naresh Kamboju Acked-by: Johannes Weiner Acked-by: Shakeel Butt Reviewed-by: Vlastimil Babka Cc: David Rientjes Cc: Dennis Zhou Cc: Michal Hocko Cc: Muchun Song Signed-off-by: Andrew Morton --- include/linux/sched.h | 4 ++ mm/memcontrol.c | 139 ++++++++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 134 insertions(+), 9 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index 77f01ac385f7..60de42715b56 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1443,6 +1443,10 @@ struct task_struct { struct mem_cgroup *active_memcg; #endif +#ifdef CONFIG_MEMCG_KMEM + struct obj_cgroup *objcg; +#endif + #ifdef CONFIG_BLK_CGROUP struct gendisk *throttle_disk; #endif diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 975ba766c16f..96f4c319f025 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -249,6 +249,9 @@ struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr) return container_of(vmpr, struct mem_cgroup, vmpressure); } +#define CURRENT_OBJCG_UPDATE_BIT 0 +#define CURRENT_OBJCG_UPDATE_FLAG (1UL << CURRENT_OBJCG_UPDATE_BIT) + #ifdef CONFIG_MEMCG_KMEM static DEFINE_SPINLOCK(objcg_lock); @@ -3083,6 +3086,58 @@ static struct obj_cgroup *__get_obj_cgroup_from_memcg(struct mem_cgroup *memcg) return objcg; } +static struct obj_cgroup *current_objcg_update(void) +{ + struct mem_cgroup *memcg; + struct obj_cgroup *old, *objcg = NULL; + + do { + /* Atomically drop the update bit. */ + old = xchg(¤t->objcg, NULL); + if (old) { + old = (struct obj_cgroup *) + ((unsigned long)old & ~CURRENT_OBJCG_UPDATE_FLAG); + if (old) + obj_cgroup_put(old); + + old = NULL; + } + + /* If new objcg is NULL, no reason for the second atomic update. */ + if (!current->mm || (current->flags & PF_KTHREAD)) + return NULL; + + /* + * Release the objcg pointer from the previous iteration, + * if try_cmpxcg() below fails. + */ + if (unlikely(objcg)) { + obj_cgroup_put(objcg); + objcg = NULL; + } + + /* + * Obtain the new objcg pointer. The current task can be + * asynchronously moved to another memcg and the previous + * memcg can be offlined. So let's get the memcg pointer + * and try get a reference to objcg under a rcu read lock. + */ + + rcu_read_lock(); + memcg = mem_cgroup_from_task(current); + objcg = __get_obj_cgroup_from_memcg(memcg); + rcu_read_unlock(); + + /* + * Try set up a new objcg pointer atomically. If it + * fails, it means the update flag was set concurrently, so + * the whole procedure should be repeated. + */ + } while (!try_cmpxchg(¤t->objcg, &old, objcg)); + + return objcg; +} + __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void) { struct mem_cgroup *memcg; @@ -3090,19 +3145,26 @@ __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void) if (in_task()) { memcg = current->active_memcg; + if (unlikely(memcg)) + goto from_memcg; - /* Memcg to charge can't be determined. */ - if (likely(!memcg) && (!current->mm || (current->flags & PF_KTHREAD))) - return NULL; + objcg = READ_ONCE(current->objcg); + if (unlikely((unsigned long)objcg & CURRENT_OBJCG_UPDATE_FLAG)) + objcg = current_objcg_update(); + + if (objcg) { + obj_cgroup_get(objcg); + return objcg; + } } else { memcg = this_cpu_read(int_active_memcg); - if (likely(!memcg)) - return NULL; + if (unlikely(memcg)) + goto from_memcg; } + return NULL; +from_memcg: rcu_read_lock(); - if (!memcg) - memcg = mem_cgroup_from_task(current); objcg = __get_obj_cgroup_from_memcg(memcg); rcu_read_unlock(); return objcg; @@ -6440,6 +6502,7 @@ static void mem_cgroup_move_task(void) mem_cgroup_clear_mc(); } } + #else /* !CONFIG_MMU */ static int mem_cgroup_can_attach(struct cgroup_taskset *tset) { @@ -6453,8 +6516,39 @@ static void mem_cgroup_move_task(void) } #endif +#ifdef CONFIG_MEMCG_KMEM +static void mem_cgroup_fork(struct task_struct *task) +{ + /* + * Set the update flag to cause task->objcg to be initialized lazily + * on the first allocation. It can be done without any synchronization + * because it's always performed on the current task, so does + * current_objcg_update(). + */ + task->objcg = (struct obj_cgroup *)CURRENT_OBJCG_UPDATE_FLAG; +} + +static void mem_cgroup_exit(struct task_struct *task) +{ + struct obj_cgroup *objcg = task->objcg; + + objcg = (struct obj_cgroup *) + ((unsigned long)objcg & ~CURRENT_OBJCG_UPDATE_FLAG); + if (objcg) + obj_cgroup_put(objcg); + + /* + * Some kernel allocations can happen after this point, + * but let's ignore them. It can be done without any synchronization + * because it's always performed on the current task, so does + * current_objcg_update(). + */ + task->objcg = NULL; +} +#endif + #ifdef CONFIG_LRU_GEN -static void mem_cgroup_attach(struct cgroup_taskset *tset) +static void mem_cgroup_lru_gen_attach(struct cgroup_taskset *tset) { struct task_struct *task; struct cgroup_subsys_state *css; @@ -6472,10 +6566,31 @@ static void mem_cgroup_attach(struct cgroup_taskset *tset) task_unlock(task); } #else +static void mem_cgroup_lru_gen_attach(struct cgroup_taskset *tset) {} +#endif /* CONFIG_LRU_GEN */ + +#ifdef CONFIG_MEMCG_KMEM +static void mem_cgroup_kmem_attach(struct cgroup_taskset *tset) +{ + struct task_struct *task; + struct cgroup_subsys_state *css; + + cgroup_taskset_for_each(task, css, tset) { + /* atomically set the update bit */ + set_bit(CURRENT_OBJCG_UPDATE_BIT, (unsigned long *)&task->objcg); + } +} +#else +static void mem_cgroup_kmem_attach(struct cgroup_taskset *tset) {} +#endif /* CONFIG_MEMCG_KMEM */ + +#if defined(CONFIG_LRU_GEN) || defined(CONFIG_MEMCG_KMEM) static void mem_cgroup_attach(struct cgroup_taskset *tset) { + mem_cgroup_lru_gen_attach(tset); + mem_cgroup_kmem_attach(tset); } -#endif /* CONFIG_LRU_GEN */ +#endif static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value) { @@ -6885,9 +7000,15 @@ struct cgroup_subsys memory_cgrp_subsys = { .css_reset = mem_cgroup_css_reset, .css_rstat_flush = mem_cgroup_css_rstat_flush, .can_attach = mem_cgroup_can_attach, +#if defined(CONFIG_LRU_GEN) || defined(CONFIG_MEMCG_KMEM) .attach = mem_cgroup_attach, +#endif .cancel_attach = mem_cgroup_cancel_attach, .post_attach = mem_cgroup_move_task, +#ifdef CONFIG_MEMCG_KMEM + .fork = mem_cgroup_fork, + .exit = mem_cgroup_exit, +#endif .dfl_cftypes = memory_files, .legacy_cftypes = mem_cgroup_legacy_files, .early_init = 0, -- cgit v1.2.3 From 675d6c9b59e313ca2573c93e8fd87011a99bb8ce Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 19 Oct 2023 15:53:43 -0700 Subject: mm: kmem: make memcg keep a reference to the original objcg Keep a reference to the original objcg object for the entire life of a memcg structure. This allows to simplify the synchronization on the kernel memory allocation paths: pinning a (live) memcg will also pin the corresponding objcg. The memory overhead of this change is minimal because object cgroups usually outlive their corresponding memory cgroups even without this change, so it's only an additional pointer per memcg. Link: https://lkml.kernel.org/r/20231019225346.1822282-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin (Cruise) Tested-by: Naresh Kamboju Acked-by: Shakeel Butt Reviewed-by: Vlastimil Babka Cc: David Rientjes Cc: Dennis Zhou Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 8 +++++++- mm/memcontrol.c | 5 +++++ 2 files changed, 12 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 6674c12725d5..cc110cc8fdfc 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -289,7 +289,13 @@ struct mem_cgroup { #ifdef CONFIG_MEMCG_KMEM int kmemcg_id; - struct obj_cgroup __rcu *objcg; + /* + * memcg->objcg is wiped out as a part of the objcg repaprenting + * process. memcg->orig_objcg preserves a pointer (and a reference) + * to the original objcg until the end of live of memcg. + */ + struct obj_cgroup __rcu *objcg; + struct obj_cgroup *orig_objcg; /* list of inherited objcgs, protected by objcg_lock */ struct list_head objcg_list; #endif diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 96f4c319f025..ff036d5d339d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3899,6 +3899,8 @@ static int memcg_online_kmem(struct mem_cgroup *memcg) objcg->memcg = memcg; rcu_assign_pointer(memcg->objcg, objcg); + obj_cgroup_get(objcg); + memcg->orig_objcg = objcg; static_branch_enable(&memcg_kmem_online_key); @@ -5406,6 +5408,9 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) { int node; + if (memcg->orig_objcg) + obj_cgroup_put(memcg->orig_objcg); + for_each_node(node) free_mem_cgroup_per_node_info(memcg, node); kfree(memcg->vmstats); -- cgit v1.2.3 From e86828e5446d95676835679837d995dec188d2be Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 19 Oct 2023 15:53:44 -0700 Subject: mm: kmem: scoped objcg protection Switch to a scope-based protection of the objcg pointer on slab/kmem allocation paths. Instead of using the get_() semantics in the pre-allocation hook and put the reference afterwards, let's rely on the fact that objcg is pinned by the scope. It's possible because: 1) if the objcg is received from the current task struct, the task is keeping a reference to the objcg. 2) if the objcg is received from an active memcg (remote charging), the memcg is pinned by the scope and has a reference to the corresponding objcg. Link: https://lkml.kernel.org/r/20231019225346.1822282-5-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin (Cruise) Tested-by: Naresh Kamboju Acked-by: Shakeel Butt Reviewed-by: Vlastimil Babka Cc: David Rientjes Cc: Dennis Zhou Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 9 +++++++++ include/linux/sched/mm.h | 4 ++++ mm/memcontrol.c | 47 ++++++++++++++++++++++++++++++++++++++++++++-- mm/slab.h | 15 ++++++++------- 4 files changed, 66 insertions(+), 9 deletions(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index cc110cc8fdfc..8006bc3bd7bf 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1796,6 +1796,15 @@ bool mem_cgroup_kmem_disabled(void); int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order); void __memcg_kmem_uncharge_page(struct page *page, int order); +/* + * The returned objcg pointer is safe to use without additional + * protection within a scope. The scope is defined either by + * the current task (similar to the "current" global variable) + * or by set_active_memcg() pair. + * Please, use obj_cgroup_get() to get a reference if the pointer + * needs to be used outside of the local scope. + */ +struct obj_cgroup *current_obj_cgroup(void); struct obj_cgroup *get_obj_cgroup_from_current(void); struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio); diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 8d89c8c4fac1..9a19f1b42f64 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -403,6 +403,10 @@ DECLARE_PER_CPU(struct mem_cgroup *, int_active_memcg); * __GFP_ACCOUNT allocations till the end of the scope will be charged to the * given memcg. * + * Please, make sure that caller has a reference to the passed memcg structure, + * so its lifetime is guaranteed to exceed the scope between two + * set_active_memcg() calls. + * * NOTE: This function can nest. Users must save the return value and * reset the previous value after their own charging scope is over. */ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ff036d5d339d..a6457c8b5e16 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3170,6 +3170,49 @@ from_memcg: return objcg; } +__always_inline struct obj_cgroup *current_obj_cgroup(void) +{ + struct mem_cgroup *memcg; + struct obj_cgroup *objcg; + + if (in_task()) { + memcg = current->active_memcg; + if (unlikely(memcg)) + goto from_memcg; + + objcg = READ_ONCE(current->objcg); + if (unlikely((unsigned long)objcg & CURRENT_OBJCG_UPDATE_FLAG)) + objcg = current_objcg_update(); + /* + * Objcg reference is kept by the task, so it's safe + * to use the objcg by the current task. + */ + return objcg; + } + + memcg = this_cpu_read(int_active_memcg); + if (unlikely(memcg)) + goto from_memcg; + + return NULL; + +from_memcg: + for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) { + /* + * Memcg pointer is protected by scope (see set_active_memcg()) + * and is pinning the corresponding objcg, so objcg can't go + * away and can be used within the scope without any additional + * protection. + */ + objcg = rcu_dereference_check(memcg->objcg, 1); + if (likely(objcg)) + break; + objcg = NULL; + } + + return objcg; +} + struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio) { struct obj_cgroup *objcg; @@ -3264,15 +3307,15 @@ int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order) struct obj_cgroup *objcg; int ret = 0; - objcg = get_obj_cgroup_from_current(); + objcg = current_obj_cgroup(); if (objcg) { ret = obj_cgroup_charge_pages(objcg, gfp, 1 << order); if (!ret) { + obj_cgroup_get(objcg); page->memcg_data = (unsigned long)objcg | MEMCG_DATA_KMEM; return 0; } - obj_cgroup_put(objcg); } return ret; } diff --git a/mm/slab.h b/mm/slab.h index 799a315695c6..3d07fb428393 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -484,7 +484,12 @@ static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s, if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT)) return true; - objcg = get_obj_cgroup_from_current(); + /* + * The obtained objcg pointer is safe to use within the current scope, + * defined by current task or set_active_memcg() pair. + * obj_cgroup_get() is used to get a permanent reference. + */ + objcg = current_obj_cgroup(); if (!objcg) return true; @@ -497,17 +502,14 @@ static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s, css_put(&memcg->css); if (ret) - goto out; + return false; } if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) - goto out; + return false; *objcgp = objcg; return true; -out: - obj_cgroup_put(objcg); - return false; } static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s, @@ -542,7 +544,6 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s, obj_cgroup_uncharge(objcg, obj_full_size(s)); } } - obj_cgroup_put(objcg); } static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, -- cgit v1.2.3 From e56808fef8f71a192b2740c0b6ea8be7ab865d54 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 19 Oct 2023 15:53:46 -0700 Subject: mm: kmem: reimplement get_obj_cgroup_from_current() Reimplement get_obj_cgroup_from_current() using current_obj_cgroup(). get_obj_cgroup_from_current() and current_obj_cgroup() share 80% of the code, so the new implementation is almost trivial. get_obj_cgroup_from_current() is a convenient function used by the bpf subsystem, so there is no reason to get rid of it completely. Link: https://lkml.kernel.org/r/20231019225346.1822282-7-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin (Cruise) Reviewed-by: Vlastimil Babka Acked-by: Shakeel Butt Cc: David Rientjes Cc: Dennis Zhou Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Cc: Naresh Kamboju Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 11 ++++++++++- mm/memcontrol.c | 32 -------------------------------- 2 files changed, 10 insertions(+), 33 deletions(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 8006bc3bd7bf..b3d2e3e60eed 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1805,9 +1805,18 @@ void __memcg_kmem_uncharge_page(struct page *page, int order); * needs to be used outside of the local scope. */ struct obj_cgroup *current_obj_cgroup(void); -struct obj_cgroup *get_obj_cgroup_from_current(void); struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio); +static inline struct obj_cgroup *get_obj_cgroup_from_current(void) +{ + struct obj_cgroup *objcg = current_obj_cgroup(); + + if (objcg) + obj_cgroup_get(objcg); + + return objcg; +} + int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size); void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a6457c8b5e16..8b0859b8cc03 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3138,38 +3138,6 @@ static struct obj_cgroup *current_objcg_update(void) return objcg; } -__always_inline struct obj_cgroup *get_obj_cgroup_from_current(void) -{ - struct mem_cgroup *memcg; - struct obj_cgroup *objcg; - - if (in_task()) { - memcg = current->active_memcg; - if (unlikely(memcg)) - goto from_memcg; - - objcg = READ_ONCE(current->objcg); - if (unlikely((unsigned long)objcg & CURRENT_OBJCG_UPDATE_FLAG)) - objcg = current_objcg_update(); - - if (objcg) { - obj_cgroup_get(objcg); - return objcg; - } - } else { - memcg = this_cpu_read(int_active_memcg); - if (unlikely(memcg)) - goto from_memcg; - } - return NULL; - -from_memcg: - rcu_read_lock(); - objcg = __get_obj_cgroup_from_memcg(memcg); - rcu_read_unlock(); - return objcg; -} - __always_inline struct obj_cgroup *current_obj_cgroup(void) { struct mem_cgroup *memcg; -- cgit v1.2.3 From 1d44f2e6d178163a94980fd5f9a4b04b6b36535b Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 18 Oct 2023 22:07:48 +0800 Subject: mm_types: add virtual and _last_cpupid into struct folio Patch series "mm: convert page cpupid functions to folios", v3. The cpupid(or access time) used by numa balancing is stored in flags or _last_cpupid(if LAST_CPUPID_NOT_IN_PAGE_FLAGS) of page, this is to convert page cpupid to folio cpupid, a new _last_cpupid is added into folio, which make us to use folio->_last_cpupid directly, and the page cpupid functions are converted to folio ones. page_cpupid_last() -> folio_last_cpupid() xchg_page_access_time() -> folio_xchg_access_time() page_cpupid_xchg_last() -> folio_xchg_last_cpupid() This patch (of 19): If WANT_PAGE_VIRTUAL and LAST_CPUPID_NOT_IN_PAGE_FLAGS defined, the 'virtual' and '_last_cpupid' are in struct page, and since _last_cpupid is used by numa balancing feature, it is better to move it before KMSAN metadata from struct page, also add them into struct folio to make us to access them from folio directly. Link: https://lkml.kernel.org/r/20231018140806.2783514-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20231018140806.2783514-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Huang Ying Cc: Ingo Molnar Cc: Juri Lelli Cc: Matthew Wilcox (Oracle) Cc: Peter Zijlstra Cc: Vincent Guittot Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mm_types.h | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 21eb56145f57..692e41213cd3 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -199,6 +199,10 @@ struct page { not kmapped, ie. highmem) */ #endif /* WANT_PAGE_VIRTUAL */ +#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS + int _last_cpupid; +#endif + #ifdef CONFIG_KMSAN /* * KMSAN metadata for this page: @@ -210,10 +214,6 @@ struct page { struct page *kmsan_shadow; struct page *kmsan_origin; #endif - -#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS - int _last_cpupid; -#endif } _struct_page_alignment; /* @@ -272,6 +272,8 @@ typedef struct { * @_refcount: Do not access this member directly. Use folio_ref_count() * to find how many references there are to this folio. * @memcg_data: Memory Control Group data. + * @virtual: Virtual address in the kernel direct map. + * @_last_cpupid: IDs of last CPU and last process that accessed the folio. * @_entire_mapcount: Do not use directly, call folio_entire_mapcount(). * @_nr_pages_mapped: Do not use directly, call folio_mapcount(). * @_pincount: Do not use directly, call folio_maybe_dma_pinned(). @@ -317,6 +319,12 @@ struct folio { atomic_t _refcount; #ifdef CONFIG_MEMCG unsigned long memcg_data; +#endif +#if defined(WANT_PAGE_VIRTUAL) + void *virtual; +#endif +#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS + int _last_cpupid; #endif /* private: the union with struct page is transitional */ }; @@ -373,6 +381,12 @@ FOLIO_MATCH(_refcount, _refcount); #ifdef CONFIG_MEMCG FOLIO_MATCH(memcg_data, memcg_data); #endif +#if defined(WANT_PAGE_VIRTUAL) +FOLIO_MATCH(virtual, virtual); +#endif +#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS +FOLIO_MATCH(_last_cpupid, _last_cpupid); +#endif #undef FOLIO_MATCH #define FOLIO_MATCH(pg, fl) \ static_assert(offsetof(struct folio, fl) == \ -- cgit v1.2.3 From 155c98cfcf961327adedabd629edfc2301cf354b Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 18 Oct 2023 22:07:49 +0800 Subject: mm: add folio_last_cpupid() Add folio_last_cpupid() wrapper, which is required to convert page_cpupid_last() to folio vertion later in the series. Link: https://lkml.kernel.org/r/20231018140806.2783514-3-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Huang Ying Cc: Ingo Molnar Cc: Juri Lelli Cc: Matthew Wilcox (Oracle) Cc: Peter Zijlstra Cc: Vincent Guittot Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mm.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 86e040e886e4..0c4ff852930b 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1796,6 +1796,11 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma) } #endif /* CONFIG_NUMA_BALANCING */ +static inline int folio_last_cpupid(struct folio *folio) +{ + return page_cpupid_last(&folio->page); +} + #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) /* -- cgit v1.2.3 From f39eac30a8f334f0765ef78fe4d13b3fd5bfa3fd Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 18 Oct 2023 22:07:53 +0800 Subject: mm: remove page_cpupid_last() Since all calls use folio_last_cpupid(), remove page_cpupid_last(). Link: https://lkml.kernel.org/r/20231018140806.2783514-7-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Huang Ying Cc: Ingo Molnar Cc: Juri Lelli Cc: Matthew Wilcox (Oracle) Cc: Peter Zijlstra Cc: Vincent Guittot Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mm.h | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 0c4ff852930b..f8b7a1825720 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1702,18 +1702,18 @@ static inline int page_cpupid_xchg_last(struct page *page, int cpupid) return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK); } -static inline int page_cpupid_last(struct page *page) +static inline int folio_last_cpupid(struct folio *folio) { - return page->_last_cpupid; + return folio->_last_cpupid; } static inline void page_cpupid_reset_last(struct page *page) { page->_last_cpupid = -1 & LAST_CPUPID_MASK; } #else -static inline int page_cpupid_last(struct page *page) +static inline int folio_last_cpupid(struct folio *folio) { - return (page->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK; + return (folio->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK; } extern int page_cpupid_xchg_last(struct page *page, int cpupid); @@ -1752,9 +1752,9 @@ static inline int xchg_page_access_time(struct page *page, int time) return 0; } -static inline int page_cpupid_last(struct page *page) +static inline int folio_last_cpupid(struct folio *folio) { - return page_to_nid(page); /* XXX */ + return folio_nid(folio); /* XXX */ } static inline int cpupid_to_nid(int cpupid) @@ -1796,11 +1796,6 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma) } #endif /* CONFIG_NUMA_BALANCING */ -static inline int folio_last_cpupid(struct folio *folio) -{ - return page_cpupid_last(&folio->page); -} - #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) /* -- cgit v1.2.3 From 55c199385c4465e9abe1a3d6d1aba348d0356e03 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 18 Oct 2023 22:07:54 +0800 Subject: mm: add folio_xchg_access_time() Add folio_xchg_access_time() wrapper, which is required to convert xchg_page_access_time() to folio vertion later in the series. Link: https://lkml.kernel.org/r/20231018140806.2783514-8-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Huang Ying Cc: Ingo Molnar Cc: Juri Lelli Cc: Matthew Wilcox (Oracle) Cc: Peter Zijlstra Cc: Vincent Guittot Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mm.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index f8b7a1825720..dee63b820f0c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1796,6 +1796,11 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma) } #endif /* CONFIG_NUMA_BALANCING */ +static inline int folio_xchg_access_time(struct folio *folio, int time) +{ + return xchg_page_access_time(&folio->page, time); +} + #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) /* -- cgit v1.2.3 From f393084382fa3bbd5840b428d538dbcb33be0186 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 18 Oct 2023 22:07:58 +0800 Subject: mm: remove xchg_page_access_time() Since all calls use folio_xchg_access_time(), remove xchg_page_access_time(). Link: https://lkml.kernel.org/r/20231018140806.2783514-12-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Huang Ying Cc: Ingo Molnar Cc: Juri Lelli Cc: Matthew Wilcox (Oracle) Cc: Peter Zijlstra Cc: Vincent Guittot Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mm.h | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index dee63b820f0c..e003465238c4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1724,11 +1724,12 @@ static inline void page_cpupid_reset_last(struct page *page) } #endif /* LAST_CPUPID_NOT_IN_PAGE_FLAGS */ -static inline int xchg_page_access_time(struct page *page, int time) +static inline int folio_xchg_access_time(struct folio *folio, int time) { int last_time; - last_time = page_cpupid_xchg_last(page, time >> PAGE_ACCESS_TIME_BUCKETS); + last_time = page_cpupid_xchg_last(&folio->page, + time >> PAGE_ACCESS_TIME_BUCKETS); return last_time << PAGE_ACCESS_TIME_BUCKETS; } @@ -1747,7 +1748,7 @@ static inline int page_cpupid_xchg_last(struct page *page, int cpupid) return page_to_nid(page); /* XXX */ } -static inline int xchg_page_access_time(struct page *page, int time) +static inline int folio_xchg_access_time(struct folio *folio, int time) { return 0; } @@ -1796,11 +1797,6 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma) } #endif /* CONFIG_NUMA_BALANCING */ -static inline int folio_xchg_access_time(struct folio *folio, int time) -{ - return xchg_page_access_time(&folio->page, time); -} - #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) /* -- cgit v1.2.3 From 136d0b47576f8701d68c2d504e7237d9fdc4ebbd Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 18 Oct 2023 22:07:59 +0800 Subject: mm: add folio_xchg_last_cpupid() Add folio_xchg_last_cpupid() wrapper, which is required to convert page_cpupid_xchg_last() to folio vertion later in the series. Link: https://lkml.kernel.org/r/20231018140806.2783514-13-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Huang Ying Cc: Ingo Molnar Cc: Juri Lelli Cc: Matthew Wilcox (Oracle) Cc: Peter Zijlstra Cc: Vincent Guittot Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mm.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index e003465238c4..00e0874f7ce2 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1797,6 +1797,11 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma) } #endif /* CONFIG_NUMA_BALANCING */ +static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid) +{ + return page_cpupid_xchg_last(&folio->page, cpupid); +} + #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) /* -- cgit v1.2.3 From c08b7e3830dbf24dd2552ddeea84f00393842f1b Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 18 Oct 2023 22:08:03 +0800 Subject: mm: make finish_mkwrite_fault() static Make finish_mkwrite_fault static since it is not used outside of memory.c. Link: https://lkml.kernel.org/r/20231018140806.2783514-17-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Huang Ying Cc: Ingo Molnar Cc: Juri Lelli Cc: Matthew Wilcox (Oracle) Cc: Peter Zijlstra Cc: Vincent Guittot Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mm.h | 1 - mm/memory.c | 2 +- 2 files changed, 1 insertion(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 00e0874f7ce2..5d6e1d7656c2 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1348,7 +1348,6 @@ void set_pte_range(struct vm_fault *vmf, struct folio *folio, struct page *page, unsigned int nr, unsigned long addr); vm_fault_t finish_fault(struct vm_fault *vmf); -vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf); #endif /* diff --git a/mm/memory.c b/mm/memory.c index 0915eac772fe..2b6e2b239411 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3269,7 +3269,7 @@ out: * Return: %0 on success, %VM_FAULT_NOPAGE when PTE got changed before * we acquired PTE lock. */ -vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) +static vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) { WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED)); vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, -- cgit v1.2.3 From 8f0f4788b1247c2f92ecacd8f86ce0b379b807b9 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 18 Oct 2023 22:08:06 +0800 Subject: mm: remove page_cpupid_xchg_last() Since all calls use folio_xchg_last_cpupid(), remove page_cpupid_xchg_last(). Link: https://lkml.kernel.org/r/20231018140806.2783514-20-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Huang Ying Cc: Ingo Molnar Cc: Juri Lelli Cc: Matthew Wilcox (Oracle) Cc: Peter Zijlstra Cc: Vincent Guittot Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/mm.h | 19 +++++++------------ mm/mmzone.c | 6 +++--- 2 files changed, 10 insertions(+), 15 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 5d6e1d7656c2..0e496a8b8e50 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1696,9 +1696,9 @@ static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid) #define cpupid_match_pid(task, cpupid) __cpupid_match_pid(task->pid, cpupid) #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS -static inline int page_cpupid_xchg_last(struct page *page, int cpupid) +static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid) { - return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK); + return xchg(&folio->_last_cpupid, cpupid & LAST_CPUPID_MASK); } static inline int folio_last_cpupid(struct folio *folio) @@ -1715,7 +1715,7 @@ static inline int folio_last_cpupid(struct folio *folio) return (folio->flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK; } -extern int page_cpupid_xchg_last(struct page *page, int cpupid); +int folio_xchg_last_cpupid(struct folio *folio, int cpupid); static inline void page_cpupid_reset_last(struct page *page) { @@ -1727,8 +1727,8 @@ static inline int folio_xchg_access_time(struct folio *folio, int time) { int last_time; - last_time = page_cpupid_xchg_last(&folio->page, - time >> PAGE_ACCESS_TIME_BUCKETS); + last_time = folio_xchg_last_cpupid(folio, + time >> PAGE_ACCESS_TIME_BUCKETS); return last_time << PAGE_ACCESS_TIME_BUCKETS; } @@ -1742,9 +1742,9 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma) } } #else /* !CONFIG_NUMA_BALANCING */ -static inline int page_cpupid_xchg_last(struct page *page, int cpupid) +static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid) { - return page_to_nid(page); /* XXX */ + return folio_nid(folio); /* XXX */ } static inline int folio_xchg_access_time(struct folio *folio, int time) @@ -1796,11 +1796,6 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma) } #endif /* CONFIG_NUMA_BALANCING */ -static inline int folio_xchg_last_cpupid(struct folio *folio, int cpupid) -{ - return page_cpupid_xchg_last(&folio->page, cpupid); -} - #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) /* diff --git a/mm/mmzone.c b/mm/mmzone.c index 68e1511be12d..b594d3f268fe 100644 --- a/mm/mmzone.c +++ b/mm/mmzone.c @@ -93,19 +93,19 @@ void lruvec_init(struct lruvec *lruvec) } #if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) -int page_cpupid_xchg_last(struct page *page, int cpupid) +int folio_xchg_last_cpupid(struct folio *folio, int cpupid) { unsigned long old_flags, flags; int last_cpupid; - old_flags = READ_ONCE(page->flags); + old_flags = READ_ONCE(folio->flags); do { flags = old_flags; last_cpupid = (flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK; flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT); flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT; - } while (unlikely(!try_cmpxchg(&page->flags, &old_flags, flags))); + } while (unlikely(!try_cmpxchg(&folio->flags, &old_flags, flags))); return last_cpupid; } -- cgit v1.2.3 From 80203f1ca086835100843f1474bd6dd4a48cc73b Mon Sep 17 00:00:00 2001 From: Liu Shixin Date: Wed, 18 Oct 2023 18:29:47 +0800 Subject: bootmem: use kmemleak_free_part_phys in free_bootmem_page Since kmemleak_alloc_phys() rather than kmemleak_alloc() was called from memblock_alloc_range_nid(), kmemleak_free_part_phys() should be used to delete kmemleak object in free_bootmem_page(). In debug mode, there are following warning: kmemleak: Partially freeing unknown object at 0xffff97345aff7000 (size 4096) Link: https://lkml.kernel.org/r/20231018102952.3339837-3-liushixin2@huawei.com Fixes: 028725e73375 ("bootmem: remove the vmemmap pages from kmemleak in free_bootmem_page") Signed-off-by: Liu Shixin Acked-by: Catalin Marinas Cc: Kefeng Wang Cc: Patrick Wang Signed-off-by: Andrew Morton --- include/linux/bootmem_info.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/bootmem_info.h b/include/linux/bootmem_info.h index e1a3c9c9754c..cffa38a73618 100644 --- a/include/linux/bootmem_info.h +++ b/include/linux/bootmem_info.h @@ -60,7 +60,7 @@ static inline void get_page_bootmem(unsigned long info, struct page *page, static inline void free_bootmem_page(struct page *page) { - kmemleak_free_part(page_to_virt(page), PAGE_SIZE); + kmemleak_free_part_phys(PFN_PHYS(page_to_pfn(page)), PAGE_SIZE); free_reserved_page(page); } #endif -- cgit v1.2.3 From b455f39d228935f88eebcd1f7c1a6981093c6a3b Mon Sep 17 00:00:00 2001 From: "Vishal Moola (Oracle)" Date: Fri, 20 Oct 2023 11:33:30 -0700 Subject: mm/khugepaged: convert alloc_charge_hpage() to use folios Also remove count_memcg_page_event now that its last caller no longer uses it and reword hpage_collapse_alloc_page() to hpage_collapse_alloc_folio(). This removes 1 call to compound_head() and helps convert khugepaged to use folios throughout. Link: https://lkml.kernel.org/r/20231020183331.10770-5-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Reviewed-by: Rik van Riel Reviewed-by: Yang Shi Cc: Kefeng Wang Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 14 -------------- mm/khugepaged.c | 17 ++++++++++------- 2 files changed, 10 insertions(+), 21 deletions(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index b3d2e3e60eed..7bdcf3020d7a 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1087,15 +1087,6 @@ static inline void count_memcg_events(struct mem_cgroup *memcg, local_irq_restore(flags); } -static inline void count_memcg_page_event(struct page *page, - enum vm_event_item idx) -{ - struct mem_cgroup *memcg = page_memcg(page); - - if (memcg) - count_memcg_events(memcg, idx, 1); -} - static inline void count_memcg_folio_events(struct folio *folio, enum vm_event_item idx, unsigned long nr) { @@ -1598,11 +1589,6 @@ static inline void __count_memcg_events(struct mem_cgroup *memcg, { } -static inline void count_memcg_page_event(struct page *page, - int idx) -{ -} - static inline void count_memcg_folio_events(struct folio *folio, enum vm_event_item idx, unsigned long nr) { diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 9efd8ff68f06..6a7184cd291b 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -888,16 +888,16 @@ static int hpage_collapse_find_target_node(struct collapse_control *cc) } #endif -static bool hpage_collapse_alloc_page(struct page **hpage, gfp_t gfp, int node, +static bool hpage_collapse_alloc_folio(struct folio **folio, gfp_t gfp, int node, nodemask_t *nmask) { - *hpage = __alloc_pages(gfp, HPAGE_PMD_ORDER, node, nmask); - if (unlikely(!*hpage)) { + *folio = __folio_alloc(gfp, HPAGE_PMD_ORDER, node, nmask); + + if (unlikely(!*folio)) { count_vm_event(THP_COLLAPSE_ALLOC_FAILED); return false; } - folio_prep_large_rmappable((struct folio *)*hpage); count_vm_event(THP_COLLAPSE_ALLOC); return true; } @@ -1064,17 +1064,20 @@ static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm, int node = hpage_collapse_find_target_node(cc); struct folio *folio; - if (!hpage_collapse_alloc_page(hpage, gfp, node, &cc->alloc_nmask)) + if (!hpage_collapse_alloc_folio(&folio, gfp, node, &cc->alloc_nmask)) { + *hpage = NULL; return SCAN_ALLOC_HUGE_PAGE_FAIL; + } - folio = page_folio(*hpage); if (unlikely(mem_cgroup_charge(folio, mm, gfp))) { folio_put(folio); *hpage = NULL; return SCAN_CGROUP_CHARGE_FAIL; } - count_memcg_page_event(*hpage, THP_COLLAPSE_ALLOC); + count_memcg_folio_events(folio, THP_COLLAPSE_ALLOC, 1); + + *hpage = folio_page(folio, 0); return SCAN_SUCCEED; } -- cgit v1.2.3 From 35f5d94187a6a3a8df2cba54beccca1c2379edb8 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Thu, 19 Oct 2023 19:49:20 +0000 Subject: mm/damon: implement a function for max nr_accesses safe calculation Patch series "avoid divide-by-zero due to max_nr_accesses overflow". The maximum nr_accesses of given DAMON context can be calculated by dividing the aggregation interval by the sampling interval. Some logics in DAMON uses the maximum nr_accesses as a divisor. Hence, the value shouldn't be zero. Such case is avoided since DAMON avoids setting the agregation interval as samller than the sampling interval. However, since nr_accesses is unsigned int while the intervals are unsigned long, the maximum nr_accesses could be zero while casting. Avoid the divide-by-zero by implementing a function that handles the corner case (first patch), and replaces the vulnerable direct max nr_accesses calculations (remaining patches). Note that the patches for the replacements are divided for broken commits, to make backporting on required tres easier. Especially, the last patch is for a patch that not yet merged into the mainline but in mm tree. This patch (of 4): The maximum nr_accesses of given DAMON context can be calculated by dividing the aggregation interval by the sampling interval. Some logics in DAMON uses the maximum nr_accesses as a divisor. Hence, the value shouldn't be zero. Such case is avoided since DAMON avoids setting the agregation interval as samller than the sampling interval. However, since nr_accesses is unsigned int while the intervals are unsigned long, the maximum nr_accesses could be zero while casting. Implement a function that handles the corner case. Note that this commit is not fixing the real issue since this is only introducing the safe function that will replaces the problematic divisions. The replacements will be made by followup commits, to make backporting on stable series easier. Link: https://lkml.kernel.org/r/20231019194924.100347-1-sj@kernel.org Link: https://lkml.kernel.org/r/20231019194924.100347-2-sj@kernel.org Fixes: 198f0f4c58b9 ("mm/damon/vaddr,paddr: support pageout prioritization") Signed-off-by: SeongJae Park Reported-by: Jakub Acs Cc: [5.16+] Signed-off-by: Andrew Morton --- include/linux/damon.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux') diff --git a/include/linux/damon.h b/include/linux/damon.h index 27b995c22497..ab2f17d9926b 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -681,6 +681,13 @@ static inline bool damon_target_has_pid(const struct damon_ctx *ctx) return ctx->ops.id == DAMON_OPS_VADDR || ctx->ops.id == DAMON_OPS_FVADDR; } +static inline unsigned int damon_max_nr_accesses(const struct damon_attrs *attrs) +{ + /* {aggr,sample}_interval are unsigned long, hence could overflow */ + return min(attrs->aggr_interval / attrs->sample_interval, + (unsigned long)UINT_MAX); +} + int damon_start(struct damon_ctx **ctxs, int nr_ctxs, bool exclusive); int damon_stop(struct damon_ctx **ctxs, int nr_ctxs); -- cgit v1.2.3 From 10969b5571387047cd461a9c701b8b9cd007f6c7 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 3 Oct 2023 02:15:09 -0700 Subject: hugetlbfs: drop shared NUMA mempolicy pretence Patch series "mempolicy: cleanups leading to NUMA mpol without vma", v2. Mostly cleanups in mm/mempolicy.c, but finally removing the pseudo-vma from shmem folio allocation, and removing the mmap_lock around folio migration for mbind and migrate_pages syscalls. This patch (of 12): hugetlbfs_fallocate() goes through the motions of pasting a shared NUMA mempolicy onto its pseudo-vma, but how could there ever be a shared NUMA mempolicy for this file? hugetlb_vm_ops has never offered a set_policy method, and hugetlbfs_parse_param() has never supported any mpol options for a mount-wide default policy. It's just an illusion: clean it away so as not to confuse others, giving us more freedom to adjust shmem's set_policy/get_policy implementation. But hugetlbfs_inode_info is still required, just to accommodate seals. Yes, shared NUMA mempolicy support could be added to hugetlbfs, with a set_policy method and/or mpol mount option (Andi's first posting did include an admitted-unsatisfactory hugetlb_set_policy()); but it seems that nobody has bothered to add that in the nineteen years since v2.6.7 made it possible, and there is at least one company that has invested enough into hugetlbfs, that I guess they have learnt well enough how to manage its NUMA, without needing shared mempolicy. Remove linux/mempolicy.h from linux/hugetlb.h: include linux/pagemap.h in its place, because hugetlb.h's recently added use of filemap_lock_folio() requires that (although most .configs and .c's get it in some other way). Link: https://lkml.kernel.org/r/ebc0987e-beff-8bfb-9283-234c2cbd17c5@google.com Link: https://lkml.kernel.org/r/cae82d4b-904a-faaf-282a-34fcc188c81f@google.com Signed-off-by: Hugh Dickins Reviewed-by: Matthew Wilcox (Oracle) Cc: Andi Kleen Cc: Christoph Lameter Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "Huang, Ying" Cc: Kefeng Wang Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Kravetz Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Tejun heo Cc: Vishal Moola (Oracle) Cc: Yang Shi Cc: Nhat Pham Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- fs/hugetlbfs/inode.c | 41 +---------------------------------------- include/linux/hugetlb.h | 3 +-- 2 files changed, 2 insertions(+), 42 deletions(-) (limited to 'include/linux') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 85cd418d2340..3ad5fc3cb8db 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -83,29 +83,6 @@ static const struct fs_parameter_spec hugetlb_fs_parameters[] = { {} }; -#ifdef CONFIG_NUMA -static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma, - struct inode *inode, pgoff_t index) -{ - vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy, - index); -} - -static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma) -{ - mpol_cond_put(vma->vm_policy); -} -#else -static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma, - struct inode *inode, pgoff_t index) -{ -} - -static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma) -{ -} -#endif - /* * Mask used when checking the page offset value passed in via system * calls. This value will be converted to a loff_t which is signed. @@ -853,8 +830,7 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, /* * Initialize a pseudo vma as this is required by the huge page - * allocation routines. If NUMA is configured, use page index - * as input to create an allocation policy. + * allocation routines. */ vma_init(&pseudo_vma, mm); vm_flags_init(&pseudo_vma, VM_HUGETLB | VM_MAYSHARE | VM_SHARED); @@ -902,9 +878,7 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, * folios in these areas, we need to consume the reserves * to keep reservation accounting consistent. */ - hugetlb_set_vma_policy(&pseudo_vma, inode, index); folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0); - hugetlb_drop_vma_policy(&pseudo_vma); if (IS_ERR(folio)) { mutex_unlock(&hugetlb_fault_mutex_table[hash]); error = PTR_ERR(folio); @@ -1283,18 +1257,6 @@ static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) hugetlbfs_inc_free_inodes(sbinfo); return NULL; } - - /* - * Any time after allocation, hugetlbfs_destroy_inode can be called - * for the inode. mpol_free_shared_policy is unconditionally called - * as part of hugetlbfs_destroy_inode. So, initialize policy here - * in case of a quick call to destroy. - * - * Note that the policy is initialized even if we are creating a - * private inode. This simplifies hugetlbfs_destroy_inode. - */ - mpol_shared_policy_init(&p->policy, NULL); - return &p->vfs_inode; } @@ -1306,7 +1268,6 @@ static void hugetlbfs_free_inode(struct inode *inode) static void hugetlbfs_destroy_inode(struct inode *inode) { hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); - mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); } static const struct address_space_operations hugetlbfs_aops = { diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 205469aa0613..158ff156710b 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -30,7 +30,7 @@ void free_huge_folio(struct folio *folio); #ifdef CONFIG_HUGETLB_PAGE -#include +#include #include #include @@ -545,7 +545,6 @@ static inline struct hugetlbfs_sb_info *HUGETLBFS_SB(struct super_block *sb) } struct hugetlbfs_inode_info { - struct shared_policy policy; struct inode vfs_inode; unsigned int seals; }; -- cgit v1.2.3 From c36f6e6dff4d32ec8b6da8f553933727a57a7a4a Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 3 Oct 2023 02:20:14 -0700 Subject: mempolicy trivia: slightly more consistent naming Before getting down to work, do a little cleanup, mainly of inconsistent variable naming. I gave up trying to rationalize mpol versus pol versus policy, and node versus nid, but let's avoid p and nd. Remove a few superfluous blank lines, but add one; and here prefer vma->vm_policy to vma_policy(vma) - the latter being appropriate in other sources, which have to allow for !CONFIG_NUMA. That intriguing line about KERNEL_DS? should have gone in v2.6.15, when numa_policy_init() stopped using set_mempolicy(2)'s system call handler. Link: https://lkml.kernel.org/r/68287974-b6ae-7df-4ba-d19ddd69cbf@google.com Signed-off-by: Hugh Dickins Reviewed-by: Matthew Wilcox (Oracle) Cc: Andi Kleen Cc: Christoph Lameter Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "Huang, Ying" Cc: Kefeng Wang Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Kravetz Cc: Nhat Pham Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Tejun heo Cc: Vishal Moola (Oracle) Cc: Yang Shi Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- include/linux/mempolicy.h | 11 ++++--- mm/mempolicy.c | 73 +++++++++++++++++++++-------------------------- 2 files changed, 38 insertions(+), 46 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index 1d7f4ec2614c..a807976fe95d 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -124,10 +124,9 @@ struct shared_policy { int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst); void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol); -int mpol_set_shared_policy(struct shared_policy *info, - struct vm_area_struct *vma, - struct mempolicy *new); -void mpol_free_shared_policy(struct shared_policy *p); +int mpol_set_shared_policy(struct shared_policy *sp, + struct vm_area_struct *vma, struct mempolicy *mpol); +void mpol_free_shared_policy(struct shared_policy *sp); struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx); @@ -191,7 +190,7 @@ static inline bool mpol_equal(struct mempolicy *a, struct mempolicy *b) return true; } -static inline void mpol_put(struct mempolicy *p) +static inline void mpol_put(struct mempolicy *pol) { } @@ -210,7 +209,7 @@ static inline void mpol_shared_policy_init(struct shared_policy *sp, { } -static inline void mpol_free_shared_policy(struct shared_policy *p) +static inline void mpol_free_shared_policy(struct shared_policy *sp) { } diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 02a9b89c10aa..50a57f4c8013 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -25,7 +25,7 @@ * to the last. It would be better if bind would truly restrict * the allocation to memory nodes instead * - * preferred Try a specific node first before normal fallback. + * preferred Try a specific node first before normal fallback. * As a special case NUMA_NO_NODE here means do the allocation * on the local CPU. This is normally identical to default, * but useful to set in a VMA when you have a non default @@ -52,7 +52,7 @@ * on systems with highmem kernel lowmem allocation don't get policied. * Same with GFP_DMA allocations. * - * For shmfs/tmpfs/hugetlbfs shared memory the policy is shared between + * For shmem/tmpfs shared memory the policy is shared between * all users and remembered even when nobody has memory mapped. */ @@ -291,6 +291,7 @@ static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags, return ERR_PTR(-EINVAL); } else if (nodes_empty(*nodes)) return ERR_PTR(-EINVAL); + policy = kmem_cache_alloc(policy_cache, GFP_KERNEL); if (!policy) return ERR_PTR(-ENOMEM); @@ -303,11 +304,11 @@ static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags, } /* Slow path of a mpol destructor. */ -void __mpol_put(struct mempolicy *p) +void __mpol_put(struct mempolicy *pol) { - if (!atomic_dec_and_test(&p->refcnt)) + if (!atomic_dec_and_test(&pol->refcnt)) return; - kmem_cache_free(policy_cache, p); + kmem_cache_free(policy_cache, pol); } static void mpol_rebind_default(struct mempolicy *pol, const nodemask_t *nodes) @@ -364,7 +365,6 @@ static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask) * * Called with task's alloc_lock held. */ - void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new) { mpol_rebind_policy(tsk->mempolicy, new); @@ -375,7 +375,6 @@ void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new) * * Call holding a reference to mm. Takes mm->mmap_lock during call. */ - void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new) { struct vm_area_struct *vma; @@ -757,7 +756,7 @@ queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end, * This must be called with the mmap_lock held for writing. */ static int vma_replace_policy(struct vm_area_struct *vma, - struct mempolicy *pol) + struct mempolicy *pol) { int err; struct mempolicy *old; @@ -800,7 +799,7 @@ static int mbind_range(struct vma_iterator *vmi, struct vm_area_struct *vma, vmstart = vma->vm_start; } - if (mpol_equal(vma_policy(vma), new_pol)) { + if (mpol_equal(vma->vm_policy, new_pol)) { *prev = vma; return 0; } @@ -855,18 +854,18 @@ out: * * Called with task's alloc_lock held */ -static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes) +static void get_policy_nodemask(struct mempolicy *pol, nodemask_t *nodes) { nodes_clear(*nodes); - if (p == &default_policy) + if (pol == &default_policy) return; - switch (p->mode) { + switch (pol->mode) { case MPOL_BIND: case MPOL_INTERLEAVE: case MPOL_PREFERRED: case MPOL_PREFERRED_MANY: - *nodes = p->nodes; + *nodes = pol->nodes; break; case MPOL_LOCAL: /* return empty node mask for local allocation */ @@ -1634,7 +1633,6 @@ out: out_put: put_task_struct(task); goto out; - } SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode, @@ -1644,7 +1642,6 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode, return kernel_migrate_pages(pid, maxnode, old_nodes, new_nodes); } - /* Retrieve NUMA policy */ static int kernel_get_mempolicy(int __user *policy, unsigned long __user *nmask, @@ -1827,10 +1824,10 @@ nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy) * policy_node() is always coupled with policy_nodemask(), which * secures the nodemask limit for 'bind' and 'prefer-many' policy. */ -static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd) +static int policy_node(gfp_t gfp, struct mempolicy *policy, int nid) { if (policy->mode == MPOL_PREFERRED) { - nd = first_node(policy->nodes); + nid = first_node(policy->nodes); } else { /* * __GFP_THISNODE shouldn't even be used with the bind policy @@ -1845,19 +1842,18 @@ static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd) policy->home_node != NUMA_NO_NODE) return policy->home_node; - return nd; + return nid; } /* Do dynamic interleaving for a process */ -static unsigned interleave_nodes(struct mempolicy *policy) +static unsigned int interleave_nodes(struct mempolicy *policy) { - unsigned next; - struct task_struct *me = current; + unsigned int nid; - next = next_node_in(me->il_prev, policy->nodes); - if (next < MAX_NUMNODES) - me->il_prev = next; - return next; + nid = next_node_in(current->il_prev, policy->nodes); + if (nid < MAX_NUMNODES) + current->il_prev = nid; + return nid; } /* @@ -2347,7 +2343,7 @@ unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp, int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst) { - struct mempolicy *pol = mpol_dup(vma_policy(src)); + struct mempolicy *pol = mpol_dup(src->vm_policy); if (IS_ERR(pol)) return PTR_ERR(pol); @@ -2771,40 +2767,40 @@ put_mpol: } } -int mpol_set_shared_policy(struct shared_policy *info, - struct vm_area_struct *vma, struct mempolicy *npol) +int mpol_set_shared_policy(struct shared_policy *sp, + struct vm_area_struct *vma, struct mempolicy *pol) { int err; struct sp_node *new = NULL; unsigned long sz = vma_pages(vma); - if (npol) { - new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol); + if (pol) { + new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, pol); if (!new) return -ENOMEM; } - err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new); + err = shared_policy_replace(sp, vma->vm_pgoff, vma->vm_pgoff + sz, new); if (err && new) sp_free(new); return err; } /* Free a backing policy store on inode delete. */ -void mpol_free_shared_policy(struct shared_policy *p) +void mpol_free_shared_policy(struct shared_policy *sp) { struct sp_node *n; struct rb_node *next; - if (!p->root.rb_node) + if (!sp->root.rb_node) return; - write_lock(&p->lock); - next = rb_first(&p->root); + write_lock(&sp->lock); + next = rb_first(&sp->root); while (next) { n = rb_entry(next, struct sp_node, nd); next = rb_next(&n->nd); - sp_delete(p, n); + sp_delete(sp, n); } - write_unlock(&p->lock); + write_unlock(&sp->lock); } #ifdef CONFIG_NUMA_BALANCING @@ -2854,7 +2850,6 @@ static inline void __init check_numabalancing_enable(void) } #endif /* CONFIG_NUMA_BALANCING */ -/* assumes fs == KERNEL_DS */ void __init numa_policy_init(void) { nodemask_t interleave_nodes; @@ -2917,7 +2912,6 @@ void numa_default_policy(void) /* * Parse and format mempolicy from/to strings */ - static const char * const policy_modes[] = { [MPOL_DEFAULT] = "default", @@ -2928,7 +2922,6 @@ static const char * const policy_modes[] = [MPOL_PREFERRED_MANY] = "prefer (many)", }; - #ifdef CONFIG_TMPFS /** * mpol_parse_str - parse string to mempolicy, for tmpfs mpol mount option. -- cgit v1.2.3 From 93397c3b7684555b7cec726cd13eef6742d191fe Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 3 Oct 2023 02:21:34 -0700 Subject: mempolicy trivia: use pgoff_t in shared mempolicy tree Prefer the more explicit "pgoff_t" to "unsigned long" when dealing with a shared mempolicy tree. Delete confusing comment about pseudo mm vmas. Link: https://lkml.kernel.org/r/5451157-3818-4af5-fd2c-5d26a5d1dc53@google.com Signed-off-by: Hugh Dickins Cc: Andi Kleen Cc: Christoph Lameter Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "Huang, Ying" Cc: Kefeng Wang Cc: Matthew Wilcox (Oracle) Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Kravetz Cc: Nhat Pham Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Tejun heo Cc: Vishal Moola (Oracle) Cc: Yang Shi Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- include/linux/mempolicy.h | 20 +++++++------------- mm/mempolicy.c | 12 ++++++------ 2 files changed, 13 insertions(+), 19 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index a807976fe95d..acdb12fcb6cd 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -105,22 +105,16 @@ static inline bool mpol_equal(struct mempolicy *a, struct mempolicy *b) /* * Tree of shared policies for a shared memory region. - * Maintain the policies in a pseudo mm that contains vmas. The vmas - * carry the policy. As a special twist the pseudo mm is indexed in pages, not - * bytes, so that we can work with shared memory segments bigger than - * unsigned long. */ - -struct sp_node { - struct rb_node nd; - unsigned long start, end; - struct mempolicy *policy; -}; - struct shared_policy { struct rb_root root; rwlock_t lock; }; +struct sp_node { + struct rb_node nd; + pgoff_t start, end; + struct mempolicy *policy; +}; int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst); void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol); @@ -128,7 +122,7 @@ int mpol_set_shared_policy(struct shared_policy *sp, struct vm_area_struct *vma, struct mempolicy *mpol); void mpol_free_shared_policy(struct shared_policy *sp); struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp, - unsigned long idx); + pgoff_t idx); struct mempolicy *get_task_policy(struct task_struct *p); struct mempolicy *__get_vma_policy(struct vm_area_struct *vma, @@ -214,7 +208,7 @@ static inline void mpol_free_shared_policy(struct shared_policy *sp) } static inline struct mempolicy * -mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx) +mpol_shared_policy_lookup(struct shared_policy *sp, pgoff_t idx) { return NULL; } diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 50a57f4c8013..c18f0a1b97e3 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2428,8 +2428,8 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b) * lookup first element intersecting start-end. Caller holds sp->lock for * reading or for writing */ -static struct sp_node * -sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end) +static struct sp_node *sp_lookup(struct shared_policy *sp, + pgoff_t start, pgoff_t end) { struct rb_node *n = sp->root.rb_node; @@ -2483,8 +2483,8 @@ static void sp_insert(struct shared_policy *sp, struct sp_node *new) } /* Find shared policy intersecting idx */ -struct mempolicy * -mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx) +struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp, + pgoff_t idx) { struct mempolicy *pol = NULL; struct sp_node *sn; @@ -2652,8 +2652,8 @@ static struct sp_node *sp_alloc(unsigned long start, unsigned long end, } /* Replace a policy range. */ -static int shared_policy_replace(struct shared_policy *sp, unsigned long start, - unsigned long end, struct sp_node *new) +static int shared_policy_replace(struct shared_policy *sp, pgoff_t start, + pgoff_t end, struct sp_node *new) { struct sp_node *n; struct sp_node *n_new = NULL; -- cgit v1.2.3 From ddc1a5cbc05dc62743a2f409b96faa5cf95ba064 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Thu, 19 Oct 2023 13:39:08 -0700 Subject: mempolicy: alloc_pages_mpol() for NUMA policy without vma Shrink shmem's stack usage by eliminating the pseudo-vma from its folio allocation. alloc_pages_mpol(gfp, order, pol, ilx, nid) becomes the principal actor for passing mempolicy choice down to __alloc_pages(), rather than vma_alloc_folio(gfp, order, vma, addr, hugepage). vma_alloc_folio() and alloc_pages() remain, but as wrappers around alloc_pages_mpol(). alloc_pages_bulk_*() untouched, except to provide the additional args to policy_nodemask(), which subsumes policy_node(). Cleanup throughout, cutting out some unhelpful "helpers". It would all be much simpler without MPOL_INTERLEAVE, but that adds a dynamic to the constant mpol: complicated by v3.6 commit 09c231cb8bfd ("tmpfs: distribute interleave better across nodes"), which added ino bias to the interleave, hidden from mm/mempolicy.c until this commit. Hence "ilx" throughout, the "interleave index". Originally I thought it could be done just with nid, but that's wrong: the nodemask may come from the shared policy layer below a shmem vma, or it may come from the task layer above a shmem vma; and without the final nodemask then nodeid cannot be decided. And how ilx is applied depends also on page order. The interleave index is almost always irrelevant unless MPOL_INTERLEAVE: with one exception in alloc_pages_mpol(), where the NO_INTERLEAVE_INDEX passed down from vma-less alloc_pages() is also used as hint not to use THP-style hugepage allocation - to avoid the overhead of a hugepage arg (though I don't understand why we never just added a GFP bit for THP - if it actually needs a different allocation strategy from other pages of the same order). vma_alloc_folio() still carries its hugepage arg here, but it is not used, and should be removed when agreed. get_vma_policy() no longer allows a NULL vma: over time I believe we've eradicated all the places which used to need it e.g. swapoff and madvise used to pass NULL vma to read_swap_cache_async(), but now know the vma. [hughd@google.com: handle NULL mpol being passed to __read_swap_cache_async()] Link: https://lkml.kernel.org/r/ea419956-4751-0102-21f7-9c93cb957892@google.com Link: https://lkml.kernel.org/r/74e34633-6060-f5e3-aee-7040d43f2e93@google.com Link: https://lkml.kernel.org/r/1738368e-bac0-fd11-ed7f-b87142a939fe@google.com Signed-off-by: Hugh Dickins Cc: Andi Kleen Cc: Christoph Lameter Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Huang Ying Cc: Kefeng Wang Cc: Matthew Wilcox (Oracle) Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Kravetz Cc: Nhat Pham Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Tejun heo Cc: Vishal Moola (Oracle) Cc: Yang Shi Cc: Yosry Ahmed Cc: Domenico Cerasuolo Cc: Johannes Weiner Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 5 +- include/linux/gfp.h | 10 +- include/linux/mempolicy.h | 20 ++- include/linux/mm.h | 2 +- ipc/shm.c | 21 +-- mm/mempolicy.c | 379 +++++++++++++++++++--------------------------- mm/shmem.c | 92 ++++++----- mm/swap.h | 9 +- mm/swap_state.c | 86 +++++++---- mm/zswap.c | 7 +- 10 files changed, 308 insertions(+), 323 deletions(-) (limited to 'include/linux') diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 1d994505805b..66ae1c265da3 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -2673,8 +2673,9 @@ static int show_numa_map(struct seq_file *m, void *v) struct numa_maps *md = &numa_priv->md; struct file *file = vma->vm_file; struct mm_struct *mm = vma->vm_mm; - struct mempolicy *pol; char buffer[64]; + struct mempolicy *pol; + pgoff_t ilx; int nid; if (!mm) @@ -2683,7 +2684,7 @@ static int show_numa_map(struct seq_file *m, void *v) /* Ensure we start with an empty set of numa_maps statistics. */ memset(md, 0, sizeof(*md)); - pol = __get_vma_policy(vma, vma->vm_start); + pol = __get_vma_policy(vma, vma->vm_start, &ilx); if (pol) { mpol_to_str(buffer, sizeof(buffer), pol); mpol_cond_put(pol); diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 5b917e5b9350..de292a007138 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -8,6 +8,7 @@ #include struct vm_area_struct; +struct mempolicy; /* Convert GFP flags to their corresponding migrate type */ #define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE) @@ -262,7 +263,9 @@ static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask, #ifdef CONFIG_NUMA struct page *alloc_pages(gfp_t gfp, unsigned int order); -struct folio *folio_alloc(gfp_t gfp, unsigned order); +struct page *alloc_pages_mpol(gfp_t gfp, unsigned int order, + struct mempolicy *mpol, pgoff_t ilx, int nid); +struct folio *folio_alloc(gfp_t gfp, unsigned int order); struct folio *vma_alloc_folio(gfp_t gfp, int order, struct vm_area_struct *vma, unsigned long addr, bool hugepage); #else @@ -270,6 +273,11 @@ static inline struct page *alloc_pages(gfp_t gfp_mask, unsigned int order) { return alloc_pages_node(numa_node_id(), gfp_mask, order); } +static inline struct page *alloc_pages_mpol(gfp_t gfp, unsigned int order, + struct mempolicy *mpol, pgoff_t ilx, int nid) +{ + return alloc_pages(gfp, order); +} static inline struct folio *folio_alloc(gfp_t gfp, unsigned int order) { return __folio_alloc_node(gfp, order, numa_node_id()); diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index acdb12fcb6cd..931b118336f4 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -17,6 +17,8 @@ struct mm_struct; +#define NO_INTERLEAVE_INDEX (-1UL) /* use task il_prev for interleaving */ + #ifdef CONFIG_NUMA /* @@ -126,7 +128,9 @@ struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp, struct mempolicy *get_task_policy(struct task_struct *p); struct mempolicy *__get_vma_policy(struct vm_area_struct *vma, - unsigned long addr); + unsigned long addr, pgoff_t *ilx); +struct mempolicy *get_vma_policy(struct vm_area_struct *vma, + unsigned long addr, int order, pgoff_t *ilx); bool vma_policy_mof(struct vm_area_struct *vma); extern void numa_default_policy(void); @@ -140,8 +144,6 @@ extern int huge_node(struct vm_area_struct *vma, extern bool init_nodemask_of_mempolicy(nodemask_t *mask); extern bool mempolicy_in_oom_domain(struct task_struct *tsk, const nodemask_t *mask); -extern nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy); - extern unsigned int mempolicy_slab_node(void); extern enum zone_type policy_zone; @@ -179,6 +181,11 @@ extern bool apply_policy_zone(struct mempolicy *policy, enum zone_type zone); struct mempolicy {}; +static inline struct mempolicy *get_task_policy(struct task_struct *p) +{ + return NULL; +} + static inline bool mpol_equal(struct mempolicy *a, struct mempolicy *b) { return true; @@ -213,6 +220,13 @@ mpol_shared_policy_lookup(struct shared_policy *sp, pgoff_t idx) return NULL; } +static inline struct mempolicy *get_vma_policy(struct vm_area_struct *vma, + unsigned long addr, int order, pgoff_t *ilx) +{ + *ilx = 0; + return NULL; +} + static inline int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst) { diff --git a/include/linux/mm.h b/include/linux/mm.h index 0e496a8b8e50..14d5aaff96d0 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -619,7 +619,7 @@ struct vm_operations_struct { * policy. */ struct mempolicy *(*get_policy)(struct vm_area_struct *vma, - unsigned long addr); + unsigned long addr, pgoff_t *ilx); #endif /* * Called by vm_normal_page() for special PTEs to find the diff --git a/ipc/shm.c b/ipc/shm.c index 576a543b7cff..222aaf035afb 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -562,30 +562,25 @@ static unsigned long shm_pagesize(struct vm_area_struct *vma) } #ifdef CONFIG_NUMA -static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) +static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) { - struct file *file = vma->vm_file; - struct shm_file_data *sfd = shm_file_data(file); + struct shm_file_data *sfd = shm_file_data(vma->vm_file); int err = 0; if (sfd->vm_ops->set_policy) - err = sfd->vm_ops->set_policy(vma, new); + err = sfd->vm_ops->set_policy(vma, mpol); return err; } static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, - unsigned long addr) + unsigned long addr, pgoff_t *ilx) { - struct file *file = vma->vm_file; - struct shm_file_data *sfd = shm_file_data(file); - struct mempolicy *pol = NULL; + struct shm_file_data *sfd = shm_file_data(vma->vm_file); + struct mempolicy *mpol = vma->vm_policy; if (sfd->vm_ops->get_policy) - pol = sfd->vm_ops->get_policy(vma, addr); - else if (vma->vm_policy) - pol = vma->vm_policy; - - return pol; + mpol = sfd->vm_ops->get_policy(vma, addr, ilx); + return mpol; } #endif diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 596d580f92d1..ded5508f0972 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -898,6 +898,7 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask, } if (flags & MPOL_F_ADDR) { + pgoff_t ilx; /* ignored here */ /* * Do NOT fall back to task policy if the * vma/shared policy at addr is NULL. We @@ -909,10 +910,7 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask, mmap_read_unlock(mm); return -EFAULT; } - if (vma->vm_ops && vma->vm_ops->get_policy) - pol = vma->vm_ops->get_policy(vma, addr); - else - pol = vma->vm_policy; + pol = __get_vma_policy(vma, addr, &ilx); } else if (addr) return -EINVAL; @@ -1170,6 +1168,15 @@ static struct folio *new_folio(struct folio *src, unsigned long start) break; } + /* + * __get_vma_policy() now expects a genuine non-NULL vma. Return NULL + * when the page can no longer be located in a vma: that is not ideal + * (migrate_pages() will give up early, presuming ENOMEM), but good + * enough to avoid a crash by syzkaller or concurrent holepunch. + */ + if (!vma) + return NULL; + if (folio_test_hugetlb(src)) { return alloc_hugetlb_folio_vma(folio_hstate(src), vma, address); @@ -1178,9 +1185,6 @@ static struct folio *new_folio(struct folio *src, unsigned long start) if (folio_test_large(src)) gfp = GFP_TRANSHUGE; - /* - * if !vma, vma_alloc_folio() will use task or system default policy - */ return vma_alloc_folio(gfp, folio_order(src), vma, address, folio_test_large(src)); } @@ -1690,34 +1694,19 @@ bool vma_migratable(struct vm_area_struct *vma) } struct mempolicy *__get_vma_policy(struct vm_area_struct *vma, - unsigned long addr) + unsigned long addr, pgoff_t *ilx) { - struct mempolicy *pol = NULL; - - if (vma) { - if (vma->vm_ops && vma->vm_ops->get_policy) { - pol = vma->vm_ops->get_policy(vma, addr); - } else if (vma->vm_policy) { - pol = vma->vm_policy; - - /* - * shmem_alloc_page() passes MPOL_F_SHARED policy with - * a pseudo vma whose vma->vm_ops=NULL. Take a reference - * count on these policies which will be dropped by - * mpol_cond_put() later - */ - if (mpol_needs_cond_ref(pol)) - mpol_get(pol); - } - } - - return pol; + *ilx = 0; + return (vma->vm_ops && vma->vm_ops->get_policy) ? + vma->vm_ops->get_policy(vma, addr, ilx) : vma->vm_policy; } /* - * get_vma_policy(@vma, @addr) + * get_vma_policy(@vma, @addr, @order, @ilx) * @vma: virtual memory area whose policy is sought * @addr: address in @vma for shared policy lookup + * @order: 0, or appropriate huge_page_order for interleaving + * @ilx: interleave index (output), for use only when MPOL_INTERLEAVE * * Returns effective policy for a VMA at specified address. * Falls back to current->mempolicy or system default policy, as necessary. @@ -1726,14 +1715,18 @@ struct mempolicy *__get_vma_policy(struct vm_area_struct *vma, * freeing by another task. It is the caller's responsibility to free the * extra reference for shared policies. */ -static struct mempolicy *get_vma_policy(struct vm_area_struct *vma, - unsigned long addr) +struct mempolicy *get_vma_policy(struct vm_area_struct *vma, + unsigned long addr, int order, pgoff_t *ilx) { - struct mempolicy *pol = __get_vma_policy(vma, addr); + struct mempolicy *pol; + pol = __get_vma_policy(vma, addr, ilx); if (!pol) pol = get_task_policy(current); - + if (pol->mode == MPOL_INTERLEAVE) { + *ilx += vma->vm_pgoff >> order; + *ilx += (addr - vma->vm_start) >> (PAGE_SHIFT + order); + } return pol; } @@ -1743,8 +1736,9 @@ bool vma_policy_mof(struct vm_area_struct *vma) if (vma->vm_ops && vma->vm_ops->get_policy) { bool ret = false; + pgoff_t ilx; /* ignored here */ - pol = vma->vm_ops->get_policy(vma, vma->vm_start); + pol = vma->vm_ops->get_policy(vma, vma->vm_start, &ilx); if (pol && (pol->flags & MPOL_F_MOF)) ret = true; mpol_cond_put(pol); @@ -1779,54 +1773,6 @@ bool apply_policy_zone(struct mempolicy *policy, enum zone_type zone) return zone >= dynamic_policy_zone; } -/* - * Return a nodemask representing a mempolicy for filtering nodes for - * page allocation - */ -nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy) -{ - int mode = policy->mode; - - /* Lower zones don't get a nodemask applied for MPOL_BIND */ - if (unlikely(mode == MPOL_BIND) && - apply_policy_zone(policy, gfp_zone(gfp)) && - cpuset_nodemask_valid_mems_allowed(&policy->nodes)) - return &policy->nodes; - - if (mode == MPOL_PREFERRED_MANY) - return &policy->nodes; - - return NULL; -} - -/* - * Return the preferred node id for 'prefer' mempolicy, and return - * the given id for all other policies. - * - * policy_node() is always coupled with policy_nodemask(), which - * secures the nodemask limit for 'bind' and 'prefer-many' policy. - */ -static int policy_node(gfp_t gfp, struct mempolicy *policy, int nid) -{ - if (policy->mode == MPOL_PREFERRED) { - nid = first_node(policy->nodes); - } else { - /* - * __GFP_THISNODE shouldn't even be used with the bind policy - * because we might easily break the expectation to stay on the - * requested node and not break the policy. - */ - WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE)); - } - - if ((policy->mode == MPOL_BIND || - policy->mode == MPOL_PREFERRED_MANY) && - policy->home_node != NUMA_NO_NODE) - return policy->home_node; - - return nid; -} - /* Do dynamic interleaving for a process */ static unsigned int interleave_nodes(struct mempolicy *policy) { @@ -1886,11 +1832,11 @@ unsigned int mempolicy_slab_node(void) } /* - * Do static interleaving for a VMA with known offset @n. Returns the n'th - * node in pol->nodes (starting from n=0), wrapping around if n exceeds the - * number of present nodes. + * Do static interleaving for interleave index @ilx. Returns the ilx'th + * node in pol->nodes (starting from ilx=0), wrapping around if ilx + * exceeds the number of present nodes. */ -static unsigned offset_il_node(struct mempolicy *pol, unsigned long n) +static unsigned int interleave_nid(struct mempolicy *pol, pgoff_t ilx) { nodemask_t nodemask = pol->nodes; unsigned int target, nnodes; @@ -1908,33 +1854,54 @@ static unsigned offset_il_node(struct mempolicy *pol, unsigned long n) nnodes = nodes_weight(nodemask); if (!nnodes) return numa_node_id(); - target = (unsigned int)n % nnodes; + target = ilx % nnodes; nid = first_node(nodemask); for (i = 0; i < target; i++) nid = next_node(nid, nodemask); return nid; } -/* Determine a node number for interleave */ -static inline unsigned interleave_nid(struct mempolicy *pol, - struct vm_area_struct *vma, unsigned long addr, int shift) +/* + * Return a nodemask representing a mempolicy for filtering nodes for + * page allocation, together with preferred node id (or the input node id). + */ +static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *pol, + pgoff_t ilx, int *nid) { - if (vma) { - unsigned long off; + nodemask_t *nodemask = NULL; + switch (pol->mode) { + case MPOL_PREFERRED: + /* Override input node id */ + *nid = first_node(pol->nodes); + break; + case MPOL_PREFERRED_MANY: + nodemask = &pol->nodes; + if (pol->home_node != NUMA_NO_NODE) + *nid = pol->home_node; + break; + case MPOL_BIND: + /* Restrict to nodemask (but not on lower zones) */ + if (apply_policy_zone(pol, gfp_zone(gfp)) && + cpuset_nodemask_valid_mems_allowed(&pol->nodes)) + nodemask = &pol->nodes; + if (pol->home_node != NUMA_NO_NODE) + *nid = pol->home_node; /* - * for small pages, there is no difference between - * shift and PAGE_SHIFT, so the bit-shift is safe. - * for huge pages, since vm_pgoff is in units of small - * pages, we need to shift off the always 0 bits to get - * a useful offset. + * __GFP_THISNODE shouldn't even be used with the bind policy + * because we might easily break the expectation to stay on the + * requested node and not break the policy. */ - BUG_ON(shift < PAGE_SHIFT); - off = vma->vm_pgoff >> (shift - PAGE_SHIFT); - off += (addr - vma->vm_start) >> shift; - return offset_il_node(pol, off); - } else - return interleave_nodes(pol); + WARN_ON_ONCE(gfp & __GFP_THISNODE); + break; + case MPOL_INTERLEAVE: + /* Override input node id */ + *nid = (ilx == NO_INTERLEAVE_INDEX) ? + interleave_nodes(pol) : interleave_nid(pol, ilx); + break; + } + + return nodemask; } #ifdef CONFIG_HUGETLBFS @@ -1950,27 +1917,16 @@ static inline unsigned interleave_nid(struct mempolicy *pol, * to the struct mempolicy for conditional unref after allocation. * If the effective policy is 'bind' or 'prefer-many', returns a pointer * to the mempolicy's @nodemask for filtering the zonelist. - * - * Must be protected by read_mems_allowed_begin() */ int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags, - struct mempolicy **mpol, nodemask_t **nodemask) + struct mempolicy **mpol, nodemask_t **nodemask) { + pgoff_t ilx; int nid; - int mode; - *mpol = get_vma_policy(vma, addr); - *nodemask = NULL; - mode = (*mpol)->mode; - - if (unlikely(mode == MPOL_INTERLEAVE)) { - nid = interleave_nid(*mpol, vma, addr, - huge_page_shift(hstate_vma(vma))); - } else { - nid = policy_node(gfp_flags, *mpol, numa_node_id()); - if (mode == MPOL_BIND || mode == MPOL_PREFERRED_MANY) - *nodemask = &(*mpol)->nodes; - } + nid = numa_node_id(); + *mpol = get_vma_policy(vma, addr, hstate_vma(vma)->order, &ilx); + *nodemask = policy_nodemask(gfp_flags, *mpol, ilx, &nid); return nid; } @@ -2048,27 +2004,8 @@ bool mempolicy_in_oom_domain(struct task_struct *tsk, return ret; } -/* Allocate a page in interleaved policy. - Own path because it needs to do special accounting. */ -static struct page *alloc_page_interleave(gfp_t gfp, unsigned order, - unsigned nid) -{ - struct page *page; - - page = __alloc_pages(gfp, order, nid, NULL); - /* skip NUMA_INTERLEAVE_HIT counter update if numa stats is disabled */ - if (!static_branch_likely(&vm_numa_stat_key)) - return page; - if (page && page_to_nid(page) == nid) { - preempt_disable(); - __count_numa_event(page_zone(page), NUMA_INTERLEAVE_HIT); - preempt_enable(); - } - return page; -} - static struct page *alloc_pages_preferred_many(gfp_t gfp, unsigned int order, - int nid, struct mempolicy *pol) + int nid, nodemask_t *nodemask) { struct page *page; gfp_t preferred_gfp; @@ -2081,7 +2018,7 @@ static struct page *alloc_pages_preferred_many(gfp_t gfp, unsigned int order, */ preferred_gfp = gfp | __GFP_NOWARN; preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL); - page = __alloc_pages(preferred_gfp, order, nid, &pol->nodes); + page = __alloc_pages(preferred_gfp, order, nid, nodemask); if (!page) page = __alloc_pages(gfp, order, nid, NULL); @@ -2089,55 +2026,29 @@ static struct page *alloc_pages_preferred_many(gfp_t gfp, unsigned int order, } /** - * vma_alloc_folio - Allocate a folio for a VMA. + * alloc_pages_mpol - Allocate pages according to NUMA mempolicy. * @gfp: GFP flags. - * @order: Order of the folio. - * @vma: Pointer to VMA or NULL if not available. - * @addr: Virtual address of the allocation. Must be inside @vma. - * @hugepage: For hugepages try only the preferred node if possible. - * - * Allocate a folio for a specific address in @vma, using the appropriate - * NUMA policy. When @vma is not NULL the caller must hold the mmap_lock - * of the mm_struct of the VMA to prevent it from going away. Should be - * used for all allocations for folios that will be mapped into user space. + * @order: Order of the page allocation. + * @pol: Pointer to the NUMA mempolicy. + * @ilx: Index for interleave mempolicy (also distinguishes alloc_pages()). + * @nid: Preferred node (usually numa_node_id() but @mpol may override it). * - * Return: The folio on success or NULL if allocation fails. + * Return: The page on success or NULL if allocation fails. */ -struct folio *vma_alloc_folio(gfp_t gfp, int order, struct vm_area_struct *vma, - unsigned long addr, bool hugepage) +struct page *alloc_pages_mpol(gfp_t gfp, unsigned int order, + struct mempolicy *pol, pgoff_t ilx, int nid) { - struct mempolicy *pol; - int node = numa_node_id(); - struct folio *folio; - int preferred_nid; - nodemask_t *nmask; - - pol = get_vma_policy(vma, addr); - - if (pol->mode == MPOL_INTERLEAVE) { - struct page *page; - unsigned nid; - - nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order); - mpol_cond_put(pol); - gfp |= __GFP_COMP; - page = alloc_page_interleave(gfp, order, nid); - return page_rmappable_folio(page); - } - - if (pol->mode == MPOL_PREFERRED_MANY) { - struct page *page; + nodemask_t *nodemask; + struct page *page; - node = policy_node(gfp, pol, node); - gfp |= __GFP_COMP; - page = alloc_pages_preferred_many(gfp, order, node, pol); - mpol_cond_put(pol); - return page_rmappable_folio(page); - } + nodemask = policy_nodemask(gfp, pol, ilx, &nid); - if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) { - int hpage_node = node; + if (pol->mode == MPOL_PREFERRED_MANY) + return alloc_pages_preferred_many(gfp, order, nid, nodemask); + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && + /* filter "hugepage" allocation, unless from alloc_pages() */ + order == HPAGE_PMD_ORDER && ilx != NO_INTERLEAVE_INDEX) { /* * For hugepage allocation and non-interleave policy which * allows the current node (or other explicitly preferred @@ -2148,39 +2059,68 @@ struct folio *vma_alloc_folio(gfp_t gfp, int order, struct vm_area_struct *vma, * If the policy is interleave or does not allow the current * node in its nodemask, we allocate the standard way. */ - if (pol->mode == MPOL_PREFERRED) - hpage_node = first_node(pol->nodes); - - nmask = policy_nodemask(gfp, pol); - if (!nmask || node_isset(hpage_node, *nmask)) { - mpol_cond_put(pol); + if (pol->mode != MPOL_INTERLEAVE && + (!nodemask || node_isset(nid, *nodemask))) { /* * First, try to allocate THP only on local node, but * don't reclaim unnecessarily, just compact. */ - folio = __folio_alloc_node(gfp | __GFP_THISNODE | - __GFP_NORETRY, order, hpage_node); - + page = __alloc_pages_node(nid, + gfp | __GFP_THISNODE | __GFP_NORETRY, order); + if (page || !(gfp & __GFP_DIRECT_RECLAIM)) + return page; /* * If hugepage allocations are configured to always * synchronous compact or the vma has been madvised * to prefer hugepage backing, retry allowing remote * memory with both reclaim and compact as well. */ - if (!folio && (gfp & __GFP_DIRECT_RECLAIM)) - folio = __folio_alloc(gfp, order, hpage_node, - nmask); + } + } - goto out; + page = __alloc_pages(gfp, order, nid, nodemask); + + if (unlikely(pol->mode == MPOL_INTERLEAVE) && page) { + /* skip NUMA_INTERLEAVE_HIT update if numa stats is disabled */ + if (static_branch_likely(&vm_numa_stat_key) && + page_to_nid(page) == nid) { + preempt_disable(); + __count_numa_event(page_zone(page), NUMA_INTERLEAVE_HIT); + preempt_enable(); } } - nmask = policy_nodemask(gfp, pol); - preferred_nid = policy_node(gfp, pol, node); - folio = __folio_alloc(gfp, order, preferred_nid, nmask); + return page; +} + +/** + * vma_alloc_folio - Allocate a folio for a VMA. + * @gfp: GFP flags. + * @order: Order of the folio. + * @vma: Pointer to VMA. + * @addr: Virtual address of the allocation. Must be inside @vma. + * @hugepage: Unused (was: For hugepages try only preferred node if possible). + * + * Allocate a folio for a specific address in @vma, using the appropriate + * NUMA policy. The caller must hold the mmap_lock of the mm_struct of the + * VMA to prevent it from going away. Should be used for all allocations + * for folios that will be mapped into user space, excepting hugetlbfs, and + * excepting where direct use of alloc_pages_mpol() is more appropriate. + * + * Return: The folio on success or NULL if allocation fails. + */ +struct folio *vma_alloc_folio(gfp_t gfp, int order, struct vm_area_struct *vma, + unsigned long addr, bool hugepage) +{ + struct mempolicy *pol; + pgoff_t ilx; + struct page *page; + + pol = get_vma_policy(vma, addr, order, &ilx); + page = alloc_pages_mpol(gfp | __GFP_COMP, order, + pol, ilx, numa_node_id()); mpol_cond_put(pol); -out: - return folio; + return page_rmappable_folio(page); } EXPORT_SYMBOL(vma_alloc_folio); @@ -2198,33 +2138,23 @@ EXPORT_SYMBOL(vma_alloc_folio); * flags are used. * Return: The page on success or NULL if allocation fails. */ -struct page *alloc_pages(gfp_t gfp, unsigned order) +struct page *alloc_pages(gfp_t gfp, unsigned int order) { struct mempolicy *pol = &default_policy; - struct page *page; - - if (!in_interrupt() && !(gfp & __GFP_THISNODE)) - pol = get_task_policy(current); /* * No reference counting needed for current->mempolicy * nor system default_policy */ - if (pol->mode == MPOL_INTERLEAVE) - page = alloc_page_interleave(gfp, order, interleave_nodes(pol)); - else if (pol->mode == MPOL_PREFERRED_MANY) - page = alloc_pages_preferred_many(gfp, order, - policy_node(gfp, pol, numa_node_id()), pol); - else - page = __alloc_pages(gfp, order, - policy_node(gfp, pol, numa_node_id()), - policy_nodemask(gfp, pol)); + if (!in_interrupt() && !(gfp & __GFP_THISNODE)) + pol = get_task_policy(current); - return page; + return alloc_pages_mpol(gfp, order, + pol, NO_INTERLEAVE_INDEX, numa_node_id()); } EXPORT_SYMBOL(alloc_pages); -struct folio *folio_alloc(gfp_t gfp, unsigned order) +struct folio *folio_alloc(gfp_t gfp, unsigned int order) { return page_rmappable_folio(alloc_pages(gfp | __GFP_COMP, order)); } @@ -2295,6 +2225,8 @@ unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp, unsigned long nr_pages, struct page **page_array) { struct mempolicy *pol = &default_policy; + nodemask_t *nodemask; + int nid; if (!in_interrupt() && !(gfp & __GFP_THISNODE)) pol = get_task_policy(current); @@ -2307,9 +2239,10 @@ unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp, return alloc_pages_bulk_array_preferred_many(gfp, numa_node_id(), pol, nr_pages, page_array); - return __alloc_pages_bulk(gfp, policy_node(gfp, pol, numa_node_id()), - policy_nodemask(gfp, pol), nr_pages, NULL, - page_array); + nid = numa_node_id(); + nodemask = policy_nodemask(gfp, pol, NO_INTERLEAVE_INDEX, &nid); + return __alloc_pages_bulk(gfp, nid, nodemask, + nr_pages, NULL, page_array); } int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst) @@ -2496,23 +2429,21 @@ int mpol_misplaced(struct folio *folio, struct vm_area_struct *vma, unsigned long addr) { struct mempolicy *pol; + pgoff_t ilx; struct zoneref *z; int curnid = folio_nid(folio); - unsigned long pgoff; int thiscpu = raw_smp_processor_id(); int thisnid = cpu_to_node(thiscpu); int polnid = NUMA_NO_NODE; int ret = NUMA_NO_NODE; - pol = get_vma_policy(vma, addr); + pol = get_vma_policy(vma, addr, folio_order(folio), &ilx); if (!(pol->flags & MPOL_F_MOF)) goto out; switch (pol->mode) { case MPOL_INTERLEAVE: - pgoff = vma->vm_pgoff; - pgoff += (addr - vma->vm_start) >> PAGE_SHIFT; - polnid = offset_il_node(pol, pgoff); + polnid = interleave_nid(pol, ilx); break; case MPOL_PREFERRED: diff --git a/mm/shmem.c b/mm/shmem.c index bcbe9dbb9f5f..a314a25aea8c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1544,38 +1544,20 @@ static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) return NULL; } #endif /* CONFIG_NUMA && CONFIG_TMPFS */ -#ifndef CONFIG_NUMA -#define vm_policy vm_private_data -#endif - -static void shmem_pseudo_vma_init(struct vm_area_struct *vma, - struct shmem_inode_info *info, pgoff_t index) -{ - /* Create a pseudo vma that just contains the policy */ - vma_init(vma, NULL); - /* Bias interleave by inode number to distribute better across nodes */ - vma->vm_pgoff = index + info->vfs_inode.i_ino; - vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index); -} -static void shmem_pseudo_vma_destroy(struct vm_area_struct *vma) -{ - /* Drop reference taken by mpol_shared_policy_lookup() */ - mpol_cond_put(vma->vm_policy); -} +static struct mempolicy *shmem_get_pgoff_policy(struct shmem_inode_info *info, + pgoff_t index, unsigned int order, pgoff_t *ilx); -static struct folio *shmem_swapin(swp_entry_t swap, gfp_t gfp, +static struct folio *shmem_swapin_cluster(swp_entry_t swap, gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { - struct vm_area_struct pvma; + struct mempolicy *mpol; + pgoff_t ilx; struct page *page; - struct vm_fault vmf = { - .vma = &pvma, - }; - shmem_pseudo_vma_init(&pvma, info, index); - page = swap_cluster_readahead(swap, gfp, &vmf); - shmem_pseudo_vma_destroy(&pvma); + mpol = shmem_get_pgoff_policy(info, index, 0, &ilx); + page = swap_cluster_readahead(swap, gfp, mpol, ilx); + mpol_cond_put(mpol); if (!page) return NULL; @@ -1609,27 +1591,29 @@ static gfp_t limit_gfp_mask(gfp_t huge_gfp, gfp_t limit_gfp) static struct folio *shmem_alloc_hugefolio(gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { - struct vm_area_struct pvma; - struct folio *folio; + struct mempolicy *mpol; + pgoff_t ilx; + struct page *page; - shmem_pseudo_vma_init(&pvma, info, index); - folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, &pvma, 0, true); - shmem_pseudo_vma_destroy(&pvma); + mpol = shmem_get_pgoff_policy(info, index, HPAGE_PMD_ORDER, &ilx); + page = alloc_pages_mpol(gfp, HPAGE_PMD_ORDER, mpol, ilx, numa_node_id()); + mpol_cond_put(mpol); - return folio; + return page_rmappable_folio(page); } static struct folio *shmem_alloc_folio(gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { - struct vm_area_struct pvma; - struct folio *folio; + struct mempolicy *mpol; + pgoff_t ilx; + struct page *page; - shmem_pseudo_vma_init(&pvma, info, index); - folio = vma_alloc_folio(gfp, 0, &pvma, 0, false); - shmem_pseudo_vma_destroy(&pvma); + mpol = shmem_get_pgoff_policy(info, index, 0, &ilx); + page = alloc_pages_mpol(gfp, 0, mpol, ilx, numa_node_id()); + mpol_cond_put(mpol); - return folio; + return (struct folio *)page; } static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, @@ -1883,7 +1867,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, count_memcg_event_mm(fault_mm, PGMAJFAULT); } /* Here we actually start the io */ - folio = shmem_swapin(swap, gfp, info, index); + folio = shmem_swapin_cluster(swap, gfp, info, index); if (!folio) { error = -ENOMEM; goto failed; @@ -2334,15 +2318,41 @@ static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) } static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, - unsigned long addr) + unsigned long addr, pgoff_t *ilx) { struct inode *inode = file_inode(vma->vm_file); pgoff_t index; + /* + * Bias interleave by inode number to distribute better across nodes; + * but this interface is independent of which page order is used, so + * supplies only that bias, letting caller apply the offset (adjusted + * by page order, as in shmem_get_pgoff_policy() and get_vma_policy()). + */ + *ilx = inode->i_ino; index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); } -#endif + +static struct mempolicy *shmem_get_pgoff_policy(struct shmem_inode_info *info, + pgoff_t index, unsigned int order, pgoff_t *ilx) +{ + struct mempolicy *mpol; + + /* Bias interleave by inode number to distribute better across nodes */ + *ilx = info->vfs_inode.i_ino + (index >> order); + + mpol = mpol_shared_policy_lookup(&info->policy, index); + return mpol ? mpol : get_task_policy(current); +} +#else +static struct mempolicy *shmem_get_pgoff_policy(struct shmem_inode_info *info, + pgoff_t index, unsigned int order, pgoff_t *ilx) +{ + *ilx = 0; + return NULL; +} +#endif /* CONFIG_NUMA */ int shmem_lock(struct file *file, int lock, struct ucounts *ucounts) { diff --git a/mm/swap.h b/mm/swap.h index 8a3c7a0ace4f..73c332ee4d91 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -2,6 +2,8 @@ #ifndef _MM_SWAP_H #define _MM_SWAP_H +struct mempolicy; + #ifdef CONFIG_SWAP #include /* for bio_end_io_t */ @@ -48,11 +50,10 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, unsigned long addr, struct swap_iocb **plug); struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, - struct vm_area_struct *vma, - unsigned long addr, + struct mempolicy *mpol, pgoff_t ilx, bool *new_page_allocated); struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, - struct vm_fault *vmf); + struct mempolicy *mpol, pgoff_t ilx); struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, struct vm_fault *vmf); @@ -80,7 +81,7 @@ static inline void show_swap_cache_info(void) } static inline struct page *swap_cluster_readahead(swp_entry_t entry, - gfp_t gfp_mask, struct vm_fault *vmf) + gfp_t gfp_mask, struct mempolicy *mpol, pgoff_t ilx) { return NULL; } diff --git a/mm/swap_state.c b/mm/swap_state.c index ab79ffb71736..85d9e5806a6a 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -410,8 +411,8 @@ struct folio *filemap_get_incore_folio(struct address_space *mapping, } struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, - struct vm_area_struct *vma, unsigned long addr, - bool *new_page_allocated) + struct mempolicy *mpol, pgoff_t ilx, + bool *new_page_allocated) { struct swap_info_struct *si; struct folio *folio; @@ -453,7 +454,8 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, * before marking swap_map SWAP_HAS_CACHE, when -EEXIST will * cause any racers to loop around until we add it to cache. */ - folio = vma_alloc_folio(gfp_mask, 0, vma, addr, false); + folio = (struct folio *)alloc_pages_mpol(gfp_mask, 0, + mpol, ilx, numa_node_id()); if (!folio) goto fail_put_swap; @@ -528,14 +530,19 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, struct vm_area_struct *vma, unsigned long addr, struct swap_iocb **plug) { - bool page_was_allocated; - struct page *retpage = __read_swap_cache_async(entry, gfp_mask, - vma, addr, &page_was_allocated); + bool page_allocated; + struct mempolicy *mpol; + pgoff_t ilx; + struct page *page; - if (page_was_allocated) - swap_readpage(retpage, false, plug); + mpol = get_vma_policy(vma, addr, 0, &ilx); + page = __read_swap_cache_async(entry, gfp_mask, mpol, ilx, + &page_allocated); + mpol_cond_put(mpol); - return retpage; + if (page_allocated) + swap_readpage(page, false, plug); + return page; } static unsigned int __swapin_nr_pages(unsigned long prev_offset, @@ -603,7 +610,8 @@ static unsigned long swapin_nr_pages(unsigned long offset) * swap_cluster_readahead - swap in pages in hope we need them soon * @entry: swap entry of this memory * @gfp_mask: memory allocation flags - * @vmf: fault information + * @mpol: NUMA memory allocation policy to be applied + * @ilx: NUMA interleave index, for use only when MPOL_INTERLEAVE * * Returns the struct page for entry and addr, after queueing swapin. * @@ -612,13 +620,12 @@ static unsigned long swapin_nr_pages(unsigned long offset) * because it doesn't cost us any seek time. We also make sure to queue * the 'original' request together with the readahead ones... * - * This has been extended to use the NUMA policies from the mm triggering - * the readahead. - * - * Caller must hold read mmap_lock if vmf->vma is not NULL. + * Note: it is intentional that the same NUMA policy and interleave index + * are used for every page of the readahead: neighbouring pages on swap + * are fairly likely to have been swapped out from the same node. */ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, - struct vm_fault *vmf) + struct mempolicy *mpol, pgoff_t ilx) { struct page *page; unsigned long entry_offset = swp_offset(entry); @@ -629,8 +636,6 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, struct blk_plug plug; struct swap_iocb *splug = NULL; bool page_allocated; - struct vm_area_struct *vma = vmf->vma; - unsigned long addr = vmf->address; mask = swapin_nr_pages(offset) - 1; if (!mask) @@ -648,8 +653,8 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, for (offset = start_offset; offset <= end_offset ; offset++) { /* Ok, do the async read-ahead now */ page = __read_swap_cache_async( - swp_entry(swp_type(entry), offset), - gfp_mask, vma, addr, &page_allocated); + swp_entry(swp_type(entry), offset), + gfp_mask, mpol, ilx, &page_allocated); if (!page) continue; if (page_allocated) { @@ -663,11 +668,14 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, } blk_finish_plug(&plug); swap_read_unplug(splug); - lru_add_drain(); /* Push any new pages onto the LRU now */ skip: /* The page was likely read above, so no need for plugging here */ - return read_swap_cache_async(entry, gfp_mask, vma, addr, NULL); + page = __read_swap_cache_async(entry, gfp_mask, mpol, ilx, + &page_allocated); + if (unlikely(page_allocated)) + swap_readpage(page, false, NULL); + return page; } int init_swap_address_space(unsigned int type, unsigned long nr_pages) @@ -765,8 +773,10 @@ static void swap_ra_info(struct vm_fault *vmf, /** * swap_vma_readahead - swap in pages in hope we need them soon - * @fentry: swap entry of this memory + * @targ_entry: swap entry of the targeted memory * @gfp_mask: memory allocation flags + * @mpol: NUMA memory allocation policy to be applied + * @targ_ilx: NUMA interleave index, for use only when MPOL_INTERLEAVE * @vmf: fault information * * Returns the struct page for entry and addr, after queueing swapin. @@ -777,16 +787,17 @@ static void swap_ra_info(struct vm_fault *vmf, * Caller must hold read mmap_lock if vmf->vma is not NULL. * */ -static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask, +static struct page *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask, + struct mempolicy *mpol, pgoff_t targ_ilx, struct vm_fault *vmf) { struct blk_plug plug; struct swap_iocb *splug = NULL; - struct vm_area_struct *vma = vmf->vma; struct page *page; pte_t *pte = NULL, pentry; unsigned long addr; swp_entry_t entry; + pgoff_t ilx; unsigned int i; bool page_allocated; struct vma_swap_readahead ra_info = { @@ -798,9 +809,10 @@ static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask, goto skip; addr = vmf->address - (ra_info.offset * PAGE_SIZE); + ilx = targ_ilx - ra_info.offset; blk_start_plug(&plug); - for (i = 0; i < ra_info.nr_pte; i++, addr += PAGE_SIZE) { + for (i = 0; i < ra_info.nr_pte; i++, ilx++, addr += PAGE_SIZE) { if (!pte++) { pte = pte_offset_map(vmf->pmd, addr); if (!pte) @@ -814,8 +826,8 @@ static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask, continue; pte_unmap(pte); pte = NULL; - page = __read_swap_cache_async(entry, gfp_mask, vma, - addr, &page_allocated); + page = __read_swap_cache_async(entry, gfp_mask, mpol, ilx, + &page_allocated); if (!page) continue; if (page_allocated) { @@ -834,8 +846,11 @@ static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask, lru_add_drain(); skip: /* The page was likely read above, so no need for plugging here */ - return read_swap_cache_async(fentry, gfp_mask, vma, vmf->address, - NULL); + page = __read_swap_cache_async(targ_entry, gfp_mask, mpol, targ_ilx, + &page_allocated); + if (unlikely(page_allocated)) + swap_readpage(page, false, NULL); + return page; } /** @@ -853,9 +868,16 @@ skip: struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, struct vm_fault *vmf) { - return swap_use_vma_readahead() ? - swap_vma_readahead(entry, gfp_mask, vmf) : - swap_cluster_readahead(entry, gfp_mask, vmf); + struct mempolicy *mpol; + pgoff_t ilx; + struct page *page; + + mpol = get_vma_policy(vmf->vma, vmf->address, 0, &ilx); + page = swap_use_vma_readahead() ? + swap_vma_readahead(entry, gfp_mask, mpol, ilx, vmf) : + swap_cluster_readahead(entry, gfp_mask, mpol, ilx); + mpol_cond_put(mpol); + return page; } #ifdef CONFIG_SYSFS diff --git a/mm/zswap.c b/mm/zswap.c index 37d2b1cb2ecb..060857adca76 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -1057,6 +1058,7 @@ static int zswap_writeback_entry(struct zswap_entry *entry, { swp_entry_t swpentry = entry->swpentry; struct page *page; + struct mempolicy *mpol; struct scatterlist input, output; struct crypto_acomp_ctx *acomp_ctx; struct zpool *pool = zswap_find_zpool(entry); @@ -1075,8 +1077,9 @@ static int zswap_writeback_entry(struct zswap_entry *entry, } /* try to allocate swap cache page */ - page = __read_swap_cache_async(swpentry, GFP_KERNEL, NULL, 0, - &page_was_allocated); + mpol = get_task_policy(current); + page = __read_swap_cache_async(swpentry, GFP_KERNEL, mpol, + NO_INTERLEAVE_INDEX, &page_was_allocated); if (!page) { ret = -ENOMEM; goto fail; -- cgit v1.2.3 From 72e315f7a750281b4410ac30d8930f735459e72d Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 3 Oct 2023 02:27:47 -0700 Subject: mempolicy: mmap_lock is not needed while migrating folios mbind(2) holds down_write of current task's mmap_lock throughout (exclusive because it needs to set the new mempolicy on the vmas); migrate_pages(2) holds down_read of pid's mmap_lock throughout. They both hold mmap_lock across the internal migrate_pages(), under which all new page allocations (huge or small) are made. I'm nervous about it; and migrate_pages() certainly does not need mmap_lock itself. It's done this way for mbind(2), because its page allocator is vma_alloc_folio() or alloc_hugetlb_folio_vma(), both of which depend on vma and address. Now that we have alloc_pages_mpol(), depending on (refcounted) memory policy and interleave index, mbind(2) can be modified to use that or alloc_hugetlb_folio_nodemask(), and then not need mmap_lock across the internal migrate_pages() at all: add alloc_migration_target_by_mpol() to replace mbind's new_page(). (After that change, alloc_hugetlb_folio_vma() is used by nothing but a userfaultfd function: move it out of hugetlb.h and into the #ifdef.) migrate_pages(2) has chosen its target node before migrating, so can continue to use the standard alloc_migration_target(); but let it take and drop mmap_lock just around migrate_to_node()'s queue_pages_range(): neither the node-to-node calculations nor the page migrations need it. It seems unlikely, but it is conceivable that some userspace depends on the kernel's mmap_lock exclusion here, instead of doing its own locking: more likely in a testsuite than in real life. It is also possible, of course, that some pages on the list will be munmapped by another thread before they are migrated, or a newer memory policy applied to the range by that time: but such races could happen before, as soon as mmap_lock was dropped, so it does not appear to be a concern. Link: https://lkml.kernel.org/r/21e564e8-269f-6a89-7ee2-fd612831c289@google.com Signed-off-by: Hugh Dickins Cc: Andi Kleen Cc: Christoph Lameter Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "Huang, Ying" Cc: Kefeng Wang Cc: Matthew Wilcox (Oracle) Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Kravetz Cc: Nhat Pham Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Tejun heo Cc: Vishal Moola (Oracle) Cc: Yang Shi Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- include/linux/hugetlb.h | 9 ------ mm/hugetlb.c | 38 +++++++++++----------- mm/mempolicy.c | 83 +++++++++++++++++++++++++------------------------ 3 files changed, 63 insertions(+), 67 deletions(-) (limited to 'include/linux') diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 158ff156710b..d3acecc5db4b 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -748,8 +748,6 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, unsigned long addr, int avoid_reserve); struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, nodemask_t *nmask, gfp_t gfp_mask); -struct folio *alloc_hugetlb_folio_vma(struct hstate *h, struct vm_area_struct *vma, - unsigned long address); int hugetlb_add_to_page_cache(struct folio *folio, struct address_space *mapping, pgoff_t idx); void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma, @@ -1072,13 +1070,6 @@ alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, return NULL; } -static inline struct folio *alloc_hugetlb_folio_vma(struct hstate *h, - struct vm_area_struct *vma, - unsigned long address) -{ - return NULL; -} - static inline int __alloc_bootmem_huge_page(struct hstate *h) { return 0; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index dd8065e36038..1169ef2f2176 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2630,24 +2630,6 @@ struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, return alloc_migrate_hugetlb_folio(h, gfp_mask, preferred_nid, nmask); } -/* mempolicy aware migration callback */ -struct folio *alloc_hugetlb_folio_vma(struct hstate *h, struct vm_area_struct *vma, - unsigned long address) -{ - struct mempolicy *mpol; - nodemask_t *nodemask; - struct folio *folio; - gfp_t gfp_mask; - int node; - - gfp_mask = htlb_alloc_mask(h); - node = huge_node(vma, address, gfp_mask, &mpol, &nodemask); - folio = alloc_hugetlb_folio_nodemask(h, node, nodemask, gfp_mask); - mpol_cond_put(mpol); - - return folio; -} - /* * Increase the hugetlb pool such that it can accommodate a reservation * of size 'delta'. @@ -6559,6 +6541,26 @@ out_mutex: } #ifdef CONFIG_USERFAULTFD +/* + * Can probably be eliminated, but still used by hugetlb_mfill_atomic_pte(). + */ +static struct folio *alloc_hugetlb_folio_vma(struct hstate *h, + struct vm_area_struct *vma, unsigned long address) +{ + struct mempolicy *mpol; + nodemask_t *nodemask; + struct folio *folio; + gfp_t gfp_mask; + int node; + + gfp_mask = htlb_alloc_mask(h); + node = huge_node(vma, address, gfp_mask, &mpol, &nodemask); + folio = alloc_hugetlb_folio_nodemask(h, node, nodemask, gfp_mask); + mpol_cond_put(mpol); + + return folio; +} + /* * Used by userfaultfd UFFDIO_* ioctls. Based on userfaultfd's mfill_atomic_pte * with modifications for hugetlb pages. diff --git a/mm/mempolicy.c b/mm/mempolicy.c index ded5508f0972..0594362f2470 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -415,6 +415,8 @@ static const struct mempolicy_operations mpol_ops[MPOL_MAX] = { static bool migrate_folio_add(struct folio *folio, struct list_head *foliolist, unsigned long flags); +static nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *pol, + pgoff_t ilx, int *nid); static bool strictly_unmovable(unsigned long flags) { @@ -1021,6 +1023,8 @@ static long migrate_to_node(struct mm_struct *mm, int source, int dest, node_set(source, nmask); VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))); + + mmap_read_lock(mm); vma = find_vma(mm, 0); /* @@ -1031,6 +1035,7 @@ static long migrate_to_node(struct mm_struct *mm, int source, int dest, */ nr_failed = queue_pages_range(mm, vma->vm_start, mm->task_size, &nmask, flags | MPOL_MF_DISCONTIG_OK, &pagelist); + mmap_read_unlock(mm); if (!list_empty(&pagelist)) { err = migrate_pages(&pagelist, alloc_migration_target, NULL, @@ -1059,8 +1064,6 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, lru_cache_disable(); - mmap_read_lock(mm); - /* * Find a 'source' bit set in 'tmp' whose corresponding 'dest' * bit in 'to' is not also set in 'tmp'. Clear the found 'source' @@ -1140,7 +1143,6 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, if (err < 0) break; } - mmap_read_unlock(mm); lru_cache_enable(); if (err < 0) @@ -1149,44 +1151,38 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, } /* - * Allocate a new page for page migration based on vma policy. - * Start by assuming the page is mapped by the same vma as contains @start. - * Search forward from there, if not. N.B., this assumes that the - * list of pages handed to migrate_pages()--which is how we get here-- - * is in virtual address order. + * Allocate a new folio for page migration, according to NUMA mempolicy. */ -static struct folio *new_folio(struct folio *src, unsigned long start) +static struct folio *alloc_migration_target_by_mpol(struct folio *src, + unsigned long private) { - struct vm_area_struct *vma; - unsigned long address; - VMA_ITERATOR(vmi, current->mm, start); - gfp_t gfp = GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL; - - for_each_vma(vmi, vma) { - address = page_address_in_vma(&src->page, vma); - if (address != -EFAULT) - break; - } + struct mempolicy *pol = (struct mempolicy *)private; + pgoff_t ilx = 0; /* improve on this later */ + struct page *page; + unsigned int order; + int nid = numa_node_id(); + gfp_t gfp; - /* - * __get_vma_policy() now expects a genuine non-NULL vma. Return NULL - * when the page can no longer be located in a vma: that is not ideal - * (migrate_pages() will give up early, presuming ENOMEM), but good - * enough to avoid a crash by syzkaller or concurrent holepunch. - */ - if (!vma) - return NULL; + order = folio_order(src); + ilx += src->index >> order; if (folio_test_hugetlb(src)) { - return alloc_hugetlb_folio_vma(folio_hstate(src), - vma, address); + nodemask_t *nodemask; + struct hstate *h; + + h = folio_hstate(src); + gfp = htlb_alloc_mask(h); + nodemask = policy_nodemask(gfp, pol, ilx, &nid); + return alloc_hugetlb_folio_nodemask(h, nid, nodemask, gfp); } if (folio_test_large(src)) gfp = GFP_TRANSHUGE; + else + gfp = GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL | __GFP_COMP; - return vma_alloc_folio(gfp, folio_order(src), vma, address, - folio_test_large(src)); + page = alloc_pages_mpol(gfp, order, pol, ilx, nid); + return page_rmappable_folio(page); } #else @@ -1202,7 +1198,8 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, return -ENOSYS; } -static struct folio *new_folio(struct folio *src, unsigned long start) +static struct folio *alloc_migration_target_by_mpol(struct folio *src, + unsigned long private) { return NULL; } @@ -1276,6 +1273,7 @@ static long do_mbind(unsigned long start, unsigned long len, if (nr_failed < 0) { err = nr_failed; + nr_failed = 0; } else { vma_iter_init(&vmi, mm, start); prev = vma_prev(&vmi); @@ -1286,19 +1284,24 @@ static long do_mbind(unsigned long start, unsigned long len, } } - if (!err) { - if (!list_empty(&pagelist)) { - nr_failed |= migrate_pages(&pagelist, new_folio, NULL, - start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND, NULL); + mmap_write_unlock(mm); + + if (!err && !list_empty(&pagelist)) { + /* Convert MPOL_DEFAULT's NULL to task or default policy */ + if (!new) { + new = get_task_policy(current); + mpol_get(new); } - if (nr_failed && (flags & MPOL_MF_STRICT)) - err = -EIO; + nr_failed |= migrate_pages(&pagelist, + alloc_migration_target_by_mpol, NULL, + (unsigned long)new, MIGRATE_SYNC, + MR_MEMPOLICY_MBIND, NULL); } + if (nr_failed && (flags & MPOL_MF_STRICT)) + err = -EIO; if (!list_empty(&pagelist)) putback_movable_pages(&pagelist); - - mmap_write_unlock(mm); mpol_out: mpol_put(new); if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) -- cgit v1.2.3