kernel/mm/mmap.c, branch 0x221E-v0.0.1-v6.19

mm: softdirty: add pgtable_supports_soft_dirty()

2025-11-24T23:08:54Z

Patch series "mm: Add soft-dirty and uffd-wp support for RISC-V", v15. This patchset adds support for Svrsw60t59b [1] extension which is ratified now, also add soft dirty and userfaultfd write protect tracking for RISC-V. The patches 1 and 2 add macros to allow architectures to define their own checks if the soft-dirty / uffd_wp PTE bits are available, in other words for RISC-V, the Svrsw60t59b extension is supported on which device the kernel is running. Also patch1-2 are removing "ifdef CONFIG_MEM_SOFT_DIRTY" "ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP" and "ifdef CONFIG_PTE_MARKER_UFFD_WP" in favor of checks which if not overridden by the architecture, no change in behavior is expected. This patchset has been tested with kselftest mm suite in which soft-dirty, madv_populate, test_unmerge_uffd_wp, and uffd-unit-tests run and pass, and no regressions are observed in any of the other tests. This patch (of 6): Some platforms can customize the PTE PMD entry soft-dirty bit making it unavailable even if the architecture provides the resource. Add an API which architectures can define their specific implementations to detect if soft-dirty bit is available on which device the kernel is running. This patch is removing "ifdef CONFIG_MEM_SOFT_DIRTY" in favor of pgtable_supports_soft_dirty() checks that defaults to IS_ENABLED(CONFIG_MEM_SOFT_DIRTY), if not overridden by the architecture, no change in behavior is expected. We make sure to never set VM_SOFTDIRTY if !pgtable_supports_soft_dirty(), so we will never run into VM_SOFTDIRTY checks. [lorenzo.stoakes@oracle.com: fix VMA selftests] Link: https://lkml.kernel.org/r/dac6ddfe-773a-43d5-8f69-021b9ca4d24b@lucifer.local Link: https://lkml.kernel.org/r/20251113072806.795029-1-zhangchunyan@iscas.ac.cn Link: https://lkml.kernel.org/r/20251113072806.795029-2-zhangchunyan@iscas.ac.cn Link: https://github.com/riscv-non-isa/riscv-iommu/pull/543 [1] Signed-off-by: Chunyan Zhang Acked-by: David Hildenbrand Cc: Albert Ou Cc: Alexandre Ghiti Cc: Al Viro Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Christian Brauner Cc: Conor Dooley Cc: Deepak Gupta Cc: Jan Kara Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Xu Cc: Rob Herring Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Yuanchu Xie Cc: Alexandre Ghiti Cc: Andrew Jones Cc: Conor Dooley Signed-off-by: Andrew Morton

mm: use vma_start_write_killable() in dup_mmap()

2025-11-20T21:43:59Z

Allow waiting for the VMA write lock to be interrupted by fatal signals. The explicit check for fatal_signal_pending() can be removed as it is checked during vma_start_write_killable(). Improves the latency of killing the task as we do not wait for the reader to finish before checking for signals. Link: https://lkml.kernel.org/r/20251110203204.1454057-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Suren Baghdasaryan Reviewed-by: Liam R. Howlett Reviewed-by: Vlastimil Babka Reviewed-by: Lorenzo Stoakes Cc: Chris Li Cc: Jann Horn Cc: Shakeel Butt Signed-off-by: Andrew Morton

mm: kill mm_wr_locked from unmap_vmas() and unmap_single_vma()

2025-11-20T21:43:57Z

Kill mm_wr_locked since commit f8e97613fed2 ("mm: convert VM_PFNMAP tracking to pfnmap_track() + pfnmap_untrack()") remove the user. Link: https://lkml.kernel.org/r/20251104085709.2688433-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Lorenzo Stoakes Reviewed-by: Liam R. Howlett Acked-by: David Hildenbrand (Red Hat) Signed-off-by: Andrew Morton

mm: consistently use current->mm in mm_get_unmapped_area()

2025-11-17T01:27:57Z

mm_get_unmapped_area() is a wrapper around arch_get_unmapped_area() / arch_get_unmapped_area_topdown(), both of which search current->mm for some free space. Neither take an mm_struct - they implicitly operate on current->mm. But the wrapper takes an mm_struct and uses it to decide whether to search bottom up or top down. All callers pass in current->mm for this, so everything is working consistently. But it feels like an accident waiting to happen; eventually someone will call that function with a different mm, expecting to find free space in it, but what gets returned is free space in the current mm. So let's simplify by removing the parameter and have the wrapper use current->mm to decide which end to start at. Now everything is consistent and self-documenting. Link: https://lkml.kernel.org/r/20251003155306.2147572-1-ryan.roberts@arm.com Signed-off-by: Ryan Roberts Acked-by: David Hildenbrand Reviewed-by: Oscar Salvador Reviewed-by: Dev Jain Reviewed-by: Anshuman Khandual Reviewed-by: Lorenzo Stoakes Reviewed-by: Baolin Wang Cc: Liam Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: specify separate file and vm_file params in vm_area_desc

2025-09-23T03:17:11Z

Patch series "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()", v2. As part of the efforts to eliminate the problematic f_op->mmap callback, a new callback - f_op->mmap_prepare was provided. While we are converting these callbacks, we must deal with 'stacked' filesystems and drivers - those which in their own f_op->mmap callback invoke an inner f_op->mmap callback. To accomodate for this, a compatibility layer is provided that, via vfs_mmap(), detects if f_op->mmap_prepare is provided and if so, generates a vm_area_desc containing the VMA's metadata and invokes the call. So far, we have provided desc->file equal to vma->vm_file. However this is not necessarily valid, especially in the case of stacked drivers which wish to assign a new file after the inner hook is invoked. To account for this, we adjust vm_area_desc to have both file and vm_file fields. The .vm_file field is strictly set to vma->vm_file (or in the case of a new mapping, what will become vma->vm_file). However, .file is set to whichever file vfs_mmap() is invoked with when using the compatibilty layer. Therefore, if the VMA's file needs to be updated in .mmap_prepare, desc->vm_file should be assigned, whilst desc->file should be read. No current f_op->mmap_prepare users assign desc->file so this is safe to do. This makes the .mmap_prepare callback in the context of a stacked filesystem or driver completely consistent with the existing .mmap implementations. While we're here, we do a few small cleanups, and ensure that we const-ify things correctly in the vm_area_desc struct to avoid hooks accidentally trying to assign fields they should not. This patch (of 2): Stacked filesystems and drivers may invoke mmap hooks with a struct file pointer that differs from the overlying file. We will make this functionality possible in a subsequent patch. In order to prepare for this, let's update vm_area_struct to separately provide desc->file and desc->vm_file parameters. The desc->file parameter is the file that the hook is expected to operate upon, and is not assignable (though the hok may wish to e.g. update the file's accessed time for instance). The desc->vm_file defaults to what will become vma->vm_file and is what the hook must reassign should it wish to change the VMA"s vma->vm_file. For now we keep desc->file, vm_file the same to remain consistent. No f_op->mmap_prepare() callback sets a new vma->vm_file currently, so this is safe to change. While we're here, make the mm_struct desc->mm pointers at immutable as well as the desc->mm field itself. As part of this change, also update the single hook which this would otherwise break - mlock_future_ok(), invoked by secretmem_mmap_prepare()). We additionally update set_vma_from_desc() to compare fields in a more logical fashion, checking the (possibly) user-modified fields as the first operand against the existing value as the second one. Additionally, update VMA tests to accommodate changes. Link: https://lkml.kernel.org/r/cover.1756920635.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/3fa15a861bb7419f033d22970598aa61850ea267.1756920635.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Al Viro Cc: Christian Brauner Cc: David Hildenbrand Cc: Jan Kara Cc: Jann Horn Cc: Liam Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Pedro Falcato Signed-off-by: Andrew Morton

mm: convert core mm to mm_flags_*() accessors

2025-09-13T23:54:56Z

As part of the effort to move to mm->flags becoming a bitmap field, convert existing users to making use of the mm_flags_*() accessors which will, when the conversion is complete, be the only means of accessing mm_struct flags. This will result in the debug output being that of a bitmap output, which will result in a minor change here, but since this is for debug only, this should have no bearing. Otherwise, no functional changes intended. [akpm@linux-foundation.org: fix typo in comment]Link: https://lkml.kernel.org/r/1eb2266f4408798a55bda00cb04545a3203aa572.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Liam R. Howlett Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Baolin Wang Acked-by: David Hildenbrand Cc: Adrian Hunter Cc: Alexander Gordeev Cc: Alexander Shishkin Cc: Al Viro Cc: Andreas Larsson Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Barry Song Cc: Ben Segall Cc: Borislav Betkov Cc: Chengming Zhou Cc: Christian Borntraeger Cc: Christian Brauner Cc: David Rientjes Cc: David S. Miller Cc: Dev Jain Cc: Dietmar Eggemann Cc: Gerald Schaefer Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ian Rogers Cc: Ingo Molnar Cc: Jan Kara Cc: Jann Horn Cc: Jason Gunthorpe Cc: Jiri Olsa Cc: John Hubbard Cc: Juri Lelli Cc: Kan Liang Cc: Kees Cook Cc: Marc Rutland Cc: Mariano Pache Cc: "Masami Hiramatsu (Google)" Cc: Mateusz Guzik Cc: Matthew Wilcox (Oracle) Cc: Mel Gorman Cc: Michal Hocko Cc: Namhyung kim Cc: Oleg Nesterov Cc: Peter Xu Cc: Peter Zijlstra Cc: Ryan Roberts Cc: Shakeel Butt Cc: Steven Rostedt Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Thomas Gleinxer Cc: Valentin Schneider Cc: Vasily Gorbik Cc: Vincent Guittot Cc: Vlastimil Babka Cc: xu xin Cc: Zi Yan Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-07-31T21:57:54Z

Pull MM updates from Andrew Morton: "As usual, many cleanups. The below blurbiage describes 42 patchsets. 21 of those are partially or fully cleanup work. "cleans up", "cleanup", "maintainability", "rationalizes", etc. I never knew the MM code was so dirty. "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes) addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly mapped VMAs were not eligible for merging with existing adjacent VMAs. "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park) adds a new kernel module which simplifies the setup and usage of DAMON in production environments. "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig) is a cleanup to the writeback code which removes a couple of pointers from struct writeback_control. "drivers/base/node.c: optimization and cleanups" (Donet Tom) contains largely uncorrelated cleanups to the NUMA node setup and management code. "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman) does some maintenance work on the userfaultfd code. "Readahead tweaks for larger folios" (Ryan Roberts) implements some tuneups for pagecache readahead when it is reading into order>0 folios. "selftests/mm: Tweaks to the cow test" (Mark Brown) provides some cleanups and consistency improvements to the selftests code. "Optimize mremap() for large folios" (Dev Jain) does that. A 37% reduction in execution time was measured in a memset+mremap+munmap microbenchmark. "Remove zero_user()" (Matthew Wilcox) expunges zero_user() in favor of the more modern memzero_page(). "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand) addresses some warts which David noticed in the huge page code. These were not known to be causing any issues at this time. "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park) provides some cleanup and consolidation work in DAMON. "use vm_flags_t consistently" (Lorenzo Stoakes) uses vm_flags_t in places where we were inappropriately using other types. "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy) increases the reliability of large page allocation in the memfd code. "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple) removes several now-unneeded PFN_* flags. "mm/damon: decouple sysfs from core" (SeongJae Park) implememnts some cleanup and maintainability work in the DAMON sysfs layer. "madvise cleanup" (Lorenzo Stoakes) does quite a lot of cleanup/maintenance work in the madvise() code. "madvise anon_name cleanups" (Vlastimil Babka) provides additional cleanups on top or Lorenzo's effort. "Implement numa node notifier" (Oscar Salvador) creates a standalone notifier for NUMA node memory state changes. Previously these were lumped under the more general memory on/offline notifier. "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan) cleans up the pageblock isolation code and fixes a potential issue which doesn't seem to cause any problems in practice. "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park) adds additional drgn- and python-based DAMON selftests which are more comprehensive than the existing selftest suite. "Misc rework on hugetlb faulting path" (Oscar Salvador) fixes a rather obscure deadlock in the hugetlb fault code and follows that fix with a series of cleanups. "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport) rationalizes and cleans up the highmem-specific code in the CMA allocator. "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand) provides cleanups and future-preparedness to the migration code. "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park) adds some tracepoints to some DAMON auto-tuning code. "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park) does that. "mm/damon: misc cleanups" (SeongJae Park) also does what it claims. "mm: folio_pte_batch() improvements" (David Hildenbrand) cleans up the large folio PTE batching code. "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park) facilitates dynamic alteration of DAMON's inter-node allocation policy. "Remove unmap_and_put_page()" (Vishal Moola) provides a couple of page->folio conversions. "mm: per-node proactive reclaim" (Davidlohr Bueso) implements a per-node control of proactive reclaim - beyond the current memcg-based implementation. "mm/damon: remove damon_callback" (SeongJae Park) replaces the damon_callback interface with a more general and powerful damon_call()+damos_walk() interface. "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes) implements a number of mremap cleanups (of course) in preparation for adding new mremap() functionality: newly permit the remapping of multiple VMAs when the user is specifying MREMAP_FIXED. It still excludes some specialized situations where this cannot be performed reliably. "drop hugetlb_free_pgd_range()" (Anthony Yznaga) switches some sparc hugetlb code over to the generic version and removes the thus-unneeded hugetlb_free_pgd_range(). "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park) augments the present userspace-requested update of DAMON sysfs monitoring files. Automatic update is now provided, along with a tunable to control the update interval. "Some randome fixes and cleanups to swapfile" (Kemeng Shi) does what is claims. "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand) provides (and uses) a means by which debug-style functions can grab a copy of a pageframe and inspect it locklessly without tripping over the races inherent in operating on the live pageframe directly. "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan) addresses the large contention issues which can be triggered by reads from that procfs file. Latencies are reduced by more than half in some situations. The series also introduces several new selftests for the /proc/pid/maps interface. "__folio_split() clean up" (Zi Yan) cleans up __folio_split()! "Optimize mprotect() for large folios" (Dev Jain) provides some quite large (>3x) speedups to mprotect() when dealing with large folios. "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian) does some cleanup work in the selftests code. "tools/testing: expand mremap testing" (Lorenzo Stoakes) extends the mremap() selftest in several ways, including adding more checking of Lorenzo's recently added "permit mremap() move of multiple VMAs" feature. "selftests/damon/sysfs.py: test all parameters" (SeongJae Park) extends the DAMON sysfs interface selftest so that it tests all possible user-requested parameters. Rather than the present minimal subset" * tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits) MAINTAINERS: add missing headers to mempory policy & migration section MAINTAINERS: add missing file to cgroup section MAINTAINERS: add MM MISC section, add missing files to MISC and CORE MAINTAINERS: add missing zsmalloc file MAINTAINERS: add missing files to page alloc section MAINTAINERS: add missing shrinker files MAINTAINERS: move memremap.[ch] to hotplug section MAINTAINERS: add missing mm_slot.h file THP section MAINTAINERS: add missing interval_tree.c to memory mapping section MAINTAINERS: add missing percpu-internal.h file to per-cpu section mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info() selftests/damon: introduce _common.sh to host shared function selftests/damon/sysfs.py: test runtime reduction of DAMON parameters selftests/damon/sysfs.py: test non-default parameters runtime commit selftests/damon/sysfs.py: generalize DAMON context commit assertion selftests/damon/sysfs.py: generalize monitoring attributes commit assertion selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion selftests/damon/sysfs.py: test DAMOS filters commitment selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion selftests/damon/sysfs.py: test DAMOS destinations commitment ...

mm: simplify min_brk handling in brk()

2025-07-20T01:59:53Z

Set min_brk to mm->start_brk by default, and override it with mm->end_data only when CONFIG_COMPAT_BRK is enabled and brk_randomized is false. This makes the logic clearer with no functional change. Link: https://lkml.kernel.org/r/20250710025859.926355-1-liuqiye2025@163.com Signed-off-by: Xuanye Liu Reviewed-by: Pedro Falcato Reviewed-by: Lorenzo Stoakes Cc: Jann Horn Cc: Liam Howlett Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: deduplicate mm_get_unmapped_area()

2025-07-13T23:38:19Z

Essentially it sets vm_flags==0 for mm_get_unmapped_area_vmflags(). Use the helper instead to dedup the lines. Link: https://lkml.kernel.org/r/20250627160739.2124768-1-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: Jason Gunthorpe Reviewed-by: Oscar Salvador Reviewed-by: Zi Yan Reviewed-by: Lorenzo Stoakes Reviewed-by: Pedro Falcato Acked-by: David Hildenbrand Reviewed-by: Dev Jain Reviewed-by: Anshuman Khandual Cc: "Liam R. Howlett" Cc: Vlastimil Babka Cc: Jann Horn Cc: Huacai Chen Cc: Muchun Song Cc: Thomas Bogendoerfer Signed-off-by: Andrew Morton

mm: update core kernel code to use vm_flags_t consistently

2025-07-10T05:42:13Z

The core kernel code is currently very inconsistent in its use of vm_flags_t vs. unsigned long. This prevents us from changing the type of vm_flags_t in the future and is simply not correct, so correct this. While this results in rather a lot of churn, it is a critical pre-requisite for a future planned change to VMA flag type. Additionally, update VMA userland tests to account for the changes. To make review easier and to break things into smaller parts, driver and architecture-specific changes is left for a subsequent commit. The code has been adjusted to cascade the changes across all calling code as far as is needed. We will adjust architecture-specific and driver code in a subsequent patch. Overall, this patch does not introduce any functional change. Link: https://lkml.kernel.org/r/d1588e7bb96d1ea3fe7b9df2c699d5b4592d901d.1750274467.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Acked-by: Kees Cook Acked-by: Mike Rapoport (Microsoft) Acked-by: Jan Kara Acked-by: Christian Brauner Reviewed-by: Vlastimil Babka Acked-by: Oscar Salvador Reviewed-by: Pedro Falcato Acked-by: Zi Yan Acked-by: David Hildenbrand Reviewed-by: Anshuman Khandual Cc: Jann Horn Cc: Liam R. Howlett Cc: Catalin Marinas Cc: Jarkko Sakkinen Signed-off-by: Andrew Morton