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Patch series "Simplify the page flags a little".
In the course of our folio conversions, we have made many page flags only
used on folios, so we can now remove the page-based accessors. This
should cut down compile time a little, and prevent new users from cropping
up.
There is more that could be done in this area, but it would produce merge
conflicts, so I'll sit on those patches until next merge window. We now
have line of sight to removing PG_private_2 and PG_private.
This patch (of 10):
This flag is now only used on folios, so we can remove all the page
accessors.
[akpm@linux-foundation.org: fix arch/powerpc/mm/pgtable-frag.c]
Link: https://lkml.kernel.org/r/20240821193445.2294269-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240821193445.2294269-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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By using a few values in the top byte, users of page_type can store up to
24 bits of additional data in page_type. It also reduces the code size as
(with replacement of READ_ONCE() with data_race()), the kernel can check
just a single byte. eg:
ffffffff811e3a79: 8b 47 30 mov 0x30(%rdi),%eax
ffffffff811e3a7c: 55 push %rbp
ffffffff811e3a7d: 48 89 e5 mov %rsp,%rbp
ffffffff811e3a80: 25 00 00 00 82 and $0x82000000,%eax
ffffffff811e3a85: 3d 00 00 00 80 cmp $0x80000000,%eax
ffffffff811e3a8a: 74 4d je ffffffff811e3ad9 <folio_mapping+0x69>
becomes:
ffffffff811e3a69: 80 7f 33 f5 cmpb $0xf5,0x33(%rdi)
ffffffff811e3a6d: 55 push %rbp
ffffffff811e3a6e: 48 89 e5 mov %rsp,%rbp
ffffffff811e3a71: 74 4d je ffffffff811e3ac0 <folio_mapping+0x60>
replacing three instructions with one.
[wangkefeng.wang@huawei.com: fix ubsan warnings]
Link: https://lkml.kernel.org/r/2d19c48a-c550-4345-bf36-d05cd303c5de@huawei.com
Link: https://lkml.kernel.org/r/20240821173914.2270383-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Resolve the awkward "and add one to this opaque constant" test into a
self-documenting inline function.
Link: https://lkml.kernel.org/r/20240821173914.2270383-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We already force-inline page_fixed_fake_head(), page_is_fake_head() and
PageTail(), however the compiler might decide that _compound_head() is not
worthy to be inlined, because of page_fixed_fake_head().
The result is that, for example, PageAnonExclusive() now might involve a
function call when checking PageHuge(), which performs a
page_folio()->_compound_head() call. This can lead to a slight regression
of the stress-ng.clone benchmark.
This is not super-urgent to fix, but always inlining _compound_head()
seems like the obvious thing to do for this primitive, similar to the
other ones.
This change restores the slight regression and a compilation with
CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP=y shows no relevant bloat [2]:
add/remove: 15/14 grow/shrink: 79/87 up/down: 12836/-13917 (-1081)
...
Total: Before=32786363, After=32785282, chg -0.00%
[1] https://lkml.kernel.org/r/817150f2-abf7-430f-9973-540bd6cdd26f@intel.com
[2] https://lore.kernel.org/all/116e117c-2821-401d-8e62-b85cdec37f4a@redhat.com/
Link: https://lkml.kernel.org/r/20240820122210.660140-1-david@redhat.com
Fixes: c0bff412e67b ("mm: allow anon exclusive check over hugetlb tail pages")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202407301049.5051dc19-oliver.sang@intel.com
Tested-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The new page type allows physical memory scanners to detect unaccepted
memory and handle it accordingly.
The page type is serialized with zone lock.
Link: https://lkml.kernel.org/r/20240809114854.3745464-5-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The PG_error bit is now unused; delete it and free up a bit in
page->flags.
Link: https://lkml.kernel.org/r/20240807193528.1865100-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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KCSAN complains about possible data races: while we check for a page_type
-- for example for sanity checks -- we might concurrently modify the
mapcount that overlays page_type.
Let's use READ_ONCE to avoid load tearing (shouldn't make a difference)
and to make KCSAN happy.
Likely, we might also want to use WRITE_ONCE for the writer side of
page_type, if KCSAN ever complains about that. But we'll not mess with
that for now.
Note: nothing should really be broken besides wrong KCSAN complaints. The
sanity check that triggers this was added in commit 68f0320824fa
("mm/rmap: convert folio_add_file_rmap_range() into
folio_add_file_rmap_[pte|ptes|pmd]()"). Even before that similar races
likely where possible, ever since we added page_type in commit
6e292b9be7f4 ("mm: split page_type out from _mapcount").
Link: https://lkml.kernel.org/r/20240531125616.2850153-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202405281431.c46a3be9-lkp@intel.com
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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when offlining
We currently have a hack for virtio-mem in place to handle memory
offlining with PageOffline pages for which we already adjusted the managed
page count.
Let's enlighten memory offlining code so we can get rid of that hack, and
document the situation.
Link: https://lkml.kernel.org/r/20240607090939.89524-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Marco Elver <elver@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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instead of PageReserved()
We currently initialize the memmap such that PG_reserved is set and the
refcount of the page is 1. In virtio-mem code, we have to manually clear
that PG_reserved flag to make memory offlining with partially hotplugged
memory blocks possible: has_unmovable_pages() would otherwise bail out on
such pages.
We want to avoid PG_reserved where possible and move to typed pages
instead. Further, we want to further enlighten memory offlining code
about PG_offline: offline pages in an online memory section. One example
is handling managed page count adjustments in a cleaner way during memory
offlining.
So let's initialize the pages with PG_offline instead of PG_reserved.
generic_online_page()->__free_pages_core() will now clear that flag before
handing that memory to the buddy.
Note that the page refcount is still 1 and would forbid offlining of such
memory except when special care is take during GOING_OFFLINE as currently
only implemented by virtio-mem.
With this change, we can now get non-PageReserved() pages in the XEN
balloon list. From what I can tell, that can already happen via
decrease_reservation(), so that should be fine.
HV-balloon should not really observe a change: partial online memory
blocks still cannot get surprise-offlined, because the refcount of these
PageOffline() pages is 1.
Update virtio-mem, HV-balloon and XEN-balloon code to be aware that
hotplugged pages are now PageOffline() instead of PageReserved() before
they are handed over to the buddy.
We'll leave the ZONE_DEVICE case alone for now.
Note that self-hosted vmemmap pages will no longer be marked as
reserved. This matches ordinary vmemmap pages allocated from the buddy
during memory hotplug. Now, really only vmemmap pages allocated from
memblock during early boot will be marked reserved. Existing
PageReserved() checks seem to be handling all relevant cases correctly
even after this change.
Link: https://lkml.kernel.org/r/20240607090939.89524-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Oscar Salvador <osalvador@suse.de> [generic memory-hotplug bits]
Cc: Alexander Potapenko <glider@google.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Marco Elver <elver@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Let's clean it up: use a proper page type and store our data (offset into
a page) in the lower 16 bit as documented.
We won't be able to support 256 KiB base pages, which is acceptable.
Teach Kconfig to handle that cleanly using a new CONFIG_HAVE_ZSMALLOC.
Based on this, we should do a proper "struct zsdesc" conversion, as
proposed in [1].
This removes the last _mapcount/page_type offender.
[1] https://lore.kernel.org/all/20231130101242.2590384-1-42.hyeyoo@gmail.com/
Link: https://lkml.kernel.org/r/20240529111904.2069608-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Tested-by: Sergey Senozhatsky <senozhatsky@chromium.org> [zram/zsmalloc workloads]
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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As long as the owner sets a page type first, we can allow reuse of the
lower 16 bit: sufficient to store an offset into a 64 KiB page, which is
the maximum base page size in *common* configurations (ignoring the 256
KiB variant). Restrict it to the head page.
We'll use that for zsmalloc next, to set a proper type while still reusing
that field to store information (offset into a base page) that cannot go
elsewhere for now.
Let's reserve the lower 16 bit for that purpose and for catching mapcount
underflows, and let's reduce PAGE_TYPE_BASE to a single bit.
Note that we will still have to overflow the mapcount quite a lot until we
would actually indicate a valid page type.
Start handing out the type bits from highest to lowest, to make it clearer
how many bits for types we have left. Out of 15 bit we can use for types,
we currently use 6. If we run out of bits before we have better typing
(e.g., memdesc), we can always investigate storing a value instead [1].
[1] https://lore.kernel.org/all/00ba1dff-7c05-46e8-b0d9-a78ac1cfc198@redhat.com/
[akpm@linux-foundation.org: fix PG_hugetlb typo, per David]
Link: https://lkml.kernel.org/r/20240529111904.2069608-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Tested-by: Sergey Senozhatsky <senozhatsky@chromium.org> [zram/zsmalloc workloads]
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There are some functions only used inside mm. Move them into internal.h.
No functional change intended.
Link: https://lkml.kernel.org/r/20240612071835.157004-11-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202405251049.hxjwX7zO-lkp@intel.com/
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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All callers are now converted, delete this compatibility wrapper. Also
fix up some comments which referred to page_mapping.
Link: https://lkml.kernel.org/r/20240423225552.4113447-7-willy@infradead.org
Link: https://lkml.kernel.org/r/20240524181813.698813-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Changing PG_slab from a page flag to a page type in commit 46df8e73a4a3
("mm: free up PG_slab") in has the unintended consequence of removing the
PG_slab constant from kernel debuginfo. The commit does add the value to
the vmcoreinfo note, which allows debuggers to find the value without
hardcoding it. However it's most flexible to continue representing the
constant with an enum. To that end, convert the page type fields into an
enum. Debuggers will now be able to detect that PG_slab's type has
changed from enum pageflags to enum pagetype.
Link: https://lkml.kernel.org/r/20240607202954.1198180-1-stephen.s.brennan@oracle.com
Fixes: 46df8e73a4a3 ("mm: free up PG_slab")
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hao Ge <gehao@kylinos.cn>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Omar Sandoval <osandov@osandov.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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All callers now use folio_*_referenced() so we can remove the
PageReferenced family of functions.
Link: https://lkml.kernel.org/r/20240424191914.361554-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Make PageUptodate return bool to align the return values of
folio_test_uptodate function
Link: https://lkml.kernel.org/r/20240422032725.41452-1-gehao@kylinos.cn
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Cc: David Hildenbrand <david@redhat.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ruihan Li <lrh2000@pku.edu.cn>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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If CONFIG_PAGE_IDLE_FLAG is not set, we can use FOLIO_FLAG_FALSE() to
generate these definitions.
Link: https://lkml.kernel.org/r/20240402201252.917342-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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PageAnonExclusive() used to forbid tail pages for hugetlbfs, as that used
to be called mostly in hugetlb specific paths and the head page was
guaranteed.
As we move forward towards merging hugetlb paths into generic mm, we may
start to pass in tail hugetlb pages (when with cont-pte/cont-pmd huge
pages) for such check. Allow it to properly fetch the head, in which case
the anon-exclusiveness of the head will always represents the tail page.
There's already a sign of it when we look at the GUP-fast which already
contain the hugetlb processing altogether: we used to have a specific
commit 5805192c7b72 ("mm/gup: handle cont-PTE hugetlb pages correctly in
gup_must_unshare() via GUP-fast") covering that area. Now with this more
generic change, that can also go away.
[akpm@linux-foundation.org: simplify PageAnonExclusive(), per Matthew]
Link: https://lkml.kernel.org/r/Zg3u5Sh9EbbYPhaI@casper.infradead.org
Link: https://lkml.kernel.org/r/20240403013249.1418299-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Reduce the usage of PageFlag tests and reduce the number of
compound_head() calls.
For multi-page folios, we'll now show all pages as having the flags that
apply to them, e.g. if it's dirty, all pages will have the dirty flag set
instead of just the head page. The mapped flag is still per page, as is
the hwpoison flag.
[willy@infradead.org: fix up some bits vs masks]
Link: https://lkml.kernel.org/r/20240403173112.1450721-1-willy@infradead.org
[willy@infradead.org: fix warnings]
Link: https://lkml.kernel.org/r/ZhBPtCYfSuFuUMEz@casper.infradead.org
Link: https://lkml.kernel.org/r/20240326171045.410737-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Svetly Todorov <svetly.todorov@memverge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This function does not modify its argument; let the callers know that so
they can make better optimisation decisions.
Link: https://lkml.kernel.org/r/20240326171045.410737-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Make PageMappingFlags() return bool like folio_mapping_flags().
Link: https://lkml.kernel.org/r/20240321030712.80618-1-gehao@kylinos.cn
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Make __PageMovable() return bool like __folio_test_movable().
Link: https://lkml.kernel.org/r/20240321032256.82063-1-gehao@kylinos.cn
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Reclaim the Slab page flag by using a spare bit in PageType. We are
perennially short of page flags for various purposes, and now that the
original SLAB allocator has been retired, SLUB does not use the
mapcount/page_type field. This lets us remove a number of special cases
for ignoring mapcount on Slab pages.
[willy@infradead.org: update vmcoreinfo]
Link: https://lkml.kernel.org/r/ZgGV-O8WYQ_83kxp@casper.infradead.org
Link: https://lkml.kernel.org/r/20240321142448.1645400-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We can call it only once instead of twice.
Link: https://lkml.kernel.org/r/20240321142448.1645400-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now that prep_compound_page() initialises folio->_deferred_list,
folio_prep_large_rmappable()'s only purpose is to set the large_rmappable
flag, so inline it into the two callers. Take the opportunity to convert
the large_rmappable definition from PAGEFLAG to FOLIO_FLAG and remove the
existance of PageTestLargeRmappable and friends.
Link: https://lkml.kernel.org/r/20240321142448.1645400-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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|
The current folio_test_hugetlb() can be fooled by a concurrent folio split
into returning true for a folio which has never belonged to hugetlbfs.
This can't happen if the caller holds a refcount on it, but we have a few
places (memory-failure, compaction, procfs) which do not and should not
take a speculative reference.
Since hugetlb pages do not use individual page mapcounts (they are always
fully mapped and use the entire_mapcount field to record the number of
mappings), the PageType field is available now that page_mapcount()
ignores the value in this field.
In compaction and with CONFIG_DEBUG_VM enabled, the current implementation
can result in an oops, as reported by Luis. This happens since 9c5ccf2db04b
("mm: remove HUGETLB_PAGE_DTOR") effectively added some VM_BUG_ON() checks
in the PageHuge() testing path.
[willy@infradead.org: update vmcoreinfo]
Link: https://lkml.kernel.org/r/ZgGZUvsdhaT1Va-T@casper.infradead.org
Link: https://lkml.kernel.org/r/20240321142448.1645400-6-willy@infradead.org
Fixes: 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Luis Chamberlain <mcgrof@kernel.org>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218227
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Return 0 for pages which can't be mapped. This matches how page_mapped()
works. It is more convenient for users to not have to filter out these
pages.
Link: https://lkml.kernel.org/r/20240321142448.1645400-5-willy@infradead.org
Fixes: 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Following the separation of FOLIO_FLAGS from PAGEFLAGS, separate
FOLIO_FLAG_FALSE from PAGEFLAG_FALSE and FOLIO_TYPE_OPS from
PAGE_TYPE_OPS.
Link: https://lkml.kernel.org/r/20240321142448.1645400-3-willy@infradead.org
Fixes: 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Constify the flag tests that aren't automatically generated and the tests
that look like flag tests but are more complicated.
Link: https://lkml.kernel.org/r/20240227192337.757313-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Now that dump_page() takes a const argument, we can constify all the page
flag tests.
Link: https://lkml.kernel.org/r/20240227192337.757313-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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All callers have been converted to use folios, so remove the various
set/clear/test functions defined on pages.
Link: https://lkml.kernel.org/r/20240227192337.757313-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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All callers have been converted to use folios. This was the only user of
PF_ONLY_HEAD, so remove that too.
Link: https://lkml.kernel.org/r/20240227192337.757313-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Patch series "PageFlags cleanups".
We have now successfully removed all of the uses of some of the PageFlags
from the kernel, but there's nothing to stop somebody reintroducing them.
By splitting out FOLIO_FLAGS from PAGEFLAGS, we can stop defining the old
flags; and we do that in some of the later patches.
After doing this, I realised that dump_page() was living dangerously; we
could end up calling folio_test_foo() on a pointer which no longer pointed
to a folio (as dump_page() is not necessarily called when the caller has a
reference to the page). So I fixed that up.
And then I realised that this was the key to making dump_page() take a
const argument, which means we can constify the page flags testing, which
means we can remove more cast-away-the-const bad code.
And here's where I ended up.
This patch (of 8):
We've progressed far enough with the folio transition that some flags are
now no longer checked on pages, but only on folios. To prevent new users
appearing, prepare to only define the folio versions of the flag
test/set/clear.
Link: https://lkml.kernel.org/r/20240227192337.757313-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240227192337.757313-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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|
Nobody now checks the return value from any of these functions, so
add an assertion at the beginning of the function and return void.
Link: https://lkml.kernel.org/r/20231108204605.745109-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Patch series "Make folio_start_writeback return void".
Most of the folio flag-setting functions return void.
folio_start_writeback is gratuitously different; the only two filesystems
that do anything with the return value emit debug messages if it's already
set, and we can (and should) do that internally without bothering the
filesystem to do it.
This patch (of 4):
There are no more callers of this wrapper.
Link: https://lkml.kernel.org/r/20231108204605.745109-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20231108204605.745109-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
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) <willy@infradead.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This function is misleading; people think it means "Is this a THP", when
all it actually does is check whether this is a large folio. Remove it;
the one remaining user should have been checking to see whether the folio
is PMD sized or not.
Link: https://lkml.kernel.org/r/20230816151201.3655946-12-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Store the folio order in the low byte of the flags word in the first tail
page. This frees up the word that was being used to store the order and
dtor bytes previously.
Link: https://lkml.kernel.org/r/20230816151201.3655946-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Move PG_writeback into bottom byte so that it can use PG_waiters in a
later patch. Move PG_head into bottom byte as well to match with where
'order' is moving next. PG_active and PG_workingset move into the second
byte to make room for them.
By putting PG_head in bit 6, we ensure that it is cleared by assigning the
folio order to the bottom byte of the first tail page (since the order
cannot be larger than 63).
Link: https://lkml.kernel.org/r/20230816151201.3655946-10-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Stored in the first tail page's flags, this flag replaces the destructor.
That removes the last of the destructors, so remove all references to
folio_dtor and compound_dtor.
Link: https://lkml.kernel.org/r/20230816151201.3655946-9-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We can use a bit in page[1].flags to indicate that this folio belongs to
hugetlb instead of using a value in page[1].dtors. That lets
folio_test_hugetlb() become an inline function like it should be. We can
also get rid of NULL_COMPOUND_DTOR.
Link: https://lkml.kernel.org/r/20230816151201.3655946-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Split ptdesc from struct page", v9.
The MM subsystem is trying to shrink struct page. This patchset
introduces a memory descriptor for page table tracking - struct ptdesc.
This patchset introduces ptdesc, splits ptdesc from struct page, and
converts many callers of page table constructor/destructors to use
ptdescs.
Ptdesc is a foundation to further standardize page tables, and eventually
allow for dynamic allocation of page tables independent of struct page.
However, the use of pages for page table tracking is quite deeply
ingrained and varied across archictectures, so there is still a lot of
work to be done before that can happen.
This patch (of 31):
No folio equivalents for page type operations have been defined, so define
them for later folio conversions.
Also changes the Page##uname macros to take in const struct page* since we
only read the memory here.
Link: https://lkml.kernel.org/r/20230807230513.102486-1-vishal.moola@gmail.com
Link: https://lkml.kernel.org/r/20230807230513.102486-2-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guo Ren <guoren@kernel.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The current uses of PageAnon in page table check functions can lead to
type confusion bugs between struct page and slab [1], if slab pages are
accidentally mapped into the user space. This is because slab reuses the
bits in struct page to store its internal states, which renders PageAnon
ineffective on slab pages.
Since slab pages are not expected to be mapped into the user space, this
patch adds BUG_ON(PageSlab(page)) checks to make sure that slab pages
are not inadvertently mapped. Otherwise, there must be some bugs in the
kernel.
Reported-by: syzbot+fcf1a817ceb50935ce99@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/000000000000258e5e05fae79fc1@google.com/ [1]
Fixes: df4e817b7108 ("mm: page table check")
Cc: <stable@vger.kernel.org> # 5.17
Signed-off-by: Ruihan Li <lrh2000@pku.edu.cn>
Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/r/20230515130958.32471-5-lrh2000@pku.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
switching from a user process to a kernel thread.
- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
Raghav.
- zsmalloc performance improvements from Sergey Senozhatsky.
- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.
- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page()
- make __filemap_get_folio()'s return value more useful
- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.
- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.
- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).
- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.
- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
rather than exclusive, and has fixed a bunch of errors which were
caused by its unintuitive meaning.
- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.
- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.
- Cleanups to do_fault_around() by Lorenzo Stoakes.
- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.
- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.
- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.
- Lorenzo has also contributed further cleanups of vma_merge().
- Chaitanya Prakash provides some fixes to the mmap selftesting code.
- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.
- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.
- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.
- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.
- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.
- Yosry Ahmed has improved the performance of memcg statistics
flushing.
- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.
- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.
- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.
- Pankaj Raghav has made page_endio() unneeded and has removed it.
- Peter Xu contributed some rationalizations of the userfaultfd
selftests.
- Yosry Ahmed has fixed an issue around memcg's page recalim
accounting.
- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.
- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.
- Peter Xu fixes a few issues with uffd-wp at fork() time.
- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.
* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
shmem: restrict noswap option to initial user namespace
mm/khugepaged: fix conflicting mods to collapse_file()
sparse: remove unnecessary 0 values from rc
mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
maple_tree: fix allocation in mas_sparse_area()
mm: do not increment pgfault stats when page fault handler retries
zsmalloc: allow only one active pool compaction context
selftests/mm: add new selftests for KSM
mm: add new KSM process and sysfs knobs
mm: add new api to enable ksm per process
mm: shrinkers: fix debugfs file permissions
mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
migrate_pages_batch: fix statistics for longterm pin retry
userfaultfd: use helper function range_in_vma()
lib/show_mem.c: use for_each_populated_zone() simplify code
mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
fs/buffer: convert create_page_buffers to folio_create_buffers
fs/buffer: add folio_create_empty_buffers helper
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"There are a number of major cleanups in ext4 this cycle:
- The data=journal writepath has been significantly cleaned up and
simplified, and reduces a large number of data=journal special
cases by Jan Kara.
- Ojaswin Muhoo has replaced linked list used to track extents that
have been used for inode preallocation with a red-black tree in the
multi-block allocator. This improves performance for workloads
which do a large number of random allocating writes.
- Thanks to Kemeng Shi for a lot of cleanup and bug fixes in the
multi-block allocator.
- Matthew wilcox has converted the code paths for reading and writing
ext4 pages to use folios.
- Jason Yan has continued to factor out ext4_fill_super() into
smaller functions for improve ease of maintenance and
comprehension.
- Josh Triplett has created an uapi header for ext4 userspace API's"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (105 commits)
ext4: Add a uapi header for ext4 userspace APIs
ext4: remove useless conditional branch code
ext4: remove unneeded check of nr_to_submit
ext4: move dax and encrypt checking into ext4_check_feature_compatibility()
ext4: factor out ext4_block_group_meta_init()
ext4: move s_reserved_gdt_blocks and addressable checking into ext4_check_geometry()
ext4: rename two functions with 'check'
ext4: factor out ext4_flex_groups_free()
ext4: use ext4_group_desc_free() in ext4_put_super() to save some duplicated code
ext4: factor out ext4_percpu_param_init() and ext4_percpu_param_destroy()
ext4: factor out ext4_hash_info_init()
Revert "ext4: Fix warnings when freezing filesystem with journaled data"
ext4: Update comment in mpage_prepare_extent_to_map()
ext4: Simplify handling of journalled data in ext4_bmap()
ext4: Drop special handling of journalled data from ext4_quota_on()
ext4: Drop special handling of journalled data from ext4_evict_inode()
ext4: Fix special handling of journalled data from extent zeroing
ext4: Drop special handling of journalled data from extent shifting operations
ext4: Drop special handling of journalled data from ext4_sync_file()
ext4: Commit transaction before writing back pages in data=journal mode
...
|
|
Sidhartha Kumar removed the last caller of PageHeadHuge(), so we can now
remove it and make folio_test_hugetlb() the real implementation. Add
kernel-doc for folio_test_hugetlb().
Link: https://lkml.kernel.org/r/20230327151050.1787744-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Remove several calls to compound_head() and the last caller of
set_page_writeback_keepwrite(), so remove the wrapper too.
Also export bio_add_folio() as this is the first caller from a module.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20230324180129.1220691-4-willy@infradead.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
|
|
With SLOB removed we no longer need the PG_slob_free alias for
PG_private. Also update tools/mm/page-types.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Acked-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
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Code inspection reveals that PG_skip_kasan_poison is redundant with
kasantag, because the former is intended to be set iff the latter is the
match-all tag. It can also be observed that it's basically pointless to
poison pages which have kasantag=0, because any pages with this tag would
have been pointed to by pointers with match-all tags, so poisoning the
pages would have little to no effect in terms of bug detection.
Therefore, change the condition in should_skip_kasan_poison() to check
kasantag instead, and remove PG_skip_kasan_poison and associated flags.
Link: https://lkml.kernel.org/r/20230310042914.3805818-3-pcc@google.com
Link: https://linux-review.googlesource.com/id/I57f825f2eaeaf7e8389d6cf4597c8a5821359838
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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%pGp format is used to display 'flags' field of a struct page. However,
some page flags (i.e. PG_buddy, see page-flags.h for more details) are
stored in page_type field. To display human-readable output of page_type,
introduce %pGt format.
It is important to note the meaning of bits are different in page_type.
if page_type is 0xffffffff, no flags are set. Setting PG_buddy
(0x00000080) flag results in a page_type of 0xffffff7f. Clearing a bit
actually means setting a flag. Bits in page_type are inverted when
displaying type names.
Only values for which page_type_has_type() returns true are considered as
page_type, to avoid confusion with mapcount values. if it returns false,
only raw values are displayed and not page type names.
Link: https://lkml.kernel.org/r/20230130042514.2418-3-42.hyeyoo@gmail.com
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com> [vsprintf part]
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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