979 Commits

Author SHA1 Message Date
Linus Torvalds
eb0ece1602 - The 6 patch series "Enable strict percpu address space checks" from
Uros Bizjak uses x86 named address space qualifiers to provide
   compile-time checking of percpu area accesses.
 
   This has caused a small amount of fallout - two or three issues were
   reported.  In all cases the calling code was founf to be incorrect.
 
 - The 4 patch series "Some cleanup for memcg" from Chen Ridong
   implements some relatively monir cleanups for the memcontrol code.
 
 - The 17 patch series "mm: fixes for device-exclusive entries (hmm)"
   from David Hildenbrand fixes a boatload of issues which David found then
   using device-exclusive PTE entries when THP is enabled.  More work is
   needed, but this makes thins better - our own HMM selftests now succeed.
 
 - The 2 patch series "mm: zswap: remove z3fold and zbud" from Yosry
   Ahmed remove the z3fold and zbud implementations.  They have been
   deprecated for half a year and nobody has complained.
 
 - The 5 patch series "mm: further simplify VMA merge operation" from
   Lorenzo Stoakes implements numerous simplifications in this area.  No
   runtime effects are anticipated.
 
 - The 4 patch series "mm/madvise: remove redundant mmap_lock operations
   from process_madvise()" from SeongJae Park rationalizes the locking in
   the madvise() implementation.  Performance gains of 20-25% were observed
   in one MADV_DONTNEED microbenchmark.
 
 - The 12 patch series "Tiny cleanup and improvements about SWAP code"
   from Baoquan He contains a number of touchups to issues which Baoquan
   noticed when working on the swap code.
 
 - The 2 patch series "mm: kmemleak: Usability improvements" from Catalin
   Marinas implements a couple of improvements to the kmemleak user-visible
   output.
 
 - The 2 patch series "mm/damon/paddr: fix large folios access and
   schemes handling" from Usama Arif provides a couple of fixes for DAMON's
   handling of large folios.
 
 - The 3 patch series "mm/damon/core: fix wrong and/or useless
   damos_walk() behaviors" from SeongJae Park fixes a few issues with the
   accuracy of kdamond's walking of DAMON regions.
 
 - The 3 patch series "expose mapping wrprotect, fix fb_defio use" from
   Lorenzo Stoakes changes the interaction between framebuffer deferred-io
   and core MM.  No functional changes are anticipated - this is
   preparatory work for the future removal of page structure fields.
 
 - The 4 patch series "mm/damon: add support for hugepage_size DAMOS
   filter" from Usama Arif adds a DAMOS filter which permits the filtering
   by huge page sizes.
 
 - The 4 patch series "mm: permit guard regions for file-backed/shmem
   mappings" from Lorenzo Stoakes extends the guard region feature from its
   present "anon mappings only" state.  The feature now covers shmem and
   file-backed mappings.
 
 - The 4 patch series "mm: batched unmap lazyfree large folios during
   reclamation" from Barry Song cleans up and speeds up the unmapping for
   pte-mapped large folios.
 
 - The 18 patch series "reimplement per-vma lock as a refcount" from
   Suren Baghdasaryan puts the vm_lock back into the vma.  Our reasons for
   pulling it out were largely bogus and that change made the code more
   messy.  This patchset provides small (0-10%) improvements on one
   microbenchmark.
 
 - The 5 patch series "Docs/mm/damon: misc DAMOS filters documentation
   fixes and improves" from SeongJae Park does some maintenance work on the
   DAMON docs.
 
 - The 27 patch series "hugetlb/CMA improvements for large systems" from
   Frank van der Linden addresses a pile of issues which have been observed
   when using CMA on large machines.
 
 - The 2 patch series "mm/damon: introduce DAMOS filter type for unmapped
   pages" from SeongJae Park enables users of DMAON/DAMOS to filter my the
   page's mapped/unmapped status.
 
 - The 19 patch series "zsmalloc/zram: there be preemption" from Sergey
   Senozhatsky teaches zram to run its compression and decompression
   operations preemptibly.
 
 - The 12 patch series "selftests/mm: Some cleanups from trying to run
   them" from Brendan Jackman fixes a pile of unrelated issues which
   Brendan encountered while runnimg our selftests.
 
 - The 2 patch series "fs/proc/task_mmu: add guard region bit to pagemap"
   from Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
   determine whether a particular page is a guard page.
 
 - The 7 patch series "mm, swap: remove swap slot cache" from Kairui Song
   removes the swap slot cache from the allocation path - it simply wasn't
   being effective.
 
 - The 5 patch series "mm: cleanups for device-exclusive entries (hmm)"
   from David Hildenbrand implements a number of unrelated cleanups in this
   code.
 
 - The 5 patch series "mm: Rework generic PTDUMP configs" from Anshuman
   Khandual implements a number of preparatoty cleanups to the
   GENERIC_PTDUMP Kconfig logic.
 
 - The 8 patch series "mm/damon: auto-tune aggregation interval" from
   SeongJae Park implements a feedback-driven automatic tuning feature for
   DAMON's aggregation interval tuning.
 
 - The 5 patch series "Fix lazy mmu mode" from Ryan Roberts fixes some
   issues in powerpc, sparc and x86 lazy MMU implementations.  Ryan did
   this in preparation for implementing lazy mmu mode for arm64 to optimize
   vmalloc.
 
 - The 2 patch series "mm/page_alloc: Some clarifications for migratetype
   fallback" from Brendan Jackman reworks some commentary to make the code
   easier to follow.
 
 - The 3 patch series "page_counter cleanup and size reduction" from
   Shakeel Butt cleans up the page_counter code and fixes a size increase
   which we accidentally added late last year.
 
 - The 3 patch series "Add a command line option that enables control of
   how many threads should be used to allocate huge pages" from Thomas
   Prescher does that.  It allows the careful operator to significantly
   reduce boot time by tuning the parallalization of huge page
   initialization.
 
 - The 3 patch series "Fix calculations in trace_balance_dirty_pages()
   for cgwb" from Tang Yizhou fixes the tracing output from the dirty page
   balancing code.
 
 - The 9 patch series "mm/damon: make allow filters after reject filters
   useful and intuitive" from SeongJae Park improves the handling of allow
   and reject filters.  Behaviour is made more consistent and the
   documention is updated accordingly.
 
 - The 5 patch series "Switch zswap to object read/write APIs" from Yosry
   Ahmed updates zswap to the new object read/write APIs and thus permits
   the removal of some legacy code from zpool and zsmalloc.
 
 - The 6 patch series "Some trivial cleanups for shmem" from Baolin Wang
   does as it claims.
 
 - The 20 patch series "fs/dax: Fix ZONE_DEVICE page reference counts"
   from Alistair Popple regularizes the weird ZONE_DEVICE page refcount
   handling in DAX, permittig the removal of a number of special-case
   checks.
 
 - The 4 patch series "refactor mremap and fix bug" from Lorenzo Stoakes
   is a preparatoty refactoring and cleanup of the mremap() code.
 
 - The 20 patch series "mm: MM owner tracking for large folios (!hugetlb)
   + CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
   which we determine whether a large folio is known to be mapped
   exclusively into a single MM.
 
 - The 8 patch series "mm/damon: add sysfs dirs for managing DAMOS
   filters based on handling layers" from SeongJae Park adds a couple of
   new sysfs directories to ease the management of DAMON/DAMOS filters.
 
 - The 13 patch series "arch, mm: reduce code duplication in mem_init()"
   from Mike Rapoport consolidates many per-arch implementations of
   mem_init() into code generic code, where that is practical.
 
 - The 13 patch series "mm/damon/sysfs: commit parameters online via
   damon_call()" from SeongJae Park continues the cleaning up of sysfs
   access to DAMON internal data.
 
 - The 3 patch series "mm: page_ext: Introduce new iteration API" from
   Luiz Capitulino reworks the page_ext initialization to fix a boot-time
   crash which was observed with an unusual combination of compile and
   cmdline options.
 
 - The 8 patch series "Buddy allocator like (or non-uniform) folio split"
   from Zi Yan reworks the code to split a folio into smaller folios.  The
   main benefit is lessened memory consumption: fewer post-split folios are
   generated.
 
 - The 2 patch series "Minimize xa_node allocation during xarry split"
   from Zi Yan reduces the number of xarray xa_nodes which are generated
   during an xarray split.
 
 - The 2 patch series "drivers/base/memory: Two cleanups" from Gavin Shan
   performs some maintenance work on the drivers/base/memory code.
 
 - The 3 patch series "Add tracepoints for lowmem reserves, watermarks
   and totalreserve_pages" from Martin Liu adds some more tracepoints to
   the page allocator code.
 
 - The 4 patch series "mm/madvise: cleanup requests validations and
   classifications" from SeongJae Park cleans up some warts which SeongJae
   observed during his earlier madvise work.
 
 - The 3 patch series "mm/hwpoison: Fix regressions in memory failure
   handling" from Shuai Xue addresses two quite serious regressions which
   Shuai has observed in the memory-failure implementation.
 
 - The 5 patch series "mm: reliable huge page allocator" from Johannes
   Weiner makes huge page allocations cheaper and more reliable by reducing
   fragmentation.
 
 - The 5 patch series "Minor memcg cleanups & prep for memdescs" from
   Matthew Wilcox is preparatory work for the future implementation of
   memdescs.
 
 - The 4 patch series "track memory used by balloon drivers" from Nico
   Pache introduces a way to track memory used by our various balloon
   drivers.
 
 - The 2 patch series "mm/damon: introduce DAMOS filter type for active
   pages" from Nhat Pham permits users to filter for active/inactive pages,
   separately for file and anon pages.
 
 - The 2 patch series "Adding Proactive Memory Reclaim Statistics" from
   Hao Jia separates the proactive reclaim statistics from the direct
   reclaim statistics.
 
 - The 2 patch series "mm/vmscan: don't try to reclaim hwpoison folio"
   from Jinjiang Tu fixes our handling of hwpoisoned pages within the
   reclaim code.
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Merge tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - The series "Enable strict percpu address space checks" from Uros
   Bizjak uses x86 named address space qualifiers to provide
   compile-time checking of percpu area accesses.

   This has caused a small amount of fallout - two or three issues were
   reported. In all cases the calling code was found to be incorrect.

 - The series "Some cleanup for memcg" from Chen Ridong implements some
   relatively monir cleanups for the memcontrol code.

 - The series "mm: fixes for device-exclusive entries (hmm)" from David
   Hildenbrand fixes a boatload of issues which David found then using
   device-exclusive PTE entries when THP is enabled. More work is
   needed, but this makes thins better - our own HMM selftests now
   succeed.

 - The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed
   remove the z3fold and zbud implementations. They have been deprecated
   for half a year and nobody has complained.

 - The series "mm: further simplify VMA merge operation" from Lorenzo
   Stoakes implements numerous simplifications in this area. No runtime
   effects are anticipated.

 - The series "mm/madvise: remove redundant mmap_lock operations from
   process_madvise()" from SeongJae Park rationalizes the locking in the
   madvise() implementation. Performance gains of 20-25% were observed
   in one MADV_DONTNEED microbenchmark.

 - The series "Tiny cleanup and improvements about SWAP code" from
   Baoquan He contains a number of touchups to issues which Baoquan
   noticed when working on the swap code.

 - The series "mm: kmemleak: Usability improvements" from Catalin
   Marinas implements a couple of improvements to the kmemleak
   user-visible output.

 - The series "mm/damon/paddr: fix large folios access and schemes
   handling" from Usama Arif provides a couple of fixes for DAMON's
   handling of large folios.

 - The series "mm/damon/core: fix wrong and/or useless damos_walk()
   behaviors" from SeongJae Park fixes a few issues with the accuracy of
   kdamond's walking of DAMON regions.

 - The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo
   Stoakes changes the interaction between framebuffer deferred-io and
   core MM. No functional changes are anticipated - this is preparatory
   work for the future removal of page structure fields.

 - The series "mm/damon: add support for hugepage_size DAMOS filter"
   from Usama Arif adds a DAMOS filter which permits the filtering by
   huge page sizes.

 - The series "mm: permit guard regions for file-backed/shmem mappings"
   from Lorenzo Stoakes extends the guard region feature from its
   present "anon mappings only" state. The feature now covers shmem and
   file-backed mappings.

 - The series "mm: batched unmap lazyfree large folios during
   reclamation" from Barry Song cleans up and speeds up the unmapping
   for pte-mapped large folios.

 - The series "reimplement per-vma lock as a refcount" from Suren
   Baghdasaryan puts the vm_lock back into the vma. Our reasons for
   pulling it out were largely bogus and that change made the code more
   messy. This patchset provides small (0-10%) improvements on one
   microbenchmark.

 - The series "Docs/mm/damon: misc DAMOS filters documentation fixes and
   improves" from SeongJae Park does some maintenance work on the DAMON
   docs.

 - The series "hugetlb/CMA improvements for large systems" from Frank
   van der Linden addresses a pile of issues which have been observed
   when using CMA on large machines.

 - The series "mm/damon: introduce DAMOS filter type for unmapped pages"
   from SeongJae Park enables users of DMAON/DAMOS to filter my the
   page's mapped/unmapped status.

 - The series "zsmalloc/zram: there be preemption" from Sergey
   Senozhatsky teaches zram to run its compression and decompression
   operations preemptibly.

 - The series "selftests/mm: Some cleanups from trying to run them" from
   Brendan Jackman fixes a pile of unrelated issues which Brendan
   encountered while runnimg our selftests.

 - The series "fs/proc/task_mmu: add guard region bit to pagemap" from
   Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
   determine whether a particular page is a guard page.

 - The series "mm, swap: remove swap slot cache" from Kairui Song
   removes the swap slot cache from the allocation path - it simply
   wasn't being effective.

 - The series "mm: cleanups for device-exclusive entries (hmm)" from
   David Hildenbrand implements a number of unrelated cleanups in this
   code.

 - The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual
   implements a number of preparatoty cleanups to the GENERIC_PTDUMP
   Kconfig logic.

 - The series "mm/damon: auto-tune aggregation interval" from SeongJae
   Park implements a feedback-driven automatic tuning feature for
   DAMON's aggregation interval tuning.

 - The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in
   powerpc, sparc and x86 lazy MMU implementations. Ryan did this in
   preparation for implementing lazy mmu mode for arm64 to optimize
   vmalloc.

 - The series "mm/page_alloc: Some clarifications for migratetype
   fallback" from Brendan Jackman reworks some commentary to make the
   code easier to follow.

 - The series "page_counter cleanup and size reduction" from Shakeel
   Butt cleans up the page_counter code and fixes a size increase which
   we accidentally added late last year.

 - The series "Add a command line option that enables control of how
   many threads should be used to allocate huge pages" from Thomas
   Prescher does that. It allows the careful operator to significantly
   reduce boot time by tuning the parallalization of huge page
   initialization.

 - The series "Fix calculations in trace_balance_dirty_pages() for cgwb"
   from Tang Yizhou fixes the tracing output from the dirty page
   balancing code.

 - The series "mm/damon: make allow filters after reject filters useful
   and intuitive" from SeongJae Park improves the handling of allow and
   reject filters. Behaviour is made more consistent and the documention
   is updated accordingly.

 - The series "Switch zswap to object read/write APIs" from Yosry Ahmed
   updates zswap to the new object read/write APIs and thus permits the
   removal of some legacy code from zpool and zsmalloc.

 - The series "Some trivial cleanups for shmem" from Baolin Wang does as
   it claims.

 - The series "fs/dax: Fix ZONE_DEVICE page reference counts" from
   Alistair Popple regularizes the weird ZONE_DEVICE page refcount
   handling in DAX, permittig the removal of a number of special-case
   checks.

 - The series "refactor mremap and fix bug" from Lorenzo Stoakes is a
   preparatoty refactoring and cleanup of the mremap() code.

 - The series "mm: MM owner tracking for large folios (!hugetlb) +
   CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
   which we determine whether a large folio is known to be mapped
   exclusively into a single MM.

 - The series "mm/damon: add sysfs dirs for managing DAMOS filters based
   on handling layers" from SeongJae Park adds a couple of new sysfs
   directories to ease the management of DAMON/DAMOS filters.

 - The series "arch, mm: reduce code duplication in mem_init()" from
   Mike Rapoport consolidates many per-arch implementations of
   mem_init() into code generic code, where that is practical.

 - The series "mm/damon/sysfs: commit parameters online via
   damon_call()" from SeongJae Park continues the cleaning up of sysfs
   access to DAMON internal data.

 - The series "mm: page_ext: Introduce new iteration API" from Luiz
   Capitulino reworks the page_ext initialization to fix a boot-time
   crash which was observed with an unusual combination of compile and
   cmdline options.

 - The series "Buddy allocator like (or non-uniform) folio split" from
   Zi Yan reworks the code to split a folio into smaller folios. The
   main benefit is lessened memory consumption: fewer post-split folios
   are generated.

 - The series "Minimize xa_node allocation during xarry split" from Zi
   Yan reduces the number of xarray xa_nodes which are generated during
   an xarray split.

 - The series "drivers/base/memory: Two cleanups" from Gavin Shan
   performs some maintenance work on the drivers/base/memory code.

 - The series "Add tracepoints for lowmem reserves, watermarks and
   totalreserve_pages" from Martin Liu adds some more tracepoints to the
   page allocator code.

 - The series "mm/madvise: cleanup requests validations and
   classifications" from SeongJae Park cleans up some warts which
   SeongJae observed during his earlier madvise work.

 - The series "mm/hwpoison: Fix regressions in memory failure handling"
   from Shuai Xue addresses two quite serious regressions which Shuai
   has observed in the memory-failure implementation.

 - The series "mm: reliable huge page allocator" from Johannes Weiner
   makes huge page allocations cheaper and more reliable by reducing
   fragmentation.

 - The series "Minor memcg cleanups & prep for memdescs" from Matthew
   Wilcox is preparatory work for the future implementation of memdescs.

 - The series "track memory used by balloon drivers" from Nico Pache
   introduces a way to track memory used by our various balloon drivers.

 - The series "mm/damon: introduce DAMOS filter type for active pages"
   from Nhat Pham permits users to filter for active/inactive pages,
   separately for file and anon pages.

 - The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia
   separates the proactive reclaim statistics from the direct reclaim
   statistics.

 - The series "mm/vmscan: don't try to reclaim hwpoison folio" from
   Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim
   code.

* tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits)
  mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex()
  x86/mm: restore early initialization of high_memory for 32-bits
  mm/vmscan: don't try to reclaim hwpoison folio
  mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
  cgroup: docs: add pswpin and pswpout items in cgroup v2 doc
  mm: vmscan: split proactive reclaim statistics from direct reclaim statistics
  selftests/mm: speed up split_huge_page_test
  selftests/mm: uffd-unit-tests support for hugepages > 2M
  docs/mm/damon/design: document active DAMOS filter type
  mm/damon: implement a new DAMOS filter type for active pages
  fs/dax: don't disassociate zero page entries
  MM documentation: add "Unaccepted" meminfo entry
  selftests/mm: add commentary about 9pfs bugs
  fork: use __vmalloc_node() for stack allocation
  docs/mm: Physical Memory: Populate the "Zones" section
  xen: balloon: update the NR_BALLOON_PAGES state
  hv_balloon: update the NR_BALLOON_PAGES state
  balloon_compaction: update the NR_BALLOON_PAGES state
  meminfo: add a per node counter for balloon drivers
  mm: remove references to folio in __memcg_kmem_uncharge_page()
  ...
2025-04-01 09:29:18 -07:00
Linus Torvalds
26d8e43079 vfs-6.15-rc1.async.dir
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Merge tag 'vfs-6.15-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs async dir updates from Christian Brauner:
 "This contains cleanups that fell out of the work from async directory
  handling:

   - Change kern_path_locked() and user_path_locked_at() to never return
     a negative dentry. This simplifies the usability of these helpers
     in various places

   - Drop d_exact_alias() from the remaining place in NFS where it is
     still used. This also allows us to drop the d_exact_alias() helper
     completely

   - Drop an unnecessary call to fh_update() from nfsd_create_locked()

   - Change i_op->mkdir() to return a struct dentry

     Change vfs_mkdir() to return a dentry provided by the filesystems
     which is hashed and positive. This allows us to reduce the number
     of cases where the resulting dentry is not positive to very few
     cases. The code in these places becomes simpler and easier to
     understand.

   - Repack DENTRY_* and LOOKUP_* flags"

* tag 'vfs-6.15-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  doc: fix inline emphasis warning
  VFS: Change vfs_mkdir() to return the dentry.
  nfs: change mkdir inode_operation to return alternate dentry if needed.
  fuse: return correct dentry for ->mkdir
  ceph: return the correct dentry on mkdir
  hostfs: store inode in dentry after mkdir if possible.
  Change inode_operations.mkdir to return struct dentry *
  nfsd: drop fh_update() from S_IFDIR branch of nfsd_create_locked()
  nfs/vfs: discard d_exact_alias()
  VFS: add common error checks to lookup_one_qstr_excl()
  VFS: change kern_path_locked() and user_path_locked_at() to never return negative dentry
  VFS: repack LOOKUP_ bit flags.
  VFS: repack DENTRY_ flags.
2025-03-24 10:47:14 -07:00
Jinjiang Tu
5f5ee52d4f mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
Patch series "mm/vmscan: don't try to reclaim hwpoison folio".

Fix a bug during memory reclaim if folio is hwpoisoned.


This patch (of 2):

Introduce helper folio_contain_hwpoisoned_page() to check if the entire
folio is hwpoisoned or it contains hwpoisoned pages.

Link: https://lkml.kernel.org/r/20250318083939.987651-1-tujinjiang@huawei.com
Link: https://lkml.kernel.org/r/20250318083939.987651-2-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: <stable@vger,kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-21 22:03:16 -07:00
Enrico Bravi
116eb46895 mm/shmem: fix functions documentation
Add missing parenthesis in @name parameter description.

Link: https://lkml.kernel.org/r/20250310112535.84754-1-enrico.bravi@polito.it
Signed-off-by: Enrico Bravi <enrico.bravi@polito.it>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 22:07:02 -07:00
Zi Yan
d53c78fffe mm/shmem: use xas_try_split() in shmem_split_large_entry()
During shmem_split_large_entry(), large swap entries are covering n slots
and an order-0 folio needs to be inserted.

Instead of splitting all n slots, only the 1 slot covered by the folio
need to be split and the remaining n-1 shadow entries can be retained with
orders ranging from 0 to n-1.  This method only requires
(n/XA_CHUNK_SHIFT) new xa_nodes instead of (n % XA_CHUNK_SHIFT) *
(n/XA_CHUNK_SHIFT) new xa_nodes, compared to the original
xas_split_alloc() + xas_split() one.

For example, to split an order-9 large swap entry (assuming XA_CHUNK_SHIFT
is 6), 1 xa_node is needed instead of 8.

xas_try_split_min_order() is used to reduce the number of calls to
xas_try_split() during split.

Link: https://lkml.kernel.org/r/20250314222113.711703-3-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Mattew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Kirill A. Shuemov <kirill.shutemov@linux.intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 22:07:01 -07:00
Baolin Wang
086e66b690 mm: shmem: factor out the within_size logic into a new helper
Factor out the within_size logic into a new helper to remove duplicate
code.

Link: https://lkml.kernel.org/r/527dea9d7e32fe6b94c7fe00df2c126203017911.1738918357.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 00:05:42 -07:00
Baolin Wang
cd81c424b5 mm: shmem: change the return value of shmem_find_swap_entries()
The shmem_find_swap_entries() originally returned the index corresponding
to the swap entry, but no callers used this return value.  It should
return the number of entries that were found like other functions, which
can be used by the callers.

No functional changes.

Link: https://lkml.kernel.org/r/070489b5946b8379b2a2d25f78115cef167cd145.1738918357.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 00:05:42 -07:00
Baolin Wang
d5e4e147c0 mm: shmem: remove duplicate error validation
Remove duplicate error code checks for 'start' and 'end', as the
get_order_from_str() will only return -EINVAL if the cmdline string is
configured incorrectly.

Link: https://lkml.kernel.org/r/dfadaba4c8b24c5ae1467fe8b6744b654c65ec91.1738918357.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 00:05:42 -07:00
Baolin Wang
6d26a149f5 mm: shmem: remove 'fadvise()' comments
Similar to commit 255ff62d1586 ("docs: tmpfs: drop 'fadvise()' from the
documentation"), fadvise() has no HUGEPAGE advise currently.  Remove the
confusing fadvise() comments.

Link: https://lkml.kernel.org/r/fae702b9775f58b55b45be5eaad22d8586d0290a.1738918357.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 00:05:41 -07:00
Baolin Wang
c0d017896b mm: shmem: drop the unused macro
Patch series "Some trivial cleanups for shmem".

Patch 1 - Patch 5 do some trivial cleanups and refactoring for shmem.
Patch 6 adds myself as shmem reviewer.


This patch (of 6):

Drop the unused 'BLOCKS_PER_PAGE' macro.

Link: https://lkml.kernel.org/r/cover.1738918357.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/69264cee1d938442477e657004e4924f8a5c4dd4.1738918357.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 00:05:41 -07:00
Kairui Song
b487a2da35 mm, swap: simplify folio swap allocation
With slot cache gone, clean up the allocation helpers even more. 
folio_alloc_swap will be the only entry for allocation and adding the
folio to swap cache (except suspend), making it opposite of
folio_free_swap.

Link: https://lkml.kernel.org/r/20250313165935.63303-8-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16 22:06:44 -07:00
Johannes Weiner
89ce924f0b mm: memcontrol: move memsw charge callbacks to v1
The interweaving of two entirely different swap accounting strategies has
been one of the more confusing parts of the memcg code.  Split out the v1
code to clarify the implementation and a handful of callsites, and to
avoid building the v1 bits when !CONFIG_MEMCG_V1.

   text	  data	   bss	   dec	   hex	filename
  39253	  6446	  4160	 49859	  c2c3	mm/memcontrol.o.old
  38877	  6382	  4160	 49419	  c10b	mm/memcontrol.o

Link: https://lkml.kernel.org/r/20250124054132.45643-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Balbir Singh <balbirs@nvidia.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16 22:05:55 -07:00
Linus Torvalds
1110ce6a1e 33 hotfixes. 24 are cc:stable and the remainder address post-6.13 issues
or aren't considered necessary for -stable kernels.
 
 26 are for MM and 7 are for non-MM.
 
 - "mm: memory_failure: unmap poisoned folio during migrate properly"
   from Ma Wupeng fixes a couple of two year old bugs involving the
   migration of hwpoisoned folios.
 
 - "selftests/damon: three fixes for false results" from SeongJae Park
   fixes three one year old bugs in the SAMON selftest code.
 
 The remainder are singletons and doubletons.  Please see the individual
 changelogs for details.
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Merge tag 'mm-hotfixes-stable-2025-03-08-16-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "33 hotfixes. 24 are cc:stable and the remainder address post-6.13
  issues or aren't considered necessary for -stable kernels.

  26 are for MM and 7 are for non-MM.

   - "mm: memory_failure: unmap poisoned folio during migrate properly"
     from Ma Wupeng fixes a couple of two year old bugs involving the
     migration of hwpoisoned folios.

   - "selftests/damon: three fixes for false results" from SeongJae Park
     fixes three one year old bugs in the SAMON selftest code.

  The remainder are singletons and doubletons. Please see the individual
  changelogs for details"

* tag 'mm-hotfixes-stable-2025-03-08-16-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (33 commits)
  mm/page_alloc: fix uninitialized variable
  rapidio: add check for rio_add_net() in rio_scan_alloc_net()
  rapidio: fix an API misues when rio_add_net() fails
  MAINTAINERS: .mailmap: update Sumit Garg's email address
  Revert "mm/page_alloc.c: don't show protection in zone's ->lowmem_reserve[] for empty zone"
  mm: fix finish_fault() handling for large folios
  mm: don't skip arch_sync_kernel_mappings() in error paths
  mm: shmem: remove unnecessary warning in shmem_writepage()
  userfaultfd: fix PTE unmapping stack-allocated PTE copies
  userfaultfd: do not block on locking a large folio with raised refcount
  mm: zswap: use ATOMIC_LONG_INIT to initialize zswap_stored_pages
  mm: shmem: fix potential data corruption during shmem swapin
  mm: fix kernel BUG when userfaultfd_move encounters swapcache
  selftests/damon/damon_nr_regions: sort collected regiosn before checking with min/max boundaries
  selftests/damon/damon_nr_regions: set ops update for merge results check to 100ms
  selftests/damon/damos_quota: make real expectation of quota exceeds
  include/linux/log2.h: mark is_power_of_2() with __always_inline
  NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback
  mm, swap: avoid BUG_ON in relocate_cluster()
  mm: swap: use correct step in loop to wait all clusters in wait_for_allocation()
  ...
2025-03-08 14:34:06 -10:00
Linus Torvalds
00a7d39898 fs/pipe: add simpler helpers for common cases
The fix to atomically read the pipe head and tail state when not holding
the pipe mutex has caused a number of headaches due to the size change
of the involved types.

It turns out that we don't have _that_ many places that access these
fields directly and were affected, but we have more than we strictly
should have, because our low-level helper functions have been designed
to have intimate knowledge of how the pipes work.

And as a result, that random noise of direct 'pipe->head' and
'pipe->tail' accesses makes it harder to pinpoint any actual potential
problem spots remaining.

For example, we didn't have a "is the pipe full" helper function, but
instead had a "given these pipe buffer indexes and this pipe size, is
the pipe full".  That's because some low-level pipe code does actually
want that much more complicated interface.

But most other places literally just want a "is the pipe full" helper,
and not having it meant that those places ended up being unnecessarily
much too aware of this all.

It would have been much better if only the very core pipe code that
cared had been the one aware of this all.

So let's fix it - better late than never.  This just introduces the
trivial wrappers for "is this pipe full or empty" and to get how many
pipe buffers are used, so that instead of writing

        if (pipe_full(pipe->head, pipe->tail, pipe->max_usage))

the places that literally just want to know if a pipe is full can just
say

        if (pipe_is_full(pipe))

instead.  The existing trivial cases were converted with a 'sed' script.

This cuts down on the places that access pipe->head and pipe->tail
directly outside of the pipe code (and core splice code) quite a lot.

The splice code in particular still revels in doing the direct low-level
accesses, and the fuse fuse_dev_splice_write() code also seems a bit
unnecessarily eager to go very low-level, but it's at least a bit better
than it used to be.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2025-03-06 18:25:35 -10:00
Ricardo Cañuelo Navarro
adae46ac1e mm: shmem: remove unnecessary warning in shmem_writepage()
Although the scenario where shmem_writepage() is called with info->flags &
VM_LOCKED is unlikely to happen, it's still possible, as evidenced by
syzbot [1].  However, the warning in this case isn't necessary because the
situation is already handled correctly [2].

[2] https://lore.kernel.org/lkml/8afe1f7f-31a2-4fc0-1fbd-f9ba8a116fe3@google.com/

Link: https://lkml.kernel.org/r/20250226-20250221-warning-in-shmem_writepage-v1-1-5ad19420e17e@igalia.com
Fixes: 9a976f0c847b ("shmem: skip page split if we're not reclaiming")
Signed-off-by: Ricardo Cañuelo Navarro <rcn@igalia.com>
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Closes: https://lore.kernel.org/lkml/ZZ9PShXjKJkVelNm@xpf.sh.intel.com/ [1]
Suggested-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Florent Revest <revest@chromium.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-05 21:36:18 -08:00
Baolin Wang
058313515d mm: shmem: fix potential data corruption during shmem swapin
Alex and Kairui reported some issues (system hang or data corruption) when
swapping out or swapping in large shmem folios.  This is especially easy
to reproduce when the tmpfs is mount with the 'huge=within_size'
parameter.  Thanks to Kairui's reproducer, the issue can be easily
replicated.

The root cause of the problem is that swap readahead may asynchronously
swap in order 0 folios into the swap cache, while the shmem mapping can
still store large swap entries.  Then an order 0 folio is inserted into
the shmem mapping without splitting the large swap entry, which overwrites
the original large swap entry, leading to data corruption.

When getting a folio from the swap cache, we should split the large swap
entry stored in the shmem mapping if the orders do not match, to fix this
issue.

Link: https://lkml.kernel.org/r/2fe47c557e74e9df5fe2437ccdc6c9115fa1bf70.1740476943.git.baolin.wang@linux.alibaba.com
Fixes: 809bc86517cc ("mm: shmem: support large folio swap out")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reported-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Reported-by: Kairui Song <ryncsn@gmail.com>
Closes: https://lore.kernel.org/all/1738717785.im3r5g2vxc.none@localhost/
Tested-by: Kairui Song <kasong@tencent.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcow <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-05 21:36:17 -08:00
NeilBrown
88d5baf690
Change inode_operations.mkdir to return struct dentry *
Some filesystems, such as NFS, cifs, ceph, and fuse, do not have
complete control of sequencing on the actual filesystem (e.g.  on a
different server) and may find that the inode created for a mkdir
request already exists in the icache and dcache by the time the mkdir
request returns.  For example, if the filesystem is mounted twice the
directory could be visible on the other mount before it is on the
original mount, and a pair of name_to_handle_at(), open_by_handle_at()
calls could instantiate the directory inode with an IS_ROOT() dentry
before the first mkdir returns.

This means that the dentry passed to ->mkdir() may not be the one that
is associated with the inode after the ->mkdir() completes.  Some
callers need to interact with the inode after the ->mkdir completes and
they currently need to perform a lookup in the (rare) case that the
dentry is no longer hashed.

This lookup-after-mkdir requires that the directory remains locked to
avoid races.  Planned future patches to lock the dentry rather than the
directory will mean that this lookup cannot be performed atomically with
the mkdir.

To remove this barrier, this patch changes ->mkdir to return the
resulting dentry if it is different from the one passed in.
Possible returns are:
  NULL - the directory was created and no other dentry was used
  ERR_PTR() - an error occurred
  non-NULL - this other dentry was spliced in

This patch only changes file-systems to return "ERR_PTR(err)" instead of
"err" or equivalent transformations.  Subsequent patches will make
further changes to some file-systems to return a correct dentry.

Not all filesystems reliably result in a positive hashed dentry:

- NFS, cifs, hostfs will sometimes need to perform a lookup of
  the name to get inode information.  Races could result in this
  returning something different. Note that this lookup is
  non-atomic which is what we are trying to avoid.  Placing the
  lookup in filesystem code means it only happens when the filesystem
  has no other option.
- kernfs and tracefs leave the dentry negative and the ->revalidate
  operation ensures that lookup will be called to correctly populate
  the dentry.  This could be fixed but I don't think it is important
  to any of the users of vfs_mkdir() which look at the dentry.

The recommendation to use
    d_drop();d_splice_alias()
is ugly but fits with current practice.  A planned future patch will
change this.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27 20:00:17 +01:00
Linus Torvalds
9c5968db9e The various patchsets are summarized below. Plus of course many
indivudual patches which are described in their changelogs.
 
 - "Allocate and free frozen pages" from Matthew Wilcox reorganizes the
   page allocator so we end up with the ability to allocate and free
   zero-refcount pages.  So that callers (ie, slab) can avoid a refcount
   inc & dec.
 
 - "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to use
   large folios other than PMD-sized ones.
 
 - "Fix mm/rodata_test" from Petr Tesarik performs some maintenance and
   fixes for this small built-in kernel selftest.
 
 - "mas_anode_descend() related cleanup" from Wei Yang tidies up part of
   the mapletree code.
 
 - "mm: fix format issues and param types" from Keren Sun implements a
   few minor code cleanups.
 
 - "simplify split calculation" from Wei Yang provides a few fixes and a
   test for the mapletree code.
 
 - "mm/vma: make more mmap logic userland testable" from Lorenzo Stoakes
   continues the work of moving vma-related code into the (relatively) new
   mm/vma.c.
 
 - "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David
   Hildenbrand cleans up and rationalizes handling of gfp flags in the page
   allocator.
 
 - "readahead: Reintroduce fix for improper RA window sizing" from Jan
   Kara is a second attempt at fixing a readahead window sizing issue.  It
   should reduce the amount of unnecessary reading.
 
 - "synchronously scan and reclaim empty user PTE pages" from Qi Zheng
   addresses an issue where "huge" amounts of pte pagetables are
   accumulated
   (https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/).
   Qi's series addresses this windup by synchronously freeing PTE memory
   within the context of madvise(MADV_DONTNEED).
 
 - "selftest/mm: Remove warnings found by adding compiler flags" from
   Muhammad Usama Anjum fixes some build warnings in the selftests code
   when optional compiler warnings are enabled.
 
 - "mm: don't use __GFP_HARDWALL when migrating remote pages" from David
   Hildenbrand tightens the allocator's observance of __GFP_HARDWALL.
 
 - "pkeys kselftests improvements" from Kevin Brodsky implements various
   fixes and cleanups in the MM selftests code, mainly pertaining to the
   pkeys tests.
 
 - "mm/damon: add sample modules" from SeongJae Park enhances DAMON to
   estimate application working set size.
 
 - "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn
   provides some cleanups to memcg's hugetlb charging logic.
 
 - "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song
   removes the global swap cgroup lock.  A speedup of 10% for a tmpfs-based
   kernel build was demonstrated.
 
 - "zram: split page type read/write handling" from Sergey Senozhatsky
   has several fixes and cleaups for zram in the area of zram_write_page().
   A watchdog softlockup warning was eliminated.
 
 - "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin Brodsky
   cleans up the pagetable destructor implementations.  A rare
   use-after-free race is fixed.
 
 - "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes
   simplifies and cleans up the debugging code in the VMA merging logic.
 
 - "Account page tables at all levels" from Kevin Brodsky cleans up and
   regularizes the pagetable ctor/dtor handling.  This results in
   improvements in accounting accuracy.
 
 - "mm/damon: replace most damon_callback usages in sysfs with new core
   functions" from SeongJae Park cleans up and generalizes DAMON's sysfs
   file interface logic.
 
 - "mm/damon: enable page level properties based monitoring" from
   SeongJae Park increases the amount of information which is presented in
   response to DAMOS actions.
 
 - "mm/damon: remove DAMON debugfs interface" from SeongJae Park removes
   DAMON's long-deprecated debugfs interfaces.  Thus the migration to sysfs
   is completed.
 
 - "mm/hugetlb: Refactor hugetlb allocation resv accounting" from Peter
   Xu cleans up and generalizes the hugetlb reservation accounting.
 
 - "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino
   removes a never-used feature of the alloc_pages_bulk() interface.
 
 - "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park
   extends DAMOS filters to support not only exclusion (rejecting), but
   also inclusion (allowing) behavior.
 
 - "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi
   "introduces a new memory descriptor for zswap.zpool that currently
   overlaps with struct page for now.  This is part of the effort to reduce
   the size of struct page and to enable dynamic allocation of memory
   descriptors."
 
 - "mm, swap: rework of swap allocator locks" from Kairui Song redoes and
   simplifies the swap allocator locking.  A speedup of 400% was
   demonstrated for one workload.  As was a 35% reduction for kernel build
   time with swap-on-zram.
 
 - "mm: update mips to use do_mmap(), make mmap_region() internal" from
   Lorenzo Stoakes reworks MIPS's use of mmap_region() so that
   mmap_region() can be made MM-internal.
 
 - "mm/mglru: performance optimizations" from Yu Zhao fixes a few MGLRU
   regressions and otherwise improves MGLRU performance.
 
 - "Docs/mm/damon: add tuning guide and misc updates" from SeongJae Park
   updates DAMON documentation.
 
 - "Cleanup for memfd_create()" from Isaac Manjarres does that thing.
 
 - "mm: hugetlb+THP folio and migration cleanups" from David Hildenbrand
   provides various cleanups in the areas of hugetlb folios, THP folios and
   migration.
 
 - "Uncached buffered IO" from Jens Axboe implements the new
   RWF_DONTCACHE flag which provides synchronous dropbehind for pagecache
   reading and writing.  To permite userspace to address issues with
   massive buildup of useless pagecache when reading/writing fast devices.
 
 - "selftests/mm: virtual_address_range: Reduce memory" from Thomas
   Weißschuh fixes and optimizes some of the MM selftests.
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Merge tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "The various patchsets are summarized below. Plus of course many
  indivudual patches which are described in their changelogs.

   - "Allocate and free frozen pages" from Matthew Wilcox reorganizes
     the page allocator so we end up with the ability to allocate and
     free zero-refcount pages. So that callers (ie, slab) can avoid a
     refcount inc & dec

   - "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to
     use large folios other than PMD-sized ones

   - "Fix mm/rodata_test" from Petr Tesarik performs some maintenance
     and fixes for this small built-in kernel selftest

   - "mas_anode_descend() related cleanup" from Wei Yang tidies up part
     of the mapletree code

   - "mm: fix format issues and param types" from Keren Sun implements a
     few minor code cleanups

   - "simplify split calculation" from Wei Yang provides a few fixes and
     a test for the mapletree code

   - "mm/vma: make more mmap logic userland testable" from Lorenzo
     Stoakes continues the work of moving vma-related code into the
     (relatively) new mm/vma.c

   - "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David
     Hildenbrand cleans up and rationalizes handling of gfp flags in the
     page allocator

   - "readahead: Reintroduce fix for improper RA window sizing" from Jan
     Kara is a second attempt at fixing a readahead window sizing issue.
     It should reduce the amount of unnecessary reading

   - "synchronously scan and reclaim empty user PTE pages" from Qi Zheng
     addresses an issue where "huge" amounts of pte pagetables are
     accumulated:

       https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/

     Qi's series addresses this windup by synchronously freeing PTE
     memory within the context of madvise(MADV_DONTNEED)

   - "selftest/mm: Remove warnings found by adding compiler flags" from
     Muhammad Usama Anjum fixes some build warnings in the selftests
     code when optional compiler warnings are enabled

   - "mm: don't use __GFP_HARDWALL when migrating remote pages" from
     David Hildenbrand tightens the allocator's observance of
     __GFP_HARDWALL

   - "pkeys kselftests improvements" from Kevin Brodsky implements
     various fixes and cleanups in the MM selftests code, mainly
     pertaining to the pkeys tests

   - "mm/damon: add sample modules" from SeongJae Park enhances DAMON to
     estimate application working set size

   - "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn
     provides some cleanups to memcg's hugetlb charging logic

   - "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song
     removes the global swap cgroup lock. A speedup of 10% for a
     tmpfs-based kernel build was demonstrated

   - "zram: split page type read/write handling" from Sergey Senozhatsky
     has several fixes and cleaups for zram in the area of
     zram_write_page(). A watchdog softlockup warning was eliminated

   - "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin
     Brodsky cleans up the pagetable destructor implementations. A rare
     use-after-free race is fixed

   - "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes
     simplifies and cleans up the debugging code in the VMA merging
     logic

   - "Account page tables at all levels" from Kevin Brodsky cleans up
     and regularizes the pagetable ctor/dtor handling. This results in
     improvements in accounting accuracy

   - "mm/damon: replace most damon_callback usages in sysfs with new
     core functions" from SeongJae Park cleans up and generalizes
     DAMON's sysfs file interface logic

   - "mm/damon: enable page level properties based monitoring" from
     SeongJae Park increases the amount of information which is
     presented in response to DAMOS actions

   - "mm/damon: remove DAMON debugfs interface" from SeongJae Park
     removes DAMON's long-deprecated debugfs interfaces. Thus the
     migration to sysfs is completed

   - "mm/hugetlb: Refactor hugetlb allocation resv accounting" from
     Peter Xu cleans up and generalizes the hugetlb reservation
     accounting

   - "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino
     removes a never-used feature of the alloc_pages_bulk() interface

   - "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park
     extends DAMOS filters to support not only exclusion (rejecting),
     but also inclusion (allowing) behavior

   - "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi
     introduces a new memory descriptor for zswap.zpool that currently
     overlaps with struct page for now. This is part of the effort to
     reduce the size of struct page and to enable dynamic allocation of
     memory descriptors

   - "mm, swap: rework of swap allocator locks" from Kairui Song redoes
     and simplifies the swap allocator locking. A speedup of 400% was
     demonstrated for one workload. As was a 35% reduction for kernel
     build time with swap-on-zram

   - "mm: update mips to use do_mmap(), make mmap_region() internal"
     from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that
     mmap_region() can be made MM-internal

   - "mm/mglru: performance optimizations" from Yu Zhao fixes a few
     MGLRU regressions and otherwise improves MGLRU performance

   - "Docs/mm/damon: add tuning guide and misc updates" from SeongJae
     Park updates DAMON documentation

   - "Cleanup for memfd_create()" from Isaac Manjarres does that thing

   - "mm: hugetlb+THP folio and migration cleanups" from David
     Hildenbrand provides various cleanups in the areas of hugetlb
     folios, THP folios and migration

   - "Uncached buffered IO" from Jens Axboe implements the new
     RWF_DONTCACHE flag which provides synchronous dropbehind for
     pagecache reading and writing. To permite userspace to address
     issues with massive buildup of useless pagecache when
     reading/writing fast devices

   - "selftests/mm: virtual_address_range: Reduce memory" from Thomas
     Weißschuh fixes and optimizes some of the MM selftests"

* tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
  mm/compaction: fix UBSAN shift-out-of-bounds warning
  s390/mm: add missing ctor/dtor on page table upgrade
  kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags()
  tools: add VM_WARN_ON_VMG definition
  mm/damon/core: use str_high_low() helper in damos_wmark_wait_us()
  seqlock: add missing parameter documentation for raw_seqcount_try_begin()
  mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh
  mm/page_alloc: remove the incorrect and misleading comment
  zram: remove zcomp_stream_put() from write_incompressible_page()
  mm: separate move/undo parts from migrate_pages_batch()
  mm/kfence: use str_write_read() helper in get_access_type()
  selftests/mm/mkdirty: fix memory leak in test_uffdio_copy()
  kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags()
  selftests/mm: virtual_address_range: avoid reading from VM_IO mappings
  selftests/mm: vm_util: split up /proc/self/smaps parsing
  selftests/mm: virtual_address_range: unmap chunks after validation
  selftests/mm: virtual_address_range: mmap() without PROT_WRITE
  selftests/memfd/memfd_test: fix possible NULL pointer dereference
  mm: add FGP_DONTCACHE folio creation flag
  mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue
  ...
2025-01-26 18:36:23 -08:00
Baolin Wang
1dd44c0af4 mm: shmem: skip swapcache for swapin of synchronous swap device
With fast swap devices (such as zram), swapin latency is crucial to
applications.  For shmem swapin, similar to anonymous memory swapin, we
can skip the swapcache operation to improve swapin latency.  Testing 1G
shmem sequential swapin without THP enabled, I observed approximately a 6%
performance improvement: (Note: I repeated 5 times and took the mean data
for each test)

w/o patch	w/ patch	changes
534.8ms		501ms		+6.3%

In addition, currently, we always split the large swap entry stored in the
shmem mapping during shmem large folio swapin, which is not perfect,
especially with a fast swap device.  We should swap in the whole large
folio instead of splitting the precious large folios to take advantage of
the large folios and improve the swapin latency if the swap device is
synchronous device, which is similar to anonymous memory mTHP swapin. 
Testing 1G shmem sequential swapin with 64K mTHP and 2M mTHP, I observed
obvious performance improvement:

mTHP=64K
w/o patch	w/ patch	changes
550.4ms		169.6ms		+69%

mTHP=2M
w/o patch	w/ patch	changes
542.8ms		126.8ms		+77%

Note that skipping swapcache requires attention to concurrent swapin
scenarios.  Fortunately the swapcache_prepare() and
shmem_add_to_page_cache() can help identify concurrent swapin and large
swap entry split scenarios, and return -EEXIST for retry.

[akpm@linux-foundation.org: use IS_ENABLED(), tweak comment grammar]
Link: https://lkml.kernel.org/r/3d9f3bd3bc6ec953054baff5134f66feeaae7c1e.1736301701.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-25 20:22:30 -08:00
Linus Torvalds
7e587c20ad vfs-6.14-rc1.libfs
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Merge tag 'vfs-6.14-rc1.libfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs libfs updates from Christian Brauner:
 "This improves the stable directory offset behavior in various ways.

  Stable offsets are needed so that NFS can reliably read directories on
  filesystems such as tmpfs:

   - Improve the end-of-directory detection

     According to getdents(3), the d_off field in each returned
     directory entry points to the next entry in the directory. The
     d_off field in the last returned entry in the readdir buffer must
     contain a valid offset value, but if it points to an actual
     directory entry, then readdir/getdents can loop.

     Introduce a specific fixed offset value that is placed in the d_off
     field of the last entry in a directory. Some user space
     applications assume that the EOD offset value is larger than the
     offsets of real directory entries, so the largest valid offset
     value is reserved for this purpose. This new value is never
     allocated by simple_offset_add().

     When ->iterate_dir() returns, getdents{64} inserts the ctx->pos
     value into the d_off field of the last valid entry in the readdir
     buffer. When it hits EOD, offset_readdir() sets ctx->pos to the EOD
     offset value so the last entry is updated to point to the EOD
     marker.

     When trying to read the entry at the EOD offset, offset_readdir()
     terminates immediately.

   - Rely on d_children to iterate stable offset directories

     Instead of using the mtree to emit entries in the order of their
     offset values, use it only to map incoming ctx->pos to a starting
     entry. Then use the directory's d_children list, which is already
     maintained properly by the dcache, to find the next child to emit.

   - Narrow the range of directory offset values returned by
     simple_offset_add() to 3 .. (S32_MAX - 1) on all platforms. This
     means the allocation behavior is identical on 32-bit systems,
     64-bit systems, and 32-bit user space on 64-bit kernels. The new
     range still permits over 2 billion concurrent entries per
     directory.

   - Return ENOSPC when the directory offset range is exhausted. Hitting
     this error is almost impossible though.

   - Remove the simple_offset_empty() helper"

* tag 'vfs-6.14-rc1.libfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  libfs: Use d_children list to iterate simple_offset directories
  libfs: Replace simple_offset end-of-directory detection
  Revert "libfs: fix infinite directory reads for offset dir"
  Revert "libfs: Add simple_offset_empty()"
  libfs: Return ENOSPC when the directory offset range is exhausted
2025-01-20 11:00:53 -08:00
Linus Torvalds
4b84a4c8d4 vfs-6.14-rc1.misc
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Merge tag 'vfs-6.14-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "Features:

   - Support caching symlink lengths in inodes

     The size is stored in a new union utilizing the same space as
     i_devices, thus avoiding growing the struct or taking up any more
     space

     When utilized it dodges strlen() in vfs_readlink(), giving about
     1.5% speed up when issuing readlink on /initrd.img on ext4

   - Add RWF_DONTCACHE iocb and FOP_DONTCACHE file_operations flag

     If a file system supports uncached buffered IO, it may set
     FOP_DONTCACHE and enable support for RWF_DONTCACHE.

     If RWF_DONTCACHE is attempted without the file system supporting
     it, it'll get errored with -EOPNOTSUPP

   - Enable VBOXGUEST and VBOXSF_FS on ARM64

     Now that VirtualBox is able to run as a host on arm64 (e.g. the
     Apple M3 processors) we can enable VBOXSF_FS (and in turn
     VBOXGUEST) for this architecture.

     Tested with various runs of bonnie++ and dbench on an Apple MacBook
     Pro with the latest Virtualbox 7.1.4 r165100 installed

  Cleanups:

   - Delay sysctl_nr_open check in expand_files()

   - Use kernel-doc includes in fiemap docbook

   - Use page->private instead of page->index in watch_queue

   - Use a consume fence in mnt_idmap() as it's heavily used in
     link_path_walk()

   - Replace magic number 7 with ARRAY_SIZE() in fc_log

   - Sort out a stale comment about races between fd alloc and dup2()

   - Fix return type of do_mount() from long to int

   - Various cosmetic cleanups for the lockref code

  Fixes:

   - Annotate spinning as unlikely() in __read_seqcount_begin

     The annotation already used to be there, but got lost in commit
     52ac39e5db51 ("seqlock: seqcount_t: Implement all read APIs as
     statement expressions")

   - Fix proc_handler for sysctl_nr_open

   - Flush delayed work in delayed fput()

   - Fix grammar and spelling in propagate_umount()

   - Fix ESP not readable during coredump

     In /proc/PID/stat, there is the kstkesp field which is the stack
     pointer of a thread. While the thread is active, this field reads
     zero. But during a coredump, it should have a valid value

     However, at the moment, kstkesp is zero even during coredump

   - Don't wake up the writer if the pipe is still full

   - Fix unbalanced user_access_end() in select code"

* tag 'vfs-6.14-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (28 commits)
  gfs2: use lockref_init for qd_lockref
  erofs: use lockref_init for pcl->lockref
  dcache: use lockref_init for d_lockref
  lockref: add a lockref_init helper
  lockref: drop superfluous externs
  lockref: use bool for false/true returns
  lockref: improve the lockref_get_not_zero description
  lockref: remove lockref_put_not_zero
  fs: Fix return type of do_mount() from long to int
  select: Fix unbalanced user_access_end()
  vbox: Enable VBOXGUEST and VBOXSF_FS on ARM64
  pipe_read: don't wake up the writer if the pipe is still full
  selftests: coredump: Add stackdump test
  fs/proc: do_task_stat: Fix ESP not readable during coredump
  fs: add RWF_DONTCACHE iocb and FOP_DONTCACHE file_operations flag
  fs: sort out a stale comment about races between fd alloc and dup2
  fs: Fix grammar and spelling in propagate_umount()
  fs: fc_log replace magic number 7 with ARRAY_SIZE()
  fs: use a consume fence in mnt_idmap()
  file: flush delayed work in delayed fput()
  ...
2025-01-20 09:40:49 -08:00
Karan Sanghavi
b071cc3546 mm: shmem: use signed int for version handling in casefold option
Fixes an issue where the use of an unsigned data type in
`shmem_parse_opt_casefold()` caused incorrect evaluation of negative
conditions.

Link: https://lkml.kernel.org/r/20250111-unsignedcompare1601569-v3-1-c861b4221831@gmail.com
Fixes: 58e55efd6c72 ("tmpfs: Add casefold lookup support")
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Karan Sanghavi <karansanghvi98@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Hugh Dickens <hughd@google.com>
Cc: Shuah khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-15 21:15:43 -08:00
Lorenzo Stoakes
fa00b8ef18 mm: perform all memfd seal checks in a single place
We no longer actually need to perform these checks in the f_op->mmap()
hook any longer.

We already moved the operation which clears VM_MAYWRITE on a read-only
mapping of a write-sealed memfd in order to work around the restrictions
imposed by commit 5de195060b2e ("mm: resolve faulty mmap_region() error
path behaviour").

There is no reason for us not to simply go ahead and additionally check to
see if any pre-existing seals are in place here rather than defer this to
the f_op->mmap() hook.

By doing this we remove more logic from shmem_mmap() which doesn't belong
there, as well as doing the same for hugetlbfs_file_mmap().  We also
remove dubious shared logic in mm.h which simply does not belong there
either.

It makes sense to do these checks at the earliest opportunity, we know
these are shmem (or hugetlbfs) mappings whose relevant VMA flags will not
change from the invoking do_mmap() so there is simply no need to wait.

This also means the implementation of further memfd seal flags can be done
within mm/memfd.c and also have the opportunity to modify VMA flags as
necessary early in the mapping logic.

[lorenzo.stoakes@oracle.com: fix typos in !memfd inline stub]
  Link: https://lkml.kernel.org/r/7dee6c5d-480b-4c24-b98e-6fa47dbd8a23@lucifer.local
Link: https://lkml.kernel.org/r/20241206212846.210835-1-lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jeff Xu <jeffxu@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-13 22:40:51 -08:00
Guo Weikang
a474d84359 mm/shmem: refactor to reuse vfs_parse_monolithic_sep for option parsing
shmem_parse_options() is refactored to use vfs_parse_monolithic_sep() with
a custom separator function, shmem_next_opt().  This eliminates redundant
logic for parsing comma-separated options and ensures consistency with
other kernel code that uses the same interface.

The vfs_parse_monolithic_sep() helper was introduced in commit
e001d1447cd4 ("fs: factor out vfs_parse_monolithic_sep() helper").

Link: https://lkml.kernel.org/r/20241205094521.1244678-1-guoweikang.kernel@gmail.com
Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-13 22:40:49 -08:00
Baolin Wang
d635ccdb43 mm: shmem: add a kernel command line to change the default huge policy for tmpfs
Now the tmpfs can allow to allocate any sized large folios, and the default
huge policy is still preferred to be 'never'. Due to tmpfs not behaving like
other file systems in some cases as previously explained by David[1]:

: I think I raised this in the past, but tmpfs/shmem is just like any
: other file system .. except it sometimes really isn't and behaves much
: more like (swappable) anonymous memory. (or mlocked files)
: 
: There are many systems out there that run without swap enabled, or with
: extremely minimal swap (IIRC until recently kubernetes was completely
: incompatible with swapping). Swap can even be disabled today for shmem
: using a mount option.
: 
: That's a big difference to all other file systems where you are
: guaranteed to have backend storage where you can simply evict under
: memory pressure (might temporarily fail, of course).
: 
: I *think* that's the reason why we have the "huge=" parameter that also
: controls the THP allocations during page faults (IOW possible memory
: over-allocation). Maybe also because it was a new feature, and we only
: had a single THP size.

Thus adding a new command line to change the default huge policy will be
helpful to use the large folios for tmpfs, which is similar to the
'transparent_hugepage_shmem' cmdline for shmem.

[1] https://lore.kernel.org/all/cbadd5fe-69d5-4c21-8eb8-3344ed36c721@redhat.com/

Link: https://lkml.kernel.org/r/ff390b2656f0d39649547f8f2cbb30fcb7e7be2d.1732779148.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-13 22:40:37 -08:00
Baolin Wang
acd7ccb284 mm: shmem: add large folio support for tmpfs
Add large folio support for tmpfs write and fallocate paths matching the
same high order preference mechanism used in the iomap buffered IO path as
used in __filemap_get_folio().

Add shmem_mapping_size_orders() to get a hint for the orders of the folio
based on the file size which takes care of the mapping requirements.

Traditionally, tmpfs only supported PMD-sized large folios.  However
nowadays with other file systems supporting any sized large folios, and
extending anonymous to support mTHP, we should not restrict tmpfs to
allocating only PMD-sized large folios, making it more special.  Instead,
we should allow tmpfs can allocate any sized large folios.

Considering that tmpfs already has the 'huge=' option to control the
PMD-sized large folios allocation, we can extend the 'huge=' option to
allow any sized large folios.  The semantics of the 'huge=' mount option
are:

huge=never: no any sized large folios
huge=always: any sized large folios
huge=within_size: like 'always' but respect the i_size
huge=advise: like 'always' if requested with madvise()

Note: for tmpfs mmap() faults, due to the lack of a write size hint, still
allocate the PMD-sized huge folios if huge=always/within_size/advise is
set.

Moreover, the 'deny' and 'force' testing options controlled by
'/sys/kernel/mm/transparent_hugepage/shmem_enabled', still retain the same
semantics.  The 'deny' can disable any sized large folios for tmpfs, while
the 'force' can enable PMD sized large folios for tmpfs.

Link: https://lkml.kernel.org/r/035bf55fbdebeff65f5cb2cdb9907b7d632c3228.1732779148.git.baolin.wang@linux.alibaba.com
Co-developed-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-13 22:40:36 -08:00
Baolin Wang
736bbc6825 mm: shmem: change shmem_huge_global_enabled() to return huge order bitmap
Change the shmem_huge_global_enabled() to return the suitable huge order
bitmap, and return 0 if huge pages are not allowed.  This is a preparation
for supporting various huge orders allocation of tmpfs in the following
patches.

No functional changes.

Link: https://lkml.kernel.org/r/9dce1cfad3e9c1587cf1a0ea782ddbebd0e92984.1732779148.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-13 22:40:36 -08:00
Chuck Lever
d7bde4f27c
Revert "libfs: Add simple_offset_empty()"
simple_empty() and simple_offset_empty() perform the same task.
The latter's use as a canary to find bugs has not found any new
issues. A subsequent patch will remove the use of the mtree for
iterating directory contents, so revert back to using a similar
mechanism for determining whether a directory is indeed empty.

Only one such mechanism is ever needed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20241228175522.1854234-3-cel@kernel.org
Reviewed-by: Yang Erkun <yangerkun@huawei.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-01-04 10:15:51 +01:00
Baolin Wang
d77b90d2b2 mm: shmem: fix the update of 'shmem_falloc->nr_unswapped'
The 'shmem_falloc->nr_unswapped' is used to record how many writepage
refused to swap out because fallocate() is allocating, but after shmem
supports large folio swap out, the update of 'shmem_falloc->nr_unswapped'
does not use the correct number of pages in the large folio, which may
lead to fallocate() not exiting as soon as possible.

Anyway, this is found through code inspection, and I am not sure whether
it would actually cause serious issues.

Link: https://lkml.kernel.org/r/f66a0119d0564c2c37c84f045835b870d1b2196f.1734593154.git.baolin.wang@linux.alibaba.com
Fixes: 809bc86517cc ("mm: shmem: support large folio swap out")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-12-30 17:59:10 -08:00
Baolin Wang
d0e6983a6d mm: shmem: fix incorrect index alignment for within_size policy
With enabling the shmem per-size within_size policy, using an incorrect
'order' size to round_up() the index can lead to incorrect i_size checks,
resulting in an inappropriate large orders being returned.

Changing to use '1 << order' to round_up() the index to fix this issue. 
Additionally, adding an 'aligned_index' variable to avoid affecting the
index checks.

Link: https://lkml.kernel.org/r/77d8ef76a7d3d646e9225e9af88a76549a68aab1.1734593154.git.baolin.wang@linux.alibaba.com
Fixes: e7a2ab7b3bb5 ("mm: shmem: add mTHP support for anonymous shmem")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-12-30 17:59:09 -08:00
Mateusz Guzik
657e726e0c
tmpfs: use inode_set_cached_link()
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20241120112037.822078-4-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-12-22 11:29:51 +01:00
Hugh Dickins
dad2dc9c92 mm: shmem: fix ShmemHugePages at swapout
/proc/meminfo ShmemHugePages has been showing overlarge amounts (more than
Shmem) after swapping out THPs: we forgot to update NR_SHMEM_THPS.

Add shmem_update_stats(), to avoid repetition, and risk of making that
mistake again: the call from shmem_delete_from_page_cache() is the bugfix;
the call from shmem_replace_folio() is reassuring, but not really a bugfix
(replace corrects misplaced swapin readahead, but huge swapin readahead
would be a mistake).

Link: https://lkml.kernel.org/r/5ba477c8-a569-70b5-923e-09ab221af45b@google.com
Fixes: 809bc86517cc ("mm: shmem: support large folio swap out")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-12-18 19:04:42 -08:00
Linus Torvalds
5c00ff742b - The series "zram: optimal post-processing target selection" from
Sergey Senozhatsky improves zram's post-processing selection algorithm.
   This leads to improved memory savings.
 
 - Wei Yang has gone to town on the mapletree code, contributing several
   series which clean up the implementation:
 
 	- "refine mas_mab_cp()"
 	- "Reduce the space to be cleared for maple_big_node"
 	- "maple_tree: simplify mas_push_node()"
 	- "Following cleanup after introduce mas_wr_store_type()"
 	- "refine storing null"
 
 - The series "selftests/mm: hugetlb_fault_after_madv improvements" from
   David Hildenbrand fixes this selftest for s390.
 
 - The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng
   implements some rationaizations and cleanups in the page mapping code.
 
 - The series "mm: optimize shadow entries removal" from Shakeel Butt
   optimizes the file truncation code by speeding up the handling of shadow
   entries.
 
 - The series "Remove PageKsm()" from Matthew Wilcox completes the
   migration of this flag over to being a folio-based flag.
 
 - The series "Unify hugetlb into arch_get_unmapped_area functions" from
   Oscar Salvador implements a bunch of consolidations and cleanups in the
   hugetlb code.
 
 - The series "Do not shatter hugezeropage on wp-fault" from Dev Jain
   takes away the wp-fault time practice of turning a huge zero page into
   small pages.  Instead we replace the whole thing with a THP.  More
   consistent cleaner and potentiall saves a large number of pagefaults.
 
 - The series "percpu: Add a test case and fix for clang" from Andy
   Shevchenko enhances and fixes the kernel's built in percpu test code.
 
 - The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett
   optimizes mremap() by avoiding doing things which we didn't need to do.
 
 - The series "Improve the tmpfs large folio read performance" from
   Baolin Wang teaches tmpfs to copy data into userspace at the folio size
   rather than as individual pages.  A 20% speedup was observed.
 
 - The series "mm/damon/vaddr: Fix issue in
   damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON splitting.
 
 - The series "memcg-v1: fully deprecate charge moving" from Shakeel Butt
   removes the long-deprecated memcgv2 charge moving feature.
 
 - The series "fix error handling in mmap_region() and refactor" from
   Lorenzo Stoakes cleanup up some of the mmap() error handling and
   addresses some potential performance issues.
 
 - The series "x86/module: use large ROX pages for text allocations" from
   Mike Rapoport teaches x86 to use large pages for read-only-execute
   module text.
 
 - The series "page allocation tag compression" from Suren Baghdasaryan
   is followon maintenance work for the new page allocation profiling
   feature.
 
 - The series "page->index removals in mm" from Matthew Wilcox remove
   most references to page->index in mm/.  A slow march towards shrinking
   struct page.
 
 - The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs
   interface tests" from Andrew Paniakin performs maintenance work for
   DAMON's self testing code.
 
 - The series "mm: zswap swap-out of large folios" from Kanchana Sridhar
   improves zswap's batching of compression and decompression.  It is a
   step along the way towards using Intel IAA hardware acceleration for
   this zswap operation.
 
 - The series "kasan: migrate the last module test to kunit" from
   Sabyrzhan Tasbolatov completes the migration of the KASAN built-in tests
   over to the KUnit framework.
 
 - The series "implement lightweight guard pages" from Lorenzo Stoakes
   permits userapace to place fault-generating guard pages within a single
   VMA, rather than requiring that multiple VMAs be created for this.
   Improved efficiencies for userspace memory allocators are expected.
 
 - The series "memcg: tracepoint for flushing stats" from JP Kobryn uses
   tracepoints to provide increased visibility into memcg stats flushing
   activity.
 
 - The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky
   fixes a zram buglet which potentially affected performance.
 
 - The series "mm: add more kernel parameters to control mTHP" from
   Maíra Canal enhances our ability to control/configuremultisize THP from
   the kernel boot command line.
 
 - The series "kasan: few improvements on kunit tests" from Sabyrzhan
   Tasbolatov has a couple of fixups for the KASAN KUnit tests.
 
 - The series "mm/list_lru: Split list_lru lock into per-cgroup scope"
   from Kairui Song optimizes list_lru memory utilization when lockdep is
   enabled.
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Merge tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - The series "zram: optimal post-processing target selection" from
   Sergey Senozhatsky improves zram's post-processing selection
   algorithm. This leads to improved memory savings.

 - Wei Yang has gone to town on the mapletree code, contributing several
   series which clean up the implementation:
	- "refine mas_mab_cp()"
	- "Reduce the space to be cleared for maple_big_node"
	- "maple_tree: simplify mas_push_node()"
	- "Following cleanup after introduce mas_wr_store_type()"
	- "refine storing null"

 - The series "selftests/mm: hugetlb_fault_after_madv improvements" from
   David Hildenbrand fixes this selftest for s390.

 - The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng
   implements some rationaizations and cleanups in the page mapping
   code.

 - The series "mm: optimize shadow entries removal" from Shakeel Butt
   optimizes the file truncation code by speeding up the handling of
   shadow entries.

 - The series "Remove PageKsm()" from Matthew Wilcox completes the
   migration of this flag over to being a folio-based flag.

 - The series "Unify hugetlb into arch_get_unmapped_area functions" from
   Oscar Salvador implements a bunch of consolidations and cleanups in
   the hugetlb code.

 - The series "Do not shatter hugezeropage on wp-fault" from Dev Jain
   takes away the wp-fault time practice of turning a huge zero page
   into small pages. Instead we replace the whole thing with a THP. More
   consistent cleaner and potentiall saves a large number of pagefaults.

 - The series "percpu: Add a test case and fix for clang" from Andy
   Shevchenko enhances and fixes the kernel's built in percpu test code.

 - The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett
   optimizes mremap() by avoiding doing things which we didn't need to
   do.

 - The series "Improve the tmpfs large folio read performance" from
   Baolin Wang teaches tmpfs to copy data into userspace at the folio
   size rather than as individual pages. A 20% speedup was observed.

 - The series "mm/damon/vaddr: Fix issue in
   damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON
   splitting.

 - The series "memcg-v1: fully deprecate charge moving" from Shakeel
   Butt removes the long-deprecated memcgv2 charge moving feature.

 - The series "fix error handling in mmap_region() and refactor" from
   Lorenzo Stoakes cleanup up some of the mmap() error handling and
   addresses some potential performance issues.

 - The series "x86/module: use large ROX pages for text allocations"
   from Mike Rapoport teaches x86 to use large pages for
   read-only-execute module text.

 - The series "page allocation tag compression" from Suren Baghdasaryan
   is followon maintenance work for the new page allocation profiling
   feature.

 - The series "page->index removals in mm" from Matthew Wilcox remove
   most references to page->index in mm/. A slow march towards shrinking
   struct page.

 - The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs
   interface tests" from Andrew Paniakin performs maintenance work for
   DAMON's self testing code.

 - The series "mm: zswap swap-out of large folios" from Kanchana Sridhar
   improves zswap's batching of compression and decompression. It is a
   step along the way towards using Intel IAA hardware acceleration for
   this zswap operation.

 - The series "kasan: migrate the last module test to kunit" from
   Sabyrzhan Tasbolatov completes the migration of the KASAN built-in
   tests over to the KUnit framework.

 - The series "implement lightweight guard pages" from Lorenzo Stoakes
   permits userapace to place fault-generating guard pages within a
   single VMA, rather than requiring that multiple VMAs be created for
   this. Improved efficiencies for userspace memory allocators are
   expected.

 - The series "memcg: tracepoint for flushing stats" from JP Kobryn uses
   tracepoints to provide increased visibility into memcg stats flushing
   activity.

 - The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky
   fixes a zram buglet which potentially affected performance.

 - The series "mm: add more kernel parameters to control mTHP" from
   Maíra Canal enhances our ability to control/configuremultisize THP
   from the kernel boot command line.

 - The series "kasan: few improvements on kunit tests" from Sabyrzhan
   Tasbolatov has a couple of fixups for the KASAN KUnit tests.

 - The series "mm/list_lru: Split list_lru lock into per-cgroup scope"
   from Kairui Song optimizes list_lru memory utilization when lockdep
   is enabled.

* tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (215 commits)
  cma: enforce non-zero pageblock_order during cma_init_reserved_mem()
  mm/kfence: add a new kunit test test_use_after_free_read_nofault()
  zram: fix NULL pointer in comp_algorithm_show()
  memcg/hugetlb: add hugeTLB counters to memcg
  vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event
  mm: mmap_lock: check trace_mmap_lock_$type_enabled() instead of regcount
  zram: ZRAM_DEF_COMP should depend on ZRAM
  MAINTAINERS/MEMORY MANAGEMENT: add document files for mm
  Docs/mm/damon: recommend academic papers to read and/or cite
  mm: define general function pXd_init()
  kmemleak: iommu/iova: fix transient kmemleak false positive
  mm/list_lru: simplify the list_lru walk callback function
  mm/list_lru: split the lock to per-cgroup scope
  mm/list_lru: simplify reparenting and initial allocation
  mm/list_lru: code clean up for reparenting
  mm/list_lru: don't export list_lru_add
  mm/list_lru: don't pass unnecessary key parameters
  kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller
  kasan: change kasan_atomics kunit test as KUNIT_CASE_SLOW
  kasan: use EXPORT_SYMBOL_IF_KUNIT to export symbols
  ...
2024-11-23 09:58:07 -08:00
Linus Torvalds
7956186e75 vfs-6.13.tmpfs
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Merge tag 'vfs-6.13.tmpfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull tmpfs case folding updates from Christian Brauner:
 "This adds case-insensitive support for tmpfs.

  The work contained in here adds support for case-insensitive file
  names lookups in tmpfs. The main difference from other casefold
  filesystems is that tmpfs has no information on disk, just on RAM, so
  we can't use mkfs to create a case-insensitive tmpfs. For this
  implementation, there's a mount option for casefolding. The rest of
  the patchset follows a similar approach as ext4 and f2fs.

  The use case for this feature is similar to the use case for ext4, to
  better support compatibility layers (like Wine), particularly in
  combination with sandboxing/container tools (like Flatpak).

  Those containerization tools can share a subset of the host filesystem
  with an application. In the container, the root directory and any
  parent directories required for a shared directory are on tmpfs, with
  the shared directories bind-mounted into the container's view of the
  filesystem.

  If the host filesystem is using case-insensitive directories, then the
  application can do lookups inside those directories in a
  case-insensitive way, without this needing to be implemented in
  user-space. However, if the host is only sharing a subset of a
  case-insensitive directory with the application, then the parent
  directories of the mount point will be part of the container's root
  tmpfs. When the application tries to do case-insensitive lookups of
  those parent directories on a case-sensitive tmpfs, the lookup will
  fail"

* tag 'vfs-6.13.tmpfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  tmpfs: Initialize sysfs during tmpfs init
  tmpfs: Fix type for sysfs' casefold attribute
  libfs: Fix kernel-doc warning in generic_ci_validate_strict_name
  docs: tmpfs: Add casefold options
  tmpfs: Expose filesystem features via sysfs
  tmpfs: Add flag FS_CASEFOLD_FL support for tmpfs dirs
  tmpfs: Add casefold lookup support
  libfs: Export generic_ci_ dentry functions
  unicode: Recreate utf8_parse_version()
  unicode: Export latest available UTF-8 version number
  ext4: Use generic_ci_validate_strict_name helper
  libfs: Create the helper function generic_ci_validate_strict_name()
2024-11-18 11:05:26 -08:00
Linus Torvalds
6ac81fd55e vfs-6.13.mgtime
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Merge tag 'vfs-6.13.mgtime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs multigrain timestamps from Christian Brauner:
 "This is another try at implementing multigrain timestamps. This time
  with significant help from the timekeeping maintainers to reduce the
  performance impact.

  Thomas provided a base branch that contains the required timekeeping
  interfaces for the VFS. It serves as the base for the multi-grain
  timestamp work:

   - Multigrain timestamps allow the kernel to use fine-grained
     timestamps when an inode's attributes is being actively observed
     via ->getattr(). With this support, it's possible for a file to get
     a fine-grained timestamp, and another modified after it to get a
     coarse-grained stamp that is earlier than the fine-grained time. If
     this happens then the files can appear to have been modified in
     reverse order, which breaks VFS ordering guarantees.

     To prevent this, a floor value is maintained for multigrain
     timestamps. Whenever a fine-grained timestamp is handed out, record
     it, and when later coarse-grained stamps are handed out, ensure
     they are not earlier than that value. If the coarse-grained
     timestamp is earlier than the fine-grained floor, return the floor
     value instead.

     The timekeeper changes add a static singleton atomic64_t into
     timekeeper.c that is used to keep track of the latest fine-grained
     time ever handed out. This is tracked as a monotonic ktime_t value
     to ensure that it isn't affected by clock jumps. Because it is
     updated at different times than the rest of the timekeeper object,
     the floor value is managed independently of the timekeeper via a
     cmpxchg() operation, and sits on its own cacheline.

     Two new public timekeeper interfaces are added:

      (1) ktime_get_coarse_real_ts64_mg() fills a timespec64 with the
          later of the coarse-grained clock and the floor time

      (2) ktime_get_real_ts64_mg() gets the fine-grained clock value,
          and tries to swap it into the floor. A timespec64 is filled
          with the result.

   - The VFS has always used coarse-grained timestamps when updating the
     ctime and mtime after a change. This has the benefit of allowing
     filesystems to optimize away a lot metadata updates, down to around
     1 per jiffy, even when a file is under heavy writes.

     Unfortunately, this has always been an issue when we're exporting
     via NFSv3, which relies on timestamps to validate caches. A lot of
     changes can happen in a jiffy, so timestamps aren't sufficient to
     help the client decide when to invalidate the cache. Even with
     NFSv4, a lot of exported filesystems don't properly support a
     change attribute and are subject to the same problems with
     timestamp granularity. Other applications have similar issues with
     timestamps (e.g backup applications).

     If we were to always use fine-grained timestamps, that would
     improve the situation, but that becomes rather expensive, as the
     underlying filesystem would have to log a lot more metadata
     updates.

     This adds a way to only use fine-grained timestamps when they are
     being actively queried. Use the (unused) top bit in
     inode->i_ctime_nsec as a flag that indicates whether the current
     timestamps have been queried via stat() or the like. When it's set,
     we allow the kernel to use a fine-grained timestamp iff it's
     necessary to make the ctime show a different value.

     This solves the problem of being able to distinguish the timestamp
     between updates, but introduces a new problem: it's now possible
     for a file being changed to get a fine-grained timestamp. A file
     that is altered just a bit later can then get a coarse-grained one
     that appears older than the earlier fine-grained time. This
     violates timestamp ordering guarantees.

     This is where the earlier mentioned timkeeping interfaces help. A
     global monotonic atomic64_t value is kept that acts as a timestamp
     floor. When we go to stamp a file, we first get the latter of the
     current floor value and the current coarse-grained time. If the
     inode ctime hasn't been queried then we just attempt to stamp it
     with that value.

     If it has been queried, then first see whether the current coarse
     time is later than the existing ctime. If it is, then we accept
     that value. If it isn't, then we get a fine-grained time and try to
     swap that into the global floor. Whether that succeeds or fails, we
     take the resulting floor time, convert it to realtime and try to
     swap that into the ctime.

     We take the result of the ctime swap whether it succeeds or fails,
     since either is just as valid.

     Filesystems can opt into this by setting the FS_MGTIME fstype flag.
     Others should be unaffected (other than being subject to the same
     floor value as multigrain filesystems)"

* tag 'vfs-6.13.mgtime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: reduce pointer chasing in is_mgtime() test
  tmpfs: add support for multigrain timestamps
  btrfs: convert to multigrain timestamps
  ext4: switch to multigrain timestamps
  xfs: switch to multigrain timestamps
  Documentation: add a new file documenting multigrain timestamps
  fs: add percpu counters for significant multigrain timestamp events
  fs: tracepoints around multigrain timestamp events
  fs: handle delegated timestamps in setattr_copy_mgtime
  timekeeping: Add percpu counter for tracking floor swap events
  timekeeping: Add interfaces for handling timestamps with a floor value
  fs: have setattr_copy handle multigrain timestamps appropriately
  fs: add infrastructure for multigrain timestamps
2024-11-18 09:15:39 -08:00
Andrew Morton
d1aa0c0429 mm: revert "mm: shmem: fix data-race in shmem_getattr()"
Revert d949d1d14fa2 ("mm: shmem: fix data-race in shmem_getattr()") as
suggested by Chuck [1].  It is causing deadlocks when accessing tmpfs over
NFS.

As Hugh commented, "added just to silence a syzbot sanitizer splat: added
where there has never been any practical problem".

Link: https://lkml.kernel.org/r/ZzdxKF39VEmXSSyN@tissot.1015granger.net [1]
Fixes: d949d1d14fa2 ("mm: shmem: fix data-race in shmem_getattr()")
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Jeongjun Park <aha310510@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-16 15:30:32 -08:00
Maíra Canal
24f9cd195f mm: shmem: override mTHP shmem default with a kernel parameter
Add the ``thp_shmem=`` kernel command line to allow specifying the default
policy of each supported shmem hugepage size.  The kernel parameter
accepts the following format:

thp_shmem=<size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy>

For example,

thp_shmem=16K-64K:always;128K,512K:inherit;256K:advise;1M-2M:never;4M-8M:within_size

Some GPUs may benefit from using huge pages.  Since DRM GEM uses shmem to
allocate anonymous pageable memory, it's essential to control the huge
page allocation policy for the internal shmem mount.  This control can be
achieved through the ``transparent_hugepage_shmem=`` parameter.

Beyond just setting the allocation policy, it's crucial to have granular
control over the size of huge pages that can be allocated.  The GPU may
support only specific huge page sizes, and allocating pages larger/smaller
than those sizes would be ineffective.

Link: https://lkml.kernel.org/r/20241101165719.1074234-6-mcanal@igalia.com
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-11 13:09:43 -08:00
Maíra Canal
9490428111 mm: shmem: control THP support through the kernel command line
Patch series "mm: add more kernel parameters to control mTHP", v5.

This series introduces four patches related to the kernel parameters
controlling mTHP and a fifth patch replacing `strcpy()` for `strscpy()` in
the file `mm/huge_memory.c`.

The first patch is a straightforward documentation update, correcting the
format of the kernel parameter ``thp_anon=``.

The second, third, and fourth patches focus on controlling THP support for
shmem via the kernel command line.  The second patch introduces a
parameter to control the global default huge page allocation policy for
the internal shmem mount.  The third patch moves a piece of code to a
shared header to ease the implementation of the fourth patch.  Finally,
the fourth patch implements a parameter similar to ``thp_anon=``, but for
shmem.

The goal of these changes is to simplify the configuration of systems that
rely on mTHP support for shmem.  For instance, a platform with a GPU that
benefits from huge pages may want to enable huge pages for shmem.  Having
these kernel parameters streamlines the configuration process and ensures
consistency across setups.


This patch (of 4):

Add a new kernel command line to control the hugepage allocation policy
for the internal shmem mount, ``transparent_hugepage_shmem``. The
parameter is similar to ``transparent_hugepage`` and has the following
format:

transparent_hugepage_shmem=<policy>

where ``<policy>`` is one of the seven valid policies available for
shmem.

Configuring the default huge page allocation policy for the internal
shmem mount can be beneficial for DRM GPU drivers. Just as CPU
architectures, GPUs can also take advantage of huge pages, but this is
possible only if DRM GEM objects are backed by huge pages.

Since GEM uses shmem to allocate anonymous pageable memory, having control
over the default huge page allocation policy allows for the exploration of
huge pages use on GPUs that rely on GEM objects backed by shmem.

Link: https://lkml.kernel.org/r/20241101165719.1074234-2-mcanal@igalia.com
Link: https://lkml.kernel.org/r/20241101165719.1074234-4-mcanal@igalia.com
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: dri-devel@lists.freedesktop.org
Cc: Hugh Dickins <hughd@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: kernel-dev@igalia.com
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-11 13:09:43 -08:00
Baolin Wang
729881ffd3 mm: shmem: fallback to page size splice if large folio has poisoned pages
The tmpfs has already supported the PMD-sized large folios, and splice()
can not read any pages if the large folio has a poisoned page, which is
not good as Matthew pointed out in a previous email[1]:

"so if we have hwpoison set on one page in a folio, we now can't read
bytes from any page in the folio?  That seems like we've made a bad
situation worse."

Thus add a fallback to the PAGE_SIZE splice() still allows reading normal
pages if the large folio has hwpoisoned pages.

[1] https://lore.kernel.org/all/Zw_d0EVAJkpNJEbA@casper.infradead.org/

[baolin.wang@linux.alibaba.com: code layout cleaup, per dhowells]
  Link: https://lkml.kernel.org/r/32dd938c-3531-49f7-93e4-b7ff21fec569@linux.alibaba.com
Link: https://lkml.kernel.org/r/e3737fbd5366c4de4337bf5f2044817e77a5235b.1729915173.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-06 20:11:18 -08:00
Baolin Wang
a284cb8472 mm: shmem: improve the tmpfs large folio read performance
tmpfs already supports PMD-sized large folios, but the tmpfs read
operation still performs copying at PAGE_SIZE granularity, which is
unreasonable.  This patch changes tmpfs to copy data at folio granularity,
which can improve the read performance, as well as changing to use folio
related functions.

Moreover, if a large folio has a subpage that is hwpoisoned, it will
still fall back to page granularity copying.

Use 'fio bs=64k' to read a 1G tmpfs file populated with 2M THPs, and I can
see about 20% performance improvement, and no regression with bs=4k.
Before the patch:
READ: bw=10.0GiB/s

After the patch:
READ: bw=12.0GiB/s

Link: https://lkml.kernel.org/r/2129a21a5b9f77d3bb7ddec152c009ce7c5653c4.1729218573.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-06 20:11:17 -08:00
Baolin Wang
f3650ef89b mm: shmem: update iocb->ki_pos directly to simplify tmpfs read logic
Patch series "Improve the tmpfs large folio read performance", v2.

tmpfs already supports PMD-sized large folios, but the tmpfs read
operation still performs copying at PAGE_SIZE granularity, which is not
perfect.  This patchset changes tmpfs to copy data at the folio
granularity, which can improve the read performance.

Use 'fio bs=64k' to read a 1G tmpfs file populated with 2M THPs, and I can
see about 20% performance improvement, and no regression with bs=4k.  I
also did some functional testing with the xfstests suite, and I did not
find any regressions with the following xfstests config:

  FSTYP=tmpfs
  export TEST_DIR=/mnt/tempfs_mnt
  export TEST_DEV=/mnt/tempfs_mnt
  export SCRATCH_MNT=/mnt/scratchdir
  export SCRATCH_DEV=/mnt/scratchdir


This patch (of 2):

Using iocb->ki_pos to check if the read bytes exceeds the file size and to
calculate the bytes to be read can help simplify the code logic. 
Meanwhile, this is also a preparation for improving tmpfs large folios
read performance in the following patch.

Link: https://lkml.kernel.org/r/cover.1729218573.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/e8863e289577e0dc1e365b5419bf2d1c9a24ae3d.1729218573.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-06 20:11:16 -08:00
Kefeng Wang
4a9a27fdf7 mm: shmem: remove __shmem_huge_global_enabled()
Remove __shmem_huge_global_enabled() since it as only one caller, and
remove repeated check of VM_NOHUGEPAGE/MMF_DISABLE_THP as they are checked
in shmem_allowable_huge_orders(), also remove unnecessary vma parameter.

Link: https://lkml.kernel.org/r/20241017141457.1169092-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-06 20:11:15 -08:00
Kefeng Wang
5a90c155de tmpfs: don't enable large folios if not supported
tmpfs can support large folios, but there are some configurable options
(mount options and runtime deny/force) to enable/disable large folio
allocation, so there is a performance issue when performing writes without
large folios.  The issue is similar to commit 4e527d5841e2 ("iomap: fault
in smaller chunks for non-large folio mappings").

Since 'deny' is for emergencies and 'force' is for testing, performance
issues should not be a problem in real production environments, so don't
call mapping_set_large_folios() in __shmem_get_inode() when large folio is
disabled with mount huge=never option (default policy).

Link: https://lkml.kernel.org/r/20241017141742.1169404-1-wangkefeng.wang@huawei.com
Fixes: 9aac777aaf94 ("filemap: Convert generic_perform_write() to support large folios")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-06 20:11:15 -08:00
André Almeida
65c481f308
tmpfs: Initialize sysfs during tmpfs init
Instead of using fs_initcall(), initialize sysfs with the rest of the
filesystem. This is the right way to do it because otherwise any error
during tmpfs_sysfs_init() would get silently ignored. It's also useful
if tmpfs' sysfs ever need to display runtime information.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241101164251.327884-4-andrealmeid@igalia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-11-06 11:22:21 +01:00
André Almeida
18d2f10f62
tmpfs: Fix type for sysfs' casefold attribute
DEVICE_STRING_ATTR_RO should be only used by device drivers since it
relies on `struct device` to use device_show_string() function. Using
this with non device code led to a kCFI violation:

> cat /sys/fs/tmpfs/features/casefold
[   70.558496] CFI failure at kobj_attr_show+0x2c/0x4c (target: device_show_string+0x0/0x38; expected type: 0xc527b809)

Like the other filesystems, fix this by manually declaring the attribute
using kobj_attribute() and writing a proper show() function.

Also, leave macros for anyone that need to expand tmpfs sysfs' with
more attributes.

Fixes: 5132f08bd332 ("tmpfs: Expose filesystem features via sysfs")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/lkml/20241031051822.GA2947788@thelio-3990X/
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241101164251.327884-3-andrealmeid@igalia.com
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-11-06 11:22:20 +01:00
Baolin Wang
d2d243df44 mm: shmem: fix khugepaged activation policy for shmem
Shmem has a separate interface (different from anonymous pages) to control
huge page allocation, that means shmem THP can be enabled while anonymous
THP is disabled.  However, in this case, khugepaged will not start to
collapse shmem THP, which is unreasonable.

To fix this issue, we should call start_stop_khugepaged() to activate or
deactivate the khugepaged thread when setting shmem mTHP interfaces. 
Moreover, add a new helper shmem_hpage_pmd_enabled() to help to check
whether shmem THP is enabled, which will determine if khugepaged should be
activated.

Link: https://lkml.kernel.org/r/9b9c6cbc4499bf44c6455367fd9e0f6036525680.1726978977.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reported-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-05 16:56:20 -08:00
Lorenzo Stoakes
5baf8b037d mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling
Currently MTE is permitted in two circumstances (desiring to use MTE
having been specified by the VM_MTE flag) - where MAP_ANONYMOUS is
specified, as checked by arch_calc_vm_flag_bits() and actualised by
setting the VM_MTE_ALLOWED flag, or if the file backing the mapping is
shmem, in which case we set VM_MTE_ALLOWED in shmem_mmap() when the mmap
hook is activated in mmap_region().

The function that checks that, if VM_MTE is set, VM_MTE_ALLOWED is also
set is the arm64 implementation of arch_validate_flags().

Unfortunately, we intend to refactor mmap_region() to perform this check
earlier, meaning that in the case of a shmem backing we will not have
invoked shmem_mmap() yet, causing the mapping to fail spuriously.

It is inappropriate to set this architecture-specific flag in general mm
code anyway, so a sensible resolution of this issue is to instead move the
check somewhere else.

We resolve this by setting VM_MTE_ALLOWED much earlier in do_mmap(), via
the arch_calc_vm_flag_bits() call.

This is an appropriate place to do this as we already check for the
MAP_ANONYMOUS case here, and the shmem file case is simply a variant of
the same idea - we permit RAM-backed memory.

This requires a modification to the arch_calc_vm_flag_bits() signature to
pass in a pointer to the struct file associated with the mapping, however
this is not too egregious as this is only used by two architectures anyway
- arm64 and parisc.

So this patch performs this adjustment and removes the unnecessary
assignment of VM_MTE_ALLOWED in shmem_mmap().

[akpm@linux-foundation.org: fix whitespace, per Catalin]
Link: https://lkml.kernel.org/r/ec251b20ba1964fb64cf1607d2ad80c47f3873df.1730224667.git.lorenzo.stoakes@oracle.com
Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Jann Horn <jannh@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-05 16:49:55 -08:00
Jeongjun Park
d949d1d14f mm: shmem: fix data-race in shmem_getattr()
I got the following KCSAN report during syzbot testing:

==================================================================
BUG: KCSAN: data-race in generic_fillattr / inode_set_ctime_current

write to 0xffff888102eb3260 of 4 bytes by task 6565 on cpu 1:
 inode_set_ctime_to_ts include/linux/fs.h:1638 [inline]
 inode_set_ctime_current+0x169/0x1d0 fs/inode.c:2626
 shmem_mknod+0x117/0x180 mm/shmem.c:3443
 shmem_create+0x34/0x40 mm/shmem.c:3497
 lookup_open fs/namei.c:3578 [inline]
 open_last_lookups fs/namei.c:3647 [inline]
 path_openat+0xdbc/0x1f00 fs/namei.c:3883
 do_filp_open+0xf7/0x200 fs/namei.c:3913
 do_sys_openat2+0xab/0x120 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1442
 x64_sys_call+0x1025/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

read to 0xffff888102eb3260 of 4 bytes by task 3498 on cpu 0:
 inode_get_ctime_nsec include/linux/fs.h:1623 [inline]
 inode_get_ctime include/linux/fs.h:1629 [inline]
 generic_fillattr+0x1dd/0x2f0 fs/stat.c:62
 shmem_getattr+0x17b/0x200 mm/shmem.c:1157
 vfs_getattr_nosec fs/stat.c:166 [inline]
 vfs_getattr+0x19b/0x1e0 fs/stat.c:207
 vfs_statx_path fs/stat.c:251 [inline]
 vfs_statx+0x134/0x2f0 fs/stat.c:315
 vfs_fstatat+0xec/0x110 fs/stat.c:341
 __do_sys_newfstatat fs/stat.c:505 [inline]
 __se_sys_newfstatat+0x58/0x260 fs/stat.c:499
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:499
 x64_sys_call+0x141f/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

value changed: 0x2755ae53 -> 0x27ee44d3

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3498 Comm: udevd Not tainted 6.11.0-rc6-syzkaller-00326-gd1f2d51b711a-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
==================================================================

When calling generic_fillattr(), if you don't hold read lock, data-race
will occur in inode member variables, which can cause unexpected
behavior.

Since there is no special protection when shmem_getattr() calls
generic_fillattr(), data-race occurs by functions such as shmem_unlink()
or shmem_mknod(). This can cause unexpected results, so commenting it out
is not enough.

Therefore, when calling generic_fillattr() from shmem_getattr(), it is
appropriate to protect the inode using inode_lock_shared() and
inode_unlock_shared() to prevent data-race.

Link: https://lkml.kernel.org/r/20240909123558.70229-1-aha310510@gmail.com
Fixes: 44a30220bc0a ("shmem: recalculate file inode when fstat")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Reported-by: syzbot <syzkaller@googlegroup.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-28 21:40:39 -07:00
André Almeida
5132f08bd3
tmpfs: Expose filesystem features via sysfs
Expose filesystem features through sysfs, so userspace can query if
tmpfs support casefold.

This follows the same setup as defined by ext4 and f2fs to expose
casefold support to userspace.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241021-tonyk-tmpfs-v8-8-f443d5814194@igalia.com
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-28 13:36:55 +01:00
André Almeida
5cd9aecbc7
tmpfs: Add flag FS_CASEFOLD_FL support for tmpfs dirs
Enable setting flag FS_CASEFOLD_FL for tmpfs directories, when tmpfs is
mounted with casefold support. A special check is need for this flag,
since it can't be set for non-empty directories.

Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241021-tonyk-tmpfs-v8-7-f443d5814194@igalia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-28 13:36:55 +01:00