Commit Graph

1369 Commits

Author SHA1 Message Date
Linus Torvalds
617a814f14 ALong with the usual shower of singleton patches, notable patch series in
this pull request are:
 
 "Align kvrealloc() with krealloc()" from Danilo Krummrich.  Adds
 consistency to the APIs and behaviour of these two core allocation
 functions.  This also simplifies/enables Rustification.
 
 "Some cleanups for shmem" from Baolin Wang.  No functional changes - mode
 code reuse, better function naming, logic simplifications.
 
 "mm: some small page fault cleanups" from Josef Bacik.  No functional
 changes - code cleanups only.
 
 "Various memory tiering fixes" from Zi Yan.  A small fix and a little
 cleanup.
 
 "mm/swap: remove boilerplate" from Yu Zhao.  Code cleanups and
 simplifications and .text shrinkage.
 
 "Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt.  This
 is a feature, it adds new feilds to /proc/vmstat such as
 
     $ grep kstack /proc/vmstat
     kstack_1k 3
     kstack_2k 188
     kstack_4k 11391
     kstack_8k 243
     kstack_16k 0
 
 which tells us that 11391 processes used 4k of stack while none at all
 used 16k.  Useful for some system tuning things, but partivularly useful
 for "the dynamic kernel stack project".
 
 "kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov.
 Teaches kmemleak to detect leaksage of percpu memory.
 
 "mm: memcg: page counters optimizations" from Roman Gushchin.  "3
 independent small optimizations of page counters".
 
 "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David
 Hildenbrand.  Improves PTE/PMD splitlock detection, makes powerpc/8xx work
 correctly by design rather than by accident.
 
 "mm: remove arch_make_page_accessible()" from David Hildenbrand.  Some
 folio conversions which make arch_make_page_accessible() unneeded.
 
 "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel.
 Cleans up and fixes our handling of the resetting of the cgroup/process
 peak-memory-use detector.
 
 "Make core VMA operations internal and testable" from Lorenzo Stoakes.
 Rationalizaion and encapsulation of the VMA manipulation APIs.  With a
 view to better enable testing of the VMA functions, even from a
 userspace-only harness.
 
 "mm: zswap: fixes for global shrinker" from Takero Funaki.  Fix issues in
 the zswap global shrinker, resulting in improved performance.
 
 "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao.  Fill in
 some missing info in /proc/zoneinfo.
 
 "mm: replace follow_page() by folio_walk" from David Hildenbrand.  Code
 cleanups and rationalizations (conversion to folio_walk()) resulting in
 the removal of follow_page().
 
 "improving dynamic zswap shrinker protection scheme" from Nhat Pham.  Some
 tuning to improve zswap's dynamic shrinker.  Significant reductions in
 swapin and improvements in performance are shown.
 
 "mm: Fix several issues with unaccepted memory" from Kirill Shutemov.
 Improvements to the new unaccepted memory feature,
 
 "mm/mprotect: Fix dax puds" from Peter Xu.  Implements mprotect on DAX
 PUDs.  This was missing, although nobody seems to have notied yet.
 
 "Introduce a store type enum for the Maple tree" from Sidhartha Kumar.
 Cleanups and modest performance improvements for the maple tree library
 code.
 
 "memcg: further decouple v1 code from v2" from Shakeel Butt.  Move more
 cgroup v1 remnants away from the v2 memcg code.
 
 "memcg: initiate deprecation of v1 features" from Shakeel Butt.  Adds
 various warnings telling users that memcg v1 features are deprecated.
 
 "mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li.
 Greatly improves the success rate of the mTHP swap allocation.
 
 "mm: introduce numa_memblks" from Mike Rapoport.  Moves various disparate
 per-arch implementations of numa_memblk code into generic code.
 
 "mm: batch free swaps for zap_pte_range()" from Barry Song.  Greatly
 improves the performance of munmap() of swap-filled ptes.
 
 "support large folio swap-out and swap-in for shmem" from Baolin Wang.
 With this series we no longer split shmem large folios into simgle-page
 folios when swapping out shmem.
 
 "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao.  Nice performance
 improvements and code reductions for gigantic folios.
 
 "support shmem mTHP collapse" from Baolin Wang.  Adds support for
 khugepaged's collapsing of shmem mTHP folios.
 
 "mm: Optimize mseal checks" from Pedro Falcato.  Fixes an mprotect()
 performance regression due to the addition of mseal().
 
 "Increase the number of bits available in page_type" from Matthew Wilcox.
 Increases the number of bits available in page_type!
 
 "Simplify the page flags a little" from Matthew Wilcox.  Many legacy page
 flags are now folio flags, so the page-based flags and their
 accessors/mutators can be removed.
 
 "mm: store zero pages to be swapped out in a bitmap" from Usama Arif.  An
 optimization which permits us to avoid writing/reading zero-filled zswap
 pages to backing store.
 
 "Avoid MAP_FIXED gap exposure" from Liam Howlett.  Fixes a race window
 which occurs when a MAP_FIXED operqtion is occurring during an unrelated
 vma tree walk.
 
 "mm: remove vma_merge()" from Lorenzo Stoakes.  Major rotorooting of the
 vma_merge() functionality, making ot cleaner, more testable and better
 tested.
 
 "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.  Minor
 fixups of DAMON selftests and kunit tests.
 
 "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.  Code
 cleanups and folio conversions.
 
 "Shmem mTHP controls and stats improvements" from Ryan Roberts.  Cleanups
 for shmem controls and stats.
 
 "mm: count the number of anonymous THPs per size" from Barry Song.  Expose
 additional anon THP stats to userspace for improved tuning.
 
 "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio
 conversions and removal of now-unused page-based APIs.
 
 "replace per-quota region priorities histogram buffer with per-context
 one" from SeongJae Park.  DAMON histogram rationalization.
 
 "Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae
 Park.  DAMON documentation updates.
 
 "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve
 related doc and warn" from Jason Wang: fixes usage of page allocator
 __GFP_NOFAIL and GFP_ATOMIC flags.
 
 "mm: split underused THPs" from Yu Zhao.  Improve THP=always policy - this
 was overprovisioning THPs in sparsely accessed memory areas.
 
 "zram: introduce custom comp backends API" frm Sergey Senozhatsky.  Add
 support for zram run-time compression algorithm tuning.
 
 "mm: Care about shadow stack guard gap when getting an unmapped area" from
 Mark Brown.  Fix up the various arch_get_unmapped_area() implementations
 to better respect guard areas.
 
 "Improve mem_cgroup_iter()" from Kinsey Ho.  Improve the reliability of
 mem_cgroup_iter() and various code cleanups.
 
 "mm: Support huge pfnmaps" from Peter Xu.  Extends the usage of huge
 pfnmap support.
 
 "resource: Fix region_intersects() vs add_memory_driver_managed()" from
 Huang Ying.  Fix a bug in region_intersects() for systems with CXL memory.
 
 "mm: hwpoison: two more poison recovery" from Kefeng Wang.  Teaches a
 couple more code paths to correctly recover from the encountering of
 poisoned memry.
 
 "mm: enable large folios swap-in support" from Barry Song.  Support the
 swapin of mTHP memory into appropriately-sized folios, rather than into
 single-page folios.
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Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Along with the usual shower of singleton patches, notable patch series
  in this pull request are:

   - "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
     consistency to the APIs and behaviour of these two core allocation
     functions. This also simplifies/enables Rustification.

   - "Some cleanups for shmem" from Baolin Wang. No functional changes -
     mode code reuse, better function naming, logic simplifications.

   - "mm: some small page fault cleanups" from Josef Bacik. No
     functional changes - code cleanups only.

   - "Various memory tiering fixes" from Zi Yan. A small fix and a
     little cleanup.

   - "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
     simplifications and .text shrinkage.

   - "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
     Butt. This is a feature, it adds new feilds to /proc/vmstat such as

       $ grep kstack /proc/vmstat
       kstack_1k 3
       kstack_2k 188
       kstack_4k 11391
       kstack_8k 243
       kstack_16k 0

     which tells us that 11391 processes used 4k of stack while none at
     all used 16k. Useful for some system tuning things, but
     partivularly useful for "the dynamic kernel stack project".

   - "kmemleak: support for percpu memory leak detect" from Pavel
     Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.

   - "mm: memcg: page counters optimizations" from Roman Gushchin. "3
     independent small optimizations of page counters".

   - "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
     David Hildenbrand. Improves PTE/PMD splitlock detection, makes
     powerpc/8xx work correctly by design rather than by accident.

   - "mm: remove arch_make_page_accessible()" from David Hildenbrand.
     Some folio conversions which make arch_make_page_accessible()
     unneeded.

   - "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
     Finkel. Cleans up and fixes our handling of the resetting of the
     cgroup/process peak-memory-use detector.

   - "Make core VMA operations internal and testable" from Lorenzo
     Stoakes. Rationalizaion and encapsulation of the VMA manipulation
     APIs. With a view to better enable testing of the VMA functions,
     even from a userspace-only harness.

   - "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
     issues in the zswap global shrinker, resulting in improved
     performance.

   - "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
     in some missing info in /proc/zoneinfo.

   - "mm: replace follow_page() by folio_walk" from David Hildenbrand.
     Code cleanups and rationalizations (conversion to folio_walk())
     resulting in the removal of follow_page().

   - "improving dynamic zswap shrinker protection scheme" from Nhat
     Pham. Some tuning to improve zswap's dynamic shrinker. Significant
     reductions in swapin and improvements in performance are shown.

   - "mm: Fix several issues with unaccepted memory" from Kirill
     Shutemov. Improvements to the new unaccepted memory feature,

   - "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
     DAX PUDs. This was missing, although nobody seems to have notied
     yet.

   - "Introduce a store type enum for the Maple tree" from Sidhartha
     Kumar. Cleanups and modest performance improvements for the maple
     tree library code.

   - "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
     more cgroup v1 remnants away from the v2 memcg code.

   - "memcg: initiate deprecation of v1 features" from Shakeel Butt.
     Adds various warnings telling users that memcg v1 features are
     deprecated.

   - "mm: swap: mTHP swap allocator base on swap cluster order" from
     Chris Li. Greatly improves the success rate of the mTHP swap
     allocation.

   - "mm: introduce numa_memblks" from Mike Rapoport. Moves various
     disparate per-arch implementations of numa_memblk code into generic
     code.

   - "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
     improves the performance of munmap() of swap-filled ptes.

   - "support large folio swap-out and swap-in for shmem" from Baolin
     Wang. With this series we no longer split shmem large folios into
     simgle-page folios when swapping out shmem.

   - "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
     performance improvements and code reductions for gigantic folios.

   - "support shmem mTHP collapse" from Baolin Wang. Adds support for
     khugepaged's collapsing of shmem mTHP folios.

   - "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
     performance regression due to the addition of mseal().

   - "Increase the number of bits available in page_type" from Matthew
     Wilcox. Increases the number of bits available in page_type!

   - "Simplify the page flags a little" from Matthew Wilcox. Many legacy
     page flags are now folio flags, so the page-based flags and their
     accessors/mutators can be removed.

   - "mm: store zero pages to be swapped out in a bitmap" from Usama
     Arif. An optimization which permits us to avoid writing/reading
     zero-filled zswap pages to backing store.

   - "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
     window which occurs when a MAP_FIXED operqtion is occurring during
     an unrelated vma tree walk.

   - "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
     the vma_merge() functionality, making ot cleaner, more testable and
     better tested.

   - "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
     Minor fixups of DAMON selftests and kunit tests.

   - "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
     Code cleanups and folio conversions.

   - "Shmem mTHP controls and stats improvements" from Ryan Roberts.
     Cleanups for shmem controls and stats.

   - "mm: count the number of anonymous THPs per size" from Barry Song.
     Expose additional anon THP stats to userspace for improved tuning.

   - "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
     folio conversions and removal of now-unused page-based APIs.

   - "replace per-quota region priorities histogram buffer with
     per-context one" from SeongJae Park. DAMON histogram
     rationalization.

   - "Docs/damon: update GitHub repo URLs and maintainer-profile" from
     SeongJae Park. DAMON documentation updates.

   - "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
     improve related doc and warn" from Jason Wang: fixes usage of page
     allocator __GFP_NOFAIL and GFP_ATOMIC flags.

   - "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
     This was overprovisioning THPs in sparsely accessed memory areas.

   - "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
     Add support for zram run-time compression algorithm tuning.

   - "mm: Care about shadow stack guard gap when getting an unmapped
     area" from Mark Brown. Fix up the various arch_get_unmapped_area()
     implementations to better respect guard areas.

   - "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
     of mem_cgroup_iter() and various code cleanups.

   - "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
     pfnmap support.

   - "resource: Fix region_intersects() vs add_memory_driver_managed()"
     from Huang Ying. Fix a bug in region_intersects() for systems with
     CXL memory.

   - "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
     a couple more code paths to correctly recover from the encountering
     of poisoned memry.

   - "mm: enable large folios swap-in support" from Barry Song. Support
     the swapin of mTHP memory into appropriately-sized folios, rather
     than into single-page folios"

* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
  zram: free secondary algorithms names
  uprobes: turn xol_area->pages[2] into xol_area->page
  uprobes: introduce the global struct vm_special_mapping xol_mapping
  Revert "uprobes: use vm_special_mapping close() functionality"
  mm: support large folios swap-in for sync io devices
  mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
  mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
  mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
  set_memory: add __must_check to generic stubs
  mm/vma: return the exact errno in vms_gather_munmap_vmas()
  memcg: cleanup with !CONFIG_MEMCG_V1
  mm/show_mem.c: report alloc tags in human readable units
  mm: support poison recovery from copy_present_page()
  mm: support poison recovery from do_cow_fault()
  resource, kunit: add test case for region_intersects()
  resource: make alloc_free_mem_region() works for iomem_resource
  mm: z3fold: deprecate CONFIG_Z3FOLD
  vfio/pci: implement huge_fault support
  mm/arm64: support large pfn mappings
  mm/x86: support large pfn mappings
  ...
2024-09-21 07:29:05 -07:00
Linus Torvalds
839c4f596f 12 hotfixes, 11 of which are cc:stable.
Four fixes for longstanding ocfs2 issues and the remainder address random
 MM things.
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Merge tag 'mm-hotfixes-stable-2024-09-19-00-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc hotfixes from Andrew Morton:
 "12 hotfixes, 11 of which are cc:stable.

  Four fixes for longstanding ocfs2 issues and the remainder address
  random MM things"

* tag 'mm-hotfixes-stable-2024-09-19-00-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/madvise: process_madvise() drop capability check if same mm
  mm/huge_memory: ensure huge_zero_folio won't have large_rmappable flag set
  mm/hugetlb.c: fix UAF of vma in hugetlb fault pathway
  mm: change vmf_anon_prepare() to __vmf_anon_prepare()
  resource: fix region_intersects() vs add_memory_driver_managed()
  zsmalloc: use unique zsmalloc caches names
  mm/damon/vaddr: protect vma traversal in __damon_va_thre_regions() with rcu read lock
  mm: vmscan.c: fix OOM on swap stress test
  ocfs2: cancel dqi_sync_work before freeing oinfo
  ocfs2: fix possible null-ptr-deref in ocfs2_set_buffer_uptodate
  ocfs2: remove unreasonable unlock in ocfs2_read_blocks
  ocfs2: fix null-ptr-deref when journal load failed.
2024-09-19 11:35:31 +02:00
Chuanhua Han
242d12c981 mm: support large folios swap-in for sync io devices
Currently, we have mTHP features, but unfortunately, without support for
large folio swap-ins, once these large folios are swapped out, they are
lost because mTHP swap is a one-way process.  The lack of mTHP swap-in
functionality prevents mTHP from being used on devices like Android that
heavily rely on swap.

This patch introduces mTHP swap-in support.  It starts from sync devices
such as zRAM.  This is probably the simplest and most common use case,
benefiting billions of Android phones and similar devices with minimal
implementation cost.  In this straightforward scenario, large folios are
always exclusive, eliminating the need to handle complex rmap and
swapcache issues.

It offers several benefits:
1. Enables bidirectional mTHP swapping, allowing retrieval of mTHP after
   swap-out and swap-in. Large folios in the buddy system are also
   preserved as much as possible, rather than being fragmented due
   to swap-in.

2. Eliminates fragmentation in swap slots and supports successful
   THP_SWPOUT.

   w/o this patch (Refer to the data from Chris's and Kairui's latest
   swap allocator optimization while running ./thp_swap_allocator_test
   w/o "-a" option [1]):

   ./thp_swap_allocator_test
   Iteration 1: swpout inc: 233, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 2: swpout inc: 131, swpout fallback inc: 101, Fallback percentage: 43.53%
   Iteration 3: swpout inc: 71, swpout fallback inc: 155, Fallback percentage: 68.58%
   Iteration 4: swpout inc: 55, swpout fallback inc: 168, Fallback percentage: 75.34%
   Iteration 5: swpout inc: 35, swpout fallback inc: 191, Fallback percentage: 84.51%
   Iteration 6: swpout inc: 25, swpout fallback inc: 199, Fallback percentage: 88.84%
   Iteration 7: swpout inc: 23, swpout fallback inc: 205, Fallback percentage: 89.91%
   Iteration 8: swpout inc: 9, swpout fallback inc: 219, Fallback percentage: 96.05%
   Iteration 9: swpout inc: 13, swpout fallback inc: 213, Fallback percentage: 94.25%
   Iteration 10: swpout inc: 12, swpout fallback inc: 216, Fallback percentage: 94.74%
   Iteration 11: swpout inc: 16, swpout fallback inc: 213, Fallback percentage: 93.01%
   Iteration 12: swpout inc: 10, swpout fallback inc: 210, Fallback percentage: 95.45%
   Iteration 13: swpout inc: 16, swpout fallback inc: 212, Fallback percentage: 92.98%
   Iteration 14: swpout inc: 12, swpout fallback inc: 212, Fallback percentage: 94.64%
   Iteration 15: swpout inc: 15, swpout fallback inc: 211, Fallback percentage: 93.36%
   Iteration 16: swpout inc: 15, swpout fallback inc: 200, Fallback percentage: 93.02%
   Iteration 17: swpout inc: 9, swpout fallback inc: 220, Fallback percentage: 96.07%

   w/ this patch (always 0%):
   Iteration 1: swpout inc: 948, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 2: swpout inc: 953, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 3: swpout inc: 950, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 4: swpout inc: 952, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 5: swpout inc: 950, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 6: swpout inc: 950, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 7: swpout inc: 947, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 8: swpout inc: 950, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 9: swpout inc: 950, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 10: swpout inc: 945, swpout fallback inc: 0, Fallback percentage: 0.00%
   Iteration 11: swpout inc: 947, swpout fallback inc: 0, Fallback percentage: 0.00%
   ...

3. With both mTHP swap-out and swap-in supported, we offer the option to enable
   zsmalloc compression/decompression with larger granularity[2]. The upcoming
   optimization in zsmalloc will significantly increase swap speed and improve
   compression efficiency. Tested by running 100 iterations of swapping 100MiB
   of anon memory, the swap speed improved dramatically:
                time consumption of swapin(ms)   time consumption of swapout(ms)
     lz4 4k                  45274                    90540
     lz4 64k                 22942                    55667
     zstdn 4k                85035                    186585
     zstdn 64k               46558                    118533

    The compression ratio also improved, as evaluated with 1 GiB of data:
     granularity   orig_data_size   compr_data_size
     4KiB-zstd      1048576000       246876055
     64KiB-zstd     1048576000       199763892

   Without mTHP swap-in, the potential optimizations in zsmalloc cannot be
   realized.

4. Even mTHP swap-in itself can reduce swap-in page faults by a factor
   of nr_pages. Swapping in content filled with the same data 0x11, w/o
   and w/ the patch for five rounds (Since the content is the same,
   decompression will be very fast. This primarily assesses the impact of
   reduced page faults):

  swp in bandwidth(bytes/ms)    w/o              w/
   round1                     624152          1127501
   round2                     631672          1127501
   round3                     620459          1139756
   round4                     606113          1139756
   round5                     624152          1152281
   avg                        621310          1137359      +83%

5. With both mTHP swap-out and swap-in supported, we offer the option to enable
   hardware accelerators(Intel IAA) to do parallel decompression with which
   Kanchana reported 7X improvement on zRAM read latency[3].

[1] https://lore.kernel.org/all/20240730-swap-allocator-v5-0-cb9c148b9297@kernel.org/
[2] https://lore.kernel.org/all/20240327214816.31191-1-21cnbao@gmail.com/
[3] https://lore.kernel.org/all/cover.1714581792.git.andre.glover@linux.intel.com/

Link: https://lkml.kernel.org/r/20240908232119.2157-4-21cnbao@gmail.com
Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
Co-developed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gao Xiang <xiang@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Cc: Kairui Song <ryncsn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:07:01 -07:00
Barry Song
325efb16da mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
With large folios swap-in, we might need to uncharge multiple entries all
together, add nr argument in mem_cgroup_swapin_uncharge_swap().

For the existing two users, just pass nr=1.

Link: https://lkml.kernel.org/r/20240908232119.2157-3-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: Chris Li <chrisl@kernel.org>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gao Xiang <xiang@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:07:01 -07:00
Kefeng Wang
658be46520 mm: support poison recovery from copy_present_page()
Similar to other poison recovery, use copy_mc_user_highpage() to avoid
potentially kernel panic during copy page in copy_present_page() from
fork, once copy failed due to hwpoison in source page, we need to break
out of copy in copy_pte_range() and release prealloc folio, so
copy_mc_user_highpage() is moved ahead before set *prealloc to NULL.

Link: https://lkml.kernel.org/r/20240906024201.1214712-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:07:00 -07:00
Kefeng Wang
aa549f923f mm: support poison recovery from do_cow_fault()
Patch series "mm: hwpoison: two more poison recovery".

One more CoW path to support poison recorvery in do_cow_fault(), and the
last copy_user_highpage() user is replaced to copy_mc_user_highpage() from
copy_present_page() during fork to support poison recorvery too.


This patch (of 2):

Like commit a873dfe103 ("mm, hwpoison: try to recover from copy-on
write faults"), there is another path which could crash because it does
not have recovery code where poison is consumed by the kernel in
do_cow_fault(), a crash calltrace shown below on old kernel, but it
could be happened in the lastest mainline code,

  CPU: 7 PID: 3248 Comm: mpi Kdump: loaded Tainted: G           OE     5.10.0 #1
  pc : copy_page+0xc/0xbc
  lr : copy_user_highpage+0x50/0x9c
  Call trace:
    copy_page+0xc/0xbc
    do_cow_fault+0x118/0x2bc
    do_fault+0x40/0x1a4
    handle_pte_fault+0x154/0x230
    __handle_mm_fault+0x1a8/0x38c
    handle_mm_fault+0xf0/0x250
    do_page_fault+0x184/0x454
    do_translation_fault+0xac/0xd4
    do_mem_abort+0x44/0xbc

Fix it by using copy_mc_user_highpage() to handle this case and return
VM_FAULT_HWPOISON for cow fault.

[wangkefeng.wang@huawei.com: unlock/put vmf->page, per Miaohe]
  Link: https://lkml.kernel.org/r/20240910021541.234300-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240906024201.1214712-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240906024201.1214712-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:07:00 -07:00
Peter Xu
b0a1c0d0ed mm: remove follow_pte()
follow_pte() users have been converted to follow_pfnmap*().  Remove the
API.

Link: https://lkml.kernel.org/r/20240826204353.2228736-17-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:06:59 -07:00
Peter Xu
b17269a51c mm/access_process_vm: use the new follow_pfnmap API
Use the new API that can understand huge pfn mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-16-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:06:59 -07:00
Peter Xu
6da8e9634b mm: new follow_pfnmap API
Introduce a pair of APIs to follow pfn mappings to get entry information. 
It's very similar to what follow_pte() does before, but different in that
it recognizes huge pfn mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-10-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:06:59 -07:00
Peter Xu
10d83d7781 mm/pagewalk: check pfnmap for folio_walk_start()
Teach folio_walk_start() to recognize special pmd/pud mappings, and fail
them properly as it means there's no folio backing them.

[peterx@redhat.com: remove some stale comments, per David]
  Link: https://lkml.kernel.org/r/20240829202237.2640288-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20240826204353.2228736-7-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:06:58 -07:00
Vishal Moola (Oracle)
2a058ab328 mm: change vmf_anon_prepare() to __vmf_anon_prepare()
Some callers of vmf_anon_prepare() may not want us to release the per-VMA
lock ourselves.  Rename vmf_anon_prepare() to __vmf_anon_prepare() and let
the callers drop the lock when desired.

Also, make vmf_anon_prepare() a wrapper that releases the per-VMA lock
itself for any callers that don't care.

This is in preparation to fix this bug reported by syzbot:
https://lore.kernel.org/linux-mm/00000000000067c20b06219fbc26@google.com/

Link: https://lkml.kernel.org/r/20240914194243.245-1-vishal.moola@gmail.com
Fixes: 9acad7ba3e ("hugetlb: use vmf_anon_prepare() instead of anon_vma_prepare()")
Reported-by: syzbot+2dab93857ee95f2eeb08@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/00000000000067c20b06219fbc26@google.com/
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 00:58:04 -07:00
Linus Torvalds
79a61cc3fc mm: avoid leaving partial pfn mappings around in error case
As Jann points out, PFN mappings are special, because unlike normal
memory mappings, there is no lifetime information associated with the
mapping - it is just a raw mapping of PFNs with no reference counting of
a 'struct page'.

That's all very much intentional, but it does mean that it's easy to
mess up the cleanup in case of errors.  Yes, a failed mmap() will always
eventually clean up any partial mappings, but without any explicit
lifetime in the page table mapping itself, it's very easy to do the
error handling in the wrong order.

In particular, it's easy to mistakenly free the physical backing store
before the page tables are actually cleaned up and (temporarily) have
stale dangling PTE entries.

To make this situation less error-prone, just make sure that any partial
pfn mapping is torn down early, before any other error handling.

Reported-and-tested-by: Jann Horn <jannh@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-09-12 12:10:00 -07:00
Ryan Roberts
246d3aa3e5 mm: cleanup count_mthp_stat() definition
Patch series "Shmem mTHP controls and stats improvements", v3.

This is a small series to tidy up the way the shmem controls and stats are
exposed.  These patches were previously part of the series at [2], but I
decided to split them out since they can go in independently.


This patch (of 2):

Let's move count_mthp_stat() so that it's always defined, even when THP is
disabled.  Previously uses of the function in files such as shmem.c, which
are compiled even when THP is disabled, required ugly THP ifdeferry.  With
this cleanup, we can remove those ifdefs and the function resolves to a
nop when THP is disabled.

I shortly plan to call count_mthp_stat() from more THP-invariant source
files.

Link: https://lkml.kernel.org/r/20240808111849.651867-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20240808111849.651867-2-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Barry Song <baohua@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-09 16:38:57 -07:00
Kaiyang Zhao
f77f0c7514 mm,memcg: provide per-cgroup counters for NUMA balancing operations
The ability to observe the demotion and promotion decisions made by the
kernel on a per-cgroup basis is important for monitoring and tuning
containerized workloads on machines equipped with tiered memory.

Different containers in the system may experience drastically different
memory tiering actions that cannot be distinguished from the global
counters alone.

For example, a container running a workload that has a much hotter memory
accesses will likely see more promotions and fewer demotions, potentially
depriving a colocated container of top tier memory to such an extent that
its performance degrades unacceptably.

For another example, some containers may exhibit longer periods between
data reuse, causing much more numa_hint_faults than numa_pages_migrated. 
In this case, tuning hot_threshold_ms may be appropriate, but the signal
can easily be lost if only global counters are available.

In the long term, we hope to introduce per-cgroup control of promotion and
demotion actions to implement memory placement policies in tiering.

This patch set adds seven counters to memory.stat in a cgroup:
numa_pages_migrated, numa_pte_updates, numa_hint_faults, pgdemote_kswapd,
pgdemote_khugepaged, pgdemote_direct and pgpromote_success.  pgdemote_*
and pgpromote_success are also available in memory.numa_stat.

count_memcg_events_mm() is added to count multiple event occurrences at
once, and get_mem_cgroup_from_folio() is added because we need to get a
reference to the memcg of a folio before it's migrated to track
numa_pages_migrated.  The accounting of PGDEMOTE_* is moved to
shrink_inactive_list() before being changed to per-cgroup.

[kaiyang2@cs.cmu.edu: add documentation of the memcg counters in cgroup-v2.rst]
  Link: https://lkml.kernel.org/r/20240814235122.252309-1-kaiyang2@cs.cmu.edu
Link: https://lkml.kernel.org/r/20240814174227.30639-1-kaiyang2@cs.cmu.edu
Signed-off-by: Kaiyang Zhao <kaiyang2@cs.cmu.edu>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-03 21:15:36 -07:00
Zi Yan
727d50a7e0 mm/migrate: move common code to numa_migrate_check (was numa_migrate_prep)
do_numa_page() and do_huge_pmd_numa_page() share a lot of common code.  To
reduce redundancy, move common code to numa_migrate_prep() and rename the
function to numa_migrate_check() to reflect its functionality.

Now do_huge_pmd_numa_page() also checks shared folios to set TNF_SHARED
flag.

Link: https://lkml.kernel.org/r/20240809145906.1513458-4-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:06 -07:00
Matthew Wilcox (Oracle)
94dc8bffd8 mm: return the folio from swapin_readahead
The unuse_pte_range() caller only wants the folio while do_swap_page()
wants both the page and the folio.  Since do_swap_page() already has logic
for handling both the folio and the page, move the folio-to-page logic
there.  This also lets us allocate larger folios in the SWP_SYNCHRONOUS_IO
path in future.

Link: https://lkml.kernel.org/r/20240807193734.1865400-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:05 -07:00
Jann Horn
17fe833b0d mm: fix (harmless) type confusion in lock_vma_under_rcu()
There is a (harmless) type confusion in lock_vma_under_rcu(): After
vma_start_read(), we have taken the VMA lock but don't know yet whether
the VMA has already been detached and scheduled for RCU freeing.  At this
point, ->vm_start and ->vm_end are accessed.

vm_area_struct contains a union such that ->vm_rcu uses the same memory as
->vm_start and ->vm_end; so accessing ->vm_start and ->vm_end of a
detached VMA is illegal and leads to type confusion between union members.

Fix it by reordering the vma->detached check above the address checks, and
document the rules for RCU readers accessing VMAs.

This will probably change the number of observed VMA_LOCK_MISS events
(since previously, trying to access a detached VMA whose ->vm_rcu has been
scheduled would bail out when checking the fault address against the
rcu_head members reinterpreted as VMA bounds).

Link: https://lkml.kernel.org/r/20240805-fix-vma-lock-type-confusion-v1-1-9f25443a9a71@google.com
Fixes: 50ee325372 ("mm: introduce lock_vma_under_rcu to be used from arch-specific code")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:03 -07:00
David Hildenbrand
3523a37e65 mm: provide vm_normal_(page|folio)_pmd() with CONFIG_PGTABLE_HAS_HUGE_LEAVES
Patch series "mm: replace follow_page() by folio_walk".

Looking into a way of moving the last folio_likely_mapped_shared() call in
add_folio_for_migration() under the PTL, I found myself removing
follow_page().  This paves the way for cleaning up all the FOLL_, follow_*
terminology to just be called "GUP" nowadays.

The new page table walker will lookup a mapped folio and return to the
caller with the PTL held, such that the folio cannot get unmapped
concurrently.  Callers can then conditionally decide whether they really
want to take a short-term folio reference or whether the can simply unlock
the PTL and be done with it.

folio_walk is similar to page_vma_mapped_walk(), except that we don't know
the folio we want to walk to and that we are only walking to exactly one
PTE/PMD/PUD.

folio_walk provides access to the pte/pmd/pud (and the referenced folio
page because things like KSM need that), however, as part of this series
no page table modifications are performed by users.

We might be able to convert some other walk_page_range() users that really
only walk to one address, such as DAMON with
damon_mkold_ops/damon_young_ops.  It might make sense to extend folio_walk
in the future to optionally fault in a folio (if applicable), such that we
can replace some get_user_pages() users that really only want to lookup a
single page/folio under PTL without unconditionally grabbing a folio
reference.

I have plans to extend the approach to a range walker that will try
batching various page table entries (not just folio pages) to be a better
replace for walk_page_range() -- and users will be able to opt in which
type of page table entries they want to process -- but that will require
more work and more thoughts.

KSM seems to work just fine (ksm_functional_tests selftests) and
move_pages seems to work (migration selftest).  I tested the leaf
implementation excessively using various hugetlb sizes (64K, 2M, 32M, 1G)
on arm64 using move_pages and did some more testing on x86-64.  Cross
compiled on a bunch of architectures.


This patch (of 11):

We want to make use of vm_normal_page_pmd() in generic page table walking
code where we might walk hugetlb folios that are mapped by PMDs even
without CONFIG_TRANSPARENT_HUGEPAGE.

So let's expose vm_normal_page_pmd() + vm_normal_folio_pmd() with
CONFIG_PGTABLE_HAS_HUGE_LEAVES.

Link: https://lkml.kernel.org/r/20240802155524.517137-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240802155524.517137-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:25:59 -07:00
Barry Song
9f101bef40 mm: swap: add nr argument in swapcache_prepare and swapcache_clear to support large folios
Right now, swapcache_prepare() and swapcache_clear() supports one entry
only, to support large folios, we need to handle multiple swap entries.

To optimize stack usage, we iterate twice in __swap_duplicate(): the first
time to verify that all entries are valid, and the second time to apply
the modifications to the entries.

Currently, we're using nr=1 for the existing users.

[v-songbaohua@oppo.com: clarify swap_count_continued and improve readability for  __swap_duplicate]
  Link: https://lkml.kernel.org/r/20240802071817.47081-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240730071339.107447-2-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Gao Xiang <xiang@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:25:56 -07:00
David Hildenbrand
394290cba9 mm: turn USE_SPLIT_PTE_PTLOCKS / USE_SPLIT_PTE_PTLOCKS into Kconfig options
Patch series "mm: split PTE/PMD PT table Kconfig cleanups+clarifications".

This series is a follow up to the fixes:
	"[PATCH v1 0/2] mm/hugetlb: fix hugetlb vs. core-mm PT locking"

When working on the fixes, I wondered why 8xx is fine (-> never uses split
PT locks) and how PT locking even works properly with PMD page table
sharing (-> always requires split PMD PT locks).

Let's improve the split PT lock detection, make hugetlb properly depend on
it and make 8xx bail out if it would ever get enabled by accident.

As an alternative to patch #3 we could extend the Kconfig
SPLIT_PTE_PTLOCKS option from patch #2 -- but enforcing it closer to the
code that actually implements it feels a bit nicer for documentation
purposes, and there is no need to actually disable it because it should
always be disabled (!SMP).

Did a bunch of cross-compilations to make sure that split PTE/PMD PT locks
are still getting used where we would expect them.

[1] https://lkml.kernel.org/r/20240725183955.2268884-1-david@redhat.com


This patch (of 3):

Let's clean that up a bit and prepare for depending on
CONFIG_SPLIT_PMD_PTLOCKS in other Kconfig options.

More cleanups would be reasonable (like the arch-specific "depends on" for
CONFIG_SPLIT_PTE_PTLOCKS), but we'll leave that for another day.

Link: https://lkml.kernel.org/r/20240726150728.3159964-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240726150728.3159964-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:25:51 -07:00
Zi Yan
2a28713a67 memory tiering: introduce folio_use_access_time() check
If memory tiering mode is on and a folio is not in the top tier memory,
folio's cpupid field is repurposed to store page access time.  Instead of
an open coded check, use a function to encapsulate the check.

Link: https://lkml.kernel.org/r/20240724130115.793641-3-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:25:47 -07:00
Zi Yan
40b760cfd4 mm/numa: no task_numa_fault() call if PTE is changed
When handling a numa page fault, task_numa_fault() should be called by a
process that restores the page table of the faulted folio to avoid
duplicated stats counting.  Commit b99a342d4f ("NUMA balancing: reduce
TLB flush via delaying mapping on hint page fault") restructured
do_numa_page() and did not avoid task_numa_fault() call in the second page
table check after a numa migration failure.  Fix it by making all
!pte_same() return immediately.

This issue can cause task_numa_fault() being called more than necessary
and lead to unexpected numa balancing results (It is hard to tell whether
the issue will cause positive or negative performance impact due to
duplicated numa fault counting).

Link: https://lkml.kernel.org/r/20240809145906.1513458-2-ziy@nvidia.com
Fixes: b99a342d4f ("NUMA balancing: reduce TLB flush via delaying mapping on hint page fault")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reported-by: "Huang, Ying" <ying.huang@intel.com>
Closes: https://lore.kernel.org/linux-mm/87zfqfw0yw.fsf@yhuang6-desk2.ccr.corp.intel.com/
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-08-15 22:16:15 -07:00
Ram Tummala
4cd7ba16a0 mm: fix old/young bit handling in the faulting path
Commit 3bd786f76d ("mm: convert do_set_pte() to set_pte_range()")
replaced do_set_pte() with set_pte_range() and that introduced a
regression in the following faulting path of non-anonymous vmas which
caused the PTE for the faulting address to be marked as old instead of
young.

handle_pte_fault()
  do_pte_missing()
    do_fault()
      do_read_fault() || do_cow_fault() || do_shared_fault()
        finish_fault()
          set_pte_range()

The polarity of prefault calculation is incorrect.  This leads to prefault
being incorrectly set for the faulting address.  The following check will
incorrectly mark the PTE old rather than young.  On some architectures
this will cause a double fault to mark it young when the access is
retried.

    if (prefault && arch_wants_old_prefaulted_pte())
        entry = pte_mkold(entry);

On a subsequent fault on the same address, the faulting path will see a
non NULL vmf->pte and instead of reaching the do_pte_missing() path, PTE
will then be correctly marked young in handle_pte_fault() itself.

Due to this bug, performance degradation in the fault handling path will
be observed due to unnecessary double faulting.

Link: https://lkml.kernel.org/r/20240710014539.746200-1-rtummala@nvidia.com
Fixes: 3bd786f76d ("mm: convert do_set_pte() to set_pte_range()")
Signed-off-by: Ram Tummala <rtummala@nvidia.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-26 14:33:09 -07:00
Linus Torvalds
7a3fad30fd Random number generator updates for Linux 6.11-rc1.
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Merge tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:
 "This adds getrandom() support to the vDSO.

  First, it adds a new kind of mapping to mmap(2), MAP_DROPPABLE, which
  lets the kernel zero out pages anytime under memory pressure, which
  enables allocating memory that never gets swapped to disk but also
  doesn't count as being mlocked.

  Then, the vDSO implementation of getrandom() is introduced in a
  generic manner and hooked into random.c.

  Next, this is implemented on x86. (Also, though it's not ready for
  this pull, somebody has begun an arm64 implementation already)

  Finally, two vDSO selftests are added.

  There are also two housekeeping cleanup commits"

* tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  MAINTAINERS: add random.h headers to RNG subsection
  random: note that RNDGETPOOL was removed in 2.6.9-rc2
  selftests/vDSO: add tests for vgetrandom
  x86: vdso: Wire up getrandom() vDSO implementation
  random: introduce generic vDSO getrandom() implementation
  mm: add MAP_DROPPABLE for designating always lazily freeable mappings
2024-07-24 10:29:50 -07:00
Jason A. Donenfeld
9651fcedf7 mm: add MAP_DROPPABLE for designating always lazily freeable mappings
The vDSO getrandom() implementation works with a buffer allocated with a
new system call that has certain requirements:

- It shouldn't be written to core dumps.
  * Easy: VM_DONTDUMP.
- It should be zeroed on fork.
  * Easy: VM_WIPEONFORK.

- It shouldn't be written to swap.
  * Uh-oh: mlock is rlimited.
  * Uh-oh: mlock isn't inherited by forks.

- It shouldn't reserve actual memory, but it also shouldn't crash when
  page faulting in memory if none is available
  * Uh-oh: VM_NORESERVE means segfaults.

It turns out that the vDSO getrandom() function has three really nice
characteristics that we can exploit to solve this problem:

1) Due to being wiped during fork(), the vDSO code is already robust to
   having the contents of the pages it reads zeroed out midway through
   the function's execution.

2) In the absolute worst case of whatever contingency we're coding for,
   we have the option to fallback to the getrandom() syscall, and
   everything is fine.

3) The buffers the function uses are only ever useful for a maximum of
   60 seconds -- a sort of cache, rather than a long term allocation.

These characteristics mean that we can introduce VM_DROPPABLE, which
has the following semantics:

a) It never is written out to swap.
b) Under memory pressure, mm can just drop the pages (so that they're
   zero when read back again).
c) It is inherited by fork.
d) It doesn't count against the mlock budget, since nothing is locked.
e) If there's not enough memory to service a page fault, it's not fatal,
   and no signal is sent.

This way, allocations used by vDSO getrandom() can use:

    VM_DROPPABLE | VM_DONTDUMP | VM_WIPEONFORK | VM_NORESERVE

And there will be no problem with OOMing, crashing on overcommitment,
using memory when not in use, not wiping on fork(), coredumps, or
writing out to swap.

In order to let vDSO getrandom() use this, expose these via mmap(2) as
MAP_DROPPABLE.

Note that this involves removing the MADV_FREE special case from
sort_folio(), which according to Yu Zhao is unnecessary and will simply
result in an extra call to shrink_folio_list() in the worst case. The
chunk removed reenables the swapbacked flag, which we don't want for
VM_DROPPABLE, and we can't conditionalize it here because there isn't a
vma reference available.

Finally, the provided self test ensures that this is working as desired.

Cc: linux-mm@kvack.org
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2024-07-19 20:22:12 +02:00
Christoph Hellwig
cd1e0dac3a mm: unexport vmf_insert_mixed_mkwrite
vmf_insert_mixed_mkwrite is only used by the built-in DAX code.

Link: https://lkml.kernel.org/r/20240702072327.1640911-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12 15:52:19 -07:00
Kefeng Wang
28bdacbcb3 mm: move memory_failure_queue() into copy_mc_[user]_highpage()
Patch series "mm: migrate: support poison recover from migrate folio", v5.

The folio migration is widely used in kernel, memory compaction, memory
hotplug, soft offline page, numa balance, memory demote/promotion, etc,
but once access a poisoned source folio when migrating, the kernel will
panic.

There is a mechanism in the kernel to recover from uncorrectable memory
errors, ARCH_HAS_COPY_MC(eg, Machine Check Safe Memory Copy on x86), which
is already used in NVDIMM or core-mm paths(eg, CoW, khugepaged, coredump,
ksm copy), see copy_mc_to_{user,kernel}, copy_mc_{user_}highpage callers.

This series of patches provide the recovery mechanism from folio copy for
the widely used folio migration.  Please note, because folio migration is
no guarantee of success, so we could chose to make folio migration
tolerant of memory failures, adding folio_mc_copy() which is a #MC
versions of folio_copy(), once accessing a poisoned source folio, we could
return error and make the folio migration fail, and this could avoid the
similar panic shown below.

  CPU: 1 PID: 88343 Comm: test_softofflin Kdump: loaded Not tainted 6.6.0
  pc : copy_page+0x10/0xc0
  lr : copy_highpage+0x38/0x50
  ...
  Call trace:
   copy_page+0x10/0xc0
   folio_copy+0x78/0x90
   migrate_folio_extra+0x54/0xa0
   move_to_new_folio+0xd8/0x1f0
   migrate_folio_move+0xb8/0x300
   migrate_pages_batch+0x528/0x788
   migrate_pages_sync+0x8c/0x258
   migrate_pages+0x440/0x528
   soft_offline_in_use_page+0x2ec/0x3c0
   soft_offline_page+0x238/0x310
   soft_offline_page_store+0x6c/0xc0
   dev_attr_store+0x20/0x40
   sysfs_kf_write+0x4c/0x68
   kernfs_fop_write_iter+0x130/0x1c8
   new_sync_write+0xa4/0x138
   vfs_write+0x238/0x2d8
   ksys_write+0x74/0x110


This patch (of 5):

There is a memory_failure_queue() call after copy_mc_[user]_highpage(),
see callers, eg, CoW/KSM page copy, it is used to mark the source page as
h/w poisoned and unmap it from other tasks, and the upcomming poison
recover from migrate folio will do the similar thing, so let's move the
memory_failure_queue() into the copy_mc_[user]_highpage() instead of
adding it into each user, this should also enhance the handling of
poisoned page in khugepaged.

Link: https://lkml.kernel.org/r/20240626085328.608006-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240626085328.608006-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-06 11:53:19 -07:00
David Hildenbrand
ee86814b05 mm/migrate: move NUMA hinting fault folio isolation + checks under PTL
Currently we always take a folio reference even if migration will not even
be tried or isolation failed, requiring us to grab+drop an additional
reference.

Further, we end up calling folio_likely_mapped_shared() while the folio
might have already been unmapped, because after we dropped the PTL, that
can easily happen.  We want to stop touching mapcounts and friends from
such context, and only call folio_likely_mapped_shared() while the folio
is still mapped: mapcount information is pretty much stale and unreliable
otherwise.

So let's move checks into numamigrate_isolate_folio(), rename that
function to migrate_misplaced_folio_prepare(), and call that function from
callsites where we call migrate_misplaced_folio(), but still with the PTL
held.

We can now stop taking temporary folio references, and really only take a
reference if folio isolation succeeded.  Doing the
folio_likely_mapped_shared() + folio isolation under PT lock is now
similar to how we handle MADV_PAGEOUT.

While at it, combine the folio_is_file_lru() checks.

[david@redhat.com: fix list_del() corruption]
  Link: https://lkml.kernel.org/r/8f85c31a-e603-4578-bf49-136dae0d4b69@redhat.com
  Link: https://lkml.kernel.org/r/20240626191129.658CFC32782@smtp.kernel.org
Link: https://lkml.kernel.org/r/20240620212935.656243-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Tested-by: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:26 -07:00
David Hildenbrand
4b88c23ab8 mm/migrate: make migrate_misplaced_folio() return 0 on success
Patch series "mm/migrate: move NUMA hinting fault folio isolation + checks
under PTL".


Let's just return 0 on success, which is less confusing.

...  especially because we got it wrong in the migrate.h stub where we
have "return -EAGAIN; /* can't migrate now */" instead of "return 0;". 
Likely this wrong return value doesn't currently matter, but it certainly
adds confusion.

We'll add migrate_misplaced_folio_prepare() next, where we want to use the
same "return 0 on success" approach, so let's just clean this up.

Link: https://lkml.kernel.org/r/20240620212935.656243-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240620212935.656243-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:26 -07:00
Kefeng Wang
2f9f085436 mm: memory: rename pages_per_huge_page to nr_pages
Since the callers are converted to use nr_pages naming, use it inside too.

Link: https://lkml.kernel.org/r/20240618091242.2140164-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:20 -07:00
Kefeng Wang
530dd9926d mm: memory: improve copy_user_large_folio()
Use nr_pages instead of pages_per_huge_page and move the address alignment
from copy_user_large_folio() into the callers since it is only needed when
we don't know which address will be accessed.

Link: https://lkml.kernel.org/r/20240618091242.2140164-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:20 -07:00
Kefeng Wang
5132633ee7 mm: memory: use folio in struct copy_subpage_arg
Directly use folio in struct copy_subpage_arg.

Link: https://lkml.kernel.org/r/20240618091242.2140164-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:20 -07:00
Kefeng Wang
78fefd04c1 mm: memory: convert clear_huge_page() to folio_zero_user()
Patch series "mm: improve clear and copy user folio", v2.

Some folio conversions.  An improvement is to move address alignment into
the caller as it is only needed if we don't know which address will be
accessed when clearing/copying user folios.


This patch (of 4):

Replace clear_huge_page() with folio_zero_user(), and take a folio
instead of a page. Directly get number of pages by folio_nr_pages()
to remove pages_per_huge_page argument, furthermore, move the address
alignment from folio_zero_user() to the callers since the alignment
is only needed when we don't know which address will be accessed.

Link: https://lkml.kernel.org/r/20240618091242.2140164-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240618091242.2140164-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:20 -07:00
Barry Song
9ae2feaced mm: use folio_add_new_anon_rmap() if folio_test_anon(folio)==false
For the !folio_test_anon(folio) case, we can now invoke
folio_add_new_anon_rmap() with the rmap flags set to either EXCLUSIVE or
non-EXCLUSIVE.  This action will suppress the VM_WARN_ON_FOLIO check
within __folio_add_anon_rmap() while initiating the process of bringing up
mTHP swapin.

 static __always_inline void __folio_add_anon_rmap(struct folio *folio,
                 struct page *page, int nr_pages, struct vm_area_struct *vma,
                 unsigned long address, rmap_t flags, enum rmap_level level)
 {
         ...
         if (unlikely(!folio_test_anon(folio))) {
                 VM_WARN_ON_FOLIO(folio_test_large(folio) &&
                                  level != RMAP_LEVEL_PMD, folio);
         }
         ...
 }

It also improves the code's readability.  Currently, all new anonymous
folios calling folio_add_anon_rmap_ptes() are order-0.  This ensures that
new folios cannot be partially exclusive; they are either entirely
exclusive or entirely shared.

A useful comment from Hugh's fix:

: Commit "mm: use folio_add_new_anon_rmap() if folio_test_anon(folio)==
: false" has extended folio_add_new_anon_rmap() to use on non-exclusive
: folios, already visible to others in swap cache and on LRU.
: 
: That renders its non-atomic __folio_set_swapbacked() unsafe: it risks
: overwriting concurrent atomic operations on folio->flags, losing bits
: added or restoring bits cleared.  Since it's only used in this risky way
: when folio_test_locked and !folio_test_anon, many such races are excluded;
: but, for example, isolations by folio_test_clear_lru() are vulnerable, and
: setting or clearing active.
: 
: It could just use the atomic folio_set_swapbacked(); but this function
: does try to avoid atomics where it can, so use a branch instead: just
: avoid setting swapbacked when it is already set, that is good enough. 
: (Swapbacked is normally stable once set: lazyfree can undo it, but only
: later, when found anon in a page table.)
: 
: This fixes a lot of instability under compaction and swapping loads:
: assorted "Bad page"s, VM_BUG_ON_FOLIO()s, apparently even page double
: frees - though I've not worked out what races could lead to the latter.

[akpm@linux-foundation.org: comment fixes, per David and akpm]
[v-songbaohua@oppo.com: lock the folio to avoid race]
  Link: https://lkml.kernel.org/r/20240622032002.53033-1-21cnbao@gmail.com
[hughd@google.com: folio_add_new_anon_rmap() careful __folio_set_swapbacked()]
  Link: https://lkml.kernel.org/r/f3599b1d-8323-0dc5-e9e0-fdb3cfc3dd5a@google.com
Link: https://lkml.kernel.org/r/20240617231137.80726-3-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Tested-by: Shuai Yuan <yuanshuai@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:18 -07:00
Barry Song
15bde4abab mm: extend rmap flags arguments for folio_add_new_anon_rmap
Patch series "mm: clarify folio_add_new_anon_rmap() and
__folio_add_anon_rmap()", v2.

This patchset is preparatory work for mTHP swapin.

folio_add_new_anon_rmap() assumes that new anon rmaps are always
exclusive.  However, this assumption doesn’t hold true for cases like
do_swap_page(), where a new anon might be added to the swapcache and is
not necessarily exclusive.

The patchset extends the rmap flags to allow folio_add_new_anon_rmap() to
handle both exclusive and non-exclusive new anon folios.  The
do_swap_page() function is updated to use this extended API with rmap
flags.  Consequently, all new anon folios now consistently use
folio_add_new_anon_rmap().  The special case for !folio_test_anon() in
__folio_add_anon_rmap() can be safely removed.

In conclusion, new anon folios always use folio_add_new_anon_rmap(),
regardless of exclusivity.  Old anon folios continue to use
__folio_add_anon_rmap() via folio_add_anon_rmap_pmd() and
folio_add_anon_rmap_ptes().


This patch (of 3):

In the case of a swap-in, a new anonymous folio is not necessarily
exclusive.  This patch updates the rmap flags to allow a new anonymous
folio to be treated as either exclusive or non-exclusive.  To maintain the
existing behavior, we always use EXCLUSIVE as the default setting.

[akpm@linux-foundation.org: cleanup and constifications per David and akpm]
[v-songbaohua@oppo.com: fix missing doc for flags of folio_add_new_anon_rmap()]
  Link: https://lkml.kernel.org/r/20240619210641.62542-1-21cnbao@gmail.com
[v-songbaohua@oppo.com: enhance doc for extend rmap flags arguments for folio_add_new_anon_rmap]
  Link: https://lkml.kernel.org/r/20240622030256.43775-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240617231137.80726-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240617231137.80726-2-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Tested-by: Shuai Yuan <yuanshuai@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:18 -07:00
Barry Song
20dfa5b7ad mm: set pte writable while pte_soft_dirty() is true in do_swap_page()
This patch leverages the new pte_needs_soft_dirty_wp() helper to optimize
a scenario where softdirty is enabled, but the softdirty flag has already
been set in do_swap_page().  In this situation, we can use pte_mkwrite
instead of applying write-protection since we don't depend on write
faults.

Link: https://lkml.kernel.org/r/20240607211358.4660-3-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:07 -07:00
Yosry Ahmed
b2d1f38b52 mm: swap: remove 'synchronous' argument to swap_read_folio()
Commit [1] introduced IO polling support duding swapin to reduce swap read
latency for block devices that can be polled.  However later commit [2]
removed polling support.  Commit [3] removed the remnants of polling
support from read_swap_cache_async() and __read_swap_cache_async(). 
However, it left behind some remnants in swap_read_folio(), the
'synchronous' argument.

swap_read_folio() reads the folio synchronously if synchronous=true or if
SWP_SYNCHRONOUS_IO is set in swap_info_struct.  The only caller that
passes synchronous=true is in do_swap_page() in the SWP_SYNCHRONOUS_IO
case.

Hence, the argument is redundant, it is only set to true when the swap
read would have been synchronous anyway. Remove it.

[1] Commit 23955622ff ("swap: add block io poll in swapin path")
[2] Commit 9650b453a3 ("block: ignore RWF_HIPRI hint for sync dio")
[3] Commit b243dcbf2f ("swap: remove remnants of polling from read_swap_cache_async")

Link: https://lkml.kernel.org/r/20240607045515.1836558-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:06 -07:00
Barry Song
c18160dba5 mm: swap: reuse exclusive folio directly instead of wp page faults
After swapping out, we perform a swap-in operation.  If we first read and
then write, we encounter a major fault in do_swap_page for reading, along
with additional minor faults in do_wp_page for writing.  However, the
latter appears to be unnecessary and inefficient.  Instead, we can
directly reuse in do_swap_page and completely eliminate the need for
do_wp_page.

This patch achieves that optimization specifically for exclusive folios. 
The following microbenchmark demonstrates the significant reduction in
minor faults.

 #define DATA_SIZE (2UL * 1024 * 1024)
 #define PAGE_SIZE (4UL * 1024)

 static void *read_write_data(char *addr)
 {
         char tmp;

         for (int i = 0; i < DATA_SIZE; i += PAGE_SIZE) {
                 tmp = *(volatile char *)(addr + i);
                 *(volatile char *)(addr + i) = tmp;
         }
 }

 int main(int argc, char **argv)
 {
         struct rusage ru;

         char *addr = mmap(NULL, DATA_SIZE, PROT_READ | PROT_WRITE,
                         MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
         memset(addr, 0x11, DATA_SIZE);

         do {
                 long old_ru_minflt, old_ru_majflt;
                 long new_ru_minflt, new_ru_majflt;

                 madvise(addr, DATA_SIZE, MADV_PAGEOUT);

                 getrusage(RUSAGE_SELF, &ru);
                 old_ru_minflt = ru.ru_minflt;
                 old_ru_majflt = ru.ru_majflt;

                 read_write_data(addr);
                 getrusage(RUSAGE_SELF, &ru);
                 new_ru_minflt = ru.ru_minflt;
                 new_ru_majflt = ru.ru_majflt;

                 printf("minor faults:%ld major faults:%ld\n",
                         new_ru_minflt - old_ru_minflt,
                         new_ru_majflt - old_ru_majflt);
         } while(0);

         return 0;
 }

w/o patch,
/ # ~/a.out
minor faults:512 major faults:512

w/ patch,
/ # ~/a.out
minor faults:0 major faults:512

Minor faults decrease to 0!

Link: https://lkml.kernel.org/r/20240602004502.26895-1-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:04 -07:00
Baolin Wang
43e027e414 mm: memory: extend finish_fault() to support large folio
Patch series "add mTHP support for anonymous shmem", v5.

Anonymous pages have already been supported for multi-size (mTHP)
allocation through commit 19eaf44954, that can allow THP to be
configured through the sysfs interface located at
'/sys/kernel/mm/transparent_hugepage/hugepage-XXkb/enabled'.

However, the anonymous shmem will ignore the anonymous mTHP rule
configured through the sysfs interface, and can only use the PMD-mapped
THP, that is not reasonable.  Many implement anonymous page sharing
through mmap(MAP_SHARED | MAP_ANONYMOUS), especially in database usage
scenarios, therefore, users expect to apply an unified mTHP strategy for
anonymous pages, also including the anonymous shared pages, in order to
enjoy the benefits of mTHP.  For example, lower latency than PMD-mapped
THP, smaller memory bloat than PMD-mapped THP, contiguous PTEs on ARM
architecture to reduce TLB miss etc.

As discussed in the bi-weekly MM meeting[1], the mTHP controls should
control all of shmem, not only anonymous shmem, but support will be added
iteratively.  Therefore, this patch set starts with support for anonymous
shmem.

The primary strategy is similar to supporting anonymous mTHP.  Introduce a
new interface '/mm/transparent_hugepage/hugepage-XXkb/shmem_enabled',
which can have almost the same values as the top-level
'/sys/kernel/mm/transparent_hugepage/shmem_enabled', with adding a new
additional "inherit" option and dropping the testing options 'force' and
'deny'.  By default all sizes will be set to "never" except PMD size,
which is set to "inherit".  This ensures backward compatibility with the
anonymous shmem enabled of the top level, meanwhile also allows
independent control of anonymous shmem enabled for each mTHP.

Use the page fault latency tool to measure the performance of 1G anonymous shmem
with 32 threads on my machine environment with: ARM64 Architecture, 32 cores,
125G memory:
base: mm-unstable
user-time    sys_time    faults_per_sec_per_cpu     faults_per_sec
0.04s        3.10s         83516.416                  2669684.890

mm-unstable + patchset, anon shmem mTHP disabled
user-time    sys_time    faults_per_sec_per_cpu     faults_per_sec
0.02s        3.14s         82936.359                  2630746.027

mm-unstable + patchset, anon shmem 64K mTHP enabled
user-time    sys_time    faults_per_sec_per_cpu     faults_per_sec
0.08s        0.31s         678630.231                 17082522.495

From the data above, it is observed that the patchset has a minimal impact
when mTHP is not enabled (some fluctuations observed during testing). 
When enabling 64K mTHP, there is a significant improvement of the page
fault latency.

[1] https://lore.kernel.org/all/f1783ff0-65bd-4b2b-8952-52b6822a0835@redhat.com/


This patch (of 6):

Add large folio mapping establishment support for finish_fault() as a
preparation, to support multi-size THP allocation of anonymous shmem pages
in the following patches.

Keep the same behavior (per-page fault) for non-anon shmem to avoid
inflating the RSS unintentionally, and we can discuss what size of mapping
to build when extending mTHP to control non-anon shmem in the future.

[baolin.wang@linux.alibaba.com: avoid going beyond the PMD pagetable size]
  Link: https://lkml.kernel.org/r/b0e6a8b1-a32c-459e-ae67-fde5d28773e6@linux.alibaba.com
[baolin.wang@linux.alibaba.com: use 'PTRS_PER_PTE' instead of 'PTRS_PER_PTE - 1']
  Link: https://lkml.kernel.org/r/e1f5767a-2c9b-4e37-afe6-1de26fe54e41@linux.alibaba.com
Link: https://lkml.kernel.org/r/cover.1718090413.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/3a190892355989d42f59cf9f2f98b94694b0d24d.1718090413.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:03 -07:00
Chuanhua Han
508758960b mm: swap: entirely map large folios found in swapcache
When a large folio is found in the swapcache, the current implementation
requires calling do_swap_page() nr_pages times, resulting in nr_pages page
faults.  This patch opts to map the entire large folio at once to minimize
page faults.  Additionally, redundant checks and early exits for ARM64 MTE
restoring are removed.

Link: https://lkml.kernel.org/r/20240529082824.150954-7-21cnbao@gmail.com
Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
Co-developed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:01 -07:00
Chuanhua Han
4c3f966436 mm: swap: make should_try_to_free_swap() support large-folio
The function should_try_to_free_swap() operates under the assumption that
swap-in always occurs at the normal page granularity, i.e.,
folio_nr_pages() = 1.  However, in reality, for large folios,
add_to_swap_cache() will invoke folio_ref_add(folio, nr).  To accommodate
large folio swap-in, this patch eliminates this assumption.

Link: https://lkml.kernel.org/r/20240529082824.150954-6-21cnbao@gmail.com
Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
Co-developed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: Chris Li <chrisl@kernel.org>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:01 -07:00
Barry Song
29f252cdc2 mm: introduce arch_do_swap_page_nr() which allows restore metadata for nr pages
Should do_swap_page() have the capability to directly map a large folio,
metadata restoration becomes necessary for a specified number of pages
denoted as nr.  It's important to highlight that metadata restoration is
solely required by the SPARC platform, which, however, does not enable
THP_SWAP.  Consequently, in the present kernel configuration, there exists
no practical scenario where users necessitate the restoration of nr
metadata.  Platforms implementing THP_SWAP might invoke this function with
nr values exceeding 1, subsequent to do_swap_page() successfully mapping
an entire large folio.  Nonetheless, their arch_do_swap_page_nr()
functions remain empty.

Link: https://lkml.kernel.org/r/20240529082824.150954-5-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gao Xiang <xiang@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:01 -07:00
Mateusz Guzik
3577dbb192 mm: batch unlink_file_vma calls in free_pgd_range
Execs of dynamically linked binaries at 20-ish cores are bottlenecked on
the i_mmap_rwsem semaphore, while the biggest singular contributor is
free_pgd_range inducing the lock acquire back-to-back for all consecutive
mappings of a given file.

Tracing the count of said acquires while building the kernel shows:
[1, 2)     799579 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[2, 3)          0 |                                                    |
[3, 4)       3009 |                                                    |
[4, 5)       3009 |                                                    |
[5, 6)     326442 |@@@@@@@@@@@@@@@@@@@@@                               |

So in particular there were 326442 opportunities to coalesce 5 acquires
into 1.

Doing so increases execs per second by 4% (~50k to ~52k) when running
the benchmark linked below.

The lock remains the main bottleneck, I have not looked at other spots
yet.

Bench can be found here:
http://apollo.backplane.com/DFlyMisc/doexec.c

$ cc -O2 -o shared-doexec doexec.c
$ ./shared-doexec $(nproc)

Note this particular test makes sure binaries are separate, but the
loader is shared.

Stats collected on the patched kernel (+ "noinline") with:
bpftrace -e 'kprobe:unlink_file_vma_batch_process
{ @ = lhist(((struct unlink_vma_file_batch *)arg0)->count, 0, 8, 1); }'

Link: https://lkml.kernel.org/r/20240521234321.359501-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:58 -07:00
Bang Li
6faa49d1c4 mm: use update_mmu_tlb_range() to simplify code
Let us simplify the code by update_mmu_tlb_range().

Link: https://lkml.kernel.org/r/20240522061204.117421-4-libang.li@antgroup.com
Signed-off-by: Bang Li <libang.li@antgroup.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:57 -07:00
David Hildenbrand
fce831c920 mm/memory: cleanly support zeropage in vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()
For now we only get the (small) zeropage mapped to user space in four
cases (excluding VM_PFNMAP mappings, such as /proc/vmstat):

(1) Read page faults in anonymous VMAs (MAP_PRIVATE|MAP_ANON):
    do_anonymous_page() will not refcount it and map it pte_mkspecial()
(2) UFFDIO_ZEROPAGE on anonymous VMA or COW mapping of shmem
    (MAP_PRIVATE). mfill_atomic_pte_zeropage() will not refcount it and
    map it pte_mkspecial().
(3) KSM in mergeable VMA (anonymous VMA or COW mapping).
    cmp_and_merge_page() will not refcount it and map it
    pte_mkspecial().
(4) FSDAX as an optimization for holes.
    vmf_insert_mixed()->__vm_insert_mixed() might end up calling
    insert_page() without CONFIG_ARCH_HAS_PTE_SPECIAL, refcounting the
    zeropage and not mapping it pte_mkspecial(). With
    CONFIG_ARCH_HAS_PTE_SPECIAL, we'll call insert_pfn() where we will
    not refcount it and map it pte_mkspecial().

In case (4), we might not have VM_MIXEDMAP set: while fs/fuse/dax.c sets
VM_MIXEDMAP, we removed it for ext4 fsdax in commit e1fb4a0864 ("dax:
remove VM_MIXEDMAP for fsdax and device dax") and for XFS in commit
e1fb4a0864 ("dax: remove VM_MIXEDMAP for fsdax and device dax").

Without CONFIG_ARCH_HAS_PTE_SPECIAL and with VM_MIXEDMAP, vm_normal_page()
would currently return the zeropage.  We'll refcount the zeropage when
mapping and when unmapping.

Without CONFIG_ARCH_HAS_PTE_SPECIAL and without VM_MIXEDMAP,
vm_normal_page() would currently refuse to return the zeropage.  So we'd
refcount it when mapping but not when unmapping it ...  do we have fsdax
without CONFIG_ARCH_HAS_PTE_SPECIAL in practice?  Hard to tell.

Independent of that, we should never refcount the zeropage when we might
be holding that reference for a long time, because even without an
accounting imbalance we might overflow the refcount.  As there is interest
in using the zeropage also in other VM_MIXEDMAP mappings, let's add clean
support for that in the cases where it makes sense:

(A) Never refcount the zeropage when mapping it:

In insert_page(), special-case the zeropage, do not refcount it, and use
pte_mkspecial().  Don't involve insert_pfn(), adjusting insert_page()
looks cleaner than branching off to insert_pfn().

(B) Never refcount the zeropage when unmapping it:

In vm_normal_page(), also don't return the zeropage in a VM_MIXEDMAP
mapping without CONFIG_ARCH_HAS_PTE_SPECIAL.  Add a VM_WARN_ON_ONCE()
sanity check if we'd ever return the zeropage, which could happen if
someone forgets to set pte_mkspecial() when mapping the zeropage. 
Document that.

(C) Allow the zeropage only where reasonable

s390x never wants the zeropage in some processes running legacy KVM guests
that make use of storage keys.  So disallow that.

Further, using the zeropage in COW mappings is unproblematic (just what we
do for other COW mappings), because FAULT_FLAG_UNSHARE can just unshare it
and GUP with FOLL_LONGTERM would work as expected.

Similarly, mappings that can never have writable PTEs (implying no write
faults) are also not problematic, because nothing could end up mapping the
PTE writable by mistake later.  But in case we could have writable PTEs,
we'll only allow the zeropage in FSDAX VMAs, that are incompatible with
GUP and are blocked there completely.

We'll always require the zeropage to be mapped with pte_special(). 
GUP-fast will reject the zeropage that way, but GUP-slow will allow it. 
(Note that GUP does not refcount the zeropage with FOLL_PIN, because there
were issues with overflowing the refcount in the past).

Add sanity checks to can_change_pte_writable() and wp_page_reuse(), to
catch early during testing if we'd ever find a zeropage unexpectedly in
code that wants to upgrade write permissions.

Convert the BUG_ON in vm_mixed_ok() to an ordinary check and simply fail
with VM_FAULT_SIGBUS, like we do for other sanity checks.  Drop the stale
comment regarding reserved pages from insert_page().

Note that:
* we won't mess with VM_PFNMAP mappings for now. remap_pfn_range() and
  vmf_insert_pfn() would allow the zeropage in some cases and
  not refcount it.
* vmf_insert_pfn*() will reject the zeropage in VM_MIXEDMAP
  mappings and we'll leave that alone for now. People can simply use
  one of the other interfaces.
* we won't bother with the huge zeropage for now. It's never
  PTE-mapped and also GUP does not special-case it yet.

Link: https://lkml.kernel.org/r/20240522125713.775114-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:56 -07:00
David Hildenbrand
11b914ee9e mm/memory: move page_count() check into validate_page_before_insert()
Patch series "mm/memory: cleanly support zeropage in vm_insert_page*(),
vm_map_pages*() and vmf_insert_mixed()", v2.

There is interest in mapping zeropages via vm_insert_pages() [1] into
MAP_SHARED mappings.

For now, we only get zeropages in MAP_SHARED mappings via
vmf_insert_mixed() from FSDAX code, and I think it's a bit shaky in some
cases because we refcount the zeropage when mapping it but not necessarily
always when unmapping it ...  and we should actually never refcount it.

It's all a bit tricky, especially how zeropages in MAP_SHARED mappings
interact with GUP (FOLL_LONGTERM), mprotect(), write-faults and s390x
forbidding the shared zeropage (rewrite [2] s now upstream).

This series tries to take the careful approach of only allowing the
zeropage where it is likely safe to use (which should cover the existing
FSDAX use case and [1]), preventing that it could accidentally get mapped
writable during a write fault, mprotect() etc, and preventing issues with
FOLL_LONGTERM in the future with other users.

Tested with a patch from Vincent that uses the zeropage in context of
[1].

[1] https://lkml.kernel.org/r/20240430111354.637356-1-vdonnefort@google.com
[2] https://lkml.kernel.org/r/20240411161441.910170-1-david@redhat.com


This patch (of 3):

We'll now also cover the case where insert_page() is called from
__vm_insert_mixed(), which sounds like the right thing to do.

Link: https://lkml.kernel.org/r/20240522125713.775114-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:56 -07:00
Illia Ostapyshyn
0ba5e806e1 mm/vmscan: update stale references to shrink_page_list
Commit 49fd9b6df5 ("mm/vmscan: fix a lot of comments") renamed
shrink_page_list() to shrink_folio_list().  Fix up the remaining
references to the old name in comments and documentation.

Link: https://lkml.kernel.org/r/20240517091348.1185566-1-illia@yshyn.com
Signed-off-by: Illia Ostapyshyn <illia@yshyn.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:52 -07:00
Andrew Bresticker
ab1ffc86cb mm/memory: don't require head page for do_set_pmd()
The requirement that the head page be passed to do_set_pmd() was added in
commit ef37b2ea08 ("mm/memory: page_add_file_rmap() ->
folio_add_file_rmap_[pte|pmd]()") and prevents pmd-mapping in the
finish_fault() and filemap_map_pages() paths if the page to be inserted is
anything but the head page for an otherwise suitable vma and pmd-sized
page.

Matthew said:

: We're going to stop using PMDs to map large folios unless the fault is
: within the first 4KiB of the PMD.  No idea how many workloads that
: affects, but it only needs to be backported as far as v6.8, so we may
: as well backport it.

Link: https://lkml.kernel.org/r/20240611153216.2794513-1-abrestic@rivosinc.com
Fixes: ef37b2ea08 ("mm/memory: page_add_file_rmap() -> folio_add_file_rmap_[pte|pmd]()")
Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:11 -07:00
Kefeng Wang
cfdd12b482 mm: fix possible OOB in numa_rebuild_large_mapping()
The large folio is mapped with folio size(not greater PMD_SIZE) aligned
virtual address during the pagefault, ie, 'addr = ALIGN_DOWN(vmf->address,
nr_pages * PAGE_SIZE)' in do_anonymous_page().  But after the mremap(),
the virtual address only requires PAGE_SIZE alignment.  Also pte is moved
to new in move_page_tables(), then traversal of the new pte in the
numa_rebuild_large_mapping() could hit the following issue,

   Unable to handle kernel paging request at virtual address 00000a80c021a788
   Mem abort info:
     ESR = 0x0000000096000004
     EC = 0x25: DABT (current EL), IL = 32 bits
     SET = 0, FnV = 0
     EA = 0, S1PTW = 0
     FSC = 0x04: level 0 translation fault
   Data abort info:
     ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
     CM = 0, WnR = 0, TnD = 0, TagAccess = 0
     GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
   user pgtable: 4k pages, 48-bit VAs, pgdp=00002040341a6000
   [00000a80c021a788] pgd=0000000000000000, p4d=0000000000000000
   Internal error: Oops: 0000000096000004 [#1] SMP
   ...
   CPU: 76 PID: 15187 Comm: git Kdump: loaded Tainted: G        W          6.10.0-rc2+ #209
   Hardware name: Huawei TaiShan 2280 V2/BC82AMDD, BIOS 1.79 08/21/2021
   pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
   pc : numa_rebuild_large_mapping+0x338/0x638
   lr : numa_rebuild_large_mapping+0x320/0x638
   sp : ffff8000b41c3b00
   x29: ffff8000b41c3b30 x28: ffff8000812a0000 x27: 00000000000a8000
   x26: 00000000000000a8 x25: 0010000000000001 x24: ffff20401c7170f0
   x23: 0000ffff33a1e000 x22: 0000ffff33a76000 x21: ffff20400869eca0
   x20: 0000ffff33976000 x19: 00000000000000a8 x18: ffffffffffffffff
   x17: 0000000000000000 x16: 0000000000000020 x15: ffff8000b41c36a8
   x14: 0000000000000000 x13: 205d373831353154 x12: 5b5d333331363732
   x11: 000000000011ff78 x10: 000000000011ff10 x9 : ffff800080273f30
   x8 : 000000320400869e x7 : c0000000ffffd87f x6 : 00000000001e6ba8
   x5 : ffff206f3fb5af88 x4 : 0000000000000000 x3 : 0000000000000000
   x2 : 0000000000000000 x1 : fffffdffc0000000 x0 : 00000a80c021a780
   Call trace:
    numa_rebuild_large_mapping+0x338/0x638
    do_numa_page+0x3e4/0x4e0
    handle_pte_fault+0x1bc/0x238
    __handle_mm_fault+0x20c/0x400
    handle_mm_fault+0xa8/0x288
    do_page_fault+0x124/0x498
    do_translation_fault+0x54/0x80
    do_mem_abort+0x4c/0xa8
    el0_da+0x40/0x110
    el0t_64_sync_handler+0xe4/0x158
    el0t_64_sync+0x188/0x190

Fix it by making the start and end not only within the vma range, but also
within the page table range.

Link: https://lkml.kernel.org/r/20240612122822.4033433-1-wangkefeng.wang@huawei.com
Fixes: d2136d749d ("mm: support multi-size THP numa balancing")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-15 10:43:07 -07:00
David Hildenbrand
384a746bb5 Revert "mm: init_mlocked_on_free_v3"
There was insufficient review and no agreement that this is the right
approach.

There are serious flaws with the implementation that make processes using
mlock() not even work with simple fork() [1] and we get reliable crashes
when rebooting.

Further, simply because we might be unmapping a single PTE of a large
mlocked folio, we shouldn't zero out the whole folio.

... especially because the code can also *corrupt* urelated memory because
	kernel_init_pages(page, folio_nr_pages(folio));

Could end up writing outside of the actual folio if we work with a tail
page.

Let's revert it.  Once there is agreement that this is the right approach,
the issues were fixed and there was reasonable review and proper testing,
we can consider it again.

[1] https://lkml.kernel.org/r/4da9da2f-73e4-45fd-b62f-a8a513314057@redhat.com

Link: https://lkml.kernel.org/r/20240605091710.38961-1-david@redhat.com
Fixes: ba42b524a0 ("mm: init_mlocked_on_free_v3")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: David Wang <00107082@163.com>
Closes: https://lore.kernel.org/lkml/20240528151340.4282-1-00107082@163.com/
Reported-by: Lance Yang <ioworker0@gmail.com>
Closes: https://lkml.kernel.org/r/20240601140917.43562-1-ioworker0@gmail.com
Acked-by: Lance Yang <ioworker0@gmail.com>
Cc: York Jasper Niebuhr <yjnworkstation@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-15 10:43:05 -07:00