linux-stable.git/include/linux/mm_types.h, branch v5.18.3

Merge tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache

2022-03-23T00:03:12+00:00

Pull folio updates from Matthew Wilcox:

 - Rewrite how munlock works to massively reduce the contention on
   i_mmap_rwsem (Hugh Dickins):

     https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/

 - Sort out the page refcount mess for ZONE_DEVICE pages (Christoph
   Hellwig):

     https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/

 - Convert GUP to use folios and make pincount available for order-1
   pages. (Matthew Wilcox)

 - Convert a few more truncation functions to use folios (Matthew
   Wilcox)

 - Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew
   Wilcox)

 - Convert rmap_walk to use folios (Matthew Wilcox)

 - Convert most of shrink_page_list() to use a folio (Matthew Wilcox)

 - Add support for creating large folios in readahead (Matthew Wilcox)

* tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits)
  mm/damon: minor cleanup for damon_pa_young
  selftests/vm/transhuge-stress: Support file-backed PMD folios
  mm/filemap: Support VM_HUGEPAGE for file mappings
  mm/readahead: Switch to page_cache_ra_order
  mm/readahead: Align file mappings for non-DAX
  mm/readahead: Add large folio readahead
  mm: Support arbitrary THP sizes
  mm: Make large folios depend on THP
  mm: Fix READ_ONLY_THP warning
  mm/filemap: Allow large folios to be added to the page cache
  mm: Turn can_split_huge_page() into can_split_folio()
  mm/vmscan: Convert pageout() to take a folio
  mm/vmscan: Turn page_check_references() into folio_check_references()
  mm/vmscan: Account large folios correctly
  mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios
  mm/vmscan: Free non-shmem folios without splitting them
  mm/rmap: Constify the rmap_walk_control argument
  mm/rmap: Convert rmap_walk() to take a folio
  mm: Turn page_anon_vma() into folio_anon_vma()
  mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read()
  ...

Merge tag 'x86-pasid-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-03-21T19:28:13+00:00

Pull x86 PASID support from Thomas Gleixner:
 "Reenable ENQCMD/PASID support:

   - Simplify the PASID handling to allocate the PASID once, associate
     it to the mm of a process and free it on mm_exit().

     The previous attempt of refcounted PASIDs and dynamic
     alloc()/free() turned out to be error prone and too complex. The
     PASID space is 20bits, so the case of resource exhaustion is a pure
     academic concern.

   - Populate the PASID MSR on demand via #GP to avoid racy updates via
     IPIs.

   - Reenable ENQCMD and let objtool check for the forbidden usage of
     ENQCMD in the kernel.

   - Update the documentation for Shared Virtual Addressing accordingly"

* tag 'x86-pasid-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation/x86: Update documentation for SVA (Shared Virtual Addressing)
  tools/objtool: Check for use of the ENQCMD instruction in the kernel
  x86/cpufeatures: Re-enable ENQCMD
  x86/traps: Demand-populate PASID MSR via #GP
  sched: Define and initialize a flag to identify valid PASID in the task
  x86/fpu: Clear PASID when copying fpstate
  iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit
  kernel/fork: Initialize mm's PASID
  iommu/ioasid: Introduce a helper to check for valid PASIDs
  mm: Change CONFIG option for mm->pasid field
  iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVA

mm: Make compound_pincount always available

2022-03-21T16:56:35+00:00

Move compound_pincount from the third page to the second page, which
means it's available for all compound pages.  That lets us delete
hpage_pincount_available().

On 32-bit systems, there isn't enough space for both compound_pincount
and compound_nr in the second page (it would collide with page->private,
which is in use for pages in the swap cache), so revert the optimisation
of storing both compound_order and compound_nr on 32-bit systems.

Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: John Hubbard 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: William Kucharski

mm: refactor vm_area_struct::anon_vma_name usage code

2022-03-05T19:08:32+00:00

Avoid mixing strings and their anon_vma_name referenced pointers by
using struct anon_vma_name whenever possible.  This simplifies the code
and allows easier sharing of anon_vma_name structures when they
represent the same name.

[surenb@google.com: fix comment]

Link: https://lkml.kernel.org/r/20220223153613.835563-1-surenb@google.com
Link: https://lkml.kernel.org/r/20220224231834.1481408-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan 
Suggested-by: Matthew Wilcox 
Suggested-by: Michal Hocko 
Acked-by: Michal Hocko 
Cc: Colin Cross 
Cc: Sumit Semwal 
Cc: Dave Hansen 
Cc: Kees Cook 
Cc: "Kirill A. Shutemov" 
Cc: Vlastimil Babka 
Cc: Johannes Weiner 
Cc: "Eric W. Biederman" 
Cc: Christian Brauner 
Cc: Alexey Gladkov 
Cc: Sasha Levin 
Cc: Chris Hyser 
Cc: Davidlohr Bueso 
Cc: Peter Collingbourne 
Cc: Xiaofeng Cao 
Cc: David Hildenbrand 
Cc: Cyrill Gorcunov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/munlock: maintain page->mlock_count while unevictable

2022-02-17T16:56:57+00:00

Previous patches have been preparatory: now implement page->mlock_count.
The ordering of the "Unevictable LRU" is of no significance, and there is
no point holding unevictable pages on a list: place page->mlock_count to
overlay page->lru.prev (since page->lru.next is overlaid by compound_head,
which needs to be even so as not to satisfy PageTail - though 2 could be
added instead of 1 for each mlock, if that's ever an improvement).

But it's only safe to rely on or modify page->mlock_count while lruvec
lock is held and page is on unevictable "LRU" - we can save lots of edits
by continuing to pretend that there's an imaginary LRU here (there is an
unevictable count which still needs to be maintained, but not a list).

The mlock_count technique suffers from an unreliability much like with
page_mlock(): while someone else has the page off LRU, not much can
be done.  As before, err on the safe side (behave as if mlock_count 0),
and let try_to_unlock_one() move the page to unevictable if reclaim finds
out later on - a few misplaced pages don't matter, what we want to avoid
is imbalancing reclaim by flooding evictable lists with unevictable pages.

I am not a fan of "if (!isolate_lru_page(page)) putback_lru_page(page);":
if we have taken lruvec lock to get the page off its present list, then
we save everyone trouble (and however many extra atomic ops) by putting
it on its destination list immediately.

Signed-off-by: Hugh Dickins 
Acked-by: Vlastimil Babka 
Signed-off-by: Matthew Wilcox (Oracle)

mm: Change CONFIG option for mm->pasid field

2022-02-14T18:23:50+00:00

This currently depends on CONFIG_IOMMU_SUPPORT. But it is only
needed when CONFIG_IOMMU_SVA option is enabled.

Change the CONFIG guards around definition and initialization
of mm->pasid field.

Suggested-by: Jacob Pan 
Signed-off-by: Fenghua Yu 
Signed-off-by: Borislav Petkov 
Reviewed-by: Tony Luck 
Reviewed-by: Thomas Gleixner 
Reviewed-by: Lu Baolu 
Link: https://lore.kernel.org/r/20220207230254.3342514-3-fenghua.yu@intel.com

mm: page->mapping folio->mapping should have the same offset

2022-01-30T07:56:58+00:00

As with the other members of folio, the offset of page->mapping and
folio->mapping must be the same.  The compile-time check was
inadvertently removed during development.  Add it back.

[willy@infradead.org: changelog redo]

Link: https://lkml.kernel.org/r/20220104011734.21714-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang 
Reviewed-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'slab-for-5.17-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

2022-01-18T04:40:47+00:00

Pull more slab updates from Vlastimil Babka:
 "Finish the conversion to struct slab by removing slab-specific fields
  from struct page.

  The first slab update (see merge commit ca1a46d6f506) did most of the
  conversion, but there was also series in iommu tree removing the
  iommu's usage of struct page 'freelist' field, blocking the final
  struct page cleanup.

  Now that the iommu changes have been merged, we can finish the job"

* tag 'slab-for-5.17-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  mm: Remove slab from struct page

Merge branch 'akpm' (patches from Andrew)

2022-01-15T18:37:06+00:00

Merge misc updates from Andrew Morton:
 "146 patches.

  Subsystems affected by this patch series: kthread, ia64, scripts,
  ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
  dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
  memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
  userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
  ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
  damon)"

* emailed patches from Andrew Morton : (146 commits)
  mm/damon: hide kernel pointer from tracepoint event
  mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
  mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
  mm/damon/dbgfs: remove an unnecessary variable
  mm/damon: move the implementation of damon_insert_region to damon.h
  mm/damon: add access checking for hugetlb pages
  Docs/admin-guide/mm/damon/usage: update for schemes statistics
  mm/damon/dbgfs: support all DAMOS stats
  Docs/admin-guide/mm/damon/reclaim: document statistics parameters
  mm/damon/reclaim: provide reclamation statistics
  mm/damon/schemes: account how many times quota limit has exceeded
  mm/damon/schemes: account scheme actions that successfully applied
  mm/damon: remove a mistakenly added comment for a future feature
  Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
  Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
  Docs/admin-guide/mm/damon/usage: remove redundant information
  Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
  mm/damon: convert macro functions to static inline functions
  mm/damon: modify damon_rand() macro to static inline function
  mm/damon: move damon_rand() definition into damon.h
  ...

mm/rmap: fix potential batched TLB flush race

2022-01-15T14:30:31+00:00

In theory, the following race is possible for batched TLB flushing.

  CPU0                               CPU1
  ----                               ----
  shrink_page_list()
                                     unmap
                                       zap_pte_range()
                                         flush_tlb_batched_pending()
                                           flush_tlb_mm()
    try_to_unmap()
      set_tlb_ubc_flush_pending()
        mm->tlb_flush_batched = true
                                           mm->tlb_flush_batched = false

After the TLB is flushed on CPU1 via flush_tlb_mm() and before
mm->tlb_flush_batched is set to false, some PTE is unmapped on CPU0 and
the TLB flushing is pended.  Then the pended TLB flushing will be lost.
Although both set_tlb_ubc_flush_pending() and
flush_tlb_batched_pending() are called with PTL locked, different PTL
instances may be used.

Because the race window is really small, and the lost TLB flushing will
cause problem only if a TLB entry is inserted before the unmapping in
the race window, the race is only theoretical.  But the fix is simple
and cheap too.

Syzbot has reported this too as follows:

    ==================================================================
    BUG: KCSAN: data-race in flush_tlb_batched_pending / try_to_unmap_one

    write to 0xffff8881072cfbbc of 1 bytes by task 17406 on cpu 1:
     flush_tlb_batched_pending+0x5f/0x80 mm/rmap.c:691
     madvise_free_pte_range+0xee/0x7d0 mm/madvise.c:594
     walk_pmd_range mm/pagewalk.c:128 [inline]
     walk_pud_range mm/pagewalk.c:205 [inline]
     walk_p4d_range mm/pagewalk.c:240 [inline]
     walk_pgd_range mm/pagewalk.c:277 [inline]
     __walk_page_range+0x981/0x1160 mm/pagewalk.c:379
     walk_page_range+0x131/0x300 mm/pagewalk.c:475
     madvise_free_single_vma mm/madvise.c:734 [inline]
     madvise_dontneed_free mm/madvise.c:822 [inline]
     madvise_vma mm/madvise.c:996 [inline]
     do_madvise+0xe4a/0x1140 mm/madvise.c:1202
     __do_sys_madvise mm/madvise.c:1228 [inline]
     __se_sys_madvise mm/madvise.c:1226 [inline]
     __x64_sys_madvise+0x5d/0x70 mm/madvise.c:1226
     do_syscall_x64 arch/x86/entry/common.c:50 [inline]
     do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
     entry_SYSCALL_64_after_hwframe+0x44/0xae

    write to 0xffff8881072cfbbc of 1 bytes by task 71 on cpu 0:
     set_tlb_ubc_flush_pending mm/rmap.c:636 [inline]
     try_to_unmap_one+0x60e/0x1220 mm/rmap.c:1515
     rmap_walk_anon+0x2fb/0x470 mm/rmap.c:2301
     try_to_unmap+0xec/0x110
     shrink_page_list+0xe91/0x2620 mm/vmscan.c:1719
     shrink_inactive_list+0x3fb/0x730 mm/vmscan.c:2394
     shrink_list mm/vmscan.c:2621 [inline]
     shrink_lruvec+0x3c9/0x710 mm/vmscan.c:2940
     shrink_node_memcgs+0x23e/0x410 mm/vmscan.c:3129
     shrink_node+0x8f6/0x1190 mm/vmscan.c:3252
     kswapd_shrink_node mm/vmscan.c:4022 [inline]
     balance_pgdat+0x702/0xd30 mm/vmscan.c:4213
     kswapd+0x200/0x340 mm/vmscan.c:4473
     kthread+0x2c7/0x2e0 kernel/kthread.c:327
     ret_from_fork+0x1f/0x30

    value changed: 0x01 -> 0x00

    Reported by Kernel Concurrency Sanitizer on:
    CPU: 0 PID: 71 Comm: kswapd0 Not tainted 5.16.0-rc1-syzkaller #0
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
    ==================================================================

[akpm@linux-foundation.org: tweak comments]

Link: https://lkml.kernel.org/r/20211201021104.126469-1-ying.huang@intel.com
Signed-off-by: "Huang, Ying" 
Reported-by: syzbot+aa5bebed695edaccf0df@syzkaller.appspotmail.com
Cc: Nadav Amit 
Cc: Mel Gorman 
Cc: Andrea Arcangeli 
Cc: Andy Lutomirski 
Cc: Dave Hansen 
Cc: Will Deacon 
Cc: Yu Zhao 
Cc: Marco Elver 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds