linux-stable.git/mm/compaction.c, branch v6.3.3

Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-02-24T01:09:35+00:00

Pull MM updates from Andrew Morton:

 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
   F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X
   bit.

 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.

 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes

 - Johannes Weiner has a series ("mm: push down lock_page_memcg()")
   which does perform some memcg maintenance and cleanup work.

 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".

   These filters provide users with finer-grained control over DAMOS's
   actions. SeongJae has also done some DAMON cleanup work.

 - Kairui Song adds a series ("Clean up and fixes for swap").

 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".

 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.

 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".

 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".

 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".

 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".

 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series
   "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
   swap PTEs".

 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".

 - Sergey Senozhatsky has improved zsmalloc's memory utilization with
   his series "zsmalloc: make zspage chain size configurable".

 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.

   The previous BPF-based approach had shortcomings. See "mm: In-kernel
   support for memory-deny-write-execute (MDWE)".

 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".

 - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".

 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a
   per-node basis. See the series "Introduce per NUMA node memory error
   statistics".

 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage
   during compaction".

 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".

 - Christoph Hellwig has removed block_device_operations.rw_page() in
   ths series "remove ->rw_page".

 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".

 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier
   functions".

 - Some pagemap cleanup and generalization work in Mike Rapoport's
   series "mm, arch: add generic implementation of pfn_valid() for
   FLATMEM" and "fixups for generic implementation of pfn_valid()"

 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".

 - Jason Gunthorpe rationalized the GUP system's interface to the rest
   of the kernel in the series "Simplify the external interface for
   GUP".

 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface. To support this, we'll temporarily be
   printing warnings when people use the debugfs interface. See the
   series "mm/damon: deprecate DAMON debugfs interface".

 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.

 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".

 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".

* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
  include/linux/migrate.h: remove unneeded externs
  mm/memory_hotplug: cleanup return value handing in do_migrate_range()
  mm/uffd: fix comment in handling pte markers
  mm: change to return bool for isolate_movable_page()
  mm: hugetlb: change to return bool for isolate_hugetlb()
  mm: change to return bool for isolate_lru_page()
  mm: change to return bool for folio_isolate_lru()
  objtool: add UACCESS exceptions for __tsan_volatile_read/write
  kmsan: disable ftrace in kmsan core code
  kasan: mark addr_has_metadata __always_inline
  mm: memcontrol: rename memcg_kmem_enabled()
  sh: initialize max_mapnr
  m68k/nommu: add missing definition of ARCH_PFN_OFFSET
  mm: percpu: fix incorrect size in pcpu_obj_full_size()
  maple_tree: reduce stack usage with gcc-9 and earlier
  mm: page_alloc: call panic() when memoryless node allocation fails
  mm: multi-gen LRU: avoid futile retries
  migrate_pages: move THP/hugetlb migration support check to simplify code
  migrate_pages: batch flushing TLB
  migrate_pages: share more code between _unmap and _move
  ...

mm: change to return bool for isolate_movable_page()

2023-02-20T20:46:17+00:00

Now the isolate_movable_page() can only return 0 or -EBUSY, and no users
will care about the negative return value, thus we can convert the
isolate_movable_page() to return a boolean value to make the code more
clear when checking the movable page isolation state.

No functional changes intended.

[akpm@linux-foundation.org: remove unneeded comment, per Matthew]
Link: https://lkml.kernel.org/r/cb877f73f4fff8d309611082ec740a7065b1ade0.1676424378.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang 
Acked-by: David Hildenbrand 
Reviewed-by: Matthew Wilcox (Oracle) 
Acked-by: Linus Torvalds 
Reviewed-by: SeongJae Park 
Signed-off-by: Andrew Morton

mm, compaction: finish pageblocks on complete migration failure

2023-02-03T06:33:30+00:00

Commit 7efc3b726103 ("mm/compaction: fix set skip in
fast_find_migrateblock") address an issue where a pageblock selected by
fast_find_migrateblock() was ignored.  Unfortunately, the same fix
resulted in numerous reports of khugepaged or kcompactd stalling for long
periods of time or consuming 100% of CPU.

Tracing showed that there was a lot of rescanning between a small subset
of pageblocks because the conditions for marking the block skip are not
met.  The scan is not reaching the end of the pageblock because enough
pages were isolated but none were migrated successfully.  Eventually it
circles back to the same block.

Pageblock skip tracking tries to minimise both latency and excessive
scanning but tracking exactly when a block is fully scanned requires an
excessive amount of state.  This patch forcibly rescans a pageblock when
all isolated pages fail to migrate even though it could be for transient
reasons such as page writeback or page dirty.  This will sometimes migrate
too many pages but pageblocks will be marked skip and forward progress
will be made.

"Usemen" from the mmtests configuration
workload-usemem-stress-numa-compact was used to stress compaction.  The
compaction trace events were recorded using a 6.2-rc5 kernel that includes
commit 7efc3b726103 and count of unique ranges were measured.  The top 5
ranges were

   3076 range=(0x10ca00-0x10cc00)
   3076 range=(0x110a00-0x110c00)
   3098 range=(0x13b600-0x13b800)
   3104 range=(0x141c00-0x141e00)
  11424 range=(0x11b600-0x11b800)

While this workload is very different than what the bugs reported, the
pattern of the same subset of blocks being repeatedly scanned is observed.
At one point, *only* the range range=(0x11b600 ~ 0x11b800) was scanned
for 2 seconds.  14 seconds passed between the first migration-related
event and the last.

With the series applied including this patch, the top 5 ranges were

      1 range=(0x11607e-0x116200)
      1 range=(0x116200-0x116278)
      1 range=(0x116278-0x116400)
      1 range=(0x116400-0x116424)
      1 range=(0x116424-0x116600)

Only unique ranges were scanned and the time between the first
migration-related event was 0.11 milliseconds.

Link: https://lkml.kernel.org/r/20230125134434.18017-5-mgorman@techsingularity.net
Fixes: 7efc3b726103 ("mm/compaction: fix set skip in fast_find_migrateblock")
Signed-off-by: Mel Gorman 
Cc: Chuyi Zhou 
Cc: Jiri Slaby 
Cc: Maxim Levitsky 
Cc: Michal Hocko 
Cc: Paolo Bonzini 
Cc: Pedro Falcato 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm, compaction: finish scanning the current pageblock if requested

2023-02-03T06:33:30+00:00

cc->finish_pageblock is set when the current pageblock should be rescanned
but fast_find_migrateblock can select an alternative block.  Disable
fast_find_migrateblock when the current pageblock scan should be
completed.

Link: https://lkml.kernel.org/r/20230125134434.18017-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman 
Cc: Chuyi Zhou 
Cc: Jiri Slaby 
Cc: Maxim Levitsky 
Cc: Michal Hocko 
Cc: Paolo Bonzini 
Cc: Pedro Falcato 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm, compaction: check if a page has been captured before draining PCP pages

2023-02-03T06:33:30+00:00

If a page has been captured then draining is unnecssary so check first for
a captured page.

Link: https://lkml.kernel.org/r/20230125134434.18017-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman 
Cc: Chuyi Zhou 
Cc: Jiri Slaby 
Cc: Maxim Levitsky 
Cc: Michal Hocko 
Cc: Paolo Bonzini 
Cc: Pedro Falcato 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm, compaction: rename compact_control->rescan to finish_pageblock

2023-02-03T06:33:29+00:00

Patch series "Fix excessive CPU usage during compaction".

Commit 7efc3b726103 ("mm/compaction: fix set skip in fast_find_migrateblock")
fixed a problem where pageblocks found by fast_find_migrateblock() were
ignored. Unfortunately there were numerous bug reports complaining about high
CPU usage and massive stalls once 6.1 was released. Due to the severity,
the patch was reverted by Vlastimil as a short-term fix[1] to -stable.		

The underlying problem for each of the bugs is suspected to be the
repeated scanning of the same pageblocks.  This series should guarantee
forward progress even with commit 7efc3b726103.  More information is in
the changelog for patch 4.

[1] http://lore.kernel.org/r/20230113173345.9692-1-vbabka@suse.cz


This patch (of 4):

The rescan field was not well named albeit accurate at the time.  Rename
the field to finish_pageblock to indicate that the remainder of the
pageblock should be scanned regardless of COMPACT_CLUSTER_MAX.  The intent
is that pageblocks with transient failures get marked for skipping to
avoid revisiting the same pageblock.

Link: https://lkml.kernel.org/r/20230125134434.18017-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman 
Cc: Chuyi Zhou 
Cc: Jiri Slaby 
Cc: Maxim Levitsky 
Cc: Michal Hocko 
Cc: Paolo Bonzini 
Cc: Pedro Falcato 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm: compaction: avoid fragmentation score calculation for empty zones

2023-02-03T06:32:54+00:00

There is no need to calculate the fragmentation score for empty zones.

Link: https://lkml.kernel.org/r/100331ad9d274a9725e687b00d85d75d7e4a17c7.1673342761.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton

mm: compaction: add missing kcompactd wakeup trace event

2023-02-03T06:32:54+00:00

Add missing kcompactd wakeup trace event for proactive compaction,
meanwhile use order = -1 and the highest zone index of the pgdat for the
kcompactd wakeup trace event by proactive compaction.

Link: https://lkml.kernel.org/r/cbf8097a2d8a1b6800991f2a21575550d3613ce6.1673342761.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton

mm: compaction: count the migration scanned pages events for proactive compaction

2023-02-03T06:32:53+00:00

The proactive compaction will reuse per-node kcompactd threads, so we
should also count the KCOMPACTD_MIGRATE_SCANNED and KCOMPACTD_FREE_SCANNED
events for proactive compaction.

Link: https://lkml.kernel.org/r/b7f1ece1adc17defa47e3667b5f9fd61f496517a.1673342761.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton

mm: compaction: move list validation into compact_zone()

2023-02-03T06:32:53+00:00

Move the cc.freepages and cc.migratepages list validation into compact_zone()
to remove some duplicate code.

Link: https://lkml.kernel.org/r/15cf54f7d762e87b04ac3cc74536f7d1ebbcd8cd.1673342761.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang 
Cc: Matthew Wilcox 
Signed-off-by: Andrew Morton