<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/mm/percpu.c, branch v6.7-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2023-11-03T05:38:47+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-11-03T05:38:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ecae0bd5173b1014f95a14a8dfbe40ec10367dcf'/>
<id>ecae0bd5173b1014f95a14a8dfbe40ec10367dcf</id>
<content type='text'>
Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Kemeng Shi has contributed some compation maintenance work in the
     series 'Fixes and cleanups to compaction'

   - Joel Fernandes has a patchset ('Optimize mremap during mutual
     alignment within PMD') which fixes an obscure issue with mremap()'s
     pagetable handling during a subsequent exec(), based upon an
     implementation which Linus suggested

   - More DAMON/DAMOS maintenance and feature work from SeongJae Park i
     the following patch series:

	mm/damon: misc fixups for documents, comments and its tracepoint
	mm/damon: add a tracepoint for damos apply target regions
	mm/damon: provide pseudo-moving sum based access rate
	mm/damon: implement DAMOS apply intervals
	mm/damon/core-test: Fix memory leaks in core-test
	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval

   - In the series 'Do not try to access unaccepted memory' Adrian
     Hunter provides some fixups for the recently-added 'unaccepted
     memory' feature. To increase the feature's checking coverage. 'Plug
     a few gaps where RAM is exposed without checking if it is
     unaccepted memory'

   - In the series 'cleanups for lockless slab shrink' Qi Zheng has done
     some maintenance work which is preparation for the lockless slab
     shrinking code

   - Qi Zheng has redone the earlier (and reverted) attempt to make slab
     shrinking lockless in the series 'use refcount+RCU method to
     implement lockless slab shrink'

   - David Hildenbrand contributes some maintenance work for the rmap
     code in the series 'Anon rmap cleanups'

   - Kefeng Wang does more folio conversions and some maintenance work
     in the migration code. Series 'mm: migrate: more folio conversion
     and unification'

   - Matthew Wilcox has fixed an issue in the buffer_head code which was
     causing long stalls under some heavy memory/IO loads. Some cleanups
     were added on the way. Series 'Add and use bdev_getblk()'

   - In the series 'Use nth_page() in place of direct struct page
     manipulation' Zi Yan has fixed a potential issue with the direct
     manipulation of hugetlb page frames

   - In the series 'mm: hugetlb: Skip initialization of gigantic tail
     struct pages if freed by HVO' has improved our handling of gigantic
     pages in the hugetlb vmmemmep optimizaton code. This provides
     significant boot time improvements when significant amounts of
     gigantic pages are in use

   - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code
     rationalization and folio conversions in the hugetlb code

   - Yin Fengwei has improved mlock()'s handling of large folios in the
     series 'support large folio for mlock'

   - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has
     added statistics for memcg v1 users which are available (and
     useful) under memcg v2

   - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
     prctl so that userspace may direct the kernel to not automatically
     propagate the denial to child processes. The series is named 'MDWE
     without inheritance'

   - Kefeng Wang has provided the series 'mm: convert numa balancing
     functions to use a folio' which does what it says

   - In the series 'mm/ksm: add fork-exec support for prctl' Stefan
     Roesch makes is possible for a process to propagate KSM treatment
     across exec()

   - Huang Ying has enhanced memory tiering's calculation of memory
     distances. This is used to permit the dax/kmem driver to use 'high
     bandwidth memory' in addition to Optane Data Center Persistent
     Memory Modules (DCPMM). The series is named 'memory tiering:
     calculate abstract distance based on ACPI HMAT'

   - In the series 'Smart scanning mode for KSM' Stefan Roesch has
     optimized KSM by teaching it to retain and use some historical
     information from previous scans

   - Yosry Ahmed has fixed some inconsistencies in memcg statistics in
     the series 'mm: memcg: fix tracking of pending stats updates
     values'

   - In the series 'Implement IOCTL to get and optionally clear info
     about PTEs' Peter Xu has added an ioctl to /proc/&lt;pid&gt;/pagemap
     which permits us to atomically read-then-clear page softdirty
     state. This is mainly used by CRIU

   - Hugh Dickins contributed the series 'shmem,tmpfs: general
     maintenance', a bunch of relatively minor maintenance tweaks to
     this code

   - Matthew Wilcox has increased the use of the VMA lock over
     file-backed page faults in the series 'Handle more faults under the
     VMA lock'. Some rationalizations of the fault path became possible
     as a result

   - In the series 'mm/rmap: convert page_move_anon_rmap() to
     folio_move_anon_rmap()' David Hildenbrand has implemented some
     cleanups and folio conversions

   - In the series 'various improvements to the GUP interface' Lorenzo
     Stoakes has simplified and improved the GUP interface with an eye
     to providing groundwork for future improvements

   - Andrey Konovalov has sent along the series 'kasan: assorted fixes
     and improvements' which does those things

   - Some page allocator maintenance work from Kemeng Shi in the series
     'Two minor cleanups to break_down_buddy_pages'

   - In thes series 'New selftest for mm' Breno Leitao has developed
     another MM self test which tickles a race we had between madvise()
     and page faults

   - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups
     and an optimization to the core pagecache code

   - Nhat Pham has added memcg accounting for hugetlb memory in the
     series 'hugetlb memcg accounting'

   - Cleanups and rationalizations to the pagemap code from Lorenzo
     Stoakes, in the series 'Abstract vma_merge() and split_vma()'

   - Audra Mitchell has fixed issues in the procfs page_owner code's new
     timestamping feature which was causing some misbehaviours. In the
     series 'Fix page_owner's use of free timestamps'

   - Lorenzo Stoakes has fixed the handling of new mappings of sealed
     files in the series 'permit write-sealed memfd read-only shared
     mappings'

   - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
     series 'Batch hugetlb vmemmap modification operations'

   - Some buffer_head folio conversions and cleanups from Matthew Wilcox
     in the series 'Finish the create_empty_buffers() transition'

   - As a page allocator performance optimization Huang Ying has added
     automatic tuning to the allocator's per-cpu-pages feature, in the
     series 'mm: PCP high auto-tuning'

   - Roman Gushchin has contributed the patchset 'mm: improve
     performance of accounted kernel memory allocations' which improves
     their performance by ~30% as measured by a micro-benchmark

   - folio conversions from Kefeng Wang in the series 'mm: convert page
     cpupid functions to folios'

   - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about
     kmemleak'

   - Qi Zheng has improved our handling of memoryless nodes by keeping
     them off the allocation fallback list. This is done in the series
     'handle memoryless nodes more appropriately'

   - khugepaged conversions from Vishal Moola in the series 'Some
     khugepaged folio conversions'"

[ bcachefs conflicts with the dynamically allocated shrinkers have been
  resolved as per Stephen Rothwell in

     https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/

  with help from Qi Zheng.

  The clone3 test filtering conflict was half-arsed by yours truly ]

* tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits)
  mm/damon/sysfs: update monitoring target regions for online input commit
  mm/damon/sysfs: remove requested targets when online-commit inputs
  selftests: add a sanity check for zswap
  Documentation: maple_tree: fix word spelling error
  mm/vmalloc: fix the unchecked dereference warning in vread_iter()
  zswap: export compression failure stats
  Documentation: ubsan: drop "the" from article title
  mempolicy: migration attempt to match interleave nodes
  mempolicy: mmap_lock is not needed while migrating folios
  mempolicy: alloc_pages_mpol() for NUMA policy without vma
  mm: add page_rmappable_folio() wrapper
  mempolicy: remove confusing MPOL_MF_LAZY dead code
  mempolicy: mpol_shared_policy_init() without pseudo-vma
  mempolicy trivia: use pgoff_t in shared mempolicy tree
  mempolicy trivia: slightly more consistent naming
  mempolicy trivia: delete those ancient pr_debug()s
  mempolicy: fix migrate_pages(2) syscall return nr_failed
  kernfs: drop shared NUMA mempolicy hooks
  hugetlbfs: drop shared NUMA mempolicy pretence
  mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Kemeng Shi has contributed some compation maintenance work in the
     series 'Fixes and cleanups to compaction'

   - Joel Fernandes has a patchset ('Optimize mremap during mutual
     alignment within PMD') which fixes an obscure issue with mremap()'s
     pagetable handling during a subsequent exec(), based upon an
     implementation which Linus suggested

   - More DAMON/DAMOS maintenance and feature work from SeongJae Park i
     the following patch series:

	mm/damon: misc fixups for documents, comments and its tracepoint
	mm/damon: add a tracepoint for damos apply target regions
	mm/damon: provide pseudo-moving sum based access rate
	mm/damon: implement DAMOS apply intervals
	mm/damon/core-test: Fix memory leaks in core-test
	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval

   - In the series 'Do not try to access unaccepted memory' Adrian
     Hunter provides some fixups for the recently-added 'unaccepted
     memory' feature. To increase the feature's checking coverage. 'Plug
     a few gaps where RAM is exposed without checking if it is
     unaccepted memory'

   - In the series 'cleanups for lockless slab shrink' Qi Zheng has done
     some maintenance work which is preparation for the lockless slab
     shrinking code

   - Qi Zheng has redone the earlier (and reverted) attempt to make slab
     shrinking lockless in the series 'use refcount+RCU method to
     implement lockless slab shrink'

   - David Hildenbrand contributes some maintenance work for the rmap
     code in the series 'Anon rmap cleanups'

   - Kefeng Wang does more folio conversions and some maintenance work
     in the migration code. Series 'mm: migrate: more folio conversion
     and unification'

   - Matthew Wilcox has fixed an issue in the buffer_head code which was
     causing long stalls under some heavy memory/IO loads. Some cleanups
     were added on the way. Series 'Add and use bdev_getblk()'

   - In the series 'Use nth_page() in place of direct struct page
     manipulation' Zi Yan has fixed a potential issue with the direct
     manipulation of hugetlb page frames

   - In the series 'mm: hugetlb: Skip initialization of gigantic tail
     struct pages if freed by HVO' has improved our handling of gigantic
     pages in the hugetlb vmmemmep optimizaton code. This provides
     significant boot time improvements when significant amounts of
     gigantic pages are in use

   - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code
     rationalization and folio conversions in the hugetlb code

   - Yin Fengwei has improved mlock()'s handling of large folios in the
     series 'support large folio for mlock'

   - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has
     added statistics for memcg v1 users which are available (and
     useful) under memcg v2

   - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
     prctl so that userspace may direct the kernel to not automatically
     propagate the denial to child processes. The series is named 'MDWE
     without inheritance'

   - Kefeng Wang has provided the series 'mm: convert numa balancing
     functions to use a folio' which does what it says

   - In the series 'mm/ksm: add fork-exec support for prctl' Stefan
     Roesch makes is possible for a process to propagate KSM treatment
     across exec()

   - Huang Ying has enhanced memory tiering's calculation of memory
     distances. This is used to permit the dax/kmem driver to use 'high
     bandwidth memory' in addition to Optane Data Center Persistent
     Memory Modules (DCPMM). The series is named 'memory tiering:
     calculate abstract distance based on ACPI HMAT'

   - In the series 'Smart scanning mode for KSM' Stefan Roesch has
     optimized KSM by teaching it to retain and use some historical
     information from previous scans

   - Yosry Ahmed has fixed some inconsistencies in memcg statistics in
     the series 'mm: memcg: fix tracking of pending stats updates
     values'

   - In the series 'Implement IOCTL to get and optionally clear info
     about PTEs' Peter Xu has added an ioctl to /proc/&lt;pid&gt;/pagemap
     which permits us to atomically read-then-clear page softdirty
     state. This is mainly used by CRIU

   - Hugh Dickins contributed the series 'shmem,tmpfs: general
     maintenance', a bunch of relatively minor maintenance tweaks to
     this code

   - Matthew Wilcox has increased the use of the VMA lock over
     file-backed page faults in the series 'Handle more faults under the
     VMA lock'. Some rationalizations of the fault path became possible
     as a result

   - In the series 'mm/rmap: convert page_move_anon_rmap() to
     folio_move_anon_rmap()' David Hildenbrand has implemented some
     cleanups and folio conversions

   - In the series 'various improvements to the GUP interface' Lorenzo
     Stoakes has simplified and improved the GUP interface with an eye
     to providing groundwork for future improvements

   - Andrey Konovalov has sent along the series 'kasan: assorted fixes
     and improvements' which does those things

   - Some page allocator maintenance work from Kemeng Shi in the series
     'Two minor cleanups to break_down_buddy_pages'

   - In thes series 'New selftest for mm' Breno Leitao has developed
     another MM self test which tickles a race we had between madvise()
     and page faults

   - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups
     and an optimization to the core pagecache code

   - Nhat Pham has added memcg accounting for hugetlb memory in the
     series 'hugetlb memcg accounting'

   - Cleanups and rationalizations to the pagemap code from Lorenzo
     Stoakes, in the series 'Abstract vma_merge() and split_vma()'

   - Audra Mitchell has fixed issues in the procfs page_owner code's new
     timestamping feature which was causing some misbehaviours. In the
     series 'Fix page_owner's use of free timestamps'

   - Lorenzo Stoakes has fixed the handling of new mappings of sealed
     files in the series 'permit write-sealed memfd read-only shared
     mappings'

   - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
     series 'Batch hugetlb vmemmap modification operations'

   - Some buffer_head folio conversions and cleanups from Matthew Wilcox
     in the series 'Finish the create_empty_buffers() transition'

   - As a page allocator performance optimization Huang Ying has added
     automatic tuning to the allocator's per-cpu-pages feature, in the
     series 'mm: PCP high auto-tuning'

   - Roman Gushchin has contributed the patchset 'mm: improve
     performance of accounted kernel memory allocations' which improves
     their performance by ~30% as measured by a micro-benchmark

   - folio conversions from Kefeng Wang in the series 'mm: convert page
     cpupid functions to folios'

   - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about
     kmemleak'

   - Qi Zheng has improved our handling of memoryless nodes by keeping
     them off the allocation fallback list. This is done in the series
     'handle memoryless nodes more appropriately'

   - khugepaged conversions from Vishal Moola in the series 'Some
     khugepaged folio conversions'"

[ bcachefs conflicts with the dynamically allocated shrinkers have been
  resolved as per Stephen Rothwell in

     https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/

  with help from Qi Zheng.

  The clone3 test filtering conflict was half-arsed by yours truly ]

* tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits)
  mm/damon/sysfs: update monitoring target regions for online input commit
  mm/damon/sysfs: remove requested targets when online-commit inputs
  selftests: add a sanity check for zswap
  Documentation: maple_tree: fix word spelling error
  mm/vmalloc: fix the unchecked dereference warning in vread_iter()
  zswap: export compression failure stats
  Documentation: ubsan: drop "the" from article title
  mempolicy: migration attempt to match interleave nodes
  mempolicy: mmap_lock is not needed while migrating folios
  mempolicy: alloc_pages_mpol() for NUMA policy without vma
  mm: add page_rmappable_folio() wrapper
  mempolicy: remove confusing MPOL_MF_LAZY dead code
  mempolicy: mpol_shared_policy_init() without pseudo-vma
  mempolicy trivia: use pgoff_t in shared mempolicy tree
  mempolicy trivia: slightly more consistent naming
  mempolicy trivia: delete those ancient pr_debug()s
  mempolicy: fix migrate_pages(2) syscall return nr_failed
  kernfs: drop shared NUMA mempolicy hooks
  hugetlbfs: drop shared NUMA mempolicy pretence
  mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>percpu: scoped objcg protection</title>
<updated>2023-10-25T23:47:11+00:00</updated>
<author>
<name>Roman Gushchin</name>
<email>roman.gushchin@linux.dev</email>
</author>
<published>2023-10-19T22:53:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c63b835d0eafc956c43b8c6605708240ac52b8cd'/>
<id>c63b835d0eafc956c43b8c6605708240ac52b8cd</id>
<content type='text'>
Similar to slab and kmem, switch to a scope-based protection of the objcg
pointer to avoid.

Link: https://lkml.kernel.org/r/20231019225346.1822282-6-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin (Cruise) &lt;roman.gushchin@linux.dev&gt;
Tested-by: Naresh Kamboju &lt;naresh.kamboju@linaro.org&gt;
Acked-by: Shakeel Butt &lt;shakeelb@google.com&gt;
Reviewed-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Dennis Zhou &lt;dennis@kernel.org&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Muchun Song &lt;muchun.song@linux.dev&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Similar to slab and kmem, switch to a scope-based protection of the objcg
pointer to avoid.

Link: https://lkml.kernel.org/r/20231019225346.1822282-6-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin (Cruise) &lt;roman.gushchin@linux.dev&gt;
Tested-by: Naresh Kamboju &lt;naresh.kamboju@linaro.org&gt;
Acked-by: Shakeel Butt &lt;shakeelb@google.com&gt;
Reviewed-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Dennis Zhou &lt;dennis@kernel.org&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Muchun Song &lt;muchun.song@linux.dev&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/percpu.c: introduce pcpu_alloc_size()</title>
<updated>2023-10-20T21:15:06+00:00</updated>
<author>
<name>Hou Tao</name>
<email>houtao1@huawei.com</email>
</author>
<published>2023-10-20T13:31:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b460bc8302f222d346f0c15bba980eb8c36d6278'/>
<id>b460bc8302f222d346f0c15bba980eb8c36d6278</id>
<content type='text'>
Introduce pcpu_alloc_size() to get the size of the dynamic per-cpu
area. It will be used by bpf memory allocator in the following patches.
BPF memory allocator maintains per-cpu area caches for multiple area
sizes and its free API only has the to-be-freed per-cpu pointer, so it
needs the size of dynamic per-cpu area to select the corresponding cache
when bpf program frees the dynamic per-cpu pointer.

Acked-by: Dennis Zhou &lt;dennis@kernel.org&gt;
Signed-off-by: Hou Tao &lt;houtao1@huawei.com&gt;
Link: https://lore.kernel.org/r/20231020133202.4043247-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Introduce pcpu_alloc_size() to get the size of the dynamic per-cpu
area. It will be used by bpf memory allocator in the following patches.
BPF memory allocator maintains per-cpu area caches for multiple area
sizes and its free API only has the to-be-freed per-cpu pointer, so it
needs the size of dynamic per-cpu area to select the corresponding cache
when bpf program frees the dynamic per-cpu pointer.

Acked-by: Dennis Zhou &lt;dennis@kernel.org&gt;
Signed-off-by: Hou Tao &lt;houtao1@huawei.com&gt;
Link: https://lore.kernel.org/r/20231020133202.4043247-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/percpu.c: don't acquire pcpu_lock for pcpu_chunk_addr_search()</title>
<updated>2023-10-20T17:12:54+00:00</updated>
<author>
<name>Hou Tao</name>
<email>houtao1@huawei.com</email>
</author>
<published>2023-10-20T13:31:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=394e6869f0185e89cb815db29bf819474df858ae'/>
<id>394e6869f0185e89cb815db29bf819474df858ae</id>
<content type='text'>
There is no need to acquire pcpu_lock for pcpu_chunk_addr_search():
1) both pcpu_first_chunk &amp; pcpu_reserved_chunk must have been
   initialized before the invocation of free_percpu().
2) The dynamically-created chunk must be valid before the per-cpu
   pointers allocated from it are freed.

So acquire pcpu_lock() after the invocation of pcpu_chunk_addr_search().

Acked-by: Dennis Zhou &lt;dennis@kernel.org&gt;
Signed-off-by: Hou Tao &lt;houtao1@huawei.com&gt;
Link: https://lore.kernel.org/r/20231020133202.4043247-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is no need to acquire pcpu_lock for pcpu_chunk_addr_search():
1) both pcpu_first_chunk &amp; pcpu_reserved_chunk must have been
   initialized before the invocation of free_percpu().
2) The dynamically-created chunk must be valid before the per-cpu
   pointers allocated from it are freed.

So acquire pcpu_lock() after the invocation of pcpu_chunk_addr_search().

Acked-by: Dennis Zhou &lt;dennis@kernel.org&gt;
Signed-off-by: Hou Tao &lt;houtao1@huawei.com&gt;
Link: https://lore.kernel.org/r/20231020133202.4043247-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/percpu.c: print error message too if atomic alloc failed</title>
<updated>2023-08-25T15:04:59+00:00</updated>
<author>
<name>Baoquan He</name>
<email>bhe@redhat.com</email>
</author>
<published>2023-07-28T03:02:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f7d77dfc91f747f64cb00884fd6d7940c3b49fca'/>
<id>f7d77dfc91f747f64cb00884fd6d7940c3b49fca</id>
<content type='text'>
The variable 'err' is assgigned to an error message if atomic alloc
failed, while it has no chance to be printed if is_atomic is true.

Here change to print error message too if atomic alloc failed, while
avoid to call dump_stack() if that case.

Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The variable 'err' is assgigned to an error message if atomic alloc
failed, while it has no chance to be printed if is_atomic is true.

Here change to print error message too if atomic alloc failed, while
avoid to call dump_stack() if that case.

Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/percpu.c: optimize the code in pcpu_setup_first_chunk() a little bit</title>
<updated>2023-08-25T15:04:59+00:00</updated>
<author>
<name>Baoquan He</name>
<email>bhe@redhat.com</email>
</author>
<published>2023-07-22T01:14:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7ee1e758bebe13d96217bcfd5230892ed44760e7'/>
<id>7ee1e758bebe13d96217bcfd5230892ed44760e7</id>
<content type='text'>
This removes the need of local varibale 'chunk', and optimize the code
calling pcpu_alloc_first_chunk() to initialize reserved chunk and
dynamic chunk to make it simpler.

Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
[Dennis: reworded first chunk init comment]
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This removes the need of local varibale 'chunk', and optimize the code
calling pcpu_alloc_first_chunk() to initialize reserved chunk and
dynamic chunk to make it simpler.

Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
[Dennis: reworded first chunk init comment]
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/percpu.c: remove redundant check</title>
<updated>2023-08-25T15:04:59+00:00</updated>
<author>
<name>Baoquan He</name>
<email>bhe@redhat.com</email>
</author>
<published>2023-07-21T13:17:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5b672085e70c2ea40f4c9d6a23848079bf0ff700'/>
<id>5b672085e70c2ea40f4c9d6a23848079bf0ff700</id>
<content type='text'>
The conditional check "(ai-&gt;dyn_size &lt; PERCPU_DYNAMIC_EARLY_SIZE) has
covered the check '(!ai-&gt;dyn_size)'.

Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The conditional check "(ai-&gt;dyn_size &lt; PERCPU_DYNAMIC_EARLY_SIZE) has
covered the check '(!ai-&gt;dyn_size)'.

Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/percpu: Remove some local variables in pcpu_populate_pte</title>
<updated>2023-08-25T15:04:59+00:00</updated>
<author>
<name>Bibo Mao</name>
<email>maobibo@loongson.cn</email>
</author>
<published>2023-07-12T03:16:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=41fd59b7f9bdde2a473450680411c2016017b992'/>
<id>41fd59b7f9bdde2a473450680411c2016017b992</id>
<content type='text'>
In function pcpu_populate_pte there are already variable defined,
it can be reused for later use, here remove duplicated local
variables.

Signed-off-by: Bibo Mao &lt;maobibo@loongson.cn&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In function pcpu_populate_pte there are already variable defined,
it can be reused for later use, here remove duplicated local
variables.

Signed-off-by: Bibo Mao &lt;maobibo@loongson.cn&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: memcontrol: rename memcg_kmem_enabled()</title>
<updated>2023-02-17T04:43:56+00:00</updated>
<author>
<name>Roman Gushchin</name>
<email>roman.gushchin@linux.dev</email>
</author>
<published>2023-02-13T19:29:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f7a449f779608efe1941a0e0c4bd7b5f57000be7'/>
<id>f7a449f779608efe1941a0e0c4bd7b5f57000be7</id>
<content type='text'>
Currently there are two kmem-related helper functions with a confusing
semantics: memcg_kmem_enabled() and mem_cgroup_kmem_disabled().

The problem is that an obvious expectation
memcg_kmem_enabled() == !mem_cgroup_kmem_disabled(),
can be false.

mem_cgroup_kmem_disabled() is similar to mem_cgroup_disabled(): it returns
true only if CONFIG_MEMCG_KMEM is not set or the kmem accounting is
disabled using a boot time kernel option "cgroup.memory=nokmem".  It never
changes the value dynamically.

memcg_kmem_enabled() is different: it always returns false until the first
non-root memory cgroup will get online (assuming the kernel memory
accounting is enabled).  It's goal is to improve the performance on
systems without the cgroupfs mounted/memory controller enabled or on the
systems with only the root memory cgroup.

To make things more obvious and avoid potential bugs, let's rename
memcg_kmem_enabled() to memcg_kmem_online().

Link: https://lkml.kernel.org/r/20230213192922.1146370-1-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin &lt;roman.gushchin@linux.dev&gt;
Acked-by: Muchun Song &lt;songmuchun@bytedance.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Dennis Zhou &lt;dennis@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently there are two kmem-related helper functions with a confusing
semantics: memcg_kmem_enabled() and mem_cgroup_kmem_disabled().

The problem is that an obvious expectation
memcg_kmem_enabled() == !mem_cgroup_kmem_disabled(),
can be false.

mem_cgroup_kmem_disabled() is similar to mem_cgroup_disabled(): it returns
true only if CONFIG_MEMCG_KMEM is not set or the kmem accounting is
disabled using a boot time kernel option "cgroup.memory=nokmem".  It never
changes the value dynamically.

memcg_kmem_enabled() is different: it always returns false until the first
non-root memory cgroup will get online (assuming the kernel memory
accounting is enabled).  It's goal is to improve the performance on
systems without the cgroupfs mounted/memory controller enabled or on the
systems with only the root memory cgroup.

To make things more obvious and avoid potential bugs, let's rename
memcg_kmem_enabled() to memcg_kmem_online().

Link: https://lkml.kernel.org/r/20230213192922.1146370-1-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin &lt;roman.gushchin@linux.dev&gt;
Acked-by: Muchun Song &lt;songmuchun@bytedance.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Dennis Zhou &lt;dennis@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/percpu.c: remove the lcm code since block size is fixed at page size</title>
<updated>2022-11-08T06:59:18+00:00</updated>
<author>
<name>Baoquan He</name>
<email>bhe@redhat.com</email>
</author>
<published>2022-10-24T08:14:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3289e0533e70aafa9fb6d128fd4452db1b8befe8'/>
<id>3289e0533e70aafa9fb6d128fd4452db1b8befe8</id>
<content type='text'>
Since commit b239f7daf553 ("percpu: set PCPU_BITMAP_BLOCK_SIZE to
PAGE_SIZE"), the PCPU_BITMAP_BLOCK_SIZE has been set to page size
fixedly. So the lcm code in pcpu_alloc_first_chunk() doesn't make
sense any more, clean it up.

Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Since commit b239f7daf553 ("percpu: set PCPU_BITMAP_BLOCK_SIZE to
PAGE_SIZE"), the PCPU_BITMAP_BLOCK_SIZE has been set to page size
fixedly. So the lcm code in pcpu_alloc_first_chunk() doesn't make
sense any more, clean it up.

Signed-off-by: Baoquan He &lt;bhe@redhat.com&gt;
Signed-off-by: Dennis Zhou &lt;dennis@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
