<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/git/stable/linux.git/mm/vmscan.c, branch linux-7.2.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<id>https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/atom?h=linux-7.2.y</id>
<link rel='self' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/atom?h=linux-7.2.y'/>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/'/>
<updated>2026-07-29T00:37:33+00:00</updated>
<entry>
<title>mm: vmscan: abort proactive reclaim early when freezing for suspend</title>
<updated>2026-07-29T00:37:33+00:00</updated>
<author>
<name>Richard Chang</name>
<email>richardycc@google.com</email>
</author>
<published>2026-07-20T04:41:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dc37771a43d4a8762f05060c28463b0c20e6dc9b'/>
<id>urn:sha1:dc37771a43d4a8762f05060c28463b0c20e6dc9b</id>
<content type='text'>
Proactive reclaim (triggered via memory.reclaim or node sysfs) checks for
pending signals in its outer loop in user_proactive_reclaim().  However,
the inner reclaim loops—specifically scanning cgroups in shrink_many()
and evicting/aging folios in try_to_shrink_lruvec()—can run for a long
time before returning to the outer loop, especially on systems with many
cgroups or large memory sizes.

During system suspend, the PM freezer attempts to freeze all tasks by
sending fake signals (setting TIF_SIGPENDING).  Because the inner loops do
not check for pending signals, the proactive reclaim task can remain stuck
in kernel space for seconds, failing to enter the refrigerator in a timely
manner.  This leads to suspend failures due to freeze timeouts, a behavior
observed on Android devices.

This latency issue is specific to proactive reclaim because of its large,
user-defined reclaim targets (could be gigabytes).  Since commit
287d5fedb377 ("mm: memcg: use larger batches for proactive reclaim"),
proactive reclaim uses larger decaying batch sizes (starting at 1/4 of the
remaining target) to maintain throughput.  This keeps the task in the
inner reclaim loop for extended periods.  In contrast, reactive reclaim
(global/memcg) uses small targets (SWAP_CLUSTER_MAX, typically 32 pages),
allowing it to return to the outer loop and check signals frequently.

To fix this, add a signal_pending() check to should_abort_scan() for
proactive reclaim paths.  Since should_abort_scan() is called within the
inner scanning and eviction loops, this allows proactive reclaim to abort
early and return to the outer loop in user_proactive_reclaim().

Additionally, return -ERESTARTSYS instead of -EINTR in
user_proactive_reclaim().  When interrupted by system suspend, returning
-ERESTARTSYS allows the task to enter the refrigerator and automatically
restart the syscall upon resume, making the freezer transparent to
userspace.  For real signals, the signal layer will either restart the
syscall (if SA_RESTART is set) or return -EINTR to userspace.

This fix specifically targets Multi-Gen LRU (MGLRU).  Classic LRU's scan
targets per iteration are strictly bounded by get_scan_count(), which
ensures it returns to the outer loop more frequently.

The check in should_abort_scan() is limited to proactive reclaim
(sc-&gt;proactive) to avoid inadvertently affecting reactive reclaim paths,
and is wrapped in unlikely() as it is a slow path.

Link: https://lore.kernel.org/20260720044103.905191-1-richardycc@google.com
Fixes: 287d5fedb377 ("mm: memcg: use larger batches for proactive reclaim")
Fixes: 94968384dde1 ("memcg: introduce per-memcg reclaim interface")
Suggested-by: Michal Hocko &lt;mhocko@suse.com&gt;
Suggested-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Signed-off-by: Richard Chang &lt;richardycc@google.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Axel Rasmussen &lt;axelrasmussen@google.com&gt;
Cc: Barry Song &lt;baohua@kernel.org&gt;
Cc: David Hildenbrand &lt;david@kernel.org&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Kairui Song &lt;kasong@tencent.com&gt;
Cc: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Cc: Martin Liu &lt;liumartin@google.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Shakeel Butt &lt;shakeel.butt@linux.dev&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: T.J. Mercier &lt;tjmercier@google.com&gt;
Cc: Wei Xu &lt;weixugc@google.com&gt;
Cc: Yuanchu Xie &lt;yuanchu@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm: mglru: fix stale batch updates after memcg reparenting</title>
<updated>2026-07-21T00:41:28+00:00</updated>
<author>
<name>Qi Zheng</name>
<email>zhengqi.arch@bytedance.com</email>
</author>
<published>2026-07-10T15:43:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=de4660898b7aa7e03d3b120a6bfa6b26211e4e77'/>
<id>urn:sha1:de4660898b7aa7e03d3b120a6bfa6b26211e4e77</id>
<content type='text'>
The mglru page table walker batches per-generation size deltas in
walk-&gt;nr_pages while walking page tables without holding the lruvec lock. 
The reset_batch_size() later folds those deltas into walk-&gt;lruvec under
the lruvec lock.

The page table walker can run concurrently with the memcg reparenting path
as follows:

CPU0                           CPU1
====                           ====

walk_mm
--&gt; walk_page_range
    --&gt; update_batch_size
        --&gt; walk-&gt;nr_pages += delta

                              mem_cgroup_css_offline
                              --&gt; memcg_reparent_objcgs
                                  --&gt; lock lruvec
                                      lru_gen_reparent_memcg
                                      --&gt; reparent child folios to parent
                                      unlock lruvec

    lock lruvec
    reset_batch_size
    --&gt; child lrugen-&gt;nr_pages += delta

This will trigger the following warning in lru_gen_exit_memcg():

	VM_WARN_ON_ONCE(memchr_inv(lruvec-&gt;lrugen.nr_pages, 0,
				   sizeof(lruvec-&gt;lrugen.nr_pages)));

And the user-visible impact of underestimated nr_pages in MGLRU was
premature OOMs because MGLRU does not try to reclaim memory when nr_pages
reaches zero, but there are still more pages.

To fix it, make reset_batch_size() check CSS_DYING under RCU before
flushing the pending batch.  A non-dying memcg keeps the original lruvec
stable against RCU-delayed offlining; a dying memcg redirects the deltas
to the first non-dying ancestor.

Link: https://lore.kernel.org/20260710154318.75388-1-qi.zheng@linux.dev
Fixes: f304652609ea ("mm: vmscan: prepare for reparenting MGLRU folios")
Signed-off-by: Qi Zheng &lt;zhengqi.arch@bytedance.com&gt;
Reported-by: Peiyang He &lt;peiyang_he@smail.nju.edu.cn&gt;
Closes: https://lore.kernel.org/all/5A9E929D82717101+12fcf643-efb8-4b9a-a53a-1e28cc894f0b@smail.nju.edu.cn
Reviewed-by: Harry Yoo (Oracle) &lt;harry@kernel.org&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Acked-by: Shakeel Butt &lt;shakeel.butt@linux.dev&gt;
Cc: Axel Rasmussen &lt;axelrasmussen@google.com&gt;
Cc: Barry Song &lt;baohua@kernel.org&gt;
Cc: David Hildenbrand &lt;david@kernel.org&gt;
Cc: Kairui Song &lt;kasong@tencent.com&gt;
Cc: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Muchun Song &lt;muchun.song@linux.dev&gt;
Cc: Roman Gushchin &lt;roman.gushchin@linux.dev&gt;
Cc: Wei Xu &lt;weixugc@google.com&gt;
Cc: Yuanchu Xie &lt;yuanchu@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'mm-stable-2026-06-23-08-55' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2026-06-23T19:03:44+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-06-23T19:03:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a1a8bab74176eed204a3139ab7ad840caa3d73b8'/>
<id>urn:sha1:a1a8bab74176eed204a3139ab7ad840caa3d73b8</id>
<content type='text'>
Pull more MM updates from Andrew Morton:

 - "khugepaged: add mTHP collapse support" (Nico Pache)

   Provide khugepaged with the capability to collapse anonymous memory
   regions to mTHPs

 - "Remove CONFIG_READ_ONLY_THP_FOR_FS and enable file THP for writable
   files" (Zi Yan)

   Remove the READ_ONLY_THP_FOR_FS check in file_thp_enabled(), so that
   khugepaged and MADV_COLLAPSE can run on filesystems with PMD THP
   pagecache support even without READ_ONLY_THP_FOR_FS enabled

 - "make MM selftests more CI friendly" (Mike Rapoport)

   General fixes and cleanups to the MM selftests. Also move more MM
   selftests under the kselftest framework, making them more amenable to
   ongoing CI testing

 - "selftests/mm: fix failures and robustness improvements" and
   "selftests/mm: assorted fixes for hmm-tests" (Sayali Patil)

   Fix several issues in MM selftests which were revealed by powerpc 64k
   pagesize

* tag 'mm-stable-2026-06-23-08-55' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (118 commits)
  Revert "mm: limit filemap_fault readahead to VMA boundaries"
  mm/vmscan: pass NULL to trace vmscan node reclaim
  mm: use mapping_mapped to simplify the code
  selftests/mm: fix exclusive_cow test fork() handling
  selftests/mm: remove hardcoded THP sizing assumptions in hmm tests
  selftests/mm: allow PUD-level entries in compound testcase of hmm tests
  mm/gup_test: reject wrapped user ranges
  mm/page_frag: reject invalid CPUs in page_frag_test
  mm/damon/core: always put unsuccessfully committed target pids
  mm: page_isolation: avoid unsafe folio reads while scanning compound pages
  mm/shrinker: do not hold RCU lock in shrinker_debugfs_count_show()
  selftests: mm: fix and speedup "droppable" test
  mm: merge writeout into pageout
  MAINTAINERS: add Hao Ge as reviewer for codetag and alloc_tag
  selftests/mm: clarify alternate unmapping in compaction_test
  selftests/mm: move hwpoison setup into run_test() and silence modprobe output for memory-failure category
  selftests/mm: skip uffd-stress test when nr_pages_per_cpu is zero
  selftests/mm: skip uffd-wp-mremap if UFFD write-protect is unsupported
  selftests/mm: ensure destination is hugetlb-backed in hugetlb-mremap
  selftest/mm: register existing mapping with userfaultfd in hugetlb-mremap
  ...
</content>
</entry>
<entry>
<title>mm/vmscan: pass NULL to trace vmscan node reclaim</title>
<updated>2026-06-21T18:37:38+00:00</updated>
<author>
<name>Ben Dooks</name>
<email>ben.dooks@codethink.co.uk</email>
</author>
<published>2026-06-16T09:59:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=44238b122ae834ac52748e59809a139a2cb8409b'/>
<id>urn:sha1:44238b122ae834ac52748e59809a139a2cb8409b</id>
<content type='text'>
The tracepoint for node relcaims takes a `struct mem_cgroup *`
as the third argument, so pass NULL instead of 0 to fix warning
about using an integer as a pointer.

Fixes the following warnings:

mm/vmscan.c:6753:66: warning: Using plain integer as NULL pointer
mm/vmscan.c:6757:58: warning: Using plain integer as NULL pointer
mm/vmscan.c:7818:60: warning: Using plain integer as NULL pointer

Link: https://lore.kernel.org/20260616095906.210016-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks &lt;ben.dooks@codethink.co.uk&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm: merge writeout into pageout</title>
<updated>2026-06-21T18:37:35+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2026-06-01T11:34:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6f64c06f43098ea0aa0a67d0ad15124b5d2ba0fe'/>
<id>urn:sha1:6f64c06f43098ea0aa0a67d0ad15124b5d2ba0fe</id>
<content type='text'>
writeout is only called from pageout, and a straight flow at the end, so
merge the two functions.

Link: https://lore.kernel.org/20260601113449.3464734-3-hch@lst.de
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Baoquan He &lt;baoquan.he@linux.dev&gt;
Reviewed-by: Nhat Pham &lt;nphamcs@gmail.com&gt;
Acked-by: David Hildenbrand (Arm) &lt;david@kernel.org&gt;
Cc: Chris Li &lt;chrisl@kernel.org&gt;
Cc: Kairui Song &lt;kasong@tencent.com&gt;
Cc: Kemeng Shi &lt;shikemeng@huaweicloud.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2026-06-19T17:14:34+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-06-19T17:14:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a552c81ff4a16738ca5a44a177d552eb38d552ce'/>
<id>urn:sha1:a552c81ff4a16738ca5a44a177d552eb38d552ce</id>
<content type='text'>
Pull MM updates from Andrew Morton:

 - "selftests/mm: clean up build output and verbosity" (Li Wang)

   Remove some noise from the MM selftests build

 - "mm: Free contiguous order-0 pages efficiently" (Ryan Roberts)

   Speed up the freeing of a batch of 0-order pages by first scanning
   them for coalescing opportunities. This is applicable to vfree() and
   to the releasing of frozen pages

 - "mm/damon: introduce DAMOS failed region quota charge ratio"
   (SeongJae Park)

   Address a DAMOS usability issue: The DAMOS quota often exhausts
   prematurely because it charges for all memory attempted, causing slow
   and inconsistent performance when actions fail on unreclaimable
   memory.

   To fix this, a new feature lets users set a smaller, flexible quota
   charge ratio (via a numerator and denominator) for failed regions.
   Since failed actions cause less overhead, reducing their quota cost
   ensures more predictable and efficient DAMOS processing

 - "selftests/cgroup: improve zswap tests robustness and support large
   page sizes" (Li Wang)

   Fix various spurious failures and improves the overall robustness of
   the cgroup zswap selftests

 - "fix MAP_DROPPABLE not supported errno" (Anthony Yznaga)

   Fix an issue in the mlock selftests on arm32

 - "mm: huge_memory: clean up defrag sysfs with shared" (Breno Leitao)

   Some maintenance work in the huge_memory code

 - "treewide: fixup gfp_t printks" (Brendan Jackman)

   Use the special vprintf() gfp_t conversion in various places

 - "mm: Fix vmemmap optimization accounting and initialization" (Muchun
   Song)

   Fix several bugs in the vmemmap optimization, mainly around incorrect
   page accounting and memmap initialization in the DAX and memory
   hotplug paths. It also fixes pageblock migratetype initialization and
   struct page initialization for ZONE_DEVICE compound pages

 - "mm/damon: repost non-hotfix reviewed patches in damon/next tree"

   A sprinkle of unrelated minor bugfixes for DAMON

 - "mm: remove page_mapped()" (David Hildenbrand)

   Remove this function from the tree, replacing it with folio_mapped()

 - "mm/damon: let DAMON be paused and resumed" (SeongJae Park)

   Allow DAMON to be paused and resumed without losing its current state

 - "kasan: hw_tags: Disable tagging for stack and page-tables" (Muhammad
   Usama Anjum)

   Simplify and speed up kasan by removing its ineffective tagging of
   stacks and page tables

 - "mm/damon/reclaim,lru_sort: monitor all system rams by default"
   (SeongJae Park)

   Simplify deployment on diverse hardware like NUMA systems by updating
   DAMON_RECLAIM and DAMON_LRU_SORT to automatically monitor the
   physical address range covering all System RAM areas by default,
   replacing the overly restrictive behavior that only targeted the
   single largest memory block to save on negligible overhead

 - "mm/damon/sysfs: document filters/ directory as deprecated" (SeongJae
   Park)

   Update some DAMON docs

 - "mm: use spinlock guards for zone lock" (Dmitry Ilvokhin)

   Switch zone-&gt;lock handling over to using the guard() mechanisms

 - "mm/filemap: tighten mmap_miss hit accounting" (fujunjie)

   Fix a flaw where the mmap_miss counter over-credited page cache hits
   during fault-arounds and page-fault retries. This results in
   significant reduction of redundant synchronous mmap readahead I/O,
   drastically cutting down execution time and gigabytes read for sparse
   random or strided memory access workloads

 - "selftests/cgroup: Fix false positive failures in test_percpu_basic"
   (Li Wang)

   Fix a couple of false-positives in the cgroup kmem selftests

 - "mm/damon/reclaim: support monitoring intervals auto-tuning"
   (SeongJae Park)

   Add a new parameter to DAMON permitting DAMON_RECLAIM to
   automatically tune DAMON's sampling and aggregation intervals

 - "mm/damon/stat: add kdamond_pid parameter" (SeongJae Park)

   Change DAMON_STAT to provide the pid of its kdamond

 - "mm/kmemleak: dedupe verbose scan output" (Breno Leitao)

   Remove large amounts of duplicated backtraces from the verbose-mode
   kmemleak output

 - "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 1)" (David
   Hildenbrand)

   Reduce our use of CONFIG_HAVE_BOOTMEM_INFO_NODE, with a view to
   removing it entirely in a later series

 - "mm/damon: validate min_region_size to be power of 2" (Liew Rui Yan)

   Prevent users from passing a non-power-of-2 value of `addr_unit', as
   this later results in undesirable behavior

 - "mm: document read_pages and simplify usage" (Frederick Mayle)

 - "tools/mm/page-types: Fix misc bugs" (Ye Liu)

   Fix three issues in tools/mm/page-types.c

 - "mm: misc cleanups from __GFP_UNMAPPED series" (Brendan Jackman)

   Implement several cleanups in the page allocator and related code

 - "mm, swap: swap table phase IV: unify allocation" (Kairui Song)

   Unify the allocation and charging of anon and shmem swap in folios,
   provides better synchronization, consolidates the metadata
   management, hence dropping the static array and map, and improves
   performance

 - "mm/damon: introduce data attributes monitoring" (SeongJae Park(

   Extend DAMON to monitor general data attributes other than accesses

 - "mm/vmalloc: free unused pages on vrealloc() shrink" (Shivam Kalra)

   Implement the TODO in vrealloc() to unmap and free unused pages when
   shrinking across a page boundary

 - "mm/damon: documentation and comment fixes" (niecheng)

 - "remove mmap_action success, error hooks" (Lorenzo Stoakes)

   Eliminate custom hooks from mmap_action by removing the problematic
   success_hook which allowed drivers to improperly access uninitialized
   VMAs. It replaces the error_hook with a simple error-code field and
   updates the memory char driver accordingly

 - "mm/damon: minor improvements for code readability and tests"
   (SeongJae Park)

 - "mm/damon: fix macro arguments and clarify quota goals doc" (Maksym
   Shcherba)

 - "userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c" (Mike
   Rapoport)

 - "mm/mglru: improve reclaim loop and dirty folio" (Kairui Song and
   others)

   Clean up and slightly improves MGLRU's reclaim loop and dirty
   writeback handling. Large performance improvements are measured

 - "use vma locks for proc/pid/{smaps|numa_maps} reads" (Suren
   Baghdasaryan)

   Use per-vma locks when reading /proc/pid/smaps and numa_maps similar
   to reduce contention on central mmap_lock

 - "refactors thpsize_shmem_enabled_store() and thpsize_shmem_enabled_show()"
   (Ran Xiaokai)

   Some cleanup work in the THP code

 - "selftests/memfd: fix compilation warnings" (Konstantin Khorenko)

   Fix a few build glitches in the memfd selftest code.

 - "memcg: shrink obj_stock_pcp and cache multiple objcgs" (Shakeel
   Butt)

   Resolve a 68% performance regression caused by NUMA-node cache
   thrashing around struct obj_stock_pcp by shrinking its existing
   fields and expanding it into a multi-slot array that caches up to
   five obj_cgroup pointers per CPU, allowing per-node variants of the
   same memcg to coexist within a single 64-byte cache line.

 - "zram: writeback fixes" (Sergey Senozhatsky)

   address a couple of unrelated zram writeback issues

 - "mm: switch THP shrinker to list_lru" (Johannes Weiner)

   Resolve NUMA-awareness issues and streamlines callsite interaction by
   refactoring and extending the list_lru API to completely replace the
   complex, open-coded deferred split queue for Transparent Huge Pages

 - "mm: improve large folio readahead for exec memory" (Usama Arif)

   Improve large-folio readahead on systems like 64K-page arm64 by
   preventing the mmap_miss check from permanently disabling
   target-oriented VM_EXEC readahead, and by generalizing the
   force_thp_readahead gate to support mappings with any usefully large
   maximum folio order under the cache cap.

 - "userfaultfd/pagemap: pre-existing fixes" (Kiryl Shutsemau)

   Fix a bunch of minor issues in the userfaultfd/pagemap, all of which
   were flagged by Sashiko review of proposed new material

 - "mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and
   vmemmap_check_pmd()" (Muchun Song)

   Provide generic versions of these two functions so the four
   arch-specific implementations can be removed.

 - "mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap
   device" (Youngjun Park)

   Address a uswsusp-vs-swapoff race and reduces the swap device
   reference taking/releasing frequency.

 - "mm/hmm: A fix and a selftest" (Dev Jain)

* tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
  selftests/mm/hmm-tests: test pagemap reads of PMD device-private entries
  fs/proc/task_mmu: do not warn on seeing non-migration pmd entry
  lib/test_hmm: check alloc_page_vma() return value and handle OOM
  mm/compaction: cap compact_gap() at COMPACT_CLUSTER_MAX
  mm/swap: remove redundant swap device reference in alloc/free
  mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device
  mm/filemap: use folio_next_index() for start
  vmalloc: fix NULL pointer dereference in is_vm_area_hugepages()
  sparc/mm: drop vmemmap_check_pmd helper and use generic code
  loongarch/mm: drop vmemmap_check_pmd helper and use generic code
  riscv/mm: drop vmemmap_pmd helpers and use generic code
  arm64/mm: drop vmemmap_pmd helpers and use generic code
  mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd()
  rust: page: mark Page::nid as inline
  userfaultfd: build __VMA_UFFD_FLAGS from config-gated masks
  userfaultfd: gate must_wait writability check on pte_present()
  mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade
  fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole()
  fs/proc/task_mmu: use huge_page_size() in pagemap_scan_hugetlb_entry()
  fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race
  ...
</content>
</entry>
<entry>
<title>mm/compaction: cap compact_gap() at COMPACT_CLUSTER_MAX</title>
<updated>2026-06-09T01:21:32+00:00</updated>
<author>
<name>JP Kobryn</name>
<email>jp.kobryn@linux.dev</email>
</author>
<published>2026-06-04T06:17:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=32a2b73ec232b284b029d34bcfaa9a7f424151d2'/>
<id>urn:sha1:32a2b73ec232b284b029d34bcfaa9a7f424151d2</id>
<content type='text'>
compact_gap() returns 2 &lt;&lt; order, which is used as watermark headroom in
__compaction_suitable() and as a threshold in kswapd reclaim decisions. 
The computed value scales exponentially by order.  For order-9 THP
allocations this evaluates to 1024 pages, but the compaction free
scanner's working set is bounded by COMPACT_CLUSTER_MAX (32 pages).  The
scanner stops isolating free pages once it matches the migration batch. 
The current gap over-reserves by 32x.

On fragmented production hosts, kswapd will try to reclaim up to the gap,
but it only reaches that threshold in 18% of attempts.  As a result,
reclaim continues in the majority of cases despite many lower-order free
pages being available.  The over-sized gap also causes 46% of order-9
compaction suitability checks to fail unnecessarily: the zone has
sufficient free pages for the scanner to operate, but not enough to clear
the inflated threshold.

Cap compact_gap() at COMPACT_CLUSTER_MAX so the watermark headroom
reflects the scanner's actual capacity.  This function is used by two key
heuristics.  The first is when kswapd can stop high-order reclaim and
downgrade to order-0 balancing, allowing kcompactd to be woken for the
original higher allocation order.  The second is zone suitability
checking, where the smaller gap allows compaction to start sooner.

Note that orders 0-4 are unaffected since their gap is already less than
or equal to COMPACT_CLUSTER_MAX.

A/B test on v6.13-based instagram production hosts (64GB, 60s
measurement):

Unpatched (43 hosts)
pgscan_kswapd (mean/host): ~1.6M
reclaim efficiency (steal/scan): 83.8%
per-compaction success (success/stall): 2.1%
THP success (alloc/alloc+fallback): 4.9%
forced lru_add_drain (mean/host): ~107K

Patched (59 hosts)
pgscan_kswapd (mean/host): ~449K
reclaim efficiency (steal/scan): 91.0%
per-compaction success (success/stall): 28.3%
THP success (alloc/alloc+fallback): 17.2%
forced lru_add_drain (mean/host): ~64K

Additional tests were also performed using a workload of similar shape and
based on mm-new at the time of testing.  Across three 60s runs, the patch
showed improvements consistent with the previous test: reduced kswapd
reclaim and fewer THP fault fallbacks.

Unpatched
kswapd_shrink_node downgrade to order-0 (mean): 0
thp_fault_fallback (mean): 1217
pgscan_kswapd (mean): 6328
pgsteal_kswapd (mean): 5657

Patched
kswapd_shrink_node downgrade to order-0 (mean): 28
thp_fault_fallback (mean): 738
pgscan_kswapd (mean): 3773
pgsteal_kswapd (mean): 3243

Link: https://lore.kernel.org/20260604061725.13800-1-jp.kobryn@linux.dev
Signed-off-by: JP Kobryn (Meta) &lt;jp.kobryn@linux.dev&gt;
Reviewed-by: Vlastimil Babka (SUSE) &lt;vbabka@kernel.org&gt;
Cc: Brendan Jackman &lt;jackmanb@google.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm/vmscan: unify writeback reclaim statistic and throttling</title>
<updated>2026-06-04T21:45:05+00:00</updated>
<author>
<name>Kairui Song</name>
<email>kasong@tencent.com</email>
</author>
<published>2026-04-27T18:07:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=39376b9cac1cef505e1fa9a0a6105cf0de7c6734'/>
<id>urn:sha1:39376b9cac1cef505e1fa9a0a6105cf0de7c6734</id>
<content type='text'>
Currently MGLRU and non-MGLRU handle the reclaim statistic and writeback
handling very differently, especially throttling.  Basically MGLRU just
ignored the throttling part.

Let's just unify this part, use a helper to deduplicate the code so both
setups will share the same behavior.

Test using following reproducer using bash:

  echo "Setup a slow device using dm delay"
  dd if=/dev/zero of=/var/tmp/backing bs=1M count=2048
  LOOP=$(losetup --show -f /var/tmp/backing)
  mkfs.ext4 -q $LOOP
  echo "0 $(blockdev --getsz $LOOP) delay $LOOP 0 0 $LOOP 0 1000" | \
      dmsetup create slow_dev
  mkdir -p /mnt/slow &amp;&amp; mount /dev/mapper/slow_dev /mnt/slow

  echo "Start writeback pressure"
  sync &amp;&amp; echo 3 &gt; /proc/sys/vm/drop_caches
  mkdir /sys/fs/cgroup/test_wb
  echo 128M &gt; /sys/fs/cgroup/test_wb/memory.max
  (echo $BASHPID &gt; /sys/fs/cgroup/test_wb/cgroup.procs &amp;&amp; \
      dd if=/dev/zero of=/mnt/slow/testfile bs=1M count=192)

  echo "Clean up"
  echo "0 $(blockdev --getsz $LOOP) error" | dmsetup load slow_dev
  dmsetup resume slow_dev
  umount -l /mnt/slow &amp;&amp; sync
  dmsetup remove slow_dev

Before this commit, `dd` will get OOM killed immediately if MGLRU is
enabled.  Classic LRU is fine.

After this commit, throttling is now effective and no more spin on LRU or
premature OOM.  Stress test on other workloads also looks good.

Global throttling is not here yet, we will fix that separately later.

Link: https://lore.kernel.org/20260428-mglru-reclaim-v7-15-02fabb92dc43@tencent.com
Signed-off-by: Kairui Song &lt;kasong@tencent.com&gt;
Suggested-by: Chen Ridong &lt;chenridong@huaweicloud.com&gt;
Tested-by: Leno Hou &lt;lenohou@gmail.com&gt;
Reviewed-by: Axel Rasmussen &lt;axelrasmussen@google.com&gt;
Reviewed-by: Baolin Wang &lt;baolin.wang@linux.alibaba.com&gt;
Cc: Barry Song &lt;baohua@kernel.org&gt;
Cc: Chris Li &lt;chrisl@kernel.org&gt;
Cc: David Hildenbrand &lt;david@kernel.org&gt;
Cc: David Stevens &lt;stevensd@google.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Kalesh Singh &lt;kaleshsingh@google.com&gt;
Cc: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Shakeel Butt &lt;shakeel.butt@linux.dev&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Vernon Yang &lt;vernon2gm@gmail.com&gt;
Cc: Wei Xu &lt;weixugc@google.com&gt;
Cc: Yafang &lt;laoar.shao@gmail.com&gt;
Cc: Yuanchu Xie &lt;yuanchu@google.com&gt;
Cc: Yu Zhao &lt;yuzhao@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm/vmscan: remove sc-&gt;unqueued_dirty</title>
<updated>2026-06-04T21:45:05+00:00</updated>
<author>
<name>Kairui Song</name>
<email>kasong@tencent.com</email>
</author>
<published>2026-04-27T18:07:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=183ff2f9ec4875e010c00984374e51a545f6b169'/>
<id>urn:sha1:183ff2f9ec4875e010c00984374e51a545f6b169</id>
<content type='text'>
No one is using it now, just remove it.

Link: https://lore.kernel.org/20260428-mglru-reclaim-v7-14-02fabb92dc43@tencent.com
Signed-off-by: Kairui Song &lt;kasong@tencent.com&gt;
Suggested-by: Axel Rasmussen &lt;axelrasmussen@google.com&gt;
Reviewed-by: Baolin Wang &lt;baolin.wang@linux.alibaba.com&gt;
Reviewed-by: Axel Rasmussen &lt;axelrasmussen@google.com&gt;
Reviewed-by: Barry Song &lt;baohua@kernel.org&gt;
Reviewed-by: Chen Ridong &lt;chenridong@huaweicloud.com&gt;
Cc: Chris Li &lt;chrisl@kernel.org&gt;
Cc: David Hildenbrand &lt;david@kernel.org&gt;
Cc: David Stevens &lt;stevensd@google.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Kalesh Singh &lt;kaleshsingh@google.com&gt;
Cc: Leno Hou &lt;lenohou@gmail.com&gt;
Cc: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Shakeel Butt &lt;shakeel.butt@linux.dev&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Vernon Yang &lt;vernon2gm@gmail.com&gt;
Cc: Wei Xu &lt;weixugc@google.com&gt;
Cc: Yafang &lt;laoar.shao@gmail.com&gt;
Cc: Yuanchu Xie &lt;yuanchu@google.com&gt;
Cc: Yu Zhao &lt;yuzhao@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm/vmscan: remove sc-&gt;file_taken</title>
<updated>2026-06-04T21:45:05+00:00</updated>
<author>
<name>Kairui Song</name>
<email>kasong@tencent.com</email>
</author>
<published>2026-04-27T18:07:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e621a24e10bb07998dab930009eadbd220253d4e'/>
<id>urn:sha1:e621a24e10bb07998dab930009eadbd220253d4e</id>
<content type='text'>
No one is using it now, just remove it.

Link: https://lore.kernel.org/20260428-mglru-reclaim-v7-13-02fabb92dc43@tencent.com
Signed-off-by: Kairui Song &lt;kasong@tencent.com&gt;
Reviewed-by: Axel Rasmussen &lt;axelrasmussen@google.com&gt;
Reviewed-by: Baolin Wang &lt;baolin.wang@linux.alibaba.com&gt;
Reviewed-by: Chen Ridong &lt;chenridong@huaweicloud.com&gt;
Cc: Barry Song &lt;baohua@kernel.org&gt;
Cc: Chris Li &lt;chrisl@kernel.org&gt;
Cc: David Hildenbrand &lt;david@kernel.org&gt;
Cc: David Stevens &lt;stevensd@google.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Kalesh Singh &lt;kaleshsingh@google.com&gt;
Cc: Leno Hou &lt;lenohou@gmail.com&gt;
Cc: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Shakeel Butt &lt;shakeel.butt@linux.dev&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Vernon Yang &lt;vernon2gm@gmail.com&gt;
Cc: Wei Xu &lt;weixugc@google.com&gt;
Cc: Yafang &lt;laoar.shao@gmail.com&gt;
Cc: Yuanchu Xie &lt;yuanchu@google.com&gt;
Cc: Yu Zhao &lt;yuzhao@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
</entry>
</feed>
