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411
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Linus Torvalds
|
40735a683b |
Merge tag 'mm-stable-2026-04-18-02-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton: - "Eliminate Dying Memory Cgroup" (Qi Zheng and Muchun Song) Address the longstanding "dying memcg problem". A situation wherein a no-longer-used memory control group will hang around for an extended period pointlessly consuming memory - "fix unexpected type conversions and potential overflows" (Qi Zheng) Fix a couple of potential 32-bit/64-bit issues which were identified during review of the "Eliminate Dying Memory Cgroup" series - "kho: history: track previous kernel version and kexec boot count" (Breno Leitao) Use Kexec Handover (KHO) to pass the previous kernel's version string and the number of kexec reboots since the last cold boot to the next kernel, and print it at boot time - "liveupdate: prevent double preservation" (Pasha Tatashin) Teach LUO to avoid managing the same file across different active sessions - "liveupdate: Fix module unloading and unregister API" (Pasha Tatashin) Address an issue with how LUO handles module reference counting and unregistration during module unloading - "zswap pool per-CPU acomp_ctx simplifications" (Kanchana Sridhar) Simplify and clean up the zswap crypto compression handling and improve the lifecycle management of zswap pool's per-CPU acomp_ctx resources - "mm/damon/core: fix damon_call()/damos_walk() vs kdmond exit race" (SeongJae Park) Address unlikely but possible leaks and deadlocks in damon_call() and damon_walk() - "mm/damon/core: validate damos_quota_goal->nid" (SeongJae Park) Fix a couple of root-only wild pointer dereferences - "Docs/admin-guide/mm/damon: warn commit_inputs vs other params race" (SeongJae Park) Update the DAMON documentation to warn operators about potential races which can occur if the commit_inputs parameter is altered at the wrong time - "Minor hmm_test fixes and cleanups" (Alistair Popple) Bugfixes and a cleanup for the HMM kernel selftests - "Modify memfd_luo code" (Chenghao Duan) Cleanups, simplifications and speedups to the memfd_lou code - "mm, kvm: allow uffd support in guest_memfd" (Mike Rapoport) Support for userfaultfd in guest_memfd - "selftests/mm: skip several tests when thp is not available" (Chunyu Hu) Fix several issues in the selftests code which were causing breakage when the tests were run on CONFIG_THP=n kernels - "mm/mprotect: micro-optimization work" (Pedro Falcato) A couple of nice speedups for mprotect() - "MAINTAINERS: update KHO and LIVE UPDATE entries" (Pratyush Yadav) Document upcoming changes in the maintenance of KHO, LUO, memfd_luo, kexec, crash, kdump and probably other kexec-based things - they are being moved out of mm.git and into a new git tree * tag 'mm-stable-2026-04-18-02-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (121 commits) MAINTAINERS: add page cache reviewer mm/vmscan: avoid false-positive -Wuninitialized warning MAINTAINERS: update Dave's kdump reviewer email address MAINTAINERS: drop include/linux/liveupdate from LIVE UPDATE MAINTAINERS: drop include/linux/kho/abi/ from KHO MAINTAINERS: update KHO and LIVE UPDATE maintainers MAINTAINERS: update kexec/kdump maintainers entries mm/migrate_device: remove dead migration entry check in migrate_vma_collect_huge_pmd() selftests: mm: skip charge_reserved_hugetlb without killall userfaultfd: allow registration of ranges below mmap_min_addr mm/vmstat: fix vmstat_shepherd double-scheduling vmstat_update mm/hugetlb: fix early boot crash on parameters without '=' separator zram: reject unrecognized type= values in recompress_store() docs: proc: document ProtectionKey in smaps mm/mprotect: special-case small folios when applying permissions mm/mprotect: move softleaf code out of the main function mm: remove '!root_reclaim' checking in should_abort_scan() mm/sparse: fix comment for section map alignment mm/page_io: use sio->len for PSWPIN accounting in sio_read_complete() selftests/mm: transhuge_stress: skip the test when thp not available ... |
||
  Breno LeitaoandAndrew Morton
|
2b19bf0571 |
mm/vmstat: fix vmstat_shepherd double-scheduling vmstat_update
vmstat_shepherd uses delayed_work_pending() to check whether vmstat_update
is already scheduled for a given CPU before queuing it. However,
delayed_work_pending() only tests WORK_STRUCT_PENDING_BIT, which is
cleared the moment a worker thread picks up the work to execute it.
This means that while vmstat_update is actively running on a CPU,
delayed_work_pending() returns false. If need_update() also returns true
at that point (per-cpu counters not yet zeroed mid-flush), the shepherd
queues a second invocation with delay=0, causing vmstat_update to run
again immediately after finishing.
On a 72-CPU system this race is readily observable: before the fix, many
CPUs show invocation gaps well below 500 jiffies (the minimum
round_jiffies_relative() can produce), with the most extreme cases
reaching 0 jiffies—vmstat_update called twice within the same jiffy.
Fix this by replacing delayed_work_pending() with work_busy(), which
returns non-zero for both WORK_BUSY_PENDING (timer armed or work queued)
and WORK_BUSY_RUNNING (work currently executing). The shepherd now
correctly skips a CPU in all busy states.
After the fix, all sub-jiffy and most sub-100-jiffie gaps disappear. The
remaining early invocations have gaps in the 700–999 jiffie range,
attributable to round_jiffies_relative() aligning to a nearer
jiffie-second boundary rather than to this race.
Each spurious vmstat_update invocation has a measurable side effect:
refresh_cpu_vm_stats() calls decay_pcp_high() for every zone, which drains
idle per-CPU pages back to the buddy allocator via free_pcppages_bulk(),
taking the zone spinlock each time. Eliminating the double-scheduling
therefore reduces zone lock contention directly. On a 72-CPU stress-ng
workload measured with perf lock contention:
free_pcppages_bulk contention count: ~55% reduction
free_pcppages_bulk total wait time: ~57% reduction
free_pcppages_bulk max wait time: ~47% reduction
Note: work_busy() is inherently racy—between the check and the
subsequent queue_delayed_work_on() call, vmstat_update can finish
execution, leaving the work neither pending nor running. In that narrow
window the shepherd can still queue a second invocation. After the fix,
this residual race is rare and produces only occasional small gaps, a
significant improvement over the systematic double-scheduling seen with
delayed_work_pending().
Link: https://lore.kernel.org/20260409-vmstat-v2-1-e9d9a6db08ad@debian.org
Fixes:
|
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|
Linus Torvalds
|
334fbe734e |
Merge tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton: - "maple_tree: Replace big node with maple copy" (Liam Howlett) Mainly prepararatory work for ongoing development but it does reduce stack usage and is an improvement. - "mm, swap: swap table phase III: remove swap_map" (Kairui Song) Offers memory savings by removing the static swap_map. It also yields some CPU savings and implements several cleanups. - "mm: memfd_luo: preserve file seals" (Pratyush Yadav) File seal preservation to LUO's memfd code - "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan Chen) Additional userspace stats reportng to zswap - "arch, mm: consolidate empty_zero_page" (Mike Rapoport) Some cleanups for our handling of ZERO_PAGE() and zero_pfn - "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu Han) A robustness improvement and some cleanups in the kmemleak code - "Improve khugepaged scan logic" (Vernon Yang) Improve khugepaged scan logic and reduce CPU consumption by prioritizing scanning tasks that access memory frequently - "Make KHO Stateless" (Jason Miu) Simplify Kexec Handover by transitioning KHO from an xarray-based metadata tracking system with serialization to a radix tree data structure that can be passed directly to the next kernel - "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas Ballasi and Steven Rostedt) Enhance vmscan's tracepointing - "mm: arch/shstk: Common shadow stack mapping helper and VM_NOHUGEPAGE" (Catalin Marinas) Cleanup for the shadow stack code: remove per-arch code in favour of a generic implementation - "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin) Fix a WARN() which can be emitted the KHO restores a vmalloc area - "mm: Remove stray references to pagevec" (Tal Zussman) Several cleanups, mainly udpating references to "struct pagevec", which became folio_batch three years ago - "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl Shutsemau) Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail pages encode their relationship to the head page - "mm/damon/core: improve DAMOS quota efficiency for core layer filters" (SeongJae Park) Improve two problematic behaviors of DAMOS that makes it less efficient when core layer filters are used - "mm/damon: strictly respect min_nr_regions" (SeongJae Park) Improve DAMON usability by extending the treatment of the min_nr_regions user-settable parameter - "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka) The proper fix for a previously hotfixed SMP=n issue. Code simplifications and cleanups ensued - "mm: cleanups around unmapping / zapping" (David Hildenbrand) A bunch of cleanups around unmapping and zapping. Mostly simplifications, code movements, documentation and renaming of zapping functions - "support batched checking of the young flag for MGLRU" (Baolin Wang) Batched checking of the young flag for MGLRU. It's part cleanups; one benchmark shows large performance benefits for arm64 - "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner) memcg cleanup and robustness improvements - "Allow order zero pages in page reporting" (Yuvraj Sakshith) Enhance free page reporting - it is presently and undesirably order-0 pages when reporting free memory. - "mm: vma flag tweaks" (Lorenzo Stoakes) Cleanup work following from the recent conversion of the VMA flags to a bitmap - "mm/damon: add optional debugging-purpose sanity checks" (SeongJae Park) Add some more developer-facing debug checks into DAMON core - "mm/damon: test and document power-of-2 min_region_sz requirement" (SeongJae Park) An additional DAMON kunit test and makes some adjustments to the addr_unit parameter handling - "mm/damon/core: make passed_sample_intervals comparisons overflow-safe" (SeongJae Park) Fix a hard-to-hit time overflow issue in DAMON core - "mm/damon: improve/fixup/update ratio calculation, test and documentation" (SeongJae Park) A batch of misc/minor improvements and fixups for DAMON - "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David Hildenbrand) Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code movement was required. - "zram: recompression cleanups and tweaks" (Sergey Senozhatsky) A somewhat random mix of fixups, recompression cleanups and improvements in the zram code - "mm/damon: support multiple goal-based quota tuning algorithms" (SeongJae Park) Extend DAMOS quotas goal auto-tuning to support multiple tuning algorithms that users can select - "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao) Fix the khugpaged sysfs handling so we no longer spam the logs with reams of junk when starting/stopping khugepaged - "mm: improve map count checks" (Lorenzo Stoakes) Provide some cleanups and slight fixes in the mremap, mmap and vma code - "mm/damon: support addr_unit on default monitoring targets for modules" (SeongJae Park) Extend the use of DAMON core's addr_unit tunable - "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache) Cleanups to khugepaged and is a base for Nico's planned khugepaged mTHP support - "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand) Code movement and cleanups in the memhotplug and sparsemem code - "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup CONFIG_MIGRATION" (David Hildenbrand) Rationalize some memhotplug Kconfig support - "change young flag check functions to return bool" (Baolin Wang) Cleanups to change all young flag check functions to return bool - "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh Law and SeongJae Park) Fix a few potential DAMON bugs - "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo Stoakes) Convert a lot of the existing use of the legacy vm_flags_t data type to the new vma_flags_t type which replaces it. Mainly in the vma code. - "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes) Expand the mmap_prepare functionality, which is intended to replace the deprecated f_op->mmap hook which has been the source of bugs and security issues for some time. Cleanups, documentation, extension of mmap_prepare into filesystem drivers - "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes) Simplify and clean up zap_huge_pmd(). Additional cleanups around vm_normal_folio_pmd() and the softleaf functionality are performed. * tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm: fix deferred split queue races during migration mm/khugepaged: fix issue with tracking lock mm/huge_memory: add and use has_deposited_pgtable() mm/huge_memory: add and use normal_or_softleaf_folio_pmd() mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio() mm/huge_memory: separate out the folio part of zap_huge_pmd() mm/huge_memory: use mm instead of tlb->mm mm/huge_memory: remove unnecessary sanity checks mm/huge_memory: deduplicate zap deposited table call mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE() mm/huge_memory: add a common exit path to zap_huge_pmd() mm/huge_memory: handle buggy PMD entry in zap_huge_pmd() mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc mm/huge: avoid big else branch in zap_huge_pmd() mm/huge_memory: simplify vma_is_specal_huge() mm: on remap assert that input range within the proposed VMA mm: add mmap_action_map_kernel_pages[_full]() uio: replace deprecated mmap hook with mmap_prepare in uio_info drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare mm: allow handling of stacked mmap_prepare hooks in more drivers ... |
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 Dave Airlie
|
2232ba9c79 |
mm: add gpu active/reclaim per-node stat counters (v2)
While discussing memcg intergration with gpu memory allocations, it was pointed out that there was no numa/system counters for GPU memory allocations. With more integrated memory GPU server systems turning up, and more requirements for memory tracking it seems we should start closing the gap. Add two counters to track GPU per-node system memory allocations. The first is currently allocated to GPU objects, and the second is for memory that is stored in GPU page pools that can be reclaimed, by the shrinker. Cc: Christian Koenig <christian.koenig@amd.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: linux-mm@kvack.org Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Zi Yan <ziy@nvidia.com> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Christian König <christian.koenig@amd.com> Signed-off-by: Dave Airlie <airlied@redhat.com> |
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 Johannes WeinerandAndrew Morton
|
b9ec0ed907 |
mm: vmalloc: streamline vmalloc memory accounting
Use a vmstat counter instead of a custom, open-coded atomic. This has the added benefit of making the data available per-node, and prepares for cleaning up the memcg accounting as well. Link: https://lkml.kernel.org/r/20260223160147.3792777-1-hannes@cmpxchg.org Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Miquel Sabaté SolàandAndrew Morton
|
e623b4ebee |
mm: fix typo in the comment of mod_zone_state()
Use the proper function name, followed by parenthesis as usual. Link: https://lkml.kernel.org/r/20260219234407.3261196-1-mssola@mssola.com Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com> Acked-by: SeongJae Park <sj@kernel.org> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 JP Kobryn (Meta)andAndrew Morton
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e4f4fc7aa8 |
mm: move pgscan, pgsteal, pgrefill to node stats
There are situations where reclaim kicks in on a system with free memory. One possible cause is a NUMA imbalance scenario where one or more nodes are under pressure. It would help if we could easily identify such nodes. Move the pgscan, pgsteal, and pgrefill counters from vm_event_item to node_stat_item to provide per-node reclaim visibility. With these counters as node stats, the values are now displayed in the per-node section of /proc/zoneinfo, which allows for quick identification of the affected nodes. /proc/vmstat continues to report the same counters, aggregated across all nodes. But the ordering of these items within the readout changes as they move from the vm events section to the node stats section. Memcg accounting of these counters is preserved. The relocated counters remain visible in memory.stat alongside the existing aggregate pgscan and pgsteal counters. However, this change affects how the global counters are accumulated. Previously, the global event count update was gated on !cgroup_reclaim(), excluding memcg-based reclaim from /proc/vmstat. Now that mod_lruvec_state() is being used to update the counters, the global counters will include all reclaim. This is consistent with how pgdemote counters are already tracked. Finally, the virtio_balloon driver is updated to use global_node_page_state() to fetch the counters, as they are no longer accessible through the vm_events array. Link: https://lkml.kernel.org/r/20260219235846.161910-1-jp.kobryn@linux.dev Signed-off-by: JP Kobryn <jp.kobryn@linux.dev> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: David Hildenbrand <david@kernel.org> Cc: Eugenio Pérez <eperezma@redhat.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mathew Brost <matthew.brost@intel.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Cc: Yuanchu Xie <yuanchu@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Linus Torvalds
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4cff5c05e0 |
Merge tag 'mm-stable-2026-02-11-19-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- "powerpc/64s: do not re-activate batched TLB flush" makes
arch_{enter|leave}_lazy_mmu_mode() nest properly (Alexander Gordeev)
It adds a generic enter/leave layer and switches architectures to use
it. Various hacks were removed in the process.
- "zram: introduce compressed data writeback" implements data
compression for zram writeback (Richard Chang and Sergey Senozhatsky)
- "mm: folio_zero_user: clear page ranges" adds clearing of contiguous
page ranges for hugepages. Large improvements during demand faulting
are demonstrated (David Hildenbrand)
- "memcg cleanups" tidies up some memcg code (Chen Ridong)
- "mm/damon: introduce {,max_}nr_snapshots and tracepoint for damos
stats" improves DAMOS stat's provided information, deterministic
control, and readability (SeongJae Park)
- "selftests/mm: hugetlb cgroup charging: robustness fixes" fixes a few
issues in the hugetlb cgroup charging selftests (Li Wang)
- "Fix va_high_addr_switch.sh test failure - again" addresses several
issues in the va_high_addr_switch test (Chunyu Hu)
- "mm/damon/tests/core-kunit: extend existing test scenarios" improves
the KUnit test coverage for DAMON (Shu Anzai)
- "mm/khugepaged: fix dirty page handling for MADV_COLLAPSE" fixes a
glitch in khugepaged which was causing madvise(MADV_COLLAPSE) to
transiently return -EAGAIN (Shivank Garg)
- "arch, mm: consolidate hugetlb early reservation" reworks and
consolidates a pile of straggly code related to reservation of
hugetlb memory from bootmem and creation of CMA areas for hugetlb
(Mike Rapoport)
- "mm: clean up anon_vma implementation" cleans up the anon_vma
implementation in various ways (Lorenzo Stoakes)
- "tweaks for __alloc_pages_slowpath()" does a little streamlining of
the page allocator's slowpath code (Vlastimil Babka)
- "memcg: separate private and public ID namespaces" cleans up the
memcg ID code and prevents the internal-only private IDs from being
exposed to userspace (Shakeel Butt)
- "mm: hugetlb: allocate frozen gigantic folio" cleans up the
allocation of frozen folios and avoids some atomic refcount
operations (Kefeng Wang)
- "mm/damon: advance DAMOS-based LRU sorting" improves DAMOS's movement
of memory betewwn the active and inactive LRUs and adds auto-tuning
of the ratio-based quotas and of monitoring intervals (SeongJae Park)
- "Support page table check on PowerPC" makes
CONFIG_PAGE_TABLE_CHECK_ENFORCED work on powerpc (Andrew Donnellan)
- "nodemask: align nodes_and{,not} with underlying bitmap ops" makes
nodes_and() and nodes_andnot() propagate the return values from the
underlying bit operations, enabling some cleanup in calling code
(Yury Norov)
- "mm/damon: hide kdamond and kdamond_lock from API callers" cleans up
some DAMON internal interfaces (SeongJae Park)
- "mm/khugepaged: cleanups and scan limit fix" does some cleanup work
in khupaged and fixes a scan limit accounting issue (Shivank Garg)
- "mm: balloon infrastructure cleanups" goes to town on the balloon
infrastructure and its page migration function. Mainly cleanups, also
some locking simplification (David Hildenbrand)
- "mm/vmscan: add tracepoint and reason for kswapd_failures reset" adds
additional tracepoints to the page reclaim code (Jiayuan Chen)
- "Replace wq users and add WQ_PERCPU to alloc_workqueue() users" is
part of Marco's kernel-wide migration from the legacy workqueue APIs
over to the preferred unbound workqueues (Marco Crivellari)
- "Various mm kselftests improvements/fixes" provides various unrelated
improvements/fixes for the mm kselftests (Kevin Brodsky)
- "mm: accelerate gigantic folio allocation" greatly speeds up gigantic
folio allocation, mainly by avoiding unnecessary work in
pfn_range_valid_contig() (Kefeng Wang)
- "selftests/damon: improve leak detection and wss estimation
reliability" improves the reliability of two of the DAMON selftests
(SeongJae Park)
- "mm/damon: cleanup kdamond, damon_call(), damos filter and
DAMON_MIN_REGION" does some cleanup work in the core DAMON code
(SeongJae Park)
- "Docs/mm/damon: update intro, modules, maintainer profile, and misc"
performs maintenance work on the DAMON documentation (SeongJae Park)
- "mm: add and use vma_assert_stabilised() helper" refactors and cleans
up the core VMA code. The main aim here is to be able to use the mmap
write lock's lockdep state to perform various assertions regarding
the locking which the VMA code requires (Lorenzo Stoakes)
- "mm, swap: swap table phase II: unify swapin use" removes some old
swap code (swap cache bypassing and swap synchronization) which
wasn't working very well. Various other cleanups and simplifications
were made. The end result is a 20% speedup in one benchmark (Kairui
Song)
- "enable PT_RECLAIM on more 64-bit architectures" makes PT_RECLAIM
available on 64-bit alpha, loongarch, mips, parisc, and um. Various
cleanups were performed along the way (Qi Zheng)
* tag 'mm-stable-2026-02-11-19-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (325 commits)
mm/memory: handle non-split locks correctly in zap_empty_pte_table()
mm: move pte table reclaim code to memory.c
mm: make PT_RECLAIM depends on MMU_GATHER_RCU_TABLE_FREE
mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config
um: mm: enable MMU_GATHER_RCU_TABLE_FREE
parisc: mm: enable MMU_GATHER_RCU_TABLE_FREE
mips: mm: enable MMU_GATHER_RCU_TABLE_FREE
LoongArch: mm: enable MMU_GATHER_RCU_TABLE_FREE
alpha: mm: enable MMU_GATHER_RCU_TABLE_FREE
mm: change mm/pt_reclaim.c to use asm/tlb.h instead of asm-generic/tlb.h
mm/damon/stat: remove __read_mostly from memory_idle_ms_percentiles
zsmalloc: make common caches global
mm: add SPDX id lines to some mm source files
mm/zswap: use %pe to print error pointers
mm/vmscan: use %pe to print error pointers
mm/readahead: fix typo in comment
mm: khugepaged: fix NR_FILE_PAGES and NR_SHMEM in collapse_file()
mm: refactor vma_map_pages to use vm_insert_pages
mm/damon: unify address range representation with damon_addr_range
mm/cma: replace snprintf with strscpy in cma_new_area
...
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 Frederic Weisbecker
|
ce84ad5e99 |
sched/isolation: Flush vmstat workqueues on cpuset isolated partition change
The HK_TYPE_DOMAIN housekeeping cpumask is now modifiable at runtime. In order to synchronize against vmstat workqueue to make sure that no asynchronous vmstat work is still pending or executing on a newly made isolated CPU, the housekeeping susbsystem must flush the vmstat workqueues. This involves flushing the whole mm_percpu_wq workqueue, shared with LRU drain, introducing here a welcome side effect. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Marco Crivellari <marco.crivellari@suse.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Waiman Long <longman@redhat.com> Cc: linux-mm@kvack.org |
||
|
Frederic Weisbecker
|
69e227e450 |
mm: vmstat: Prepare to protect against concurrent isolated cpuset change
The HK_TYPE_DOMAIN housekeeping cpumask will soon be made modifiable at runtime. In order to synchronize against vmstat workqueue to make sure that no asynchronous vmstat work is pending or executing on a newly made isolated CPU, target and queue a vmstat work under the same RCU read side critical section. Whenever housekeeping will update the HK_TYPE_DOMAIN cpumask, a vmstat workqueue flush will also be issued in a further change to make sure that no work remains pending after a CPU has been made isolated. Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Crivellari <marco.crivellari@suse.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Waiman Long <longman@redhat.com> Cc: linux-mm@kvack.org |
||
 Marco CrivellariandAndrew Morton
|
ed0a826ce3 |
mm: add WQ_PERCPU to alloc_workqueue users
This continues the effort to refactor workqueue APIs, which began with the introduction of new workqueues and a new alloc_workqueue flag in: commit |
||
 Jiayuan ChenandAndrew Morton
|
a45088376d |
mm/vmscan: add tracepoint and reason for kswapd_failures reset
Currently, kswapd_failures is reset in multiple places (kswapd, direct reclaim, PCP freeing, memory-tiers), but there's no way to trace when and why it was reset, making it difficult to debug memory reclaim issues. This patch: 1. Introduce kswapd_clear_hopeless() as a wrapper function to centralize kswapd_failures reset logic. 2. Introduce kswapd_test_hopeless() to encapsulate hopeless node checks, replacing all open-coded kswapd_failures comparisons. 3. Add kswapd_clear_hopeless_reason enum to distinguish reset sources: - KSWAPD_CLEAR_HOPELESS_KSWAPD: reset from kswapd context - KSWAPD_CLEAR_HOPELESS_DIRECT: reset from direct reclaim - KSWAPD_CLEAR_HOPELESS_PCP: reset from PCP page freeing - KSWAPD_CLEAR_HOPELESS_OTHER: reset from other paths 4. Add tracepoints for better observability: - mm_vmscan_kswapd_clear_hopeless: traces each reset with reason - mm_vmscan_kswapd_reclaim_fail: traces each kswapd reclaim failure Test results: $ trace-cmd record -e vmscan:mm_vmscan_kswapd_clear_hopeless -e vmscan:mm_vmscan_kswapd_reclaim_fail $ # generate memory pressure $ trace-cmd report cpus=4 kswapd0-71 [000] 27.216563: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=1 kswapd0-71 [000] 27.217169: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=2 kswapd0-71 [000] 27.217764: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=3 kswapd0-71 [000] 27.218353: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=4 kswapd0-71 [000] 27.218993: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=5 kswapd0-71 [000] 27.219744: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=6 kswapd0-71 [000] 27.220488: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=7 kswapd0-71 [000] 27.221206: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=8 kswapd0-71 [000] 27.221806: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=9 kswapd0-71 [000] 27.222634: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=10 kswapd0-71 [000] 27.223286: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=11 kswapd0-71 [000] 27.223894: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=12 kswapd0-71 [000] 27.224712: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=13 kswapd0-71 [000] 27.225424: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=14 kswapd0-71 [000] 27.226082: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=15 kswapd0-71 [000] 27.226810: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=16 kswapd1-72 [002] 27.386869: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=1 kswapd1-72 [002] 27.387435: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=2 kswapd1-72 [002] 27.388016: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=3 kswapd1-72 [002] 27.388586: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=4 kswapd1-72 [002] 27.389155: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=5 kswapd1-72 [002] 27.389723: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=6 kswapd1-72 [002] 27.390292: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=7 kswapd1-72 [002] 27.392364: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=8 kswapd1-72 [002] 27.392934: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=9 kswapd1-72 [002] 27.393504: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=10 kswapd1-72 [002] 27.394073: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=11 kswapd1-72 [002] 27.394899: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=12 kswapd1-72 [002] 27.395472: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=13 kswapd1-72 [002] 27.396055: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=14 kswapd1-72 [002] 27.396628: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=15 kswapd1-72 [002] 27.397199: mm_vmscan_kswapd_reclaim_fail: nid=1 failures=16 kworker/u18:0-40 [002] 27.410151: mm_vmscan_kswapd_clear_hopeless: nid=0 reason=DIRECT kswapd0-71 [000] 27.439454: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=1 kswapd0-71 [000] 27.440048: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=2 kswapd0-71 [000] 27.440634: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=3 kswapd0-71 [000] 27.441211: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=4 kswapd0-71 [000] 27.441787: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=5 kswapd0-71 [000] 27.442363: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=6 kswapd0-71 [000] 27.443030: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=7 kswapd0-71 [000] 27.443725: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=8 kswapd0-71 [000] 27.444315: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=9 kswapd0-71 [000] 27.444898: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=10 kswapd0-71 [000] 27.445476: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=11 kswapd0-71 [000] 27.446053: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=12 kswapd0-71 [000] 27.446646: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=13 kswapd0-71 [000] 27.447230: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=14 kswapd0-71 [000] 27.447812: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=15 kswapd0-71 [000] 27.448391: mm_vmscan_kswapd_reclaim_fail: nid=0 failures=16 ann-423 [003] 28.028285: mm_vmscan_kswapd_clear_hopeless: nid=0 reason=PCP Link: https://lkml.kernel.org/r/20260120024402.387576-3-jiayuan.chen@linux.dev Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> [tracing] Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: David Hildenbrand <david@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
 David Hildenbrand (Red Hat)andAndrew Morton
|
1421758055 |
mm: rename CONFIG_MEMORY_BALLOON -> CONFIG_BALLOON
Let's make it consistent with the naming of the files but also with the naming of CONFIG_BALLOON_MIGRATION. While at it, add a "/* CONFIG_BALLOON */". Link: https://lkml.kernel.org/r/20260119230133.3551867-24-david@kernel.org Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Eugenio Pérez <eperezma@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jason Wang <jasowang@redhat.com> Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: SeongJae Park <sj@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
David Hildenbrand (Red Hat)andAndrew Morton
|
cd8e95d80b |
mm: rename CONFIG_BALLOON_COMPACTION to CONFIG_BALLOON_MIGRATION
While compaction depends on migration, the other direction is not the case. So let's make it clearer that this is all about migration of balloon pages. Adjust all comments/docs in the core to talk about "migration" instead of "compaction". While at it add some "/* CONFIG_BALLOON_MIGRATION */". Link: https://lkml.kernel.org/r/20260119230133.3551867-23-david@kernel.org Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Eugenio Pérez <eperezma@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jason Wang <jasowang@redhat.com> Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: SeongJae Park <sj@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
 Wei YangandAndrew Morton
|
a8d933dc33 |
mm/vmstat: remove unused node and zone state helpers
Several helper functions for managing node and zone states have become obsolete and no longer have any callers within the kernel. inc_node_state() inc_zone_state() dec_zone_state() This commit removes the dead code. Link: https://lkml.kernel.org/r/20251225210213.2553-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Kevin LourencoandAndrew Morton
|
62451ae347 |
mm: fix minor spelling mistakes in comments
Correct several typos in comments across files in mm/ [akpm@linux-foundation.org: also fix comment grammar, per SeongJae] Link: https://lkml.kernel.org/r/20251218150906.25042-1-klourencodev@gmail.com Signed-off-by: Kevin Lourenco <klourencodev@gmail.com> Reviewed-by: SeongJae Park <sj@kernel.org> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Qi ZhengandAndrew Morton
|
3a47e8771c |
mm: vmstat: correct the comment above preempt_disable_nested()
The comment explaining why these parts use preempt_disable_nested() is in __mod_zone_page_state(), not in __mod_node_page_state(), so we should see __mod_zone_page_state(). Just correct it. Link: https://lkml.kernel.org/r/20251110084437.46701-1-qi.zheng@linux.dev Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Harry Yoo <harry.yoo@oracle.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Jiayuan ChenandAndrew Morton
|
6af766c86b |
mm: vmstat: output reserved_highatomic and free_highatomic in zoneinfo
The nr_free_highatomic is a key factor in calculating watermarks as it affects the free pages count. Adding this metric, along with nr_reserved_highatomic, to /proc/zoneinfo facilitates easier diagnosis memory watermark calculations and memory pressure states. Sample output: cat /proc/zoneinfo ...... pagesets cpu: 0 count: 52069 high: 52675 batch: 63 high_min: 13971 high_max: 62284 vm stats threshold: 10 node_unreclaimable: 0 start_pfn: 4096 reserved_highatomic: 5120 free_highatomic: 2081 Link: https://lkml.kernel.org/r/20251027141818.283587-1-jiayuan.chen@linux.dev Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Cc: David Hildenbrand <david@redhat.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Jing SuandAndrew Morton
|
645a3c4243 |
mm/vmstat: fix indentation in fold_diff function
Adjust misaligned braces in fold_diff() to improve code readability and maintain consistent coding style. [akpm@linux-foundation.org: add braces, per Vlastimil & Liam] Link: https://lkml.kernel.org/r/aPc4I/8zXCGyiapN@pilot-ThinkCentre-M930t-N000 Signed-off-by: Jing Su <jingsusu@didiglobal.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Donet Tom <donettom@linux.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Dev Jain <dev.jain@arm.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Joshua HahnandAndrew Morton
|
0acc67c403 |
mm/page_alloc/vmstat: simplify refresh_cpu_vm_stats change detection
Patch series "mm/page_alloc: Batch callers of free_pcppages_bulk", v5. Motivation & Approach ===================== While testing workloads with high sustained memory pressure on large machines in the Meta fleet (1Tb memory, 316 CPUs), we saw an unexpectedly high number of softlockups. Further investigation showed that the zone lock in free_pcppages_bulk was being held for a long time, and was called to free 2k+ pages over 100 times just during boot. This causes starvation in other processes for the zone lock, which can lead to the system stalling as multiple threads cannot make progress without the locks. We can see these issues manifesting as warnings: [ 4512.591979] rcu: INFO: rcu_sched self-detected stall on CPU [ 4512.604370] rcu: 20-....: (9312 ticks this GP) idle=a654/1/0x4000000000000000 softirq=309340/309344 fqs=5426 [ 4512.626401] rcu: hardirqs softirqs csw/system [ 4512.638793] rcu: number: 0 145 0 [ 4512.651177] rcu: cputime: 30 10410 174 ==> 10558(ms) [ 4512.666657] rcu: (t=21077 jiffies g=783665 q=1242213 ncpus=316) While these warnings don't indicate a crash or a kernel panic, they do point to the underlying issue of lock contention. To prevent starvation in both locks, batch the freeing of pages using pcp->batch. Because free_pcppages_bulk is called with the pcp lock and acquires the zone lock, relinquishing and reacquiring the locks are only effective when both of them are broken together (unless the system was built with queued spinlocks). Thus, instead of modifying free_pcppages_bulk to break both locks, batch the freeing from its callers instead. A similar fix has been implemented in the Meta fleet, and we have seen significantly less softlockups. Testing ======= The following are a few synthetic benchmarks, made on three machines. The first is a large machine with 754GiB memory and 316 processors. The second is a relatively smaller machine with 251GiB memory and 176 processors. The third and final is the smallest of the three, which has 62GiB memory and 36 processors. On all machines, I kick off a kernel build with -j$(nproc). Negative delta is better (faster compilation). Large machine (754GiB memory, 316 processors) make -j$(nproc) +------------+---------------+-----------+ | Metric (s) | Variation (%) | Delta(%) | +------------+---------------+-----------+ | real | 0.8070 | - 1.4865 | | user | 0.2823 | + 0.4081 | | sys | 5.0267 | -11.8737 | +------------+---------------+-----------+ Medium machine (251GiB memory, 176 processors) make -j$(nproc) +------------+---------------+----------+ | Metric (s) | Variation (%) | Delta(%) | +------------+---------------+----------+ | real | 0.2806 | +0.0351 | | user | 0.0994 | +0.3170 | | sys | 0.6229 | -0.6277 | +------------+---------------+----------+ Small machine (62GiB memory, 36 processors) make -j$(nproc) +------------+---------------+----------+ | Metric (s) | Variation (%) | Delta(%) | +------------+---------------+----------+ | real | 0.1503 | -2.6585 | | user | 0.0431 | -2.2984 | | sys | 0.1870 | -3.2013 | +------------+---------------+----------+ Here, variation is the coefficient of variation, i.e. standard deviation / mean. Based on these results, it seems like there are varying degrees to how much lock contention this reduces. For the largest and smallest machines that I ran the tests on, it seems like there is quite some significant reduction. There is also some performance increases visible from userspace. Interestingly, the performance gains don't scale with the size of the machine, but rather there seems to be a dip in the gain there is for the medium-sized machine. One possible theory is that because the high watermark depends on both memory and the number of local CPUs, what impacts zone contention the most is not these individual values, but rather the ratio of mem:processors. This patch (of 5): Currently, refresh_cpu_vm_stats returns an int, indicating how many changes were made during its updates. Using this information, callers like vmstat_update can heuristically determine if more work will be done in the future. However, all of refresh_cpu_vm_stats's callers either (a) ignore the result, only caring about performing the updates, or (b) only care about whether changes were made, but not *how many* changes were made. Simplify the code by returning a bool instead to indicate if updates were made. In addition, simplify fold_diff and decay_pcp_high to return a bool for the same reason. Link: https://lkml.kernel.org/r/20251014145011.3427205-1-joshua.hahnjy@gmail.com Link: https://lkml.kernel.org/r/20251014145011.3427205-2-joshua.hahnjy@gmail.com Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Chris Mason <clm@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Michal Hocko <mhocko@suse.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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 Chanwon ParkandAndrew Morton
|
e7a5f249e6 |
mm: re-enable kswapd when memory pressure subsides or demotion is toggled
If kswapd fails to reclaim pages from a node MAX_RECLAIM_RETRIES in a
row, kswapd on that node gets disabled. That is, the system won't wakeup
kswapd for that node until page reclamation is observed at least once.
That reclamation is mostly done by direct reclaim, which in turn enables
kswapd back.
However, on systems with CXL memory nodes, workloads with high anon page
usage can disable kswapd indefinitely, without triggering direct
reclaim. This can be reproduced with following steps:
numa node 0 (32GB memory, 48 CPUs)
numa node 2~5 (512GB CXL memory, 128GB each)
(numa node 1 is disabled)
swap space 8GB
1) Set /sys/kernel/mm/demotion_enabled to 0.
2) Set /proc/sys/kernel/numa_balancing to 0.
3) Run a process that allocates and random accesses 500GB of anon
pages.
4) Let the process exit normally.
During 3), free memory on node 0 gets lower than low watermark, and
kswapd runs and depletes swap space. Then, kswapd fails consecutively
and gets disabled. Allocation afterwards happens on CXL memory, so node
0 never gains more memory pressure to trigger direct reclaim.
After 4), kswapd on node 0 remains disabled, and tasks running on that
node are unable to swap. If you turn on NUMA_BALANCING_MEMORY_TIERING
and demotion now, it won't work properly since kswapd is disabled.
To mitigate this problem, reset kswapd_failures to 0 on following
conditions:
a) ZONE_BELOW_HIGH bit of a zone in hopeless node with a fallback
memory node gets cleared.
b) demotion_enabled is changed from false to true.
Rationale for a):
ZONE_BELOW_HIGH bit being cleared might be a sign that the node may
be reclaimable afterwards. This won't help much if the memory-hungry
process keeps running without freeing anything, but at least the node
will go back to reclaimable state when the process exits.
Rationale for b):
When demotion_enabled is false, kswapd can only reclaim anon pages by
swapping them out to swap space. If demotion_enabled is turned on,
kswapd can demote anon pages to another node for reclaiming. So, the
original failure count for determining reclaimability is no longer
valid.
Since kswapd_failures resets may be missed by ++ operation, it is
changed from int to atomic_t.
[akpm@linux-foundation.org: tweak whitespace]
Link: https://lkml.kernel.org/r/aL6qGi69jWXfPc4D@pcw-MS-7D22
Signed-off-by: Chanwon Park <flyinrm@gmail.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
 Boris BurkovandAndrew Morton
|
e3a9ac4e86 |
mm: add vmstat for kernel_file pages
Kernel file pages are tricky to track because they are indistinguishable from files whose usage is accounted to the root cgroup. To maintain good accounting, introduce a vmstat counter tracking kernel file pages. Confirmed that these work as expected at a high level by mounting a btrfs using AS_KERNEL_FILE for metadata pages, and seeing the counter rise with fs usage then go back to a minimal level after drop_caches and finally down to 0 after unmounting the fs. Link: https://lkml.kernel.org/r/08ff633e3a005ed5f7691bfd9f58a5df8e474339.1755812945.git.boris@bur.io Signed-off-by: Boris Burkov <boris@bur.io> Suggested-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Tested-by: syzbot@syzkaller.appspotmail.com Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qu Wenruo <wqu@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
 Ruan ShiyangandAndrew Morton
|
337135e612 |
mm: memory-tiering: fix PGPROMOTE_CANDIDATE counting
Goto-san reported confusing pgpromote statistics where the
pgpromote_success count significantly exceeded pgpromote_candidate.
On a system with three nodes (nodes 0-1: DRAM 4GB, node 2: NVDIMM 4GB):
# Enable demotion only
echo 1 > /sys/kernel/mm/numa/demotion_enabled
numactl -m 0-1 memhog -r200 3500M >/dev/null &
pid=$!
sleep 2
numactl memhog -r100 2500M >/dev/null &
sleep 10
kill -9 $pid # terminate the 1st memhog
# Enable promotion
echo 2 > /proc/sys/kernel/numa_balancing
After a few seconds, we observeed `pgpromote_candidate < pgpromote_success`
$ grep -e pgpromote /proc/vmstat
pgpromote_success 2579
pgpromote_candidate 0
In this scenario, after terminating the first memhog, the conditions for
pgdat_free_space_enough() are quickly met, and triggers promotion.
However, these migrated pages are only counted for in PGPROMOTE_SUCCESS,
not in PGPROMOTE_CANDIDATE.
To solve these confusing statistics, introduce PGPROMOTE_CANDIDATE_NRL to
count the missed promotion pages. And also, not counting these pages into
PGPROMOTE_CANDIDATE is to avoid changing the existing algorithm or
performance of the promotion rate limit.
Link: https://lkml.kernel.org/r/20250901090122.124262-1-ruansy.fnst@fujitsu.com
Link: https://lkml.kernel.org/r/20250729035101.1601407-1-ruansy.fnst@fujitsu.com
Fixes:
|
||
 Vlastimil BabkaandAndrew Morton
|
8356a5a3b0 |
mm, vmstat: remove the NR_WRITEBACK_TEMP node_stat_item counter
The only user of the counter (FUSE) was removed in commit
|
||
 Kirill A. ShutemovandAndrew Morton
|
ed6a9068a0 |
mm/vmstat: utilize designated initializers for the vmstat_text array
The vmstat_text array defines labels for counters displayed in /proc/vmstat. The current definition of the array implies a specific order of the counters in their enums, making it fragile. To make it clear which counter the label is for, use designated initializers. Link: https://lkml.kernel.org/r/20250603084556.113975-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |