linux/Documentation/mm
Linus Torvalds 8a36f53fd5 mm.git review status for linus..mm-stable
Everything:
 
 Total patches:       213
 Fixes: tags:         69
 cc:stable patches:   43
 Reviews/patch:       2.04
 Reviewed rate:       86%
 
 Excluding DAMON:
 
 Total patches:       192
 Fixes: tags:         63
 cc:stable patches:   39
 Reviews/patch:       2.18
 Reviewed rate:       89%
 
 Excluding DAMON and selftests:
 
 Total patches:       182
 Fixes: tags:         57
 cc:stable patches:   39
 Reviews/patch:       2.23
 Reviewed rate:       89%
 
 Summary of series in this merge:
 
 - "mm: make VMA flag semantics explicit, eliminate VM_SPECIAL"
   (Lorenzo Stoakes (ARM)):
 
   Replace VM_SPECIAL with helpers describing mapping ownership and
   behavior.  Enforce the mmap flag rules and convert affected drivers,
   removing ambiguous tests shared by driver mappings and ordinary memory.
 
 - "support kselftest on nommu platform" (Hajime Tazaki):
 
   Add opt-in mmap and mremap tests for NOMMU systems.  Teach the runner to
   avoid its fork-dependent timeout command and document the build and
   runtime requirements.
 
 - "mm/collapse: separate a collapse from its callers"
   (Kiryl Shutsemau (Meta)):
 
   Separate huge-page collapse from caller policy.  Replace khugepaged
   identity checks with explicit permissions, and separate scanning from
   collapse with the mmap_lock drop in one place.
 
 - "mm: implement and use vma_has_anon_rmap(), silence KCSAN"
   (Lorenzo Stoakes (ARM)):
 
   Provide a common helper for testing whether a VMA has anonymous reverse
   mappings.  Document the locking rules, annotate intentional concurrent
   reads for KCSAN, and convert the core MM callers.
 
 - "mm/sparse: remove SECTION_MARKED_PRESENT and further cleanups"
   (David Hildenbrand (Arm)):
 
   Remove SECTION_MARKED_PRESENT in favor of the early-section flag.
   Simplify sparse memory initialization, section metadata handling and
   related PFN validity checks.
 
 - "sh: remove NUMA and SPARSEMEM support" (Mike Rapoport (Microsoft)):
 
   Remove SuperH NUMA and SPARSEMEM support.  The extra memory banks have
   been unusable since the NO_BOOTMEM conversion, leaving only the code and
   data overhead.
 
 - "mm: Unify device DAX and HugeTLB vmemmap population paths"
   (Muchun Song):
 
   Unify the generic device DAX and HugeTLB vmemmap population paths and
   shared tail-page handling.  Remove the duplicate DAX machinery while
   retaining the powerpc radix implementation.
 
 - "kselftest: mm: fix some failure of split_huge_page_test" (Yeoreum Yun):
 
   Fix huge-page split tests racing with khugepaged recollapse.  Use pagemap
   and page flags instead of VMA-boundary assumptions which fail when glibc
   has already enabled THP.
 
 - "memcg: move memcgid refcount to objcg to unpin dying memcgs"
   (Bingfang Guo):
 
   Let dying memcgs be freed while swapped-out shmem still holds their IDs.
   Move ID references to reparentable objcgs, with the necessary swap
   accounting and RCU lifetime changes.
 
 - "mm/truncate: fix data loss when truncating straddling large folios"
   (Zhang Yi):
 
   Preserve out-of-range data when truncating straddling large folios.  Fix
   a lookup race and split-failure handling, and handle minimum folio orders
   for the forthcoming ext4 iomap buffered I/O path.
 
 - "mm/damon: introduce damos quota goal target metric complement flag"
   (SJ Park):
 
   Let DAMOS quota goals use a metric's complement, so utilization can also
   express free-memory goals without adding separate metrics.  Add the sysfs
   interface, documentation and tests.
 
 - "arm64/mm: Standardize printing for pgtable entries" (Anshuman Khandual):
 
   Use the generic formatter for arm64 page-table entries, ready for future
   wider entries.  Move the safe-PTE-update check out of the header to avoid
   an include cycle.
 
 - "mm: kmsan: fix iounmap metadata teardown" (Dima Koziuk):
 
   Fix KMSAN metadata leaks on iounmap and failed ioremap allocations.  Free
   backing pages before removing their mappings, and share the teardown with
   partial-allocation cleanup.
 
 - "mm/damon/core: preserve quota state when constructing schemes"
   (Karl Mehltretter):
 
   Preserve running DAMOS quota state while validating parameter updates.
   Even rejected updates could reset accounting and exceed the quota window;
   add tests for both accepted and rejected updates.
 
 - "mm/vmalloc: fix vmalloc_dump_obj VA lookup" (Ye Liu):
 
   Fix vmalloc_dump_obj() lookups for last-page addresses and allocations
   spanning vmap zones.  These allocations were being missed in diagnostic
   output.
 
 - "mm: various (urgent?) fixes" (David Hildenbrand (Arm)):
 
   Fix mmap charge leaks and hugetlb use-after-free, wrong-address
   unmapping, stuck locks and endless faults.  Also preserve reservations on
   failed mremap and handle stale userfaultfd bits.
 
 - "maple_tree: fix maple_range_64 crashes in RCU mode" (Dimitris Charisis):
 
   Fix pointer and metadata confusion during RCU destruction of
   maple_range_64 nodes, avoiding double frees and invalid accesses.  Add a
   regression test; no in-tree user currently uses this combination.
 
 - "mm: fix hugetlb NR_HUGETLB accounting on folio migration" (Hongfu Li):
 
   Fix hugetlb migration and preallocation accounting so /proc/vmstat
   retains the correct count and memory.numa_stat follows the folio to its
   new node.
 
 - "mm/damon: fix a minor bug, clean code, and add a test" (SJ Park):
 
   Fix 32-bit DAMON age overflow which made old regions look young.  Share
   hugetlb folio acquisition code and add a regression test for the
   previously fixed last-region skipping bug.
 
 - "mm/damon/core: cleanup code, reduce stack usage, and add kunit"
   (SJ Park):
 
   Reduce kdamond stack usage and remove unused enums.  Add deterministic
   PSI quota-goal tests which do not depend on the machine's current memory
   pressure.
 
 - "mm/damon: fix the temporal goal tuner's size quota conversion"
   (Donggeun Yoo):
 
   Bound the temporal tuner's quota conversion to prevent overflow and zero
   effective quotas, which could stop schemes making progress.  Add boundary
   tests.
 
 - "Don't use GFP_DMA when calling dma_alloc_coherent" (Baoquan He):
 
   Remove redundant GFP_DMA flags from coherent DMA allocation calls.  The
   DMA API already selects the zone from device limits and ignores the
   caller's flag.
 
 - "kselftest: mm: fix intermittent failure khugepaged test" (Yeoreum Yun):
 
   Propagate child-process failures in the khugepaged tests and prevent
   background collapse from racing their checks.  This removes false passes
   and intermittent failures.
 
 - "MAINTAINERS: cover all hugetlb headers under HUGETLB SUBSYSTEM"
   (Enze Li):
 
   Cover all hugetlb headers in MAINTAINERS so get_maintainer.pl finds the
   right maintainers.  Also label the closing hugetlb_cgroup.h include
   guard.
 
 Summary of the 65 singletons in this merge:
 
 The singletons include a few worthwhile performance fixes. Avoiding
 unnecessary reverse-map tree updates gave a reported 15.9% improvement
 in UnixBench's execl test on a 192-core x86 system. A reclaim retry fix
 stops defrag_mode from spinning under memory.low protection; a reported
 file-creation stress test ran 5.7 times faster, with far less memory
 pressure. Narrower hugetlb invalidations also spare KVM guests needless
 refaults: the reported Redis-in-VM P99 QPS penalty while punching holes
 fell from 7.09% to 1.45%.
 
 Several fixes prevent lost data or corrupted memory. Lazyfree huge-page
 races with mremap()/munmap() could lose data or access freed memory, and
 MADV_COLD could lose a concurrent write's dirty bit. Another fix
 prevents stale migration entries from outliving large folios. On
 filesystems with blocks smaller than a page, extending a file by 4 GiB
 or more could expose bytes written past the old EOF through mmap instead
 of zeroes. That is fixed, along with use-after-free races in
 PAGEMAP_SCAN during process exit and in memory-cgroup accounting on
 PREEMPT_RT kernels.
 
 Other fixes stop UFFDIO_MOVE spinning forever on pinned large folios,
 which could wedge other memory operations, and stop mremap() leaking
 commit charges until allocations fail under strict overcommit. A further
 fix keeps userfaultfd tracking intact on neighboring mappings. NUMA
 binding no longer prevents long-term pins when the chosen node has only
 movable memory, fixing QEMU/VFIO startup and io_uring buffer
 registration failures. MGLRU also gets a fix for early-boot crashes with
 memory cgroups disabled at boot, notably in small crash kernels.
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Merge tag 'mm-stable-2026-10-25-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull more MM updates from Andrew Morton:

 - "mm: make VMA flag semantics explicit, eliminate VM_SPECIAL" (Lorenzo
   Stoakes):

   Replace VM_SPECIAL with helpers describing mapping ownership and
   behavior. Enforce the mmap flag rules and convert affected drivers,
   removing ambiguous tests shared by driver mappings and ordinary
   memory.

 - "support kselftest on nommu platform" (Hajime Tazaki):

   Add opt-in mmap and mremap tests for NOMMU systems. Teach the runner
   to avoid its fork-dependent timeout command and document the build
   and runtime requirements.

 - "mm/collapse: separate a collapse from its callers" (Kiryl
   Shutsemau):

   Separate huge-page collapse from caller policy. Replace khugepaged
   identity checks with explicit permissions, and separate scanning from
   collapse with the mmap_lock drop in one place.

 - "mm: implement and use vma_has_anon_rmap(), silence KCSAN" (Lorenzo
   Stoakes):

   Provide a common helper for testing whether a VMA has anonymous
   reverse mappings. Document the locking rules, annotate intentional
   concurrent reads for KCSAN, and convert the core MM callers.

 - "mm/sparse: remove SECTION_MARKED_PRESENT and further cleanups"
   (David Hildenbrand):

   Remove SECTION_MARKED_PRESENT in favor of the early-section flag.
   Simplify sparse memory initialization, section metadata handling and
   related PFN validity checks.

 - "sh: remove NUMA and SPARSEMEM support" (Mike Rapoport):

   Remove SuperH NUMA and SPARSEMEM support. The extra memory banks have
   been unusable since the NO_BOOTMEM conversion, leaving only the code
   and data overhead.

 - "mm: Unify device DAX and HugeTLB vmemmap population paths" (Muchun
   Song):

   Unify the generic device DAX and HugeTLB vmemmap population paths and
   shared tail-page handling. Remove the duplicate DAX machinery while
   retaining the powerpc radix implementation.

 - "kselftest: mm: fix some failure of split_huge_page_test" (Yeoreum
   Yun):

   Fix huge-page split tests racing with khugepaged recollapse. Use
   pagemap and page flags instead of VMA-boundary assumptions which fail
   when glibc has already enabled THP.

 - "memcg: move memcgid refcount to objcg to unpin dying memcgs"
   (Bingfang Guo):

   Let dying memcgs be freed while swapped-out shmem still holds their
   IDs. Move ID references to reparentable objcgs, with the necessary
   swap accounting and RCU lifetime changes.

 - "mm/truncate: fix data loss when truncating straddling large folios"
   (Zhang Yi):

   Preserve out-of-range data when truncating straddling large folios.
   Fix a lookup race and split-failure handling, and handle minimum
   folio orders for the forthcoming ext4 iomap buffered I/O path.

 - "mm/damon: introduce damos quota goal target metric complement flag"
   (SJ Park):

   Let DAMOS quota goals use a metric's complement, so utilization can
   also express free-memory goals without adding separate metrics. Add
   the sysfs interface, documentation and tests.

 - "arm64/mm: Standardize printing for pgtable entries" (Anshuman
   Khandual):

   Use the generic formatter for arm64 page-table entries, ready for
   future wider entries. Move the safe-PTE-update check out of the
   header to avoid an include cycle.

 - "mm: kmsan: fix iounmap metadata teardown" (Dima Koziuk):

   Fix KMSAN metadata leaks on iounmap and failed ioremap allocations.
   Free backing pages before removing their mappings, and share the
   teardown with partial-allocation cleanup.

 - "mm/damon/core: preserve quota state when constructing schemes" (Karl
   Mehltretter):

   Preserve running DAMOS quota state while validating parameter
   updates. Even rejected updates could reset accounting and exceed the
   quota window; add tests for both accepted and rejected updates.

 - "mm/vmalloc: fix vmalloc_dump_obj VA lookup" (Ye Liu):

   Fix vmalloc_dump_obj() lookups for last-page addresses and
   allocations spanning vmap zones. These allocations were being missed
   in diagnostic output.

 - "mm: various (urgent?) fixes" (David Hildenbrand):

   Fix mmap charge leaks and hugetlb use-after-free, wrong-address
   unmapping, stuck locks and endless faults. Also preserve reservations
   on failed mremap and handle stale userfaultfd bits.

 - "maple_tree: fix maple_range_64 crashes in RCU mode" (Dimitris
   Charisis):

   Fix pointer and metadata confusion during RCU destruction of
   maple_range_64 nodes, avoiding double frees and invalid accesses. Add
   a regression test; no in-tree user currently uses this combination.

 - "mm: fix hugetlb NR_HUGETLB accounting on folio migration" (Hongfu
   Li):

   Fix hugetlb migration and preallocation accounting so /proc/vmstat
   retains the correct count and memory.numa_stat follows the folio to
   its new node.

 - "mm/damon: fix a minor bug, clean code, and add a test" (SJ Park):

   Fix 32-bit DAMON age overflow which made old regions look young.
   Share hugetlb folio acquisition code and add a regression test for
   the previously fixed last-region skipping bug.

 - "mm/damon/core: cleanup code, reduce stack usage, and add kunit" (SJ
   Park):

   Reduce kdamond stack usage and remove unused enums. Add deterministic
   PSI quota-goal tests which do not depend on the machine's current
   memory pressure.

 - "mm/damon: fix the temporal goal tuner's size quota conversion"
   (Donggeun Yoo):

   Bound the temporal tuner's quota conversion to prevent overflow and
   zero effective quotas, which could stop schemes making progress. Add
   boundary tests.

 - "Don't use GFP_DMA when calling dma_alloc_coherent" (Baoquan He):

   Remove redundant GFP_DMA flags from coherent DMA allocation calls.
   The DMA API already selects the zone from device limits and ignores
   the caller's flag.

 - "kselftest: mm: fix intermittent failure khugepaged test" (Yeoreum
   Yun):

   Propagate child-process failures in the khugepaged tests and prevent
   background collapse from racing their checks. This removes false
   passes and intermittent failures.

 - "MAINTAINERS: cover all hugetlb headers under HUGETLB SUBSYSTEM"
   (Enze Li):

   Cover all hugetlb headers in MAINTAINERS so get_maintainer.pl finds
   the right maintainers. Also label the closing hugetlb_cgroup.h
   include guard.

Summary of the 65 singletons in this merge:

  The singletons include a few worthwhile performance fixes. Avoiding
  unnecessary reverse-map tree updates gave a reported 15.9% improvement
  in UnixBench's execl test on a 192-core x86 system. A reclaim retry
  fix stops defrag_mode from spinning under memory.low protection; a
  reported file-creation stress test ran 5.7 times faster, with far less
  memory pressure. Narrower hugetlb invalidations also spare KVM guests
  needless refaults: the reported Redis-in-VM P99 QPS penalty while
  punching holes fell from 7.09% to 1.45%.

  Several fixes prevent lost data or corrupted memory. Lazyfree
  huge-page races with mremap()/munmap() could lose data or access freed
  memory, and MADV_COLD could lose a concurrent write's dirty bit.
  Another fix prevents stale migration entries from outliving large
  folios. On filesystems with blocks smaller than a page, extending a
  file by 4 GiB or more could expose bytes written past the old EOF
  through mmap instead of zeroes. That is fixed, along with
  use-after-free races in PAGEMAP_SCAN during process exit and in
  memory-cgroup accounting on PREEMPT_RT kernels.

  Other fixes stop UFFDIO_MOVE spinning forever on pinned large folios,
  which could wedge other memory operations, and stop mremap() leaking
  commit charges until allocations fail under strict overcommit. A
  further fix keeps userfaultfd tracking intact on neighboring mappings.
  NUMA binding no longer prevents long-term pins when the chosen node
  has only movable memory, fixing QEMU/VFIO startup and io_uring buffer
  registration failures. MGLRU also gets a fix for early-boot crashes
  with memory cgroups disabled at boot, notably in small crash kernels.

* tag 'mm-stable-2026-10-25-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (213 commits)
  mm: multi-gen LRU: fix NULL lruvec->pgdat deref with memcg disabled on cmdline
  mm/page_counter: use WRITE_ONCE() for emin/elow when parent is the root
  mm/memcontrol: publish null pointer before dropping css reference
  test_maple_tree: test maple_range_64 node in RCU mode
  maple_tree: fix maple_range_64 crashes in RCU mode
  mm/vma: avoid broken uffd merge on mremap
  tools/testing/shared: catch a failed posix_memalign()
  mm/damon/core: remove unreachable damos charge_{target,addr}_from
  mm/shrinker: allocate shrinker_info_unit from a dedicated kmem_cache
  riscv: mm: exclude invalid THP PMDs from page table check
  mm/damon/core: filter out damos address filter-split failed region
  fs/proc/task_mmu: pin mm_users in do_pagemap_scan()
  mm/mempolicy: apply bind policies against the scoped allocation zone
  mm/vmscan: reclaim every zone in per-node proactive reclaim
  mm/mremap: correctly uncharge accountable VMAs in error path
  mm/mremap: populate calculated fields in vrm state correctly
  MAINTAINERS: add an entry for MEMORY MANAGEMENT - MEMORY MAP
  mm: bdi: reset min_ratio after the sysfs attributes are gone
  mm/page_vma_mapped: continue past nonmatching huge PMDs
  selftests/mm: skip hugetlb cgroup v2 tests without the needed controllers
  ...
2026-10-27 12:23:17 -10:00
..
damon Docs/mm/damon/design: document damos quota goal complement flag 2026-10-24 01:56:02 -07:00
active_mm.rst Documentation: treewide: Replace marc.info links with lore 2025-11-03 16:21:31 -07:00
allocation-profiling.rst mm.git review status for linus..mm-stable 2026-08-27 09:17:06 -07:00
arch_pgtable_helpers.rst Documentation/mm: drop pxx_mkdevmap() descriptions from page table helpers 2025-10-03 16:42:44 -07:00
balance.rst Documentation/mm: fix spelling mistake 2025-03-16 22:06:23 -07:00
bootmem.rst
free_page_reporting.rst
highmem.rst
hmm.rst docs/mm: fix braces 2026-08-06 18:57:09 -07:00
hugetlbfs_reserv.rst Documentation: fix a hugetlbfs reservation statement 2026-04-05 13:53:12 -07:00
hwpoison.rst Documentation/mm/hwpoison.rst: fix typos and grammar. 2026-03-17 08:35:27 -06:00
index.rst docs/mm: describe set_memory() and set_direct_map() APIs 2026-10-12 21:26:32 -07:00
kernel-page-tables.rst docs/mm: describe set_memory() and set_direct_map() APIs 2026-10-12 21:26:32 -07:00
ksm.rst docs/mm: ksm: use the renamed ksm structure names 2026-10-08 22:54:39 -07:00
memfd_preservation.rst docs: memfd_preservation: fix rendering of ABI documentation 2026-06-07 08:40:16 +03:00
memory-model.rst arch, mm: consolidate initialization of SPARSE memory model 2026-01-26 20:02:18 -08:00
mmu_notifier.rst
multigen_lru.rst
numa.rst Documentation/mm: Fix typo in NUMA paragraph 2026-03-09 10:11:35 -06:00
oom.rst
overcommit-accounting.rst
page_allocation.rst
page_cache.rst
page_frags.rst
page_migration.rst Docs/mm: fix outdated "radix tree" in page_migration 2026-08-24 18:43:23 -07:00
page_owner.rst tools/mm/page_owner_sort: add module name sort/cull/filter support 2026-10-06 17:38:59 -07:00
page_reclaim.rst
page_table_check.rst
page_tables.rst Docs/mm: fix typos and grammar in page_tables.rst 2026-02-14 10:12:14 -07:00
physical_memory.rst mm/memory_hotplug: optimize zone contiguous check when changing pfn range 2026-09-23 16:21:54 +02:00
process_addrs.rst mm/vma: avoid spurious write locks when mm->mm_lock_seq overflows 2026-10-24 01:56:35 -07:00
remap_file_pages.rst
shmfs.rst
slab.rst doc: Add slab internal kernel-doc 2025-06-18 13:06:26 +02:00
split_page_table_lock.rst mm: pgtable: Fix grammar error 2025-02-04 09:40:14 -07:00
swap-table.rst docs/mm: add document for swap table 2025-09-21 14:22:22 -07:00
swap.rst
transhuge.rst mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT) 2025-03-17 22:06:48 -07:00
unevictable-lru.rst mm: remove isolate_lru_page() 2024-09-09 16:38:59 -07:00
vmalloc.rst
vmalloced-kernel-stacks.rst docs:mm: fixed spelling and grammar mistakes on vmalloc kernel stack page 2024-09-10 15:31:45 -06:00
vmemmap_dedup.rst Documentation/mm: update DAX vmemmap deduplication docs 2026-10-08 22:55:08 -07:00
zsmalloc.rst mm: zsmalloc: remove object mapping APIs and per-CPU map areas 2025-03-17 00:05:41 -07:00