Merge tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

- "mm, swap: improve cluster scan strategy" from Kairui Song imp

Merge tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

- "mm, swap: improve cluster scan strategy" from Kairui Song improves
performance and reduces the failure rate of swap cluster allocation

- "support large align and nid in Rust allocators" from Vitaly Wool
permits Rust allocators to set NUMA node and large alignment when
perforning slub and vmalloc reallocs

- "mm/damon/vaddr: support stat-purpose DAMOS" from Yueyang Pan extend
DAMOS_STAT's handling of the DAMON operations sets for virtual
address spaces for ops-level DAMOS filters

- "execute PROCMAP_QUERY ioctl under per-vma lock" from Suren
Baghdasaryan reduces mmap_lock contention during reads of
/proc/pid/maps

- "mm/mincore: minor clean up for swap cache checking" from Kairui Song
performs some cleanup in the swap code

- "mm: vm_normal_page*() improvements" from David Hildenbrand provides
code cleanup in the pagemap code

- "add persistent huge zero folio support" from Pankaj Raghav provides
a block layer speedup by optionalls making the
huge_zero_pagepersistent, instead of releasing it when its refcount
falls to zero

- "kho: fixes and cleanups" from Mike Rapoport adds a few touchups to
the recently added Kexec Handover feature

- "mm: make mm->flags a bitmap and 64-bit on all arches" from Lorenzo
Stoakes turns mm_struct.flags into a bitmap. To end the constant
struggle with space shortage on 32-bit conflicting with 64-bit's
needs

- "mm/swapfile.c and swap.h cleanup" from Chris Li cleans up some swap
code

- "selftests/mm: Fix false positives and skip unsupported tests" from
Donet Tom fixes a few things in our selftests code

- "prctl: extend PR_SET_THP_DISABLE to only provide THPs when advised"
from David Hildenbrand "allows individual processes to opt-out of
THP=always into THP=madvise, without affecting other workloads on the
system".

It's a long story - the [1/N] changelog spells out the considerations

- "Add and use memdesc_flags_t" from Matthew Wilcox gets us started on
the memdesc project. Please see

https://kernelnewbies.org/MatthewWilcox/Memdescs and
https://blogs.oracle.com/linux/post/introducing-memdesc

- "Tiny optimization for large read operations" from Chi Zhiling
improves the efficiency of the pagecache read path

- "Better split_huge_page_test result check" from Zi Yan improves our
folio splitting selftest code

- "test that rmap behaves as expected" from Wei Yang adds some rmap
selftests

- "remove write_cache_pages()" from Christoph Hellwig removes that
function and converts its two remaining callers

- "selftests/mm: uffd-stress fixes" from Dev Jain fixes some UFFD
selftests issues

- "introduce kernel file mapped folios" from Boris Burkov introduces
the concept of "kernel file pages". Using these permits btrfs to
account its metadata pages to the root cgroup, rather than to the
cgroups of random inappropriate tasks

- "mm/pageblock: improve readability of some pageblock handling" from
Wei Yang provides some readability improvements to the page allocator
code

- "mm/damon: support ARM32 with LPAE" from SeongJae Park teaches DAMON
to understand arm32 highmem

- "tools: testing: Use existing atomic.h for vma/maple tests" from
Brendan Jackman performs some code cleanups and deduplication under
tools/testing/

- "maple_tree: Fix testing for 32bit compiles" from Liam Howlett fixes
a couple of 32-bit issues in tools/testing/radix-tree.c

- "kasan: unify kasan_enabled() and remove arch-specific
implementations" from Sabyrzhan Tasbolatov moves KASAN arch-specific
initialization code into a common arch-neutral implementation

- "mm: remove zpool" from Johannes Weiner removes zspool - an
indirection layer which now only redirects to a single thing
(zsmalloc)

- "mm: task_stack: Stack handling cleanups" from Pasha Tatashin makes a
couple of cleanups in the fork code

- "mm: remove nth_page()" from David Hildenbrand makes rather a lot of
adjustments at various nth_page() callsites, eventually permitting
the removal of that undesirable helper function

- "introduce kasan.write_only option in hw-tags" from Yeoreum Yun
creates a KASAN read-only mode for ARM, using that architecture's
memory tagging feature. It is felt that a read-only mode KASAN is
suitable for use in production systems rather than debug-only

- "mm: hugetlb: cleanup hugetlb folio allocation" from Kefeng Wang does
some tidying in the hugetlb folio allocation code

- "mm: establish const-correctness for pointer parameters" from Max
Kellermann makes quite a number of the MM API functions more accurate
about the constness of their arguments. This was getting in the way
of subsystems (in this case CEPH) when they attempt to improving
their own const/non-const accuracy

- "Cleanup free_pages() misuse" from Vishal Moola fixes a number of
code sites which were confused over when to use free_pages() vs
__free_pages()

- "Add Rust abstraction for Maple Trees" from Alice Ryhl makes the
mapletree code accessible to Rust. Required by nouveau and by its
forthcoming successor: the new Rust Nova driver

- "selftests/mm: split_huge_page_test: split_pte_mapped_thp
improvements" from David Hildenbrand adds a fix and some cleanups to
the thp selftesting code

- "mm, swap: introduce swap table as swap cache (phase I)" from Chris
Li and Kairui Song is the first step along the path to implementing
"swap tables" - a new approach to swap allocation and state tracking
which is expected to yield speed and space improvements. This
patchset itself yields a 5-20% performance benefit in some situations

- "Some ptdesc cleanups" from Matthew Wilcox utilizes the new memdesc
layer to clean up the ptdesc code a little

- "Fix va_high_addr_switch.sh test failure" from Chunyu Hu fixes some
issues in our 5-level pagetable selftesting code

- "Minor fixes for memory allocation profiling" from Suren Baghdasaryan
addresses a couple of minor issues in relatively new memory
allocation profiling feature

- "Small cleanups" from Matthew Wilcox has a few cleanups in
preparation for more memdesc work

- "mm/damon: add addr_unit for DAMON_LRU_SORT and DAMON_RECLAIM" from
Quanmin Yan makes some changes to DAMON in furtherance of supporting
arm highmem

- "selftests/mm: Add -Wunreachable-code and fix warnings" from Muhammad
Anjum adds that compiler check to selftests code and fixes the
fallout, by removing dead code

- "Improvements to Victim Process Thawing and OOM Reaper Traversal
Order" from zhongjinji makes a number of improvements in the OOM
killer: mainly thawing a more appropriate group of victim threads so
they can release resources

- "mm/damon: misc fixups and improvements for 6.18" from SeongJae Park
is a bunch of small and unrelated fixups for DAMON

- "mm/damon: define and use DAMON initialization check function" from
SeongJae Park implement reliability and maintainability improvements
to a recently-added bug fix

- "mm/damon/stat: expose auto-tuned intervals and non-idle ages" from
SeongJae Park provides additional transparency to userspace clients
of the DAMON_STAT information

- "Expand scope of khugepaged anonymous collapse" from Dev Jain removes
some constraints on khubepaged's collapsing of anon VMAs. It also
increases the success rate of MADV_COLLAPSE against an anon vma

- "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()"
from Lorenzo Stoakes moves us further towards removal of
file_operations.mmap(). This patchset concentrates upon clearing up
the treatment of stacked filesystems

- "mm: Improve mlock tracking for large folios" from Kiryl Shutsemau
provides some fixes and improvements to mlock's tracking of large
folios. /proc/meminfo's "Mlocked" field became more accurate

- "mm/ksm: Fix incorrect accounting of KSM counters during fork" from
Donet Tom fixes several user-visible KSM stats inaccuracies across
forks and adds selftest code to verify these counters

- "mm_slot: fix the usage of mm_slot_entry" from Wei Yang addresses
some potential but presently benign issues in KSM's mm_slot handling

* tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (372 commits)
mm: swap: check for stable address space before operating on the VMA
mm: convert folio_page() back to a macro
mm/khugepaged: use start_addr/addr for improved readability
hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list
alloc_tag: fix boot failure due to NULL pointer dereference
mm: silence data-race in update_hiwater_rss
mm/memory-failure: don't select MEMORY_ISOLATION
mm/khugepaged: remove definition of struct khugepaged_mm_slot
mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL
hugetlb: increase number of reserving hugepages via cmdline
selftests/mm: add fork inheritance test for ksm_merging_pages counter
mm/ksm: fix incorrect KSM counter handling in mm_struct during fork
drivers/base/node: fix double free in register_one_node()
mm: remove PMD alignment constraint in execmem_vmalloc()
mm/memory_hotplug: fix typo 'esecially' -> 'especially'
mm/rmap: improve mlock tracking for large folios
mm/filemap: map entire large folio faultaround
mm/fault: try to map the entire file folio in finish_fault()
mm/rmap: mlock large folios in try_to_unmap_one()
mm/rmap: fix a mlock race condition in folio_referenced_one()
...

show more ...

selftests: prctl: introduce tests for disabling THPs except for madvise

The test will set the global system THP setting to never, madvise or
always depending on the fixture variant and the 2M settin

selftests: prctl: introduce tests for disabling THPs except for madvise

The test will set the global system THP setting to never, madvise or
always depending on the fixture variant and the 2M setting to inherit
before it starts (and reset to original at teardown). The fixture setup
will also test if PR_SET_THP_DISABLE prctl call can be made with
PR_THP_DISABLE_EXCEPT_ADVISED and skip if it fails.

This tests if the process can:
- successfully get the policy to disable THPs expect for madvise.
- get hugepages only on MADV_HUGE and MADV_COLLAPSE if the global policy
is madvise/always and only with MADV_COLLAPSE if the global policy is
never.
- successfully reset the policy of the process.
- after reset, only get hugepages with:
- MADV_COLLAPSE when policy is set to never.
- MADV_HUGE and MADV_COLLAPSE when policy is set to madvise.
- always when policy is set to "always".
- never get a THP with MADV_NOHUGEPAGE.
- repeat the above tests in a forked process to make sure the policy is
carried across forks.

Test results:
./prctl_thp_disable
TAP version 13
1..12
ok 1 prctl_thp_disable_completely.never.nofork
ok 2 prctl_thp_disable_completely.never.fork
ok 3 prctl_thp_disable_completely.madvise.nofork
ok 4 prctl_thp_disable_completely.madvise.fork
ok 5 prctl_thp_disable_completely.always.nofork
ok 6 prctl_thp_disable_completely.always.fork
ok 7 prctl_thp_disable_except_madvise.never.nofork
ok 8 prctl_thp_disable_except_madvise.never.fork
ok 9 prctl_thp_disable_except_madvise.madvise.nofork
ok 10 prctl_thp_disable_except_madvise.madvise.fork
ok 11 prctl_thp_disable_except_madvise.always.nofork
ok 12 prctl_thp_disable_except_madvise.always.fork

[usamaarif642@gmail.com: return after executing test in child process]
Link: https://lkml.kernel.org/r/3dca2de4-9a6a-4efe-a86c-83f9509831fc@gmail.com
Link: https://lkml.kernel.org/r/20250815135549.130506-8-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yafang <laoar.shao@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

selftests: prctl: introduce tests for disabling THPs completely

The test will set the global system THP setting to never, madvise or
always depending on the fixture variant and the 2M setting to inh

selftests: prctl: introduce tests for disabling THPs completely

The test will set the global system THP setting to never, madvise or
always depending on the fixture variant and the 2M setting to inherit
before it starts (and reset to original at teardown). The fixture setup
will also test if PR_SET_THP_DISABLE prctl call can be made to disable all
THPs and skip if it fails.

This tests if the process can:
- successfully get the policy to disable THPs completely.
- never get a hugepage when the THPs are completely disabled
with the prctl, including with MADV_HUGE and MADV_COLLAPSE.
- successfully reset the policy of the process.
- after reset, only get hugepages with:
- MADV_COLLAPSE when policy is set to never.
- MADV_HUGE and MADV_COLLAPSE when policy is set to madvise.
- always when policy is set to "always".
- never get a THP with MADV_NOHUGEPAGE.
- repeat the above tests in a forked process to make sure
the policy is carried across forks.

[usamaarif642@gmail.com: return after executing test in child process]
Link: https://lkml.kernel.org/r/2d0ea708-ecba-4021-b6ca-e93f1413d60a@gmail.com
[usamaarif642@gmail.com: include linux/mman.h for prctl_thp_disable]
Link: https://lkml.kernel.org/r/20250910204609.1720498-1-usamaarif642@gmail.com
Link: https://lore.kernel.org/all/c8249725-e91d-4c51-b9bb-40305e61e20d@sirena.org.uk/
Link: https://lkml.kernel.org/r/20250815135549.130506-7-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yafang <laoar.shao@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...