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)

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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selftests/mm: add folio_split() and filemap_get_entry() race test

The added folio_split_race_test is a modified C port of the race condition
test from [1]. The test creates shmem huge pages, where

selftests/mm: add folio_split() and filemap_get_entry() race test

The added folio_split_race_test is a modified C port of the race condition
test from [1]. The test creates shmem huge pages, where the main thread
punches holes in the shmem to cause folio_split() in the kernel and a set
of 16 threads reads the shmem to cause filemap_get_entry() in the kernel.
filemap_get_entry() reads the folio and xarray split by folio_split()
locklessly. The original test[2] is written in rust and uses memfd (shmem
backed). This C port uses shmem directly and use a single process.

Note: the initial rust to C conversion is done by Cursor.

Link: https://lore.kernel.org/all/CAKNNEtw5_kZomhkugedKMPOG-sxs5Q5OLumWJdiWXv+C9Yct0w@mail.gmail.com/ [1]
Link: https://github.com/dfinity/thp-madv-remove-test [2]
Link: https://lkml.kernel.org/r/20260323163717.184107-1-ziy@nvidia.com
Co-developed-by: Bas van Dijk <bas@dfinity.org>
Signed-off-by: Bas van Dijk <bas@dfinity.org>
Co-developed-by: Adam Bratschi-Kaye <adam.bratschikaye@dfinity.org>
Signed-off-by: Adam Bratschi-Kaye <adam.bratschikaye@dfinity.org>
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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