linux-toradex.git/arch/powerpc/mm, branch master

Merge tag 'mm-stable-2026-10-25-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-10-27T22:23:17+00:00

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
...

mm/sparse-vmemmap: drop Device DAX-specific population path

2026-10-24T08:56:36+00:00

The common vmemmap path selects the shared page for optimized mappings
itself, so Device DAX no longer needs vmemmap_populate_compound_pages() to
find a shared tail page and pass its backing PFN through the generic
population helpers.

Remove the Device DAX-specific population path and let section memmap
population always use vmemmap_populate().  The powerpc retains an
architecture-specific compound-page implementation, so select it directly
from radix__vmemmap_populate() for optimizable sections.

Link: https://lore.kernel.org/20261010075755.83339-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Signed-off-by: Andrew Morton 
Reviewed-by: Lance Yang 
Acked-by: Qi Zheng 
Cc: Madhavan Srinivasan 
Cc: Mike Rapoport 
Cc: David Hildenbrand 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Christophe Leroy 
Cc: Ritesh Harjani (IBM) 
Cc: Shrikanth Hegde 
Cc: Lorenzo Stoakes 
Cc: Liam R. Howlett 
Cc: Vlastimil Babka 
Cc: Suren Baghdasaryan 
Cc: Michal Hocko

mm: rename is_vm_hugetlb_page() to vma_is_hugetlb()

2026-10-24T08:56:18+00:00

The is_vm_hugetlb_page() predicate is badly named - the mapping can span
more than a page and it is inconsistent with other VMA predicates that
typically are prefixed by vma_.

Rename to vma_is_hugetlb() for consistency, and while we're here update
some VM_BUG_ON_VMA() to VM_WARN_ON_ONCE_VMA() as to avoid unnecessary
oopses.

No functional change intended.

Link: https://lore.kernel.org/20261013-b4-mmap-prepare-vma-flag-sanify-v6-28-1aa3c9b139f9@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) 
Signed-off-by: Andrew Morton 
Acked-by: Marc Zyngier 
Acked-by: Claudio Imbrenda 
Acked-by: Anup Patel 
Acked-by: Zi Yan 
Acked-by: David Hildenbrand (Arm) 
Cc: Liam R. Howlett 
Cc: Vlastimil Babka 
Cc: Jann Horn 
Cc: Pedro Falcato 
Cc: Mike Rapoport 
Cc: Suren Baghdasaryan 
Cc: Michal Hocko 
Cc: Jonathan Corbet 
Cc: Greg Kroah-Hartman 
Cc: Dennis Dalessandro 
Cc: Jason Gunthorpe 
Cc: Leon Romanovsky 
Cc: Paul Moore 
Cc: Stephen Smalley 
Cc: Jaroslav Kysela 
Cc: Takashi Iwai 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Andrii Nakryiko 
Cc: Eduard Zingerman 
Cc: Kumar Kartikeya Dwivedi 
Cc: Baolin Wang 
Cc: Nico Pache 
Cc: Ryan Roberts 
Cc: Dev Jain 
Cc: Barry Song 
Cc: Lance Yang 
Cc: Usama Arif 
Cc: Kiryl Shutsemau 
Cc: Doug Gilbert 
Cc: James Bottomley 
Cc: Martin K. Petersen 
Cc: Simona Vetter 
Cc: Helge Deller 
Cc: Sebastian Reichel 
Cc: John Hubbard 
Cc: Peter Xu 
Cc: Masami Hiramatsu 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: Arnaldo Carvalho de Melo 
Cc: Namhyung Kim 
Cc: Mark Rutland 
Cc: Rik van Riel 
Cc: Harry Yoo 
Cc: Juri Lelli 
Cc: Vincent Guittot 
Cc: Maarten Lankhorst 
Cc: Maxime Ripard 
Cc: Thomas Zimmermann 
Cc: David Airlie 
Cc: Will Deacon 
Cc: Aneesh Kumar K.V 
Cc: Nicholas Piggin 
Cc: Arnd Bergmann 
Cc: Muchun Song 
Cc: Oscar Salvador 
Cc: Matthew Wilcox (Oracle) 
Cc: Jan Kara 
Cc: Oliver Upton 
Cc: Catalin Marinas 
Cc: Madhavan Srinivasan 
Cc: Paul Walmsley 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Christian Borntraeger 
Cc: Janosch Frank 
Cc: Alexander Gordeev 
Cc: Gerald Schaefer 
Cc: Heiko Carstens 
Cc: Vasily Gorbik 
Cc: David S. Miller 
Cc: Andreas Larsson 
Cc: Al Viro 
Cc: Christian Brauner 
Cc: Matthew Brost 
Cc: Joshua Hahn 
Cc: Rakie Kim 
Cc: Byungchul Park 
Cc: Gregory Price 
Cc: Ying Huang 
Cc: Alistair Popple 
Cc: Chris Li 
Cc: Kairui Song 
Cc: Kemeng Shi 
Cc: Nhat Pham 
Cc: Baoquan He 
Cc: Youngjun Park 
Cc: Johannes Weiner 
Cc: Qi Zheng 
Cc: Shakeel Butt 
Cc: Axel Rasmussen 
Cc: Yuanchu Xie 
Cc: Wei Xu 
Cc: Chengming Zhou 
Cc: Michal Hocko 
Cc: Miklos Szeredi 
Cc: Xu Xin 
Cc: Ihor Solodrai 
Cc: Bert Karwatzki

arch, mm: promote DEBUG_WX to CHECK_WX

2026-10-24T08:55:54+00:00

Verification that the kernel does not have writable + executable mappings
is about detecting security risks rather than a pure debug feature.

Major distribution configurations enable it in their kernels as well as
defconfigs of most architectures that have ARCH_HAS_DEBUG_WX.

Rename relevant generic configuration options to use CHECK_WX and move
their definitions from mm/Kconfig.debug to mm/Kconfig.

Rename *debug_checkwx() funcitons and macros to *pgtable_checkwx().

For arm that does not widely enable it, only rename its variants of the
config options.

Enabling CHECK_WX adds a few kilobytes to the kernel binary and while the
added size can be slightly reduced with churny updates of architecture
implementations of ptdump, the core functionality takes most of the added
size.  It cannot be moved to .init.text because the verification has to
happen after init sections are freed.

With this, make generic CHECK_WX default to STRICT_KERNEL_RWX while
still leaving users targeting small kernels the possibility to opt-out.

Link: https://lore.kernel.org/20260926-direct-map-verify-wx-v2-1-efcd64a6b74a@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) 
Signed-off-by: Andrew Morton 
Suggested-by: Dave Hansen 
Acked-by: Lorenzo Stoakes (ARM) 
Acked-by: Dave Hansen 
Acked-by: David Hildenbrand (Arm) 
Reviewed-by: Anshuman Khandual 
Cc: Albert Ou 
Cc: Alexander Gordeev 
Cc: Alexandre Ghiti 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Christophe Leroy 
Cc: Christian Borntraeger 
Cc: Gerald Schaefer 
Cc: Heiko Carstens 
Cc: Ingo Molnar 
Cc: Liam R. Howlett 
Cc: Madhavan Srinivasan 
Cc: Mark Rutland 
Cc: Michael Ellerman 
Cc: Michal Hocko 
Cc: Nicholas Piggin 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: H. Peter Anvin 
Cc: Ritesh Harjani (IBM) 
Cc: Russell King 
Cc: Shrikanth Hegde 
Cc: Suren Baghdasaryan 
Cc: Sven Schnelle 
Cc: Thomas Gleixner 
Cc: Vasily Gorbik 
Cc: Vlastimil Babka 
Cc: Will Deacon

Merge tag 'mm-stable-2026-10-19-21-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-10-23T17:42:11+00:00

Pull MM updates from Andrew Morton:

- "selftests/mm: improve khugepaged coverage" (Kiryl Shutsemau):

Give khugepaged a proper workout. Extend the tests to all supported
mTHP orders, check exactly which windows collapsed, and make scan
completion deterministic. Race collapse against faults, pinning, fork
and remap; verify that the contents survive.

Add coverage for whole-page-table zaps and memory pressure too.

- "selftests/mm: separate GUP microbenchmarking from functional testing"
(Sarthak Sharma):

Untangle GUP benchmarking from correctness testing. Move the
benchmark into tools/mm, add a standalone harness-based GUP selftest,
and move shared helpers into tools/lib/mm. Give each tool one job
instead of mixing timing measurements with correctness checks.

Cover the mapping, pinning and batch-size combinations explicitly.

- "mm: Switch device DAX to section-based vmemmap optimization" (Muchun
Song):

Apply section-based vmemmap optimization to device DAX. Rework the
backing metadata layout to save memory while preserving the handling
of device memory hotplug and its different alignment and lifetime
requirements.

- "mm: Introduce section-based vmemmap optimization for HugeTLB"
(Muchun Song):

Cut the memory consumed by HugeTLB's struct page array with
section-based vmemmap optimization. Arrange the metadata so large
huge pages need fewer backing pages, while keeping initialization,
teardown and the various hugepage configurations straight.

- "mm/huge_memory: clean up and decouple the anon and file split
helpers" (Kairui Song):

Separate anonymous and file-backed folio splitting, which have rather
different locking and bookkeeping requirements. Move the work into
separate helpers, drop dead checks and tidy swap-cache handling. Fix
error paths, including one that could leave a folio frozen.

Keep the swap cache cases separate from file-cache splitting.

- "mm: Unconditional per-VMA locks and cleanups" (Dave Hansen):

Make per-VMA locking unconditional and clean up the old conditional
code around it. This removes configuration-dependent plumbing and
lets callers depend on one locking model rather than carrying both
cases along.

- "memcg: remove the v1 soft limit" (Shakeel Butt):

Remove the old cgroup v1 memory soft-limit machinery. This has long
since been superseded by the newer memory-control interfaces; hauling
around a separate reclaim scheme for it no longer buys us much.

- "read proc/pid/smaps_rollup under per-vma lock" (Suren Baghdasaryan):

Read /proc/PID/smaps_rollup using per-VMA locks where possible,
rather than holding mmap_lock across the entire walk. Retain the
contention fallback and add tearing tests. This considerably reduces
latency when another thread is busy changing its mappings.

- "mm/damon: introduce data access-as-a-data attribute" (SJ Park):

Teach DAMON to expose memory access observations as data attributes,
making them available to the probe and filtering machinery. Extend
the interfaces, documentation and tests so the new information can be
used rather than merely collected.

- "Remove PG_private by using page/folio->private checks instead" (Zi
Yan):

Get rid of PG_private and use the folio's private pointer to say
whether private data is attached. Convert the filesystem users,
including erofs, f2fs and md, and clean up the old accessors and
flags. There are a few special cases, notably swapcache and hugetlb,
which need explicit care.

- "mm: make userland page table freeing RCU-safe" (Lorenzo Stoakes):

Make freeing userspace page tables safe against RCU readers. Sort out
the page-table lifetime and locking rules so walkers cannot stumble
over freed tables while mappings are being torn down.

- "make unused huge shrinker memcg aware" (Qi Zheng):

Make shmem's unused-huge-folio shrinker aware of memory cgroups, so
reclaim can find those folios under the right memcg. Wire up the
per-memcg tracking and its lifetime rules, and give the shrinklist
its own lockdep class to avoid spurious dependency reports.

- "mm: Drop pxd_ERROR()" (Anshuman Khandual):

Remove the old pxd_ERROR() page-table checks and their
architecture-specific baggage. Simplify the common page-table
interfaces and callers now that these checks no longer serve a
useful purpose.

- "memcg: group struct fields by access pattern" (Shakeel Butt):

Rearrange memcg's hot and cold fields according to how they're
actually accessed. Keep frequently updated counters and their
neighboring state from fighting over cachelines and reduce needless
cacheline traffic.

- "mm/damon/core: fix the size charged for a filter-trimmed region"
(Donggeun Yoo):

Fix DAMOS quota accounting when a filter trims a monitoring region.
Charge only the part left after filtering, not the original region,
and add KUnit coverage. Previously the excluded memory could eat into
the quota and make schemes run more slowly than requested.

- "mm/damon: add kunit and selftests for probes and probe weights" (SJ
Park):

Add more tests for DAMON probes and their weights, including
validation and the results reported to userspace. This is mostly
about catching regressions in the newer probe infrastructure before
they become harder to diagnose.

- "mm: memcontrol: constify the read side of the read side of the memcg
API" (Tal Zussman):

Mark the read-only parts of the memcg interface const, from folio and
lruvec accessors to counters and swap helpers. Most of this is
mechanical, but it makes the contracts clearer and lets the compiler
catch accidental writes.

- "mm/damon/vaddr: support {prep,apply}_probes" (SJ Park):

Support the new prepare/apply probe operations in DAMON's
virtual-address backend. This brings vaddr monitoring into line with
the probe infrastructure and makes the added probe types useful there
too.

- "mm/mglru: clean up folio counters and flag usage" (Kairui Song):

Simplify MGLRU's folio counters and flag handling. Remove redundant
accounting paths and make the state transitions easier to follow
without changing the intended reclaim policy.

- "arch, mm/execmem: resolve confusion about set_direct_map_valid_noflush()"
(Mike Rapoport (Microsoft)):

Clarify and straighten out the set_direct_map_valid_noflush()
interface across architectures and execmem. Make the requested
mapping changes and the callers' expectations agree, rather than
relying on subtly different architecture behavior.

- "mm: zswap: free cold writeback folios promptly" (Alexandre Ghiti):

Free zswap writeback folios as soon as their disk write completes.
They are cold temporary buffers, so putting them on the LRU only
makes reclaim rediscover them later. Extend swap-cache dropbehind and
let zswap keep these folios off the LRU altogether.

- "mm: gup: cleanup gup_fast call chain" (Aristeu Rozanski):

Clean up the GUP-fast call chain and simplify how the fast-path
helpers pass their arguments and results around. Keep the page-pin
behavior the same while making the call sequence easier to maintain.

- "mm: optimize zone-device memmap initialization" (Li Zhe):

Speed up initialization of zone-device struct pages. Avoid redundant
work when setting up large device-memory ranges, where touching every
descriptor can get expensive.

- "mm/zswap: shrink zswap_entry via a pool id" (Jianyue Wu):

Reduce the size of zswap_entry by storing a compact pool identifier
instead of a full pointer. Keep the pool lookup and lifetime handling
correct while saving per-entry metadata.

- "mm/damon: support access monitoring of hugetlb-backed memory"
(Krishna Iyer):

Let DAMON monitor hugetlb-backed memory too. Extend the relevant
access checks and add coverage so those mappings no longer fall
through a hole in the monitoring machinery.

- "mm/execmem: fixes and cleanups for the ROX cache" (Mike Rapoport):

Tidy execmem's read-only-executable cache and fix its handling of the
awkward allocation and release cases. The aim is to make the cache's
ownership and permission transitions more predictable.

- "zsmallc: remove old object read API" (Sergey Senozhatsky):

Drop zsmalloc's old object-read API and move its remaining users to
the supported access mechanism. This removes a duplicate interface
which we no longer need.

- "mm/mempolicy: stop copying state in the interleave paths" (Gregory
Price):

Stop copying mempolicy state in the interleave paths when a reference
to the existing policy will do. This avoids extra work and makes the
ownership rules less obscure.

- "mm/mglru: speed up inc_min_seq() and fix cold/hot inversions" (Barry
Song):

Make MGLRU's generation advancement cheaper and fix cases where cold
and hot folios end up in the wrong order. Adjust the counter and list
handling so reclaim doesn't keep passing over the better eviction
candidates.

- "mm: Fix MF_DELAYED handling on memory failure" (Lisa Wang):

Treat MF_DELAYED as a partially completed memory-failure operation,
not an outright failure. Propagate that result correctly through
shmem and the generic handler, fix the extra-reference accounting,
and add tests for the resulting SIGBUS behavior.

- "tools/mm/page_owner_sort: fix --sort, add module filter, improve
usage" (Ye Liu):

Fix page_owner_sort's --sort handling, add module-based filtering and
make the usage output more helpful. This makes the tool less
frustrating when tracking down who is holding on to pages.

- "mm/damon: move damos filter range arguments validation to core" (SJ
Park):

Move DAMOS filter range validation into the core, where all callers
can share it. Also close the sysfs read-twice races which could pass
inconsistent ranges, and add tests for invalid input.

- "mm/damon: misc cleanups" (Zenghui Yu):

Clean up a collection of small DAMON rough edges in the core,
interfaces and tests. No large behavior change here, just simpler
code and fewer opportunities for confusion.

- "mm/damon: cleanup code, add test cases, and update guidances in
docs" (SJ Park):

Clean up DAMON's core and interfaces, add missing test cases and
bring the documentation into line with the code. These changes should
make the newer facilities easier to understand and maintain.

- "mm/damon: introduce hugepage_size probe filter" (SJ Park):

Add a DAMON probe filter for hugepage size. Let users select a range
of folio sizes through sysfs, validate the range and document the new
interface, so monitoring can concentrate on memory backed by the
desired hugepage sizes.

- "selftests/mm: pagemap_ioctl test fixes and cleanups" (Zenghui Yu):

Fix some pagemap ioctl test assumptions and clean up their setup and
reporting. Make failures point to the operation that went wrong
rather than to test harness bookkeeping.

- "mm: avoid large folio splits when swap is unavailable" (Johannes
Weiner):

Avoid splitting large folios merely to attempt swap when no swap
space is available. There is little point paying for an expensive
split when reclaim cannot actually swap the resulting pages out.

- "mm: workingset: fix the shadow node budget under MGLRU" (Hui Zhu):

Fix the workingset shadow-node budget with MGLRU enabled. Keep the
shadow entries within the intended limits so refault tracking does
not quietly consume more metadata than it should.

- "selftests/mm: TAP output and global-state fixes" (Song Hu):

Fix selftests which produce misleading TAP output or fail to restore
global settings after a run. A test ought to leave the system as it
found it, particularly when a whole suite follows behind.

- "mm: remove page_swap_entry()" (Tal Zussman):

Remove page_swap_entry() and convert its remaining users to the folio
and swap-entry helpers. Lose an old page-level interface and make the
swap paths a little more consistent.

- "mm: refactor zonelist constructors and iterators" (Gregory Price):

Refactor the zonelist construction and walk helpers to reduce
duplicated logic. Keep the allocation ordering rules intact while
making it clearer how zones are selected.

- "mm: kmemleak: batch the struct page scan" (Breno Leitao):

Scan adjacent struct pages in batches instead of taking kmemleak_lock
once for every single page. This preserves scan coverage and the
lock-hold bound, while cutting overhead substantially on debug
kernels.

- "mm/damon: misc improvements in tests and documents" (Zenghui Yu):

Fix some DAMON selftests which leave kdamond running or fail under
Python safe-path mode, and improve the KUnit coverage and
documentation. Nothing especially glamorous, but these are worth
doing.

- "mm/damon: introduce probe_hits_wsum DAMOS core filter" (SJ Park):

Add a DAMOS core filter using weighted probe-hit counts. This gives
schemes another way to select regions based on what the monitoring
probes observed.

- "mm/mglru: fix ineffective memory protection for non-kswapd reclaim"
(Ridong Chen):

Fix MGLRU's memory protection handling for reclaim outside kswapd.
The protection settings weren't having the intended effect in these
paths, leaving protected memory more exposed than requested.

- "mm/damon: improve readability, clarity and test coverage" (SJ Park):

Simplify a handful of DAMON core helpers, clarify their behavior and
expand test coverage. There are no intended userspace-visible changes
in this batch.

- "mm: replace PF_KCOMPACTD/PF_KSWAPD with kthread_func()" (Kefeng
Wang):

Stop identifying reclaim and compaction workers through the PF_KSWAPD
and PF_KCOMPACTD task flags. Use their kthread functions instead and
remove the redundant flag plumbing.

- "mm/hugetlb: fix surplus accounting and availability checks during
demotion" (Longlong Xia):

Fix HugeTLB surplus accounting and availability checks when demoting
huge pages. Keep the counters and reservation decisions consistent as
one huge page turns into several smaller ones.

- "mm/damon: add kunit tests for probe_hits handling and probe params
validation" (Jason Angelov):

Add KUnit tests for DAMON probe-hit handling and invalid probe
parameters. These cover edge cases that were too easy to miss in
ordinary monitoring tests.

- "mm/damon: fix misc bugs in kunit, quota goals and sysfs refresh_ms"
(SJ Park):

Fix a few DAMON bugs in KUnit tests, quota-goal handling and the
sysfs refresh interval. Small fixes, but the incorrect results and
control behavior were real.

- "mm: zswap: optimize zswap invalidate and store" (Kefeng Wang):

Simplify zswap's invalidate and store paths to avoid avoidable
lookups and work. Keep the entry lifetime rules intact while making
those frequent operations cheaper.

- "mm: replace custom ratelimiting logic" (Pedro Falcato):

Replace hand-rolled MM rate limiting with the common kernel helpers.
There is no need to maintain another local version of the same
mechanism.

- "mm/vmalloc: minor cleanups" (Ye Liu):

Tidy some vmalloc initialization and reporting code, and pull
duplicated vmap-area insertion work into a helper. No functional
changes are intended.

- "mm/mglru: clean up isolate_folios for readability and clarity"
(Ridong Chen):

Clean up MGLRU's isolate_folios() so the decisions are easier to read
and verify. Keep reclaim behavior unchanged while removing
unnecessary twists in the control flow.

- "Catch automatic storage in IDA and Maple Tree definitions" (Yury
Norov):

Catch IDA and maple-tree definitions placed in automatic storage
where the lifetime rules are wrong or easy to get wrong. Add checks
so such mistakes are harder to slip through unnoticed.

- "mm, swap: some random fixes and cleanups" (Kemeng Shi):

Fix and simplify a few unrelated swap paths, removing redundant work
and tidying up error handling. A small collection of things which
were better fixed than left lying around.

- "mm/page_io: folio conversion cleanups" (Tal Zussman):

Finish some page-to-folio conversions in swap I/O, removing obsolete
wrappers and using folio operations consistently. The I/O behavior is
intended to remain the same.

- "mm/swap: skip empty clusters in the swapoff scan" (Youngjun Park):

Skip empty swap clusters during swapoff instead of walking slots
which have nothing to release. This avoids pointless work on sparsely
used swap devices.

- "mm: trace: decode architecture-specific VMA flags" (Meijing Zhao):

Teach the VMA trace output to decode architecture-specific flags,
rather than leaving them as unexplained bits. That should make
tracing a good deal more useful when debugging unusual mappings.

- "mm, swap: don't spin on a bad swap entry" (Breno Leitao):

Stop repeatedly retrying a swap entry which is already known to be
bad. Make the error path terminate cleanly instead of wasting CPU
chasing an entry that cannot be used.

- "mm/page_isolation: fix UBSAN shift-out-of-bounds in
isolate_single_pageblock" (Qi Xi):

Fix an out-of-range shift in isolate_single_pageblock() and tighten
its associated boundary handling. UBSAN found the issue; the result
should be more robust pageblock isolation.

- "mm: khugepaged: fix tracepoint UAF" (Vernon Yang):

Fix a use-after-free in khugepaged tracepoint handling. Make sure the
information recorded by tracing stays valid for as long as the trace
event needs it.

- "mm/damon: fix DAMOS bugs in core, paddr and vaddr" (SJ Park):

Fix several DAMOS problems across the core and physical- and
virtual-address backends. The changes close error cases and bring the
implementations back into agreement.

- "mm/hugetlb_cgroup: move the per-node usage along with the folio"
(Hongfu Li):

Move HugeTLB per-node usage accounting when folios migrate between
nodes or are reparented to another cgroup. Otherwise numa_stat can
retain stale charges and even underflow when the folio is freed.

- "docs/core-api: memory-allocation: add k[mz]alloc_obj() and clarify
kmalloc" (Mike Rapoport):

Document the typed k[mz]alloc_obj() allocation helpers and clear up
some kmalloc guidance. Make it easier for callers to choose the right
interface.

- "selftests/mm: Validate selections and scope memfd_secret setup"
(Tianyi Chen):

Check selftest selections before running and confine memfd_secret
setup to the cases that actually need it. Avoid confusing failures
caused by the test harness itself.

- "mm/damon: move zero damos quota target_value handling to the core
layer" (SJ Park):

Handle a zero DAMOS quota goal target in the core rather than making
each user of the interface invent its own rule. Keep quota decisions
consistent across callers.

- "mm/damon: Introduce a huge page collapsing mechanism using auto
tuning" (Asier Gutierrez):

Add an auto-tuned DAMON mechanism for collapsing huge pages. Use
monitoring feedback to decide when collapse is worthwhile rather than
forcing one fixed policy onto every workload.

- "kmemleak: fix stale documentation and raise the verbose default"
(Breno Leitao):

Bring the kmemleak documentation up to date and require a third
confirming scan before verbose kernels print a suspected leak. The
extra scan helps suppress transient false positives in noisy debug
builds.

- "mm/memory: improve insert_pages() error handling" (Avi Weiss):

Tighten insert_pages() error handling so partial failures are
reported and cleaned up consistently. The caller should not have to
guess how far the operation got.

- "mm/damon: allow NULL or unstarted damon_ctx parameter for
damon_call()" (SJ Park):

Make damon_call() handle NULL and not-yet-started contexts safely.
Simplify the rules for callers and avoid an indefinite wait on an
invalid state.

- "mm/damon: introduce pgidle_set probe filter type" (SJ Park):

Add a pgidle_set DAMON probe filter, giving monitoring users another
way to select pages by their idle-tracking state. Wire it through the
filter interfaces and tests.

- "mm/damon/core: remove unused helper functions" (Cheng-Han Wu):

Remove DAMON core helpers which no longer have callers. Keep the API
surface smaller rather than retaining dead code just in case.

- "mm: stop calling pmd_folio() on special PMDs" (Gregory Price):

Avoid calling pmd_folio() on special PMD mappings that have no struct
page. The old assumption could fault in procfs walkers; use the
normal-folio checks and handle those mappings properly.

- "mm: remove three unused helpers from mm.h" (Tal Zussman):

Remove three unused helpers from mm.h. Fewer obsolete interfaces for
the next person to stumble over.

- "mm/damon: improvements in efficiency, error handling, documents"
(Liew Rui Yan):

Skip needless DAMOS quota work once the quota is full, propagate a
missing sysfs error and tidy a couple of comments. The ignored error
could make a monitoring-start request appear successful when it
wasn't.

- "docs/mm/damon/design: add explanation of nr_snapshots" (Liew Rui
Yan):

Explain DAMON's nr_snapshots accounting in the design documentation
and straighten out the associated terminology. Make it clearer what
users should expect from that counter.

- "selftests/cgroup: fixes for test_zswap on single core VM" (Wilson
Felipe Pereira):

Fix two test_zswap failures on single-CPU VMs. Wait for the exiting
child's cgroup to become unpopulated before reconfiguring it, and
avoid another test assumption which breaks under constrained
scheduling.

- "docs/ksm: fix advisor documentation and comment" (Jinjiang Tu):

Correct the KSM advisor documentation and a misleading code comment.
Keep the description aligned with how the advisor actually works.

- "Fix bugs in HugeTLB allocation when mem_cgroup_charge_hugetlb()
fails" (Ackerley Tng):

Fix HugeTLB allocation cleanup when the memcg charge fails. Make sure
failure exits undo what was allocated rather than leaving stale
accounting or resources behind.

- "mm, memcg: fix memory.peak reset clobbering other fds' watermark"
(Ridong Chen):

Fix memory.peak reset handling so resetting one file descriptor
doesn't overwrite the watermark kept for another. Keep those per-open
measurements independent as intended.

- "mm: reject zone device folios in more folio walkers" (Gregory
Price):

Reject zone-device folios in page walkers that cannot safely handle
them. Extend the existing checks rather than assuming every folio has
ordinary system-memory backing.

- "percpu: remove code with no effect" (Sang-Heon Jeon):

Remove a few pieces of percpu code which no longer do anything. There
is no reason to keep maintaining dead paths.

* tag 'mm-stable-2026-10-19-21-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (539 commits)
mm: shmem: assign a lock class to the unused huge shrinklist
mm: vmscan: put rotation-missed folios at the LRU tail
mm: kmemleak: scan the struct page array in MAX_SCAN_SIZE batches
mm: kmemleak: move the struct page scan into a helper
mm/damon: document that a zero sample_interval is accepted
mm/damon: fix typos in comments
mm/damon/sysfs: propagate damon_call() error in turn_damon_on
mm/damon/core: skip quota score setup when the quota is full
mm/damon/tests/core-kunit: test the size charged for a filter-trimmed region
mm/damon/core: charge only the part of a region the filter left
mm: disallow raw PFN mappings of huge/shared zeropage
selftests/mm: zap whole PTE tables in the khugepaged race harness
selftests/mm: add memory-pressure threads to the khugepaged race harness
selftests/mm: race the collapse of windows with holes
selftests/mm: add khugepaged race harness
selftests/mm: check that one khugepaged pass collapses one window
selftests/mm: run every supported collapse order by default
selftests/mm: cover a shared-source collapse write race
selftests/mm: parameterize the mixed-source collapse case by source order
selftests/mm: add order-parameterized khugepaged collapse cases
...

powerpc/numa: Support coregroup on PowerNV

2026-10-12T05:54:19+00:00

Coregroup support on powerpc has so far been limited to PowerVM LPARs.
However, PowerNV can also support coregroups when firmware exposes the
required coregroup information through the associativity hierarchy.

Detect coregroup support by checking whether primary_domain_index is the
penultimate domain in the CPU node's ibm,associativity property. On
PowerNV, a non-penultimate primary_domain_index indicates that firmware
provides an additional level for coregroup information.

This keeps the logic compatible with PowerVM systems, where
primary_domain_index is likewise not the penultimate associativity
domain.

Signed-off-by: Srikar Dronamraju 
Reviewed-by: Shrikanth Hegde 
Signed-off-by: Madhavan Srinivasan 
Link: https://patch.msgid.link/20260902123458.340456-8-srikar@linux.ibm.com

powerpc/numa: Allow cpu_to_coregroup_id without PPC_SPLPAR

2026-10-12T05:54:19+00:00

Make cpu_to_coregroup_id() available outside PPC_SPLPAR so it can be
used by platforms that do not rely on the SPLPAR-specific VPHN path.

Keep the existing fallback behavior by returning the core ID when
coregroup information is unavailable.

Signed-off-by: Srikar Dronamraju 
Reviewed-by: Shrikanth Hegde 
Signed-off-by: Madhavan Srinivasan 
Link: https://patch.msgid.link/20260902123458.340456-7-srikar@linux.ibm.com

powerpc/numa: Simplify find_primary_domain_index

2026-10-12T05:54:19+00:00

Initialize the return value once and use a single exit path in
find_primary_domain_index().

This is a small cleanup that keeps the existing behavior unchanged while
making the control flow easier to follow.

Signed-off-by: Srikar Dronamraju 
Reviewed-by: Shrikanth Hegde 
Reviewed-by: Ritesh Harjani (IBM) 
Signed-off-by: Madhavan Srinivasan 
Link: https://patch.msgid.link/20260902123458.340456-6-srikar@linux.ibm.com

mm/sparse-vmemmap: drop the extra tail page from device DAX reservation

2026-10-09T05:55:08+00:00

The device DAX vmemmap population still reserves one extra tail vmemmap
page after the head page.

Drop that extra reservation and let the shared tail page cover all tail
vmemmap pages after the head page, so DAX follows the same reservation
model as HugeTLB.

This reduces the reserved vmemmap pages for optimized DAX mappings to one
and removes the now-unneeded first-tail population from the generic and
powerpc paths to simplify the code as well.

Link: https://lore.kernel.org/20260930140627.57431-11-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Signed-off-by: Andrew Morton 
Acked-by: Qi Zheng 
Acked-by: David Hildenbrand (Arm) 
Cc: Oscar Salvador 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Jonathan Corbet 
Cc: Lorenzo Stoakes 
Cc: Mike Rapoport 
Cc: Nicholas Piggin 
Cc: Christophe Leroy 
Cc: Ritesh Harjani (IBM) 
Cc: Shrikanth Hegde 
Cc: Randy Dunlap 
Cc: Lance Yang

powerpc/mm: switch device DAX to shared tail vmemmap pages

2026-10-09T05:55:07+00:00

The powerpc radix compound vmemmap population path still finds a reusable
tail page by walking the vmemmap page tables.

Switch it to the common vmemmap_shared_tail_page() helper instead, so it
can use the shared vmemmap page directly to simplify the code.

This removes the powerpc-specific tail-page lookup and its fallback path
and aligns the device DAX vmemmap optimization path with HugeTLB.

[muchun.song@linux.dev: use try_get_page()]
  Link: https://lore.kernel.org/20260930152826.76084-1-songmuchun@bytedance.com
Link: https://lore.kernel.org/20260930140627.57431-10-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Signed-off-by: Andrew Morton 
Acked-by: David Hildenbrand (Arm) 
Cc: Oscar Salvador 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Jonathan Corbet 
Cc: Lorenzo Stoakes 
Cc: Mike Rapoport 
Cc: Qi Zheng 
Cc: Nicholas Piggin 
Cc: Christophe Leroy 
Cc: Ritesh Harjani (IBM) 
Cc: Shrikanth Hegde 
Cc: Randy Dunlap 
Cc: Lance Yang