Merge drm/drm-fixes into drm-misc-fixes

Getting fixes and updates from v7.1-rc1.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge branch 'next' into for-linus

Prepare input updates for 7.1 merge window.

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
...

show more ...

mm/page_idle.c: remove redundant mmu notifier in aging code

Now we have mmu_notifier_clear_young immediately follows
pmdp_clear_young_notify which internally calls mmu_notifier_clear_young,
this is

mm/page_idle.c: remove redundant mmu notifier in aging code

Now we have mmu_notifier_clear_young immediately follows
pmdp_clear_young_notify which internally calls mmu_notifier_clear_young,
this is redundant. change it with non-notify variant and keep consistent
with ptep aging code.

Link: https://lkml.kernel.org/r/20260203102649.2486836-1-qin.yuA@h3c.com
Signed-off-by: qinyu <qin.yuA@h3c.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Acked-by: David Hildenbrand (arm) <david@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

Merge tag 'v7.0-rc3' into next

Sync up with the mainline to brig up the latest changes, specifically
changes to ALPS driver.

Merge branch 'for-6.20/sony' into for-linus

- Support for Rock band 4 PS4 and PS5 guitars (Rosalie Wanders)

Merge tag 'v6.19-rc1' into msm-next

Merge Linux 6.19-rc1 in order to catch up with other changes (e.g. UBWC
config database defining UBWC_6).

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.q

Merge tag 'v6.19-rc1' into msm-next

Merge Linux 6.19-rc1 in order to catch up with other changes (e.g. UBWC
config database defining UBWC_6).

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

show more ...

Merge tag 'asoc-fix-v6.19-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v6.19

We've been quite busy with fixes since the merge window, though

Merge tag 'asoc-fix-v6.19-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v6.19

We've been quite busy with fixes since the merge window, though not in
any particularly exciting ways - the standout thing is the fix for _SX
controls which were broken by a change to how we do clamping, otherwise
it's all fairly run of the mill fixes and quirks.

show more ...

Merge drm/drm-next into drm-xe-next

Backmerging to bring in 6.19-rc1. An important upstream bugfix and
to help unblock PTL CI.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf after 6.19-rc1

Cross-merge BPF and other fixes after downstream PR.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Merge drm/drm-next into drm-intel-next

Sync-up some display code needed for Async flips refactor.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Merge remote-tracking branch 'drm/drm-fixes' into drm-misc-fixes

Pull in rc1 to include all changes since the merge window closed,
and grab all fixes and changes from drm/drm-next.

Signed-off-by: M

Merge remote-tracking branch 'drm/drm-fixes' into drm-misc-fixes

Pull in rc1 to include all changes since the merge window closed,
and grab all fixes and changes from drm/drm-next.

Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>

show more ...

Merge drm/drm-next into drm-misc-next

Let's kickstart the v6.20 (7.0?) release cycle.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

"__vmalloc()/kvmalloc() and no-block support" (Uladzislau Rezki

Merge tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

"__vmalloc()/kvmalloc() and no-block support" (Uladzislau Rezki)
Rework the vmalloc() code to support non-blocking allocations
(GFP_ATOIC, GFP_NOWAIT)

"ksm: fix exec/fork inheritance" (xu xin)
Fix a rare case where the KSM MMF_VM_MERGE_ANY prctl state is not
inherited across fork/exec

"mm/zswap: misc cleanup of code and documentations" (SeongJae Park)
Some light maintenance work on the zswap code

"mm/page_owner: add debugfs files 'show_handles' and 'show_stacks_handles'" (Mauricio Faria de Oliveira)
Enhance the /sys/kernel/debug/page_owner debug feature by adding
unique identifiers to differentiate the various stack traces so
that userspace monitoring tools can better match stack traces over
time

"mm/page_alloc: pcp->batch cleanups" (Joshua Hahn)
Minor alterations to the page allocator's per-cpu-pages feature

"Improve UFFDIO_MOVE scalability by removing anon_vma lock" (Lokesh Gidra)
Address a scalability issue in userfaultfd's UFFDIO_MOVE operation

"kasan: cleanups for kasan_enabled() checks" (Sabyrzhan Tasbolatov)

"drivers/base/node: fold node register and unregister functions" (Donet Tom)
Clean up the NUMA node handling code a little

"mm: some optimizations for prot numa" (Kefeng Wang)
Cleanups and small optimizations to the NUMA allocation hinting
code

"mm/page_alloc: Batch callers of free_pcppages_bulk" (Joshua Hahn)
Address long lock hold times at boot on large machines. These were
causing (harmless) softlockup warnings

"optimize the logic for handling dirty file folios during reclaim" (Baolin Wang)
Remove some now-unnecessary work from page reclaim

"mm/damon: allow DAMOS auto-tuned for per-memcg per-node memory usage" (SeongJae Park)
Enhance the DAMOS auto-tuning feature

"mm/damon: fixes for address alignment issues in DAMON_LRU_SORT and DAMON_RECLAIM" (Quanmin Yan)
Fix DAMON_LRU_SORT and DAMON_RECLAIM with certain userspace
configuration

"expand mmap_prepare functionality, port more users" (Lorenzo Stoakes)
Enhance the new(ish) file_operations.mmap_prepare() method and port
additional callsites from the old ->mmap() over to ->mmap_prepare()

"Fix stale IOTLB entries for kernel address space" (Lu Baolu)
Fix a bug (and possible security issue on non-x86) in the IOMMU
code. In some situations the IOMMU could be left hanging onto a
stale kernel pagetable entry

"mm/huge_memory: cleanup __split_unmapped_folio()" (Wei Yang)
Clean up and optimize the folio splitting code

"mm, swap: misc cleanup and bugfix" (Kairui Song)
Some cleanups and a minor fix in the swap discard code

"mm/damon: misc documentation fixups" (SeongJae Park)

"mm/damon: support pin-point targets removal" (SeongJae Park)
Permit userspace to remove a specific monitoring target in the
middle of the current targets list

"mm: MISC follow-up patches for linux/pgalloc.h" (Harry Yoo)
A couple of cleanups related to mm header file inclusion

"mm/swapfile.c: select swap devices of default priority round robin" (Baoquan He)
improve the selection of swap devices for NUMA machines

"mm: Convert memory block states (MEM_*) macros to enums" (Israel Batista)
Change the memory block labels from macros to enums so they will
appear in kernel debug info

"ksm: perform a range-walk to jump over holes in break_ksm" (Pedro Demarchi Gomes)
Address an inefficiency when KSM unmerges an address range

"mm/damon/tests: fix memory bugs in kunit tests" (SeongJae Park)
Fix leaks and unhandled malloc() failures in DAMON userspace unit
tests

"some cleanups for pageout()" (Baolin Wang)
Clean up a couple of minor things in the page scanner's
writeback-for-eviction code

"mm/hugetlb: refactor sysfs/sysctl interfaces" (Hui Zhu)
Move hugetlb's sysfs/sysctl handling code into a new file

"introduce VM_MAYBE_GUARD and make it sticky" (Lorenzo Stoakes)
Make the VMA guard regions available in /proc/pid/smaps and
improves the mergeability of guarded VMAs

"mm: perform guard region install/remove under VMA lock" (Lorenzo Stoakes)
Reduce mmap lock contention for callers performing VMA guard region
operations

"vma_start_write_killable" (Matthew Wilcox)
Start work on permitting applications to be killed when they are
waiting on a read_lock on the VMA lock

"mm/damon/tests: add more tests for online parameters commit" (SeongJae Park)
Add additional userspace testing of DAMON's "commit" feature

"mm/damon: misc cleanups" (SeongJae Park)

"make VM_SOFTDIRTY a sticky VMA flag" (Lorenzo Stoakes)
Address the possible loss of a VMA's VM_SOFTDIRTY flag when that
VMA is merged with another

"mm: support device-private THP" (Balbir Singh)
Introduce support for Transparent Huge Page (THP) migration in zone
device-private memory

"Optimize folio split in memory failure" (Zi Yan)

"mm/huge_memory: Define split_type and consolidate split support checks" (Wei Yang)
Some more cleanups in the folio splitting code

"mm: remove is_swap_[pte, pmd]() + non-swap entries, introduce leaf entries" (Lorenzo Stoakes)
Clean up our handling of pagetable leaf entries by introducing the
concept of 'software leaf entries', of type softleaf_t

"reparent the THP split queue" (Muchun Song)
Reparent the THP split queue to its parent memcg. This is in
preparation for addressing the long-standing "dying memcg" problem,
wherein dead memcg's linger for too long, consuming memory
resources

"unify PMD scan results and remove redundant cleanup" (Wei Yang)
A little cleanup in the hugepage collapse code

"zram: introduce writeback bio batching" (Sergey Senozhatsky)
Improve zram writeback efficiency by introducing batched bio
writeback support

"memcg: cleanup the memcg stats interfaces" (Shakeel Butt)
Clean up our handling of the interrupt safety of some memcg stats

"make vmalloc gfp flags usage more apparent" (Vishal Moola)
Clean up vmalloc's handling of incoming GFP flags

"mm: Add soft-dirty and uffd-wp support for RISC-V" (Chunyan Zhang)
Teach soft dirty and userfaultfd write protect tracking to use
RISC-V's Svrsw60t59b extension

"mm: swap: small fixes and comment cleanups" (Youngjun Park)
Fix a small bug and clean up some of the swap code

"initial work on making VMA flags a bitmap" (Lorenzo Stoakes)
Start work on converting the vma struct's flags to a bitmap, so we
stop running out of them, especially on 32-bit

"mm/swapfile: fix and cleanup swap list iterations" (Youngjun Park)
Address a possible bug in the swap discard code and clean things
up a little

[ This merge also reverts commit ebb9aeb980e5 ("vfio/nvgrace-gpu:
register device memory for poison handling") because it looks
broken to me, I've asked for clarification - Linus ]

* tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
mm: fix vma_start_write_killable() signal handling
mm/swapfile: use plist_for_each_entry in __folio_throttle_swaprate
mm/swapfile: fix list iteration when next node is removed during discard
fs/proc/task_mmu.c: fix make_uffd_wp_huge_pte() huge pte handling
mm/kfence: add reboot notifier to disable KFENCE on shutdown
memcg: remove inc/dec_lruvec_kmem_state helpers
selftests/mm/uffd: initialize char variable to Null
mm: fix DEBUG_RODATA_TEST indentation in Kconfig
mm: introduce VMA flags bitmap type
tools/testing/vma: eliminate dependency on vma->__vm_flags
mm: simplify and rename mm flags function for clarity
mm: declare VMA flags by bit
zram: fix a spelling mistake
mm/page_alloc: optimize lowmem_reserve max lookup using its semantic monotonicity
mm/vmscan: skip increasing kswapd_failures when reclaim was boosted
pagemap: update BUDDY flag documentation
mm: swap: remove scan_swap_map_slots() references from comments
mm: swap: change swap_alloc_slow() to void
mm, swap: remove redundant comment for read_swap_cache_async
mm, swap: use SWP_SOLIDSTATE to determine if swap is rotational
...

show more ...

mm/rmap: extend rmap and migration support device-private entries

Add device-private THP support to reverse mapping infrastructure, enabling
proper handling during migration and walk operations.

Th

mm/rmap: extend rmap and migration support device-private entries

Add device-private THP support to reverse mapping infrastructure, enabling
proper handling during migration and walk operations.

The key changes are:
- add_migration_pmd()/remove_migration_pmd(): Handle device-private
entries during folio migration and splitting
- page_vma_mapped_walk(): Recognize device-private THP entries during
VMA traversal operations

This change supports folio splitting and migration operations on
device-private entries.

[balbirs@nvidia.com: fix override of entry in remove_migration_pmd]
Link: https://lkml.kernel.org/r/20251114012153.2634497-2-balbirs@nvidia.com
[balbirs@nvidia.com: follow pattern used in remove_migration_pte()]
Link: https://lkml.kernel.org/r/20251115002835.3515194-1-balbirs@nvidia.com
Link: https://lkml.kernel.org/r/20251001065707.920170-5-balbirs@nvidia.com
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm: always call rmap_walk() on locked folios

Patch series "Improve UFFDIO_MOVE scalability by removing anon_vma lock", v2.

Userfaultfd has a scalability issue in its UFFDIO_MOVE ioctl, which is
hea

mm: always call rmap_walk() on locked folios

Patch series "Improve UFFDIO_MOVE scalability by removing anon_vma lock", v2.

Userfaultfd has a scalability issue in its UFFDIO_MOVE ioctl, which is
heavily used in Android as its java garbage collector uses it for
concurrent heap compaction.

The issue arises because UFFDIO_MOVE updates folio->mapping to an anon_vma
with a different root, in order to move the folio from a src VMA to dst
VMA. It performs the operation with the folio locked, but this is
insufficient, because rmap_walk() can be performed on non-KSM anonymous
folios without folio lock.

This means that UFFDIO_MOVE has to acquire the anon_vma write lock of the
root anon_vma belonging to the folio it wishes to move.

This causes scalability bottleneck when multiple threads perform
UFFDIO_MOVE simultanously on distinct pages of the same src VMA. In field
traces of arm64 android devices, we have observed janky user interactions
due to long (sometimes over ~50ms) uninterruptible sleeps on main UI
thread caused by anon_vma lock contention in UFFDIO_MOVE. This is
particularly severe during the beginning of GC's compaction phase when it
is likely to have multiple threads involved.

This patch resolves the issue by removing the exception in rmap_walk() for
non-KSM anon folios by ensuring that all folios are locked during rmap
walk. This is less problematic than it might seem, as the only major
caller which utilises this mode is shrink_active_list(), which is covered
in detail in the first patch of this series.

As a result of changing our approach to locking, we can remove all the
code that took steps to acquire an anon_vma write lock instead of a folio
lock. This results in a significant simplification and scalability
improvement of the code (currently only in UFFDIO_MOVE). Furthermore, as
a side-effect, folio_lock_anon_vma_read() gets simpler as we don't need to
worry that folio->mapping may have changed under us.


This patch (of 2):

Guarantee that rmap_walk() is called on locked folios so that threads
changing folio->mapping and folio->index for non-KSM anon folios can
serialize on fine-grained folio lock rather than anon_vma lock. Other
folio types are already always locked before rmap_walk(). With this, we
are going from 'not necessarily' locking the non-KSM anon folio to
'definitely' locking it during rmap walks.

This patch is in preparation for removing anon_vma write-lock from
UFFDIO_MOVE.

With this patch, three functions are now expected to be called with a
locked folio. To be careful of not missing any case, here is the
exhaustive list of all their callers.

1) rmap_walk() is called from:

a) folio_referenced()
b) damon_folio_mkold()
c) damon_folio_young()
d) page_idle_clear_pte_refs()
e) try_to_unmap()
f) try_to_migrate()
g) folio_mkclean()
h) remove_migration_ptes()

In the above list, first 4 are changed in this patch to try-lock non-KSM
anon folios, similar to other types of folios. The remaining functions in
the list already hold folio lock when calling rmap_walk().

2) folio_lock_anon_vma_read() is called from following functions:

a) collect_procs_anon()
b) page_idle_clear_pte_refs()
c) damon_folio_mkold()
d) damon_folio_young()
e) folio_referenced()
f) try_to_unmap()
g) try_to_migrate()

All the functions in above list, except collect_procs_anon(), are covered
by the rmap_walk() list above. For collect_procs_anon(), with
kill_procs_now() changed to take folio lock in this patch ensures that all
callers of folio_lock_anon_vma_read() now hold the lock.

3) folio_get_anon_vma() is called from following functions, all of which
already hold the folio lock:

a) move_pages_huge_pmd()
b) __folio_split()
c) move_pages_ptes()
d) migrate_folio_unmap()
e) unmap_and_move_huge_page()

Functionally, this patch doesn't break the logic because rmap walkers
generally do some other check to see if what is expected to mapped did
happen so it's fine, or otherwise treat things as best-effort.

Among the 4 functions changed in this patch, folio_referenced() is the
only core-mm function, and is also frequently accessed. To assess the
impact of locking non-KSM anon folios in
shrink_active_list()->folio_referenced() path, we performed an app cycle
test on an arm64 android device. During the whole duration of the test
there were over 140k invocations of shrink_active_list(), out of which
over 29k had at least one non-KSM anon folio on which folio_referenced()
was called. In none of these invocations folio_trylock() failed.

Of course, we now take a lock where we wouldn't previously have. In the
past it would have had a major impact in causing a CoW write fault to copy
a page in do_wp_page(), as commit 09854ba94c6a ("mm: do_wp_page()
simplification") caused a failure to obtain folio lock to result in a page
copy even if one wasn't necessary.

However, since commit 6c287605fd56 ("mm: remember exclusively mapped
anonymous pages with PG_anon_exclusive"), and the introduction of the
folio anon exclusive flag, this issue is significantly mitigated.

The only case remaining that we might worry about from this perspective is
that of read-only folios immediately after fork where the anon exclusive
bit will not have been set yet.

We note however in the case of read-only just-forked folios that
wp_can_reuse_anon_folio() will notice the raised reference count
established by shrink_active_list() via isolate_lru_folios() and refuse to
reuse in any case, so this will in fact have no impact - the folio lock is
ultimately immaterial here.

All-in-all it appears that there is little opportunity for meaningful
negative impact from this change.

Link: https://lkml.kernel.org/r/20250923071019.775806-1-lokeshgidra@google.com
Link: https://lkml.kernel.org/r/20250923071019.775806-2-lokeshgidra@google.com
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Barry Song <baohua@kernel.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Nicolas Geoffray <ngeoffray@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

Merge remote-tracking branch 'drm/drm-next' into msm-next-robclark

Back-merge drm-next to get caught up.

Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>

Merge branch 'next' into for-linus

Prepare input updates for 6.18 merge window.

Merge drm/drm-next into drm-intel-gt-next

Backmerge in order to get the commit:

048832a3f400 ("drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter")

To drm-intel-gt-next as there are f

Merge drm/drm-next into drm-intel-gt-next

Backmerge in order to get the commit:

048832a3f400 ("drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter")

To drm-intel-gt-next as there are followup fixes to be applied.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

show more ...

Merge drm/drm-next into drm-misc-next-fixes

Backmerging to drm-misc-next-fixes to get features and fixes from
v6.17-rc6.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-next into drm-intel-next

Catching up with some display dependencies.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Merge tag 'v6.17-rc2' into HEAD

Sync up with mainline to bring in changes to include/linux/sprintf.h

Merge drm/drm-next into drm-xe-next

Bring v6.17-rc1 to propagate commits from other subsystems, particularly
PCI, which has some new functions needed for SR-IOV integration.

Signed-off-by: Lucas De

Merge drm/drm-next into drm-xe-next

Bring v6.17-rc1 to propagate commits from other subsystems, particularly
PCI, which has some new functions needed for SR-IOV integration.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

show more ...

Merge drm/drm-fixes into drm-misc-fixes

Updating drm-misc-fixes to the state of v6.17-rc1. Begins a new release
cycle.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Merge drm/drm-next into drm-misc-n

Updating drm-misc-next to the state of v6.17-rc1. Begins a new release
cycle.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>