kernel/git/stable/linux.git/fs/dax.c, branch master

Merge tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-08-21T01:17:08+00:00

Pull MM updates from Andrew Morton: - "mm: drop "sub" prefix from various places" (Dev Jain) page->folio conversion and a naming cleanup - "mm/kasan: remove redundant initialization for kasan_flag_write_only" (Igor Putko) KASAN cleanup work - "mm/filemap: reduce unnecessary xarray lookups" (Chi Zhiling) Small speedup in the pagecaache read code - "mm/percpu: Fix possible NOFS/NOIO reclaim recursion" (Kaitao Cheng) Improve the vmalloc code - mainly the avoidance of GFP_KERNEL allocations when the caller asked for GFP_NOFS or GFP_NOIO - "mm/kmemleak: avoid soft lockup when scanning task stacks" (Breno Leitao) Avoid a soft lockup watchdog trigger from the kmemleak scanning code in extreme situations - "mm/page_owner: misc cleanups" (Ye Liu) Cleanups to the page_owner code. For some reason lots of people have been working on the page_owner code this cycle. - "mm: convert to walk_page_range_vma() to eliminate find_vma()" (Kefeng Wang) Simplify and accelerate the page walking library function - "mm/migrate: preparatory cleanups for batch copy and offload" (Shivank Garg) Cleanups in the migration code - "mm/page_owner: add per-fd filter infrastructure for print_mode and NUMA filtering" (Zhen Ni) Per-fd filtering to page_owner in order to reduce the sometimes vast amount of output it can produce - "mm: Refactor bootmem gigantic hugepage allocation" (Muchun Song) Fixes and preparatory cleanups around bootmem HugeTLB handling, sparse initialization ordering, and related vmemmap setup - "mm/zsmalloc: reduce lock contention in zs_free()" (Wenchao Hao) Reduce lock contention in zs_free(), which dominates the unmap path under memory pressure on Android (LMK kills) and on x86 servers running zswap-heavy workloads. Up to 1.83x improvement in microbenchmarking. - "move alloc_tag.c file under mm/" (Suren Baghdasaryan) - "samples/damon: handle damon_{start,stop}() failures" (SJ Park) Fix improper handling of damon_start(), damon_stop(), and damon_call() failures across DAMON sample modules to prevent potential memory leaks, operation disruptions and use-after-free bugs - "mm/damon/sysfs: kobject_del() directories that users can create/remove" (SJ Park) Fix delayed sysfs directory removal under DEBUG_KOBJECT_RELEASE causeing creation failures due to duplicate directory names by adding missing kobject_del() calls before creating new directories - "mm: cleanup clear_not_present_full_ptes()" (David Hildenbrand) Clean up the core pte handling code - "selftests/damon: misc fixes for test bugs" (Kunwu Chan) Fix several bugs in the DAMON selftests - "selftests/damon: fix memcg_path staging handling" (Cheng Nie) Fix a bug in _damon_sysfs.py for damos_filter memcg_path setup, and add a test case for it in sysfs.py. - "selftests/damon: test kdamond refresh_ms" (Ruslan Valiyev) Selftest coverage for DAMON's refresh_ms sysfs feature by updating the test control module and verifying that scheme stats update automatically without manual intervention - "mm/damon: five misc fixups" (Akinobu Mita) Miscellaneous DAMON fixups. - "mm/damon/core: detect internal variation above max_nr_regions/2" (Jiayuan Chen) Fix DAMON's region splitting behavior when region counts exceed half the maximum budget by dynamically scaling down the split fraction as the limit approaches, preventing large regions from staying un-split, and add corresponding KUnit test coverage - "mm: preparatory patches for PMD level swap entries" (Usama Arif) Refactor and clean up PMD softleaf helpers, call sites, and architecture flags to lay the groundwork for a follow-up series that introduces PMD page table swap entries - "mm/damon: update, optimize, and clean up doc, tests, and code" (SJ Park) Update DAMON design and ABI documentation, expands unit and selftest coverage, optimize damon_commit_target_regions(), and clean up recently added sysfs interface code for better readability - "mm/vmpressure: reduce CPU, memory and code overhead on cgroup v2" (Usama Arif) Optimize vmpressure() by skipping unnecessary work on cgroup v2 for userspace event notifications and refactor v1-only eventfd handling into mm/memcontrol-v1.c to reduce memory overhead and code complexity - "selftests/mm: refactor pkey helpers and fix mmap error handling" (Hongfu Li) Refactor pkeys shared tracing and assertion helpers into a common file, unify protection key selftests to use consistent diagnostic logging and assertions, and enforce standardized MAP_FAILED return checks for mmap() calls across the tests - "mm/damon: optimize out nr_accesses_bp" (SJ Park) Replace the error-prone, continuously updated nr_accesses_bp field in damon_region with an on-demand moving sum function, reducing structure memory overhead and avoiding state corruption bugs - "Open HugeTLB allocation routine for more generic use" (Ackerley Tng) Decouple HugeTLB folio allocation from VMA dependencies by introducing hugetlb_alloc_folio(), enabling subsystems like guest_memfd to allocate HugeTLB folios without standard VMA reservations or pseudo-VMAs - "mm/damon: provide pseudo moving sum probe_hits" (SJ Park) Integrate DAMON's probe_hits attribute counter into the pseudo moving sum infrastructure, enabling real-time, online monitoring without waiting for full aggregation intervals - "mm: Some cleanups for page allocator APIs" (Brendan Jackman) Simplify and refactor the page allocator entry points and flags by unifying allocation paths, adding internal alloc_flags arguments, and eliminating redundant __ prefixed alloc_pages variants. - "Fix incorrect access of hugetlb pte entries" (Dev Jain) Enforce the consistent use of huge_ptep_get() instead of ptep_get() for HugeTLB entries and fixes an unaligned address issue in arm64's huge_ptep_get() implementation - "mm/damon: validate all parameters in the core" (SJ Park) Consolidate parameter validation into the DAMON core specifically within damon_start() and damon_commit_ctx() to centralize error checking, eliminate caller-side redundant checks and to improve maintenance efficiency - "tools/mm/page_owner_sort: fix filtering and cleanup issues" (Yichong Chen) Rename is_need() to filter_record() for clearer return semantics, fix per-record allocation memory leaks and bound output copies in search_pattern() to address an existing buffer issue - "memcg: bail out reclaim when memcg is dying" (Jiayuan Chen) Mitigate a system-wide stall which occurs when a cgroup is removed while one of its memory control files is doing synchronous reclaim - "mm/memory-failure: add panic option for unrecoverable pages" (Breno Leitao) Introduce an opt-in vm.panic_on_unrecoverable_memory_failure sysctl that immediately panics the kernel on unrecoverable memory errors in kernel-owned pages to preserve error context and prevent delayed, silent data corruption - "mm/damon: refactor damon_{start,stop,commit}() for simple error handling" (SJ Park) Refactor the DAMON core API functions to guarantee that all contexts are fully stopped when damon_start(), damon_stop(), or damon_commit() fail, eliminating the need for complex and error-prone caller-side cleanup code - "Keep tail page private zero at free and folio split" (Zi Yan) Add checks to ensure tail_page->private is zero when freeing compound or high-order pages and when promoting tail pages during large folio splits. By validating these fields at free and split time, it allows the removal of redundant private field clearing inside prep_compound_tail() - "mm: drop redundant lru_add_drain in anon folio reuse paths" (Barry Song) Eliminate redundant lru_add_drain() calls in wp_can_reuse_anon_folio() and do_swap_page() to reduce LRU lock contention and system overhead By validating folio refcounts against the LRU cache before draining and removing unnecessary drains in the swap path, it achieves up to a 30.5% reduction in drain calls during heavy swap workloads - "mm: clean up folio LRU and swap declarations" (Jianyue Wu) Reorganize folio LRU and swap code by relocating page-cluster state to mm/swap_state.c, renaming mm/swap.c to mm/folio.c, and moving MM-internal reclaim declarations into mm/internal.h. - "userfaultfd: working set tracking for VM guest memory" (Kiryl Shutsemau) Add userfaultfd support for tracking the working set of VM guest memory, so a VMM can identify hot pages and reclaim cold ones to tiered or remote storage - "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 2)" (David Hildenbrand) Remove the remaining pieces of CONFIG_HAVE_BOOTMEM_INFO_NODE, performing some smaller cleanups around freeing of reserved vmemmap pages on the way. - "mm/damon: update probe hits for runtime parameter commits" (SJ Park) Ensure that DAMON's probe_hits attribute counter is properly updated when monitoring intervals are changed at runtime, matching the behavior of nr_accesses. To achieve this, it refactors and renames existing helper functions for shared use, applies the updates to probe_hits, and handles edge cases in damon_probe_hits_mvsum() to maintain measurement accuracy. - "KSM: performance optimizations for rmap_walk_ksm" (xu xin) Resolve a severe KSM reverse-mapping performance bottleneck where thousands of split VMAs sharing a single anon_vma cause extended lock contention. By adding an interval-filtering check during the rmap walk, it reduces worst-case anon_vma lock hold times from over 500ms down to under 2ms, preventing application freezes and latency spikes under memory pressure. - "mm: split a couple of headers from internal.h" (Mike Rapoport) Split declarations related to mm_init, memblock, vmalloc and sparse into new headers - "KSM: use linear_page_index in collect_procs_ksm()" (xu xin) Apply the interval tree optimization from rmap_walk_ksm() to collect_procs_ksm() to avoid iterating over non-matching VMAs during KSM memory error handling. It hoists loop-invariant address initialization and restricts the anon_vma_interval_tree_foreach walk to a targeted page offset range, reducing redundant checks and improving lookup efficiency. - "selftests/mm: avoid false failures in hugetlb and KSM tests" (Sayali Patil) Fix issues in the hugetlb and KSM MM selftest categories that can report failures when the prerequisites for the tests are not satisfied - "mm/damon: introduce data attributes only monitoring" (SJ Park) Introduce attribute-weighted region management in DAMON, allowing users to prioritize specific data attributes (such as page sizes or cgroups) over or instead of access monitoring. By assigning weights to attribute probes, DAMON can completely disable access tracking and adjust monitoring regions based on weighted probe-hit counters to optimize monitoring quality for attribute-focused workloads. - "mm/hmm: Add mmap lock-drop support for userfaultfd-backed mappings" (Stanislav Kinsburskii) Extend hmm_range_fault() to support userfaultfd-backed regions by allowing the mmap lock to be dropped during fault handling via a new hmm_range_fault_locked() helper. By accepting a locked pointer and signaling retry status when lock release occurs, it enables page fault resolution in userfaultfd regions while preserving backward compatibility for existing callers. - "mm: make VMA page offset handling more consistent" (Lorenzo Stoakes) Clean up and standardize how vma->vm_pgoff is accessed and manipulated across file-backed and anonymous mappings in the kernel It introduces dedicated helper functions such as vma_start_pgoff(), vma_end_pgoff(), vma_set_pgoff() and linear_page_delta() while renaming rmap interval tree helpers to better reflect their functionality. These changes establish a cleaner foundation for future work that will unify virtual page offset indexing for all anonymous and CoW'd folios. - "mm: handle device-private PMDs in walk callbacks" (Usama Arif) Address kernel panics and state corruption caused by MM walk callbacks reaching non-present device-private PMD swap entries created during HMM migrations It ensures that functions which acquire pmd_trans_huge_lock() properly recognize device-private PMDs instead of assuming a present THP or a standard migration entry. - "mm/rmap: Refactor try_to_unmap_one" (Dev Jain) Refactor try_to_unmap_one by modularizing Hugetlb, anonymous-lazyfree, and anonymous-swapbacked logic into dedicated functions, laying the structural groundwork for batched anonymous large folio unmapping. - "Docs/ABI/damon: sysfs ABI document fixes and additions" (Song Hu) Fix typos and fills in missing entries in the DAMON sysfs ABI document - "dax/kmem: atomic whole-device hotplug via sysfs" (Gregory Price) Introduce an atomic sysfs state attribute and supporting DAX/MM infrastructure to prevent userland races when offlining and removing entire memory regions By adding an unplugged state alongside standard online modes, it enables whole-device atomic hotplug control while preserving backward compatibility. - "mm: convert more vm_flags_t users to vma_flags_t" (Lorenzo Stoakes) Continue transitioning the kernel from the deprecated vm_flags_t type to vma_flags_t across core memory management infrastructure. It replaces legacy type usage in core functions such as do_mmap(), unmapped area allocation, mm->def_vma_flags, and VMA operations like mlock, mprotect, and mremap. - "Two small patches to clean up mm/mm_slot.h" (xu xin) Refactor mm_slot.h by introducing mm_slot_remove() to unify duplicate slot deletion sequences in khugepaged and KSM. It also adds code documentation explaining why mm_slot_lookup and mm_slot_insert must remain as preprocessor macros rather than static inline functions. - "mm/damon/core: hide core-private struct fields" (SJ Park) Clean up DAMON core structures by consistently marking internal-only fields with private: comment tags to prevent improper direct access from outer layers. It enforces encapsulation across core structures including damon_region, damon_target, and damon_ctx and updates DAMON_SYSFS to interact through approved access APIs instead of exposing raw struct members. - "mm/damon: unurgent fixes for infinite loop, NULL de-ref and races" (SJ Park) Address potential infinite loops, NULL dereferences, and race conditions identified in DAMON It fixes an infinite loop triggered by extreme user configurations, a NULL pointer dereference within unit tests and minor monitoring accuracy degradation caused by subtle runtime races. - "mm/page_alloc: fixes for free_pages_nolock() on RT/UP" (Brendan Jackman) Fix an NMI safety flaw in __free_frozen_pages() where freeing pages on non-SMP or PREEMPT_RT kernels can bypass can_spin_trylock() checks via non-PCP or isolated migration paths. It also resolves potential kernel crashes and privilege escalation risks triggered when BPF tracing runs in NMI context alongside memory hotplug or large allocation frees. - "mm/page_alloc: couple of followups for recent cleanups" (Brendan Jackman) Clean up and update page allocator nomenclature, documentation, and debug assertions. It aligns internal FPI_ flags with the public "nolock" naming convention, removes outdated internal implementation details from high-level page allocator comments, and eliminates obsolete VM_BUG_ON() assertions in allocation paths. - "mm/mseal: further cleanups" (Lorenzo Stoakes) Refactor and simplify the mseal implementation by clarifying API boundaries and removing unnecessary code complexity. It replaces generic do_mseal() usage outside the syscall with a dedicated mseal_mmap_page_zero() helper for MMAP_PAGE_ZERO, eliminates mm_struct parameters to enforce that sealing applies only to current->mm, and streamlines overall logic and comments with no functional changes intended. - "mm/vmscan: fix swappiness=max and clean up per-node proactive reclaim" (Ridong Chen) Resolve reclaim behavior bugs and clean up function parameters across memory reclaim paths It fixes swappiness=max in both standard reclaim and MGLRU so unswappable anonymous memory no longer falls back to evicting page cache, ensures reclaim_store() returns accurate error codes instead of collapsing all failures into -EAGAIN, and removes the obsolete gfp_mask parameter from __node_reclaim(). - "mm: mincore: misc cleanups" (Kefeng Wang) Clean up and simplifies the mincore code. Most importantly, it removes the historical special behavior that always reports VM_PFNMAP pages as non-resident. - "mm/huge_memory: drop dead split helper variants" (Kiryl Shutsemau) Two trivial cleanups in the folio split API - "mm/damon: fix uninitialized DAMOS field and kunit exec expectation bugs" (SJ Park) Resolve minor operational and testing bugs in DAMON identified by Sashiko. It initializes the damos->last_applied field to prevent occasional efficiency degradation and fixes invalid memory accesses in DAMON KUnit tests during test failure handling. - "cleanup for stable_page_flags()" (Jinjiang Tu) Clean up and refactor stable_page_flags() used by /proc/kpageflags without altering functionality. It uses BIT_ULL() to prevent shift-overflow warnings on 64-bit flag bits, converts folio-specific flag checks to standard folio_test_*() helpers, and removes redundant CONFIG_PAGE_IDLE_FLAG handling. - "Batch unmap of uffd-wp file folios" (Dev Jain) Extend batched folio unmapping support to file folios within userfaultfd write-protect (uffd-wp) VMAs by adding batching capabilities to pte_install_uffd_wp_if_needed(). This removes special-case restrictions on uffd-wp VMAs in try_to_unmap_one(), significantly simplifying the function's control flow and complexity. - "mm/early_ioremap: clarify and clean up early_ioremap_reset()" (Sang-Heon Jeon) Clarify and clean up the architecture-specific usage of __late_set_fixmap() and __late_clear_fixmap() after early_ioremap_reset() It adds explicit documentation regarding when early_ioremap_reset() must be called and removes redundant macro definitions and reset calls in the RISC-V and ARM64 architectures. - "mm: fix reclaim storms in defrag_mode" (Johannes Weiner) Address severe performance regressions, swap storms, and spurious OOMs caused by vm.defrag_mode=1 under high memory pressure in Meta production It updates the page allocator slowpath so non-movable allocation requests actively trigger direct reclaim and direct compaction at pageblock_order scale, allowing them to claim whole pageblocks rather than spinning unproductively. - "zram: lockmap tweaks" (Sebastian Siewior) Optimize and fix lockdep tracking for zram devices by consolidating per-entry lockmaps and isolate lock classes across multiple instances This reduces memory overhead by replacing per-entry lockdep_map instances with a single map per struct zram, and assigns a dynamic lock_class_key to each instance to prevent false deadlock reports when different zram devices are backed by distinct filesystems. * tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (501 commits) selftests/mm: thuge-gen: fix test_shmget() for PAGE_SIZE check selftests/mm: unpoison pages in memory-failure teardown mm/shmem: downgrade final i_blocks check in shmem_evict_inode() to pr_warn() mm/khugepaged: replace mutex_lock/mutex_unlock usage with guard macro mm/zsmalloc: fix release order of locks in zs_page_migrate() Documentation: zram: remove sections numbering ksm: stop iterating VMAs when ksm_test_exit returns true mm: fold userfaultfd_rwp() to false without CONFIG_ARCH_HAS_PTE_PROTNONE mm/migrate: report RCU-tasks quiescent states in migrate_pages_batch() zram: use a custom key for each zram object zram: move lockmap to be per-zram instead per table selftests/mm: fix gup_longterm EINVAL error message mm: page_alloc: fix non-movable reclaim storm in defrag_mode mm: page_alloc: move capture_control to the page allocator mm: compaction: support non-movable compaction for pageblock requests mm: page_alloc: __GFP_FS lockdep annotation for direct compaction hugetlb: evaluate subpool free state while locked mm/damon: remove trailing semicolons after function definitions mm/damon/ops-common: prevent migration fallback to non-target nodes mm/damon: update outdated comment about DAMOS filter handling ...

mm/rmap: rename vma_interval_tree_() to mapping_rmap_tree_()

2026-08-05T02:18:58+00:00

The family of vma_interval_tree_() functions manipulate the address_space (which, of course, is generally referred to as 'mapping') reverse mapping, but are named the 'VMA' interval tree. VMAs may be mapped by an anon_vma, an address_space, or both. Therefore calling the mapping interval tree a 'VMA' interval tree is rather confusing. This is also inconsistent with the anon_vma_interval_tree_*() functions which explicitly reference the rmap object to which they pertain. Rename the vma_interval_tree_*() functions to mapping_rmap_tree_*() to correct this. We will rename the anon rmap functions similarly in a subsequent patch. No functional change intended. Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-8-2a5aa403d977@kernel.org Signed-off-by: Lorenzo Stoakes Reviewed-by: Gregory Price Reviewed-by: Vlastimil Babka (SUSE) Reviewed-by: Zi Yan Cc: Ackerley Tng Cc: David Hildenbrand (Arm) Cc: Kai Huang Cc: Marek Szyprowski Cc: Pedro Falcato Cc: SJ Park Cc: Thomas Zimmermann Cc: Liam R. Howlett (Oracle) Signed-off-by: Andrew Morton

mm/rmap: parameterise vma_interval_tree_*() by address_space

2026-08-05T02:18:57+00:00

The file-backed mapping interval tree functions vma_interval_tree_*() accept a raw rb_root_cached pointer to determine the tree in which they are operating. However, in each case, this is always associated with an address_space data type. So simply pass a pointer to that instead to simplify the code, and more clearly differentiate between these operations and those concerning anonymous mappings. While we're here, make the generated interval tree functions static as they do not need to be used externally (any previously existing external users have now been removed). We also rename VMA parameters from 'node' to 'vma' as calling this a node is simply confusing, update the input index types to pgoff_t since they reference page offsets and rename the parameters to pgoff_start and pgoff_last. No functional change intended. Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-6-2a5aa403d977@kernel.org Signed-off-by: Lorenzo Stoakes Reviewed-by: Pedro Falcato Reviewed-by: Gregory Price Reviewed-by: Vlastimil Babka (SUSE) Reviewed-by: Zi Yan Cc: Ackerley Tng Cc: David Hildenbrand (Arm) Cc: Kai Huang Cc: Marek Szyprowski Cc: SJ Park Cc: Thomas Zimmermann Cc: Liam R. Howlett (Oracle) Signed-off-by: Andrew Morton

dax: fix misleading comment about share/index union in dax_folio_reset_order()

2026-07-14T23:26:42+00:00

The comment in dax_folio_reset_order() claims that DAX maintains an invariant where folio->share != 0 only when folio->mapping == NULL, implying folio->share is zero whenever mapping is non-NULL. This is misleading because folio->share and folio->index are a union -- for non-shared folios with mapping != NULL, reading folio->share returns the file page offset (folio->index), which is typically non-zero. Reword the comment to accurately describe the union aliasing: the assignment clears whichever interpretation of the union word is active (index for non-shared folios, share for shared folios), which is correct because the folio is being released in either case. No functional change -- the code was already correct, only the justification was wrong. Fixes: 59eb73b98ae0b ("dax: Factor out dax_folio_reset_order() helper") Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Reviewed-by: Alison Schofield Signed-off-by: John Groves Link: https://patch.msgid.link/0100019ecc08b8cd-4ee80eeb-1341-4f67-8478-7298129440e9-000000@email.amazonses.com Signed-off-by: Alison Schofield

Merge tag 'libnvdimm-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2026-04-21T21:12:01+00:00

Pull dax updates from Ira Weiny: "The series adds DAX support required for the upcoming fuse/famfs file system.[1] The support here is required because famfs is backed by devdax rather than pmem. This all lays the groundwork for using shared memory as a file system" Link: https://lore.kernel.org/all/0100019d43e5f632-f5862a3e-361c-4b54-a9a6-96c242a8f17a-000000@email.amazonses.com/ [1] * tag 'libnvdimm-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: dax/fsdev: fix uninitialized kaddr in fsdev_dax_zero_page_range() dax: export dax_dev_get() dax: Add fs_dax_get() func to prepare dax for fs-dax usage dax: Add dax_set_ops() for setting dax_operations at bind time dax: Add dax_operations for use by fs-dax on fsdev dax dax: Save the kva from memremap dax: add fsdev.c driver for fs-dax on character dax dax: Factor out dax_folio_reset_order() helper dax: move dax_pgoff_to_phys from [drivers/dax/] device.c to bus.c

fs: remove unncessary pagevec.h includes

2026-04-05T20:53:06+00:00

Remove unused pagevec.h includes from .c files. These were found with the following command: grep -rl '#include.*pagevec\.h' --include='*.c' | while read f; do grep -qE 'PAGEVEC_SIZE|folio_batch' "$f" || echo "$f" done There are probably more removal candidates in .h files, but those are more complex to analyze. Link: https://lkml.kernel.org/r/20260225-pagevec_cleanup-v2-2-716868cc2d11@columbia.edu Signed-off-by: Tal Zussman Reviewed-by: Jan Kara Acked-by: Zi Yan Acked-by: Chris Li Reviewed-by: Lorenzo Stoakes (Oracle) Cc: Christian Brauner Cc: David Hildenbrand (Arm) Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

mm: rename my_zero_pfn() to zero_pfn()

2026-04-05T20:53:01+00:00

my_zero_pfn() is a silly name. Rename zero_pfn variable to zero_page_pfn and my_zero_pfn() function to zero_pfn(). While on it, move extern declarations of zero_page_pfn outside the functions that use it and add a comment about what ZERO_PAGE is. Link: https://lkml.kernel.org/r/20260211103141.3215197-3-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: David Hildenbrand (Arm) Acked-by: Vlastimil Babka Reviewed-by: Liam R. Howlett Cc: Andreas Larsson Cc: "Borislav Petkov (AMD)" Cc: Catalin Marinas Cc: Christophe Leroy (CS GROUP) Cc: Dave Hansen Cc: David S. Miller Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Guo Ren Cc: Helge Deller Cc: Huacai Chen Cc: Ingo Molnar Cc: Johannes Berg Cc: John Paul Adrian Glaubitz Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Magnus Lindholm Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Hocko Cc: Michal Simek Cc: Palmer Dabbelt Cc: Richard Weinberger Cc: Russell King Cc: Stafford Horne Cc: Suren Baghdasaryan Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton

dax: add fsdev.c driver for fs-dax on character dax

2026-03-30T13:20:47+00:00

The new fsdev driver provides pages/folios initialized compatibly with fsdax - normal rather than devdax-style refcounting, and starting out with order-0 folios. When fsdev binds to a daxdev, it is usually (always?) switching from the devdax mode (device.c), which pre-initializes compound folios according to its alignment. Fsdev uses fsdev_clear_folio_state() to switch the folios into a fsdax-compatible state. A side effect of this is that raw mmap doesn't (can't?) work on an fsdev dax instance. Accordingly, The fsdev driver does not provide raw mmap - devices must be put in 'devdax' mode (drivers/dax/device.c) to get raw mmap capability. In this commit is just the framework, which remaps pages/folios compatibly with fsdax. Enabling dax changes: - bus.h: add DAXDRV_FSDEV_TYPE driver type - bus.c: allow DAXDRV_FSDEV_TYPE drivers to bind to daxdevs - dax.h: prototype inode_dax(), which fsdev needs Suggested-by: Dan Williams Suggested-by: Gregory Price Reviewed-by: Jonathan Cameron Signed-off-by: John Groves Link: https://patch.msgid.link/0100019d311cf904-419e9526-bdaf-4daa-97f1-5060b31a5c9f-000000@email.amazonses.com Signed-off-by: Ira Weiny

dax: Factor out dax_folio_reset_order() helper

2026-03-30T13:20:47+00:00

Both fs/dax.c:dax_folio_put() and drivers/dax/fsdev.c: fsdev_clear_folio_state() (the latter coming in the next commit after this one) contain nearly identical code to reset a compound DAX folio back to order-0 pages. Factor this out into a shared helper function. The new dax_folio_reset_order() function: - Clears the folio's mapping and share count - Resets compound folio state via folio_reset_order() - Clears PageHead and compound_head for each sub-page - Restores the pgmap pointer for each resulting order-0 folio - Returns the original folio order (for callers that need to advance by that many pages) Two intentional differences from the original dax_folio_put() logic: 1. folio->share is cleared unconditionally. This is correct because the DAX subsystem maintains the invariant that share != 0 only when mapping == NULL (enforced by dax_folio_make_shared()). dax_folio_put() ensures share has reached zero before calling this helper, so the unconditional clear is safe. 2. folio->pgmap is now explicitly restored for order-0 folios. For the dax_folio_put() caller this is a no-op (reads and writes back the same field). It is intentional for the upcoming fsdev_clear_folio_state() caller, which converts previously-compound folios and needs pgmap re-established for all pages regardless of order. This simplifies fsdev_clear_folio_state() from ~50 lines to ~15 lines. Suggested-by: Jonathan Cameron Reviewed-by: Ira Weiny Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Signed-off-by: John Groves Link: https://patch.msgid.link/0100019d311cc6b9-5be7428a-7f16-4774-8f90-a44b88ac5660-000000@email.amazonses.com Signed-off-by: Ira Weiny

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

2025-12-05T21:52:43+00:00

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 ...

kernel/git/stable/linux.git/fs/dax.c, branch master

Merge tag 'mm-stable-2026-08-18-18-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

mm/rmap: rename vma_interval_tree_*() to mapping_rmap_tree_*()

mm/rmap: parameterise vma_interval_tree_*() by address_space

dax: fix misleading comment about share/index union in dax_folio_reset_order()

Merge tag 'libnvdimm-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

fs: remove unncessary pagevec.h includes

mm: rename my_zero_pfn() to zero_pfn()

dax: add fsdev.c driver for fs-dax on character dax

dax: Factor out dax_folio_reset_order() helper

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

mm/rmap: rename vma_interval_tree_() to mapping_rmap_tree_()