kernel/linux.git/mm/backing-dev.c, branch v7.0-rc7

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

mm: add WQ_PERCPU to alloc_workqueue users

2026-01-31T22:22:39+00:00

This continues the effort to refactor workqueue APIs, which began with the introduction of new workqueues and a new alloc_workqueue flag in: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The refactoring is going to alter the default behavior of alloc_workqueue() to be unbound by default. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn't explicitly specify WQ_UNBOUND must now use WQ_PERCPU. For more details see the Link tag below. In order to keep alloc_workqueue() behavior identical, explicitly request WQ_PERCPU. [akpm@linux-foundation.org: fix mm/slub.c] [akpm@linux-foundation.org: fix kmem_cache_init_late() properly, per Sebastian] Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/ Link: https://lkml.kernel.org/r/20260113114630.152942-4-marco.crivellari@suse.com Signed-off-by: Marco Crivellari Suggested-by: Tejun Heo Reviewed-by: Sebastian Andrzej Siewior Reviewed-by: Frederic Weisbecker Cc: Alexander Potapenko Cc: David Hildenbrand Cc: Dmitry Vyukov Cc: Johannes Weiner Cc: Lai jiangshan Cc: "Liam R. Howlett" Cc: Lorenzo Stoakes Cc: Marco Elver Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Roman Gushchin Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: replace use of system_wq with system_percpu_wq

2026-01-31T22:22:39+00:00

This patch continues the effort to refactor workqueue APIs, which has begun with the changes introducing new workqueues and a new alloc_workqueue flag: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The point of the refactoring is to eventually alter the default behavior of workqueues to become unbound by default so that their workload placement is optimized by the scheduler. Before that to happen, workqueue users must be converted to the better named new workqueues with no intended behaviour changes: system_wq -> system_percpu_wq system_unbound_wq -> system_dfl_wq This way the old obsolete workqueues (system_wq, system_unbound_wq) can be removed in the future. Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/ Link: https://lkml.kernel.org/r/20260113114630.152942-3-marco.crivellari@suse.com Signed-off-by: Marco Crivellari Suggested-by: Tejun Heo Reviewed-by: Sebastian Andrzej Siewior Reviewed-by: Frederic Weisbecker Cc: Alexander Potapenko Cc: David Hildenbrand Cc: Dmitry Vyukov Cc: Johannes Weiner Cc: Lai jiangshan Cc: "Liam R. Howlett" Cc: Lorenzo Stoakes Cc: Marco Elver Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Roman Gushchin Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: replace use of system_unbound_wq with system_dfl_wq

2026-01-31T22:22:39+00:00

Patch series "Replace wq users and add WQ_PERCPU to alloc_workqueue() users", v2. This series continues the effort to refactor the Workqueue API. No behavior changes are introduced by this series. === Recent changes to the WQ API === The following, address the recent changes in the Workqueue API: - commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") - commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The old workqueues will be removed in a future release cycle and unbound will become the implicit default. === Introduced Changes by this series === 1) [P 1-2] Replace use of system_wq and system_unbound_wq Workqueue users converted to the better named new workqueues: system_wq -> system_percpu_wq system_unbound_wq -> system_dfl_wq This way the old obsolete workqueues (system_wq, system_unbound_wq) can be removed in the future. 2) [P 3] add WQ_PERCPU to remaining alloc_workqueue() users With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND must now use WQ_PERCPU. WQ_UNBOUND will be removed in future. For more information: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/ This patch (of 3): This patch continues the effort to refactor workqueue APIs, which has begun with the changes introducing new workqueues and a new alloc_workqueue flag: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The point of the refactoring is to eventually alter the default behavior of workqueues to become unbound by default so that their workload placement is optimized by the scheduler. Before that to happen, workqueue users must be converted to the better named new workqueues with no intended behaviour changes: system_wq -> system_percpu_wq system_unbound_wq -> system_dfl_wq This way the old obsolete workqueues (system_wq, system_unbound_wq) can be removed in the future. Link: https://lkml.kernel.org/r/20260113114630.152942-1-marco.crivellari@suse.com Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/ Link: https://lkml.kernel.org/r/20260113114630.152942-2-marco.crivellari@suse.com Signed-off-by: Marco Crivellari Suggested-by: Tejun Heo Reviewed-by: Sebastian Andrzej Siewior Reviewed-by: Frederic Weisbecker Cc: Alexander Potapenko Cc: David Hildenbrand Cc: Dmitry Vyukov Cc: Johannes Weiner Cc: Lai jiangshan Cc: "Liam R. Howlett" Cc: Lorenzo Stoakes Cc: Marco Elver Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Roman Gushchin Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/block/fs: remove laptop_mode

2026-01-21T03:24:47+00:00

Laptop mode was introduced to save battery, by delaying and consolidating writes and thereby maximize the time rotating hard drives wouldn't have to spin. Luckily, rotating hard drives, with their high spin-up times and power draw, are a thing of the past for battery-powered devices. Reclaim has also since changed to not write single filesystem pages anymore, and regular filesystem writeback is lumpy by design. The juice doesn't appear worth the squeeze anymore. The footprint of the feature is small, but nevertheless it's a complicating factor in mm, block, filesystems. Developers don't think about it, and it likely hasn't been tested with new reclaim and writeback changes in years. Let's sunset it. Keep the sysctl with a deprecation warning around for a few more cycles, but remove all functionality behind it. [akpm@linux-foundation.org: fix Documentation/admin-guide/laptops/index.rst] Link: https://lkml.kernel.org/r/20251216185201.GH905277@cmpxchg.org Signed-off-by: Johannes Weiner Suggested-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Acked-by: Jens Axboe Reviewed-by: Shakeel Butt Acked-by: Michal Hocko Cc: Deepanshu Kartikey Signed-off-by: Andrew Morton

Coccinelle-based conversion to use ->i_state accessors

2025-10-20T18:22:26+00:00

All places were patched by coccinelle with the default expecting that ->i_lock is held, afterwards entries got fixed up by hand to use unlocked variants as needed. The script: @@ expression inode, flags; @@ - inode->i_state & flags + inode_state_read(inode) & flags @@ expression inode, flags; @@ - inode->i_state &= ~flags + inode_state_clear(inode, flags) @@ expression inode, flag1, flag2; @@ - inode->i_state &= ~flag1 & ~flag2 + inode_state_clear(inode, flag1 | flag2) @@ expression inode, flags; @@ - inode->i_state |= flags + inode_state_set(inode, flags) @@ expression inode, flags; @@ - inode->i_state = flags + inode_state_assign(inode, flags) @@ expression inode, flags; @@ - flags = inode->i_state + flags = inode_state_read(inode) @@ expression inode, flags; @@ - READ_ONCE(inode->i_state) & flags + inode_state_read(inode) & flags Signed-off-by: Mateusz Guzik Signed-off-by: Christian Brauner

Merge tag 'fuse-update-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

2025-10-03T19:48:18+00:00

Pull fuse updates from Miklos Szeredi: - Extend copy_file_range interface to be fully 64bit capable (Miklos) - Add selftest for fusectl (Chen Linxuan) - Move fuse docs into a separate directory (Bagas Sanjaya) - Allow fuse to enter freezable state in some cases (Sergey Senozhatsky) - Clean up writeback accounting after removing tmp page copies (Joanne) - Optimize virtiofs request handling (Li RongQing) - Add synchronous FUSE_INIT support (Miklos) - Allow server to request prune of unused inodes (Miklos) - Fix deadlock with AIO/sync release (Darrick) - Add some prep patches for block/iomap support (Darrick) - Misc fixes and cleanups * tag 'fuse-update-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (26 commits) fuse: move CREATE_TRACE_POINTS to a separate file fuse: move the backing file idr and code into a new source file fuse: enable FUSE_SYNCFS for all fuseblk servers fuse: capture the unique id of fuse commands being sent fuse: fix livelock in synchronous file put from fuseblk workers mm: fix lockdep issues in writeback handling fuse: add prune notification fuse: remove redundant calls to fuse_copy_finish() in fuse_notify() fuse: fix possibly missing fuse_copy_finish() call in fuse_notify() fuse: remove FUSE_NOTIFY_CODE_MAX from fuse: remove fuse_readpages_end() null mapping check fuse: fix references to fuse.rst -> fuse/fuse.rst fuse: allow synchronous FUSE_INIT fuse: zero initialize inode private data fuse: remove unused 'inode' parameter in fuse_passthrough_open virtio_fs: fix the hash table using in virtio_fs_enqueue_req() mm: remove BDI_CAP_WRITEBACK_ACCT fuse: use default writeback accounting virtio_fs: Remove redundant spinlock in virtio_fs_request_complete() fuse: remove unneeded offset assignment when filling write pages ...

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

2025-10-03T01:18:33+00:00

Pull MM updates from Andrew Morton: - "mm, swap: improve cluster scan strategy" from Kairui Song improves performance and reduces the failure rate of swap cluster allocation - "support large align and nid in Rust allocators" from Vitaly Wool permits Rust allocators to set NUMA node and large alignment when perforning slub and vmalloc reallocs - "mm/damon/vaddr: support stat-purpose DAMOS" from Yueyang Pan extend DAMOS_STAT's handling of the DAMON operations sets for virtual address spaces for ops-level DAMOS filters - "execute PROCMAP_QUERY ioctl under per-vma lock" from Suren Baghdasaryan reduces mmap_lock contention during reads of /proc/pid/maps - "mm/mincore: minor clean up for swap cache checking" from Kairui Song performs some cleanup in the swap code - "mm: vm_normal_page*() improvements" from David Hildenbrand provides code cleanup in the pagemap code - "add persistent huge zero folio support" from Pankaj Raghav provides a block layer speedup by optionalls making the huge_zero_pagepersistent, instead of releasing it when its refcount falls to zero - "kho: fixes and cleanups" from Mike Rapoport adds a few touchups to the recently added Kexec Handover feature - "mm: make mm->flags a bitmap and 64-bit on all arches" from Lorenzo Stoakes turns mm_struct.flags into a bitmap. To end the constant struggle with space shortage on 32-bit conflicting with 64-bit's needs - "mm/swapfile.c and swap.h cleanup" from Chris Li cleans up some swap code - "selftests/mm: Fix false positives and skip unsupported tests" from Donet Tom fixes a few things in our selftests code - "prctl: extend PR_SET_THP_DISABLE to only provide THPs when advised" from David Hildenbrand "allows individual processes to opt-out of THP=always into THP=madvise, without affecting other workloads on the system". It's a long story - the [1/N] changelog spells out the considerations - "Add and use memdesc_flags_t" from Matthew Wilcox gets us started on the memdesc project. Please see https://kernelnewbies.org/MatthewWilcox/Memdescs and https://blogs.oracle.com/linux/post/introducing-memdesc - "Tiny optimization for large read operations" from Chi Zhiling improves the efficiency of the pagecache read path - "Better split_huge_page_test result check" from Zi Yan improves our folio splitting selftest code - "test that rmap behaves as expected" from Wei Yang adds some rmap selftests - "remove write_cache_pages()" from Christoph Hellwig removes that function and converts its two remaining callers - "selftests/mm: uffd-stress fixes" from Dev Jain fixes some UFFD selftests issues - "introduce kernel file mapped folios" from Boris Burkov introduces the concept of "kernel file pages". Using these permits btrfs to account its metadata pages to the root cgroup, rather than to the cgroups of random inappropriate tasks - "mm/pageblock: improve readability of some pageblock handling" from Wei Yang provides some readability improvements to the page allocator code - "mm/damon: support ARM32 with LPAE" from SeongJae Park teaches DAMON to understand arm32 highmem - "tools: testing: Use existing atomic.h for vma/maple tests" from Brendan Jackman performs some code cleanups and deduplication under tools/testing/ - "maple_tree: Fix testing for 32bit compiles" from Liam Howlett fixes a couple of 32-bit issues in tools/testing/radix-tree.c - "kasan: unify kasan_enabled() and remove arch-specific implementations" from Sabyrzhan Tasbolatov moves KASAN arch-specific initialization code into a common arch-neutral implementation - "mm: remove zpool" from Johannes Weiner removes zspool - an indirection layer which now only redirects to a single thing (zsmalloc) - "mm: task_stack: Stack handling cleanups" from Pasha Tatashin makes a couple of cleanups in the fork code - "mm: remove nth_page()" from David Hildenbrand makes rather a lot of adjustments at various nth_page() callsites, eventually permitting the removal of that undesirable helper function - "introduce kasan.write_only option in hw-tags" from Yeoreum Yun creates a KASAN read-only mode for ARM, using that architecture's memory tagging feature. It is felt that a read-only mode KASAN is suitable for use in production systems rather than debug-only - "mm: hugetlb: cleanup hugetlb folio allocation" from Kefeng Wang does some tidying in the hugetlb folio allocation code - "mm: establish const-correctness for pointer parameters" from Max Kellermann makes quite a number of the MM API functions more accurate about the constness of their arguments. This was getting in the way of subsystems (in this case CEPH) when they attempt to improving their own const/non-const accuracy - "Cleanup free_pages() misuse" from Vishal Moola fixes a number of code sites which were confused over when to use free_pages() vs __free_pages() - "Add Rust abstraction for Maple Trees" from Alice Ryhl makes the mapletree code accessible to Rust. Required by nouveau and by its forthcoming successor: the new Rust Nova driver - "selftests/mm: split_huge_page_test: split_pte_mapped_thp improvements" from David Hildenbrand adds a fix and some cleanups to the thp selftesting code - "mm, swap: introduce swap table as swap cache (phase I)" from Chris Li and Kairui Song is the first step along the path to implementing "swap tables" - a new approach to swap allocation and state tracking which is expected to yield speed and space improvements. This patchset itself yields a 5-20% performance benefit in some situations - "Some ptdesc cleanups" from Matthew Wilcox utilizes the new memdesc layer to clean up the ptdesc code a little - "Fix va_high_addr_switch.sh test failure" from Chunyu Hu fixes some issues in our 5-level pagetable selftesting code - "Minor fixes for memory allocation profiling" from Suren Baghdasaryan addresses a couple of minor issues in relatively new memory allocation profiling feature - "Small cleanups" from Matthew Wilcox has a few cleanups in preparation for more memdesc work - "mm/damon: add addr_unit for DAMON_LRU_SORT and DAMON_RECLAIM" from Quanmin Yan makes some changes to DAMON in furtherance of supporting arm highmem - "selftests/mm: Add -Wunreachable-code and fix warnings" from Muhammad Anjum adds that compiler check to selftests code and fixes the fallout, by removing dead code - "Improvements to Victim Process Thawing and OOM Reaper Traversal Order" from zhongjinji makes a number of improvements in the OOM killer: mainly thawing a more appropriate group of victim threads so they can release resources - "mm/damon: misc fixups and improvements for 6.18" from SeongJae Park is a bunch of small and unrelated fixups for DAMON - "mm/damon: define and use DAMON initialization check function" from SeongJae Park implement reliability and maintainability improvements to a recently-added bug fix - "mm/damon/stat: expose auto-tuned intervals and non-idle ages" from SeongJae Park provides additional transparency to userspace clients of the DAMON_STAT information - "Expand scope of khugepaged anonymous collapse" from Dev Jain removes some constraints on khubepaged's collapsing of anon VMAs. It also increases the success rate of MADV_COLLAPSE against an anon vma - "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()" from Lorenzo Stoakes moves us further towards removal of file_operations.mmap(). This patchset concentrates upon clearing up the treatment of stacked filesystems - "mm: Improve mlock tracking for large folios" from Kiryl Shutsemau provides some fixes and improvements to mlock's tracking of large folios. /proc/meminfo's "Mlocked" field became more accurate - "mm/ksm: Fix incorrect accounting of KSM counters during fork" from Donet Tom fixes several user-visible KSM stats inaccuracies across forks and adds selftest code to verify these counters - "mm_slot: fix the usage of mm_slot_entry" from Wei Yang addresses some potential but presently benign issues in KSM's mm_slot handling * tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (372 commits) mm: swap: check for stable address space before operating on the VMA mm: convert folio_page() back to a macro mm/khugepaged: use start_addr/addr for improved readability hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list alloc_tag: fix boot failure due to NULL pointer dereference mm: silence data-race in update_hiwater_rss mm/memory-failure: don't select MEMORY_ISOLATION mm/khugepaged: remove definition of struct khugepaged_mm_slot mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL hugetlb: increase number of reserving hugepages via cmdline selftests/mm: add fork inheritance test for ksm_merging_pages counter mm/ksm: fix incorrect KSM counter handling in mm_struct during fork drivers/base/node: fix double free in register_one_node() mm: remove PMD alignment constraint in execmem_vmalloc() mm/memory_hotplug: fix typo 'esecially' -> 'especially' mm/rmap: improve mlock tracking for large folios mm/filemap: map entire large folio faultaround mm/fault: try to map the entire file folio in finish_fault() mm/rmap: mlock large folios in try_to_unmap_one() mm/rmap: fix a mlock race condition in folio_referenced_one() ...

writeback: Avoid contention on wb->list_lock when switching inodes

2025-09-19T11:11:00+00:00

There can be multiple inode switch works that are trying to switch inodes to / from the same wb. This can happen in particular if some cgroup exits which owns many (thousands) inodes and we need to switch them all. In this case several inode_switch_wbs_work_fn() instances will be just spinning on the same wb->list_lock while only one of them makes forward progress. This wastes CPU cycles and quickly leads to softlockup reports and unusable system. Instead of running several inode_switch_wbs_work_fn() instances in parallel switching to the same wb and contending on wb->list_lock, run just one work item per wb and manage a queue of isw items switching to this wb. Acked-by: Tejun Heo Signed-off-by: Jan Kara

mm: replace (20 - PAGE_SHIFT) with common macros for pages<->MB conversion

2025-09-13T23:54:42+00:00

Replace repeated (20 - PAGE_SHIFT) calculations with standard macros: - MB_TO_PAGES(mb) converts MB to page count - PAGES_TO_MB(pages) converts pages to MB No functional change. [akpm@linux-foundation.org: remove arc's private PAGES_TO_MB, remove its unused PAGES_TO_KB] [akpm@linux-foundation.org: don't include mm.h due to include file ordering mess] Link: https://lkml.kernel.org/r/20250718024134.1304745-1-ye.liu@linux.dev Signed-off-by: Ye Liu Acked-by: Zi Yan Reviewed-by: Lorenzo Stoakes Reviewed-by: Dev Jain Acked-by: David Hildenbrand Acked-by: Chris Li Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Ben Segall Cc: Boqun Feng Cc: Davidlohr Bueso Cc: Dietmar Eggemann Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Josh Triplett Cc: Juri Lelli Cc: Kairui Song Cc: Kemeng Shi Cc: Lai jiangshan Cc: Liam Howlett Cc: Mariano Pache Cc: Mathieu Desnoyers Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Rapoport Cc: Neeraj Upadhyay Cc: Nhat Pham Cc: "Paul E . McKenney" Cc: Peter Zijlstra Cc: Ryan Roberts Cc: Steven Rostedt Cc: Suren Baghdasaryan Cc: "Uladzislau Rezki (Sony)" Cc: Valentin Schneider Cc: Vincent Guittot Cc: Vlastimil Babka Signed-off-by: Andrew Morton