kernel/linux.git/mm/mm_init.c, branch v7.2-rc1

Merge tag 'liveupdate-v7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux

2026-06-21T16:46:14+00:00

Pull liveupdate updates from Mike Rapoport: "Kexec Handover (KHO): - make memory preservation compatible with deferred initialization of the memory map Live Update Orchestrator (LUO): - add LIVEUPDATE_SESSION_GET_NAME ioctl and parameter verification for LIVEUPDATE_IOCTL_CREATE_SESSION ioctl - documentation updates for liveupdate=on command line option, systemd support and the current compatibility status - remove the fixed limits on the number of files that can be preserved within a single session, and the total number of sessions managed by the LUO Misc fixes: - reference count incoming File-Lifecycle-Bound (FLB) data so it cannot be freed while a subsystem is still using it - fixes for a TOCTOU race in luo_session_retrieve(), a use- after-free in the file finish and unpreserve paths, concurrent session mutations during reboot and serialization on preserve_context kexec - make sure ioctls for incoming LUO sessions are blocked for outgoing sessions and vice versa - make sure KHO scratch size is always aligned by CMA_MIN_ALIGNMENT_BYTES - fix memblock tests build issue introduced by KHO changes" * tag 'liveupdate-v7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux: (36 commits) liveupdate: Document that retrieve failure is permanent docs: memfd_preservation: fix rendering of ABI documentation selftests/liveupdate: Add stress-files kexec test selftests/liveupdate: Add stress-sessions kexec test selftests/liveupdate: Test session and file limit removal liveupdate: Remove limit on the number of files per session liveupdate: Remove limit on the number of sessions liveupdate: defer session block allocation and physical address setting kho: add support for linked-block serialization liveupdate: Extract luo_session_deserialize_one helper liveupdate: Extract luo_file_deserialize_one helper liveupdate: register luo_ser as KHO subtree liveupdate: centralize state management into struct luo_ser liveupdate: avoid mixing cleanup guards with goto in luo_session_retrieve_fd liveupdate: change file_set->count type to u64 for type safety liveupdate: Remove unused ser field from struct luo_session liveupdate: fix u-a-f in luo_file_unpreserve_files() and luo_file_finish() liveupdate: block session mutations during reboot liveupdate: fix TOCTOU race in luo_session_retrieve() liveupdate: skip serialization for context-preserving kexec ...

Merge tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-06-19T17:14:34+00:00

Pull MM updates from Andrew Morton: - "selftests/mm: clean up build output and verbosity" (Li Wang) Remove some noise from the MM selftests build - "mm: Free contiguous order-0 pages efficiently" (Ryan Roberts) Speed up the freeing of a batch of 0-order pages by first scanning them for coalescing opportunities. This is applicable to vfree() and to the releasing of frozen pages - "mm/damon: introduce DAMOS failed region quota charge ratio" (SeongJae Park) Address a DAMOS usability issue: The DAMOS quota often exhausts prematurely because it charges for all memory attempted, causing slow and inconsistent performance when actions fail on unreclaimable memory. To fix this, a new feature lets users set a smaller, flexible quota charge ratio (via a numerator and denominator) for failed regions. Since failed actions cause less overhead, reducing their quota cost ensures more predictable and efficient DAMOS processing - "selftests/cgroup: improve zswap tests robustness and support large page sizes" (Li Wang) Fix various spurious failures and improves the overall robustness of the cgroup zswap selftests - "fix MAP_DROPPABLE not supported errno" (Anthony Yznaga) Fix an issue in the mlock selftests on arm32 - "mm: huge_memory: clean up defrag sysfs with shared" (Breno Leitao) Some maintenance work in the huge_memory code - "treewide: fixup gfp_t printks" (Brendan Jackman) Use the special vprintf() gfp_t conversion in various places - "mm: Fix vmemmap optimization accounting and initialization" (Muchun Song) Fix several bugs in the vmemmap optimization, mainly around incorrect page accounting and memmap initialization in the DAX and memory hotplug paths. It also fixes pageblock migratetype initialization and struct page initialization for ZONE_DEVICE compound pages - "mm/damon: repost non-hotfix reviewed patches in damon/next tree" A sprinkle of unrelated minor bugfixes for DAMON - "mm: remove page_mapped()" (David Hildenbrand) Remove this function from the tree, replacing it with folio_mapped() - "mm/damon: let DAMON be paused and resumed" (SeongJae Park) Allow DAMON to be paused and resumed without losing its current state - "kasan: hw_tags: Disable tagging for stack and page-tables" (Muhammad Usama Anjum) Simplify and speed up kasan by removing its ineffective tagging of stacks and page tables - "mm/damon/reclaim,lru_sort: monitor all system rams by default" (SeongJae Park) Simplify deployment on diverse hardware like NUMA systems by updating DAMON_RECLAIM and DAMON_LRU_SORT to automatically monitor the physical address range covering all System RAM areas by default, replacing the overly restrictive behavior that only targeted the single largest memory block to save on negligible overhead - "mm/damon/sysfs: document filters/ directory as deprecated" (SeongJae Park) Update some DAMON docs - "mm: use spinlock guards for zone lock" (Dmitry Ilvokhin) Switch zone->lock handling over to using the guard() mechanisms - "mm/filemap: tighten mmap_miss hit accounting" (fujunjie) Fix a flaw where the mmap_miss counter over-credited page cache hits during fault-arounds and page-fault retries. This results in significant reduction of redundant synchronous mmap readahead I/O, drastically cutting down execution time and gigabytes read for sparse random or strided memory access workloads - "selftests/cgroup: Fix false positive failures in test_percpu_basic" (Li Wang) Fix a couple of false-positives in the cgroup kmem selftests - "mm/damon/reclaim: support monitoring intervals auto-tuning" (SeongJae Park) Add a new parameter to DAMON permitting DAMON_RECLAIM to automatically tune DAMON's sampling and aggregation intervals - "mm/damon/stat: add kdamond_pid parameter" (SeongJae Park) Change DAMON_STAT to provide the pid of its kdamond - "mm/kmemleak: dedupe verbose scan output" (Breno Leitao) Remove large amounts of duplicated backtraces from the verbose-mode kmemleak output - "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 1)" (David Hildenbrand) Reduce our use of CONFIG_HAVE_BOOTMEM_INFO_NODE, with a view to removing it entirely in a later series - "mm/damon: validate min_region_size to be power of 2" (Liew Rui Yan) Prevent users from passing a non-power-of-2 value of `addr_unit', as this later results in undesirable behavior - "mm: document read_pages and simplify usage" (Frederick Mayle) - "tools/mm/page-types: Fix misc bugs" (Ye Liu) Fix three issues in tools/mm/page-types.c - "mm: misc cleanups from __GFP_UNMAPPED series" (Brendan Jackman) Implement several cleanups in the page allocator and related code - "mm, swap: swap table phase IV: unify allocation" (Kairui Song) Unify the allocation and charging of anon and shmem swap in folios, provides better synchronization, consolidates the metadata management, hence dropping the static array and map, and improves performance - "mm/damon: introduce data attributes monitoring" (SeongJae Park( Extend DAMON to monitor general data attributes other than accesses - "mm/vmalloc: free unused pages on vrealloc() shrink" (Shivam Kalra) Implement the TODO in vrealloc() to unmap and free unused pages when shrinking across a page boundary - "mm/damon: documentation and comment fixes" (niecheng) - "remove mmap_action success, error hooks" (Lorenzo Stoakes) Eliminate custom hooks from mmap_action by removing the problematic success_hook which allowed drivers to improperly access uninitialized VMAs. It replaces the error_hook with a simple error-code field and updates the memory char driver accordingly - "mm/damon: minor improvements for code readability and tests" (SeongJae Park) - "mm/damon: fix macro arguments and clarify quota goals doc" (Maksym Shcherba) - "userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c" (Mike Rapoport) - "mm/mglru: improve reclaim loop and dirty folio" (Kairui Song and others) Clean up and slightly improves MGLRU's reclaim loop and dirty writeback handling. Large performance improvements are measured - "use vma locks for proc/pid/{smaps|numa_maps} reads" (Suren Baghdasaryan) Use per-vma locks when reading /proc/pid/smaps and numa_maps similar to reduce contention on central mmap_lock - "refactors thpsize_shmem_enabled_store() and thpsize_shmem_enabled_show()" (Ran Xiaokai) Some cleanup work in the THP code - "selftests/memfd: fix compilation warnings" (Konstantin Khorenko) Fix a few build glitches in the memfd selftest code. - "memcg: shrink obj_stock_pcp and cache multiple objcgs" (Shakeel Butt) Resolve a 68% performance regression caused by NUMA-node cache thrashing around struct obj_stock_pcp by shrinking its existing fields and expanding it into a multi-slot array that caches up to five obj_cgroup pointers per CPU, allowing per-node variants of the same memcg to coexist within a single 64-byte cache line. - "zram: writeback fixes" (Sergey Senozhatsky) address a couple of unrelated zram writeback issues - "mm: switch THP shrinker to list_lru" (Johannes Weiner) Resolve NUMA-awareness issues and streamlines callsite interaction by refactoring and extending the list_lru API to completely replace the complex, open-coded deferred split queue for Transparent Huge Pages - "mm: improve large folio readahead for exec memory" (Usama Arif) Improve large-folio readahead on systems like 64K-page arm64 by preventing the mmap_miss check from permanently disabling target-oriented VM_EXEC readahead, and by generalizing the force_thp_readahead gate to support mappings with any usefully large maximum folio order under the cache cap. - "userfaultfd/pagemap: pre-existing fixes" (Kiryl Shutsemau) Fix a bunch of minor issues in the userfaultfd/pagemap, all of which were flagged by Sashiko review of proposed new material - "mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and vmemmap_check_pmd()" (Muchun Song) Provide generic versions of these two functions so the four arch-specific implementations can be removed. - "mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device" (Youngjun Park) Address a uswsusp-vs-swapoff race and reduces the swap device reference taking/releasing frequency. - "mm/hmm: A fix and a selftest" (Dev Jain) * tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) selftests/mm/hmm-tests: test pagemap reads of PMD device-private entries fs/proc/task_mmu: do not warn on seeing non-migration pmd entry lib/test_hmm: check alloc_page_vma() return value and handle OOM mm/compaction: cap compact_gap() at COMPACT_CLUSTER_MAX mm/swap: remove redundant swap device reference in alloc/free mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device mm/filemap: use folio_next_index() for start vmalloc: fix NULL pointer dereference in is_vm_area_hugepages() sparc/mm: drop vmemmap_check_pmd helper and use generic code loongarch/mm: drop vmemmap_check_pmd helper and use generic code riscv/mm: drop vmemmap_pmd helpers and use generic code arm64/mm: drop vmemmap_pmd helpers and use generic code mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd() rust: page: mark Page::nid as inline userfaultfd: build __VMA_UFFD_FLAGS from config-gated masks userfaultfd: gate must_wait writability check on pte_present() mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole() fs/proc/task_mmu: use huge_page_size() in pagemap_scan_hugetlb_entry() fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race ...

Merge tag 'memblock-v7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock

2026-06-17T19:16:28+00:00

Pull memblock updates from Mike Rapoport: "Small fixes and a cleanup: - numa emulation: fix detection of under-allocated emulated nodes - memblock tests: fix NUMA tests to properly differentiate reserved areas with differnet flags - mm_init: use div64_ul() instead of do_div() to better express the intent of the division" * tag 'memblock-v7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock: mm: mm_init: use div64_ul() instead of do_div() tools/testing/memblock: fix stale NUMA reservation tests mm/fake-numa: fix under-allocation detection in uniform split

mm: switch deferred split shrinker to list_lru

2026-06-09T01:21:25+00:00

The deferred split queue handles cgroups in a suboptimal fashion. The queue is per-NUMA node or per-cgroup, not the intersection. That means on a cgrouped system, a node-restricted allocation entering reclaim can end up splitting large pages on other nodes: alloc/unmap deferred_split_folio() list_add_tail(memcg->split_queue) set_shrinker_bit(memcg, node, deferred_shrinker_id) for_each_zone_zonelist_nodemask(restricted_nodes) mem_cgroup_iter() shrink_slab(node, memcg) shrink_slab_memcg(node, memcg) if test_shrinker_bit(memcg, node, deferred_shrinker_id) deferred_split_scan() walks memcg->split_queue The shrinker bit adds an imperfect guard rail. As soon as the cgroup has a single large page on the node of interest, all large pages owned by that memcg, including those on other nodes, will be split. list_lru properly sets up per-node, per-cgroup lists. As a bonus, it streamlines a lot of the list operations and reclaim walks. It's used widely by other major shrinkers already. Convert the deferred split queue as well. The list_lru per-memcg heads are instantiated on demand when the first object of interest is allocated for a cgroup, by calling folio_memcg_alloc_deferred(). Add calls to where splittable pages are created: anon faults, swapin faults, khugepaged collapse. These calls create all possible node heads for the cgroup at once, so the migration code (between nodes) doesn't need any special care. [akpm@linux-foundation.org: fix build with CONFIG_TRANSPARENT_HUGEPAGE=n] Link: https://lore.kernel.org/202605281620.lc3rtkBm-lkp@intel.com [hannes@cmpxchg.org: fix cgroup.memory=nokmem handling] Link: https://lore.kernel.org/ah9PGv12mqai84ES@cmpxchg.org Link: https://lore.kernel.org/20260527204757.2544958-10-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Reported-by: Mikhail Zaslonko Tested-by: Mikhail Zaslonko Acked-by: Shakeel Butt Reviewed-by: Lorenzo Stoakes (Oracle) Acked-by: Usama Arif Reviewed-by: Kairui Song Cc: Baolin Wang Cc: Barry Song Cc: Dave Chinner Cc: David Hildenbrand (Arm) Cc: Dev Jain Cc: Lance Yang Cc: Liam R. Howlett Cc: Michal Hocko Cc: Muchun Song Cc: Nico Pache Cc: Roman Gushchin Cc: Ryan Roberts Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Zi Yan Cc: kernel test robot Signed-off-by: Andrew Morton

mm: introduce for_each_free_list()

2026-06-02T22:22:19+00:00

Patch series "mm: misc cleanups from __GFP_UNMAPPED series". In v2 of the __GFP_UNMAPPED series [0], we realised that some of the patches could potentially be merged as independent cleanups. These are all independent of one another, if you think some are useful cleanups and others are pointless churn, it should be fine to just pick whatever subset you prefer. No functional change intended. This patch (of 4): There are a couple of places that iterate over the freelists with awareness of the data structures' layout. It seems ideally, code outside of mm should not be aware of the page allocator's freelists at all. But, this patch just doesn't hide them completely, it's just a meek incremental step in that direction: provide a macro to iterate over it without needing to be aware of the actual struct fields. Link: https://lore.kernel.org/20260513-page_alloc-unmapped-prep-v1-0-dacdf5402be8@google.com Link: https://lore.kernel.org/20260513-page_alloc-unmapped-prep-v1-1-dacdf5402be8@google.com Link: https://lore.kernel.org/all/20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@google.com/ [0] Signed-off-by: Brendan Jackman Acked-by: Mike Rapoport (Microsoft) Reviewed-by: Vlastimil Babka (SUSE) Cc: Axel Rasmussen Cc: Barry Song Cc: David Hildenbrand Cc: Johannes Weiner Cc: Kairui Song Cc: Len Brown Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: "Rafael J. Wysocki" Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Wei Xu Cc: Yuanchu Xie Cc: Zi Yan Signed-off-by: Andrew Morton

mm: Make empty_zero_page[] const

2026-06-02T15:29:16+00:00

The empty zero page is used to back any kernel or user space mapping that is supposed to remain cleared, and so the page itself is never supposed to be modified. So mark it as const, which moves it into .rodata rather than .bss: on most architectures, this ensures that both the kernel's mapping of it and any aliases that are accessible via the kernel direct (linear) map are mapped read-only, and cannot be used (inadvertently or maliciously) to corrupt the contents of the zero page. Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Kevin Brodsky Acked-by: David Hildenbrand (Arm) Reviewed-by: Jann Horn Reviewed-by: Feng Tang Signed-off-by: Ard Biesheuvel Signed-off-by: Will Deacon

mm: mm_init: use div64_ul() instead of do_div()

2026-06-02T13:10:31+00:00

Fixes Coccinelle/coccicheck warning reported by do_div.cocci. Compared to do_div(), div64_ul() does not implicitly cast the divisor and does not unnecessarily calculate the remainder. There are no functional changes. The benefit is purely a semantic cleanup that better communicates the intent of the division and resolves the static analysis warning. Signed-off-by: Giorgi Tchankvetadze Link: https://patch.msgid.link/20260602-mm-div64-cleanup-v1-1-bf5d67d89d93@gmail.com Signed-off-by: Mike Rapoport (Microsoft)

kho: fix deferred initialization of scratch areas

2026-05-31T23:31:37+00:00

Currently, if CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, kho_release_scratch() will initialize the struct pages and set migratetype of KHO scratch. Unless the whole scratch fits below first_deferred_pfn, some of that will be overwritten either by deferred_init_pages() or memmap_init_reserved_range(). To fix it, make memmap_init_range(), deferred_init_memmap_chunk() and __init_page_from_nid() recognize KHO scratch regions and set migratetype of pageblocks in those regions to MIGRATE_CMA. Co-developed-by: Mike Rapoport (Microsoft) Signed-off-by: Michal Clapinski Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pasha Tatashin Reviewed-by: Pratyush Yadav (Google) Link: https://patch.msgid.link/20260423122538.140993-2-mclapinski@google.com Signed-off-by: Mike Rapoport (Microsoft)

mm/mm_init: fix uninitialized struct pages for ZONE_DEVICE

2026-05-29T04:04:55+00:00

If DAX memory is hotplugged into an unoccupied subsection of an early section, section_activate() reuses the unoptimized boot memmap. However, compound_nr_pages() still assumes that vmemmap optimization is in effect and initializes only the reduced number of struct pages. As a result, the remaining tail struct pages are left uninitialized, which can later lead to unexpected behavior or crashes. Fix this by treating early sections as unoptimized when calculating how many struct pages to initialize. Link: https://lore.kernel.org/20260428081855.1249045-7-songmuchun@bytedance.com Fixes: 6fd3620b3428 ("mm/page_alloc: reuse tail struct pages for compound devmaps") Signed-off-by: Muchun Song Acked-by: David Hildenbrand (Arm) Acked-by: Mike Rapoport (Microsoft) Acked-by: Liam R. Howlett Cc: "Aneesh Kumar K.V" Cc: Joao Martins Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton

mm/mm_init: fix pageblock migratetype for ZONE_DEVICE compound pages

2026-05-29T04:04:54+00:00

The memmap_init_zone_device() function only initializes the migratetype of the first pageblock of a compound page. If the compound page size exceeds pageblock_nr_pages (e.g., 1GB hugepages with 2MB pageblocks), subsequent pageblocks in the compound page remain uninitialized. Move the migratetype initialization out of __init_zone_device_page() and into a separate pageblock_migratetype_init_range() function. This iterates over the entire PFN range of the memory, ensuring that all pageblocks are correctly initialized. Also remove the stale confusing comment about MEMINIT_HOTPLUG above the migratetype setting since it is an obsolete relic from commit 966cf44f637e ("mm: defer ZONE_DEVICE page initialization to the point where we init pgmap") and no longer makes sense here. Link: https://lore.kernel.org/20260428081855.1249045-6-songmuchun@bytedance.com Fixes: c4386bd8ee3a ("mm/memremap: add ZONE_DEVICE support for compound pages") Signed-off-by: Muchun Song Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Oscar Salvador Acked-by: David Hildenbrand (Arm) Acked-by: Liam R. Howlett Cc: "Aneesh Kumar K.V" Cc: Joao Martins Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Nicholas Piggin Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton