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2026-08-27Merge tag 'mm-stable-2026-08-26-15-22' of ↵Linus Torvalds1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull more MM updates from Andrew Morton: - "mm/rmap: index MAP_PRIVATE file-backed folios by anonymous pgoff" (Lorenzo Stoakes) Index MAP_PRIVATE file-backed folios by their anonymous page offset to resolve confusion around reverse mapping for zeroed and CoW'd file-backed memory. Use this new VMA anonymous page offset tracking to eliminate index conflicts and lay the foundation for scalable CoW performance improvements. - "promote mapped executable folios after first usage for MGLRU" (Baolin Wang) Make MGLRU's protection of mapped executable file folios more reliable. Follow the classical LRU's logic, promoting mapped executable file folios after their first usage to give executable code a better chance to stay in memory and improve workload performance. - "mm: vmscan: fix node reclaim ignoring swappiness parameter" (Ridong Chen) Fix per-node proactive reclaim interface's ignoring the swappiness parameter when CONFIG_MEMCG is disabled by consolidating sc_swappiness() into a single function that checks proactive_swappiness regardless of kernel configuration. - "mm/vmscan: reduce lru_lock contention via vmstat-derived scan-balance cost" (Usama Arif) Reduce lru_lock contention in the reclaim path by deriving scan-balance costs from vmstat counters rather than lock-acquired producer updates. Read and decay these cost signals on the reclaim side under a dedicated per-lruvec lock, reducing total LRU lock wait time by over 60% without impacting scan throughput. - "zram: fix zram issues reported by sashiko" (Sergey Senozhatsky) Fix two low-risk zram bugs which Sashiko spotted in drive-by review. - "Honor XA_FLAGS_ACCOUNT in xas_split_alloc() and charge to folio's memcg" (Zi Yan) Fix xas_split_alloc() by enabling target folio memcg charging during splits and adding the missing __GFP_ACCOUNT flag for proper XArray node memory accounting. - "selftests/mm: use pattern matching in .gitignore" (Pratyush Mallick) Replace hardcoded binary names in selftests/mm/.gitignore with a generic pattern-matching rule to automatically ignore generated test files and avoid manual updates when adding new tests. - "mm/page_ext: remove pgdat_page_ext_init()" (Sang-Heon Jeon) Make the incompatibility between FLATMEM and NUMA explicit in mm/Kconfig and remove the unused pgdat_page_ext_init() function. - "zram: fix zstd error paths and add parameter validation" (Haoqin Huang) Clean up zram compression backends by removing redundant error cleanup, adding parameter and dictionary validation, auto-prefixing algorithm error logs, and resetting parameters prior to reinitialization. - "zram: fix stale scan bounds after reinitialization" (Longlong Xia) Prevent out-of-bounds slot accesses during concurrent zram resets by moving table scan bound calculations under dev_lock in writeback_store() and read_block_state(). - "add anon mTHP collapse test cases" (Baolin Wang) Extend selftests helper functions to support arbitrary page orders and add new test cases and options for mTHP collapse in khugepaged. - "selftests/mm: Handle unsupported and transient test conditions" (Muhammad Usama Anjum) Update MM selftests to report a SKIP status instead of a failure when required kernel or filesystem features are unsupported, while adding retry logic for transient page migration errors. - "mm/zswap: Fixes and improves the zswap shrink" (Hao Jia) Fix the missing zswap global shrinker when CONFIG_MEMCG is disabled and extend shrink_memcg() to support batch writeback for improved writeback efficiency. - "alloc_tag: introduce IOCTL-based filtering for MAP" (Suren Baghdasaryan) Introduce an IOCTL-based binary interface for memory allocation profiling that enables kernel-side filtering before per-CPU counter aggregation. This eliminates the text-parsing overhead of /proc/allocinfo and provides up to a 20x speedup by transferring only filtered allocation data to userspace. - "better block swap batching and a different take on swap_ops v5" (Christoph Hellwig) Refactor block swap I/O to use swap_iocb for batching instead of single-bio requests and rebase the swap_ops interface, achieving faster swap throughput during kernel builds. - "mm: kmemleak: reduce transient false positives by confirming leaks" (Catalin Marinas) Reduce false-positive kmemleak reports by combining two kmemleak enhancements that add a second confirmation scan and a configurable minimum unreferenced scan count module parameter. - "mm: kmemleak: default min_unref_scans to 2 for verbose kernels" (Breno Leitao) Auto-scanning kernels can generate false-positive memory leak reports on single scans, so this patch defaults min_unref_scans to 2 when CONFIG_DEBUG_KMEMLEAK_VERBOSE is enabled to require a second confirming scan. - "swap_ops updates" (Christoph Hellwig) Batching I/O for synchronous swap devices causes performance regressions and filesystem-based swap suffers from double-indirection overhead. This series resolves both issues by reintroducing per-folio writes for synchronous swap and allowing filesystems to directly export their own swap_ops. - "mm/khugepaged: several cleanups" (Nico Pache) khugepaged accumulated redundant state-checking patterns and outdated comments following mTHP integration. Introduce dedicated helpers for PTE validation and event counting while refreshing the internal documentation. - "maple_tree: lock checking and clean ups" (Liam Howlett) Syzbot reports incorrectly blame memory management exit paths for locking bugs, maple tree erase operations risk allocation failures without gfp flags and internal documentation lacks clarity. Improve lock error detection, update docs, fix race and allocation edge cases and optimize erase allocations using a fallback to GFP_KERNEL | GFP_NOFAIL. * tag 'mm-stable-2026-08-26-15-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (172 commits) selftests/proc: make proc-maps-race work with READ_IMPLIES_EXEC memcg: move LRU size accounting on reparenting instead of copying it mm/vmscan: fix comment logic in balance_pgdat maple_tree: add helper mas_make_walkable() maple_tree: avoid extra gap calculation maple_tree: fix argument name in header maple_tree: change two GFP flags in tests maple_tree: document erase and allocations better maple_tree: avoid mas_erase() and mtree_erase() failures maple_tree: document that erase may use GFP_KERNEL for allocations maple_tree: catch race in mas_alloc_cyclic() maple_tree: add bulk parent set helper maple_tree: micro optimisation of mas_wr_store_type() maple_tree: optimise mas_wr_node_store() when not in rcu mode maple_tree: use prefetched value in mas_wr_store_type() maple_tree: clarify comments on mas_nomem() maple_tree: drop MAPLE_ALLOC_SLOTS maple_tree: drop dead code from mas_extend_spanning_null() maple_tree: documentation fix maple_tree: add write lock checking with lockdep sequence numbers ...
2026-08-24mm/page_ext: remove pgdat_page_ext_init()Sang-Heon Jeon1-1/+0
pgdat_page_ext_init() sets pgdat->node_page_ext to NULL only on FLATMEM. FLATMEM depends on !NUMA, so the pgdat is always the zero-initialized contig_page_data and the store has no effect. So remove the call site, the unused function and its declaration. No functional change. Link: https://lore.kernel.org/20260804151145.3419768-3-ekffu200098@gmail.com Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com> Acked-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-08-23Merge tag 'liveupdate-v7.3-rc1-20260823' of ↵Linus Torvalds1-14/+15
git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux Pull more liveupdate updates from Mike Rapoport: "Make boot time huge page allocation work nicely with kexec handover. Today allocation of gigantic pages in HugeTLB cannot work reliably with kexec handover (KHO): - HugeTLB allocates gigantic pages using memblock and autoscaling of KHO scratch accounts for these allocations. When gigantic pages occupy half of the memory of more, KHO fails to allocate its scratch memory. - After kexec handover, memblock allocations exclusively use KHO scratch that is not supposed to contain preserved memory. This essentially blocks preservation of HugeTLB with gigantic pages. Extend early memory pools available for KHO kernel with areas that are guaranteed not to contain preserved memory" * tag 'liveupdate-v7.3-rc1-20260823' of git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux: (21 commits) kho: exclude hugetlb memory from scratch size calculation memblock: add memblock_reserved_hugetlb_size() memblock: make HugeTLB bootmem allocation work with KHO memblock: always include KHO headers kho: extend scratch mm/mm_init: don't rely on memblock to get KHO scratch migratetype kho: initialize preserved memory map radix tree earlier kho: initialize kho_scratch pointer earlier in boot kho: expose kho_scratch_overlap() to kexec_handover.h kho: add kho_radix_init_tree() kho: allow destroying KHO radix tree kho: allow early-boot usage of the KHO radix tree kho: add data argument to radix walk callback kho: add callback for table pages kho: add a struct for radix callbacks kho: move all memory retrieval logic to kho_mem_retrieve() kho: store incoming radix tree in kho_in kho: disallow wide keys in radix tree kho: make radix max key width more obvious kho: generalize radix tree APIs ...
2026-08-20Merge tag 'mm-stable-2026-08-18-18-39' of ↵Linus Torvalds1-53/+37
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 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 ...
2026-08-18Merge tag 'memblock-v7.3-rc1' of ↵Linus Torvalds1-70/+23
git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock Pull memblock updates from Mike Rapoport: "Non-urgent fixes: - Fix calculation of node_spanned_pages when running with 'kernelcore=mirror' - Properly handle failure to allocate per_cpu_nodestats in free_area_init_core_hotplug() - Fix deferred initialization of the memory map for configurations where node's RAM end is not aligned on PAGES_PER_SECTION Cleanups: - Remove redundant pageblock_align() call in free_unused_memmap() - Remove unnecessary invalid range checks in users of memblock iterators. Some users of for_each_mem_range() and for_each_mem_pfn_range() verify that start < end for each range. This is redundant because memblock iterators guarantee to never return an invalid range - Stop overlapping zones with 'kernelcore=mirror' and align behaviour of 'kernelcore=mirror' with other variants of kernelcore and movablecore - Remove redundant updates of numa_nodes_parsed mask in the callers of numa_add_memblk(), the latter always updates the mask anyway - Remove unnecessary initialization of pgdat->per_cpu_nodestats to NULL, the variable is reset to the actual value a few lines below" * tag 'memblock-v7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock: (25 commits) mm/mm_init: deferred_grow_zone(): fix out-of-range first_deferred_pfn mm/mm_init: remove unnecessary initialization of pgdat->per_cpu_nodestats mm/mm_init: remove redundant memset in free_area_init() mm: numa_memblks: use numa_add_reserved_memblk() in numa_cleanup_meminfo() arch_numa: remove redundant node_possible_map assignment mm: numa_memblks: remove redundant numa_nodemask_from_meminfo() LoongArch: remove redundant numa_nodes_parsed node_set() arch_numa: remove redundant numa_nodes_parsed node_set() x86/numa: remove redundant numa_nodes_parsed node_set() of/numa: remove redundant numa_nodes_parsed node_set() ACPI: NUMA: remove redundant numa_nodes_parsed node_set() mm: numa_memblks: set numa_nodes_parsed in numa_add_memblk() mm/mm_init: handle alloc_percpu failure in free_area_init_core_hotplug mm/mm_init: drop overlap_memmap_init() mm/mm_init: don't overlap NORMAL and MOVABLE zones with kernelcore=mirror mm/hugetlb: remove unnecessary empty range check in hugetlb_bootmem_set_nodes() mm: remove unnecessary empty range check in early_calculate_totalpages() powerpc64/kasan: Remove unreachable invalid range check in kasan_init_phys_region() ARM: remove unreachable invalid range check in kasan_init() riscv: remove unreachable invalid range check in kasan_init() ...
2026-08-07Merge branch 'misc' into for-nextMike Rapoport (Microsoft)1-2/+0
2026-08-07Merge branch 'range-checks' into for-nextMike Rapoport (Microsoft)1-2/+1
2026-08-07Merge branch 'kernelcore-mirror' into for-nextMike Rapoport (Microsoft)1-57/+3
2026-08-07mm/mm_init: deferred_grow_zone(): fix out-of-range first_deferred_pfnAlexander Graf1-3/+6
With CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled, deferred_grow_zone() initializes struct pages early in boot to satisfy an allocation. With a large CMA reservation in place, the ranges deferred_init_memmap() finds may not add up to the allocation it was asked for, and the function ends up initializing the memory map of the entire zone and still falls short. That is fine in itself: the function accounts for it and leaves the caller to decide whether it now has enough memory. However, the update of pgdat->first_deferred_pfn that tracks where uninitialized memory map starts could overflow. If the node's RAM end is not aligned on PAGES_PER_SECTION boundaries and some deferred struct pages were initialized, pgdat->first_deferred_pfn would point past the end of the node's memory. deferred_init_memmap() later picks up from pgdat->first_deferred_pfn and hits a BUG_ON(), because it expects a pfn within its node. For example, when running a kernel with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y and CONFIG_CMA=y using the following qemu command line qemu-system-x86_64 -enable-kvm -m 8032M -kernel bzImage \ -append "nokaslr cma=4768M@0x100000000" the kernel panics: kernel BUG at mm/mm_init.c:2131! CPU: 3 UID: 0 PID: 36 Comm: pgdatinit0 Not tainted 7.2.0-rc6 #1 RIP: 0010:deferred_init_memmap+0x1b8/0x1c0 RAX: 0000000000236000 R13: 0000000000238000 Call Trace: kthread+0xdf/0x120 ret_from_fork+0x187/0x250 Make sure that the update of pgdta->first_deferred_pfn does not overflow when the entire zone's (and therefore node's) memory map is initialized. Fixes: 3acb913c9d5b ("mm/mm_init: use deferred_init_memmap_chunk() in deferred_grow_zone()") Cc: stable@vger.kernel.org Assisted-by: Kiro:claude-opus-5 Signed-off-by: Alexander Graf <graf@amazon.com> Link: https://patch.msgid.link/20260807031243.87904-1-graf@amazon.com [rppt: massaged the changelog] Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-08-04mm: split out vmalloc declarations from internal.hMike Rapoport (Microsoft)1-0/+1
mm/internal.h becomes more and more bloated. Move declarations related to vmalloc to a new mm/vmalloc.h header. No functional changes. Link: https://lore.kernel.org/20260709-internal-h-v2-3-695631425968@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Muchun Song <muchun.song@linux.dev> Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: Pratyush Yadav <pratyush@kernel.org> Acked-by: SJ Park <sj@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Alexander Potapenko <glider@google.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Brendan Jackman <brendan.jackman@linux.dev> Cc: Dennis Zhou <dennis@kernel.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Marco Elver <elver@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-08-04mm: split out sparse declarations from internal.hMike Rapoport (Microsoft)1-0/+1
mm/internal.h becomes more and more bloated. Move declarations related to SPARSE and SPARSE_VMEMMAP memory models to a new mm/sparse.h header. No functional changes. Link: https://lore.kernel.org/20260709-internal-h-v2-2-695631425968@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Muchun Song <muchun.song@linux.dev> Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: Pratyush Yadav <pratyush@kernel.org> Acked-by: SJ Park <sj@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Alexander Potapenko <glider@google.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Brendan Jackman <brendan.jackman@linux.dev> Cc: Dennis Zhou <dennis@kernel.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Marco Elver <elver@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-08-04mm: split out mm_init and memblock declarations from internal.hMike Rapoport (Microsoft)1-0/+1
Patch series "mm: split a couple of headers from internal.h", v2. mm/internal.h becomes more and more bloated. Split declarations related to mm_init, memblock, vmalloc and sparse into new headers. This patch (of 3): mm/internal.h becomes more and more bloated. Move declarations for related to mm/mm_init.c and mm/memblock.c to a new mm/mm_init.h header. No functional changes. [rppt@kernel.org: split stubfs from internal.h to mm_init.h] Link: https://lore.kernel.org/alJd1BLypyK9Mpaw@kernel.org Link: https://lore.kernel.org/20260709-internal-h-v2-0-695631425968@kernel.org Link: https://lore.kernel.org/20260709-internal-h-v2-1-695631425968@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Muchun Song <muchun.song@linux.dev> Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: Pratyush Yadav <pratyush@kernel.org> Acked-by: SJ Park <sj@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Alexander Potapenko <glider@google.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Brendan Jackman <brendan.jackman@linux.dev> Cc: Dennis Zhou <dennis@kernel.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Marco Elver <elver@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-08-04mm/mm_init: don't rely on memblock to get KHO scratch migratetypePratyush Yadav (Google)1-14/+13
Currently struct page init via memmap_init() or deferred_init_memmap() only queries the migrate type from KHO for each discrete memory range. That works currently since KHO scratch memory has a different memory type so it is always it its own region. An upcoming patch will add support for discovering blocks of memory with no preservations and it will mark it as MEMBLOCK_KHO_SCRATCH to allow allocations from them. This can lead to the bootmem KHO scratch areas to be merged into larger free ranges. This merging breaks the selection of migrate type. Get rid of memblock_is_kho_scratch_memory(). Instead, use kho_scratch_overlap() to decide the migrate type of the PFN. Since kho_scratch_migratetype() only uses KHO functions, move it to kexec_handover.h. Instead of calling kho_scratch_migratetype() once for each free range, call it once for each pageblock. Update pageblock_migratetype_init_range() and memmap_init_range() to do so. Since the migrate type is now evaluated for each pageblock and not each free range, drop the migratetype arguments to deferred_free_pages() and memmap_init_zone_range() and use MIGRATE_MOVABLE directly. Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org> Link: https://patch.msgid.link/20260801084833.1897543-18-pratyush@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-08-04kho: initialize kho_scratch pointer earlier in bootPratyush Yadav (Google)1-0/+2
In a future patch, mm init will use kho_scratch_overlap() for deciding the migrate type of pageblocks it initializes. The earliest user currently is free_area_init(). kho_scratch_overlap() relies on kho_scratch pointer being initialized. Introduce kho_memory_init_early() to do this. kho_populate() would normally be a good place to do this, but unfortunately, phys_to_virt() does not work at that point on ARM64. So we need yet another initialization function. Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org> Link: https://patch.msgid.link/20260801084833.1897543-15-pratyush@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-07-30mm: split out internal page_alloc.hBrendan Jackman1-0/+1
internal.h is a bit bloated, seems like time for a page_alloc.h. Where it wasn't obvious, the heuristic for deciding what goes into this new header was "does it support/correspond to a definition in mm/page_alloc.c?" Only need to include it from ~20 .c files out of ~150 so this does seem like a genuine reduction in scopes, which is nice. And there's no circular internal.h<->page_alloc.h dependency, so it seems worthwhile to split this up before that inevitably emerges! Link: https://lore.kernel.org/20260703-alloc-trylock-v5-4-c87b714e19d3@google.com Signed-off-by: Brendan Jackman <jackmanb@google.com> Suggested-by: "David Hildenbrand (Arm)" <david@kernel.org> Link: https://lore.kernel.org/all/41e92bab-6882-401a-8de9-154adbdcfb36@kernel.org/ Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Acked-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-30mm/mm_init: handle alloc_percpu failure in free_area_init_core_hotplugGregory Price1-3/+11
We miss a failed allocation check for pgdat->per_cpu_nodestats, which results in a NULL deref when we offset into the per-cpu area. Propagate -ENOMEM up the stack and leave per_cpu_nodestats pointing at boot_nodestats so a later online can retry the allocation. hotadd_init_pgdat() returns NULL on failure, which __try_online_node() already maps to -ENOMEM. On failure nothing needs to be unwound: - the node is never marked online - per_cpu_nodestats is left pointing at boot_nodestats - __add_memory_resource() cleans up pending memblock resources - later online attempts retry the per_cpu_nodestats allocation Link: https://lore.kernel.org/20260701221613.2818148-1-gourry@gourry.net Fixes: 75ef71840539 ("mm, vmstat: add infrastructure for per-node vmstats") Signed-off-by: Gregory Price <gourry@gourry.net> Reported-by: Sashiko <sashiko-bot@kernel.org> Link: https://sashiko.dev/#/patchset/20260627202243.758289-1-gourry%40gourry.net Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Rapoport <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-30mm/mm_init: remove unnecessary initialization of pgdat->per_cpu_nodestatsSang-Heon Jeon1-1/+0
free_area_init_node() sets pgdat->per_cpu_nodestats to NULL and later calls free_area_init_core(), which unconditionally overwrites it with &boot_nodestats. Nothing reads the field in between, so the store has no effect. Remove unnecessary initialization. No functional change. Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com> Link: https://patch.msgid.link/20260729155143.177790-1-ekffu200098@gmail.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-07-28mm/mm_init: fold __init_page_from_nid() into __init_deferred_page()Muchun Song1-26/+16
__init_page_from_nid() no longer has external users and is only used locally in mm/mm_init.c under CONFIG_DEFERRED_STRUCT_PAGE_INIT. Fold it into its sole caller __init_deferred_page() and remove the separate helper declaration. Link: https://lore.kernel.org/20260612035903.2468601-20-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@kernel.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Oscar Salvador (SUSE) <osalvador@kernel.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-28mm/sparse: move sparse_vmemmap_init_nid_late() into sparse_init_nid()Muchun Song1-4/+0
sparse_vmemmap_init_nid_late() is still called separately from mm_core_init_early(), away from the rest of the sparse initialization path. Now that sparse_init() runs after zone initialization, call sparse_vmemmap_init_nid_late() from sparse_init_nid() instead. This keeps both sparse_vmemmap_init_nid_early() and sparse_vmemmap_init_nid_late() in the sparse setup path. Link: https://lore.kernel.org/20260612035903.2468601-12-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Oscar Salvador (SUSE) <osalvador@kernel.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@kernel.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-28mm/mm_init: remove set_pageblock_order() call from sparse_init()Muchun Song1-2/+2
free_area_init() already sets pageblock_order before sparse_init() runs for CONFIG_HUGETLB_PAGE_SIZE_VARIABLE, so sparse_init() does not need to call set_pageblock_order() again. With that call removed, set_pageblock_order() is only used in mm/mm_init.c. Make it static. Link: https://lore.kernel.org/20260612035903.2468601-11-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Oscar Salvador (SUSE) <osalvador@suse.de> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@kernel.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador (SUSE) <osalvador@kernel.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-28mm/mm_init: defer hugetlb reservation until after zone initializationMuchun Song1-2/+2
hugetlb_cma_reserve() and hugetlb_bootmem_alloc() currently run before free_area_init(), so HugeTLB reservation happens before zone state is initialized. Move the reservation step after free_area_init() so the relevant zone information is available before HugeTLB reserves memory. This is needed for later hugetlb changes that validate boot-time HugeTLB reservations against zone boundaries. Link: https://lore.kernel.org/20260612035903.2468601-10-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Oscar Salvador (SUSE) <osalvador@kernel.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@kernel.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-28mm/mm_init: defer sparse_init() until after zone initializationMuchun Song1-5/+7
free_area_init() is responsible for initializing pgdat and zone state. Calling sparse_init() from there mixes in later vmemmap and struct page setup, which makes the initialization flow less clear. Defer sparse_init(), sparse_vmemmap_init_nid_late(), and memmap_init() until after free_area_init() completes, when zone initialization is fully done. This keeps free_area_init() focused on zone setup and ensures that sparse_init() runs with the relevant zone state already available. This is also a prerequisite for later hugetlb vmemmap changes that need zone information during early sparse vmemmap setup. Link: https://lore.kernel.org/20260612035903.2468601-9-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Oscar Salvador (SUSE) <osalvador@kernel.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@kernel.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-28mm/sparse: move subsection_map_init() into sparse_init()Muchun Song1-8/+2
subsection_map_init() is part of sparse memory initialization, but it is currently called from free_area_init(). Move it into sparse_init() so the sparse-specific setup stays together instead of being split across the generic free_area_init() path. Link: https://lore.kernel.org/20260612035903.2468601-8-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Oscar Salvador <osalvador@suse.de> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@kernel.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador (SUSE) <osalvador@kernel.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-28mm/mm_init: simplify deferred_free_pages() migratetype initMuchun Song1-11/+8
deferred_free_pages() open-codes two loops to initialize the pageblock migratetype for a range of pages. Replace them with pageblock_migratetype_init_range() to remove the duplication and make the code clearer (Note that deferred_free_pages() may be called from atomic context). Link: https://lore.kernel.org/20260612035903.2468601-6-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Oscar Salvador <osalvador@suse.de> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@kernel.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador (SUSE) <osalvador@kernel.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-28mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlierMuchun Song1-0/+1
Gigantic bootmem HugeTLB pages are currently initialized from hugetlb_init(), but page_alloc_init_late() runs earlier and walks pageblocks to determine zone contiguity. If a bootmem HugeTLB region is marked noinit, set_zone_contiguous() can observe still-uninitialized struct pages through __pageblock_pfn_to_page(). This may not trigger an immediate failure, but it can make set_zone_contiguous() compute the wrong zone contiguity state. If extra poisoned-page checks are added in this path, such as PF_POISONED_CHECK() in page_zone_id(), it can also trigger an early boot panic. Initialize gigantic bootmem HugeTLB struct pages from page_alloc_init_late(), before zone contiguity is evaluated, so later page allocator setup only sees valid struct page state. This also makes the initialization order more natural, as struct pages should be initialized before later code inspects them. Link: https://lore.kernel.org/20260612035903.2468601-5-songmuchun@bytedance.com Fixes: fde1c4ecf916 ("mm: hugetlb: skip initialization of gigantic tail struct pages if freed by HVO") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Oscar Salvador <osalvador@suse.de> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@kernel.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador (SUSE) <osalvador@kernel.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-22mm/mm_init: remove redundant memset in free_area_init()Sang-Heon Jeon1-1/+0
zone_movable_pfn is zero-initialized and only set by find_zone_movable_pfns_for_nodes(), which runs once during boot right after the memset, so the memset has no effect. Remove redundant memset. No functional change. Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com> Link: https://patch.msgid.link/20260720150915.756749-1-ekffu200098@gmail.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-07-20mm/vmstat: fold stranded per-cpu node stats when a node comes onlineGregory Price1-4/+11
A per-node vmstat counter is pgdat->vm_stat[] plus per-cpu deltas. A balanced counter can sit split as global=+N / per-cpu=-N. The folds reconciling the split only walk online nodes, so when try_offline_node() marks a node offline the per-cpu deltas are stranded. A subsequent online resets the per-cpu area but not pgdat->vm_stat[], orphaning the +N permanently. All NR_VM_NODE_STAT_ITEMS are affected. The existing code zeroes the per-cpu counters and causes a permanent skew. Fold the stranded deltas instead, before the node rejoins the online set. The node is not online yet and the hotplug lock is held, so the remote access to per-cpu values is safe. Discovered when node compaction hung for a nearly empty node, as the math to determine throttling broke. Reproduced by repeated memory hotplug/unplug cycles on a node under pressure: NR_ISOLATED_ANON ratchets up and never returns to zero. Link: https://lore.kernel.org/20260627202243.758289-1-gourry@gourry.net Fixes: 75ef71840539 ("mm, vmstat: add infrastructure for per-node vmstats") Signed-off-by: Gregory Price <gourry@gourry.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Rapoport <rppt@kernel.org> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-07-02mm/mm_init: handle alloc_percpu failure in free_area_init_core_hotplugGregory Price1-3/+11
We miss a failed allocation check for pgdat->per_cpu_nodestats, which results in a NULL deref when we offset into the per-cpu area. Propagate -ENOMEM up the stack and leave per_cpu_nodestats pointing at boot_nodestats so a later online can retry the allocation. hotadd_init_pgdat() returns NULL on failure, which __try_online_node() already maps to -ENOMEM. On failure nothing needs to be unwound: - the node is never marked online - per_cpu_nodestats is left pointing at boot_nodestats - __add_memory_resource() cleans up pending memblock resources - later online attempts retry the per_cpu_nodestats allocation Reported-by: Sashiko <sashiko-bot@kernel.org> Link: https://sashiko.dev/#/patchset/20260627202243.758289-1-gourry%40gourry.net Fixes: 75ef71840539 ("mm, vmstat: add infrastructure for per-node vmstats") Signed-off-by: Gregory Price <gourry@gourry.net> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Link: https://patch.msgid.link/20260701221613.2818148-1-gourry@gourry.net Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-07-02Merge patch series "mm/mm_init: don't overlap zones with kernelcore=mirror"Mike Rapoport (Microsoft)1-57/+3
Mike Rapoport <rppt@kernel.org> says: Make the behaviour of kernelcore= parameter uniform and treat mirror just as another way to size the zones and cleanup a weird part of the memory map initialization. For example, for the memory layout below with the first two memory ranges being mirrored (flags=0x2) memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x2 memory[0x1] [0x0000000000100000-0x00000000bffdefff], 0x00000000bfedf000 bytes on node 0 flags: 0x2 memory[0x2] [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x2 memory[0x3] [0x0000000140000000-0x00000001bfffffff], 0x0000000080000000 bytes on node 0 flags: 0x0 with kernelcore=mirror set zone ranges would be Normal [100000, 1c0000] Movable [140000, 1c0000] and range [140000, 1c0000] is spanned by both NORMAL and MOVABLE zones. This range will be passed twice to memmap_init_range() - once for each zone that spans it. The memory map for this range will be initialized as ZONE_NORMAL during the first pass and skipped because of overlap_memmap_init() during the second pass (ZONE_MOVABLE initialization), although the pages in this range actually belong to ZONE_MOVABLE. Aligning kernelcore=mirror behaviour with other variants of kernelcore=/movablecore= resolves this issue and makes the code less obfuscated. patches from https://patch.msgid.link/20260630072212.624305-1-rppt@kernel.org mm/mm_init: don't overlap NORMAL and MOVABLE zones with kernelcore=mirror mm/mm_init: drop overlap_memmap_init() Link: https://patch.msgid.link/20260630072212.624305-1-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-07-02mm/mm_init: drop overlap_memmap_init()Mike Rapoport (Microsoft)1-24/+0
When ZONE_NORMAL and ZONE_MOVABLE could overlap because kernelcore=mirror didn't reduce the span of ZONE_NORMAL, initialization of the memory map had to skip overlapping pages during initialization of ZONE_MOVABLE to avoid double initialization of the same struct pages. Since kernelcore=mirror works now the same way as other variants of kernelcore=/movablecore=, and adjusts the span of ZONE_NORMAL, there can't be an overlap between ZONE_NORMAL and ZONE_MOVABLE. Remove overlap_memmap_init(). Co-developed-by: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: David Hildenbrand (Arm) <david@kernel.org> Link: https://patch.msgid.link/20260630072212.624305-3-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
2026-07-02mm/mm_init: don't overlap NORMAL and MOVABLE zones with kernelcore=mirrorMike Rapoport (Microsoft)1-33/+3
When kernelcore or movablecore kernel parameters define size of the NORMAL and MOVABLE zones as percents of the total memory or by absolute value, ZONE_NORMAL is clamped at the beginning of ZONE_MOVABLE. However, when kernelcore=mirror the ZONE_NORMAL span is not changed but rather pages from ZONE_MOVABLE counted as absent in ZONE_NORMAL. Make the behaviour of kernelcore= parameter uniform and treat mirror just as another way to size the zones. Co-developed-by: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Link: https://patch.msgid.link/20260630072212.624305-2-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
2026-07-01mm: remove unnecessary empty range check in early_calculate_totalpages()Sang-Heon Jeon1-2/+1
early_calculate_totalpages() iterates the memory ranges with for_each_mem_pfn_range() and calls node_set_state(nid, N_MEMORY) only when end_pfn - start_pfn is non-zero. for_each_mem_pfn_range() never returns an empty range, so start_pfn < end_pfn always. Therefore the check is unnecessary, so remove it. No functional change. Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Link: https://patch.msgid.link/20260630150413.1718632-8-ekffu200098@gmail.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-30mm/mm_init: fix incorrect node_spanned_pagesWei Yang1-3/+2
Current node_spanned_pages is got as a summation of all zone's spanned page in calculate_node_totalpages(). Generally this is good, but if we use kernelcore=mirror, it is would be wrong. Without kernelcore=mirror: The test machine has below memory layout: memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0 memory[0x1] [0x0000000000100000-0x00000000bffdefff], 0x00000000bfedf000 bytes on node 0 flags: 0x0 memory[0x2] [0x0000000100000000-0x00000001bfffffff], 0x00000000c0000000 bytes on node 0 flags: 0x0 And the Zone range is: DMA [mem 0x0000000000001000-0x0000000000ffffff] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] Normal [mem 0x0000000100000000-0x00000001bfffffff] Then we see, with spanned_pages printed: On node 0 spanned_pages: 1835007 totalpages: 1572733 With kernelcore=mirror: The test machine has below memory layout: memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x2 memory[0x1] [0x0000000000100000-0x00000000bffdefff], 0x00000000bfedf000 bytes on node 0 flags: 0x2 memory[0x2] [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x2 memory[0x3] [0x0000000140000000-0x00000001bfffffff], 0x0000000080000000 bytes on node 0 flags: 0x0 And the Zone range is: DMA [mem 0x0000000000001000-0x0000000000ffffff] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] Normal [mem 0x0000000100000000-0x00000001bfffffff] Device empty Movable zone start for each node Node 0: 0x0000000140000000 Then we see, with spanned_pages printed: On node 0 spanned_pages: 2359295 totalpages: 1572733 The total range of memory on node 0 doesn't change, but the spanned_pages becomes much larger. The reason is when kernelcore=mirror is specified, the range of Zone Normal and Zone Movable would overlap. So the overlapped range would be calculated twice. A wrong node_spanned_pages would effect defer_init(), since each zone_end_pfn is less than pgdat_end_pfn(). As we already passed in node_start_pfn and node_end_pfn, fix this by get it from (node_start_pfn - node_end_pfn) directly. Fixes: 342332e6a925 ("mm/page_alloc.c: introduce kernelcore=mirror option") Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Cc: Yuan Liu <yuan1.liu@intel.com> Link: https://patch.msgid.link/20260622022403.16375-1-richard.weiyang@gmail.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-21Merge tag 'liveupdate-v7.2-rc1' of ↵Linus Torvalds1-13/+17
git://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux 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 ...
2026-06-19Merge tag 'mm-stable-2026-06-18-09-26' of ↵Linus Torvalds1-37/+36
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 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 ...
2026-06-17Merge tag 'memblock-v7.2-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock 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
2026-06-08mm: switch deferred split shrinker to list_lruJohannes Weiner1-15/+0
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 <hannes@cmpxchg.org> Reported-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Tested-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Acked-by: Usama Arif <usama.arif@linux.dev> Reviewed-by: Kairui Song <kasong@tencent.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: David Hildenbrand (Arm) <david@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam R. Howlett <liam@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nico Pache <npache@redhat.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-02mm: introduce for_each_free_list()Brendan Jackman1-4/+7
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 <jackmanb@google.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kairui Song <kasong@tencent.com> Cc: Len Brown <lenb@kernel.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-02mm: Make empty_zero_page[] constArd Biesheuvel1-1/+1
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) <rppt@kernel.org> Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Jann Horn <jannh@google.com> Reviewed-by: Feng Tang <feng.tang@linux.alibaba.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
2026-06-02mm: mm_init: use div64_ul() instead of do_div()Giorgi Tchankvetadze1-1/+1
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 <giorgitchankvetadze1997@gmail.com> Link: https://patch.msgid.link/20260602-mm-div64-cleanup-v1-1-bf5d67d89d93@gmail.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-01kho: fix deferred initialization of scratch areasMichal Clapinski1-13/+17
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) <rppt@kernel.org> Signed-off-by: Michal Clapinski <mclapinski@google.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Link: https://patch.msgid.link/20260423122538.140993-2-mclapinski@google.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-05-28mm/mm_init: fix uninitialized struct pages for ZONE_DEVICEMuchun Song1-3/+10
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 <songmuchun@bytedance.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Liam R. Howlett <liam@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28mm/mm_init: fix pageblock migratetype for ZONE_DEVICE compound pagesMuchun Song1-15/+19
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 <songmuchun@bytedance.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Liam R. Howlett <liam@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-04-18Merge tag 'memblock-v7.1-rc1' of ↵Linus Torvalds1-25/+0
git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock Pull memblock updates from Mike Rapoport: - improve debuggability of reserve_mem kernel parameter handling with print outs in case of a failure and debugfs info showing what was actually reserved - Make memblock_free_late() and free_reserved_area() use the same core logic for freeing the memory to buddy and ensure it takes care of updating memblock arrays when ARCH_KEEP_MEMBLOCK is enabled. * tag 'memblock-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock: x86/alternative: delay freeing of smp_locks section memblock: warn when freeing reserved memory before memory map is initialized memblock, treewide: make memblock_free() handle late freeing memblock: make free_reserved_area() update memblock if ARCH_KEEP_MEMBLOCK=y memblock: extract page freeing from free_reserved_area() into a helper memblock: make free_reserved_area() more robust mm: move free_reserved_area() to mm/memblock.c powerpc: opal-core: pair alloc_pages_exact() with free_pages_exact() powerpc: fadump: pair alloc_pages_exact() with free_pages_exact() memblock: reserve_mem: fix end caclulation in reserve_mem_release_by_name() memblock: move reserve_bootmem_range() to memblock.c and make it static memblock: Add reserve_mem debugfs info memblock: Print out errors on reserve_mem parser
2026-04-05mm: mark early-init static variables with __meminitdataKaitao Cheng1-1/+1
Static variables defined inside __meminit functions should also be marked with __meminitdata, so that their storage is placed in the .init.data section and reclaimed with free_initmem(), thereby reducing permanent .bss memory usage when CONFIG_MEMORY_HOTPLUG is disabled. Link: https://lkml.kernel.org/r/20260321120847.8159-1-pilgrimtao@gmail.com Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Hildenbrand <david@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-04-05mm: prepare to move subsection_map_init() to mm/sparse-vmemmap.cDavid Hildenbrand (Arm)1-1/+1
We want to move subsection_map_init() to mm/sparse-vmemmap.c. To prepare for getting rid of subsection_map_init() in mm/sparse.c completely, use a static inline function for !CONFIG_SPARSEMEM_VMEMMAP. While at it, move the declaration to internal.h and rename it to "sparse_init_subsection_map()". Link: https://lkml.kernel.org/r/20260320-sparsemem_cleanups-v2-11-096addc8800d@kernel.org Signed-off-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-04-05mm: change the interface of prep_compound_tail()Kiryl Shutsemau1-1/+1
Instead of passing down the head page and tail page index, pass the tail and head pages directly, as well as the order of the compound page. This is a preparation for changing how the head position is encoded in the tail page. Link: https://lkml.kernel.org/r/20260227194302.274384-3-kas@kernel.org Signed-off-by: Kiryl Shutsemau <kas@kernel.org> Reviewed-by: Muchun Song <muchun.song@linux.dev> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand (arm) <david@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Baoquan He <bhe@redhat.com> Cc: Christoph Lameter <cl@gentwo.org> Cc: David Rientjes <rientjes@google.com> Cc: Frank van der Linden <fvdl@google.com> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Usama Arif <usamaarif642@gmail.com> Cc: WANG Xuerui <kernel@xen0n.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-04-05mm: cache struct page for empty_zero_page and return it from ZERO_PAGE()Mike Rapoport (Microsoft)1-4/+17
For most architectures every invocation of ZERO_PAGE() does virt_to_page(empty_zero_page). But empty_zero_page is in BSS and it is enough to get its struct page once at initialization time and then use it whenever a zero page should be accessed. Add yet another __zero_page variable that will be initialized as virt_to_page(empty_zero_page) for most architectures in a weak arch_setup_zero_pages() function. For architectures that use colored zero pages (MIPS and s390) rename their setup_zero_pages() to arch_setup_zero_pages() and make it global rather than static. For architectures that cannot use virt_to_page() for BSS (arm64 and sparc64) add override of arch_setup_zero_pages(). Link: https://lkml.kernel.org/r/20260211103141.3215197-5-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Andreas Larsson <andreas@gaisler.com> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Christophe Leroy (CS GROUP) <chleroy@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guo Ren <guoren@kernel.org> Cc: Helge Deller <deller@gmx.de> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Magnus Lindholm <linmag7@gmail.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-04-05arch, mm: consolidate empty_zero_pageMike Rapoport (Microsoft)1-0/+5
Reduce 22 declarations of empty_zero_page to 3 and 23 declarations of ZERO_PAGE() to 4. Every architecture defines empty_zero_page that way or another, but for the most of them it is always a page aligned page in BSS and most definitions of ZERO_PAGE do virt_to_page(empty_zero_page). Move Linus vetted x86 definition of empty_zero_page and ZERO_PAGE() to the core MM and drop these definitions in architectures that do not implement colored zero page (MIPS and s390). ZERO_PAGE() remains a macro because turning it to a wrapper for a static inline causes severe pain in header dependencies. For the most part the change is mechanical, with these being noteworthy: * alpha: aliased empty_zero_page with ZERO_PGE that was also used for boot parameters. Switching to a generic empty_zero_page removes the aliasing and keeps ZERO_PGE for boot parameters only * arm64: uses __pa_symbol() in ZERO_PAGE() so that definition of ZERO_PAGE() is kept intact. * m68k/parisc/um: allocated empty_zero_page from memblock, although they do not support zero page coloring and having it in BSS will work fine. * sparc64 can have empty_zero_page in BSS rather allocate it, but it can't use virt_to_page() for BSS. Keep it's definition of ZERO_PAGE() but instead of allocating it, make mem_map_zero point to empty_zero_page. * sh: used empty_zero_page for boot parameters at the very early boot. Rename the parameters page to boot_params_page and let sh use the generic empty_zero_page. * hexagon: had an amusing comment about empty_zero_page /* A handy thing to have if one has the RAM. Declared in head.S */ that unfortunately had to go :) Link: https://lkml.kernel.org/r/20260211103141.3215197-4-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Helge Deller <deller@gmx.de> [parisc] Tested-by: Helge Deller <deller@gmx.de> [parisc] Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Magnus Lindholm <linmag7@gmail.com> [alpha] Acked-by: Dinh Nguyen <dinguyen@kernel.org> [nios2] Acked-by: Andreas Larsson <andreas@gaisler.com> [sparc] Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: David S. Miller <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guo Ren <guoren@kernel.org> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-04-05mm: rename my_zero_pfn() to zero_pfn()Mike Rapoport (Microsoft)1-5/+5
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) <rppt@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Andreas Larsson <andreas@gaisler.com> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy (CS GROUP) <chleroy@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guo Ren <guoren@kernel.org> Cc: Helge Deller <deller@gmx.de> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Magnus Lindholm <linmag7@gmail.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>