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2026-01-26mm/page_table_check: reinstate address parameter in ↵Rohan McLure
[__]page_table_check_pmd[s]_set() This reverts commit a3b837130b58 ("mm/page_table_check: remove unused parameter in [__]page_table_check_pmd_set"). Reinstate previously unused parameters for the purpose of supporting powerpc platforms, as many do not encode user/kernel ownership of the page in the pte, but instead in the address of the access. Apply this to __page_table_check_pmds_set(), page_table_check_pmd_set(), and the page_table_check_pmd_set() wrapper macro. [ajd@linux.ibm.com: rebase on arm64 + riscv changes, update commit message] Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-4-755bc151a50b@linux.ibm.com Signed-off-by: Rohan McLure <rmclure@linux.ibm.com> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Acked-by: Ingo Molnar <mingo@kernel.org> # x86 Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Donet Tom <donettom@linux.ibm.com> Cc: Guo Weikang <guoweikang.kernel@gmail.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Magnus Lindholm <linmag7@gmail.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Cc: Thomas Huth <thuth@redhat.com> Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/page_table_check: reinstate address parameter in ↵Rohan McLure
[__]page_table_check_pud[s]_set() This reverts commit 6d144436d954 ("mm/page_table_check: remove unused parameter in [__]page_table_check_pud_set"). Reinstate previously unused parameters for the purpose of supporting powerpc platforms, as many do not encode user/kernel ownership of the page in the pte, but instead in the address of the access. Apply this to __page_table_check_puds_set(), page_table_check_puds_set() and the page_table_check_pud_set() wrapper macro. [ajd@linux.ibm.com: rebase on riscv + arm64 changes, update commit message] Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-3-755bc151a50b@linux.ibm.com Signed-off-by: Rohan McLure <rmclure@linux.ibm.com> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Acked-by: Ingo Molnar <mingo@kernel.org> # x86 Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Donet Tom <donettom@linux.ibm.com> Cc: Guo Weikang <guoweikang.kernel@gmail.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Magnus Lindholm <linmag7@gmail.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Cc: Thomas Huth <thuth@redhat.com> Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26arm64/mm: add addr parameter to __ptep_get_and_clear_anysz()Andrew Donnellan
To provide support for page table check on powerpc, we need to reinstate the address parameter in several functions, including page_table_check_{pte,pmd,pud}_clear(). In preparation for this, add the addr parameter to arm64's __ptep_get_and_clear_anysz() and change its callsites accordingly. Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-2-755bc151a50b@linux.ibm.com Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Donet Tom <donettom@linux.ibm.com> Cc: Guo Weikang <guoweikang.kernel@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Magnus Lindholm <linmag7@gmail.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Rohan McLure <rmclure@linux.ibm.com> Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Cc: Thomas Huth <thuth@redhat.com> Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26arm64/mm: add addr parameter to __set_ptes_anysz()Andrew Donnellan
Patch series "Support page table check on PowerPC", v18. Support page table check on PowerPC. Page table check tracks the usage of of page table entries at each level to ensure that anonymous mappings have at most one writable consumer, and likewise that file-backed mappings are not simultaneously also anonymous mappings. In order to support this infrastructure, a number of helpers or stubs must be defined or updated for all powerpc platforms. Additionally, we separate set_pte_at() and set_pte_at_unchecked(), to allow for internal, uninstrumented mappings. On some PowerPC platforms, implementing {pte,pmd,pud}_user_accessible_page() requires the address. We revert previous changes that removed the address parameter from various interfaces, and add it to some other interfaces, in order to allow this. For now, we don't allow page table check alongside HUGETLB_PAGE, due to the arch-specific complexity of set_huge_page_at(). (I'm sure I could figure this out, but I have to get this version on this list before I leave my job.) This series was initially written by Rohan McLure, who has left IBM and is no longer working on powerpc. This patch (of 18): To provide support for page table check on powerpc, we need to reinstate the address parameter in several functions, including page_table_check_{ptes,pmds,puds}_set(). In preparation for this, add the addr parameter to arm64's __set_ptes_anysz() and change its callsites accordingly. Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-0-755bc151a50b@linux.ibm.com Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-1-755bc151a50b@linux.ibm.com Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Alistair Popple <apopple@nvidia.com> Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Donet Tom <donettom@linux.ibm.com> Cc: Guo Weikang <guoweikang.kernel@gmail.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Magnus Lindholm <linmag7@gmail.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Cc: Thomas Huth <thuth@redhat.com> Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Ingo Molnar <mingo@kernel.org> Cc: Rohan McLure <rmclure@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26migrate: replace RMP_ flags with TTU_ flagsMatthew Wilcox (Oracle)
Instead of translating between RMP_ and TTU_ flags, remove the RMP_ flags and just use the TTU_ flag space; there's plenty available. Possibly we should rename these to RMAP_ flags, and maybe even pass them in through rmap_walk_arg, but that can be done later. Link: https://lkml.kernel.org/r/20260109041345.3863089-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Gregory Price <gourry@gourry.net> Cc: Jann Horn <jannh@google.com> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Ying Huang <ying.huang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/mempolicy: fix mpol_rebind_nodemask() for MPOL_F_NUMA_BALANCINGJinjiang Tu
commit bda420b98505 ("numa balancing: migrate on fault among multiple bound nodes") adds new flag MPOL_F_NUMA_BALANCING to enable NUMA balancing for MPOL_BIND memory policy. When the cpuset of tasks changes, the mempolicy of the task is rebound by mpol_rebind_nodemask(). When MPOL_F_STATIC_NODES and MPOL_F_RELATIVE_NODES are both not set, the behaviour of rebinding should be same whenever MPOL_F_NUMA_BALANCING is set or not. So, when an application calls set_mempolicy() with MPOL_F_NUMA_BALANCING set but both MPOL_F_STATIC_NODES and MPOL_F_RELATIVE_NODES cleared, mempolicy.w.cpuset_mems_allowed should be set to cpuset_current_mems_allowed nodemask. However, in current implementation, mpol_store_user_nodemask() wrongly returns true, causing mempolicy->w.user_nodemask to be incorrectly set to the user-specified nodemask. Later, when the cpuset of the application changes, mpol_rebind_nodemask() ends up rebinding based on the user-specified nodemask rather than the cpuset_mems_allowed nodemask as intended. I can reproduce with the following steps in qemu with 4 NUMA nodes: 1. echo '+cpuset' > /sys/fs/cgroup/cgroup.subtree_control 2. mkdir /sys/fs/cgroup/test 3. ./reproducer & 4. cat /proc/$pid/numa_maps, the task is bound to NUMA 1 5. echo $pid > /sys/fs/cgroup/test/cgroup.procs 6. cat /proc/$pid/numa_maps, the task is bound to NUMA 0 now. The reproducer code: int main() { struct bitmask *bmp; int ret; bmp = numa_parse_nodestring("1"); ret = set_mempolicy(MPOL_BIND | MPOL_F_NUMA_BALANCING, bmp->maskp, bmp->size + 1); if (ret < 0) { perror("Failed to call set_mempolicy"); exit(-1); } while (1); return 0; } If I call set_mempolicy() without MPOL_F_NUMA_BALANCING in the reproducer code. After step 5, the task is still bound to NUMA 1. To fix this, only set mempolicy->w.user_nodemask to the user-specified nodemask if MPOL_F_STATIC_NODES or MPOL_F_RELATIVE_NODES is present. Link: https://lkml.kernel.org/r/20260120011018.1256654-1-tujinjiang@huawei.com Link: https://lkml.kernel.org/r/20251223110523.1161421-1-tujinjiang@huawei.com Fixes: bda420b98505 ("numa balancing: migrate on fault among multiple bound nodes") Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com> Reviewed-by: Gregory Price <gourry@gourry.net> Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Mathew Brost <matthew.brost@intel.com> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26zsmalloc: introduce SG-list based object read APISergey Senozhatsky
Currently, zsmalloc performs address linearization on read (which sometimes requires memcpy() to a local buffer). Not all zsmalloc users need a linear address. For example, Crypto API supports SG-list, performing linearization under the hood, if needed. In addition, some compressors can have native SG-list support, completely avoiding the linearization step. Provide an SG-list based zsmalloc read API: - zs_obj_read_sg_begin() - zs_obj_read_sg_end() This API allows callers to obtain an SG representation of the object (one entry for objects that are contained in a single page and two entries for spanning objects), avoiding the need for a bounce buffer and memcpy. [senozhatsky@chromium.org: make zs_obj_read_sg_begin() return void, per Yosry] Link: https://lkml.kernel.org/r/20260117024900.792237-1-senozhatsky@chromium.org Link: https://lkml.kernel.org/r/20260113034645.2729998-1-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Tested-by: Yosry Ahmed <yosry.ahmed@linux.dev> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Brian Geffon <bgeffon@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm: kmsan: add test_uninit_pageAlexander Potapenko
Test that pages allocated with alloc_page() are uninitialized by default. Link: https://lkml.kernel.org/r/20260113091151.4035013-2-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm: kmsan: add tests for high-order page freeingAlexander Potapenko
Add regression tests to verify that KMSAN correctly poisons the full memory range when freeing pages. Specifically, verify that accessing the tail pages of a high-order non-compound allocation triggers a use-after-free report. This ensures that the fix "mm: kmsan: Fix poisoning of high-order non-compound pages" is working as expected. Also add a test for standard order-0 pages for completeness. Link: https://lore.kernel.org/all/20260104134348.3544298-1-ryan.roberts@arm.com/ Link: https://lkml.kernel.org/r/20260113091151.4035013-1-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26Docs/admin-guide/mm/damon/lru_sort: document intervals autotuningSeongJae Park
Document a newly added DAMON_LRU_SORT module parameter for using monitoring intervals auto-tuning feature of DAMON. Link: https://lkml.kernel.org/r/20260113152717.70459-12-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Acked-by: wang lian <lianux.mm@gmail.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/damon/lru_sort: add monitoring intervals auto-tuning parameterSeongJae Park
DAMON monitoring intervals tuning was crucial for every DAMON use case. Now there are a tuning guideline and an automated intervals tuning feature. DAMON_LRU_SORT is still using manual control of intervals. Add a module parameter for utilizing the auto-tuning feature with a suggested auto-tuning parameters. Link: https://lkml.kernel.org/r/20260113152717.70459-11-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Acked-by: wang lian <lianux.mm@gmail.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26Docs/admin-guide/mm/damon/lru_sort: document active_mem_bp parameterSeongJae Park
Document a newly added DAMON_LRU_SORT parameter for doing auto-tuning aiming an active to inactive memory size ratio. Link: https://lkml.kernel.org/r/20260113152717.70459-10-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Acked-by: wang lian <lianux.mm@gmail.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/damon/lru_sort: support active:inactive memory ratio based auto-tuningSeongJae Park
Doing DAMOS_LRU_[DE]PRIO with DAMOS_QUOTA_[IN]ACTIVE_MEM_BP based quota auto-tuning can be easy and intuitive, compared to the manual [de]prioritization target access pattern thresholds tuning. For example, users can ask DAMON to "find hot/cold pages and activate/deactivate those aiming 50:50 active:inactive memory size." But DAMON_LRU_SORT has no interface to do that. Add a module parameter for setting the target ratio. [sj@kernel.org: add inactive mem ratio quota goal to cold_scheme] Link: https://lkml.kernel.org/r/20260114055308.79884-1-sj@kernel.org Link: https://lkml.kernel.org/r/20260113152717.70459-9-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26Docs/admin-guide/mm/damon/lru_sort: document filter_young_pagesSeongJae Park
Document the new DAMON_LRU_SORT parameter, filter_young_pages. It can be used to use page level access re-check for the LRU sorting. Link: https://lkml.kernel.org/r/20260113152717.70459-8-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Acked-by: wang lian <lianux.mm@gmail.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/damon/lru_sort: support young page filtersSeongJae Park
DAMON monitors access patterns at the region level, and hence there could be some page level mismatches. A few hot pages could be located in cold regions, and vice versa. Young page filters can be useful for doing additional page level access checks before applying some DAMOS action. DAMON_LRU_SORT is not using young page filters, though. Add a parameter for using it. Link: https://lkml.kernel.org/r/20260113152717.70459-7-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/damon/lru_sort: consider age for quota prioritizationSeongJae Park
DAMON_LRU_SORT is doing under-quota access pattern based regions prioritization using only access frequency. Age of regions is another useful information for distinguishing hot and cold regions. Use it for prioritization, too. Link: https://lkml.kernel.org/r/20260113152717.70459-6-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/damon/paddr: activate DAMOS_LRU_PRIO targets instead of marking accessedSeongJae Park
DAMOS_LRU_DEPRIOD directly deactivates the pages, while DAMOS_LRU_PRIO calls folio_mark_accessed(), which does incremental activation. The incremental activation was assumed to be useful for making sure the pages of the hot memory region are really hot. After the introduction of DAMOS_LRU_PRIO, the young page filter has added. Users can use the young page filter to make sure the page is eligible to be activated. Meanwhile, the asymmetric behavior of DAMOS_LRU_[DE]PRIO can confuse users. Directly activate given pages for DAMOS_LRU_PRIO, to eliminate the unnecessary incremental activation steps, and be symmetric with DAMOS_LRU_DEPRIO for easier usages. Link: https://lkml.kernel.org/r/20260113152717.70459-5-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26Docs/mm/damon/design: document DAMOS_QUOTA_[IN]ACTIVE_MEM_BPSeongJae Park
Update design document for newly added DAMOS_QUOTA_[IN]ACTIVE_MEM_BP metrics. Note that API document is automatically updated by kernel-doc comment, and the usage document points to the design document which uses keywords same to that for sysfs inputs. Hence updating only design document is sufficient. Link: https://lkml.kernel.org/r/20260113152717.70459-4-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Acked-by: wang lian <lianux.mm@gmail.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/damon/sysfs-schemes: support DAMOS_QUOTA_[IN]ACTIVE_MEM_BPSeongJae Park
Add support of DAMOS_QUOTA_[IN]ACTIVE_MEM_BP on DAMON sysfs interface. Users can use [in]active_mem_bp keyword input to the target_metric sysfs file to use the new DAMOS quota auto-tune target metrics. Link: https://lkml.kernel.org/r/20260113152717.70459-3-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Acked-by: wang lian <lianux.mm@gmail.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/damon/core: introduce [in]active memory ratio damos quota goal metricSeongJae Park
Patch series "mm/damon: advance DAMOS-based LRU sorting". DAMOS_LRU_[DE]PRIO actions were added to DAMOS for more access-aware LRU lists sorting. For simple usage, a specialized kernel module, namely DAMON_LRU_SORT, has also been introduced. After the introduction of the module, DAMON got a few important new features, including the aim-based quota auto-tuning, age tracking, young page filter, and monitoring intervals auto-tuning. Meanwhile, DAMOS-based LRU sorting had no direct updates. Now we show some rooms to advance for DAMOS-based LRU sorting. Firstly, the aim-oriented quota auto-tuning can simplify the LRU sorting parameters tuning. But there is no good auto-tuning target metric for LRU sorting use case. Secondly, the behavior of DAMOS_LRU_[DE]PRIO are not very symmetric. DAMOS_LRU_DEPRIO directly moves the pages to inactive LRU list, while DAMOS_LRU_PRIO only marks the page as accessed, so that the page can not directly but only eventually moved to the active LRU list. Finally, DAMON_LRU_SORT users cannot utilize the modern features that can be useful for them, too. Improve the situation with the following changes. First, introduce a new DAMOS quota auto-tuning target metric for active:inactive memory size ratio. Since LRU sorting is a kind of balancing of active and inactive pages, the active:inactive memory size ratio can be intuitively set. Second, update DAMOS_LRU_[DE]PRIO behaviors to be more intuitive and symmetric, by letting them directly move the pages to [in]active LRU list. Third, update the DAMON_LRU_SORT module user interface to be able to fully utilize the modern features including the [in]active memory size ratio-based quota auto-tuning, young page filter, and monitoring intervals auto-tuning. With these changes, for example, users can now ask DAMON to "find hot/cold memory regions with auto-tuned monitoring intervals, do one more page level access check for found hot/cold memory, and move pages of those to active or inactive LRU lists accordingly, aiming X:Y active to inactive memory ratio." For example, if they know 30% of the memory is better to be protected from reclamation, 30:70 can be set as the target ratio. Test Results ------------ I ran DAMON_LRU_SORT with the features introduced by this series, on a real world server workload. For the active:inactive ratio goal, I set 50:50. I confirmed it achieves the target active:inactive ratio, without manual tuning of the monitoring intervals and the hot/coldness thresholds. The baseline system that was not running the DAMON_LRU_SORT was keeping active:inactive ratio of about 1:10. Note that the test didn't show a clear performance difference, though. I believe that was mainly because the workload was not very memory intensive. Also, whether the 50:50 target ratio was optimum is unclear. Nonetheless, the positive performance impact of the basic LRU sorting idea is already confirmed with the initial DAMON_LRU_SORT introduction patch series. The goal of this patch series is simplifying the parameters tuning of DAMOS-based LRU sorting, and the test confirmed the aimed goals are achieved. Patches Sequence ---------------- First three patches extend DAMOS quota auto-tuning to support [in]active memory ratio target metric type. Those (patches 1-3) introduce new metrics, implement DAMON sysfs support, and update the documentation, respectively. Following patch (patch 4) makes DAMOS_LRU_PRIO action to directly move target pages to active LRU list, instead of only marking them accessed. Following seven patches (patches 5-11) updates DAMON_LRU_SORT to support modern DAMON features. Patch 5 makes it uses not only access frequency but also age at under-quota regions prioritization. Patches 6-11 add the support for young page filtering, active:inactive memory ratio based quota auto-tuning, and monitoring intervals auto-tuning, with appropriate document updates. This patch (of 11): DAMOS_LRU_[DE]PRIO are DAMOS actions for making balance of active and inactive memory size. There is no appropriate DAMOS quota auto-tuning target metric for the use case. Add two new DAMOS quota goal metrics for the purpose, namely DAMOS_QUOTA_[IN]ACTIVE_MEM_BP. Those will represent the ratio of [in]active memory to total (inactive + active) memory. Hence, users will be able to ask DAMON to, for example, "find hot and cold memory, and move pages of those to active and inactive LRU lists, adjusting the hot/cold thresholds aiming 50:50 active:inactive memory ratio." Link: https://lkml.kernel.org/r/20260113152717.70459-1-sj@kernel.org Link: https://lkml.kernel.org/r/20260113152717.70459-2-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/kasan/kunit: extend vmalloc OOB tests to cover vrealloc()Andrey Ryabinin
Extend the vmalloc_oob() test to validate OOB detection after resizing vmalloc allocations with vrealloc(). The test now verifies that KASAN correctly poisons and unpoisons vmalloc memory when allocations are shrunk and expanded, ensuring OOB accesses are reliably detected after each resize. [ryabinin.a.a@gmail.com: adjust vrealloc() size] Link: https://lkml.kernel.org/r/20260116132822.22227-1-ryabinin.a.a@gmail.com Link: https://lkml.kernel.org/r/20260113191516.31015-2-ryabinin.a.a@gmail.com Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Maciej Żenczykowski <maze@google.com> Cc: Uladzislau Rezki <urezki@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26vmalloc: export vrealloc_node_align_noprofAlice Ryhl
This symbol is used from the Nova driver, so it needs to be exported to avoid a build failure when building Nova as a module. ERROR: modpost: "vrealloc_node_align_noprof" [drivers/gpu/nova-core/nova_core.ko] undefined! ERROR: modpost: "vrealloc_node_align_noprof" [samples/rust/rust_dma.ko] undefined! This error is only triggered if helpers are inlined into Rust. Otherwise, Nova will call the exported symbol rust_helper_vrealloc_node_align() instead. There is no Fixes: tag as that feature is still WIP. I used non-GPL EXPORT_SYMBOL to match the rest of the file, but let me know if I should use EXPORT_SYMBOL_GPL. Link: https://lkml.kernel.org/r/20260107-export-vrealloc_node_align_noprof-v1-1-a581bec13054@google.com Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Danilo Krummrich <dakr@kernel.org> Cc: Andreas Hindborg <a.hindborg@kernel.org> Cc: Björn Roy Baron <bjorn3_gh@protonmail.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Gary Guo <gary@garyguo.net> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Trevor Gross <tmgross@umich.edu> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm: hugetlb: allocate frozen pages for gigantic allocationKefeng Wang
alloc_gigantic_folio() allocates a folio with refcount increated and then freeze it, convert to allocate a frozen folio to remove the atomic operation about folio refcount, and saving atomic operation during __update_and_free_hugetlb_folio() too. Besides, rename hugetlb_cma_{alloc,free}_folio(), alloc_gigantic_folio() and alloc_buddy_hugetlb_folio() with frozen which make them more self-explanatory. Link: https://lkml.kernel.org/r/20260109093136.1491549-7-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Cc: Brendan Jackman <jackmanb@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm: cma: add cma_alloc_frozen{_compound}()Kefeng Wang
Introduce cma_alloc_frozen{_compound}() helper to alloc pages without incrementing their refcount, then convert hugetlb cma to use the cma_alloc_frozen_compound() and cma_release_frozen() and remove the unused cma_{alloc,free}_folio(), also move the cma_validate_zones() into mm/internal.h since no outside user. The set_pages_refcounted() is only called to set non-compound pages after above changes, so remove the processing about PageHead. Link: https://lkml.kernel.org/r/20260109093136.1491549-6-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm: page_alloc: add alloc_contig_frozen_{range,pages}()Kefeng Wang
In order to allocate given range of pages or allocate compound pages without incrementing their refcount, adding two new helper alloc_contig_frozen_{range,pages}() which may be beneficial to some users (eg hugetlb). The new alloc_contig_{range,pages} only take !__GFP_COMP gfp now, and the free_contig_range() is refactored to only free non-compound pages, the only caller to free compound pages in cma_free_folio() is changed accordingly, and the free_contig_frozen_range() is provided to match the alloc_contig_frozen_range(), which is used to free frozen pages. Link: https://lkml.kernel.org/r/20260109093136.1491549-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm: cma: kill cma_pages_valid()Kefeng Wang
Kill cma_pages_valid() which only used in cma_release(), also cleanup code duplication between cma pages valid checking and cma memrange finding. Link: https://lkml.kernel.org/r/20260109093136.1491549-4-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm: page_alloc: add __split_page()Kefeng Wang
Factor out the splitting of non-compound page from make_alloc_exact() and split_page() into a new helper function __split_page(). While at it, convert the VM_BUG_ON_PAGE() into a VM_WARN_ON_PAGE(). Link: https://lkml.kernel.org/r/20260109093136.1491549-3-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Muchun Song <muchun.song@linux.dev> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm: debug_vm_pgtable: add debug_vm_pgtable_free_huge_page()Kefeng Wang
Patch series "mm: hugetlb: allocate frozen gigantic folio", v6. Introduce alloc_contig_frozen_pages() and cma_alloc_frozen_compound() which avoid atomic operation about page refcount, and then convert to allocate frozen gigantic folio by the new helpers in hugetlb to cleanup the alloc_gigantic_folio(). This patch (of 6): Add a new helper to free huge page to be consistency to debug_vm_pgtable_alloc_huge_page(), and use HPAGE_PUD_ORDER instead of open-code. Also move the free_contig_range() under CONFIG_ALLOC_CONTIG since all caller are built with CONFIG_ALLOC_CONTIG. Link: https://lkml.kernel.org/r/20260109093136.1491549-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_nodeDeepanshu Kartikey
When CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during vmalloc cleanup triggers expensive stack unwinding that acquires RCU read locks. Processing a large purge_list without rescheduling can cause the task to hold CPU for extended periods (10+ seconds), leading to RCU stalls and potential OOM conditions. The issue manifests in purge_vmap_node() -> kasan_release_vmalloc_node() where iterating through hundreds or thousands of vmap_area entries and freeing their associated shadow pages causes: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l ... task:kworker/0:17 state:R running task stack:28840 pid:6229 ... kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299 purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299 Each call to kasan_release_vmalloc() can free many pages, and with page_owner tracking, each free triggers save_stack() which performs stack unwinding under RCU read lock. Without yielding, this creates an unbounded RCU critical section. Add periodic cond_resched() calls within the loop to allow: - RCU grace periods to complete - Other tasks to run - Scheduler to preempt when needed The fix uses need_resched() for immediate response under load, with a batch count of 32 as a guaranteed upper bound to prevent worst-case stalls even under light load. Link: https://lkml.kernel.org/r/20260112103612.627247-1-kartikey406@gmail.com Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com> Reported-by: syzbot+d8d4c31d40f868eaea30@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d8d4c31d40f868eaea30 Link: https://lore.kernel.org/all/20260112084723.622910-1-kartikey406@gmail.com/T/ [v1] Suggested-by: Uladzislau Rezki <urezki@gmail.com> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Hillf Danton <hdanton@sina.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/early_ioremap: clean up the use of WARN() for debuggingHou Wenlong
Using WARN() for debugging is strange when nothing is wrong, so replace WARN(early_ioremap_debug) with pr_warn() + dump_stack(). Link: https://lkml.kernel.org/r/d4470531ce0c03fd80f9a1be7e8d8ae1bc60fcd1.1768220636.git.houwenlong.hwl@antgroup.com Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> Suggested-by: Mike Rapoport <rppt@kernel.org> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Hou Wenlong <houwenlong.hwl@antgroup.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/early_ioremap: print the starting physical address in __early_ioremap()Hou Wenlong
The debug WARN() printing occurs after the while loop, so the 'phys_addr' reflects the last physical address rather than the actual starting physical address, which is not useful for debugging. To simplify, the WARN() statement could be moved up before the loop instead of introducing a new variable to record the original 'phys_addr' value. Additionally, swap the print order of 'slot_virt[slot]' and 'offset', as this will enhance output readability. Link: https://lkml.kernel.org/r/aa2d44c34f44c31b50285b7592ed4fd78d6f59ba.1767965415.git.houwenlong.hwl@antgroup.com Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/damon/paddr: initialize 'folio' variables to NULL for clarityAaron Yang
In damon_pa_mark_accessed_or_deactivate(), damon_pa_pageout(), damon_pa_migrate(), and damon_pa_stat(), the local variable 'folio' is declared but not initialized. Initialize 'folio' to NULL to improve code readability and maintainability. Link: https://patch.msgid.link/20260104013255.16962-1-yangqixiao@inspur.com Link: https://lkml.kernel.org/r/20260108013041.80601-1-sj@kernel.org Signed-off-by: Aaron Yang <yangqixiao@inspur.com> Reviewed-by: SeongJae Park <sj@kernel.org> Signed-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26zsmalloc: simplify read begin/end logicYosry Ahmed
zs_obj_read_begin() currently maps or copies the compressed object with the prefix handle for !ZsHugePage case. Make the logic clearer and more efficient by moving the offset of the object in the page after the prefix handle instead, only copying the actual object and avoiding the need to adjust the returned address to account for the prefix. Adjust the logic to detect spanning objects in zs_obj_read_end() accordingly, slightly simplifying it by avoiding the need to account for the handle in both the offset and the object size. Link: https://lkml.kernel.org/r/20260107052145.3586917-2-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Co-developed-by: Yosry Ahmed <yosry.ahmed@linux.dev> Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev> Cc: Brian Geffon <bgeffon@google.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26zsmalloc: use actual object size to detect spansSergey Senozhatsky
Using class->size to detect spanning objects is not entirely correct, because some size classes can hold a range of object sizes of up to class->size bytes in length, due to size-classes merge. Such classes use padding for cases when actually written objects are smaller than class->size. zs_obj_read_begin() can incorrectly hit the slow path and perform memcpy of such objects, basically copying padding bytes. Instead of class->size zs_obj_read_begin() should use the actual compressed object length (both zram and zswap know it) so that it can correctly handle situations when a written object is small enough to fit into the first physical page. Link: https://lkml.kernel.org/r/20260107052145.3586917-1-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev> [zsmalloc & zswap] Reviewed-by: Nhat Pham <nphamcs@gmail.com> Cc: Brian Geffon <bgeffon@google.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26memcg: rename mem_cgroup_ino() to mem_cgroup_id()Shakeel Butt
Rename mem_cgroup_ino() to mem_cgroup_id() and mem_cgroup_get_from_ino() to mem_cgroup_get_from_id(). These functions now use cgroup IDs (from cgroup_id()) rather than inode numbers, so the names should reflect that. [shakeel.butt@linux.dev: replace ino with id, per SeongJae] Link: https://lkml.kernel.org/r/flkqanhyettp5uq22bjwg37rtmnpeg3mghznsylxcxxgaafpl4@nov2x7tagma7 [akpm@linux-foundation.org: build fix] Link: https://lkml.kernel.org/r/20251225232116.294540-9-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Dave Chinner <david@fromorbit.com> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26memcg: remove unused mem_cgroup_id() and mem_cgroup_from_id()Shakeel Butt
Now that all callers have been converted to use either: - The private ID APIs (mem_cgroup_private_id/mem_cgroup_from_private_id) for internal kernel objects that outlive their cgroup - The public cgroup ID APIs (mem_cgroup_ino/mem_cgroup_get_from_ino) for external interfaces Remove the unused wrapper functions mem_cgroup_id() and mem_cgroup_from_id() along with their !CONFIG_MEMCG stubs. Link: https://lkml.kernel.org/r/20251225232116.294540-8-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Dave Chinner <david@fromorbit.com> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/vmscan: use cgroup ID instead of private memcg ID in lru_gen interfaceShakeel Butt
The LRU gen debugfs interface was using the internal private memcg ID which is meant for tracking kernel objects that outlive their cgroup. Switch to using the public cgroup ID instead. Link: https://lkml.kernel.org/r/20251225232116.294540-7-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Dave Chinner <david@fromorbit.com> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/damon: use cgroup ID instead of private memcg IDShakeel Butt
DAMON was using the internal private memcg ID which is meant for tracking kernel objects that outlive their cgroup. Switch to using the public cgroup ID instead. Link: https://lkml.kernel.org/r/20251225232116.294540-6-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: SeongJae Park <sj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Dave Chinner <david@fromorbit.com> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26memcg: use cgroup_id() instead of cgroup_ino() for memcg IDShakeel Butt
Switch mem_cgroup_ino() from using cgroup_ino() to cgroup_id(). The cgroup_ino() returns the kernfs inode number while cgroup_id() returns the kernfs node ID. For 64-bit systems, they are the same. Also cgroup_get_from_id() expects 64-bit node ID which is called by mem_cgroup_get_from_ino(). Change the type from unsigned long to u64 to match cgroup_id()'s return type, and update the format specifiers accordingly. Note that the names mem_cgroup_ino() and mem_cgroup_get_from_ino() are now misnomers since they deal with cgroup IDs rather than inode numbers. A follow-up patch will rename them. Link: https://lkml.kernel.org/r/20251225232116.294540-5-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Dave Chinner <david@fromorbit.com> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26memcg: mem_cgroup_get_from_ino() returns NULL on errorShakeel Butt
Change mem_cgroup_get_from_ino() to return NULL on error instead of ERR_PTR values. This simplifies the API: NULL indicates failure, and a valid pointer indicates success with a CSS reference held that the caller must release via mem_cgroup_put(). Link: https://lkml.kernel.org/r/20251225232116.294540-4-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Dave Chinner <david@fromorbit.com> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26memcg: expose mem_cgroup_ino() and mem_cgroup_get_from_ino() unconditionallyShakeel Butt
Remove the CONFIG_SHRINKER_DEBUG guards around mem_cgroup_ino() and mem_cgroup_get_from_ino(). These APIs provide a way to get a memcg's cgroup inode number and to look up a memcg from an inode number respectively. Making these functions unconditionally available allows other in-kernel users to leverage them without requiring CONFIG_SHRINKER_DEBUG to be enabled. No functional change for existing users. Link: https://lkml.kernel.org/r/20251225232116.294540-3-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Dave Chinner <david@fromorbit.com> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26memcg: introduce private id API for in-kernel usersShakeel Butt
Patch series "memcg: separate private and public ID namespaces". The memory cgroup subsystem maintains a private ID infrastructure that is decoupled from the cgroup IDs. This private ID system exists because some kernel objects (like swap entries and shadow entries in the workingset code) can outlive the cgroup they were associated with. The motivation is best described in commit 73f576c04b941 ("mm: memcontrol: fix cgroup creation failure after many small jobs"). Unfortunately, some in-kernel users (DAMON, LRU gen debugfs interface, shrinker debugfs) started exposing these private IDs to userspace. This is problematic because: 1. The private IDs are internal implementation details that could change 2. Userspace already has access to cgroup IDs through the cgroup filesystem 3. Using different ID namespaces in different interfaces is confusing This series cleans up the memcg ID infrastructure by: 1. Explicitly marking the private ID APIs with "private" in their names to make it clear they are for internal use only (swap/workingset) 2. Making the public cgroup ID APIs (mem_cgroup_id/mem_cgroup_get_from_id) unconditionally available 3. Converting DAMON, LRU gen, and shrinker debugfs interfaces to use the public cgroup IDs instead of the private IDs 4. Removing the now-unused wrapper functions and renaming the public APIs for clarity After this series: - mem_cgroup_private_id() / mem_cgroup_from_private_id() are used for internal kernel objects that outlive their cgroup (swap, workingset) - mem_cgroup_id() / mem_cgroup_get_from_id() return the public cgroup ID (from cgroup_id()) for use in userspace-facing interfaces This patch (of 8): The memory cgroup maintains a private ID infrastructure decoupled from the cgroup IDs for swapout records and shadow entries. The main motivation of this private ID infra is best described in the commit 73f576c04b941 ("mm: memcontrol: fix cgroup creation failure after many small jobs"). Unfortunately some users have started exposing these private IDs to the userspace where they should have used the cgroup IDs which are already exposed to the userspace. Let's rename the memcg ID APIs to explicitly mark them private. No functional change is intended. Link: https://lkml.kernel.org/r/20251225232116.294540-1-shakeel.butt@linux.dev Link: https://lkml.kernel.org/r/20251225232116.294540-2-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Dave Chinner <david@fromorbit.com> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/page_alloc: simplify __alloc_pages_slowpath() flowVlastimil Babka
The actions done before entering the main retry loop include waking up kswapds and an allocation attempt with the precise alloc_flags. Then in the loop we keep waking up kswapds, and we retry the allocation with flags potentially further adjusted by being allowed to use reserves (due to e.g. becoming an OOM killer victim). We can adjust the retry loop to keep only one instance of waking up kswapds and allocation attempt. Introduce the can_retry_reserves variable for retrying once when we become eligible for reserves. It is still useful not to evaluate reserve_flags immediately for the first allocation attempt, because it's better to first try succeed in a non-preferred zone above the min watermark before allocating immediately from the preferred zone below min watermark. Additionally move the cpuset update checks introduced by e05741fb10c3 ("mm/page_alloc.c: avoid infinite retries caused by cpuset race") further down the retry loop. It's enough to do the checks only before reaching any potentially infinite 'goto retry;' loop. There should be no meaningful functional changes. The change of exact moments the retry for reserves and cpuset updates are checked should not result in different outomes modulo races with concurrent allocator activity. Link: https://lkml.kernel.org/r/20260106-thp-thisnode-tweak-v3-3-f5d67c21a193@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: David Hildenbrand (Red Hat) <david@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/page_alloc: refactor the initial compaction handlingVlastimil Babka
The initial direct compaction done in some cases in __alloc_pages_slowpath() stands out from the main retry loop of reclaim + compaction. We can simplify this by instead skipping the initial reclaim attempt via a new local variable compact_first, and handle the compact_prority as necessary to match the original behavior. No functional change intended. Link: https://lkml.kernel.org/r/20260106-thp-thisnode-tweak-v3-2-f5d67c21a193@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: David Hildenbrand (Red Hat) <david@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/page_alloc: ignore the exact initial compaction resultVlastimil Babka
Patch series "tweaks for __alloc_pages_slowpath()", v3. This patch (of 3): For allocations that are of costly order and __GFP_NORETRY (and can perform compaction) we attempt direct compaction first. If that fails, we continue with a single round of direct reclaim+compaction (as for other __GFP_NORETRY allocations, except the compaction is of lower priority), with two exceptions that fail immediately: - __GFP_THISNODE is specified, to prevent zone_reclaim_mode-like behavior for e.g. THP page faults - compaction failed because it was deferred (i.e. has been failing recently so further attempts are not done for a while) or skipped, which means there are insufficient free base pages to defragment to begin with Upon closer inspection, the second condition has a somewhat flawed reasoning. If there are not enough base pages and reclaim could create them, we instead fail. When there are enough base pages and compaction has already ran and failed, we proceed and hope that reclaim and the subsequent compaction attempt will succeed. But it's unclear why they should and whether it will be as inexpensive as intended. It might make therefore more sense to just fail unconditionally after the initial compaction attempt. However that would change the semantics of __GFP_NORETRY to attempt reclaim at least once. Alternatively we can remove the compaction result checks and proceed with the single reclaim and (lower priority) compaction attempt, leaving only the __GFP_THISNODE exception for failing immediately. Link: https://lkml.kernel.org/r/20260106-thp-thisnode-tweak-v3-0-f5d67c21a193@suse.cz Link: https://lkml.kernel.org/r/20260106-thp-thisnode-tweak-v3-1-f5d67c21a193@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: David Hildenbrand (Red Hat) <david@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/rmap: separate out fork-only logic on anon_vma_clone()Lorenzo Stoakes
Specify which operation is being performed to anon_vma_clone(), which allows us to do checks specific to each operation type, as well as to separate out and make clear that the anon_vma reuse logic is absolutely specific to fork only. This opens the door to further refactorings and refinements later as we have more information to work with. Link: https://lkml.kernel.org/r/cf7da7a2d973cdc72a1b80dd9a73260519e8fa9f.1768746221.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chris Li <chriscli@google.com> Cc: David Hildenbrand <david@kernel.org> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/rmap: allocate anon_vma_chain objects unlocked when possibleLorenzo Stoakes
There is no reason to allocate the anon_vma_chain under the anon_vma write lock when cloning - we can in fact assign these to the destination VMA safely as we hold the exclusive mmap lock and therefore preclude anybody else accessing these fields. We only need take the anon_vma write lock when we link rbtree edges from the anon_vma to the newly established AVCs. This also allows us to eliminate the weird GFP_NOWAIT, GFP_KERNEL dance introduced in commit dd34739c03f2 ("mm: avoid anon_vma_chain allocation under anon_vma lock"), further simplifying this logic. This should reduce lock anon_vma contention, and clarifies exactly where the anon_vma lock is required. We cannot adjust __anon_vma_prepare() in the same way as this is only protected by VMA read lock, so we have to perform the allocation here under the anon_vma write lock and page_table_lock (to protect against racing threads), and we wish to retain the lock ordering. With this change we can simplify cleanup_partial_anon_vmas() even further - since we allocate AVC's without any lock taken and do not insert anything into the interval tree until after the allocations are tried, we can remove all logic pertaining to this and just free up AVC's only. Link: https://lkml.kernel.org/r/624bf1ac0bde4871fcfca2c8c8e294b6d8f7ae7b.1768746221.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chris Li <chriscli@google.com> Cc: David Hildenbrand <david@kernel.org> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/mmap_lock: add vma_is_attached() helperLorenzo Stoakes
This makes it easy to explicitly check for VMA detachment, which is useful for things like asserts. Note that we intentionally do not allow this function to be available should CONFIG_PER_VMA_LOCK be set - this is because vma_assert_attached() and vma_assert_detached() are no-ops if !CONFIG_PER_VMA_LOCK, so there is no correct state for vma_is_attached() to be in if this configuration option is not specified. Therefore users elsewhere must invoke this function only after checking for CONFIG_PER_VMA_LOCK. We rework the assert functions to utilise this. Link: https://lkml.kernel.org/r/0172d3bf527ca54ba27d8bce8f8476095b241ac7.1768746221.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chris Li <chriscli@google.com> Cc: David Hildenbrand <david@kernel.org> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/rmap: make anon_vma functions internalLorenzo Stoakes
The bulk of the anon_vma operations are only used by mm, so formalise this by putting the function prototypes and inlines in mm/internal.h. This allows us to make changes without having to worry about the rest of the kernel. Link: https://lkml.kernel.org/r/79ec933c3a9c8bf1f64dab253bbfdae8a01cb921.1768746221.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chris Li <chriscli@google.com> Cc: David Hildenbrand <david@kernel.org> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26mm/rmap: remove anon_vma_merge() functionLorenzo Stoakes
This function is confusing, we already have the concept of anon_vma merge to adjacent VMA's anon_vma's to increase probability of anon_vma compatibility and therefore VMA merge (see is_mergeable_anon_vma() etc.), as well as anon_vma reuse, along side the usual VMA merge logic. We can remove the anon_vma check as it is redundant - a merge would not have been permitted with removal if the anon_vma's were not the same (and in the case of an unfaulted/faulted merge, we would have already set the unfaulted VMA's anon_vma to vp->remove->anon_vma in dup_anon_vma()). Avoid overloading this term when we're very simply unlinking anon_vma state from a removed VMA upon merge. Link: https://lkml.kernel.org/r/56bbe45e309f7af197b1c4f94a9a0c8931ff2d29.1768746221.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chris Li <chriscli@google.com> Cc: David Hildenbrand <david@kernel.org> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Rik van Riel <riel@surriel.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>