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2026-06-21selftests/mm: remove READ_ONLY_THP_FOR_FS in khugepagedZi Yan
Change the requirement to a file system with large folio support and the supported order needs to include PMD_ORDER. Also add tests of opening a file with read write permission and populating folios with writes. Reuse the XFS image from split_huge_page_test. Link: https://lore.kernel.org/20260517135416.1434539-12-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand (Arm) <david@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21fs/btrfs: remove a comment referring to READ_ONLY_THP_FOR_FSZi Yan
READ_ONLY_THP_FOR_FS is no longer present, remove related comment. Link: https://lore.kernel.org/20260517135416.1434539-11-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: David Sterba <dsterba@suse.com> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam@infradead.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/truncate: use folio_split() in truncate_inode_partial_folio()Zi Yan
After READ_ONLY_THP_FOR_FS is removed, FS either supports large folio or not. folio_split() can be used on a FS with large folio support without worrying about getting a THP on a FS without large folio support. When READ_ONLY_THP_FOR_FS was present, a PMD large pagecache folio can appear in a FS without large folio support after khugepaged or madvise(MADV_COLLAPSE) creates it. During truncate_inode_partial_folio(), such a PMD large pagecache folio is split and if the FS does not support large folio, it needs to be split to order-0 ones and could not be split non uniformly to ones with various orders. try_folio_split_to_order() was added to handle this situation by checking folio_check_splittable(..., SPLIT_TYPE_NON_UNIFORM) to detect if the large folio is created due to READ_ONLY_THP_FOR_FS and the FS does not support large folio. Now READ_ONLY_THP_FOR_FS is removed, all large pagecache folios are created with FSes supporting large folio, this function is no longer needed and all large pagecache folios can be split non uniformly. Link: https://lore.kernel.org/20260517135416.1434539-10-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/huge_memory: remove folio split check for READ_ONLY_THP_FOR_FSZi Yan
Without READ_ONLY_THP_FOR_FS, large file-backed folios cannot be created by a FS without large folio support. The check is no longer needed. Link: https://lore.kernel.org/20260517135416.1434539-9-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam Howlett <liam@infradead.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21fs: remove nr_thps from struct address_spaceZi Yan
filemap_nr_thps*() are removed, the related field, address_space->nr_thps, is no longer needed. Remove it. This shrinks struct address_space by 8 bytes on 64-bit systems which may increase the number of inodes we can cache. Link: https://lore.kernel.org/20260517135416.1434539-8-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Nico Pache <npache@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam Howlett <liam@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm: fs: remove filemap_nr_thps*() functions and their usersZi Yan
They are used by READ_ONLY_THP_FOR_FS to handle writes to FSes without large folio support, so that read-only THPs created in these FSes are not seen by the FSes when the underlying fd becomes writable. Now read-only PMD THPs only appear in a FS with large folio support and the supported orders include PMD_ORDER. READ_ONLY_THP_FOR_FS was using mapping->nr_thps, inode->i_writecount, and smp_mb() to prevent writes to a read-only THP and collapsing writable folios into a THP. In collapse_file(), mapping->nr_thps is increased, then smp_mb(), and if inode->i_writecount > 0, collapse is stopped, while do_dentry_open() first increases inode->i_writecount, then a full memory fence, and if mapping->nr_thps > 0, all read-only THPs are truncated. Now this mechanism can be removed along with READ_ONLY_THP_FOR_FS code, since a dirty folio check has been added after try_to_unmap() in collapse_file() to prevent dirty folios from being collapsed as clean. Link: https://lore.kernel.org/20260517135416.1434539-7-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm: remove READ_ONLY_THP_FOR_FS Kconfig optionZi Yan
After removing READ_ONLY_THP_FOR_FS check in file_thp_enabled(), khugepaged and MADV_COLLAPSE can run on FSes with PMD THP pagecache support even without READ_ONLY_THP_FOR_FS enabled. Remove the Kconfig first so that no one can use READ_ONLY_THP_FOR_FS as upcoming commits remove mapping->nr_thps, which its safe guard mechanism relies on. Link: https://lore.kernel.org/20260517135416.1434539-6-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Nico Pache <npache@redhat.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam Howlett <liam@infradead.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: remove READ_ONLY_THP_FOR_FS check in hugepage_enabled()Zi Yan
Remove the READ_ONLY_THP_FOR_FS gate and khugepaged for file-backed pmd-sized hugepages are enabled by the global transparent hugepage control. khugepaged can still be enabled by per-size control for anon and shmem when the global control is off. Add shmem_hpage_pmd_enabled() stub for !CONFIG_SHMEM to remove IS_ENABLED(SHMEM) in hugepage_enabled(). Clean up hugepage_enabled() by moving anon code to anon_hpage_enabled(). Link: https://lore.kernel.org/20260517135416.1434539-5-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Nico Pache <npache@redhat.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/huge_memory: remove READ_ONLY_THP_FOR_FS from file_thp_enabled()Zi Yan
Replace it with a check on the max folio order of the file's address space mapping, making sure PMD folio is supported. Keep the inode open-for-write check, since even if collapse_file() now makes sure all to-be-collapsed folios are clean and the created PMD file THP can be handled by FSes properly, the filemap_flush() could perform undesirable write back. Link: https://lore.kernel.org/20260517135416.1434539-4-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Nico Pache <npache@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: add folio dirty check after try_to_unmap()Zi Yan
This check ensures the correctness of read-only PMD folio collapse after it is enabled for all FSes supporting PMD pagecache folios and replaces READ_ONLY_THP_FOR_FS. READ_ONLY_THP_FOR_FS only supports read-only fd and uses mapping->nr_thps and inode->i_writecount to prevent any write to read-only to-be-collapsed folios. In upcoming commits, READ_ONLY_THP_FOR_FS will be removed and the aforementioned mechanism will go away too. To ensure khugepaged functions as expected after the changes, skip if any folio is dirty after try_to_unmap(), since a dirty folio at that point means this read-only folio can get writes between try_to_unmap() and try_to_unmap_flush() via cached TLB entries and khugepaged does not support writable pagecache folio collapse yet. Link: https://lore.kernel.org/20260517135416.1434539-3-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Nico Pache <npache@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: remove READ_ONLY_THP_FOR_FS checkZi Yan
Patch series "Remove CONFIG_READ_ONLY_THP_FOR_FS and enable file THP for writable files", v6. This patch (of 14): collapse_file() requires FSes supporting large folio with at least PMD_ORDER, so replace the READ_ONLY_THP_FOR_FS check with that. MADV_COLLAPSE ignores shmem huge config, so exclude the check for shmem. While at it, replace VM_BUG_ON with VM_WARN_ON_ONCE. Add a helper function mapping_pmd_folio_support() for FSes supporting large folio with at least PMD_ORDER. Link: https://lore.kernel.org/20260517135416.1434539-1-ziy@nvidia.com Link: https://lore.kernel.org/20260517135416.1434539-2-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Nico Pache <npache@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Barry Song <baohua@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: fix PMD collapse swap PTE accountingLance Yang
mthp_collapse() uses mthp_present_ptes to decide whether a range has enough occupied PTEs to try collapse. Swap PTEs accepted by collapse_scan_pmd() are counted in unmapped, but are not represented in mthp_present_ptes. When lower orders are enabled, collapse_scan_pmd() relaxes max_ptes_none so the scan can cover the whole PMD and build the bitmap. mthp_collapse() then checks the PMD-order candidate using the bitmap. With max_ptes_none set to 0, a range with 511 present PTEs and one swap PTE no longer reaches collapse_huge_page(), even though PMD collapse can handle swap PTEs up to max_ptes_swap. Account unmapped PTEs only for PMD order. PMD collapse supports swap PTEs through max_ptes_swap, while lower-order mTHP collapse does not currently support non-present PTEs. Keep non-present PTEs out of the lower-order eligibility check. Link: https://lore.kernel.org/20260609120443.71864-1-lance.yang@linux.dev Fixes: 90ed32d00054 ("mm/khugepaged: introduce mTHP collapse support") Signed-off-by: Lance Yang <lance.yang@linux.dev> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: Nico Pache <npache@redhat.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: Barry Song <baohua@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21Documentation: mm: update the admin guide for mTHP collapseNico Pache
Now that we can collapse to mTHPs lets update the admin guide to reflect these changes and provide proper guidance on how to utilize it. Link: https://lore.kernel.org/20260605161422.213817-15-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: run khugepaged for all ordersBaolin Wang
If any order (m)THP is enabled we should allow running khugepaged to attempt scanning and collapsing mTHPs. In order for khugepaged to operate when only mTHP sizes are specified in sysfs, we must modify the predicate function that determines whether it ought to run to do so. This function is currently called hugepage_pmd_enabled(), this patch renames it to hugepage_enabled() and updates the logic to check to determine whether any valid orders may exist which would justify khugepaged running. We must also update collapse_possible_orders() to check all orders if the vma is anonymous and the collapse is khugepaged. After this patch khugepaged mTHP collapse is fully enabled. Link: https://lore.kernel.org/20260605161422.213817-14-npache@redhat.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Acked-by: Usama Arif <usama.arif@linux.dev> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: avoid unnecessary mTHP collapse attemptsNico Pache
There are cases where, if an attempted collapse fails, all subsequent orders are guaranteed to also fail. Avoid these collapse attempts by bailing out early. Link: https://lore.kernel.org/20260605161422.213817-13-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: Usama Arif <usama.arif@linux.dev> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: introduce mTHP collapse supportNico Pache
Enable khugepaged to collapse to mTHP orders. This patch implements the main scanning logic using a bitmap to track occupied pages and the algorithm to find optimal collapse sizes. Previous to this patch, PMD collapse had 3 main phases, a light weight scanning phase (mmap_read_lock) that determines a potential PMD collapse, an alloc phase (mmap unlocked), then finally heavier collapse phase (mmap_write_lock). To enabled mTHP collapse we make the following changes: During PMD scan phase, track occupied pages in a bitmap. When mTHP orders are enabled, we remove the restriction of max_ptes_none during the scan phase to avoid missing potential mTHP collapse candidates. Once we have scanned the full PMD range and updated the bitmap to track occupied pages, we use the bitmap to find the optimal mTHP size. Implement mthp_collapse() to walk forward through the bitmap and determine the best eligible order for each naturally-aligned region. The algorithm starts at the beginning of the PMD range and, for each offset, tries the highest order that fits the alignment. If the number of occupied PTEs in that region satisfies the max_ptes_none threshold for that order, a collapse is attempted. On failure, the order is decremented and the same offset is retried at the next smaller size. Once the smallest enabled order is exhausted (or a collapse succeeds), the offset advances past the region just processed, and the next attempt starts at the highest order permitted by the new offset's natural alignment. The algorithm works as follows: 1) set offset=0 and order=HPAGE_PMD_ORDER 2) if the order is not enabled, go to step (5) 3) count occupied PTEs in the (offset, order) range using bitmap_weight_from() 4) if the count satisfies the max_ptes_none threshold, attempt collapse; on success, advance to step (6) 5) if a smaller enabled order exists, decrement order and retry from step (2) at the same offset 6) advance offset past the current region and compute the next order from the new offset's natural alignment via __ffs(offset), capped at HPAGE_PMD_ORDER 7) repeat from step (2) until the full PMD range is covered mTHP collapses reject regions containing swapped out or shared pages. This is because adding new entries can lead to new none pages, and these may lead to constant promotion into a higher order mTHP. A similar issue can occur with "max_ptes_none > HPAGE_PMD_NR/2" due to a collapse introducing at least 2x the number of pages, and on a future scan will satisfy the promotion condition once again. This issue is prevented via the collapse_max_ptes_none() function which imposes the max_ptes_none restrictions above. We currently only support mTHP collapse for max_ptes_none values of 0 and HPAGE_PMD_NR - 1. resulting in the following behavior: - max_ptes_none=0: Never introduce new empty pages during collapse - max_ptes_none=HPAGE_PMD_NR-1: Always try collapse to the highest available mTHP order Any other max_ptes_none value will emit a warning and default mTHP collapse to max_ptes_none=0. There should be no behavior change for PMD collapse. Once we determine what mTHP sizes fits best in that PMD range a collapse is attempted. A minimum collapse order of 2 is used as this is the lowest order supported by anon memory as defined by THP_ORDERS_ALL_ANON. Currently madv_collapse is not supported and will only attempt PMD collapse. We can also remove the check for is_khugepaged inside the PMD scan as the collapse_max_ptes_none() function handles this logic now. Link: https://lore.kernel.org/20260605161422.213817-12-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: introduce collapse_possible_orders helper functionsNico Pache
Add collapse_possible_orders() to generalize THP order eligibility. The function determines which THP orders are permitted based on collapse context (khugepaged vs madv_collapse). We also add collapse_possible() as a thin wrapper around collapse_possible_orders() that returns a bool rather than the whole bitmap. This consolidates collapse configuration logic and provides a clean interface for future mTHP collapse support where the orders may be different. Link: https://lore.kernel.org/20260605161422.213817-11-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: improve tracepoints for mTHP ordersNico Pache
Add the order to the mm_collapse_huge_page<_swapin,_isolate> tracepoints to give better insight into what order is being operated at for. Link: https://lore.kernel.org/20260605161422.213817-10-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: add per-order mTHP collapse failure statisticsNico Pache
Add three new mTHP statistics to track collapse failures for different orders when encountering swap PTEs, excessive none PTEs, and shared PTEs: - collapse_exceed_swap_pte: Increment when mTHP collapse fails due to encountering a swap PTE. - collapse_exceed_none_pte: Counts when mTHP collapse fails due to exceeding the none PTE threshold for the given order - collapse_exceed_shared_pte: Counts when mTHP collapse fails due to encountering a shared PTE. These statistics complement the existing THP_SCAN_EXCEED_* events by providing per-order granularity for mTHP collapse attempts. The stats are exposed via sysfs under `/sys/kernel/mm/transparent_hugepage/hugepages-*/stats/` for each supported hugepage size. As we currently do not support collapsing mTHPs that contain a swap or shared entry, those statistics keep track of how often we are encountering failed mTHP collapses due to these restrictions. We will add support for mTHP collapse for anonymous pages next; lets also track when this happens at the PMD level within the per-mTHP stats. Link: https://lore.kernel.org/20260605161422.213817-9-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: skip collapsing mTHP to smaller ordersNico Pache
khugepaged may try to collapse a mTHP to a folio of equal or smaller size, possibly resulting in a partially mapped source folio, which is undesired. Skip these cases until we have a way to check if its ok to collapse to a smaller mTHP size (like in the case of a partially mapped folio). This check is not done during the scan phase as the current collapse order is unknown at that time. This patch is inspired by Dev Jain's work on khugepaged mTHP support [1]. Link: https://lore.kernel.org/20260605161422.213817-8-npache@redhat.com Link: https://lore.kernel.org/lkml/20241216165105.56185-11-dev.jain@arm.com/ [1] Co-developed-by: Dev Jain <dev.jain@arm.com> Signed-off-by: Dev Jain <dev.jain@arm.com> Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand (arm) <david@kernel.org> Acked-by: Usama Arif <usama.arif@linux.dev> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: generalize collapse_huge_page for mTHP collapseNico Pache
Pass an order to collapse_huge_page to support collapsing anon memory to arbitrary orders within a PMD. order indicates what mTHP size we are attempting to collapse to. For non-PMD collapse we must leave the anon VMA write locked until after we collapse the mTHP-- in the PMD case all the pages are isolated, but in the mTHP case this is not true, and we must keep the lock to prevent access/changes to the page tables. This can happen if the rmap walkers hit a pmd_none while the PMD entry is currently unavailable due to being temporarily removed during the collapse phase. To properly establish the page table hierarchy without violating any expectations from certain architectures (e.g. MIPS), we must make sure to have the PMD reinstalled before the PTEs, and hold both PTE/PMD locks before calling update_mmu_cache_range() (if they are distinct locks). Link: https://lore.kernel.org/20260605161422.213817-7-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: require collapse_huge_page to enter/exit with the lock droppedNico Pache
Currently the collapse_huge_page function requires the mmap_read_lock to enter with it held, and exit with it dropped. This function moves the unlock into its parent caller, and changes this semantic to requiring it to enter/exit with it always unlocked. In future patches, we need this expectation, as for in mTHP collapse, we may have already dropped the lock, and do not want to conditionally check for this by passing through the lock_dropped variable. No functional change is expected as one of the first things the collapse_huge_page function does is drop this lock before allocating the hugepage. Link: https://lore.kernel.org/20260605161422.213817-6-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: generalize __collapse_huge_page_* for mTHP supportNico Pache
generalize the order of the __collapse_huge_page_* and collapse_max_* functions to support future mTHP collapse. The current mechanism for determining collapse with the khugepaged_max_ptes_none value is not designed with mTHP in mind. This raises a key design issue: if we support user defined max_pte_none values (even those scaled by order), a collapse of a lower order can introduces an feedback loop, or "creep", when max_ptes_none is set to a value greater than HPAGE_PMD_NR / 2. [1] With this configuration, a successful collapse to order N will populate enough pages to satisfy the collapse condition on order N+1 on the next scan. This leads to unnecessary work and memory churn. To fix this issue introduce a helper function that will limit mTHP collapse support to two max_ptes_none values, 0 and HPAGE_PMD_NR - 1. This effectively supports two modes: [2] - max_ptes_none=0: never collapses if it encounters an empty PTE or a PTE that maps the shared zeropage. Consequently, no memory bloat. - max_ptes_none=511 (on 4k pagesz): Always collapse to the highest available mTHP order. This removes the possibility of "creep", and a warning will be emitted if any non-supported max_ptes_none value is configured with mTHP enabled. Any intermediate value will default mTHP collapse to max_ptes_none=0. mTHP collapse will not honor the khugepaged_max_ptes_shared or khugepaged_max_ptes_swap parameters, and will fail if it encounters a shared or swapped entry. No functional changes in this patch; however it defines future behavior for mTHP collapse. Link: https://lore.kernel.org/20260605161422.213817-5-npache@redhat.com Link: https://lore.kernel.org/all/e46ab3ab-a3d7-4fb7-9970-d0704bd5d05a@arm.com [1] Link: https://lore.kernel.org/all/37375ace-5601-4d6c-9dac-d1c8268698e9@redhat.com [2] Co-developed-by: Dev Jain <dev.jain@arm.com> Signed-off-by: Dev Jain <dev.jain@arm.com> Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Acked-by: David Hildenbrand (arm) <david@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Usama Arif <usama.arif@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: rework max_ptes_* handling with helper functionsNico Pache
The following cleanup reworks all the max_ptes_* handling into helper functions. This increases the code readability and will later be used to implement the mTHP handling of these variables. With these changes we abstract all the madvise_collapse() special casing (do not respect the sysctls) away from the functions that utilize them. And will be used later in this series to cleanly restrict the mTHP collapse behavior. No functional change is intended; however, we are now only reading the sysfs variables once per scan, whereas before these variables were being read on each loop iteration. Link: https://lore.kernel.org/20260605161422.213817-4-npache@redhat.com Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Reviewed-by: Lance Yang <lance.yang@linux.dev> Suggested-by: David Hildenbrand <david@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: Usama Arif <usama.arif@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: generalize alloc_charge_folio()Dev Jain
Pass order to alloc_charge_folio() and update mTHP statistics. Link: https://lore.kernel.org/20260605161422.213817-3-npache@redhat.com Signed-off-by: Dev Jain <dev.jain@arm.com> Co-developed-by: Nico Pache <npache@redhat.com> Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Usama Arif <usama.arif@linux.dev> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/khugepaged: generalize hugepage_vma_revalidate for mTHP supportNico Pache
Patch series "khugepaged: add mTHP collapse support", v19. The following series provides khugepaged with the capability to collapse anonymous memory regions to mTHPs. To achieve this we generalize the khugepaged functions to no longer depend on PMD_ORDER. Then during the PMD scan, we use a bitmap to track individual pages that are occupied (!none/zero). After the PMD scan is done, we use the bitmap to find the optimal mTHP sizes for the PMD range. The restriction on max_ptes_none is removed during the scan, to make sure we account for the whole PMD range in the bitmap. When no mTHP size is enabled, the legacy behavior of khugepaged is maintained. We currently only support max_ptes_none values of 0 or HPAGE_PMD_NR - 1 (ie 511). If any other value is specified, the kernel will emit a warning and mTHP collapse will default to max_ptes_none=0. If a mTHP collapse is attempted, but contains swapped out, or shared pages, we don't perform the collapse. It is now also possible to collapse to mTHPs without requiring the PMD THP size to be enabled. These limitations are to prevent collapse "creep" behavior. This prevents constantly promoting mTHPs to the next available size, which would occur because a collapse introduces more non-zero pages that would satisfy the promotion condition on subsequent scans. Patch 1-2: Generalize hugepage_vma_revalidate and alloc_charge_folio for arbitrary orders. Patch 3: Rework max_ptes_* handling into helper functions Patch 4: Generalize __collapse_huge_page_* for mTHP support Patch 5: Require collapse_huge_page to enter/exit with the lock dropped Patch 6: Generalize collapse_huge_page for mTHP collapse Patch 7: Skip collapsing mTHP to smaller orders Patch 8-9: Add per-order mTHP statistics and tracepoints Patch 10: Introduce collapse_possible_orders helper functions Patch 11-13: Introduce bitmap and mTHP collapse support, fully enabled Patch 14: Documentation Testing: - Built for x86_64, aarch64, ppc64le, and s390x - ran all arches on test suites provided by the kernel-tests project - internal testing suites: functional testing and performance testing - selftests mm - I created a test script that I used to push khugepaged to its limits while monitoring a number of stats and tracepoints. The code is available here[1] (Run in legacy mode for these changes and set mthp sizes to inherit) The summary from my testings was that there was no significant regression noticed through this test. In some cases my changes had better collapse latencies, and was able to scan more pages in the same amount of time/work, but for the most part the results were consistent. - redis testing. I did some testing with these changes along with my defer changes (see followup [2] post for more details). We've decided to get the mTHP changes merged first before attempting the defer series. - some basic testing on 64k page size. - lots of general use. This patch (of 14): For khugepaged to support different mTHP orders, we must generalize this to check if the PMD is not shared by another VMA and that the order is enabled. We cannot collapse VMA regions that do not span the full PMD. This is due to the potential of the PMD being shared by another VMA which leaves us vulnerable to race conditions if neighboring VMAs are resized. Always check the PMD order here to ensure its not shared by another VMA. We'd need to lock all VMAs in the PMD range to support this which may lead to increased lock contention and code complexity. No functional change in this patch. Also correct a comment about the functionality of the revalidation and fix a double space issues. Link: https://lore.kernel.org/20260605161422.213817-1-npache@redhat.com Link: https://lore.kernel.org/20260605161422.213817-2-npache@redhat.com Link: https://gitlab.com/npache/khugepaged_mthp_test [1] Link: https://lore.kernel.org/lkml/20250515033857.132535-1-npache@redhat.com/ [2] Co-developed-by: Dev Jain <dev.jain@arm.com> Signed-off-by: Dev Jain <dev.jain@arm.com> Signed-off-by: Nico Pache <npache@redhat.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Lorenzo Stoakes <ljs@kernel.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Usama Arif <usama.arif@linux.dev> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Barry Song <baohua@kernel.org> Cc: Brendan Jackman <jackmanb@google.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shivank Garg <shivankg@amd.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Takashi Iwai (SUSE) <tiwai@suse.de> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/page_alloc: only update NUMA min ratios on sysctl writeJianlin Shi
The sysctl handlers for min_unmapped_ratio and min_slab_ratio invoke setup_min_unmapped_ratio() and setup_min_slab_ratio() unconditionally after proc_dointvec_minmax(), even for read operations. These setup functions first zero all per-NUMA node thresholds (min_unmapped_pages and min_slab_pages) before recalculating them. Reading /proc sysctl entries therefore temporarily resets node reclaim thresholds to zero, which may disturb the behavior of __node_reclaim() and node_reclaim() during the recomputation. Fix this by only calling the setup functions when the sysctl is actually written (write == 1), matching the behavior of existing sysctl handlers like min_free_kbytes and watermark_scale_factor. This only affects systems with CONFIG_NUMA. Link: https://lore.kernel.org/tencent_5891052AF9A4C2D490A62F478D446F74AB09@qq.com Signed-off-by: Jianlin Shi <shijianlin11@foxmail.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21zsmalloc: simplify data output in zs_stats_size_show()Markus Elfring
Move the specification for a line break from a seq_puts() call to a seq_printf() call. The source code was transformed by using the Coccinelle software. Link: https://lore.kernel.org/126a924b-6f68-43bf-ae5a-449fb93e527b@web.de Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21lib: split codetag_lock_module_list()Bart Van Assche
Letting a function argument indicate whether a lock or unlock operation should be performed is incompatible with compile-time analysis of locking operations by sparse and Clang. Hence, split codetag_lock_module_list() into two functions: a function that locks cttype->mod_lock and another function that unlocks cttype->mod_lock. No functionality has been changed. See also commit 916cc5167cc6 ("lib: code tagging framework"). Link: https://lore.kernel.org/20260324214226.3684605-1-bvanassche@acm.org Signed-off-by: Bart Van Assche <bvanassche@acm.org> Acked-by: Suren Baghdasaryan <surenb@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21alloc_tag: fix use-after-free in /proc/allocinfo after module unloadHao Ge
allocinfo_start() only reinitializes the codetag iterator at position 0. For subsequent reads (position > 0), it reuses cached iterator state from the previous batch. allocinfo_stop() drops mod_lock between read batches, which allows module unload to complete and free the module memory that the cached iterator still references: CPU0 (read) CPU1 (rmmod) ---- ---- allocinfo_start(pos=0) down_read(mod_lock) allocinfo_show() ... allocinfo_stop() up_read(mod_lock) codetag_unload_module() kfree(cmod) release_module_tags() ... free_mod_mem() allocinfo_start(pos=N) down_read(mod_lock) // reuses cached iter, skips re-init allocinfo_show() ct->filename <-- UAF After free_mod_mem() frees the module's .rodata, allocinfo_show() dereferences ct->filename, ct->function which point there. Save the iterator state in allocinfo_next() and resume from it in allocinfo_start() with codetag_next_ct(), which detects module removal via idr_find() returning NULL and skips to the next module. Link: https://lore.kernel.org/20260604065938.105991-1-hao.ge@linux.dev Fixes: 9f44df50fee4 ("alloc_tag: keep codetag iterator active between read()") Signed-off-by: Hao Ge <hao.ge@linux.dev> Suggested-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Suren Baghdasaryan <surenb@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21mm/alloc_tag: replace fixed-size early PFN array with dynamic linked listHao Ge
Pages allocated before page_ext is available have their codetag left uninitialized. Track these early PFNs and clear their codetag in clear_early_alloc_pfn_tag_refs() to avoid "alloc_tag was not set" warnings when they are freed later. Currently a fixed-size array of 8192 entries is used, with a warning if the limit is exceeded. However, the number of early allocations depends on the number of CPUs and can be larger than 8192. Replace the fixed-size array with a dynamically allocated linked list of pfn_pool structs. Each node is allocated via alloc_page() and mapped to a pfn_pool containing a next pointer, an atomic slot counter, and a PFN array that fills the remainder of the page. The tracking pages themselves are allocated via alloc_page(), which would trigger __pgalloc_tag_add() -> alloc_tag_add_early_pfn() and recurse indefinitely. Introduce __GFP_NO_CODETAG (reuses the %__GFP_NO_OBJ_EXT bit) and pass gfp_flags through pgalloc_tag_add() so that the early path can skip recording allocations that carry this flag. Link: https://lore.kernel.org/20260604024008.46592-1-hao.ge@linux.dev Signed-off-by: Hao Ge <hao.ge@linux.dev> Suggested-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Suren Baghdasaryan <surenb@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds
Pull SCSI updates from James Bottomley: "Only ufs driver updates this time, apart from which this is just an assortment of bug fixes and AI assisted changes. The biggest other change is the reversion of the sas_user_scan patch which supported a mpi3mr NVME behaviour but caused major issues for other sas controllers. The next biggest is the removal of target reset in tcm_loop.c" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (56 commits) scsi: target: Remove tcm_loop target reset handling scsi: lpfc: Fix spelling mistakes in comments scsi: ufs: ufs-pci: Add AMD device ID support scsi: ufs: core: Handle PM commands timeout before SCSI EH scsi: devinfo: Broaden Promise VTrak E310/E610 identification scsi: target: Use constant-time crypto_memneq() for CHAP digests scsi: target: Fix hexadecimal CHAP_I handling scsi: scsi_debug: Fix one-partition tape setup bounds scsi: ufs: qcom: dt-bindings: Document the Hawi UFS controller scsi: mailmap: Update Avri Altman's email address scsi: ufs: Remove redundant vops NULL check and trivial wrapper scsi: ufs: Remove unnecessary return in void vops wrappers scsi: ufs: Fix wrong value printed in unexpected UPIU response case scsi: ufs: core: Fix NULL pointer dereference in scsi_cmd_priv() calls scsi: megaraid_mbox: Avoid double kfree() scsi: pm8001: Fix error code in non_fatal_log_show() scsi: lpfc: Turn lpfc_queue q_pgs into a flexible array scsi: ufs: core: Skip link param validation when lanes_per_direction is unset scsi: sas: Skip opt_sectors when DMA reports no real optimization hint scsi: Revert "scsi: Fix sas_user_scan() to handle wildcard and multi-channel scans" ...
2026-06-21Merge tag '9p-for-7.2-rc1' of https://github.com/martinetd/linuxLinus Torvalds
Pull 9p updates from Dominique Martinet: "Asides of the avalanche of LLM-driven fixes, there are a couple of big changes this cycle: - negative dentry and symlink cache - a way out of the unkillable "io_wait_event_killable" (because it looped around waiting for the request flush to come back from server; this has been bugging syzcaller folks since forever): I'm still not 100% sure about this patch, but I think it's as good as we'll ever get, and will keep testing a bit further in the coming weeks The rest is more noisy than usual, but shouldn't cause any trouble" * tag '9p-for-7.2-rc1' of https://github.com/martinetd/linux: 9p: Add missing read barrier in virtio zero-copy path net/9p: Replace strlen() strcpy() pair with strscpy() 9p: skip nlink update in cacheless mode to fix WARN_ON net/9p: fix race condition on rdma->state in trans_rdma.c 9p: v9fs_file_do_lock: replace WARN_ONCE with p9_debug 9p: Enable symlink caching in page cache 9p: Set default negative dentry retention time for cache=loose 9p: Add mount option for negative dentry cache retention 9p: Cache negative dentries for lookup performance 9p: avoid returning ERR_PTR(0) from mkdir operations 9p: avoid putting oldfid in p9_client_walk() error path net/9p: fix infinite loop in p9_client_rpc on fatal signal docs/filesystems/9p: fix broken external links 9p: invalidate readdir buffer on seek 9p: use kvzalloc for readdir buffer net/9p/usbg: Constify struct configfs_item_operations
2026-06-21Merge tag 'firewire-updates-7.2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394 Pull firewire updates from Takashi Sakamoto: - firewire drivers have been able to assign an arbitrary value in the mod_device entry, which is typed as kernel_ulong_t. While storing the pointer value is legitimate, conversion back to a pointer has been performed without preserving the const qualifier. Uwe Kleine-König introduced an union to provide safer and more robust conversions, as part of the ongoing CHERI enhancement work for ARM and RISC-V architectures. This includes changes to the sound subsystem, since the conversion pattern is widely used in ALSA firewire stack. - Userspace applications can request the core function to perform isochronous resource management procedures. Dingsoul reported a reference-count leak when these procedures are processed in workqueue contexts. This refactors the relevant code paths following a divide and conquer approach. Consequently, it became clear that the issue still remain in the path when userspace applications delegate automatic resource reallocation after bus resets to the core. In practice, the leak is rarely triggered, and a complete fix is still in progress. * tag 'firewire-updates-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394: firewire: core: Open-code topology list walk firewire: core: cancel using delayed work for iso_resource_once management firewire: core: rename member name for channel mask of isoc resource firewire: core: minor code refactoring for case-dependent parameters of iso resources management ALSA: firewire: Make use of ieee1394's .driver_data_ptr firewire: Simplify storing pointers in device id struct firewire: core: move allocation/reallocation paths into specific branch after isoc resource management in cdev firewire: core: refactor notification type determination after isoc resource management in cdev firewire: core: use switch statement for post-processing of isoc resource management in cdev firewire: core: reduce critical section duration in pre-processing of isoc resource management in cdev firewire: core: code cleanup for iso resource auto creation firewire: core: append _auto suffix for non-once iso resource operations firewire: core: code cleanup to remove old implementations for once operation firewire: core: split functions for iso_resource once operation firewire: core: code refactoring for helper function to fill iso_resource parameters firewire: core: code refactoring to queue work item for iso_resource firewire: core: code refactoring for early return at client resource allocation
2026-06-21Merge tag 'liveupdate-v7.2-rc1' of ↵Linus Torvalds
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 ...
2026-06-21Merge tag 'for-linus' of https://github.com/openrisc/linuxLinus Torvalds
Pull OpenRISC updates from Stafford Horne: "A few fixes for text patching related code: - Update the section of map_page used in text patching. It was left with __init when text patching was introduced to OpenRISC - Add fix to invalidate remote SMP core i-caches after text is patched" * tag 'for-linus' of https://github.com/openrisc/linux: openrisc: Fix jump_label smp syncing openrisc: Add full instruction cache invalidate functions openrisc: Cache invalidation cleanup openrisc: mm: Fix section mismatch between map_page and __set_fixmap
2026-06-21Merge tag 'nand/for-7.2' into mtd/nextMiquel Raynal
* Extend SPI NAND continuous read to Winbond devices, which requires numerous changes in the spi-{mem,nand} layers such as the need for a secondary read operation template. * Continuous reads in general have also been enhanced/fixed for avoiding potential issues at probe time and at block boundaries. Plus, there is the usual load of misc fixes and improvements.
2026-06-21Merge tag 'spi-nor/for-7.2' into mtd/nextMiquel Raynal
SPI NOR changes for 7.2 Notable changes: - Big set of cleanups and improvements to the locking support. This series contains some cleanups and bug fixes for code and documentation around write protection. Then support is added for complement locking, which allows finer grained configuration of what is considered locked and unlocked. Then complement locking is enabled on a bunch of Winbond W25 flashes. - Fix die erase support on Spansion flashes. Die erase is only supported on multi-die flashes, but the die erase opcode was set for all. When the opcode is set, it overrides the default chip erase opcode which should be used for single-die flashes. Only set the opcode on multi-die flashes. Also, the opcode was not set on multi-die s28hx-t flashes. Set it so they can use die-erase correctly.
2026-06-21drm/nouveau: fix reversed error cleanup order in ucopy functionsJunrui Luo
nouveau_uvmm_vm_bind_ucopy() and nouveau_exec_ucopy() place their error cleanup labels in allocation order rather than reverse allocation order. On a u_memcpya() failure for in_sync.s, the goto to err_free_ops (or err_free_pushs) frees the first allocation and then falls through to err_free_ins, which calls u_free() on args->in_sync.s. Since args->in_sync.s still holds the ERR_PTR returned by the failed u_memcpya(), and ERR_PTR values are not caught by ZERO_OR_NULL_PTR(), kvfree() proceeds to dereference it, which can result in a kernel oops. A failure for out_sync.s instead jumps to err_free_ins and skips freeing the first allocation, leading to a memory leak. Fix by swapping the cleanup label order so resources are freed in the correct reverse allocation sequence. Fixes: b88baab82871 ("drm/nouveau: implement new VM_BIND uAPI") Reported-by: Yuhao Jiang <danisjiang@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Junrui Luo <moonafterrain@outlook.com> Link: https://patch.msgid.link/SYBPR01MB7881484D91A6F80271415F71AF1A2@SYBPR01MB7881.ausprd01.prod.outlook.com Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-06-21drm/nouveau/acr: fix missing nvkm_done() in error path of nvkm_acr_oneinit()Wentao Liang
In nvkm_acr_oneinit(), nvkm_kmap(acr->wpr) is invoked unconditionally at line 309 to obtain a mapping reference. Additionally, when both acr->wpr_fw and acr->wpr_comp are present, a second nvkm_kmap() is called inside the conditional block. Both mappings are expected to be released by nvkm_done(acr->wpr) at line 320 before the function returns successfully. However, when a mismatch is detected during the loop within the conditional block, the function returns -EINVAL at line 318 without calling nvkm_done(). This results in a leak of the kmap reference(s) acquired earlier. Fix the issue by invoking nvkm_done(acr->wpr) prior to the early return to ensure proper release of the mapping references. Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace "secure boot"") Cc: stable@vger.kernel.org Signed-off-by: Wentao Liang <vulab@iscas.ac.cn> Link: https://patch.msgid.link/20260606155606.77593-1-vulab@iscas.ac.cn Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-06-21irqchip/crossbar: Fix parent domain resource leakBhargav Joshi
irq_domain_alloc_irqs_parent() is called in allocate_gic_irq() but irq_domain_free_irqs_parent() is never called which causes a resource leak. Fix this by calling irq_domain_free_irqs_parent() in crossbar_domain_free(). Fixes: 783d31863fb82 ("irqchip: crossbar: Convert dra7 crossbar to stacked domains") Signed-off-by: Bhargav Joshi <j.bhargav.u@gmail.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260620-irq-crossbar-fix-v2-2-b8e8499f468a@gmail.com
2026-06-21irqchip/crossbar: Use correct index in crossbar_domain_free()Bhargav Joshi
crossbar_domain_free() resets the domain data and then uses the nulled out irq_data->hwirq member as index to reset the irq_map[] entry and to write the relevant crossbar register with a safe entry. That means it never frees the correct index and keeps the crossbar register connection to the source interrupt active. If it would not reset the domain data, then this would be even worse as irq_data->hwirq holds the source interrupt number, but both the map and register index need the corresponding GIC SPI number and not the source interrupt number. This might even result in an out of bounds access as the source interrupt number can be higher than the maximal index space. Fix this by using the GIC SPI index from the parent domain's irq_data. Fixes: 783d31863fb82 ("irqchip: crossbar: Convert dra7 crossbar to stacked domains") Signed-off-by: Bhargav Joshi <j.bhargav.u@gmail.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260620-irq-crossbar-fix-v2-1-b8e8499f468a@gmail.com
2026-06-21locking/rt: Fix the incorrect RCU protection in rt_spin_unlock()Thomas Gleixner
rt_spin_unlock() releases the RCU protection before unlocking the lock. That opens the door for the following UAF scenario: T1 T2 spin_lock(&p->lock); rcu_read_lock(); invalidate(p); p = rcu_dereference(ptr); rcu_assign_pointer(ptr, NULL); if (!p) return; spin_unlock(&p->lock); spin_lock(&p->lock) lock(&lock->lock); rcu_read_lock(); kfree_rcu(p); rcu_read_unlock(); .... spin_unlock(&p->lock) rcu_read_unlock(); // Ends grace period rcu_do_batch() kfree(p); UAF -> rt_mutex_cmpxchg_release(&lock->lock...) Regular spinlocks keep preemption disabled accross the unlock operation, which provides full RCU protection, but the RT substitution fails to resemble that. Same applies for the rwlock substitution. Move the rcu_read_unlock() invocation past the unlock operations to match the non-RT semantics. This makes it asymmetric vs. rt_xxx_lock(), but that's harmless as the caller needs to hold RCU read lock across the lock operation. The migrate_enable() call stays before the unlock operation because there is no per CPU operation in the unlock path which would require migration to be kept disabled. Fixes: 0f383b6dc96e ("locking/spinlock: Provide RT variant") Reported-by: syzbot+000c800a02097aaa10ed@syzkaller.appspotmail.com Decoded-by: Jann Horn <jannh@google.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/87jyrud75z.ffs@fw13
2026-06-20Merge tag 'hwlock-v7.2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux Pull hwspinlock update from Bjorn Andersson: - Avoid uninitialized struct members in the Qualcomm hwspinlock driver * tag 'hwlock-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux: hwspinlock: qcom: avoid uninitialized struct members
2026-06-20Merge tag 'rpmsg-v7.2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux Pull rpmsg update from Bjorn Andersson: - Fix use-after-free in rpmsg-char driver * tag 'rpmsg-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux: rpmsg: char: Fix use-after-free on probe error path
2026-06-20Merge tag 'rproc-v7.2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux Pull remoteproc updates from Bjorn Andersson: - Add i.MX94 support to the i.MX remoteproc driver, covering the Cortex-M7 and Cortex-M33 Sync cores. This also fixes programming of non-zero System Manager CPU/LMM reset vectors. - Move the remoteproc resource table definitions to a separate header, so they can be used by clients that do not otherwise depend on remoteproc. Switch the firmware resource handling over to the common iterator. - Update the Xilinx R5F remoteproc driver to check the remote core state before attaching, drop a binding header dependency, and add firmware-name based auto boot support. - Add Qualcomm Hawi ADSP/CDSP bindings, together with Shikra RPM bindings and CDSP, LPAICP, and MPSS PAS support. Fix a Qualcomm minidump leak, clean up PAS and WCSS reset handling, and make the user-visible Qualcomm naming consistent. - Remove a duplicate STM32_RPROC Kconfig dependency and make i.MX remoteproc instances use the device node name so multiple processors can be distinguished in sysfs. * tag 'rproc-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux: remoteproc: qcom: pas: Drop start/stop completion from struct qcom_pas remoteproc: qcom: pas: Add Shikra remoteproc support dt-bindings: remoteproc: qcom,shikra-pas: Document Shikra PAS remoteprocs dt-bindings: remoteproc: Add Shikra RPM processor compatible remoteproc: qcom: Unify user-visible "Qualcomm" name remoteproc: qcom: Fix leak when custom dump_segments addition fails remoteproc: qcom_q6v5_wcss: drop redundant wcss_q6_bcr_reset dt-bindings: remoteproc: qcom,sm8550-pas: Add Hawi CDSP compatible dt-bindings: remoteproc: qcom,sm8550-pas: Add Hawi ADSP compatible remoteproc: xlnx: Enable auto boot feature dt-bindings: remoteproc: xlnx: Add firmware-name property remoteproc: xlnx: Remove binding header dependency remoteproc: imx_rproc: Use device node name as processor name remoteproc: use rsc_table_for_each_entry() in rproc_handle_resources() remoteproc: Move resource table data structure to its own header remoteproc: xlnx: Check remote core state remoteproc: imx_rproc: Add support for i.MX94 remoteproc: imx_rproc: Program non-zero SM CPU/LMM reset vector dt-bindings: remoteproc: imx-rproc: Support i.MX94 remoteproc: Dead code cleanup in Kconfig for STM32_RPROC
2026-06-219p: Add missing read barrier in virtio zero-copy pathGui-Dong Han
Commit 2b6e72ed747f ("9P: Add memory barriers to protect request fields over cb/rpc threads handoff") added a read barrier after p9_client_rpc() waits for req->status, pairing with the write barrier in p9_client_cb(). The virtio zero-copy wait path was missed. Add the same read barrier after the zero-copy wait before reading the completed request. Fixes: 2b6e72ed747f ("9P: Add memory barriers to protect request fields over cb/rpc threads handoff") Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com> Message-ID: <20260529075441.233369-1-hanguidong02@gmail.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2026-06-21net/9p: Replace strlen() strcpy() pair with strscpy()David Laight
Use the result of strscpy() for the overflow check. Signed-off-by: David Laight <david.laight.linux@gmail.com> Message-ID: <20260606202744.5113-3-david.laight.linux@gmail.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2026-06-219p: skip nlink update in cacheless mode to fix WARN_ONBreno Leitao
v9fs_dec_count() unconditionally calls drop_nlink() on regular files, even when the inode's nlink is already zero. In cacheless mode the client refetches inode metadata from the server (the source of truth) on every operation, so by the time v9fs_remove() returns, the locally cached nlink may already reflect the post-unlink value: 1. Client initiates unlink, server processes it and sets nlink to 0 2. Client refetches inode metadata (nlink=0) before unlink returns 3. Client's v9fs_remove() completes successfully 4. Client calls v9fs_dec_count() which calls drop_nlink() on nlink=0 This race is easily triggered under heavy unlink workloads, such as stress-ng's unlink stressor, producing the following warning: WARNING: fs/inode.c:417 at drop_nlink+0x4c/0xc8 Call trace: drop_nlink+0x4c/0xc8 v9fs_remove+0x1e0/0x250 [9p] v9fs_vfs_unlink+0x20/0x38 [9p] vfs_unlink+0x13c/0x258 ... In cacheless mode the server is authoritative and the inode is on its way out, so locally adjusting nlink buys nothing. Skip v9fs_dec_count() entirely when neither CACHE_META nor CACHE_LOOSE is set, which both avoids the warning and removes a class of nlink races (two concurrent unlinkers observing nlink > 0 and both calling drop_nlink()) that an nlink == 0 guard alone would only narrow rather than close. Fixes: ac89b2ef9b55 ("9p: don't maintain dir i_nlink if the exported fs doesn't either") Cc: stable@vger.kernel.org Suggested-by: Dominique Martinet <asmadeus@codewreck.org> Signed-off-by: Breno Leitao <leitao@debian.org> Message-ID: <20260421-9p-v2-1-48762d294fad@debian.org> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2026-06-21net/9p: fix race condition on rdma->state in trans_rdma.cYizhou Zhao
The rdma->state field is modified without holding req_lock in both recv_done() and p9_cm_event_handler(), while rdma_request() accesses the same field under the req_lock spinlock. This inconsistent locking creates a race condition: - recv_done() running in softirq completion context sets rdma->state = P9_RDMA_FLUSHING without acquiring req_lock - p9_cm_event_handler() modifies rdma->state at multiple points (ADDR_RESOLVED, ROUTE_RESOLVED, ESTABLISHED, CLOSED) without req_lock - rdma_request() uses spin_lock_irqsave(&rdma->req_lock, flags) to protect the read-modify-write of rdma->state The race can cause lost state transitions: recv_done() or the CM event handler could set state to FLUSHING/CLOSED while rdma_request() is concurrently checking or modifying state under the lock, leading to the FLUSHING transition being silently overwritten by CLOSING. This corrupts the connection state machine and can cause use-after-free on RDMA request objects during teardown. Fix by adding req_lock protection to all rdma->state modifications in recv_done() and p9_cm_event_handler(), matching the pattern already used in rdma_request(). Use spin_lock_irqsave/spin_unlock_irqrestore in the CM event handler since it can race with recv_done() which runs in softirq context. Tested with a kernel module that races two threads (simulating rdma_request and recv_done/CM handler) on rdma->state with proper locking: 5.5M+ FLUSHING writes over 27M iterations with 0 lost transitions. Fixes: 473c7dd1d7b5 ("9p/rdma: remove useless check in cm_event_handler") Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn> Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn> Reported-by: Ao Wang <wangao@seu.edu.cn> Reported-by: Xuewei Feng <fengxw06@126.com> Reported-by: Qi Li <qli01@tsinghua.edu.cn> Reported-by: Ke Xu <xuke@tsinghua.edu.cn> Assisted-by: GLM:GLM-5.1 Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn> Message-ID: <20260529073933.77315-1-zhaoyz24@mails.tsinghua.edu.cn> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>