kernel/git/stable/linux.git/mm/page_isolation.c, branch linux-7.2.y

mm: page_isolation: avoid unsafe folio reads while scanning compound pages

2026-06-21T18:37:36+00:00

page_is_unmovable() can inspect compound pages without holding a folio reference or any lock. The folio can therefore be freed, split or reused while the scanner is still looking at it. The existing HugeTLB handling already avoids folio_hstate() for this reason, but it still derives the hstate from folio_size() and later derives the scan step from folio_nr_pages() and folio_page_idx(). These helpers rely on the folio still being a valid folio head. If the folio changed concurrently, the scanner can read inconsistent folio metadata and compute a wrong step. In the worst case, folio_nr_pages() can return 1 for what used to be a tail page and the subtraction from folio_page_idx() can underflow. There is a similar issue for non-Hugetlb compound pages: folio_test_lru() expects a valid folio. If the previously observed head page has been reused as a tail page of another compound page, the folio flag checks can trigger VM_BUG_ON_PGFLAGS(). Read the compound order once with compound_order(), reject obviously bogus orders, and derive the hstate and scan step from that order instead of querying folio size information again. Also use PageLRU(page), which is safe for the page being scanned, instead of folio_test_lru() on a potentially stale folio pointer. Treat an unknown HugeTLB hstate as unmovable so the scanner does not try to skip over an unstable HugeTLB folio. Link: https://lore.kernel.org/20260602130755.38794-1-kaitao.cheng@linux.dev Fixes: a0a9f2180b90 ("mm: page_isolation: avoid calling folio_hstate() without hugetlb_lock") Signed-off-by: Kaitao Cheng Reviewed-by: Zi Yan Acked-by: David Hildenbrand (Arm) Acked-by: Oscar Salvador (SUSE) Cc: Brendan Jackman Cc: Johannes Weiner Cc: Liu Shixin Cc: Michal Hocko Cc: Muchun Song Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: use zone lock guard in set_migratetype_isolate()

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

Use spinlock_irqsave scoped lock guard in set_migratetype_isolate() to replace the explicit lock/unlock pattern with automatic scope-based cleanup. The scoped variant is used to keep dump_page() outside the locked section to avoid a lockdep splat. Link: https://lore.kernel.org/6883351ad7f74d20875fff30e0e3214a089cea97.1777462630.git.d@ilvokhin.com Signed-off-by: Dmitry Ilvokhin Suggested-by: Steven Rostedt Acked-by: Michal Hocko Acked-by: Zi Yan Cc: Brendan Jackman Cc: David Hildenbrand Cc: Johannes Weiner Cc: Lorenzo Stoakes Cc: Peter Zijlstra Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: use zone lock guard in unset_migratetype_isolate()

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

Use spinlock_irqsave zone lock guard in unset_migratetype_isolate() to replace the explicit lock/unlock and goto pattern with automatic scope-based cleanup. Link: https://lore.kernel.org/815c0905ea77828ed32bf56ff0a6d3c6548eb3a2.1777462630.git.d@ilvokhin.com Signed-off-by: Dmitry Ilvokhin Suggested-by: Steven Rostedt Acked-by: Michal Hocko Acked-by: Zi Yan Cc: Brendan Jackman Cc: David Hildenbrand Cc: Johannes Weiner Cc: Lorenzo Stoakes Cc: Peter Zijlstra Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: page_isolation: introduce page_is_unmovable()

2026-01-31T22:22:42+00:00

Patch series "mm: accelerate gigantic folio allocation". Optimize pfn_range_valid_contig() and replace_free_hugepage_folios() in alloc_contig_frozen_pages() to speed up gigantic folio allocation. The allocation time for 120*1G folios drops from 3.605s to 0.431s. This patch (of 5): Factor out the check if a page is unmovable into a new helper, and will be reused in the following patch. No functional change intended, the minor changes are as follows, 1) Avoid unnecessary calls by checking CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION 2) Directly call PageCompound since PageTransCompound may be dropped 3) Using folio_test_hugetlb() Link: https://lkml.kernel.org/r/20260112150954.1802953-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20260112150954.1802953-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Zi Yan Reviewed-by: Oscar Salvador Cc: Brendan Jackman Cc: David Hildenbrand Cc: Jane Chu Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Muchun Song Cc: Sidhartha Kumar Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: fix minor spelling mistakes in comments

2026-01-21T03:24:48+00:00

Correct several typos in comments across files in mm/ [akpm@linux-foundation.org: also fix comment grammar, per SeongJae] Link: https://lkml.kernel.org/r/20251218150906.25042-1-klourencodev@gmail.com Signed-off-by: Kevin Lourenco Reviewed-by: SeongJae Park Acked-by: David Hildenbrand (Red Hat) Reviewed-by: Lorenzo Stoakes Signed-off-by: Andrew Morton

mm/page_isolation: drop __folio_test_movable() check for large folios

2025-07-13T23:38:29+00:00

Currently, we only support migration of individual movable_ops pages, so we can not run into that. Link: https://lkml.kernel.org/r/20250704102524.326966-18-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Zi Yan Reviewed-by: Lorenzo Stoakes Reviewed-by: Harry Yoo Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Brendan Jackman Cc: Byungchul Park Cc: Chengming Zhou Cc: Christian Brauner Cc: Christophe Leroy Cc: Eugenio Pé rez Cc: Greg Kroah-Hartman Cc: Gregory Price Cc: "Huang, Ying" Cc: Jan Kara Cc: Jason Gunthorpe Cc: Jason Wang Cc: Jerrin Shaji George Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joshua Hahn Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Michal Hocko Cc: Mike Rapoport Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Cc: Qi Zheng Cc: Rakie Kim Cc: Rik van Riel Cc: Sergey Senozhatsky Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: xu xin Signed-off-by: Andrew Morton

mm: rename __PageMovable() to page_has_movable_ops()

2025-07-13T23:38:29+00:00

Let's make it clearer that we are talking about movable_ops pages. While at it, convert a VM_BUG_ON to a VM_WARN_ON_ONCE_PAGE. Link: https://lkml.kernel.org/r/20250704102524.326966-17-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Zi Yan Reviewed-by: Lorenzo Stoakes Reviewed-by: Harry Yoo Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Brendan Jackman Cc: Byungchul Park Cc: Chengming Zhou Cc: Christian Brauner Cc: Christophe Leroy Cc: Eugenio Pé rez Cc: Greg Kroah-Hartman Cc: Gregory Price Cc: "Huang, Ying" Cc: Jan Kara Cc: Jason Gunthorpe Cc: Jason Wang Cc: Jerrin Shaji George Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joshua Hahn Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Michal Hocko Cc: Mike Rapoport Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Cc: Qi Zheng Cc: Rakie Kim Cc: Rik van Riel Cc: Sergey Senozhatsky Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Xuan Zhuo Cc: xu xin Signed-off-by: Andrew Morton

mm/page_isolation: remove migratetype parameter from more functions

2025-07-13T23:38:18+00:00

migratetype is no longer overwritten during pageblock isolation, start_isolate_page_range(), has_unmovable_pages(), and set_migratetype_isolate() no longer need which migratetype to restore during isolation failure. For has_unmoable_pages(), it needs to know if the isolation is for CMA allocation, so adding PB_ISOLATE_MODE_CMA_ALLOC provide the information. At the same time change isolation flags to enum pb_isolate_mode (PB_ISOLATE_MODE_MEM_OFFLINE, PB_ISOLATE_MODE_CMA_ALLOC, PB_ISOLATE_MODE_OTHER). Remove REPORT_FAILURE and check PB_ISOLATE_MODE_MEM_OFFLINE, since only PB_ISOLATE_MODE_MEM_OFFLINE reports isolation failures. alloc_contig_range() no longer needs migratetype. Replace it with a newly defined acr_flags_t to tell if an allocation is for CMA. So does __alloc_contig_migrate_range(). Add ACR_FLAGS_NONE (set to 0) to indicate ordinary allocations. Link: https://lkml.kernel.org/r/20250617021115.2331563-7-ziy@nvidia.com Signed-off-by: Zi Yan Reviewed-by: Vlastimil Babka Acked-by: David Hildenbrand Cc: Baolin Wang Cc: Brendan Jackman Cc: Johannes Weiner Cc: Kirill A. Shuemov Cc: Mel Gorman Cc: Michal Hocko Cc: Oscar Salvador Cc: Richard Chang Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton

mm/page_isolation: remove migratetype from undo_isolate_page_range()

2025-07-13T23:38:18+00:00

Since migratetype is no longer overwritten during pageblock isolation, undoing pageblock isolation no longer needs which migratetype to restore. Link: https://lkml.kernel.org/r/20250617021115.2331563-6-ziy@nvidia.com Signed-off-by: Zi Yan Acked-by: David Hildenbrand Reviewed-by: Vlastimil Babka Cc: Baolin Wang Cc: Brendan Jackman Cc: Johannes Weiner Cc: Kirill A. Shuemov Cc: Mel Gorman Cc: Michal Hocko Cc: Oscar Salvador Cc: Richard Chang Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton

mm/page_isolation: remove migratetype from move_freepages_block_isolate()

2025-07-13T23:38:18+00:00

Since migratetype is no longer overwritten during pageblock isolation, moving a pageblock out of MIGRATE_ISOLATE no longer needs a new migratetype. Add pageblock_isolate_and_move_free_pages() and pageblock_unisolate_and_move_free_pages() to be explicit about the page isolation operations. Both share the common code in __move_freepages_block_isolate(), which is renamed from move_freepages_block_isolate(). Add toggle_pageblock_isolate() to flip pageblock isolation bit in __move_freepages_block_isolate(). Make set_pageblock_migratetype() only accept non MIGRATE_ISOLATE types, so that one should use set_pageblock_isolate() to isolate pageblocks. As a result, move pageblock migratetype code out of __move_freepages_block(). Link: https://lkml.kernel.org/r/20250617021115.2331563-5-ziy@nvidia.com Signed-off-by: Zi Yan Reviewed-by: Vlastimil Babka Acked-by: David Hildenbrand Cc: Baolin Wang Cc: Brendan Jackman Cc: Johannes Weiner Cc: Kirill A. Shuemov Cc: Mel Gorman Cc: Michal Hocko Cc: Oscar Salvador Cc: Richard Chang Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton