linux/mm/page_alloc.c, branch v6.17

mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info()

2025-07-26T22:08:22Z

The trace event has not recorded the right data since it was introduced at commit c8b360031218 ("mm: add alloc_contig_migrate_range allocation statistics"). Remove it. Link: https://lkml.kernel.org/r/20250722194649.4135191-1-ziy@nvidia.com Signed-off-by: Zi Yan Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202507220742.P3SaKlI6-lkp@intel.com/ Acked-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Brendan Jackman Cc: David Rientjes Cc: Johannes Weiner Cc: Martin Liu Cc: "Masami Hiramatsu (Google)" Cc: Mathieu Desnoyers Cc: Michal Hocko Cc: Richard Chang Cc: Steven Rostedt Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton

mm/page-alloc: remove PageMappingFlags()

2025-07-13T23:38:30Z

As PageMappingFlags() now only indicates anon (incl. KSM) folios, we can now simply check for PageAnon() and remove PageMappingFlags(). ... and while at it, use the folio instead and operate on folio->mapping. Link: https://lkml.kernel.org/r/20250704102524.326966-24-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()

2025-07-13T23:38:29Z

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_alloc: let page freeing clear any set page type

2025-07-13T23:38:26Z

Currently, any user of page types must clear that type before freeing a page back to the buddy, otherwise we'll run into mapcount related sanity checks (because the page type currently overlays the page mapcount). Let's allow for not clearing the page type by page type users by letting the buddy handle it instead. We'll focus on having a page type set on the first page of a larger allocation only. With this change, we can reliably identify typed folios even though they might be in the process of getting freed, which will come in handy in migration code (at least in the transition phase). In the future we might want to warn on some page types. Instead of having an "allow list", let's rather wait until we know about once that should go on such a "disallow list". Link: https://lkml.kernel.org/r/20250704102524.326966-5-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Zi Yan Acked-by: Harry Yoo Reviewed-by: Lorenzo Stoakes 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

2025-07-13T23:38:18Z

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()

2025-07-13T23:38:18Z

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()

2025-07-13T23:38:18Z

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

mm/page_alloc: add support for initializing pageblock as isolated

2025-07-13T23:38:17Z

MIGRATE_ISOLATE is a standalone bit, so a pageblock cannot be initialized to just MIGRATE_ISOLATE. Add init_pageblock_migratetype() to enable initialize a pageblock with a migratetype and isolated. Link: https://lkml.kernel.org/r/20250617021115.2331563-4-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: make page isolation a standalone bit

2025-07-13T23:38:17Z

During page isolation, the original migratetype is overwritten, since MIGRATE_* are enums and stored in pageblock bitmaps. Change MIGRATE_ISOLATE to be stored a standalone bit, PB_migrate_isolate, like PB_compact_skip, so that migratetype is not lost during pageblock isolation. Link: https://lkml.kernel.org/r/20250617021115.2331563-3-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_alloc: pageblock flags functions clean up

2025-07-13T23:38:17Z

Patch series "Make MIGRATE_ISOLATE a standalone bit", v10. This patchset moves MIGRATE_ISOLATE to a standalone bit to avoid being overwritten during pageblock isolation process. Currently, MIGRATE_ISOLATE is part of enum migratetype (in include/linux/mmzone.h), thus, setting a pageblock to MIGRATE_ISOLATE overwrites its original migratetype. This causes pageblock migratetype loss during alloc_contig_range() and memory offline, especially when the process fails due to a failed pageblock isolation and the code tries to undo the finished pageblock isolations. In terms of performance for changing pageblock types, no performance change is observed: 1. I used perf to collect stats of offlining and onlining all memory of a 40GB VM 10 times and see that get_pfnblock_flags_mask() and set_pfnblock_flags_mask() take about 0.12% and 0.02% of the whole process respectively with and without this patchset across 3 runs. 2. I used perf to collect stats of dd from /dev/random to a 40GB tmpfs file and find get_pfnblock_flags_mask() takes about 0.05% of the process with and without this patchset across 3 runs. This patch (of 6): No functional change is intended. 1. Add __NR_PAGEBLOCK_BITS for the number of pageblock flag bits and use roundup_pow_of_two(__NR_PAGEBLOCK_BITS) as NR_PAGEBLOCK_BITS to take right amount of bits for pageblock flags. 2. Rename PB_migrate_skip to PB_compact_skip. 3. Add {get,set,clear}_pfnblock_bit() to operate one a standalone bit, like PB_compact_skip. 3. Make {get,set}_pfnblock_flags_mask() internal functions and use {get,set}_pfnblock_migratetype() for pageblock migratetype operations. 4. Move pageblock flags common code to get_pfnblock_bitmap_bitidx(). 3. Use MIGRATETYPE_MASK to get the migratetype of a pageblock from its flags. 4. Use PB_migrate_end in the definition of MIGRATETYPE_MASK instead of PB_migrate_bits. 5. Add a comment on is_migrate_cma_folio() to prevent one from changing it to use get_pageblock_migratetype() and causing issues. Link: https://lkml.kernel.org/r/20250617021115.2331563-1-ziy@nvidia.com Link: https://lkml.kernel.org/r/20250617021115.2331563-2-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