kernel/linux.git/mm/cma.c, branch v7.0.10

mm/cma: move put_page_testzero() out of VM_WARN_ON in cma_release()

2026-03-04T17:44:22+00:00

When CONFIG_DEBUG_VM is not set, VM_WARN_ON is a NOP. Putting any statement with side effect inside it is incorrect. Collect all !put_page_testzero() results and check the sum using WARN instead after the loop. It restores the same check in free_contig_range() before commit e0c1326779cc ("mm: page_alloc: add alloc_contig_frozen_{range,pages}()"), the commit prior to the Fixes one. Link: https://lkml.kernel.org/r/20260225031231.2352011-1-ziy@nvidia.com Fixes: 9bda131c6093 ("mm: cma: add cma_alloc_frozen{_compound}()") Signed-off-by: Zi Yan Reported-by: Ron Economos Closes: https://lore.kernel.org/all/1b17c38f-30d3-4bb4-a7e1-e74b19ada885@w6rz.net/ Suggested-by: Kefeng Wang Reviewed-by: Vishal Moola (Oracle) Debugged-by: David Hildenbrand (Arm) Acked-by: David Hildenbrand (Arm) Tested-by: Ron Economos Reviewed-by: Kefeng Wang Reviewed-by: Anshuman Khandual Reviewed-by: SeongJae Park Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/cma: replace snprintf with strscpy in cma_new_area

2026-02-06T23:47:15+00:00

Replace snprintf("%s", ...) with the faster and more direct strscpy(). Link: https://lkml.kernel.org/r/20260126174516.236968-1-thorsten.blum@linux.dev Signed-off-by: Thorsten Blum Reviewed-by: Andrew Morton Reviewed-by: SeongJae Park Cc: David Hildenbrand Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: cma: add cma_alloc_frozen{_compound}()

2026-01-27T04:02:28+00:00

Introduce cma_alloc_frozen{_compound}() helper to alloc pages without incrementing their refcount, then convert hugetlb cma to use the cma_alloc_frozen_compound() and cma_release_frozen() and remove the unused cma_{alloc,free}_folio(), also move the cma_validate_zones() into mm/internal.h since no outside user. The set_pages_refcounted() is only called to set non-compound pages after above changes, so remove the processing about PageHead. Link: https://lkml.kernel.org/r/20260109093136.1491549-6-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Zi Yan Cc: Brendan Jackman Cc: David Hildenbrand Cc: Jane Chu Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Muchun Song Cc: Oscar Salvador Cc: Sidhartha Kumar Cc: Vlastimil Babka Cc: Claudiu Beznea Cc: Mark Brown Signed-off-by: Andrew Morton

mm: page_alloc: add alloc_contig_frozen_{range,pages}()

2026-01-27T04:02:28+00:00

In order to allocate given range of pages or allocate compound pages without incrementing their refcount, adding two new helper alloc_contig_frozen_{range,pages}() which may be beneficial to some users (eg hugetlb). The new alloc_contig_{range,pages} only take !__GFP_COMP gfp now, and the free_contig_range() is refactored to only free non-compound pages, the only caller to free compound pages in cma_free_folio() is changed accordingly, and the free_contig_frozen_range() is provided to match the alloc_contig_frozen_range(), which is used to free frozen pages. Link: https://lkml.kernel.org/r/20260109093136.1491549-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Zi Yan Reviewed-by: Sidhartha Kumar Cc: Brendan Jackman Cc: David Hildenbrand Cc: Jane Chu Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Muchun Song Cc: Oscar Salvador Cc: Vlastimil Babka Cc: Claudiu Beznea Cc: Mark Brown Signed-off-by: Andrew Morton

mm: cma: kill cma_pages_valid()

2026-01-27T04:02:27+00:00

Kill cma_pages_valid() which only used in cma_release(), also cleanup code duplication between cma pages valid checking and cma memrange finding. Link: https://lkml.kernel.org/r/20260109093136.1491549-4-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Jane Chu Reviewed-by: Zi Yan Reviewed-by: Muchun Song Acked-by: David Hildenbrand Cc: Brendan Jackman Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Oscar Salvador Cc: Sidhartha Kumar Cc: Vlastimil Babka Cc: Claudiu Beznea Cc: Mark Brown Signed-off-by: Andrew Morton

mm/cma: refuse handing out non-contiguous page ranges

2025-09-21T21:22:06+00:00

Let's disallow handing out PFN ranges with non-contiguous pages, so we can remove the nth-page usage in __cma_alloc(), and so any callers don't have to worry about that either when wanting to blindly iterate pages. This is really only a problem in configs with SPARSEMEM but without SPARSEMEM_VMEMMAP, and only when we would cross memory sections in some cases. Will this cause harm? Probably not, because it's mostly 32bit that does not support SPARSEMEM_VMEMMAP. If this ever becomes a problem we could look into allocating the memmap for the memory sections spanned by a single CMA region in one go from memblock. [david@redhat.com: we can have NUMMU configs with SPARSEMEM enabled] Link: https://lkml.kernel.org/r/6ec933b1-b3f7-41c0-95d8-e518bb87375e@redhat.com Link: https://lkml.kernel.org/r/20250901150359.867252-23-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Alexandru Elisei Reviewed-by: Lorenzo Stoakes Signed-off-by: Andrew Morton

mm/cma: add 'available count' and 'total count' to trace_cma_alloc_start

2025-09-13T23:55:15+00:00

This makes cma info more intuitive during debugging. Show up in the trace as: 279.814717: cma_alloc_start: name=reserved request_count=4 available_count=8096 total_count=8192 align=0 309.790580: cma_alloc_start: name=reserved request_count=4 available_count=8092 total_count=8192 align=0 317.046609: cma_alloc_start: name=reserved request_count=4 available_count=8088 total_count=8192 align=0 Link: https://lkml.kernel.org/r/8a79284879c529f467478552825154b018076e95.1755729178.git.gaoxiang17@xiaomi.com Signed-off-by: gaoxiang17 Cc: David Hildenbrand Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: cma: simplify cma_debug_show_areas()

2025-07-25T02:12:36+00:00

The function opencodes for_each_clear_bitrange(). Fix that and drop most of housekeeping code. Link: https://lkml.kernel.org/r/20250719205401.399475-2-yury.norov@gmail.com Signed-off-by: Yury Norov (NVIDIA) Acked-by: David Hildenbrand Signed-off-by: Andrew Morton

cma: move memory allocation to a helper function

2025-07-13T23:38:24+00:00

__cma_declare_contiguous_nid() tries to allocate memory in several ways: * on systems with 64 bit physical address and enough memory it first attempts to allocate memory just above 4GiB * if that fails, on systems with HIGHMEM the next attempt is from high memory * and at last, if none of the previous attempts succeeded, or was even tried because of incompatible configuration, the memory is allocated anywhere within specified limits. Move all the allocation logic to a helper function to make these steps more obvious. Link: https://lkml.kernel.org/r/20250703184711.3485940-4-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: David Hildenbrand Acked-by: Oscar Salvador Cc: Alexandre Ghiti Cc: Pratyush Yadav Signed-off-by: Andrew Morton

cma: split reservation of fixed area into a helper function

2025-07-13T23:38:24+00:00

Move the check that verifies that reservation of fixed area does not cross HIGHMEM boundary and the actual memblock_resrve() call into a helper function. This makes code more readable and decouples logic related to CONFIG_HIGHMEM from the core functionality of __cma_declare_contiguous_nid(). Link: https://lkml.kernel.org/r/20250703184711.3485940-3-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Oscar Salvador Acked-by: David Hildenbrand Cc: Alexandre Ghiti Cc: Pratyush Yadav Signed-off-by: Andrew Morton