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Patch series "mm: convert to walk_page_range_vma() to eliminate find_vma()", v2. walk_page_range() performs a find_vma() lookup on each page table walk. For callers that already hold a valid VMA and operate on a known single-VMA range, this lookup is redundant. Replace walk_page_range() with walk_page_range_vma() where the caller guarantees single-VMA semantics. This patch (of 4): do_mincore() uses walk_page_range() to walk the page table. Fortunately, the caller always passes start/end that falls within a single VMA, so it's safe to use the walk_page_range_vma() in do_mincore() to eliminate an unnecessary find_vma() lookup. Unlike walk_page_range(), walk_page_range_vma() does not call walk_page_test(), which handles VM_PFNMAP by invoking ->pte_hole() to skip the page table walk. Without this check, PFNMAP PTEs would be treated as present by mincore_pte_range(), changing the returned residency status. Handle VM_PFNMAP explicitly in do_mincore() to preserve the original behavior. [akpm@linux-foundation.org: simplify comment, per Pedro] Link: https://lore.kernel.org/ajP9bQhmvR9OX0VE@pedro-suse Link: https://lore.kernel.org/20260618092845.3905740-1-wangkefeng.wang@huawei.com Link: https://lore.kernel.org/20260618092845.3905740-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Cc: Alistair Popple <apopple@nvidia.com> Cc: Byungchul Park <byungchul@sk.com> Cc: Gregory Price <gourry@gourry.net> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: Ying Huang <ying.huang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
351 lines
8.6 KiB
351 lines
8.6 KiB