From a0cb18a120ad6e457375a437f28d3d23878c9d9e Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Thu, 19 May 2022 14:08:49 -0700 Subject: [PATCH] mm: khugepaged: skip DAX vma The DAX vma may be seen by khugepaged when the mm has other khugepaged suitable vmas. So khugepaged may try to collapse THP for DAX vma, but it will fail due to page sanity check, for example, page is not on LRU. So it is not harmful, but it is definitely pointless to run khugepaged against DAX vma, so skip it in early check. Link: https://lkml.kernel.org/r/20220510203222.24246-4-shy828301@gmail.com Signed-off-by: Yang Shi Reviewed-by: Miaohe Lin Acked-by: Song Liu Acked-by: Vlastmil Babka Cc: Kirill A. Shutemov Cc: Matthew Wilcox (Oracle) Cc: Rik van Riel Cc: Song Liu Cc: Theodore Ts'o Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/khugepaged.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index e53b4826c7bd5..647efd46b3698 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -447,6 +447,10 @@ static bool hugepage_vma_check(struct vm_area_struct *vma, if (vm_flags & VM_NO_KHUGEPAGED) return false; + /* Don't run khugepaged against DAX vma */ + if (vma_is_dax(vma)) + return false; + if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff, HPAGE_PMD_NR)) return false; -- 2.39.5