The patch titled
Subject: mm: khugepaged: better comments for anon vma check in hugepage_vma_revalidate
has been added to the -mm mm-unstable branch. Its filename is
mm-khugepaged-better-comments-for-anon-vma-check-in-hugepage_vma_revalidate.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-khugepaged-better-comments-for-anon-vma-check-in-hugepage_vma_revalidate.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Yang Shi <shy828301@xxxxxxxxx>
Subject: mm: khugepaged: better comments for anon vma check in hugepage_vma_revalidate
Date: Wed, 15 Jun 2022 10:29:22 -0700
The hugepage_vma_revalidate() needs to check if the vma is still anonymous
vma or not since the address may be unmapped then remapped to file before
khugepaged reaquired the mmap_lock.
The old comment is not quite helpful, elaborate this with better
comment.
Link: https://lkml.kernel.org/r/20220615172926.546974-4-shy828301@xxxxxxxxx
Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/mm/khugepaged.c~mm-khugepaged-better-comments-for-anon-vma-check-in-hugepage_vma_revalidate
+++ a/mm/khugepaged.c
@@ -954,7 +954,13 @@ static int hugepage_vma_revalidate(struc
return SCAN_ADDRESS_RANGE;
if (!hugepage_vma_check(vma, vma->vm_flags))
return SCAN_VMA_CHECK;
- /* Anon VMA expected */
+ /*
+ * Anon VMA expected, the address may be unmapped then
+ * remapped to file after khugepaged reaquired the mmap_lock.
+ *
+ * hugepage_vma_check may return true for qualified file
+ * vmas.
+ */
if (!vma->anon_vma || !vma_is_anonymous(vma))
return SCAN_VMA_CHECK;
return 0;
_
Patches currently in -mm which might be from shy828301@xxxxxxxxx are
mm-rmap-use-the-correct-parameter-name-for-define_page_vma_walk.patch
mm-pvmw-check-possible-huge-pmd-map-by-transhuge_vma_suitable.patch
mm-khugepaged-check-thp-flag-in-hugepage_vma_check.patch
mm-thp-consolidate-vma-size-check-to-transhuge_vma_suitable.patch
mm-khugepaged-better-comments-for-anon-vma-check-in-hugepage_vma_revalidate.patch
mm-thp-kill-transparent_hugepage_active.patch
mm-thp-kill-__transhuge_page_enabled.patch
mm-khugepaged-reorg-some-khugepaged-helpers.patch
doc-proc-fix-the-description-to-thpeligible.patch
