The patch titled
Subject: khugepaged: drain LRU add pagevec after swapin
has been added to the -mm tree. Its filename is
khugepaged-drain-lru-add-pagevec-after-swapin.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/khugepaged-drain-lru-add-pagevec-after-swapin.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/khugepaged-drain-lru-add-pagevec-after-swapin.patch
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From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: khugepaged: drain LRU add pagevec after swapin
__collapse_huge_page_isolate() may fail due to extra pin in the LRU add
pagevec. It's pretty common for swapin case: we swap in pages just to
fail due to the extra pin.
Drain LRU add pagevec on successful swapin.
Link: http://lkml.kernel.org/r/20200416160026.16538-5-kirill.shutemov@xxxxxxxxxxxxxxx
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>
Tested-by: Zi Yan <ziy@xxxxxxxxxx>
Acked-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/mm/khugepaged.c~khugepaged-drain-lru-add-pagevec-after-swapin
+++ a/mm/khugepaged.c
@@ -931,6 +931,11 @@ static bool __collapse_huge_page_swapin(
}
vmf.pte--;
pte_unmap(vmf.pte);
+
+ /* Drain LRU add pagevec to remove extra pin on the swapped in pages */
+ if (swapped_in)
+ lru_add_drain();
+
trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 1);
return true;
}
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
khugepaged-add-self-test.patch
khugepaged-do-not-stop-collapse-if-less-than-half-ptes-are-referenced.patch
khugepaged-drain-all-lru-caches-before-scanning-pages.patch
khugepaged-drain-lru-add-pagevec-after-swapin.patch
khugepaged-allow-to-collapse-a-page-shared-across-fork.patch
khugepaged-allow-to-collapse-pte-mapped-compound-pages.patch
thp-change-cow-semantics-for-anon-thp.patch
khugepaged-introduce-max_ptes_shared-tunable.patch
