The patch titled
Subject: mm, thp: fix leaking mapped pte in __collapse_huge_page_swapin()
has been added to the -mm tree. Its filename is
mm-thp-fix-leaking-mapped-pte-in-__collapse_huge_page_swapin.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-thp-fix-leaking-mapped-pte-in-__collapse_huge_page_swapin.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-fix-leaking-mapped-pte-in-__collapse_huge_page_swapin.patch
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------------------------------------------------------
From: Ebru Akagunduz <ebru.akagunduz@xxxxxxxxx>
Subject: mm, thp: fix leaking mapped pte in __collapse_huge_page_swapin()
Currently, khugepaged does not permit swapin if there are enough young
pages in a THP. The problem is when a THP does not have enough young
pages, khugepaged leaks mapped ptes.
This patch prohibits leaking mapped ptes.
Link: http://lkml.kernel.org/r/1472820276-7831-1-git-send-email-ebru.akagunduz@xxxxxxxxx
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@xxxxxxxxx>
Suggested-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff -puN mm/khugepaged.c~mm-thp-fix-leaking-mapped-pte-in-__collapse_huge_page_swapin mm/khugepaged.c
--- a/mm/khugepaged.c~mm-thp-fix-leaking-mapped-pte-in-__collapse_huge_page_swapin
+++ a/mm/khugepaged.c
@@ -881,6 +881,11 @@ static bool __collapse_huge_page_swapin(
.pmd = pmd,
};
+ /* we only decide to swapin, if there is enough young ptes */
+ if (referenced < HPAGE_PMD_NR/2) {
+ trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
+ return false;
+ }
fe.pte = pte_offset_map(pmd, address);
for (; fe.address < address + HPAGE_PMD_NR*PAGE_SIZE;
fe.pte++, fe.address += PAGE_SIZE) {
@@ -888,11 +893,6 @@ static bool __collapse_huge_page_swapin(
if (!is_swap_pte(pteval))
continue;
swapped_in++;
- /* we only decide to swapin, if there is enough young ptes */
- if (referenced < HPAGE_PMD_NR/2) {
- trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
- return false;
- }
ret = do_swap_page(&fe, pteval);
/* do_swap_page returns VM_FAULT_RETRY with released mmap_sem */
_
Patches currently in -mm which might be from ebru.akagunduz@xxxxxxxxx are
mm-thp-fix-leaking-mapped-pte-in-__collapse_huge_page_swapin.patch
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