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authorEbru Akagunduz <ebru.akagunduz@gmail.com>2016-09-19 14:44:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-09-19 15:36:16 -0700
commit982785c6b05a82c01e90687b7e25ee87c8970b2e (patch)
treed855120e0185c802dcb3c222fc94abe31a279b3c /mm
parentc131f751ab1a852d4dd4b490b3a7fbba7d738de5 (diff)
downloadlinux-stericsson-982785c6b05a82c01e90687b7e25ee87c8970b2e.tar.gz
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@gmail.com Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com> Suggested-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/khugepaged.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 62339bf3c726..728d7790dc2d 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -882,6 +882,11 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
.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) {
@@ -889,11 +894,6 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
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 */