diff options
| author | Huang Ying <[email protected]> | 2017-09-06 16:22:41 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2017-09-06 17:27:28 -0700 |
| commit | abe2895b76047bf5430990f2584cd91f76692218 (patch) | |
| tree | 8b30acc88b7b14e4c103593b18ea2ded1a472425 | |
| parent | 3e14a57b2416b7c94189b95baffd673cf5e0d0a3 (diff) | |
memcg, THP, swap: avoid to duplicated charge THP in swap cache
For a THP (Transparent Huge Page), tail_page->mem_cgroup is NULL. So to
check whether the page is charged already, we need to check the head
page. This is not an issue before because it is impossible for a THP to
be in the swap cache before. But after we add delaying splitting THP
after swapped out support, it is possible now.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: "Huang, Ying" <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: "Kirill A . Shutemov" <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Ross Zwisler <[email protected]> [for brd.c, zram_drv.c, pmem.c]
Cc: Shaohua Li <[email protected]>
Cc: Vishal L Verma <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | mm/memcontrol.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2ae315e4d9f6..e7f47a38fe4f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5430,7 +5430,7 @@ int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, * in turn serializes uncharging. */ VM_BUG_ON_PAGE(!PageLocked(page), page); - if (page->mem_cgroup) + if (compound_head(page)->mem_cgroup) goto out; if (do_swap_account) { |