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| author | Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> | 2011-01-13 15:47:43 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-13 17:32:51 -0800 |
| commit | 50de1dd967d4ba3b8a90ebe7a4f5feca24191317 (patch) | |
| tree | ed2aa4352ae3c2887a90ef6279588a7048397d1b /mm/memcontrol.c | |
| parent | 17295c88a160c6eea3fcf46cec9d08a0fcb02db9 (diff) | |
| download | lwn-50de1dd967d4ba3b8a90ebe7a4f5feca24191317.tar.gz lwn-50de1dd967d4ba3b8a90ebe7a4f5feca24191317.zip | |
memcg: fix memory migration of shmem swapcache
In the current implementation mem_cgroup_end_migration() decides whether
the page migration has succeeded or not by checking "oldpage->mapping".
But if we are tring to migrate a shmem swapcache, the page->mapping of it
is NULL from the begining, so the check would be invalid. As a result,
mem_cgroup_end_migration() assumes the migration has succeeded even if
it's not, so "newpage" would be freed while it's not uncharged.
This patch fixes it by passing mem_cgroup_end_migration() the result of
the page migration.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6424ba0fce83..8ab841031436 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2896,7 +2896,7 @@ int mem_cgroup_prepare_migration(struct page *page, /* remove redundant charge if migration failed*/ void mem_cgroup_end_migration(struct mem_cgroup *mem, - struct page *oldpage, struct page *newpage) + struct page *oldpage, struct page *newpage, bool migration_ok) { struct page *used, *unused; struct page_cgroup *pc; @@ -2905,8 +2905,7 @@ void mem_cgroup_end_migration(struct mem_cgroup *mem, return; /* blocks rmdir() */ cgroup_exclude_rmdir(&mem->css); - /* at migration success, oldpage->mapping is NULL. */ - if (oldpage->mapping) { + if (!migration_ok) { used = oldpage; unused = newpage; } else { |