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| author | Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> | 2009-04-30 15:08:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-05-02 15:36:09 -0700 |
| commit | c0bd3f63ce01a1757dbce6373122a05fbf99ced7 (patch) | |
| tree | 4034e701106d1ed819441f4f32a04dfa020398ae /mm/memcontrol.c | |
| parent | 1e50cc9022d6c0b9175d804573e3f401d00d1381 (diff) | |
| download | lwn-c0bd3f63ce01a1757dbce6373122a05fbf99ced7.tar.gz lwn-c0bd3f63ce01a1757dbce6373122a05fbf99ced7.zip | |
memcg: fix try_get_mem_cgroup_from_swapcache()
This is a bugfix for commit 3c776e64660028236313f0e54f3a9945764422df
("memcg: charge swapcache to proper memcg").
Used bit of swapcache is solid under page lock, but considering
move_account, pc->mem_cgroup is not.
We need lock_page_cgroup() anyway.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.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 e44fb0fbb80e..575203ae2109 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1024,9 +1024,7 @@ static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page) return NULL; pc = lookup_page_cgroup(page); - /* - * Used bit of swapcache is solid under page lock. - */ + lock_page_cgroup(pc); if (PageCgroupUsed(pc)) { mem = pc->mem_cgroup; if (mem && !css_tryget(&mem->css)) @@ -1040,6 +1038,7 @@ static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page) mem = NULL; rcu_read_unlock(); } + unlock_page_cgroup(pc); return mem; } |