Re: [PATCH V5 3/8] memcg: check for proper lock held in mem_cgroup_update_page_stat
From: Greg Thelen <hidden>
Date: 2013-08-04 18:48:20
Also in:
linux-mm
On Thu, Aug 01 2013, Sha Zhengju wrote:
From: Sha Zhengju <redacted> We should call mem_cgroup_begin_update_page_stat() before mem_cgroup_update_page_stat() to get proper locks, however the latter doesn't do any checking that we use proper locking, which would be hard. Suggested by Michal Hock we could at least test for
^^ Hocko
rcu_read_lock_held() because RCU is held if !mem_cgroup_disabled(). Signed-off-by: Sha Zhengju <redacted>
Reviewed-by: Greg Thelen <redacted>
quoted hunk ↗ jump to hunk
--- mm/memcontrol.c | 1 + 1 file changed, 1 insertion(+)diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7691cef..4a55d46 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c@@ -2301,6 +2301,7 @@ void mem_cgroup_update_page_stat(struct page *page, if (mem_cgroup_disabled()) return; + VM_BUG_ON(!rcu_read_lock_held()); memcg = pc->mem_cgroup; if (unlikely(!memcg || !PageCgroupUsed(pc))) return;