From: Balbir Singh <bsingharora@gmail.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: linux-mm@kvack.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] memcg: change memcg_oom_mutex to spinlock
Date: Wed, 20 Jul 2011 12:04:17 +0530 [thread overview]
Message-ID: <CAKTCnzkiRW3aLwnCYyb9XPfTZWipqcA5Jd7d27rZpecqn3wFuQ@mail.gmail.com> (raw)
In-Reply-To: <b24894c23d0bb06f849822cb30726b532ea3a4c5.1310732789.git.mhocko@suse.cz>
On Thu, Jul 14, 2011 at 8:59 PM, Michal Hocko <mhocko@suse.cz> wrote:
> memcg_oom_mutex is used to protect memcg OOM path and eventfd interface
> for oom_control. None of the critical sections which it protects sleep
> (eventfd_signal works from atomic context and the rest are simple linked
> list resp. oom_lock atomic operations).
> Mutex is also too heavy weight for those code paths because it triggers
> a lot of scheduling. It also makes makes convoying effects more visible
> when we have a big number of oom killing because we take the lock
> mutliple times during mem_cgroup_handle_oom so we have multiple places
> where many processes can sleep.
>
> Signed-off-by: Michal Hocko <mhocko@suse.cz>
Quick question: How long do we expect this lock to be taken? What
happens under oom? Any tests? Numbers?
Balbir Singh
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next prev parent reply other threads:[~2011-07-20 6:34 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-15 12:26 [PATCH 0/2 v2 ] memcg: oom locking updates Michal Hocko
2011-07-13 11:05 ` [PATCH 1/2 v2] memcg: make oom_lock 0 and 1 based rather than coutner Michal Hocko
2011-07-21 20:58 ` Andrew Morton
2011-07-22 0:15 ` KAMEZAWA Hiroyuki
2011-08-09 14:03 ` Johannes Weiner
2011-08-09 15:22 ` Michal Hocko
2011-08-09 15:37 ` Johannes Weiner
2011-08-09 15:43 ` Michal Hocko
2011-08-10 0:22 ` KAMEZAWA Hiroyuki
2011-07-14 15:29 ` [PATCH 2/2] memcg: change memcg_oom_mutex to spinlock Michal Hocko
2011-07-20 5:55 ` KAMEZAWA Hiroyuki
2011-07-20 7:01 ` Michal Hocko
2011-07-20 6:34 ` Balbir Singh [this message]
2011-07-20 7:00 ` Michal Hocko
-- strict thread matches above, loose matches on Subject: below --
2011-07-13 12:44 [PATCH 0/2] memcg: oom locking updates Michal Hocko
2011-07-13 12:32 ` [PATCH 2/2] memcg: change memcg_oom_mutex to spinlock Michal Hocko
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