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From: Michal Hocko <mhocko@suse.cz>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: linux-mm@kvack.org, Balbir Singh <bsingharora@gmail.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 09:01:05 +0200	[thread overview]
Message-ID: <20110720070105.GC10857@tiehlicka.suse.cz> (raw)
In-Reply-To: <20110720145553.7703dbcb.kamezawa.hiroyu@jp.fujitsu.com>

On Wed 20-07-11 14:55:53, KAMEZAWA Hiroyuki wrote:
> On Thu, 14 Jul 2011 17:29:51 +0200
> 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>
> 
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Thanks!

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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  reply	other threads:[~2011-07-20  7:01 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 [this message]
2011-07-20  6:34   ` Balbir Singh
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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