From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751307Ab1GTHBI (ORCPT ); Wed, 20 Jul 2011 03:01:08 -0400 Received: from cantor2.suse.de ([195.135.220.15]:35452 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750941Ab1GTHBH (ORCPT ); Wed, 20 Jul 2011 03:01:07 -0400 Date: Wed, 20 Jul 2011 09:01:05 +0200 From: Michal Hocko To: KAMEZAWA Hiroyuki Cc: linux-mm@kvack.org, Balbir Singh , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] memcg: change memcg_oom_mutex to spinlock Message-ID: <20110720070105.GC10857@tiehlicka.suse.cz> References: <20110720145553.7703dbcb.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110720145553.7703dbcb.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 20-07-11 14:55:53, KAMEZAWA Hiroyuki wrote: > On Thu, 14 Jul 2011 17:29:51 +0200 > Michal Hocko 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 > > Acked-by: KAMEZAWA Hiroyuki Thanks! -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic