From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx189.postini.com [74.125.245.189]) by kanga.kvack.org (Postfix) with SMTP id D5DCC6B0032 for ; Fri, 17 May 2013 03:50:22 -0400 (EDT) Date: Fri, 17 May 2013 09:50:19 +0200 From: Michal Hocko Subject: Re: [patch v3 -mm 3/3] vmscan, memcg: Do softlimit reclaim also for targeted reclaim Message-ID: <20130517075019.GF25158@dhcp22.suse.cz> References: <1368431172-6844-1-git-send-email-mhocko@suse.cz> <1368431172-6844-4-git-send-email-mhocko@suse.cz> <51934A62.2030606@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51934A62.2030606@parallels.com> Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: Andrew Morton , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Johannes Weiner , KAMEZAWA Hiroyuki , Ying Han , Hugh Dickins , Michel Lespinasse , Greg Thelen , Tejun Heo , Balbir Singh On Wed 15-05-13 12:42:10, Glauber Costa wrote: > On 05/13/2013 11:46 AM, Michal Hocko wrote: > > Soft reclaim has been done only for the global reclaim (both background > > and direct). Since "memcg: integrate soft reclaim tighter with zone > > shrinking code" there is no reason for this limitation anymore as the > > soft limit reclaim doesn't use any special code paths and it is a > > part of the zone shrinking code which is used by both global and > > targeted reclaims. > > > > From semantic point of view it is even natural to consider soft limit > > before touching all groups in the hierarchy tree which is touching the > > hard limit because soft limit tells us where to push back when there is > > a memory pressure. It is not important whether the pressure comes from > > the limit or imbalanced zones. > > > > This patch simply enables soft reclaim unconditionally in > > mem_cgroup_should_soft_reclaim so it is enabled for both global and > > targeted reclaim paths. mem_cgroup_soft_reclaim_eligible needs to learn > > about the root of the reclaim to know where to stop checking soft limit > > state of parents up the hierarchy. > > Say we have > > A (over soft limit) > > \ > > B (below s.l., hit the hard limit) > > / \ > > C D (below s.l.) > > > > B is the source of the outside memory pressure now for D but we > > shouldn't soft reclaim it because it is behaving well under B subtree > > and we can still reclaim from C (pressumably it is over the limit). > > mem_cgroup_soft_reclaim_eligible should therefore stop climbing up the > > hierarchy at B (root of the memory pressure). > > > > Changes since v1 > > - add sc->target_mem_cgroup handling into mem_cgroup_soft_reclaim_eligible > > > > Signed-off-by: Michal Hocko > > --- > > Reviewed-by: Glauber Costa Thanks for the review Glauber! -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org