From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx204.postini.com [74.125.245.204]) by kanga.kvack.org (Postfix) with SMTP id 350746B00A7 for ; Thu, 15 Nov 2012 04:51:08 -0500 (EST) Date: Thu, 15 Nov 2012 10:51:03 +0100 From: Michal Hocko Subject: Re: [RFC 2/5] memcg: rework mem_cgroup_iter to use cgroup iterators Message-ID: <20121115095103.GB11990@dhcp22.suse.cz> References: <1352820639-13521-1-git-send-email-mhocko@suse.cz> <1352820639-13521-3-git-send-email-mhocko@suse.cz> <20121113161442.GA18227@mtj.dyndns.org> <20121114085129.GC17111@dhcp22.suse.cz> <20121114185245.GF21185@mtj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121114185245.GF21185@mtj.dyndns.org> Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, KAMEZAWA Hiroyuki , Johannes Weiner , Ying Han , Glauber Costa On Wed 14-11-12 10:52:45, Tejun Heo wrote: > Hello, Michal. > > On Wed, Nov 14, 2012 at 09:51:29AM +0100, Michal Hocko wrote: > > > reclaim(root); > > > for_each_descendent_pre() > > > reclaim(descendant); > > > > We cannot do for_each_descendent_pre here because we do not iterate > > through the whole hierarchy all the time. Check shrink_zone. > > I'm a bit confused. Why would that make any difference? Shouldn't it > be just able to test the condition and continue? Ohh, I misunderstood your proposal. So what you are suggesting is to put all the logic we have in mem_cgroup_iter inside what you call reclaim here + mem_cgroup_iter_break inside the loop, right? I do not see how this would help us much. mem_cgroup_iter is not the nicest piece of code but it handles quite a complex requirements that we have currently (css reference count, multiple reclaimers racing). So I would rather keep it this way. Further simplifications are welcome of course. Is there any reason why you are not happy about direct using of cgroup_next_descendant_pre? -- 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