From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757935Ab2ARP1N (ORCPT ); Wed, 18 Jan 2012 10:27:13 -0500 Received: from cantor2.suse.de ([195.135.220.15]:37428 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757891Ab2ARP1K (ORCPT ); Wed, 18 Jan 2012 10:27:10 -0500 Date: Wed, 18 Jan 2012 16:27:08 +0100 From: Michal Hocko To: Sha Cc: Johannes Weiner , Ying Han , Andrew Morton , KAMEZAWA Hiroyuki , Balbir Singh , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [patch 2/2] mm: memcg: hierarchical soft limit reclaim Message-ID: <20120118152708.GG31112@tiehlicka.suse.cz> References: <1326207772-16762-3-git-send-email-hannes@cmpxchg.org> <20120112085904.GG24386@cmpxchg.org> <20120113224424.GC1653@cmpxchg.org> <4F158418.2090509@gmail.com> <20120117145348.GA3144@cmpxchg.org> <20120118092509.GI24386@cmpxchg.org> <4F16AC27.1080906@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F16AC27.1080906@gmail.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 18-01-12 19:25:27, Sha wrote: [...] > Er... I'm even more confused: mem_cgroup_soft_limit_reclaim indeed > choses the biggest soft-limit excessor first, but in the succeeding reclaim > mem_cgroup_hierarchical_reclaim just selects a child cgroup by css_id mem_cgroup_soft_limit_reclaim picks up the hierarchy root (most excessing one) and mem_cgroup_hierarchical_reclaim reclaims from that subtree). It doesn't care who exceeds the soft limit under that hierarchy it just tries to push the root under its limit as much as it can. This is what Johannes tried to explain in the other email in the thred. > which has nothing to do with soft limit (see mem_cgroup_select_victim). > IMHO, it's not a genuine hierarchical reclaim. It is hierarchical because it iterates over hierarchy it is not and never was recursively soft-hierarchical... -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic