From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758745Ab2C2AUi (ORCPT ); Wed, 28 Mar 2012 20:20:38 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:39455 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751941Ab2C2AUa (ORCPT ); Wed, 28 Mar 2012 20:20:30 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Message-ID: <4F73AA5F.5050604@jp.fujitsu.com> Date: Thu, 29 Mar 2012 09:18:39 +0900 From: KAMEZAWA Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.0; rv:11.0) Gecko/20120312 Thunderbird/11.0 MIME-Version: 1.0 To: "Aneesh Kumar K.V" CC: Michal Hocko , linux-mm@kvack.org, mgorman@suse.de, dhillf@gmail.com, aarcange@redhat.com, akpm@linux-foundation.org, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH -V4 04/10] memcg: Add HugeTLB extension References: <1331919570-2264-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1331919570-2264-5-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20120328134020.GG20949@tiehlicka.suse.cz>User-Agent: Notmuch/0.11.1+346~g13d19c3 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) <87y5qk1vat.fsf@skywalker.in.ibm.com> In-Reply-To: <87y5qk1vat.fsf@skywalker.in.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2012/03/29 2:37), Aneesh Kumar K.V wrote: > Michal Hocko writes: > >> On Fri 16-03-12 23:09:24, Aneesh Kumar K.V wrote: >> [...] >>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >>> index 6728a7a..4b36c5e 100644 >>> --- a/mm/memcontrol.c >>> +++ b/mm/memcontrol.c >> [...] >>> @@ -4887,6 +5013,7 @@ err_cleanup: >>> static struct cgroup_subsys_state * __ref >>> mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) >>> { >>> + int idx; >>> struct mem_cgroup *memcg, *parent; >>> long error = -ENOMEM; >>> int node; >>> @@ -4929,9 +5056,14 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) >>> * mem_cgroup(see mem_cgroup_put). >>> */ >>> mem_cgroup_get(parent); >>> + for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) >>> + res_counter_init(&memcg->hugepage[idx], >>> + &parent->hugepage[idx]); >> >> Hmm, I do not think we want to make groups deeper in the hierarchy >> unlimited as we cannot reclaim. Shouldn't we copy the limit from the parent? >> Still not ideal but slightly more expected behavior IMO. > > But we should be limiting the child group based on parent's limit only > when hierarchy is set right ? > >> >> The hierarchy setups are still interesting and the limitations should be >> described in the documentation... >> > > It should behave similar to memcg. ie, if hierarchy is set, then we limit > using MIN(parent's limit, child's limit). May be I am missing some of > the details of memcg use_hierarchy config. My goal was to keep it > similar to memcg. Can you explain why do you think the patch would > make it any different ? > Maybe this is a different story but.... Tejun(Cgroup Maintainer) asked us to remove 'use_hierarchy' settings because most of other cgroups are hierarchical(*). I answered that improvement in res_counter latency is required. And now, we have some idea to improve res_counter. (I'd like to try this after page_cgroup diet series..) If we change and drop use_hierarchy, the usage similar to current use_hierarchy=0 will be.. /cgroup/memory/ = unlimited level1 = unlimited level2 = unlimited level3 = limit To do this, after improvement of res_counter, we entry use_hierarchy into feature-removal-list and wait for 2 versions..So, this will not affect your developments, anyway. Thanks, -Kame (*) AFAIK, blkio cgroup needs tons of work to be hierarchical...