Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932810AbZIDHj5 (ORCPT ); Fri, 4 Sep 2009 03:39:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932472AbZIDHjz (ORCPT ); Fri, 4 Sep 2009 03:39:55 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:49859 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751585AbZIDHjz (ORCPT ); Fri, 4 Sep 2009 03:39:55 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Fri, 4 Sep 2009 16:37:58 +0900 From: KAMEZAWA Hiroyuki To: Daisuke Nishimura Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "balbir@linux.vnet.ibm.com" , "akpm@linux-foundation.org" Subject: [mmotm][BUGFIX][PATCH] memcg: fix softlimit css refcnt handling. Message-Id: <20090904163758.a5604fee.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090904154050.25873aa5.nishimura@mxp.nes.nec.co.jp> References: <20090902093438.eed47a57.kamezawa.hiroyu@jp.fujitsu.com> <20090902134114.b6f1a04d.kamezawa.hiroyu@jp.fujitsu.com> <20090902182923.c6d98fd6.kamezawa.hiroyu@jp.fujitsu.com> <20090903141727.ccde7e91.nishimura@mxp.nes.nec.co.jp> <20090904131835.ac2b8cc8.kamezawa.hiroyu@jp.fujitsu.com> <20090904141157.4640ec1e.nishimura@mxp.nes.nec.co.jp> <20090904142143.15ffcb53.kamezawa.hiroyu@jp.fujitsu.com> <20090904142654.08dd159f.kamezawa.hiroyu@jp.fujitsu.com> <20090904154050.25873aa5.nishimura@mxp.nes.nec.co.jp> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.5.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2107 Lines: 67 On Fri, 4 Sep 2009 15:40:50 +0900 Daisuke Nishimura wrote: > > Ah, one more question. What memory.usage_in_bytes shows in that case ? > > If not zero, charge/uncharge coalescing is guilty. > > > usage_in_bytes is 0. > I've confirmed by crash command that the mem_cgroup has extra ref counts. > > I'll dig more.. > BTW, do you use softlimit ? I found this but...Hmm == SoftLimit tree 'find next one' loop uses next_mz to remember next one to be visited if reclaimd==0. But css'refcnt handling for next_mz is not enough and it makes css->refcnt leak. Signed-off-by: KAMEZAWA Hiroyuki --- mm/memcontrol.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) Index: mmotm-2.6.31-Aug27/mm/memcontrol.c =================================================================== --- mmotm-2.6.31-Aug27.orig/mm/memcontrol.c +++ mmotm-2.6.31-Aug27/mm/memcontrol.c @@ -2261,6 +2261,8 @@ unsigned long mem_cgroup_soft_limit_recl if (!reclaimed) { do { /* + * Loop until we find yet another one. + * * By the time we get the soft_limit lock * again, someone might have aded the * group back on the RB tree. Iterate to @@ -2271,7 +2273,12 @@ unsigned long mem_cgroup_soft_limit_recl */ next_mz = __mem_cgroup_largest_soft_limit_node(mctz); - } while (next_mz == mz); + if (next_mz == mz) { + css_put(&next_mz->mem->css); + next_mz = NULL; + } else /* next_mz == NULL or other memcg */ + break; + } while (1); } mz->usage_in_excess = res_counter_soft_limit_excess(&mz->mem->res); @@ -2299,6 +2306,8 @@ unsigned long mem_cgroup_soft_limit_recl loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) break; } while (!nr_reclaimed); + if (next_mz) + css_put(&next_mz->mem->css); return nr_reclaimed; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/