From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936936Ab0COVvA (ORCPT ); Mon, 15 Mar 2010 17:51:00 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:42543 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936926Ab0COVuz (ORCPT ); Mon, 15 Mar 2010 17:50:55 -0400 Date: Mon, 15 Mar 2010 14:50:13 -0700 From: Andrew Morton To: KAMEZAWA Hiroyuki Cc: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "balbir@linux.vnet.ibm.com" , "nishimura@mxp.nes.nec.co.jp" , "kirill@shutemov.name" Subject: Re: [PATCH 1/3] memcg: oom wakeup filter Message-Id: <20100315145013.ee5919fd.akpm@linux-foundation.org> In-Reply-To: <20100312143137.f4cf0a04.kamezawa.hiroyu@jp.fujitsu.com> References: <20100312143137.f4cf0a04.kamezawa.hiroyu@jp.fujitsu.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.9; x86_64-pc-linux-gnu) 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 On Fri, 12 Mar 2010 14:31:37 +0900 KAMEZAWA Hiroyuki wrote: > +static int memcg_oom_wake_function(wait_queue_t *wait, > + unsigned mode, int sync, void *arg) > +{ > + struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg; > + struct oom_wait_info *oom_wait_info; > + > + /* both of oom_wait_info->mem and wake_mem are stable under us */ > + oom_wait_info = container_of(wait, struct oom_wait_info, wait); > + > + if (oom_wait_info->mem == wake_mem) > + goto wakeup; > + /* if no hierarchy, no match */ > + if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy) > + return 0; > + /* check hierarchy */ > + if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) && > + !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) > + return 0; > + > +wakeup: > + return autoremove_wake_function(wait, mode, sync, arg); > +} What are the locking rules for calling css_is_ancestor()?