From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 0AD665F0001 for ; Tue, 3 Feb 2009 00:35:58 -0500 (EST) Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by e28smtp05.in.ibm.com (8.13.1/8.13.1) with ESMTP id n135ZrWH017561 for ; Tue, 3 Feb 2009 11:05:53 +0530 Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay02.in.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id n135XZns4444180 for ; Tue, 3 Feb 2009 11:03:35 +0530 Received: from d28av02.in.ibm.com (loopback [127.0.0.1]) by d28av02.in.ibm.com (8.13.1/8.13.3) with ESMTP id n135ZqfJ012564 for ; Tue, 3 Feb 2009 16:35:53 +1100 Date: Tue, 3 Feb 2009 11:05:51 +0530 From: Balbir Singh Subject: Re: [-mm patch] Show memcg information during OOM Message-ID: <20090203053551.GP918@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20090202125240.GA918@balbir.in.ibm.com> <20090202140849.GB918@balbir.in.ibm.com> <49879DE5.8030505@cn.fujitsu.com> <20090203044143.GM918@balbir.in.ibm.com> <4987D512.90001@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <4987D512.90001@cn.fujitsu.com> Sender: owner-linux-mm@kvack.org To: Li Zefan Cc: David Rientjes , KAMEZAWA Hiroyuki , Andrew Morton , "linux-kernel@vger.kernel.org" , "nishimura@mxp.nes.nec.co.jp" , "linux-mm@kvack.org" List-ID: * Li Zefan [2009-02-03 13:24:34]: > David Rientjes wrote: > > On Tue, 3 Feb 2009, Balbir Singh wrote: > > > >>>> diff --git a/mm/oom_kill.c b/mm/oom_kill.c > >>>> index d3b9bac..b8e53ae 100644 > >>>> --- a/mm/oom_kill.c > >>>> +++ b/mm/oom_kill.c > >>>> @@ -392,6 +392,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, > >>>> current->comm, gfp_mask, order, current->oomkilladj); > >>>> task_lock(current); > >>>> cpuset_print_task_mems_allowed(current); > >>>> + mem_cgroup_print_mem_info(mem); > >>> I think this can be put outside the task lock. The lock is used to call task_cs() safely in > >>> cpuset_print_task_mems_allowed(). > >>> > >> Thanks, I'll work on that in the next version. > >> > > > > I was also wondering about this and assumed that it was necessary to > > prevent the cgroup from disappearing during the oom. If task_lock() isn't > > held, is the memcg->css.cgroup->dentry->d_name.name dereference always > > safe without rcu? > > > > The cgroup won't disappear, since mem_cgroup_out_of_memory() is called with memcg's css refcnt > increased. :) > And this as well, yes! -- Balbir -- 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