Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752042Ab0BWGK2 (ORCPT ); Tue, 23 Feb 2010 01:10:28 -0500 Received: from e23smtp02.au.ibm.com ([202.81.31.144]:47170 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751648Ab0BWGKZ (ORCPT ); Tue, 23 Feb 2010 01:10:25 -0500 Date: Tue, 23 Feb 2010 11:40:20 +0530 From: Balbir Singh To: KAMEZAWA Hiroyuki Cc: "nishimura@mxp.nes.nec.co.jp" , rientjes@google.com, "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: Re: [RFC][PATCH] memcg: page fault oom improvement Message-ID: <20100223061020.GH3063@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20100223120315.0da4d792.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20100223120315.0da4d792.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2134 Lines: 50 * KAMEZAWA Hiroyuki [2010-02-23 12:03:15]: > Nishimura-san, could you review and test your extreme test case with this ? > > == > From: KAMEZAWA Hiroyuki > > Now, because of page_fault_oom_kill, returning VM_FAULT_OOM means > random oom-killer should be called. Considering memcg, it handles > OOM-kill in its own logic, there was a problem as "oom-killer called > twice" problem. > > By commit a636b327f731143ccc544b966cfd8de6cb6d72c6, I added a check > in pagefault_oom_killer shouldn't kill some (random) task if > memcg's oom-killer already killed anyone. > That was done by comapring current jiffies and last oom jiffies of memcg. > > I thought that easy fix was enough, but Nishimura could write a test case > where checking jiffies is not enough. So, my fix was not enough. > This is a fix of above commit. > > This new one does this. > * memcg's try_charge() never returns -ENOMEM if oom-killer is allowed. > * If someone is calling oom-killer, wait for it in try_charge(). > * If TIF_MEMDIE is set as a result of try_charge(), return 0 and > allow process to make progress (and die.) > * removed hook in pagefault_out_of_memory. > > By this, pagefult_out_of_memory will be never called if memcg's oom-killer > is called and scattered codes are now in memcg's charge logic again. > > TODO: > If __GFP_WAIT is not specified in gfp_mask flag, VM_FAULT_OOM will return > anyway. We need to investigate it whether there is a case. > > Cc: David Rientjes > Cc: Balbir Singh > Cc: Daisuke Nishimura > Signed-off-by: KAMEZAWA Hiroyuki I've not reviewed David's latest OOM killer changes. Are these changes based on top of what is going to come in with David's proposal? -- Three Cheers, Balbir -- 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/