From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id B39C56B0047 for ; Mon, 1 Mar 2010 23:54:23 -0500 (EST) Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by e28smtp01.in.ibm.com (8.14.3/8.13.1) with ESMTP id o224sHXp001622 for ; Tue, 2 Mar 2010 10:24:17 +0530 Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o224sGK62261194 for ; Tue, 2 Mar 2010 10:24:17 +0530 Received: from d28av01.in.ibm.com (loopback [127.0.0.1]) by d28av01.in.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o224sGiZ004172 for ; Tue, 2 Mar 2010 10:24:16 +0530 Date: Tue, 2 Mar 2010 10:24:13 +0530 From: Balbir Singh Subject: Re: [patch -mm v2 02/10] oom: sacrifice child with highest badness score for parent Message-ID: <20100302045413.GB3212@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: David Rientjes Cc: Andrew Morton , Rik van Riel , Nick Piggin , KAMEZAWA Hiroyuki , KOSAKI Motohiro , linux-mm@kvack.org List-ID: * David Rientjes [2010-02-26 15:53:05]: > When a task is chosen for oom kill, the oom killer first attempts to > sacrifice a child not sharing its parent's memory instead. > Unfortunately, this often kills in a seemingly random fashion based on > the ordering of the selected task's child list. Additionally, it is not > guaranteed at all to free a large amount of memory that we need to > prevent additional oom killing in the very near future. > > Instead, we now only attempt to sacrifice the worst child not sharing its > parent's memory, if one exists. The worst child is indicated with the > highest badness() score. This serves two advantages: we kill a > memory-hogging task more often, and we allow the configurable > /proc/pid/oom_adj value to be considered as a factor in which child to > kill. > > Reviewers may observe that the previous implementation would iterate > through the children and attempt to kill each until one was successful > and then the parent if none were found while the new code simply kills > the most memory-hogging task or the parent. Note that the only time > oom_kill_task() fails, however, is when a child does not have an mm or > has a /proc/pid/oom_adj of OOM_DISABLE. badness() returns 0 for both > cases, so the final oom_kill_task() will always succeed. > > Acked-by: Rik van Riel > Acked-by: Nick Piggin > Reviewed-by: KAMEZAWA Hiroyuki > Reviewed-by: Minchan Kim > Reviewed-by: KOSAKI Motohiro > Signed-off-by: David Rientjes You've got too many of these already, here goes Acked-by: Balbir Singh -- Three Cheers, 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