Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752874Ab0BPGP6 (ORCPT ); Tue, 16 Feb 2010 01:15:58 -0500 Received: from cantor.suse.de ([195.135.220.2]:60189 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752021Ab0BPGP4 (ORCPT ); Tue, 16 Feb 2010 01:15:56 -0500 Date: Tue, 16 Feb 2010 17:15:53 +1100 From: Nick Piggin To: David Rientjes Cc: Andrew Morton , Rik van Riel , KAMEZAWA Hiroyuki , Andrea Arcangeli , Balbir Singh , Lubos Lunak , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [patch -mm 2/9 v2] oom: sacrifice child with highest badness score for parent Message-ID: <20100216061553.GZ5723@laptop> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1895 Lines: 34 On Mon, Feb 15, 2010 at 02:20:03PM -0800, David Rientjes wrote: > 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 > Reviewed-by: KAMEZAWA Hiroyuki > Reviewed-by: Minchan Kim > Reviewed-by: KOSAKI Motohiro > Signed-off-by: David Rientjes Acked-by: Nick Piggin -- 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/