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 804E36B0012 for ; Mon, 23 May 2011 18:28:35 -0400 (EDT) Received: from kpbe18.cbf.corp.google.com (kpbe18.cbf.corp.google.com [172.25.105.82]) by smtp-out.google.com with ESMTP id p4NMSYwU018600 for ; Mon, 23 May 2011 15:28:34 -0700 Received: from pvg13 (pvg13.prod.google.com [10.241.210.141]) by kpbe18.cbf.corp.google.com with ESMTP id p4NMSWNi014644 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Mon, 23 May 2011 15:28:32 -0700 Received: by pvg13 with SMTP id 13so3215671pvg.26 for ; Mon, 23 May 2011 15:28:32 -0700 (PDT) Date: Mon, 23 May 2011 15:28:29 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH 3/5] oom: oom-killer don't use proportion of system-ram internally In-Reply-To: <4DD6204D.5020109@jp.fujitsu.com> Message-ID: References: <4DD61F80.1020505@jp.fujitsu.com> <4DD6204D.5020109@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, caiqian@redhat.com, hughd@google.com, kamezawa.hiroyu@jp.fujitsu.com, minchan.kim@gmail.com, oleg@redhat.com On Fri, 20 May 2011, KOSAKI Motohiro wrote: > CAI Qian reported his kernel did hang-up if he ran fork intensive > workload and then invoke oom-killer. > > The problem is, current oom calculation uses 0-1000 normalized value > (The unit is a permillage of system-ram). Its low precision make > a lot of same oom score. IOW, in his case, all processes have smaller > oom score than 1 and internal calculation round it to 1. > > Thus oom-killer kill ineligible process. This regression is caused by > commit a63d83f427 (oom: badness heuristic rewrite). > > The solution is, the internal calculation just use number of pages > instead of permillage of system-ram. And convert it to permillage > value at displaying time. > > This patch doesn't change any ABI (included /proc//oom_score_adj) > even though current logic has a lot of my dislike thing. > Same response as when you initially proposed this patch: http://marc.info/?l=linux-kernel&m=130507086613317 -- you never replied to that. The changelog doesn't accurately represent CAI Qian's problem; the issue is that root processes are given too large of a bonus in comparison to other threads that are using at most 1.9% of available memory. That can be fixed, as I suggested by giving 1% bonus per 10% of memory used so that the process would have to be using 10% before it even receives a bonus. I already suggested an alternative patch to CAI Qian to greatly increase the granularity of the oom score from a range of 0-1000 to 0-10000 to differentiate between tasks within 0.01% of available memory (16MB on CAI Qian's 16GB system). I'll propose this officially in a separate email. This patch also includes undocumented changes such as changing the bonus given to root processes. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org