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 SMTP id 5D937600429 for ; Mon, 2 Aug 2010 23:12:25 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp ([10.0.50.71]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o733GfUB009814 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Tue, 3 Aug 2010 12:16:42 +0900 Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id C057245DE50 for ; Tue, 3 Aug 2010 12:16:41 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 8C24345DE4F for ; Tue, 3 Aug 2010 12:16:41 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 758101DB804C for ; Tue, 3 Aug 2010 12:16:41 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id BFB601DB804F for ; Tue, 3 Aug 2010 12:16:37 +0900 (JST) Date: Tue, 3 Aug 2010 12:11:46 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [patch -mm 1/2] oom: badness heuristic rewrite Message-Id: <20100803121146.cf35b7ed.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20100730091125.4AC3.A69D9226@jp.fujitsu.com> <20100729183809.ca4ed8be.akpm@linux-foundation.org> <20100730195338.4AF6.A69D9226@jp.fujitsu.com> <20100802134312.c0f48615.akpm@linux-foundation.org> <20100803090058.48c0a0c9.kamezawa.hiroyu@jp.fujitsu.com> <20100803093610.f4d30ca7.kamezawa.hiroyu@jp.fujitsu.com> <20100803100815.11d10519.kamezawa.hiroyu@jp.fujitsu.com> <20100803102423.82415a17.kamezawa.hiroyu@jp.fujitsu.com> <20100803110534.e3e7a697.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: David Rientjes Cc: Andrew Morton , KOSAKI Motohiro , Nick Piggin , Oleg Nesterov , Balbir Singh , linux-mm@kvack.org List-ID: On Mon, 2 Aug 2010 20:05:18 -0700 (PDT) David Rientjes wrote: > On Tue, 3 Aug 2010, KAMEZAWA Hiroyuki wrote: > > > > Sure, a task could be killed with a very low /proc/pid/oom_score, but only > > > if its cpuset is oom, for example, and it has the highest score of all > > > tasks attached to that oom_score. So /proc/pid/oom_score needs to be > > > considered in the context in which the oom occurs: system-wide, cpuset, > > > mempolicy, or memcg. That's unchanged from the old oom killer. > > > > > > > unchanged ? > > > > Oh, I meant the fact that a task with a low oom_score compared to other > system tasks may be killed because a cpuset is oom, for instance, is > unchanged because we only kill tasks that are constrained to that cpuset. > > > Assume 2 proceses A, B which has oom_score_adj of 300 and 0 > > And A uses 200M, B uses 1G of memory under 4G system > > > > Under the system. > > A's socre = (200M *1000)/4G + 300 = 350 > > B's score = (1G * 1000)/4G = 250. > > Right, A is penalized 30% of system memory and its use is ~5%, resulting > in a score of 350, or 35%. B's use is 25%. > > > In the cpuset, it has 2G of memory. > > A's score = (200M * 1000)/2G + 300 = 400 > > B's socre = (1G * 1000)/2G = 500 > > > > This priority-inversion don't happen in current system. > > > > Yes, but this is what oom_score_adj is intended to do: an oom_score_adj of > 300 means task A should be penalized 30% of available memory. A positive > oom_score_adj typically means "all other competing tasks should be allowed > 30% more memory, cumulatively, compared to this task." Task A uses ~10% > of available memory and task B uses 50% of available memory. That's a 40% > difference, which is greater than task A's penalization of 30%, so B is > killed. > This will confuse LXC(Linux Container) guys. oom_score is unusable anymore. Thanks, -Kame -- 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