From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754856AbZHCMM5 (ORCPT ); Mon, 3 Aug 2009 08:12:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754742AbZHCMM4 (ORCPT ); Mon, 3 Aug 2009 08:12:56 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:35946 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754729AbZHCMM4 (ORCPT ); Mon, 3 Aug 2009 08:12:56 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: KOSAKI Motohiro Subject: Re: [patch -mm v2] mm: introduce oom_adj_child Cc: kosaki.motohiro@jp.fujitsu.com, David Rientjes , Andrew Morton , Rik van Riel , Paul Menage , linux-kernel@vger.kernel.org, linux-mm@kvack.org In-Reply-To: <20090803200639.CC1D.A69D9226@jp.fujitsu.com> References: <20090803200639.CC1D.A69D9226@jp.fujitsu.com> Message-Id: <20090803211112.CC23.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Mon, 3 Aug 2009 21:12:53 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org One mistake. > > > And, May I explay why I think your oom_adj_child is wrong idea? > > > The fact is: new feature introducing never fix regression. yes, some > > > application use new interface and disappear the problem. but other > > > application still hit the problem. that's not correct development style > > > in kernel. > > > > > > > So you're proposing that we forever allow /proc/pid/oom_score to be > > completely wrong for pid without any knowledge to userspace? That we > > falsely advertise what it represents and allow userspace to believe that > > changing oom_adj for a thread sharing memory with other threads actually > > changes how the oom killer selects tasks? > > No. perhaps no doublly. > > 1) In my patch, oom_score is also per-process value. all thread have the same > oom_score. > It's clear meaning. it's wrong explanation. oom_score is calculated from the same oom_adj. but it have each different oom_score. sorry my confused. > 2) In almost case, oom_score display collect value because oom_adj is per-process > value too. > Yes, there is one exception. vfork() and change oom_adj'ed process might display > wrong value. but I don't think it is serious problem because vfork() process call > exec() soon. > Administrator never recognize this difference. > > > Please. > > David, I hope you join to fix this regression. I can't believe we > can't fix this issue honestly. > > >