From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752446AbZGaKtI (ORCPT ); Fri, 31 Jul 2009 06:49:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752417AbZGaKtH (ORCPT ); Fri, 31 Jul 2009 06:49:07 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:36809 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752414AbZGaKtG (ORCPT ); Fri, 31 Jul 2009 06:49:06 -0400 Message-ID: <7f54310137837631f2526d4e335287fc.squirrel@webmail-b.css.fujitsu.com> In-Reply-To: References: <20090730180029.c4edcc09.kamezawa.hiroyu@jp.fujitsu.com> <20090730190216.5aae685a.kamezawa.hiroyu@jp.fujitsu.com> <20090731093305.50bcc58d.kamezawa.hiroyu@jp.fujitsu.com> Date: Fri, 31 Jul 2009 19:49:02 +0900 (JST) Subject: Re: [patch -mm v2] mm: introduce oom_adj_child From: "KAMEZAWA Hiroyuki" To: "David Rientjes" Cc: "KAMEZAWA Hiroyuki" , "Andrew Morton" , "Rik van Riel" , "Paul Menage" , "KOSAKI Motohiro" , linux-kernel@vger.kernel.org, linux-mm@kvack.org User-Agent: SquirrelMail/1.4.16 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-2022-jp Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org David Rientjes wrote: > On Fri, 31 Jul 2009, KAMEZAWA Hiroyuki wrote: > >> > > Simply, reset_oom_adj_at_new_mm_context or some. >> > > >> > >> > I think it's preferred to keep the name relatively short which is an >> > unfortuante requirement in this case. I also prefer to start the name >> > with "oom_adj" so it appears alongside /proc/pid/oom_adj when listed >> > alphabetically. >> > >> But misleading name is bad. >> > > Can you help think of any names that start with oom_adj_* and are > relatively short? I'd happily ack it. > There have been traditional name "effective" as uid and euid. then, per thread oom_adj as oom_adj per proc oom_adj as effective_oom_adj is an natural way as Unix, I think. >> Why don't you think select_bad_process()-> oom_kill_task() >> implementation is bad ? > > It livelocks if a thread is chosen and passed to oom_kill_task() while > another per-thread oom_adj value is OOM_DISABLE for a thread sharing the > same memory. > I say "why don't modify buggy selection logic?" Why we have to scan all threads ? As fs/proc/readdir does, you can scan only "process group leader". per-thread scan itself is buggy because now we have per-process effective-oom-adj. >> IMHO, it's bad manner to fix an os-implementation problem by adding >> _new_ user >> interface which is hard to understand. >> > > How else do you propose the oom killer use oom_adj values on a per-thread > basis without considering other threads sharing the same memory? As I wrote. per-process(signal struct) or per-thread oom_adj and add mm->effecitve_oom_adj task scanning isn't necessary to do per-thread scan and you can scan only process-group-leader. What's bad ? If oom_score is problem, plz fix it to show effective_oom_score. If you can wait until the end of August, plz wait. I'll do some. Thanks, -Kame