From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262700AbVAKKvN (ORCPT ); Tue, 11 Jan 2005 05:51:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262702AbVAKKvM (ORCPT ); Tue, 11 Jan 2005 05:51:12 -0500 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:21897 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S262700AbVAKKuq (ORCPT ); Tue, 11 Jan 2005 05:50:46 -0500 Date: Tue, 11 Jan 2005 05:47:22 -0200 From: Marcelo Tosatti To: Mauricio Lin Cc: Edjard Souza Mota , linux-kernel@vger.kernel.org Subject: Re: User space out of memory approach Message-ID: <20050111074722.GC18796@logos.cnet> References: <3f250c71050110134337c08ef0@mail.gmail.com> <20050110192012.GA18531@logos.cnet> <4d6522b9050110144017d0c075@mail.gmail.com> <20050110200514.GA18796@logos.cnet> <3f250c71050110152421e83e04@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3f250c71050110152421e83e04@mail.gmail.com> User-Agent: Mutt/1.5.5.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 10, 2005 at 07:24:35PM -0400, Mauricio Lin wrote: > On Mon, 10 Jan 2005 18:05:14 -0200, Marcelo Tosatti > wrote: > > On Tue, Jan 11, 2005 at 12:40:24AM +0200, Edjard Souza Mota wrote: > > > Hi, > > > > > > I guess it the idea was not fully and well explained. It is not the OOM Killer > > > itself that was moved to user space but rather its ranking algorithm. > > > Ranking is not an specific functionality of kernel space. Kernel only need > > > to know which process whould be killed. > > > > > > In that sense the approach is different and might be worth testing, mainly for > > > cases where we want to allow better policies of ranking. For example, an > > > embedded device with few resources and important different running applications: > > > whic one is the best? To my understanding the current ranking policy > > > does not necessarily chooses the best one to be killed. > > > > Sorry, I misunderstood. Should have read the code before shouting. > > > > The feature is interesting - several similar patches have been around with similar > > functionality (people who need usually write their own, I've seen a few), but none > > has ever been merged, even though it is an important requirement for many users. > > > > This is simple, an ordered list of candidate PIDs. IMO something similar to this > > should be merged. Andrew ? > > > > Few comments about the code: > > > > retry: > > - p = select_bad_process(); > > + printk(KERN_DEBUG "A good walker leaves no tracks.\n"); > > + p = select_process(); > > > > You want to fallback to select_bad_process() if no candidate has been selected at > > select_process(). > The idea is turn off the select_bad_process() and the new > select_process() will get the list of pids to be killed from > /proc/oom. But the ranking algorithms is the same, I mean is the Rik > van Riel algorithm. Do you think it is worthwhile to maintain the > select_bad_process (kernel space algorithm) if we have the > select_process() function? Yes, if select_process() fails (in case no process is on the candidate list), i fallbacking to select_bad_process() is important I think. > > > > You also want to move "oom" to /proc/sys/vm/. > > This can be possible. Do you think that it is a good place to move the oom? Yep.