Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964820AbbLRQgN (ORCPT ); Fri, 18 Dec 2015 11:36:13 -0500 Received: from gum.cmpxchg.org ([85.214.110.215]:48760 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932676AbbLRQgL (ORCPT ); Fri, 18 Dec 2015 11:36:11 -0500 Date: Fri, 18 Dec 2015 11:35:53 -0500 From: Johannes Weiner To: Michal Hocko Cc: Andrew Morton , Linus Torvalds , Mel Gorman , David Rientjes , Tetsuo Handa , Hillf Danton , KAMEZAWA Hiroyuki , linux-mm@kvack.org, LKML Subject: Re: [PATCH 0/3] OOM detection rework v4 Message-ID: <20151218163553.GC4201@cmpxchg.org> References: <1450203586-10959-1-git-send-email-mhocko@kernel.org> <20151216155844.d1c3a5f35bc98072a80f939e@linux-foundation.org> <20151218131509.GH28443@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151218131509.GH28443@dhcp22.suse.cz> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1314 Lines: 25 On Fri, Dec 18, 2015 at 02:15:09PM +0100, Michal Hocko wrote: > On Wed 16-12-15 15:58:44, Andrew Morton wrote: > > It's hard to say how long declaration of oom should take. Correctness > > comes first. But what is "correct"? oom isn't a binary condition - > > there's a chance that if we keep churning away for another 5 minutes > > we'll be able to satisfy this allocation (but probably not the next > > one). There are tradeoffs between promptness-of-declaring-oom and > > exhaustiveness-in-avoiding-it. > > Yes, this is really hard to tell. What I wanted to achieve here is a > determinism - the same load should give comparable results. It seems > that there is an improvement in this regards. The time to settle is > much more consistent than with the original implementation. +1 Before that we couldn't even really make a meaningful statement about how long we are going to try - "as long as reclaim thinks it can maybe do some more, depending on heuristics". I think the best thing we can strive for with OOM is to make the rules simple and predictable. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/