From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f49.google.com (mail-wm0-f49.google.com [74.125.82.49]) by kanga.kvack.org (Postfix) with ESMTP id A75256B0005 for ; Fri, 18 Dec 2015 11:36:10 -0500 (EST) Received: by mail-wm0-f49.google.com with SMTP id p187so71872626wmp.0 for ; Fri, 18 Dec 2015 08:36:10 -0800 (PST) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id f187si13302208wmd.4.2015.12.18.08.36.09 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 Dec 2015 08:36:09 -0800 (PST) Date: Fri, 18 Dec 2015 11:35:53 -0500 From: Johannes Weiner 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> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , Linus Torvalds , Mel Gorman , David Rientjes , Tetsuo Handa , Hillf Danton , KAMEZAWA Hiroyuki , linux-mm@kvack.org, LKML 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, 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