From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qa0-f51.google.com (mail-qa0-f51.google.com [209.85.216.51]) by kanga.kvack.org (Postfix) with ESMTP id 42D4A6B00A8 for ; Tue, 4 Nov 2014 14:27:10 -0500 (EST) Received: by mail-qa0-f51.google.com with SMTP id f12so10171150qad.38 for ; Tue, 04 Nov 2014 11:27:10 -0800 (PST) Received: from mail-qc0-x22c.google.com (mail-qc0-x22c.google.com. [2607:f8b0:400d:c01::22c]) by mx.google.com with ESMTPS id r16si2293207qam.57.2014.11.04.11.27.08 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 04 Nov 2014 11:27:09 -0800 (PST) Received: by mail-qc0-f172.google.com with SMTP id i17so11564275qcy.31 for ; Tue, 04 Nov 2014 11:27:08 -0800 (PST) Date: Tue, 4 Nov 2014 14:27:05 -0500 From: Tejun Heo Subject: Re: [PATCH 3/4] OOM, PM: OOM killed task shouldn't escape PM suspend Message-ID: <20141104192705.GA22163@htj.dyndns.org> References: <1413876435-11720-1-git-send-email-mhocko@suse.cz> <2156351.pWp6MNRoWm@vostro.rjw.lan> <20141021141159.GE9415@dhcp22.suse.cz> <4766859.KSKPTm3b0x@vostro.rjw.lan> <20141021142939.GG9415@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141021142939.GG9415@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: "Rafael J. Wysocki" , Andrew Morton , Cong Wang , David Rientjes , Oleg Nesterov , LKML , linux-mm@kvack.org, Linux PM list Hello, Sorry about the delay. On Tue, Oct 21, 2014 at 04:29:39PM +0200, Michal Hocko wrote: > Reduce the race window by checking all tasks after OOM killer has been Ugh... this is never a good direction to take. It often just ends up making bugs harder to reproduce and track down. > disabled. This is still not race free completely unfortunately because > oom_killer_disable cannot stop an already ongoing OOM killer so a task > might still wake up from the fridge and get killed without > freeze_processes noticing. Full synchronization of OOM and freezer is, > however, too heavy weight for this highly unlikely case. Both oom killing and PM freezing are exremely rare events and I have difficult time why their exclusion would be heavy weight. Care to elaborate? Overall, this is a lot of complexity for something which doesn't really fix the problem and the comments while referring to the race don't mention that the implemented "fix" is broken, which is pretty bad as it gives readers of the code a false sense of security and another hurdle to overcome in actually tracking down what went wrong if this thing ever shows up as an actual breakage. I'd strongly recommend implementing something which is actually correct. Thanks. -- tejun -- 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