From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f47.google.com (mail-wg0-f47.google.com [74.125.82.47]) by kanga.kvack.org (Postfix) with ESMTP id 53C0B6B009A for ; Wed, 8 Oct 2014 10:08:04 -0400 (EDT) Received: by mail-wg0-f47.google.com with SMTP id x13so11705534wgg.30 for ; Wed, 08 Oct 2014 07:08:03 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id iu6si17776009wic.41.2014.10.08.07.08.03 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 08 Oct 2014 07:08:03 -0700 (PDT) From: Michal Hocko Subject: [PATCH 0/3] OOM vs. freezer interaction fixes Date: Wed, 8 Oct 2014 16:07:43 +0200 Message-Id: <1412777266-8251-1-git-send-email-mhocko@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , "\\\"Rafael J. Wysocki\\\"" Cc: Cong Wang , David Rientjes , Tejun Heo , LKML , linux-mm@kvack.org Hi Andrew, Rafael, this has been originally discussed here [1] but didn't lead anywhere AFAICS so I would like to resurrect them. The first and third patch are regression fixes and they are a stable material IMO. The second patch is a simple cleanup. The 1st patch is fixing a regression introduced in 3.3 since when OOM killer is not able to kill any frozen task and live lock as a result. The fix gets us back to the 3.2. As it turned out during the discussion [2] this was still not 100% sufficient and that's why we need the 3rd patch. I was thinking about the proper 1st vs. 3rd patch ordering because the 1st patch basically opens a race window fixed by the later patch. Original patch from Cong Wang has covered this by cgroup_freezing(current) check in should_thaw_current(). But this approach still suffers from OOM vs. PM freezer interaction (OOM killer would still live lock waiting for a PM frozen task this time). So I think the most straight forward way is to address only OOM vs. frozen task interaction in the first patch, mark it for stable 3.3+ and leave the race to a separate follow up patch which is applicable to stable 3.2+ (before a3201227f803 made it inefficient). Switching 1st and 3rd patches would make some sense as well but then it might end up even more confusing because we would be fixing a non-existent issue in upstream first... --- [1] http://marc.info/?l=linux-kernel&m=140986986423092 [2] http://marc.info/?l=linux-kernel&m=141074263721166 -- 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