From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f46.google.com (mail-pa0-f46.google.com [209.85.220.46]) by kanga.kvack.org (Postfix) with ESMTP id D75196B0253 for ; Wed, 7 Oct 2015 06:43:18 -0400 (EDT) Received: by pacfv12 with SMTP id fv12so18501397pac.2 for ; Wed, 07 Oct 2015 03:43:18 -0700 (PDT) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [2001:e42:101:1:202:181:97:72]) by mx.google.com with ESMTPS id fy5si56830783pbb.14.2015.10.07.03.43.17 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 07 Oct 2015 03:43:18 -0700 (PDT) Subject: Re: can't oom-kill zap the victim's memory? From: Tetsuo Handa References: <201509290118.BCJ43256.tSFFFMOLHVOJOQ@I-love.SAKURA.ne.jp> <20151002123639.GA13914@dhcp22.suse.cz> <20151005144404.GD7023@dhcp22.suse.cz> <5614AAC0.60002@suse.cz> In-Reply-To: <5614AAC0.60002@suse.cz> Message-Id: <201510071943.DCJ01080.JOFOFFOtLSMQHV@I-love.SAKURA.ne.jp> Date: Wed, 7 Oct 2015 19:43:08 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org List-ID: To: vbabka@suse.cz Cc: mhocko@kernel.org, torvalds@linux-foundation.org, rientjes@google.com, oleg@redhat.com, kwalker@redhat.com, cl@linux.com, akpm@linux-foundation.org, hannes@cmpxchg.org, vdavydov@parallels.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, skozina@redhat.com Vlastimil Babka wrote: > On 5.10.2015 16:44, Michal Hocko wrote: > > So I can see basically only few ways out of this deadlock situation. > > Either we face the reality and allow small allocations (withtout > > __GFP_NOFAIL) to fail after all attempts to reclaim memory have failed > > (so after even OOM killer hasn't made any progress). > > Note that small allocations already *can* fail if they are done in the context > of a task selected as OOM victim (i.e. TIF_MEMDIE). And yeah I've seen a case > when they failed in a code that "handled" the allocation failure with a > BUG_ON(!page). > Did You hit a race described below? http://lkml.kernel.org/r/201508272249.HDH81838.FtQOLMFFOVSJOH@I-love.SAKURA.ne.jp Where was the BUG_ON(!page) ? Maybe it is a candidate for adding __GFP_NOFAIL. -- 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