From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f199.google.com (mail-wj0-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id 0A3D46B0069 for ; Fri, 25 Nov 2016 04:00:26 -0500 (EST) Received: by mail-wj0-f199.google.com with SMTP id o2so2008694wje.5 for ; Fri, 25 Nov 2016 01:00:25 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id mc8si41294688wjb.284.2016.11.25.01.00.24 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 25 Nov 2016 01:00:24 -0800 (PST) Date: Fri, 25 Nov 2016 10:00:22 +0100 From: Michal Hocko Subject: Re: Softlockup during memory allocation Message-ID: <20161125090022.GA24353@dhcp22.suse.cz> References: <20161121053154.GA29816@dhcp22.suse.cz> <20161122143056.GB6831@dhcp22.suse.cz> <6c33f44b-327c-d943-73da-5935136a83c9@kyup.com> <20161122170239.GH6831@dhcp22.suse.cz> <20161123074947.GE2864@dhcp22.suse.cz> <20161124121209.GE20668@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Nikolay Borisov Cc: Linux MM On Thu 24-11-16 15:09:38, Nikolay Borisov wrote: [...] > I just checked all the zones for both nodes (the machines have 2 NUMA > nodes) so essentially there are no reclaimable pages - all are > anonymous. So the pertinent question is why process are sleeping in > reclamation path when there are no pages to free. I also observed the > same behavior on a different node, this time the priority was 0 and the > code hasn't resorted to OOM. This seems all too strange.. >>From my experience we usually hit the memcg OOM quickly if there are no reclaimable pages. I do not remember anything big changed recently in that area. Could you enable mm_vmscan_memcg_isolate, mm_vmscan_memcg_reclaim__{begin,end} and mm_vmscan_lru_shrink_inactive tracepoints to see what is going on during the reclaim? I suspect we will see some minor reclaim activity there which will basically "livelock" the oom from happening but let's see. -- Michal Hocko SUSE Labs -- 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