Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757250AbcLQRLW (ORCPT ); Sat, 17 Dec 2016 12:11:22 -0500 Received: from celine.tisys.org ([85.25.117.166]:40818 "EHLO celine.tisys.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751962AbcLQRLV (ORCPT ); Sat, 17 Dec 2016 12:11:21 -0500 Date: Sat, 17 Dec 2016 18:11:13 +0100 From: Nils Holland To: Tetsuo Handa Cc: Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Chris Mason , David Sterba , linux-btrfs@vger.kernel.org Subject: Re: OOM: Better, but still there on Message-ID: <20161217171112.GA7327@boerne.fritz.box> References: <20161216073941.GA26976@dhcp22.suse.cz> <20161216155808.12809-1-mhocko@kernel.org> <20161216184655.GA5664@boerne.fritz.box> <20161217000203.GC23392@dhcp22.suse.cz> <20161217125950.GA3321@boerne.fritz.box> <862a1ada-17f1-9cff-c89b-46c47432e89f@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <862a1ada-17f1-9cff-c89b-46c47432e89f@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1574 Lines: 35 On Sat, Dec 17, 2016 at 11:44:45PM +0900, Tetsuo Handa wrote: > On 2016/12/17 21:59, Nils Holland wrote: > > On Sat, Dec 17, 2016 at 01:02:03AM +0100, Michal Hocko wrote: > >> mount -t tracefs none /debug/trace > >> echo 1 > /debug/trace/events/vmscan/enable > >> cat /debug/trace/trace_pipe > trace.log > >> > >> should help > >> [...] > > > > No problem! I enabled writing the trace data to a file and then tried > > to trigger another OOM situation. That worked, this time without a > > complete kernel panic, but with only my processes being killed and the > > system becoming unresponsive. > > [...] > > Under OOM situation, writing to a file on disk unlikely works. Maybe > logging via network ( "cat /debug/trace/trace_pipe > /dev/udp/$ip/$port" > if your are using bash) works better. (I wish we can do it from kernel > so that /bin/cat is not disturbed by delays due to page fault.) > > If you can configure netconsole for logging OOM killer messages and > UDP socket for logging trace_pipe messages, udplogger at > https://osdn.net/projects/akari/scm/svn/tree/head/branches/udplogger/ > might fit for logging both output with timestamp into a single file. Thanks for the hint, sounds very sane! I'll try to go that route for the next log / trace I produce. Of course, if Michal says that the trace file I've already posted, and which has been logged to file, is useless and would have been better if I had instead logged to a different machine via the network, I could also repeat the current experiment and produce a new file at any time. :-) Greetings Nils