Hi, The system supposes to have special memory reservation for coredump and other debug info when encountering panic, the size seems configurable. Thanks, Xin
Sent: Saturday, December 17, 2016 at 6:44 AM From: "Tetsuo Handa" <penguin-ker...@i-love.sakura.ne.jp> To: "Nils Holland" <nholl...@tisys.org>, "Michal Hocko" <mho...@kernel.org> Cc: linux-kernel@vger.kernel.org, linux...@kvack.org, "Chris Mason" <c...@fb.com>, "David Sterba" <dste...@suse.cz>, linux-bt...@vger.kernel.org Subject: Re: OOM: Better, but still there on 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. When that happened, I let it run for > another minute or two so that in case it was still logging something > to the trace file, it could continue to do so some time longer. Then I > rebooted with the only thing that still worked, i.e. by means of magic > SysRequest. 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. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html[http://vger.kernel.org/majordomo-info.html]
