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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>