On Fri 08-01-16 22:14:54, Tetsuo Handa wrote: > Michal Hocko wrote: > > On Thu 07-01-16 11:28:15, Johannes Weiner wrote: > > > On Tue, Dec 29, 2015 at 10:58:22PM +0900, Tetsuo Handa wrote: > > > > >From 8bb9e36891a803e82c589ef78077838026ce0f7d Mon Sep 17 00:00:00 2001 > > > > From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> > > > > Date: Tue, 29 Dec 2015 22:20:58 +0900 > > > > Subject: [PATCH] mm,oom: Exclude TIF_MEMDIE processes from candidates. > > > > > > > > The OOM reaper kernel thread can reclaim OOM victim's memory before the victim > > > > terminates. But since oom_kill_process() tries to kill children of the memory > > > > hog process first, the OOM reaper can not reclaim enough memory for terminating > > > > the victim if the victim is consuming little memory. The result is OOM livelock > > > > as usual, for timeout based next OOM victim selection is not implemented. > > > > > > What we should be doing is have the OOM reaper clear TIF_MEMDIE after > > > it's done. There is no reason to wait for and prioritize the exit of a > > > task that doesn't even have memory anymore. Once a task's memory has > > > been reaped, subsequent OOM invocations should evaluate anew the most > > > desirable OOM victim. > > > > This is an interesting idea. It definitely sounds better than timeout > > based solutions. I will cook up a patch for this. The API between oom > > killer and the reaper has to change slightly but that shouldn't be a big > > deal. > > That is part of what I suggested at > http://lkml.kernel.org/r/201512052133.IAE00551.LSOQFtMFFVOHOJ@xxxxxxxxxxxxxxxxxxx . > | What about marking current OOM victim unkillable by updating > | victim->signal->oom_score_adj to OOM_SCORE_ADJ_MIN and clearing victim's > | TIF_MEMDIE flag when the victim is still alive for a second after > | oom_reap_vmas() completed? Sorry, I must have missed this part. I have added your Suggested-by to the patch description. > Can we update victim's oom_score_adj as well? Otherwise, the OOM killer > might choose the same victim if victim's oom_score_adj was set to 1000. Yes I've done that in the patch I am testing ATM. -- Michal Hocko SUSE Labs -- 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>