Michal Hocko wrote: > On Tue 19-07-16 19:36:40, Tetsuo Handa wrote: > > Michal Hocko wrote: > > > On Tue 19-07-16 08:40:48, Michal Hocko wrote: > > > > On Tue 19-07-16 06:30:42, Tetsuo Handa wrote: > > > > > Michal Hocko wrote: > > > > > > I really do not think that this unlikely case really has to be handled > > > > > > now. We are very likely going to move to a different model of oom victim > > > > > > detection soon. So let's do not add new hacks. exit_oom_victim from > > > > > > oom_kill_process just looks like sand in eyes. > > > > > > > > > > Then, please revert "mm, oom: hide mm which is shared with kthread or global init" > > > > > ( http://lkml.kernel.org/r/1466426628-15074-11-git-send-email-mhocko@xxxxxxxxxx ). > > > > > I don't like that patch because it is doing pointless find_lock_task_mm() test > > > > > and is telling a lie because it does not guarantee that we won't hit OOM livelock. > > > > > > > > The above patch doesn't make the situation worse wrt livelock. I > > > > consider it an improvement. It adds find_lock_task_mm into > > > > oom_scan_process_thread but that can hardly be worse than just the > > > > task->signal->oom_victims check because we can catch MMF_OOM_REAPED. If > > > > we are mm loss, which is a less likely case, then we behave the same as > > > > with the previous implementation. > > > > > > > > So I do not really see a reason to revert that patch for now. > > > > > > And that being said. If you strongly disagree with the wording then what > > > about the following: > > > " > > > In order to help a forward progress for the OOM killer, make sure that > > > this really rare cases will not get into the way and hide the mm from the > > > oom killer by setting MMF_OOM_REAPED flag for it. oom_scan_process_thread > > > will ignore any TIF_MEMDIE task if it has MMF_OOM_REAPED flag set to catch > > > these oom victims. > > > > > > After this patch we should guarantee a forward progress for the OOM killer > > > even when the selected victim is sharing memory with a kernel thread or > > > global init as long as the victims mm is still alive. > > > " > > > > No, I don't like "as long as the victims mm is still alive" exception. > > Why? Because of the wording or in principle? Making a _guarantee without exceptions now_ can allow other OOM livelock handlings (e.g. http://lkml.kernel.org/r/20160719074935.GC9486@xxxxxxxxxxxxxx ) to rely on the OOM reaper. We can improve OOM reaper after we made a guarantee without exceptions now. -- 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>