On Wed 29-06-16 22:24:24, Oleg Nesterov wrote: > On 06/28, Michal Hocko wrote: > > > > On Mon 27-06-16 22:40:17, Oleg Nesterov wrote: > > > > > > Ah, but this is clear, note the "Ignoring the obvious races" above. > > > Can't we fix this race? I am a bit lost, but iirc we want this anyway > > > to ensure that we do not set TIF_MEMDIE if ->mm == NULL ? > > > > This is not about a race it is about not reaching exit_oom_victim and > > unblock the oom killer from selecting another victim. > > I understand. What I do not understand why we can't rely on MMF_OOM_REAPED > if we ensure that TIF_MEMDIE can only be set if the victim did not call > exit_oom_victim() yet. > > OK, please forget, I already got lost and right now I don't even have the > uptodate -mm tree sources. > > > > Hmm. Although I am not sure I really understand the "may block for > > > unbounded period ..." above. Do you mean khugepaged_exit? > > > > __mmput->exit_aio can wait for IO to complete and who knows what that > > might depend on. > > Yes, but I was confused by "waiting for somebody else's memory allocation", > I do not this this apllies to exit_aio. To be honest I really don't know. I am just assuming the worst. And IO sometimes need to allocate to move on. > Nevermind, > > > Who knows how many others are lurking there. > > Yes, yes, I agree. Just I wrongly thought Tetsuo meant something particular. I guess we just want to be conservative here and make sure we do not want to depend on the particular implementation details. -- 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>