Michal Hocko wrote: > > > > Please see http://lkml.kernel.org/r/201602151958.HCJ48972.FFOFOLMHSQVJtO@xxxxxxxxxxxxxxxxxxx . > > > > > > I have missed this one. Reading... > > > > > > Hmm, so you are not referring to OOM killed task but naturally exiting > > > thread which is racing with the OOM killer. I guess you have a point > > > there! Could you update the changelog with the above example and repost > > > please? > > > > > Yes and I resent that patch as v2. > > > > I think that the same problem exists for any task_will_free_mem()-based > > optimizations. Can we eliminate them because these optimized paths are not > > handled by the OOM reaper which means that we have no means other than > > "[PATCH 5/6] mm,oom: Re-enable OOM killer using timers." ? > > Well, only oom_kill_process usage of task_will_free_mem might be a > problem because out_of_memory operates on the current task so it must be > in the allocation path and access to memory reserves should help it to > continue. Allowing access to memory reserves by task_will_free_mem(current) in out_of_memory() will help current to continue, but that does not guarantee that current will not be later blocked at down_read(¤t->mm->mmap_sem). It is possible that one of threads sharing current thread's memory is calling out_of_memory() from mmap() and is waiting for current to set current->mm = NULL. > Wrt. oom_kill_process this will be more tricky. I guess we want to > teach oom_reaper to operate on such a task which would be a more robust > solution than removing the check altogether. > Thus, I think there is no difference between task_will_free_mem(current) case and task_will_free_mem(p) case. We want to teach the OOM reaper to operate whenever TIF_MEMDIE is set. But this means that we want mm_is_reapable() check because there might be !SIGKILL && !PF_EXITING threads when we run these optimized paths. We will need to use timer if mm_is_reapable() == false after all. Why don't you accept timer based workaround now, even if you have a plan to update the OOM reaper for handling these optimized paths? -- 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>