On 03/12, Oleg Nesterov wrote: > > On 03/11, David Rientjes wrote: > > > > On Wed, 9 Mar 2011, Andrew Morton wrote: > > > > > If Oleg's test program cause a hang with > > > oom-prevent-unnecessary-oom-kills-or-kernel-panics.patch and doesn't > > > cause a hang without > > > oom-prevent-unnecessary-oom-kills-or-kernel-panics.patch then that's a > > > big problem for > > > oom-prevent-unnecessary-oom-kills-or-kernel-panics.patch, no? > > > > > > > It's a problem, but not because of > > oom-prevent-unnecessary-oom-kills-or-kernel-panics.patch. > > It is, afaics. oom-killer can't ussume that a single PF_EXITING && p->mm > thread is going to free the memory. > > > If we don't > > have this patch, then we have a trivial panic when an oom kill occurs in a > > cpuset with no other eligible processes, the oom killed thread group > > leader exits > > It is not clear what "leader exits" actually mean. OK, perhaps you mean > its ->mm == NULL. > > > but its other threads do not and they trigger oom kills > > themselves. for_each_process() does not iterate over these threads and so > > it finds no eligible threads to kill and then panics > > Could you explain what do you mean? No need to kill these threads, they > are already killed, we should wait until they all exit. > > > I'll look at Oleg's test case > > and see what can be done to fix that condition, but the answer isn't to > > ignore eligible threads that can be killed. > > Once again, they are already killed. Or I do not understand what you meant. > > Could you please explain the problem in more details? > > > Also. Could you please look at the patches I sent? > > [PATCH 1/1] oom_kill_task: mark every thread as TIF_MEMDIE > [PATCH v2 1/1] select_bad_process: improve the PF_EXITING check Cough. And both were not right, while_each_thread(p, t) needs the properly initialized "t". At least I warned they were not tested ;) > Note also the note about "p == current" check. it should be fixed too. I am resending the fixes above plus the new one. David, Kosaki, what do you think? Oleg. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>