On Wed, 9 Jun 2010 22:14:30 +0200 Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > > in this case since it would > > not be allocating memory without p->mm. > > This thread will not allocate the memory, yes. But its sub-threads can. > And select_bad_process() can constantly return the same (dead) thread P, > badness() inspects ->mm under find_lock_task_mm() which finds the thread > with the valid ->mm. > > OK. Probably this doesn't matter. I don't know if task_in_mem_cgroup(task) > was fixed or not, but currently it also looks at task->mm and thus have > the same boring problem: it is trivial to make the memory-hog process > invisible to oom. Unless I missed something, of course. > HmHm...your concern is that there is a case when mem_cgroup_out_of_memory() can't kill anything ? Now, memcg doesn't return -ENOMEM in usual case. So, it loops until there are some available memory under its limit. Then, if memory_cgroup_out_of_memory() can kill a process in several trial, we'll not have terrible problem. (even if it's slow.) Hmm. What I can't understand is whether there is a case when PF_EXITING thread never exit. If so, we need some care (in memcg?) Thanks, -Kame -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>