On Mon, Mar 29, 2010 at 01:46:30PM +0200, Oleg Nesterov wrote: > On 03/29, anfei wrote: > > > > On Sun, Mar 28, 2010 at 06:28:21PM +0200, Oleg Nesterov wrote: > > > On 03/28, anfei wrote: > > > > > > > > Assume thread A and B are in the same group. If A runs into the oom, > > > > and selects B as the victim, B won't exit because at least in exit_mm(), > > > > it can not get the mm->mmap_sem semaphore which A has already got. > > > > > > I see. But still I can't understand. To me, the problem is not that > > > B can't exit, the problem is that A doesn't know it should exit. All > > > > If B can exit, its memory will be freed, > > Which memory? I thought, we are talking about the memory used by ->mm ? > There is also a little kernel struct related to the task can be freed, but I think you are correct, the memory used by ->mm takes more effect, and it won't be freed even B exits. So I agree you on: " the problem is not that B can't exit, the problem is that A doesn't know it should exit. All threads should exit and free ->mm. Even if B could exit, this is not enough. And, to some extent, it doesn't matter if it holds mmap_sem or not. " Thanks, Anfei. > 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>