On Wednesday, October 22, 2014 04:22:26 PM Michal Hocko wrote: > On Wed 22-10-14 16:39:12, Rafael J. Wysocki wrote: > > On Tuesday, October 21, 2014 04:29:39 PM Michal Hocko wrote: > > > On Tue 21-10-14 16:41:07, Rafael J. Wysocki wrote: > > > > On Tuesday, October 21, 2014 04:11:59 PM Michal Hocko wrote: > > > [...] > > > > > OK, incremental diff on top. I will post the complete patch if you are > > > > > happier with this change > > > > > > > > Yes, I am. > > > --- > > > From 9ab46fe539cded8e7b6425b2cd23ba9184002fde Mon Sep 17 00:00:00 2001 > > > From: Michal Hocko <mhocko@xxxxxxx> > > > Date: Mon, 20 Oct 2014 18:12:32 +0200 > > > Subject: [PATCH -v2] OOM, PM: OOM killed task shouldn't escape PM suspend > > > > > > PM freezer relies on having all tasks frozen by the time devices are > > > getting frozen so that no task will touch them while they are getting > > > frozen. But OOM killer is allowed to kill an already frozen task in > > > order to handle OOM situtation. In order to protect from late wake ups > > > OOM killer is disabled after all tasks are frozen. This, however, still > > > keeps a window open when a killed task didn't manage to die by the time > > > freeze_processes finishes. > > > > > > Reduce the race window by checking all tasks after OOM killer has been > > > disabled. This is still not race free completely unfortunately because > > > oom_killer_disable cannot stop an already ongoing OOM killer so a task > > > might still wake up from the fridge and get killed without > > > freeze_processes noticing. Full synchronization of OOM and freezer is, > > > however, too heavy weight for this highly unlikely case. > > > > > > Introduce and check oom_kills counter which gets incremented early when > > > the allocator enters __alloc_pages_may_oom path and only check all the > > > tasks if the counter changes during the freezing attempt. The counter > > > is updated so early to reduce the race window since allocator checked > > > oom_killer_disabled which is set by PM-freezing code. A false positive > > > will push the PM-freezer into a slow path but that is not a big deal. > > > > > > Changes since v1 > > > - push the re-check loop out of freeze_processes into > > > check_frozen_processes and invert the condition to make the code more > > > readable as per Rafael > > > > I've applied that along with the rest of the series, but what about the > > following cleanup patch on top of it? > > Sure, looks good to me. I'll apply it then, thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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>