Hi! > > > refrigerator_called is only reset after try_to_freeze_tasks() has found it > > > equal to one. There is only a small window between checking it in > > > wait_event_timeout() and resetting it, > > > > Yes. > > > > > but then we go to send freeze requests > > > to the remaining tasks and we count 'todo' from the start, so that shouldn't > > > be a problem. > > > > ... and we find the task which is not frozen() yet, but which has already passed > > the "set condition and wakeup", increment todo, and wait for the event. If it was > > the last task, we will sleep until timeout. > > > > I agree, this is not fatal and unlikely, but still it is a race. I think it is > > better to move this code down, after frozen_process(). > > OK, I see your point. The updated patch is appended. > > > (offtopic: strictly speaking, we don't even need the "refrigerator_called", we > > only need the wait_queue_head_t. try_to_freeze_tasks() just adds the "current" > > to wq at the very start of the main loop). > > Hmm, yes, I think so. Ok, could we just do schedule_timeout(HZ/10) or something, but when we _know_ we woke someone, wakeup() that task? No new variables, keep existing logic. That should still get most of the benefits, and be two liner, no? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
