Hi! > There is the problem with try_to_freeze_tasks() that it always loops until the > timeout expires, even if it is certain to fail much earlier. Namely, if there > are uninterruptible tasks waiting for some frozen tasks to let them continue, > try_to_freeze_tasks() will certainly fail and it shouldn't waste time in that > cases. > > To detect such situations, we can check if the number of tasks that haven't > frozen yet changes between subsequent iterations of the main loop in > try_to_freeze_tasks(). If this number hasn't been changing for sufficiently > long time (say, 250 ms), then most probably some uninterruptible tasks are > blocked by some frozen tasks and we should break out of this stalemate. Thus, > it seems reasonable to thaw the tasks that have already been frozen without > clearing the freeze requests of the tasks that are refusing to freeze. This > way, if these tasks are really blocked by the frozen ones, they will get extra > chance to freeze themselves after we have thawed the other tasks and before we > request those tasks to freeze again. Next, the freezing loop can be repeated > and so on, until all tasks are frozen or the timeout expires. I still don't quite like this patch... it is kind of trick we should not have to play. Can we at least get confirmation it helps in the FUSE case? 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
