Hi! > > And then you will face the problem of a user task doing I/O during > > hibernate after the atomic snapshot has been made. > > I don't think that this is possible in normal conditions. It would be possible > if, for example, the task were waiting for an unavailable resource and that > resource became available after the hibernation image had been created. > In that case, however, to do any damage, the task would have to cause some > filesystem-related data to be flushed in the same syscall (ie. before returning > to user space). I agree that it is relatively unlikely to trigger (if you avoid freezing the tasks that were uninterruptible for long), but it will trigger in error cases etc. > Such situations may be prevented by a mechanizm detecting if any uniterruptible > and freezing task has been woken up after creating the image and aborting the > hibernation in that cases. For this purpose, we only need to add an > appropriate condition to try_to_wake_up() and make it start to trigger after, > for example, enabling the nonboot CPUs. I don't know how to do that mechanism... but if we knew where to trap filesystem writes, we could simply freeze at that point, and at that point only, 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
