On Sunday, 8 July 2007 14:09, Pavel Machek wrote: > 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. Yes, it will. > > 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? >From the image/filesystems integrity standpoint, yes, that should be sufficient. Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
