On Sun, Aug 1, 2010 at 6:10 PM, Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote: > On Sun, Aug 01, 2010 at 03:47:08PM -0700, Arjan van de Ven wrote: ... >> Another one: freezing whole cgroups..... we have that today. it >> actually works quite well.... of course the hard part is the decision >> what to put in which cgroup, and at what frequency and duration you let >> cgroups run. > > Indeed, the Android guys seemed to be quite excited by cgroup freezing > until they thought about the application-classification problem. > Seems like it should be easy for some types of applications, but I do > admit that apps can have non-trivial and non-obvious dependencies. > The dependencies is what made this solution uninteresting to us. For instance, we currently use cgroup scheduling to reduce the impact of some background tasks, but we occasionally saw a watchdog restart of the system process were critical services were waiting on a kernel mutex owned by a background task for more than 20 seconds. If we froze a cgroup instead, we would not hit this particular problem since tasks cannot be frozen while executing kernel code the same way they can be preempted, but nothing prevents a task from being frozen while holding a user-space resource. -- Arve Hjønnevåg _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
