On Mon, Aug 02, 2010 at 09:56:10PM -0700, Arve Hjønnevåg wrote: > 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. Excellent point -- I had completely missed this failure mode!!! Thanx, Paul _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
