On Fri, Feb 20, 2009 at 3:20 PM, Oliver Neukum <oliver@xxxxxxxxxx> wrote: > Am Samstag 21 Februar 2009 00:11:28 schrieb Arve Hjønnevåg: >> On Fri, Feb 20, 2009 at 2:05 PM, Oliver Neukum <oliver@xxxxxxxxxx> wrote: >> > Am Freitag 20 Februar 2009 11:46:55 schrieb Rafael J. Wysocki: >> >> On Thursday 19 February 2009, Oliver Neukum wrote: > >> > With the set of runnable processes.There's always a window between >> > evaluating the current set of runnable tasks and telling the kernel to >> > sleep. IMO the most elegant solution would be a task attribute that would >> > signal the kernel that a task should not count as keeping the system busy >> > even if it is runnable and trigger the sleep in kernel space. >> >> It is not always safe to enter suspend when no tasks are runnable. For >> instance, a key event could be on a user space queue, but the code >> that reads from that queue has been paged out. > > In that case you'd have a task waiting for IO. The driver should refuse > to suspend or wake up the system as IO is completed. It may be > inefficient to suspend for such a presumably short time, but it is not > a correctness issue. In that case, yes. My point was that no-runnable-tasks is not a sufficient indicator of whether suspend should fail or not. We have no control of what a user space thread is waiting for though. It could be waiting on a mutex that is locked by a thread that is marked not to prevent suspend. -- Arve Hjønnevåg _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
