Re: [PATCH -mm] swsusp: Freeze filesystems during suspend (rev. 2)

Andrew Morton
2006-11-01T21:21:33Z

On Wed, 1 Nov 2006 21:27:17 +0100
"Rafael J. Wysocki" <rjw@sisk.pl> wrote:

> On Wednesday, 1 November 2006 20:45, Andrew Morton wrote:
> > On Wed, 1 Nov 2006 18:53:07 +0100
> > "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
> >
> > > +void thaw_processes(void)
> > > +{
> > > + printk("Restarting tasks ... ");
> > > + __thaw_tasks(FREEZER_KERNEL_THREADS);
> > > + thaw_filesystems();
> > > + __thaw_tasks(FREEZER_USER_SPACE);
> > > + schedule();
> > > + printk("done.\n");
> > > +}
> > >
> > > - read_unlock(&tasklist_lock);
> > > +void thaw_kernel_threads(void)
> > > +{
> > > + printk("Restarting kernel threads ... ");
> > > + __thaw_tasks(FREEZER_KERNEL_THREADS);
> > > schedule();
> > > printk("done.\n");
> > > }
> >
> > what do these random-looking schedule()s do??
>
> My understanding is that they allow the thawed tasks to actually exit
> the refrigerator, because __thaw_tasks() only changes their states.

I'd be surprised if this is doing what we thing it's doing. Calling
schedule() in state TASK_RUNNING is usually a no-op. It'll only actually
switch to another task if the scheduler decides that this task has expired
its timeslice, or another higher-priority task has become runnable, etc.