Re: pm-hibernate : possible circular locking dependency detected

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Tue, 2009-04-07 at 13:56 +0930, Rusty Russell wrote:
> On Sunday 05 April 2009 23:14:54 Ingo Molnar wrote:
> > 
> > * Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > 
> > > On Sunday 05 April 2009, Ming Lei wrote:
> > > > kernel version : one simple usb-serial patch against  commit
> > > > 6bb597507f9839b13498781e481f5458aea33620.
> > > > 
> > > > Thanks.
> > > 
> > > Hmm, CPU hotplug again, it seems.
> > > 
> > > I'm not sure who's the maintainer at the moment.  Andrew, is that 
> > > Gautham?
> > 
> > CPU hotplug tends to land on the scheduler people's desk normally.
> > 
> > But i'm not sure that's the real thing here - key appears to be this 
> > work_on_cpu() worklet by the cpufreq code:
> 
> Looks like this will be fixed by Andrew's work-on-cpu-in-own-thread
> patch which I just put out the pull request for.

Would it make sense to teach it about a short-circuit like:

work_on_cpu() {

  if (cpumask_weight(current->cpus_allowed) == 1 && 
      smp_processor_id() == cpu)
    return do_work_right_here();

  queue_the_bugger();
}

?