Re: pm-hibernate : possible circular locking dependency detected

From: Ingo Molnar
Date: Wed Apr 08 2009 - 08:27:56 EST



* Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote:

> On Tuesday 07 April 2009 16:35:53 Peter Zijlstra wrote:
> > On Tue, 2009-04-07 at 13:56 +0930, Rusty Russell wrote:
> > > 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();
>
> Does that happen much? I guess put a counter in and see?

a temporary tracepoint or trace_printk() for the workqueue tracer
would also tell this, without any long-term overhead (it will be
easy to remove it).

Ingo
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