Re: 2.6.22-rc1: Broken suspend on SMP with tifm

From: Oleg Nesterov
Date: Sun May 13 2007 - 17:34:27 EST


On 05/13, Rafael J. Wysocki wrote:
>
> > > On Sunday, 13 May 2007 22:30, Oleg Nesterov wrote:
> > > >
> > > > I think the better fix (at least for now) is
> > > >
> > > > - #define create_freezeable_workqueue(name) __create_workqueue((name), 0, 1)
> > > > + #define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1)
> > > >
> > > > Alex, do you really need a multithreaded wq?
> > > >
> > > > Rafael, what do you think?
> > >
> Sure, if a singlethread workqueue is sufficient for Alex, I agree that this
> would be preferable.

Great. Alex?

> @@ -819,20 +843,31 @@ static int __devinit workqueue_cpu_callb
>
> +
> + case CPU_DEAD_FROZEN:
> + if (wq->freezeable) {
> + take_over_work(wq, cpu);
> + thaw_process(cwq->thread);

Suppose that PF_NOFREEZE task T does flush_workqueue(), and CPU 1 has pending
works. T does flush_cpu_workqueue(0), CPU_DEAD_FROZEN moves works from CPU 1
to CPU 0, T does flush_cpu_workqueue(1) and finds nothing.

Oleg.

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