Re: PATCH: Fix race in cpu_down (hotplug cpu)

Shaohua Li
2005-09-19T07:06:29Z

On Mon, 2005-09-19 at 16:36 +1000, Nick Piggin wrote:
> On Mon, 2005-09-19 at 14:37 +0800, Shaohua Li wrote:
> > On Mon, 2005-09-19 at 11:53 +0530, Srivatsa Vaddagiri wrote:
>
> > > default_idle should be fine as it is. IOW it should not cause __cpu_die to
> > > timeout.
> > Why default_idle should be fine? it can be preempted before the
> > 'local_irq_disable' check. Even with Nigel's patch, there is a very
> > small window at safe_halt (after 'sti' but before 'hlt').
> >
>
> Ah, actually I have a patch which makes all CPU idle threads
> run with preempt disabled and only enable preempt when scheduling.
> Would that help?
It should solve the issue to me. Should we take care of the latency?
acpi_processor_idle might execute for a long time.

Thanks,
Shaohua