Re: Fw: [RFC] Strange code in cpu_idle()

[Zwane Mwaikambo]

On Mon, 6 Dec 2004, Paul E. McKenney wrote:

> I am not going to claim to thoroughly understand the power-management
> code, but do have an additional question.
> 
> What happens if the processor became aware of a new grace period just
> before entering pm_idle?  I could imagine this code simply refusing
> to power down the processor if there was a pending grace period, but
> I don't see any sign of this.  I could also imagine somehow deferring
> interrupts until pm_idle exits.  I don't see anything that looks like
> it does this, but don't claim to be any sort of power-management
> expert.

Are you referring to the synchronize_kernel side? That's basically unload 
module path so it's ok if it sits there for a bit, but it should only last 
for as long as the next interrupt, which would be a pretty short perid 
considering HZ=1000. But the usage still has a race and hence invalid as 
pointed out by Dipankar

Thanks,
	Zwane

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