Re: [PATCH] cpuidle: move field disable from per-driver to per-cpu

From: Andrew Morton
Date: Fri Jun 22 2012 - 19:10:26 EST


On Thu, 14 Jun 2012 10:52:48 +0800
ShuoX Liu <shuox.liu@xxxxxxxxx> wrote:

> From: ShuoX Liu <shuox.liu@xxxxxxxxx>
>
> Andrew J.Schorr raises a question. When he changes the disable setting
> on a single CPU, it affects all the other CPUs. Basically, currently,
> the disable field is per-driver instead of per-cpu. All the C states of
> the same driver are shared by all CPU in the same machine.
>
> Below patch changes field disable to per-cpu, so we could set this
> separately for each cpu.
>
> ...
>
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -34,6 +34,7 @@ struct cpuidle_driver;
> struct cpuidle_state_usage {
> void *driver_data;
>
> + unsigned long long disable;

hrmpf. We're using 64 bits for this where one bit would do, afaict
because the magic macros in drivers/cpuidle/sysfs.c are using %llu.

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