On Tue, Nov 29, 2011 at 07:34:28PM +0100, Borislav Petkov wrote:
> On Tue, Nov 29, 2011 at 01:04:14PM -0500, Konrad Rzeszutek Wilk wrote:
> > This patch:
> >
> > commit d91ee5863b71e8c90eaf6035bff3078a85e2e7b5
> > Author: Len Brown <len.brown@xxxxxxxxx>
> > Date: Fri Apr 1 18:28:35 2011 -0400
> >
> > cpuidle: replace xen access to x86 pm_idle and default_idle
> >
> > ..scribble on pm_idle and access default_idle,
> > have it simply disable_cpuidle() so acpi_idle will not load and
> > architecture default HLT will be used.
> >
> > idea was to have one call - disable_cpuidle() which would make
> > pm_idle not be molested by other code. It disallows cpuidle_idle_call
> > and acpi_idle_call to not set pm_idle (which is excellent). But the
>
> what is acpi_idle_call, I can't find it anywhere.
You are right. I had "acpi_idle_enter_*" and its friend in mind. Which
are called from the cpuidle_idle_call.
Let me fix that comment up.
>
> > amd_e400_idle and mwait_idle can still setup pm_idle which we really
> > do not want.
>
> This is not the case: rather select_idle_routine()/idle_setup() sets
> pm_idle.
Yes. Let me fix up the comment.
>
> [..]
>
> > +bool set_pm_idle_to_default()
> > +{
> > + if (!pm_idle) {
> > + pm_idle = default_idle;
> > + return true;
> > + }
> > + return false;
> > +}
>
> I don't understand what you're trying to achieve here? Do you want
> default_idle to be always the pm_idle for xen or what is the deal here?
Yes (always want default_idle).
>
> If yes, then simply do:
>
> bool set_pm_idle_to_default(void) // remember to add "void" for no function args
> {
> bool ret = !!pm_idle;
>
> pm_idle = default_idle;
That would work too.
>
> return ret;
>
> }
>
> ...
>
> > void stop_this_cpu(void *dummy)
> > {
> > local_irq_disable();
> > diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> > index 46d6d21..7506181 100644
> > --- a/arch/x86/xen/setup.c
> > +++ b/arch/x86/xen/setup.c
> > @@ -448,6 +448,6 @@ void __init xen_arch_setup(void)
> > #endif
> > disable_cpuidle();
> > boot_option_idle_override = IDLE_HALT;
> > -
> > + WARN_ON(!set_pm_idle_to_default());
>
> and then do
>
> WARN_ON(set_pm_idle_to_default());
>
> instead of having arbitrary confusing logic. This way you can warn
> whether something else set pm_idle already. Or?
That would work as well.
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