Re: 3.2-rc2+: Reported regressions from 3.0 and 3.1

From: Borislav Petkov
Date: Tue Nov 29 2011 - 13:34:43 EST


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.

> 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.

[..]

> +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?

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;

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?

Thanks.

--
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
HRB Nr. 43632 WEEE Registernr: 129 19551
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/