Re: [Xen-devel] [PATCH] xen/arm: disable cpuidle when linux is running as dom0
On 17 July 2013 14:28, Stefano Stabellini wrote: > On Mon, 15 Jul 2013, Konrad Rzeszutek Wilk wrote: >> On Mon, Jul 15, 2013 at 03:21:41PM +0100, Julien Grall wrote: >> > When linux is running as dom0, Xen doesn't show the physical cpu but a >> > virtual CPU. >> > On some ARM SOC (for instance the exynos 5250), linux registers callbacks >> > for cpuidle. When these callbacks are called, they will modify >> > directly the physical cpu not the virtual one. >> It can impact the whole board >> > instead of dom0. > > Certainly this is something that should be fixed at the hypervisor level > too. However I agree that Linux should try to avoid doing that when > running on Xen. > > > >> Should you also call disable_cpufreq() ? > > Sounds like a good idea. > Julien, could you add that to this patch? I have checked with both the Arndale and Versatile Express without any issue. I will resend this patch with disable_cpufreq(). -- Julien Grall -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [Xen-devel] [PATCH] xen/arm: disable cpuidle when linux is running as dom0
On Mon, 15 Jul 2013, Konrad Rzeszutek Wilk wrote:
> On Mon, Jul 15, 2013 at 03:21:41PM +0100, Julien Grall wrote:
> > When linux is running as dom0, Xen doesn't show the physical cpu but a
> > virtual CPU.
> > On some ARM SOC (for instance the exynos 5250), linux registers callbacks
> > for cpuidle. When these callbacks are called, they will modify
> > directly the physical cpu not the virtual one.
> It can impact the whole board
> > instead of dom0.
Certainly this is something that should be fixed at the hypervisor level
too. However I agree that Linux should try to avoid doing that when
running on Xen.
> Should you also call disable_cpufreq() ?
Sounds like a good idea.
Julien, could you add that to this patch?
> >
> > Signed-off-by: Julien Grall
> > ---
> > arch/arm/xen/enlighten.c |7 +++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> > index 49839d8..a98999f 100644
> > --- a/arch/arm/xen/enlighten.c
> > +++ b/arch/arm/xen/enlighten.c
> > @@ -24,6 +24,8 @@
> > #include
> > #include
> > #include
> > +#include
> > +#include
> >
> > #include
> >
> > @@ -292,6 +294,11 @@ static int __init xen_pm_init(void)
> > {
> > pm_power_off = xen_power_off;
> > arm_pm_restart = xen_restart;
> > + /*
> > +* Making sure board specific code will not set up ops for
> > +* cpu idle.
> > +*/
> > + disable_cpuidle();
> >
> > return 0;
> > }
> > --
> > 1.7.10.4
> >
> >
> > ___
> > Xen-devel mailing list
> > xen-de...@lists.xen.org
> > http://lists.xen.org/xen-devel
>
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Re: [Xen-devel] [PATCH] xen/arm: disable cpuidle when linux is running as dom0
On 07/15/2013 04:25 PM, Konrad Rzeszutek Wilk wrote: > On Mon, Jul 15, 2013 at 03:21:41PM +0100, Julien Grall wrote: >> When linux is running as dom0, Xen doesn't show the physical cpu but a >> virtual CPU. >> On some ARM SOC (for instance the exynos 5250), linux registers callbacks >> for cpuidle. When these callbacks are called, they will modify >> directly the physical cpu not the virtual one. It can impact the whole board >> instead of dom0. > > Should you also call disable_cpufreq() ? I had some issue on the versatile express when cpufreq was disabled. I will give another try and see the exact error. -- Julien -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [Xen-devel] [PATCH] xen/arm: disable cpuidle when linux is running as dom0
On Mon, Jul 15, 2013 at 03:21:41PM +0100, Julien Grall wrote:
> When linux is running as dom0, Xen doesn't show the physical cpu but a
> virtual CPU.
> On some ARM SOC (for instance the exynos 5250), linux registers callbacks
> for cpuidle. When these callbacks are called, they will modify
> directly the physical cpu not the virtual one. It can impact the whole board
> instead of dom0.
Should you also call disable_cpufreq() ?
>
> Signed-off-by: Julien Grall
> ---
> arch/arm/xen/enlighten.c |7 +++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 49839d8..a98999f 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -24,6 +24,8 @@
> #include
> #include
> #include
> +#include
> +#include
>
> #include
>
> @@ -292,6 +294,11 @@ static int __init xen_pm_init(void)
> {
> pm_power_off = xen_power_off;
> arm_pm_restart = xen_restart;
> + /*
> + * Making sure board specific code will not set up ops for
> + * cpu idle.
> + */
> + disable_cpuidle();
>
> return 0;
> }
> --
> 1.7.10.4
>
>
> ___
> Xen-devel mailing list
> xen-de...@lists.xen.org
> http://lists.xen.org/xen-devel
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