Re: [PATCH v2 01/13] cpufreq: Allow restricting to internal governors only

[Jason Andryuk <jandryuk@xxxxxxxxx>]

On Mon, Aug 15, 2022 at 10:22 AM Jan Beulich <jbeulich@xxxxxxxx> wrote:
>
> On 10.08.2022 21:29, Jason Andryuk wrote:
> > For hwp, the standard governors are not usable, and only the internal
> > one is applicable.  Add the cpufreq_governor_internal boolean to
> > indicate when an internal governor, like hwp-internal, will be used.
> > This is set during presmp_initcall, so that it can suppress governor
> > registration during initcall.
>
> At which point ...
>
> >  Only a governor with a name containing
> > "-internal" will be allowed in that case.
> >
> > This way, the unuseable governors are not registered, so they internal
> > one is the only one returned to userspace.  This means incompatible
> > governors won't be advertised to userspace.
> >
> > Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx>
> > ---
> > v2:
> > Switch to "-internal"
> > Add blank line in header
> > ---
> >  xen/drivers/cpufreq/cpufreq.c      | 5 +++++
> >  xen/include/acpi/cpufreq/cpufreq.h | 2 ++
> >  2 files changed, 7 insertions(+)
> >
> > diff --git a/xen/drivers/cpufreq/cpufreq.c b/xen/drivers/cpufreq/cpufreq.c
> > index a94520ee57..1fdd63d7b5 100644
> > --- a/xen/drivers/cpufreq/cpufreq.c
> > +++ b/xen/drivers/cpufreq/cpufreq.c
> > @@ -57,6 +57,7 @@ struct cpufreq_dom {
> >  };
> >  static LIST_HEAD_READ_MOSTLY(cpufreq_dom_list_head);
> >
> > +bool __read_mostly cpufreq_governor_internal;
>
> ... I expect this can be __initdata? With that adjustment

Patch 09 "xen: Add SET_CPUFREQ_HWP xen_sysctl_pm_op" uses it at
runtime.  But I think it can be dropped since there is a check of the
governor name.  I'll add __initdata.

> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>

Thank you,
Jason