Re: [PATCH] cpufreq: Limit resolving a frequency to policy min/max

[Shivnandan Kumar]

Hi Rafael,

Thanks for reviewing the change.

On 2/23/2024 12:52 AM, Rafael J. Wysocki wrote:
> On Thu, Feb 22, 2024 at 9:35 AM Shivnandan Kumar
> <quic_kshivnan@xxxxxxxxxxx> wrote:
> > Resolving a frequency to an efficient one should not transgress policy->max
> > (which can be set for thermal reason) and policy->min. Currently there is
> > possibility where scaling_cur_freq can exceed scaling_max_freq when
> > scaling_max_freq is inefficient frequency. Add additional check to ensure
> > that resolving a frequency will respect policy->min/max.
> >
> > Fixes: 1f39fa0dccff ("cpufreq: Introducing CPUFREQ_RELATION_E")
> > Signed-off-by: Shivnandan Kumar <quic_kshivnan@xxxxxxxxxxx>
> > ---
> >   include/linux/cpufreq.h | 18 +++++++++++++++++-
> >   1 file changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> > index afda5f24d3dd..42d98b576a36 100644
> > --- a/include/linux/cpufreq.h
> > +++ b/include/linux/cpufreq.h
> > @@ -1021,6 +1021,19 @@ static inline int cpufreq_table_find_index_c(struct cpufreq_policy *policy,
> >                                                     efficiencies);
> >   }
> >
> > +static inline bool cpufreq_table_index_is_in_limits(struct cpufreq_policy *policy,
> > +                                                   int idx)
>
> This is not really about the index only, but about the frequency at
> that index too, so I'd call the function differently.

ACK

> > +{
> > +       unsigned int freq;
> > +
> > +       if (idx < 0)
> > +               return false;
> > +
> > +       freq = policy->freq_table[idx].frequency;
> > +
> > +       return (freq == clamp_val(freq, policy->min, policy->max));
>
> Redundant outer parens.

ACK


> > +}
> > +
> >   static inline int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
> >                                                   unsigned int target_freq,
> >                                                   unsigned int relation)
> > @@ -1054,7 +1067,10 @@ static inline int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
> >                  return 0;
> >          }
> >
> > -       if (idx < 0 && efficiencies) {
> > +       /*
> > +        * Limit frequency index to honor policy->min/max
> > +        */
>
> This comment need not be multi-line.

ACK
I will make the changes in next patch set.

Thanks
Shivnandan

> > +       if (!cpufreq_table_index_is_in_limits(policy, idx) && efficiencies) {
> >                  efficiencies = false;
> >                  goto retry;
> >          }
> > --
>
> Thanks!