[PATCH v1 2/3] cpufreq: CPPC: Add per_cpu efficiency_class

[Marc Zyngier]

On Thu, 17 Mar 2022 16:07:01 +0000,
Pierre Gondois <pierre.gondois at arm.com> wrote:
> 
> >> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> >> index 27df5c1e6baa..56637cbea5d6 100644
> >> --- a/arch/arm64/kernel/smp.c
> >> +++ b/arch/arm64/kernel/smp.c
> >> @@ -512,6 +512,7 @@ struct acpi_madt_generic_interrupt
> >> *acpi_cpu_get_madt_gicc(int cpu)
> >>   {
> >>   	return &cpu_madt_gicc[cpu];
> >>   }
> >> +EXPORT_SYMBOL(acpi_cpu_get_madt_gicc);
> > 
> > Why not EXPORT_SYMBOL_GPL()?
> 
> From what I understand, this could be made EXPORT_SYMBOL_GPL().
> The only reason was that the other symbol exportation in the
> file wasn't restricted to GPL.

I'm personally keen on keeping this for GPL code only, just like the
current code is. If there is a further need to relax this, we can
discuss it separately.

> 
> > 
> >> 
> >>   /*
> >>    * acpi_map_gic_cpu_interface - parse processor MADT entry
> >> diff --git a/drivers/cpufreq/cppc_cpufreq.c
> >> b/drivers/cpufreq/cppc_cpufreq.c
> >> index 8f950fe72765..a6cd95c3b474 100644
> >> --- a/drivers/cpufreq/cppc_cpufreq.c
> >> +++ b/drivers/cpufreq/cppc_cpufreq.c
> >> @@ -422,12 +422,66 @@ static unsigned int
> >> cppc_cpufreq_get_transition_delay_us(unsigned int cpu)
> >>   	return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
> >>   }
> >> 
> >> +static bool efficiency_class_populated;
> >> +static DEFINE_PER_CPU(unsigned int, efficiency_class);
> >> +
> >> +static int populate_efficiency_class(void)
> >> +{
> >> +	unsigned int min = UINT_MAX, max = 0, class;
> >> +	struct acpi_madt_generic_interrupt *gicc;
> >> +	int cpu;
> >> +
> >> +	for_each_possible_cpu(cpu) {
> >> +		gicc = acpi_cpu_get_madt_gicc(cpu);
> >> +		if (!gicc)
> >> +			return -ENODEV;
> > 
> > How can that happen if you made it here using ACPI?
> 
> This is effectively an extra check. This could be removed.

Please do.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.