Re: [PATCH v2 1/5] arch_topology: Introduce thermal pressure update function

[Lukasz Luba]

On 10/28/21 6:44 AM, Viresh Kumar wrote:
> On 15-10-21, 15:45, Lukasz Luba wrote:
> > +/**
> > + * topology_thermal_pressure_update() - Update thermal pressure for CPUs
> > + * @cpus	: The related CPUs for which capacity has been reduced
> > + * @capped_freq	: The maximum allowed frequency that CPUs can run at
>
> Maybe replace tabs with spaces here ?

Sure

> > + *
> > + * Update the value of thermal pressure for all @cpus in the mask. The
> > + * cpumask should include all (online+offline) affected CPUs, to avoid
> > + * operating on stale data when hot-plug is used for some CPUs. The
> > + * @capped_freq must be less or equal to the max possible frequency and
> > + * reflects the currently allowed max CPUs frequency due to thermal capping.
> > + * The @capped_freq must be provided in kHz.
> > + */
> > +void topology_thermal_pressure_update(const struct cpumask *cpus,
> > +				      unsigned long capped_freq)
> > +{
> > +	unsigned long max_capacity, capacity;
> > +	int cpu;
> > +
> > +	if (!cpus)
>
> I will drop this and let the kernel crash :)

OK :)

> > +		return;
> > +
> > +	cpu = cpumask_first(cpus);
> > +	max_capacity = arch_scale_cpu_capacity(cpu);
> > +
> > +	/* Convert to MHz scale which is used in 'freq_factor' */
> > +	capped_freq /= 1000;
>
> We should make sure capped_freq > freq_factor and WARN if not. This will also
> get rid of similar checks at the users.

OK, I'll change that.

Thank you for the review.

Regards,
Lukasz