Re: [PATCH V3 4/4] cpufreq: CPPC: Add support for frequency invariance

[Viresh Kumar]

On 24-06-21, 10:48, Ionela Voinescu wrote:
> On Monday 21 Jun 2021 at 14:49:37 (+0530), Viresh Kumar wrote:
> > The Frequency Invariance Engine (FIE) is providing a frequency scaling
> > correction factor that helps achieve more accurate load-tracking.
> [..]
> > +static void cppc_cpufreq_cpu_fie_exit(struct cpufreq_policy *policy)
> > +{
> > +	struct cppc_freq_invariance *cppc_fi;
> > +	int cpu;
> > +
> > +	if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
> > +		return;
> > +
> > +	/* policy->cpus will be empty here, use related_cpus instead */
> > +	topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_CPPC, policy->related_cpus);
> > +
> > +	for_each_cpu(cpu, policy->related_cpus) {
> > +		cppc_fi = &per_cpu(cppc_freq_inv, cpu);
> 
> Do you think it might be worth having here something like:
> 
> 		if (!cppc_fi->cpu_data)
> 			continue;
> 
> This would be to protect against cases where the platform does not boot
> with all CPUs or the module is loaded after some have already been
> offlined. Unlikely, but..

Even in that case policy->cpus will contain all offline+online CPUs (at ->init()
time), isn't it ?

> > +		irq_work_sync(&cppc_fi->irq_work);
> > +		kthread_cancel_work_sync(&cppc_fi->work);
> > +	}
> > +}
> 
> The rest of the code is almost the same as the original, so that is all
> from me :).
> 
> Thanks,
> Ionela.

-- 
viresh