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

On 24-06-21, 10:48, Ionela Voinescu wrote:

On Monday 21 Jun 2021 at 14:49:37 (+0530), Viresh Kumar wrote:

quoted

The Frequency Invariance Engine (FIE) is providing a frequency scaling
correction factor that helps achieve more accurate load-tracking.

[..]

quoted

+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 ?

quoted

+		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