cpufreq: Use the fixed and coherent frequency for scaling capacity

cpuinfo.max_freq can change at runtime because of boost as an example. This
implies that the value could be different from the frequency that has been
used to compute the capacity of a CPU.

The new arch_scale_freq_ref() returns a fixed and coherent frequency
that can be used to compute the capacity for a given frequency.

[ Also fix a arch_set_freq_scale()  newline style wart in <linux/cpufreq.h>. ]

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20231211104855.558096-3-vincent.guittot@linaro.org

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 934d35f570b7a01e6c642c8f56c3568fa16191f4..44db4f59c4cc6cc839b062b8ab84efa6bad5b729 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -454,7 +454,7 @@ void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
 
        arch_set_freq_scale(policy->related_cpus,
                            policy->cur,
-                           policy->cpuinfo.max_freq);
+                           arch_scale_freq_ref(policy->cpu));
 
        spin_lock(&policy->transition_lock);
        policy->transition_ongoing = false;
@@ -2174,7 +2174,7 @@ unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
 
        policy->cur = freq;
        arch_set_freq_scale(policy->related_cpus, freq,
-                           policy->cpuinfo.max_freq);
+                           arch_scale_freq_ref(policy->cpu));
        cpufreq_stats_record_transition(policy, freq);
 
        if (trace_cpu_frequency_enabled()) {

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 1c5ca92a0555f510942e791987d19c075844e630..afda5f24d3ddc69e8bdaf5dfc0008f350dbd49a1 100644 (file)
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -1203,6 +1203,7 @@ void arch_set_freq_scale(const struct cpumask *cpus,
 {
 }
 #endif
+
 /* the following are really really optional */
 extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
 extern struct freq_attr cpufreq_freq_attr_scaling_boost_freqs;