linux-kernel - [PATCH AUTOSEL 6.6 4/6] cpufreq: Use the fixed and coherent frequency for scaling capacity

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Date: Mon, 15 Jan 2024 19:08:59 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Vincent Guittot <vincent.guittot@...aro.org>,
	Ingo Molnar <mingo@...nel.org>,
	Lukasz Luba <lukasz.luba@....com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	Sasha Levin <sashal@...nel.org>,
	linux-pm@...r.kernel.org
Subject: [PATCH AUTOSEL 6.6 4/6] cpufreq: Use the fixed and coherent frequency for scaling capacity

From: Vincent Guittot <vincent.guittot@...aro.org>

[ Upstream commit 599457ba15403037b489fe536266a3d5f9efaed7 ]

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@...aro.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Tested-by: Lukasz Luba <lukasz.luba@....com>
Reviewed-by: Lukasz Luba <lukasz.luba@....com>
Acked-by: Viresh Kumar <viresh.kumar@...aro.org>
Acked-by: Rafael J. Wysocki <rafael@...nel.org>
Link: https://lore.kernel.org/r/20231211104855.558096-3-vincent.guittot@linaro.org
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/cpufreq/cpufreq.c | 4 ++--
 include/linux/cpufreq.h   | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 60ed89000e82..8c4f9c2f9c44 100644
--- 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 71d186d6933a..738dcddf3cfe 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -1211,6 +1211,7 @@ 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;
-- 
2.43.0