linux-kernel - [PATCH v1 10/10] cpufreq: Pass policy pointer to ->update

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Message-ID: <8560367.NyiUUSuA9g@rjwysocki.net>
Date: Fri, 28 Mar 2025 21:48:54 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 Viresh Kumar <viresh.kumar@...aro.org>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
 Mario Limonciello <mario.limonciello@....com>,
 Sudeep Holla <sudeep.holla@....com>
Subject: [PATCH v1 10/10] cpufreq: Pass policy pointer to ->update_limits()

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Since cpufreq_update_limits() obtains a cpufreq policy pointer for the
given CPU and reference counts the corresponding policy object, it may
as well pass the policy pointer to the cpufreq driver's ->update_limits()
callback which allows that callback to avoid invoking cpufreq_cpu_get()
for the same CPU.

Accordingly, redefine ->update_limits() to take a policy pointer instead
of a CPU number and update both drivers implementing it, intel_pstate
and amd-pstate, as needed.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/cpufreq/amd-pstate.c   |    7 ++-----
 drivers/cpufreq/cpufreq.c      |    2 +-
 drivers/cpufreq/intel_pstate.c |   29 ++++++++++++++++++-----------
 include/linux/cpufreq.h        |    2 +-
 4 files changed, 22 insertions(+), 18 deletions(-)

--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -821,19 +821,16 @@
 	schedule_work(&sched_prefcore_work);
 }
 
-static void amd_pstate_update_limits(unsigned int cpu)
+static void amd_pstate_update_limits(struct cpufreq_policy *policy)
 {
-	struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);
 	struct amd_cpudata *cpudata;
 	u32 prev_high = 0, cur_high = 0;
 	bool highest_perf_changed = false;
+	unsigned int cpu = policy->cpu;
 
 	if (!amd_pstate_prefcore)
 		return;
 
-	if (!policy)
-		return;
-
 	if (amd_get_highest_perf(cpu, &cur_high))
 		return;
 
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2741,7 +2741,7 @@
 		return;
 
 	if (cpufreq_driver->update_limits)
-		cpufreq_driver->update_limits(cpu);
+		cpufreq_driver->update_limits(policy);
 	else
 		cpufreq_policy_refresh(policy);
 }
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -1353,14 +1353,9 @@
 		cpufreq_update_policy(cpu);
 }
 
-static bool intel_pstate_update_max_freq(struct cpudata *cpudata)
+static void __intel_pstate_update_max_freq(struct cpufreq_policy *policy,
+					   struct cpudata *cpudata)
 {
-	struct cpufreq_policy *policy __free(put_cpufreq_policy);
-
-	policy = cpufreq_cpu_get(cpudata->cpu);
-	if (!policy)
-		return false;
-
 	guard(cpufreq_policy_write)(policy);
 
 	if (hwp_active)
@@ -1370,16 +1365,28 @@
 			cpudata->pstate.max_freq : cpudata->pstate.turbo_freq;
 
 	refresh_frequency_limits(policy);
+}
+
+static bool intel_pstate_update_max_freq(struct cpudata *cpudata)
+{
+	struct cpufreq_policy *policy __free(put_cpufreq_policy);
+
+	policy = cpufreq_cpu_get(cpudata->cpu);
+	if (!policy)
+		return false;
+
+	__intel_pstate_update_max_freq(policy, cpudata);
 
 	return true;
 }
 
-static void intel_pstate_update_limits(unsigned int cpu)
+static void intel_pstate_update_limits(struct cpufreq_policy *policy)
 {
-	struct cpudata *cpudata = all_cpu_data[cpu];
+	struct cpudata *cpudata = all_cpu_data[policy->cpu];
+
+	__intel_pstate_update_max_freq(policy, cpudata);
 
-	if (intel_pstate_update_max_freq(cpudata))
-		hybrid_update_capacity(cpudata);
+	hybrid_update_capacity(cpudata);
 }
 
 static void intel_pstate_update_limits_for_all(void)
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -399,7 +399,7 @@
 	unsigned int	(*get)(unsigned int cpu);
 
 	/* Called to update policy limits on firmware notifications. */
-	void		(*update_limits)(unsigned int cpu);
+	void		(*update_limits)(struct cpufreq_policy *policy);
 
 	/* optional */
 	int		(*bios_limit)(int cpu, unsigned int *limit);