[PATCH v1.1 6/6] cpufreq: intel_pstate: Update the maximum CPU frequency consistently

From: Rafael J. Wysocki
Date: Thu Mar 28 2024 - 15:02:31 EST


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

There are 3 places at which the maximum CPU frequency may change,
store_no_turbo(), intel_pstate_update_limits() (when called by the
cpufreq core) and intel_pstate_notify_work() (when handling a HWP
change notification). Currently, cpuinfo.max_freq is only updated by
store_no_turbo() and intel_pstate_notify_work(), although it principle
it may be necessary to update it in intel_pstate_update_limits() either.

Make all of them mutually consistent.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---

v1 -> v1.1: Fix changelog (Srinivas).

---
drivers/cpufreq/intel_pstate.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -1153,18 +1153,32 @@ static void intel_pstate_update_policies
static void __intel_pstate_update_max_freq(struct cpudata *cpudata,
struct cpufreq_policy *policy)
{
+ intel_pstate_get_hwp_cap(cpudata);
+
policy->cpuinfo.max_freq = READ_ONCE(global.no_turbo) ?
cpudata->pstate.max_freq : cpudata->pstate.turbo_freq;
+
refresh_frequency_limits(policy);
}

static void intel_pstate_update_limits(unsigned int cpu)
{
- mutex_lock(&intel_pstate_driver_lock);
+ struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);

- cpufreq_update_policy(cpu);
+ if (!policy)
+ return;

- mutex_unlock(&intel_pstate_driver_lock);
+ __intel_pstate_update_max_freq(all_cpu_data[cpu], policy);
+
+ cpufreq_cpu_release(policy);
+}
+
+static void intel_pstate_update_limits_for_all(void)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ intel_pstate_update_limits(cpu);
}

/************************** sysfs begin ************************/
@@ -1311,7 +1325,7 @@ static ssize_t store_no_turbo(struct kob

mutex_unlock(&intel_pstate_limits_lock);

- intel_pstate_update_policies();
+ intel_pstate_update_limits_for_all();
arch_set_max_freq_ratio(no_turbo);

unlock_driver:
@@ -1595,7 +1609,6 @@ static void intel_pstate_notify_work(str
struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpudata->cpu);

if (policy) {
- intel_pstate_get_hwp_cap(cpudata);
__intel_pstate_update_max_freq(cpudata, policy);

cpufreq_cpu_release(policy);