From e7a1b32e43b194bbf930281ae7f5149c420cd122 Mon Sep 17 00:00:00 2001
From: Pierre Gondois <pierre.gondois@arm.com>
Date: Thu, 5 Oct 2023 15:41:20 +0200
Subject: [PATCH] cpufreq: Rebuild sched-domains when removing cpufreq driver
The Energy Aware Scheduler (EAS) relies on the schedutil governor.
When moving to/from the schedutil governor, sched domains must be
rebuilt to allow re-evaluating the enablement conditions of EAS.
This is done through sched_cpufreq_governor_change().
Having a cpufreq governor assumes a cpufreq driver is running.
Inserting/removing a cpufreq driver should trigger a re-evaluation
of EAS enablement conditions, avoiding to see EAS enabled when
removing a running cpufreq driver.
Rebuild the sched domains in schedutil's sugov_init()/sugov_exit(),
allowing to check EAS's enablement condition whenever schedutil
governor is initialized/exited from.
Move relevant code up in schedutil.c to avoid a split and conditional
function declaration.
Rename sched_cpufreq_governor_change() to sugov_eas_rebuild_sd().
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpufreq/cpufreq.c | 3 +-
include/linux/cpufreq.h | 8 -----
kernel/sched/cpufreq_schedutil.c | 55 +++++++++++++++++---------------
3 files changed, 30 insertions(+), 36 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 60ed89000e82d..4bc15634d49c8 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1544,7 +1544,7 @@ static int cpufreq_online(unsigned int cpu)
/*
* Register with the energy model before
- * sched_cpufreq_governor_change() is called, which will result
+ * sugov_eas_rebuild_sd() is called, which will result
* in rebuilding of the sched domains, which should only be done
* once the energy model is properly initialized for the policy
* first.
@@ -2652,7 +2652,6 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
ret = cpufreq_start_governor(policy);
if (!ret) {
pr_debug("governor change\n");
- sched_cpufreq_governor_change(policy, old_gov);
return 0;
}
cpufreq_exit_governor(policy);
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 71d186d6933a5..1c5ca92a0555f 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -1193,14 +1193,6 @@ static inline int of_perf_domain_get_sharing_cpumask(int pcpu, const char *list_
}
#endif
-#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
-void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
- struct cpufreq_governor *old_gov);
-#else
-static inline void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
- struct cpufreq_governor *old_gov) { }
-#endif
-
extern unsigned int arch_freq_get_on_cpu(int cpu);
#ifndef arch_set_freq_scale
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index f3a95def49cca..492ec650d48fe 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -555,6 +555,31 @@ static const struct kobj_type sugov_tunables_ktype = {
/********************** cpufreq governor interface *********************/
+#ifdef CONFIG_ENERGY_MODEL
+static void rebuild_sd_workfn(struct work_struct *work)
+{
+ rebuild_sched_domains_energy();
+}
+
+static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
+
+/*
+ * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
+ * on governor changes to make sure the scheduler knows about it.
+ */
+static void sugov_eas_rebuild_sd(void)
+{
+ /*
+ * When called from the cpufreq_register_driver() path, the
+ * cpu_hotplug_lock is already held, so use a work item to
+ * avoid nested locking in rebuild_sched_domains().
+ */
+ schedule_work(&rebuild_sd_work);
+}
+#else
+static inline void sugov_eas_rebuild_sd(void) { };
+#endif
+
struct cpufreq_governor schedutil_gov;
static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
@@ -709,6 +734,8 @@ static int sugov_init(struct cpufreq_policy *policy)
if (ret)
goto fail;
+ sugov_eas_rebuild_sd();
+
out:
mutex_unlock(&global_tunables_lock);
return 0;
@@ -750,6 +777,8 @@ static void sugov_exit(struct cpufreq_policy *policy)
sugov_kthread_stop(sg_policy);
sugov_policy_free(sg_policy);
cpufreq_disable_fast_switch(policy);
+
+ sugov_eas_rebuild_sd();
}
static int sugov_start(struct cpufreq_policy *policy)
@@ -833,29 +862,3 @@ struct cpufreq_governor *cpufreq_default_governor(void)
#endif
cpufreq_governor_init(schedutil_gov);
-
-#ifdef CONFIG_ENERGY_MODEL
-static void rebuild_sd_workfn(struct work_struct *work)
-{
- rebuild_sched_domains_energy();
-}
-static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
-
-/*
- * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
- * on governor changes to make sure the scheduler knows about it.
- */
-void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
- struct cpufreq_governor *old_gov)
-{
- if (old_gov == &schedutil_gov || policy->governor == &schedutil_gov) {
- /*
- * When called from the cpufreq_register_driver() path, the
- * cpu_hotplug_lock is already held, so use a work item to
- * avoid nested locking in rebuild_sched_domains().
- */
- schedule_work(&rebuild_sd_work);
- }
-
-}
-#endif
--
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