Thread (15 messages) flat view 15 messages, 3 authors, 2020-06-23

Re: [PATCH 2/2] cpufreq: Specify default governor on command line

From: Viresh Kumar <viresh.kumar@linaro.org>
Date: 2020-06-16 04:31:49
Also in: linux-pm, lkml

On 15-06-20, 17:55, Quentin Perret wrote:
+static void cpufreq_get_default_governor(void)
+{
+	default_governor = cpufreq_parse_governor(cpufreq_param_governor);
+	if (!default_governor) {
+		if (*cpufreq_param_governor)
+			pr_warn("Failed to find %s\n", cpufreq_param_governor);
+		default_governor = cpufreq_default_governor();
A module_get() never happened for this case and so maybe a
module_put() should never get called.
quoted hunk ↗ jump to hunk
+	}
+}
+
+static void cpufreq_put_default_governor(void)
+{
+	if (!default_governor)
+		return;
+	module_put(default_governor->owner);
+	default_governor = NULL;
+}
+
 static int cpufreq_init_governor(struct cpufreq_policy *policy)
 {
 	int ret;
@@ -2701,6 +2721,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
 
 	if (driver_data->setpolicy)
 		driver_data->flags |= CPUFREQ_CONST_LOOPS;
+	else
+		cpufreq_get_default_governor();
 
 	if (cpufreq_boost_supported()) {
 		ret = create_boost_sysfs_file();
@@ -2769,6 +2791,7 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver)
 	subsys_interface_unregister(&cpufreq_interface);
 	remove_boost_sysfs_file();
 	cpuhp_remove_state_nocalls_cpuslocked(hp_online);
+	cpufreq_put_default_governor();
 
 	write_lock_irqsave(&cpufreq_driver_lock, flags);
 
@@ -2792,4 +2815,5 @@ static int __init cpufreq_core_init(void)
 	return 0;
 }
And since this is a per boot thing, there is perhaps no need of doing
these at driver register/unregister, I would rather do it at:
cpufreq_core_init() time itself and so we will never need to run
cpufreq_put_default_governor() and so can be removed.

And another thing I am not able to understand (despite you commenting
about that in the commit log) is what happens if the default governor
chosen is built as a module ?

-- 
viresh
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