Commit a97e293e authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

cpufreq: intel_pstate: Clear hybrid_max_perf_cpu before driver registration 



Modify intel_pstate_register_driver() to clear hybrid_max_perf_cpu
before calling cpufreq_register_driver(), so that asymmetric CPU
capacity scaling is not updated until hybrid_init_cpu_capacity_scaling()
runs down the road.  This is done in preparation for a subsequent
change adding asymmetric CPU capacity computation to the CPU init path
to handle CPUs that are initially offline.

The information on whether or not hybrid_max_perf_cpu was NULL before
it has been cleared is passed to hybrid_init_cpu_capacity_scaling(),
so full initialization of CPU capacity scaling can be skipped if it
has been carried out already.

No intentional functional impact.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/4616631.LvFx2qVVIh@rjwysocki.net
parent 59b723cd

drivers/cpufreq/intel_pstate.c

+18 −3
Original line number Diff line number Diff line
@@ -1034,7 +1034,7 @@ static void __hybrid_init_cpu_capacity_scaling(void) 
	hybrid_update_cpu_capacity_scaling();

}



static void hybrid_init_cpu_capacity_scaling(void)

static void hybrid_init_cpu_capacity_scaling(bool refresh)

{

	bool disable_itmt = false;
@@ -1045,7 +1045,7 @@ static void hybrid_init_cpu_capacity_scaling(void) 
	 * scaling has been enabled already and the driver is just changing the

	 * operation mode.

	 */

	if (hybrid_max_perf_cpu) {

	if (refresh) {

		__hybrid_init_cpu_capacity_scaling();

		goto unlock;

	}
@@ -1071,6 +1071,18 @@ static void hybrid_init_cpu_capacity_scaling(void) 
		sched_clear_itmt_support();

}



static bool hybrid_clear_max_perf_cpu(void)

{

	bool ret;



	guard(mutex)(&hybrid_capacity_lock);



	ret = !!hybrid_max_perf_cpu;

	hybrid_max_perf_cpu = NULL;



	return ret;

}



static void __intel_pstate_get_hwp_cap(struct cpudata *cpu)

{

	u64 cap;
@@ -3352,6 +3364,7 @@ static void intel_pstate_driver_cleanup(void) 


static int intel_pstate_register_driver(struct cpufreq_driver *driver)

{

	bool refresh_cpu_cap_scaling;

	int ret;



	if (driver == &intel_pstate)
@@ -3364,6 +3377,8 @@ static int intel_pstate_register_driver(struct cpufreq_driver *driver) 


	arch_set_max_freq_ratio(global.turbo_disabled);



	refresh_cpu_cap_scaling = hybrid_clear_max_perf_cpu();



	intel_pstate_driver = driver;

	ret = cpufreq_register_driver(intel_pstate_driver);

	if (ret) {
@@ -3373,7 +3388,7 @@ static int intel_pstate_register_driver(struct cpufreq_driver *driver) 


	global.min_perf_pct = min_perf_pct_min();



	hybrid_init_cpu_capacity_scaling();

	hybrid_init_cpu_capacity_scaling(refresh_cpu_cap_scaling);



	return 0;

}