Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit cb91fef1 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Rafael J. Wysocki
Browse files

thermal/intel_powerclamp: Convert to CPU hotplug state 



This is a conversation to the new hotplug state machine with
the difference that CPU_DEAD becomes CPU_PREDOWN.

At the same time it makes the handling of the two states symmetrical.
stop_power_clamp_worker() is called unconditionally and the controversial
error message is removed.

Finally, the hotplug state callbacks are removed after the powerclamping
is stopped to avoid a potential race.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
[pmladek@suse.com: Fixed the possible race in powerclamp_exit()]
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Signed-off-by: default avatarJacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 8d962ac7

drivers/thermal/intel_powerclamp.c

+36 −37
Original line number Diff line number Diff line
@@ -43,7 +43,6 @@ 
#include <linux/kernel.h>

#include <linux/delay.h>

#include <linux/kthread.h>

#include <linux/freezer.h>

#include <linux/cpu.h>

#include <linux/thermal.h>

#include <linux/slab.h>
@@ -530,8 +529,7 @@ static void start_power_clamp_worker(unsigned long cpu) 
	struct powerclamp_worker_data *w_data = per_cpu_ptr(worker_data, cpu);

	struct kthread_worker *worker;



	worker = kthread_create_worker_on_cpu(cpu, KTW_FREEZABLE,

					      "kidle_inject/%ld", cpu);

	worker = kthread_create_worker_on_cpu(cpu, 0, "kidle_inject/%ld", cpu);

	if (IS_ERR(worker))

		return;
@@ -622,42 +620,34 @@ static void end_power_clamp(void) 
	}

}



static int powerclamp_cpu_callback(struct notifier_block *nfb,

				unsigned long action, void *hcpu)

static int powerclamp_cpu_online(unsigned int cpu)

{

	unsigned long cpu = (unsigned long)hcpu;



	if (false == clamping)

		goto exit_ok;



	switch (action) {

	case CPU_ONLINE:

	if (clamping == false)

		return 0;

	start_power_clamp_worker(cpu);

	/* prefer BSP as controlling CPU */

	if (cpu == 0) {

		control_cpu = 0;

		smp_mb();

	}

		break;

	case CPU_DEAD:

		if (test_bit(cpu, cpu_clamping_mask)) {

			pr_err("cpu %lu dead but powerclamping thread is not\n",

				cpu);

			stop_power_clamp_worker(cpu);

		}

		if (cpu == control_cpu) {

			control_cpu = smp_processor_id();

			smp_mb();

		}

	return 0;

}



exit_ok:

	return NOTIFY_OK;

}

static int powerclamp_cpu_predown(unsigned int cpu)

{

	if (clamping == false)

		return 0;



static struct notifier_block powerclamp_cpu_notifier = {

	.notifier_call = powerclamp_cpu_callback,

};

	stop_power_clamp_worker(cpu);

	if (cpu != control_cpu)

		return 0;



	control_cpu = cpumask_first(cpu_online_mask);

	if (control_cpu == cpu)

		control_cpu = cpumask_next(cpu, cpu_online_mask);

	smp_mb();

	return 0;

}



static int powerclamp_get_max_state(struct thermal_cooling_device *cdev,

				 unsigned long *state)
@@ -788,6 +778,8 @@ static inline void powerclamp_create_debug_files(void) 
	debugfs_remove_recursive(debug_dir);

}



static enum cpuhp_state hp_state;



static int __init powerclamp_init(void)

{

	int retval;
@@ -805,7 +797,14 @@ static int __init powerclamp_init(void) 


	/* set default limit, maybe adjusted during runtime based on feedback */

	window_size = 2;

	register_hotcpu_notifier(&powerclamp_cpu_notifier);

	retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,

					   "thermal/intel_powerclamp:online",

					   powerclamp_cpu_online,

					   powerclamp_cpu_predown);

	if (retval < 0)

		goto exit_free;



	hp_state = retval;



	worker_data = alloc_percpu(struct powerclamp_worker_data);

	if (!worker_data) {
@@ -830,7 +829,7 @@ static int __init powerclamp_init(void) 
exit_free_thread:

	free_percpu(worker_data);

exit_unregister:

	unregister_hotcpu_notifier(&powerclamp_cpu_notifier);

	cpuhp_remove_state_nocalls(hp_state);

exit_free:

	kfree(cpu_clamping_mask);

	return retval;
@@ -839,8 +838,8 @@ module_init(powerclamp_init); 


static void __exit powerclamp_exit(void)

{

	unregister_hotcpu_notifier(&powerclamp_cpu_notifier);

	end_power_clamp();

	cpuhp_remove_state_nocalls(hp_state);

	free_percpu(worker_data);

	thermal_cooling_device_unregister(cooling_dev);

	kfree(cpu_clamping_mask);