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Commit 2f8a835c authored by Venkatesh Pallipadi's avatar Venkatesh Pallipadi Committed by Dave Jones
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[CPUFREQ] Make ondemand sampling per CPU and remove the mutex usage in sampling path. 



Make ondemand sampling per CPU and remove the mutex usage in sampling path.

Signed-off-by: default avatarAlexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent 7a6bc1cd

drivers/cpufreq/cpufreq_ondemand.c

+32 −40
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ struct cpu_dbs_info_s { 
	cputime64_t prev_cpu_idle;

	cputime64_t prev_cpu_wall;

	struct cpufreq_policy *cur_policy;

 	struct work_struct work;

	unsigned int enable;

};

static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
@@ -81,7 +82,7 @@ static unsigned int dbs_enable; /* number of CPUs using this policy */ 
static DEFINE_MUTEX (dbs_mutex);

static DECLARE_WORK	(dbs_work, do_dbs_timer, NULL);



static struct workqueue_struct *dbs_workq;

static struct workqueue_struct	*kondemand_wq;



struct dbs_tuners {

	unsigned int sampling_rate;
@@ -233,17 +234,15 @@ static struct attribute_group dbs_attr_group = { 


/************************** sysfs end ************************/



static void dbs_check_cpu(int cpu)

static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)

{

	unsigned int idle_ticks, total_ticks;

	unsigned int load;

	struct cpu_dbs_info_s *this_dbs_info;

	cputime64_t cur_jiffies;



	struct cpufreq_policy *policy;

	unsigned int j;



	this_dbs_info = &per_cpu(cpu_dbs_info, cpu);

	if (!this_dbs_info->enable)

		return;
@@ -314,35 +313,29 @@ static void dbs_check_cpu(int cpu) 


static void do_dbs_timer(void *data)

{

	int i;

	lock_cpu_hotplug();

	mutex_lock(&dbs_mutex);

	for_each_online_cpu(i)

		dbs_check_cpu(i);

	queue_delayed_work(dbs_workq, &dbs_work,

	unsigned int cpu = smp_processor_id();

	struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);



	dbs_check_cpu(dbs_info);

	queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work,

			usecs_to_jiffies(dbs_tuners_ins.sampling_rate));

	mutex_unlock(&dbs_mutex);

	unlock_cpu_hotplug();

}



static inline void dbs_timer_init(void)

static inline void dbs_timer_init(unsigned int cpu)

{

	INIT_WORK(&dbs_work, do_dbs_timer, NULL);

	if (!dbs_workq)

		dbs_workq = create_singlethread_workqueue("ondemand");

	if (!dbs_workq) {

		printk(KERN_ERR "ondemand: Cannot initialize kernel thread\n");

		return;

	}

	queue_delayed_work(dbs_workq, &dbs_work,

	struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);



	INIT_WORK(&dbs_info->work, do_dbs_timer, 0);

	queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work,

			usecs_to_jiffies(dbs_tuners_ins.sampling_rate));

	return;

}



static inline void dbs_timer_exit(void)

static inline void dbs_timer_exit(unsigned int cpu)

{

	if (dbs_workq)

		cancel_rearming_delayed_workqueue(dbs_workq, &dbs_work);

	struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);



	cancel_rearming_delayed_workqueue(kondemand_wq, &dbs_info->work);

}



static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
@@ -370,6 +363,16 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, 
			break;



		mutex_lock(&dbs_mutex);

		dbs_enable++;

		if (dbs_enable == 1) {

			kondemand_wq = create_workqueue("kondemand");

			if (!kondemand_wq) {

				printk(KERN_ERR "Creation of kondemand failed\n");

				dbs_enable--;

				mutex_unlock(&dbs_mutex);

				return -ENOSPC;

			}

		}

		for_each_cpu_mask(j, policy->cpus) {

			struct cpu_dbs_info_s *j_dbs_info;

			j_dbs_info = &per_cpu(cpu_dbs_info, j);
@@ -380,7 +383,6 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, 
		}

		this_dbs_info->enable = 1;

		sysfs_create_group(&policy->kobj, &dbs_attr_group);

		dbs_enable++;

		/*

		 * Start the timerschedule work, when this governor

		 * is used for first time
@@ -399,23 +401,20 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, 
				def_sampling_rate = MIN_STAT_SAMPLING_RATE;



			dbs_tuners_ins.sampling_rate = def_sampling_rate;

			dbs_timer_init();

		}

		dbs_timer_init(policy->cpu);



		mutex_unlock(&dbs_mutex);

		break;



	case CPUFREQ_GOV_STOP:

		mutex_lock(&dbs_mutex);

		dbs_timer_exit(policy->cpu);

		this_dbs_info->enable = 0;

		sysfs_remove_group(&policy->kobj, &dbs_attr_group);

		dbs_enable--;

		/*

		 * Stop the timerschedule work, when this governor

		 * is used for first time

		 */

		if (dbs_enable == 0)

			dbs_timer_exit();

			destroy_workqueue(kondemand_wq);



		mutex_unlock(&dbs_mutex);
@@ -452,13 +451,6 @@ static int __init cpufreq_gov_dbs_init(void) 


static void __exit cpufreq_gov_dbs_exit(void)

{

	/* Make sure that the scheduled work is indeed not running.

	   Assumes the timer has been cancelled first. */

	if (dbs_workq) {

		flush_workqueue(dbs_workq);

		destroy_workqueue(dbs_workq);

	}



	cpufreq_unregister_governor(&cpufreq_gov_dbs);

}