Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq

* master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq:
  Move workqueue exports to where the functions are defined.
  [CPUFREQ] Misc cleanups in ondemand.
  [CPUFREQ] Make ondemand sampling per CPU and remove the mutex usage in sampling path.
  [CPUFREQ] Add queue_delayed_work_on() interface for workqueues.
  [CPUFREQ] Remove slowdown from ondemand sampling path.

1 files changed, 91 insertions, 169 deletions

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 693e540481b4..87299924e735 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -12,22 +12,11 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/smp.h>
 #include <linux/init.h>
-#include <linux/interrupt.h>
-#include <linux/ctype.h>
 #include <linux/cpufreq.h>
-#include <linux/sysctl.h>
-#include <linux/types.h>
-#include <linux/fs.h>
-#include <linux/sysfs.h>
 #include <linux/cpu.h>
-#include <linux/sched.h>
-#include <linux/kmod.h>
-#include <linux/workqueue.h>
 #include <linux/jiffies.h>
 #include <linux/kernel_stat.h>
-#include <linux/percpu.h>
 #include <linux/mutex.h>
 
 /*
@@ -56,16 +45,15 @@ static unsigned int def_sampling_rate;
 #define MIN_SAMPLING_RATE                       (def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
 #define MAX_SAMPLING_RATE                       (500 * def_sampling_rate)
 #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER    (1000)
-#define DEF_SAMPLING_DOWN_FACTOR                (1)
-#define MAX_SAMPLING_DOWN_FACTOR                (10)
 #define TRANSITION_LATENCY_LIMIT                (10 * 1000)
 
 static void do_dbs_timer(void *data);
 
 struct cpu_dbs_info_s {
+        cputime64_t prev_cpu_idle;
+        cputime64_t prev_cpu_wall;
         struct cpufreq_policy *cur_policy;
-        unsigned int prev_cpu_idle_up;
-        unsigned int prev_cpu_idle_down;
+        struct work_struct work;
         unsigned int enable;
 };
 static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
@@ -80,31 +68,32 @@ static unsigned int dbs_enable;	/* number of CPUs using this policy */
  * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
  * is recursive for the same process. -Venki
  */
-static DEFINE_MUTEX (dbs_mutex);
-static DECLARE_WORK     (dbs_work, do_dbs_timer, NULL);
+static DEFINE_MUTEX(dbs_mutex);
 
-static struct workqueue_struct *dbs_workq;
+static struct workqueue_struct  *kondemand_wq;
 
 struct dbs_tuners {
         unsigned int sampling_rate;
-        unsigned int sampling_down_factor;
         unsigned int up_threshold;
         unsigned int ignore_nice;
 };
 
 static struct dbs_tuners dbs_tuners_ins = {
         .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
-        .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
         .ignore_nice = 0,
 };
 
-static inline unsigned int get_cpu_idle_time(unsigned int cpu)
+static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
 {
-        return  kstat_cpu(cpu).cpustat.idle +
-                kstat_cpu(cpu).cpustat.iowait +
-                ( dbs_tuners_ins.ignore_nice ?
-                  kstat_cpu(cpu).cpustat.nice :
-                  0);
+        cputime64_t retval;
+
+        retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
+                        kstat_cpu(cpu).cpustat.iowait);
+
+        if (dbs_tuners_ins.ignore_nice)
+                retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
+
+        return retval;
 }
 
 /************************** sysfs interface ************************/
@@ -133,35 +122,15 @@ static ssize_t show_##file_name						\
         return sprintf(buf, "%u\n", dbs_tuners_ins.object);             \
 }
 show_one(sampling_rate, sampling_rate);
-show_one(sampling_down_factor, sampling_down_factor);
 show_one(up_threshold, up_threshold);
 show_one(ignore_nice_load, ignore_nice);
 
-static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
-                const char *buf, size_t count)
-{
-        unsigned int input;
-        int ret;
-        ret = sscanf (buf, "%u", &input);
-        if (ret != 1 )
-                return -EINVAL;
-
-        if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
-                return -EINVAL;
-
-        mutex_lock(&dbs_mutex);
-        dbs_tuners_ins.sampling_down_factor = input;
-        mutex_unlock(&dbs_mutex);
-
-        return count;
-}
-
 static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
                 const char *buf, size_t count)
 {
         unsigned int input;
         int ret;
-        ret = sscanf (buf, "%u", &input);
+        ret = sscanf(buf, "%u", &input);
 
         mutex_lock(&dbs_mutex);
         if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) {
@@ -180,7 +149,7 @@ static ssize_t store_up_threshold(struct cpufreq_policy *unused,
 {
         unsigned int input;
         int ret;
-        ret = sscanf (buf, "%u", &input);
+        ret = sscanf(buf, "%u", &input);
 
         mutex_lock(&dbs_mutex);
         if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
@@ -203,7 +172,7 @@ static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
 
         unsigned int j;
 
-        ret = sscanf (buf, "%u", &input);
+        ret = sscanf(buf, "%u", &input);
         if ( ret != 1 )
                 return -EINVAL;
 
@@ -217,12 +186,12 @@ static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
         }
         dbs_tuners_ins.ignore_nice = input;
 
-        /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */
+        /* we need to re-evaluate prev_cpu_idle */
         for_each_online_cpu(j) {
-                struct cpu_dbs_info_s *j_dbs_info;
-                j_dbs_info = &per_cpu(cpu_dbs_info, j);
-                j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j);
-                j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up;
+                struct cpu_dbs_info_s *dbs_info;
+                dbs_info = &per_cpu(cpu_dbs_info, j);
+                dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
+                dbs_info->prev_cpu_wall = get_jiffies_64();
         }
         mutex_unlock(&dbs_mutex);
 
@@ -234,7 +203,6 @@ static struct freq_attr _name = \
 __ATTR(_name, 0644, show_##_name, store_##_name)
 
 define_one_rw(sampling_rate);
-define_one_rw(sampling_down_factor);
 define_one_rw(up_threshold);
 define_one_rw(ignore_nice_load);
 
@@ -242,7 +210,6 @@ static struct attribute * dbs_attributes[] = {
         &sampling_rate_max.attr,
         &sampling_rate_min.attr,
         &sampling_rate.attr,
-        &sampling_down_factor.attr,
         &up_threshold.attr,
         &ignore_nice_load.attr,
         NULL
@@ -255,26 +222,27 @@ 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, up_idle_ticks, total_ticks;
-        unsigned int freq_next;
-        unsigned int freq_down_sampling_rate;
-        static int down_skip[NR_CPUS];
-        struct cpu_dbs_info_s *this_dbs_info;
+        unsigned int idle_ticks, total_ticks;
+        unsigned int load;
+        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;
 
         policy = this_dbs_info->cur_policy;
+        cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
+        total_ticks = (unsigned int) cputime64_sub(cur_jiffies,
+                        this_dbs_info->prev_cpu_wall);
+        this_dbs_info->prev_cpu_wall = cur_jiffies;
         /*
          * Every sampling_rate, we check, if current idle time is less
          * than 20% (default), then we try to increase frequency
-         * Every sampling_rate*sampling_down_factor, we look for a the lowest
+         * Every sampling_rate, we look for a the lowest
          * frequency which can sustain the load while keeping idle time over
          * 30%. If such a frequency exist, we try to decrease to this frequency.
          *
@@ -283,36 +251,26 @@ static void dbs_check_cpu(int cpu)
          * 5% (default) of current frequency
          */
 
-        /* Check for frequency increase */
+        /* Get Idle Time */
         idle_ticks = UINT_MAX;
         for_each_cpu_mask(j, policy->cpus) {
-                unsigned int tmp_idle_ticks, total_idle_ticks;
+                cputime64_t total_idle_ticks;
+                unsigned int tmp_idle_ticks;
                 struct cpu_dbs_info_s *j_dbs_info;
 
                 j_dbs_info = &per_cpu(cpu_dbs_info, j);
                 total_idle_ticks = get_cpu_idle_time(j);
-                tmp_idle_ticks = total_idle_ticks -
-                        j_dbs_info->prev_cpu_idle_up;
-                j_dbs_info->prev_cpu_idle_up = total_idle_ticks;
+                tmp_idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
+                                j_dbs_info->prev_cpu_idle);
+                j_dbs_info->prev_cpu_idle = total_idle_ticks;
 
                 if (tmp_idle_ticks < idle_ticks)
                         idle_ticks = tmp_idle_ticks;
         }
+        load = (100 * (total_ticks - idle_ticks)) / total_ticks;
 
-        /* Scale idle ticks by 100 and compare with up and down ticks */
-        idle_ticks *= 100;
-        up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) *
-                        usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
-
-        if (idle_ticks < up_idle_ticks) {
-                down_skip[cpu] = 0;
-                for_each_cpu_mask(j, policy->cpus) {
-                        struct cpu_dbs_info_s *j_dbs_info;
-
-                        j_dbs_info = &per_cpu(cpu_dbs_info, j);
-                        j_dbs_info->prev_cpu_idle_down =
-                                        j_dbs_info->prev_cpu_idle_up;
-                }
+        /* Check for frequency increase */
+        if (load > dbs_tuners_ins.up_threshold) {
                 /* if we are already at full speed then break out early */
                 if (policy->cur == policy->max)
                         return;
@@ -323,83 +281,49 @@ static void dbs_check_cpu(int cpu)
         }
 
         /* Check for frequency decrease */
-        down_skip[cpu]++;
-        if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor)
-                return;
-
-        idle_ticks = UINT_MAX;
-        for_each_cpu_mask(j, policy->cpus) {
-                unsigned int tmp_idle_ticks, total_idle_ticks;
-                struct cpu_dbs_info_s *j_dbs_info;
-
-                j_dbs_info = &per_cpu(cpu_dbs_info, j);
-                /* Check for frequency decrease */
-                total_idle_ticks = j_dbs_info->prev_cpu_idle_up;
-                tmp_idle_ticks = total_idle_ticks -
-                        j_dbs_info->prev_cpu_idle_down;
-                j_dbs_info->prev_cpu_idle_down = total_idle_ticks;
-
-                if (tmp_idle_ticks < idle_ticks)
-                        idle_ticks = tmp_idle_ticks;
-        }
-
-        down_skip[cpu] = 0;
         /* if we cannot reduce the frequency anymore, break out early */
         if (policy->cur == policy->min)
                 return;
 
-        /* Compute how many ticks there are between two measurements */
-        freq_down_sampling_rate = dbs_tuners_ins.sampling_rate *
-                dbs_tuners_ins.sampling_down_factor;
-        total_ticks = usecs_to_jiffies(freq_down_sampling_rate);
-
         /*
          * The optimal frequency is the frequency that is the lowest that
          * can support the current CPU usage without triggering the up
          * policy. To be safe, we focus 10 points under the threshold.
          */
-        freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks;
-        freq_next = (freq_next * policy->cur) /
+        if (load < (dbs_tuners_ins.up_threshold - 10)) {
+                unsigned int freq_next;
+                freq_next = (policy->cur * load) /
                         (dbs_tuners_ins.up_threshold - 10);
 
-        if (freq_next < policy->min)
-                freq_next = policy->min;
-
-        if (freq_next <= ((policy->cur * 95) / 100))
                 __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L);
+        }
 }
 
 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,
-                           usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
-        mutex_unlock(&dbs_mutex);
-        unlock_cpu_hotplug();
+        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));
 }
 
-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,
-                           usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
+        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,
@@ -413,8 +337,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 
         switch (event) {
         case CPUFREQ_GOV_START:
-                if ((!cpu_online(cpu)) ||
-                    (!policy->cur))
+                if ((!cpu_online(cpu)) || (!policy->cur))
                         return -EINVAL;
 
                 if (policy->cpuinfo.transition_latency >
@@ -427,18 +350,26 @@ 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);
                         j_dbs_info->cur_policy = policy;
 
-                        j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j);
-                        j_dbs_info->prev_cpu_idle_down
-                                = j_dbs_info->prev_cpu_idle_up;
+                        j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
+                        j_dbs_info->prev_cpu_wall = get_jiffies_64();
                 }
                 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
@@ -457,23 +388,20 @@ 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);
 
@@ -483,13 +411,13 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                 lock_cpu_hotplug();
                 mutex_lock(&dbs_mutex);
                 if (policy->max < this_dbs_info->cur_policy->cur)
-                        __cpufreq_driver_target(
-                                        this_dbs_info->cur_policy,
-                                        policy->max, CPUFREQ_RELATION_H);
+                        __cpufreq_driver_target(this_dbs_info->cur_policy,
+                                                policy->max,
+                                                CPUFREQ_RELATION_H);
                 else if (policy->min > this_dbs_info->cur_policy->cur)
-                        __cpufreq_driver_target(
-                                        this_dbs_info->cur_policy,
-                                        policy->min, CPUFREQ_RELATION_L);
+                        __cpufreq_driver_target(this_dbs_info->cur_policy,
+                                                policy->min,
+                                                CPUFREQ_RELATION_L);
                 mutex_unlock(&dbs_mutex);
                 unlock_cpu_hotplug();
                 break;
@@ -498,9 +426,9 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 }
 
 static struct cpufreq_governor cpufreq_gov_dbs = {
-        .name           = "ondemand",
-        .governor       = cpufreq_governor_dbs,
-        .owner          = THIS_MODULE,
+        .name = "ondemand",
+        .governor = cpufreq_governor_dbs,
+        .owner = THIS_MODULE,
 };
 
 static int __init cpufreq_gov_dbs_init(void)
@@ -510,21 +438,15 @@ 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);
 }
 
 
-MODULE_AUTHOR ("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
-MODULE_DESCRIPTION ("'cpufreq_ondemand' - A dynamic cpufreq governor for "
-                "Low Latency Frequency Transition capable processors");
-MODULE_LICENSE ("GPL");
+MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
+MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
+MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
+                   "Low Latency Frequency Transition capable processors");
+MODULE_LICENSE("GPL");
 
 module_init(cpufreq_gov_dbs_init);
 module_exit(cpufreq_gov_dbs_exit);