Merge with rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git

[karo-tx-linux.git] / drivers / cpufreq / cpufreq_ondemand.c

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index c1fc9c62bb51d0c1d2620f522d7c6ebbb0f432bc..9ee9411f186f9b8738f4a7320991f058576733d7 100644 (file)
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -27,6 +27,7 @@
 #include <linux/jiffies.h>
 #include <linux/kernel_stat.h>
 #include <linux/percpu.h>
+#include <linux/mutex.h>
 
 /*
  * dbs is used in this file as a shortform for demandbased switching
@@ -48,7 +49,10 @@
  * All times here are in uS.
  */
 static unsigned int                            def_sampling_rate;
-#define MIN_SAMPLING_RATE                      (def_sampling_rate / 2)
+#define MIN_SAMPLING_RATE_RATIO                        (2)
+/* for correct statistics, we need at least 10 ticks between each measure */
+#define MIN_STAT_SAMPLING_RATE                 (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
+#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)
@@ -67,7 +71,7 @@ static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
 
 static unsigned int dbs_enable;        /* number of CPUs using this policy */
 
-static DECLARE_MUTEX   (dbs_sem);
+static DEFINE_MUTEX    (dbs_mutex);
 static DECLARE_WORK    (dbs_work, do_dbs_timer, NULL);
 
 struct dbs_tuners {
@@ -86,7 +90,7 @@ static inline unsigned int get_cpu_idle_time(unsigned int cpu)
 {
        return  kstat_cpu(cpu).cpustat.idle +
                kstat_cpu(cpu).cpustat.iowait +
-               ( !dbs_tuners_ins.ignore_nice ? 
+               ( dbs_tuners_ins.ignore_nice ?
                  kstat_cpu(cpu).cpustat.nice :
                  0);
 }
@@ -119,7 +123,7 @@ static ssize_t show_##file_name                                             \
 show_one(sampling_rate, sampling_rate);
 show_one(sampling_down_factor, sampling_down_factor);
 show_one(up_threshold, up_threshold);
-show_one(ignore_nice, ignore_nice);
+show_one(ignore_nice_load, ignore_nice);
 
 static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, 
                const char *buf, size_t count)
@@ -133,9 +137,9 @@ static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
        if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
                return -EINVAL;
 
-       down(&dbs_sem);
+       mutex_lock(&dbs_mutex);
        dbs_tuners_ins.sampling_down_factor = input;
-       up(&dbs_sem);
+       mutex_unlock(&dbs_mutex);
 
        return count;
 }
@@ -147,14 +151,14 @@ static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
        int ret;
        ret = sscanf (buf, "%u", &input);
 
-       down(&dbs_sem);
+       mutex_lock(&dbs_mutex);
        if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) {
-               up(&dbs_sem);
+               mutex_unlock(&dbs_mutex);
                return -EINVAL;
        }
 
        dbs_tuners_ins.sampling_rate = input;
-       up(&dbs_sem);
+       mutex_unlock(&dbs_mutex);
 
        return count;
 }
@@ -166,20 +170,20 @@ static ssize_t store_up_threshold(struct cpufreq_policy *unused,
        int ret;
        ret = sscanf (buf, "%u", &input);
 
-       down(&dbs_sem);
+       mutex_lock(&dbs_mutex);
        if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || 
                        input < MIN_FREQUENCY_UP_THRESHOLD) {
-               up(&dbs_sem);
+               mutex_unlock(&dbs_mutex);
                return -EINVAL;
        }
 
        dbs_tuners_ins.up_threshold = input;
-       up(&dbs_sem);
+       mutex_unlock(&dbs_mutex);
 
        return count;
 }
 
-static ssize_t store_ignore_nice(struct cpufreq_policy *policy,
+static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
                const char *buf, size_t count)
 {
        unsigned int input;
@@ -194,9 +198,9 @@ static ssize_t store_ignore_nice(struct cpufreq_policy *policy,
        if ( input > 1 )
                input = 1;
        
-       down(&dbs_sem);
+       mutex_lock(&dbs_mutex);
        if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */
-               up(&dbs_sem);
+               mutex_unlock(&dbs_mutex);
                return count;
        }
        dbs_tuners_ins.ignore_nice = input;
@@ -208,7 +212,7 @@ static ssize_t store_ignore_nice(struct cpufreq_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;
        }
-       up(&dbs_sem);
+       mutex_unlock(&dbs_mutex);
 
        return count;
 }
@@ -220,7 +224,7 @@ __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);
+define_one_rw(ignore_nice_load);
 
 static struct attribute * dbs_attributes[] = {
        &sampling_rate_max.attr,
@@ -228,7 +232,7 @@ static struct attribute * dbs_attributes[] = {
        &sampling_rate.attr,
        &sampling_down_factor.attr,
        &up_threshold.attr,
-       &ignore_nice.attr,
+       &ignore_nice_load.attr,
        NULL
 };
 
@@ -353,12 +357,12 @@ static void dbs_check_cpu(int cpu)
 static void do_dbs_timer(void *data)
 { 
        int i;
-       down(&dbs_sem);
+       mutex_lock(&dbs_mutex);
        for_each_online_cpu(i)
                dbs_check_cpu(i);
        schedule_delayed_work(&dbs_work, 
                        usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
-       up(&dbs_sem);
+       mutex_unlock(&dbs_mutex);
 } 
 
 static inline void dbs_timer_init(void)
@@ -396,7 +400,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                if (this_dbs_info->enable) /* Already enabled */
                        break;
                 
-               down(&dbs_sem);
+               mutex_lock(&dbs_mutex);
                for_each_cpu_mask(j, policy->cpus) {
                        struct cpu_dbs_info_s *j_dbs_info;
                        j_dbs_info = &per_cpu(cpu_dbs_info, j);
@@ -416,24 +420,27 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                if (dbs_enable == 1) {
                        unsigned int latency;
                        /* policy latency is in nS. Convert it to uS first */
+                       latency = policy->cpuinfo.transition_latency / 1000;
+                       if (latency == 0)
+                               latency = 1;
 
-                       latency = policy->cpuinfo.transition_latency;
-                       if (latency < 1000)
-                               latency = 1000;
-
-                       def_sampling_rate = (latency / 1000) *
+                       def_sampling_rate = latency *
                                        DEF_SAMPLING_RATE_LATENCY_MULTIPLIER;
+
+                       if (def_sampling_rate < MIN_STAT_SAMPLING_RATE)
+                               def_sampling_rate = MIN_STAT_SAMPLING_RATE;
+
                        dbs_tuners_ins.sampling_rate = def_sampling_rate;
                        dbs_tuners_ins.ignore_nice = 0;
 
                        dbs_timer_init();
                }
                
-               up(&dbs_sem);
+               mutex_unlock(&dbs_mutex);
                break;
 
        case CPUFREQ_GOV_STOP:
-               down(&dbs_sem);
+               mutex_lock(&dbs_mutex);
                this_dbs_info->enable = 0;
                sysfs_remove_group(&policy->kobj, &dbs_attr_group);
                dbs_enable--;
@@ -444,12 +451,12 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                if (dbs_enable == 0) 
                        dbs_timer_exit();
                
-               up(&dbs_sem);
+               mutex_unlock(&dbs_mutex);
 
                break;
 
        case CPUFREQ_GOV_LIMITS:
-               down(&dbs_sem);
+               mutex_lock(&dbs_mutex);
                if (policy->max < this_dbs_info->cur_policy->cur)
                        __cpufreq_driver_target(
                                        this_dbs_info->cur_policy,
@@ -458,7 +465,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                        __cpufreq_driver_target(
                                        this_dbs_info->cur_policy,
                                        policy->min, CPUFREQ_RELATION_L);
-               up(&dbs_sem);
+               mutex_unlock(&dbs_mutex);
                break;
        }
        return 0;