* This must be called with dbs_data->mutex held, otherwise traversing
* policy_dbs_list isn't safe.
*/
-ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
+ssize_t store_sampling_rate(struct gov_attr_set *attr_set, const char *buf,
size_t count)
{
+ struct dbs_data *dbs_data = to_dbs_data(attr_set);
struct policy_dbs_info *policy_dbs;
unsigned int rate;
int ret;
* We are operating under dbs_data->mutex and so the list and its
* entries can't be freed concurrently.
*/
- list_for_each_entry(policy_dbs, &dbs_data->policy_dbs_list, list) {
+ list_for_each_entry(policy_dbs, &attr_set->policy_list, list) {
mutex_lock(&policy_dbs->timer_mutex);
/*
* On 32-bit architectures this may race with the
{
struct policy_dbs_info *policy_dbs;
- list_for_each_entry(policy_dbs, &dbs_data->policy_dbs_list, list) {
+ list_for_each_entry(policy_dbs, &dbs_data->attr_set.policy_list, list) {
unsigned int j;
for_each_cpu(j, policy_dbs->policy->cpus) {
struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
- j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_cpu_wall,
+ j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time,
dbs_data->io_is_busy);
if (dbs_data->ignore_nice_load)
j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
}
EXPORT_SYMBOL_GPL(gov_update_cpu_data);
-static inline struct dbs_data *to_dbs_data(struct kobject *kobj)
-{
- return container_of(kobj, struct dbs_data, kobj);
-}
-
-static inline struct governor_attr *to_gov_attr(struct attribute *attr)
-{
- return container_of(attr, struct governor_attr, attr);
-}
-
-static ssize_t governor_show(struct kobject *kobj, struct attribute *attr,
- char *buf)
-{
- struct dbs_data *dbs_data = to_dbs_data(kobj);
- struct governor_attr *gattr = to_gov_attr(attr);
-
- return gattr->show(dbs_data, buf);
-}
-
-static ssize_t governor_store(struct kobject *kobj, struct attribute *attr,
- const char *buf, size_t count)
-{
- struct dbs_data *dbs_data = to_dbs_data(kobj);
- struct governor_attr *gattr = to_gov_attr(attr);
- int ret = -EBUSY;
-
- mutex_lock(&dbs_data->mutex);
-
- if (dbs_data->usage_count)
- ret = gattr->store(dbs_data, buf, count);
-
- mutex_unlock(&dbs_data->mutex);
-
- return ret;
-}
-
-/*
- * Sysfs Ops for accessing governor attributes.
- *
- * All show/store invocations for governor specific sysfs attributes, will first
- * call the below show/store callbacks and the attribute specific callback will
- * be called from within it.
- */
-static const struct sysfs_ops governor_sysfs_ops = {
- .show = governor_show,
- .store = governor_store,
-};
-
unsigned int dbs_update(struct cpufreq_policy *policy)
{
struct policy_dbs_info *policy_dbs = policy->governor_data;
/* Get Absolute Load */
for_each_cpu(j, policy->cpus) {
struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
- u64 cur_wall_time, cur_idle_time;
- unsigned int idle_time, wall_time;
+ u64 update_time, cur_idle_time;
+ unsigned int idle_time, time_elapsed;
unsigned int load;
- cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy);
+ cur_idle_time = get_cpu_idle_time(j, &update_time, io_busy);
- wall_time = cur_wall_time - j_cdbs->prev_cpu_wall;
- j_cdbs->prev_cpu_wall = cur_wall_time;
+ time_elapsed = update_time - j_cdbs->prev_update_time;
+ j_cdbs->prev_update_time = update_time;
idle_time = cur_idle_time - j_cdbs->prev_cpu_idle;
j_cdbs->prev_cpu_idle = cur_idle_time;
j_cdbs->prev_cpu_nice = cur_nice;
}
- if (unlikely(!wall_time || wall_time < idle_time))
- continue;
-
- /*
- * If the CPU had gone completely idle, and a task just woke up
- * on this CPU now, it would be unfair to calculate 'load' the
- * usual way for this elapsed time-window, because it will show
- * near-zero load, irrespective of how CPU intensive that task
- * actually is. This is undesirable for latency-sensitive bursty
- * workloads.
- *
- * To avoid this, we reuse the 'load' from the previous
- * time-window and give this task a chance to start with a
- * reasonably high CPU frequency. (However, we shouldn't over-do
- * this copy, lest we get stuck at a high load (high frequency)
- * for too long, even when the current system load has actually
- * dropped down. So we perform the copy only once, upon the
- * first wake-up from idle.)
- *
- * Detecting this situation is easy: the governor's utilization
- * update handler would not have run during CPU-idle periods.
- * Hence, an unusually large 'wall_time' (as compared to the
- * sampling rate) indicates this scenario.
- *
- * prev_load can be zero in two cases and we must recalculate it
- * for both cases:
- * - during long idle intervals
- * - explicitly set to zero
- */
- if (unlikely(wall_time > (2 * sampling_rate) &&
- j_cdbs->prev_load)) {
+ if (unlikely(!time_elapsed)) {
+ /*
+ * That can only happen when this function is called
+ * twice in a row with a very short interval between the
+ * calls, so the previous load value can be used then.
+ */
load = j_cdbs->prev_load;
-
+ } else if (unlikely(time_elapsed > 2 * sampling_rate &&
+ j_cdbs->prev_load)) {
/*
- * Perform a destructive copy, to ensure that we copy
- * the previous load only once, upon the first wake-up
- * from idle.
+ * If the CPU had gone completely idle and a task has
+ * just woken up on this CPU now, it would be unfair to
+ * calculate 'load' the usual way for this elapsed
+ * time-window, because it would show near-zero load,
+ * irrespective of how CPU intensive that task actually
+ * was. This is undesirable for latency-sensitive bursty
+ * workloads.
+ *
+ * To avoid this, reuse the 'load' from the previous
+ * time-window and give this task a chance to start with
+ * a reasonably high CPU frequency. However, that
+ * shouldn't be over-done, lest we get stuck at a high
+ * load (high frequency) for too long, even when the
+ * current system load has actually dropped down, so
+ * clear prev_load to guarantee that the load will be
+ * computed again next time.
+ *
+ * Detecting this situation is easy: the governor's
+ * utilization update handler would not have run during
+ * CPU-idle periods. Hence, an unusually large
+ * 'time_elapsed' (as compared to the sampling rate)
+ * indicates this scenario.
*/
+ load = j_cdbs->prev_load;
j_cdbs->prev_load = 0;
} else {
- load = 100 * (wall_time - idle_time) / wall_time;
+ if (time_elapsed >= idle_time) {
+ load = 100 * (time_elapsed - idle_time) / time_elapsed;
+ } else {
+ /*
+ * That can happen if idle_time is returned by
+ * get_cpu_idle_time_jiffy(). In that case
+ * idle_time is roughly equal to the difference
+ * between time_elapsed and "busy time" obtained
+ * from CPU statistics. Then, the "busy time"
+ * can end up being greater than time_elapsed
+ * (for example, if jiffies_64 and the CPU
+ * statistics are updated by different CPUs),
+ * so idle_time may in fact be negative. That
+ * means, though, that the CPU was busy all
+ * the time (on the rough average) during the
+ * last sampling interval and 100 can be
+ * returned as the load.
+ */
+ load = (int)idle_time < 0 ? 100 : 0;
+ }
j_cdbs->prev_load = load;
}
}
EXPORT_SYMBOL_GPL(dbs_update);
-static void gov_set_update_util(struct policy_dbs_info *policy_dbs,
- unsigned int delay_us)
-{
- struct cpufreq_policy *policy = policy_dbs->policy;
- int cpu;
-
- gov_update_sample_delay(policy_dbs, delay_us);
- policy_dbs->last_sample_time = 0;
-
- for_each_cpu(cpu, policy->cpus) {
- struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu);
-
- cpufreq_set_update_util_data(cpu, &cdbs->update_util);
- }
-}
-
-static inline void gov_clear_update_util(struct cpufreq_policy *policy)
-{
- int i;
-
- for_each_cpu(i, policy->cpus)
- cpufreq_set_update_util_data(i, NULL);
-
- synchronize_sched();
-}
-
-static void gov_cancel_work(struct cpufreq_policy *policy)
-{
- struct policy_dbs_info *policy_dbs = policy->governor_data;
-
- gov_clear_update_util(policy_dbs->policy);
- irq_work_sync(&policy_dbs->irq_work);
- cancel_work_sync(&policy_dbs->work);
- atomic_set(&policy_dbs->work_count, 0);
- policy_dbs->work_in_progress = false;
-}
-
static void dbs_work_handler(struct work_struct *work)
{
struct policy_dbs_info *policy_dbs;
irq_work_queue(&policy_dbs->irq_work);
}
+static void gov_set_update_util(struct policy_dbs_info *policy_dbs,
+ unsigned int delay_us)
+{
+ struct cpufreq_policy *policy = policy_dbs->policy;
+ int cpu;
+
+ gov_update_sample_delay(policy_dbs, delay_us);
+ policy_dbs->last_sample_time = 0;
+
+ for_each_cpu(cpu, policy->cpus) {
+ struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu);
+
+ cpufreq_add_update_util_hook(cpu, &cdbs->update_util,
+ dbs_update_util_handler);
+ }
+}
+
+static inline void gov_clear_update_util(struct cpufreq_policy *policy)
+{
+ int i;
+
+ for_each_cpu(i, policy->cpus)
+ cpufreq_remove_update_util_hook(i);
+
+ synchronize_sched();
+}
+
+static void gov_cancel_work(struct cpufreq_policy *policy)
+{
+ struct policy_dbs_info *policy_dbs = policy->governor_data;
+
+ gov_clear_update_util(policy_dbs->policy);
+ irq_work_sync(&policy_dbs->irq_work);
+ cancel_work_sync(&policy_dbs->work);
+ atomic_set(&policy_dbs->work_count, 0);
+ policy_dbs->work_in_progress = false;
+}
+
static struct policy_dbs_info *alloc_policy_dbs_info(struct cpufreq_policy *policy,
struct dbs_governor *gov)
{
struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
j_cdbs->policy_dbs = policy_dbs;
- j_cdbs->update_util.func = dbs_update_util_handler;
}
return policy_dbs;
}
policy_dbs->dbs_data = dbs_data;
policy->governor_data = policy_dbs;
- mutex_lock(&dbs_data->mutex);
- dbs_data->usage_count++;
- list_add(&policy_dbs->list, &dbs_data->policy_dbs_list);
- mutex_unlock(&dbs_data->mutex);
+ gov_attr_set_get(&dbs_data->attr_set, &policy_dbs->list);
goto out;
}
goto free_policy_dbs_info;
}
- INIT_LIST_HEAD(&dbs_data->policy_dbs_list);
- mutex_init(&dbs_data->mutex);
+ gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list);
ret = gov->init(dbs_data, !policy->governor->initialized);
if (ret)
if (!have_governor_per_policy())
gov->gdbs_data = dbs_data;
- policy->governor_data = policy_dbs;
-
policy_dbs->dbs_data = dbs_data;
- dbs_data->usage_count = 1;
- list_add(&policy_dbs->list, &dbs_data->policy_dbs_list);
+ policy->governor_data = policy_dbs;
gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
- ret = kobject_init_and_add(&dbs_data->kobj, &gov->kobj_type,
+ ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type,
get_governor_parent_kobj(policy),
"%s", gov->gov.name);
if (!ret)
struct dbs_governor *gov = dbs_governor_of(policy);
struct policy_dbs_info *policy_dbs = policy->governor_data;
struct dbs_data *dbs_data = policy_dbs->dbs_data;
- int count;
+ unsigned int count;
/* Protect gov->gdbs_data against concurrent updates. */
mutex_lock(&gov_dbs_data_mutex);
- mutex_lock(&dbs_data->mutex);
- list_del(&policy_dbs->list);
- count = --dbs_data->usage_count;
- mutex_unlock(&dbs_data->mutex);
+ count = gov_attr_set_put(&dbs_data->attr_set, &policy_dbs->list);
- if (!count) {
- kobject_put(&dbs_data->kobj);
-
- policy->governor_data = NULL;
+ policy->governor_data = NULL;
+ if (!count) {
if (!have_governor_per_policy())
gov->gdbs_data = NULL;
gov->exit(dbs_data, policy->governor->initialized == 1);
- mutex_destroy(&dbs_data->mutex);
kfree(dbs_data);
- } else {
- policy->governor_data = NULL;
}
free_policy_dbs_info(policy_dbs, gov);
for_each_cpu(j, policy->cpus) {
struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
- unsigned int prev_load;
- j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_cpu_wall, io_busy);
-
- prev_load = j_cdbs->prev_cpu_wall - j_cdbs->prev_cpu_idle;
- j_cdbs->prev_load = 100 * prev_load / (unsigned int)j_cdbs->prev_cpu_wall;
+ j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time, io_busy);
+ /*
+ * Make the first invocation of dbs_update() compute the load.
+ */
+ j_cdbs->prev_load = 0;
if (ignore_nice)
j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
projects / cascardo / linux.git / blobdiff