diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 999e1f6addf9e1352fa29da675af3c8e893baef0..2d61eae5cc5da3f0d9d35b8beb4cf019457fcf36 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -158,47 +158,53 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
}
EXPORT_SYMBOL_GPL(dbs_check_cpu);
-static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data,
- unsigned int delay)
+void gov_add_timers(struct cpufreq_policy *policy, unsigned int delay)
{
- struct cpu_dbs_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
-
- mod_delayed_work_on(cpu, system_wq, &cdbs->dwork, delay);
-}
-
-void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
- unsigned int delay, bool all_cpus)
-{
- int i;
+ struct dbs_data *dbs_data = policy->governor_data;
+ struct cpu_dbs_info *cdbs;
+ int cpu;
- if (!all_cpus) {
- /*
- * Use raw_smp_processor_id() to avoid preemptible warnings.
- * We know that this is only called with all_cpus == false from
- * works that have been queued with *_work_on() functions and
- * those works are canceled during CPU_DOWN_PREPARE so they
- * can't possibly run on any other CPU.
- */
- __gov_queue_work(raw_smp_processor_id(), dbs_data, delay);
- } else {
- for_each_cpu(i, policy->cpus)
- __gov_queue_work(i, dbs_data, delay);
+ for_each_cpu(cpu, policy->cpus) {
+ cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+ cdbs->timer.expires = jiffies + delay;
+ add_timer_on(&cdbs->timer, cpu);
}
}
-EXPORT_SYMBOL_GPL(gov_queue_work);
+EXPORT_SYMBOL_GPL(gov_add_timers);
-static inline void gov_cancel_work(struct dbs_data *dbs_data,
- struct cpufreq_policy *policy)
+static inline void gov_cancel_timers(struct cpufreq_policy *policy)
{
+ struct dbs_data *dbs_data = policy->governor_data;
struct cpu_dbs_info *cdbs;
int i;
for_each_cpu(i, policy->cpus) {
cdbs = dbs_data->cdata->get_cpu_cdbs(i);
- cancel_delayed_work_sync(&cdbs->dwork);
+ del_timer_sync(&cdbs->timer);
}
}
+void gov_cancel_work(struct cpu_common_dbs_info *shared)
+{
+ unsigned long flags;
+
+ /*
+ * No work will be queued from timer handlers after skip_work is
+ * updated. And so we can safely cancel the work first and then the
+ * timers.
+ */
+ spin_lock_irqsave(&shared->timer_lock, flags);
+ shared->skip_work++;
+ spin_unlock_irqrestore(&shared->timer_lock, flags);
+
+ cancel_work_sync(&shared->work);
+
+ gov_cancel_timers(shared->policy);
+
+ shared->skip_work = 0;
+}
+EXPORT_SYMBOL_GPL(gov_cancel_work);
+
/* Will return if we need to evaluate cpu load again or not */
static bool need_load_eval(struct cpu_common_dbs_info *shared,
unsigned int sampling_rate)
@@ -217,29 +223,22 @@ static bool need_load_eval(struct cpu_common_dbs_info *shared,
return true;
}
-static void dbs_timer(struct work_struct *work)
+static void dbs_work_handler(struct work_struct *work)
{
- struct cpu_dbs_info *cdbs = container_of(work, struct cpu_dbs_info,
- dwork.work);
- struct cpu_common_dbs_info *shared = cdbs->shared;
+ struct cpu_common_dbs_info *shared = container_of(work, struct
+ cpu_common_dbs_info, work);
struct cpufreq_policy *policy;
struct dbs_data *dbs_data;
unsigned int sampling_rate, delay;
- bool modify_all = true;
-
- mutex_lock(&shared->timer_mutex);
+ unsigned long flags;
+ bool eval_load;
policy = shared->policy;
-
- /*
- * Governor might already be disabled and there is no point continuing
- * with the work-handler.
- */
- if (!policy)
- goto unlock;
-
dbs_data = policy->governor_data;
+ /* Kill all timers */
+ gov_cancel_timers(policy);
+
if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
@@ -250,14 +249,43 @@ static void dbs_timer(struct work_struct *work)
sampling_rate = od_tuners->sampling_rate;
}
- if (!need_load_eval(cdbs->shared, sampling_rate))
- modify_all = false;
+ eval_load = need_load_eval(shared, sampling_rate);
- delay = dbs_data->cdata->gov_dbs_timer(policy, modify_all);
- gov_queue_work(dbs_data, policy, delay, modify_all);
-
-unlock:
+ /*
+ * Make sure cpufreq_governor_limits() isn't evaluating load in
+ * parallel.
+ */
+ mutex_lock(&shared->timer_mutex);
+ delay = dbs_data->cdata->gov_dbs_timer(policy, eval_load);
mutex_unlock(&shared->timer_mutex);
+
+ spin_lock_irqsave(&shared->timer_lock, flags);
+ shared->skip_work--;
+ spin_unlock_irqrestore(&shared->timer_lock, flags);
+
+ gov_add_timers(policy, delay);
+}
+
+static void dbs_timer_handler(unsigned long data)
+{
+ struct cpu_dbs_info *cdbs = (struct cpu_dbs_info *)data;
+ struct cpu_common_dbs_info *shared = cdbs->shared;
+ unsigned long flags;
+
+ spin_lock_irqsave(&shared->timer_lock, flags);
+
+ /*
+ * Timer handler isn't allowed to queue work at the moment, because:
+ * - Another timer handler has done that
+ * - We are stopping the governor
+ * - Or we are updating the sampling rate of ondemand governor
+ */
+ if (!shared->skip_work) {
+ shared->skip_work++;
+ queue_work(system_wq, &shared->work);
+ }
+
+ spin_unlock_irqrestore(&shared->timer_lock, flags);
}
static void set_sampling_rate(struct dbs_data *dbs_data,
@@ -288,6 +316,8 @@ static int alloc_common_dbs_info(struct cpufreq_policy *policy,
cdata->get_cpu_cdbs(j)->shared = shared;
mutex_init(&shared->timer_mutex);
+ spin_lock_init(&shared->timer_lock);
+ INIT_WORK(&shared->work, dbs_work_handler);
return 0;
}
@@ -452,7 +482,9 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy,
if (ignore_nice)
j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
- INIT_DEFERRABLE_WORK(&j_cdbs->dwork, dbs_timer);
+ __setup_timer(&j_cdbs->timer, dbs_timer_handler,
+ (unsigned long)j_cdbs,
+ TIMER_DEFERRABLE | TIMER_IRQSAFE);
}
if (cdata->governor == GOV_CONSERVATIVE) {
@@ -470,8 +502,7 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy,
od_ops->powersave_bias_init_cpu(cpu);
}
- gov_queue_work(dbs_data, policy, delay_for_sampling_rate(sampling_rate),
- true);
+ gov_add_timers(policy, delay_for_sampling_rate(sampling_rate));
return 0;
}
@@ -485,16 +516,9 @@ static int cpufreq_governor_stop(struct cpufreq_policy *policy,
if (!shared || !shared->policy)
return -EBUSY;
- /*
- * Work-handler must see this updated, as it should not proceed any
- * further after governor is disabled. And so timer_mutex is taken while
- * updating this value.
- */
- mutex_lock(&shared->timer_mutex);
+ gov_cancel_work(shared);
shared->policy = NULL;
- mutex_unlock(&shared->timer_mutex);
- gov_cancel_work(dbs_data, policy);
return 0;
}
diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
index 0c7589016b6c5a81b4d651d1b13b1a21558253f5..76742902491ed4399a43c70364b7d5809c509de9 100644
--- a/drivers/cpufreq/cpufreq_governor.h
+++ b/drivers/cpufreq/cpufreq_governor.h
@@ -132,12 +132,20 @@ static void *get_cpu_dbs_info_s(int cpu) \
struct cpu_common_dbs_info {
struct cpufreq_policy *policy;
/*
- * percpu mutex that serializes governor limit change with dbs_timer
- * invocation. We do not want dbs_timer to run when user is changing
- * the governor or limits.
+ * Per policy mutex that serializes load evaluation from limit-change
+ * and work-handler.
*/
struct mutex timer_mutex;
+
+ /*
+ * Per policy lock that serializes access to queuing work from timer
+ * handlers.
+ */
+ spinlock_t timer_lock;
+
ktime_t time_stamp;
+ unsigned int skip_work;
+ struct work_struct work;
};
/* Per cpu structures */
@@ -152,7 +160,7 @@ struct cpu_dbs_info {
* wake-up from idle.
*/
unsigned int prev_load;
- struct delayed_work dwork;
+ struct timer_list timer;
struct cpu_common_dbs_info *shared;
};
@@ -268,11 +276,11 @@ static ssize_t show_sampling_rate_min_gov_pol \
extern struct mutex cpufreq_governor_lock;
+void gov_add_timers(struct cpufreq_policy *policy, unsigned int delay);
+void gov_cancel_work(struct cpu_common_dbs_info *shared);
void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
int cpufreq_governor_dbs(struct cpufreq_policy *policy,
struct common_dbs_data *cdata, unsigned int event);
-void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
- unsigned int delay, bool all_cpus);
void od_register_powersave_bias_handler(unsigned int (*f)
(struct cpufreq_policy *, unsigned int, unsigned int),
unsigned int powersave_bias);
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index fc0384b4d02d0de6a5c0d83e56c773625fa4c9d8..f879012cf849959ed8a7eaad9b92a93316fc90be 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -286,13 +286,11 @@ static void update_sampling_rate(struct dbs_data *dbs_data,
continue;
next_sampling = jiffies + usecs_to_jiffies(new_rate);
- appointed_at = dbs_info->cdbs.dwork.timer.expires;
+ appointed_at = dbs_info->cdbs.timer.expires;
if (time_before(next_sampling, appointed_at)) {
- cancel_delayed_work_sync(&dbs_info->cdbs.dwork);
-
- gov_queue_work(dbs_data, policy,
- usecs_to_jiffies(new_rate), true);
+ gov_cancel_work(shared);
+ gov_add_timers(policy, usecs_to_jiffies(new_rate));
}
}