diff options
| -rw-r--r-- | drivers/cpufreq/cpufreq_governor.c | 142 | ||||
| -rw-r--r-- | drivers/cpufreq/cpufreq_governor.h | 20 | ||||
| -rw-r--r-- | drivers/cpufreq/cpufreq_ondemand.c | 8 |
3 files changed, 100 insertions, 70 deletions
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 999e1f6addf9..2d61eae5cc5d 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 0c7589016b6c..76742902491e 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 fc0384b4d02d..f879012cf849 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)); } } |