diff options
| -rw-r--r-- | drivers/cpufreq/cpufreq_governor.c | 49 | ||||
| -rw-r--r-- | drivers/cpufreq/cpufreq_governor.h | 9 |
2 files changed, 24 insertions, 34 deletions
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 2d61eae5cc5d..4de12fd35b1f 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -186,22 +186,24 @@ static inline void gov_cancel_timers(struct cpufreq_policy *policy) void gov_cancel_work(struct cpu_common_dbs_info *shared) { - unsigned long flags; - + /* Tell dbs_timer_handler() to skip queuing up work items. */ + atomic_inc(&shared->skip_work); /* - * 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. + * If dbs_timer_handler() is already running, it may not notice the + * incremented skip_work, so wait for it to complete to prevent its work + * item from being queued up after the cancel_work_sync() below. + */ + gov_cancel_timers(shared->policy); + /* + * In case dbs_timer_handler() managed to run and spawn a work item + * before the timers have been canceled, wait for that work item to + * complete and then cancel all of the timers set up by it. If + * dbs_timer_handler() runs again at that point, it will see the + * positive value of skip_work and won't spawn any more work items. */ - 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; + atomic_set(&shared->skip_work, 0); } EXPORT_SYMBOL_GPL(gov_cancel_work); @@ -230,7 +232,6 @@ static void dbs_work_handler(struct work_struct *work) struct cpufreq_policy *policy; struct dbs_data *dbs_data; unsigned int sampling_rate, delay; - unsigned long flags; bool eval_load; policy = shared->policy; @@ -259,9 +260,7 @@ static void dbs_work_handler(struct work_struct *work) 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); + atomic_dec(&shared->skip_work); gov_add_timers(policy, delay); } @@ -270,22 +269,18 @@ 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: + * Timer handler may not be allowed to queue the 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 + * - Or we are updating the sampling rate of the ondemand governor */ - if (!shared->skip_work) { - shared->skip_work++; + if (atomic_inc_return(&shared->skip_work) > 1) + atomic_dec(&shared->skip_work); + else queue_work(system_wq, &shared->work); - } - - spin_unlock_irqrestore(&shared->timer_lock, flags); } static void set_sampling_rate(struct dbs_data *dbs_data, @@ -316,7 +311,7 @@ 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); + atomic_set(&shared->skip_work, 0); INIT_WORK(&shared->work, dbs_work_handler); return 0; } diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h index 76742902491e..91e767a058a7 100644 --- a/drivers/cpufreq/cpufreq_governor.h +++ b/drivers/cpufreq/cpufreq_governor.h @@ -17,6 +17,7 @@ #ifndef _CPUFREQ_GOVERNOR_H #define _CPUFREQ_GOVERNOR_H +#include <linux/atomic.h> #include <linux/cpufreq.h> #include <linux/kernel_stat.h> #include <linux/module.h> @@ -137,14 +138,8 @@ struct cpu_common_dbs_info { */ 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; + atomic_t skip_work; struct work_struct work; }; |