| Message ID | 20191113091336.5218-3-k.konieczny@samsung.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | devfreq: improve devfreq statistics counting | expand |
Hi, On 11/13/19 6:13 PM, Kamil Konieczny wrote: > Protect access to devfreq transitions stats with spinlock. You have to add the more detailed reason why spinlock is necessary. And are there any issue without spinlock? In my case, I used the devfreq sysfs entries on Tizen Platfrom for a long time, there are no any issue without spinlock. Regards, Chanwoo Choi > > Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com> > --- > drivers/devfreq/devfreq.c | 18 +++++++++++++++--- > include/linux/devfreq.h | 3 +++ > 2 files changed, 18 insertions(+), 3 deletions(-) > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index 1602cca20fc4..ac04b5baef70 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -163,10 +163,16 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) > cur_time = get_jiffies_64(); > > /* Immediately exit if previous_freq is not initialized yet. */ > - if (!devfreq->previous_freq) > - goto out; > + if (!devfreq->previous_freq) { > + spin_lock(&devfreq->stats_lock); > + devfreq->last_stat_updated = cur_time; > + spin_unlock(&devfreq->stats_lock); > + return 0; > + } > > prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); > + > + spin_lock(&devfreq->stats_lock); > if (prev_lev < 0) { > ret = prev_lev; > goto out; > @@ -174,7 +180,6 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) > > devfreq->time_in_state[prev_lev] += > cur_time - devfreq->last_stat_updated; > - > lev = devfreq_get_freq_level(devfreq, freq); > if (lev < 0) { > ret = lev; > @@ -189,6 +194,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) > > out: > devfreq->last_stat_updated = cur_time; > + spin_unlock(&devfreq->stats_lock); > return ret; > } > EXPORT_SYMBOL(devfreq_update_status); > @@ -478,7 +484,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq) > queue_delayed_work(devfreq_wq, &devfreq->work, > msecs_to_jiffies(devfreq->profile->polling_ms)); > > + spin_lock(&devfreq->stats_lock); > devfreq->last_stat_updated = get_jiffies_64(); > + spin_unlock(&devfreq->stats_lock); > devfreq->stop_polling = false; > > if (devfreq->profile->get_cur_freq && > @@ -707,6 +715,7 @@ struct devfreq *devfreq_add_device(struct device *dev, > } > > devfreq->last_stat_updated = get_jiffies_64(); > + spin_lock_init(&devfreq->stats_lock); > > srcu_init_notifier_head(&devfreq->transition_notifier_list); > > @@ -1405,6 +1414,8 @@ static ssize_t trans_stat_show(struct device *dev, > > len = sprintf(buf, " From : To\n"); > len += sprintf(buf + len, " :"); > + > + spin_lock(&devfreq->stats_lock); > for (i = 0; i < max_state; i++) > len += sprintf(buf + len, "%10lu", > devfreq->profile->freq_table[i]); > @@ -1429,6 +1440,7 @@ static ssize_t trans_stat_show(struct device *dev, > > len += sprintf(buf + len, "Total transition : %u\n", > devfreq->total_trans); > + spin_unlock(&devfreq->stats_lock); > return len; > } > static DEVICE_ATTR_RO(trans_stat); > diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h > index b81a86e47fb9..a344e0be99f3 100644 > --- a/include/linux/devfreq.h > +++ b/include/linux/devfreq.h > @@ -135,6 +135,8 @@ struct devfreq_dev_profile { > * @trans_table: Statistics of devfreq transitions > * @time_in_state: Statistics of devfreq states > * @last_stat_updated: The last time stat updated > + * @stats_lock: Lock protecting trans_table, time_in_state, last_time > + * and total_trans used for statistics > * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier > * > * This structure stores the devfreq information for a give device. > @@ -176,6 +178,7 @@ struct devfreq { > unsigned int *trans_table; > u64 *time_in_state; > unsigned long long last_stat_updated; > + spinlock_t stats_lock; > > struct srcu_notifier_head transition_notifier_list; > }; >
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 1602cca20fc4..ac04b5baef70 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -163,10 +163,16 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) cur_time = get_jiffies_64(); /* Immediately exit if previous_freq is not initialized yet. */ - if (!devfreq->previous_freq) - goto out; + if (!devfreq->previous_freq) { + spin_lock(&devfreq->stats_lock); + devfreq->last_stat_updated = cur_time; + spin_unlock(&devfreq->stats_lock); + return 0; + } prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); + + spin_lock(&devfreq->stats_lock); if (prev_lev < 0) { ret = prev_lev; goto out; @@ -174,7 +180,6 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) devfreq->time_in_state[prev_lev] += cur_time - devfreq->last_stat_updated; - lev = devfreq_get_freq_level(devfreq, freq); if (lev < 0) { ret = lev; @@ -189,6 +194,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) out: devfreq->last_stat_updated = cur_time; + spin_unlock(&devfreq->stats_lock); return ret; } EXPORT_SYMBOL(devfreq_update_status); @@ -478,7 +484,9 @@ void devfreq_monitor_resume(struct devfreq *devfreq) queue_delayed_work(devfreq_wq, &devfreq->work, msecs_to_jiffies(devfreq->profile->polling_ms)); + spin_lock(&devfreq->stats_lock); devfreq->last_stat_updated = get_jiffies_64(); + spin_unlock(&devfreq->stats_lock); devfreq->stop_polling = false; if (devfreq->profile->get_cur_freq && @@ -707,6 +715,7 @@ struct devfreq *devfreq_add_device(struct device *dev, } devfreq->last_stat_updated = get_jiffies_64(); + spin_lock_init(&devfreq->stats_lock); srcu_init_notifier_head(&devfreq->transition_notifier_list); @@ -1405,6 +1414,8 @@ static ssize_t trans_stat_show(struct device *dev, len = sprintf(buf, " From : To\n"); len += sprintf(buf + len, " :"); + + spin_lock(&devfreq->stats_lock); for (i = 0; i < max_state; i++) len += sprintf(buf + len, "%10lu", devfreq->profile->freq_table[i]); @@ -1429,6 +1440,7 @@ static ssize_t trans_stat_show(struct device *dev, len += sprintf(buf + len, "Total transition : %u\n", devfreq->total_trans); + spin_unlock(&devfreq->stats_lock); return len; } static DEVICE_ATTR_RO(trans_stat); diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index b81a86e47fb9..a344e0be99f3 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -135,6 +135,8 @@ struct devfreq_dev_profile { * @trans_table: Statistics of devfreq transitions * @time_in_state: Statistics of devfreq states * @last_stat_updated: The last time stat updated + * @stats_lock: Lock protecting trans_table, time_in_state, last_time + * and total_trans used for statistics * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier * * This structure stores the devfreq information for a give device. @@ -176,6 +178,7 @@ struct devfreq { unsigned int *trans_table; u64 *time_in_state; unsigned long long last_stat_updated; + spinlock_t stats_lock; struct srcu_notifier_head transition_notifier_list; };
Protect access to devfreq transitions stats with spinlock. Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com> --- drivers/devfreq/devfreq.c | 18 +++++++++++++++--- include/linux/devfreq.h | 3 +++ 2 files changed, 18 insertions(+), 3 deletions(-)