@@ -768,6 +768,11 @@ err_out:
}
EXPORT_SYMBOL(devfreq_remove_governor);
+int devfreq_update_stats(struct devfreq *df)
+{
+ return df->profile->get_dev_status(df->dev.parent, &df->last_status);
+}
+
static ssize_t governor_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -21,17 +21,20 @@
static int devfreq_simple_ondemand_func(struct devfreq *df,
unsigned long *freq)
{
- struct devfreq_dev_status stat;
- int err = df->profile->get_dev_status(df->dev.parent, &stat);
+ int err;
+ struct devfreq_dev_status *stat;
unsigned long long a, b;
unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD;
unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL;
struct devfreq_simple_ondemand_data *data = df->data;
unsigned long max = (df->max_freq) ? df->max_freq : UINT_MAX;
+ err = devfreq_update_stats(df);
if (err)
return err;
+ stat = &df->last_status;
+
if (data) {
if (data->upthreshold)
dfso_upthreshold = data->upthreshold;
@@ -43,41 +46,41 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
return -EINVAL;
/* Assume MAX if it is going to be divided by zero */
- if (stat.total_time == 0) {
+ if (stat->total_time == 0) {
*freq = max;
return 0;
}
/* Prevent overflow */
- if (stat.busy_time >= (1 << 24) || stat.total_time >= (1 << 24)) {
- stat.busy_time >>= 7;
- stat.total_time >>= 7;
+ if (stat->busy_time >= (1 << 24) || stat->total_time >= (1 << 24)) {
+ stat->busy_time >>= 7;
+ stat->total_time >>= 7;
}
/* Set MAX if it's busy enough */
- if (stat.busy_time * 100 >
- stat.total_time * dfso_upthreshold) {
+ if (stat->busy_time * 100 >
+ stat->total_time * dfso_upthreshold) {
*freq = max;
return 0;
}
/* Set MAX if we do not know the initial frequency */
- if (stat.current_frequency == 0) {
+ if (stat->current_frequency == 0) {
*freq = max;
return 0;
}
/* Keep the current frequency */
- if (stat.busy_time * 100 >
- stat.total_time * (dfso_upthreshold - dfso_downdifferential)) {
- *freq = stat.current_frequency;
+ if (stat->busy_time * 100 >
+ stat->total_time * (dfso_upthreshold - dfso_downdifferential)) {
+ *freq = stat->current_frequency;
return 0;
}
/* Set the desired frequency based on the load */
- a = stat.busy_time;
- a *= stat.current_frequency;
- b = div_u64(a, stat.total_time);
+ a = stat->busy_time;
+ a *= stat->current_frequency;
+ b = div_u64(a, stat->total_time);
b *= 100;
b = div_u64(b, (dfso_upthreshold - dfso_downdifferential / 2));
*freq = (unsigned long) b;
@@ -161,6 +161,7 @@ struct devfreq {
struct delayed_work work;
unsigned long previous_freq;
+ struct devfreq_dev_status last_status;
void *data; /* private data for governors */
@@ -204,6 +205,8 @@ extern int devm_devfreq_register_opp_notifier(struct device *dev,
extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
struct devfreq *devfreq);
+int devfreq_update_stats(struct devfreq *df);
+
#if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
/**
* struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
@@ -289,6 +292,11 @@ static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
struct devfreq *devfreq)
{
}
+
+static inline int devfreq_update_stats(struct devfreq *df)
+{
+ return -EINVAL;
+}
#endif /* CONFIG_PM_DEVFREQ */
#endif /* __LINUX_DEVFREQ_H__ */
The return value of get_dev_status() can be reused. Cache it so that other parts of the kernel can reuse it instead of having to call the same function again. Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Javi Merino <javi.merino@arm.com> --- This patch tries to let multiple components use the infromation from get_dev_status(). To summarize the discussion in v1[1] I can think of three alternatives: 1) Change get_dev_status() to return absolute values for busy_time and total_time 2) Make core devfreq call get_dev_status() periodically (for example, before calling the governor) and all the entities that want access can do so via a pointer in devfreq 3) Cache the periodic call that the simple ondemand governor does periodically and cache it, forcing all the other entities to rely on that governor being active This patch implements option 3) [1] http://thread.gmane.org/gmane.linux.power-management.general/61936/focus=61993 drivers/devfreq/devfreq.c | 5 +++++ drivers/devfreq/governor_simpleondemand.c | 33 +++++++++++++++++-------------- include/linux/devfreq.h | 8 ++++++++ 3 files changed, 31 insertions(+), 15 deletions(-)