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authorJavi Merino <javi.merino@arm.com>2015-08-14 18:56:56 +0100
committerMyungJoo Ham <myungjoo.ham@samsung.com>2015-09-11 14:23:28 +0900
commit08e75e754a6d9838e490b74551d19fc04d0fd6f9 (patch)
tree71344662250f9bd22389a86e886a1aa6b67c7fed
parent9348da2f1c2ca8e064d4907cdc5b3a19477df933 (diff)
downloadlinux-08e75e754a6d9838e490b74551d19fc04d0fd6f9.tar.bz2
PM / devfreq: cache the last call to get_dev_status()
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: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
-rw-r--r--drivers/devfreq/governor_simpleondemand.c33
-rw-r--r--include/linux/devfreq.h15
2 files changed, 33 insertions, 15 deletions
diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
index 0720ba84ca92..ae72ba5e78df 100644
--- a/drivers/devfreq/governor_simpleondemand.c
+++ b/drivers/devfreq/governor_simpleondemand.c
@@ -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;
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index ce447f0f1bad..70a1c60ddda4 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -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 +205,15 @@ extern int devm_devfreq_register_opp_notifier(struct device *dev,
extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
struct devfreq *devfreq);
+/**
+ * devfreq_update_stats() - update the last_status pointer in struct devfreq
+ * @df: the devfreq instance whose status needs updating
+ */
+static inline int devfreq_update_stats(struct devfreq *df)
+{
+ return df->profile->get_dev_status(df->dev.parent, &df->last_status);
+}
+
#if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
/**
* struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
@@ -289,6 +299,11 @@ 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__ */