| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Thu, 10 Sep 2015 18:09:28 +0100
From: Javi Merino <javi.merino@....com>
To: linux-pm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, cw00.choi@...sung.com,
edubezval@...il.com, Javi Merino <javi.merino@....com>,
Kyungmin Park <kyungmin.park@...sung.com>,
MyungJoo Ham <myungjoo.ham@...sung.com>
Subject: [PATCH v6 1/5] 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@...sung.com>
Signed-off-by: Javi Merino <javi.merino@....com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@...sung.com>
---
Hi MyungJoo,
The patches in this series haven't changed from what you have in your
tree. I'm only including them because they're not yet in mainline.
drivers/devfreq/governor_simpleondemand.c | 33 +++++++++++++++++--------------
include/linux/devfreq.h | 15 ++++++++++++++
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__ */
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists