[RFC PATCH v1 10/11] cpuidle: update cpuidle governor when needed

Aubrey Li
2017-07-10T01:49:15Z

From: Aubrey Li <aubrey.li@linux.intel.com>

Reflect the data to cpuidle governor when there is an update
---
drivers/cpuidle/cpuidle.c | 6 ++++--
include/linux/cpuidle.h | 1 +
kernel/sched/idle.c | 14 ++++++++++++++
3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 97aacab..9c84c5c 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -387,9 +387,11 @@ unsigned int cpuidle_predict(void)
/*
* Give the governor an opportunity to update on the outcome
*/
- cpuidle_update(drv, dev);
-
gov_stat = (struct cpuidle_governor_stat *)&(dev->gov_stat);
+ if (gov_stat->needs_update) {
+ cpuidle_update(drv, dev);
+ gov_stat->needs_update = 0;
+ }

gov_stat->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length());
get_iowait_load(&nr_iowaiters, &cpu_load);
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index b9964ec..c6a805f 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -79,6 +79,7 @@ struct cpuidle_state {

struct cpuidle_governor_stat {
int last_state_idx;
+ int needs_update;

unsigned int next_timer_us;
unsigned int predicted_us;
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 16a766c..3358db2 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -187,6 +187,7 @@ static void cpuidle_idle_call(void)
* Give the governor an opportunity to reflect on the outcome
*/
cpuidle_reflect(dev, entered_state);
+ dev->gov_stat.needs_update = 1;
}

exit_idle:
@@ -206,6 +207,10 @@ static void cpuidle_idle_call(void)
*/
static void cpuidle_fast(void)
{
+ struct cpuidle_device *dev = cpuidle_get_device();
+ ktime_t time_start, time_end;
+ s64 diff;
+
while (!need_resched()) {
check_pgt_cache();
rmb();
@@ -218,7 +223,16 @@ static void cpuidle_fast(void)
local_irq_disable();
arch_cpu_idle_enter();

+ time_start = ns_to_ktime(local_clock());
default_idle_call();
+ time_end = ns_to_ktime(local_clock());
+
+ diff = ktime_us_delta(time_end, time_start);
+ if (diff > INT_MAX)
+ diff = INT_MAX;
+
+ dev->last_residency = (int) diff;
+ dev->gov_stat.needs_update = 1;

arch_cpu_idle_exit();
}
--
2.7.4