The menu governer makes separate lookups of the CPU runqueue to get
load and number of IO waiters but it can be done with a single lookup.
Signed-off-by: Mel Gorman <mgor...@suse.de>
---
drivers/cpuidle/governors/menu.c | 17 +++++++----------
include/linux/sched.h | 3 +--
kernel/sched/core.c | 7 +++++++
kernel/sched/proc.c | 7 -------
4 files changed, 15 insertions(+), 19 deletions(-)
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 90d8109..fef0225 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -135,12 +135,9 @@ struct menu_device {
#define LOAD_INT(x) ((x) >> FSHIFT)
#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
-static int get_loadavg(void)
+static inline int get_loadavg(unsigned long load)
{
- unsigned long this = this_cpu_load();
-
-
- return LOAD_INT(this) * 10 + LOAD_FRAC(this) / 10;
+ return LOAD_INT(load) * 10 + LOAD_FRAC(load) / 10;
}
static inline int which_bucket(unsigned int duration, unsigned long
nr_iowaiters)
@@ -176,13 +173,13 @@ static inline int which_bucket(unsigned int duration,
unsigned long nr_iowaiters
* to be, the higher this multiplier, and thus the higher
* the barrier to go to an expensive C state.
*/
-static inline int performance_multiplier(unsigned long nr_iowaiters)
+static inline int performance_multiplier(unsigned long nr_iowaiters, unsigned
long load)
{
int mult = 1;
/* for higher loadavg, we are more reluctant */
- mult += 2 * get_loadavg();
+ mult += 2 * get_loadavg(load);
/* for IO wait tasks (per cpu!) we add 5x each */
mult += 10 * nr_iowaiters;
@@ -297,7 +294,7 @@ static int menu_select(struct cpuidle_driver *drv, struct
cpuidle_device *dev)
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
int i;
unsigned int interactivity_req;
- unsigned long nr_iowaiters;
+ unsigned long nr_iowaiters, cpu_load;
if (data->needs_update) {
menu_update(drv, dev);
@@ -313,7 +310,7 @@ static int menu_select(struct cpuidle_driver *drv, struct
cpuidle_device *dev)
/* determine the expected residency time, round up */
data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length());
- nr_iowaiters = nr_iowait_cpu(smp_processor_id());
+ get_iowait_load(&nr_iowaiters, &cpu_load);
data->bucket = which_bucket(data->next_timer_us, nr_iowaiters);
/*
@@ -332,7 +329,7 @@ static int menu_select(struct cpuidle_driver *drv, struct
cpuidle_device *dev)
* duration / latency ratio. Adjust the latency limit if
* necessary.
*/
- interactivity_req = data->predicted_us /
performance_multiplier(nr_iowaiters);
+ interactivity_req = data->predicted_us /
performance_multiplier(nr_iowaiters, cpu_load);
if (latency_req > interactivity_req)
latency_req = interactivity_req;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0376b05..a696d48 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -168,8 +168,7 @@ extern int nr_processes(void);
extern unsigned long nr_running(void);
extern unsigned long nr_iowait(void);
extern unsigned long nr_iowait_cpu(int cpu);
-extern unsigned long this_cpu_load(void);
-
+extern void get_iowait_load(unsigned long *nr_waiters, unsigned long *load);
extern void calc_global_load(unsigned long ticks);
extern void update_cpu_load_nohz(void);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index bc1638b..cfbbbf3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2385,6 +2385,13 @@ unsigned long nr_iowait_cpu(int cpu)
return atomic_read(&this->nr_iowait);
}
+void get_iowait_load(unsigned long *nr_waiters, unsigned long *load)
+{
+ struct rq *this = this_rq();
+ *nr_waiters = atomic_read(&this->nr_iowait);
+ *load = this->cpu_load[0];
+}
+
#ifdef CONFIG_SMP
/*
diff --git a/kernel/sched/proc.c b/kernel/sched/proc.c
index 16f5a30..8ecd552 100644
--- a/kernel/sched/proc.c
+++ b/kernel/sched/proc.c
@@ -8,13 +8,6 @@
#include "sched.h"
-unsigned long this_cpu_load(void)
-{
- struct rq *this = this_rq();
- return this->cpu_load[0];
-}
-
-
/*
* Global load-average calculations
*
--
1.8.4.5
--
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