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Subject[RFD PATCH 04/10] sched: idle: Compute next timer event and pass it the cpuidle framework
Date
Following the logic of the previous patch, retrieve from the idle task the
expected timer sleep duration and pass it to the cpuidle framework.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/cpuidle/cpuidle.c | 4 ++--
drivers/cpuidle/governors/ladder.c | 3 ++-
drivers/cpuidle/governors/menu.c | 8 ++------
include/linux/cpuidle.h | 8 +++++---
kernel/sched/idle.c | 11 +++++++++--
5 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 372c36f..658be9f 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -159,7 +159,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
* Returns the index of the idle state.
*/
int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
- int latency_req)
+ int latency_req, int next_event)
{
if (off || !initialized)
return -ENODEV;
@@ -170,7 +170,7 @@ int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
if (unlikely(use_deepest_state))
return cpuidle_find_deepest_state(drv, dev);

- return cpuidle_curr_governor->select(drv, dev, latency_req);
+ return cpuidle_curr_governor->select(drv, dev, latency_req, next_event);
}

/**
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index 18f0da9..17381c3 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -64,7 +64,8 @@ static inline void ladder_do_selection(struct ladder_device *ldev,
* @dev: the CPU
*/
static int ladder_select_state(struct cpuidle_driver *drv,
- struct cpuidle_device *dev, int latency_req)
+ struct cpuidle_device *dev,
+ int latency_req, int next_event)
{
struct ladder_device *ldev = &__get_cpu_var(ladder_devices);
struct ladder_device_state *last_state;
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 96f8fb0..9da11ce 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -13,10 +13,6 @@
#include <linux/kernel.h>
#include <linux/cpuidle.h>
#include <linux/pm_qos.h>
-#include <linux/time.h>
-#include <linux/ktime.h>
-#include <linux/hrtimer.h>
-#include <linux/tick.h>
#include <linux/sched.h>
#include <linux/math64.h>
#include <linux/module.h>
@@ -288,7 +284,7 @@ again:
* @dev: the CPU
*/
static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
- int latency_req)
+ int latency_req, int next_event)
{
struct menu_device *data = &__get_cpu_var(menu_devices);
int i;
@@ -303,7 +299,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;

/* determine the expected residency time, round up */
- data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length());
+ data->next_timer_us = next_event;

get_iowait_load(&nr_iowaiters, &cpu_load);
data->bucket = which_bucket(data->next_timer_us, nr_iowaiters);
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index fb465c1..b379ae5 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -122,7 +122,8 @@ struct cpuidle_driver {
extern void disable_cpuidle(void);

extern int cpuidle_select(struct cpuidle_driver *drv,
- struct cpuidle_device *dev, int latency_req);
+ struct cpuidle_device *dev,
+ int latency_req, int next_event);
extern int cpuidle_enter(struct cpuidle_driver *drv,
struct cpuidle_device *dev, int index);
extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
@@ -150,7 +151,8 @@ extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
#else
static inline void disable_cpuidle(void) { }
static inline int cpuidle_select(struct cpuidle_driver *drv,
- struct cpuidle_device *dev, int latency_req)
+ struct cpuidle_device *dev,
+ int latency_req, int next_event)
{return -ENODEV; }
static inline int cpuidle_enter(struct cpuidle_driver *drv,
struct cpuidle_device *dev, int index)
@@ -206,7 +208,7 @@ struct cpuidle_governor {

int (*select) (struct cpuidle_driver *drv,
struct cpuidle_device *dev,
- int latency_req);
+ int latency_req, int next_event);
void (*reflect) (struct cpuidle_device *dev, int index);

struct module *owner;
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 72955e9..7b6a148 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -79,8 +79,8 @@ static void cpuidle_idle_call(void)
{
struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+ struct timespec t;
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
- int next_state, entered_state;
unsigned int broadcast;

/*
@@ -112,11 +112,18 @@ static void cpuidle_idle_call(void)
if (latency_req == 0)
goto use_default;

+ t = ktime_to_timespec(tick_nohz_get_sleep_length());
+
+ /*
+ * The next timer event for this in us
+ */
+ next_event = t.tv_sec * USEC_PER_SEC + t.tv_nsec / NSEC_PER_USEC;
+
/*
* Ask the cpuidle framework to choose a convenient idle state.
* Fall back to the default arch idle method on errors.
*/
- next_state = cpuidle_select(drv, dev, latency_req);
+ next_state = cpuidle_select(drv, dev, latency_req, next_event);
if (next_state < 0) {
use_default:
/*
--
1.9.1


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