sched: idle: Compute next timer event and pass it the cpuidle framework

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>

5 files changed, 20 insertions, 14 deletions

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index cd0317a66ddb..055d227a6ebc 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -163,7 +163,7 @@ 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;
@@ -174,7 +174,7 @@ 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 53113c2b8bf6..a3b41e006532 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 = this_cpu_ptr(&ladder_devices);
 	struct ladder_device_state *last_state;
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 9b7c0b9b1251..19a61c4ec9f6 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 = this_cpu_ptr(&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 6a0132e1aefe..5ef9ec14d99b 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -123,7 +123,8 @@ 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);
@@ -151,7 +152,8 @@ 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)
@@ -207,7 +209,7 @@ 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 a98e3616e19f..f195fe742e05 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:
 		/*