ANDROID: sched, cpuidle: Track cpuidle state index in the scheduler

The idle-state of each cpu is currently pointed to by rq->idle_state but
there isn't any information in the struct cpuidle_state that can used to
look up the idle-state energy model data stored in struct
sched_group_energy. For this purpose is necessary to store the idle
state index as well. Ideally, the idle-state data should be unified.

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Change-Id: Ib3d1178512735b0e314881f73fb8ccff5a69319f
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
(cherry picked from commit a732c97420e109956c20f34c70b91e6d06f5df31)
[ Fixed trivial cherry-pick conflict in kernel/sched/sched.h ]
Signed-off-by: Quentin Perret <quentin.perret@arm.com>

4 files changed, 26 insertions, 4 deletions

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 6df894d65d9e..96a3a9bf8b12 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -221,7 +221,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
 	}
 
 	/* Take note of the planned idle state. */
-	sched_idle_set_state(target_state);
+	sched_idle_set_state(target_state, index);
 
 	trace_cpu_idle_rcuidle(index, dev->cpu);
 	time_start = ns_to_ktime(local_clock());
@@ -235,7 +235,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
 	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
 
 	/* The cpu is no longer idle or about to enter idle. */
-	sched_idle_set_state(NULL);
+	sched_idle_set_state(NULL, -1);
 
 	if (broadcast) {
 		if (WARN_ON_ONCE(!irqs_disabled()))
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 4325d6fdde9b..35b067126e9a 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -219,7 +219,7 @@ static inline void cpuidle_use_deepest_state(bool enable)
 #endif
 
 /* kernel/sched/idle.c */
-extern void sched_idle_set_state(struct cpuidle_state *idle_state);
+extern void sched_idle_set_state(struct cpuidle_state *idle_state, int index);
 extern void default_idle_call(void);
 
 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 16f84142f2f4..2d3e2804c08b 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -16,9 +16,10 @@ extern char __cpuidle_text_start[], __cpuidle_text_end[];
  * sched_idle_set_state - Record idle state for the current CPU.
  * @idle_state: State to record.
  */
-void sched_idle_set_state(struct cpuidle_state *idle_state)
+void sched_idle_set_state(struct cpuidle_state *idle_state, int index)
 {
 	idle_set_state(this_rq(), idle_state);
+	idle_set_state_idx(this_rq(), index);
 }
 
 static int __read_mostly cpu_idle_force_poll;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index c6898fa67cba..4a368968d046 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -942,6 +942,7 @@ struct rq {
 #ifdef CONFIG_CPU_IDLE
 	/* Must be inspected within a rcu lock section */
 	struct cpuidle_state	*idle_state;
+	int			idle_state_idx;
 #endif
 };
 
@@ -1642,6 +1643,17 @@ static inline struct cpuidle_state *idle_get_state(struct rq *rq)
 
 	return rq->idle_state;
 }
+
+static inline void idle_set_state_idx(struct rq *rq, int idle_state_idx)
+{
+	rq->idle_state_idx = idle_state_idx;
+}
+
+static inline int idle_get_state_idx(struct rq *rq)
+{
+	WARN_ON(!rcu_read_lock_held());
+	return rq->idle_state_idx;
+}
 #else
 static inline void idle_set_state(struct rq *rq,
 				  struct cpuidle_state *idle_state)
@@ -1652,6 +1664,15 @@ static inline struct cpuidle_state *idle_get_state(struct rq *rq)
 {
 	return NULL;
 }
+
+static inline void idle_set_state_idx(struct rq *rq, int idle_state_idx)
+{
+}
+
+static inline int idle_get_state_idx(struct rq *rq)
+{
+	return -1;
+}
 #endif
 
 extern void schedule_idle(void);