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>

2 files changed, 23 insertions, 0 deletions

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 8986dafc75b3..5cc234b332bc 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -149,6 +149,7 @@ use_default:
 
 	/* Take note of the planned idle state. */
 	idle_set_state(this_rq(), &drv->states[next_state]);
+	idle_set_state_idx(this_rq(), next_state);
 
 	/*
 	 * Enter the idle state previously returned by the governor decision.
@@ -159,6 +160,7 @@ use_default:
 
 	/* The cpu is no longer idle or about to enter idle. */
 	idle_set_state(this_rq(), NULL);
+	idle_set_state_idx(this_rq(), -1);
 
 	if (broadcast)
 		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e49cb6b85b90..42d1d8dff7c2 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -525,6 +525,7 @@ struct rq {
 #ifdef CONFIG_CPU_IDLE
 	/* Must be inspected within a rcu lock section */
 	struct cpuidle_state *idle_state;
+	int idle_state_idx;
 #endif
 };
 
@@ -1101,6 +1102,17 @@ static inline struct cpuidle_state *idle_get_state(struct rq *rq)
 	WARN_ON(!rcu_read_lock_held());
 	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)
@@ -1111,6 +1123,15 @@ 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 sysrq_sched_debug_show(void);