[RFCv3 PATCH 35/48] sched, cpuidle: Track cpuidle state index in the scheduler

[Morten Rasmussen]

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@xxxxxxxxxx>
cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

Signed-off-by: Morten Rasmussen <morten.rasmussen@xxxxxxx>
---
 kernel/sched/idle.c  |  2 ++
 kernel/sched/sched.h | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index c47fce7..e46c85c 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -149,6 +149,7 @@ static void cpuidle_idle_call(void)
 
 	/* 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 @@ static void cpuidle_idle_call(void)
 
 	/* 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 dedf0ec..107f478 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -678,6 +678,7 @@ struct rq {
 #ifdef CONFIG_CPU_IDLE
 	/* Must be inspected within a rcu lock section */
 	struct cpuidle_state *idle_state;
+	int idle_state_idx;
 #endif
 };
 
@@ -1274,6 +1275,17 @@ 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)
@@ -1284,6 +1296,15 @@ 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);
-- 
1.9.1

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