[RFC PATCH 1/5] sched: get rq runnable load average for load balance

[Alex Shi]

In load balance, rq load weight is the core of balance judgement.
Now it's time to consider the PJT's runnable load tracking in load
balance.

Since we already have rq runnable_avg_sum and rq load weight,
the rq runnable load average is easy to get:
	runnable_load(rq) = runnable_avg(rq) * weight(rq)

then reuse rq->avg.load_avg_contrib to store the value.

Signed-off-by: Alex Shi <alex.shi@xxxxxxxxx>
---
 kernel/sched/debug.c |    1 +
 kernel/sched/fair.c  |   20 ++++++++++++++++----
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 2cd3c1b..1cd5639 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -71,6 +71,7 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
 		struct sched_avg *avg = &cpu_rq(cpu)->avg;
 		P(avg->runnable_avg_sum);
 		P(avg->runnable_avg_period);
+		P(avg->load_avg_contrib);
 		return;
 	}
 
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a624d3b..bc60e43 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1439,14 +1439,25 @@ static inline void __update_tg_runnable_avg(struct sched_avg *sa,
 static inline void __update_group_entity_contrib(struct sched_entity *se) {}
 #endif
 
-static inline void __update_task_entity_contrib(struct sched_entity *se)
+static inline void __update_load_avg_contrib(struct sched_avg *sa,
+						struct load_weight *load)
 {
 	u32 contrib;
 
 	/* avoid overflowing a 32-bit type w/ SCHED_LOAD_SCALE */
-	contrib = se->avg.runnable_avg_sum * scale_load_down(se->load.weight);
-	contrib /= (se->avg.runnable_avg_period + 1);
-	se->avg.load_avg_contrib = scale_load(contrib);
+	contrib = sa->runnable_avg_sum * scale_load_down(load->weight);
+	contrib /= (sa->runnable_avg_period + 1);
+	sa->load_avg_contrib = scale_load(contrib);
+}
+
+static inline void __update_task_entity_contrib(struct sched_entity *se)
+{
+	__update_load_avg_contrib(&se->avg, &se->load);
+}
+
+static inline void __update_rq_load_contrib(struct rq *rq)
+{
+	__update_load_avg_contrib(&rq->avg, &rq->load);
 }
 
 /* Compute the current contribution to load_avg by se, return any delta */
@@ -1539,6 +1550,7 @@ static inline void update_rq_runnable_avg(struct rq *rq, int runnable)
 {
 	__update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable);
 	__update_tg_runnable_avg(&rq->avg, &rq->cfs);
+	__update_rq_load_contrib(rq);
 }
 
 /* Add the load generated by se into cfs_rq's child load-average */
-- 
1.7.5.4

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