[RFC PATCH 3/4] sched: define update_stats_curr_start() as a common helper

[Yafang Shao <laoar.shao@gmail.com>]

update_stats_curr_start() is used to update the exec_start when we are
starting a new run period, which is used by all sched class. So we'd
better define it as a common helper.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 kernel/sched/fair.c  | 14 +-------------
 kernel/sched/rt.c    |  2 +-
 kernel/sched/sched.h | 12 ++++++++++++
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index aba21191283d..b762cc3e165c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -914,18 +914,6 @@ update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
 	}
 }
 
-/*
- * We are picking a new current task - update its stats:
- */
-static inline void
-update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-	/*
-	 * We are starting a new run period:
-	 */
-	se->exec_start = rq_clock_task(rq_of(cfs_rq));
-}
-
 /**************************************************
  * Scheduling class queueing methods:
  */
@@ -4254,7 +4242,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 		update_load_avg(cfs_rq, se, UPDATE_TG);
 	}
 
-	update_stats_curr_start(cfs_rq, se);
+	update_stats_curr_start(rq_of(cfs_rq), se);
 	cfs_rq->curr = se;
 
 	/*
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 49ec096a8aa1..b9ec886702a1 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1574,7 +1574,7 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flag
 
 static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool first)
 {
-	p->se.exec_start = rq_clock_task(rq);
+	update_stats_curr_start(rq, &p->se);
 
 	/* The running task is never eligible for pushing */
 	dequeue_pushable_task(rq, p);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e29f2375c4f5..28986736ced9 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2642,3 +2642,15 @@ static inline struct task_struct *task_of(struct sched_entity *se)
 	return container_of(se, struct task_struct, se);
 }
 
+/*
+ * We are picking a new current task - update its stats:
+ */
+static inline void
+update_stats_curr_start(struct rq *rq, struct sched_entity *se)
+{
+	/*
+	 * We are starting a new run period:
+	 */
+	se->exec_start = rq_clock_task(rq);
+}
+
-- 
2.18.4