[PATCH] sched/rt: fix incorrect schedstats for rt thread

[Dengjun Su]

For RT thread, only 'set_next_task_rt' will call
'update_stats_wait_end_rt' to update schedstats information.
However, during the RT migration process,
'update_stats_wait_start_rt' will be called twice, which
will cause the values of wait_max and wait_sum to be incorrect.
The specific output as follows:
$ cat /proc/6046/task/6046/sched | grep wait
wait_start                                   :             0.000000
wait_max                                     :        496717.080029
wait_sum                                     :       7921540.776553

Add 'update_stats_wait_end_rt' in 'update_stats_dequeue_rt' to
update schedstats information when dequeue_task.

Signed-off-by: Dengjun Su <dengjun.su at mediatek.com>
---
 kernel/sched/rt.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index f1867fe8e5c5..12f2efddca9f 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1302,13 +1302,18 @@ update_stats_dequeue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
 			int flags)
 {
 	struct task_struct *p = NULL;
+	struct rq *rq = rq_of_rt_rq(rt_rq);
 
 	if (!schedstat_enabled())
 		return;
 
-	if (rt_entity_is_task(rt_se))
+	if (rt_entity_is_task(rt_se)) {
 		p = rt_task_of(rt_se);
 
+		if (p != rq->curr)
+			update_stats_wait_end_rt(rt_rq, rt_se);
+	}
+
 	if ((flags & DEQUEUE_SLEEP) && p) {
 		unsigned int state;
 
-- 
2.43.0