2018-11-03 05:45:58

by Muchun Song

[permalink] [raw]
Subject: [PATCH] sched/rt: Remove unnecessary check for next_task in push_rt_task()

In push_rt_task(), we call pick_next_pushable_task() to pick
next_task before the check. If next_task and rq->curr are equal,
which will trigger BUG_ON() in pick_next_pushable_task(). See
the following code in pick_next_pushable_task().

static struct task_struct *pick_next_pushable_task(struct rq *rq)
{
BUG_ON(task_current(rq, p));
}

The task_current() will check if task p and rq->curr are equal.
So, we can remove the unnecessary check in push_rt_task().

Signed-off-by: Muchun Song <[email protected]>
---
kernel/sched/rt.c | 5 -----
1 file changed, 5 deletions(-)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 481bb7aa25c5..ec097edea9ca 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1813,11 +1813,6 @@ static int push_rt_task(struct rq *rq)
return 0;

retry:
- if (unlikely(next_task == rq->curr)) {
- WARN_ON(1);
- return 0;
- }
-
/*
* It's possible that the next_task slipped in of
* higher priority than current. If that's the case
--
2.17.1