[PATCH v2] sched/core: Remove unnecessary check for next_task in push_{rt,dl}_task()
In push_{rt,dl}_task(), we call pick_next_pushable{_dl}_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{_dl}_task(). See the following code in pick_next_pushable{_dl}_task(). static struct task_struct *pick_next_pushable{_dl}_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,dl}_task(). Signed-off-by: Muchun Song --- Changes in v2: -also remove unnecessary check in deadline.c -update commit message --- kernel/sched/deadline.c | 5 - kernel/sched/rt.c | 5 - 2 files changed, 10 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 470ba6b464fe..4b0189627318 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2042,11 +2042,6 @@ static int push_dl_task(struct rq *rq) return 0; retry: - if (unlikely(next_task == rq->curr)) { - WARN_ON(1); - return 0; - } - /* * If next_task preempts rq->curr, and rq->curr * can move away, it makes sense to just reschedule 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
[PATCH v2] sched/core: Remove unnecessary check for next_task in push_{rt,dl}_task()
In push_{rt,dl}_task(), we call pick_next_pushable{_dl}_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{_dl}_task(). See the following code in pick_next_pushable{_dl}_task(). static struct task_struct *pick_next_pushable{_dl}_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,dl}_task(). Signed-off-by: Muchun Song --- Changes in v2: -also remove unnecessary check in deadline.c -update commit message --- kernel/sched/deadline.c | 5 - kernel/sched/rt.c | 5 - 2 files changed, 10 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 470ba6b464fe..4b0189627318 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2042,11 +2042,6 @@ static int push_dl_task(struct rq *rq) return 0; retry: - if (unlikely(next_task == rq->curr)) { - WARN_ON(1); - return 0; - } - /* * If next_task preempts rq->curr, and rq->curr * can move away, it makes sense to just reschedule 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