[PATCH] sched/deadline: fix rq->dl.pushable_tasks bug in push_dl_task()

[Wanpeng Li]

Do not call dequeue_pushable_dl_task() when failing to push an eligible
task, as it remains pushable, merely not at this particular moment. 
Actually the patch is the same behavior as commit 311e800e16f6 ("sched, 
rt: Fix rq->rt.pushable_tasks bug in push_rt_task()" in -rt side.

Signed-off-by: Wanpeng Li <wanpeng...@linux.intel.com>
---
 kernel/sched/deadline.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index f3d7776..00324af 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1331,6 +1331,7 @@ static int push_dl_task(struct rq *rq)
 {
        struct task_struct *next_task;
        struct rq *later_rq;
+       int ret = 0;
 
        if (!rq->dl.overloaded)
                return 0;
@@ -1376,7 +1377,6 @@ retry:
                         * The task is still there. We don't try
                         * again, some other cpu will pull it when ready.
                         */
-                       dequeue_pushable_dl_task(rq, next_task);
                        goto out;
                }
 
@@ -1392,6 +1392,7 @@ retry:
        deactivate_task(rq, next_task, 0);
        set_task_cpu(next_task, later_rq->cpu);
        activate_task(later_rq, next_task, 0);
+       ret = 1;
 
        resched_curr(later_rq);
 
@@ -1400,7 +1401,7 @@ retry:
 out:
        put_task_struct(next_task);
 
-       return 1;
+       return ret;
 }
 
 static void push_dl_tasks(struct rq *rq)
-- 
1.9.1

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