[PATCH 2/3] sched/core: no need to pick again after max is preempted

[Aaron Lu]

When sibling's task preempts current max, there is no need to do the
pick all over again - the preempted cpu could just pick idle and done.

Signed-off-by: Aaron Lu <ziqian.lzq@xxxxxxxxxx>
---
 kernel/sched/core.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 84fec9933b74..e88583860abe 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3756,7 +3756,6 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 	 * order.
 	 */
 	for_each_class(class) {
-again:
 		for_each_cpu_wrap(i, smt_mask, cpu) {
 			struct rq *rq_i = cpu_rq(i);
 			struct task_struct *p;
@@ -3828,10 +3827,10 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 						if (j == i)
 							continue;
 
-						cpu_rq(j)->core_pick = NULL;
+						cpu_rq(j)->core_pick = idle_sched_class.pick_task(cpu_rq(j));
 					}
 					occ = 1;
-					goto again;
+					goto out;
 				} else {
 					/*
 					 * Once we select a task for a cpu, we
@@ -3846,7 +3845,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 		}
 next_class:;
 	}
-
+out:
 	rq->core->core_pick_seq = rq->core->core_task_seq;
 	next = rq->core_pick;
 	rq->core_sched_seq = rq->core->core_pick_seq;
-- 
2.19.1.3.ge56e4f7

patch3: