[PATCH] sched: pull tasks when CPU is about to run SCHED_IDLE tasks

[ultrachin]

From: Chen Xiaoguang <xiaoggc...@tencent.com>

Before a CPU switches from running SCHED_NORMAL task to
SCHED_IDLE task, trying to pull SCHED_NORMAL tasks from other
CPU by doing load_balance first.

Signed-off-by: Chen Xiaoguang <xiaoggc...@tencent.com>
Signed-off-by: Chen He <heddc...@tencent.com>
---
 kernel/sched/fair.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ae7ceba..0a26132 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7004,6 +7004,11 @@ struct task_struct *
        struct task_struct *p;
        int new_tasks;
 
+       if (prev &&
+           fair_policy(prev->policy) &&
+           sched_idle_cpu(rq->cpu))
+               goto idle;
+
 again:
        if (!sched_fair_runnable(rq))
                goto idle;
-- 
1.8.3.1