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Date:	Tue, 14 Oct 2014 10:22:40 +0800
From:	Wanpeng Li <>
To:	Ingo Molnar <>,
	Peter Zijlstra <>
	Wanpeng Li <>
Subject: [PATCH 2/2] sched/deadline: don't need to balance during wakeup if wakee is pinned

Use nr_cpus_allowed to bail from select_task_rq() when only one cpu 
can be used, and saves some cycles for pinned tasks.

Signed-off-by: Wanpeng Li <>
 kernel/sched/deadline.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index f46b7f1..5874bf8 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -914,6 +914,9 @@ select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags)
 	struct task_struct *curr;
 	struct rq *rq;
+	if (p->nr_cpus_allowed == 1)
+		goto out;
 	if (sd_flag != SD_BALANCE_WAKE)
 		goto out;

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