[PATCH 2/2] sched/deadline: don't need to balance during wakeup if wakee is pinned

From: Wanpeng Li
Date: Mon Oct 13 2014 - 22:23:07 EST

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 <wanpeng.li@xxxxxxxxxxxxxxx>
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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