[tip: sched/core] sched/fair: Define sched_idle_cpu() only for SMP configurations

[tip-bot2 for Viresh Kumar]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     afa70d941f663c69c9a64ec1021bbcfa82f0e54a
Gitweb:        https://git.kernel.org/tip/afa70d941f663c69c9a64ec1021bbcfa82f0e54a
Author:        Viresh Kumar <viresh.kumar@xxxxxxxxxx>
AuthorDate:    Mon, 20 Jan 2020 11:29:05 +05:30
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Mon, 20 Jan 2020 08:03:39 +01:00

sched/fair: Define sched_idle_cpu() only for SMP configurations

sched_idle_cpu() isn't used for non SMP configuration and with a recent
change, we have started getting following warning:

  kernel/sched/fair.c:5221:12: warning: âsched_idle_cpuâ defined but not used [-Wunused-function]

Fix that by defining sched_idle_cpu() only for SMP configurations.

Fixes: 323af6deaf70 ("sched/fair: Load balance aggressively for SCHED_IDLE CPUs")
Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Link: https://lore.kernel.org/r/f0554f590687478b33914a4aff9f0e6a62886d44.1579499907.git.viresh.kumar@xxxxxxxxxx
---
 kernel/sched/fair.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ebf5095..fe4e0d7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5218,10 +5218,12 @@ static int sched_idle_rq(struct rq *rq)
 			rq->nr_running);
 }
 
+#ifdef CONFIG_SMP
 static int sched_idle_cpu(int cpu)
 {
 	return sched_idle_rq(cpu_rq(cpu));
 }
+#endif
 
 /*
  * The enqueue_task method is called before nr_running is