sched: Move p->nr_cpus_allowed check to select_task_rq()

Move the p->nr_cpus_allowed check into kernel/sched/core.c: select_task_rq().
This change will make fair.c, rt.c, and deadline.c all start with the
same logic.
Suggested-and-Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "pang.xunlei" <pang.xunlei@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1415150077-59053-1-git-send-email-wanpeng.li@linux.intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

@@ -1411,7 +1411,8 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
 static inline
 int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
 {
-	cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags);
+	if (p->nr_cpus_allowed > 1)
+		cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags);
 
 	/*
 	 * In order not to call set_task_cpu() on a blocking task we need

kernel/sched/deadline.c

@@ -928,9 +928,6 @@ 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;
 

kernel/sched/fair.c

@@ -4730,9 +4730,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
 	int want_affine = 0;
 	int sync = wake_flags & WF_SYNC;
 
-	if (p->nr_cpus_allowed == 1)
-		return prev_cpu;
-
 	if (sd_flag & SD_BALANCE_WAKE)
 		want_affine = cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
 

kernel/sched/rt.c

@@ -1301,9 +1301,6 @@ select_task_rq_rt(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;
-
 	/* For anything but wake ups, just return the task_cpu */
 	if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
 		goto out;