sched: Pass 'struct rq' to nohz_idle_balance()

The cpu information is stored in the struct rq. Pass the struct rq to
nohz_idle_balance, so all the functions called in run_rebalance_domains have
the same parameters and the 'this_cpu' variable becomes pointless.

Signed-off-by: Daniel Lezcano <[e-mail]>
[ Added !SMP build fix. ]
Signed-off-by: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

kernel/sched/fair.c

···
  * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the
  * rebalancing for all the cpus for whom scheduler ticks are stopped.
  */
-static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle)
+static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
 {
-	struct rq *this_rq = cpu_rq(this_cpu);
+	int this_cpu = this_rq->cpu;
 	struct rq *rq;
 	int balance_cpu;
 
···
 	return 1;
 }
 #else
-static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { }
+static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) { }
 #endif
 
 /*
···
  */
 static void run_rebalance_domains(struct softirq_action *h)
 {
-	int this_cpu = smp_processor_id();
-	struct rq *this_rq = cpu_rq(this_cpu);
+	struct rq *this_rq = this_rq();
 	enum cpu_idle_type idle = this_rq->idle_balance ?
 						CPU_IDLE : CPU_NOT_IDLE;
 
···
 	 * balancing on behalf of the other idle cpus whose ticks are
 	 * stopped.
 	 */
-	nohz_idle_balance(this_cpu, idle);
+	nohz_idle_balance(this_rq, idle);
 }
 
 static inline int on_null_domain(struct rq *rq)