sched: Make initial SCHED_RR timeslace DEF_TIMESLICE

Current the initial SCHED_RR timeslice of init_task is HZ, which means
1s, and is not same as the default SCHED_RR timeslice DEF_TIMESLICE.

Change that initial timeslice to the DEF_TIMESLICE.
Signed-off-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
[ s/DEF_TIMESLICE/RR_TIMESLICE/g ]
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4F3C9995.3010800@ct.jp.nec.comSigned-off-by: NIngo Molnar <mingo@elte.hu>

include/linux/init_task.h

@@ -149,7 +149,7 @@ extern struct cred init_cred;
 	},								\
 	.rt		= {						\
 		.run_list	= LIST_HEAD_INIT(tsk.rt.run_list),	\
-		.time_slice	= HZ, 					\
+		.time_slice	= RR_TIMESLICE,				\
 		.nr_cpus_allowed = NR_CPUS,				\
 	},								\
 	.tasks		= LIST_HEAD_INIT(tsk.tasks),			\

include/linux/sched.h

@@ -1234,6 +1234,12 @@ struct sched_rt_entity {
 #endif
 };
 
+/*
+ * default timeslice is 100 msecs (used only for SCHED_RR tasks).
+ * Timeslices get refilled after they expire.
+ */
+#define RR_TIMESLICE		(100 * HZ / 1000)
+
 struct rcu_node;
 
 enum perf_event_task_context {

kernel/sched/rt.c

@@ -1972,7 +1972,7 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
 	if (--p->rt.time_slice)
 		return;
 
-	p->rt.time_slice = DEF_TIMESLICE;
+	p->rt.time_slice = RR_TIMESLICE;
 
 	/*
 	 * Requeue to the end of queue if we are not the only element
@@ -2000,7 +2000,7 @@ static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
 	 * Time slice is 0 for SCHED_FIFO tasks
 	 */
 	if (task->policy == SCHED_RR)
-		return DEF_TIMESLICE;
+		return RR_TIMESLICE;
 	else
 		return 0;
 }

kernel/sched/sched.h

@@ -36,11 +36,7 @@ extern __read_mostly int scheduler_running;
 
 /*
  * These are the 'tuning knobs' of the scheduler:
- *
- * default timeslice is 100 msecs (used only for SCHED_RR tasks).
- * Timeslices get refilled after they expire.
  */
-#define DEF_TIMESLICE		(100 * HZ / 1000)
 
 /*
  * single value that denotes runtime == period, ie unlimited time.