[tip:sched/core] sched: Make initial SCHED_RR timeslace DEF_TIMESLICE

tip-bot for Hiroshi Shimamoto
2012-02-22T16:13:25Z

Commit-ID: de5bdff7a72acc281219be2b8edeeca1fd81c542
Gitweb: http://git.kernel.org/tip/de5bdff7a72acc281219be2b8edeeca1fd81c542
Author: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
AuthorDate: Thu, 16 Feb 2012 14:52:21 +0900
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 22 Feb 2012 12:28:29 +0100

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: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
[ s/DEF_TIMESLICE/RR_TIMESLICE/g ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4F3C9995.3010800@ct.jp.nec.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
include/linux/init_task.h | 2 +-
include/linux/sched.h | 6 ++++++
kernel/sched/rt.c | 4 ++--
kernel/sched/sched.h | 4 ----
4 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 9c66b1a..f994d51 100644
--- a/include/linux/init_task.h
+++ b/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), \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5dba2ad..eb5de46 100644
--- a/include/linux/sched.h
+++ b/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 {
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index f42ae7f..f70206c 100644
--- a/kernel/sched/rt.c
+++ b/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;
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 8a2c768..c0660a1 100644
--- a/kernel/sched/sched.h
+++ b/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.