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Date: Thu, 04 Jul 2013 03:02:19 +0400
From: Kirill Tkhai <tkhai@...dex.ru>
To: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc: Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH] sched/rt: Check if rt_se has neighbour in requeue_task_rt()
1)requeue_task_rt: check if entity's next and prev are not the same element.
This guarantees entity is queued and it is not the only in the prio list.
Return 1 if at least one rt_se from the stack was really requeued.
2)Remove on_rt_rq check from requeue_rt_entity() because it is useless now.
Furthermore, it doesn't handle single rt_se case.
3)Make pretty task_tick_rt() more pretty.
Signed-off-by: Kirill Tkhai <tkhai@...dex.ru>
CC: Steven Rostedt <rostedt@...dmis.org>
CC: Ingo Molnar <mingo@...hat.com>
CC: Peter Zijlstra <peterz@...radead.org>
---
kernel/sched/rt.c | 49 +++++++++++++++++++++++--------------------------
1 files changed, 23 insertions(+), 26 deletions(-)
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 01970c8..3213503 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1135,29 +1135,37 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
* Put task to the head or the end of the run list without the overhead of
* dequeue followed by enqueue.
*/
-static void
+static inline void
requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
{
- if (on_rt_rq(rt_se)) {
- struct rt_prio_array *array = &rt_rq->active;
- struct list_head *queue = array->queue + rt_se_prio(rt_se);
+ struct rt_prio_array *array = &rt_rq->active;
+ struct list_head *queue = array->queue + rt_se_prio(rt_se);
- if (head)
- list_move(&rt_se->run_list, queue);
- else
- list_move_tail(&rt_se->run_list, queue);
- }
+ if (head)
+ list_move(&rt_se->run_list, queue);
+ else
+ list_move_tail(&rt_se->run_list, queue);
}
-static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
+static int requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
{
struct sched_rt_entity *rt_se = &p->rt;
- struct rt_rq *rt_rq;
+ int requeued = 0;
for_each_sched_rt_entity(rt_se) {
- rt_rq = rt_rq_of_se(rt_se);
- requeue_rt_entity(rt_rq, rt_se, head);
+ /*
+ * Requeue to the head or tail of prio queue if
+ * rt_se is queued and it is not the only element
+ */
+ if (rt_se->run_list.prev != rt_se->run_list.next) {
+ struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
+
+ requeue_rt_entity(rt_rq, rt_se, head);
+ requeued = 1;
+ }
}
+
+ return requeued;
}
static void yield_task_rt(struct rq *rq)
@@ -1912,8 +1920,6 @@ static void watchdog(struct rq *rq, struct task_struct *p)
static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
{
- struct sched_rt_entity *rt_se = &p->rt;
-
update_curr_rt(rq);
watchdog(rq, p);
@@ -1930,17 +1936,8 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
p->rt.time_slice = sched_rr_timeslice;
- /*
- * Requeue to the end of queue if we (and all of our ancestors) are the
- * only element on the queue
- */
- for_each_sched_rt_entity(rt_se) {
- if (rt_se->run_list.prev != rt_se->run_list.next) {
- requeue_task_rt(rq, p, 0);
- set_tsk_need_resched(p);
- return;
- }
- }
+ if (requeue_task_rt(rq, p, 0))
+ set_tsk_need_resched(p);
}
static void set_curr_task_rt(struct rq *rq)
--
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