aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorDmitry Adamushko <dmitry.adamushko@gmail.com>2008-07-01 23:32:15 +0200
committerIngo Molnar <mingo@elte.hu>2008-07-18 12:55:14 +0200
commit7ebefa8ceefed44cc321be70afc54a585a68ac0b (patch)
treecab0118d96d704fcca2e52f192f4bb2a7f6a909e
parent13b40c1e40f3261e83ee514a08b77dbecb93021b (diff)
downloadmrst-s0i3-test-7ebefa8ceefed44cc321be70afc54a585a68ac0b.tar.gz
mrst-s0i3-test-7ebefa8ceefed44cc321be70afc54a585a68ac0b.tar.xz
mrst-s0i3-test-7ebefa8ceefed44cc321be70afc54a585a68ac0b.zip
sched: rework of "prioritize non-migratable tasks over migratable ones"
(1) handle in a generic way all cases when a newly woken-up task is not migratable (not just a corner case when "rt_se->nr_cpus_allowed == 1") (2) if current is to be preempted, then make sure "p" will be picked up by pick_next_task_rt(). i.e. move task's group at the head of its list as well. currently, it's not a case for the group-scheduling case as described here: http://www.ussg.iu.edu/hypermail/linux/kernel/0807.0/0134.html Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/sched_rt.c68
1 files changed, 40 insertions, 28 deletions
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 47ceac9e855..d3d1cccb3d7 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -599,11 +599,7 @@ static void __enqueue_rt_entity(struct sched_rt_entity *rt_se)
if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
return;
- if (rt_se->nr_cpus_allowed == 1)
- list_add(&rt_se->run_list, queue);
- else
- list_add_tail(&rt_se->run_list, queue);
-
+ list_add_tail(&rt_se->run_list, queue);
__set_bit(rt_se_prio(rt_se), array->bitmap);
inc_rt_tasks(rt_se, rt_rq);
@@ -688,32 +684,34 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
* Put task to the end of the run list without the overhead of dequeue
* followed by enqueue.
*/
-static
-void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+static void
+requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
{
- struct rt_prio_array *array = &rt_rq->active;
-
if (on_rt_rq(rt_se)) {
- list_del_init(&rt_se->run_list);
- list_add_tail(&rt_se->run_list,
- 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);
}
}
-static void requeue_task_rt(struct rq *rq, struct task_struct *p)
+static void 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;
for_each_sched_rt_entity(rt_se) {
rt_rq = rt_rq_of_se(rt_se);
- requeue_rt_entity(rt_rq, rt_se);
+ requeue_rt_entity(rt_rq, rt_se, head);
}
}
static void yield_task_rt(struct rq *rq)
{
- requeue_task_rt(rq, rq->curr);
+ requeue_task_rt(rq, rq->curr, 0);
}
#ifdef CONFIG_SMP
@@ -753,6 +751,30 @@ static int select_task_rq_rt(struct task_struct *p, int sync)
*/
return task_cpu(p);
}
+
+static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
+{
+ cpumask_t mask;
+
+ if (rq->curr->rt.nr_cpus_allowed == 1)
+ return;
+
+ if (p->rt.nr_cpus_allowed != 1
+ && cpupri_find(&rq->rd->cpupri, p, &mask))
+ return;
+
+ if (!cpupri_find(&rq->rd->cpupri, rq->curr, &mask))
+ return;
+
+ /*
+ * There appears to be other cpus that can accept
+ * current and none to run 'p', so lets reschedule
+ * to try and push current away:
+ */
+ requeue_task_rt(rq, p, 1);
+ resched_task(rq->curr);
+}
+
#endif /* CONFIG_SMP */
/*
@@ -778,18 +800,8 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p)
* to move current somewhere else, making room for our non-migratable
* task.
*/
- if((p->prio == rq->curr->prio)
- && p->rt.nr_cpus_allowed == 1
- && rq->curr->rt.nr_cpus_allowed != 1) {
- cpumask_t mask;
-
- if (cpupri_find(&rq->rd->cpupri, rq->curr, &mask))
- /*
- * There appears to be other cpus that can accept
- * current, so lets reschedule to try and push it away
- */
- resched_task(rq->curr);
- }
+ if (p->prio == rq->curr->prio && !need_resched())
+ check_preempt_equal_prio(rq, p);
#endif
}
@@ -1415,7 +1427,7 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
* on the queue:
*/
if (p->rt.run_list.prev != p->rt.run_list.next) {
- requeue_task_rt(rq, p);
+ requeue_task_rt(rq, p, 0);
set_tsk_need_resched(p);
}
}