sched: de-SCHED_OTHER-ize the RT path
The current wake-up code path tries to determine if it can optimize the
wake-up to "this_cpu" by computing load calculations. The problem is that
these calculations are only relevant to SCHED_OTHER tasks where load is king.
For RT tasks, priority is king. So the load calculation is completely wasted
bandwidth.
Therefore, we create a new sched_class interface to help with
pre-wakeup routing decisions and move the load calculation as a function
of CFS task's class.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index b788e35..5de1aeb 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -150,6 +150,13 @@
requeue_task_rt(rq, rq->curr);
}
+#ifdef CONFIG_SMP
+static int select_task_rq_rt(struct task_struct *p, int sync)
+{
+ return task_cpu(p);
+}
+#endif /* CONFIG_SMP */
+
/*
* Preempt the current task with a newly woken task if needed:
*/
@@ -667,6 +674,9 @@
.enqueue_task = enqueue_task_rt,
.dequeue_task = dequeue_task_rt,
.yield_task = yield_task_rt,
+#ifdef CONFIG_SMP
+ .select_task_rq = select_task_rq_rt,
+#endif /* CONFIG_SMP */
.check_preempt_curr = check_preempt_curr_rt,