sched: Add pre and post wakeup hooks

As will be apparent in the next patch, we need a pre wakeup hook
for sched_fair task migration, hence rename the post wakeup hook
and one pre wakeup.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170518.114746117@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/sched.h

@@ -1091,7 +1091,8 @@ struct sched_class {
 			      enum cpu_idle_type idle);
 	void (*pre_schedule) (struct rq *this_rq, struct task_struct *task);
 	void (*post_schedule) (struct rq *this_rq);
-	void (*task_wake_up) (struct rq *this_rq, struct task_struct *task);
+	void (*task_waking) (struct rq *this_rq, struct task_struct *task);
+	void (*task_woken) (struct rq *this_rq, struct task_struct *task);
 
 	void (*set_cpus_allowed)(struct task_struct *p,
 				 const struct cpumask *newmask);

kernel/sched.c

@@ -2412,6 +2412,10 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
 	if (task_contributes_to_load(p))
 		rq->nr_uninterruptible--;
 	p->state = TASK_WAKING;
+
+	if (p->sched_class->task_waking)
+		p->sched_class->task_waking(rq, p);
+
 	__task_rq_unlock(rq);
 
 	cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
@@ -2475,8 +2479,8 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
 
 	p->state = TASK_RUNNING;
 #ifdef CONFIG_SMP
-	if (p->sched_class->task_wake_up)
-		p->sched_class->task_wake_up(rq, p);
+	if (p->sched_class->task_woken)
+		p->sched_class->task_woken(rq, p);
 
 	if (unlikely(rq->idle_stamp)) {
 		u64 delta = rq->clock - rq->idle_stamp;
@@ -2666,8 +2670,8 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
 	trace_sched_wakeup_new(rq, p, 1);
 	check_preempt_curr(rq, p, WF_FORK);
 #ifdef CONFIG_SMP
-	if (p->sched_class->task_wake_up)
-		p->sched_class->task_wake_up(rq, p);
+	if (p->sched_class->task_woken)
+		p->sched_class->task_woken(rq, p);
 #endif
 	task_rq_unlock(rq, &flags);
 }

kernel/sched_rt.c

@@ -1472,7 +1472,7 @@ static void post_schedule_rt(struct rq *rq)
  * If we are not running and we are not going to reschedule soon, we should
  * try to push tasks away now
  */
-static void task_wake_up_rt(struct rq *rq, struct task_struct *p)
+static void task_woken_rt(struct rq *rq, struct task_struct *p)
 {
 	if (!task_running(rq, p) &&
 	    !test_tsk_need_resched(rq->curr) &&
@@ -1753,7 +1753,7 @@ static const struct sched_class rt_sched_class = {
 	.rq_offline             = rq_offline_rt,
 	.pre_schedule		= pre_schedule_rt,
 	.post_schedule		= post_schedule_rt,
-	.task_wake_up		= task_wake_up_rt,
+	.task_woken		= task_woken_rt,
 	.switched_from		= switched_from_rt,
 #endif