[PATCH] make dequeue_task less confusing

From: David Newall
Date: Wed Mar 11 2009 - 10:55:51 EST


The dequeue_patch function in kernel/sched.c is complicated by including
a sleep parameter. This parameter is always zero except in one
instance. This patch clarifies the task of dequeue_patch by removing
the sleep parameter and moving the code that handles non-zero sleep to
that one place where it is needed.
--- linux-2.6.27.19/kernel/sched.c 2009-02-21 09:09:34.000000000 +1030
+++ linux-2.6.27.19/kernel/sched.c.dn 2009-03-12 01:01:48.000000000 +1030
@@ -1645,16 +1645,10 @@
p->se.on_rq = 1;
}

-static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
+static void dequeue_task(struct rq *rq, struct task_struct *p)
{
- if (sleep && p->se.last_wakeup) {
- update_avg(&p->se.avg_overlap,
- p->se.sum_exec_runtime - p->se.last_wakeup);
- p->se.last_wakeup = 0;
- }
-
sched_info_dequeued(p);
- p->sched_class->dequeue_task(rq, p, sleep);
+ p->sched_class->dequeue_task(rq, p, 0);
p->se.on_rq = 0;
}

@@ -1724,7 +1718,17 @@
if (task_contributes_to_load(p))
rq->nr_uninterruptible++;

- dequeue_task(rq, p, sleep);
+ if (sleep && p->se.last_wakeup) {
+ update_avg(&p->se.avg_overlap,
+ p->se.sum_exec_runtime - p->se.last_wakeup);
+ p->se.last_wakeup = 0;
+ }
+
+ /*dequeue_task(rq, p, sleep);*/
+ sched_info_dequeued(p);
+ p->sched_class->dequeue_task(rq, p, sleep);
+ p->se.on_rq = 0;
+
dec_nr_running(rq);
}

@@ -4848,7 +4852,7 @@
on_rq = p->se.on_rq;
running = task_current(rq, p);
if (on_rq)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p);
if (running)
p->sched_class->put_prev_task(rq, p);

@@ -4897,7 +4901,7 @@
}
on_rq = p->se.on_rq;
if (on_rq)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p);

p->static_prio = NICE_TO_PRIO(nice);
set_load_weight(p);
@@ -8637,7 +8641,7 @@
on_rq = tsk->se.on_rq;

if (on_rq)
- dequeue_task(rq, tsk, 0);
+ dequeue_task(rq, tsk);
if (unlikely(running))
tsk->sched_class->put_prev_task(rq, tsk);