[PATCH] make dequeue_task less confusing

[PATCH] make dequeue_task less confusing

[David Newall]

[-- Attachment #1: Type: text/plain, Size: 313 bytes --]

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.

[-- Attachment #2: sched.patch --]
[-- Type: text/x-patch, Size: 1619 bytes --]

--- 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);
 

Re: [PATCH] make dequeue_task less confusing

[Ingo Molnar]

* David Newall <davidn@davidnewall.com> wrote:

> 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

The patch does not apply cleanly to the latest scheduler tree:

  1 out of 5 hunks FAILED -- rejects in file kernel/sched.c

You can find it at:

  http://people.redhat.com/mingo/tip.git/README

Thanks,

	Ingo