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Commit ea87bb78 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

sched: Extend enqueue_task to allow head queueing 



The ability of enqueueing a task to the head of a SCHED_FIFO priority
list is required to fix some violations of POSIX scheduling policy.

Extend the related functions with a "head" argument.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Tested-by: default avatarCarsten Emde <cbe@osadl.org>
Tested-by: default avatarMathias Weber <mathias.weber.mw1@roche.com>
LKML-Reference: <20100120171629.734886007@linutronix.de>
parent 7c941438

include/linux/sched.h

+2 −1
Original line number Diff line number Diff line
@@ -1067,7 +1067,8 @@ struct sched_domain; 
struct sched_class {

	const struct sched_class *next;



	void (*enqueue_task) (struct rq *rq, struct task_struct *p, int wakeup);

	void (*enqueue_task) (struct rq *rq, struct task_struct *p, int wakeup,

			      bool head);

	void (*dequeue_task) (struct rq *rq, struct task_struct *p, int sleep);

	void (*yield_task) (struct rq *rq);

kernel/sched.c

+7 −6
Original line number Diff line number Diff line
@@ -1856,13 +1856,14 @@ static void update_avg(u64 *avg, u64 sample) 
	*avg += diff >> 3;

}



static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)

static void

enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, bool head)

{

	if (wakeup)

		p->se.start_runtime = p->se.sum_exec_runtime;



	sched_info_queued(p);

	p->sched_class->enqueue_task(rq, p, wakeup);

	p->sched_class->enqueue_task(rq, p, wakeup, head);

	p->se.on_rq = 1;

}
@@ -1892,7 +1893,7 @@ static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) 
	if (task_contributes_to_load(p))

		rq->nr_uninterruptible--;



	enqueue_task(rq, p, wakeup);

	enqueue_task(rq, p, wakeup, false);

	inc_nr_running(rq);

}
@@ -4236,7 +4237,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio) 
	if (running)

		p->sched_class->set_curr_task(rq);

	if (on_rq) {

		enqueue_task(rq, p, 0);

		enqueue_task(rq, p, 0, false);



		check_class_changed(rq, p, prev_class, oldprio, running);

	}
@@ -4280,7 +4281,7 @@ void set_user_nice(struct task_struct *p, long nice) 
	delta = p->prio - old_prio;



	if (on_rq) {

		enqueue_task(rq, p, 0);

		enqueue_task(rq, p, 0, false);

		/*

		 * If the task increased its priority or is running and

		 * lowered its priority, then reschedule its CPU:
@@ -8230,7 +8231,7 @@ void sched_move_task(struct task_struct *tsk) 
	if (unlikely(running))

		tsk->sched_class->set_curr_task(rq);

	if (on_rq)

		enqueue_task(rq, tsk, 0);

		enqueue_task(rq, tsk, 0, false);



	task_rq_unlock(rq, &flags);

}

kernel/sched_fair.c

+2 −1
Original line number Diff line number Diff line
@@ -1053,7 +1053,8 @@ static inline void hrtick_update(struct rq *rq) 
 * increased. Here we update the fair scheduling stats and

 * then put the task into the rbtree:

 */

static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)

static void

enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup, bool head)

{

	struct cfs_rq *cfs_rq;

	struct sched_entity *se = &p->se;

kernel/sched_rt.c

+2 −1
Original line number Diff line number Diff line
@@ -878,7 +878,8 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se) 
/*

 * Adding/removing a task to/from a priority array:

 */

static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)

static void

enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup, bool head)

{

	struct sched_rt_entity *rt_se = &p->rt;