Commit f6b53205 authored by Dmitry Adamushko's avatar Dmitry Adamushko Committed by Ingo Molnar
Browse files

sched: rework enqueue/dequeue_entity() to get rid of set_curr_task() 



rework enqueue/dequeue_entity() to get rid of 
sched_class::set_curr_task(). This simplifies sched_setscheduler(), 
rt_mutex_setprio() and sched_move_tasks().

   text    data     bss     dec     hex filename
  24330    2734      20   27084    69cc sched.o.before
  24233    2730      20   26983    6967 sched.o.after

Signed-off-by: default avatarDmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: default avatarSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 4530d7ab

include/linux/sched.h

+0 −1
Original line number Diff line number Diff line
@@ -871,7 +871,6 @@ struct sched_class { 
			struct sched_domain *sd, enum cpu_idle_type idle,

			int *all_pinned, int *this_best_prio);



	void (*set_curr_task) (struct rq *rq);

	void (*task_tick) (struct rq *rq, struct task_struct *p);

	void (*task_new) (struct rq *rq, struct task_struct *p);

};

kernel/sched.c

+10 −26
Original line number Diff line number Diff line
@@ -3915,8 +3915,8 @@ EXPORT_SYMBOL(sleep_on_timeout); 
 */

void rt_mutex_setprio(struct task_struct *p, int prio)

{

	int oldprio, on_rq, running;

	unsigned long flags;

	int oldprio, on_rq;

	struct rq *rq;



	BUG_ON(prio < 0 || prio > MAX_PRIO);
@@ -3926,12 +3926,8 @@ void rt_mutex_setprio(struct task_struct *p, int prio) 


	oldprio = p->prio;

	on_rq = p->se.on_rq;

	running = task_running(rq, p);

	if (on_rq) {

	if (on_rq)

		dequeue_task(rq, p, 0);

		if (running)

			p->sched_class->put_prev_task(rq, p);

	}



	if (rt_prio(prio))

		p->sched_class = &rt_sched_class;
@@ -3941,15 +3937,13 @@ void rt_mutex_setprio(struct task_struct *p, int prio) 
	p->prio = prio;



	if (on_rq) {

		if (running)

			p->sched_class->set_curr_task(rq);

		enqueue_task(rq, p, 0);

		/*

		 * Reschedule if we are currently running on this runqueue and

		 * our priority decreased, or if we are not currently running on

		 * this runqueue and our priority is higher than the current's

		 */

		if (running) {

		if (task_running(rq, p)) {

			if (p->prio > oldprio)

				resched_task(rq->curr);

		} else {
@@ -4155,7 +4149,7 @@ __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) 
int sched_setscheduler(struct task_struct *p, int policy,

		       struct sched_param *param)

{

	int retval, oldprio, oldpolicy = -1, on_rq, running;

	int retval, oldprio, oldpolicy = -1, on_rq;

	unsigned long flags;

	struct rq *rq;
@@ -4237,24 +4231,20 @@ recheck: 
	}

	update_rq_clock(rq);

	on_rq = p->se.on_rq;

	running = task_running(rq, p);

	if (on_rq) {

	if (on_rq)

		deactivate_task(rq, p, 0);

		if (running)

			p->sched_class->put_prev_task(rq, p);

	}



	oldprio = p->prio;

	__setscheduler(rq, p, policy, param->sched_priority);



	if (on_rq) {

		if (running)

			p->sched_class->set_curr_task(rq);

		activate_task(rq, p, 0);

		/*

		 * Reschedule if we are currently running on this runqueue and

		 * our priority decreased, or if we are not currently running on

		 * this runqueue and our priority is higher than the current's

		 */

		if (running) {

		if (task_running(rq, p)) {

			if (p->prio > oldprio)

				resched_task(rq->curr);

		} else {
@@ -6855,19 +6845,13 @@ static void sched_move_task(struct container_subsys *ss, struct container *cont, 
	running = task_running(rq, tsk);

	on_rq = tsk->se.on_rq;



	if (on_rq) {

	if (on_rq)

		dequeue_task(rq, tsk, 0);

		if (unlikely(running))

			tsk->sched_class->put_prev_task(rq, tsk);

	}



	set_task_cfs_rq(tsk);



	if (on_rq) {

		if (unlikely(running))

			tsk->sched_class->set_curr_task(rq);

	if (on_rq)

		enqueue_task(rq, tsk, 0);

	}



done:

	task_rq_unlock(rq, &flags);

kernel/sched_fair.c

+25 −30
Original line number Diff line number Diff line
@@ -472,8 +472,19 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) 
}



static void

enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)

enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,

		int wakeup, int set_curr)

{

	/*

 	 * In case of the 'current'.

 	 */

	if (unlikely(set_curr)) {

		update_stats_curr_start(cfs_rq, se);

		cfs_rq->curr = se;

		account_entity_enqueue(cfs_rq, se);

		return;

	}



	/*

	 * Update the fair clock.

	 */
@@ -485,7 +496,6 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) 
	}



	update_stats_enqueue(cfs_rq, se);

	if (se != cfs_rq->curr)

	__enqueue_entity(cfs_rq, se);

	account_entity_enqueue(cfs_rq, se);

}
@@ -506,8 +516,12 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) 
		}

	}

#endif

	if (se != cfs_rq->curr)

	if (likely(se != cfs_rq->curr))

		__dequeue_entity(cfs_rq, se);

	else {

		update_stats_curr_end(cfs_rq, se);

		cfs_rq->curr = NULL;

	}

	account_entity_dequeue(cfs_rq, se);

}
@@ -689,12 +703,17 @@ static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup) 
{

	struct cfs_rq *cfs_rq;

	struct sched_entity *se = &p->se;

	int set_curr = 0;



	/* Are we enqueuing the current task? */

	if (unlikely(task_running(rq, p)))

		set_curr = 1;



	for_each_sched_entity(se) {

		if (se->on_rq)

			break;

		cfs_rq = cfs_rq_of(se);

		enqueue_entity(cfs_rq, se, wakeup);

		enqueue_entity(cfs_rq, se, wakeup, set_curr);

	}

}
@@ -742,7 +761,7 @@ static void yield_task_fair(struct rq *rq) 
		 * position within the tree:

		 */

		dequeue_entity(cfs_rq, se, 0);

		enqueue_entity(cfs_rq, se, 0);

		enqueue_entity(cfs_rq, se, 0, 1);



		return;

	}
@@ -985,29 +1004,6 @@ static void task_new_fair(struct rq *rq, struct task_struct *p) 
	resched_task(rq->curr);

}



#ifdef CONFIG_FAIR_GROUP_SCHED

/* Account for a task changing its policy or group.

 *

 * This routine is mostly called to set cfs_rq->curr field when a task

 * migrates between groups/classes.

 */

static void set_curr_task_fair(struct rq *rq)

{

	struct sched_entity *se = &rq->curr->se;



	for_each_sched_entity(se)

		set_next_entity(cfs_rq_of(se), se);

}

#else

static void set_curr_task_fair(struct rq *rq)

{

	struct sched_entity *se = &rq->curr->se;

	struct cfs_rq *cfs_rq = cfs_rq_of(se);



	cfs_rq->curr = se;

}

#endif



/*

 * All the scheduling class methods:

 */
@@ -1023,7 +1019,6 @@ struct sched_class fair_sched_class __read_mostly = { 


	.load_balance		= load_balance_fair,



	.set_curr_task          = set_curr_task_fair,

	.task_tick		= task_tick_fair,

	.task_new		= task_new_fair,

};

kernel/sched_idletask.c

+0 −5
Original line number Diff line number Diff line
@@ -50,10 +50,6 @@ static void task_tick_idle(struct rq *rq, struct task_struct *curr) 
{

}



static void set_curr_task_idle(struct rq *rq)

{

}



/*

 * Simple, special scheduling class for the per-CPU idle tasks:

 */
@@ -70,7 +66,6 @@ static struct sched_class idle_sched_class __read_mostly = { 


	.load_balance		= load_balance_idle,



	.set_curr_task          = set_curr_task_idle,

	.task_tick		= task_tick_idle,

	/* no .task_new for idle tasks */

};

kernel/sched_rt.c

+0 −5
Original line number Diff line number Diff line
@@ -218,10 +218,6 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p) 
	}

}



static void set_curr_task_rt(struct rq *rq)

{

}



static struct sched_class rt_sched_class __read_mostly = {

	.enqueue_task		= enqueue_task_rt,

	.dequeue_task		= dequeue_task_rt,
@@ -234,6 +230,5 @@ static struct sched_class rt_sched_class __read_mostly = { 


	.load_balance		= load_balance_rt,



	.set_curr_task          = set_curr_task_rt,

	.task_tick		= task_tick_rt,

};

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