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Commit 01d36d0a authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

sched: Account rr tasks 



In order to evaluate the scheduler tick dependency without probing
context switches, we need to know how much SCHED_RR and SCHED_FIFO tasks
are enqueued as those policies don't have the same preemption
requirements.

To prepare for that, let's account SCHED_RR tasks, we'll be able to
deduce SCHED_FIFO tasks as well from it and the total RT tasks in the
runqueue.

Reviewed-by: default avatarChris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 555e0c1e

kernel/sched/rt.c

+16 −0
Original line number Diff line number Diff line
@@ -1141,6 +1141,20 @@ unsigned int rt_se_nr_running(struct sched_rt_entity *rt_se) 
		return 1;

}



static inline

unsigned int rt_se_rr_nr_running(struct sched_rt_entity *rt_se)

{

	struct rt_rq *group_rq = group_rt_rq(rt_se);

	struct task_struct *tsk;



	if (group_rq)

		return group_rq->rr_nr_running;



	tsk = rt_task_of(rt_se);



	return (tsk->policy == SCHED_RR) ? 1 : 0;

}



static inline

void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)

{
@@ -1148,6 +1162,7 @@ void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) 


	WARN_ON(!rt_prio(prio));

	rt_rq->rt_nr_running += rt_se_nr_running(rt_se);

	rt_rq->rr_nr_running += rt_se_rr_nr_running(rt_se);



	inc_rt_prio(rt_rq, prio);

	inc_rt_migration(rt_se, rt_rq);
@@ -1160,6 +1175,7 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) 
	WARN_ON(!rt_prio(rt_se_prio(rt_se)));

	WARN_ON(!rt_rq->rt_nr_running);

	rt_rq->rt_nr_running -= rt_se_nr_running(rt_se);

	rt_rq->rr_nr_running -= rt_se_rr_nr_running(rt_se);



	dec_rt_prio(rt_rq, rt_se_prio(rt_se));

	dec_rt_migration(rt_se, rt_rq);

kernel/sched/sched.h

+1 −0
Original line number Diff line number Diff line
@@ -450,6 +450,7 @@ static inline int rt_bandwidth_enabled(void) 
struct rt_rq {

	struct rt_prio_array active;

	unsigned int rt_nr_running;

	unsigned int rr_nr_running;

#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED

	struct {

		int curr; /* highest queued rt task prio */