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Commit a0f963c1 authored by Pavankumar Kondeti's avatar Pavankumar Kondeti
Browse files

sched/walt: Improve the scheduler 



This change is for general scheduler improvement.

Change-Id: I288fc9a8858cb29ae9c6993b398a349b4a8c7475
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
parent e168b52f

kernel/sched/rt.c

+56 −0
Original line number Diff line number Diff line
@@ -1652,6 +1652,55 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p) 
	resched_curr(rq);

}



#ifdef CONFIG_SCHED_WALT

#define WALT_RT_PULL_THRESHOLD_NS	250000

static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu);

static void try_pull_rt_task(struct rq *this_rq)

{

	int i, this_cpu = this_rq->cpu, src_cpu = this_cpu;

	struct rq *src_rq;

	struct task_struct *p;



	if (sched_rt_runnable(this_rq))

		return;



	for_each_possible_cpu(i) {

		struct rq *rq = cpu_rq(i);



		if (!has_pushable_tasks(rq))

			continue;



		src_cpu = i;

		break;

	}



	if (src_cpu == this_cpu)

		return;



	src_rq = cpu_rq(src_cpu);

	double_lock_balance(this_rq, src_rq);



	/* lock is dropped, so check again */

	if (sched_rt_runnable(this_rq))

		goto unlock;



	p = pick_highest_pushable_task(src_rq, this_cpu);



	if (!p)

		goto unlock;



	if (sched_ktime_clock() - p->wts.last_wake_ts <

				WALT_RT_PULL_THRESHOLD_NS)

		goto unlock;



	deactivate_task(src_rq, p, 0);

	set_task_cpu(p, this_cpu);

	activate_task(this_rq, p, 0);

unlock:

	double_unlock_balance(this_rq, src_rq);

}

#endif



static int balance_rt(struct rq *rq, struct task_struct *p, struct rq_flags *rf)

{

	if (!on_rt_rq(&p->rt) && need_pull_rt_task(rq, p)) {
@@ -1662,7 +1711,14 @@ static int balance_rt(struct rq *rq, struct task_struct *p, struct rq_flags *rf) 
		 * not yet started the picking loop.

		 */

		rq_unpin_lock(rq, rf);

#ifndef CONFIG_SCHED_WALT

		pull_rt_task(rq);

#else

		if (rt_overloaded(rq))

			pull_rt_task(rq);

		else

			try_pull_rt_task(rq);

#endif

		rq_repin_lock(rq, rf);

	}