Commit 973bee49 authored by Shang XiaoJing's avatar Shang XiaoJing Committed by Peter Zijlstra
Browse files

sched/deadline: Add dl_task_is_earliest_deadline helper 



Wrap repeated code in helper function dl_task_is_earliest_deadline, which
return true if there is no deadline task on the rq at all, or task's
deadline earlier than the whole rq.

Signed-off-by: default avatarShang XiaoJing <shangxiaojing@huawei.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarDaniel Bristot de Oliveira <bristot@kernel.org>
Link: https://lore.kernel.org/r/20220826083453.698-1-shangxiaojing@huawei.com
parent 53aa930d

kernel/sched/deadline.c

+12 −12
Original line number Diff line number Diff line
@@ -1810,6 +1810,14 @@ static void yield_task_dl(struct rq *rq) 


#ifdef CONFIG_SMP



static inline bool dl_task_is_earliest_deadline(struct task_struct *p,

						 struct rq *rq)

{

	return (!rq->dl.dl_nr_running ||

		dl_time_before(p->dl.deadline,

			       rq->dl.earliest_dl.curr));

}



static int find_later_rq(struct task_struct *task);



static int
@@ -1852,9 +1860,7 @@ select_task_rq_dl(struct task_struct *p, int cpu, int flags) 
		int target = find_later_rq(p);



		if (target != -1 &&

				(dl_time_before(p->dl.deadline,

					cpu_rq(target)->dl.earliest_dl.curr) ||

				(cpu_rq(target)->dl.dl_nr_running == 0)))

		    dl_task_is_earliest_deadline(p, cpu_rq(target)))

			cpu = target;

	}

	rcu_read_unlock();
@@ -2221,9 +2227,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq) 


		later_rq = cpu_rq(cpu);



		if (later_rq->dl.dl_nr_running &&

		    !dl_time_before(task->dl.deadline,

					later_rq->dl.earliest_dl.curr)) {

		if (!dl_task_is_earliest_deadline(task, later_rq)) {

			/*

			 * Target rq has tasks of equal or earlier deadline,

			 * retrying does not release any lock and is unlikely
@@ -2251,9 +2255,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq) 
		 * its earliest one has a later deadline than our

		 * task, the rq is a good one.

		 */

		if (!later_rq->dl.dl_nr_running ||

		    dl_time_before(task->dl.deadline,

				   later_rq->dl.earliest_dl.curr))

		if (dl_task_is_earliest_deadline(task, later_rq))

			break;



		/* Otherwise we try again. */
@@ -2424,9 +2426,7 @@ static void pull_dl_task(struct rq *this_rq) 
		 *  - it will preempt the last one we pulled (if any).

		 */

		if (p && dl_time_before(p->dl.deadline, dmin) &&

		    (!this_rq->dl.dl_nr_running ||

		     dl_time_before(p->dl.deadline,

				    this_rq->dl.earliest_dl.curr))) {

		    dl_task_is_earliest_deadline(p, this_rq)) {

			WARN_ON(p == src_rq->curr);

			WARN_ON(!task_on_rq_queued(p));