linux-kernel - [PATCH 21/23] sched,psi: Convert to sched_set_fifo

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Message-Id: <20200422112832.465990342@infradead.org>
Date:   Wed, 22 Apr 2020 13:27:40 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     mingo@...nel.org, linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de, rostedt@...dmis.org, qais.yousef@....com,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, bsegall@...gle.com, mgorman@...e.de,
        peterz@...radead.org, hannes@...xchg.org
Subject: [PATCH 21/23] sched,psi: Convert to sched_set_fifo_low()

Because SCHED_FIFO is a broken scheduler model (see previous patches)
take away the priority field, the kernel can't possibly make an
informed decision.

Effectively no change.

Cc: hannes@...xchg.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Ingo Molnar <mingo@...nel.org>
---
 kernel/sched/psi.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1100,9 +1100,6 @@ struct psi_trigger *psi_trigger_create(s
 	mutex_lock(&group->trigger_lock);
 
 	if (!rcu_access_pointer(group->poll_kworker)) {
-		struct sched_param param = {
-			.sched_priority = 1,
-		};
 		struct kthread_worker *kworker;
 
 		kworker = kthread_create_worker(0, "psimon");
@@ -1111,7 +1108,7 @@ struct psi_trigger *psi_trigger_create(s
 			mutex_unlock(&group->trigger_lock);
 			return ERR_CAST(kworker);
 		}
-		sched_setscheduler_nocheck(kworker->task, SCHED_FIFO, &param);
+		sched_set_fifo_low(kworker->task);
 		kthread_init_delayed_work(&group->poll_work,
 				psi_poll_work);
 		rcu_assign_pointer(group->poll_kworker, kworker);