commit dcbb4a153971ff8646af0c963f5698bf21bfbfdc
author Linus Torvalds <torvalds@linux-foundation.org> Sat Aug 10 15:48:02 2019 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> Sat Aug 10 15:48:02 2019 -0700
tree 30f0c6e59d159ac32b98ead9fdb890a2ecbc24d6
parent ed254bb54fed18549b96285cfdadd69780f52c14
parent 04e048cf09d7b5fc995817cdc5ae1acd4482429c

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Thomas Gleixner:
 "Three fixlets for the scheduler:

   - Avoid double bandwidth accounting in the push & pull code

   - Use a sane FIFO priority for the Pressure Stall Information (PSI)
     thread.

   - Avoid permission checks when setting the scheduler params for the
     PSI thread"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/psi: Do not require setsched permission from the trigger creator
  sched/psi: Reduce psimon FIFO priority
  sched/deadline: Fix double accounting of rq/running bw in push & pull

kernel/sched/deadline.c

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index ef5b9f6..46122ed 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2088,17 +2088,13 @@
 	}
 
 	deactivate_task(rq, next_task, 0);
-	sub_running_bw(&next_task->dl, &rq->dl);
-	sub_rq_bw(&next_task->dl, &rq->dl);
 	set_task_cpu(next_task, later_rq->cpu);
-	add_rq_bw(&next_task->dl, &later_rq->dl);
 
 	/*
 	 * Update the later_rq clock here, because the clock is used
 	 * by the cpufreq_update_util() inside __add_running_bw().
 	 */
 	update_rq_clock(later_rq);
-	add_running_bw(&next_task->dl, &later_rq->dl);
 	activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
 	ret = 1;
 
@@ -2186,11 +2182,7 @@
 			resched = true;
 
 			deactivate_task(src_rq, p, 0);
-			sub_running_bw(&p->dl, &src_rq->dl);
-			sub_rq_bw(&p->dl, &src_rq->dl);
 			set_task_cpu(p, this_cpu);
-			add_rq_bw(&p->dl, &this_rq->dl);
-			add_running_bw(&p->dl, &this_rq->dl);
 			activate_task(this_rq, p, 0);
 			dmin = p->dl.deadline;
 

kernel/sched/psi.c

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 7acc632..23fbbcc 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1051,7 +1051,7 @@
 
 	if (!rcu_access_pointer(group->poll_kworker)) {
 		struct sched_param param = {
-			.sched_priority = MAX_RT_PRIO - 1,
+			.sched_priority = 1,
 		};
 		struct kthread_worker *kworker;
 
@@ -1061,7 +1061,7 @@
 			mutex_unlock(&group->trigger_lock);
 			return ERR_CAST(kworker);
 		}
-		sched_setscheduler(kworker->task, SCHED_FIFO, &param);
+		sched_setscheduler_nocheck(kworker->task, SCHED_FIFO, &param);
 		kthread_init_delayed_work(&group->poll_work,
 				psi_poll_work);
 		rcu_assign_pointer(group->poll_kworker, kworker);