[PATCH 17/23] sched,irq: Convert to sched_set_fifo()

From: Peter Zijlstra
Date: Wed Apr 22 2020 - 07:29:54 EST


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: tglx@xxxxxxxxxxxxx
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/irq/manage.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1271,9 +1271,6 @@ static int
setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
{
struct task_struct *t;
- struct sched_param param = {
- .sched_priority = MAX_USER_RT_PRIO/2,
- };

if (!secondary) {
t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
@@ -1281,13 +1278,12 @@ setup_irq_thread(struct irqaction *new,
} else {
t = kthread_create(irq_thread, new, "irq/%d-s-%s", irq,
new->name);
- param.sched_priority -= 1;
}

if (IS_ERR(t))
return PTR_ERR(t);

- sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
+ sched_set_fifo(t);

/*
* We keep the reference to the task struct even if