[PATCH 1/5] sched/pci: Reduce psimon FIFO priority

From: Peter Zijlstra
Date: Thu Aug 01 2019 - 07:18:21 EST

PSI defaults to a FIFO-99 thread, reduce this to FIFO-1.

FIFO-99 is the very highest priority available to SCHED_FIFO and
it not a suitable default; it would indicate the psi work is the
most important work on the machine.

Since Real-Time tasks will have pre-allocated memory and locked it in
place, Real-Time tasks do not care about PSI. All it needs is to be
above OTHER.

Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
kernel/sched/psi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1051,7 +1051,7 @@ struct psi_trigger *psi_trigger_create(s

if (!rcu_access_pointer(group->poll_kworker)) {
struct sched_param param = {
- .sched_priority = MAX_RT_PRIO - 1,
+ .sched_priority = 1,
struct kthread_worker *kworker;