rcu: Make priority of grace-period thread consistent
The priority of RCU grace period threads is set to kthread_prio when
they are launched from rcu_spawn_gp_kthread(). The same is not true
of rcu_spawn_one_nocb_kthread(). Accordingly, add priority elevation
to rcu_spawn_one_nocb_kthread().
Signed-off-by: Alison Chaiken <achaiken@aurora.tech>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index 1e40519..ea889cb 100644
--- a/kernel/rcu/tree_nocb.h
+++ b/kernel/rcu/tree_nocb.h
@@ -1239,6 +1239,7 @@ static void rcu_spawn_cpu_nocb_kthread(int cpu)
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
struct rcu_data *rdp_gp;
struct task_struct *t;
+ struct sched_param sp;
if (!rcu_scheduler_fully_active || !rcu_nocb_is_setup)
return;
@@ -1248,6 +1249,7 @@ static void rcu_spawn_cpu_nocb_kthread(int cpu)
return;
/* If we didn't spawn the GP kthread first, reorganize! */
+ sp.sched_priority = kthread_prio;
rdp_gp = rdp->nocb_gp_rdp;
mutex_lock(&rdp_gp->nocb_gp_kthread_mutex);
if (!rdp_gp->nocb_gp_kthread) {
@@ -1258,6 +1260,8 @@ static void rcu_spawn_cpu_nocb_kthread(int cpu)
return;
}
WRITE_ONCE(rdp_gp->nocb_gp_kthread, t);
+ if (kthread_prio)
+ sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
}
mutex_unlock(&rdp_gp->nocb_gp_kthread_mutex);
