From 54577e23fa0791599db1a3d86fc8e7a205d3da75 Mon Sep 17 00:00:00 2001 From: Alison Chaiken Date: Tue, 11 Jan 2022 15:32:51 -0800 Subject: [PATCH] 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 Signed-off-by: Paul E. McKenney --- kernel/rcu/tree_nocb.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index 1e40519d1a05..ea889cbfc3b9 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);