rcu: Rationalize kthread spawning

Currently, RCU spawns kthreads from several different early_initcall()
functions.  Although this has served RCU well for quite some time,
as more kthreads are added a more deterministic approach is required.
This commit therefore causes all of RCU's early-boot kthreads to be
spawned from a single early_initcall() function.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 1b70cb6fbe3c..9be47f43903b 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3489,7 +3489,7 @@ static int rcu_pm_notify(struct notifier_block *self,
 }
 
 /*
- * Spawn the kthread that handles this RCU flavor's grace periods.
+ * Spawn the kthreads that handle each RCU flavor's grace periods.
  */
 static int __init rcu_spawn_gp_kthread(void)
 {
@@ -3498,6 +3498,7 @@ static int __init rcu_spawn_gp_kthread(void)
         struct rcu_state *rsp;
         struct task_struct *t;
 
+        rcu_scheduler_fully_active = 1;
         for_each_rcu_flavor(rsp) {
                 t = kthread_run(rcu_gp_kthread, rsp, "%s", rsp->name);
                 BUG_ON(IS_ERR(t));
@@ -3507,6 +3508,7 @@ static int __init rcu_spawn_gp_kthread(void)
                 raw_spin_unlock_irqrestore(&rnp->lock, flags);
                 rcu_spawn_nocb_kthreads(rsp);
         }
+        rcu_spawn_boost_kthreads();
         return 0;
 }
 early_initcall(rcu_spawn_gp_kthread);