[PATCH tip/core/rcu 02/28] rcu: Use kthread_create_on_node()

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

From: Eric Dumazet <eric.dumazet@gmail.com>

Commit a26ac2455ffc (move TREE_RCU from softirq to kthread) added
per-CPU kthreads.  However, kthread creation uses kthread_create(), which
can put the kthread's stack and task struct on the wrong NUMA node.
Therefore, use kthread_create_on_node() instead of kthread_create()
so that the stacks and task structs are placed on the correct NUMA node.

A similar change was carried out in commit 94dcf29a11b3 (kthread:
use kthread_create_on_node()).

Also change rcutorture's priority-boost-test kthread creation.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Tejun Heo <tj@kernel.org>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Andi Kleen <ak@linux.intel.com>
CC: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/rcutorture.c |    3 ++-
 kernel/rcutree.c    |    5 ++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 2e138db..40d9ed2 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -1282,7 +1282,8 @@ static int rcutorture_booster_init(int cpu)
 	/* Don't allow time recalculation while creating a new task. */
 	mutex_lock(&boost_mutex);
 	VERBOSE_PRINTK_STRING("Creating rcu_torture_boost task");
-	boost_tasks[cpu] = kthread_create(rcu_torture_boost, NULL,
+	boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
+						  cpu_to_node(cpu),
 					  "rcu_torture_boost");
 	if (IS_ERR(boost_tasks[cpu])) {
 		retval = PTR_ERR(boost_tasks[cpu]);
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 36e79d2..c67b9f4 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1657,7 +1657,10 @@ static int __cpuinit rcu_spawn_one_cpu_kthread(int cpu)
 	if (!rcu_kthreads_spawnable ||
 	    per_cpu(rcu_cpu_kthread_task, cpu) != NULL)
 		return 0;
-	t = kthread_create(rcu_cpu_kthread, (void *)(long)cpu, "rcuc%d", cpu);
+	t = kthread_create_on_node(rcu_cpu_kthread,
+				   (void *)(long)cpu,
+				   cpu_to_node(cpu),
+				   "rcuc%d", cpu);
 	if (IS_ERR(t))
 		return PTR_ERR(t);
 	if (cpu_online(cpu))
-- 
1.7.3.2