rcu: Use kthread_create_on_node()

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>

2 files changed, 7 insertions, 3 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 98f51b13bb7e..1d2415046154 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -1280,8 +1280,9 @@ 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,
-                                          "rcu_torture_boost");
+        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]);
                 VERBOSE_PRINTK_STRING("rcu_torture_boost task create failed");
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 8aafbb80b8b0..7b850cdc0aee 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1560,7 +1560,10 @@ static int __cpuinit rcu_spawn_one_cpu_kthread(int cpu)
         if (!rcu_scheduler_fully_active ||
             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))