Merge branch 'sched/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

torvalds · torvalds · commit 024d4d4c0cf4 · 2018-11-11T16:33:00.000-06:00
Pull scheduler fixes from Thomas Gleixner:
 "Two small scheduler fixes:

   - Take hotplug lock in sched_init_smp(). Technically not really
     required, but lockdep will complain other.

   - Trivial comment fix in sched/fair"

* 'sched/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix a comment in task_numa_fault()
  sched/core: Take the hotplug lock in sched_init_smp()
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
@@ -5851,11 +5851,14 @@ void __init sched_init_smp(void)
 	/*
 	 * There's no userspace yet to cause hotplug operations; hence all the
 	 * CPU masks are stable and all blatant races in the below code cannot
-	 * happen.
+	 * happen. The hotplug lock is nevertheless taken to satisfy lockdep,
+	 * but there won't be any contention on it.
 	 */
+	cpus_read_lock();
 	mutex_lock(&sched_domains_mutex);
 	sched_init_domains(cpu_active_mask);
 	mutex_unlock(&sched_domains_mutex);
+	cpus_read_unlock();
 
 	/* Move init over to a non-isolated CPU */
 	if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
@@ -2400,8 +2400,8 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
 		local = 1;
 
 	/*
-	 * Retry task to preferred node migration periodically, in case it
-	 * case it previously failed, or the scheduler moved us.
+	 * Retry to migrate task to preferred node periodically, in case it
+	 * previously failed, or the scheduler moved us.
 	 */
 	if (time_after(jiffies, p->numa_migrate_retry)) {
 		task_numa_placement(p);
