1 files changed, 13 insertions, 13 deletions

diff --git a/kernel/timer.c b/kernel/timer.c
index 99b00a25f88..f3d35d4ea42 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -451,10 +451,18 @@ void add_timer_on(struct timer_list *timer, int cpu)
 	spin_lock_irqsave(&base->lock, flags);
 	timer_set_base(timer, base);
 	internal_add_timer(base, timer);
+	/*
+	 * Check whether the other CPU is idle and needs to be
+	 * triggered to reevaluate the timer wheel when nohz is
+	 * active. We are protected against the other CPU fiddling
+	 * with the timer by holding the timer base lock. This also
+	 * makes sure that a CPU on the way to idle can not evaluate
+	 * the timer wheel.
+	 */
+	wake_up_idle_cpu(cpu);
 	spin_unlock_irqrestore(&base->lock, flags);
 }
 
-
 /**
  * mod_timer - modify a timer's timeout
  * @timer: the timer to be modified
@@ -1220,13 +1228,6 @@ asmlinkage long sys_sysinfo(struct sysinfo __user *info)
 	return 0;
 }
 
-/*
- * lockdep: we want to track each per-CPU base as a separate lock-class,
- * but timer-bases are kmalloc()-ed, so we need to attach separate
- * keys to them:
- */
-static struct lock_class_key base_lock_keys[NR_CPUS];
-
 static int __cpuinit init_timers_cpu(int cpu)
 {
 	int j;
@@ -1269,7 +1270,6 @@ static int __cpuinit init_timers_cpu(int cpu)
 	}
 
 	spin_lock_init(&base->lock);
-	lockdep_set_class(&base->lock, base_lock_keys + cpu);
 
 	for (j = 0; j < TVN_SIZE; j++) {
 		INIT_LIST_HEAD(base->tv5.vec + j);
@@ -1308,8 +1308,8 @@ static void __cpuinit migrate_timers(int cpu)
 	new_base = get_cpu_var(tvec_bases);
 
 	local_irq_disable();
-	double_spin_lock(&new_base->lock, &old_base->lock,
-			 smp_processor_id() < cpu);
+	spin_lock(&new_base->lock);
+	spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
 
 	BUG_ON(old_base->running_timer);
 
@@ -1322,8 +1322,8 @@ static void __cpuinit migrate_timers(int cpu)
 		migrate_timer_list(new_base, old_base->tv5.vec + i);
 	}
 
-	double_spin_unlock(&new_base->lock, &old_base->lock,
-			   smp_processor_id() < cpu);
+	spin_unlock(&old_base->lock);
+	spin_unlock(&new_base->lock);
 	local_irq_enable();
 	put_cpu_var(tvec_bases);
 }