1 files changed, 59 insertions, 16 deletions

diff --git a/kernel/timer.c b/kernel/timer.c
index 9199f3c52215..f1b8afe1ad86 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -90,8 +90,13 @@ static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
 
 /*
  * Note that all tvec_bases are 2 byte aligned and lower bit of
- * base in timer_list is guaranteed to be zero. Use the LSB for
- * the new flag to indicate whether the timer is deferrable
+ * base in timer_list is guaranteed to be zero. Use the LSB to
+ * indicate whether the timer is deferrable.
+ *
+ * A deferrable timer will work normally when the system is busy, but
+ * will not cause a CPU to come out of idle just to service it; instead,
+ * the timer will be serviced when the CPU eventually wakes up with a
+ * subsequent non-deferrable timer.
  */
 #define TBASE_DEFERRABLE_FLAG		(0x1)
 
@@ -577,6 +582,19 @@ static void __init_timer(struct timer_list *timer,
 	lockdep_init_map(&timer->lockdep_map, name, key, 0);
 }
 
+void setup_deferrable_timer_on_stack_key(struct timer_list *timer,
+					 const char *name,
+					 struct lock_class_key *key,
+					 void (*function)(unsigned long),
+					 unsigned long data)
+{
+	timer->function = function;
+	timer->data = data;
+	init_timer_on_stack_key(timer, name, key);
+	timer_set_deferrable(timer);
+}
+EXPORT_SYMBOL_GPL(setup_deferrable_timer_on_stack_key);
+
 /**
  * init_timer_key - initialize a timer
  * @timer: the timer to be initialized
@@ -679,12 +697,8 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
 	cpu = smp_processor_id();
 
 #if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
-	if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu)) {
-		int preferred_cpu = get_nohz_load_balancer();
-
-		if (preferred_cpu >= 0)
-			cpu = preferred_cpu;
-	}
+	if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu))
+		cpu = get_nohz_timer_target();
 #endif
 	new_base = per_cpu(tvec_bases, cpu);
 
@@ -750,13 +764,18 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
 	unsigned long expires_limit, mask;
 	int bit;
 
-	expires_limit = expires + timer->slack;
+	expires_limit = expires;
 
-	if (timer->slack < 0) /* auto slack: use 0.4% */
-		expires_limit = expires + (expires - jiffies)/256;
+	if (timer->slack >= 0) {
+		expires_limit = expires + timer->slack;
+	} else {
+		unsigned long now = jiffies;
 
+		/* No slack, if already expired else auto slack 0.4% */
+		if (time_after(expires, now))
+			expires_limit = expires + (expires - now)/256;
+	}
 	mask = expires ^ expires_limit;
-
 	if (mask == 0)
 		return expires;
 
@@ -1284,7 +1303,6 @@ void run_local_timers(void)
 {
 	hrtimer_run_queues();
 	raise_softirq(TIMER_SOFTIRQ);
-	softlockup_tick();
 }
 
 /*
@@ -1679,11 +1697,14 @@ static int __cpuinit timer_cpu_notify(struct notifier_block *self,
 				unsigned long action, void *hcpu)
 {
 	long cpu = (long)hcpu;
+	int err;
+
 	switch(action) {
 	case CPU_UP_PREPARE:
 	case CPU_UP_PREPARE_FROZEN:
-		if (init_timers_cpu(cpu) < 0)
-			return NOTIFY_BAD;
+		err = init_timers_cpu(cpu);
+		if (err < 0)
+			return notifier_from_errno(err);
 		break;
 #ifdef CONFIG_HOTPLUG_CPU
 	case CPU_DEAD:
@@ -1709,7 +1730,7 @@ void __init init_timers(void)
 
 	init_timer_stats();
 
-	BUG_ON(err == NOTIFY_BAD);
+	BUG_ON(err != NOTIFY_OK);
 	register_cpu_notifier(&timers_nb);
 	open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
 }
@@ -1742,3 +1763,25 @@ unsigned long msleep_interruptible(unsigned int msecs)
 }
 
 EXPORT_SYMBOL(msleep_interruptible);
+
+static int __sched do_usleep_range(unsigned long min, unsigned long max)
+{
+	ktime_t kmin;
+	unsigned long delta;
+
+	kmin = ktime_set(0, min * NSEC_PER_USEC);
+	delta = (max - min) * NSEC_PER_USEC;
+	return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL);
+}
+
+/**
+ * usleep_range - Drop in replacement for udelay where wakeup is flexible
+ * @min: Minimum time in usecs to sleep
+ * @max: Maximum time in usecs to sleep
+ */
+void usleep_range(unsigned long min, unsigned long max)
+{
+	__set_current_state(TASK_UNINTERRUPTIBLE);
+	do_usleep_range(min, max);
+}
+EXPORT_SYMBOL(usleep_range);