1 files changed, 12 insertions, 2 deletions

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index b854a895591e..942fc7c85283 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -48,6 +48,13 @@ static void tick_do_update_jiffies64(ktime_t now)
         unsigned long ticks = 0;
         ktime_t delta;
 
+        /*
+         * Do a quick check without holding xtime_lock:
+         */
+        delta = ktime_sub(now, last_jiffies_update);
+        if (delta.tv64 < tick_period.tv64)
+                return;
+
         /* Reevalute with xtime_lock held */
         write_seqlock(&xtime_lock);
 
@@ -133,8 +140,6 @@ void tick_nohz_update_jiffies(void)
         if (!ts->tick_stopped)
                 return;
 
-        touch_softlockup_watchdog();
-
         cpu_clear(cpu, nohz_cpu_mask);
         now = ktime_get();
         ts->idle_waketime = now;
@@ -142,6 +147,8 @@ void tick_nohz_update_jiffies(void)
         local_irq_save(flags);
         tick_do_update_jiffies64(now);
         local_irq_restore(flags);
+
+        touch_softlockup_watchdog();
 }
 
 void tick_nohz_stop_idle(int cpu)
@@ -228,6 +235,7 @@ void tick_nohz_stop_sched_tick(void)
                                local_softirq_pending());
                         ratelimit++;
                 }
+                goto end;
         }
 
         ts->idle_calls++;
@@ -276,6 +284,7 @@ void tick_nohz_stop_sched_tick(void)
                         ts->tick_stopped = 1;
                         ts->idle_jiffies = last_jiffies;
                         rcu_enter_nohz();
+                        sched_clock_tick_stop(cpu);
                 }
 
                 /*
@@ -375,6 +384,7 @@ void tick_nohz_restart_sched_tick(void)
         select_nohz_load_balancer(0);
         now = ktime_get();
         tick_do_update_jiffies64(now);
+        sched_clock_tick_start(cpu);
         cpu_clear(cpu, nohz_cpu_mask);
 
         /*