1 files changed, 22 insertions, 4 deletions

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index b854a895591e..825b4c00fe44 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)
@@ -188,7 +195,7 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
  * Called either from the idle loop or from irq_exit() when an idle period was
  * just interrupted by an interrupt which did not cause a reschedule.
  */
-void tick_nohz_stop_sched_tick(void)
+void tick_nohz_stop_sched_tick(int inidle)
 {
         unsigned long seq, last_jiffies, next_jiffies, delta_jiffies, flags;
         struct tick_sched *ts;
@@ -217,6 +224,11 @@ void tick_nohz_stop_sched_tick(void)
         if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
                 goto end;
 
+        if (!inidle && !ts->inidle)
+                goto end;
+
+        ts->inidle = 1;
+
         if (need_resched())
                 goto end;
 
@@ -228,6 +240,7 @@ void tick_nohz_stop_sched_tick(void)
                                local_softirq_pending());
                         ratelimit++;
                 }
+                goto end;
         }
 
         ts->idle_calls++;
@@ -276,6 +289,7 @@ void tick_nohz_stop_sched_tick(void)
                         ts->tick_stopped = 1;
                         ts->idle_jiffies = last_jiffies;
                         rcu_enter_nohz();
+                        sched_clock_tick_stop(cpu);
                 }
 
                 /*
@@ -364,17 +378,21 @@ void tick_nohz_restart_sched_tick(void)
         local_irq_disable();
         tick_nohz_stop_idle(cpu);
 
-        if (!ts->tick_stopped) {
+        if (!ts->inidle || !ts->tick_stopped) {
+                ts->inidle = 0;
                 local_irq_enable();
                 return;
         }
 
+        ts->inidle = 0;
+
         rcu_exit_nohz();
 
         /* Update jiffies first */
         select_nohz_load_balancer(0);
         now = ktime_get();
         tick_do_update_jiffies64(now);
+        sched_clock_tick_start(cpu);
         cpu_clear(cpu, nohz_cpu_mask);
 
         /*