2 files changed, 27 insertions, 21 deletions

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 8ff15e5d486b..f5f793d92415 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -131,7 +131,7 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
 {
         enum hrtimer_restart res = HRTIMER_NORESTART;
 
-        write_seqlock_irq(&xtime_lock);
+        write_seqlock(&xtime_lock);
 
         switch (time_state) {
         case TIME_OK:
@@ -164,7 +164,7 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
         }
         update_vsyscall(&xtime, clock);
 
-        write_sequnlock_irq(&xtime_lock);
+        write_sequnlock(&xtime_lock);
 
         return res;
 }
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 342fc9ccab46..8f3fc2582d38 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -247,7 +247,7 @@ void tick_nohz_stop_sched_tick(int inidle)
         if (need_resched())
                 goto end;
 
-        if (unlikely(local_softirq_pending())) {
+        if (unlikely(local_softirq_pending() && cpu_online(cpu))) {
                 static int ratelimit;
 
                 if (ratelimit < 10) {
@@ -282,8 +282,31 @@ void tick_nohz_stop_sched_tick(int inidle)
         /* Schedule the tick, if we are at least one jiffie off */
         if ((long)delta_jiffies >= 1) {
 
+                /*
+                * calculate the expiry time for the next timer wheel
+                * timer
+                */
+                expires = ktime_add_ns(last_update, tick_period.tv64 *
+                                   delta_jiffies);
+
+                /*
+                 * If this cpu is the one which updates jiffies, then
+                 * give up the assignment and let it be taken by the
+                 * cpu which runs the tick timer next, which might be
+                 * this cpu as well. If we don't drop this here the
+                 * jiffies might be stale and do_timer() never
+                 * invoked.
+                 */
+                if (cpu == tick_do_timer_cpu)
+                        tick_do_timer_cpu = TICK_DO_TIMER_NONE;
+
                 if (delta_jiffies > 1)
                         cpu_set(cpu, nohz_cpu_mask);
+
+                /* Skip reprogram of event if its not changed */
+                if (ts->tick_stopped && ktime_equal(expires, dev->next_event))
+                        goto out;
+
                 /*
                  * nohz_stop_sched_tick can be called several times before
                  * the nohz_restart_sched_tick is called. This happens when
@@ -306,17 +329,6 @@ void tick_nohz_stop_sched_tick(int inidle)
                         rcu_enter_nohz();
                 }
 
-                /*
-                 * If this cpu is the one which updates jiffies, then
-                 * give up the assignment and let it be taken by the
-                 * cpu which runs the tick timer next, which might be
-                 * this cpu as well. If we don't drop this here the
-                 * jiffies might be stale and do_timer() never
-                 * invoked.
-                 */
-                if (cpu == tick_do_timer_cpu)
-                        tick_do_timer_cpu = TICK_DO_TIMER_NONE;
-
                 ts->idle_sleeps++;
 
                 /*
@@ -332,12 +344,7 @@ void tick_nohz_stop_sched_tick(int inidle)
                         goto out;
                 }
 
-                /*
-                 * calculate the expiry time for the next timer wheel
-                 * timer
-                 */
-                expires = ktime_add_ns(last_update, tick_period.tv64 *
-                                       delta_jiffies);
+                /* Mark expiries */
                 ts->idle_expires = expires;
 
                 if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
@@ -681,7 +688,6 @@ void tick_setup_sched_timer(void)
          */
         hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
         ts->sched_timer.function = tick_sched_timer;
-        ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU;
 
         /* Get the next period (per cpu) */
         hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());