+/*
+ * When NOHZ is enabled and the tick is stopped, we need to kick the
+ * tick timer from irq_enter() so that the jiffies update is kept
+ * alive during long running softirqs. That's ugly as hell, but
+ * correctness is key even if we need to fix the offending softirq in
+ * the first place.
+ *
+ * Note, this is different to tick_nohz_restart. We just kick the
+ * timer and do not touch the other magic bits which need to be done
+ * when idle is left.
+ */
+static void tick_nohz_kick_tick(int cpu)
+{
+ struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+ ktime_t delta, now;
+
+ if (!ts->tick_stopped)
+ return;
+
+ /*
+ * Do not touch the tick device, when the next expiry is either
+ * already reached or less/equal than the tick period.
+ */
+ now = ktime_get();
+ delta = ktime_sub(hrtimer_get_expires(&ts->sched_timer), now);
+ if (delta.tv64 <= tick_period.tv64)
+ return;
+
+ tick_nohz_restart(ts, now);
+}
+