Revert "tick/common: Make tick_periodic() check for missing ticks"

#include <linux/profile.h>

#include <linux/sched.h>

#include <linux/module.h>

#include <linux/sched/clock.h>

#include <trace/events/power.h>

#include <asm/irq_regs.h>

static void tick_periodic(int cpu)

{

	if (tick_do_timer_cpu == cpu) {

		/*

		 * Use running_clock() as reference to check for missing ticks.

		 */

		static ktime_t last_update;

		ktime_t now;

		int ticks = 1;

		now = ns_to_ktime(running_clock());

		write_seqlock(&jiffies_lock);

		if (last_update) {

			u64 delta = ktime_sub(now, last_update);

			/*

			 * Check for eventually missed ticks

			 *

			 * There is likely a persistent delta between

			 * last_update and tick_next_period. So they are

			 * updated separately.

			 */

			if (delta >= 2 * tick_period) {

				s64 period = ktime_to_ns(tick_period);

				ticks = ktime_divns(delta, period);

			}

			last_update = ktime_add(last_update,

						ticks * tick_period);

		} else {

			last_update = now;

		}

		/* Keep track of the next tick event */

		tick_next_period = ktime_add(tick_next_period,

					     ticks * tick_period);

		do_timer(ticks);

		tick_next_period = ktime_add(tick_next_period, tick_period);

		do_timer(1);

		write_sequnlock(&jiffies_lock);

		update_wall_time();

	}