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Commit 6ba9b346 authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
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[PATCH] NOHZ: Fix RCU handling 



When a CPU is needed for RCU the tick has to continue even when it was
stopped before.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2aa6eb31

kernel/time/tick-sched.c

+4 −4
Original line number Diff line number Diff line
@@ -191,19 +191,19 @@ void tick_nohz_stop_sched_tick(void) 
	next_jiffies = get_next_timer_interrupt(last_jiffies);

	delta_jiffies = next_jiffies - last_jiffies;



	if (rcu_needs_cpu(cpu))

		delta_jiffies = 1;

	/*

	 * Do not stop the tick, if we are only one off

	 * or if the cpu is required for rcu

	 */

	if (!ts->tick_stopped && (delta_jiffies == 1 || rcu_needs_cpu(cpu)))

	if (!ts->tick_stopped && delta_jiffies == 1)

		goto out;



	/* Schedule the tick, if we are at least one jiffie off */

	if ((long)delta_jiffies >= 1) {



		if (rcu_needs_cpu(cpu))

			delta_jiffies = 1;

		else

		if (delta_jiffies > 1)

			cpu_set(cpu, nohz_cpu_mask);

		/*

		 * nohz_stop_sched_tick can be called several times before