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Commit cc3ce517 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
Browse files

rcu: Start RCU kthreads in TASK_INTERRUPTIBLE state 



Upon creation, kthreads are in TASK_UNINTERRUPTIBLE state, which can
result in softlockup warnings.  Because some of RCU's kthreads can
legitimately be idle indefinitely, start them in TASK_INTERRUPTIBLE
state in order to avoid those warnings.

Suggested-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: default avatarYinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 08bca60a

kernel/rcutree.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -1648,6 +1648,7 @@ static int __cpuinit rcu_spawn_one_cpu_kthread(int cpu) 
	if (IS_ERR(t))

	if (IS_ERR(t))

		return PTR_ERR(t);

		return PTR_ERR(t);

	kthread_bind(t, cpu);

	kthread_bind(t, cpu);

	set_task_state(t, TASK_INTERRUPTIBLE);

	per_cpu(rcu_cpu_kthread_cpu, cpu) = cpu;

	per_cpu(rcu_cpu_kthread_cpu, cpu) = cpu;

	WARN_ON_ONCE(per_cpu(rcu_cpu_kthread_task, cpu) != NULL);

	WARN_ON_ONCE(per_cpu(rcu_cpu_kthread_task, cpu) != NULL);

	per_cpu(rcu_cpu_kthread_task, cpu) = t;

	per_cpu(rcu_cpu_kthread_task, cpu) = t;
@@ -1755,6 +1756,7 @@ static int __cpuinit rcu_spawn_one_node_kthread(struct rcu_state *rsp, 
		if (IS_ERR(t))

		if (IS_ERR(t))

			return PTR_ERR(t);

			return PTR_ERR(t);

		raw_spin_lock_irqsave(&rnp->lock, flags);

		raw_spin_lock_irqsave(&rnp->lock, flags);

		set_task_state(t, TASK_INTERRUPTIBLE);

		rnp->node_kthread_task = t;

		rnp->node_kthread_task = t;

		raw_spin_unlock_irqrestore(&rnp->lock, flags);

		raw_spin_unlock_irqrestore(&rnp->lock, flags);

		sp.sched_priority = 99;

		sp.sched_priority = 99;

kernel/rcutree_plugin.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -1295,6 +1295,7 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, 
	if (IS_ERR(t))

	if (IS_ERR(t))

		return PTR_ERR(t);

		return PTR_ERR(t);

	raw_spin_lock_irqsave(&rnp->lock, flags);

	raw_spin_lock_irqsave(&rnp->lock, flags);

	set_task_state(t, TASK_INTERRUPTIBLE);

	rnp->boost_kthread_task = t;

	rnp->boost_kthread_task = t;

	raw_spin_unlock_irqrestore(&rnp->lock, flags);

	raw_spin_unlock_irqrestore(&rnp->lock, flags);

	sp.sched_priority = RCU_KTHREAD_PRIO;

	sp.sched_priority = RCU_KTHREAD_PRIO;