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Commit 06ba38a9 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

workqueues: shift kthread_bind() from CPU_UP_PREPARE to CPU_ONLINE 



CPU_UP_PREPARE binds cwq->thread to the new CPU.  So CPU_UP_CANCELED tries to
wake up the task which is bound to the failed CPU.

With this patch we don't bind cwq->thread until CPU becomes online.  The first
wake_up() after kthread_create() is a bit special, make a simple helper for
that.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c12920d1

kernel/workqueue.c

+15 −8
Original line number Diff line number Diff line
@@ -668,15 +668,21 @@ static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) 


	cwq->thread = p;

	cwq->should_stop = 0;

	if (!is_single_threaded(wq))

		kthread_bind(p, cpu);



	if (is_single_threaded(wq) || cpu_online(cpu))

		wake_up_process(p);



	return 0;

}



static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)

{

	struct task_struct *p = cwq->thread;



	if (p != NULL) {

		if (cpu >= 0)

			kthread_bind(p, cpu);

		wake_up_process(p);

	}

}



struct workqueue_struct *__create_workqueue(const char *name,

					    int singlethread, int freezeable)

{
@@ -702,6 +708,7 @@ struct workqueue_struct *__create_workqueue(const char *name, 
	if (singlethread) {

		cwq = init_cpu_workqueue(wq, singlethread_cpu);

		err = create_workqueue_thread(cwq, singlethread_cpu);

		start_workqueue_thread(cwq, -1);

	} else {

		mutex_lock(&workqueue_mutex);

		list_add(&wq->list, &workqueues);
@@ -711,6 +718,7 @@ struct workqueue_struct *__create_workqueue(const char *name, 
			if (err || !cpu_online(cpu))

				continue;

			err = create_workqueue_thread(cwq, cpu);

			start_workqueue_thread(cwq, cpu);

		}

		mutex_unlock(&workqueue_mutex);

	}
@@ -808,12 +816,11 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, 
			return NOTIFY_BAD;



		case CPU_ONLINE:

			wake_up_process(cwq->thread);

			start_workqueue_thread(cwq, cpu);

			break;



		case CPU_UP_CANCELED:

			if (cwq->thread)

				wake_up_process(cwq->thread);

			start_workqueue_thread(cwq, -1);

		case CPU_DEAD:

			cleanup_workqueue_thread(cwq, cpu);

			break;