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: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2007-05-09 02:34:15 -07:00 committed by Linus Torvalds
parent c12920d190
commit 06ba38a9a0

View File

@ -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;