Commit f05b558d authored Jun 03, 2014 by Lai Jiangshan Committed by Tejun Heo Jun 19, 2014

workqueue: clear POOL_DISASSOCIATED in rebind_workers()



The commit a9ab775b ("workqueue: directly restore CPU affinity of
workers from CPU_ONLINE") moved the pool->lock into rebind_workers()
without also moving "pool->flags &= ~POOL_DISASSOCIATED".

There is nothing wrong with "pool->flags &= ~POOL_DISASSOCIATED" not
being moved together, but there isn't any benefit either. We move it
into rebind_workers() and achieve these benefits:

1) Better readability.  POOL_DISASSOCIATED is cleared in
   rebind_workers() as expected.

2) When POOL_DISASSOCIATED is cleared, we can ensure that all the
   running workers of the pool are on the local CPU (pool->cpu).

tj: Cosmetic updates to the code and description.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

parent fb009e3a

kernel/workqueue.c

+3 −7

Original line number	Diff line number	Diff line
		@@ -4542,6 +4542,7 @@ static void rebind_workers(struct worker_pool *pool)
		pool->attrs->cpumask) < 0);

		spin_lock_irq(&pool->lock);
		pool->flags &= ~POOL_DISASSOCIATED;

		for_each_pool_worker(worker, pool) {
		unsigned int worker_flags = worker->flags;
		@@ -4643,15 +4644,10 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb,
		for_each_pool(pool, pi) {
		mutex_lock(&pool->attach_mutex);

		if (pool->cpu == cpu) {
		spin_lock_irq(&pool->lock);
		pool->flags &= ~POOL_DISASSOCIATED;
		spin_unlock_irq(&pool->lock);

		if (pool->cpu == cpu)
		rebind_workers(pool);
		} else if (pool->cpu < 0) {
		else if (pool->cpu < 0)
		restore_unbound_workers_cpumask(pool, cpu);
		}

		mutex_unlock(&pool->attach_mutex);
		}

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