Commit 3de5e884 authored Jun 03, 2014 by Lai Jiangshan Committed by Tejun Heo Jul 01, 2014

workqueue: clear POOL_DISASSOCIATED in rebind_workers()



a9ab775b ("workqueue: directly restore CPU affinity of workers
from CPU_ONLINE") moved pool locking into rebind_workers() but left
"pool->flags &= ~POOL_DISASSOCIATED" in workqueue_cpu_up_callback().

There is nothing necessarily wrong with it, but there is no benefit
either.  Let's move it into rebind_workers() and achieve the following
benefits:

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

  2) we can guarantee that, when POOL_DISASSOCIATED is clear, the
     running workers of the pool are on the local CPU (pool->cpu).

tj: Minor description update.

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

parent 92b69f50

kernel/workqueue.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -4535,6 +4535,7 @@ 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;
		@@ -4637,10 +4638,6 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb,
		mutex_lock(&pool->attach_mutex);

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

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

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