Commit 974271c4 authored by Tejun Heo's avatar Tejun Heo
Browse files

workqueue: don't use WQ_HIGHPRI for unbound workqueues 



Unbound wqs aren't concurrency-managed and try to execute work items
as soon as possible.  This is currently achieved by implicitly setting
%WQ_HIGHPRI on all unbound workqueues; however, WQ_HIGHPRI
implementation is about to be restructured and this usage won't be
valid anymore.

Add an explicit chain-wakeup path for unbound workqueues in
process_one_work() instead of piggy backing on %WQ_HIGHPRI.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 918227bb

kernel/workqueue.c

+11 −7
Original line number Diff line number Diff line
@@ -580,6 +580,10 @@ static bool __need_more_worker(struct global_cwq *gcwq) 
/*

 * Need to wake up a worker?  Called from anything but currently

 * running workers.

 *

 * Note that, because unbound workers never contribute to nr_running, this

 * function will always return %true for unbound gcwq as long as the

 * worklist isn't empty.

 */

static bool need_more_worker(struct global_cwq *gcwq)

{
@@ -1867,6 +1871,13 @@ __acquires(&gcwq->lock) 
	if (unlikely(cpu_intensive))

		worker_set_flags(worker, WORKER_CPU_INTENSIVE, true);



	/*

	 * Unbound gcwq isn't concurrency managed and work items should be

	 * executed ASAP.  Wake up another worker if necessary.

	 */

	if ((worker->flags & WORKER_UNBOUND) && need_more_worker(gcwq))

		wake_up_worker(gcwq);



	spin_unlock_irq(&gcwq->lock);



	work_clear_pending(work);
@@ -2984,13 +2995,6 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, 
	if (flags & WQ_MEM_RECLAIM)

		flags |= WQ_RESCUER;



	/*

	 * Unbound workqueues aren't concurrency managed and should be

	 * dispatched to workers immediately.

	 */

	if (flags & WQ_UNBOUND)

		flags |= WQ_HIGHPRI;



	max_active = max_active ?: WQ_DFL_ACTIVE;

	max_active = wq_clamp_max_active(max_active, flags, wq->name);

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