Commit 8f172181 authored by Tejun Heo's avatar Tejun Heo
Browse files

workqueue: Implement workqueue_set_min_active() 



Since 5797b1c1 ("workqueue: Implement system-wide nr_active enforcement
for unbound workqueues"), unbound workqueues have separate min_active which
sets the number of interdependent work items that can be handled. This value
is currently initialized to WQ_DFL_MIN_ACTIVE which is 8. This isn't high
enough for some users, let's add an interface to adjust the setting.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 516d3dc9

include/linux/workqueue.h

+2 −0
Original line number Diff line number Diff line
@@ -553,6 +553,8 @@ extern bool flush_rcu_work(struct rcu_work *rwork); 


extern void workqueue_set_max_active(struct workqueue_struct *wq,

				     int max_active);

extern void workqueue_set_min_active(struct workqueue_struct *wq,

				     int min_active);

extern struct work_struct *current_work(void);

extern bool current_is_workqueue_rescuer(void);

extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);

kernel/workqueue.c

+27 −0
Original line number Diff line number Diff line
@@ -5629,6 +5629,33 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) 
}

EXPORT_SYMBOL_GPL(workqueue_set_max_active);



/**

 * workqueue_set_min_active - adjust min_active of an unbound workqueue

 * @wq: target unbound workqueue

 * @min_active: new min_active value

 *

 * Set min_active of an unbound workqueue. Unlike other types of workqueues, an

 * unbound workqueue is not guaranteed to be able to process max_active

 * interdependent work items. Instead, an unbound workqueue is guaranteed to be

 * able to process min_active number of interdependent work items which is

 * %WQ_DFL_MIN_ACTIVE by default.

 *

 * Use this function to adjust the min_active value between 0 and the current

 * max_active.

 */

void workqueue_set_min_active(struct workqueue_struct *wq, int min_active)

{

	/* min_active is only meaningful for non-ordered unbound workqueues */

	if (WARN_ON((wq->flags & (WQ_BH | WQ_UNBOUND | __WQ_ORDERED)) !=

		    WQ_UNBOUND))

		return;



	mutex_lock(&wq->mutex);

	wq->saved_min_active = clamp(min_active, 0, wq->saved_max_active);

	wq_adjust_max_active(wq);

	mutex_unlock(&wq->mutex);

}



/**

 * current_work - retrieve %current task's work struct

 *