From 8f172181f24bb5df7675225d9b5b66d059613f50 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 8 Feb 2024 14:11:56 -1000 Subject: [PATCH] workqueue: Implement workqueue_set_min_active() Since 5797b1c18919 ("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: Tejun Heo --- include/linux/workqueue.h | 2 ++ kernel/workqueue.c | 27 +++++++++++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 4ba33cf07f11..1565bab9edc8 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -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); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index ddcdeb7b9f26..4950bfc2cdcc 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -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 *