workqueue: void unneeded requeuing the pwq in rescuer thread

008847f66c3 ("workqueue: allow rescuer thread to do more work.") made the rescuer worker requeue the pwq immediately if there may be more work items which need rescuing instead of waiting for the next mayday timer expiration. Unfortunately, it checks only whether the pool needs help from rescuers, but it doesn't check whether the pwq has work items in the pool (the real reason that this rescuer can help for the pool). The patch adds the check and void unneeded requeuing.

Lai Jiangshan committed 6 years ago

Commit 4f3f4cf1 parent a9b8a981 file · +1 −1Browse files

Unified · Split

kernel/workqueue.c+1−1

@@ -2530,7 +2530,7 @@ repeat: · 2529 unmodified lines
2530	2530	* being used to relieve memory pressure, don't
2531	2531	* incur MAYDAY_INTERVAL delay inbetween.
2532	2532	*/
2533		− if (need_to_create_worker(pool)) {
	2533	+ if (pwq->nr_active && need_to_create_worker(pool)) {
2534	2534	raw_spin_lock(&wq_mayday_lock);
2535	2535	/*
2536	2536	* Queue iff we aren't racing destruction