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.
Unified · Split
| @@ -2530,7 +2530,7 @@ repeat: · 2529 unmodified lines | |||
| 2530 | * being used to relieve memory pressure, don't | 2530 | * being used to relieve memory pressure, don't |
| 2531 | * incur MAYDAY_INTERVAL delay inbetween. | 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 | raw_spin_lock(&wq_mayday_lock); | 2534 | raw_spin_lock(&wq_mayday_lock); |
| 2535 | /* | 2535 | /* |
| 2536 | * Queue iff we aren't racing destruction | 2536 | * Queue iff we aren't racing destruction |