workqueue: defer the worker wakeup outside pool->lock in __queue_work()

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__queue_work() is the enqueue hot path: it inserts the work item and
calls kick_pool() while holding pool->lock. kick_pool() ends in a
wakeup, which takes the target task's rq->lock, so rq->lock nests under
pool->lock on every enqueue that wakes a worker on a contended unbound
pool.

Use kick_pool_pick() to select and claim the worker under pool->lock and
issue the wakeup with wake_up_process() right after dropping the lock.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

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Breno Leitao 2026-06-26 02:57:54 -07:00 • committed by Tejun Heo

parent 1ad5dcee7c

commit d070f2916a

1 changed files with 4 additions and 1 deletions

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kernel/workqueue.c

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