Let's change the worker state between free/running only when it's
necessary. This can reduce some lock contension.
Signed-off-by: Hao Xu <haoxu@xxxxxxxxxxxxxxxxx>
---
fs/io-wq.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 097ea598bfe5..377c3e42a491 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -434,12 +434,11 @@ static void io_wqe_dec_running(struct io_worker *worker)
*/
static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
struct io_wq_work *work)
- __must_hold(wqe->lock)
{
- if (worker->flags & IO_WORKER_F_FREE) {
- worker->flags &= ~IO_WORKER_F_FREE;
- hlist_nulls_del_init_rcu(&worker->nulls_node);
- }
+ raw_spin_lock(&wqe->lock);
+ worker->flags &= ~IO_WORKER_F_FREE;
+ hlist_nulls_del_init_rcu(&worker->nulls_node);
+ raw_spin_unlock(&wqe->lock);
}
/*
@@ -587,13 +586,10 @@ static void io_worker_handle_work(struct io_worker *worker, struct io_wqe_acct *
* clear the stalled flag.
*/
work = io_get_next_work(acct, worker, needs_lock);
- if (work) {
- raw_spin_lock(&wqe->lock);
+ if (work && (worker->flags & IO_WORKER_F_FREE))
__io_worker_busy(wqe, worker, work);
- raw_spin_unlock(&wqe->lock);
- } else {
+ else if (!work)
break;
- }
io_assign_current_work(worker, work);
__set_current_state(TASK_RUNNING);
--
2.24.4
