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From: Jens Axboe <axboe@kernel.dk>
To: io-uring@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 1/3] io_uring/io-wq: don't grab wq->lock for worker activation
Date: Wed,  9 Aug 2023 13:43:04 -0600	[thread overview]
Message-ID: <20230809194306.170979-2-axboe@kernel.dk> (raw)
In-Reply-To: <20230809194306.170979-1-axboe@kernel.dk>

The worker free list is RCU protected, and checks for workers going away
when iterating it. There's no need to hold the wq->lock around the
lookup.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 io_uring/io-wq.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c
index 399e9a15c38d..3e7025b9e0dd 100644
--- a/io_uring/io-wq.c
+++ b/io_uring/io-wq.c
@@ -909,13 +909,10 @@ void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
 	clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
 	raw_spin_unlock(&acct->lock);
 
-	raw_spin_lock(&wq->lock);
 	rcu_read_lock();
 	do_create = !io_wq_activate_free_worker(wq, acct);
 	rcu_read_unlock();
 
-	raw_spin_unlock(&wq->lock);
-
 	if (do_create && ((work_flags & IO_WQ_WORK_CONCURRENT) ||
 	    !atomic_read(&acct->nr_running))) {
 		bool did_create;
-- 
2.40.1


  reply	other threads:[~2023-08-09 19:43 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-09 19:43 [PATCHSET 0/3] io-wq locking improvements Jens Axboe
2023-08-09 19:43 ` Jens Axboe [this message]
2023-08-09 19:43 ` [PATCH 2/3] io_uring/io-wq: reduce frequency of acct->lock acquisitions Jens Axboe
2023-08-09 19:43 ` [PATCH 3/3] io_uring/io-wq: don't gate worker wake up success on wake_up_process() Jens Axboe
2023-08-11  4:00 ` [PATCHSET 0/3] io-wq locking improvements Hao Xu
2023-08-11 16:36   ` Jens Axboe

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