From eb0089d629ba413ebf820733ad11b4b2bed45514 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 15 Dec 2021 22:08:49 +0000 Subject: [PATCH] io_uring: single shot poll removal optimisation We don't need to poll oneshot request if we've got a desired mask in io_poll_wake(), task_work will clean it up correctly, but as we already hold a wq spinlock, we can remove ourselves and save on additional spinlocking in io_poll_remove_entries(). Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/ee170a344a18c9ef36b554d806c64caadfd61c31.1639605189.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index a36eb6060e7e..206066b59b62 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5568,8 +5568,14 @@ static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, if (mask && !(mask & poll->events)) return 0; - if (io_poll_get_ownership(req)) + if (io_poll_get_ownership(req)) { + /* optional, saves extra locking for removal in tw handler */ + if (mask && poll->events & EPOLLONESHOT) { + list_del_init(&poll->wait.entry); + poll->head = NULL; + } __io_poll_execute(req, mask); + } return 1; }