Commit e0b23d99 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: optimise ltimeout for inline execution 



At one point in time we had an optimisation that would not spin up a
linked timeout timer when the master request successfully completes
inline (during the first nowait execution attempt). We somehow lost it,
so this patch restores it back.

Note, that it's fine using io_arm_ltimeout() after the io_issue_sqe()
completes the request because of delayed completion, but that that adds
unwanted overhead.

Reported-by: default avatarChristian Mazakas <christian.mazakas@gmail.com>
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8bf69c2a4beec14c565c85c86edb871ca8b8bcc8.1701390926.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9b43ef3d

io_uring/io_uring.c

+9 −10
Original line number Diff line number Diff line
@@ -1902,14 +1902,15 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags) 
		return 0;

	}



	if (ret != IOU_ISSUE_SKIP_COMPLETE)

		return ret;

	if (ret == IOU_ISSUE_SKIP_COMPLETE) {

		ret = 0;

		io_arm_ltimeout(req);



		/* If the op doesn't have a file, we're not polling for it */

		if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue)

			io_iopoll_req_issued(req, issue_flags);



	return 0;

	}

	return ret;

}



int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts)
@@ -2080,9 +2081,7 @@ static inline void io_queue_sqe(struct io_kiocb *req) 
	 * We async punt it if the file wasn't marked NOWAIT, or if the file

	 * doesn't support non-blocking read/write attempts

	 */

	if (likely(!ret))

		io_arm_ltimeout(req);

	else

	if (unlikely(ret))

		io_queue_async(req, ret);

}