Commit f36ba6cf authored Jan 05, 2023 by Pavel Begunkov Committed by Jens Axboe Jan 29, 2023

io_uring: don't iterate cq wait fast path

Task work runners keep running until all queues tw items are exhausted.
It's also rare for defer tw to queue normal tw and vise versa. Taking it
into account, there is only a dim chance that further iterating the
io_cqring_wait() fast path will get us anything and so we can remove
the loop there.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1f9565726661266abaa5d921e97433c831759ecf.1672916894.git.asml.silence@gmail.com

Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 0c4fe008

io_uring/io_uring.c

+8 −10

Original line number	Diff line number	Diff line
		@@ -2510,18 +2510,16 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,

		if (!io_allowed_run_tw(ctx))
		return -EEXIST;

		do {
		/* always run at least 1 task work to process local work */
		ret = io_run_task_work_ctx(ctx);
		if (!llist_empty(&ctx->work_llist)) {
		ret = io_run_local_work(ctx);
		if (ret < 0)
		return ret;
		}
		io_run_task_work();
		io_cqring_overflow_flush(ctx);

		/* if user messes with these they will just get an early return */
		if (__io_cqring_events_user(ctx) >= min_events)
		return 0;
		} while (ret > 0);

		if (sig) {
		#ifdef CONFIG_COMPAT