Commit 7255cd89 authored by Olivier Langlois's avatar Olivier Langlois Committed by Jens Axboe
Browse files

io_uring: micro optimization of __io_sq_thread() condition 



reverse the order of the element evaluation in an if statement.

for many users that are not using iopoll, the iopoll_list will always
evaluate to false after having made a memory access whereas to_submit is
very likely already loaded in a register.

Signed-off-by: default avatarOlivier Langlois <olivier@trillion01.com>
Reviewed-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/052ca60b5c49e7439e4b8bd33bfab4a09d36d3d6.1722374371.git.olivier@trillion01.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a8edbb42

io_uring/sqpoll.c

+1 −1
Original line number Diff line number Diff line
@@ -176,7 +176,7 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries) 
	if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE)

		to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE;



	if (!wq_list_empty(&ctx->iopoll_list) || to_submit) {

	if (to_submit || !wq_list_empty(&ctx->iopoll_list)) {

		const struct cred *creds = NULL;



		if (ctx->sq_creds != current_cred())