From 7255cd894539a96fefab9180185d268647c7341b Mon Sep 17 00:00:00 2001 From: Olivier Langlois Date: Tue, 30 Jul 2024 16:56:06 -0400 Subject: [PATCH] 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: Olivier Langlois Reviewed-by: Pavel Begunkov Link: https://lore.kernel.org/r/052ca60b5c49e7439e4b8bd33bfab4a09d36d3d6.1722374371.git.olivier@trillion01.com Signed-off-by: Jens Axboe --- io_uring/sqpoll.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 3b50dc9586d1..e545bf240d35 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -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())