From: Pavel Begunkov Date: Mon, 30 Dec 2019 18:24:46 +0000 (+0300) Subject: io_uring: optimise commit_sqring() for common case X-Git-Tag: for-5.6/io_uring-vfs-2020-01-29~34 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=caf582c652feccd42c50923f0467c4f2dcef279e;p=linux-block.git io_uring: optimise commit_sqring() for common case It should be pretty rare to not submitting anything when there is something in the ring. No need to keep heuristics for this case. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- diff --git a/fs/io_uring.c b/fs/io_uring.c index 3398f4052ec0..8613eae31f4c 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4501,14 +4501,12 @@ static void io_commit_sqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; - if (ctx->cached_sq_head != READ_ONCE(rings->sq.head)) { - /* - * Ensure any loads from the SQEs are done at this point, - * since once we write the new head, the application could - * write new data to them. - */ - smp_store_release(&rings->sq.head, ctx->cached_sq_head); - } + /* + * Ensure any loads from the SQEs are done at this point, + * since once we write the new head, the application could + * write new data to them. + */ + smp_store_release(&rings->sq.head, ctx->cached_sq_head); } /*