Commit a538be5b authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: optimise io_free_batch_list 



We do several req->flags checks in the fast path of
io_free_batch_list(). One explicit check of REQ_F_REFCOUNT, and two
other hidden in io_queue_next() and io_dismantle_req(). Moreover, there
is a io_req_put_rsrc_locked() call in between, so there is no hope
req->flags will be preserved in registers.

All those flags if not a slow path than definitely a slower path, so
put them all under a single flags mask check and save several mem
reloads and ifs.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0fb493f73f2009aea395c570c2932fecaa4e1244.1647897811.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7819a1f6

fs/io_uring.c

+14 −6
Original line number Diff line number Diff line
@@ -113,6 +113,9 @@ 
#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \

				REQ_F_POLLED | REQ_F_CREDS | REQ_F_ASYNC_DATA)



#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\

				 IO_REQ_CLEAN_FLAGS)



#define IO_TCTX_REFS_CACHE_NR	(1U << 10)



struct io_uring {
@@ -2626,15 +2629,20 @@ static void io_free_batch_list(struct io_ring_ctx *ctx, 
		struct io_kiocb *req = container_of(node, struct io_kiocb,

						    comp_list);



		if (unlikely(req->flags & REQ_F_REFCOUNT)) {

		if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {

			if (req->flags & REQ_F_REFCOUNT) {

				node = req->comp_list.next;

				if (!req_ref_put_and_test(req))

					continue;

			}

			io_queue_next(req);

			if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))

				io_clean_op(req);

		}

		if (!(req->flags & REQ_F_FIXED_FILE))

			io_put_file(req->file);



		io_req_put_rsrc_locked(req, ctx);

		io_queue_next(req);

		io_dismantle_req(req);



		if (req->task != task) {

			if (task)