io_uring: keep SQ pointers in a single cacheline

sq_array and sq_sqes are always used together, however they are in
different cachelines, where the borderline is right before
cq_overflow_list is rather rarely touched. Move the fields together so
it loads only one cacheline.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3ef2411a94874da06492506a8897eff679244f49.1623709150.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -364,6 +364,7 @@ struct io_ring_ctx {
 		 * array.
 		 */
 		u32			*sq_array;
+		struct io_uring_sqe	*sq_sqes;
 		unsigned		cached_sq_head;
 		unsigned		sq_entries;
 		unsigned		sq_thread_idle;
@@ -373,8 +374,6 @@ struct io_ring_ctx {
 		struct list_head	defer_list;
 		struct list_head	timeout_list;
 		struct list_head	cq_overflow_list;
-
-		struct io_uring_sqe	*sq_sqes;
 	} ____cacheline_aligned_in_smp;
 
 	struct {