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.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 3692bbc..8c501ee 100644 (file)
--- a/fs/io_uring.c
+++ b/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 {