> On May 19, 2021, at 7:13 AM, Pavel Begunkov <asml.silence@xxxxxxxxx> wrote:
>
> There is a bunch of scattered around ctx fields that are almost never
> used, e.g. only on ring exit, plunge them to the end, better locality,
> better aesthetically.
>
> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> ---
> fs/io_uring.c | 36 +++++++++++++++++-------------------
> 1 file changed, 17 insertions(+), 19 deletions(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 9ac5e278a91e..7e3410ce100a 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -367,9 +367,6 @@ struct io_ring_ctx {
> unsigned cached_cq_overflow;
> unsigned long sq_check_overflow;
>
> - /* hashed buffered write serialization */
> - struct io_wq_hash *hash_map;
> -
> struct list_head defer_list;
> struct list_head timeout_list;
> struct list_head cq_overflow_list;
> @@ -386,9 +383,6 @@ struct io_ring_ctx {
>
> struct io_rings *rings;
>
> - /* Only used for accounting purposes */
> - struct mm_struct *mm_account;
> -
> const struct cred *sq_creds; /* cred used for __io_sq_thread() */
> struct io_sq_data *sq_data; /* if using sq thread polling */
>
> @@ -409,14 +403,6 @@ struct io_ring_ctx {
> unsigned nr_user_bufs;
> struct io_mapped_ubuf **user_bufs;
>
> - struct user_struct *user;
> -
> - struct completion ref_comp;
> -
> -#if defined(CONFIG_UNIX)
> - struct socket *ring_sock;
> -#endif
> -
> struct xarray io_buffers;
>
> struct xarray personalities;
> @@ -460,12 +446,24 @@ struct io_ring_ctx {
>
> struct io_restriction restrictions;
>
> - /* exit task_work */
> - struct callback_head *exit_task_work;
> -
> /* Keep this last, we don't need it for the fast path */
> - struct work_struct exit_work;
> - struct list_head tctx_list;
> + struct {
Why do we need an anonymous struct here? For cache line alignment?
Do we need ____cacheline_aligned_in_smp?
> + #if defined(CONFIG_UNIX)
> + struct socket *ring_sock;
> + #endif
> + /* hashed buffered write serialization */
> + struct io_wq_hash *hash_map;
> +
> + /* Only used for accounting purposes */
> + struct user_struct *user;
> + struct mm_struct *mm_account;
> +
> + /* ctx exit and cancelation */
> + struct callback_head *exit_task_work;
> + struct work_struct exit_work;
> + struct list_head tctx_list;
> + struct completion ref_comp;
> + };
> };
>
> struct io_uring_task {
> --
> 2.31.1
>
