Commit 7e3709d5 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: optimise kiocb layout 



We want ->comp_list in the second cacheline, which is hotter comparing
to the 3rd. Swap the field with ->link, which is not as hot and
controlled by flags and so not accessed unless there is a link.

By the way add a couple of comments for io_kiocb fields.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9d9dde31f8f62279a5f48c575bbc27b8290edc0c.1633373302.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 6224590d

fs/io_uring.c

+5 −2
Original line number Diff line number Diff line
@@ -863,19 +863,22 @@ struct io_kiocb { 
	struct task_struct		*task;

	u64				user_data;



	struct io_kiocb			*link;

	struct percpu_ref		*fixed_rsrc_refs;



	/* used with ctx->iopoll_list with reads/writes */

	/* used by request caches, completion batching and iopoll */

	struct io_wq_work_node		comp_list;

	struct io_kiocb			*link;

	struct io_task_work		io_task_work;

	/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */

	struct hlist_node		hash_node;

	/* internal polling, see IORING_FEAT_FAST_POLL */

	struct async_poll		*apoll;

	/* store used ubuf, so we can prevent reloading */

	struct io_mapped_ubuf		*imu;

	struct io_wq_work		work;

	/* custom credentials, valid IFF REQ_F_CREDS is set */

	const struct cred		*creds;

	/* stores selected buf, valid IFF REQ_F_BUFFER_SELECTED is set */

	struct io_buffer		*kbuf;

};