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authorPavel Begunkov <asml.silence@gmail.com>2021-10-04 20:02:46 +0100
committerJens Axboe <axboe@kernel.dk>2021-10-19 05:49:54 -0600
commit7e3709d57651feab9c77d7a5a8024041f73f69f7 (patch)
tree750ac9c551a1791792c7a15b104c0684aa393c04
parent6224590d242fc8c6b26941328e02a40b4384949b (diff)
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: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/9d9dde31f8f62279a5f48c575bbc27b8290edc0c.1633373302.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/io_uring.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 5b3b4f8f9659..ab07a0813f20 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -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;
};