[PATCH 10/12] io_uring: move uring_lock location

Pavel Begunkov
2021-06-14T22:38:20Z

->uring_lock is prevalently used for submission, even though it protects
many other things like iopoll, registeration, selected bufs, and more.
And it's placed together with ->cq_wait poked on completion and CQ
waiting sides. Move them apart, ->uring_lock goes to the submission
data, and cq_wait to completion related chunk. The last one requires
some reshuffling so everything needed by io_cqring_ev_posted*() is in
one cacheline.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e9bf26fbf65d..1b6cfc6b79c5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -356,6 +356,8 @@ struct io_ring_ctx {

/* submission data */
struct {
+ struct mutex uring_lock;
+
/*
* Ring buffer of indices into array of io_uring_sqe, which is
* mmapped by the application using the IORING_OFF_SQES offset.
@@ -392,11 +394,6 @@ struct io_ring_ctx {
unsigned sq_thread_idle;
} ____cacheline_aligned_in_smp;

- struct {
- struct mutex uring_lock;
- wait_queue_head_t cq_wait;
- } ____cacheline_aligned_in_smp;
-
/* IRQ completion list, under ->completion_lock */
struct list_head locked_free_list;
unsigned int locked_free_nr;
@@ -412,12 +409,13 @@ struct io_ring_ctx {
struct {
unsigned cached_cq_tail;
unsigned cq_entries;
- atomic_t cq_timeouts;
- unsigned cq_last_tm_flush;
- unsigned cq_extra;
+ struct eventfd_ctx *cq_ev_fd;
struct wait_queue_head poll_wait;
+ struct wait_queue_head cq_wait;
+ unsigned cq_extra;
+ atomic_t cq_timeouts;
struct fasync_struct *cq_fasync;
- struct eventfd_ctx *cq_ev_fd;
+ unsigned cq_last_tm_flush;
} ____cacheline_aligned_in_smp;

struct {
--
2.31.1