task_work's are typically queued up from IRQ/softirq potentially by a
random CPU like in case of networking. Batch ctx fields bouncing as this
into a separate cache line.
We also move ->cq_timeouts there because waiters have to read and check
it. We can also conditionally hide ->cq_timeouts in the future from the
CQ wait path as a not really useful rudiment.
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
include/linux/io_uring_types.h | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 72e609752323..5de5dffe29df 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -270,15 +270,25 @@ struct io_ring_ctx {
unsigned cached_cq_tail;
unsigned cq_entries;
struct io_ev_fd __rcu *io_ev_fd;
- struct wait_queue_head cq_wait;
unsigned cq_extra;
} ____cacheline_aligned_in_smp;
+ /*
+ * task_work and async notification delivery cacheline. Expected to
+ * regularly bounce b/w CPUs.
+ */
+ struct {
+ struct llist_head work_llist;
+ unsigned long check_cq;
+ atomic_t cq_wait_nr;
+ atomic_t cq_timeouts;
+ struct wait_queue_head cq_wait;
+ } ____cacheline_aligned_in_smp;
+
struct {
spinlock_t completion_lock;
bool poll_multi_queue;
- atomic_t cq_wait_nr;
/*
* ->iopoll_list is protected by the ctx->uring_lock for
@@ -287,14 +297,11 @@ struct io_ring_ctx {
* manipulate the list, hence no extra locking is needed there.
*/
struct io_wq_work_list iopoll_list;
-
- struct llist_head work_llist;
} ____cacheline_aligned_in_smp;
/* timeouts */
struct {
spinlock_t timeout_lock;
- atomic_t cq_timeouts;
struct list_head timeout_list;
struct list_head ltimeout_list;
unsigned cq_last_tm_flush;
@@ -314,8 +321,6 @@ struct io_ring_ctx {
struct wait_queue_head sqo_sq_wait;
struct list_head sqd_list;
- unsigned long check_cq;
-
unsigned int file_alloc_start;
unsigned int file_alloc_end;
--
2.41.0
