Hi,

Can you add the below to 6.1-stable? Thanks!

commit 3181e22fb79910c7071e84a43af93ac89e8a7106 Author: Pavel Begunkov asml.silence@gmail.com Date: Mon Jan 9 14:46:10 2023 +0000

io_uring: wake up optimisations

Commit 3181e22fb79910c7071e84a43af93ac89e8a7106 upstream.

Flush completions is done either from the submit syscall or by the task_work, both are in the context of the submitter task, and when it goes for a single threaded rings like implied by ->task_complete, there won't be any waiters on ->cq_wait but the master task. That means that there can be no tasks sleeping on cq_wait while we run __io_submit_flush_completions() and so waking up can be skipped.

Signed-off-by: Pavel Begunkov asml.silence@gmail.com Link: https://lore.kernel.org/r/60ad9768ec74435a0ddaa6eec0ffa7729474f69f.167327424... Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 4f0ae938b146..0b1361663267 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -582,6 +582,16 @@ static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx) io_cqring_ev_posted(ctx); }

+static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) + __releases(ctx->completion_lock) +{ + io_commit_cqring(ctx); + spin_unlock(&ctx->completion_lock); + io_commit_cqring_flush(ctx); + if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) + __io_cqring_wake(ctx); +} + void io_cq_unlock_post(struct io_ring_ctx *ctx) { __io_cq_unlock_post(ctx); @@ -1339,7 +1349,7 @@ static void __io_submit_flush_completions(struct io_ring_ctx *ctx) if (!(req->flags & REQ_F_CQE_SKIP)) __io_fill_cqe_req(ctx, req); } - __io_cq_unlock_post(ctx); + __io_cq_unlock_post_flush(ctx);

io_free_batch_list(ctx, state->compl_reqs.first); INIT_WQ_LIST(&state->compl_reqs);