From d80c0f00d04766972c95e72b7535a842d6f4680d Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Mon, 9 Jan 2023 14:46:12 +0000 Subject: [PATCH] io_uring: add io_req_local_work_add wake fast path Don't wake the master task after queueing a deferred tw unless it's currently waiting in io_cqring_wait. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/717702d772825a6647e6c315b4690277ba84c3fc.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- include/linux/io_uring_types.h | 1 + io_uring/io_uring.c | 7 ++++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index 7b5e90520278..cc0cf0705b8f 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -295,6 +295,7 @@ struct io_ring_ctx { spinlock_t completion_lock; bool poll_multi_queue; + bool cq_waiting; /* * ->iopoll_list is protected by the ctx->uring_lock for diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index be26829f7d20..3f92028a7ee8 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1276,7 +1276,9 @@ static void io_req_local_work_add(struct io_kiocb *req) atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags); if (ctx->has_evfd) io_eventfd_signal(ctx); - wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE); + + if (READ_ONCE(ctx->cq_waiting)) + wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE); percpu_ref_put(&ctx->refs); } @@ -2576,6 +2578,7 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, unsigned long check_cq; if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) { + WRITE_ONCE(ctx->cq_waiting, 1); set_current_state(TASK_INTERRUPTIBLE); } else { prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq, @@ -2584,6 +2587,8 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, ret = io_cqring_wait_schedule(ctx, &iowq); __set_current_state(TASK_RUNNING); + WRITE_ONCE(ctx->cq_waiting, 0); + if (ret < 0) break; /*