From: Pavel Begunkov <[email protected]>
To: [email protected]
Cc: Jens Axboe <[email protected]>, [email protected]
Subject: [RFC v2 13/13] io_uring: add io_req_local_work_add wake fast path
Date: Tue, 3 Jan 2023 03:04:04 +0000 [thread overview]
Message-ID: <f7c52527313e6f0d8dff2bb36ecad2380f5c5c9c.1672713341.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
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 <[email protected]>
---
include/linux/io_uring_types.h | 1 +
io_uring/io_uring.c | 6 +++++-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 1452ff745e5c..332a29cfe076 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -285,6 +285,7 @@ struct io_ring_ctx {
unsigned cached_cq_tail;
unsigned cq_entries;
+ bool cq_waiting;
struct io_ev_fd __rcu *io_ev_fd;
struct wait_queue_head cq_wait;
struct wait_queue_head poll_wq;
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 943032d2fd21..e436fe73becf 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1275,7 +1275,8 @@ static void io_req_local_work_add(struct io_kiocb *req)
io_eventfd_signal(ctx);
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
- wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE);
+ if (READ_ONCE(ctx->cq_waiting))
+ wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE);
} else {
__io_cqring_wake(ctx);
}
@@ -2565,6 +2566,7 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
set_current_state(TASK_INTERRUPTIBLE);
+ smp_store_mb(ctx->cq_waiting, 1);
} else {
prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
TASK_INTERRUPTIBLE);
@@ -2572,6 +2574,8 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
ret = io_cqring_wait_schedule(ctx, &iowq, timeout);
__set_current_state(TASK_RUNNING);
+ WRITE_ONCE(ctx->cq_waiting, 0);
+
if (ret < 0)
break;
/*
--
2.38.1
next prev parent reply other threads:[~2023-01-03 3:05 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-03 3:03 [RFC v2 00/13] CQ waiting and wake up optimisations Pavel Begunkov
2023-01-03 3:03 ` [RFC v2 01/13] io_uring: rearrange defer list checks Pavel Begunkov
2023-01-03 3:03 ` [RFC v2 02/13] io_uring: don't iterate cq wait fast path Pavel Begunkov
2023-01-03 3:03 ` [RFC v2 03/13] io_uring: kill io_run_task_work_ctx Pavel Begunkov
2023-01-03 3:03 ` [RFC v2 04/13] io_uring: move defer tw task checks Pavel Begunkov
2023-01-03 3:03 ` [RFC v2 05/13] io_uring: parse check_cq out of wq waiting Pavel Begunkov
2023-01-03 3:03 ` [RFC v2 06/13] io_uring: mimimise io_cqring_wait_schedule Pavel Begunkov
2023-01-03 3:03 ` [RFC v2 07/13] io_uring: simplify io_has_work Pavel Begunkov
2023-01-03 3:03 ` [RFC v2 08/13] io_uring: set TASK_RUNNING right after schedule Pavel Begunkov
2023-01-03 3:04 ` [RFC v2 09/13] io_uring: separate wq for ring polling Pavel Begunkov
2023-01-04 18:08 ` Jens Axboe
2023-01-04 20:28 ` Pavel Begunkov
2023-01-04 20:34 ` Jens Axboe
2023-01-04 20:45 ` Pavel Begunkov
2023-01-04 20:53 ` Jens Axboe
2023-01-04 20:52 ` Jens Axboe
2023-01-03 3:04 ` [RFC v2 10/13] io_uring: add lazy poll_wq activation Pavel Begunkov
2023-01-03 3:04 ` [RFC v2 11/13] io_uring: wake up optimisations Pavel Begunkov
2023-01-03 3:04 ` [RFC v2 12/13] io_uring: waitqueue-less cq waiting Pavel Begunkov
2023-01-03 3:04 ` Pavel Begunkov [this message]
2023-01-04 18:05 ` (subset) [RFC v2 00/13] CQ waiting and wake up optimisations Jens Axboe
2023-01-04 20:25 ` Pavel Begunkov
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