From: Pavel Begunkov <[email protected]>
To: [email protected]
Cc: Jens Axboe <[email protected]>, [email protected]
Subject: [RFC v2 05/13] io_uring: parse check_cq out of wq waiting
Date: Tue, 3 Jan 2023 03:03:56 +0000 [thread overview]
Message-ID: <e28cb002457c26c6159de4d80e7c437fe13711b5.1672713341.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
We already avoid flushing overflows in io_cqring_wait_schedule() but
only return an error for the outer loop to handle it. Minimise it even
further by moving all ->check_cq parsing there.
Signed-off-by: Pavel Begunkov <[email protected]>
---
io_uring/io_uring.c | 32 ++++++++++++++++++--------------
1 file changed, 18 insertions(+), 14 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index ff457e525e7c..e3c5de299baa 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2468,21 +2468,13 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
ktime_t timeout)
{
int ret;
- unsigned long check_cq;
+ if (unlikely(READ_ONCE(ctx->check_cq)))
+ return 1;
/* make sure we run task_work before checking for signals */
ret = io_run_task_work_sig(ctx);
if (ret || io_should_wake(iowq))
return ret;
-
- check_cq = READ_ONCE(ctx->check_cq);
- if (unlikely(check_cq)) {
- /* let the caller flush overflows, retry */
- if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
- return 1;
- if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))
- return -EBADR;
- }
if (!schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS))
return -ETIME;
@@ -2548,13 +2540,25 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
trace_io_uring_cqring_wait(ctx, min_events);
do {
- if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {
- finish_wait(&ctx->cq_wait, &iowq.wq);
- io_cqring_do_overflow_flush(ctx);
- }
+ unsigned long check_cq;
+
prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
TASK_INTERRUPTIBLE);
ret = io_cqring_wait_schedule(ctx, &iowq, timeout);
+
+ check_cq = READ_ONCE(ctx->check_cq);
+ if (unlikely(check_cq)) {
+ /* let the caller flush overflows, retry */
+ if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)) {
+ finish_wait(&ctx->cq_wait, &iowq.wq);
+ io_cqring_do_overflow_flush(ctx);
+ }
+ if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) {
+ ret = -EBADR;
+ break;
+ }
+ }
+
if (__io_cqring_events_user(ctx) >= min_events)
break;
cond_resched();
--
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 ` Pavel Begunkov [this message]
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 ` [RFC v2 13/13] io_uring: add io_req_local_work_add wake fast path Pavel Begunkov
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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