From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>, Victor Stewart <v@nametag.social>
Cc: io-uring <io-uring@vger.kernel.org>
Subject: Re: bug with fastpoll accept and sqpoll + IOSQE_FIXED_FILE
Date: Tue, 2 Feb 2021 20:56:53 +0000 [thread overview]
Message-ID: <5c3d084f-88e4-3e86-3560-95d90bb9ffcd@gmail.com> (raw)
In-Reply-To: <725fa06a-da7e-9918-49b4-7489672ff0b4@kernel.dk>
On 02/02/2021 20:48, Jens Axboe wrote:
> On 2/2/21 1:34 PM, Pavel Begunkov wrote:
>> On 02/02/2021 17:41, Pavel Begunkov wrote:
>>> On 02/02/2021 17:24, Jens Axboe wrote:
>>>> On 2/2/21 10:10 AM, Victor Stewart wrote:
>>>>>> Can you send the updated test app?
>>>>>
>>>>> https://gist.github.com/victorstewart/98814b65ed702c33480487c05b40eb56
>>>>>
>>>>> same link i just updated the same gist
>>>>
>>>> And how are you running it?
>>>
>>> with SQPOLL with FIXED FLAG -> FAILURE: failed with error = ???
>>> -> io_uring_wait_cqe_timeout() strangely returns -1, (-EPERM??)
>>
>> Ok, _io_uring_get_cqe() is just screwed twice
>>
>> TL;DR
>> we enter into it with submit=0, do an iteration, which decrements it,
>> then a second iteration passes submit=-1, which is returned back by
>> the kernel as a result and propagated back from liburing...
>
> Yep, that's what I came up with too. We really just need a clear way
> of knowing when to break out, and when to keep going. Eg if we've
> done a loop and don't end up calling the system call, then there's
> no point in continuing.
We can bodge something up (and forget about it), and do much cleaner
for IORING_FEAT_EXT_ARG, because we don't have LIBURING_UDATA_TIMEOUT
reqs for it and so can remove peek and so on.
--
Pavel Begunkov
next prev parent reply other threads:[~2021-02-02 21:02 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 5:36 bug with fastpoll accept and sqpoll + IOSQE_FIXED_FILE Victor Stewart
2021-02-02 11:05 ` Pavel Begunkov
2021-02-02 11:23 ` Pavel Begunkov
2021-02-02 16:18 ` Victor Stewart
2021-02-02 16:30 ` Victor Stewart
2021-02-02 16:44 ` Jens Axboe
2021-02-02 17:10 ` Victor Stewart
2021-02-02 17:24 ` Jens Axboe
2021-02-02 17:41 ` Pavel Begunkov
2021-02-02 20:34 ` Pavel Begunkov
2021-02-02 20:48 ` Jens Axboe
2021-02-02 20:56 ` Pavel Begunkov [this message]
2021-02-03 11:49 ` Pavel Begunkov
2021-02-04 16:50 ` Jens Axboe
2021-02-05 12:46 ` Pavel Begunkov
2021-02-05 14:42 ` Jens Axboe
2021-02-05 14:49 ` Pavel Begunkov
2021-02-02 17:46 ` Jens Axboe
2021-02-02 17:50 ` Victor Stewart
2021-02-02 17:57 ` Jens Axboe
2021-02-02 17:46 ` Victor Stewart
2021-02-02 17:21 ` Pavel Begunkov
2021-02-02 17:30 ` Victor Stewart
2021-02-02 17:45 ` Victor Stewart
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