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From: Jeff Moyer <jmoyer@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>, io-uring@vger.kernel.org
Subject: Re: [RFC 2/2] io_uring: mark REQ_NOWAIT for a non-mq queue as unspported
Date: Fri, 29 May 2020 11:02:29 -0400	[thread overview]
Message-ID: <x49h7vyzsvu.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <6ca210e3-eba6-0621-3ebc-d3545f5ad7e9@kernel.dk> (Jens Axboe's message of "Thu, 28 May 2020 17:03:39 -0600")

Jens Axboe <axboe@kernel.dk> writes:

> On 5/28/20 4:12 PM, Jeff Moyer wrote:
>> Jens Axboe <axboe@kernel.dk> writes:
>> 
>>>> poll won't work over dm, so that looks correct. What happens if you edit
>>>> it and disable poll? Would be curious to see both buffered = 0 and
>>>> buffered = 1 runs with that.
>>>>
>>>> I'll try this here too.
>>>
>>> I checked, and with the offending commit reverted, it behaves exactly
>>> like it should - io_uring doesn't hit endless retries, and we still
>>> return -EAGAIN to userspace for preadv2(..., RFW_NOWAIT) if not supported.
>>> I've queued up the revert.
>> 
>> With that revert, I now see an issue with an xfs file system on top of
>> an nvme device when running the liburing test suite:
>> 
>> Running test 500f9fbadef8-test
>> Test 500f9fbadef8-test failed with ret 130
>> 
>> That means the test harness timed out, so we never received a
>> completion.
>
> I can't reproduce this. Can you try again, and enable io_uring tracing?
>
> # echo 1 > /sys/kernel/debug/tracing/events/io_uring/enable
>
> run test
>
> send the 'trace' file, or take a look and see what is going on.

I took a look, and it appeared as though the issue was not in the
kernel.  My liburing was not uptodate, and after grabbing the latest,
the test runs to completion.

Thanks!
Jeff


  reply	other threads:[~2020-05-29 15:02 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-19 21:52 [RFC 0/2] io_uring: don't use kiocb.private to store buf_index Bijan Mottahedeh
2020-05-19 21:52 ` [RFC 1/2] " Bijan Mottahedeh
2020-05-19 22:07   ` Jens Axboe
2020-05-19 22:20     ` Jens Axboe
2020-05-19 22:48       ` Bijan Mottahedeh
2020-05-19 21:52 ` [RFC 2/2] io_uring: mark REQ_NOWAIT for a non-mq queue as unspported Bijan Mottahedeh
2020-05-28 18:35   ` Jeff Moyer
2020-05-28 19:01     ` Jens Axboe
2020-05-28 19:22       ` Jens Axboe
2020-05-28 19:31         ` Jeff Moyer
2020-05-28 22:12         ` Jeff Moyer
2020-05-28 23:03           ` Jens Axboe
2020-05-29 15:02             ` Jeff Moyer [this message]
2020-05-29 16:20               ` Jens Axboe

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