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Subject: Re: [PATCH] io_uring: wakeup threads waiting for EPOLLOUT events
To:     Stefano Garzarella <sgarzare@redhat.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>, io-uring@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
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From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <2d3d4932-8894-6969-4006-25141ca1286e@kernel.dk>
Date:   Thu, 23 Jan 2020 12:13:57 -0700
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On 1/16/20 10:03 AM, Stefano Garzarella wrote:
> On Thu, Jan 16, 2020 at 09:30:12AM -0700, Jens Axboe wrote:
>> On 1/16/20 9:26 AM, Stefano Garzarella wrote:
>>>> Since the use case is mostly single submitter, unless you're doing
>>>> something funky or unusual, you're not going to be needing POLLOUT ever.
>>>
>>> The case that I had in mind was with kernel side polling enabled and
>>> a single submitter that can use epoll() to wait free slots in the SQ
>>> ring. (I don't have a test, maybe I can write one...)
>>
>> Right, I think that's the only use case where it makes sense, because
>> you have someone else draining the sq side for you. A test case would
>> indeed be nice, liburing has a good arsenal of test cases and this would
>> be a good addition!
> 
> Sure, I'll send a test to liburing for this case!

Gentle ping on the test case :-)

-- 
Jens Axboe