From: Jens Axboe <axboe@kernel.dk>
To: Alexander Babayants <babayants.alexander@gmail.com>,
io-uring@vger.kernel.org
Subject: Re: Submitting IO events with IORING_FEAT_NODROP and overflown CQ ring
Date: Sun, 5 May 2024 12:11:13 -0600 [thread overview]
Message-ID: <15ea2df8-f2e3-4cc5-89e0-1abb2279a55b@kernel.dk> (raw)
In-Reply-To: <CAB92dJbb3aMD14sHwQGDQYofj3H5hH84QTXuzQZ44TZQp0j1Ew@mail.gmail.com>
On 5/3/24 5:21 PM, Alexander Babayants wrote:
> Hi!
>
> Per io_uring_setup(2):
>
>> IORING_FEAT_NODROP
> ...
>> If this overflow condition is entered,
>> attempting to submit more IO will fail with the -EBUSY
>> error value, if it can't flush the overflown events to the
>> CQ ring. If this happens, the application must reap events
>> from the CQ ring and attempt the submit again.
>
> But I'm not getting -EBUSY on a 6.2 kernel when submitting to the ring
> with a full CQ ring and an overflow flag set. I'm not an expert in
> uring code, but it seems the error was removed in commit
> 1b346e4aa8e79227391ffd6b7c6ee5acf0fa8bfc. Could you please check if
> I'm right and if that change was intentional?
This is correct and intentional. The man page should get updated with a
note on the current behavior.
--
Jens Axboe
prev parent reply other threads:[~2024-05-05 18:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-03 23:21 Submitting IO events with IORING_FEAT_NODROP and overflown CQ ring Alexander Babayants
2024-05-05 18:11 ` Jens Axboe [this message]
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