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From: Jens Axboe <>
To: Stefan Metzmacher <>,
	Pavel Begunkov <>,
Cc: "David S . Miller" <>,
	Jakub Kicinski <>,,,
	Josh Triplett <>
Subject: Re: [RFC 0/4] open/accept directly into io_uring fixed file table
Date: Wed, 7 Jul 2021 09:01:47 -0600	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 7/7/21 7:59 AM, Stefan Metzmacher wrote:
> Am 07.07.21 um 15:07 schrieb Jens Axboe:
>> On 7/7/21 5:39 AM, Pavel Begunkov wrote:
>>> Implement an old idea allowing open/accept io_uring requests to register
>>> a newly created file as a io_uring's fixed file instead of placing it
>>> into a task's file table. The switching is encoded in io_uring's SQEs
>>> by setting sqe->buf_index/file_index, so restricted to 2^16-1. Don't
>>> think we need more, but may be a good idea to scrap u32 somewhere
>>> instead.
>>> From the net side only needs a function doing __sys_accept4_file()
>>> but not installing fd, see 2/4.
>>> Only RFC for now, the new functionality is tested only for open yet.
>>> I hope we can remember the author of the idea to add attribution.
>> Pretty sure the original suggester of this as Josh, CC'ed.
> I also requested it for open :-)

Indeed! I honestly forget the details, as some of it is implementation
detail. I think Josh was the first to suggest a private fd table could
be used, but that's mostly implementation detail as the point was to be
able to know which fd would be assigned.

But I think we're all in agreement here, it's a nifty feature :-)

Jens Axboe

  reply	other threads:[~2021-07-07 15:02 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-07 11:39 Pavel Begunkov
2021-07-07 11:39 ` [PATCH 1/4] io_uring: allow open directly into fixed fd table Pavel Begunkov
2021-07-07 11:39 ` [PATCH 2/4] net: add an accept helper not installing fd Pavel Begunkov
2021-07-07 11:39 ` [PATCH 3/4] io_uring: hand code io_accept()' fd installing Pavel Begunkov
2021-07-07 11:39 ` [PATCH 4/4] io_uring: accept directly into fixed file table Pavel Begunkov
2021-07-07 13:07 ` [RFC 0/4] open/accept directly into io_uring " Jens Axboe
2021-07-07 13:59   ` Stefan Metzmacher
2021-07-07 15:01     ` Jens Axboe [this message]
2021-07-07 15:04   ` Josh Triplett
2021-08-13 16:30     ` Pavel Begunkov
2021-07-21  7:11 ` Hao Xu

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