public inbox for [email protected]
 help / color / mirror / Atom feed
From: Kanchan Joshi <[email protected]>
To: Ming Lei <[email protected]>
Cc: Kanchan Joshi <[email protected]>, Jens Axboe <[email protected]>,
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected]
Subject: Re: [LSF/MM/BPF ATTEND][LSF/MM/BPF Topic] Non-block IO
Date: Wed, 12 Apr 2023 18:56:15 +0530	[thread overview]
Message-ID: <20230412132615.GA5049@green5> (raw)
In-Reply-To: <[email protected]>

[-- Attachment #1: Type: text/plain, Size: 1846 bytes --]

On Wed, Apr 12, 2023 at 10:33:40AM +0800, Ming Lei wrote:
>On Wed, Apr 12, 2023 at 04:18:16AM +0530, Kanchan Joshi wrote:
>> > > 4. Direct NVMe queues - will there be interest in having io_uring
>> > > managed NVMe queues?  Sort of a new ring, for which I/O is destaged from
>> > > io_uring SQE to NVMe SQE without having to go through intermediate
>> > > constructs (i.e., bio/request). Hopefully,that can further amp up the
>> > > efficiency of IO.
>> >
>> > This is interesting, and I've pondered something like that before too. I
>> > think it's worth investigating and hacking up a prototype. I recently
>> > had one user of IOPOLL assume that setting up a ring with IOPOLL would
>> > automatically create a polled queue on the driver side and that is what
>> > would be used for IO. And while that's not how it currently works, it
>> > definitely does make sense and we could make some things faster like
>> > that. It would also potentially easier enable cancelation referenced in
>> > #1 above, if it's restricted to the queue(s) that the ring "owns".
>>
>> So I am looking at prototyping it, exclusively for the polled-io case.
>> And for that, is there already a way to ensure that there are no
>> concurrent submissions to this ring (set with IORING_SETUP_IOPOLL
>> flag)?
>> That will be the case generally (and submissions happen under
>> uring_lock mutex), but submission may still get punted to io-wq
>> worker(s) which do not take that mutex.
>> So the original task and worker may get into doing concurrent submissions.
>
>It seems one defect for uring command support, since io_ring_ctx and
>io_ring_submit_lock() can't be exported for driver.

Sorry, did not follow the defect part.
io-wq not acquring uring_lock in case of uring-cmd - is a defect? 
The same happens for direct block-io too.
Or do you mean anything else here?

[-- Attachment #2: Type: text/plain, Size: 0 bytes --]



  reply	other threads:[~2023-04-12 13:36 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20230210180226epcas5p1bd2e1150de067f8af61de2bbf571594d@epcas5p1.samsung.com>
2023-02-10 18:00 ` [LSF/MM/BPF ATTEND][LSF/MM/BPF Topic] Non-block IO Kanchan Joshi
2023-02-10 18:18   ` Bart Van Assche
2023-02-10 19:34     ` Kanchan Joshi
2023-02-13 20:24       ` Bart Van Assche
2023-02-10 19:47     ` Jens Axboe
2023-02-14 10:33     ` John Garry
2023-02-10 19:53   ` Jens Axboe
2023-02-13 11:54     ` Sagi Grimberg
2023-04-11 22:48     ` Kanchan Joshi
2023-04-11 22:53       ` Jens Axboe
2023-04-11 23:28         ` Kanchan Joshi
2023-04-12  2:12           ` Jens Axboe
2023-04-12  2:33       ` Ming Lei
2023-04-12 13:26         ` Kanchan Joshi [this message]
2023-04-12 13:47           ` Ming Lei
2023-02-10 20:07   ` Clay Mayers
2023-02-11  3:33   ` Ming Lei
2023-02-11 12:06   ` Hannes Reinecke
2023-02-28 16:05   ` John Meneghini

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20230412132615.GA5049@green5 \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox