Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O scheduler

From	"Austin S. Hemmelgarn" <ahferroin7@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O scheduler
Date	2016-03-11 14:50 +0100
Message-ID	<rbvC1-70o-3@gated-at.bofh.it> (permalink)
References	(6 earlier) <r7XwS-4vn-19@gated-at.bofh.it> <r91I5-1ID-11@gated-at.bofh.it> <r91RL-1Nv-3@gated-at.bofh.it> <r92uu-2hO-7@gated-at.bofh.it> <rbtgS-5hR-17@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 2016-03-11 06:16, Christoph Hellwig wrote:
> On Fri, Mar 04, 2016 at 01:10:31PM -0500, Austin S. Hemmelgarn wrote:
>> 1. This all started long before blk-mq hit mainline.
>
> Whoe cares? :)
It wasn't intended as an argument for this continuing to be developed 
outside of blk-mq, but as an explanation of why the code exists as it 
does right now.
>> 2. There's still a decent amount of block drivers that don't support blk-mq.
>> Last time I looked (around the time 4.4 came out), I saw the following that
>> either obviously don't support it, or are ambiguous as to whether they
>> support it or not.  Here's a list of just the ones I know are being used on
>> existing systems running relatively recent kernel versions, not including
>
> There is no ambiguouity.  You clearly named a few ones that aren't
> converted, but also a lot of make_request_fn based drivers which don't
> support any I/O scheduler.
For someone reading the code there might not be any ambiguity, but from 
the perspective of someone who isn't reading the code (or even someone 
who has limited background in kernel programming), it very much is 
ambiguous, especially what does and doesn't support I/O scheduling in 
general.
> But that whole point is that anything actively developed should move
> over.
Agreed.

Thread

Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O scheduler Linus Walleij <linus.walleij@linaro.org> - 2016-03-04 18:30 +0100
  Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O  scheduler Christoph Hellwig <hch@infradead.org> - 2016-03-04 18:40 +0100
    Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O  scheduler "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2016-03-04 19:20 +0100
      Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O  scheduler Christoph Hellwig <hch@infradead.org> - 2016-03-11 12:20 +0100
        Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O  scheduler "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2016-03-11 14:50 +0100
    Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O scheduler Linus Walleij <linus.walleij@linaro.org> - 2016-03-05 13:20 +0100
      Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O  scheduler Christoph Hellwig <hch@infradead.org> - 2016-03-11 12:20 +0100
        Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O  scheduler Nikolay Borisov <kernel@kyup.com> - 2016-03-11 12:30 +0100
          Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O  scheduler Christoph Hellwig <hch@infradead.org> - 2016-03-11 12:50 +0100
        Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O scheduler Linus Walleij <linus.walleij@linaro.org> - 2016-03-11 16:00 +0100
    Re: [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O scheduler Paolo Valente <paolo.valente@linaro.org> - 2016-03-09 08:00 +0100

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