All of lore.kernel.org
 help / color / mirror / Atom feed
From: Bart Van Assche <bvanassche@acm.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org,
	Damien Le Moal <damien.lemoal@opensource.wdc.com>
Subject: Re: [PATCH v2 6/6] block/null_blk: Add support for pipelining zoned writes
Date: Fri, 24 Jun 2022 09:45:54 -0700	[thread overview]
Message-ID: <31602226-611f-223e-ddd3-0c8ab780cb0b@acm.org> (raw)
In-Reply-To: <20220624060659.GA6494@lst.de>

On 6/23/22 23:06, Christoph Hellwig wrote:
> I don't think adding all the previous code just for null_blk is a good
> idea.  We need a real user of it first.

Hi Christoph,

Although these patches work fine in our tests with zoned UFS prototypes, 
these patches have been tested with a UFSHCI 3.0 controller. While the 
UFSHCI 4.0 standard supports multiple queues and while UFSHCI 4.0 
controllers process each queue in order, with UFSHCI 3.0 controllers 
submitting requests happens by writing into a 32-bit doorbell register, 
just like for AHCI controllers. So although our UFS tests pass it cannot 
be guaranteed for UFSHCI 3.0 controllers that requests are propagated to 
the UFS device in the same order these have been submitted to the 
controller.

I have not yet seen any UFSHCI 4.0 implementation. The upstream UFSHCI 
driver does not yet support it either.

Hence the choice to add support to the null_blk driver for setting the 
QUEUE_FLAG_PIPELINE_ZONED_WRITES flag.

Thanks,

Bart.

  reply	other threads:[~2022-06-24 16:46 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-23 23:25 [PATCH v2 0/6] Improve zoned storage write performance Bart Van Assche
2022-06-23 23:25 ` [PATCH v2 1/6] block: Document blk_queue_zone_is_seq() and blk_rq_zone_is_seq() Bart Van Assche
2022-06-24  0:10   ` Damien Le Moal
2022-06-23 23:25 ` [PATCH v2 2/6] block: Introduce the blk_rq_is_zoned_seq_write() function Bart Van Assche
2022-06-24  0:15   ` Damien Le Moal
2022-06-24  6:07   ` Christoph Hellwig
2022-06-24 16:35     ` Bart Van Assche
2022-06-23 23:26 ` [PATCH v2 3/6] block: Introduce a request queue flag for pipelining zoned writes Bart Van Assche
2022-06-24  0:19   ` Damien Le Moal
2022-06-24 16:29     ` Bart Van Assche
2022-06-23 23:26 ` [PATCH v2 4/6] block/mq-deadline: Only use zone locking if necessary Bart Van Assche
2022-06-24  0:24   ` Damien Le Moal
2022-06-23 23:26 ` [PATCH v2 5/6] block/null_blk: Refactor null_queue_rq() Bart Van Assche
2022-06-24  0:26   ` Damien Le Moal
2022-06-23 23:26 ` [PATCH v2 6/6] block/null_blk: Add support for pipelining zoned writes Bart Van Assche
2022-06-24  0:29   ` Damien Le Moal
2022-06-24  6:06   ` Christoph Hellwig
2022-06-24 16:45     ` Bart Van Assche [this message]
2022-06-25  9:25       ` Christoph Hellwig
2022-06-26  0:23         ` Bart Van Assche

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=31602226-611f-223e-ddd3-0c8ab780cb0b@acm.org \
    --to=bvanassche@acm.org \
    --cc=axboe@kernel.dk \
    --cc=damien.lemoal@opensource.wdc.com \
    --cc=hch@lst.de \
    --cc=linux-block@vger.kernel.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.