public inbox for linux-nvme@lists.infradead.org
 help / color / mirror / Atom feed
From: Clay Mayers <Clay.Mayers@kioxia.com>
To: "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Cc: Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
	Christoph Hellwig <hch@lst.de>,
	Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
	Sagi Grimberg <sagi@grimberg.me>
Subject: RE: [PATCH V2 0/2] nvme: Support for fused NVME_IOCTL_SUBMIT_IO
Date: Tue, 9 Feb 2021 00:53:17 +0000	[thread overview]
Message-ID: <b2a0593cd1fc4f239bbd44f3f43d4bcd@kioxia.com> (raw)
In-Reply-To: BYAPR04MB49652EA8F4CF06D41C708E2386BC9@BYAPR04MB4965.namprd04.prod.outlook.com

> From: Clay Mayers
> Sent: Tuesday, January 26, 2021 1:14 PM
> To: linux-nvme@lists.infradead.org
> Cc: Keith Busch <kbusch@kernel.org>; Jens Axboe <axboe@fb.com>;
> 'Chaitanya Kulkarni' <Chaitanya.Kulkarni@wdc.com>;
> Christoph Hellwig <hch@lst.de>; Sagi Grimberg <sagi@grimberg.me>
> Subject: RE: [PATCH V2 0/2] nvme: Support for fused
> NVME_IOCTL_SUBMIT_IO
>
Is there any other feedback on V2?

My main concern I have about my implementation is how fused requests
are tunneled through the mq request layer.  The 1st request is marked as
started but it won't be in the device until the 2nd command is queued.  As
Keith pointed out, a device reset can split the two so care must be taken to
correctly handle this case.  Despite this, I thought this was a better approach
than modifying mq requests to be fused.  Especially given Christoph's 
concern of cost vs value.  This is the lightest touch I could come up with.

Further consideration of this patch may need a more compelling use case.
I've worked on a proprietary storage systems that relied on fused NVMeOF
support so it seems compelling to me.  There's a comment in target/core.c
that there is "no support for fused commands yet" implying it's been
considered.  Is pci only support for fused too soon or too little?  What would
make it more compelling?






_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  parent reply	other threads:[~2021-02-09  0:53 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-05 22:49 [PATCH 0/2] nvme: Support for fused NVME_IOCTL_SUBMIT_IO klayph
2021-01-05 22:49 ` [PATCH 1/2] nvme: support fused nvme requests klayph
2021-01-05 23:52   ` Keith Busch
2021-01-06 14:55     ` Clay Mayers
2021-01-06  0:35   ` James Smart
2021-01-06 15:01     ` Clay Mayers
2021-01-06  7:59   ` Christoph Hellwig
2021-01-25 19:58   ` [PATCH V2 0/2] nvme: Support for fused NVME_IOCTL_SUBMIT_IO clay.mayers
2021-01-26  1:43     ` Chaitanya Kulkarni
2021-01-26 18:17       ` Clay Mayers
2021-01-26 19:00         ` Chaitanya Kulkarni
2021-01-26 21:14           ` Clay Mayers
2021-02-09  0:53           ` Clay Mayers [this message]
2021-02-09  3:12             ` Keith Busch
2021-02-09 15:24               ` Bart Van Assche
2021-02-09 15:38               ` Clay Mayers
2021-02-09  7:54             ` Christoph Hellwig
2021-02-09 15:53               ` Clay Mayers
2021-01-25 19:58   ` [PATCH V2 1/2] nvme: support fused pci nvme requests clay.mayers
2021-01-25 19:58   ` [PATCH V2 2/2] nvme: support fused NVME_IOCTL_SUBMIT_IO clay.mayers
2021-01-05 22:49 ` [PATCH " klayph
2021-01-05 23:04 ` [PATCH 0/2] nvme: Support for " James Smart

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=b2a0593cd1fc4f239bbd44f3f43d4bcd@kioxia.com \
    --to=clay.mayers@kioxia.com \
    --cc=Chaitanya.Kulkarni@wdc.com \
    --cc=axboe@fb.com \
    --cc=hch@lst.de \
    --cc=kbusch@kernel.org \
    --cc=linux-nvme@lists.infradead.org \
    --cc=sagi@grimberg.me \
    /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