All of lore.kernel.org
 help / color / mirror / Atom feed
From: Minwoo Im <minwoo.im.dev@gmail.com>
To: Keith Busch <kbusch@kernel.org>
Cc: Jens Axboe <axboe@fb.com>, Chao Leng <lengchao@huawei.com>,
	Christoph Hellwig <hch@lst.de>,
	linux-nvme@lists.infradead.org, Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH V3 3/3] nvme: retry commands based on ACRE flag
Date: Wed, 20 Jan 2021 09:52:36 +0900	[thread overview]
Message-ID: <20210120005236.GD4205@localhost.localdomain> (raw)
In-Reply-To: <20210119180535.GA1520627@dhcp-10-100-145-180.wdc.com>

On 21-01-20 03:28:38, Keith Busch wrote:
> On Mon, Jan 18, 2021 at 06:40:51PM +0100, Christoph Hellwig wrote:
> > On Sat, Jan 16, 2021 at 03:26:02AM +0900, Minwoo Im wrote:
> > > > I am not sure we should ignore the FAILFAST for non-path errors. If we
> > > > need retryable admin commands, we should let the driver provide a way
> > > > for callers to dispatch requests without that flag.
> > > 
> > > Understood.  I thought the opposite way about FAILFAST in case with
> > > acre, if device is enabled with acre, all commands would be retried
> > > regardless to FAILFAST...  Thanks for pointing that out!
> > > 
> > > How do you think which one is right choice to go with if a user-space
> > > application(e.g., nvme-cli) wants a command to be retired in case of
> > > ACRE && Error && !DNR:
> > > 
> > >   - User-space application should figure out !DNR and retry the command.
> > >     (Maybe we are not able to easily figure out exact status code from
> > >     the user-space application by the return value).
> > > 
> > >   - Driver should retry the command right before putting result up to
> > >     the user-space even it's a FAILFAST request.
> > > 
> > > Thanks,
> > 
> > We could come up with a version of the ioctls that use the normal
> > retry mechanisms.  nvme_passthru_cmd64 has two reserved fields we
> > could use for UAPI flags like this.
> 
> Yeah, I'm totally okay with adding driver control flags for this sort of
> behavior.
> 
> For the moment, the ioctl interface has always been 1:1 for commands
> submitted to completions received, so all user space applications using
> this should have been prepared to receive unfiltered status back and
> handle retries on their own.

Thanks Keith for your feedback!

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

      reply	other threads:[~2021-01-20  0:52 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-14 13:31 [PATCH V3 0/3] nvme: fixes for command retry Minwoo Im
2021-01-14 13:31 ` [PATCH V3 1/3] nvme: check all retry delay times in Identify Controller Minwoo Im
2021-01-19  3:43   ` Minwoo Im
2021-01-14 13:31 ` [PATCH V3 2/3] nvme: introduce acre flag in nvme_ctrl Minwoo Im
2021-01-15  2:16   ` Chao Leng
2021-01-14 13:31 ` [PATCH V3 3/3] nvme: retry commands based on ACRE flag Minwoo Im
2021-01-15  2:17   ` Chao Leng
2021-01-15 17:04   ` Keith Busch
2021-01-15 18:26     ` Minwoo Im
2021-01-18 17:40       ` Christoph Hellwig
2021-01-19  3:30         ` Minwoo Im
2021-01-19 18:28         ` Keith Busch
2021-01-20  0:52           ` Minwoo Im [this message]

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=20210120005236.GD4205@localhost.localdomain \
    --to=minwoo.im.dev@gmail.com \
    --cc=axboe@fb.com \
    --cc=hch@lst.de \
    --cc=kbusch@kernel.org \
    --cc=lengchao@huawei.com \
    --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 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.