From: Parav Pandit <parav@mellanox.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Jiri Pirko <jiri@mellanox.com>,
"David S . Miller" <davem@davemloft.net>,
Kirti Wankhede <kwankhede@nvidia.com>,
Cornelia Huck <cohuck@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
cjia <cjia@nvidia.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: RE: [PATCH v2 0/2] Simplify mtty driver and mdev core
Date: Wed, 21 Aug 2019 06:23:17 +0000 [thread overview]
Message-ID: <AM0PR05MB4866437FAA63C447CACCD7E5D1AA0@AM0PR05MB4866.eurprd05.prod.outlook.com> (raw)
In-Reply-To: <20190820232622.164962d3@x1.home>
> -----Original Message-----
> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Wednesday, August 21, 2019 10:56 AM
> To: Parav Pandit <parav@mellanox.com>
> Cc: Jiri Pirko <jiri@mellanox.com>; David S . Miller <davem@davemloft.net>;
> Kirti Wankhede <kwankhede@nvidia.com>; Cornelia Huck
> <cohuck@redhat.com>; kvm@vger.kernel.org; linux-kernel@vger.kernel.org;
> cjia <cjia@nvidia.com>; netdev@vger.kernel.org
> Subject: Re: [PATCH v2 0/2] Simplify mtty driver and mdev core
>
> > > > > Just an example of the alias, not proposing how it's set. In
> > > > > fact, proposing that the user does not set it, mdev-core
> > > > > provides one
> > > automatically.
> > > > >
> > > > > > > Since there seems to be some prefix overhead, as I ask about
> > > > > > > above in how many characters we actually have to work with
> > > > > > > in IFNAMESZ, maybe we start with 8 characters (matching your
> > > > > > > "index" namespace) and expand as necessary for disambiguation.
> > > > > > > If we can eliminate overhead in IFNAMESZ, let's start with 12.
> > > > > > > Thanks,
> > > > > > >
> > > > > > If user is going to choose the alias, why does it have to be limited to
> sha1?
> > > > > > Or you just told it as an example?
> > > > > >
> > > > > > It can be an alpha-numeric string.
> > > > >
> > > > > No, I'm proposing a different solution where mdev-core creates
> > > > > an alias based on an abbreviated sha1. The user does not provide the
> alias.
> > > > >
> > > > > > Instead of mdev imposing number of characters on the alias, it
> > > > > > should be best
> > > > > left to the user.
> > > > > > Because in future if netdev improves on the naming scheme,
> > > > > > mdev will be
> > > > > limiting it, which is not right.
> > > > > > So not restricting alias size seems right to me.
> > > > > > User configuring mdev for networking devices in a given kernel
> > > > > > knows what
> > > > > user is doing.
> > > > > > So user can choose alias name size as it finds suitable.
> > > > >
> > > > > That's not what I'm proposing, please read again. Thanks,
> > > >
> > > > I understood your point. But mdev doesn't know how user is going
> > > > to use
> > > udev/systemd to name the netdev.
> > > > So even if mdev chose to pick 12 characters, it could result in collision.
> > > > Hence the proposal to provide the alias by the user, as user know
> > > > the best
> > > policy for its use case in the environment its using.
> > > > So 12 character sha1 method will still work by user.
> > >
> > > Haven't you already provided examples where certain drivers or
> > > subsystems have unique netdev prefixes? If mdev provides a unique
> > > alias within the subsystem, couldn't we simply define a netdev
> > > prefix for the mdev subsystem and avoid all other collisions? I'm
> > > not in favor of the user providing both a uuid and an
> > > alias/instance. Thanks,
> > >
> > For a given prefix, say ens2f0, can two UUID->sha1 first 9 characters have
> collision?
>
> I think it would be a mistake to waste so many chars on a prefix, but 9
> characters of sha1 likely wouldn't have a collision before we have 10s of
> thousands of devices. Thanks,
>
> Alex
Jiri, Dave,
Are you ok with it for devlink/netdev part?
Mdev core will create an alias from a UUID.
This will be supplied during devlink port attr set such as,
devlink_port_attrs_mdev_set(struct devlink_port *port, const char *mdev_alias);
This alias is used to generate representor netdev's phys_port_name.
This alias from the mdev device's sysfs will be used by the udev/systemd to generate predicable netdev's name.
Example: enm<mdev_alias_first_12_chars>
I took Ethernet mdev as an example.
New prefix 'm' stands for mediated device.
Remaining 12 characters are first 12 chars of the mdev alias.
next prev parent reply other threads:[~2019-08-21 6:23 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-02 6:59 [PATCH 0/2] Simplify mtty driver and mdev core Parav Pandit
2019-08-02 6:59 ` [PATCH 1/2] vfio-mdev/mtty: Simplify interrupt generation Parav Pandit
2019-08-06 8:15 ` Cornelia Huck
2019-08-02 6:59 ` [PATCH 2/2] vfio/mdev: Removed unused and redundant API for mdev name Parav Pandit
2019-08-06 8:29 ` Cornelia Huck
2019-08-06 13:12 ` Parav Pandit
2019-08-06 14:18 ` [PATCH v1 0/2] Simplify mtty driver and mdev core Parav Pandit
2019-08-06 14:18 ` [PATCH v1 1/2] vfio-mdev/mtty: Simplify interrupt generation Parav Pandit
2019-08-06 14:18 ` [PATCH v1 2/2] vfio/mdev: Removed unused and redundant API for mdev UUID Parav Pandit
2019-08-07 9:28 ` Cornelia Huck
2019-08-07 16:33 ` Parav Pandit
2019-08-08 8:29 ` Cornelia Huck
2019-08-08 14:01 ` Parav Pandit
2019-08-08 14:12 ` [PATCH v2 0/2] Simplify mtty driver and mdev core Parav Pandit
2019-08-08 14:12 ` [PATCH v2 1/2] vfio-mdev/mtty: Simplify interrupt generation Parav Pandit
2019-08-13 16:39 ` Christoph Hellwig
2019-08-23 20:48 ` Alex Williamson
2019-08-08 14:12 ` [PATCH v2 2/2] vfio/mdev: Removed unused and redundant API for mdev UUID Parav Pandit
2019-08-13 16:39 ` Christoph Hellwig
2019-08-16 15:22 ` Cornelia Huck
2019-08-08 23:02 ` [PATCH v2 0/2] Simplify mtty driver and mdev core Alex Williamson
2019-08-09 8:07 ` Cornelia Huck
2019-08-12 11:35 ` Kirti Wankhede
2019-08-13 14:40 ` Parav Pandit
2019-08-13 14:52 ` Alex Williamson
2019-08-13 16:28 ` Parav Pandit
2019-08-13 16:34 ` Cornelia Huck
2019-08-13 17:11 ` Alex Williamson
2019-08-14 5:54 ` Parav Pandit
2019-08-14 8:01 ` Cornelia Huck
2019-08-14 12:27 ` Parav Pandit
2019-08-14 13:09 ` Cornelia Huck
2019-08-14 13:45 ` Parav Pandit
2019-08-14 14:57 ` Alex Williamson
2019-08-14 16:21 ` Parav Pandit
2019-08-20 8:58 ` Parav Pandit
2019-08-20 9:58 ` Christophe de Dinechin
2019-08-20 11:25 ` Parav Pandit
2019-08-20 16:31 ` Cornelia Huck
2019-08-21 2:42 ` Parav Pandit
2019-08-20 17:19 ` Alex Williamson
2019-08-20 17:55 ` Cornelia Huck
2019-08-21 3:57 ` Parav Pandit
2019-08-21 3:42 ` Parav Pandit
2019-08-21 4:20 ` Alex Williamson
2019-08-21 4:40 ` Parav Pandit
2019-08-21 4:57 ` Alex Williamson
2019-08-21 5:01 ` Parav Pandit
2019-08-21 5:26 ` Alex Williamson
2019-08-21 6:23 ` Parav Pandit [this message]
2019-08-22 9:29 ` Jiri Pirko
2019-08-22 9:42 ` Parav Pandit
2019-08-22 9:58 ` Jiri Pirko
2019-08-22 10:04 ` Parav Pandit
2019-08-22 12:19 ` Jiri Pirko
2019-08-22 13:33 ` Parav Pandit
2019-08-23 8:12 ` Jiri Pirko
2019-08-23 8:14 ` Parav Pandit
2019-08-23 14:28 ` Alex Williamson
2019-08-23 14:53 ` Parav Pandit
2019-08-23 15:04 ` Jiri Pirko
2019-08-23 15:52 ` Alex Williamson
2019-08-23 16:14 ` Parav Pandit
2019-08-23 17:16 ` Alex Williamson
2019-08-23 18:00 ` Parav Pandit
2019-08-23 19:43 ` Alex Williamson
2019-08-24 3:56 ` Parav Pandit
2019-08-24 4:45 ` Parav Pandit
2019-08-24 4:59 ` Alex Williamson
2019-08-24 5:22 ` Parav Pandit
2019-08-13 16:37 ` Christoph Hellwig
2019-08-13 17:40 ` Greg Kroah-Hartman
2019-08-14 5:30 ` Parav Pandit
2019-08-13 14:48 ` Parav Pandit
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=AM0PR05MB4866437FAA63C447CACCD7E5D1AA0@AM0PR05MB4866.eurprd05.prod.outlook.com \
--to=parav@mellanox.com \
--cc=alex.williamson@redhat.com \
--cc=cjia@nvidia.com \
--cc=cohuck@redhat.com \
--cc=davem@davemloft.net \
--cc=jiri@mellanox.com \
--cc=kvm@vger.kernel.org \
--cc=kwankhede@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).