From: Leon Romanovsky <leon@kernel.org>
To: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>,
Alex Williamson <alex.williamson@redhat.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Saeed Mahameed <saeedm@nvidia.com>,
Jakub Kicinski <kuba@kernel.org>,
linux-pci <linux-pci@vger.kernel.org>,
linux-rdma@vger.kernel.org, Netdev <netdev@vger.kernel.org>,
Don Dutile <ddutile@redhat.com>
Subject: Re: [PATCH mlx5-next v1 2/5] PCI: Add SR-IOV sysfs entry to read number of MSI-X vectors
Date: Tue, 19 Jan 2021 07:43:46 +0200 [thread overview]
Message-ID: <20210119054346.GD21258@unreal> (raw)
In-Reply-To: <CAKgT0UeYb5xz8iehE1Y0s-cyFbsy46bjF83BkA7qWZMkAOLR-g@mail.gmail.com>
On Mon, Jan 18, 2021 at 10:21:03AM -0800, Alexander Duyck wrote:
> On Mon, Jan 18, 2021 at 5:28 AM Leon Romanovsky <leon@kernel.org> wrote:
> >
> > On Mon, Jan 18, 2021 at 09:20:08AM +0200, Leon Romanovsky wrote:
> > > On Sun, Jan 17, 2021 at 07:16:30PM -0800, Alexander Duyck wrote:
> > > > On Sat, Jan 16, 2021 at 12:20 AM Leon Romanovsky <leon@kernel.org> wrote:
> > > > >
> > > > > On Fri, Jan 15, 2021 at 05:48:59PM -0800, Alexander Duyck wrote:
> > > > > > On Fri, Jan 15, 2021 at 7:53 AM Leon Romanovsky <leon@kernel.org> wrote:
> > > > > > >
> > > > > > > On Fri, Jan 15, 2021 at 10:06:19AM -0400, Jason Gunthorpe wrote:
> > > > > > > > On Thu, Jan 14, 2021 at 05:56:20PM -0800, Alexander Duyck wrote:
> >
> > <...>
> >
> > > > If you want yet another compromise I would be much happier with the PF
> > > > registering the sysfs interfaces on the VFs rather than the VFs
> > > > registering the interface and hoping the PF supports it. At least with
> > > > that you are guaranteed the PF will respond to the interface when it
> > > > is registered.
> > >
> > > Thanks a lot, I appreciate it, will take a look now.
> >
> > I found only two solutions to implement it in this way.
> > Option 1.
> > Allow multi entry write to some new sysfs knob that will receive BDF (or another VF
> > identification) and vector count. Something like this:
> >
> > echo "0000:01:00.2 123" > sriov_vf_msix_count
> >
> > From one side, that solution is unlikely to be welcomed by Greg KH and from another,
> > it will require a lot of boilerplate code to make it safe and correct.
>
> You are overthinking this. I didn't say the sysfs had to be in the PF
> directory itself. My request was that the PF is what placed the sysfs
> file in the directory since indirectly it is responsible for spawning
> the VF anyway it shouldn't be too much of a lift to have the PF place
> sysfs files in the VF hierarchy.
>
> The main piece I am not a fan of is the fact that the VF is blindly
> registering an interface and presenting it without knowing if it even
> works.
>
> The secondary issue that I see as important, but I am willing to
> compromise on is that the interface makes it appear as though the VF
> configuration space is writable via this sysfs file. My preference
> would be to somehow make it transparent that the PF is providing this
> functionality. I thought it might be easier to do with devlink rather
> than with sysfs which is why I have been preferring devlink. However
> based on your pushback I am willing to give up on that, but I think we
> still need to restructure how the sysfs is being managed.
>
> > Option 2.
> > Create directory under PF device with files writable and organized by VF numbers.
> > It is doable, but will cause to code bloat with no gain at all. Cleaner than now,
> > it won't be.
> >
> > Why the current approach with one file per-proper VF device is not good enough?
>
> Because it is muddying the waters in terms of what is control taking
> place from the VF versus the PF. In my mind the ideal solution if you
> insist on going with the VF sysfs route would be to look at spawning a
> directory inside the VF sysfs specifically for all of the instances
> that will be PF management controls. At least that would give some
> hint that this is a backdoor control and not actually interacting with
> the VF PCI device directly. Then if in the future you have to add more
> to this you have a spot already laid out and the controls won't be
> mistaken for standard PCI controls as they are PF management controls.
>
> In addition you could probably even create a directory on the PF with
> the new control you had added for getting the master count as well as
> look at adding symlinks to the VF files so that you could manage all
> of the resources in one spot. That would result in the controls being
> nicely organized and easy to use.
Thanks, for you inputs.
I'll try offline different variants and will post v4 soon.
next prev parent reply other threads:[~2021-01-19 6:21 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-10 15:07 [PATCH mlx5-next v1 0/5] Dynamically assign MSI-X vectors count Leon Romanovsky
2021-01-10 15:07 ` [PATCH mlx5-next v1 1/5] PCI: Add sysfs callback to allow MSI-X table size change of SR-IOV VFs Leon Romanovsky
2021-01-11 19:30 ` Alexander Duyck
2021-01-12 3:25 ` Don Dutile
2021-01-12 6:15 ` Leon Romanovsky
2021-01-12 6:39 ` Leon Romanovsky
2021-01-12 21:59 ` Alexander Duyck
2021-01-13 6:09 ` Leon Romanovsky
2021-01-13 20:00 ` Alexander Duyck
2021-01-14 7:16 ` Leon Romanovsky
2021-01-14 16:51 ` Alexander Duyck
2021-01-14 17:12 ` Leon Romanovsky
2021-01-13 17:50 ` Alex Williamson
2021-01-13 19:49 ` Leon Romanovsky
2021-01-10 15:07 ` [PATCH mlx5-next v1 2/5] PCI: Add SR-IOV sysfs entry to read number of MSI-X vectors Leon Romanovsky
2021-01-11 19:30 ` Alexander Duyck
2021-01-12 6:56 ` Leon Romanovsky
2021-01-12 21:34 ` Alexander Duyck
2021-01-13 6:19 ` Leon Romanovsky
2021-01-13 22:44 ` Alexander Duyck
2021-01-14 6:50 ` Leon Romanovsky
2021-01-14 16:40 ` Alexander Duyck
2021-01-14 16:48 ` Jason Gunthorpe
2021-01-14 17:55 ` Alexander Duyck
2021-01-14 18:29 ` Jason Gunthorpe
2021-01-14 19:24 ` Alexander Duyck
2021-01-14 19:56 ` Leon Romanovsky
2021-01-14 20:08 ` Jason Gunthorpe
2021-01-14 21:43 ` Alexander Duyck
2021-01-14 23:28 ` Alex Williamson
2021-01-15 1:56 ` Alexander Duyck
2021-01-15 14:06 ` Jason Gunthorpe
2021-01-15 15:53 ` Leon Romanovsky
2021-01-16 1:48 ` Alexander Duyck
2021-01-16 8:20 ` Leon Romanovsky
2021-01-18 3:16 ` Alexander Duyck
2021-01-18 7:20 ` Leon Romanovsky
2021-01-18 13:28 ` Leon Romanovsky
2021-01-18 18:21 ` Alexander Duyck
2021-01-19 5:43 ` Leon Romanovsky [this message]
2021-01-16 4:32 ` Alexander Duyck
2021-01-18 15:47 ` Jason Gunthorpe
2021-01-15 13:51 ` Jason Gunthorpe
2021-01-14 17:26 ` Leon Romanovsky
2021-01-18 17:03 ` Greg KH
2021-01-19 5:38 ` Leon Romanovsky
2021-01-10 15:07 ` [PATCH mlx5-next v1 3/5] net/mlx5: Add dynamic MSI-X capabilities bits Leon Romanovsky
2021-01-10 15:07 ` [PATCH mlx5-next v1 4/5] net/mlx5: Dynamically assign MSI-X vectors count Leon Romanovsky
2021-01-10 15:07 ` [PATCH mlx5-next v1 5/5] net/mlx5: Allow to the users to configure number of MSI-X vectors Leon Romanovsky
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=20210119054346.GD21258@unreal \
--to=leon@kernel.org \
--cc=alex.williamson@redhat.com \
--cc=alexander.duyck@gmail.com \
--cc=bhelgaas@google.com \
--cc=ddutile@redhat.com \
--cc=jgg@nvidia.com \
--cc=kuba@kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=linux-rdma@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=saeedm@nvidia.com \
/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).