From: Jason Gunthorpe <jgg@ziepe.ca>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Alexander Duyck <alexander.duyck@gmail.com>,
Keith Busch <kbusch@kernel.org>,
Leon Romanovsky <leon@kernel.org>,
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>,
Alex Williamson <alex.williamson@redhat.com>,
"David S . Miller" <davem@davemloft.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH mlx5-next v7 0/4] Dynamically assign MSI-X vectors count
Date: Tue, 30 Mar 2021 19:43:41 -0300 [thread overview]
Message-ID: <20210330224341.GW2710221@ziepe.ca> (raw)
In-Reply-To: <20210330204141.GA1305530@bjorn-Precision-5520>
On Tue, Mar 30, 2021 at 03:41:41PM -0500, Bjorn Helgaas wrote:
> On Tue, Mar 30, 2021 at 04:47:16PM -0300, Jason Gunthorpe wrote:
> > On Tue, Mar 30, 2021 at 10:00:19AM -0500, Bjorn Helgaas wrote:
> > > On Tue, Mar 30, 2021 at 10:57:38AM -0300, Jason Gunthorpe wrote:
> > > > On Mon, Mar 29, 2021 at 08:29:49PM -0500, Bjorn Helgaas wrote:
> > > >
> > > > > I think I misunderstood Greg's subdirectory comment. We already have
> > > > > directories like this:
> > > >
> > > > Yes, IIRC, Greg's remark applies if you have to start creating
> > > > directories with manual kobjects.
> > > >
> > > > > and aspm_ctrl_attr_group (for "link") is nicely done with static
> > > > > attributes. So I think we could do something like this:
> > > > >
> > > > > /sys/bus/pci/devices/0000:01:00.0/ # PF directory
> > > > > sriov/ # SR-IOV related stuff
> > > > > vf_total_msix
> > > > > vf_msix_count_BB:DD.F # includes bus/dev/fn of first VF
> > > > > ...
> > > > > vf_msix_count_BB:DD.F # includes bus/dev/fn of last VF
> > > >
> > > > It looks a bit odd that it isn't a subdirectory, but this seems
> > > > reasonable.
> > >
> > > Sorry, I missed your point; you'll have to lay it out more explicitly.
> > > I did intend that "sriov" *is* a subdirectory of the 0000:01:00.0
> > > directory. The full paths would be:
> > >
> > > /sys/bus/pci/devices/0000:01:00.0/sriov/vf_total_msix
> > > /sys/bus/pci/devices/0000:01:00.0/sriov/vf_msix_count_BB:DD.F
> > > ...
> >
> > Sorry, I was meaning what you first proposed:
> >
> > /sys/bus/pci/devices/0000:01:00.0/sriov/BB:DD.F/vf_msix_count
> >
> > Which has the extra sub directory to organize the child VFs.
> >
> > Keep in mind there is going to be alot of VFs here, > 1k - so this
> > will be a huge directory.
>
> With 0000:01:00.0/sriov/vf_msix_count_BB:DD.F, sriov/ will contain
> 1 + 1K files ("vf_total_msix" + 1 per VF).
>
> With 0000:01:00.0/sriov/BB:DD.F/vf_msix_count, sriov/ will contain
> 1 file and 1K subdirectories.
The smallest directory sizes is with the current patch since it
re-uses the existing VF directory. Do we care about directory size at
the sysfs level?
> No real difference now, but if we add more files per VF, a BB:DD.F/
> subdirectory would certainly be nicer.
Hard to know if that will happen, there is a lot of 'pre-driver'
configuration but it seems to mostly be living in other places.
If this is restricted to be only the generic PCI attributes (and I
think it should be) I'm having a hard time coming up with a future
extension.
> I'm dense and don't fully understand Greg's subdirectory comment.
I also don't know udev well enough. I've certainly seen drivers
creating extra subdirectories using kobjects.
> But it doesn't seem like that level of control would be in a udev rule
> anyway. A PF udev rule might *start* a program to manage MSI-X
> vectors, but such a program should be able to deal with whatever
> directory structure we want.
Yes, I can't really see this being used from udev either.
I assume there is also the usual race about triggering the uevent
before the subdirectories are created, but we have the
dev_set_uevent_suppress() thing now for that..
Jason
next prev parent reply other threads:[~2021-03-30 22:44 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 7:55 [PATCH mlx5-next v7 0/4] Dynamically assign MSI-X vectors count Leon Romanovsky
2021-03-01 7:55 ` [PATCH mlx5-next v7 1/4] PCI: Add a sysfs file to change the MSI-X table size of SR-IOV VFs Leon Romanovsky
2021-03-01 8:14 ` Greg Kroah-Hartman
2021-03-01 8:32 ` Leon Romanovsky
2021-03-01 8:37 ` Greg Kroah-Hartman
2021-03-01 8:53 ` Leon Romanovsky
2021-03-01 7:55 ` [PATCH mlx5-next v7 2/4] net/mlx5: Add dynamic MSI-X capabilities bits Leon Romanovsky
2021-03-01 7:55 ` [PATCH mlx5-next v7 3/4] net/mlx5: Dynamically assign MSI-X vectors count Leon Romanovsky
2021-03-01 7:55 ` [PATCH mlx5-next v7 4/4] net/mlx5: Implement sriov_get_vf_total_msix/count() callbacks Leon Romanovsky
2021-03-07 8:11 ` [PATCH mlx5-next v7 0/4] Dynamically assign MSI-X vectors count Leon Romanovsky
2021-03-07 18:55 ` Alexander Duyck
2021-03-07 19:19 ` Leon Romanovsky
2021-03-08 16:33 ` Alexander Duyck
2021-03-08 19:20 ` Leon Romanovsky
2021-03-10 19:09 ` Bjorn Helgaas
2021-03-10 20:10 ` Leon Romanovsky
2021-03-10 20:21 ` Greg Kroah-Hartman
2021-03-11 8:37 ` Leon Romanovsky
2021-03-10 23:34 ` Alexander Duyck
2021-03-11 18:17 ` Bjorn Helgaas
2021-03-11 19:16 ` Keith Busch
2021-03-11 19:21 ` Leon Romanovsky
2021-03-11 20:22 ` Jason Gunthorpe
2021-03-11 20:50 ` Keith Busch
2021-03-11 21:44 ` Jason Gunthorpe
2021-03-25 17:21 ` Bjorn Helgaas
2021-03-25 17:36 ` Jason Gunthorpe
2021-03-25 18:20 ` Bjorn Helgaas
2021-03-25 18:28 ` Jason Gunthorpe
2021-03-26 6:44 ` Leon Romanovsky
2021-03-26 16:00 ` Alexander Duyck
2021-03-26 16:56 ` Jason Gunthorpe
2021-03-26 17:08 ` Bjorn Helgaas
2021-03-26 17:12 ` Jason Gunthorpe
2021-03-27 6:00 ` Leon Romanovsky
2021-03-26 17:29 ` Keith Busch
2021-03-26 17:31 ` Jason Gunthorpe
2021-03-26 18:50 ` Alexander Duyck
2021-03-26 19:01 ` Jason Gunthorpe
2021-03-30 1:29 ` Bjorn Helgaas
2021-03-30 13:57 ` Jason Gunthorpe
2021-03-30 15:00 ` Bjorn Helgaas
2021-03-30 19:47 ` Jason Gunthorpe
2021-03-30 20:41 ` Bjorn Helgaas
2021-03-30 22:43 ` Jason Gunthorpe [this message]
2021-03-31 6:38 ` Greg Kroah-Hartman
2021-03-31 12:19 ` Jason Gunthorpe
2021-03-31 15:03 ` Greg Kroah-Hartman
2021-03-31 17:07 ` Jason Gunthorpe
2021-03-31 4:08 ` Leon Romanovsky
2021-04-01 1:23 ` Bjorn Helgaas
2021-04-01 11:49 ` Leon Romanovsky
2021-03-30 18:10 ` Keith Busch
2021-03-26 19:36 ` Bjorn Helgaas
2021-03-27 12:38 ` Greg Kroah-Hartman
2021-03-25 18:31 ` Keith Busch
2021-03-25 18:36 ` Jason Gunthorpe
2021-03-11 19:17 ` Leon Romanovsky
2021-03-11 19:37 ` Alexander Duyck
2021-03-11 19:51 ` Leon Romanovsky
2021-03-11 20:11 ` Alexander Duyck
2021-03-11 20:19 ` Jason Gunthorpe
2021-03-11 21:49 ` Alexander Duyck
2021-03-11 23:20 ` Jason Gunthorpe
2021-03-12 2:53 ` Alexander Duyck
2021-03-12 6:32 ` Leon Romanovsky
2021-03-12 16:59 ` Alexander Duyck
2021-03-12 17:03 ` Jason Gunthorpe
2021-03-12 18:34 ` Leon Romanovsky
2021-03-12 18:41 ` Leon Romanovsky
2021-03-12 13:00 ` Jason Gunthorpe
2021-03-12 13:36 ` Keith Busch
2021-03-11 20:31 ` Jason Gunthorpe
2021-03-10 5:58 ` Leon Romanovsky
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