[PATCH v4 0/8] cgroup private data and DRM/i915 integration

[Matt Roper]

On Fri, Mar 23, 2018 at 02:15:38PM +0200, Joonas Lahtinen wrote:
> Quoting Matt Roper (2018-03-17 02:08:57)
> > This is the fourth iteration of the work previously posted here:
> >   (v1) https://lists.freedesktop.org/archives/intel-gfx/2018-January/153156.html
> >   (v2) https://www.mail-archive.com/dri-devel@lists.freedesktop.org/msg208170.html
> >   (v3) https://lists.freedesktop.org/archives/intel-gfx/2018-March/157928.html
> > 
> > The high level goal of this work is to allow non-cgroup-controller parts
> > of the kernel (e.g., device drivers) to register their own private
> > policy data for specific cgroups.  That mechanism is then made use of in
> > the i915 graphics driver to allow GPU priority to be assigned according
> > to the cgroup membership of the owning process.  Please see the v1 cover
> > letter linked above for a more in-depth explanation and justification.
> 
> Hi Matt,
> 
> For cross-subsystem changes such as this, it makes sense to Cc all
> relevant maintainers, especially if there have been previous comments to
> earlier revisions.
> 
> Please, do include and keep a reference to the userspace portion of the
> changes when you suggest new uAPI to be added. At least I have some trouble
> trying to track down the relevant interface consumer here.
> 
> I'm unsure how much sense it makes to commence with detailed i915 review
> if we will be blocked by lack of userspace after that? I'm assuming
> you've read through [1] already.

Hi Joonas,

I've sent the userspace code out a few times, but it looks like I forgot
to include a copy with v4/v4.5.  Here's the version I provided with v3:
  https://lists.freedesktop.org/archives/intel-gfx/2018-March/157935.html

Usually we don't consider things like i-g-t to be sufficient userspace
consumers because we need a real-world consumer rather than a "toy"
userspace.  However in this case, the i-g-t tool, although very simple,
is really the only userspace consumer I expect there to ever be.
Ultimately the true consumer of this cgroups work are bash scripts, sysv
init scripts, systemd recipes, etc.  that just need a very simple tool
to assign the specific values that make sense on a given system.
There's no expectation that graphics clients or display servers would
ever need to make use of these interfaces.



Matt

> 
> Regards, Joonas
> 
> [1] https://01.org/linuxgraphics/gfx-docs/drm/gpu/drm-uapi.html#open-source-userspace-requirements

-- 
Matt Roper
Graphics Software Engineer
IoTG Platform Enabling & Development
Intel Corporation
(916) 356-2795