[Intel-gfx] [PATCH v2] drm/i915: make context status notifier head be per engine

[Chris Wilson]

On Mon, Mar 13, 2017 at 12:03:30PM +0800, Zhenyu Wang wrote:
> On 2017.03.13 10:47:11 +0800, changbin.du at intel.com wrote:
> > From: Changbin Du <changbin.du at intel.com>
> > 
> > GVTg has introduced the context status notifier to schedule the GVTg
> > workload. At that time, the notifier is bound to GVTg context only,
> > so GVTg is not aware of host workloads.
> > 
> > Now we are going to improve GVTg's guest workload scheduler policy,
> > and add Guc emulation support for new Gen graphics. Both these two
> > features require acknowledgment for all contexts running on hardware.
> > (But will not alter host workload.) So here try to make some change.
> > 
> > The change is simple:
> >   1. Move the context status notifier head from i915_gem_context to
> >      intel_engine_cs. Which means there is a notifier head per engine
> >      instead of per context. Execlist driver still call notifier for
> >      each context sched-in/out events of current engine.
> >   2. At GVTg side, it binds a notifier_block for each physical engine
> >      at GVTg initialization period. Then GVTg can hear all context
> >      status events.
> > 
> > In this patch, GVTg do nothing for host context event, but later
> > will add a function there. But in any case, the notifier callback is
> > a noop if this is no active vGPU.
> > 
> > Since intel_gvt_init() is called at early initialization stage and
> > require the status notifier head has been initiated, I initiate it in
> > intel_engine_setup().
> > 
> > v2: remove a redundant newline. (chris)
> > 
> > Signed-off-by: Changbin Du <changbin.du at intel.com>
> > Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> 
> Applied to gvt-next, thanks!

It turns out this fixes a use-after-free bug that CI was falling over.
Applied to dinq.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100232
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre