[Intel-gfx] [PATCH 01/22] drm/i915/gem: Make caps.scheduler static

[Chris Wilson]

Quoting Mika Kuoppala (2019-08-06 11:40:48)
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> > diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> > index 8ac7d14ec8c9..81094f250bdb 100644
> > --- a/drivers/gpu/drm/i915/i915_request.c
> > +++ b/drivers/gpu/drm/i915/i915_request.c
> > @@ -1198,7 +1198,6 @@ struct i915_request *__i915_request_commit(struct i915_request *rq)
> >        */
> >       local_bh_disable();
> >       i915_sw_fence_commit(&rq->semaphore);
> > -     rcu_read_lock(); /* RCU serialisation for set-wedged protection */
> 
> We don't need to protect against attr changes anymore so yes...
> 
> >       if (engine->schedule) {
> >               struct i915_sched_attr attr = rq->gem_context->sched;
> >  
> > @@ -1228,7 +1227,6 @@ struct i915_request *__i915_request_commit(struct i915_request *rq)
> >  
> >               engine->schedule(rq, &attr);
> 
> but will now schedule during wedged. Didn't notice anything that
> would blowup on reordering but is this intentional?

How do you think it will blow up? engine->schedule remains untouched
over wedged, and all it is doing is traversing the dependency lists
(which remain intact) and the scheduler list (which is controlled by
locking and cleared inside engine->cancel_requests, after which point it
will remain clear as nop_submit_request should not care).

I don't think there's a bad interaction there between i915_schedule()
and nop_submit_request...
-Chris