[Intel-gfx] [PATCH 1/7] drm/i915: Don't use MI_STORE_DWORD_IMM on Sandybridge/vcs

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> Quoting Mika Kuoppala (2017-08-18 12:07:20)
>> Chris Wilson <chris at chris-wilson.co.uk> writes:
>> >       if (!eb->reloc_cache.vaddr &&
>> >           (DBG_FORCE_RELOC == FORCE_GPU_RELOC ||
>> > -          !reservation_object_test_signaled_rcu(vma->resv, true))) {
>> > +          !reservation_object_test_signaled_rcu(vma->resv, true)) &&
>> > +         __intel_engine_can_store_dword(eb->reloc_cache.gen,
>> > +                                        eb->engine->class)) {
>> >               const unsigned int gen = eb->reloc_cache.gen;
>> 
>> If you lift this to upper scope, you can make the check little
>> shorter. But incase you are avoiding the assignment to the latest,
>> i am not insisting.
>> 
>> There is engine in the eb so could you elaborate that
>> do we get by not doig intel_engine_can_store_dword(eb->engine)?
>
> I'm just partial to avoiding the pointer chasing. I want to make sure
> that the compiler/cpu see that we are reusing the gen, and prefer to
> keep the gen that we do use next to its friends inside
> eb->reloc_cache.

Ok.

Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>