[Intel-gfx] [RFC 3/4] drm/i915: Use new i915_gem_object_pin_map for LRC

[Chris Wilson]

On Mon, Apr 11, 2016 at 10:05:34AM +0100, Tvrtko Ursulin wrote:
> 
> On 08/04/16 15:40, Chris Wilson wrote:
> >On Fri, Apr 08, 2016 at 02:54:57PM +0100, Tvrtko Ursulin wrote:
> >>From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >>
> >>We can use the new pin/lazy unpin API for more performance
> >>in the execlist submission paths.
> >
> >The sticking point for me was the ringbuffer and Braswell having to
> >re-ioremap it every context pin. I hadn't noticed the kmap of the
> >context, but this does seem like a valid use for pin_map so I'm not
> >complaining... (Just saying this half the solution ;)
> 
> Pull in to the series "drm/i915: Move ioremap_wc tracking onto VMA"
> as well then?

That depends on "io-mapping: Specify mapping size for io_mapping_map_wc"
and the vma->map_and_fenceable (though you can workaround that) iirc .
 
> >Oh, and you don't have pin_map for your ringbuffer either yet.
> 
> Confused, I did base this on top of "drm/i915: Refactor duplicate
> object vmap functions" and the half missing is the ioremap paths.
> Which you commented on above. What other ringbuffer is missing?

No, I was just thinking it was still pending because I had a fixup in my
tree: drm/i915: Treat ringbuffer writes as write to normal memory

That and a patch to use WC vmaps for Braswell as well (that's still in
preliminary form, but if you are interested
https://cgit.freedesktop.org/~ickle/linux-2.6/commit/?h=tasklet&id=3fa97e044f3b5a2c23e44ec659a8199f134d8fb5
it really helps with context creation stress tests - and not much else!
;)
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre