[Intel-gfx] [PATCH] drm/i915: Avoid using mappable space for relocation processing through the CPU

[Ben Widawsky]

On Tue, Nov 29, 2011 at 03:12:40PM +0000, Chris Wilson wrote:
> We try to avoid writing the relocations through the uncached GTT, if the
> buffer is currently in the CPU write domain and so will be flushed out to
> main memory afterwards anyway. Also on SandyBridge we can safely write
> to the pages in cacheable memory, so long as the buffer is LLC mapped.
> In either of these caches, we therefore do not need to force the
> reallocation of the buffer into the mappable region of the GTT, reducing
> the aperture pressure.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Ben Widawsky <ben at bwidawsk.net>