drm/i915: Store i915_gem_object_is_coherent() as a bit next to cache-dirty

For ease of use (i.e. avoiding a few checks and function calls), store
the object's cache coherency next to the cache is dirty bit.

Specifically this patch aims to reduce the frequency of no-op calls to
i915_gem_object_clflush() to counter-act the increase of such calls for
GPU only objects in the previous patch.

v2: Replace cache_dirty & ~cache_coherent with cache_dirty &&
!cache_coherent as gcc generates much better code for the latter
(Tvrtko)

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Tested-by: Dongwon Kim <dongwon.kim@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170616105455.16977-1-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_clflush.c b/drivers/gpu/drm/i915/i915_gem_clflush.c
index 17b207e..152f16c 100644
--- a/drivers/gpu/drm/i915/i915_gem_clflush.c
+++ b/drivers/gpu/drm/i915/i915_gem_clflush.c
@@ -139,7 +139,7 @@ void i915_gem_clflush_object(struct drm_i915_gem_object *obj,
 	 * snooping behaviour occurs naturally as the result of our domain
 	 * tracking.
 	 */
-	if (!(flags & I915_CLFLUSH_FORCE) && i915_gem_object_is_coherent(obj))
+	if (!(flags & I915_CLFLUSH_FORCE) && obj->cache_coherent)
 		return;
 
 	trace_i915_gem_object_clflush(obj);