drm/i915: Stash a pointer to the obj's resv in the vma

During execbuf, a mandatory step is that we add this request (this
fence) to each object's reservation_object. Inside execbuf, we track the
vma, and to add the fence to the reservation_object then means having to
first chase the obj, incurring another cache miss. We can reduce the
 number of cache misses by stashing a pointer to the reservation_object
in the vma itself.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170616140525.6394-1-chris@chris-wilson.co.uk

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index f5c57dff288e..532c709febbd 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -90,6 +90,7 @@ vma_create(struct drm_i915_gem_object *obj,
 	init_request_active(&vma->last_fence, NULL);
 	vma->vm = vm;
 	vma->obj = obj;
+	vma->resv = obj->resv;
 	vma->size = obj->base.size;
 	vma->display_alignment = I915_GTT_MIN_ALIGNMENT;