drm/i915: Defer active reference until required

We only need the active reference to keep the object alive after the
handle has been deleted (so as to prevent a synchronous gem_close). Why
then pay the price of a kref on every execbuf when we can insert that
final active ref just in time for the handle deletion?

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/20161028125858.23563-6-chris@chris-wilson.co.uk

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 947d5ad51fb7..a3a364478a89 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3734,11 +3734,16 @@ void __iomem *i915_vma_pin_iomap(struct i915_vma *vma)
 void i915_vma_unpin_and_release(struct i915_vma **p_vma)
 {
 	struct i915_vma *vma;
+	struct drm_i915_gem_object *obj;
 
 	vma = fetch_and_zero(p_vma);
 	if (!vma)
 		return;
 
+	obj = vma->obj;
+
 	i915_vma_unpin(vma);
-	i915_vma_put(vma);
+	i915_vma_close(vma);
+
+	__i915_gem_object_release_unless_active(obj);
 }