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
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 537f502..c010304 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2661,7 +2661,10 @@ i915_gem_object_retire__read(struct i915_gem_active *active,
list_move_tail(&obj->global_list,
&request->i915->mm.bound_list);
- i915_gem_object_put(obj);
+ if (i915_gem_object_has_active_reference(obj)) {
+ i915_gem_object_clear_active_reference(obj);
+ i915_gem_object_put(obj);
+ }
}
static bool i915_context_is_banned(const struct i915_gem_context *ctx)
@@ -2935,6 +2938,12 @@ void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file)
list_for_each_entry_safe(vma, vn, &obj->vma_list, obj_link)
if (vma->vm->file == fpriv)
i915_vma_close(vma);
+
+ if (i915_gem_object_is_active(obj) &&
+ !i915_gem_object_has_active_reference(obj)) {
+ i915_gem_object_set_active_reference(obj);
+ i915_gem_object_get(obj);
+ }
mutex_unlock(&obj->base.dev->struct_mutex);
}
@@ -4475,6 +4484,17 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
intel_runtime_pm_put(dev_priv);
}
+void __i915_gem_object_release_unless_active(struct drm_i915_gem_object *obj)
+{
+ lockdep_assert_held(&obj->base.dev->struct_mutex);
+
+ GEM_BUG_ON(i915_gem_object_has_active_reference(obj));
+ if (i915_gem_object_is_active(obj))
+ i915_gem_object_set_active_reference(obj);
+ else
+ i915_gem_object_put(obj);
+}
+
int i915_gem_suspend(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = to_i915(dev);