[Intel-gfx] [PATCH 6/6] drm/i915: Migrate stolen objects before hibernation

[Chris Wilson]

On Wed, Nov 11, 2015 at 04:06:13PM +0530, ankitprasad.r.sharma at intel.com wrote:
> +swap_pages:
> +	stolen_pages = obj->pages;
> +	obj->pages = NULL;
> +
> +	obj->base.filp = file;
> +	obj->base.read_domains = I915_GEM_DOMAIN_CPU;
> +	obj->base.write_domain = I915_GEM_DOMAIN_CPU;
> +
> +	/* Recreate any pinned binding with pointers to the new storage */
> +	if (!list_empty(&obj->vma_list)) {
> +		ret = i915_gem_object_get_pages_gtt(obj);
> +		if (ret) {
> +			obj->pages = stolen_pages;
> +			goto err_file;
> +		}
> +
> +		ret = i915_gem_gtt_prepare_object(obj);
> +		if (ret) {
> +			i915_gem_object_put_pages_gtt(obj);
> +			obj->pages = stolen_pages;
> +			goto err_file;
> +		}

i915_gem_gtt_prepare_object() has been moved into
i915_gem_object_get_pages_gtt() so we can skip the call here.

> +
> +		ret = i915_gem_object_set_to_gtt_domain(obj, true);
> +		if (ret) {
> +			i915_gem_gtt_finish_object(obj);

Ditto.

> +int
> +i915_gem_freeze(struct drm_device *dev)
> +{
> +	/* Called before i915_gem_suspend() when hibernating */
> +	struct drm_i915_private *i915 = to_i915(dev);
> +	struct drm_i915_gem_object *obj, *tmp;
> +	struct list_head *phase[] = {
> +		&i915->mm.unbound_list, &i915->mm.bound_list, NULL
> +	}, **p;

ret = i915_mutex_lock_interruptible(dev);
if (ret) return ret;

> +
> +	/* Across hibernation, the stolen area is not preserved.
> +	 * Anything inside stolen must copied back to normal
> +	 * memory if we wish to preserve it.
> +	 */
> +	for (p = phase; *p; p++) {
> +		struct list_head migrate;
> +		int ret;
> +
> +		INIT_LIST_HEAD(&migrate);
> +		list_for_each_entry_safe(obj, tmp, *p, global_list) {
> +			if (obj->stolen == NULL)
> +				continue;
> +
> +			if (obj->internal_volatile)
> +				continue;
> +
> +			/* In the general case, this object may only be alive
> +			 * due to an active reference, and that may disappear
> +			 * when we unbind any of the objects (and so wait upon
> +			 * the GPU and retire requests). To prevent one of the
> +			 * objects from disappearing beneath us, we need to
> +			 * take a reference to each as we build the migration
> +			 * list.
> +			 *
> +			 * This is similar to the strategy required whilst
> +			 * shrinking or evicting objects (for the same reason).
> +			 */
> +			drm_gem_object_reference(&obj->base);
> +			list_move(&obj->global_list, &migrate);
> +		}
> +
> +		ret = 0;
> +		list_for_each_entry_safe(obj, tmp, &migrate, global_list) {
> +			if (ret == 0)
> +				ret = i915_gem_object_migrate_stolen_to_shmemfs(obj);
> +			drm_gem_object_unreference(&obj->base);
> +		}
> +		list_splice(&migrate, *p);
> +		if (ret)
			break;
> +	}

mutex_unlock(&dev->struct_mutex;

> +
> +	return 0;
return ret;
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre