[Intel-gfx] [PATCH 2/2] drm/i915: Drop i915_gem_obj_is_pinned() from set-cache-level

[Daniel Vetter]

On Tue, Oct 06, 2015 at 11:39:56AM +0100, Chris Wilson wrote:
> Since the remove of the pin-ioctl, we only care about not changing the
> cache level on buffers pinned to the hardware as indicated by
> obj->pin_display. So we can safely replace i915_gem_object_is_pinned()
> here with a plain obj->pin_display check. During rebinding, we will check
> sanity checks in case vma->pin_count is erroneously set.
> 
> At the same time, we can micro-optimise GTT mmap() behaviour since we
> only need to relinquish the mmaps before Sandybridge.

Actual condition is !LLC so would need to be updated (and split out imo).
 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 40 ++++++++++++++++++++++++----------------
>  1 file changed, 24 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index d4a3bdf0c5b6..2b8ed7a2faab 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3629,31 +3629,34 @@ int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj,
>  {
>  	struct drm_device *dev = obj->base.dev;
>  	struct i915_vma *vma, *next;
> +	bool bound = false;
>  	int ret = 0;
>  
>  	if (obj->cache_level == cache_level)
>  		goto out;
>  
> -	if (i915_gem_obj_is_pinned(obj)) {
> -		DRM_DEBUG("can not change the cache level of pinned objects\n");
> -		return -EBUSY;
> -	}
> -
>  	list_for_each_entry_safe(vma, next, &obj->vma_list, vma_link) {
> +		if (!drm_mm_node_allocated(&vma->node))
> +			continue;
> +
> +		if (vma->pin_count) {
> +			DRM_DEBUG("can not change the cache level of pinned objects\n");
> +			return -EBUSY;
> +		}
> +
>  		if (!i915_gem_valid_gtt_space(vma, cache_level)) {
>  			ret = i915_vma_unbind(vma);
>  			if (ret)
>  				return ret;
> -		}
> +		} else
> +			bound = true;
>  	}
>  
> -	if (i915_gem_obj_bound_any(obj)) {
> +	if (bound) {
>  		ret = i915_gem_object_wait_rendering(obj, false);
>  		if (ret)
>  			return ret;

Shouldn't the below be split out into a separate patch? And maybe for
paranoia keep calling finish_gtt but restrict it to !LLC && snooped like
you do below.
-Daniel

>  
> -		i915_gem_object_finish_gtt(obj);
> -
>  		/* Before SandyBridge, you could not use tiling or fence
>  		 * registers with snooped memory, so relinquish any fences
>  		 * currently pointing to our region in the aperture.
> @@ -3664,13 +3667,18 @@ int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj,
>  				return ret;
>  		}
>  
> -		list_for_each_entry(vma, &obj->vma_list, vma_link)
> -			if (drm_mm_node_allocated(&vma->node)) {
> -				ret = i915_vma_bind(vma, cache_level,
> -						    PIN_UPDATE);
> -				if (ret)
> -					return ret;
> -			}
> +		/* Access to snoopable pages through the GTT is incoherent. */
> +		if (cache_level != I915_CACHE_NONE && !HAS_LLC(dev))
> +			i915_gem_release_mmap(obj);
> +
> +		list_for_each_entry(vma, &obj->vma_list, vma_link) {
> +			if (!drm_mm_node_allocated(&vma->node))
> +				continue;
> +
> +			ret = i915_vma_bind(vma, cache_level, PIN_UPDATE);
> +			if (ret)
> +				return ret;
> +		}
>  	}
>  
>  	list_for_each_entry(vma, &obj->vma_list, vma_link)
> -- 
> 2.6.0
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch