[Intel-gfx] [PATCH 02/11] drm/i915/gtt: Teach restore-gtt to walk the ggtt vma list not the object list

[Joonas Lahtinen]

Quoting Chris Wilson (2018-06-05 10:19:40)
> In preparation, for having non-vma objects stored inside the ggtt, to
> handle restoration of the GGTT following resume, we need to walk over
> the ggtt address space rebinding vma, as opposed to walking over bound
> objects looking for ggtt entries.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> Cc: Matthew Auld <matthew.william.auld at gmail.com>

Comment below.

Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>

> @@ -3578,21 +3578,15 @@ void i915_gem_restore_gtt_mappings(struct drm_i915_private *dev_priv)
>         ggtt->vm.closed = true; /* skip rewriting PTE on VMA unbind */
>  
>         /* clflush objects bound into the GGTT and rebind them. */
> -       list_for_each_entry_safe(obj, on, &dev_priv->mm.bound_list, mm.link) {
> -               bool ggtt_bound = false;
> -               struct i915_vma *vma;
> -
> -               for_each_ggtt_vma(vma, obj) {
> -                       if (!i915_vma_unbind(vma))
> -                               continue;
> +       GEM_BUG_ON(!list_empty(&ggtt->vm.active_list));
> +       list_for_each_entry_safe(vma, vn, &ggtt->vm.inactive_list, vm_link) {
> +               struct drm_i915_gem_object *obj = vma->obj;
>  
> -                       WARN_ON(i915_vma_bind(vma, obj->cache_level,
> -                                             PIN_UPDATE));
> -                       ggtt_bound = true;
> -               }
> +               if (!i915_vma_unbind(vma))
> +                       continue;
>  
> -               if (ggtt_bound)
> -                       WARN_ON(i915_gem_object_set_to_gtt_domain(obj, false));
> +               WARN_ON(i915_vma_bind(vma, obj->cache_level, PIN_UPDATE));
> +               WARN_ON(i915_gem_object_set_to_gtt_domain(obj, false));

This gets called multiple times per an object for partial and rotated
views, but that should not be our performance bottleneck.

Regards, Joonas