[Intel-gfx] [PATCH v7 2/3] drm/i915/ttm: Adjust gem flags and caching settings after a move

[Matthew Auld]

On Tue, 22 Jun 2021 at 10:34, Thomas Hellström
<thomas.hellstrom at linux.intel.com> wrote:
>
> After a TTM move or object init we need to update the i915 gem flags and
> caching settings to reflect the new placement. Currently caching settings
> are not changed during the lifetime of an object, although that might
> change moving forward if we run into performance issues or issues with
> WC system page allocations.
> Also introduce gpu_binds_iomem() and cpu_maps_iomem() to clean up the
> various ways we previously used to detect this.
> Finally, initialize the TTM object reserved to be able to update
> flags and caching before anyone else gets hold of the object.
>
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
> ---
> v6:
> - Rebase on accelerated ttm moves.
> ---

<snip>

> @@ -775,14 +845,13 @@ int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
>         i915_gem_object_init(obj, &i915_gem_ttm_obj_ops, &lock_class, flags);
>         i915_gem_object_init_memory_region(obj, mem);
>         i915_gem_object_make_unshrinkable(obj);
> -       obj->read_domains = I915_GEM_DOMAIN_WC | I915_GEM_DOMAIN_GTT;
> -       obj->mem_flags |= I915_BO_FLAG_IOMEM;
> -       i915_gem_object_set_cache_coherency(obj, I915_CACHE_NONE);
>         INIT_RADIX_TREE(&obj->ttm.get_io_page.radix, GFP_KERNEL | __GFP_NOWARN);
>         mutex_init(&obj->ttm.get_io_page.lock);
>         bo_type = (obj->flags & I915_BO_ALLOC_USER) ? ttm_bo_type_device :
>                 ttm_bo_type_kernel;
>
> +       obj->base.vma_node.driver_private = i915_gem_to_ttm(obj);
> +
>         /*
>          * If this function fails, it will call the destructor, but
>          * our caller still owns the object. So no freeing in the
> @@ -790,14 +859,16 @@ int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
>          * Similarly, in delayed_destroy, we can't call ttm_bo_put()
>          * until successful initialization.
>          */
> -       obj->base.vma_node.driver_private = i915_gem_to_ttm(obj);
> -       ret = ttm_bo_init(&i915->bdev, i915_gem_to_ttm(obj), size,
> -                         bo_type, &i915_sys_placement,
> -                         mem->min_page_size >> PAGE_SHIFT,
> -                         true, NULL, NULL, i915_ttm_bo_destroy);
> -       if (!ret)
> -               obj->ttm.created = true;
> -
> -       /* i915 wants -ENXIO when out of memory region space. */
> -       return i915_ttm_err_to_gem(ret);
> +       ret = ttm_bo_init_reserved(&i915->bdev, i915_gem_to_ttm(obj), size,
> +                                  bo_type, &i915_sys_placement, 1,

mem->min_page_size >> PAGE_SHIFT? Although just realised that looks
iffy since it only considers the current region, when it should
consider all future placements. I wonder if it makes sense to make
page_alignment part of ttm_place? Anyway, it doesn't matter for this
series.

> +                                  &ctx, NULL, NULL, i915_ttm_bo_destroy);
> +       if (ret)
> +               return i915_ttm_err_to_gem(ret);
> +
> +       obj->ttm.created = true;
> +       i915_ttm_adjust_domains_after_move(obj);
> +       i915_ttm_adjust_gem_after_move(obj);
> +       i915_gem_object_unlock(obj);
> +
> +       return 0;
>  }
> --
> 2.31.1
>
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