[Intel-gfx] [PATCH v2 2/3] drm/i915: Assign I915_COLOR_UNEVICTABLE to the address space head_node

[Matthew Auld]

On 6 February 2017 at 08:45, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> The drm_mm range manager (within i915_address_space) uses a special
> drm_mm_node that excludes the unavailable range (beyond the end of the
> drm_mm). However, we play games with the global GTT to use the head_node
> to exclude the tail page but tell ourselves that the whole range is
> available. This causes an issue when we try to evict using the full
> range of the global GTT which is wider than the drm_mm, resulting in
> complete confusion and castrophe. One way to resolve this would be to
catastrophe

> use a reserved node to exclude the guard page, or we can treat the
> drm_mm's head_node as our guard page and assign it the appropriate
> colour.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld at intel.com>