[Intel-gfx] [PATCH 1/3] drm/i915: Assert we do not try to expand VMA for hugepage inside GGTT

[Chris Wilson]

We only apply the hugepage PD redirection inside the ppGTT, so during
i915_vma_insert() we want to exclude the GGTT from the additional
alignment constraints (thereby avoiding the extra GTT pressure from
fragmentation). Add an assert to document that intention alongside the
comment.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld at gmail.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_vma.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 72e86b32ab41..2d27027eaf85 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -513,6 +513,8 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 				rounddown_pow_of_two(vma->page_sizes.sg |
 						     I915_GTT_PAGE_SIZE_2M);
 
+			GEM_BUG_ON((flags & PIN_USER) == 0); /* No GGTT! */
+
 			alignment = max(alignment, page_alignment);
 
 			if (vma->page_sizes.sg & I915_GTT_PAGE_SIZE_64K)
-- 
2.14.2