From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 9 Oct 2017 10:20:19 +0100
Subject: drm/i915: Assert we do not try to expand VMA for hugepage inside GGTT
Git-commit: bef27bdb6cfbc8c74c776f9455d4d3a4a76a4872
Patch-mainline: v4.15-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
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.
v2: After discussion with Matthew, make it a blanket GGTT ban
(previously we allowed the expansion for appgtt, and so indirectly
ggtt). There are issues we need to fix before allowing the current
appgtt to be used with hugepages, and if we do, we probably want more
care over when to expand/align, as the mappable aperture inside the ggtt
is precious.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171009092019.20747-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/i915/i915_vma.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -513,6 +513,13 @@ i915_vma_insert(struct i915_vma *vma, u6
rounddown_pow_of_two(vma->page_sizes.sg |
I915_GTT_PAGE_SIZE_2M);
+ /*
+ * Check we don't expand for the limited Global GTT
+ * (mappable aperture is even more precious!). This
+ * also checks that we exclude the aliasing-ppgtt.
+ */
+ GEM_BUG_ON(i915_vma_is_ggtt(vma));
+
alignment = max(alignment, page_alignment);
if (vma->page_sizes.sg & I915_GTT_PAGE_SIZE_64K)