From bef27bdb6cfbc8c74c776f9455d4d3a4a76a4872 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 9 Oct 2017 10:20:19 +0100 Subject: [PATCH] drm/i915: Assert we do not try to expand VMA for hugepage inside GGTT 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 Cc: Matthew Auld Cc: Joonas Lahtinen Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20171009092019.20747-1-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen --- drivers/gpu/drm/i915/i915_vma.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 72e86b32ab41..2bad88cc927b 100644 --- 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, u64 size, u64 alignment, u64 flags) 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) -- GitLab