[Intel-gfx] [PATCH] drm/i915/gtt: Skip initializing PT with scratch if full

[Chris Wilson]

If we will completely overwrite the PT with PTEs for the object, we can
forgo filling it with scratch entries.

References: 14826673247e ("drm/i915: Only initialize partially filled pagetables")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Cc: Matthew Auld <matthew.william.auld at gmail.com>
Reviewed-by: Matthew Auld <matthew.william.auld at gmail.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index daecbf91efc6..6f437b28fe2a 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1846,7 +1846,8 @@ static int gen6_alloc_va_range(struct i915_address_space *vm,
 			if (IS_ERR(pt))
 				goto unwind_out;
 
-			gen6_initialize_pt(vm, pt);
+			if (count < GEN6_PTES)
+				gen6_initialize_pt(vm, pt);
 
 			old = cmpxchg(&ppgtt->base.pd.page_table[pde],
 				      vm->scratch_pt, pt);
-- 
2.20.1