From 2bf0d26706f899e124a2b340dc0529386bb2b235 Mon Sep 17 00:00:00 2001 From: Tvrtko Ursulin Date: Tue, 13 Dec 2016 14:37:27 +0000 Subject: [PATCH] drm/i915: Optimise VMA lookup slightly Cast VM pointers before substraction to save the compiler doing a smart one which includes multiplication. v2: Only keep the first optimisation and prettify it. (Chris Wilson) Signed-off-by: Tvrtko Ursulin Cc: Chris Wilson Reviewed-by: Chris Wilson Link: http://patchwork.freedesktop.org/patch/msgid/1481639847-9214-1-git-send-email-tvrtko.ursulin@linux.intel.com --- drivers/gpu/drm/i915/i915_vma.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h index 21be74c61065..e3b2b3b1e056 100644 --- a/drivers/gpu/drm/i915/i915_vma.h +++ b/drivers/gpu/drm/i915/i915_vma.h @@ -178,15 +178,23 @@ static inline void i915_vma_put(struct i915_vma *vma) i915_gem_object_put(vma->obj); } +static __always_inline ptrdiff_t ptrdiff(const void *a, const void *b) +{ + return a - b; +} + static inline long i915_vma_compare(struct i915_vma *vma, struct i915_address_space *vm, const struct i915_ggtt_view *view) { + ptrdiff_t cmp; + GEM_BUG_ON(view && !i915_is_ggtt(vm)); - if (vma->vm != vm) - return vma->vm - vm; + cmp = ptrdiff(vma->vm, vm); + if (cmp) + return cmp; if (!view) return vma->ggtt_view.type; -- 2.20.1