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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2017-05-17 13:09:58 +0100 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2017-05-17 13:38:03 +0100 |
| commit | 991bfc64db096cb924d5d216a9cb469590f00428 (patch) | |
| tree | 834142f298410b00759f48197da53982b57ae467 | |
| parent | 47624cc3301b6033d51b84a1381c2d69fda9b1a0 (diff) | |
| download | linux-991bfc64db096cb924d5d216a9cb469590f00428.tar.bz2 | |
drm/i915: Make ptr_unpack_bits() more function-like
ptr_unpack_bits() is a function-like macro, as such it is meant to be
replaceable by a function. In this case, we should be passing in the
out-param as a pointer.
Bizarrely this does affect code generation:
function old new delta
i915_gem_object_pin_map 409 389 -20
An improvement(?) in this case, but one can't help wonder what
strict-aliasing optimisations we are preventing.
The generated code looks identical in using ptr_unpack_bits (no extra
motions to stack, the pointer and bits appear to be kept in registers),
the difference appears to be code ordering and with a reorder it is able
to use smaller forward jumps.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170517121007.27224-3-chris@chris-wilson.co.uk
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem.c | 2 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_utils.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index f9c6b9b5002c..5d68bece2ac3 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2612,7 +2612,7 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj, } GEM_BUG_ON(!obj->mm.pages); - ptr = ptr_unpack_bits(obj->mm.mapping, has_type); + ptr = ptr_unpack_bits(obj->mm.mapping, &has_type); if (ptr && has_type != type) { if (pinned) { ret = -EBUSY; diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h index f9d6607ef52f..18630d8f4be8 100644 --- a/drivers/gpu/drm/i915/i915_utils.h +++ b/drivers/gpu/drm/i915/i915_utils.h @@ -77,7 +77,7 @@ #define ptr_unpack_bits(ptr, bits) ({ \ unsigned long __v = (unsigned long)(ptr); \ - (bits) = __v & ~PAGE_MASK; \ + *(bits) = __v & ~PAGE_MASK; \ (typeof(ptr))(__v & PAGE_MASK); \ }) |