Re: [PATCH 70/73] drm/i915: Move obj->active:5 to obj->flags

[Joonas Lahtinen <joonas.lahtinen@linux.intel.com>]

On ma, 2016-08-01 at 10:11 +0100, Chris Wilson wrote:
> We are motivated to avoid using a bitfield for obj->active for a couple
> of reasons. Firstly, we wish to document our lockless read of obj->active
> using READ_ONCE inside i915_gem_busy_ioctl() and that requires an
> integral type (i.e. not a bitfield). Secondly, gcc produces abysmal code
> when presented with a bitfield and that shows up high on the profiles of
> request tracking (mainly due to excess memory traffic as it converts
> the bitfield to a register and back and generates frequent AGI in the
> process).
> 
> v2: BIT, break up a long line in compute the other engines, new paint
> for i915_gem_object_is_active (now i915_gem_object_get_active).
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Patch reads much better now,

Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

Regards, Joonas
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation
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