[PATCH 2/2] drm/radeon: Use two-ended allocation by size

[Alex Deucher]

On Wed, Apr 2, 2014 at 1:04 PM, Lauri Kasanen <cand at gmx.com> wrote:
> This decreases eviction by up to 20%, by improving the fragmentation
> quality. No harm in normal cases that fit VRAM fully (PTS gaming suite).
>
> In some cases, even the VRAM-fitting cases improved slightly (openarena, urban terror).
>
> 512kb was measured as the most optimal threshold for 3d workloads common to radeon.
> Other drivers may need different thresholds according to their workloads.
>
> Signed-off-by: Lauri Kasanen <cand at gmx.com>
> ---
>  drivers/gpu/drm/radeon/radeon_object.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
> index 1375ff8..6251456 100644
> --- a/drivers/gpu/drm/radeon/radeon_object.c
> +++ b/drivers/gpu/drm/radeon/radeon_object.c
> @@ -104,7 +104,7 @@ bool radeon_ttm_bo_is_radeon_bo(struct ttm_buffer_object *bo)
>
>  void radeon_ttm_placement_from_domain(struct radeon_bo *rbo, u32 domain)
>  {
> -       u32 c = 0;
> +       u32 c = 0, i;
>
>         rbo->placement.fpfn = 0;
>         rbo->placement.lpfn = 0;
> @@ -131,6 +131,15 @@ void radeon_ttm_placement_from_domain(struct radeon_bo *rbo, u32 domain)
>                 rbo->placements[c++] = TTM_PL_MASK_CACHING | TTM_PL_FLAG_SYSTEM;
>         rbo->placement.num_placement = c;
>         rbo->placement.num_busy_placement = c;
> +
> +       /*
> +        * Use two-ended allocation depending on the buffer size to
> +        * improve fragmentation quality.
> +        * 512kb was measured as the most optimal number.
> +        */
> +       if (rbo->tbo.mem.size > 512 * 1024) for (i = 0; i < c; i++) {
> +               rbo->placements[i] |= TTM_PL_FLAG_TOPDOWN;
> +       }

Can you clean up the formatting of this chunk of code?  It's a bit
weird to read.

Alex

>  }
>
>  int radeon_bo_create(struct radeon_device *rdev,
> --
> 1.8.3.1
>
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