[PATCH] drm/radeon: Use two-ended allocation by size, v2

[Christian König]

Am 02.04.2014 19:33, schrieb Lauri Kasanen:
> 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.
>
> v2: Nicer formatting
> Signed-off-by: Lauri Kasanen <cand at gmx.com>

Reviewed-by: Christian König <christian.koenig at amd.com>

> ---
>   drivers/gpu/drm/radeon/radeon_object.c | 13 ++++++++++++-
>   1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
> index 1375ff8..19bec0d 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 +131,17 @@ 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;
> +		}
> +	}
>   }
>   
>   int radeon_bo_create(struct radeon_device *rdev,