[Mesa-dev] [PATCH 1/4] radeonsi: use CE suballocator for CP DMA realignment.

[Nicolai Hähnle]

On 19.04.2016 17:50, Bas Nieuwenhuizen wrote:
> Use the CE suballocator instead of the normal one as the usage
> is most similar to the CE, i.e. only read and written on GPU
> and not mapped to CPU.

The scratch buffer is also only read and written by the GPU...

>
> Signed-off-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> ---
>   src/gallium/drivers/radeonsi/si_cp_dma.c | 27 ++++++++++-----------------
>   1 file changed, 10 insertions(+), 17 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_cp_dma.c b/src/gallium/drivers/radeonsi/si_cp_dma.c
> index 38e0ee6..264789d 100644
> --- a/src/gallium/drivers/radeonsi/si_cp_dma.c
> +++ b/src/gallium/drivers/radeonsi/si_cp_dma.c
> @@ -222,31 +222,24 @@ static void si_clear_buffer(struct pipe_context *ctx, struct pipe_resource *dst,
>    */
>   static void si_cp_dma_realign_engine(struct si_context *sctx, unsigned size)
>   {
> +
>   	uint64_t va;
>   	unsigned dma_flags = 0;
>   	unsigned scratch_size = CP_DMA_ALIGNMENT * 2;
> +	unsigned offset;
> +	struct r600_resource *tmp_buf;
>
>   	assert(size < CP_DMA_ALIGNMENT);
>
> -	/* Use the scratch buffer as the dummy buffer. The 3D engine should be
> -	 * idle at this point.
> -	 */
> -	if (!sctx->scratch_buffer ||
> -	    sctx->scratch_buffer->b.b.width0 < scratch_size) {
> -		r600_resource_reference(&sctx->scratch_buffer, NULL);
> -		sctx->scratch_buffer =
> -			si_resource_create_custom(&sctx->screen->b.b,
> -						  PIPE_USAGE_DEFAULT,
> -						  scratch_size);
> -		if (!sctx->scratch_buffer)
> -			return;
> -		sctx->emit_scratch_reloc = true;
> -	}
> +	u_suballocator_alloc(sctx->ce_suballocator, scratch_size, &offset,
> +	                     (struct pipe_resource**)&tmp_buf);
> +	if (!tmp_buf)
> +		return;
>
> -	si_cp_dma_prepare(sctx, &sctx->scratch_buffer->b.b,
> -			  &sctx->scratch_buffer->b.b, size, size, &dma_flags);
> +	si_cp_dma_prepare(sctx, &tmp_buf->b.b,
> +			  &tmp_buf->b.b, size, size, &dma_flags);
>
> -	va = sctx->scratch_buffer->gpu_address;
> +	va = tmp_buf->gpu_address + offset;
>   	si_emit_cp_dma_copy_buffer(sctx, va, va + CP_DMA_ALIGNMENT, size,
>   				   dma_flags);
>   }
>