[Mesa-dev] [PATCH] gallium: new transfer flag: DISCARD_WHOLE_RESOURCE

[José Fonseca]

A bit more background about this: this flag allows to get discard from
the app down to the kernel, where most memory managers are able to do
discard while mapping level without the whole map-non-block +
create/destroy resource roundtrip.  This is Keith's idea.

Jose


On Fri, 2011-02-18 at 08:15 -0800, jfonseca at vmware.com wrote:
> From: Keith Whitwell <keithw at vmware.com>
> 
> ---
>  src/gallium/include/pipe/p_defines.h |   19 +++++++++++++++++--
>  1 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
> index f66bbaf..2de707f 100644
> --- a/src/gallium/include/pipe/p_defines.h
> +++ b/src/gallium/include/pipe/p_defines.h
> @@ -229,9 +229,9 @@ enum pipe_transfer_usage {
>      *
>      * See also:
>      * - OpenGL's ARB_map_buffer_range extension, MAP_INVALIDATE_RANGE_BIT flag.
> -    * - Direct3D's D3DLOCK_DISCARD flag.
>      */
>     PIPE_TRANSFER_DISCARD = (1 << 8),
> +   PIPE_TRANSFER_DISCARD_RANGE = (1 << 8),
>  
>     /**
>      * Fail if the resource cannot be mapped immediately.
> @@ -266,7 +266,22 @@ enum pipe_transfer_usage {
>      * - pipe_context::transfer_flush_region
>      * - OpenGL's ARB_map_buffer_range extension, MAP_FLUSH_EXPLICIT_BIT flag.
>      */
> -   PIPE_TRANSFER_FLUSH_EXPLICIT = (1 << 11)
> +   PIPE_TRANSFER_FLUSH_EXPLICIT = (1 << 11),
> +
> +   /**
> +    * Discards all memory backing the resource.
> +    *
> +    * It should not be used with PIPE_TRANSFER_CPU_READ.
> +    *
> +    * This is equivalent to:
> +    * - OpenGL's ARB_map_buffer_range extension, MAP_INVALIDATE_BUFFER_BIT
> +    * - BufferData(NULL) on a GL buffer
> +    * - Direct3D's D3DLOCK_DISCARD flag.
> +    * - WDDM's D3DDDICB_LOCKFLAGS.Discard flag.
> +    * - D3D10 DDI's D3D10_DDI_MAP_WRITE_DISCARD flag
> +    * - D3D10's D3D10_MAP_WRITE_DISCARD flag.
> +    */
> +   PIPE_TRANSFER_DISCARD_WHOLE_RESOURCE = (1 << 12)
>  
>  };
>