[Mesa-dev] [PATCH 04/14] gallium/radeon: add RADEON_FLAG_HANDLE

[Marek Olšák]

On Tue, Sep 13, 2016 at 11:56 AM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>
> When passed to winsys->buffer_create, this flag will indicate that we require
> a buffer that maps 1:1 with a kernel buffer handle.
>
> This is currently set for all textures, since textures can potentially be
> exported to other processes. This is not a huge loss, since the main purpose
> of this patch series is to deal with applications that allocate many small
> buffers.
>
> A hypothetical application with tons of tiny textures might still benefit
> from not setting this flag, but that's not a use case I'm worried about
> just now.
> ---
>  src/gallium/drivers/r300/r300_texture.c       | 2 +-
>  src/gallium/drivers/radeon/r600_texture.c     | 2 ++
>  src/gallium/drivers/radeon/radeon_winsys.h    | 1 +
>  src/gallium/winsys/amdgpu/drm/amdgpu_bo.c     | 3 +++
>  src/gallium/winsys/radeon/drm/radeon_drm_bo.c | 3 +++
>  src/gallium/winsys/radeon/drm/radeon_drm_cs.c | 2 +-
>  6 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/src/gallium/drivers/r300/r300_texture.c b/src/gallium/drivers/r300/r300_texture.c
> index 5f459e4..fbac07a 100644
> --- a/src/gallium/drivers/r300/r300_texture.c
> +++ b/src/gallium/drivers/r300/r300_texture.c
> @@ -1107,21 +1107,21 @@ r300_texture_create_object(struct r300_screen *rscreen,
>          tex->domain &= ~RADEON_DOMAIN_GTT;
>      }
>      /* Just fail if the texture is too large. */
>      if (!tex->domain) {
>          goto fail;
>      }
>
>      /* Create the backing buffer if needed. */
>      if (!tex->buf) {
>          tex->buf = rws->buffer_create(rws, tex->tex.size_in_bytes, 2048,
> -                                      tex->domain, 0);
> +                                      tex->domain, RADEON_FLAG_HANDLE);
>
>          if (!tex->buf) {
>              goto fail;
>          }
>      }
>
>      if (SCREEN_DBG_ON(rscreen, DBG_MSAA) && base->nr_samples > 1) {
>          fprintf(stderr, "r300: %ix MSAA %s buffer created\n",
>                  base->nr_samples,
>                  util_format_is_depth_or_stencil(base->format) ? "depth" : "color");
> diff --git a/src/gallium/drivers/radeon/r600_texture.c b/src/gallium/drivers/radeon/r600_texture.c
> index 41fd94b..b6e5880 100644
> --- a/src/gallium/drivers/radeon/r600_texture.c
> +++ b/src/gallium/drivers/radeon/r600_texture.c
> @@ -1105,20 +1105,22 @@ r600_texture_create_object(struct pipe_screen *screen,
>                         rtex->dcc_offset = align64(rtex->size, rtex->surface.dcc_alignment);
>                         rtex->size = rtex->dcc_offset + rtex->surface.dcc_size;
>                 }
>         }
>
>         /* Now create the backing buffer. */
>         if (!buf) {
>                 r600_init_resource_fields(rscreen, resource, rtex->size,
>                                           rtex->surface.bo_alignment);
>
> +               resource->flags |= RADEON_FLAG_HANDLE;
> +
>                 if (!r600_alloc_resource(rscreen, resource)) {
>                         FREE(rtex);
>                         return NULL;
>                 }
>         } else {
>                 resource->buf = buf;
>                 resource->gpu_address = rscreen->ws->buffer_get_virtual_address(resource->buf);
>                 resource->domains = rscreen->ws->buffer_get_initial_domain(resource->buf);
>         }
>
> diff --git a/src/gallium/drivers/radeon/radeon_winsys.h b/src/gallium/drivers/radeon/radeon_winsys.h
> index 809a203..8196358 100644
> --- a/src/gallium/drivers/radeon/radeon_winsys.h
> +++ b/src/gallium/drivers/radeon/radeon_winsys.h
> @@ -45,20 +45,21 @@ enum radeon_bo_layout {
>  enum radeon_bo_domain { /* bitfield */
>      RADEON_DOMAIN_GTT  = 2,
>      RADEON_DOMAIN_VRAM = 4,
>      RADEON_DOMAIN_VRAM_GTT = RADEON_DOMAIN_VRAM | RADEON_DOMAIN_GTT
>  };
>
>  enum radeon_bo_flag { /* bitfield */
>      RADEON_FLAG_GTT_WC =        (1 << 0),
>      RADEON_FLAG_CPU_ACCESS =    (1 << 1),
>      RADEON_FLAG_NO_CPU_ACCESS = (1 << 2),
> +    RADEON_FLAG_HANDLE =        (1 << 3), /* whether get_handle must be supported */

But get_handle must always be supported because of inter-API interop.
Maybe the comment should be:
   /* get_handle must return offset=0 */

Or even:
   /* the buffer must not be suballocated */

Marek