[PATCH 11/12] drm/vmwgfx: Remove usage of MOBFMT_RANGE

[Martin Krastev]

On Mon, 2021-12-06 at 12:26 -0500, Zack Rusin wrote:
> From: Zack Rusin <zackr at vmware.com>
> 
> Using MOBFMT_RANGE in the early days of guest backed objects was a major
> performance win but that has changed a lot since. There's no more
> a performance reason to use MOBFMT_RANGE. The device can/will still
> profit from the pages being contiguous but marking them as MOBFMT_RANGE
> no longer matters.
> Benchmarks (e.g. heaven, valley) show that creating page tables
> for mob memory is actually faster than using mobfmt ranges.
> 
> Signed-off-by: Zack Rusin <zackr at vmware.com>
> ---
>  drivers/gpu/drm/vmwgfx/vmwgfx_drv.h        |  1 -
>  drivers/gpu/drm/vmwgfx/vmwgfx_mob.c        |  6 ------
>  drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c | 12 ------------
>  3 files changed, 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
> index 21dd69e5cdfb..1760ba1b0d4a 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
> @@ -333,7 +333,6 @@ struct vmw_sg_table {
>  	struct page **pages;
>  	const dma_addr_t *addrs;
>  	struct sg_table *sgt;
> -	unsigned long num_regions;
>  	unsigned long num_pages;
>  };
>  
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_mob.c b/drivers/gpu/drm/vmwgfx/vmwgfx_mob.c
> index 65f7c2bdc322..2d91a44a3b22 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_mob.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_mob.c
> @@ -146,9 +146,6 @@ static int vmw_setup_otable_base(struct vmw_private *dev_priv,
>  	if (otable->size <= PAGE_SIZE) {
>  		mob->pt_level = VMW_MOBFMT_PTDEPTH_0;
>  		mob->pt_root_page = vmw_piter_dma_addr(&iter);
> -	} else if (vsgt->num_regions == 1) {
> -		mob->pt_level = SVGA3D_MOBFMT_RANGE;
> -		mob->pt_root_page = vmw_piter_dma_addr(&iter);
>  	} else {
>  		ret = vmw_mob_pt_populate(dev_priv, mob);
>  		if (unlikely(ret != 0))
> @@ -623,9 +620,6 @@ int vmw_mob_bind(struct vmw_private *dev_priv,
>  	if (likely(num_data_pages == 1)) {
>  		mob->pt_level = VMW_MOBFMT_PTDEPTH_0;
>  		mob->pt_root_page = vmw_piter_dma_addr(&data_iter);
> -	} else if (vsgt->num_regions == 1) {
> -		mob->pt_level = SVGA3D_MOBFMT_RANGE;
> -		mob->pt_root_page = vmw_piter_dma_addr(&data_iter);
>  	} else if (unlikely(mob->pt_bo == NULL)) {
>  		ret = vmw_mob_pt_populate(dev_priv, mob);
>  		if (unlikely(ret != 0))
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
> index 20f752ff6168..b84ecc6d6611 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
> @@ -288,8 +288,6 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt)
>  {
>  	struct vmw_private *dev_priv = vmw_tt->dev_priv;
>  	struct vmw_sg_table *vsgt = &vmw_tt->vsgt;
> -	struct vmw_piter iter;
> -	dma_addr_t old;
>  	int ret = 0;
>  
>  	if (vmw_tt->mapped)
> @@ -321,16 +319,6 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt)
>  		break;
>  	}
>  
> -	old = ~((dma_addr_t) 0);
> -	vmw_tt->vsgt.num_regions = 0;
> -	for (vmw_piter_start(&iter, vsgt, 0); vmw_piter_next(&iter);) {
> -		dma_addr_t cur = vmw_piter_dma_addr(&iter);
> -
> -		if (cur != old + PAGE_SIZE)
> -			vmw_tt->vsgt.num_regions++;
> -		old = cur;
> -	}
> -
>  	vmw_tt->mapped = true;
>  	return 0;
>  

Reviewed-by: Martin Krastev <krastevm at vmware.com>