drm/vmwgfx: Remove usage of MOBFMT_RANGE

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@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211206172620.3139754-12-zack@kde.org

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;
 };
 

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))

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;