drm/i915: cleanup cache-coloring

Try to tidy up the cache-coloring such that we rid the code of any
mm.color_adjust assumptions, this should hopefully make it more obvious
in the code when we need to actually use the cache-level as the color,
and as a bonus should make adding a different color-scheme simpler.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190909124052.22900-3-matthew.auld@intel.com

drivers/gpu/drm/i915/gem/i915_gem_domain.c

@@ -294,8 +294,10 @@ int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj,
 		}
 	}
 
-	list_for_each_entry(vma, &obj->vma.list, obj_link)
-		vma->node.color = cache_level;
+	list_for_each_entry(vma, &obj->vma.list, obj_link) {
+		if (i915_vm_has_cache_coloring(vma->vm))
+			vma->node.color = cache_level;
+	}
 	i915_gem_object_set_cache_coherency(obj, cache_level);
 	obj->cache_dirty = true; /* Always invalidate stale cachelines */
 

drivers/gpu/drm/i915/i915_drv.h

@@ -2364,7 +2364,7 @@ i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id)
 /* i915_gem_evict.c */
 int __must_check i915_gem_evict_something(struct i915_address_space *vm,
 					  u64 min_size, u64 alignment,
-					  unsigned cache_level,
+					  unsigned long color,
 					  u64 start, u64 end,
 					  unsigned flags);
 int __must_check i915_gem_evict_for_node(struct i915_address_space *vm,

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -70,7 +70,7 @@ mark_free(struct drm_mm_scan *scan,
  * @vm: address space to evict from
  * @min_size: size of the desired free space
  * @alignment: alignment constraint of the desired free space
- * @cache_level: cache_level for the desired space
+ * @color: color for the desired space
  * @start: start (inclusive) of the range from which to evict objects
  * @end: end (exclusive) of the range from which to evict objects
  * @flags: additional flags to control the eviction algorithm
@@ -91,7 +91,7 @@ mark_free(struct drm_mm_scan *scan,
 int
 i915_gem_evict_something(struct i915_address_space *vm,
 			 u64 min_size, u64 alignment,
-			 unsigned cache_level,
+			 unsigned long color,
 			 u64 start, u64 end,
 			 unsigned flags)
 {
@@ -124,7 +124,7 @@ i915_gem_evict_something(struct i915_address_space *vm,
 	if (flags & PIN_MAPPABLE)
 		mode = DRM_MM_INSERT_LOW;
 	drm_mm_scan_init_with_range(&scan, &vm->mm,
-				    min_size, alignment, cache_level,
+				    min_size, alignment, color,
 				    start, end, mode);
 
 	/*
@@ -266,7 +266,6 @@ int i915_gem_evict_for_node(struct i915_address_space *vm,
 	u64 start = target->start;
 	u64 end = start + target->size;
 	struct i915_vma *vma, *next;
-	bool check_color;
 	int ret = 0;
 
 	lockdep_assert_held(&vm->i915->drm.struct_mutex);
@@ -283,8 +282,7 @@ int i915_gem_evict_for_node(struct i915_address_space *vm,
 	if (!(flags & PIN_NONBLOCK))
 		i915_retire_requests(vm->i915);
 
-	check_color = vm->mm.color_adjust;
-	if (check_color) {
+	if (i915_vm_has_cache_coloring(vm)) {
 		/* Expand search to cover neighbouring guard pages (or lack!) */
 		if (start)
 			start -= I915_GTT_PAGE_SIZE;
@@ -310,7 +308,7 @@ int i915_gem_evict_for_node(struct i915_address_space *vm,
 		 * abutt and conflict. If they are in conflict, then we evict
 		 * those as well to make room for our guard pages.
 		 */
-		if (check_color) {
+		if (i915_vm_has_cache_coloring(vm)) {
 			if (node->start + node->size == target->start) {
 				if (node->color == target->color)
 					continue;

drivers/gpu/drm/i915/i915_gem_gtt.h

@@ -376,6 +376,12 @@ i915_vm_has_scratch_64K(struct i915_address_space *vm)
 	return vm->scratch_order == get_order(I915_GTT_PAGE_SIZE_64K);
 }
 
+static inline bool
+i915_vm_has_cache_coloring(struct i915_address_space *vm)
+{
+	return i915_is_ggtt(vm) && vm->mm.color_adjust;
+}
+
 /* The Graphics Translation Table is the way in which GEN hardware translates a
  * Graphics Virtual Address into a Physical Address. In addition to the normal
  * collateral associated with any va->pa translations GEN hardware also has a

drivers/gpu/drm/i915/i915_vma.c

@@ -477,7 +477,7 @@ void __i915_vma_set_map_and_fenceable(struct i915_vma *vma)
 		vma->flags &= ~I915_VMA_CAN_FENCE;
 }
 
-bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long cache_level)
+bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long color)
 {
 	struct drm_mm_node *node = &vma->node;
 	struct drm_mm_node *other;
@@ -489,7 +489,7 @@ bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long cache_level)
 	 * these constraints apply and set the drm_mm.color_adjust
 	 * appropriately.
 	 */
-	if (vma->vm->mm.color_adjust == NULL)
+	if (!i915_vm_has_cache_coloring(vma->vm))
 		return true;
 
 	/* Only valid to be called on an already inserted vma */
@@ -497,12 +497,12 @@ bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long cache_level)
 	GEM_BUG_ON(list_empty(&node->node_list));
 
 	other = list_prev_entry(node, node_list);
-	if (i915_node_color_differs(other, cache_level) &&
+	if (i915_node_color_differs(other, color) &&
 	    !drm_mm_hole_follows(other))
 		return false;
 
 	other = list_next_entry(node, node_list);
-	if (i915_node_color_differs(other, cache_level) &&
+	if (i915_node_color_differs(other, color) &&
 	    !drm_mm_hole_follows(node))
 		return false;
 
@@ -539,7 +539,7 @@ static int
 i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 {
 	struct drm_i915_private *dev_priv = vma->vm->i915;
-	unsigned int cache_level;
+	unsigned long color;
 	u64 start, end;
 	int ret;
 
@@ -580,14 +580,14 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 		return -ENOSPC;
 	}
 
+	color = 0;
 	if (vma->obj) {
 		ret = i915_gem_object_pin_pages(vma->obj);
 		if (ret)
 			return ret;
 
-		cache_level = vma->obj->cache_level;
-	} else {
-		cache_level = 0;
+		if (i915_vm_has_cache_coloring(vma->vm))
+			color = vma->obj->cache_level;
 	}
 
 	GEM_BUG_ON(vma->pages);
@@ -605,7 +605,7 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 		}
 
 		ret = i915_gem_gtt_reserve(vma->vm, &vma->node,
-					   size, offset, cache_level,
+					   size, offset, color,
 					   flags);
 		if (ret)
 			goto err_clear;
@@ -644,7 +644,7 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 		}
 
 		ret = i915_gem_gtt_insert(vma->vm, &vma->node,
-					  size, alignment, cache_level,
+					  size, alignment, color,
 					  start, end, flags);
 		if (ret)
 			goto err_clear;
@@ -653,7 +653,7 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 		GEM_BUG_ON(vma->node.start + vma->node.size > end);
 	}
 	GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
-	GEM_BUG_ON(!i915_gem_valid_gtt_space(vma, cache_level));
+	GEM_BUG_ON(!i915_gem_valid_gtt_space(vma, color));
 
 	mutex_lock(&vma->vm->mutex);
 	list_move_tail(&vma->vm_link, &vma->vm->bound_list);

drivers/gpu/drm/i915/i915_vma.h

@@ -295,7 +295,7 @@ i915_vma_compare(struct i915_vma *vma,
 
 int i915_vma_bind(struct i915_vma *vma, enum i915_cache_level cache_level,
 		  u32 flags);
-bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long cache_level);
+bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long color);
 bool i915_vma_misplaced(const struct i915_vma *vma,
 			u64 size, u64 alignment, u64 flags);
 void __i915_vma_set_map_and_fenceable(struct i915_vma *vma);

drivers/gpu/drm/i915/selftests/i915_gem_evict.c

@@ -274,12 +274,14 @@ static int igt_evict_for_cache_color(void *arg)
 	LIST_HEAD(objects);
 	int err;
 
-	/* Currently the use of color_adjust is limited to cache domains within
-	 * the ggtt, and so the presence of mm.color_adjust is assumed to be
-	 * i915_ggtt_color_adjust throughout our driver, so using a mock color
-	 * adjust will work just fine for our purposes.
+	/*
+	 * Currently the use of color_adjust for the GGTT is limited to cache
+	 * coloring and guard pages, and so the presence of mm.color_adjust for
+	 * the GGTT is assumed to be i915_ggtt_color_adjust, hence using a mock
+	 * color adjust will work just fine for our purposes.
 	 */
 	ggtt->vm.mm.color_adjust = mock_color_adjust;
+	GEM_BUG_ON(!i915_vm_has_cache_coloring(&ggtt->vm));
 
 	obj = i915_gem_object_create_internal(i915, I915_GTT_PAGE_SIZE);
 	if (IS_ERR(obj)) {