drm/vmwgfx: Be more restrictive when dirtying resources

Currently we flag resources as dirty (GPU contents not yet read back to
the backing MOB) whenever they have been part of a command stream.
Obviously many resources can't be dirty and others can only be dirty when
written to by the GPU. That is when they are either bound to the context as
render-targets, depth-stencil, copy / clear destinations and
stream-output targets, or similarly when there are corresponding views into
them.
So mark resources dirty only in these special cases. Context- and cotable
resources are always marked dirty when referenced.
This is important for upcoming emulated coherent memory, since we can avoid
issuing automatic readbacks to non-dirty resources when the CPU tries to
access part of the backing MOB.

Testing: Unigine Heaven with max GPU memory set to 256MB resulting in
heavy resource thrashing.
---
v2: Addressed review comments by Deepak Rawat.
v3: Added some documentation

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Deepak Rawat <drawat@vmware.com>

1 files changed, 49 insertions, 9 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c b/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c
index e9944ac2e057..5ab7da1cbb45 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c
@@ -76,6 +76,8 @@ struct vmw_validation_res_node {
 	u32 switching_backup : 1;
 	u32 first_usage : 1;
 	u32 reserved : 1;
+	u32 dirty : 1;
+	u32 dirty_set : 1;
 	unsigned long private[0];
 };
 
@@ -299,6 +301,7 @@ int vmw_validation_add_bo(struct vmw_validation_context *ctx,
  * @ctx: The validation context.
  * @res: The resource.
  * @priv_size: Size of private, additional metadata.
+ * @dirty: Whether to change dirty status.
  * @p_node: Output pointer of additional metadata address.
  * @first_usage: Whether this was the first time this resource was seen.
  *
@@ -307,6 +310,7 @@ int vmw_validation_add_bo(struct vmw_validation_context *ctx,
 int vmw_validation_add_resource(struct vmw_validation_context *ctx,
 				struct vmw_resource *res,
 				size_t priv_size,
+				u32 dirty,
 				void **p_node,
 				bool *first_usage)
 {
@@ -358,6 +362,11 @@ int vmw_validation_add_resource(struct vmw_validation_context *ctx,
 	}
 
 out_fill:
+	if (dirty) {
+		node->dirty_set = 1;
+		/* Overwriting previous information here is intentional! */
+		node->dirty = (dirty & VMW_RES_DIRTY_SET) ? 1 : 0;
+	}
 	if (first_usage)
 		*first_usage = node->first_usage;
 	if (p_node)
@@ -367,6 +376,29 @@ out_fill:
 }
 
 /**
+ * vmw_validation_res_set_dirty - Register a resource dirty set or clear during
+ * validation.
+ * @ctx: The validation context.
+ * @val_private: The additional meta-data pointer returned when the
+ * resource was registered with the validation context. Used to identify
+ * the resource.
+ * @dirty: Dirty information VMW_RES_DIRTY_XX
+ */
+void vmw_validation_res_set_dirty(struct vmw_validation_context *ctx,
+				  void *val_private, u32 dirty)
+{
+	struct vmw_validation_res_node *val;
+
+	if (!dirty)
+		return;
+
+	val = container_of(val_private, typeof(*val), private);
+	val->dirty_set = 1;
+	/* Overwriting previous information here is intentional! */
+	val->dirty = (dirty & VMW_RES_DIRTY_SET) ? 1 : 0;
+}
+
+/**
  * vmw_validation_res_switch_backup - Register a backup MOB switch during
  * validation.
  * @ctx: The validation context.
@@ -450,15 +482,23 @@ void vmw_validation_res_unreserve(struct vmw_validation_context *ctx,
 	struct vmw_validation_res_node *val;
 
 	list_splice_init(&ctx->resource_ctx_list, &ctx->resource_list);
-
-	list_for_each_entry(val, &ctx->resource_list, head) {
-		if (val->reserved)
-			vmw_resource_unreserve(val->res,
-					       !backoff &&
-					       val->switching_backup,
-					       val->new_backup,
-					       val->new_backup_offset);
-	}
+	if (backoff)
+		list_for_each_entry(val, &ctx->resource_list, head) {
+			if (val->reserved)
+				vmw_resource_unreserve(val->res,
+						       false, false, false,
+						       NULL, 0);
+		}
+	else
+		list_for_each_entry(val, &ctx->resource_list, head) {
+			if (val->reserved)
+				vmw_resource_unreserve(val->res,
+						       val->dirty_set,
+						       val->dirty,
+						       val->switching_backup,
+						       val->new_backup,
+						       val->new_backup_offset);
+		}
 }
 
 /**