drm/vmwgfx: Use an RBtree instead of linked list for MOB resources

With emulated coherent memory we need to be able to quickly look up
a resource from the MOB offset. Instead of traversing a linked list with
O(n) worst case, use an RBtree with O(log n) worst case complexity.

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

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
index 90ca866640fe5c6a852c39693ef886abbb35b771..e8bc7a7ac0311be5ebf0977464b2ddc0d825eb78 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
@@ -464,6 +464,7 @@ void vmw_bo_bo_free(struct ttm_buffer_object *bo)
        struct vmw_buffer_object *vmw_bo = vmw_buffer_object(bo);
 
        WARN_ON(vmw_bo->dirty);
+       WARN_ON(!RB_EMPTY_ROOT(&vmw_bo->res_tree));
        vmw_bo_unmap(vmw_bo);
        kfree(vmw_bo);
 }
@@ -480,6 +481,7 @@ static void vmw_user_bo_destroy(struct ttm_buffer_object *bo)
        struct vmw_buffer_object *vbo = &vmw_user_bo->vbo;
 
        WARN_ON(vbo->dirty);
+       WARN_ON(!RB_EMPTY_ROOT(&vbo->res_tree));
        vmw_bo_unmap(vbo);
        ttm_prime_object_kfree(vmw_user_bo, prime);
 }
@@ -515,8 +517,7 @@ int vmw_bo_init(struct vmw_private *dev_priv,
        memset(vmw_bo, 0, sizeof(*vmw_bo));
        BUILD_BUG_ON(TTM_MAX_BO_PRIORITY <= 3);
        vmw_bo->base.priority = 3;
-
-       INIT_LIST_HEAD(&vmw_bo->res_list);
+       vmw_bo->res_tree = RB_ROOT;
 
        ret = ttm_bo_init(bdev, &vmw_bo->base, size,
                          ttm_bo_type_device, placement,

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 27c2593957909cb0d9a7fb4d5f40b15134f4b7c0..9b347923196f330515eb324e93762552fca75b55 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -89,7 +89,7 @@ struct vmw_fpriv {
 /**
  * struct vmw_buffer_object - TTM buffer object with vmwgfx additions
  * @base: The TTM buffer object
- * @res_list: List of resources using this buffer object as a backing MOB
+ * @res_tree: RB tree of resources using this buffer object as a backing MOB
  * @pin_count: pin depth
  * @dx_query_ctx: DX context if this buffer object is used as a DX query MOB
  * @map: Kmap object for semi-persistent mappings
@@ -98,7 +98,7 @@ struct vmw_fpriv {
  */
 struct vmw_buffer_object {
        struct ttm_buffer_object base;
-       struct list_head res_list;
+       struct rb_root res_tree;
        s32 pin_count;
        /* Not ref-counted.  Protected by binding_mutex */
        struct vmw_resource *dx_query_ctx;
@@ -146,8 +146,8 @@ struct vmw_res_func;
  * pin-count greater than zero. It is not on the resource LRU lists and its
  * backup buffer is pinned. Hence it can't be evicted.
  * @func: Method vtable for this resource. Immutable.
+ * @mob_node; Node for the MOB backup rbtree. Protected by @backup reserved.
  * @lru_head: List head for the LRU list. Protected by @dev_priv::resource_lock.
- * @mob_head: List head for the MOB backup list. Protected by @backup reserved.
  * @binding_head: List head for the context binding list. Protected by
  * the @dev_priv::binding_mutex
  * @res_free: The resource destructor.
@@ -168,8 +168,8 @@ struct vmw_resource {
        unsigned long backup_offset;
        unsigned long pin_count;
        const struct vmw_res_func *func;
+       struct rb_node mob_node;
        struct list_head lru_head;
-       struct list_head mob_head;
        struct list_head binding_head;
        struct vmw_resource_dirty *dirty;
        void (*res_free) (struct vmw_resource *res);
@@ -742,7 +742,7 @@ void vmw_resource_dirty_update(struct vmw_resource *res, pgoff_t start,
  */
 static inline bool vmw_resource_mob_attached(const struct vmw_resource *res)
 {
-       return !list_empty(&res->mob_head);
+       return !RB_EMPTY_NODE(&res->mob_node);
 }
 
 /**

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
index da9afa83fb4f6e9a60fd5e1359dbad095799f87f..b84dd5953886bc587632ddfc11d0c09c74da0615 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
@@ -41,11 +41,24 @@
 void vmw_resource_mob_attach(struct vmw_resource *res)
 {
        struct vmw_buffer_object *backup = res->backup;
+       struct rb_node **new = &backup->res_tree.rb_node, *parent = NULL;
 
        lockdep_assert_held(&backup->base.resv->lock.base);
        res->used_prio = (res->res_dirty) ? res->func->dirty_prio :
                res->func->prio;
-       list_add_tail(&res->mob_head, &backup->res_list);
+
+       while (*new) {
+               struct vmw_resource *this =
+                       container_of(*new, struct vmw_resource, mob_node);
+
+               parent = *new;
+               new = (res->backup_offset < this->backup_offset) ?
+                       &((*new)->rb_left) : &((*new)->rb_right);
+       }
+
+       rb_link_node(&res->mob_node, parent, new);
+       rb_insert_color(&res->mob_node, &backup->res_tree);
+
        vmw_bo_prio_add(backup, res->used_prio);
 }
 
@@ -59,7 +72,8 @@ void vmw_resource_mob_detach(struct vmw_resource *res)
 
        lockdep_assert_held(&backup->base.resv->lock.base);
        if (vmw_resource_mob_attached(res)) {
-               list_del_init(&res->mob_head);
+               rb_erase(&res->mob_node, &backup->res_tree);
+               RB_CLEAR_NODE(&res->mob_node);
                vmw_bo_prio_del(backup, res->used_prio);
        }
 }
@@ -206,8 +220,8 @@ int vmw_resource_init(struct vmw_private *dev_priv, struct vmw_resource *res,
        res->res_free = res_free;
        res->dev_priv = dev_priv;
        res->func = func;
+       RB_CLEAR_NODE(&res->mob_node);
        INIT_LIST_HEAD(&res->lru_head);
-       INIT_LIST_HEAD(&res->mob_head);
        INIT_LIST_HEAD(&res->binding_head);
        res->id = -1;
        res->backup = NULL;
@@ -756,19 +770,20 @@ out_no_validate:
  */
 void vmw_resource_unbind_list(struct vmw_buffer_object *vbo)
 {
-
-       struct vmw_resource *res, *next;
        struct ttm_validate_buffer val_buf = {
                .bo = &vbo->base,
                .num_shared = 0
        };
 
        lockdep_assert_held(&vbo->base.resv->lock.base);
-       list_for_each_entry_safe(res, next, &vbo->res_list, mob_head) {
-               if (!res->func->unbind)
-                       continue;
+       while (!RB_EMPTY_ROOT(&vbo->res_tree)) {
+               struct rb_node *node = vbo->res_tree.rb_node;
+               struct vmw_resource *res =
+                       container_of(node, struct vmw_resource, mob_node);
+
+               if (!WARN_ON_ONCE(!res->func->unbind))
+                       (void) res->func->unbind(res, res->res_dirty, &val_buf);
 
-               (void) res->func->unbind(res, res->res_dirty, &val_buf);
                res->backup_dirty = true;
                res->res_dirty = false;
                vmw_resource_mob_detach(res);