prepare for multiple node allocators - add an enum to label nodes

src/node.c

@@ -80,6 +80,7 @@ node_alloc(void)
 	// MPL zeroes
 	AZ(node->magic);
 	node->magic = NODE_MAGIC;
+	node->allocator = NA_MPL;
 	return (node);
 }
 
@@ -136,6 +137,7 @@ tree_free(struct req *req, struct node *node)
 		tree_prune(req, node);
 
 	node_fini(req, node);
+	assert(node->allocator == NA_MPL);
 	MPL_Free(mempool, node);
 }
 

src/node.h

@@ -174,11 +174,18 @@ struct node_final {
 	pthread_cond_t		fi_cond;
 };
 
+enum n_alloc {
+	NA_INVALID	= 0,
+	NA_WS,
+	NA_MPL
+} __attribute__ ((__packed__));
+
 struct node {
 	unsigned		magic;
 #define NODE_MAGIC 0xe31edef3
 	enum n_type		type;
 	enum n_state		state;
+	enum n_alloc		allocator;
 	VSTAILQ_ENTRY(node)	sibling;
 	VSTAILQ_ENTRY(node)	unpend;
 	struct node		*parent;