Instead of storing the number of memory nodes in each handle, we can use the

_starpu_get_memory_nodes_count() function.

src/datawizard/coherency.h

@@ -78,8 +78,6 @@ struct starpu_data_state_t {
 	/* protect meta data */
 	starpu_spinlock_t header_lock;
 
-	uint32_t nnodes; /* the number of memory nodes that may use it */
-
 	/* In case we user filters, the handle may describe a sub-data */
 	struct starpu_data_state_t *root_handle; /* root of the tree */
 	struct starpu_data_state_t *father_handle; /* father of the node, NULL if the current node is the root */

src/datawizard/interfaces/data_interface.c

@@ -33,9 +33,6 @@ static void _starpu_register_new_data(starpu_data_handle handle,
 	/* first take care to properly lock the data */
 	_starpu_spin_lock(&handle->header_lock);
 
-	/* we assume that all nodes may use that data */
-	handle->nnodes = STARPU_MAXNODES;
-
 	/* there is no hierarchy yet */
 	handle->nchildren = 0;
 	handle->root_handle = handle;