On Fri, 18 Jan 2008, Christoph Lameter wrote:

Memoryless nodes: Set N_NORMAL_MEMORY for a node if we do not support HIGHMEM

If !CONFIG_HIGHMEM then

enum node_states {
#ifdef CONFIG_HIGHMEM
        N_HIGH_MEMORY,          /* The node has regular or high memory */
#else
        N_HIGH_MEMORY = N_NORMAL_MEMORY,
#endif

So
	for_each_online_node(nid) {
                pg_data_t *pgdat = NODE_DATA(nid);
                free_area_init_node(nid, pgdat, NULL,
                                find_min_pfn_for_node(nid), NULL);

                /* Any memory on that node */
                if (pgdat->node_present_pages)
                        node_set_state(nid, N_HIGH_MEMORY);
			^^^ sets N_NORMAL_MEMORY      
          	check_for_regular_memory(pgdat);
        }