[PATCH] create node_online_map

From Matthew Dobson.

Create and use node_online_map.

This patch creates a node_online_map, much like cpu_online_map.  It
also creates the standard helper functions, ie: node_online(),
num_online_nodes(), node_set_online(), node_set_offline().

This is used by driverFS topology to keep track of which Nodes
are in the system and online.

arch/i386/kernel/numaq.c

@@ -52,6 +52,7 @@ static void __init smp_dump_qct(void)
 	numnodes = 0;
 	for(node = 0; node < MAX_NUMNODES; node++) {
 		if(scd->quads_present31_0 & (1 << node)) {
+			node_set_online(node);
 			numnodes++;
 			eq = &scd->eq[node];
 			/* Convert to pages */

arch/i386/mach-generic/topology.c

@@ -38,13 +38,11 @@ struct i386_cpu cpu_devices[NR_CPUS];
 struct i386_node node_devices[MAX_NUMNODES];
 struct i386_memblk memblk_devices[MAX_NR_MEMBLKS];
 
-extern int numnodes;
-
 static int __init topology_init(void)
 {
 	int i;
 
-	for (i = 0; i < numnodes; i++)
+	for (i = 0; i < num_online_nodes(); i++)
 		arch_register_node(i);
 	for (i = 0; i < NR_CPUS; i++)
 		if (cpu_possible(i)) arch_register_cpu(i);

include/linux/mmzone.h

@@ -280,10 +280,25 @@ extern struct pglist_data contig_page_data;
 #endif /* !CONFIG_DISCONTIGMEM */
 
 
+extern DECLARE_BITMAP(node_online_map, MAX_NUMNODES);
 extern DECLARE_BITMAP(memblk_online_map, MAX_NR_MEMBLKS);
 
 #if defined(CONFIG_DISCONTIGMEM) || defined(CONFIG_NUMA)
 
+#define node_online(node)	test_bit(node, node_online_map)
+#define node_set_online(node)	set_bit(node, node_online_map)
+#define node_set_offline(node)	clear_bit(node, node_online_map)
+static inline unsigned int num_online_nodes(void)
+{
+	int i, num = 0;
+
+	for(i = 0; i < MAX_NUMNODES; i++){
+		if (node_online(i))
+			num++;
+	}
+	return num;
+}
+
 #define memblk_online(memblk)		test_bit(memblk, memblk_online_map)
 #define memblk_set_online(memblk)	set_bit(memblk, memblk_online_map)
 #define memblk_set_offline(memblk)	clear_bit(memblk, memblk_online_map)
@@ -300,6 +315,14 @@ static inline unsigned int num_online_memblks(void)
 
 #else /* !CONFIG_DISCONTIGMEM && !CONFIG_NUMA */
 
+#define node_online(node) \
+	({ BUG_ON((node) != 0); test_bit(node, node_online_map); })
+#define node_set_online(node) \
+	({ BUG_ON((node) != 0); set_bit(node, node_online_map); })
+#define node_set_offline(node) \
+	({ BUG_ON((node) != 0); clear_bit(node, node_online_map); })
+#define num_online_nodes()	1
+
 #define memblk_online(memblk) \
 	({ BUG_ON((memblk) != 0); test_bit(memblk, memblk_online_map); })
 #define memblk_set_online(memblk) \

mm/page_alloc.c

@@ -31,6 +31,7 @@
 
 #include <asm/topology.h>
 
+DECLARE_BITMAP(node_online_map, MAX_NUMNODES);
 DECLARE_BITMAP(memblk_online_map, MAX_NR_MEMBLKS);
 struct pglist_data *pgdat_list;
 unsigned long totalram_pages;