permit to online CPUs before local memory comes online

Commit Message

minskey April 27, 2010, 4:57 a.m. UTC

None

Patch

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 35b07b7..864035f 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -202,6 +202,7 @@  static inline int is_mem_section_removable(unsigned long pfn,
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
+extern int mem_online_node(int nid);
 extern int add_memory(int nid, u64 start, u64 size);
 extern int arch_add_memory(int nid, u64 start, u64 size);
 extern int remove_memory(u64 start, u64 size);
diff --git a/kernel/cpu.c b/kernel/cpu.c
index f8cced2..c31b9cb 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -335,6 +335,12 @@  out_notify:
 int __cpuinit cpu_up(unsigned int cpu)
 {
 	int err = 0;
+
+#ifdef	CONFIG_MEMORY_HOTPLUG
+	int nid;
+	pg_data_t	*pgdat;
+#endif
+
 	if (!cpu_possible(cpu)) {
 		printk(KERN_ERR "can't online cpu %d because it is not "
 			"configured as may-hotadd at boot time\n", cpu);
@@ -345,6 +351,26 @@  int __cpuinit cpu_up(unsigned int cpu)
 		return -EINVAL;
 	}
 
+#ifdef	CONFIG_MEMORY_HOTPLUG
+	nid = cpu_to_node(cpu);
+	if (!node_online(nid)) {
+		err = mem_online_node(nid);
+		if (err)
+			return err;
+	}
+
+	pgdat = NODE_DATA(nid);
+	if (!pgdat) {
+		printk(KERN_ERR
+			"Can't online cpu %d due to NULL pgdat\n", cpu);
+		return -ENOMEM;
+	}
+
+	if (pgdat->node_zonelists->_zonerefs->zone == NULL) {
+		build_all_zonelists();
+	} 
+#endif
+
 	cpu_maps_update_begin();
 
 	if (cpu_hotplug_disabled) {
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index be211a5..2d24bef 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -482,6 +482,31 @@  static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
 }
 
 
+/*
+ * called by cpu_up() to online a node without onlined memory.
+ */
+int mem_online_node(int nid)
+{
+	pg_data_t	*pgdat;
+	int	ret;
+
+	lock_system_sleep();
+	pgdat = hotadd_new_pgdat(nid, 0);
+	if (pgdat) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	node_set_online(nid);
+	ret = register_one_node(nid);
+	BUG_ON(ret);
+
+out:
+	unlock_system_sleep();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mem_online_node);
+
+
 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
 int __ref add_memory(int nid, u64 start, u64 size)
 {