diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 3e16fe0..e759109 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -463,19 +463,6 @@
 
 #ifdef CONFIG_MEMORY_HOTPLUG
 /*
- * XXX: memory_add_physaddr_to_nid() is to find node id from physical address
- *	via probe interface of sysfs. If acpi notifies hot-add event, then it
- *	can tell node id by searching dsdt. But, probe interface doesn't have
- *	node id. So, return 0 as node id at this time.
- */
-#ifdef CONFIG_NUMA
-int memory_add_physaddr_to_nid(u64 start)
-{
-	return 0;
-}
-#endif
-
-/*
  * Memory is added always to NORMAL zone. This means you will never get
  * additional DMA/DMA32 memory.
  */
@@ -506,6 +493,13 @@
 }
 EXPORT_SYMBOL_GPL(remove_memory);
 
+#ifndef CONFIG_ACPI_NUMA
+int memory_add_physaddr_to_nid(u64 start)
+{
+	return 0;
+}
+#endif
+
 #else /* CONFIG_MEMORY_HOTPLUG */
 /*
  * Memory Hotadd without sparsemem. The mem_maps have been allocated in advance,