[PATCH] x86_64: Support memory hotadd without sparsemem

Memory hotadd doesn't need SPARSEMEM, but can be handled by just preallocating
mem_maps. This only needs some untangling of ifdefs to enable the necessary
code even without SPARSEMEM.

Originally from Keith Mannthey, hacked by AK.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/mm/init.c

@@ -651,6 +651,7 @@ void __init mem_init(void)
  * Specifically, in the case of x86, we will always add
  * memory to the highmem for now.
  */
+#ifdef CONFIG_HOTPLUG_MEMORY
 #ifndef CONFIG_NEED_MULTIPLE_NODES
 int add_memory(u64 start, u64 size)
 {
@@ -667,6 +668,7 @@ int remove_memory(u64 start, u64 size)
 	return -EINVAL;
 }
 #endif
+#endif
 
 kmem_cache_t *pgd_cache;
 kmem_cache_t *pmd_cache;