memory hotplug: alloc page from other node in memory online

To initialize hotadded node, some pages are allocated.  At that time, the
node hasn't memory, this makes the allocation always fail.  In such case,
let's allocate pages from other nodes.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Yakui Zhao <yakui.zhao@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index f22b4eb..3d535d5 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -116,10 +116,16 @@
 		nid = page_to_nid(pfn_to_page(pfn));
 		table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
 		VM_BUG_ON(!slab_is_available());
-		base = kmalloc_node(table_size,
+		if (node_state(nid, N_HIGH_MEMORY)) {
+			base = kmalloc_node(table_size,
 				GFP_KERNEL | __GFP_NOWARN, nid);
-		if (!base)
-			base = vmalloc_node(table_size, nid);
+			if (!base)
+				base = vmalloc_node(table_size, nid);
+		} else {
+			base = kmalloc(table_size, GFP_KERNEL | __GFP_NOWARN);
+			if (!base)
+				base = vmalloc(table_size);
+		}
 	} else {
 		/*
  		 * We don't have to allocate page_cgroup again, but