hugetlb: use only nodes with memory for huge pages

Register per node hstate sysfs attributes only for nodes with memory.
Global replacement of 'all online nodes" with "all nodes with memory" in
mm/hugetlb.c.  Suggested by David Rientjes.

A subsequent patch will handle adding/removing of per node hstate sysfs
attributes when nodes transition to/from memoryless state via memory
hotplug.

NOTE: this patch has not been tested with memoryless nodes.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Reviewed-by: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Eric Whitney <eric.whitney@hp.com>
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/hugetlb.c b/mm/hugetlb.c
index 544f7bc..b4a2635 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -942,14 +942,14 @@
 
 	/*
 	 * We want to release as many surplus pages as possible, spread
-	 * evenly across all nodes. Iterate across all nodes until we
-	 * can no longer free unreserved surplus pages. This occurs when
-	 * the nodes with surplus pages have no free pages.
-	 * free_pool_huge_page() will balance the the frees across the
-	 * on-line nodes for us and will handle the hstate accounting.
+	 * evenly across all nodes with memory. Iterate across these nodes
+	 * until we can no longer free unreserved surplus pages. This occurs
+	 * when the nodes with surplus pages have no free pages.
+	 * free_pool_huge_page() will balance the the freed pages across the
+	 * on-line nodes with memory and will handle the hstate accounting.
 	 */
 	while (nr_pages--) {
-		if (!free_pool_huge_page(h, &node_online_map, 1))
+		if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1))
 			break;
 	}
 }
@@ -1053,14 +1053,14 @@
 int __weak alloc_bootmem_huge_page(struct hstate *h)
 {
 	struct huge_bootmem_page *m;
-	int nr_nodes = nodes_weight(node_online_map);
+	int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
 
 	while (nr_nodes) {
 		void *addr;
 
 		addr = __alloc_bootmem_node_nopanic(
 				NODE_DATA(hstate_next_node_to_alloc(h,
-							&node_online_map)),
+						&node_states[N_HIGH_MEMORY])),
 				huge_page_size(h), huge_page_size(h), 0);
 
 		if (addr) {
@@ -1115,7 +1115,8 @@
 		if (h->order >= MAX_ORDER) {
 			if (!alloc_bootmem_huge_page(h))
 				break;
-		} else if (!alloc_fresh_huge_page(h, &node_online_map))
+		} else if (!alloc_fresh_huge_page(h,
+					 &node_states[N_HIGH_MEMORY]))
 			break;
 	}
 	h->max_huge_pages = i;
@@ -1388,7 +1389,7 @@
 
 	h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
 
-	if (nodes_allowed != &node_online_map)
+	if (nodes_allowed != &node_states[N_HIGH_MEMORY])
 		NODEMASK_FREE(nodes_allowed);
 
 	return len;
@@ -1610,7 +1611,7 @@
 	struct node_hstate *nhs = &node_hstates[node->sysdev.id];
 
 	if (!nhs->hugepages_kobj)
-		return;
+		return;		/* no hstate attributes */
 
 	for_each_hstate(h)
 		if (nhs->hstate_kobjs[h - hstates]) {
@@ -1675,15 +1676,15 @@
 }
 
 /*
- * hugetlb init time:  register hstate attributes for all registered
- * node sysdevs.  All on-line nodes should have registered their
- * associated sysdev by the time the hugetlb module initializes.
+ * hugetlb init time:  register hstate attributes for all registered node
+ * sysdevs of nodes that have memory.  All on-line nodes should have
+ * registered their associated sysdev by this time.
  */
 static void hugetlb_register_all_nodes(void)
 {
 	int nid;
 
-	for (nid = 0; nid < nr_node_ids; nid++) {
+	for_each_node_state(nid, N_HIGH_MEMORY) {
 		struct node *node = &node_devices[nid];
 		if (node->sysdev.id == nid)
 			hugetlb_register_node(node);
@@ -1777,8 +1778,8 @@
 	h->free_huge_pages = 0;
 	for (i = 0; i < MAX_NUMNODES; ++i)
 		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
-	h->next_nid_to_alloc = first_node(node_online_map);
-	h->next_nid_to_free = first_node(node_online_map);
+	h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
+	h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
 	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
 					huge_page_size(h)/1024);