[PATCH 2/4] hugetlb: fix pool allocation with empty nodes

[Nishanth Aravamudan <nacc@us.ibm.com>]

Anton found a problem with the hugetlb pool allocation when some nodes
have no memory (http://marc.info/?l=linux-mm&m=118133042025995&w=2). Lee
worked on versions that tried to fix it, but none were accepted.
Christoph has created a set of patches which allow for GFP_THISNODE
allocations to fail if the node has no memory and for exporting a
nodemask indicating which nodes have memory. Simply interleave across
this nodemask rather than the online nodemask.

Tested on 4-node ppc64, 2-node ia64 and 4-node x86_64.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>

---
My 4-node ppc64 box with memoryless nodes is having issues with
2.6.23-rc4-mm1, so I'm unable to test. Lee, could you give this a spin?

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index edb2100..cc875c6 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -129,7 +129,7 @@ static int alloc_fresh_huge_page(void)
 	int ret = 0;
 
 	if (nid < 0)
-		nid = first_node(node_online_map);
+		nid = first_node(node_states[N_HIGH_MEMORY]);
 	start_nid = nid;
 
 	do {
@@ -147,9 +147,9 @@ static int alloc_fresh_huge_page(void)
 		 * successfully allocated a hugepage so that the next
 		 * caller gets hugepages on the next node.
 		 */
-		next_nid = next_node(nid, node_online_map);
+		next_nid = next_node(nid, node_states[N_HIGH_MEMORY]);
 		if (next_nid == MAX_NUMNODES)
-			next_nid = first_node(node_online_map);
+			next_nid = first_node(node_states[N_HIGH_MEMORY]);
 		nid = next_nid;
 	} while (!page && nid != start_nid);
 

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