[PATCH] Handle holes in node mask in node fallback list setup
Change the find_next_best_node algorithm to correctly skip
over holes in the node online mask. Previously it would not handle
missing nodes correctly and cause crashes at boot.
[Written by Linus, tested by AK]
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 62c1225..208812b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1541,29 +1541,29 @@
*/
static int __init find_next_best_node(int node, nodemask_t *used_node_mask)
{
- int i, n, val;
+ int n, val;
int min_val = INT_MAX;
int best_node = -1;
- for_each_online_node(i) {
- cpumask_t tmp;
+ /* Use the local node if we haven't already */
+ if (!node_isset(node, *used_node_mask)) {
+ node_set(node, *used_node_mask);
+ return node;
+ }
- /* Start from local node */
- n = (node+i) % num_online_nodes();
+ for_each_online_node(n) {
+ cpumask_t tmp;
/* Don't want a node to appear more than once */
if (node_isset(n, *used_node_mask))
continue;
- /* Use the local node if we haven't already */
- if (!node_isset(node, *used_node_mask)) {
- best_node = node;
- break;
- }
-
/* Use the distance array to find the distance */
val = node_distance(node, n);
+ /* Penalize nodes under us ("prefer the next node") */
+ val += (n < node);
+
/* Give preference to headless and unused nodes */
tmp = node_to_cpumask(n);
if (!cpus_empty(tmp))