Issue

• The value of "RECLAIM_DISTANCE" is set to "20" in Red Hat Enterprise Linux 6 kernel.

Source: kernel-2.6.32-358.18.1.el6/tree/include/linux/topology.h#line-62

* If the distance between nodes in a system is larger than RECLAIM_DISTANCE
* (in whatever arch specific measurement units returned by node_distance())
* then switch on zone reclaim on boot.
*/
#define RECLAIM_DISTANCE 20

• But in upstream kernel the value of RECLAIM_DISTANCE is set to "30".

diff --git a/include/linux/topology.h b/include/linux/topology.h
index b91a40e..fc839bf 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -60,7 +60,7 @@ int arch_update_cpu_topology(void);
* (in whatever arch specific measurement units returned by node_distance())
* then switch on zone reclaim on boot.
*/
-#define RECLAIM_DISTANCE 20
+#define RECLAIM_DISTANCE 30
#endif
#ifndef PENALTY_FOR_NODE_WITH_CPUS
#define PENALTY_FOR_NODE_WITH_CPUS (1)

• Increase RECLAIM_DISTANCE to 30 in Red Hat Enterprise Linux 6 kernel.