1 files changed, 44 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6fe1b65ee1a..431214b941a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -62,6 +62,17 @@ DEFINE_PER_CPU(int, numa_node);
 EXPORT_PER_CPU_SYMBOL(numa_node);
 #endif
 
+#ifdef CONFIG_HAVE_MEMORYLESS_NODES
+/*
+ * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
+ * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
+ * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
+ * defined in <linux/topology.h>.
+ */
+DEFINE_PER_CPU(int, _numa_mem_);		/* Kernel "local memory" node */
+EXPORT_PER_CPU_SYMBOL(_numa_mem_);
+#endif
+
 /*
  * Array of node states.
  */
@@ -2861,6 +2872,24 @@ static void build_zonelist_cache(pg_data_t *pgdat)
 		zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
 }
 
+#ifdef CONFIG_HAVE_MEMORYLESS_NODES
+/*
+ * Return node id of node used for "local" allocations.
+ * I.e., first node id of first zone in arg node's generic zonelist.
+ * Used for initializing percpu 'numa_mem', which is used primarily
+ * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
+ */
+int local_memory_node(int node)
+{
+	struct zone *zone;
+
+	(void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
+				   gfp_zone(GFP_KERNEL),
+				   NULL,
+				   &zone);
+	return zone->node;
+}
+#endif
 
 #else	/* CONFIG_NUMA */
 
@@ -2975,9 +3004,23 @@ static __init_refok int __build_all_zonelists(void *data)
 	 * needs the percpu allocator in order to allocate its pagesets
 	 * (a chicken-egg dilemma).
 	 */
-	for_each_possible_cpu(cpu)
+	for_each_possible_cpu(cpu) {
 		setup_pageset(&per_cpu(boot_pageset, cpu), 0);
 
+#ifdef CONFIG_HAVE_MEMORYLESS_NODES
+		/*
+		 * We now know the "local memory node" for each node--
+		 * i.e., the node of the first zone in the generic zonelist.
+		 * Set up numa_mem percpu variable for on-line cpus.  During
+		 * boot, only the boot cpu should be on-line;  we'll init the
+		 * secondary cpus' numa_mem as they come on-line.  During
+		 * node/memory hotplug, we'll fixup all on-line cpus.
+		 */
+		if (cpu_online(cpu))
+			set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
+#endif
+	}
+
 	return 0;
 }