[PATCH] x86_64: Clear more state when ignoring empty node in SRAT parsing

Might fix boot failures on systems with empty PXMs in SRAT
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/mm/srat.c

@@ -26,6 +26,10 @@ static nodemask_t nodes_found __initdata;
 static struct node nodes[MAX_NUMNODES] __initdata;
 static u8 pxm2node[256] = { [0 ... 255] = 0xff };
 
+/* Too small nodes confuse the VM badly. Usually they result
+   from BIOS bugs. */
+#define NODE_MIN_SIZE (4*1024*1024)
+
 static int node_to_pxm(int n);
 
 int pxm_to_node(int pxm)
@@ -223,6 +227,16 @@ static int nodes_cover_memory(void)
 	return 1;
 }
 
+static void unparse_node(int node)
+{
+	int i;
+	node_clear(node, nodes_parsed);
+	for (i = 0; i < MAX_LOCAL_APIC; i++) {
+		if (apicid_to_node[i] == node)
+			apicid_to_node[i] = NUMA_NO_NODE;
+	}
+}
+
 void __init acpi_numa_arch_fixup(void) {}
 
 /* Use the information discovered above to actually set up the nodes. */
@@ -230,16 +244,16 @@ int __init acpi_scan_nodes(unsigned long start, unsigned long end)
 {
 	int i;
 
-	if (acpi_numa <= 0)
-		return -1;
-
 	/* First clean up the node list */
-	for_each_node_mask(i, nodes_parsed) {
+	for (i = 0; i < MAX_NUMNODES; i++) {
 		cutoff_node(i, start, end);
-		if (nodes[i].start == nodes[i].end)
-			node_clear(i, nodes_parsed);
+		if ((nodes[i].end - nodes[i].start) < NODE_MIN_SIZE)
+			unparse_node(i);
 	}
 
+	if (acpi_numa <= 0)
+		return -1;
+
 	if (!nodes_cover_memory()) {
 		bad_srat();
 		return -1;