ACPICA: Performance enhancement for namespace search and access

This change enhances the performance of namespace searches and
walks by adding a backpointer to the parent in each namespace
node. On large namespaces, this change can improve overall ACPI
performance by up to 9X.  Adding a pointer to each namespace node
increases the overall size of the internal namespace by about 5%,
since each namespace entry usually consists of both a namespace
node and an ACPI operand object.

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/acpica/nsinit.c

@@ -410,7 +410,7 @@ acpi_ns_find_ini_methods(acpi_handle obj_handle,
 	 * The only _INI methods that we care about are those that are
 	 * present under Device, Processor, and Thermal objects.
 	 */
-	parent_node = acpi_ns_get_parent_node(node);
+	parent_node = node->parent;
 	switch (parent_node->type) {
 	case ACPI_TYPE_DEVICE:
 	case ACPI_TYPE_PROCESSOR:
@@ -420,7 +420,7 @@ acpi_ns_find_ini_methods(acpi_handle obj_handle,
 
 		while (parent_node) {
 			parent_node->flags |= ANOBJ_SUBTREE_HAS_INI;
-			parent_node = acpi_ns_get_parent_node(parent_node);
+			parent_node = parent_node->parent;
 		}
 		break;