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>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/acpi/acpica/nsnames.c b/drivers/acpi/acpica/nsnames.c
index 7dea0031605c..d3104af57e13 100644
--- a/drivers/acpi/acpica/nsnames.c
+++ b/drivers/acpi/acpica/nsnames.c
@@ -93,7 +93,7 @@ acpi_ns_build_external_path(struct acpi_namespace_node *node,
                 /* Put the name into the buffer */
 
                 ACPI_MOVE_32_TO_32((name_buffer + index), &parent_node->name);
-                parent_node = acpi_ns_get_parent_node(parent_node);
+                parent_node = parent_node->parent;
 
                 /* Prefix name with the path separator */
 
@@ -198,7 +198,7 @@ acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
                         return 0;
                 }
                 size += ACPI_PATH_SEGMENT_LENGTH;
-                next_node = acpi_ns_get_parent_node(next_node);
+                next_node = next_node->parent;
         }
 
         if (!size) {