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, 3 deletions

diff --git a/drivers/acpi/acpica/nsaccess.c b/drivers/acpi/acpica/nsaccess.c
index 2cebfa94b79a..0cd925be5fc1 100644
--- a/drivers/acpi/acpica/nsaccess.c
+++ b/drivers/acpi/acpica/nsaccess.c
@@ -338,8 +338,7 @@ acpi_ns_lookup(union acpi_generic_state *scope_info,
                          */
                         while (!acpi_ns_opens_scope(prefix_node->type) &&
                                prefix_node->type != ACPI_TYPE_ANY) {
-                                prefix_node =
-                                    acpi_ns_get_parent_node(prefix_node);
+                                prefix_node = prefix_node->parent;
                         }
                 }
         }
@@ -419,7 +418,7 @@ acpi_ns_lookup(union acpi_generic_state *scope_info,
                                 /* Backup to the parent node */
 
                                 num_carats++;
-                                this_node = acpi_ns_get_parent_node(this_node);
+                                this_node = this_node->parent;
                                 if (!this_node) {
 
                                         /* Current scope has no parent scope */