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, 13 deletions

diff --git a/drivers/acpi/acpica/nssearch.c b/drivers/acpi/acpica/nssearch.c
index a8e42b5e9463..41102a84272f 100644
--- a/drivers/acpi/acpica/nssearch.c
+++ b/drivers/acpi/acpica/nssearch.c
@@ -152,17 +152,6 @@ acpi_ns_search_one_scope(u32 target_name,
                         return_ACPI_STATUS(AE_OK);
                 }
 
-                /*
-                 * The last entry in the list points back to the parent,
-                 * so a flag is used to indicate the end-of-list
-                 */
-                if (node->flags & ANOBJ_END_OF_PEER_LIST) {
-
-                        /* Searched entire list, we are done */
-
-                        break;
-                }
-
                 /* Didn't match name, move on to the next peer object */
 
                 node = node->peer;
@@ -217,7 +206,7 @@ acpi_ns_search_parent_tree(u32 target_name,
 
         ACPI_FUNCTION_TRACE(ns_search_parent_tree);
 
-        parent_node = acpi_ns_get_parent_node(node);
+        parent_node = node->parent;
 
         /*
          * If there is no parent (i.e., we are at the root) or type is "local",
@@ -261,7 +250,7 @@ acpi_ns_search_parent_tree(u32 target_name,
 
                 /* Not found here, go up another level (until we reach the root) */
 
-                parent_node = acpi_ns_get_parent_node(parent_node);
+                parent_node = parent_node->parent;
         }
 
         /* Not found in parent tree */