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, 3 insertions, 2 deletions

diff --git a/drivers/acpi/acpica/aclocal.h b/drivers/acpi/acpica/aclocal.h
index 147a7e6bd38f..eb2d420b39ec 100644
--- a/drivers/acpi/acpica/aclocal.h
+++ b/drivers/acpi/acpica/aclocal.h
@@ -184,8 +184,9 @@ struct acpi_namespace_node {
         u8 flags;               /* Miscellaneous flags */
         acpi_owner_id owner_id; /* Node creator */
         union acpi_name_union name;     /* ACPI Name, always 4 chars per ACPI spec */
+        struct acpi_namespace_node *parent;     /* Parent node */
         struct acpi_namespace_node *child;      /* First child */
-        struct acpi_namespace_node *peer;       /* Peer. Parent if ANOBJ_END_OF_PEER_LIST set */
+        struct acpi_namespace_node *peer;       /* First peer */
 
         /*
          * The following fields are used by the ASL compiler and disassembler only
@@ -199,7 +200,7 @@ struct acpi_namespace_node {
 
 /* Namespace Node flags */
 
-#define ANOBJ_END_OF_PEER_LIST          0x01    /* End-of-list, Peer field points to parent */
+#define ANOBJ_RESERVED                  0x01    /* Available for use */
 #define ANOBJ_TEMPORARY                 0x02    /* Node is create by a method and is temporary */
 #define ANOBJ_METHOD_ARG                0x04    /* Node is a method argument */
 #define ANOBJ_METHOD_LOCAL              0x08    /* Node is a method local */