[PATCH] lockdep: core, reduce per-lock class-cache size

lockdep_map is embedded into every lock, which blows up data structure
sizes all around the kernel.  Reduce the class-cache to be for the default
class only - that is used in 99.9% of the cases and even if we dont have a
class cached, the lookup in the class-hash is lockless.

This change reduces the per-lock dep_map overhead by 56 bytes on 64-bit
platforms and by 28 bytes on 32-bit platforms.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 316e0fb8d7b..c040a8c969a 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -120,7 +120,7 @@ struct lock_class {
  */
 struct lockdep_map {
         struct lock_class_key           *key;
-        struct lock_class               *class[MAX_LOCKDEP_SUBCLASSES];
+        struct lock_class               *class_cache;
         const char                      *name;
 };