#define MAX_LOCKDEP_SUBCLASSES 8UL
+/*
+ * NR_LOCKDEP_CACHING_CLASSES ... Number of classes
+ * cached in the instance of lockdep_map
+ *
+ * Currently main class (subclass == 0) and signle depth subclass
+ * are cached in lockdep_map. This optimization is mainly targeting
+ * on rq->lock. double_rq_lock() acquires this highly competitive with
+ * single depth.
+ */
+#define NR_LOCKDEP_CACHING_CLASSES 2
+
/*
* Lock-classes are keyed via unique addresses, by embedding the
* lockclass-key into the kernel (or module) .data section. (For
*/
struct lockdep_map {
struct lock_class_key *key;
- struct lock_class *class_cache;
+ struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES];
const char *name;
#ifdef CONFIG_LOCK_STAT
int cpu;