diff --git a/sys/cddl/compat/opensolaris/sys/mutex.h b/sys/cddl/compat/opensolaris/sys/mutex.h
index 8756cd0534f4..56c41a4f5e9d 100644
--- a/sys/cddl/compat/opensolaris/sys/mutex.h
+++ b/sys/cddl/compat/opensolaris/sys/mutex.h
@@ -47,9 +47,9 @@ typedef enum {
 typedef struct sx	kmutex_t;
 
 #ifndef DEBUG
-#define	MUTEX_FLAGS	(SX_DUPOK | SX_NOWITNESS)
+#define	MUTEX_FLAGS	(SX_DUPOK | SX_NOWITNESS | SX_ADAPTIVESPIN)
 #else
-#define	MUTEX_FLAGS	(SX_DUPOK)
+#define	MUTEX_FLAGS	(SX_DUPOK | SX_ADAPTIVESPIN)
 #endif
 
 #define	mutex_init(lock, desc, type, arg)	do {			\
diff --git a/sys/cddl/compat/opensolaris/sys/rwlock.h b/sys/cddl/compat/opensolaris/sys/rwlock.h
index a3e55153bbcf..0d4ac2e1e2a9 100644
--- a/sys/cddl/compat/opensolaris/sys/rwlock.h
+++ b/sys/cddl/compat/opensolaris/sys/rwlock.h
@@ -49,9 +49,9 @@ typedef enum {
 typedef	struct sx	krwlock_t;
 
 #ifndef DEBUG
-#define	RW_FLAGS	(SX_DUPOK | SX_NOWITNESS)
+#define	RW_FLAGS	(SX_DUPOK | SX_NOWITNESS | SX_ADAPTIVESPIN)
 #else
-#define	RW_FLAGS	(SX_DUPOK)
+#define	RW_FLAGS	(SX_DUPOK | SX_ADAPTIVESPIN)
 #endif
 
 #define	RW_READ_HELD(x)		(rw_read_held((x)))