svn commit: r324609 - head/sys/sys

[Mateusz Guzik]

Author: mjg
Date: Fri Oct 13 20:31:56 2017
New Revision: 324609
URL: https://svnweb.freebsd.org/changeset/base/324609

Log:
  mtx: change MTX_UNOWNED from 4 to 0
  
  The value is spread all over the kernel and zeroing a register is
  cheaper/shorter than setting it up to an arbitrary value.
  
  Reduces amd64 GENERIC-NODEBUG .text size by 0.4%.
  
  MFC after:	1 week

Modified:
  head/sys/sys/mutex.h

Modified: head/sys/sys/mutex.h
==============================================================================
--- head/sys/sys/mutex.h	Fri Oct 13 20:29:35 2017	(r324608)
+++ head/sys/sys/mutex.h	Fri Oct 13 20:31:56 2017	(r324609)
@@ -65,15 +65,11 @@
  * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
  * with the exception of MTX_UNOWNED, applies to spin locks.
  */
+#define	MTX_UNOWNED	0x00000000	/* Cookie for free mutex */
 #define	MTX_RECURSED	0x00000001	/* lock recursed (for MTX_DEF only) */
 #define	MTX_CONTESTED	0x00000002	/* lock contested (for MTX_DEF only) */
-#define MTX_UNOWNED	0x00000004	/* Cookie for free mutex */
-#define	MTX_FLAGMASK	(MTX_RECURSED | MTX_CONTESTED | MTX_UNOWNED)
-
-/*
- * Value stored in mutex->mtx_lock to denote a destroyed mutex.
- */
-#define	MTX_DESTROYED	(MTX_CONTESTED | MTX_UNOWNED)
+#define	MTX_DESTROYED	0x00000004	/* lock destroyed */
+#define	MTX_FLAGMASK	(MTX_RECURSED | MTX_CONTESTED | MTX_DESTROYED)
 
 /*
  * Prototypes