Index: head/sys/conf/NOTES
===================================================================
--- head/sys/conf/NOTES	(revision 221756)
+++ head/sys/conf/NOTES	(working copy)
@@ -173,6 +173,9 @@ options 	GEOM_VIRSTOR		# Virtual storage.
 options 	GEOM_VOL		# Volume names from UFS superblock
 options 	GEOM_ZERO		# Performance testing helper.
 
+# GEOM_NODEBUG disables most of GEOM debug messages
+#options	GEOM_NODEBUG
+
 #
 # The root device and filesystem type can be compiled in;
 # this provides a fallback option if the root device cannot
Index: head/sys/conf/options
===================================================================
--- head/sys/conf/options	(revision 221756)
+++ head/sys/conf/options	(working copy)
@@ -92,6 +92,7 @@ GEOM_LINUX_LVM	opt_geom.h
 GEOM_MBR	opt_geom.h
 GEOM_MIRROR	opt_geom.h
 GEOM_MULTIPATH	opt_geom.h
+GEOM_NODEBUG	opt_geom.h
 GEOM_NOP	opt_geom.h
 GEOM_PART_APM	opt_geom.h
 GEOM_PART_BSD	opt_geom.h
Index: head/sys/geom/geom.h
===================================================================
--- head/sys/geom/geom.h	(revision 221756)
+++ head/sys/geom/geom.h	(working copy)
@@ -371,6 +371,41 @@ g_free(void *ptr)
 	};							\
 	DECLARE_MODULE(name, name##_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
 
+#define	G_MSG(class, ...)	do {					\
+	printf("GEOM_%s: ", (class));					\
+	printf(__VA_ARGS__);						\
+	printf("\n");							\
+} while (0)
+
+#ifdef	GEOM_NODEBUG
+#define G_DEBUG(...)
+#define G_LOGREQ(...)
+#define G_TRACE(...)
+#else
+#define	G_DEBUG(class, debugctl, lvl, ...)	do {			\
+	if ((debugctl) >= (lvl)) {					\
+		printf("GEOM_%s[%u]: ", (class), (lvl));		\
+		printf(__VA_ARGS__);					\
+		printf("\n");						\
+	}								\
+} while (0)
+#define 	G_LOGREQ(class, debugctl, lvl, bp, ...)	do {			\
+	if ((debugctl) >= (lvl)) {					\
+		printf("GEOM_%s[%u]: ", (class), (lvl));		\
+		printf(__VA_ARGS__);					\
+		printf(" ");						\
+		g_print_bio(bp);					\
+		printf("\n");						\
+	}								\
+} while (0)
+#define	G_TRACE(class, lvl, ...)	do {				\
+	if ((g_debugflags & (lvl)) != 0) {				\
+		printf("GEOM_%s: ", (class));				\
+		g_trace((lvl), __VA_ARGS__);				\
+	}								\
+} while (0)
+#endif /* GEOM_NODEBUG */
+
 #endif /* _KERNEL */
 
 /* geom_ctl.c */