<sys/dkstat.h> is of very low value - and its name is quite misleading, since it has nothing to do with disk statistics those days.
The following diff removes unnecessary inclusion of this header in the kernel, and removes unused DK_NDRIVE constant. Index: sys/arch/amd64/amd64/autoconf.c =================================================================== RCS file: /cvs/src/sys/arch/amd64/amd64/autoconf.c,v retrieving revision 1.36 diff -u -p -r1.36 autoconf.c --- sys/arch/amd64/amd64/autoconf.c 7 Sep 2010 16:22:48 -0000 1.36 +++ sys/arch/amd64/amd64/autoconf.c 11 Nov 2010 09:47:49 -0000 @@ -47,7 +47,6 @@ #include <sys/param.h> #include <sys/systm.h> #include <sys/buf.h> -#include <sys/dkstat.h> #include <sys/disklabel.h> #include <sys/conf.h> #include <sys/device.h> Index: sys/arch/aviion/aviion/autoconf.c =================================================================== RCS file: /cvs/src/sys/arch/aviion/aviion/autoconf.c,v retrieving revision 1.11 diff -u -p -r1.11 autoconf.c --- sys/arch/aviion/aviion/autoconf.c 18 Apr 2010 15:05:26 -0000 1.11 +++ sys/arch/aviion/aviion/autoconf.c 11 Nov 2010 09:47:51 -0000 @@ -34,7 +34,6 @@ #include <sys/param.h> #include <sys/systm.h> #include <sys/buf.h> -#include <sys/dkstat.h> #include <sys/reboot.h> #include <sys/conf.h> #include <sys/device.h> Index: sys/arch/i386/i386/autoconf.c =================================================================== RCS file: /cvs/src/sys/arch/i386/i386/autoconf.c,v retrieving revision 1.85 diff -u -p -r1.85 autoconf.c --- sys/arch/i386/i386/autoconf.c 25 Jul 2010 21:43:35 -0000 1.85 +++ sys/arch/i386/i386/autoconf.c 11 Nov 2010 09:47:55 -0000 @@ -48,7 +48,6 @@ #include <sys/proc.h> #include <sys/user.h> #include <sys/buf.h> -#include <sys/dkstat.h> #include <sys/disklabel.h> #include <sys/conf.h> #include <sys/reboot.h> Index: sys/arch/luna88k/luna88k/autoconf.c =================================================================== RCS file: /cvs/src/sys/arch/luna88k/luna88k/autoconf.c,v retrieving revision 1.16 diff -u -p -r1.16 autoconf.c --- sys/arch/luna88k/luna88k/autoconf.c 26 Oct 2009 20:17:27 -0000 1.16 +++ sys/arch/luna88k/luna88k/autoconf.c 11 Nov 2010 09:47:57 -0000 @@ -34,7 +34,6 @@ #include <sys/param.h> #include <sys/systm.h> #include <sys/buf.h> -#include <sys/dkstat.h> #include <sys/reboot.h> #include <sys/conf.h> #include <sys/device.h> Index: sys/arch/mvme68k/dev/osiop_mvme68k.c =================================================================== RCS file: /cvs/src/sys/arch/mvme68k/dev/osiop_mvme68k.c,v retrieving revision 1.3 diff -u -p -r1.3 osiop_mvme68k.c --- sys/arch/mvme68k/dev/osiop_mvme68k.c 1 Mar 2009 21:39:59 -0000 1.3 +++ sys/arch/mvme68k/dev/osiop_mvme68k.c 11 Nov 2010 09:48:01 -0000 @@ -28,7 +28,6 @@ #include <sys/systm.h> #include <sys/device.h> #include <sys/disklabel.h> -#include <sys/dkstat.h> #include <scsi/scsi_all.h> #include <scsi/scsiconf.h> Index: sys/arch/mvme68k/dev/sbic.c =================================================================== RCS file: /cvs/src/sys/arch/mvme68k/dev/sbic.c,v retrieving revision 1.28 diff -u -p -r1.28 sbic.c --- sys/arch/mvme68k/dev/sbic.c 29 Jun 2010 21:12:01 -0000 1.28 +++ sys/arch/mvme68k/dev/sbic.c 11 Nov 2010 09:48:01 -0000 @@ -55,7 +55,6 @@ #include <sys/device.h> #include <sys/kernel.h> /* For hz */ #include <sys/disklabel.h> -#include <sys/dkstat.h> #include <sys/buf.h> #include <sys/queue.h> #include <scsi/scsi_all.h> Index: sys/arch/mvme68k/dev/vs.c =================================================================== RCS file: /cvs/src/sys/arch/mvme68k/dev/vs.c,v retrieving revision 1.33 diff -u -p -r1.33 vs.c --- sys/arch/mvme68k/dev/vs.c 28 Jun 2010 18:31:01 -0000 1.33 +++ sys/arch/mvme68k/dev/vs.c 11 Nov 2010 09:48:02 -0000 @@ -45,7 +45,6 @@ #include <sys/systm.h> #include <sys/device.h> #include <sys/disklabel.h> -#include <sys/dkstat.h> #include <sys/buf.h> #include <sys/malloc.h> Index: sys/arch/mvme68k/mvme68k/autoconf.c =================================================================== RCS file: /cvs/src/sys/arch/mvme68k/mvme68k/autoconf.c,v retrieving revision 1.45 diff -u -p -r1.45 autoconf.c --- sys/arch/mvme68k/mvme68k/autoconf.c 26 Oct 2009 20:17:27 -0000 1.45 +++ sys/arch/mvme68k/mvme68k/autoconf.c 11 Nov 2010 09:48:02 -0000 @@ -74,7 +74,6 @@ #include <sys/extent.h> #include <sys/malloc.h> #include <sys/buf.h> -#include <sys/dkstat.h> #include <sys/conf.h> #include <sys/reboot.h> #include <sys/device.h> Index: sys/arch/mvme88k/dev/osiop_pcctwo.c =================================================================== RCS file: /cvs/src/sys/arch/mvme88k/dev/osiop_pcctwo.c,v retrieving revision 1.5 diff -u -p -r1.5 osiop_pcctwo.c --- sys/arch/mvme88k/dev/osiop_pcctwo.c 8 May 2006 14:36:10 -0000 1.5 +++ sys/arch/mvme88k/dev/osiop_pcctwo.c 11 Nov 2010 09:48:03 -0000 @@ -28,7 +28,6 @@ #include <sys/systm.h> #include <sys/device.h> #include <sys/disklabel.h> -#include <sys/dkstat.h> #include <scsi/scsi_all.h> #include <scsi/scsiconf.h> Index: sys/arch/mvme88k/dev/vs.c =================================================================== RCS file: /cvs/src/sys/arch/mvme88k/dev/vs.c,v retrieving revision 1.81 diff -u -p -r1.81 vs.c --- sys/arch/mvme88k/dev/vs.c 28 Jun 2010 18:31:01 -0000 1.81 +++ sys/arch/mvme88k/dev/vs.c 11 Nov 2010 09:48:03 -0000 @@ -45,7 +45,6 @@ #include <sys/systm.h> #include <sys/device.h> #include <sys/disklabel.h> -#include <sys/dkstat.h> #include <sys/buf.h> #include <sys/malloc.h> Index: sys/arch/mvme88k/mvme88k/autoconf.c =================================================================== RCS file: /cvs/src/sys/arch/mvme88k/mvme88k/autoconf.c,v retrieving revision 1.45 diff -u -p -r1.45 autoconf.c --- sys/arch/mvme88k/mvme88k/autoconf.c 26 Oct 2009 20:17:27 -0000 1.45 +++ sys/arch/mvme88k/mvme88k/autoconf.c 11 Nov 2010 09:48:03 -0000 @@ -34,7 +34,6 @@ #include <sys/param.h> #include <sys/systm.h> #include <sys/buf.h> -#include <sys/dkstat.h> #include <sys/reboot.h> #include <sys/conf.h> #include <sys/device.h> Index: sys/arch/solbourne/solbourne/autoconf.c =================================================================== RCS file: /cvs/src/sys/arch/solbourne/solbourne/autoconf.c,v retrieving revision 1.11 diff -u -p -r1.11 autoconf.c --- sys/arch/solbourne/solbourne/autoconf.c 26 Jun 2010 23:24:44 -0000 1.11 +++ sys/arch/solbourne/solbourne/autoconf.c 11 Nov 2010 09:48:05 -0000 @@ -50,7 +50,6 @@ #include <sys/disklabel.h> #include <sys/device.h> #include <sys/disk.h> -#include <sys/dkstat.h> #include <sys/conf.h> #include <sys/reboot.h> #include <sys/socket.h> Index: sys/arch/sparc/dev/fd.c =================================================================== RCS file: /cvs/src/sys/arch/sparc/dev/fd.c,v retrieving revision 1.79 diff -u -p -r1.79 fd.c --- sys/arch/sparc/dev/fd.c 28 Sep 2010 12:39:17 -0000 1.79 +++ sys/arch/sparc/dev/fd.c 11 Nov 2010 09:48:06 -0000 @@ -77,7 +77,6 @@ #include <sys/ioctl.h> #include <sys/device.h> #include <sys/disklabel.h> -#include <sys/dkstat.h> #include <sys/disk.h> #include <sys/buf.h> #include <sys/malloc.h> Index: sys/arch/sparc/sparc/autoconf.c =================================================================== RCS file: /cvs/src/sys/arch/sparc/sparc/autoconf.c,v retrieving revision 1.92 diff -u -p -r1.92 autoconf.c --- sys/arch/sparc/sparc/autoconf.c 10 Jul 2010 19:32:24 -0000 1.92 +++ sys/arch/sparc/sparc/autoconf.c 11 Nov 2010 09:48:08 -0000 @@ -50,7 +50,6 @@ #include <sys/disklabel.h> #include <sys/device.h> #include <sys/disk.h> -#include <sys/dkstat.h> #include <sys/conf.h> #include <sys/reboot.h> #include <sys/socket.h> Index: sys/arch/sparc64/sparc64/autoconf.c =================================================================== RCS file: /cvs/src/sys/arch/sparc64/sparc64/autoconf.c,v retrieving revision 1.108 diff -u -p -r1.108 autoconf.c --- sys/arch/sparc64/sparc64/autoconf.c 7 Aug 2010 00:13:09 -0000 1.108 +++ sys/arch/sparc64/sparc64/autoconf.c 11 Nov 2010 09:48:12 -0000 @@ -50,7 +50,6 @@ #include <sys/disklabel.h> #include <sys/device.h> #include <sys/disk.h> -#include <sys/dkstat.h> #include <sys/conf.h> #include <sys/reboot.h> #include <sys/socket.h> Index: sys/arch/vax/qbus/uba.c =================================================================== RCS file: /cvs/src/sys/arch/vax/qbus/uba.c,v retrieving revision 1.12 diff -u -p -r1.12 uba.c --- sys/arch/vax/qbus/uba.c 26 Jun 2010 23:24:44 -0000 1.12 +++ sys/arch/vax/qbus/uba.c 11 Nov 2010 09:48:16 -0000 @@ -41,7 +41,6 @@ #include <sys/buf.h> #include <sys/proc.h> #include <sys/conf.h> -#include <sys/dkstat.h> #include <sys/kernel.h> #include <sys/malloc.h> #include <sys/device.h> Index: sys/arch/vax/vsa/vsbus.c =================================================================== RCS file: /cvs/src/sys/arch/vax/vsa/vsbus.c,v retrieving revision 1.20 diff -u -p -r1.20 vsbus.c --- sys/arch/vax/vsa/vsbus.c 30 Aug 2008 20:45:31 -0000 1.20 +++ sys/arch/vax/vsa/vsbus.c 11 Nov 2010 09:48:17 -0000 @@ -42,7 +42,6 @@ #include <sys/proc.h> #include <sys/user.h> #include <sys/device.h> -#include <sys/dkstat.h> #include <sys/disklabel.h> #include <sys/syslog.h> #include <sys/stat.h> Index: sys/ddb/db_structinfo.c =================================================================== RCS file: /cvs/src/sys/ddb/db_structinfo.c,v retrieving revision 1.3 diff -u -p -r1.3 db_structinfo.c --- sys/ddb/db_structinfo.c 28 Jun 2010 23:00:30 -0000 1.3 +++ sys/ddb/db_structinfo.c 11 Nov 2010 09:48:17 -0000 @@ -21,7 +21,6 @@ #include <sys/disklabel.h> #include <sys/dirent.h> #include <sys/dkbad.h> -#include <sys/dkstat.h> #include <sys/evcount.h> #include <sys/event.h> #include <sys/eventvar.h> Index: sys/dev/atapiscsi/atapiscsi.c =================================================================== RCS file: /cvs/src/sys/dev/atapiscsi/atapiscsi.c,v retrieving revision 1.95 diff -u -p -r1.95 atapiscsi.c --- sys/dev/atapiscsi/atapiscsi.c 20 Sep 2010 06:17:49 -0000 1.95 +++ sys/dev/atapiscsi/atapiscsi.c 11 Nov 2010 09:48:18 -0000 @@ -36,9 +36,7 @@ #include <sys/kernel.h> #include <sys/device.h> #include <sys/buf.h> -#include <sys/dkstat.h> #include <sys/disklabel.h> -#include <sys/dkstat.h> #include <sys/malloc.h> #include <sys/proc.h> #include <sys/reboot.h> Index: sys/dev/isa/fd.c =================================================================== RCS file: /cvs/src/sys/dev/isa/fd.c,v retrieving revision 1.89 diff -u -p -r1.89 fd.c --- sys/dev/isa/fd.c 23 Sep 2010 13:11:37 -0000 1.89 +++ sys/dev/isa/fd.c 11 Nov 2010 09:48:22 -0000 @@ -49,7 +49,6 @@ #include <sys/ioctl.h> #include <sys/device.h> #include <sys/disklabel.h> -#include <sys/dkstat.h> #include <sys/disk.h> #include <sys/buf.h> #include <sys/malloc.h> Index: sys/dev/isa/fdc.c =================================================================== RCS file: /cvs/src/sys/dev/isa/fdc.c,v retrieving revision 1.17 diff -u -p -r1.17 fdc.c --- sys/dev/isa/fdc.c 19 Sep 2005 01:28:04 -0000 1.17 +++ sys/dev/isa/fdc.c 11 Nov 2010 09:48:22 -0000 @@ -49,7 +49,6 @@ #include <sys/ioctl.h> #include <sys/device.h> #include <sys/disklabel.h> -#include <sys/dkstat.h> #include <sys/disk.h> #include <sys/buf.h> #include <sys/malloc.h> Index: sys/kern/subr_disk.c =================================================================== RCS file: /cvs/src/sys/kern/subr_disk.c,v retrieving revision 1.112 diff -u -p -r1.112 subr_disk.c --- sys/kern/subr_disk.c 24 Sep 2010 07:08:50 -0000 1.112 +++ sys/kern/subr_disk.c 11 Nov 2010 09:48:26 -0000 @@ -54,7 +54,6 @@ #include <sys/disk.h> #include <sys/reboot.h> #include <sys/dkio.h> -#include <sys/dkstat.h> /* XXX */ #include <sys/proc.h> #include <sys/vnode.h> #include <sys/workq.h> Index: sys/sys/dkstat.h =================================================================== RCS file: /cvs/src/sys/sys/dkstat.h,v retrieving revision 1.7 diff -u -p -r1.7 dkstat.h --- sys/sys/dkstat.h 2 Jun 2003 23:28:21 -0000 1.7 +++ sys/sys/dkstat.h 11 Nov 2010 09:48:27 -0000 @@ -44,7 +44,6 @@ #define CP_IDLE 4 #define CPUSTATES 5 -#define DK_NDRIVE 8 #ifdef _KERNEL extern long cp_time[CPUSTATES];
