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Initial commit of an I/O provider for DTrace on FreeBSD.

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These probes are most useful when looking into the structures
they provide, which are listed in io.d.  For example:

dtrace -n 'io:genunix::start { printf("%d\n", args[0]->bio_bcount); }'

Note that the I/O systems in FreeBSD and Solaris/Illumos are sufficiently
different that there is not a 1:1 mapping from scripts that work
with one to the other.
MFC after:	1 month
This commit is contained in:
George V. Neville-Neil 2012-07-11 16:27:02 +00:00
parent f5afad7389
commit 3fac94ba94
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=238366
8 changed files with 355 additions and 144 deletions
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1
cddl/lib/libdtrace/Makefile
View File

@ -45,6 +45,7 @@ SRCS= dt_aggregate.c \
gmatch.c
DSRCS= errno.d \
io.d \
psinfo.d \
signal.d \
unistd.d

178
cddl/lib/libdtrace/io.d
View File

@ -27,114 +27,50 @@
#pragma ident "%Z%%M% %I% %E% SMI"
#pragma D depends_on module unix
#pragma D depends_on provider io
inline int B_BUSY = B_BUSY;
#pragma D binding "1.0" B_BUSY
inline int B_DONE = 0x00000200;
#pragma D binding "1.0" B_DONE
inline int B_ERROR = B_ERROR;
#pragma D binding "1.0" B_ERROR
inline int B_PAGEIO = B_PAGEIO;
#pragma D binding "1.0" B_PAGEIO
inline int B_PHYS = B_PHYS;
#pragma D binding "1.0" B_PHYS
inline int B_READ = B_READ;
#pragma D binding "1.0" B_READ
inline int B_WRITE = B_WRITE;
#pragma D binding "1.0" B_WRITE
inline int B_ASYNC = 0x00000004;
#pragma D binding "1.0" B_ASYNC
typedef struct bufinfo {
int b_flags; /* buffer status */
size_t b_bcount; /* number of bytes */
caddr_t b_addr; /* buffer address */
uint64_t b_lblkno; /* block # on device */
uint64_t b_blkno; /* expanded block # on device */
size_t b_resid; /* # of bytes not transferred */
size_t b_bufsize; /* size of allocated buffer */
caddr_t b_iodone; /* I/O completion routine */
int b_error; /* expanded error field */
dev_t b_edev; /* extended device */
} bufinfo_t;
#pragma D binding "1.0" translator
translator bufinfo_t < struct buf *B > {
b_flags = B->b_flags;
b_addr = B->b_un.b_addr;
b_bcount = B->b_bcount;
b_lblkno = B->_b_blkno._f;
b_blkno = sizeof (long) == 8 ? B->_b_blkno._f : B->_b_blkno._p._l;
b_resid = B->b_resid;
b_bufsize = B->b_bufsize;
b_iodone = (caddr_t)B->b_iodone;
b_error = B->b_error;
b_edev = B->b_edev;
};
typedef struct devinfo {
int dev_major; /* major number */
int dev_minor; /* minor number */
int dev_instance; /* instance number */
string dev_name; /* name of device */
string dev_statname; /* name of device + instance/minor */
string dev_pathname; /* pathname of device */
int dev_major; /* major number */
int dev_minor; /* minor number */
int dev_instance; /* instance number */
string dev_name; /* name of device */
string dev_statname; /* name of device + instance/minor */
string dev_pathname; /* pathname of device */
} devinfo_t;
#pragma D binding "1.0" translator
translator devinfo_t < struct buf *B > {
dev_major = B->b_dip != NULL ? getmajor(B->b_edev) :
getmajor(B->b_file->v_vfsp->vfs_dev);
dev_minor = B->b_dip != NULL ? getminor(B->b_edev) :
getminor(B->b_file->v_vfsp->vfs_dev);
dev_instance = B->b_dip == NULL ?
getminor(B->b_file->v_vfsp->vfs_dev) :
((struct dev_info *)B->b_dip)->devi_instance;
dev_name = B->b_dip == NULL ? "nfs" :
stringof(`devnamesp[getmajor(B->b_edev)].dn_name);
dev_statname = strjoin(B->b_dip == NULL ? "nfs" :
stringof(`devnamesp[getmajor(B->b_edev)].dn_name),
lltostr(B->b_dip == NULL ? getminor(B->b_file->v_vfsp->vfs_dev) :
((struct dev_info *)B->b_dip)->devi_instance == 0 &&
((struct dev_info *)B->b_dip)->devi_parent != NULL &&
((struct dev_info *)B->b_dip)->devi_parent->devi_node_name ==
"pseudo" ? getminor(B->b_edev) :
((struct dev_info *)B->b_dip)->devi_instance));
dev_pathname = B->b_dip == NULL ? "<nfs>" :
ddi_pathname(B->b_dip, getminor(B->b_edev));
translator devinfo_t < struct devstat *D > {
dev_major = D->device_number;
dev_minor = D->unit_number;
dev_instance = 0;
dev_name = stringof(D->device_name);
dev_statname = stringof(D->device_name);
dev_pathname = stringof(D->device_name);
};
typedef struct fileinfo {
string fi_name; /* name (basename of fi_pathname) */
string fi_dirname; /* directory (dirname of fi_pathname) */
string fi_pathname; /* full pathname */
offset_t fi_offset; /* offset within file */
string fi_fs; /* filesystem */
string fi_mount; /* mount point of file system */
int fi_oflags; /* open(2) flags for file descriptor */
} fileinfo_t;
typedef struct bufinfo {
int b_flags; /* flags */
long b_bcount; /* number of bytes */
caddr_t b_addr; /* buffer address */
uint64_t b_blkno; /* expanded block # on device */
uint64_t b_lblkno; /* block # on device */
size_t b_resid; /* # of bytes not transferred */
size_t b_bufsize; /* size of allocated buffer */
/* caddr_t b_iodone; I/O completion routine */
int b_error; /* expanded error field */
/* dev_t b_edev; extended device */
} bufinfo_t;
#pragma D binding "1.0" translator
translator fileinfo_t < struct buf *B > {
fi_name = B->b_file == NULL ? "<none>" :
B->b_file->v_path == NULL ? "<unknown>" :
basename(cleanpath(B->b_file->v_path));
fi_dirname = B->b_file == NULL ? "<none>" :
B->b_file->v_path == NULL ? "<unknown>" :
dirname(cleanpath(B->b_file->v_path));
fi_pathname = B->b_file == NULL ? "<none>" :
B->b_file->v_path == NULL ? "<unknown>" :
cleanpath(B->b_file->v_path);
fi_offset = B->b_offset;
fi_fs = B->b_file == NULL ? "<none>" :
stringof(B->b_file->v_op->vnop_name);
fi_mount = B->b_file == NULL ? "<none>" :
B->b_file->v_vfsp->vfs_vnodecovered == NULL ? "/" :
B->b_file->v_vfsp->vfs_vnodecovered->v_path == NULL ? "<unknown>" :
cleanpath(B->b_file->v_vfsp->vfs_vnodecovered->v_path);
fi_oflags = 0;
translator bufinfo_t < struct bio *B > {
b_flags = B->bio_flags;
b_bcount = B->bio_bcount;
b_addr = B->bio_data;
b_blkno = 0;
b_lblkno = 0;
b_resid = B->bio_resid;
b_bufsize = 0; /* XXX gnn */
b_error = B->bio_error;
};
/*
@ -158,63 +94,17 @@ inline int O_APPEND = 0x0008;
#pragma D binding "1.1" O_APPEND
inline int O_CREAT = 0x0200;
#pragma D binding "1.1" O_CREAT
inline int O_DSYNC = O_DSYNC;
#pragma D binding "1.1" O_DSYNC
inline int O_EXCL = 0x0800;
#pragma D binding "1.1" O_EXCL
inline int O_LARGEFILE = O_LARGEFILE;
#pragma D binding "1.1" O_LARGEFILE
inline int O_NOCTTY = 0x8000;
#pragma D binding "1.1" O_NOCTTY
inline int O_NONBLOCK = 0x0004;
#pragma D binding "1.1" O_NONBLOCK
inline int O_NDELAY = 0x0004;
#pragma D binding "1.1" O_NDELAY
inline int O_RSYNC = O_RSYNC;
#pragma D binding "1.1" O_RSYNC
inline int O_SYNC = 0x0080;
#pragma D binding "1.1" O_SYNC
inline int O_TRUNC = 0x0400;
#pragma D binding "1.1" O_TRUNC
inline int O_XATTR = O_XATTR;
#pragma D binding "1.1" O_XATTR
#pragma D binding "1.1" translator
translator fileinfo_t < struct file *F > {
fi_name = F == NULL ? "<none>" :
F->f_vnode->v_path == NULL ? "<unknown>" :
basename(cleanpath(F->f_vnode->v_path));
fi_dirname = F == NULL ? "<none>" :
F->f_vnode->v_path == NULL ? "<unknown>" :
dirname(cleanpath(F->f_vnode->v_path));
fi_pathname = F == NULL ? "<none>" :
F->f_vnode->v_path == NULL ? "<unknown>" :
cleanpath(F->f_vnode->v_path);
fi_offset = F == NULL ? 0 : F->f_offset;
fi_fs = F == NULL ? "<none>" : stringof(F->f_vnode->v_op->vnop_name);
fi_mount = F == NULL ? "<none>" :
F->f_vnode->v_vfsp->vfs_vnodecovered == NULL ? "/" :
F->f_vnode->v_vfsp->vfs_vnodecovered->v_path == NULL ? "<unknown>" :
cleanpath(F->f_vnode->v_vfsp->vfs_vnodecovered->v_path);
fi_oflags = F == NULL ? 0 : F->f_flag + (int)FOPEN;
};
inline fileinfo_t fds[int fd] = xlate <fileinfo_t> (
fd >= 0 && fd < curthread->t_procp->p_user.u_finfo.fi_nfiles ?
curthread->t_procp->p_user.u_finfo.fi_list[fd].uf_file : NULL);
#pragma D attributes Stable/Stable/Common fds
#pragma D binding "1.1" fds
#pragma D binding "1.2" translator
translator fileinfo_t < struct vnode *V > {
fi_name = V->v_path == NULL ? "<unknown>" :
basename(cleanpath(V->v_path));
fi_dirname = V->v_path == NULL ? "<unknown>" :
dirname(cleanpath(V->v_path));
fi_pathname = V->v_path == NULL ? "<unknown>" : cleanpath(V->v_path);
fi_fs = stringof(V->v_op->vnop_name);
fi_mount = V->v_vfsp->vfs_vnodecovered == NULL ? "/" :
V->v_vfsp->vfs_vnodecovered->v_path == NULL ? "<unknown>" :
cleanpath(V->v_vfsp->vfs_vnodecovered->v_path);
};

232
sys/kern/dtio_kdtrace.c Normal file
View File

@ -0,0 +1,232 @@
/*-
* Copyright (c) 2012 Advanced Computing Technologies LLC
* Written by George Neville-Neil gnn@freebsd.org
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/dtrace.h>
#include "../sys/dtrace_bsd.h"
static int dtio_unload(void);
static void dtio_getargdesc(void *, dtrace_id_t, void *,
dtrace_argdesc_t *);
static void dtio_provide(void *, dtrace_probedesc_t *);
static void dtio_destroy(void *, dtrace_id_t, void *);
static void dtio_enable(void *, dtrace_id_t, void *);
static void dtio_disable(void *, dtrace_id_t, void *);
static void dtio_load(void *);
static dtrace_pattr_t dtio_attr = {
{ DTRACE_STABILITY_STABLE, DTRACE_STABILITY_STABLE, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_STABLE, DTRACE_STABILITY_STABLE, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_STABLE, DTRACE_STABILITY_STABLE, DTRACE_CLASS_COMMON },
};
static char *genunix = "genunix";
/*
* Name strings.
*/
static char *dtio_start_str = "start";
static char *dtio_done_str = "done";
static char *dtio_wait_start_str = "wait-start";
static char *dtio_wait_done_str = "wait-done";
static dtrace_pops_t dtio_pops = {
dtio_provide,
NULL,
dtio_enable,
dtio_disable,
NULL,
NULL,
dtio_getargdesc,
NULL,
NULL,
dtio_destroy
};
static dtrace_provider_id_t dtio_id;
extern uint32_t dtio_start_id;
extern uint32_t dtio_done_id;
extern uint32_t dtio_wait_start_id;
extern uint32_t dtio_wait_done_id;
static void
dtio_getargdesc(void *arg, dtrace_id_t id, void *parg,
dtrace_argdesc_t *desc)
{
const char *p = NULL;
switch (desc->dtargd_ndx) {
case 0:
p = "struct bio *";
break;
case 1:
p = "struct devstat *";
break;
default:
desc->dtargd_ndx = DTRACE_ARGNONE;
}
if (p != NULL)
strlcpy(desc->dtargd_native, p, sizeof(desc->dtargd_native));
}
static void
dtio_provide(void *arg, dtrace_probedesc_t *desc)
{
if (desc != NULL)
return;
if (dtrace_probe_lookup(dtio_id, genunix, NULL,
dtio_start_str) == 0) {
dtio_start_id = dtrace_probe_create(dtio_id, genunix, NULL,
dtio_start_str, 0, NULL);
}
if (dtrace_probe_lookup(dtio_id, genunix, NULL, dtio_done_str) == 0) {
dtio_done_id = dtrace_probe_create(dtio_id, genunix, NULL,
dtio_done_str, 0, NULL);
}
if (dtrace_probe_lookup(dtio_id, genunix, NULL,
dtio_wait_start_str) == 0) {
dtio_wait_start_id = dtrace_probe_create(dtio_id, genunix,
NULL,
dtio_wait_start_str,
0, NULL);
}
if (dtrace_probe_lookup(dtio_id, genunix, NULL,
dtio_wait_done_str) == 0) {
dtio_wait_done_id = dtrace_probe_create(dtio_id, genunix, NULL,
dtio_wait_done_str, 0, NULL);
}
}
static void
dtio_destroy(void *arg, dtrace_id_t id, void *parg)
{
}
static void
dtio_enable(void *arg, dtrace_id_t id, void *parg)
{
if (id == dtio_start_id)
dtrace_io_start_probe =
(dtrace_io_start_probe_func_t)dtrace_probe;
else if (id == dtio_done_id)
dtrace_io_done_probe =
(dtrace_io_done_probe_func_t)dtrace_probe;
else if (id == dtio_wait_start_id)
dtrace_io_wait_start_probe =
(dtrace_io_wait_start_probe_func_t)dtrace_probe;
else if (id == dtio_wait_done_id)
dtrace_io_wait_done_probe =
(dtrace_io_wait_done_probe_func_t)dtrace_probe;
else
printf("dtrace io provider: unknown ID\n");
}
static void
dtio_disable(void *arg, dtrace_id_t id, void *parg)
{
if (id == dtio_start_id)
dtrace_io_start_probe = NULL;
else if (id == dtio_done_id)
dtrace_io_done_probe = NULL;
else if (id == dtio_wait_start_id)
dtrace_io_wait_start_probe = NULL;
else if (id == dtio_wait_done_id)
dtrace_io_wait_done_probe = NULL;
else
printf("dtrace io provider: unknown ID\n");
}
static void
dtio_load(void *dummy)
{
if (dtrace_register("io", &dtio_attr, DTRACE_PRIV_USER, NULL,
&dtio_pops, NULL, &dtio_id) != 0)
return;
}
static int
dtio_unload()
{
dtrace_io_start_probe = NULL;
dtrace_io_done_probe = NULL;
dtrace_io_wait_start_probe = NULL;
dtrace_io_wait_done_probe = NULL;
return (dtrace_unregister(dtio_id));
}
static int
dtio_modevent(module_t mod __unused, int type, void *data __unused)
{
int error = 0;
switch (type) {
case MOD_LOAD:
break;
case MOD_UNLOAD:
break;
case MOD_SHUTDOWN:
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
SYSINIT(dtio_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
dtio_load, NULL);
SYSUNINIT(dtio_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
dtio_unload, NULL);
DEV_MODULE(dtio, dtio_modevent, NULL);
MODULE_VERSION(dtio, 1);
MODULE_DEPEND(dtio, dtrace, 1, 1, 1);
MODULE_DEPEND(dtio, opensolaris, 1, 1, 1);

54
sys/kern/subr_devstat.c
View File

@ -29,6 +29,8 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_kdtrace.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
@ -44,6 +46,54 @@ __FBSDID("$FreeBSD$");
#include <machine/atomic.h>
#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>
dtrace_io_start_probe_func_t dtrace_io_start_probe;
dtrace_io_done_probe_func_t dtrace_io_done_probe;
dtrace_io_wait_start_probe_func_t dtrace_io_wait_start_probe;
dtrace_io_wait_done_probe_func_t dtrace_io_wait_done_probe;
uint32_t dtio_start_id;
uint32_t dtio_done_id;
uint32_t dtio_wait_start_id;
uint32_t dtio_wait_done_id;
#define DTRACE_DEVSTAT_START() \
if (dtrace_io_start_probe != NULL) \
(*dtrace_io_start_probe)(dtio_start_id, NULL, ds);
#define DTRACE_DEVSTAT_BIO_START() \
if (dtrace_io_start_probe != NULL) \
(*dtrace_io_start_probe)(dtio_start_id, bp, ds);
#define DTRACE_DEVSTAT_DONE() \
if (dtrace_io_done_probe != NULL) \
(*dtrace_io_done_probe)(dtio_done_id, NULL, ds);
#define DTRACE_DEVSTAT_BIO_DONE() \
if (dtrace_io_done_probe != NULL) \
(*dtrace_io_done_probe)(dtio_done_id, bp, ds);
#define DTRACE_DEVSTAT_WAIT_START() \
if (dtrace_io_wait_start_probe != NULL) \
(*dtrace_io_wait_start_probe)(dtio_wait_start_id, NULL, ds);
#define DTRACE_DEVSTAT_WAIT_DONE() \
if (dtrace_io_wait_done_probe != NULL) \
(*dtrace_io_wait_done_probe)(dtio_wait_done_id, NULL, ds);
#else /* ! KDTRACE_HOOKS */
#define DTRACE_DEVSTAT_START()
#define DTRACE_DEVSTAT_DONE()
#define DTRACE_DEVSTAT_WAIT_START()
#define DTRACE_DEVSTAT_WAIT_DONE()
#endif /* KDTRACE_HOOKS */
static int devstat_num_devs;
static long devstat_generation = 1;
static int devstat_version = DEVSTAT_VERSION;
@ -227,6 +277,7 @@ devstat_start_transaction(struct devstat *ds, struct bintime *now)
}
ds->start_count++;
atomic_add_rel_int(&ds->sequence0, 1);
DTRACE_DEVSTAT_START();
}
void
@ -241,6 +292,7 @@ devstat_start_transaction_bio(struct devstat *ds, struct bio *bp)
binuptime(&bp->bio_t0);
devstat_start_transaction(ds, &bp->bio_t0);
DTRACE_DEVSTAT_BIO_START();
}
/*
@ -312,6 +364,7 @@ devstat_end_transaction(struct devstat *ds, uint32_t bytes,
ds->end_count++;
atomic_add_rel_int(&ds->sequence0, 1);
DTRACE_DEVSTAT_DONE();
}
void
@ -334,6 +387,7 @@ devstat_end_transaction_bio(struct devstat *ds, struct bio *bp)
devstat_end_transaction(ds, bp->bio_bcount - bp->bio_resid,
DEVSTAT_TAG_SIMPLE, flg, NULL, &bp->bio_t0);
DTRACE_DEVSTAT_BIO_DONE();
}
/*

1
sys/modules/dtrace/Makefile
View File

@ -9,6 +9,7 @@ SUBDIR= dtmalloc \
dtrace \
dtraceall \
dtrace_test \
dtio \
prototype \
sdt \
systrace

13
sys/modules/dtrace/dtio/Makefile Normal file
View File

@ -0,0 +1,13 @@
# $FreeBSD$
.PATH: ${.CURDIR}/../../../kern
KMOD= dtio
SRCS= dtio_kdtrace.c \
vnode_if.h
CFLAGS+= -I${.CURDIR}/../../../cddl/compat/opensolaris \
-I${.CURDIR}/../../../cddl/contrib/opensolaris/uts/common \
-I${.CURDIR}/../../..
.include <bsd.kmod.mk>

1
sys/modules/dtrace/dtraceall/dtraceall.c
View File

@ -65,6 +65,7 @@ MODULE_VERSION(dtraceall, 1);
MODULE_DEPEND(dtraceall, cyclic, 1, 1, 1);
MODULE_DEPEND(dtraceall, opensolaris, 1, 1, 1);
MODULE_DEPEND(dtraceall, dtrace, 1, 1, 1);
MODULE_DEPEND(dtraceall, dtio, 1, 1, 1);
MODULE_DEPEND(dtraceall, dtmalloc, 1, 1, 1);
MODULE_DEPEND(dtraceall, dtnfscl, 1, 1, 1);
MODULE_DEPEND(dtraceall, dtnfsclient, 1, 1, 1);

19
sys/sys/dtrace_bsd.h
View File

@ -38,6 +38,8 @@ struct thread;
struct vattr;
struct vnode;
struct reg;
struct devstat;
struct bio;
/*
* Cyclic clock function type definition used to hook the cyclic
@ -168,6 +170,23 @@ extern dtrace_nfsclient_nfs23_done_probe_func_t
extern dtrace_nfsclient_nfs23_done_probe_func_t
dtrace_nfscl_nfs234_done_probe;
/* IO Provider hooks, really hook into devstat */
typedef void (*dtrace_io_start_probe_func_t)(uint32_t, struct bio *,
struct devstat *);
extern dtrace_io_start_probe_func_t dtrace_io_start_probe;
typedef void (*dtrace_io_done_probe_func_t)(uint32_t, struct bio *,
struct devstat *);
extern dtrace_io_done_probe_func_t dtrace_io_done_probe;
typedef void (*dtrace_io_wait_start_probe_func_t)(uint32_t, uintptr_t *,
struct devstat *);
extern dtrace_io_wait_start_probe_func_t dtrace_io_wait_start_probe;
typedef void (*dtrace_io_wait_done_probe_func_t)(uint32_t, uintptr_t *,
struct devstat *);
extern dtrace_io_wait_done_probe_func_t dtrace_io_wait_done_probe;
/*
* Functions which allow the dtrace module to check that the kernel
* hooks have been compiled with sufficient space for it's private