freebsd-dev/sys/kern/dtio_kdtrace.c
George V. Neville-Neil 3fac94ba94 Initial commit of an I/O provider for DTrace on FreeBSD.
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
2012-07-11 16:27:02 +00:00

233 lines
6.0 KiB
C

/*-
* 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);