OpenSolaris_b135/uts/common/dtrace/lockstat.c
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/open.h>
#include <sys/file.h>
#include <sys/conf.h>
#include <sys/modctl.h>
#include <sys/cmn_err.h>
#include <sys/bitmap.h>
#include <sys/debug.h>
#include <sys/kmem.h>
#include <sys/errno.h>
#include <sys/sysmacros.h>
#include <sys/lockstat.h>
#include <sys/atomic.h>
#include <sys/dtrace.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
typedef struct lockstat_probe {
const char *lsp_func;
const char *lsp_name;
int lsp_probe;
dtrace_id_t lsp_id;
} lockstat_probe_t;
lockstat_probe_t lockstat_probes[] =
{
{ LS_MUTEX_ENTER, LSA_ACQUIRE, LS_MUTEX_ENTER_ACQUIRE },
{ LS_MUTEX_ENTER, LSA_BLOCK, LS_MUTEX_ENTER_BLOCK },
{ LS_MUTEX_ENTER, LSA_SPIN, LS_MUTEX_ENTER_SPIN },
{ LS_MUTEX_EXIT, LSA_RELEASE, LS_MUTEX_EXIT_RELEASE },
{ LS_MUTEX_DESTROY, LSA_RELEASE, LS_MUTEX_DESTROY_RELEASE },
{ LS_MUTEX_TRYENTER, LSA_ACQUIRE, LS_MUTEX_TRYENTER_ACQUIRE },
{ LS_LOCK_SET, LSS_ACQUIRE, LS_LOCK_SET_ACQUIRE },
{ LS_LOCK_SET, LSS_SPIN, LS_LOCK_SET_SPIN },
{ LS_LOCK_SET_SPL, LSS_ACQUIRE, LS_LOCK_SET_SPL_ACQUIRE },
{ LS_LOCK_SET_SPL, LSS_SPIN, LS_LOCK_SET_SPL_SPIN },
{ LS_LOCK_TRY, LSS_ACQUIRE, LS_LOCK_TRY_ACQUIRE },
{ LS_LOCK_CLEAR, LSS_RELEASE, LS_LOCK_CLEAR_RELEASE },
{ LS_LOCK_CLEAR_SPLX, LSS_RELEASE, LS_LOCK_CLEAR_SPLX_RELEASE },
{ LS_CLOCK_UNLOCK, LSS_RELEASE, LS_CLOCK_UNLOCK_RELEASE },
{ LS_RW_ENTER, LSR_ACQUIRE, LS_RW_ENTER_ACQUIRE },
{ LS_RW_ENTER, LSR_BLOCK, LS_RW_ENTER_BLOCK },
{ LS_RW_EXIT, LSR_RELEASE, LS_RW_EXIT_RELEASE },
{ LS_RW_TRYENTER, LSR_ACQUIRE, LS_RW_TRYENTER_ACQUIRE },
{ LS_RW_TRYUPGRADE, LSR_UPGRADE, LS_RW_TRYUPGRADE_UPGRADE },
{ LS_RW_DOWNGRADE, LSR_DOWNGRADE, LS_RW_DOWNGRADE_DOWNGRADE },
{ LS_THREAD_LOCK, LST_SPIN, LS_THREAD_LOCK_SPIN },
{ LS_THREAD_LOCK_HIGH, LST_SPIN, LS_THREAD_LOCK_HIGH_SPIN },
{ NULL }
};
static dev_info_t *lockstat_devi; /* saved in xxattach() for xxinfo() */
static kmutex_t lockstat_test; /* for testing purposes only */
static dtrace_provider_id_t lockstat_id;
/*ARGSUSED*/
static int
lockstat_enable(void *arg, dtrace_id_t id, void *parg)
{
lockstat_probe_t *probe = parg;
ASSERT(!lockstat_probemap[probe->lsp_probe]);
lockstat_probemap[probe->lsp_probe] = id;
membar_producer();
lockstat_hot_patch();
membar_producer();
/*
* Immediately generate a record for the lockstat_test mutex
* to verify that the mutex hot-patch code worked as expected.
*/
mutex_enter(&lockstat_test);
mutex_exit(&lockstat_test);
return (0);
}
/*ARGSUSED*/
static void
lockstat_disable(void *arg, dtrace_id_t id, void *parg)
{
lockstat_probe_t *probe = parg;
int i;
ASSERT(lockstat_probemap[probe->lsp_probe]);
lockstat_probemap[probe->lsp_probe] = 0;
lockstat_hot_patch();
membar_producer();
/*
* See if we have any probes left enabled.
*/
for (i = 0; i < LS_NPROBES; i++) {
if (lockstat_probemap[i]) {
/*
* This probe is still enabled. We don't need to deal
* with waiting for all threads to be out of the
* lockstat critical sections; just return.
*/
return;
}
}
/*
* The delay() here isn't as cheesy as you might think. We don't
* want to busy-loop in the kernel, so we have to give up the
* CPU between calls to lockstat_active_threads(); that much is
* obvious. But the reason it's a do..while loop rather than a
* while loop is subtle. The memory barrier above guarantees that
* no threads will enter the lockstat code from this point forward.
* However, another thread could already be executing lockstat code
* without our knowledge if the update to its t_lockstat field hasn't
* cleared its CPU's store buffer. Delaying for one clock tick
* guarantees that either (1) the thread will have *ample* time to
* complete its work, or (2) the thread will be preempted, in which
* case it will have to grab and release a dispatcher lock, which
* will flush that CPU's store buffer. Either way we're covered.
*/
do {
delay(1);
} while (lockstat_active_threads());
}
/*ARGSUSED*/
static int
lockstat_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
{
return (0);
}
/* ARGSUSED */
static int
lockstat_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
{
int error;
switch (infocmd) {
case DDI_INFO_DEVT2DEVINFO:
*result = (void *) lockstat_devi;
error = DDI_SUCCESS;
break;
case DDI_INFO_DEVT2INSTANCE:
*result = (void *)0;
error = DDI_SUCCESS;
break;
default:
error = DDI_FAILURE;
}
return (error);
}
/*ARGSUSED*/
static void
lockstat_provide(void *arg, const dtrace_probedesc_t *desc)
{
int i = 0;
for (i = 0; lockstat_probes[i].lsp_func != NULL; i++) {
lockstat_probe_t *probe = &lockstat_probes[i];
if (dtrace_probe_lookup(lockstat_id, "genunix",
probe->lsp_func, probe->lsp_name) != 0)
continue;
ASSERT(!probe->lsp_id);
probe->lsp_id = dtrace_probe_create(lockstat_id,
"genunix", probe->lsp_func, probe->lsp_name,
1, probe);
}
}
/*ARGSUSED*/
static void
lockstat_destroy(void *arg, dtrace_id_t id, void *parg)
{
lockstat_probe_t *probe = parg;
ASSERT(!lockstat_probemap[probe->lsp_probe]);
probe->lsp_id = 0;
}
static dtrace_pattr_t lockstat_attr = {
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
};
static dtrace_pops_t lockstat_pops = {
lockstat_provide,
NULL,
lockstat_enable,
lockstat_disable,
NULL,
NULL,
NULL,
NULL,
NULL,
lockstat_destroy
};
static int
lockstat_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
switch (cmd) {
case DDI_ATTACH:
break;
case DDI_RESUME:
return (DDI_SUCCESS);
default:
return (DDI_FAILURE);
}
if (ddi_create_minor_node(devi, "lockstat", S_IFCHR, 0,
DDI_PSEUDO, 0) == DDI_FAILURE ||
dtrace_register("lockstat", &lockstat_attr, DTRACE_PRIV_KERNEL,
NULL, &lockstat_pops, NULL, &lockstat_id) != 0) {
ddi_remove_minor_node(devi, NULL);
return (DDI_FAILURE);
}
lockstat_probe = dtrace_probe;
membar_producer();
ddi_report_dev(devi);
lockstat_devi = devi;
return (DDI_SUCCESS);
}
static int
lockstat_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
switch (cmd) {
case DDI_DETACH:
break;
case DDI_SUSPEND:
return (DDI_SUCCESS);
default:
return (DDI_FAILURE);
}
if (dtrace_unregister(lockstat_id) != 0)
return (DDI_FAILURE);
ddi_remove_minor_node(devi, NULL);
return (DDI_SUCCESS);
}
/*
* Configuration data structures
*/
static struct cb_ops lockstat_cb_ops = {
lockstat_open, /* open */
nodev, /* close */
nulldev, /* strategy */
nulldev, /* print */
nodev, /* dump */
nodev, /* read */
nodev, /* write */
nodev, /* ioctl */
nodev, /* devmap */
nodev, /* mmap */
nodev, /* segmap */
nochpoll, /* poll */
ddi_prop_op, /* cb_prop_op */
0, /* streamtab */
D_MP | D_NEW /* Driver compatibility flag */
};
static struct dev_ops lockstat_ops = {
DEVO_REV, /* devo_rev, */
0, /* refcnt */
lockstat_info, /* getinfo */
nulldev, /* identify */
nulldev, /* probe */
lockstat_attach, /* attach */
lockstat_detach, /* detach */
nulldev, /* reset */
&lockstat_cb_ops, /* cb_ops */
NULL, /* bus_ops */
NULL, /* power */
ddi_quiesce_not_needed, /* quiesce */
};
static struct modldrv modldrv = {
&mod_driverops, /* Type of module. This one is a driver */
"Lock Statistics", /* name of module */
&lockstat_ops, /* driver ops */
};
static struct modlinkage modlinkage = {
MODREV_1, (void *)&modldrv, NULL
};
int
_init(void)
{
return (mod_install(&modlinkage));
}
int
_fini(void)
{
return (mod_remove(&modlinkage));
}
int
_info(struct modinfo *modinfop)
{
return (mod_info(&modlinkage, modinfop));
}