4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
26 #pragma ident "%Z%%M% %I% %E% SMI"
28 #include <sys/types.h>
29 #include <sys/param.h>
34 #include <sys/modctl.h>
35 #include <sys/cmn_err.h>
36 #include <sys/bitmap.h>
37 #include <sys/debug.h>
39 #include <sys/errno.h>
40 #include <sys/sysmacros.h>
41 #include <sys/lockstat.h>
42 #include <sys/atomic.h>
43 #include <sys/dtrace.h>
46 #include <sys/sunddi.h>
48 typedef struct lockstat_probe {
55 lockstat_probe_t lockstat_probes[] =
57 { LS_MUTEX_ENTER, LSA_ACQUIRE, LS_MUTEX_ENTER_ACQUIRE },
58 { LS_MUTEX_ENTER, LSA_BLOCK, LS_MUTEX_ENTER_BLOCK },
59 { LS_MUTEX_ENTER, LSA_SPIN, LS_MUTEX_ENTER_SPIN },
60 { LS_MUTEX_EXIT, LSA_RELEASE, LS_MUTEX_EXIT_RELEASE },
61 { LS_MUTEX_DESTROY, LSA_RELEASE, LS_MUTEX_DESTROY_RELEASE },
62 { LS_MUTEX_TRYENTER, LSA_ACQUIRE, LS_MUTEX_TRYENTER_ACQUIRE },
63 { LS_LOCK_SET, LSS_ACQUIRE, LS_LOCK_SET_ACQUIRE },
64 { LS_LOCK_SET, LSS_SPIN, LS_LOCK_SET_SPIN },
65 { LS_LOCK_SET_SPL, LSS_ACQUIRE, LS_LOCK_SET_SPL_ACQUIRE },
66 { LS_LOCK_SET_SPL, LSS_SPIN, LS_LOCK_SET_SPL_SPIN },
67 { LS_LOCK_TRY, LSS_ACQUIRE, LS_LOCK_TRY_ACQUIRE },
68 { LS_LOCK_CLEAR, LSS_RELEASE, LS_LOCK_CLEAR_RELEASE },
69 { LS_LOCK_CLEAR_SPLX, LSS_RELEASE, LS_LOCK_CLEAR_SPLX_RELEASE },
70 { LS_CLOCK_UNLOCK, LSS_RELEASE, LS_CLOCK_UNLOCK_RELEASE },
71 { LS_RW_ENTER, LSR_ACQUIRE, LS_RW_ENTER_ACQUIRE },
72 { LS_RW_ENTER, LSR_BLOCK, LS_RW_ENTER_BLOCK },
73 { LS_RW_EXIT, LSR_RELEASE, LS_RW_EXIT_RELEASE },
74 { LS_RW_TRYENTER, LSR_ACQUIRE, LS_RW_TRYENTER_ACQUIRE },
75 { LS_RW_TRYUPGRADE, LSR_UPGRADE, LS_RW_TRYUPGRADE_UPGRADE },
76 { LS_RW_DOWNGRADE, LSR_DOWNGRADE, LS_RW_DOWNGRADE_DOWNGRADE },
77 { LS_THREAD_LOCK, LST_SPIN, LS_THREAD_LOCK_SPIN },
78 { LS_THREAD_LOCK_HIGH, LST_SPIN, LS_THREAD_LOCK_HIGH_SPIN },
82 static dev_info_t *lockstat_devi; /* saved in xxattach() for xxinfo() */
83 static kmutex_t lockstat_test; /* for testing purposes only */
84 static dtrace_provider_id_t lockstat_id;
88 lockstat_enable(void *arg, dtrace_id_t id, void *parg)
90 lockstat_probe_t *probe = parg;
92 ASSERT(!lockstat_probemap[probe->lsp_probe]);
94 lockstat_probemap[probe->lsp_probe] = id;
101 * Immediately generate a record for the lockstat_test mutex
102 * to verify that the mutex hot-patch code worked as expected.
104 mutex_enter(&lockstat_test);
105 mutex_exit(&lockstat_test);
110 lockstat_disable(void *arg, dtrace_id_t id, void *parg)
112 lockstat_probe_t *probe = parg;
115 ASSERT(lockstat_probemap[probe->lsp_probe]);
117 lockstat_probemap[probe->lsp_probe] = 0;
118 lockstat_hot_patch();
122 * See if we have any probes left enabled.
124 for (i = 0; i < LS_NPROBES; i++) {
125 if (lockstat_probemap[i]) {
127 * This probe is still enabled. We don't need to deal
128 * with waiting for all threads to be out of the
129 * lockstat critical sections; just return.
136 * The delay() here isn't as cheesy as you might think. We don't
137 * want to busy-loop in the kernel, so we have to give up the
138 * CPU between calls to lockstat_active_threads(); that much is
139 * obvious. But the reason it's a do..while loop rather than a
140 * while loop is subtle. The memory barrier above guarantees that
141 * no threads will enter the lockstat code from this point forward.
142 * However, another thread could already be executing lockstat code
143 * without our knowledge if the update to its t_lockstat field hasn't
144 * cleared its CPU's store buffer. Delaying for one clock tick
145 * guarantees that either (1) the thread will have *ample* time to
146 * complete its work, or (2) the thread will be preempted, in which
147 * case it will have to grab and release a dispatcher lock, which
148 * will flush that CPU's store buffer. Either way we're covered.
152 } while (lockstat_active_threads());
157 lockstat_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
164 lockstat_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
169 case DDI_INFO_DEVT2DEVINFO:
170 *result = (void *) lockstat_devi;
173 case DDI_INFO_DEVT2INSTANCE:
185 lockstat_provide(void *arg, const dtrace_probedesc_t *desc)
189 for (i = 0; lockstat_probes[i].lsp_func != NULL; i++) {
190 lockstat_probe_t *probe = &lockstat_probes[i];
192 if (dtrace_probe_lookup(lockstat_id, "genunix",
193 probe->lsp_func, probe->lsp_name) != 0)
196 ASSERT(!probe->lsp_id);
197 probe->lsp_id = dtrace_probe_create(lockstat_id,
198 "genunix", probe->lsp_func, probe->lsp_name,
205 lockstat_destroy(void *arg, dtrace_id_t id, void *parg)
207 lockstat_probe_t *probe = parg;
209 ASSERT(!lockstat_probemap[probe->lsp_probe]);
213 static dtrace_pattr_t lockstat_attr = {
214 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
215 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
216 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
217 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
218 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
221 static dtrace_pops_t lockstat_pops = {
235 lockstat_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
241 return (DDI_SUCCESS);
243 return (DDI_FAILURE);
246 if (ddi_create_minor_node(devi, "lockstat", S_IFCHR, 0,
247 DDI_PSEUDO, 0) == DDI_FAILURE ||
248 dtrace_register("lockstat", &lockstat_attr, DTRACE_PRIV_KERNEL,
249 NULL, &lockstat_pops, NULL, &lockstat_id) != 0) {
250 ddi_remove_minor_node(devi, NULL);
251 return (DDI_FAILURE);
254 lockstat_probe = dtrace_probe;
257 ddi_report_dev(devi);
258 lockstat_devi = devi;
259 return (DDI_SUCCESS);
263 lockstat_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
269 return (DDI_SUCCESS);
271 return (DDI_FAILURE);
274 if (dtrace_unregister(lockstat_id) != 0)
275 return (DDI_FAILURE);
277 ddi_remove_minor_node(devi, NULL);
278 return (DDI_SUCCESS);
282 * Configuration data structures
284 static struct cb_ops lockstat_cb_ops = {
285 lockstat_open, /* open */
287 nulldev, /* strategy */
297 ddi_prop_op, /* cb_prop_op */
299 D_MP | D_NEW /* Driver compatibility flag */
302 static struct dev_ops lockstat_ops = {
303 DEVO_REV, /* devo_rev, */
305 lockstat_info, /* getinfo */
306 nulldev, /* identify */
308 lockstat_attach, /* attach */
309 lockstat_detach, /* detach */
311 &lockstat_cb_ops, /* cb_ops */
315 static struct modldrv modldrv = {
316 &mod_driverops, /* Type of module. This one is a driver */
317 "Lock Statistics %I%", /* name of module */
318 &lockstat_ops, /* driver ops */
321 static struct modlinkage modlinkage = {
322 MODREV_1, (void *)&modldrv, NULL
328 return (mod_install(&modlinkage));
334 return (mod_remove(&modlinkage));
338 _info(struct modinfo *modinfop)
340 return (mod_info(&modlinkage, modinfop));