1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include <sys/types.h> 30 #include <sys/param.h> 31 #include <sys/stat.h> 32 #include <sys/open.h> 33 #include <sys/file.h> 34 #include <sys/conf.h> 35 #include <sys/modctl.h> 36 #include <sys/cmn_err.h> 37 #include <sys/bitmap.h> 38 #include <sys/debug.h> 39 #include <sys/kmem.h> 40 #include <sys/errno.h> 41 #include <sys/sysmacros.h> 42 #include <sys/lockstat.h> 43 #include <sys/atomic.h> 44 #include <sys/dtrace.h> 45 46 #include <sys/ddi.h> 47 #include <sys/sunddi.h> 48 49 typedef struct lockstat_probe { 50 const char *lsp_func; 51 const char *lsp_name; 52 int lsp_probe; 53 dtrace_id_t lsp_id; 54 } lockstat_probe_t; 55 56 lockstat_probe_t lockstat_probes[] = 57 { 58 { LS_MUTEX_ENTER, LSA_ACQUIRE, LS_MUTEX_ENTER_ACQUIRE }, 59 { LS_MUTEX_ENTER, LSA_BLOCK, LS_MUTEX_ENTER_BLOCK }, 60 { LS_MUTEX_ENTER, LSA_SPIN, LS_MUTEX_ENTER_SPIN }, 61 { LS_MUTEX_EXIT, LSA_RELEASE, LS_MUTEX_EXIT_RELEASE }, 62 { LS_MUTEX_DESTROY, LSA_RELEASE, LS_MUTEX_DESTROY_RELEASE }, 63 { LS_MUTEX_TRYENTER, LSA_ACQUIRE, LS_MUTEX_TRYENTER_ACQUIRE }, 64 { LS_LOCK_SET, LSS_ACQUIRE, LS_LOCK_SET_ACQUIRE }, 65 { LS_LOCK_SET, LSS_SPIN, LS_LOCK_SET_SPIN }, 66 { LS_LOCK_SET_SPL, LSS_ACQUIRE, LS_LOCK_SET_SPL_ACQUIRE }, 67 { LS_LOCK_SET_SPL, LSS_SPIN, LS_LOCK_SET_SPL_SPIN }, 68 { LS_LOCK_TRY, LSS_ACQUIRE, LS_LOCK_TRY_ACQUIRE }, 69 { LS_LOCK_CLEAR, LSS_RELEASE, LS_LOCK_CLEAR_RELEASE }, 70 { LS_LOCK_CLEAR_SPLX, LSS_RELEASE, LS_LOCK_CLEAR_SPLX_RELEASE }, 71 { LS_CLOCK_UNLOCK, LSS_RELEASE, LS_CLOCK_UNLOCK_RELEASE }, 72 { LS_RW_ENTER, LSR_ACQUIRE, LS_RW_ENTER_ACQUIRE }, 73 { LS_RW_ENTER, LSR_BLOCK, LS_RW_ENTER_BLOCK }, 74 { LS_RW_EXIT, LSR_RELEASE, LS_RW_EXIT_RELEASE }, 75 { LS_RW_TRYENTER, LSR_ACQUIRE, LS_RW_TRYENTER_ACQUIRE }, 76 { LS_RW_TRYUPGRADE, LSR_UPGRADE, LS_RW_TRYUPGRADE_UPGRADE }, 77 { LS_RW_DOWNGRADE, LSR_DOWNGRADE, LS_RW_DOWNGRADE_DOWNGRADE }, 78 { LS_THREAD_LOCK, LST_SPIN, LS_THREAD_LOCK_SPIN }, 79 { LS_THREAD_LOCK_HIGH, LST_SPIN, LS_THREAD_LOCK_HIGH_SPIN }, 80 { NULL } 81 }; 82 83 static dev_info_t *lockstat_devi; /* saved in xxattach() for xxinfo() */ 84 static kmutex_t lockstat_test; /* for testing purposes only */ 85 static dtrace_provider_id_t lockstat_id; 86 87 /*ARGSUSED*/ 88 static void 89 lockstat_enable(void *arg, dtrace_id_t id, void *parg) 90 { 91 lockstat_probe_t *probe = parg; 92 93 ASSERT(!lockstat_probemap[probe->lsp_probe]); 94 95 lockstat_probemap[probe->lsp_probe] = id; 96 membar_producer(); 97 98 lockstat_probe = dtrace_probe; 99 membar_producer(); 100 101 lockstat_hot_patch(); 102 membar_producer(); 103 104 /* 105 * Immediately generate a record for the lockstat_test mutex 106 * to verify that the mutex hot-patch code worked as expected. 107 */ 108 mutex_enter(&lockstat_test); 109 mutex_exit(&lockstat_test); 110 } 111 112 /*ARGSUSED*/ 113 static void 114 lockstat_disable(void *arg, dtrace_id_t id, void *parg) 115 { 116 lockstat_probe_t *probe = parg; 117 int i; 118 119 ASSERT(lockstat_probemap[probe->lsp_probe]); 120 121 lockstat_probemap[probe->lsp_probe] = 0; 122 lockstat_hot_patch(); 123 membar_producer(); 124 125 /* 126 * See if we have any probes left enabled. 127 */ 128 for (i = 0; i < LS_NPROBES; i++) { 129 if (lockstat_probemap[i]) { 130 /* 131 * This probe is still enabled. We don't need to deal 132 * with waiting for all threads to be out of the 133 * lockstat critical sections; just return. 134 */ 135 return; 136 } 137 } 138 139 /* 140 * The delay() here isn't as cheesy as you might think. We don't 141 * want to busy-loop in the kernel, so we have to give up the 142 * CPU between calls to lockstat_active_threads(); that much is 143 * obvious. But the reason it's a do..while loop rather than a 144 * while loop is subtle. The memory barrier above guarantees that 145 * no threads will enter the lockstat code from this point forward. 146 * However, another thread could already be executing lockstat code 147 * without our knowledge if the update to its t_lockstat field hasn't 148 * cleared its CPU's store buffer. Delaying for one clock tick 149 * guarantees that either (1) the thread will have *ample* time to 150 * complete its work, or (2) the thread will be preempted, in which 151 * case it will have to grab and release a dispatcher lock, which 152 * will flush that CPU's store buffer. Either way we're covered. 153 */ 154 do { 155 delay(1); 156 } while (lockstat_active_threads()); 157 } 158 159 /*ARGSUSED*/ 160 static int 161 lockstat_open(dev_t *devp, int flag, int otyp, cred_t *cred_p) 162 { 163 return (0); 164 } 165 166 /* ARGSUSED */ 167 static int 168 lockstat_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result) 169 { 170 int error; 171 172 switch (infocmd) { 173 case DDI_INFO_DEVT2DEVINFO: 174 *result = (void *) lockstat_devi; 175 error = DDI_SUCCESS; 176 break; 177 case DDI_INFO_DEVT2INSTANCE: 178 *result = (void *)0; 179 error = DDI_SUCCESS; 180 break; 181 default: 182 error = DDI_FAILURE; 183 } 184 return (error); 185 } 186 187 /*ARGSUSED*/ 188 static void 189 lockstat_provide(void *arg, const dtrace_probedesc_t *desc) 190 { 191 int i = 0; 192 193 for (i = 0; lockstat_probes[i].lsp_func != NULL; i++) { 194 lockstat_probe_t *probe = &lockstat_probes[i]; 195 196 if (dtrace_probe_lookup(lockstat_id, "genunix", 197 probe->lsp_func, probe->lsp_name) != 0) 198 continue; 199 200 ASSERT(!probe->lsp_id); 201 probe->lsp_id = dtrace_probe_create(lockstat_id, 202 "genunix", probe->lsp_func, probe->lsp_name, 203 1, probe); 204 } 205 } 206 207 /*ARGSUSED*/ 208 static void 209 lockstat_destroy(void *arg, dtrace_id_t id, void *parg) 210 { 211 lockstat_probe_t *probe = parg; 212 213 ASSERT(!lockstat_probemap[probe->lsp_probe]); 214 probe->lsp_id = 0; 215 } 216 217 static dtrace_pattr_t lockstat_attr = { 218 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, 219 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, 220 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, 221 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, 222 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, 223 }; 224 225 static dtrace_pops_t lockstat_pops = { 226 lockstat_provide, 227 NULL, 228 lockstat_enable, 229 lockstat_disable, 230 NULL, 231 NULL, 232 NULL, 233 NULL, 234 NULL, 235 lockstat_destroy 236 }; 237 238 static int 239 lockstat_attach(dev_info_t *devi, ddi_attach_cmd_t cmd) 240 { 241 switch (cmd) { 242 case DDI_ATTACH: 243 break; 244 case DDI_RESUME: 245 return (DDI_SUCCESS); 246 default: 247 return (DDI_FAILURE); 248 } 249 250 if (ddi_create_minor_node(devi, "lockstat", S_IFCHR, 0, 251 DDI_PSEUDO, 0) == DDI_FAILURE || 252 dtrace_register("lockstat", &lockstat_attr, DTRACE_PRIV_KERNEL, 0, 253 &lockstat_pops, NULL, &lockstat_id) != 0) { 254 ddi_remove_minor_node(devi, NULL); 255 return (DDI_FAILURE); 256 } 257 258 ddi_report_dev(devi); 259 lockstat_devi = devi; 260 return (DDI_SUCCESS); 261 } 262 263 static int 264 lockstat_detach(dev_info_t *devi, ddi_detach_cmd_t cmd) 265 { 266 switch (cmd) { 267 case DDI_DETACH: 268 break; 269 case DDI_SUSPEND: 270 return (DDI_SUCCESS); 271 default: 272 return (DDI_FAILURE); 273 } 274 275 if (dtrace_unregister(lockstat_id) != 0) 276 return (DDI_FAILURE); 277 278 ddi_remove_minor_node(devi, NULL); 279 return (DDI_SUCCESS); 280 } 281 282 /* 283 * Configuration data structures 284 */ 285 static struct cb_ops lockstat_cb_ops = { 286 lockstat_open, /* open */ 287 nodev, /* close */ 288 nulldev, /* strategy */ 289 nulldev, /* print */ 290 nodev, /* dump */ 291 nodev, /* read */ 292 nodev, /* write */ 293 nodev, /* ioctl */ 294 nodev, /* devmap */ 295 nodev, /* mmap */ 296 nodev, /* segmap */ 297 nochpoll, /* poll */ 298 ddi_prop_op, /* cb_prop_op */ 299 0, /* streamtab */ 300 D_MP | D_NEW /* Driver compatibility flag */ 301 }; 302 303 static struct dev_ops lockstat_ops = { 304 DEVO_REV, /* devo_rev, */ 305 0, /* refcnt */ 306 lockstat_info, /* getinfo */ 307 nulldev, /* identify */ 308 nulldev, /* probe */ 309 lockstat_attach, /* attach */ 310 lockstat_detach, /* detach */ 311 nulldev, /* reset */ 312 &lockstat_cb_ops, /* cb_ops */ 313 NULL, /* bus_ops */ 314 }; 315 316 static struct modldrv modldrv = { 317 &mod_driverops, /* Type of module. This one is a driver */ 318 "Lock Statistics %I%", /* name of module */ 319 &lockstat_ops, /* driver ops */ 320 }; 321 322 static struct modlinkage modlinkage = { 323 MODREV_1, (void *)&modldrv, NULL 324 }; 325 326 int 327 _init(void) 328 { 329 return (mod_install(&modlinkage)); 330 } 331 332 int 333 _fini(void) 334 { 335 return (mod_remove(&modlinkage)); 336 } 337 338 int 339 _info(struct modinfo *modinfop) 340 { 341 return (mod_info(&modlinkage, modinfop)); 342 } 343