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 (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 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. 12 * 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] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 #include <sys/types.h> 29 #include <sys/param.h> 30 #include <sys/stat.h> 31 #include <sys/open.h> 32 #include <sys/file.h> 33 #include <sys/conf.h> 34 #include <sys/modctl.h> 35 #include <sys/cmn_err.h> 36 #include <sys/bitmap.h> 37 #include <sys/debug.h> 38 #include <sys/kmem.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> 44 45 #include <sys/ddi.h> 46 #include <sys/sunddi.h> 47 48 typedef struct lockstat_probe { 49 const char *lsp_func; 50 const char *lsp_name; 51 int lsp_probe; 52 dtrace_id_t lsp_id; 53 } lockstat_probe_t; 54 55 lockstat_probe_t lockstat_probes[] = 56 { 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 }, 79 { NULL } 80 }; 81 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; 85 86 /*ARGSUSED*/ 87 static void 88 lockstat_enable(void *arg, dtrace_id_t id, void *parg) 89 { 90 lockstat_probe_t *probe = parg; 91 92 ASSERT(!lockstat_probemap[probe->lsp_probe]); 93 94 lockstat_probemap[probe->lsp_probe] = id; 95 membar_producer(); 96 97 lockstat_hot_patch(); 98 membar_producer(); 99 100 /* 101 * Immediately generate a record for the lockstat_test mutex 102 * to verify that the mutex hot-patch code worked as expected. 103 */ 104 mutex_enter(&lockstat_test); 105 mutex_exit(&lockstat_test); 106 } 107 108 /*ARGSUSED*/ 109 static void 110 lockstat_disable(void *arg, dtrace_id_t id, void *parg) 111 { 112 lockstat_probe_t *probe = parg; 113 int i; 114 115 ASSERT(lockstat_probemap[probe->lsp_probe]); 116 117 lockstat_probemap[probe->lsp_probe] = 0; 118 lockstat_hot_patch(); 119 membar_producer(); 120 121 /* 122 * See if we have any probes left enabled. 123 */ 124 for (i = 0; i < LS_NPROBES; i++) { 125 if (lockstat_probemap[i]) { 126 /* 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. 130 */ 131 return; 132 } 133 } 134 135 /* 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. 149 */ 150 do { 151 delay(1); 152 } while (lockstat_active_threads()); 153 } 154 155 /*ARGSUSED*/ 156 static int 157 lockstat_open(dev_t *devp, int flag, int otyp, cred_t *cred_p) 158 { 159 return (0); 160 } 161 162 /* ARGSUSED */ 163 static int 164 lockstat_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result) 165 { 166 int error; 167 168 switch (infocmd) { 169 case DDI_INFO_DEVT2DEVINFO: 170 *result = (void *) lockstat_devi; 171 error = DDI_SUCCESS; 172 break; 173 case DDI_INFO_DEVT2INSTANCE: 174 *result = (void *)0; 175 error = DDI_SUCCESS; 176 break; 177 default: 178 error = DDI_FAILURE; 179 } 180 return (error); 181 } 182 183 /*ARGSUSED*/ 184 static void 185 lockstat_provide(void *arg, const dtrace_probedesc_t *desc) 186 { 187 int i = 0; 188 189 for (i = 0; lockstat_probes[i].lsp_func != NULL; i++) { 190 lockstat_probe_t *probe = &lockstat_probes[i]; 191 192 if (dtrace_probe_lookup(lockstat_id, "genunix", 193 probe->lsp_func, probe->lsp_name) != 0) 194 continue; 195 196 ASSERT(!probe->lsp_id); 197 probe->lsp_id = dtrace_probe_create(lockstat_id, 198 "genunix", probe->lsp_func, probe->lsp_name, 199 1, probe); 200 } 201 } 202 203 /*ARGSUSED*/ 204 static void 205 lockstat_destroy(void *arg, dtrace_id_t id, void *parg) 206 { 207 lockstat_probe_t *probe = parg; 208 209 ASSERT(!lockstat_probemap[probe->lsp_probe]); 210 probe->lsp_id = 0; 211 } 212 213 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 }, 219 }; 220 221 static dtrace_pops_t lockstat_pops = { 222 lockstat_provide, 223 NULL, 224 lockstat_enable, 225 lockstat_disable, 226 NULL, 227 NULL, 228 NULL, 229 NULL, 230 NULL, 231 lockstat_destroy 232 }; 233 234 static int 235 lockstat_attach(dev_info_t *devi, ddi_attach_cmd_t cmd) 236 { 237 switch (cmd) { 238 case DDI_ATTACH: 239 break; 240 case DDI_RESUME: 241 return (DDI_SUCCESS); 242 default: 243 return (DDI_FAILURE); 244 } 245 246 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); 252 } 253 254 lockstat_probe = dtrace_probe; 255 membar_producer(); 256 257 ddi_report_dev(devi); 258 lockstat_devi = devi; 259 return (DDI_SUCCESS); 260 } 261 262 static int 263 lockstat_detach(dev_info_t *devi, ddi_detach_cmd_t cmd) 264 { 265 switch (cmd) { 266 case DDI_DETACH: 267 break; 268 case DDI_SUSPEND: 269 return (DDI_SUCCESS); 270 default: 271 return (DDI_FAILURE); 272 } 273 274 if (dtrace_unregister(lockstat_id) != 0) 275 return (DDI_FAILURE); 276 277 ddi_remove_minor_node(devi, NULL); 278 return (DDI_SUCCESS); 279 } 280 281 /* 282 * Configuration data structures 283 */ 284 static struct cb_ops lockstat_cb_ops = { 285 lockstat_open, /* open */ 286 nodev, /* close */ 287 nulldev, /* strategy */ 288 nulldev, /* print */ 289 nodev, /* dump */ 290 nodev, /* read */ 291 nodev, /* write */ 292 nodev, /* ioctl */ 293 nodev, /* devmap */ 294 nodev, /* mmap */ 295 nodev, /* segmap */ 296 nochpoll, /* poll */ 297 ddi_prop_op, /* cb_prop_op */ 298 0, /* streamtab */ 299 D_MP | D_NEW /* Driver compatibility flag */ 300 }; 301 302 static struct dev_ops lockstat_ops = { 303 DEVO_REV, /* devo_rev, */ 304 0, /* refcnt */ 305 lockstat_info, /* getinfo */ 306 nulldev, /* identify */ 307 nulldev, /* probe */ 308 lockstat_attach, /* attach */ 309 lockstat_detach, /* detach */ 310 nulldev, /* reset */ 311 &lockstat_cb_ops, /* cb_ops */ 312 NULL, /* bus_ops */ 313 }; 314 315 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 */ 319 }; 320 321 static struct modlinkage modlinkage = { 322 MODREV_1, (void *)&modldrv, NULL 323 }; 324 325 int 326 _init(void) 327 { 328 return (mod_install(&modlinkage)); 329 } 330 331 int 332 _fini(void) 333 { 334 return (mod_remove(&modlinkage)); 335 } 336 337 int 338 _info(struct modinfo *modinfop) 339 { 340 return (mod_info(&modlinkage, modinfop)); 341 } 342