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