1 /*- 2 * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the author nor the names of any co-contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 /* 31 * This module holds the global variables and functions used to maintain 32 * lock_object structures. 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include "opt_ddb.h" 39 #include "opt_mprof.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/kernel.h> 44 #include <sys/ktr.h> 45 #include <sys/linker_set.h> 46 #include <sys/lock.h> 47 #include <sys/lock_profile.h> 48 #include <sys/malloc.h> 49 #include <sys/pcpu.h> 50 #include <sys/proc.h> 51 #include <sys/sbuf.h> 52 #include <sys/smp.h> 53 #include <sys/sysctl.h> 54 55 #ifdef DDB 56 #include <ddb/ddb.h> 57 #endif 58 59 #include <machine/cpufunc.h> 60 61 CTASSERT(LOCK_CLASS_MAX == 15); 62 63 struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = { 64 &lock_class_mtx_spin, 65 &lock_class_mtx_sleep, 66 &lock_class_sx, 67 &lock_class_rm, 68 &lock_class_rw, 69 &lock_class_lockmgr, 70 }; 71 72 void 73 lock_init(struct lock_object *lock, struct lock_class *class, const char *name, 74 const char *type, int flags) 75 { 76 int i; 77 78 /* Check for double-init and zero object. */ 79 KASSERT(!lock_initalized(lock), ("lock \"%s\" %p already initialized", 80 name, lock)); 81 82 /* Look up lock class to find its index. */ 83 for (i = 0; i < LOCK_CLASS_MAX; i++) 84 if (lock_classes[i] == class) { 85 lock->lo_flags = i << LO_CLASSSHIFT; 86 break; 87 } 88 KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class)); 89 90 /* Initialize the lock object. */ 91 lock->lo_name = name; 92 lock->lo_flags |= flags | LO_INITIALIZED; 93 LOCK_LOG_INIT(lock, 0); 94 WITNESS_INIT(lock, (type != NULL) ? type : name); 95 } 96 97 void 98 lock_destroy(struct lock_object *lock) 99 { 100 101 KASSERT(lock_initalized(lock), ("lock %p is not initialized", lock)); 102 WITNESS_DESTROY(lock); 103 LOCK_LOG_DESTROY(lock, 0); 104 lock->lo_flags &= ~LO_INITIALIZED; 105 } 106 107 #ifdef DDB 108 DB_SHOW_COMMAND(lock, db_show_lock) 109 { 110 struct lock_object *lock; 111 struct lock_class *class; 112 113 if (!have_addr) 114 return; 115 lock = (struct lock_object *)addr; 116 if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) { 117 db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock)); 118 return; 119 } 120 class = LOCK_CLASS(lock); 121 db_printf(" class: %s\n", class->lc_name); 122 db_printf(" name: %s\n", lock->lo_name); 123 class->lc_ddb_show(lock); 124 } 125 #endif 126 127 #ifdef LOCK_PROFILING 128 129 /* 130 * One object per-thread for each lock the thread owns. Tracks individual 131 * lock instances. 132 */ 133 struct lock_profile_object { 134 LIST_ENTRY(lock_profile_object) lpo_link; 135 struct lock_object *lpo_obj; 136 const char *lpo_file; 137 int lpo_line; 138 uint16_t lpo_ref; 139 uint16_t lpo_cnt; 140 u_int64_t lpo_acqtime; 141 u_int64_t lpo_waittime; 142 u_int lpo_contest_locking; 143 }; 144 145 /* 146 * One lock_prof for each (file, line, lock object) triple. 147 */ 148 struct lock_prof { 149 SLIST_ENTRY(lock_prof) link; 150 struct lock_class *class; 151 const char *file; 152 const char *name; 153 int line; 154 int ticks; 155 uintmax_t cnt_max; 156 uintmax_t cnt_tot; 157 uintmax_t cnt_wait; 158 uintmax_t cnt_cur; 159 uintmax_t cnt_contest_locking; 160 }; 161 162 SLIST_HEAD(lphead, lock_prof); 163 164 #define LPROF_HASH_SIZE 4096 165 #define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1) 166 #define LPROF_CACHE_SIZE 4096 167 168 /* 169 * Array of objects and profs for each type of object for each cpu. Spinlocks 170 * are handled seperately because a thread may be preempted and acquire a 171 * spinlock while in the lock profiling code of a non-spinlock. In this way 172 * we only need a critical section to protect the per-cpu lists. 173 */ 174 struct lock_prof_type { 175 struct lphead lpt_lpalloc; 176 struct lpohead lpt_lpoalloc; 177 struct lphead lpt_hash[LPROF_HASH_SIZE]; 178 struct lock_prof lpt_prof[LPROF_CACHE_SIZE]; 179 struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE]; 180 }; 181 182 struct lock_prof_cpu { 183 struct lock_prof_type lpc_types[2]; /* One for spin one for other. */ 184 }; 185 186 struct lock_prof_cpu *lp_cpu[MAXCPU]; 187 188 int lock_prof_enable = 0; 189 190 /* SWAG: sbuf size = avg stat. line size * number of locks */ 191 #define LPROF_SBUF_SIZE 256 * 400 192 193 static int lock_prof_rejected; 194 static int lock_prof_skipspin; 195 static int lock_prof_skipcount; 196 197 #ifndef USE_CPU_NANOSECONDS 198 u_int64_t 199 nanoseconds(void) 200 { 201 struct bintime bt; 202 u_int64_t ns; 203 204 binuptime(&bt); 205 /* From bintime2timespec */ 206 ns = bt.sec * (u_int64_t)1000000000; 207 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; 208 return (ns); 209 } 210 #endif 211 212 static void 213 lock_prof_init_type(struct lock_prof_type *type) 214 { 215 int i; 216 217 SLIST_INIT(&type->lpt_lpalloc); 218 LIST_INIT(&type->lpt_lpoalloc); 219 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 220 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], 221 link); 222 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], 223 lpo_link); 224 } 225 } 226 227 static void 228 lock_prof_init(void *arg) 229 { 230 int cpu; 231 232 for (cpu = 0; cpu <= mp_maxid; cpu++) { 233 lp_cpu[cpu] = malloc(sizeof(*lp_cpu[cpu]), M_DEVBUF, 234 M_WAITOK | M_ZERO); 235 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[0]); 236 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[1]); 237 } 238 } 239 SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); 240 241 static void 242 lock_prof_reset(void) 243 { 244 struct lock_prof_cpu *lpc; 245 int enabled, i, cpu; 246 247 enabled = lock_prof_enable; 248 lock_prof_enable = 0; 249 pause("lpreset", hz / 10); 250 for (cpu = 0; cpu <= mp_maxid; cpu++) { 251 lpc = lp_cpu[cpu]; 252 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 253 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 254 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 255 } 256 bzero(lpc, sizeof(*lpc)); 257 lock_prof_init_type(&lpc->lpc_types[0]); 258 lock_prof_init_type(&lpc->lpc_types[1]); 259 } 260 lock_prof_enable = enabled; 261 } 262 263 static void 264 lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 265 { 266 const char *p; 267 268 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 269 sbuf_printf(sb, 270 "%6ju %12ju %12ju %11ju %5ju %5ju %12ju %12ju %s:%d (%s:%s)\n", 271 lp->cnt_max / 1000, lp->cnt_tot / 1000, 272 lp->cnt_wait / 1000, lp->cnt_cur, 273 lp->cnt_cur == 0 ? (uintmax_t)0 : 274 lp->cnt_tot / (lp->cnt_cur * 1000), 275 lp->cnt_cur == 0 ? (uintmax_t)0 : 276 lp->cnt_wait / (lp->cnt_cur * 1000), 277 (uintmax_t)0, lp->cnt_contest_locking, 278 p, lp->line, lp->class->lc_name, lp->name); 279 } 280 281 static void 282 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 283 int spin, int t) 284 { 285 struct lock_prof_type *type; 286 struct lock_prof *l; 287 int cpu; 288 289 dst->file = match->file; 290 dst->line = match->line; 291 dst->class = match->class; 292 dst->name = match->name; 293 294 for (cpu = 0; cpu <= mp_maxid; cpu++) { 295 if (lp_cpu[cpu] == NULL) 296 continue; 297 type = &lp_cpu[cpu]->lpc_types[spin]; 298 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 299 if (l->ticks == t) 300 continue; 301 if (l->file != match->file || l->line != match->line || 302 l->name != match->name) 303 continue; 304 l->ticks = t; 305 if (l->cnt_max > dst->cnt_max) 306 dst->cnt_max = l->cnt_max; 307 dst->cnt_tot += l->cnt_tot; 308 dst->cnt_wait += l->cnt_wait; 309 dst->cnt_cur += l->cnt_cur; 310 dst->cnt_contest_locking += l->cnt_contest_locking; 311 } 312 } 313 314 } 315 316 static void 317 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 318 int t) 319 { 320 struct lock_prof *l; 321 int i; 322 323 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 324 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 325 struct lock_prof lp = {}; 326 327 if (l->ticks == t) 328 continue; 329 lock_prof_sum(l, &lp, i, spin, t); 330 lock_prof_output(&lp, sb); 331 if (sbuf_overflowed(sb)) 332 return; 333 } 334 } 335 } 336 337 static int 338 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 339 { 340 static int multiplier = 1; 341 struct sbuf *sb; 342 int error, cpu, t; 343 int enabled; 344 345 retry_sbufops: 346 sb = sbuf_new(NULL, NULL, LPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN); 347 sbuf_printf(sb, "\n%6s %12s %12s %11s %5s %5s %12s %12s %s\n", 348 "max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); 349 enabled = lock_prof_enable; 350 lock_prof_enable = 0; 351 pause("lpreset", hz / 10); 352 t = ticks; 353 for (cpu = 0; cpu <= mp_maxid; cpu++) { 354 if (lp_cpu[cpu] == NULL) 355 continue; 356 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[0], sb, 0, t); 357 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[1], sb, 1, t); 358 if (sbuf_overflowed(sb)) { 359 sbuf_delete(sb); 360 multiplier++; 361 goto retry_sbufops; 362 } 363 } 364 lock_prof_enable = enabled; 365 366 sbuf_finish(sb); 367 error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1); 368 sbuf_delete(sb); 369 return (error); 370 } 371 372 static int 373 enable_lock_prof(SYSCTL_HANDLER_ARGS) 374 { 375 int error, v; 376 377 v = lock_prof_enable; 378 error = sysctl_handle_int(oidp, &v, v, req); 379 if (error) 380 return (error); 381 if (req->newptr == NULL) 382 return (error); 383 if (v == lock_prof_enable) 384 return (0); 385 if (v == 1) 386 lock_prof_reset(); 387 lock_prof_enable = !!v; 388 389 return (0); 390 } 391 392 static int 393 reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) 394 { 395 int error, v; 396 397 v = 0; 398 error = sysctl_handle_int(oidp, &v, 0, req); 399 if (error) 400 return (error); 401 if (req->newptr == NULL) 402 return (error); 403 if (v == 0) 404 return (0); 405 lock_prof_reset(); 406 407 return (0); 408 } 409 410 static struct lock_prof * 411 lock_profile_lookup(struct lock_object *lo, int spin, const char *file, 412 int line) 413 { 414 const char *unknown = "(unknown)"; 415 struct lock_prof_type *type; 416 struct lock_prof *lp; 417 struct lphead *head; 418 const char *p; 419 u_int hash; 420 421 p = file; 422 if (p == NULL || *p == '\0') 423 p = unknown; 424 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; 425 hash &= LPROF_HASH_MASK; 426 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 427 head = &type->lpt_hash[hash]; 428 SLIST_FOREACH(lp, head, link) { 429 if (lp->line == line && lp->file == p && 430 lp->name == lo->lo_name) 431 return (lp); 432 433 } 434 lp = SLIST_FIRST(&type->lpt_lpalloc); 435 if (lp == NULL) { 436 lock_prof_rejected++; 437 return (lp); 438 } 439 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); 440 lp->file = p; 441 lp->line = line; 442 lp->class = LOCK_CLASS(lo); 443 lp->name = lo->lo_name; 444 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); 445 return (lp); 446 } 447 448 static struct lock_profile_object * 449 lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, 450 int line) 451 { 452 struct lock_profile_object *l; 453 struct lock_prof_type *type; 454 struct lpohead *head; 455 456 head = &curthread->td_lprof[spin]; 457 LIST_FOREACH(l, head, lpo_link) 458 if (l->lpo_obj == lo && l->lpo_file == file && 459 l->lpo_line == line) 460 return (l); 461 critical_enter(); 462 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 463 l = LIST_FIRST(&type->lpt_lpoalloc); 464 if (l == NULL) { 465 lock_prof_rejected++; 466 critical_exit(); 467 return (NULL); 468 } 469 LIST_REMOVE(l, lpo_link); 470 critical_exit(); 471 l->lpo_obj = lo; 472 l->lpo_file = file; 473 l->lpo_line = line; 474 l->lpo_cnt = 0; 475 LIST_INSERT_HEAD(head, l, lpo_link); 476 477 return (l); 478 } 479 480 void 481 lock_profile_obtain_lock_success(struct lock_object *lo, int contested, 482 uint64_t waittime, const char *file, int line) 483 { 484 static int lock_prof_count; 485 struct lock_profile_object *l; 486 int spin; 487 488 /* don't reset the timer when/if recursing */ 489 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 490 return; 491 if (lock_prof_skipcount && 492 (++lock_prof_count % lock_prof_skipcount) != 0) 493 return; 494 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 495 if (spin && lock_prof_skipspin == 1) 496 return; 497 l = lock_profile_object_lookup(lo, spin, file, line); 498 if (l == NULL) 499 return; 500 l->lpo_cnt++; 501 if (++l->lpo_ref > 1) 502 return; 503 l->lpo_contest_locking = contested; 504 l->lpo_acqtime = nanoseconds(); 505 if (waittime && (l->lpo_acqtime > waittime)) 506 l->lpo_waittime = l->lpo_acqtime - waittime; 507 else 508 l->lpo_waittime = 0; 509 } 510 511 void 512 lock_profile_release_lock(struct lock_object *lo) 513 { 514 struct lock_profile_object *l; 515 struct lock_prof_type *type; 516 struct lock_prof *lp; 517 u_int64_t holdtime; 518 struct lpohead *head; 519 int spin; 520 521 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 522 return; 523 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 524 head = &curthread->td_lprof[spin]; 525 critical_enter(); 526 LIST_FOREACH(l, head, lpo_link) 527 if (l->lpo_obj == lo) 528 break; 529 if (l == NULL) 530 goto out; 531 if (--l->lpo_ref > 0) 532 goto out; 533 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 534 if (lp == NULL) 535 goto release; 536 holdtime = nanoseconds() - l->lpo_acqtime; 537 if (holdtime < 0) 538 goto release; 539 /* 540 * Record if the lock has been held longer now than ever 541 * before. 542 */ 543 if (holdtime > lp->cnt_max) 544 lp->cnt_max = holdtime; 545 lp->cnt_tot += holdtime; 546 lp->cnt_wait += l->lpo_waittime; 547 lp->cnt_contest_locking += l->lpo_contest_locking; 548 lp->cnt_cur += l->lpo_cnt; 549 release: 550 LIST_REMOVE(l, lpo_link); 551 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 552 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 553 out: 554 critical_exit(); 555 } 556 557 SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging"); 558 SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, "lock profiling"); 559 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 560 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 561 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW, 562 &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions."); 563 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 564 &lock_prof_rejected, 0, "Number of rejected profiling records"); 565 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, 566 NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics"); 567 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, 568 NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics"); 569 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, 570 NULL, 0, enable_lock_prof, "I", "Enable lock profiling"); 571 572 #endif 573