Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_lock.c
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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 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 /* 28 * This module holds the global variables and functions used to maintain 29 * lock_object structures. 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD: releng/11.0/sys/kern/subr_lock.c 303953 2016-08-11 09:28:49Z mjg $"); 34 35 #include "opt_ddb.h" 36 #include "opt_mprof.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/kernel.h> 41 #include <sys/ktr.h> 42 #include <sys/lock.h> 43 #include <sys/lock_profile.h> 44 #include <sys/malloc.h> 45 #include <sys/mutex.h> 46 #include <sys/pcpu.h> 47 #include <sys/proc.h> 48 #include <sys/sbuf.h> 49 #include <sys/sched.h> 50 #include <sys/smp.h> 51 #include <sys/sysctl.h> 52 53 #ifdef DDB 54 #include <ddb/ddb.h> 55 #endif 56 57 #include <machine/cpufunc.h> 58 59 CTASSERT(LOCK_CLASS_MAX == 15); 60 61 struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = { 62 &lock_class_mtx_spin, 63 &lock_class_mtx_sleep, 64 &lock_class_sx, 65 &lock_class_rm, 66 &lock_class_rm_sleepable, 67 &lock_class_rw, 68 &lock_class_lockmgr, 69 }; 70 71 void 72 lock_init(struct lock_object *lock, struct lock_class *class, const char *name, 73 const char *type, int flags) 74 { 75 int i; 76 77 /* Check for double-init and zero object. */ 78 KASSERT(flags & LO_NEW || !lock_initialized(lock), 79 ("lock \"%s\" %p already initialized", name, lock)); 80 81 /* Look up lock class to find its index. */ 82 for (i = 0; i < LOCK_CLASS_MAX; i++) 83 if (lock_classes[i] == class) { 84 lock->lo_flags = i << LO_CLASSSHIFT; 85 break; 86 } 87 KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class)); 88 89 /* Initialize the lock object. */ 90 lock->lo_name = name; 91 lock->lo_flags |= flags | LO_INITIALIZED; 92 LOCK_LOG_INIT(lock, 0); 93 WITNESS_INIT(lock, (type != NULL) ? type : name); 94 } 95 96 void 97 lock_destroy(struct lock_object *lock) 98 { 99 100 KASSERT(lock_initialized(lock), ("lock %p is not initialized", lock)); 101 WITNESS_DESTROY(lock); 102 LOCK_LOG_DESTROY(lock, 0); 103 lock->lo_flags &= ~LO_INITIALIZED; 104 } 105 106 void 107 lock_delay(struct lock_delay_arg *la) 108 { 109 u_int i, delay, backoff, min, max; 110 struct lock_delay_config *lc = la->config; 111 112 delay = la->delay; 113 114 if (delay == 0) 115 delay = lc->initial; 116 else { 117 delay += lc->step; 118 max = lc->max; 119 if (delay > max) 120 delay = max; 121 } 122 123 backoff = cpu_ticks() % delay; 124 min = lc->min; 125 if (backoff < min) 126 backoff = min; 127 for (i = 0; i < backoff; i++) 128 cpu_spinwait(); 129 130 la->delay = delay; 131 la->spin_cnt += backoff; 132 } 133 134 #ifdef DDB 135 DB_SHOW_COMMAND(lock, db_show_lock) 136 { 137 struct lock_object *lock; 138 struct lock_class *class; 139 140 if (!have_addr) 141 return; 142 lock = (struct lock_object *)addr; 143 if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) { 144 db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock)); 145 return; 146 } 147 class = LOCK_CLASS(lock); 148 db_printf(" class: %s\n", class->lc_name); 149 db_printf(" name: %s\n", lock->lo_name); 150 class->lc_ddb_show(lock); 151 } 152 #endif 153 154 #ifdef LOCK_PROFILING 155 156 /* 157 * One object per-thread for each lock the thread owns. Tracks individual 158 * lock instances. 159 */ 160 struct lock_profile_object { 161 LIST_ENTRY(lock_profile_object) lpo_link; 162 struct lock_object *lpo_obj; 163 const char *lpo_file; 164 int lpo_line; 165 uint16_t lpo_ref; 166 uint16_t lpo_cnt; 167 uint64_t lpo_acqtime; 168 uint64_t lpo_waittime; 169 u_int lpo_contest_locking; 170 }; 171 172 /* 173 * One lock_prof for each (file, line, lock object) triple. 174 */ 175 struct lock_prof { 176 SLIST_ENTRY(lock_prof) link; 177 struct lock_class *class; 178 const char *file; 179 const char *name; 180 int line; 181 int ticks; 182 uintmax_t cnt_wait_max; 183 uintmax_t cnt_max; 184 uintmax_t cnt_tot; 185 uintmax_t cnt_wait; 186 uintmax_t cnt_cur; 187 uintmax_t cnt_contest_locking; 188 }; 189 190 SLIST_HEAD(lphead, lock_prof); 191 192 #define LPROF_HASH_SIZE 4096 193 #define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1) 194 #define LPROF_CACHE_SIZE 4096 195 196 /* 197 * Array of objects and profs for each type of object for each cpu. Spinlocks 198 * are handled separately because a thread may be preempted and acquire a 199 * spinlock while in the lock profiling code of a non-spinlock. In this way 200 * we only need a critical section to protect the per-cpu lists. 201 */ 202 struct lock_prof_type { 203 struct lphead lpt_lpalloc; 204 struct lpohead lpt_lpoalloc; 205 struct lphead lpt_hash[LPROF_HASH_SIZE]; 206 struct lock_prof lpt_prof[LPROF_CACHE_SIZE]; 207 struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE]; 208 }; 209 210 struct lock_prof_cpu { 211 struct lock_prof_type lpc_types[2]; /* One for spin one for other. */ 212 }; 213 214 struct lock_prof_cpu *lp_cpu[MAXCPU]; 215 216 volatile int lock_prof_enable = 0; 217 static volatile int lock_prof_resetting; 218 219 #define LPROF_SBUF_SIZE 256 220 221 static int lock_prof_rejected; 222 static int lock_prof_skipspin; 223 static int lock_prof_skipcount; 224 225 #ifndef USE_CPU_NANOSECONDS 226 uint64_t 227 nanoseconds(void) 228 { 229 struct bintime bt; 230 uint64_t ns; 231 232 binuptime(&bt); 233 /* From bintime2timespec */ 234 ns = bt.sec * (uint64_t)1000000000; 235 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; 236 return (ns); 237 } 238 #endif 239 240 static void 241 lock_prof_init_type(struct lock_prof_type *type) 242 { 243 int i; 244 245 SLIST_INIT(&type->lpt_lpalloc); 246 LIST_INIT(&type->lpt_lpoalloc); 247 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 248 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], 249 link); 250 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], 251 lpo_link); 252 } 253 } 254 255 static void 256 lock_prof_init(void *arg) 257 { 258 int cpu; 259 260 for (cpu = 0; cpu <= mp_maxid; cpu++) { 261 lp_cpu[cpu] = malloc(sizeof(*lp_cpu[cpu]), M_DEVBUF, 262 M_WAITOK | M_ZERO); 263 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[0]); 264 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[1]); 265 } 266 } 267 SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); 268 269 static void 270 lock_prof_reset_wait(void) 271 { 272 273 /* 274 * Spin relinquishing our cpu so that quiesce_all_cpus may 275 * complete. 276 */ 277 while (lock_prof_resetting) 278 sched_relinquish(curthread); 279 } 280 281 static void 282 lock_prof_reset(void) 283 { 284 struct lock_prof_cpu *lpc; 285 int enabled, i, cpu; 286 287 /* 288 * We not only race with acquiring and releasing locks but also 289 * thread exit. To be certain that threads exit without valid head 290 * pointers they must see resetting set before enabled is cleared. 291 * Otherwise a lock may not be removed from a per-thread list due 292 * to disabled being set but not wait for reset() to remove it below. 293 */ 294 atomic_store_rel_int(&lock_prof_resetting, 1); 295 enabled = lock_prof_enable; 296 lock_prof_enable = 0; 297 quiesce_all_cpus("profreset", 0); 298 /* 299 * Some objects may have migrated between CPUs. Clear all links 300 * before we zero the structures. Some items may still be linked 301 * into per-thread lists as well. 302 */ 303 for (cpu = 0; cpu <= mp_maxid; cpu++) { 304 lpc = lp_cpu[cpu]; 305 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 306 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 307 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 308 } 309 } 310 for (cpu = 0; cpu <= mp_maxid; cpu++) { 311 lpc = lp_cpu[cpu]; 312 bzero(lpc, sizeof(*lpc)); 313 lock_prof_init_type(&lpc->lpc_types[0]); 314 lock_prof_init_type(&lpc->lpc_types[1]); 315 } 316 atomic_store_rel_int(&lock_prof_resetting, 0); 317 lock_prof_enable = enabled; 318 } 319 320 static void 321 lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 322 { 323 const char *p; 324 325 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 326 sbuf_printf(sb, 327 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", 328 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, 329 lp->cnt_wait / 1000, lp->cnt_cur, 330 lp->cnt_cur == 0 ? (uintmax_t)0 : 331 lp->cnt_tot / (lp->cnt_cur * 1000), 332 lp->cnt_cur == 0 ? (uintmax_t)0 : 333 lp->cnt_wait / (lp->cnt_cur * 1000), 334 (uintmax_t)0, lp->cnt_contest_locking, 335 p, lp->line, lp->class->lc_name, lp->name); 336 } 337 338 static void 339 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 340 int spin, int t) 341 { 342 struct lock_prof_type *type; 343 struct lock_prof *l; 344 int cpu; 345 346 dst->file = match->file; 347 dst->line = match->line; 348 dst->class = match->class; 349 dst->name = match->name; 350 351 for (cpu = 0; cpu <= mp_maxid; cpu++) { 352 if (lp_cpu[cpu] == NULL) 353 continue; 354 type = &lp_cpu[cpu]->lpc_types[spin]; 355 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 356 if (l->ticks == t) 357 continue; 358 if (l->file != match->file || l->line != match->line || 359 l->name != match->name) 360 continue; 361 l->ticks = t; 362 if (l->cnt_max > dst->cnt_max) 363 dst->cnt_max = l->cnt_max; 364 if (l->cnt_wait_max > dst->cnt_wait_max) 365 dst->cnt_wait_max = l->cnt_wait_max; 366 dst->cnt_tot += l->cnt_tot; 367 dst->cnt_wait += l->cnt_wait; 368 dst->cnt_cur += l->cnt_cur; 369 dst->cnt_contest_locking += l->cnt_contest_locking; 370 } 371 } 372 373 } 374 375 static void 376 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 377 int t) 378 { 379 struct lock_prof *l; 380 int i; 381 382 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 383 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 384 struct lock_prof lp = {}; 385 386 if (l->ticks == t) 387 continue; 388 lock_prof_sum(l, &lp, i, spin, t); 389 lock_prof_output(&lp, sb); 390 } 391 } 392 } 393 394 static int 395 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 396 { 397 struct sbuf *sb; 398 int error, cpu, t; 399 int enabled; 400 401 error = sysctl_wire_old_buffer(req, 0); 402 if (error != 0) 403 return (error); 404 sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req); 405 sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n", 406 "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); 407 enabled = lock_prof_enable; 408 lock_prof_enable = 0; 409 quiesce_all_cpus("profstat", 0); 410 t = ticks; 411 for (cpu = 0; cpu <= mp_maxid; cpu++) { 412 if (lp_cpu[cpu] == NULL) 413 continue; 414 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[0], sb, 0, t); 415 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[1], sb, 1, t); 416 } 417 lock_prof_enable = enabled; 418 419 error = sbuf_finish(sb); 420 /* Output a trailing NUL. */ 421 if (error == 0) 422 error = SYSCTL_OUT(req, "", 1); 423 sbuf_delete(sb); 424 return (error); 425 } 426 427 static int 428 enable_lock_prof(SYSCTL_HANDLER_ARGS) 429 { 430 int error, v; 431 432 v = lock_prof_enable; 433 error = sysctl_handle_int(oidp, &v, v, req); 434 if (error) 435 return (error); 436 if (req->newptr == NULL) 437 return (error); 438 if (v == lock_prof_enable) 439 return (0); 440 if (v == 1) 441 lock_prof_reset(); 442 lock_prof_enable = !!v; 443 444 return (0); 445 } 446 447 static int 448 reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) 449 { 450 int error, v; 451 452 v = 0; 453 error = sysctl_handle_int(oidp, &v, 0, req); 454 if (error) 455 return (error); 456 if (req->newptr == NULL) 457 return (error); 458 if (v == 0) 459 return (0); 460 lock_prof_reset(); 461 462 return (0); 463 } 464 465 static struct lock_prof * 466 lock_profile_lookup(struct lock_object *lo, int spin, const char *file, 467 int line) 468 { 469 const char *unknown = "(unknown)"; 470 struct lock_prof_type *type; 471 struct lock_prof *lp; 472 struct lphead *head; 473 const char *p; 474 u_int hash; 475 476 p = file; 477 if (p == NULL || *p == '\0') 478 p = unknown; 479 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; 480 hash &= LPROF_HASH_MASK; 481 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 482 head = &type->lpt_hash[hash]; 483 SLIST_FOREACH(lp, head, link) { 484 if (lp->line == line && lp->file == p && 485 lp->name == lo->lo_name) 486 return (lp); 487 488 } 489 lp = SLIST_FIRST(&type->lpt_lpalloc); 490 if (lp == NULL) { 491 lock_prof_rejected++; 492 return (lp); 493 } 494 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); 495 lp->file = p; 496 lp->line = line; 497 lp->class = LOCK_CLASS(lo); 498 lp->name = lo->lo_name; 499 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); 500 return (lp); 501 } 502 503 static struct lock_profile_object * 504 lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, 505 int line) 506 { 507 struct lock_profile_object *l; 508 struct lock_prof_type *type; 509 struct lpohead *head; 510 511 head = &curthread->td_lprof[spin]; 512 LIST_FOREACH(l, head, lpo_link) 513 if (l->lpo_obj == lo && l->lpo_file == file && 514 l->lpo_line == line) 515 return (l); 516 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 517 l = LIST_FIRST(&type->lpt_lpoalloc); 518 if (l == NULL) { 519 lock_prof_rejected++; 520 return (NULL); 521 } 522 LIST_REMOVE(l, lpo_link); 523 l->lpo_obj = lo; 524 l->lpo_file = file; 525 l->lpo_line = line; 526 l->lpo_cnt = 0; 527 LIST_INSERT_HEAD(head, l, lpo_link); 528 529 return (l); 530 } 531 532 void 533 lock_profile_obtain_lock_success(struct lock_object *lo, int contested, 534 uint64_t waittime, const char *file, int line) 535 { 536 static int lock_prof_count; 537 struct lock_profile_object *l; 538 int spin; 539 540 if (SCHEDULER_STOPPED()) 541 return; 542 543 /* don't reset the timer when/if recursing */ 544 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 545 return; 546 if (lock_prof_skipcount && 547 (++lock_prof_count % lock_prof_skipcount) != 0) 548 return; 549 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 550 if (spin && lock_prof_skipspin == 1) 551 return; 552 critical_enter(); 553 /* Recheck enabled now that we're in a critical section. */ 554 if (lock_prof_enable == 0) 555 goto out; 556 l = lock_profile_object_lookup(lo, spin, file, line); 557 if (l == NULL) 558 goto out; 559 l->lpo_cnt++; 560 if (++l->lpo_ref > 1) 561 goto out; 562 l->lpo_contest_locking = contested; 563 l->lpo_acqtime = nanoseconds(); 564 if (waittime && (l->lpo_acqtime > waittime)) 565 l->lpo_waittime = l->lpo_acqtime - waittime; 566 else 567 l->lpo_waittime = 0; 568 out: 569 critical_exit(); 570 } 571 572 void 573 lock_profile_thread_exit(struct thread *td) 574 { 575 #ifdef INVARIANTS 576 struct lock_profile_object *l; 577 578 MPASS(curthread->td_critnest == 0); 579 #endif 580 /* 581 * If lock profiling was disabled we have to wait for reset to 582 * clear our pointers before we can exit safely. 583 */ 584 lock_prof_reset_wait(); 585 #ifdef INVARIANTS 586 LIST_FOREACH(l, &td->td_lprof[0], lpo_link) 587 printf("thread still holds lock acquired at %s:%d\n", 588 l->lpo_file, l->lpo_line); 589 LIST_FOREACH(l, &td->td_lprof[1], lpo_link) 590 printf("thread still holds lock acquired at %s:%d\n", 591 l->lpo_file, l->lpo_line); 592 #endif 593 MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL); 594 MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL); 595 } 596 597 void 598 lock_profile_release_lock(struct lock_object *lo) 599 { 600 struct lock_profile_object *l; 601 struct lock_prof_type *type; 602 struct lock_prof *lp; 603 uint64_t curtime, holdtime; 604 struct lpohead *head; 605 int spin; 606 607 if (SCHEDULER_STOPPED()) 608 return; 609 if (lo->lo_flags & LO_NOPROFILE) 610 return; 611 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 612 head = &curthread->td_lprof[spin]; 613 if (LIST_FIRST(head) == NULL) 614 return; 615 critical_enter(); 616 /* Recheck enabled now that we're in a critical section. */ 617 if (lock_prof_enable == 0 && lock_prof_resetting == 1) 618 goto out; 619 /* 620 * If lock profiling is not enabled we still want to remove the 621 * lpo from our queue. 622 */ 623 LIST_FOREACH(l, head, lpo_link) 624 if (l->lpo_obj == lo) 625 break; 626 if (l == NULL) 627 goto out; 628 if (--l->lpo_ref > 0) 629 goto out; 630 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 631 if (lp == NULL) 632 goto release; 633 curtime = nanoseconds(); 634 if (curtime < l->lpo_acqtime) 635 goto release; 636 holdtime = curtime - l->lpo_acqtime; 637 638 /* 639 * Record if the lock has been held longer now than ever 640 * before. 641 */ 642 if (holdtime > lp->cnt_max) 643 lp->cnt_max = holdtime; 644 if (l->lpo_waittime > lp->cnt_wait_max) 645 lp->cnt_wait_max = l->lpo_waittime; 646 lp->cnt_tot += holdtime; 647 lp->cnt_wait += l->lpo_waittime; 648 lp->cnt_contest_locking += l->lpo_contest_locking; 649 lp->cnt_cur += l->lpo_cnt; 650 release: 651 LIST_REMOVE(l, lpo_link); 652 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 653 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 654 out: 655 critical_exit(); 656 } 657 658 static SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging"); 659 static SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, 660 "lock profiling"); 661 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 662 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 663 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW, 664 &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions."); 665 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 666 &lock_prof_rejected, 0, "Number of rejected profiling records"); 667 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, 668 NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics"); 669 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, 670 NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics"); 671 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, 672 NULL, 0, enable_lock_prof, "I", "Enable lock profiling"); 673 674 #endif
Cache object: d49abeb58a5b9c62c598f3c95f0f18b1
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