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 * 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: releng/10.0/sys/kern/subr_lock.c 252209 2013-06-25 18:44:15Z jhb $"); 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/lock.h> 46 #include <sys/lock_profile.h> 47 #include <sys/malloc.h> 48 #include <sys/mutex.h> 49 #include <sys/pcpu.h> 50 #include <sys/proc.h> 51 #include <sys/sbuf.h> 52 #include <sys/sched.h> 53 #include <sys/smp.h> 54 #include <sys/sysctl.h> 55 56 #ifdef DDB 57 #include <ddb/ddb.h> 58 #endif 59 60 #include <machine/cpufunc.h> 61 62 CTASSERT(LOCK_CLASS_MAX == 15); 63 64 struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = { 65 &lock_class_mtx_spin, 66 &lock_class_mtx_sleep, 67 &lock_class_sx, 68 &lock_class_rm, 69 &lock_class_rm_sleepable, 70 &lock_class_rw, 71 &lock_class_lockmgr, 72 }; 73 74 void 75 lock_init(struct lock_object *lock, struct lock_class *class, const char *name, 76 const char *type, int flags) 77 { 78 int i; 79 80 /* Check for double-init and zero object. */ 81 KASSERT(!lock_initalized(lock), ("lock \"%s\" %p already initialized", 82 name, lock)); 83 84 /* Look up lock class to find its index. */ 85 for (i = 0; i < LOCK_CLASS_MAX; i++) 86 if (lock_classes[i] == class) { 87 lock->lo_flags = i << LO_CLASSSHIFT; 88 break; 89 } 90 KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class)); 91 92 /* Initialize the lock object. */ 93 lock->lo_name = name; 94 lock->lo_flags |= flags | LO_INITIALIZED; 95 LOCK_LOG_INIT(lock, 0); 96 WITNESS_INIT(lock, (type != NULL) ? type : name); 97 } 98 99 void 100 lock_destroy(struct lock_object *lock) 101 { 102 103 KASSERT(lock_initalized(lock), ("lock %p is not initialized", lock)); 104 WITNESS_DESTROY(lock); 105 LOCK_LOG_DESTROY(lock, 0); 106 lock->lo_flags &= ~LO_INITIALIZED; 107 } 108 109 #ifdef DDB 110 DB_SHOW_COMMAND(lock, db_show_lock) 111 { 112 struct lock_object *lock; 113 struct lock_class *class; 114 115 if (!have_addr) 116 return; 117 lock = (struct lock_object *)addr; 118 if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) { 119 db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock)); 120 return; 121 } 122 class = LOCK_CLASS(lock); 123 db_printf(" class: %s\n", class->lc_name); 124 db_printf(" name: %s\n", lock->lo_name); 125 class->lc_ddb_show(lock); 126 } 127 #endif 128 129 #ifdef LOCK_PROFILING 130 131 /* 132 * One object per-thread for each lock the thread owns. Tracks individual 133 * lock instances. 134 */ 135 struct lock_profile_object { 136 LIST_ENTRY(lock_profile_object) lpo_link; 137 struct lock_object *lpo_obj; 138 const char *lpo_file; 139 int lpo_line; 140 uint16_t lpo_ref; 141 uint16_t lpo_cnt; 142 uint64_t lpo_acqtime; 143 uint64_t lpo_waittime; 144 u_int lpo_contest_locking; 145 }; 146 147 /* 148 * One lock_prof for each (file, line, lock object) triple. 149 */ 150 struct lock_prof { 151 SLIST_ENTRY(lock_prof) link; 152 struct lock_class *class; 153 const char *file; 154 const char *name; 155 int line; 156 int ticks; 157 uintmax_t cnt_wait_max; 158 uintmax_t cnt_max; 159 uintmax_t cnt_tot; 160 uintmax_t cnt_wait; 161 uintmax_t cnt_cur; 162 uintmax_t cnt_contest_locking; 163 }; 164 165 SLIST_HEAD(lphead, lock_prof); 166 167 #define LPROF_HASH_SIZE 4096 168 #define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1) 169 #define LPROF_CACHE_SIZE 4096 170 171 /* 172 * Array of objects and profs for each type of object for each cpu. Spinlocks 173 * are handled separately because a thread may be preempted and acquire a 174 * spinlock while in the lock profiling code of a non-spinlock. In this way 175 * we only need a critical section to protect the per-cpu lists. 176 */ 177 struct lock_prof_type { 178 struct lphead lpt_lpalloc; 179 struct lpohead lpt_lpoalloc; 180 struct lphead lpt_hash[LPROF_HASH_SIZE]; 181 struct lock_prof lpt_prof[LPROF_CACHE_SIZE]; 182 struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE]; 183 }; 184 185 struct lock_prof_cpu { 186 struct lock_prof_type lpc_types[2]; /* One for spin one for other. */ 187 }; 188 189 struct lock_prof_cpu *lp_cpu[MAXCPU]; 190 191 volatile int lock_prof_enable = 0; 192 static volatile int lock_prof_resetting; 193 194 #define LPROF_SBUF_SIZE 256 195 196 static int lock_prof_rejected; 197 static int lock_prof_skipspin; 198 static int lock_prof_skipcount; 199 200 #ifndef USE_CPU_NANOSECONDS 201 uint64_t 202 nanoseconds(void) 203 { 204 struct bintime bt; 205 uint64_t ns; 206 207 binuptime(&bt); 208 /* From bintime2timespec */ 209 ns = bt.sec * (uint64_t)1000000000; 210 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; 211 return (ns); 212 } 213 #endif 214 215 static void 216 lock_prof_init_type(struct lock_prof_type *type) 217 { 218 int i; 219 220 SLIST_INIT(&type->lpt_lpalloc); 221 LIST_INIT(&type->lpt_lpoalloc); 222 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 223 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], 224 link); 225 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], 226 lpo_link); 227 } 228 } 229 230 static void 231 lock_prof_init(void *arg) 232 { 233 int cpu; 234 235 for (cpu = 0; cpu <= mp_maxid; cpu++) { 236 lp_cpu[cpu] = malloc(sizeof(*lp_cpu[cpu]), M_DEVBUF, 237 M_WAITOK | M_ZERO); 238 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[0]); 239 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[1]); 240 } 241 } 242 SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); 243 244 static void 245 lock_prof_reset_wait(void) 246 { 247 248 /* 249 * Spin relinquishing our cpu so that quiesce_all_cpus may 250 * complete. 251 */ 252 while (lock_prof_resetting) 253 sched_relinquish(curthread); 254 } 255 256 static void 257 lock_prof_reset(void) 258 { 259 struct lock_prof_cpu *lpc; 260 int enabled, i, cpu; 261 262 /* 263 * We not only race with acquiring and releasing locks but also 264 * thread exit. To be certain that threads exit without valid head 265 * pointers they must see resetting set before enabled is cleared. 266 * Otherwise a lock may not be removed from a per-thread list due 267 * to disabled being set but not wait for reset() to remove it below. 268 */ 269 atomic_store_rel_int(&lock_prof_resetting, 1); 270 enabled = lock_prof_enable; 271 lock_prof_enable = 0; 272 quiesce_all_cpus("profreset", 0); 273 /* 274 * Some objects may have migrated between CPUs. Clear all links 275 * before we zero the structures. Some items may still be linked 276 * into per-thread lists as well. 277 */ 278 for (cpu = 0; cpu <= mp_maxid; cpu++) { 279 lpc = lp_cpu[cpu]; 280 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 281 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 282 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 283 } 284 } 285 for (cpu = 0; cpu <= mp_maxid; cpu++) { 286 lpc = lp_cpu[cpu]; 287 bzero(lpc, sizeof(*lpc)); 288 lock_prof_init_type(&lpc->lpc_types[0]); 289 lock_prof_init_type(&lpc->lpc_types[1]); 290 } 291 atomic_store_rel_int(&lock_prof_resetting, 0); 292 lock_prof_enable = enabled; 293 } 294 295 static void 296 lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 297 { 298 const char *p; 299 300 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 301 sbuf_printf(sb, 302 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", 303 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, 304 lp->cnt_wait / 1000, lp->cnt_cur, 305 lp->cnt_cur == 0 ? (uintmax_t)0 : 306 lp->cnt_tot / (lp->cnt_cur * 1000), 307 lp->cnt_cur == 0 ? (uintmax_t)0 : 308 lp->cnt_wait / (lp->cnt_cur * 1000), 309 (uintmax_t)0, lp->cnt_contest_locking, 310 p, lp->line, lp->class->lc_name, lp->name); 311 } 312 313 static void 314 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 315 int spin, int t) 316 { 317 struct lock_prof_type *type; 318 struct lock_prof *l; 319 int cpu; 320 321 dst->file = match->file; 322 dst->line = match->line; 323 dst->class = match->class; 324 dst->name = match->name; 325 326 for (cpu = 0; cpu <= mp_maxid; cpu++) { 327 if (lp_cpu[cpu] == NULL) 328 continue; 329 type = &lp_cpu[cpu]->lpc_types[spin]; 330 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 331 if (l->ticks == t) 332 continue; 333 if (l->file != match->file || l->line != match->line || 334 l->name != match->name) 335 continue; 336 l->ticks = t; 337 if (l->cnt_max > dst->cnt_max) 338 dst->cnt_max = l->cnt_max; 339 if (l->cnt_wait_max > dst->cnt_wait_max) 340 dst->cnt_wait_max = l->cnt_wait_max; 341 dst->cnt_tot += l->cnt_tot; 342 dst->cnt_wait += l->cnt_wait; 343 dst->cnt_cur += l->cnt_cur; 344 dst->cnt_contest_locking += l->cnt_contest_locking; 345 } 346 } 347 348 } 349 350 static void 351 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 352 int t) 353 { 354 struct lock_prof *l; 355 int i; 356 357 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 358 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 359 struct lock_prof lp = {}; 360 361 if (l->ticks == t) 362 continue; 363 lock_prof_sum(l, &lp, i, spin, t); 364 lock_prof_output(&lp, sb); 365 } 366 } 367 } 368 369 static int 370 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 371 { 372 struct sbuf *sb; 373 int error, cpu, t; 374 int enabled; 375 376 error = sysctl_wire_old_buffer(req, 0); 377 if (error != 0) 378 return (error); 379 sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req); 380 sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n", 381 "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); 382 enabled = lock_prof_enable; 383 lock_prof_enable = 0; 384 quiesce_all_cpus("profstat", 0); 385 t = ticks; 386 for (cpu = 0; cpu <= mp_maxid; cpu++) { 387 if (lp_cpu[cpu] == NULL) 388 continue; 389 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[0], sb, 0, t); 390 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[1], sb, 1, t); 391 } 392 lock_prof_enable = enabled; 393 394 error = sbuf_finish(sb); 395 /* Output a trailing NUL. */ 396 if (error == 0) 397 error = SYSCTL_OUT(req, "", 1); 398 sbuf_delete(sb); 399 return (error); 400 } 401 402 static int 403 enable_lock_prof(SYSCTL_HANDLER_ARGS) 404 { 405 int error, v; 406 407 v = lock_prof_enable; 408 error = sysctl_handle_int(oidp, &v, v, req); 409 if (error) 410 return (error); 411 if (req->newptr == NULL) 412 return (error); 413 if (v == lock_prof_enable) 414 return (0); 415 if (v == 1) 416 lock_prof_reset(); 417 lock_prof_enable = !!v; 418 419 return (0); 420 } 421 422 static int 423 reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) 424 { 425 int error, v; 426 427 v = 0; 428 error = sysctl_handle_int(oidp, &v, 0, req); 429 if (error) 430 return (error); 431 if (req->newptr == NULL) 432 return (error); 433 if (v == 0) 434 return (0); 435 lock_prof_reset(); 436 437 return (0); 438 } 439 440 static struct lock_prof * 441 lock_profile_lookup(struct lock_object *lo, int spin, const char *file, 442 int line) 443 { 444 const char *unknown = "(unknown)"; 445 struct lock_prof_type *type; 446 struct lock_prof *lp; 447 struct lphead *head; 448 const char *p; 449 u_int hash; 450 451 p = file; 452 if (p == NULL || *p == '\0') 453 p = unknown; 454 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; 455 hash &= LPROF_HASH_MASK; 456 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 457 head = &type->lpt_hash[hash]; 458 SLIST_FOREACH(lp, head, link) { 459 if (lp->line == line && lp->file == p && 460 lp->name == lo->lo_name) 461 return (lp); 462 463 } 464 lp = SLIST_FIRST(&type->lpt_lpalloc); 465 if (lp == NULL) { 466 lock_prof_rejected++; 467 return (lp); 468 } 469 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); 470 lp->file = p; 471 lp->line = line; 472 lp->class = LOCK_CLASS(lo); 473 lp->name = lo->lo_name; 474 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); 475 return (lp); 476 } 477 478 static struct lock_profile_object * 479 lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, 480 int line) 481 { 482 struct lock_profile_object *l; 483 struct lock_prof_type *type; 484 struct lpohead *head; 485 486 head = &curthread->td_lprof[spin]; 487 LIST_FOREACH(l, head, lpo_link) 488 if (l->lpo_obj == lo && l->lpo_file == file && 489 l->lpo_line == line) 490 return (l); 491 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 492 l = LIST_FIRST(&type->lpt_lpoalloc); 493 if (l == NULL) { 494 lock_prof_rejected++; 495 return (NULL); 496 } 497 LIST_REMOVE(l, lpo_link); 498 l->lpo_obj = lo; 499 l->lpo_file = file; 500 l->lpo_line = line; 501 l->lpo_cnt = 0; 502 LIST_INSERT_HEAD(head, l, lpo_link); 503 504 return (l); 505 } 506 507 void 508 lock_profile_obtain_lock_success(struct lock_object *lo, int contested, 509 uint64_t waittime, const char *file, int line) 510 { 511 static int lock_prof_count; 512 struct lock_profile_object *l; 513 int spin; 514 515 if (SCHEDULER_STOPPED()) 516 return; 517 518 /* don't reset the timer when/if recursing */ 519 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 520 return; 521 if (lock_prof_skipcount && 522 (++lock_prof_count % lock_prof_skipcount) != 0) 523 return; 524 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 525 if (spin && lock_prof_skipspin == 1) 526 return; 527 critical_enter(); 528 /* Recheck enabled now that we're in a critical section. */ 529 if (lock_prof_enable == 0) 530 goto out; 531 l = lock_profile_object_lookup(lo, spin, file, line); 532 if (l == NULL) 533 goto out; 534 l->lpo_cnt++; 535 if (++l->lpo_ref > 1) 536 goto out; 537 l->lpo_contest_locking = contested; 538 l->lpo_acqtime = nanoseconds(); 539 if (waittime && (l->lpo_acqtime > waittime)) 540 l->lpo_waittime = l->lpo_acqtime - waittime; 541 else 542 l->lpo_waittime = 0; 543 out: 544 critical_exit(); 545 } 546 547 void 548 lock_profile_thread_exit(struct thread *td) 549 { 550 #ifdef INVARIANTS 551 struct lock_profile_object *l; 552 553 MPASS(curthread->td_critnest == 0); 554 #endif 555 /* 556 * If lock profiling was disabled we have to wait for reset to 557 * clear our pointers before we can exit safely. 558 */ 559 lock_prof_reset_wait(); 560 #ifdef INVARIANTS 561 LIST_FOREACH(l, &td->td_lprof[0], lpo_link) 562 printf("thread still holds lock acquired at %s:%d\n", 563 l->lpo_file, l->lpo_line); 564 LIST_FOREACH(l, &td->td_lprof[1], lpo_link) 565 printf("thread still holds lock acquired at %s:%d\n", 566 l->lpo_file, l->lpo_line); 567 #endif 568 MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL); 569 MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL); 570 } 571 572 void 573 lock_profile_release_lock(struct lock_object *lo) 574 { 575 struct lock_profile_object *l; 576 struct lock_prof_type *type; 577 struct lock_prof *lp; 578 uint64_t curtime, holdtime; 579 struct lpohead *head; 580 int spin; 581 582 if (SCHEDULER_STOPPED()) 583 return; 584 if (lo->lo_flags & LO_NOPROFILE) 585 return; 586 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 587 head = &curthread->td_lprof[spin]; 588 if (LIST_FIRST(head) == NULL) 589 return; 590 critical_enter(); 591 /* Recheck enabled now that we're in a critical section. */ 592 if (lock_prof_enable == 0 && lock_prof_resetting == 1) 593 goto out; 594 /* 595 * If lock profiling is not enabled we still want to remove the 596 * lpo from our queue. 597 */ 598 LIST_FOREACH(l, head, lpo_link) 599 if (l->lpo_obj == lo) 600 break; 601 if (l == NULL) 602 goto out; 603 if (--l->lpo_ref > 0) 604 goto out; 605 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 606 if (lp == NULL) 607 goto release; 608 curtime = nanoseconds(); 609 if (curtime < l->lpo_acqtime) 610 goto release; 611 holdtime = curtime - l->lpo_acqtime; 612 613 /* 614 * Record if the lock has been held longer now than ever 615 * before. 616 */ 617 if (holdtime > lp->cnt_max) 618 lp->cnt_max = holdtime; 619 if (l->lpo_waittime > lp->cnt_wait_max) 620 lp->cnt_wait_max = l->lpo_waittime; 621 lp->cnt_tot += holdtime; 622 lp->cnt_wait += l->lpo_waittime; 623 lp->cnt_contest_locking += l->lpo_contest_locking; 624 lp->cnt_cur += l->lpo_cnt; 625 release: 626 LIST_REMOVE(l, lpo_link); 627 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 628 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 629 out: 630 critical_exit(); 631 } 632 633 static SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging"); 634 static SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, 635 "lock profiling"); 636 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 637 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 638 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW, 639 &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions."); 640 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 641 &lock_prof_rejected, 0, "Number of rejected profiling records"); 642 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, 643 NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics"); 644 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, 645 NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics"); 646 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, 647 NULL, 0, enable_lock_prof, "I", "Enable lock profiling"); 648 649 #endif
Cache object: 2b3322dca0370a1fc854b92b91ef130c
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