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