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/8.3/sys/kern/subr_lock.c 221125 2011-04-27 18:00:46Z 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_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 u_int64_t lpo_acqtime; 142 u_int64_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 /* SWAG: sbuf size = avg stat. line size * number of locks */ 194 #define LPROF_SBUF_SIZE 256 * 400 195 196 static int lock_prof_rejected; 197 static int lock_prof_skipspin; 198 static int lock_prof_skipcount; 199 200 #ifndef USE_CPU_NANOSECONDS 201 u_int64_t 202 nanoseconds(void) 203 { 204 struct bintime bt; 205 u_int64_t ns; 206 207 binuptime(&bt); 208 /* From bintime2timespec */ 209 ns = bt.sec * (u_int64_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 /* 245 * To be certain that lock profiling has idled on all cpus before we 246 * reset, we schedule the resetting thread on all active cpus. Since 247 * all operations happen within critical sections we can be sure that 248 * it is safe to zero the profiling structures. 249 */ 250 static void 251 lock_prof_idle(void) 252 { 253 struct thread *td; 254 int cpu; 255 256 td = curthread; 257 thread_lock(td); 258 CPU_FOREACH(cpu) { 259 sched_bind(td, cpu); 260 } 261 sched_unbind(td); 262 thread_unlock(td); 263 } 264 265 static void 266 lock_prof_reset_wait(void) 267 { 268 269 /* 270 * Spin relinquishing our cpu so that lock_prof_idle may 271 * run on it. 272 */ 273 while (lock_prof_resetting) 274 sched_relinquish(curthread); 275 } 276 277 static void 278 lock_prof_reset(void) 279 { 280 struct lock_prof_cpu *lpc; 281 int enabled, i, cpu; 282 283 /* 284 * We not only race with acquiring and releasing locks but also 285 * thread exit. To be certain that threads exit without valid head 286 * pointers they must see resetting set before enabled is cleared. 287 * Otherwise a lock may not be removed from a per-thread list due 288 * to disabled being set but not wait for reset() to remove it below. 289 */ 290 atomic_store_rel_int(&lock_prof_resetting, 1); 291 enabled = lock_prof_enable; 292 lock_prof_enable = 0; 293 lock_prof_idle(); 294 /* 295 * Some objects may have migrated between CPUs. Clear all links 296 * before we zero the structures. Some items may still be linked 297 * into per-thread lists as well. 298 */ 299 for (cpu = 0; cpu <= mp_maxid; cpu++) { 300 lpc = lp_cpu[cpu]; 301 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 302 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 303 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 304 } 305 } 306 for (cpu = 0; cpu <= mp_maxid; cpu++) { 307 lpc = lp_cpu[cpu]; 308 bzero(lpc, sizeof(*lpc)); 309 lock_prof_init_type(&lpc->lpc_types[0]); 310 lock_prof_init_type(&lpc->lpc_types[1]); 311 } 312 atomic_store_rel_int(&lock_prof_resetting, 0); 313 lock_prof_enable = enabled; 314 } 315 316 static void 317 lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 318 { 319 const char *p; 320 321 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 322 sbuf_printf(sb, 323 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", 324 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, 325 lp->cnt_wait / 1000, lp->cnt_cur, 326 lp->cnt_cur == 0 ? (uintmax_t)0 : 327 lp->cnt_tot / (lp->cnt_cur * 1000), 328 lp->cnt_cur == 0 ? (uintmax_t)0 : 329 lp->cnt_wait / (lp->cnt_cur * 1000), 330 (uintmax_t)0, lp->cnt_contest_locking, 331 p, lp->line, lp->class->lc_name, lp->name); 332 } 333 334 static void 335 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 336 int spin, int t) 337 { 338 struct lock_prof_type *type; 339 struct lock_prof *l; 340 int cpu; 341 342 dst->file = match->file; 343 dst->line = match->line; 344 dst->class = match->class; 345 dst->name = match->name; 346 347 for (cpu = 0; cpu <= mp_maxid; cpu++) { 348 if (lp_cpu[cpu] == NULL) 349 continue; 350 type = &lp_cpu[cpu]->lpc_types[spin]; 351 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 352 if (l->ticks == t) 353 continue; 354 if (l->file != match->file || l->line != match->line || 355 l->name != match->name) 356 continue; 357 l->ticks = t; 358 if (l->cnt_max > dst->cnt_max) 359 dst->cnt_max = l->cnt_max; 360 if (l->cnt_wait_max > dst->cnt_wait_max) 361 dst->cnt_wait_max = l->cnt_wait_max; 362 dst->cnt_tot += l->cnt_tot; 363 dst->cnt_wait += l->cnt_wait; 364 dst->cnt_cur += l->cnt_cur; 365 dst->cnt_contest_locking += l->cnt_contest_locking; 366 } 367 } 368 369 } 370 371 static void 372 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 373 int t) 374 { 375 struct lock_prof *l; 376 int i; 377 378 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 379 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 380 struct lock_prof lp = {}; 381 382 if (l->ticks == t) 383 continue; 384 lock_prof_sum(l, &lp, i, spin, t); 385 lock_prof_output(&lp, sb); 386 if (sbuf_overflowed(sb)) 387 return; 388 } 389 } 390 } 391 392 static int 393 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 394 { 395 static int multiplier = 1; 396 struct sbuf *sb; 397 int error, cpu, t; 398 int enabled; 399 400 retry_sbufops: 401 sb = sbuf_new(NULL, NULL, LPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN); 402 sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n", 403 "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); 404 enabled = lock_prof_enable; 405 lock_prof_enable = 0; 406 lock_prof_idle(); 407 t = ticks; 408 for (cpu = 0; cpu <= mp_maxid; cpu++) { 409 if (lp_cpu[cpu] == NULL) 410 continue; 411 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[0], sb, 0, t); 412 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[1], sb, 1, t); 413 if (sbuf_overflowed(sb)) { 414 sbuf_delete(sb); 415 multiplier++; 416 goto retry_sbufops; 417 } 418 } 419 lock_prof_enable = enabled; 420 421 sbuf_finish(sb); 422 error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 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 /* don't reset the timer when/if recursing */ 541 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 542 return; 543 if (lock_prof_skipcount && 544 (++lock_prof_count % lock_prof_skipcount) != 0) 545 return; 546 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 547 if (spin && lock_prof_skipspin == 1) 548 return; 549 critical_enter(); 550 /* Recheck enabled now that we're in a critical section. */ 551 if (lock_prof_enable == 0) 552 goto out; 553 l = lock_profile_object_lookup(lo, spin, file, line); 554 if (l == NULL) 555 goto out; 556 l->lpo_cnt++; 557 if (++l->lpo_ref > 1) 558 goto out; 559 l->lpo_contest_locking = contested; 560 l->lpo_acqtime = nanoseconds(); 561 if (waittime && (l->lpo_acqtime > waittime)) 562 l->lpo_waittime = l->lpo_acqtime - waittime; 563 else 564 l->lpo_waittime = 0; 565 out: 566 critical_exit(); 567 } 568 569 void 570 lock_profile_thread_exit(struct thread *td) 571 { 572 #ifdef INVARIANTS 573 struct lock_profile_object *l; 574 575 MPASS(curthread->td_critnest == 0); 576 #endif 577 /* 578 * If lock profiling was disabled we have to wait for reset to 579 * clear our pointers before we can exit safely. 580 */ 581 lock_prof_reset_wait(); 582 #ifdef INVARIANTS 583 LIST_FOREACH(l, &td->td_lprof[0], lpo_link) 584 printf("thread still holds lock acquired at %s:%d\n", 585 l->lpo_file, l->lpo_line); 586 LIST_FOREACH(l, &td->td_lprof[1], lpo_link) 587 printf("thread still holds lock acquired at %s:%d\n", 588 l->lpo_file, l->lpo_line); 589 #endif 590 MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL); 591 MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL); 592 } 593 594 void 595 lock_profile_release_lock(struct lock_object *lo) 596 { 597 struct lock_profile_object *l; 598 struct lock_prof_type *type; 599 struct lock_prof *lp; 600 u_int64_t curtime, holdtime; 601 struct lpohead *head; 602 int spin; 603 604 if (lo->lo_flags & LO_NOPROFILE) 605 return; 606 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 607 head = &curthread->td_lprof[spin]; 608 if (LIST_FIRST(head) == NULL) 609 return; 610 critical_enter(); 611 /* Recheck enabled now that we're in a critical section. */ 612 if (lock_prof_enable == 0 && lock_prof_resetting == 1) 613 goto out; 614 /* 615 * If lock profiling is not enabled we still want to remove the 616 * lpo from our queue. 617 */ 618 LIST_FOREACH(l, head, lpo_link) 619 if (l->lpo_obj == lo) 620 break; 621 if (l == NULL) 622 goto out; 623 if (--l->lpo_ref > 0) 624 goto out; 625 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 626 if (lp == NULL) 627 goto release; 628 curtime = nanoseconds(); 629 if (curtime < l->lpo_acqtime) 630 goto release; 631 holdtime = curtime - l->lpo_acqtime; 632 633 /* 634 * Record if the lock has been held longer now than ever 635 * before. 636 */ 637 if (holdtime > lp->cnt_max) 638 lp->cnt_max = holdtime; 639 if (l->lpo_waittime > lp->cnt_wait_max) 640 lp->cnt_wait_max = l->lpo_waittime; 641 lp->cnt_tot += holdtime; 642 lp->cnt_wait += l->lpo_waittime; 643 lp->cnt_contest_locking += l->lpo_contest_locking; 644 lp->cnt_cur += l->lpo_cnt; 645 release: 646 LIST_REMOVE(l, lpo_link); 647 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 648 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 649 out: 650 critical_exit(); 651 } 652 653 SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging"); 654 SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, "lock profiling"); 655 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 656 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 657 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW, 658 &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions."); 659 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 660 &lock_prof_rejected, 0, "Number of rejected profiling records"); 661 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, 662 NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics"); 663 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, 664 NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics"); 665 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, 666 NULL, 0, enable_lock_prof, "I", "Enable lock profiling"); 667 668 #endif
Cache object: bc93166051a0058f83c8df0f72019f2d
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