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/8.2/sys/kern/subr_lock.c 215588 2010-11-20 20:34:13Z brucec $"); 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/mutex.h> 50 #include <sys/pcpu.h> 51 #include <sys/proc.h> 52 #include <sys/sbuf.h> 53 #include <sys/sched.h> 54 #include <sys/smp.h> 55 #include <sys/sysctl.h> 56 57 #ifdef DDB 58 #include <ddb/ddb.h> 59 #endif 60 61 #include <machine/cpufunc.h> 62 63 CTASSERT(LOCK_CLASS_MAX == 15); 64 65 struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = { 66 &lock_class_mtx_spin, 67 &lock_class_mtx_sleep, 68 &lock_class_sx, 69 &lock_class_rm, 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 u_int64_t lpo_acqtime; 143 u_int64_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 /* SWAG: sbuf size = avg stat. line size * number of locks */ 195 #define LPROF_SBUF_SIZE 256 * 400 196 197 static int lock_prof_rejected; 198 static int lock_prof_skipspin; 199 static int lock_prof_skipcount; 200 201 #ifndef USE_CPU_NANOSECONDS 202 u_int64_t 203 nanoseconds(void) 204 { 205 struct bintime bt; 206 u_int64_t ns; 207 208 binuptime(&bt); 209 /* From bintime2timespec */ 210 ns = bt.sec * (u_int64_t)1000000000; 211 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; 212 return (ns); 213 } 214 #endif 215 216 static void 217 lock_prof_init_type(struct lock_prof_type *type) 218 { 219 int i; 220 221 SLIST_INIT(&type->lpt_lpalloc); 222 LIST_INIT(&type->lpt_lpoalloc); 223 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 224 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], 225 link); 226 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], 227 lpo_link); 228 } 229 } 230 231 static void 232 lock_prof_init(void *arg) 233 { 234 int cpu; 235 236 for (cpu = 0; cpu <= mp_maxid; cpu++) { 237 lp_cpu[cpu] = malloc(sizeof(*lp_cpu[cpu]), M_DEVBUF, 238 M_WAITOK | M_ZERO); 239 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[0]); 240 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[1]); 241 } 242 } 243 SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); 244 245 /* 246 * To be certain that lock profiling has idled on all cpus before we 247 * reset, we schedule the resetting thread on all active cpus. Since 248 * all operations happen within critical sections we can be sure that 249 * it is safe to zero the profiling structures. 250 */ 251 static void 252 lock_prof_idle(void) 253 { 254 struct thread *td; 255 int cpu; 256 257 td = curthread; 258 thread_lock(td); 259 for (cpu = 0; cpu <= mp_maxid; cpu++) { 260 if (CPU_ABSENT(cpu)) 261 continue; 262 sched_bind(td, cpu); 263 } 264 sched_unbind(td); 265 thread_unlock(td); 266 } 267 268 static void 269 lock_prof_reset_wait(void) 270 { 271 272 /* 273 * Spin relinquishing our cpu so that lock_prof_idle may 274 * run on it. 275 */ 276 while (lock_prof_resetting) 277 sched_relinquish(curthread); 278 } 279 280 static void 281 lock_prof_reset(void) 282 { 283 struct lock_prof_cpu *lpc; 284 int enabled, i, cpu; 285 286 /* 287 * We not only race with acquiring and releasing locks but also 288 * thread exit. To be certain that threads exit without valid head 289 * pointers they must see resetting set before enabled is cleared. 290 * Otherwise a lock may not be removed from a per-thread list due 291 * to disabled being set but not wait for reset() to remove it below. 292 */ 293 atomic_store_rel_int(&lock_prof_resetting, 1); 294 enabled = lock_prof_enable; 295 lock_prof_enable = 0; 296 lock_prof_idle(); 297 /* 298 * Some objects may have migrated between CPUs. Clear all links 299 * before we zero the structures. Some items may still be linked 300 * into per-thread lists as well. 301 */ 302 for (cpu = 0; cpu <= mp_maxid; cpu++) { 303 lpc = lp_cpu[cpu]; 304 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 305 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 306 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 307 } 308 } 309 for (cpu = 0; cpu <= mp_maxid; cpu++) { 310 lpc = lp_cpu[cpu]; 311 bzero(lpc, sizeof(*lpc)); 312 lock_prof_init_type(&lpc->lpc_types[0]); 313 lock_prof_init_type(&lpc->lpc_types[1]); 314 } 315 atomic_store_rel_int(&lock_prof_resetting, 0); 316 lock_prof_enable = enabled; 317 } 318 319 static void 320 lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 321 { 322 const char *p; 323 324 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 325 sbuf_printf(sb, 326 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", 327 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, 328 lp->cnt_wait / 1000, lp->cnt_cur, 329 lp->cnt_cur == 0 ? (uintmax_t)0 : 330 lp->cnt_tot / (lp->cnt_cur * 1000), 331 lp->cnt_cur == 0 ? (uintmax_t)0 : 332 lp->cnt_wait / (lp->cnt_cur * 1000), 333 (uintmax_t)0, lp->cnt_contest_locking, 334 p, lp->line, lp->class->lc_name, lp->name); 335 } 336 337 static void 338 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 339 int spin, int t) 340 { 341 struct lock_prof_type *type; 342 struct lock_prof *l; 343 int cpu; 344 345 dst->file = match->file; 346 dst->line = match->line; 347 dst->class = match->class; 348 dst->name = match->name; 349 350 for (cpu = 0; cpu <= mp_maxid; cpu++) { 351 if (lp_cpu[cpu] == NULL) 352 continue; 353 type = &lp_cpu[cpu]->lpc_types[spin]; 354 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 355 if (l->ticks == t) 356 continue; 357 if (l->file != match->file || l->line != match->line || 358 l->name != match->name) 359 continue; 360 l->ticks = t; 361 if (l->cnt_max > dst->cnt_max) 362 dst->cnt_max = l->cnt_max; 363 if (l->cnt_wait_max > dst->cnt_wait_max) 364 dst->cnt_wait_max = l->cnt_wait_max; 365 dst->cnt_tot += l->cnt_tot; 366 dst->cnt_wait += l->cnt_wait; 367 dst->cnt_cur += l->cnt_cur; 368 dst->cnt_contest_locking += l->cnt_contest_locking; 369 } 370 } 371 372 } 373 374 static void 375 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 376 int t) 377 { 378 struct lock_prof *l; 379 int i; 380 381 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 382 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 383 struct lock_prof lp = {}; 384 385 if (l->ticks == t) 386 continue; 387 lock_prof_sum(l, &lp, i, spin, t); 388 lock_prof_output(&lp, sb); 389 if (sbuf_overflowed(sb)) 390 return; 391 } 392 } 393 } 394 395 static int 396 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 397 { 398 static int multiplier = 1; 399 struct sbuf *sb; 400 int error, cpu, t; 401 int enabled; 402 403 retry_sbufops: 404 sb = sbuf_new(NULL, NULL, LPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN); 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 lock_prof_idle(); 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 if (sbuf_overflowed(sb)) { 417 sbuf_delete(sb); 418 multiplier++; 419 goto retry_sbufops; 420 } 421 } 422 lock_prof_enable = enabled; 423 424 sbuf_finish(sb); 425 error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1); 426 sbuf_delete(sb); 427 return (error); 428 } 429 430 static int 431 enable_lock_prof(SYSCTL_HANDLER_ARGS) 432 { 433 int error, v; 434 435 v = lock_prof_enable; 436 error = sysctl_handle_int(oidp, &v, v, req); 437 if (error) 438 return (error); 439 if (req->newptr == NULL) 440 return (error); 441 if (v == lock_prof_enable) 442 return (0); 443 if (v == 1) 444 lock_prof_reset(); 445 lock_prof_enable = !!v; 446 447 return (0); 448 } 449 450 static int 451 reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) 452 { 453 int error, v; 454 455 v = 0; 456 error = sysctl_handle_int(oidp, &v, 0, req); 457 if (error) 458 return (error); 459 if (req->newptr == NULL) 460 return (error); 461 if (v == 0) 462 return (0); 463 lock_prof_reset(); 464 465 return (0); 466 } 467 468 static struct lock_prof * 469 lock_profile_lookup(struct lock_object *lo, int spin, const char *file, 470 int line) 471 { 472 const char *unknown = "(unknown)"; 473 struct lock_prof_type *type; 474 struct lock_prof *lp; 475 struct lphead *head; 476 const char *p; 477 u_int hash; 478 479 p = file; 480 if (p == NULL || *p == '\0') 481 p = unknown; 482 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; 483 hash &= LPROF_HASH_MASK; 484 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 485 head = &type->lpt_hash[hash]; 486 SLIST_FOREACH(lp, head, link) { 487 if (lp->line == line && lp->file == p && 488 lp->name == lo->lo_name) 489 return (lp); 490 491 } 492 lp = SLIST_FIRST(&type->lpt_lpalloc); 493 if (lp == NULL) { 494 lock_prof_rejected++; 495 return (lp); 496 } 497 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); 498 lp->file = p; 499 lp->line = line; 500 lp->class = LOCK_CLASS(lo); 501 lp->name = lo->lo_name; 502 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); 503 return (lp); 504 } 505 506 static struct lock_profile_object * 507 lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, 508 int line) 509 { 510 struct lock_profile_object *l; 511 struct lock_prof_type *type; 512 struct lpohead *head; 513 514 head = &curthread->td_lprof[spin]; 515 LIST_FOREACH(l, head, lpo_link) 516 if (l->lpo_obj == lo && l->lpo_file == file && 517 l->lpo_line == line) 518 return (l); 519 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 520 l = LIST_FIRST(&type->lpt_lpoalloc); 521 if (l == NULL) { 522 lock_prof_rejected++; 523 return (NULL); 524 } 525 LIST_REMOVE(l, lpo_link); 526 l->lpo_obj = lo; 527 l->lpo_file = file; 528 l->lpo_line = line; 529 l->lpo_cnt = 0; 530 LIST_INSERT_HEAD(head, l, lpo_link); 531 532 return (l); 533 } 534 535 void 536 lock_profile_obtain_lock_success(struct lock_object *lo, int contested, 537 uint64_t waittime, const char *file, int line) 538 { 539 static int lock_prof_count; 540 struct lock_profile_object *l; 541 int spin; 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 u_int64_t curtime, holdtime; 604 struct lpohead *head; 605 int spin; 606 607 if (lo->lo_flags & LO_NOPROFILE) 608 return; 609 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 610 head = &curthread->td_lprof[spin]; 611 if (LIST_FIRST(head) == NULL) 612 return; 613 critical_enter(); 614 /* Recheck enabled now that we're in a critical section. */ 615 if (lock_prof_enable == 0 && lock_prof_resetting == 1) 616 goto out; 617 /* 618 * If lock profiling is not enabled we still want to remove the 619 * lpo from our queue. 620 */ 621 LIST_FOREACH(l, head, lpo_link) 622 if (l->lpo_obj == lo) 623 break; 624 if (l == NULL) 625 goto out; 626 if (--l->lpo_ref > 0) 627 goto out; 628 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 629 if (lp == NULL) 630 goto release; 631 curtime = nanoseconds(); 632 if (curtime < l->lpo_acqtime) 633 goto release; 634 holdtime = curtime - l->lpo_acqtime; 635 636 /* 637 * Record if the lock has been held longer now than ever 638 * before. 639 */ 640 if (holdtime > lp->cnt_max) 641 lp->cnt_max = holdtime; 642 if (l->lpo_waittime > lp->cnt_wait_max) 643 lp->cnt_wait_max = l->lpo_waittime; 644 lp->cnt_tot += holdtime; 645 lp->cnt_wait += l->lpo_waittime; 646 lp->cnt_contest_locking += l->lpo_contest_locking; 647 lp->cnt_cur += l->lpo_cnt; 648 release: 649 LIST_REMOVE(l, lpo_link); 650 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin]; 651 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 652 out: 653 critical_exit(); 654 } 655 656 SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging"); 657 SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, "lock profiling"); 658 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 659 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 660 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW, 661 &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions."); 662 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 663 &lock_prof_rejected, 0, "Number of rejected profiling records"); 664 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, 665 NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics"); 666 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, 667 NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics"); 668 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, 669 NULL, 0, enable_lock_prof, "I", "Enable lock profiling"); 670 671 #endif
Cache object: 3ec08b9c2ed4eb92cdf51170023f7064
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