1/*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28/* 29 * This module holds the global variables and functions used to maintain 30 * lock_object structures. 31 */ 32 33#include <sys/cdefs.h> 34#include "opt_ddb.h" 35#include "opt_mprof.h" 36 37#include <sys/param.h> 38#include <sys/systm.h> 39#include <sys/kernel.h> 40#include <sys/ktr.h> 41#include <sys/limits.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/* 60 * Uncomment to validate that spin argument to acquire/release routines matches 61 * the flag in the lock 62 */ 63//#define LOCK_PROFILING_DEBUG_SPIN 64 65CTASSERT(LOCK_CLASS_MAX == 15); 66 67struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = { 68 &lock_class_mtx_spin, 69 &lock_class_mtx_sleep, 70 &lock_class_sx, 71 &lock_class_rm, 72 &lock_class_rm_sleepable, 73 &lock_class_rw, 74 &lock_class_lockmgr, 75}; 76 77void 78lock_init(struct lock_object *lock, struct lock_class *class, const char *name, 79 const char *type, int flags) 80{ 81 int i; 82 83 /* Check for double-init and zero object. */ 84 KASSERT(flags & LO_NEW || !lock_initialized(lock), 85 ("lock \"%s\" %p already initialized", name, lock)); 86 87 /* Look up lock class to find its index. */ 88 for (i = 0; i < LOCK_CLASS_MAX; i++) 89 if (lock_classes[i] == class) { 90 lock->lo_flags = i << LO_CLASSSHIFT; 91 break; 92 } 93 KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class)); 94 95 /* Initialize the lock object. */ 96 lock->lo_name = name; 97 lock->lo_flags |= flags | LO_INITIALIZED; 98 LOCK_LOG_INIT(lock, 0); 99 WITNESS_INIT(lock, (type != NULL) ? type : name); 100} 101 102void 103lock_destroy(struct lock_object *lock) 104{ 105 106 KASSERT(lock_initialized(lock), ("lock %p is not initialized", lock)); 107 WITNESS_DESTROY(lock); 108 LOCK_LOG_DESTROY(lock, 0); 109 lock->lo_flags &= ~LO_INITIALIZED; 110} 111 112static SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 113 "lock debugging"); 114static SYSCTL_NODE(_debug_lock, OID_AUTO, delay, 115 CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 116 "lock delay"); 117 118void 119lock_delay(struct lock_delay_arg *la) 120{ 121 struct lock_delay_config *lc = la->config; 122 u_int i; 123 124 for (i = la->delay; i > 0; i--) 125 cpu_spinwait(); 126 la->spin_cnt += la->delay; 127 128 la->delay <<= 1; 129 if (__predict_false(la->delay > (u_int)lc->max)) 130 la->delay = lc->max; 131} 132 133static u_int 134lock_roundup_2(u_int val) 135{ 136 u_int res; 137 138 for (res = 1; res <= val; res <<= 1) 139 continue; 140 141 return (res); 142} 143 144void 145lock_delay_default_init(struct lock_delay_config *lc) 146{ 147 148 lc->base = 1; 149 lc->max = min(lock_roundup_2(mp_ncpus) * 256, SHRT_MAX); 150} 151 152struct lock_delay_config __read_frequently locks_delay; 153u_short __read_frequently locks_delay_retries; 154u_short __read_frequently locks_delay_loops; 155 156SYSCTL_U16(_debug_lock, OID_AUTO, delay_base, CTLFLAG_RW, &locks_delay.base, 157 0, ""); 158SYSCTL_U16(_debug_lock, OID_AUTO, delay_max, CTLFLAG_RW, &locks_delay.max, 159 0, ""); 160SYSCTL_U16(_debug_lock, OID_AUTO, delay_retries, CTLFLAG_RW, &locks_delay_retries, 161 0, ""); 162SYSCTL_U16(_debug_lock, OID_AUTO, delay_loops, CTLFLAG_RW, &locks_delay_loops, 163 0, ""); 164 165static void 166locks_delay_init(void *arg __unused) 167{ 168 169 lock_delay_default_init(&locks_delay); 170 locks_delay_retries = 10; 171 locks_delay_loops = max(10000, locks_delay.max); 172} 173LOCK_DELAY_SYSINIT(locks_delay_init); 174 175#ifdef DDB 176DB_SHOW_COMMAND(lock, db_show_lock) 177{ 178 struct lock_object *lock; 179 struct lock_class *class; 180 181 if (!have_addr) 182 return; 183 lock = (struct lock_object *)addr; 184 if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) { 185 db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock)); 186 return; 187 } 188 class = LOCK_CLASS(lock); 189 db_printf(" class: %s\n", class->lc_name); 190 db_printf(" name: %s\n", lock->lo_name); 191 class->lc_ddb_show(lock); 192} 193#endif 194 195#ifdef LOCK_PROFILING 196 197/* 198 * One object per-thread for each lock the thread owns. Tracks individual 199 * lock instances. 200 */ 201struct lock_profile_object { 202 LIST_ENTRY(lock_profile_object) lpo_link; 203 struct lock_object *lpo_obj; 204 const char *lpo_file; 205 int lpo_line; 206 uint16_t lpo_ref; 207 uint16_t lpo_cnt; 208 uint64_t lpo_acqtime; 209 uint64_t lpo_waittime; 210 u_int lpo_contest_locking; 211}; 212 213/* 214 * One lock_prof for each (file, line, lock object) triple. 215 */ 216struct lock_prof { 217 SLIST_ENTRY(lock_prof) link; 218 struct lock_class *class; 219 const char *file; 220 const char *name; 221 int line; 222 int ticks; 223 uintmax_t cnt_wait_max; 224 uintmax_t cnt_max; 225 uintmax_t cnt_tot; 226 uintmax_t cnt_wait; 227 uintmax_t cnt_cur; 228 uintmax_t cnt_contest_locking; 229}; 230 231SLIST_HEAD(lphead, lock_prof); 232 233#define LPROF_HASH_SIZE 4096 234#define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1) 235#define LPROF_CACHE_SIZE 4096 236 237/* 238 * Array of objects and profs for each type of object for each cpu. Spinlocks 239 * are handled separately because a thread may be preempted and acquire a 240 * spinlock while in the lock profiling code of a non-spinlock. In this way 241 * we only need a critical section to protect the per-cpu lists. 242 */ 243struct lock_prof_type { 244 struct lphead lpt_lpalloc; 245 struct lpohead lpt_lpoalloc; 246 struct lphead lpt_hash[LPROF_HASH_SIZE]; 247 struct lock_prof lpt_prof[LPROF_CACHE_SIZE]; 248 struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE]; 249}; 250 251struct lock_prof_cpu { 252 struct lock_prof_type lpc_types[2]; /* One for spin one for other. */ 253}; 254 255DPCPU_DEFINE_STATIC(struct lock_prof_cpu, lp); 256#define LP_CPU_SELF (DPCPU_PTR(lp)) 257#define LP_CPU(cpu) (DPCPU_ID_PTR((cpu), lp)) 258 259volatile int __read_mostly lock_prof_enable; 260int __read_mostly lock_contested_only; 261static volatile int lock_prof_resetting; 262 263#define LPROF_SBUF_SIZE 256 264 265static int lock_prof_rejected; 266static int lock_prof_skipspin; 267 268#ifndef USE_CPU_NANOSECONDS 269uint64_t 270nanoseconds(void) 271{ 272 struct bintime bt; 273 uint64_t ns; 274 275 binuptime(&bt); 276 /* From bintime2timespec */ 277 ns = bt.sec * (uint64_t)1000000000; 278 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; 279 return (ns); 280} 281#endif 282 283static void 284lock_prof_init_type(struct lock_prof_type *type) 285{ 286 int i; 287 288 SLIST_INIT(&type->lpt_lpalloc); 289 LIST_INIT(&type->lpt_lpoalloc); 290 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 291 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], 292 link); 293 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], 294 lpo_link); 295 } 296} 297 298static void 299lock_prof_init(void *arg) 300{ 301 int cpu; 302 303 CPU_FOREACH(cpu) { 304 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[0]); 305 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[1]); 306 } 307} 308SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); 309 310static void 311lock_prof_reset_wait(void) 312{ 313 314 /* 315 * Spin relinquishing our cpu so that quiesce_all_cpus may 316 * complete. 317 */ 318 while (lock_prof_resetting) 319 sched_relinquish(curthread); 320} 321 322static void 323lock_prof_reset(void) 324{ 325 struct lock_prof_cpu *lpc; 326 int enabled, i, cpu; 327 328 /* 329 * We not only race with acquiring and releasing locks but also 330 * thread exit. To be certain that threads exit without valid head 331 * pointers they must see resetting set before enabled is cleared. 332 * Otherwise a lock may not be removed from a per-thread list due 333 * to disabled being set but not wait for reset() to remove it below. 334 */ 335 atomic_store_rel_int(&lock_prof_resetting, 1); 336 enabled = lock_prof_enable; 337 lock_prof_enable = 0; 338 /* 339 * This both publishes lock_prof_enable as disabled and makes sure 340 * everyone else reads it if they are not far enough. We wait for the 341 * rest down below. 342 */ 343 cpus_fence_seq_cst(); 344 quiesce_all_critical(); 345 /* 346 * Some objects may have migrated between CPUs. Clear all links 347 * before we zero the structures. Some items may still be linked 348 * into per-thread lists as well. 349 */ 350 CPU_FOREACH(cpu) { 351 lpc = LP_CPU(cpu); 352 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 353 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 354 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 355 } 356 } 357 CPU_FOREACH(cpu) { 358 lpc = LP_CPU(cpu); 359 bzero(lpc, sizeof(*lpc)); 360 lock_prof_init_type(&lpc->lpc_types[0]); 361 lock_prof_init_type(&lpc->lpc_types[1]); 362 } 363 /* 364 * Paired with the fence from cpus_fence_seq_cst() 365 */ 366 atomic_store_rel_int(&lock_prof_resetting, 0); 367 lock_prof_enable = enabled; 368} 369 370static void 371lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 372{ 373 const char *p; 374 375 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 376 sbuf_printf(sb, 377 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", 378 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, 379 lp->cnt_wait / 1000, lp->cnt_cur, 380 lp->cnt_cur == 0 ? (uintmax_t)0 : 381 lp->cnt_tot / (lp->cnt_cur * 1000), 382 lp->cnt_cur == 0 ? (uintmax_t)0 : 383 lp->cnt_wait / (lp->cnt_cur * 1000), 384 (uintmax_t)0, lp->cnt_contest_locking, 385 p, lp->line, lp->class->lc_name, lp->name); 386} 387 388static void 389lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 390 int spin, int t) 391{ 392 struct lock_prof_type *type; 393 struct lock_prof *l; 394 int cpu; 395 396 dst->file = match->file; 397 dst->line = match->line; 398 dst->class = match->class; 399 dst->name = match->name; 400 401 CPU_FOREACH(cpu) { 402 type = &LP_CPU(cpu)->lpc_types[spin]; 403 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 404 if (l->ticks == t) 405 continue; 406 if (l->file != match->file || l->line != match->line || 407 l->name != match->name) 408 continue; 409 l->ticks = t; 410 if (l->cnt_max > dst->cnt_max) 411 dst->cnt_max = l->cnt_max; 412 if (l->cnt_wait_max > dst->cnt_wait_max) 413 dst->cnt_wait_max = l->cnt_wait_max; 414 dst->cnt_tot += l->cnt_tot; 415 dst->cnt_wait += l->cnt_wait; 416 dst->cnt_cur += l->cnt_cur; 417 dst->cnt_contest_locking += l->cnt_contest_locking; 418 } 419 } 420} 421 422static void 423lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 424 int t) 425{ 426 struct lock_prof *l; 427 int i; 428 429 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 430 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 431 struct lock_prof lp = {}; 432 433 if (l->ticks == t) 434 continue; 435 lock_prof_sum(l, &lp, i, spin, t); 436 lock_prof_output(&lp, sb); 437 } 438 } 439} 440 441static int 442dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 443{ 444 struct sbuf *sb; 445 int error, cpu, t; 446 int enabled; 447 448 error = sysctl_wire_old_buffer(req, 0); 449 if (error != 0) 450 return (error); 451 sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req); 452 sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n", 453 "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); 454 enabled = lock_prof_enable; 455 lock_prof_enable = 0; 456 /* 457 * See the comment in lock_prof_reset 458 */ 459 cpus_fence_seq_cst(); 460 quiesce_all_critical(); 461 t = ticks; 462 CPU_FOREACH(cpu) { 463 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[0], sb, 0, t); 464 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[1], sb, 1, t); 465 } 466 atomic_thread_fence_rel(); 467 lock_prof_enable = enabled; 468 469 error = sbuf_finish(sb); 470 /* Output a trailing NUL. */ 471 if (error == 0) 472 error = SYSCTL_OUT(req, "", 1); 473 sbuf_delete(sb); 474 return (error); 475} 476 477static int 478enable_lock_prof(SYSCTL_HANDLER_ARGS) 479{ 480 int error, v; 481 482 v = lock_prof_enable; 483 error = sysctl_handle_int(oidp, &v, v, req); 484 if (error) 485 return (error); 486 if (req->newptr == NULL) 487 return (error); 488 if (v == lock_prof_enable) 489 return (0); 490 if (v == 1) 491 lock_prof_reset(); 492 lock_prof_enable = !!v; 493 494 return (0); 495} 496 497static int 498reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) 499{ 500 int error, v; 501 502 v = 0; 503 error = sysctl_handle_int(oidp, &v, 0, req); 504 if (error) 505 return (error); 506 if (req->newptr == NULL) 507 return (error); 508 if (v == 0) 509 return (0); 510 lock_prof_reset(); 511 512 return (0); 513} 514 515static struct lock_prof * 516lock_profile_lookup(struct lock_object *lo, int spin, const char *file, 517 int line) 518{ 519 const char *unknown = "(unknown)"; 520 struct lock_prof_type *type; 521 struct lock_prof *lp; 522 struct lphead *head; 523 const char *p; 524 u_int hash; 525 526 p = file; 527 if (p == NULL || *p == '\0') 528 p = unknown; 529 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; 530 hash &= LPROF_HASH_MASK; 531 type = &LP_CPU_SELF->lpc_types[spin]; 532 head = &type->lpt_hash[hash]; 533 SLIST_FOREACH(lp, head, link) { 534 if (lp->line == line && lp->file == p && 535 lp->name == lo->lo_name) 536 return (lp); 537 } 538 lp = SLIST_FIRST(&type->lpt_lpalloc); 539 if (lp == NULL) { 540 lock_prof_rejected++; 541 return (lp); 542 } 543 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); 544 lp->file = p; 545 lp->line = line; 546 lp->class = LOCK_CLASS(lo); 547 lp->name = lo->lo_name; 548 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); 549 return (lp); 550} 551 552static struct lock_profile_object * 553lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, 554 int line) 555{ 556 struct lock_profile_object *l; 557 struct lock_prof_type *type; 558 struct lpohead *head; 559 560 head = &curthread->td_lprof[spin]; 561 LIST_FOREACH(l, head, lpo_link) 562 if (l->lpo_obj == lo && l->lpo_file == file && 563 l->lpo_line == line) 564 return (l); 565 type = &LP_CPU_SELF->lpc_types[spin]; 566 l = LIST_FIRST(&type->lpt_lpoalloc); 567 if (l == NULL) { 568 lock_prof_rejected++; 569 return (NULL); 570 } 571 LIST_REMOVE(l, lpo_link); 572 l->lpo_obj = lo; 573 l->lpo_file = file; 574 l->lpo_line = line; 575 l->lpo_cnt = 0; 576 LIST_INSERT_HEAD(head, l, lpo_link); 577 578 return (l); 579} 580 581void 582lock_profile_obtain_lock_success(struct lock_object *lo, bool spin, 583 int contested, uint64_t waittime, const char *file, int line) 584{ 585 struct lock_profile_object *l; 586 587#ifdef LOCK_PROFILING_DEBUG_SPIN 588 bool is_spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK); 589 if ((spin && !is_spin) || (!spin && is_spin)) 590 printf("%s: lock %s spin mismatch (arg %d, flag %d)\n", __func__, 591 lo->lo_name, spin, is_spin); 592#endif 593 594 /* don't reset the timer when/if recursing */ 595 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 596 return; 597 if (lock_contested_only && !contested) 598 return; 599 if (spin && lock_prof_skipspin == 1) 600 return; 601 602 if (SCHEDULER_STOPPED()) 603 return; 604 605 critical_enter(); 606 /* Recheck enabled now that we're in a critical section. */ 607 if (lock_prof_enable == 0) 608 goto out; 609 l = lock_profile_object_lookup(lo, spin, file, line); 610 if (l == NULL) 611 goto out; 612 l->lpo_cnt++; 613 if (++l->lpo_ref > 1) 614 goto out; 615 l->lpo_contest_locking = contested; 616 l->lpo_acqtime = nanoseconds(); 617 if (waittime && (l->lpo_acqtime > waittime)) 618 l->lpo_waittime = l->lpo_acqtime - waittime; 619 else 620 l->lpo_waittime = 0; 621out: 622 /* 623 * Paired with cpus_fence_seq_cst(). 624 */ 625 atomic_thread_fence_rel(); 626 critical_exit(); 627} 628 629void 630lock_profile_thread_exit(struct thread *td) 631{ 632#ifdef INVARIANTS 633 struct lock_profile_object *l; 634 635 MPASS(curthread->td_critnest == 0); 636#endif 637 /* 638 * If lock profiling was disabled we have to wait for reset to 639 * clear our pointers before we can exit safely. 640 */ 641 lock_prof_reset_wait(); 642#ifdef INVARIANTS 643 LIST_FOREACH(l, &td->td_lprof[0], lpo_link) 644 printf("thread still holds lock acquired at %s:%d\n", 645 l->lpo_file, l->lpo_line); 646 LIST_FOREACH(l, &td->td_lprof[1], lpo_link) 647 printf("thread still holds lock acquired at %s:%d\n", 648 l->lpo_file, l->lpo_line); 649#endif 650 MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL); 651 MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL); 652} 653 654void 655lock_profile_release_lock(struct lock_object *lo, bool spin) 656{ 657 struct lock_profile_object *l; 658 struct lock_prof_type *type; 659 struct lock_prof *lp; 660 uint64_t curtime, holdtime; 661 struct lpohead *head; 662 663#ifdef LOCK_PROFILING_DEBUG_SPIN 664 bool is_spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK); 665 if ((spin && !is_spin) || (!spin && is_spin)) 666 printf("%s: lock %s spin mismatch (arg %d, flag %d)\n", __func__, 667 lo->lo_name, spin, is_spin); 668#endif 669 670 if (lo->lo_flags & LO_NOPROFILE) 671 return; 672 head = &curthread->td_lprof[spin]; 673 if (LIST_FIRST(head) == NULL) 674 return; 675 if (SCHEDULER_STOPPED()) 676 return; 677 critical_enter(); 678 /* Recheck enabled now that we're in a critical section. */ 679 if (lock_prof_enable == 0 && lock_prof_resetting == 1) 680 goto out; 681 /* 682 * If lock profiling is not enabled we still want to remove the 683 * lpo from our queue. 684 */ 685 LIST_FOREACH(l, head, lpo_link) 686 if (l->lpo_obj == lo) 687 break; 688 if (l == NULL) 689 goto out; 690 if (--l->lpo_ref > 0) 691 goto out; 692 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 693 if (lp == NULL) 694 goto release; 695 curtime = nanoseconds(); 696 if (curtime < l->lpo_acqtime) 697 goto release; 698 holdtime = curtime - l->lpo_acqtime; 699 700 /* 701 * Record if the lock has been held longer now than ever 702 * before. 703 */ 704 if (holdtime > lp->cnt_max) 705 lp->cnt_max = holdtime; 706 if (l->lpo_waittime > lp->cnt_wait_max) 707 lp->cnt_wait_max = l->lpo_waittime; 708 lp->cnt_tot += holdtime; 709 lp->cnt_wait += l->lpo_waittime; 710 lp->cnt_contest_locking += l->lpo_contest_locking; 711 lp->cnt_cur += l->lpo_cnt; 712release: 713 LIST_REMOVE(l, lpo_link); 714 type = &LP_CPU_SELF->lpc_types[spin]; 715 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 716out: 717 /* 718 * Paired with cpus_fence_seq_cst(). 719 */ 720 atomic_thread_fence_rel(); 721 critical_exit(); 722} 723 724static SYSCTL_NODE(_debug_lock, OID_AUTO, prof, 725 CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 726 "lock profiling"); 727SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 728 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 729SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 730 &lock_prof_rejected, 0, "Number of rejected profiling records"); 731SYSCTL_INT(_debug_lock_prof, OID_AUTO, contested_only, CTLFLAG_RW, 732 &lock_contested_only, 0, "Only profile contested acquires"); 733SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, 734 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, 735 dump_lock_prof_stats, "A", 736 "Lock profiling statistics"); 737SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, 738 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0, 739 reset_lock_prof_stats, "I", 740 "Reset lock profiling statistics"); 741SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, 742 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, 743 enable_lock_prof, "I", 744 "Enable lock profiling"); 745 746#endif 747