1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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 __FBSDID("$FreeBSD$"); 35 36 #include "opt_ddb.h" 37 #include "opt_mprof.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/kernel.h> 42 #include <sys/ktr.h> 43 #include <sys/lock.h> 44 #include <sys/lock_profile.h> 45 #include <sys/malloc.h> 46 #include <sys/mutex.h> 47 #include <sys/pcpu.h> 48 #include <sys/proc.h> 49 #include <sys/sbuf.h> 50 #include <sys/sched.h> 51 #include <sys/smp.h> 52 #include <sys/sysctl.h> 53 54 #ifdef DDB 55 #include <ddb/ddb.h> 56 #endif 57 58 #include <machine/cpufunc.h> 59 60 SDT_PROVIDER_DEFINE(lock); 61 SDT_PROBE_DEFINE1(lock, , , starvation, "u_int"); 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_rm_sleepable, 71 &lock_class_rw, 72 &lock_class_lockmgr, 73 }; 74 75 void 76 lock_init(struct lock_object *lock, struct lock_class *class, const char *name, 77 const char *type, int flags) 78 { 79 int i; 80 81 /* Check for double-init and zero object. */ 82 KASSERT(flags & LO_NEW || !lock_initialized(lock), 83 ("lock \"%s\" %p already initialized", name, lock)); 84 85 /* Look up lock class to find its index. */ 86 for (i = 0; i < LOCK_CLASS_MAX; i++) 87 if (lock_classes[i] == class) { 88 lock->lo_flags = i << LO_CLASSSHIFT; 89 break; 90 } 91 KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class)); 92 93 /* Initialize the lock object. */ 94 lock->lo_name = name; 95 lock->lo_flags |= flags | LO_INITIALIZED; 96 LOCK_LOG_INIT(lock, 0); 97 WITNESS_INIT(lock, (type != NULL) ? type : name); 98 } 99 100 void 101 lock_destroy(struct lock_object *lock) 102 { 103 104 KASSERT(lock_initialized(lock), ("lock %p is not initialized", lock)); 105 WITNESS_DESTROY(lock); 106 LOCK_LOG_DESTROY(lock, 0); 107 lock->lo_flags &= ~LO_INITIALIZED; 108 } 109 110 static SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging"); 111 static SYSCTL_NODE(_debug_lock, OID_AUTO, delay, CTLFLAG_RD, NULL, 112 "lock delay"); 113 114 static u_int __read_mostly starvation_limit = 131072; 115 SYSCTL_INT(_debug_lock_delay, OID_AUTO, starvation_limit, CTLFLAG_RW, 116 &starvation_limit, 0, ""); 117 118 static u_int __read_mostly restrict_starvation = 0; 119 SYSCTL_INT(_debug_lock_delay, OID_AUTO, restrict_starvation, CTLFLAG_RW, 120 &restrict_starvation, 0, ""); 121 122 void 123 lock_delay(struct lock_delay_arg *la) 124 { 125 struct lock_delay_config *lc = la->config; 126 u_short i; 127 128 la->delay <<= 1; 129 if (__predict_false(la->delay > lc->max)) 130 la->delay = lc->max; 131 132 for (i = la->delay; i > 0; i--) 133 cpu_spinwait(); 134 135 la->spin_cnt += la->delay; 136 if (__predict_false(la->spin_cnt > starvation_limit)) { 137 SDT_PROBE1(lock, , , starvation, la->delay); 138 if (restrict_starvation) 139 la->delay = lc->base; 140 } 141 } 142 143 static u_int 144 lock_roundup_2(u_int val) 145 { 146 u_int res; 147 148 for (res = 1; res <= val; res <<= 1) 149 continue; 150 151 return (res); 152 } 153 154 void 155 lock_delay_default_init(struct lock_delay_config *lc) 156 { 157 158 lc->base = 1; 159 lc->max = lock_roundup_2(mp_ncpus) * 256; 160 if (lc->max > 32678) 161 lc->max = 32678; 162 } 163 164 struct lock_delay_config __read_frequently locks_delay; 165 u_short __read_frequently locks_delay_retries; 166 u_short __read_frequently locks_delay_loops; 167 168 SYSCTL_U16(_debug_lock, OID_AUTO, delay_base, CTLFLAG_RW, &locks_delay.base, 169 0, ""); 170 SYSCTL_U16(_debug_lock, OID_AUTO, delay_max, CTLFLAG_RW, &locks_delay.max, 171 0, ""); 172 SYSCTL_U16(_debug_lock, OID_AUTO, delay_retries, CTLFLAG_RW, &locks_delay_retries, 173 0, ""); 174 SYSCTL_U16(_debug_lock, OID_AUTO, delay_loops, CTLFLAG_RW, &locks_delay_loops, 175 0, ""); 176 177 static void 178 locks_delay_init(void *arg __unused) 179 { 180 181 lock_delay_default_init(&locks_delay); 182 locks_delay_retries = 10; 183 locks_delay_loops = max(10000, locks_delay.max); 184 } 185 LOCK_DELAY_SYSINIT(locks_delay_init); 186 187 #ifdef DDB 188 DB_SHOW_COMMAND(lock, db_show_lock) 189 { 190 struct lock_object *lock; 191 struct lock_class *class; 192 193 if (!have_addr) 194 return; 195 lock = (struct lock_object *)addr; 196 if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) { 197 db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock)); 198 return; 199 } 200 class = LOCK_CLASS(lock); 201 db_printf(" class: %s\n", class->lc_name); 202 db_printf(" name: %s\n", lock->lo_name); 203 class->lc_ddb_show(lock); 204 } 205 #endif 206 207 #ifdef LOCK_PROFILING 208 209 /* 210 * One object per-thread for each lock the thread owns. Tracks individual 211 * lock instances. 212 */ 213 struct lock_profile_object { 214 LIST_ENTRY(lock_profile_object) lpo_link; 215 struct lock_object *lpo_obj; 216 const char *lpo_file; 217 int lpo_line; 218 uint16_t lpo_ref; 219 uint16_t lpo_cnt; 220 uint64_t lpo_acqtime; 221 uint64_t lpo_waittime; 222 u_int lpo_contest_locking; 223 }; 224 225 /* 226 * One lock_prof for each (file, line, lock object) triple. 227 */ 228 struct lock_prof { 229 SLIST_ENTRY(lock_prof) link; 230 struct lock_class *class; 231 const char *file; 232 const char *name; 233 int line; 234 int ticks; 235 uintmax_t cnt_wait_max; 236 uintmax_t cnt_max; 237 uintmax_t cnt_tot; 238 uintmax_t cnt_wait; 239 uintmax_t cnt_cur; 240 uintmax_t cnt_contest_locking; 241 }; 242 243 SLIST_HEAD(lphead, lock_prof); 244 245 #define LPROF_HASH_SIZE 4096 246 #define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1) 247 #define LPROF_CACHE_SIZE 4096 248 249 /* 250 * Array of objects and profs for each type of object for each cpu. Spinlocks 251 * are handled separately because a thread may be preempted and acquire a 252 * spinlock while in the lock profiling code of a non-spinlock. In this way 253 * we only need a critical section to protect the per-cpu lists. 254 */ 255 struct lock_prof_type { 256 struct lphead lpt_lpalloc; 257 struct lpohead lpt_lpoalloc; 258 struct lphead lpt_hash[LPROF_HASH_SIZE]; 259 struct lock_prof lpt_prof[LPROF_CACHE_SIZE]; 260 struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE]; 261 }; 262 263 struct lock_prof_cpu { 264 struct lock_prof_type lpc_types[2]; /* One for spin one for other. */ 265 }; 266 267 DPCPU_DEFINE_STATIC(struct lock_prof_cpu, lp); 268 #define LP_CPU_SELF (DPCPU_PTR(lp)) 269 #define LP_CPU(cpu) (DPCPU_ID_PTR((cpu), lp)) 270 271 volatile int __read_mostly lock_prof_enable; 272 static volatile int lock_prof_resetting; 273 274 #define LPROF_SBUF_SIZE 256 275 276 static int lock_prof_rejected; 277 static int lock_prof_skipspin; 278 static int lock_prof_skipcount; 279 280 #ifndef USE_CPU_NANOSECONDS 281 uint64_t 282 nanoseconds(void) 283 { 284 struct bintime bt; 285 uint64_t ns; 286 287 binuptime(&bt); 288 /* From bintime2timespec */ 289 ns = bt.sec * (uint64_t)1000000000; 290 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; 291 return (ns); 292 } 293 #endif 294 295 static void 296 lock_prof_init_type(struct lock_prof_type *type) 297 { 298 int i; 299 300 SLIST_INIT(&type->lpt_lpalloc); 301 LIST_INIT(&type->lpt_lpoalloc); 302 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 303 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], 304 link); 305 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], 306 lpo_link); 307 } 308 } 309 310 static void 311 lock_prof_init(void *arg) 312 { 313 int cpu; 314 315 CPU_FOREACH(cpu) { 316 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[0]); 317 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[1]); 318 } 319 } 320 SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); 321 322 static void 323 lock_prof_reset_wait(void) 324 { 325 326 /* 327 * Spin relinquishing our cpu so that quiesce_all_cpus may 328 * complete. 329 */ 330 while (lock_prof_resetting) 331 sched_relinquish(curthread); 332 } 333 334 static void 335 lock_prof_reset(void) 336 { 337 struct lock_prof_cpu *lpc; 338 int enabled, i, cpu; 339 340 /* 341 * We not only race with acquiring and releasing locks but also 342 * thread exit. To be certain that threads exit without valid head 343 * pointers they must see resetting set before enabled is cleared. 344 * Otherwise a lock may not be removed from a per-thread list due 345 * to disabled being set but not wait for reset() to remove it below. 346 */ 347 atomic_store_rel_int(&lock_prof_resetting, 1); 348 enabled = lock_prof_enable; 349 lock_prof_enable = 0; 350 /* 351 * This both publishes lock_prof_enable as disabled and makes sure 352 * everyone else reads it if they are not far enough. We wait for the 353 * rest down below. 354 */ 355 cpus_fence_seq_cst(); 356 quiesce_all_critical(); 357 /* 358 * Some objects may have migrated between CPUs. Clear all links 359 * before we zero the structures. Some items may still be linked 360 * into per-thread lists as well. 361 */ 362 CPU_FOREACH(cpu) { 363 lpc = LP_CPU(cpu); 364 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 365 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 366 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 367 } 368 } 369 CPU_FOREACH(cpu) { 370 lpc = LP_CPU(cpu); 371 bzero(lpc, sizeof(*lpc)); 372 lock_prof_init_type(&lpc->lpc_types[0]); 373 lock_prof_init_type(&lpc->lpc_types[1]); 374 } 375 /* 376 * Paired with the fence from cpus_fence_seq_cst() 377 */ 378 atomic_store_rel_int(&lock_prof_resetting, 0); 379 lock_prof_enable = enabled; 380 } 381 382 static void 383 lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 384 { 385 const char *p; 386 387 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 388 sbuf_printf(sb, 389 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", 390 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, 391 lp->cnt_wait / 1000, lp->cnt_cur, 392 lp->cnt_cur == 0 ? (uintmax_t)0 : 393 lp->cnt_tot / (lp->cnt_cur * 1000), 394 lp->cnt_cur == 0 ? (uintmax_t)0 : 395 lp->cnt_wait / (lp->cnt_cur * 1000), 396 (uintmax_t)0, lp->cnt_contest_locking, 397 p, lp->line, lp->class->lc_name, lp->name); 398 } 399 400 static void 401 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 402 int spin, int t) 403 { 404 struct lock_prof_type *type; 405 struct lock_prof *l; 406 int cpu; 407 408 dst->file = match->file; 409 dst->line = match->line; 410 dst->class = match->class; 411 dst->name = match->name; 412 413 CPU_FOREACH(cpu) { 414 type = &LP_CPU(cpu)->lpc_types[spin]; 415 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 416 if (l->ticks == t) 417 continue; 418 if (l->file != match->file || l->line != match->line || 419 l->name != match->name) 420 continue; 421 l->ticks = t; 422 if (l->cnt_max > dst->cnt_max) 423 dst->cnt_max = l->cnt_max; 424 if (l->cnt_wait_max > dst->cnt_wait_max) 425 dst->cnt_wait_max = l->cnt_wait_max; 426 dst->cnt_tot += l->cnt_tot; 427 dst->cnt_wait += l->cnt_wait; 428 dst->cnt_cur += l->cnt_cur; 429 dst->cnt_contest_locking += l->cnt_contest_locking; 430 } 431 } 432 } 433 434 static void 435 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 436 int t) 437 { 438 struct lock_prof *l; 439 int i; 440 441 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 442 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 443 struct lock_prof lp = {}; 444 445 if (l->ticks == t) 446 continue; 447 lock_prof_sum(l, &lp, i, spin, t); 448 lock_prof_output(&lp, sb); 449 } 450 } 451 } 452 453 static int 454 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 455 { 456 struct sbuf *sb; 457 int error, cpu, t; 458 int enabled; 459 460 error = sysctl_wire_old_buffer(req, 0); 461 if (error != 0) 462 return (error); 463 sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req); 464 sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n", 465 "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); 466 enabled = lock_prof_enable; 467 lock_prof_enable = 0; 468 /* 469 * See the comment in lock_prof_reset 470 */ 471 cpus_fence_seq_cst(); 472 quiesce_all_critical(); 473 t = ticks; 474 CPU_FOREACH(cpu) { 475 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[0], sb, 0, t); 476 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[1], sb, 1, t); 477 } 478 atomic_thread_fence_rel(); 479 lock_prof_enable = enabled; 480 481 error = sbuf_finish(sb); 482 /* Output a trailing NUL. */ 483 if (error == 0) 484 error = SYSCTL_OUT(req, "", 1); 485 sbuf_delete(sb); 486 return (error); 487 } 488 489 static int 490 enable_lock_prof(SYSCTL_HANDLER_ARGS) 491 { 492 int error, v; 493 494 v = lock_prof_enable; 495 error = sysctl_handle_int(oidp, &v, v, req); 496 if (error) 497 return (error); 498 if (req->newptr == NULL) 499 return (error); 500 if (v == lock_prof_enable) 501 return (0); 502 if (v == 1) 503 lock_prof_reset(); 504 lock_prof_enable = !!v; 505 506 return (0); 507 } 508 509 static int 510 reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) 511 { 512 int error, v; 513 514 v = 0; 515 error = sysctl_handle_int(oidp, &v, 0, req); 516 if (error) 517 return (error); 518 if (req->newptr == NULL) 519 return (error); 520 if (v == 0) 521 return (0); 522 lock_prof_reset(); 523 524 return (0); 525 } 526 527 static struct lock_prof * 528 lock_profile_lookup(struct lock_object *lo, int spin, const char *file, 529 int line) 530 { 531 const char *unknown = "(unknown)"; 532 struct lock_prof_type *type; 533 struct lock_prof *lp; 534 struct lphead *head; 535 const char *p; 536 u_int hash; 537 538 p = file; 539 if (p == NULL || *p == '\0') 540 p = unknown; 541 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; 542 hash &= LPROF_HASH_MASK; 543 type = &LP_CPU_SELF->lpc_types[spin]; 544 head = &type->lpt_hash[hash]; 545 SLIST_FOREACH(lp, head, link) { 546 if (lp->line == line && lp->file == p && 547 lp->name == lo->lo_name) 548 return (lp); 549 550 } 551 lp = SLIST_FIRST(&type->lpt_lpalloc); 552 if (lp == NULL) { 553 lock_prof_rejected++; 554 return (lp); 555 } 556 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); 557 lp->file = p; 558 lp->line = line; 559 lp->class = LOCK_CLASS(lo); 560 lp->name = lo->lo_name; 561 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); 562 return (lp); 563 } 564 565 static struct lock_profile_object * 566 lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, 567 int line) 568 { 569 struct lock_profile_object *l; 570 struct lock_prof_type *type; 571 struct lpohead *head; 572 573 head = &curthread->td_lprof[spin]; 574 LIST_FOREACH(l, head, lpo_link) 575 if (l->lpo_obj == lo && l->lpo_file == file && 576 l->lpo_line == line) 577 return (l); 578 type = &LP_CPU_SELF->lpc_types[spin]; 579 l = LIST_FIRST(&type->lpt_lpoalloc); 580 if (l == NULL) { 581 lock_prof_rejected++; 582 return (NULL); 583 } 584 LIST_REMOVE(l, lpo_link); 585 l->lpo_obj = lo; 586 l->lpo_file = file; 587 l->lpo_line = line; 588 l->lpo_cnt = 0; 589 LIST_INSERT_HEAD(head, l, lpo_link); 590 591 return (l); 592 } 593 594 void 595 lock_profile_obtain_lock_success(struct lock_object *lo, int contested, 596 uint64_t waittime, const char *file, int line) 597 { 598 static int lock_prof_count; 599 struct lock_profile_object *l; 600 int spin; 601 602 if (SCHEDULER_STOPPED()) 603 return; 604 605 /* don't reset the timer when/if recursing */ 606 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 607 return; 608 if (lock_prof_skipcount && 609 (++lock_prof_count % lock_prof_skipcount) != 0) 610 return; 611 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 612 if (spin && lock_prof_skipspin == 1) 613 return; 614 critical_enter(); 615 /* Recheck enabled now that we're in a critical section. */ 616 if (lock_prof_enable == 0) 617 goto out; 618 l = lock_profile_object_lookup(lo, spin, file, line); 619 if (l == NULL) 620 goto out; 621 l->lpo_cnt++; 622 if (++l->lpo_ref > 1) 623 goto out; 624 l->lpo_contest_locking = contested; 625 l->lpo_acqtime = nanoseconds(); 626 if (waittime && (l->lpo_acqtime > waittime)) 627 l->lpo_waittime = l->lpo_acqtime - waittime; 628 else 629 l->lpo_waittime = 0; 630 out: 631 /* 632 * Paired with cpus_fence_seq_cst(). 633 */ 634 atomic_thread_fence_rel(); 635 critical_exit(); 636 } 637 638 void 639 lock_profile_thread_exit(struct thread *td) 640 { 641 #ifdef INVARIANTS 642 struct lock_profile_object *l; 643 644 MPASS(curthread->td_critnest == 0); 645 #endif 646 /* 647 * If lock profiling was disabled we have to wait for reset to 648 * clear our pointers before we can exit safely. 649 */ 650 lock_prof_reset_wait(); 651 #ifdef INVARIANTS 652 LIST_FOREACH(l, &td->td_lprof[0], lpo_link) 653 printf("thread still holds lock acquired at %s:%d\n", 654 l->lpo_file, l->lpo_line); 655 LIST_FOREACH(l, &td->td_lprof[1], lpo_link) 656 printf("thread still holds lock acquired at %s:%d\n", 657 l->lpo_file, l->lpo_line); 658 #endif 659 MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL); 660 MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL); 661 } 662 663 void 664 lock_profile_release_lock(struct lock_object *lo) 665 { 666 struct lock_profile_object *l; 667 struct lock_prof_type *type; 668 struct lock_prof *lp; 669 uint64_t curtime, holdtime; 670 struct lpohead *head; 671 int spin; 672 673 if (SCHEDULER_STOPPED()) 674 return; 675 if (lo->lo_flags & LO_NOPROFILE) 676 return; 677 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 678 head = &curthread->td_lprof[spin]; 679 if (LIST_FIRST(head) == NULL) 680 return; 681 critical_enter(); 682 /* Recheck enabled now that we're in a critical section. */ 683 if (lock_prof_enable == 0 && lock_prof_resetting == 1) 684 goto out; 685 /* 686 * If lock profiling is not enabled we still want to remove the 687 * lpo from our queue. 688 */ 689 LIST_FOREACH(l, head, lpo_link) 690 if (l->lpo_obj == lo) 691 break; 692 if (l == NULL) 693 goto out; 694 if (--l->lpo_ref > 0) 695 goto out; 696 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 697 if (lp == NULL) 698 goto release; 699 curtime = nanoseconds(); 700 if (curtime < l->lpo_acqtime) 701 goto release; 702 holdtime = curtime - l->lpo_acqtime; 703 704 /* 705 * Record if the lock has been held longer now than ever 706 * before. 707 */ 708 if (holdtime > lp->cnt_max) 709 lp->cnt_max = holdtime; 710 if (l->lpo_waittime > lp->cnt_wait_max) 711 lp->cnt_wait_max = l->lpo_waittime; 712 lp->cnt_tot += holdtime; 713 lp->cnt_wait += l->lpo_waittime; 714 lp->cnt_contest_locking += l->lpo_contest_locking; 715 lp->cnt_cur += l->lpo_cnt; 716 release: 717 LIST_REMOVE(l, lpo_link); 718 type = &LP_CPU_SELF->lpc_types[spin]; 719 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 720 out: 721 /* 722 * Paired with cpus_fence_seq_cst(). 723 */ 724 atomic_thread_fence_rel(); 725 critical_exit(); 726 } 727 728 static SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, 729 "lock profiling"); 730 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 731 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 732 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW, 733 &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions."); 734 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 735 &lock_prof_rejected, 0, "Number of rejected profiling records"); 736 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, 737 NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics"); 738 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, 739 NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics"); 740 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, 741 NULL, 0, enable_lock_prof, "I", "Enable lock profiling"); 742 743 #endif 744