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 | CTLFLAG_MPSAFE, NULL, 111 "lock debugging"); 112 static SYSCTL_NODE(_debug_lock, OID_AUTO, delay, 113 CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 114 "lock delay"); 115 116 static u_int __read_mostly starvation_limit = 131072; 117 SYSCTL_INT(_debug_lock_delay, OID_AUTO, starvation_limit, CTLFLAG_RW, 118 &starvation_limit, 0, ""); 119 120 static u_int __read_mostly restrict_starvation = 0; 121 SYSCTL_INT(_debug_lock_delay, OID_AUTO, restrict_starvation, CTLFLAG_RW, 122 &restrict_starvation, 0, ""); 123 124 void 125 lock_delay(struct lock_delay_arg *la) 126 { 127 struct lock_delay_config *lc = la->config; 128 u_short i; 129 130 la->delay <<= 1; 131 if (__predict_false(la->delay > lc->max)) 132 la->delay = lc->max; 133 134 for (i = la->delay; i > 0; i--) 135 cpu_spinwait(); 136 137 la->spin_cnt += la->delay; 138 if (__predict_false(la->spin_cnt > starvation_limit)) { 139 SDT_PROBE1(lock, , , starvation, la->delay); 140 if (restrict_starvation) 141 la->delay = lc->base; 142 } 143 } 144 145 static u_int 146 lock_roundup_2(u_int val) 147 { 148 u_int res; 149 150 for (res = 1; res <= val; res <<= 1) 151 continue; 152 153 return (res); 154 } 155 156 void 157 lock_delay_default_init(struct lock_delay_config *lc) 158 { 159 160 lc->base = 1; 161 lc->max = lock_roundup_2(mp_ncpus) * 256; 162 if (lc->max > 32678) 163 lc->max = 32678; 164 } 165 166 struct lock_delay_config __read_frequently locks_delay; 167 u_short __read_frequently locks_delay_retries; 168 u_short __read_frequently locks_delay_loops; 169 170 SYSCTL_U16(_debug_lock, OID_AUTO, delay_base, CTLFLAG_RW, &locks_delay.base, 171 0, ""); 172 SYSCTL_U16(_debug_lock, OID_AUTO, delay_max, CTLFLAG_RW, &locks_delay.max, 173 0, ""); 174 SYSCTL_U16(_debug_lock, OID_AUTO, delay_retries, CTLFLAG_RW, &locks_delay_retries, 175 0, ""); 176 SYSCTL_U16(_debug_lock, OID_AUTO, delay_loops, CTLFLAG_RW, &locks_delay_loops, 177 0, ""); 178 179 static void 180 locks_delay_init(void *arg __unused) 181 { 182 183 lock_delay_default_init(&locks_delay); 184 locks_delay_retries = 10; 185 locks_delay_loops = max(10000, locks_delay.max); 186 } 187 LOCK_DELAY_SYSINIT(locks_delay_init); 188 189 #ifdef DDB 190 DB_SHOW_COMMAND(lock, db_show_lock) 191 { 192 struct lock_object *lock; 193 struct lock_class *class; 194 195 if (!have_addr) 196 return; 197 lock = (struct lock_object *)addr; 198 if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) { 199 db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock)); 200 return; 201 } 202 class = LOCK_CLASS(lock); 203 db_printf(" class: %s\n", class->lc_name); 204 db_printf(" name: %s\n", lock->lo_name); 205 class->lc_ddb_show(lock); 206 } 207 #endif 208 209 #ifdef LOCK_PROFILING 210 211 /* 212 * One object per-thread for each lock the thread owns. Tracks individual 213 * lock instances. 214 */ 215 struct lock_profile_object { 216 LIST_ENTRY(lock_profile_object) lpo_link; 217 struct lock_object *lpo_obj; 218 const char *lpo_file; 219 int lpo_line; 220 uint16_t lpo_ref; 221 uint16_t lpo_cnt; 222 uint64_t lpo_acqtime; 223 uint64_t lpo_waittime; 224 u_int lpo_contest_locking; 225 }; 226 227 /* 228 * One lock_prof for each (file, line, lock object) triple. 229 */ 230 struct lock_prof { 231 SLIST_ENTRY(lock_prof) link; 232 struct lock_class *class; 233 const char *file; 234 const char *name; 235 int line; 236 int ticks; 237 uintmax_t cnt_wait_max; 238 uintmax_t cnt_max; 239 uintmax_t cnt_tot; 240 uintmax_t cnt_wait; 241 uintmax_t cnt_cur; 242 uintmax_t cnt_contest_locking; 243 }; 244 245 SLIST_HEAD(lphead, lock_prof); 246 247 #define LPROF_HASH_SIZE 4096 248 #define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1) 249 #define LPROF_CACHE_SIZE 4096 250 251 /* 252 * Array of objects and profs for each type of object for each cpu. Spinlocks 253 * are handled separately because a thread may be preempted and acquire a 254 * spinlock while in the lock profiling code of a non-spinlock. In this way 255 * we only need a critical section to protect the per-cpu lists. 256 */ 257 struct lock_prof_type { 258 struct lphead lpt_lpalloc; 259 struct lpohead lpt_lpoalloc; 260 struct lphead lpt_hash[LPROF_HASH_SIZE]; 261 struct lock_prof lpt_prof[LPROF_CACHE_SIZE]; 262 struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE]; 263 }; 264 265 struct lock_prof_cpu { 266 struct lock_prof_type lpc_types[2]; /* One for spin one for other. */ 267 }; 268 269 DPCPU_DEFINE_STATIC(struct lock_prof_cpu, lp); 270 #define LP_CPU_SELF (DPCPU_PTR(lp)) 271 #define LP_CPU(cpu) (DPCPU_ID_PTR((cpu), lp)) 272 273 volatile int __read_mostly lock_prof_enable; 274 static volatile int lock_prof_resetting; 275 276 #define LPROF_SBUF_SIZE 256 277 278 static int lock_prof_rejected; 279 static int lock_prof_skipspin; 280 static int lock_prof_skipcount; 281 282 #ifndef USE_CPU_NANOSECONDS 283 uint64_t 284 nanoseconds(void) 285 { 286 struct bintime bt; 287 uint64_t ns; 288 289 binuptime(&bt); 290 /* From bintime2timespec */ 291 ns = bt.sec * (uint64_t)1000000000; 292 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; 293 return (ns); 294 } 295 #endif 296 297 static void 298 lock_prof_init_type(struct lock_prof_type *type) 299 { 300 int i; 301 302 SLIST_INIT(&type->lpt_lpalloc); 303 LIST_INIT(&type->lpt_lpoalloc); 304 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 305 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], 306 link); 307 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], 308 lpo_link); 309 } 310 } 311 312 static void 313 lock_prof_init(void *arg) 314 { 315 int cpu; 316 317 CPU_FOREACH(cpu) { 318 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[0]); 319 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[1]); 320 } 321 } 322 SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); 323 324 static void 325 lock_prof_reset_wait(void) 326 { 327 328 /* 329 * Spin relinquishing our cpu so that quiesce_all_cpus may 330 * complete. 331 */ 332 while (lock_prof_resetting) 333 sched_relinquish(curthread); 334 } 335 336 static void 337 lock_prof_reset(void) 338 { 339 struct lock_prof_cpu *lpc; 340 int enabled, i, cpu; 341 342 /* 343 * We not only race with acquiring and releasing locks but also 344 * thread exit. To be certain that threads exit without valid head 345 * pointers they must see resetting set before enabled is cleared. 346 * Otherwise a lock may not be removed from a per-thread list due 347 * to disabled being set but not wait for reset() to remove it below. 348 */ 349 atomic_store_rel_int(&lock_prof_resetting, 1); 350 enabled = lock_prof_enable; 351 lock_prof_enable = 0; 352 /* 353 * This both publishes lock_prof_enable as disabled and makes sure 354 * everyone else reads it if they are not far enough. We wait for the 355 * rest down below. 356 */ 357 cpus_fence_seq_cst(); 358 quiesce_all_critical(); 359 /* 360 * Some objects may have migrated between CPUs. Clear all links 361 * before we zero the structures. Some items may still be linked 362 * into per-thread lists as well. 363 */ 364 CPU_FOREACH(cpu) { 365 lpc = LP_CPU(cpu); 366 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 367 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 368 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 369 } 370 } 371 CPU_FOREACH(cpu) { 372 lpc = LP_CPU(cpu); 373 bzero(lpc, sizeof(*lpc)); 374 lock_prof_init_type(&lpc->lpc_types[0]); 375 lock_prof_init_type(&lpc->lpc_types[1]); 376 } 377 /* 378 * Paired with the fence from cpus_fence_seq_cst() 379 */ 380 atomic_store_rel_int(&lock_prof_resetting, 0); 381 lock_prof_enable = enabled; 382 } 383 384 static void 385 lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 386 { 387 const char *p; 388 389 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 390 sbuf_printf(sb, 391 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", 392 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, 393 lp->cnt_wait / 1000, lp->cnt_cur, 394 lp->cnt_cur == 0 ? (uintmax_t)0 : 395 lp->cnt_tot / (lp->cnt_cur * 1000), 396 lp->cnt_cur == 0 ? (uintmax_t)0 : 397 lp->cnt_wait / (lp->cnt_cur * 1000), 398 (uintmax_t)0, lp->cnt_contest_locking, 399 p, lp->line, lp->class->lc_name, lp->name); 400 } 401 402 static void 403 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 404 int spin, int t) 405 { 406 struct lock_prof_type *type; 407 struct lock_prof *l; 408 int cpu; 409 410 dst->file = match->file; 411 dst->line = match->line; 412 dst->class = match->class; 413 dst->name = match->name; 414 415 CPU_FOREACH(cpu) { 416 type = &LP_CPU(cpu)->lpc_types[spin]; 417 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 418 if (l->ticks == t) 419 continue; 420 if (l->file != match->file || l->line != match->line || 421 l->name != match->name) 422 continue; 423 l->ticks = t; 424 if (l->cnt_max > dst->cnt_max) 425 dst->cnt_max = l->cnt_max; 426 if (l->cnt_wait_max > dst->cnt_wait_max) 427 dst->cnt_wait_max = l->cnt_wait_max; 428 dst->cnt_tot += l->cnt_tot; 429 dst->cnt_wait += l->cnt_wait; 430 dst->cnt_cur += l->cnt_cur; 431 dst->cnt_contest_locking += l->cnt_contest_locking; 432 } 433 } 434 } 435 436 static void 437 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 438 int t) 439 { 440 struct lock_prof *l; 441 int i; 442 443 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 444 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 445 struct lock_prof lp = {}; 446 447 if (l->ticks == t) 448 continue; 449 lock_prof_sum(l, &lp, i, spin, t); 450 lock_prof_output(&lp, sb); 451 } 452 } 453 } 454 455 static int 456 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 457 { 458 struct sbuf *sb; 459 int error, cpu, t; 460 int enabled; 461 462 error = sysctl_wire_old_buffer(req, 0); 463 if (error != 0) 464 return (error); 465 sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req); 466 sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n", 467 "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); 468 enabled = lock_prof_enable; 469 lock_prof_enable = 0; 470 /* 471 * See the comment in lock_prof_reset 472 */ 473 cpus_fence_seq_cst(); 474 quiesce_all_critical(); 475 t = ticks; 476 CPU_FOREACH(cpu) { 477 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[0], sb, 0, t); 478 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[1], sb, 1, t); 479 } 480 atomic_thread_fence_rel(); 481 lock_prof_enable = enabled; 482 483 error = sbuf_finish(sb); 484 /* Output a trailing NUL. */ 485 if (error == 0) 486 error = SYSCTL_OUT(req, "", 1); 487 sbuf_delete(sb); 488 return (error); 489 } 490 491 static int 492 enable_lock_prof(SYSCTL_HANDLER_ARGS) 493 { 494 int error, v; 495 496 v = lock_prof_enable; 497 error = sysctl_handle_int(oidp, &v, v, req); 498 if (error) 499 return (error); 500 if (req->newptr == NULL) 501 return (error); 502 if (v == lock_prof_enable) 503 return (0); 504 if (v == 1) 505 lock_prof_reset(); 506 lock_prof_enable = !!v; 507 508 return (0); 509 } 510 511 static int 512 reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) 513 { 514 int error, v; 515 516 v = 0; 517 error = sysctl_handle_int(oidp, &v, 0, req); 518 if (error) 519 return (error); 520 if (req->newptr == NULL) 521 return (error); 522 if (v == 0) 523 return (0); 524 lock_prof_reset(); 525 526 return (0); 527 } 528 529 static struct lock_prof * 530 lock_profile_lookup(struct lock_object *lo, int spin, const char *file, 531 int line) 532 { 533 const char *unknown = "(unknown)"; 534 struct lock_prof_type *type; 535 struct lock_prof *lp; 536 struct lphead *head; 537 const char *p; 538 u_int hash; 539 540 p = file; 541 if (p == NULL || *p == '\0') 542 p = unknown; 543 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; 544 hash &= LPROF_HASH_MASK; 545 type = &LP_CPU_SELF->lpc_types[spin]; 546 head = &type->lpt_hash[hash]; 547 SLIST_FOREACH(lp, head, link) { 548 if (lp->line == line && lp->file == p && 549 lp->name == lo->lo_name) 550 return (lp); 551 } 552 lp = SLIST_FIRST(&type->lpt_lpalloc); 553 if (lp == NULL) { 554 lock_prof_rejected++; 555 return (lp); 556 } 557 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); 558 lp->file = p; 559 lp->line = line; 560 lp->class = LOCK_CLASS(lo); 561 lp->name = lo->lo_name; 562 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); 563 return (lp); 564 } 565 566 static struct lock_profile_object * 567 lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, 568 int line) 569 { 570 struct lock_profile_object *l; 571 struct lock_prof_type *type; 572 struct lpohead *head; 573 574 head = &curthread->td_lprof[spin]; 575 LIST_FOREACH(l, head, lpo_link) 576 if (l->lpo_obj == lo && l->lpo_file == file && 577 l->lpo_line == line) 578 return (l); 579 type = &LP_CPU_SELF->lpc_types[spin]; 580 l = LIST_FIRST(&type->lpt_lpoalloc); 581 if (l == NULL) { 582 lock_prof_rejected++; 583 return (NULL); 584 } 585 LIST_REMOVE(l, lpo_link); 586 l->lpo_obj = lo; 587 l->lpo_file = file; 588 l->lpo_line = line; 589 l->lpo_cnt = 0; 590 LIST_INSERT_HEAD(head, l, lpo_link); 591 592 return (l); 593 } 594 595 void 596 lock_profile_obtain_lock_success(struct lock_object *lo, int contested, 597 uint64_t waittime, const char *file, int line) 598 { 599 static int lock_prof_count; 600 struct lock_profile_object *l; 601 int spin; 602 603 if (SCHEDULER_STOPPED()) 604 return; 605 606 /* don't reset the timer when/if recursing */ 607 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 608 return; 609 if (lock_prof_skipcount && 610 (++lock_prof_count % lock_prof_skipcount) != 0) 611 return; 612 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 613 if (spin && lock_prof_skipspin == 1) 614 return; 615 critical_enter(); 616 /* Recheck enabled now that we're in a critical section. */ 617 if (lock_prof_enable == 0) 618 goto out; 619 l = lock_profile_object_lookup(lo, spin, file, line); 620 if (l == NULL) 621 goto out; 622 l->lpo_cnt++; 623 if (++l->lpo_ref > 1) 624 goto out; 625 l->lpo_contest_locking = contested; 626 l->lpo_acqtime = nanoseconds(); 627 if (waittime && (l->lpo_acqtime > waittime)) 628 l->lpo_waittime = l->lpo_acqtime - waittime; 629 else 630 l->lpo_waittime = 0; 631 out: 632 /* 633 * Paired with cpus_fence_seq_cst(). 634 */ 635 atomic_thread_fence_rel(); 636 critical_exit(); 637 } 638 639 void 640 lock_profile_thread_exit(struct thread *td) 641 { 642 #ifdef INVARIANTS 643 struct lock_profile_object *l; 644 645 MPASS(curthread->td_critnest == 0); 646 #endif 647 /* 648 * If lock profiling was disabled we have to wait for reset to 649 * clear our pointers before we can exit safely. 650 */ 651 lock_prof_reset_wait(); 652 #ifdef INVARIANTS 653 LIST_FOREACH(l, &td->td_lprof[0], lpo_link) 654 printf("thread still holds lock acquired at %s:%d\n", 655 l->lpo_file, l->lpo_line); 656 LIST_FOREACH(l, &td->td_lprof[1], lpo_link) 657 printf("thread still holds lock acquired at %s:%d\n", 658 l->lpo_file, l->lpo_line); 659 #endif 660 MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL); 661 MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL); 662 } 663 664 void 665 lock_profile_release_lock(struct lock_object *lo) 666 { 667 struct lock_profile_object *l; 668 struct lock_prof_type *type; 669 struct lock_prof *lp; 670 uint64_t curtime, holdtime; 671 struct lpohead *head; 672 int spin; 673 674 if (SCHEDULER_STOPPED()) 675 return; 676 if (lo->lo_flags & LO_NOPROFILE) 677 return; 678 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; 679 head = &curthread->td_lprof[spin]; 680 if (LIST_FIRST(head) == NULL) 681 return; 682 critical_enter(); 683 /* Recheck enabled now that we're in a critical section. */ 684 if (lock_prof_enable == 0 && lock_prof_resetting == 1) 685 goto out; 686 /* 687 * If lock profiling is not enabled we still want to remove the 688 * lpo from our queue. 689 */ 690 LIST_FOREACH(l, head, lpo_link) 691 if (l->lpo_obj == lo) 692 break; 693 if (l == NULL) 694 goto out; 695 if (--l->lpo_ref > 0) 696 goto out; 697 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 698 if (lp == NULL) 699 goto release; 700 curtime = nanoseconds(); 701 if (curtime < l->lpo_acqtime) 702 goto release; 703 holdtime = curtime - l->lpo_acqtime; 704 705 /* 706 * Record if the lock has been held longer now than ever 707 * before. 708 */ 709 if (holdtime > lp->cnt_max) 710 lp->cnt_max = holdtime; 711 if (l->lpo_waittime > lp->cnt_wait_max) 712 lp->cnt_wait_max = l->lpo_waittime; 713 lp->cnt_tot += holdtime; 714 lp->cnt_wait += l->lpo_waittime; 715 lp->cnt_contest_locking += l->lpo_contest_locking; 716 lp->cnt_cur += l->lpo_cnt; 717 release: 718 LIST_REMOVE(l, lpo_link); 719 type = &LP_CPU_SELF->lpc_types[spin]; 720 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 721 out: 722 /* 723 * Paired with cpus_fence_seq_cst(). 724 */ 725 atomic_thread_fence_rel(); 726 critical_exit(); 727 } 728 729 static SYSCTL_NODE(_debug_lock, OID_AUTO, prof, 730 CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 731 "lock profiling"); 732 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 733 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 734 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW, 735 &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions."); 736 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 737 &lock_prof_rejected, 0, "Number of rejected profiling records"); 738 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, 739 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, 740 dump_lock_prof_stats, "A", 741 "Lock profiling statistics"); 742 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, 743 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0, 744 reset_lock_prof_stats, "I", 745 "Reset lock profiling statistics"); 746 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, 747 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, 748 enable_lock_prof, "I", 749 "Enable lock profiling"); 750 751 #endif 752