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 __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/limits.h> 44 #include <sys/lock.h> 45 #include <sys/lock_profile.h> 46 #include <sys/malloc.h> 47 #include <sys/mutex.h> 48 #include <sys/pcpu.h> 49 #include <sys/proc.h> 50 #include <sys/sbuf.h> 51 #include <sys/sched.h> 52 #include <sys/smp.h> 53 #include <sys/sysctl.h> 54 55 #ifdef DDB 56 #include <ddb/ddb.h> 57 #endif 58 59 #include <machine/cpufunc.h> 60 61 /* 62 * Uncomment to validate that spin argument to acquire/release routines matches 63 * the flag in the lock 64 */ 65 //#define LOCK_PROFILING_DEBUG_SPIN 66 67 CTASSERT(LOCK_CLASS_MAX == 15); 68 69 struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = { 70 &lock_class_mtx_spin, 71 &lock_class_mtx_sleep, 72 &lock_class_sx, 73 &lock_class_rm, 74 &lock_class_rm_sleepable, 75 &lock_class_rw, 76 &lock_class_lockmgr, 77 }; 78 79 void 80 lock_init(struct lock_object *lock, struct lock_class *class, const char *name, 81 const char *type, int flags) 82 { 83 int i; 84 85 /* Check for double-init and zero object. */ 86 KASSERT(flags & LO_NEW || !lock_initialized(lock), 87 ("lock \"%s\" %p already initialized", name, lock)); 88 89 /* Look up lock class to find its index. */ 90 for (i = 0; i < LOCK_CLASS_MAX; i++) 91 if (lock_classes[i] == class) { 92 lock->lo_flags = i << LO_CLASSSHIFT; 93 break; 94 } 95 KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class)); 96 97 /* Initialize the lock object. */ 98 lock->lo_name = name; 99 lock->lo_flags |= flags | LO_INITIALIZED; 100 LOCK_LOG_INIT(lock, 0); 101 WITNESS_INIT(lock, (type != NULL) ? type : name); 102 } 103 104 void 105 lock_destroy(struct lock_object *lock) 106 { 107 108 KASSERT(lock_initialized(lock), ("lock %p is not initialized", lock)); 109 WITNESS_DESTROY(lock); 110 LOCK_LOG_DESTROY(lock, 0); 111 lock->lo_flags &= ~LO_INITIALIZED; 112 } 113 114 static SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 115 "lock debugging"); 116 static SYSCTL_NODE(_debug_lock, OID_AUTO, delay, 117 CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 118 "lock delay"); 119 120 void 121 lock_delay(struct lock_delay_arg *la) 122 { 123 struct lock_delay_config *lc = la->config; 124 u_int i; 125 126 for (i = la->delay; i > 0; i--) 127 cpu_spinwait(); 128 la->spin_cnt += la->delay; 129 130 la->delay <<= 1; 131 if (__predict_false(la->delay > (u_int)lc->max)) 132 la->delay = lc->max; 133 } 134 135 static u_int 136 lock_roundup_2(u_int val) 137 { 138 u_int res; 139 140 for (res = 1; res <= val; res <<= 1) 141 continue; 142 143 return (res); 144 } 145 146 void 147 lock_delay_default_init(struct lock_delay_config *lc) 148 { 149 150 lc->base = 1; 151 lc->max = min(lock_roundup_2(mp_ncpus) * 256, SHRT_MAX); 152 } 153 154 struct lock_delay_config __read_frequently locks_delay; 155 u_short __read_frequently locks_delay_retries; 156 u_short __read_frequently locks_delay_loops; 157 158 SYSCTL_U16(_debug_lock, OID_AUTO, delay_base, CTLFLAG_RW, &locks_delay.base, 159 0, ""); 160 SYSCTL_U16(_debug_lock, OID_AUTO, delay_max, CTLFLAG_RW, &locks_delay.max, 161 0, ""); 162 SYSCTL_U16(_debug_lock, OID_AUTO, delay_retries, CTLFLAG_RW, &locks_delay_retries, 163 0, ""); 164 SYSCTL_U16(_debug_lock, OID_AUTO, delay_loops, CTLFLAG_RW, &locks_delay_loops, 165 0, ""); 166 167 static void 168 locks_delay_init(void *arg __unused) 169 { 170 171 lock_delay_default_init(&locks_delay); 172 locks_delay_retries = 10; 173 locks_delay_loops = max(10000, locks_delay.max); 174 } 175 LOCK_DELAY_SYSINIT(locks_delay_init); 176 177 #ifdef DDB 178 DB_SHOW_COMMAND(lock, db_show_lock) 179 { 180 struct lock_object *lock; 181 struct lock_class *class; 182 183 if (!have_addr) 184 return; 185 lock = (struct lock_object *)addr; 186 if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) { 187 db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock)); 188 return; 189 } 190 class = LOCK_CLASS(lock); 191 db_printf(" class: %s\n", class->lc_name); 192 db_printf(" name: %s\n", lock->lo_name); 193 class->lc_ddb_show(lock); 194 } 195 #endif 196 197 #ifdef LOCK_PROFILING 198 199 /* 200 * One object per-thread for each lock the thread owns. Tracks individual 201 * lock instances. 202 */ 203 struct lock_profile_object { 204 LIST_ENTRY(lock_profile_object) lpo_link; 205 struct lock_object *lpo_obj; 206 const char *lpo_file; 207 int lpo_line; 208 uint16_t lpo_ref; 209 uint16_t lpo_cnt; 210 uint64_t lpo_acqtime; 211 uint64_t lpo_waittime; 212 u_int lpo_contest_locking; 213 }; 214 215 /* 216 * One lock_prof for each (file, line, lock object) triple. 217 */ 218 struct lock_prof { 219 SLIST_ENTRY(lock_prof) link; 220 struct lock_class *class; 221 const char *file; 222 const char *name; 223 int line; 224 int ticks; 225 uintmax_t cnt_wait_max; 226 uintmax_t cnt_max; 227 uintmax_t cnt_tot; 228 uintmax_t cnt_wait; 229 uintmax_t cnt_cur; 230 uintmax_t cnt_contest_locking; 231 }; 232 233 SLIST_HEAD(lphead, lock_prof); 234 235 #define LPROF_HASH_SIZE 4096 236 #define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1) 237 #define LPROF_CACHE_SIZE 4096 238 239 /* 240 * Array of objects and profs for each type of object for each cpu. Spinlocks 241 * are handled separately because a thread may be preempted and acquire a 242 * spinlock while in the lock profiling code of a non-spinlock. In this way 243 * we only need a critical section to protect the per-cpu lists. 244 */ 245 struct lock_prof_type { 246 struct lphead lpt_lpalloc; 247 struct lpohead lpt_lpoalloc; 248 struct lphead lpt_hash[LPROF_HASH_SIZE]; 249 struct lock_prof lpt_prof[LPROF_CACHE_SIZE]; 250 struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE]; 251 }; 252 253 struct lock_prof_cpu { 254 struct lock_prof_type lpc_types[2]; /* One for spin one for other. */ 255 }; 256 257 DPCPU_DEFINE_STATIC(struct lock_prof_cpu, lp); 258 #define LP_CPU_SELF (DPCPU_PTR(lp)) 259 #define LP_CPU(cpu) (DPCPU_ID_PTR((cpu), lp)) 260 261 volatile int __read_mostly lock_prof_enable; 262 int __read_mostly lock_contested_only; 263 static volatile int lock_prof_resetting; 264 265 #define LPROF_SBUF_SIZE 256 266 267 static int lock_prof_rejected; 268 static int lock_prof_skipspin; 269 270 #ifndef USE_CPU_NANOSECONDS 271 uint64_t 272 nanoseconds(void) 273 { 274 struct bintime bt; 275 uint64_t ns; 276 277 binuptime(&bt); 278 /* From bintime2timespec */ 279 ns = bt.sec * (uint64_t)1000000000; 280 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; 281 return (ns); 282 } 283 #endif 284 285 static void 286 lock_prof_init_type(struct lock_prof_type *type) 287 { 288 int i; 289 290 SLIST_INIT(&type->lpt_lpalloc); 291 LIST_INIT(&type->lpt_lpoalloc); 292 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 293 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], 294 link); 295 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], 296 lpo_link); 297 } 298 } 299 300 static void 301 lock_prof_init(void *arg) 302 { 303 int cpu; 304 305 CPU_FOREACH(cpu) { 306 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[0]); 307 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[1]); 308 } 309 } 310 SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); 311 312 static void 313 lock_prof_reset_wait(void) 314 { 315 316 /* 317 * Spin relinquishing our cpu so that quiesce_all_cpus may 318 * complete. 319 */ 320 while (lock_prof_resetting) 321 sched_relinquish(curthread); 322 } 323 324 static void 325 lock_prof_reset(void) 326 { 327 struct lock_prof_cpu *lpc; 328 int enabled, i, cpu; 329 330 /* 331 * We not only race with acquiring and releasing locks but also 332 * thread exit. To be certain that threads exit without valid head 333 * pointers they must see resetting set before enabled is cleared. 334 * Otherwise a lock may not be removed from a per-thread list due 335 * to disabled being set but not wait for reset() to remove it below. 336 */ 337 atomic_store_rel_int(&lock_prof_resetting, 1); 338 enabled = lock_prof_enable; 339 lock_prof_enable = 0; 340 /* 341 * This both publishes lock_prof_enable as disabled and makes sure 342 * everyone else reads it if they are not far enough. We wait for the 343 * rest down below. 344 */ 345 cpus_fence_seq_cst(); 346 quiesce_all_critical(); 347 /* 348 * Some objects may have migrated between CPUs. Clear all links 349 * before we zero the structures. Some items may still be linked 350 * into per-thread lists as well. 351 */ 352 CPU_FOREACH(cpu) { 353 lpc = LP_CPU(cpu); 354 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 355 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 356 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 357 } 358 } 359 CPU_FOREACH(cpu) { 360 lpc = LP_CPU(cpu); 361 bzero(lpc, sizeof(*lpc)); 362 lock_prof_init_type(&lpc->lpc_types[0]); 363 lock_prof_init_type(&lpc->lpc_types[1]); 364 } 365 /* 366 * Paired with the fence from cpus_fence_seq_cst() 367 */ 368 atomic_store_rel_int(&lock_prof_resetting, 0); 369 lock_prof_enable = enabled; 370 } 371 372 static void 373 lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 374 { 375 const char *p; 376 377 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 378 sbuf_printf(sb, 379 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", 380 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, 381 lp->cnt_wait / 1000, lp->cnt_cur, 382 lp->cnt_cur == 0 ? (uintmax_t)0 : 383 lp->cnt_tot / (lp->cnt_cur * 1000), 384 lp->cnt_cur == 0 ? (uintmax_t)0 : 385 lp->cnt_wait / (lp->cnt_cur * 1000), 386 (uintmax_t)0, lp->cnt_contest_locking, 387 p, lp->line, lp->class->lc_name, lp->name); 388 } 389 390 static void 391 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 392 int spin, int t) 393 { 394 struct lock_prof_type *type; 395 struct lock_prof *l; 396 int cpu; 397 398 dst->file = match->file; 399 dst->line = match->line; 400 dst->class = match->class; 401 dst->name = match->name; 402 403 CPU_FOREACH(cpu) { 404 type = &LP_CPU(cpu)->lpc_types[spin]; 405 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 406 if (l->ticks == t) 407 continue; 408 if (l->file != match->file || l->line != match->line || 409 l->name != match->name) 410 continue; 411 l->ticks = t; 412 if (l->cnt_max > dst->cnt_max) 413 dst->cnt_max = l->cnt_max; 414 if (l->cnt_wait_max > dst->cnt_wait_max) 415 dst->cnt_wait_max = l->cnt_wait_max; 416 dst->cnt_tot += l->cnt_tot; 417 dst->cnt_wait += l->cnt_wait; 418 dst->cnt_cur += l->cnt_cur; 419 dst->cnt_contest_locking += l->cnt_contest_locking; 420 } 421 } 422 } 423 424 static void 425 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 426 int t) 427 { 428 struct lock_prof *l; 429 int i; 430 431 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 432 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 433 struct lock_prof lp = {}; 434 435 if (l->ticks == t) 436 continue; 437 lock_prof_sum(l, &lp, i, spin, t); 438 lock_prof_output(&lp, sb); 439 } 440 } 441 } 442 443 static int 444 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 445 { 446 struct sbuf *sb; 447 int error, cpu, t; 448 int enabled; 449 450 error = sysctl_wire_old_buffer(req, 0); 451 if (error != 0) 452 return (error); 453 sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req); 454 sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n", 455 "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); 456 enabled = lock_prof_enable; 457 lock_prof_enable = 0; 458 /* 459 * See the comment in lock_prof_reset 460 */ 461 cpus_fence_seq_cst(); 462 quiesce_all_critical(); 463 t = ticks; 464 CPU_FOREACH(cpu) { 465 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[0], sb, 0, t); 466 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[1], sb, 1, t); 467 } 468 atomic_thread_fence_rel(); 469 lock_prof_enable = enabled; 470 471 error = sbuf_finish(sb); 472 /* Output a trailing NUL. */ 473 if (error == 0) 474 error = SYSCTL_OUT(req, "", 1); 475 sbuf_delete(sb); 476 return (error); 477 } 478 479 static int 480 enable_lock_prof(SYSCTL_HANDLER_ARGS) 481 { 482 int error, v; 483 484 v = lock_prof_enable; 485 error = sysctl_handle_int(oidp, &v, v, req); 486 if (error) 487 return (error); 488 if (req->newptr == NULL) 489 return (error); 490 if (v == lock_prof_enable) 491 return (0); 492 if (v == 1) 493 lock_prof_reset(); 494 lock_prof_enable = !!v; 495 496 return (0); 497 } 498 499 static int 500 reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) 501 { 502 int error, v; 503 504 v = 0; 505 error = sysctl_handle_int(oidp, &v, 0, req); 506 if (error) 507 return (error); 508 if (req->newptr == NULL) 509 return (error); 510 if (v == 0) 511 return (0); 512 lock_prof_reset(); 513 514 return (0); 515 } 516 517 static struct lock_prof * 518 lock_profile_lookup(struct lock_object *lo, int spin, const char *file, 519 int line) 520 { 521 const char *unknown = "(unknown)"; 522 struct lock_prof_type *type; 523 struct lock_prof *lp; 524 struct lphead *head; 525 const char *p; 526 u_int hash; 527 528 p = file; 529 if (p == NULL || *p == '\0') 530 p = unknown; 531 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; 532 hash &= LPROF_HASH_MASK; 533 type = &LP_CPU_SELF->lpc_types[spin]; 534 head = &type->lpt_hash[hash]; 535 SLIST_FOREACH(lp, head, link) { 536 if (lp->line == line && lp->file == p && 537 lp->name == lo->lo_name) 538 return (lp); 539 } 540 lp = SLIST_FIRST(&type->lpt_lpalloc); 541 if (lp == NULL) { 542 lock_prof_rejected++; 543 return (lp); 544 } 545 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); 546 lp->file = p; 547 lp->line = line; 548 lp->class = LOCK_CLASS(lo); 549 lp->name = lo->lo_name; 550 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); 551 return (lp); 552 } 553 554 static struct lock_profile_object * 555 lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, 556 int line) 557 { 558 struct lock_profile_object *l; 559 struct lock_prof_type *type; 560 struct lpohead *head; 561 562 head = &curthread->td_lprof[spin]; 563 LIST_FOREACH(l, head, lpo_link) 564 if (l->lpo_obj == lo && l->lpo_file == file && 565 l->lpo_line == line) 566 return (l); 567 type = &LP_CPU_SELF->lpc_types[spin]; 568 l = LIST_FIRST(&type->lpt_lpoalloc); 569 if (l == NULL) { 570 lock_prof_rejected++; 571 return (NULL); 572 } 573 LIST_REMOVE(l, lpo_link); 574 l->lpo_obj = lo; 575 l->lpo_file = file; 576 l->lpo_line = line; 577 l->lpo_cnt = 0; 578 LIST_INSERT_HEAD(head, l, lpo_link); 579 580 return (l); 581 } 582 583 void 584 lock_profile_obtain_lock_success(struct lock_object *lo, bool spin, 585 int contested, uint64_t waittime, const char *file, int line) 586 { 587 struct lock_profile_object *l; 588 589 #ifdef LOCK_PROFILING_DEBUG_SPIN 590 bool is_spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK); 591 if ((spin && !is_spin) || (!spin && is_spin)) 592 printf("%s: lock %s spin mismatch (arg %d, flag %d)\n", __func__, 593 lo->lo_name, spin, is_spin); 594 #endif 595 596 /* don't reset the timer when/if recursing */ 597 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 598 return; 599 if (lock_contested_only && !contested) 600 return; 601 if (spin && lock_prof_skipspin == 1) 602 return; 603 604 if (SCHEDULER_STOPPED()) 605 return; 606 607 critical_enter(); 608 /* Recheck enabled now that we're in a critical section. */ 609 if (lock_prof_enable == 0) 610 goto out; 611 l = lock_profile_object_lookup(lo, spin, file, line); 612 if (l == NULL) 613 goto out; 614 l->lpo_cnt++; 615 if (++l->lpo_ref > 1) 616 goto out; 617 l->lpo_contest_locking = contested; 618 l->lpo_acqtime = nanoseconds(); 619 if (waittime && (l->lpo_acqtime > waittime)) 620 l->lpo_waittime = l->lpo_acqtime - waittime; 621 else 622 l->lpo_waittime = 0; 623 out: 624 /* 625 * Paired with cpus_fence_seq_cst(). 626 */ 627 atomic_thread_fence_rel(); 628 critical_exit(); 629 } 630 631 void 632 lock_profile_thread_exit(struct thread *td) 633 { 634 #ifdef INVARIANTS 635 struct lock_profile_object *l; 636 637 MPASS(curthread->td_critnest == 0); 638 #endif 639 /* 640 * If lock profiling was disabled we have to wait for reset to 641 * clear our pointers before we can exit safely. 642 */ 643 lock_prof_reset_wait(); 644 #ifdef INVARIANTS 645 LIST_FOREACH(l, &td->td_lprof[0], lpo_link) 646 printf("thread still holds lock acquired at %s:%d\n", 647 l->lpo_file, l->lpo_line); 648 LIST_FOREACH(l, &td->td_lprof[1], lpo_link) 649 printf("thread still holds lock acquired at %s:%d\n", 650 l->lpo_file, l->lpo_line); 651 #endif 652 MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL); 653 MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL); 654 } 655 656 void 657 lock_profile_release_lock(struct lock_object *lo, bool spin) 658 { 659 struct lock_profile_object *l; 660 struct lock_prof_type *type; 661 struct lock_prof *lp; 662 uint64_t curtime, holdtime; 663 struct lpohead *head; 664 665 #ifdef LOCK_PROFILING_DEBUG_SPIN 666 bool is_spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK); 667 if ((spin && !is_spin) || (!spin && is_spin)) 668 printf("%s: lock %s spin mismatch (arg %d, flag %d)\n", __func__, 669 lo->lo_name, spin, is_spin); 670 #endif 671 672 if (lo->lo_flags & LO_NOPROFILE) 673 return; 674 head = &curthread->td_lprof[spin]; 675 if (LIST_FIRST(head) == NULL) 676 return; 677 if (SCHEDULER_STOPPED()) 678 return; 679 critical_enter(); 680 /* Recheck enabled now that we're in a critical section. */ 681 if (lock_prof_enable == 0 && lock_prof_resetting == 1) 682 goto out; 683 /* 684 * If lock profiling is not enabled we still want to remove the 685 * lpo from our queue. 686 */ 687 LIST_FOREACH(l, head, lpo_link) 688 if (l->lpo_obj == lo) 689 break; 690 if (l == NULL) 691 goto out; 692 if (--l->lpo_ref > 0) 693 goto out; 694 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 695 if (lp == NULL) 696 goto release; 697 curtime = nanoseconds(); 698 if (curtime < l->lpo_acqtime) 699 goto release; 700 holdtime = curtime - l->lpo_acqtime; 701 702 /* 703 * Record if the lock has been held longer now than ever 704 * before. 705 */ 706 if (holdtime > lp->cnt_max) 707 lp->cnt_max = holdtime; 708 if (l->lpo_waittime > lp->cnt_wait_max) 709 lp->cnt_wait_max = l->lpo_waittime; 710 lp->cnt_tot += holdtime; 711 lp->cnt_wait += l->lpo_waittime; 712 lp->cnt_contest_locking += l->lpo_contest_locking; 713 lp->cnt_cur += l->lpo_cnt; 714 release: 715 LIST_REMOVE(l, lpo_link); 716 type = &LP_CPU_SELF->lpc_types[spin]; 717 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 718 out: 719 /* 720 * Paired with cpus_fence_seq_cst(). 721 */ 722 atomic_thread_fence_rel(); 723 critical_exit(); 724 } 725 726 static SYSCTL_NODE(_debug_lock, OID_AUTO, prof, 727 CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 728 "lock profiling"); 729 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 730 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 731 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 732 &lock_prof_rejected, 0, "Number of rejected profiling records"); 733 SYSCTL_INT(_debug_lock_prof, OID_AUTO, contested_only, CTLFLAG_RW, 734 &lock_contested_only, 0, "Only profile contested acquires"); 735 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, 736 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, 737 dump_lock_prof_stats, "A", 738 "Lock profiling statistics"); 739 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, 740 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0, 741 reset_lock_prof_stats, "I", 742 "Reset lock profiling statistics"); 743 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, 744 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, 745 enable_lock_prof, "I", 746 "Enable lock profiling"); 747 748 #endif 749