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/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 SDT_PROVIDER_DEFINE(lock); 68 SDT_PROBE_DEFINE1(lock, , , starvation, "u_int"); 69 70 CTASSERT(LOCK_CLASS_MAX == 15); 71 72 struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = { 73 &lock_class_mtx_spin, 74 &lock_class_mtx_sleep, 75 &lock_class_sx, 76 &lock_class_rm, 77 &lock_class_rm_sleepable, 78 &lock_class_rw, 79 &lock_class_lockmgr, 80 }; 81 82 void 83 lock_init(struct lock_object *lock, struct lock_class *class, const char *name, 84 const char *type, int flags) 85 { 86 int i; 87 88 /* Check for double-init and zero object. */ 89 KASSERT(flags & LO_NEW || !lock_initialized(lock), 90 ("lock \"%s\" %p already initialized", name, lock)); 91 92 /* Look up lock class to find its index. */ 93 for (i = 0; i < LOCK_CLASS_MAX; i++) 94 if (lock_classes[i] == class) { 95 lock->lo_flags = i << LO_CLASSSHIFT; 96 break; 97 } 98 KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class)); 99 100 /* Initialize the lock object. */ 101 lock->lo_name = name; 102 lock->lo_flags |= flags | LO_INITIALIZED; 103 LOCK_LOG_INIT(lock, 0); 104 WITNESS_INIT(lock, (type != NULL) ? type : name); 105 } 106 107 void 108 lock_destroy(struct lock_object *lock) 109 { 110 111 KASSERT(lock_initialized(lock), ("lock %p is not initialized", lock)); 112 WITNESS_DESTROY(lock); 113 LOCK_LOG_DESTROY(lock, 0); 114 lock->lo_flags &= ~LO_INITIALIZED; 115 } 116 117 static SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 118 "lock debugging"); 119 static SYSCTL_NODE(_debug_lock, OID_AUTO, delay, 120 CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 121 "lock delay"); 122 123 static u_int __read_mostly starvation_limit = 131072; 124 SYSCTL_INT(_debug_lock_delay, OID_AUTO, starvation_limit, CTLFLAG_RW, 125 &starvation_limit, 0, ""); 126 127 static u_int __read_mostly restrict_starvation = 0; 128 SYSCTL_INT(_debug_lock_delay, OID_AUTO, restrict_starvation, CTLFLAG_RW, 129 &restrict_starvation, 0, ""); 130 131 void 132 lock_delay(struct lock_delay_arg *la) 133 { 134 struct lock_delay_config *lc = la->config; 135 u_short i; 136 137 for (i = la->delay; i > 0; i--) 138 cpu_spinwait(); 139 la->spin_cnt += la->delay; 140 141 la->delay <<= 1; 142 if (__predict_false(la->delay > lc->max)) 143 la->delay = lc->max; 144 145 if (__predict_false(la->spin_cnt > starvation_limit)) { 146 SDT_PROBE1(lock, , , starvation, la->delay); 147 if (restrict_starvation) 148 la->delay = lc->base; 149 } 150 } 151 152 static u_int 153 lock_roundup_2(u_int val) 154 { 155 u_int res; 156 157 for (res = 1; res <= val; res <<= 1) 158 continue; 159 160 return (res); 161 } 162 163 void 164 lock_delay_default_init(struct lock_delay_config *lc) 165 { 166 167 lc->base = 1; 168 lc->max = lock_roundup_2(mp_ncpus) * 256; 169 if (lc->max > 32678) 170 lc->max = 32678; 171 } 172 173 struct lock_delay_config __read_frequently locks_delay; 174 u_short __read_frequently locks_delay_retries; 175 u_short __read_frequently locks_delay_loops; 176 177 SYSCTL_U16(_debug_lock, OID_AUTO, delay_base, CTLFLAG_RW, &locks_delay.base, 178 0, ""); 179 SYSCTL_U16(_debug_lock, OID_AUTO, delay_max, CTLFLAG_RW, &locks_delay.max, 180 0, ""); 181 SYSCTL_U16(_debug_lock, OID_AUTO, delay_retries, CTLFLAG_RW, &locks_delay_retries, 182 0, ""); 183 SYSCTL_U16(_debug_lock, OID_AUTO, delay_loops, CTLFLAG_RW, &locks_delay_loops, 184 0, ""); 185 186 static void 187 locks_delay_init(void *arg __unused) 188 { 189 190 lock_delay_default_init(&locks_delay); 191 locks_delay_retries = 10; 192 locks_delay_loops = max(10000, locks_delay.max); 193 } 194 LOCK_DELAY_SYSINIT(locks_delay_init); 195 196 #ifdef DDB 197 DB_SHOW_COMMAND(lock, db_show_lock) 198 { 199 struct lock_object *lock; 200 struct lock_class *class; 201 202 if (!have_addr) 203 return; 204 lock = (struct lock_object *)addr; 205 if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) { 206 db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock)); 207 return; 208 } 209 class = LOCK_CLASS(lock); 210 db_printf(" class: %s\n", class->lc_name); 211 db_printf(" name: %s\n", lock->lo_name); 212 class->lc_ddb_show(lock); 213 } 214 #endif 215 216 #ifdef LOCK_PROFILING 217 218 /* 219 * One object per-thread for each lock the thread owns. Tracks individual 220 * lock instances. 221 */ 222 struct lock_profile_object { 223 LIST_ENTRY(lock_profile_object) lpo_link; 224 struct lock_object *lpo_obj; 225 const char *lpo_file; 226 int lpo_line; 227 uint16_t lpo_ref; 228 uint16_t lpo_cnt; 229 uint64_t lpo_acqtime; 230 uint64_t lpo_waittime; 231 u_int lpo_contest_locking; 232 }; 233 234 /* 235 * One lock_prof for each (file, line, lock object) triple. 236 */ 237 struct lock_prof { 238 SLIST_ENTRY(lock_prof) link; 239 struct lock_class *class; 240 const char *file; 241 const char *name; 242 int line; 243 int ticks; 244 uintmax_t cnt_wait_max; 245 uintmax_t cnt_max; 246 uintmax_t cnt_tot; 247 uintmax_t cnt_wait; 248 uintmax_t cnt_cur; 249 uintmax_t cnt_contest_locking; 250 }; 251 252 SLIST_HEAD(lphead, lock_prof); 253 254 #define LPROF_HASH_SIZE 4096 255 #define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1) 256 #define LPROF_CACHE_SIZE 4096 257 258 /* 259 * Array of objects and profs for each type of object for each cpu. Spinlocks 260 * are handled separately because a thread may be preempted and acquire a 261 * spinlock while in the lock profiling code of a non-spinlock. In this way 262 * we only need a critical section to protect the per-cpu lists. 263 */ 264 struct lock_prof_type { 265 struct lphead lpt_lpalloc; 266 struct lpohead lpt_lpoalloc; 267 struct lphead lpt_hash[LPROF_HASH_SIZE]; 268 struct lock_prof lpt_prof[LPROF_CACHE_SIZE]; 269 struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE]; 270 }; 271 272 struct lock_prof_cpu { 273 struct lock_prof_type lpc_types[2]; /* One for spin one for other. */ 274 }; 275 276 DPCPU_DEFINE_STATIC(struct lock_prof_cpu, lp); 277 #define LP_CPU_SELF (DPCPU_PTR(lp)) 278 #define LP_CPU(cpu) (DPCPU_ID_PTR((cpu), lp)) 279 280 volatile int __read_mostly lock_prof_enable; 281 int __read_mostly lock_contested_only; 282 static volatile int lock_prof_resetting; 283 284 #define LPROF_SBUF_SIZE 256 285 286 static int lock_prof_rejected; 287 static int lock_prof_skipspin; 288 289 #ifndef USE_CPU_NANOSECONDS 290 uint64_t 291 nanoseconds(void) 292 { 293 struct bintime bt; 294 uint64_t ns; 295 296 binuptime(&bt); 297 /* From bintime2timespec */ 298 ns = bt.sec * (uint64_t)1000000000; 299 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32; 300 return (ns); 301 } 302 #endif 303 304 static void 305 lock_prof_init_type(struct lock_prof_type *type) 306 { 307 int i; 308 309 SLIST_INIT(&type->lpt_lpalloc); 310 LIST_INIT(&type->lpt_lpoalloc); 311 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 312 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i], 313 link); 314 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i], 315 lpo_link); 316 } 317 } 318 319 static void 320 lock_prof_init(void *arg) 321 { 322 int cpu; 323 324 CPU_FOREACH(cpu) { 325 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[0]); 326 lock_prof_init_type(&LP_CPU(cpu)->lpc_types[1]); 327 } 328 } 329 SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL); 330 331 static void 332 lock_prof_reset_wait(void) 333 { 334 335 /* 336 * Spin relinquishing our cpu so that quiesce_all_cpus may 337 * complete. 338 */ 339 while (lock_prof_resetting) 340 sched_relinquish(curthread); 341 } 342 343 static void 344 lock_prof_reset(void) 345 { 346 struct lock_prof_cpu *lpc; 347 int enabled, i, cpu; 348 349 /* 350 * We not only race with acquiring and releasing locks but also 351 * thread exit. To be certain that threads exit without valid head 352 * pointers they must see resetting set before enabled is cleared. 353 * Otherwise a lock may not be removed from a per-thread list due 354 * to disabled being set but not wait for reset() to remove it below. 355 */ 356 atomic_store_rel_int(&lock_prof_resetting, 1); 357 enabled = lock_prof_enable; 358 lock_prof_enable = 0; 359 /* 360 * This both publishes lock_prof_enable as disabled and makes sure 361 * everyone else reads it if they are not far enough. We wait for the 362 * rest down below. 363 */ 364 cpus_fence_seq_cst(); 365 quiesce_all_critical(); 366 /* 367 * Some objects may have migrated between CPUs. Clear all links 368 * before we zero the structures. Some items may still be linked 369 * into per-thread lists as well. 370 */ 371 CPU_FOREACH(cpu) { 372 lpc = LP_CPU(cpu); 373 for (i = 0; i < LPROF_CACHE_SIZE; i++) { 374 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link); 375 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link); 376 } 377 } 378 CPU_FOREACH(cpu) { 379 lpc = LP_CPU(cpu); 380 bzero(lpc, sizeof(*lpc)); 381 lock_prof_init_type(&lpc->lpc_types[0]); 382 lock_prof_init_type(&lpc->lpc_types[1]); 383 } 384 /* 385 * Paired with the fence from cpus_fence_seq_cst() 386 */ 387 atomic_store_rel_int(&lock_prof_resetting, 0); 388 lock_prof_enable = enabled; 389 } 390 391 static void 392 lock_prof_output(struct lock_prof *lp, struct sbuf *sb) 393 { 394 const char *p; 395 396 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3); 397 sbuf_printf(sb, 398 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n", 399 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000, 400 lp->cnt_wait / 1000, lp->cnt_cur, 401 lp->cnt_cur == 0 ? (uintmax_t)0 : 402 lp->cnt_tot / (lp->cnt_cur * 1000), 403 lp->cnt_cur == 0 ? (uintmax_t)0 : 404 lp->cnt_wait / (lp->cnt_cur * 1000), 405 (uintmax_t)0, lp->cnt_contest_locking, 406 p, lp->line, lp->class->lc_name, lp->name); 407 } 408 409 static void 410 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash, 411 int spin, int t) 412 { 413 struct lock_prof_type *type; 414 struct lock_prof *l; 415 int cpu; 416 417 dst->file = match->file; 418 dst->line = match->line; 419 dst->class = match->class; 420 dst->name = match->name; 421 422 CPU_FOREACH(cpu) { 423 type = &LP_CPU(cpu)->lpc_types[spin]; 424 SLIST_FOREACH(l, &type->lpt_hash[hash], link) { 425 if (l->ticks == t) 426 continue; 427 if (l->file != match->file || l->line != match->line || 428 l->name != match->name) 429 continue; 430 l->ticks = t; 431 if (l->cnt_max > dst->cnt_max) 432 dst->cnt_max = l->cnt_max; 433 if (l->cnt_wait_max > dst->cnt_wait_max) 434 dst->cnt_wait_max = l->cnt_wait_max; 435 dst->cnt_tot += l->cnt_tot; 436 dst->cnt_wait += l->cnt_wait; 437 dst->cnt_cur += l->cnt_cur; 438 dst->cnt_contest_locking += l->cnt_contest_locking; 439 } 440 } 441 } 442 443 static void 444 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin, 445 int t) 446 { 447 struct lock_prof *l; 448 int i; 449 450 for (i = 0; i < LPROF_HASH_SIZE; ++i) { 451 SLIST_FOREACH(l, &type->lpt_hash[i], link) { 452 struct lock_prof lp = {}; 453 454 if (l->ticks == t) 455 continue; 456 lock_prof_sum(l, &lp, i, spin, t); 457 lock_prof_output(&lp, sb); 458 } 459 } 460 } 461 462 static int 463 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS) 464 { 465 struct sbuf *sb; 466 int error, cpu, t; 467 int enabled; 468 469 error = sysctl_wire_old_buffer(req, 0); 470 if (error != 0) 471 return (error); 472 sb = sbuf_new_for_sysctl(NULL, NULL, LPROF_SBUF_SIZE, req); 473 sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n", 474 "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name"); 475 enabled = lock_prof_enable; 476 lock_prof_enable = 0; 477 /* 478 * See the comment in lock_prof_reset 479 */ 480 cpus_fence_seq_cst(); 481 quiesce_all_critical(); 482 t = ticks; 483 CPU_FOREACH(cpu) { 484 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[0], sb, 0, t); 485 lock_prof_type_stats(&LP_CPU(cpu)->lpc_types[1], sb, 1, t); 486 } 487 atomic_thread_fence_rel(); 488 lock_prof_enable = enabled; 489 490 error = sbuf_finish(sb); 491 /* Output a trailing NUL. */ 492 if (error == 0) 493 error = SYSCTL_OUT(req, "", 1); 494 sbuf_delete(sb); 495 return (error); 496 } 497 498 static int 499 enable_lock_prof(SYSCTL_HANDLER_ARGS) 500 { 501 int error, v; 502 503 v = lock_prof_enable; 504 error = sysctl_handle_int(oidp, &v, v, req); 505 if (error) 506 return (error); 507 if (req->newptr == NULL) 508 return (error); 509 if (v == lock_prof_enable) 510 return (0); 511 if (v == 1) 512 lock_prof_reset(); 513 lock_prof_enable = !!v; 514 515 return (0); 516 } 517 518 static int 519 reset_lock_prof_stats(SYSCTL_HANDLER_ARGS) 520 { 521 int error, v; 522 523 v = 0; 524 error = sysctl_handle_int(oidp, &v, 0, req); 525 if (error) 526 return (error); 527 if (req->newptr == NULL) 528 return (error); 529 if (v == 0) 530 return (0); 531 lock_prof_reset(); 532 533 return (0); 534 } 535 536 static struct lock_prof * 537 lock_profile_lookup(struct lock_object *lo, int spin, const char *file, 538 int line) 539 { 540 const char *unknown = "(unknown)"; 541 struct lock_prof_type *type; 542 struct lock_prof *lp; 543 struct lphead *head; 544 const char *p; 545 u_int hash; 546 547 p = file; 548 if (p == NULL || *p == '\0') 549 p = unknown; 550 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line; 551 hash &= LPROF_HASH_MASK; 552 type = &LP_CPU_SELF->lpc_types[spin]; 553 head = &type->lpt_hash[hash]; 554 SLIST_FOREACH(lp, head, link) { 555 if (lp->line == line && lp->file == p && 556 lp->name == lo->lo_name) 557 return (lp); 558 } 559 lp = SLIST_FIRST(&type->lpt_lpalloc); 560 if (lp == NULL) { 561 lock_prof_rejected++; 562 return (lp); 563 } 564 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link); 565 lp->file = p; 566 lp->line = line; 567 lp->class = LOCK_CLASS(lo); 568 lp->name = lo->lo_name; 569 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link); 570 return (lp); 571 } 572 573 static struct lock_profile_object * 574 lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file, 575 int line) 576 { 577 struct lock_profile_object *l; 578 struct lock_prof_type *type; 579 struct lpohead *head; 580 581 head = &curthread->td_lprof[spin]; 582 LIST_FOREACH(l, head, lpo_link) 583 if (l->lpo_obj == lo && l->lpo_file == file && 584 l->lpo_line == line) 585 return (l); 586 type = &LP_CPU_SELF->lpc_types[spin]; 587 l = LIST_FIRST(&type->lpt_lpoalloc); 588 if (l == NULL) { 589 lock_prof_rejected++; 590 return (NULL); 591 } 592 LIST_REMOVE(l, lpo_link); 593 l->lpo_obj = lo; 594 l->lpo_file = file; 595 l->lpo_line = line; 596 l->lpo_cnt = 0; 597 LIST_INSERT_HEAD(head, l, lpo_link); 598 599 return (l); 600 } 601 602 void 603 lock_profile_obtain_lock_success(struct lock_object *lo, bool spin, 604 int contested, uint64_t waittime, const char *file, int line) 605 { 606 struct lock_profile_object *l; 607 608 #ifdef LOCK_PROFILING_DEBUG_SPIN 609 bool is_spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK); 610 if ((spin && !is_spin) || (!spin && is_spin)) 611 printf("%s: lock %s spin mismatch (arg %d, flag %d)\n", __func__, 612 lo->lo_name, spin, is_spin); 613 #endif 614 615 /* don't reset the timer when/if recursing */ 616 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) 617 return; 618 if (lock_contested_only && !contested) 619 return; 620 if (spin && lock_prof_skipspin == 1) 621 return; 622 623 if (SCHEDULER_STOPPED()) 624 return; 625 626 critical_enter(); 627 /* Recheck enabled now that we're in a critical section. */ 628 if (lock_prof_enable == 0) 629 goto out; 630 l = lock_profile_object_lookup(lo, spin, file, line); 631 if (l == NULL) 632 goto out; 633 l->lpo_cnt++; 634 if (++l->lpo_ref > 1) 635 goto out; 636 l->lpo_contest_locking = contested; 637 l->lpo_acqtime = nanoseconds(); 638 if (waittime && (l->lpo_acqtime > waittime)) 639 l->lpo_waittime = l->lpo_acqtime - waittime; 640 else 641 l->lpo_waittime = 0; 642 out: 643 /* 644 * Paired with cpus_fence_seq_cst(). 645 */ 646 atomic_thread_fence_rel(); 647 critical_exit(); 648 } 649 650 void 651 lock_profile_thread_exit(struct thread *td) 652 { 653 #ifdef INVARIANTS 654 struct lock_profile_object *l; 655 656 MPASS(curthread->td_critnest == 0); 657 #endif 658 /* 659 * If lock profiling was disabled we have to wait for reset to 660 * clear our pointers before we can exit safely. 661 */ 662 lock_prof_reset_wait(); 663 #ifdef INVARIANTS 664 LIST_FOREACH(l, &td->td_lprof[0], lpo_link) 665 printf("thread still holds lock acquired at %s:%d\n", 666 l->lpo_file, l->lpo_line); 667 LIST_FOREACH(l, &td->td_lprof[1], lpo_link) 668 printf("thread still holds lock acquired at %s:%d\n", 669 l->lpo_file, l->lpo_line); 670 #endif 671 MPASS(LIST_FIRST(&td->td_lprof[0]) == NULL); 672 MPASS(LIST_FIRST(&td->td_lprof[1]) == NULL); 673 } 674 675 void 676 lock_profile_release_lock(struct lock_object *lo, bool spin) 677 { 678 struct lock_profile_object *l; 679 struct lock_prof_type *type; 680 struct lock_prof *lp; 681 uint64_t curtime, holdtime; 682 struct lpohead *head; 683 684 #ifdef LOCK_PROFILING_DEBUG_SPIN 685 bool is_spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK); 686 if ((spin && !is_spin) || (!spin && is_spin)) 687 printf("%s: lock %s spin mismatch (arg %d, flag %d)\n", __func__, 688 lo->lo_name, spin, is_spin); 689 #endif 690 691 if (lo->lo_flags & LO_NOPROFILE) 692 return; 693 head = &curthread->td_lprof[spin]; 694 if (LIST_FIRST(head) == NULL) 695 return; 696 if (SCHEDULER_STOPPED()) 697 return; 698 critical_enter(); 699 /* Recheck enabled now that we're in a critical section. */ 700 if (lock_prof_enable == 0 && lock_prof_resetting == 1) 701 goto out; 702 /* 703 * If lock profiling is not enabled we still want to remove the 704 * lpo from our queue. 705 */ 706 LIST_FOREACH(l, head, lpo_link) 707 if (l->lpo_obj == lo) 708 break; 709 if (l == NULL) 710 goto out; 711 if (--l->lpo_ref > 0) 712 goto out; 713 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line); 714 if (lp == NULL) 715 goto release; 716 curtime = nanoseconds(); 717 if (curtime < l->lpo_acqtime) 718 goto release; 719 holdtime = curtime - l->lpo_acqtime; 720 721 /* 722 * Record if the lock has been held longer now than ever 723 * before. 724 */ 725 if (holdtime > lp->cnt_max) 726 lp->cnt_max = holdtime; 727 if (l->lpo_waittime > lp->cnt_wait_max) 728 lp->cnt_wait_max = l->lpo_waittime; 729 lp->cnt_tot += holdtime; 730 lp->cnt_wait += l->lpo_waittime; 731 lp->cnt_contest_locking += l->lpo_contest_locking; 732 lp->cnt_cur += l->lpo_cnt; 733 release: 734 LIST_REMOVE(l, lpo_link); 735 type = &LP_CPU_SELF->lpc_types[spin]; 736 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link); 737 out: 738 /* 739 * Paired with cpus_fence_seq_cst(). 740 */ 741 atomic_thread_fence_rel(); 742 critical_exit(); 743 } 744 745 static SYSCTL_NODE(_debug_lock, OID_AUTO, prof, 746 CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 747 "lock profiling"); 748 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, 749 &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); 750 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, 751 &lock_prof_rejected, 0, "Number of rejected profiling records"); 752 SYSCTL_INT(_debug_lock_prof, OID_AUTO, contested_only, CTLFLAG_RW, 753 &lock_contested_only, 0, "Only profile contested acquires"); 754 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, 755 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, 756 dump_lock_prof_stats, "A", 757 "Lock profiling statistics"); 758 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, 759 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0, 760 reset_lock_prof_stats, "I", 761 "Reset lock profiling statistics"); 762 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, 763 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, 764 enable_lock_prof, "I", 765 "Enable lock profiling"); 766 767 #endif 768