kern_lock.c revision 255940
1139804Simp/*- 2177957Sattilio * Copyright (c) 2008 Attilio Rao <attilio@FreeBSD.org> 3177957Sattilio * All rights reserved. 424269Speter * 524269Speter * Redistribution and use in source and binary forms, with or without 624269Speter * modification, are permitted provided that the following conditions 724269Speter * are met: 824269Speter * 1. Redistributions of source code must retain the above copyright 9177957Sattilio * notice(s), this list of conditions and the following disclaimer as 10177957Sattilio * the first lines of this file unmodified other than the possible 11177957Sattilio * addition of one or more copyright notices. 1224269Speter * 2. Redistributions in binary form must reproduce the above copyright 13177957Sattilio * notice(s), this list of conditions and the following disclaimer in the 1424269Speter * documentation and/or other materials provided with the distribution. 1524269Speter * 16177957Sattilio * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 17177957Sattilio * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 18177957Sattilio * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 19177957Sattilio * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 20177957Sattilio * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 21177957Sattilio * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 22177957Sattilio * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 23177957Sattilio * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2424269Speter * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25177957Sattilio * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 26177957Sattilio * DAMAGE. 2724269Speter */ 2824269Speter 29194317Sattilio#include "opt_adaptive_lockmgrs.h" 30177957Sattilio#include "opt_ddb.h" 31233628Sfabient#include "opt_hwpmc_hooks.h" 32192853Ssson#include "opt_kdtrace.h" 33177957Sattilio 34116182Sobrien#include <sys/cdefs.h> 35116182Sobrien__FBSDID("$FreeBSD: head/sys/kern/kern_lock.c 255940 2013-09-29 18:02:23Z kib $"); 36116182Sobrien 3724269Speter#include <sys/param.h> 38244582Sattilio#include <sys/kdb.h> 3984812Sjhb#include <sys/ktr.h> 4024269Speter#include <sys/lock.h> 41177957Sattilio#include <sys/lock_profile.h> 42102477Sbde#include <sys/lockmgr.h> 4367353Sjhb#include <sys/mutex.h> 44102477Sbde#include <sys/proc.h> 45177957Sattilio#include <sys/sleepqueue.h> 46148668Sjeff#ifdef DEBUG_LOCKS 47148668Sjeff#include <sys/stack.h> 48148668Sjeff#endif 49194317Sattilio#include <sys/sysctl.h> 50177957Sattilio#include <sys/systm.h> 5124269Speter 52177957Sattilio#include <machine/cpu.h> 53176014Sattilio 54161322Sjhb#ifdef DDB 55161322Sjhb#include <ddb/ddb.h> 56161322Sjhb#endif 57161322Sjhb 58233628Sfabient#ifdef HWPMC_HOOKS 59233628Sfabient#include <sys/pmckern.h> 60233628SfabientPMC_SOFT_DECLARE( , , lock, failed); 61233628Sfabient#endif 62233628Sfabient 63194317SattilioCTASSERT(((LK_ADAPTIVE | LK_NOSHARE) & LO_CLASSFLAGS) == 64194317Sattilio (LK_ADAPTIVE | LK_NOSHARE)); 65194317SattilioCTASSERT(LK_UNLOCKED == (LK_UNLOCKED & 66194317Sattilio ~(LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS))); 67177957Sattilio 68177957Sattilio#define SQ_EXCLUSIVE_QUEUE 0 69177957Sattilio#define SQ_SHARED_QUEUE 1 70177957Sattilio 71177957Sattilio#ifndef INVARIANTS 72177957Sattilio#define _lockmgr_assert(lk, what, file, line) 73177957Sattilio#define TD_LOCKS_INC(td) 74177957Sattilio#define TD_LOCKS_DEC(td) 75177957Sattilio#else 76177957Sattilio#define TD_LOCKS_INC(td) ((td)->td_locks++) 77177957Sattilio#define TD_LOCKS_DEC(td) ((td)->td_locks--) 78177957Sattilio#endif 79177957Sattilio#define TD_SLOCKS_INC(td) ((td)->td_lk_slocks++) 80177957Sattilio#define TD_SLOCKS_DEC(td) ((td)->td_lk_slocks--) 81177957Sattilio 82177957Sattilio#ifndef DEBUG_LOCKS 83177957Sattilio#define STACK_PRINT(lk) 84177957Sattilio#define STACK_SAVE(lk) 85177957Sattilio#define STACK_ZERO(lk) 86177957Sattilio#else 87177957Sattilio#define STACK_PRINT(lk) stack_print_ddb(&(lk)->lk_stack) 88177957Sattilio#define STACK_SAVE(lk) stack_save(&(lk)->lk_stack) 89177957Sattilio#define STACK_ZERO(lk) stack_zero(&(lk)->lk_stack) 90177957Sattilio#endif 91177957Sattilio 92177957Sattilio#define LOCK_LOG2(lk, string, arg1, arg2) \ 93177957Sattilio if (LOCK_LOG_TEST(&(lk)->lock_object, 0)) \ 94177957Sattilio CTR2(KTR_LOCK, (string), (arg1), (arg2)) 95177957Sattilio#define LOCK_LOG3(lk, string, arg1, arg2, arg3) \ 96177957Sattilio if (LOCK_LOG_TEST(&(lk)->lock_object, 0)) \ 97177957Sattilio CTR3(KTR_LOCK, (string), (arg1), (arg2), (arg3)) 98177957Sattilio 99178159Sattilio#define GIANT_DECLARE \ 100178159Sattilio int _i = 0; \ 101178159Sattilio WITNESS_SAVE_DECL(Giant) 102178159Sattilio#define GIANT_RESTORE() do { \ 103178159Sattilio if (_i > 0) { \ 104178159Sattilio while (_i--) \ 105178159Sattilio mtx_lock(&Giant); \ 106178159Sattilio WITNESS_RESTORE(&Giant.lock_object, Giant); \ 107178159Sattilio } \ 108178159Sattilio} while (0) 109178159Sattilio#define GIANT_SAVE() do { \ 110178159Sattilio if (mtx_owned(&Giant)) { \ 111178159Sattilio WITNESS_SAVE(&Giant.lock_object, Giant); \ 112178159Sattilio while (mtx_owned(&Giant)) { \ 113178159Sattilio _i++; \ 114178159Sattilio mtx_unlock(&Giant); \ 115178159Sattilio } \ 116178159Sattilio } \ 117178159Sattilio} while (0) 118178159Sattilio 119177957Sattilio#define LK_CAN_SHARE(x) \ 120177957Sattilio (((x) & LK_SHARE) && (((x) & LK_EXCLUSIVE_WAITERS) == 0 || \ 121194317Sattilio ((x) & LK_EXCLUSIVE_SPINNERS) == 0 || \ 122177982Sattilio curthread->td_lk_slocks || (curthread->td_pflags & TDP_DEADLKTREAT))) 123178159Sattilio#define LK_TRYOP(x) \ 124178159Sattilio ((x) & LK_NOWAIT) 125177957Sattilio 126178159Sattilio#define LK_CAN_WITNESS(x) \ 127178159Sattilio (((x) & LK_NOWITNESS) == 0 && !LK_TRYOP(x)) 128178159Sattilio#define LK_TRYWIT(x) \ 129178159Sattilio (LK_TRYOP(x) ? LOP_TRYLOCK : 0) 130178159Sattilio 131194317Sattilio#define LK_CAN_ADAPT(lk, f) \ 132194317Sattilio (((lk)->lock_object.lo_flags & LK_ADAPTIVE) != 0 && \ 133194317Sattilio ((f) & LK_SLEEPFAIL) == 0) 134194317Sattilio 135177957Sattilio#define lockmgr_disowned(lk) \ 136177957Sattilio (((lk)->lk_lock & ~(LK_FLAGMASK & ~LK_SHARE)) == LK_KERNPROC) 137177957Sattilio 138177957Sattilio#define lockmgr_xlocked(lk) \ 139177957Sattilio (((lk)->lk_lock & ~(LK_FLAGMASK & ~LK_SHARE)) == (uintptr_t)curthread) 140177957Sattilio 141227588Spjdstatic void assert_lockmgr(const struct lock_object *lock, int how); 142177957Sattilio#ifdef DDB 143227588Spjdstatic void db_show_lockmgr(const struct lock_object *lock); 144177957Sattilio#endif 145255745Sdavidestatic void lock_lockmgr(struct lock_object *lock, uintptr_t how); 146192853Ssson#ifdef KDTRACE_HOOKS 147227588Spjdstatic int owner_lockmgr(const struct lock_object *lock, 148227588Spjd struct thread **owner); 149192853Ssson#endif 150255745Sdavidestatic uintptr_t unlock_lockmgr(struct lock_object *lock); 151177957Sattilio 152164246Skmacystruct lock_class lock_class_lockmgr = { 153167366Sjhb .lc_name = "lockmgr", 154177957Sattilio .lc_flags = LC_RECURSABLE | LC_SLEEPABLE | LC_SLEEPLOCK | LC_UPGRADABLE, 155173733Sattilio .lc_assert = assert_lockmgr, 156164246Skmacy#ifdef DDB 157167368Sjhb .lc_ddb_show = db_show_lockmgr, 158164246Skmacy#endif 159167368Sjhb .lc_lock = lock_lockmgr, 160192853Ssson .lc_unlock = unlock_lockmgr, 161192853Ssson#ifdef KDTRACE_HOOKS 162192853Ssson .lc_owner = owner_lockmgr, 163192853Ssson#endif 164164246Skmacy}; 165164246Skmacy 166194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 167194317Sattiliostatic u_int alk_retries = 10; 168194317Sattiliostatic u_int alk_loops = 10000; 169227309Sedstatic SYSCTL_NODE(_debug, OID_AUTO, lockmgr, CTLFLAG_RD, NULL, 170227309Sed "lockmgr debugging"); 171194317SattilioSYSCTL_UINT(_debug_lockmgr, OID_AUTO, retries, CTLFLAG_RW, &alk_retries, 0, ""); 172194317SattilioSYSCTL_UINT(_debug_lockmgr, OID_AUTO, loops, CTLFLAG_RW, &alk_loops, 0, ""); 173194317Sattilio#endif 174194317Sattilio 175177957Sattiliostatic __inline struct thread * 176227588Spjdlockmgr_xholder(const struct lock *lk) 177177957Sattilio{ 178177957Sattilio uintptr_t x; 179176249Sattilio 180177957Sattilio x = lk->lk_lock; 181177957Sattilio return ((x & LK_SHARE) ? NULL : (struct thread *)LK_HOLDER(x)); 182177957Sattilio} 183177957Sattilio 18424269Speter/* 185177957Sattilio * It assumes sleepq_lock held and returns with this one unheld. 186177957Sattilio * It also assumes the generic interlock is sane and previously checked. 187177957Sattilio * If LK_INTERLOCK is specified the interlock is not reacquired after the 188177957Sattilio * sleep. 18924269Speter */ 190177957Sattiliostatic __inline int 191177957Sattiliosleeplk(struct lock *lk, u_int flags, struct lock_object *ilk, 192177957Sattilio const char *wmesg, int pri, int timo, int queue) 193177957Sattilio{ 194178159Sattilio GIANT_DECLARE; 195177957Sattilio struct lock_class *class; 196177957Sattilio int catch, error; 19724269Speter 198177957Sattilio class = (flags & LK_INTERLOCK) ? LOCK_CLASS(ilk) : NULL; 199179306Sattilio catch = pri & PCATCH; 200177957Sattilio pri &= PRIMASK; 201177957Sattilio error = 0; 202177957Sattilio 203177957Sattilio LOCK_LOG3(lk, "%s: %p blocking on the %s sleepqueue", __func__, lk, 204177957Sattilio (queue == SQ_EXCLUSIVE_QUEUE) ? "exclusive" : "shared"); 205177957Sattilio 206177957Sattilio if (flags & LK_INTERLOCK) 207177957Sattilio class->lc_unlock(ilk); 208200447Sattilio if (queue == SQ_EXCLUSIVE_QUEUE && (flags & LK_SLEEPFAIL) != 0) 209200447Sattilio lk->lk_exslpfail++; 210178159Sattilio GIANT_SAVE(); 211177957Sattilio sleepq_add(&lk->lock_object, NULL, wmesg, SLEEPQ_LK | (catch ? 212177957Sattilio SLEEPQ_INTERRUPTIBLE : 0), queue); 213177957Sattilio if ((flags & LK_TIMELOCK) && timo) 214177957Sattilio sleepq_set_timeout(&lk->lock_object, timo); 215177957Sattilio 216177957Sattilio /* 217177957Sattilio * Decisional switch for real sleeping. 218177957Sattilio */ 219177957Sattilio if ((flags & LK_TIMELOCK) && timo && catch) 220177957Sattilio error = sleepq_timedwait_sig(&lk->lock_object, pri); 221177957Sattilio else if ((flags & LK_TIMELOCK) && timo) 222177957Sattilio error = sleepq_timedwait(&lk->lock_object, pri); 223177957Sattilio else if (catch) 224177957Sattilio error = sleepq_wait_sig(&lk->lock_object, pri); 225177957Sattilio else 226177957Sattilio sleepq_wait(&lk->lock_object, pri); 227178159Sattilio GIANT_RESTORE(); 228177957Sattilio if ((flags & LK_SLEEPFAIL) && error == 0) 229177957Sattilio error = ENOLCK; 230177957Sattilio 231177957Sattilio return (error); 232177957Sattilio} 233177957Sattilio 234181334Sjhbstatic __inline int 235177957Sattiliowakeupshlk(struct lock *lk, const char *file, int line) 236177957Sattilio{ 237177957Sattilio uintptr_t v, x; 238200447Sattilio u_int realexslp; 239181334Sjhb int queue, wakeup_swapper; 240177957Sattilio 241178159Sattilio WITNESS_UNLOCK(&lk->lock_object, 0, file, line); 242177957Sattilio LOCK_LOG_LOCK("SUNLOCK", &lk->lock_object, 0, 0, file, line); 243177957Sattilio 244181334Sjhb wakeup_swapper = 0; 245177957Sattilio for (;;) { 246177957Sattilio x = lk->lk_lock; 247177957Sattilio 248177957Sattilio /* 249177957Sattilio * If there is more than one shared lock held, just drop one 250177957Sattilio * and return. 251177957Sattilio */ 252177957Sattilio if (LK_SHARERS(x) > 1) { 253197735Sattilio if (atomic_cmpset_rel_ptr(&lk->lk_lock, x, 254177957Sattilio x - LK_ONE_SHARER)) 255177957Sattilio break; 256177957Sattilio continue; 257177957Sattilio } 258177957Sattilio 259177957Sattilio /* 260177957Sattilio * If there are not waiters on the exclusive queue, drop the 261177957Sattilio * lock quickly. 262177957Sattilio */ 263177957Sattilio if ((x & LK_ALL_WAITERS) == 0) { 264194317Sattilio MPASS((x & ~LK_EXCLUSIVE_SPINNERS) == 265194317Sattilio LK_SHARERS_LOCK(1)); 266197735Sattilio if (atomic_cmpset_rel_ptr(&lk->lk_lock, x, LK_UNLOCKED)) 267177957Sattilio break; 268177957Sattilio continue; 269177957Sattilio } 270177957Sattilio 271177957Sattilio /* 272177957Sattilio * We should have a sharer with waiters, so enter the hard 273177957Sattilio * path in order to handle wakeups correctly. 274177957Sattilio */ 275177957Sattilio sleepq_lock(&lk->lock_object); 276194317Sattilio x = lk->lk_lock & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); 277177957Sattilio v = LK_UNLOCKED; 278177957Sattilio 279177957Sattilio /* 280177957Sattilio * If the lock has exclusive waiters, give them preference in 281177957Sattilio * order to avoid deadlock with shared runners up. 282200447Sattilio * If interruptible sleeps left the exclusive queue empty 283200447Sattilio * avoid a starvation for the threads sleeping on the shared 284200447Sattilio * queue by giving them precedence and cleaning up the 285200447Sattilio * exclusive waiters bit anyway. 286201709Sattilio * Please note that lk_exslpfail count may be lying about 287201709Sattilio * the real number of waiters with the LK_SLEEPFAIL flag on 288201709Sattilio * because they may be used in conjuction with interruptible 289201710Sattilio * sleeps so lk_exslpfail might be considered an 'upper limit' 290201710Sattilio * bound, including the edge cases. 291177957Sattilio */ 292200447Sattilio realexslp = sleepq_sleepcnt(&lk->lock_object, 293200447Sattilio SQ_EXCLUSIVE_QUEUE); 294200447Sattilio if ((x & LK_EXCLUSIVE_WAITERS) != 0 && realexslp != 0) { 295200447Sattilio if (lk->lk_exslpfail < realexslp) { 296200447Sattilio lk->lk_exslpfail = 0; 297200447Sattilio queue = SQ_EXCLUSIVE_QUEUE; 298200447Sattilio v |= (x & LK_SHARED_WAITERS); 299200447Sattilio } else { 300200447Sattilio lk->lk_exslpfail = 0; 301200447Sattilio LOCK_LOG2(lk, 302200447Sattilio "%s: %p has only LK_SLEEPFAIL sleepers", 303200447Sattilio __func__, lk); 304200447Sattilio LOCK_LOG2(lk, 305200447Sattilio "%s: %p waking up threads on the exclusive queue", 306200447Sattilio __func__, lk); 307200447Sattilio wakeup_swapper = 308200447Sattilio sleepq_broadcast(&lk->lock_object, 309200447Sattilio SLEEPQ_LK, 0, SQ_EXCLUSIVE_QUEUE); 310200447Sattilio queue = SQ_SHARED_QUEUE; 311200447Sattilio } 312200447Sattilio 313177957Sattilio } else { 314201703Sattilio 315201703Sattilio /* 316201703Sattilio * Exclusive waiters sleeping with LK_SLEEPFAIL on 317201703Sattilio * and using interruptible sleeps/timeout may have 318201703Sattilio * left spourious lk_exslpfail counts on, so clean 319201703Sattilio * it up anyway. 320201703Sattilio */ 321201703Sattilio lk->lk_exslpfail = 0; 322177957Sattilio queue = SQ_SHARED_QUEUE; 323177957Sattilio } 324177957Sattilio 325197735Sattilio if (!atomic_cmpset_rel_ptr(&lk->lk_lock, LK_SHARERS_LOCK(1) | x, 326177957Sattilio v)) { 327177957Sattilio sleepq_release(&lk->lock_object); 328177957Sattilio continue; 329177957Sattilio } 330177957Sattilio LOCK_LOG3(lk, "%s: %p waking up threads on the %s queue", 331177957Sattilio __func__, lk, queue == SQ_SHARED_QUEUE ? "shared" : 332177957Sattilio "exclusive"); 333200447Sattilio wakeup_swapper |= sleepq_broadcast(&lk->lock_object, SLEEPQ_LK, 334181334Sjhb 0, queue); 335177957Sattilio sleepq_release(&lk->lock_object); 336177957Sattilio break; 337177957Sattilio } 338177957Sattilio 339177957Sattilio lock_profile_release_lock(&lk->lock_object); 340252212Sjhb TD_LOCKS_DEC(curthread); 341252212Sjhb TD_SLOCKS_DEC(curthread); 342181334Sjhb return (wakeup_swapper); 343177957Sattilio} 344177957Sattilio 345177957Sattiliostatic void 346227588Spjdassert_lockmgr(const struct lock_object *lock, int what) 347173733Sattilio{ 348173733Sattilio 349173733Sattilio panic("lockmgr locks do not support assertions"); 350173733Sattilio} 351173733Sattilio 352177957Sattiliostatic void 353255745Sdavidelock_lockmgr(struct lock_object *lock, uintptr_t how) 354167368Sjhb{ 355167368Sjhb 356167368Sjhb panic("lockmgr locks do not support sleep interlocking"); 357167368Sjhb} 358167368Sjhb 359255745Sdavidestatic uintptr_t 360167368Sjhbunlock_lockmgr(struct lock_object *lock) 361167368Sjhb{ 362167368Sjhb 363167368Sjhb panic("lockmgr locks do not support sleep interlocking"); 364167368Sjhb} 365167368Sjhb 366192853Ssson#ifdef KDTRACE_HOOKS 367192853Sssonstatic int 368227588Spjdowner_lockmgr(const struct lock_object *lock, struct thread **owner) 369192853Ssson{ 370192853Ssson 371192853Ssson panic("lockmgr locks do not support owner inquiring"); 372192853Ssson} 373192853Ssson#endif 374192853Ssson 375177957Sattiliovoid 376177957Sattiliolockinit(struct lock *lk, int pri, const char *wmesg, int timo, int flags) 377177957Sattilio{ 378177957Sattilio int iflags; 37929653Sdyson 380177957Sattilio MPASS((flags & ~LK_INIT_MASK) == 0); 381196334Sattilio ASSERT_ATOMIC_LOAD_PTR(lk->lk_lock, 382196334Sattilio ("%s: lockmgr not aligned for %s: %p", __func__, wmesg, 383196334Sattilio &lk->lk_lock)); 38424269Speter 385193307Sattilio iflags = LO_SLEEPABLE | LO_UPGRADABLE; 386193307Sattilio if (flags & LK_CANRECURSE) 387193307Sattilio iflags |= LO_RECURSABLE; 388177957Sattilio if ((flags & LK_NODUP) == 0) 389177957Sattilio iflags |= LO_DUPOK; 390177957Sattilio if (flags & LK_NOPROFILE) 391177957Sattilio iflags |= LO_NOPROFILE; 392177957Sattilio if ((flags & LK_NOWITNESS) == 0) 393177957Sattilio iflags |= LO_WITNESS; 394177957Sattilio if (flags & LK_QUIET) 395177957Sattilio iflags |= LO_QUIET; 396250411Smarcel if (flags & LK_IS_VNODE) 397250411Smarcel iflags |= LO_IS_VNODE; 398194317Sattilio iflags |= flags & (LK_ADAPTIVE | LK_NOSHARE); 399177957Sattilio 400252212Sjhb lock_init(&lk->lock_object, &lock_class_lockmgr, wmesg, NULL, iflags); 401177957Sattilio lk->lk_lock = LK_UNLOCKED; 402177957Sattilio lk->lk_recurse = 0; 403200447Sattilio lk->lk_exslpfail = 0; 404177957Sattilio lk->lk_timo = timo; 405177957Sattilio lk->lk_pri = pri; 406177957Sattilio STACK_ZERO(lk); 40728345Sdyson} 40824269Speter 409211531Sjhb/* 410211531Sjhb * XXX: Gross hacks to manipulate external lock flags after 411211531Sjhb * initialization. Used for certain vnode and buf locks. 412211531Sjhb */ 413177957Sattiliovoid 414211531Sjhblockallowshare(struct lock *lk) 415211531Sjhb{ 416211531Sjhb 417211531Sjhb lockmgr_assert(lk, KA_XLOCKED); 418211531Sjhb lk->lock_object.lo_flags &= ~LK_NOSHARE; 419211531Sjhb} 420211531Sjhb 421211531Sjhbvoid 422211531Sjhblockallowrecurse(struct lock *lk) 423211531Sjhb{ 424211531Sjhb 425211531Sjhb lockmgr_assert(lk, KA_XLOCKED); 426211531Sjhb lk->lock_object.lo_flags |= LO_RECURSABLE; 427211531Sjhb} 428211531Sjhb 429211531Sjhbvoid 430211531Sjhblockdisablerecurse(struct lock *lk) 431211531Sjhb{ 432211531Sjhb 433211531Sjhb lockmgr_assert(lk, KA_XLOCKED); 434211531Sjhb lk->lock_object.lo_flags &= ~LO_RECURSABLE; 435211531Sjhb} 436211531Sjhb 437211531Sjhbvoid 438177957Sattiliolockdestroy(struct lock *lk) 439177957Sattilio{ 44042453Seivind 441177957Sattilio KASSERT(lk->lk_lock == LK_UNLOCKED, ("lockmgr still held")); 442177957Sattilio KASSERT(lk->lk_recurse == 0, ("lockmgr still recursed")); 443200447Sattilio KASSERT(lk->lk_exslpfail == 0, ("lockmgr still exclusive waiters")); 444177957Sattilio lock_destroy(&lk->lock_object); 44528345Sdyson} 44628345Sdyson 447177957Sattilioint 448177957Sattilio__lockmgr_args(struct lock *lk, u_int flags, struct lock_object *ilk, 449177957Sattilio const char *wmesg, int pri, int timo, const char *file, int line) 450140711Sjeff{ 451178159Sattilio GIANT_DECLARE; 452177957Sattilio struct lock_class *class; 453176320Sattilio const char *iwmesg; 454177957Sattilio uintptr_t tid, v, x; 455200447Sattilio u_int op, realexslp; 456189846Sjeff int error, ipri, itimo, queue, wakeup_swapper; 457189846Sjeff#ifdef LOCK_PROFILING 458189846Sjeff uint64_t waittime = 0; 459189846Sjeff int contested = 0; 460189846Sjeff#endif 461194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 462194317Sattilio volatile struct thread *owner; 463194317Sattilio u_int i, spintries = 0; 464194317Sattilio#endif 465176320Sattilio 466177957Sattilio error = 0; 467177957Sattilio tid = (uintptr_t)curthread; 468177957Sattilio op = (flags & LK_TYPE_MASK); 469177957Sattilio iwmesg = (wmesg == LK_WMESG_DEFAULT) ? lk->lock_object.lo_name : wmesg; 470177957Sattilio ipri = (pri == LK_PRIO_DEFAULT) ? lk->lk_pri : pri; 471177957Sattilio itimo = (timo == LK_TIMO_DEFAULT) ? lk->lk_timo : timo; 472176320Sattilio 473177957Sattilio MPASS((flags & ~LK_TOTAL_MASK) == 0); 474178150Sattilio KASSERT((op & (op - 1)) == 0, 475178150Sattilio ("%s: Invalid requested operation @ %s:%d", __func__, file, line)); 476177957Sattilio KASSERT((flags & (LK_NOWAIT | LK_SLEEPFAIL)) == 0 || 477177957Sattilio (op != LK_DOWNGRADE && op != LK_RELEASE), 478177957Sattilio ("%s: Invalid flags in regard of the operation desired @ %s:%d", 479177957Sattilio __func__, file, line)); 480177957Sattilio KASSERT((flags & LK_INTERLOCK) == 0 || ilk != NULL, 481177957Sattilio ("%s: LK_INTERLOCK passed without valid interlock @ %s:%d", 482177957Sattilio __func__, file, line)); 483244582Sattilio KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread), 484240424Sattilio ("%s: idle thread %p on lockmgr %s @ %s:%d", __func__, curthread, 485240424Sattilio lk->lock_object.lo_name, file, line)); 48666615Sjasone 487177957Sattilio class = (flags & LK_INTERLOCK) ? LOCK_CLASS(ilk) : NULL; 488177957Sattilio if (panicstr != NULL) { 489177957Sattilio if (flags & LK_INTERLOCK) 490177957Sattilio class->lc_unlock(ilk); 491177957Sattilio return (0); 49228345Sdyson } 49328345Sdyson 494224581Skib if (lk->lock_object.lo_flags & LK_NOSHARE) { 495224581Skib switch (op) { 496224581Skib case LK_SHARED: 497224581Skib op = LK_EXCLUSIVE; 498224581Skib break; 499224581Skib case LK_UPGRADE: 500255940Skib case LK_TRYUPGRADE: 501224581Skib case LK_DOWNGRADE: 502224581Skib _lockmgr_assert(lk, KA_XLOCKED | KA_NOTRECURSED, 503224581Skib file, line); 504245113Smjg if (flags & LK_INTERLOCK) 505245113Smjg class->lc_unlock(ilk); 506224581Skib return (0); 507224581Skib } 508224581Skib } 509164159Skmacy 510181334Sjhb wakeup_swapper = 0; 511177957Sattilio switch (op) { 512177957Sattilio case LK_SHARED: 513178159Sattilio if (LK_CAN_WITNESS(flags)) 514178159Sattilio WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER, 515251326Sjhb file, line, flags & LK_INTERLOCK ? ilk : NULL); 516177957Sattilio for (;;) { 517177957Sattilio x = lk->lk_lock; 518174948Sattilio 519177957Sattilio /* 520177957Sattilio * If no other thread has an exclusive lock, or 521177957Sattilio * no exclusive waiter is present, bump the count of 522177957Sattilio * sharers. Since we have to preserve the state of 523177957Sattilio * waiters, if we fail to acquire the shared lock 524177957Sattilio * loop back and retry. 525177957Sattilio */ 526177957Sattilio if (LK_CAN_SHARE(x)) { 527177957Sattilio if (atomic_cmpset_acq_ptr(&lk->lk_lock, x, 528177957Sattilio x + LK_ONE_SHARER)) 529177957Sattilio break; 530177957Sattilio continue; 531177957Sattilio } 532233628Sfabient#ifdef HWPMC_HOOKS 533233628Sfabient PMC_SOFT_CALL( , , lock, failed); 534233628Sfabient#endif 535177957Sattilio lock_profile_obtain_lock_failed(&lk->lock_object, 536177957Sattilio &contested, &waittime); 53728345Sdyson 538177957Sattilio /* 539180798Skib * If the lock is already held by curthread in 540177957Sattilio * exclusive way avoid a deadlock. 541177957Sattilio */ 542177957Sattilio if (LK_HOLDER(x) == tid) { 543177957Sattilio LOCK_LOG2(lk, 544180798Skib "%s: %p already held in exclusive mode", 545177957Sattilio __func__, lk); 546177957Sattilio error = EDEADLK; 547177957Sattilio break; 548177957Sattilio } 549140711Sjeff 550177957Sattilio /* 551177957Sattilio * If the lock is expected to not sleep just give up 552177957Sattilio * and return. 553177957Sattilio */ 554177957Sattilio if (LK_TRYOP(flags)) { 555177957Sattilio LOCK_LOG2(lk, "%s: %p fails the try operation", 556177957Sattilio __func__, lk); 557177957Sattilio error = EBUSY; 558177957Sattilio break; 559177957Sattilio } 56028345Sdyson 561194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 562177957Sattilio /* 563194317Sattilio * If the owner is running on another CPU, spin until 564194317Sattilio * the owner stops running or the state of the lock 565196772Sattilio * changes. We need a double-state handle here 566196772Sattilio * because for a failed acquisition the lock can be 567196772Sattilio * either held in exclusive mode or shared mode 568196772Sattilio * (for the writer starvation avoidance technique). 569194317Sattilio */ 570194317Sattilio if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 571194317Sattilio LK_HOLDER(x) != LK_KERNPROC) { 572194317Sattilio owner = (struct thread *)LK_HOLDER(x); 573194317Sattilio if (LOCK_LOG_TEST(&lk->lock_object, 0)) 574194317Sattilio CTR3(KTR_LOCK, 575194317Sattilio "%s: spinning on %p held by %p", 576194317Sattilio __func__, lk, owner); 577194317Sattilio 578194317Sattilio /* 579194317Sattilio * If we are holding also an interlock drop it 580194317Sattilio * in order to avoid a deadlock if the lockmgr 581194317Sattilio * owner is adaptively spinning on the 582194317Sattilio * interlock itself. 583194317Sattilio */ 584194317Sattilio if (flags & LK_INTERLOCK) { 585194317Sattilio class->lc_unlock(ilk); 586194317Sattilio flags &= ~LK_INTERLOCK; 587194317Sattilio } 588194317Sattilio GIANT_SAVE(); 589194317Sattilio while (LK_HOLDER(lk->lk_lock) == 590194317Sattilio (uintptr_t)owner && TD_IS_RUNNING(owner)) 591194317Sattilio cpu_spinwait(); 592196772Sattilio GIANT_RESTORE(); 593196772Sattilio continue; 594194317Sattilio } else if (LK_CAN_ADAPT(lk, flags) && 595196772Sattilio (x & LK_SHARE) != 0 && LK_SHARERS(x) && 596194317Sattilio spintries < alk_retries) { 597194317Sattilio if (flags & LK_INTERLOCK) { 598194317Sattilio class->lc_unlock(ilk); 599194317Sattilio flags &= ~LK_INTERLOCK; 600194317Sattilio } 601194317Sattilio GIANT_SAVE(); 602194317Sattilio spintries++; 603194317Sattilio for (i = 0; i < alk_loops; i++) { 604194317Sattilio if (LOCK_LOG_TEST(&lk->lock_object, 0)) 605194317Sattilio CTR4(KTR_LOCK, 606194317Sattilio "%s: shared spinning on %p with %u and %u", 607194317Sattilio __func__, lk, spintries, i); 608194317Sattilio x = lk->lk_lock; 609194317Sattilio if ((x & LK_SHARE) == 0 || 610194317Sattilio LK_CAN_SHARE(x) != 0) 611194317Sattilio break; 612194317Sattilio cpu_spinwait(); 613194317Sattilio } 614196772Sattilio GIANT_RESTORE(); 615194317Sattilio if (i != alk_loops) 616194317Sattilio continue; 617194317Sattilio } 618194317Sattilio#endif 619194317Sattilio 620194317Sattilio /* 621177957Sattilio * Acquire the sleepqueue chain lock because we 622177957Sattilio * probabilly will need to manipulate waiters flags. 623177957Sattilio */ 624177957Sattilio sleepq_lock(&lk->lock_object); 625177957Sattilio x = lk->lk_lock; 626111463Sjeff 627177957Sattilio /* 628177957Sattilio * if the lock can be acquired in shared mode, try 629177957Sattilio * again. 630177957Sattilio */ 631177957Sattilio if (LK_CAN_SHARE(x)) { 632177957Sattilio sleepq_release(&lk->lock_object); 633177957Sattilio continue; 634177957Sattilio } 63524269Speter 636194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 637177957Sattilio /* 638194317Sattilio * The current lock owner might have started executing 639194317Sattilio * on another CPU (or the lock could have changed 640194317Sattilio * owner) while we were waiting on the turnstile 641194317Sattilio * chain lock. If so, drop the turnstile lock and try 642194317Sattilio * again. 643194317Sattilio */ 644194317Sattilio if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 645194317Sattilio LK_HOLDER(x) != LK_KERNPROC) { 646194317Sattilio owner = (struct thread *)LK_HOLDER(x); 647194317Sattilio if (TD_IS_RUNNING(owner)) { 648194317Sattilio sleepq_release(&lk->lock_object); 649194317Sattilio continue; 650194317Sattilio } 651194317Sattilio } 652194317Sattilio#endif 653194317Sattilio 654194317Sattilio /* 655177957Sattilio * Try to set the LK_SHARED_WAITERS flag. If we fail, 656177957Sattilio * loop back and retry. 657177957Sattilio */ 658177957Sattilio if ((x & LK_SHARED_WAITERS) == 0) { 659177957Sattilio if (!atomic_cmpset_acq_ptr(&lk->lk_lock, x, 660177957Sattilio x | LK_SHARED_WAITERS)) { 661177957Sattilio sleepq_release(&lk->lock_object); 662177957Sattilio continue; 663177957Sattilio } 664177957Sattilio LOCK_LOG2(lk, "%s: %p set shared waiters flag", 665177957Sattilio __func__, lk); 666177957Sattilio } 66724269Speter 668177957Sattilio /* 669177957Sattilio * As far as we have been unable to acquire the 670177957Sattilio * shared lock and the shared waiters flag is set, 671177957Sattilio * we will sleep. 672177957Sattilio */ 673177957Sattilio error = sleeplk(lk, flags, ilk, iwmesg, ipri, itimo, 674177957Sattilio SQ_SHARED_QUEUE); 675177957Sattilio flags &= ~LK_INTERLOCK; 676177957Sattilio if (error) { 677177957Sattilio LOCK_LOG3(lk, 678177957Sattilio "%s: interrupted sleep for %p with %d", 679177957Sattilio __func__, lk, error); 680177957Sattilio break; 681177957Sattilio } 682177957Sattilio LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", 683177957Sattilio __func__, lk); 684177957Sattilio } 685177957Sattilio if (error == 0) { 686177957Sattilio lock_profile_obtain_lock_success(&lk->lock_object, 687177957Sattilio contested, waittime, file, line); 688177957Sattilio LOCK_LOG_LOCK("SLOCK", &lk->lock_object, 0, 0, file, 689176014Sattilio line); 690178159Sattilio WITNESS_LOCK(&lk->lock_object, LK_TRYWIT(flags), file, 691178159Sattilio line); 692177957Sattilio TD_LOCKS_INC(curthread); 693177957Sattilio TD_SLOCKS_INC(curthread); 694177957Sattilio STACK_SAVE(lk); 695177957Sattilio } 696177957Sattilio break; 697177957Sattilio case LK_UPGRADE: 698255940Skib case LK_TRYUPGRADE: 699177957Sattilio _lockmgr_assert(lk, KA_SLOCKED, file, line); 700194317Sattilio v = lk->lk_lock; 701194317Sattilio x = v & LK_ALL_WAITERS; 702194317Sattilio v &= LK_EXCLUSIVE_SPINNERS; 703177957Sattilio 70444681Sjulian /* 705177957Sattilio * Try to switch from one shared lock to an exclusive one. 706177957Sattilio * We need to preserve waiters flags during the operation. 70744681Sjulian */ 708194317Sattilio if (atomic_cmpset_ptr(&lk->lk_lock, LK_SHARERS_LOCK(1) | x | v, 709177957Sattilio tid | x)) { 710177957Sattilio LOCK_LOG_LOCK("XUPGRADE", &lk->lock_object, 0, 0, file, 711177957Sattilio line); 712178159Sattilio WITNESS_UPGRADE(&lk->lock_object, LOP_EXCLUSIVE | 713178159Sattilio LK_TRYWIT(flags), file, line); 714177957Sattilio TD_SLOCKS_DEC(curthread); 71524269Speter break; 71624269Speter } 717177957Sattilio 71824269Speter /* 719255940Skib * In LK_TRYUPGRADE mode, do not drop the lock, 720255940Skib * returning EBUSY instead. 721255940Skib */ 722255940Skib if (op == LK_TRYUPGRADE) { 723255940Skib LOCK_LOG2(lk, "%s: %p failed the nowait upgrade", 724255940Skib __func__, lk); 725255940Skib error = EBUSY; 726255940Skib break; 727255940Skib } 728255940Skib 729255940Skib /* 730177957Sattilio * We have been unable to succeed in upgrading, so just 731177957Sattilio * give up the shared lock. 73224269Speter */ 733182010Sjhb wakeup_swapper |= wakeupshlk(lk, file, line); 73424269Speter 735177957Sattilio /* FALLTHROUGH */ 736177957Sattilio case LK_EXCLUSIVE: 737178159Sattilio if (LK_CAN_WITNESS(flags)) 738178159Sattilio WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER | 739251326Sjhb LOP_EXCLUSIVE, file, line, flags & LK_INTERLOCK ? 740251326Sjhb ilk : NULL); 74124269Speter 74224269Speter /* 743180798Skib * If curthread already holds the lock and this one is 744177957Sattilio * allowed to recurse, simply recurse on it. 74524269Speter */ 746177957Sattilio if (lockmgr_xlocked(lk)) { 747177957Sattilio if ((flags & LK_CANRECURSE) == 0 && 748193307Sattilio (lk->lock_object.lo_flags & LO_RECURSABLE) == 0) { 749177957Sattilio 750177957Sattilio /* 751177957Sattilio * If the lock is expected to not panic just 752177957Sattilio * give up and return. 753177957Sattilio */ 754177957Sattilio if (LK_TRYOP(flags)) { 755177957Sattilio LOCK_LOG2(lk, 756177957Sattilio "%s: %p fails the try operation", 757177957Sattilio __func__, lk); 758177957Sattilio error = EBUSY; 759177957Sattilio break; 760177957Sattilio } 761177957Sattilio if (flags & LK_INTERLOCK) 762177957Sattilio class->lc_unlock(ilk); 763177957Sattilio panic("%s: recursing on non recursive lockmgr %s @ %s:%d\n", 764177957Sattilio __func__, iwmesg, file, line); 765177957Sattilio } 766177957Sattilio lk->lk_recurse++; 767177957Sattilio LOCK_LOG2(lk, "%s: %p recursing", __func__, lk); 768177957Sattilio LOCK_LOG_LOCK("XLOCK", &lk->lock_object, 0, 769177957Sattilio lk->lk_recurse, file, line); 770178159Sattilio WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | 771178159Sattilio LK_TRYWIT(flags), file, line); 772177957Sattilio TD_LOCKS_INC(curthread); 77324269Speter break; 77424269Speter } 775177957Sattilio 776177957Sattilio while (!atomic_cmpset_acq_ptr(&lk->lk_lock, LK_UNLOCKED, 777177957Sattilio tid)) { 778233628Sfabient#ifdef HWPMC_HOOKS 779233628Sfabient PMC_SOFT_CALL( , , lock, failed); 780233628Sfabient#endif 781177957Sattilio lock_profile_obtain_lock_failed(&lk->lock_object, 782177957Sattilio &contested, &waittime); 783177957Sattilio 78424269Speter /* 785177957Sattilio * If the lock is expected to not sleep just give up 786177957Sattilio * and return. 78724269Speter */ 788177957Sattilio if (LK_TRYOP(flags)) { 789177957Sattilio LOCK_LOG2(lk, "%s: %p fails the try operation", 790177957Sattilio __func__, lk); 791177957Sattilio error = EBUSY; 792177957Sattilio break; 793177957Sattilio } 79434194Sdyson 795194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 796177957Sattilio /* 797194317Sattilio * If the owner is running on another CPU, spin until 798194317Sattilio * the owner stops running or the state of the lock 799194317Sattilio * changes. 800194317Sattilio */ 801194317Sattilio x = lk->lk_lock; 802194317Sattilio if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 803194317Sattilio LK_HOLDER(x) != LK_KERNPROC) { 804194317Sattilio owner = (struct thread *)LK_HOLDER(x); 805194317Sattilio if (LOCK_LOG_TEST(&lk->lock_object, 0)) 806194317Sattilio CTR3(KTR_LOCK, 807194317Sattilio "%s: spinning on %p held by %p", 808194317Sattilio __func__, lk, owner); 809194317Sattilio 810194317Sattilio /* 811194317Sattilio * If we are holding also an interlock drop it 812194317Sattilio * in order to avoid a deadlock if the lockmgr 813194317Sattilio * owner is adaptively spinning on the 814194317Sattilio * interlock itself. 815194317Sattilio */ 816194317Sattilio if (flags & LK_INTERLOCK) { 817194317Sattilio class->lc_unlock(ilk); 818194317Sattilio flags &= ~LK_INTERLOCK; 819194317Sattilio } 820194317Sattilio GIANT_SAVE(); 821194317Sattilio while (LK_HOLDER(lk->lk_lock) == 822194317Sattilio (uintptr_t)owner && TD_IS_RUNNING(owner)) 823194317Sattilio cpu_spinwait(); 824196772Sattilio GIANT_RESTORE(); 825196772Sattilio continue; 826194317Sattilio } else if (LK_CAN_ADAPT(lk, flags) && 827194317Sattilio (x & LK_SHARE) != 0 && LK_SHARERS(x) && 828194317Sattilio spintries < alk_retries) { 829194317Sattilio if ((x & LK_EXCLUSIVE_SPINNERS) == 0 && 830194317Sattilio !atomic_cmpset_ptr(&lk->lk_lock, x, 831194317Sattilio x | LK_EXCLUSIVE_SPINNERS)) 832194317Sattilio continue; 833194317Sattilio if (flags & LK_INTERLOCK) { 834194317Sattilio class->lc_unlock(ilk); 835194317Sattilio flags &= ~LK_INTERLOCK; 836194317Sattilio } 837194317Sattilio GIANT_SAVE(); 838194317Sattilio spintries++; 839194317Sattilio for (i = 0; i < alk_loops; i++) { 840194317Sattilio if (LOCK_LOG_TEST(&lk->lock_object, 0)) 841194317Sattilio CTR4(KTR_LOCK, 842194317Sattilio "%s: shared spinning on %p with %u and %u", 843194317Sattilio __func__, lk, spintries, i); 844194317Sattilio if ((lk->lk_lock & 845194317Sattilio LK_EXCLUSIVE_SPINNERS) == 0) 846194317Sattilio break; 847194317Sattilio cpu_spinwait(); 848194317Sattilio } 849196772Sattilio GIANT_RESTORE(); 850194317Sattilio if (i != alk_loops) 851194317Sattilio continue; 852194317Sattilio } 853194317Sattilio#endif 854194317Sattilio 855194317Sattilio /* 856177957Sattilio * Acquire the sleepqueue chain lock because we 857177957Sattilio * probabilly will need to manipulate waiters flags. 858177957Sattilio */ 859177957Sattilio sleepq_lock(&lk->lock_object); 860177957Sattilio x = lk->lk_lock; 861177957Sattilio 862177957Sattilio /* 863177957Sattilio * if the lock has been released while we spun on 864177957Sattilio * the sleepqueue chain lock just try again. 865177957Sattilio */ 866177957Sattilio if (x == LK_UNLOCKED) { 867177957Sattilio sleepq_release(&lk->lock_object); 868177957Sattilio continue; 869134365Skan } 87024269Speter 871194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 87224269Speter /* 873194317Sattilio * The current lock owner might have started executing 874194317Sattilio * on another CPU (or the lock could have changed 875194317Sattilio * owner) while we were waiting on the turnstile 876194317Sattilio * chain lock. If so, drop the turnstile lock and try 877194317Sattilio * again. 878194317Sattilio */ 879194317Sattilio if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 880194317Sattilio LK_HOLDER(x) != LK_KERNPROC) { 881194317Sattilio owner = (struct thread *)LK_HOLDER(x); 882194317Sattilio if (TD_IS_RUNNING(owner)) { 883194317Sattilio sleepq_release(&lk->lock_object); 884194317Sattilio continue; 885194317Sattilio } 886194317Sattilio } 887194317Sattilio#endif 888194317Sattilio 889194317Sattilio /* 890177957Sattilio * The lock can be in the state where there is a 891177957Sattilio * pending queue of waiters, but still no owner. 892177957Sattilio * This happens when the lock is contested and an 893177957Sattilio * owner is going to claim the lock. 894177957Sattilio * If curthread is the one successfully acquiring it 895177957Sattilio * claim lock ownership and return, preserving waiters 896177957Sattilio * flags. 89724269Speter */ 898194317Sattilio v = x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); 899194317Sattilio if ((x & ~v) == LK_UNLOCKED) { 900194317Sattilio v &= ~LK_EXCLUSIVE_SPINNERS; 901177957Sattilio if (atomic_cmpset_acq_ptr(&lk->lk_lock, x, 902177957Sattilio tid | v)) { 903177957Sattilio sleepq_release(&lk->lock_object); 904177957Sattilio LOCK_LOG2(lk, 905177957Sattilio "%s: %p claimed by a new writer", 906177957Sattilio __func__, lk); 907177957Sattilio break; 908177957Sattilio } 909177957Sattilio sleepq_release(&lk->lock_object); 910177957Sattilio continue; 911177957Sattilio } 912177957Sattilio 913177957Sattilio /* 914177957Sattilio * Try to set the LK_EXCLUSIVE_WAITERS flag. If we 915177957Sattilio * fail, loop back and retry. 916177957Sattilio */ 917177957Sattilio if ((x & LK_EXCLUSIVE_WAITERS) == 0) { 918177957Sattilio if (!atomic_cmpset_ptr(&lk->lk_lock, x, 919177957Sattilio x | LK_EXCLUSIVE_WAITERS)) { 920177957Sattilio sleepq_release(&lk->lock_object); 921177957Sattilio continue; 922177957Sattilio } 923177957Sattilio LOCK_LOG2(lk, "%s: %p set excl waiters flag", 924177957Sattilio __func__, lk); 925177957Sattilio } 926177957Sattilio 927177957Sattilio /* 928177957Sattilio * As far as we have been unable to acquire the 929177957Sattilio * exclusive lock and the exclusive waiters flag 930177957Sattilio * is set, we will sleep. 931177957Sattilio */ 932177957Sattilio error = sleeplk(lk, flags, ilk, iwmesg, ipri, itimo, 933177957Sattilio SQ_EXCLUSIVE_QUEUE); 934177957Sattilio flags &= ~LK_INTERLOCK; 935177957Sattilio if (error) { 936177957Sattilio LOCK_LOG3(lk, 937177957Sattilio "%s: interrupted sleep for %p with %d", 938177957Sattilio __func__, lk, error); 93948301Smckusick break; 94048301Smckusick } 941177957Sattilio LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", 942177957Sattilio __func__, lk); 94324269Speter } 944177957Sattilio if (error == 0) { 945177957Sattilio lock_profile_obtain_lock_success(&lk->lock_object, 946177957Sattilio contested, waittime, file, line); 947177957Sattilio LOCK_LOG_LOCK("XLOCK", &lk->lock_object, 0, 948177957Sattilio lk->lk_recurse, file, line); 949178159Sattilio WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | 950178159Sattilio LK_TRYWIT(flags), file, line); 951177957Sattilio TD_LOCKS_INC(curthread); 952177957Sattilio STACK_SAVE(lk); 953177957Sattilio } 954177957Sattilio break; 955177957Sattilio case LK_DOWNGRADE: 956243900Sattilio _lockmgr_assert(lk, KA_XLOCKED, file, line); 957178159Sattilio LOCK_LOG_LOCK("XDOWNGRADE", &lk->lock_object, 0, 0, file, line); 958178159Sattilio WITNESS_DOWNGRADE(&lk->lock_object, 0, file, line); 959243900Sattilio 960243900Sattilio /* 961243900Sattilio * Panic if the lock is recursed. 962243900Sattilio */ 963243900Sattilio if (lockmgr_xlocked(lk) && lockmgr_recursed(lk)) { 964243900Sattilio if (flags & LK_INTERLOCK) 965243900Sattilio class->lc_unlock(ilk); 966243900Sattilio panic("%s: downgrade a recursed lockmgr %s @ %s:%d\n", 967243900Sattilio __func__, iwmesg, file, line); 968243900Sattilio } 969178159Sattilio TD_SLOCKS_INC(curthread); 970177957Sattilio 97124269Speter /* 972177957Sattilio * In order to preserve waiters flags, just spin. 97324269Speter */ 974177957Sattilio for (;;) { 975194317Sattilio x = lk->lk_lock; 976194317Sattilio MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); 977194317Sattilio x &= LK_ALL_WAITERS; 978177957Sattilio if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid | x, 979178159Sattilio LK_SHARERS_LOCK(1) | x)) 980177957Sattilio break; 981177957Sattilio cpu_spinwait(); 98224269Speter } 98324269Speter break; 984177957Sattilio case LK_RELEASE: 985177957Sattilio _lockmgr_assert(lk, KA_LOCKED, file, line); 986177957Sattilio x = lk->lk_lock; 98724269Speter 988177957Sattilio if ((x & LK_SHARE) == 0) { 989177957Sattilio 990177957Sattilio /* 991177957Sattilio * As first option, treact the lock as if it has not 992177957Sattilio * any waiter. 993177957Sattilio * Fix-up the tid var if the lock has been disowned. 994177957Sattilio */ 995177957Sattilio if (LK_HOLDER(x) == LK_KERNPROC) 996177957Sattilio tid = LK_KERNPROC; 997178159Sattilio else { 998178159Sattilio WITNESS_UNLOCK(&lk->lock_object, LOP_EXCLUSIVE, 999178159Sattilio file, line); 1000177957Sattilio TD_LOCKS_DEC(curthread); 1001178159Sattilio } 1002177957Sattilio LOCK_LOG_LOCK("XUNLOCK", &lk->lock_object, 0, 1003177957Sattilio lk->lk_recurse, file, line); 1004177957Sattilio 1005177957Sattilio /* 1006177957Sattilio * The lock is held in exclusive mode. 1007177957Sattilio * If the lock is recursed also, then unrecurse it. 1008177957Sattilio */ 1009177957Sattilio if (lockmgr_xlocked(lk) && lockmgr_recursed(lk)) { 1010177957Sattilio LOCK_LOG2(lk, "%s: %p unrecursing", __func__, 1011177957Sattilio lk); 1012177957Sattilio lk->lk_recurse--; 1013177957Sattilio break; 1014176014Sattilio } 1015189788Sjeff if (tid != LK_KERNPROC) 1016189788Sjeff lock_profile_release_lock(&lk->lock_object); 1017177957Sattilio 1018177957Sattilio if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid, 1019177957Sattilio LK_UNLOCKED)) 1020177957Sattilio break; 1021177957Sattilio 1022177957Sattilio sleepq_lock(&lk->lock_object); 1023194317Sattilio x = lk->lk_lock; 1024177957Sattilio v = LK_UNLOCKED; 1025177957Sattilio 1026177957Sattilio /* 1027177957Sattilio * If the lock has exclusive waiters, give them 1028177957Sattilio * preference in order to avoid deadlock with 1029177957Sattilio * shared runners up. 1030200447Sattilio * If interruptible sleeps left the exclusive queue 1031200447Sattilio * empty avoid a starvation for the threads sleeping 1032200447Sattilio * on the shared queue by giving them precedence 1033200447Sattilio * and cleaning up the exclusive waiters bit anyway. 1034201709Sattilio * Please note that lk_exslpfail count may be lying 1035201709Sattilio * about the real number of waiters with the 1036201709Sattilio * LK_SLEEPFAIL flag on because they may be used in 1037201709Sattilio * conjuction with interruptible sleeps so 1038201710Sattilio * lk_exslpfail might be considered an 'upper limit' 1039201710Sattilio * bound, including the edge cases. 1040177957Sattilio */ 1041194317Sattilio MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); 1042200447Sattilio realexslp = sleepq_sleepcnt(&lk->lock_object, 1043200447Sattilio SQ_EXCLUSIVE_QUEUE); 1044200447Sattilio if ((x & LK_EXCLUSIVE_WAITERS) != 0 && realexslp != 0) { 1045200447Sattilio if (lk->lk_exslpfail < realexslp) { 1046200447Sattilio lk->lk_exslpfail = 0; 1047200447Sattilio queue = SQ_EXCLUSIVE_QUEUE; 1048200447Sattilio v |= (x & LK_SHARED_WAITERS); 1049200447Sattilio } else { 1050200447Sattilio lk->lk_exslpfail = 0; 1051200447Sattilio LOCK_LOG2(lk, 1052200447Sattilio "%s: %p has only LK_SLEEPFAIL sleepers", 1053200447Sattilio __func__, lk); 1054200447Sattilio LOCK_LOG2(lk, 1055200447Sattilio "%s: %p waking up threads on the exclusive queue", 1056200447Sattilio __func__, lk); 1057200447Sattilio wakeup_swapper = 1058200447Sattilio sleepq_broadcast(&lk->lock_object, 1059200447Sattilio SLEEPQ_LK, 0, SQ_EXCLUSIVE_QUEUE); 1060200447Sattilio queue = SQ_SHARED_QUEUE; 1061200447Sattilio } 1062177957Sattilio } else { 1063201703Sattilio 1064201703Sattilio /* 1065201703Sattilio * Exclusive waiters sleeping with LK_SLEEPFAIL 1066201703Sattilio * on and using interruptible sleeps/timeout 1067201703Sattilio * may have left spourious lk_exslpfail counts 1068201703Sattilio * on, so clean it up anyway. 1069201703Sattilio */ 1070201703Sattilio lk->lk_exslpfail = 0; 1071177957Sattilio queue = SQ_SHARED_QUEUE; 107224269Speter } 1073149723Sssouhlal 1074177957Sattilio LOCK_LOG3(lk, 1075177957Sattilio "%s: %p waking up threads on the %s queue", 1076177957Sattilio __func__, lk, queue == SQ_SHARED_QUEUE ? "shared" : 1077177957Sattilio "exclusive"); 1078177957Sattilio atomic_store_rel_ptr(&lk->lk_lock, v); 1079200447Sattilio wakeup_swapper |= sleepq_broadcast(&lk->lock_object, 1080181334Sjhb SLEEPQ_LK, 0, queue); 1081177957Sattilio sleepq_release(&lk->lock_object); 1082177957Sattilio break; 1083177957Sattilio } else 1084181334Sjhb wakeup_swapper = wakeupshlk(lk, file, line); 108524269Speter break; 1086177957Sattilio case LK_DRAIN: 1087178159Sattilio if (LK_CAN_WITNESS(flags)) 1088178159Sattilio WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER | 1089251326Sjhb LOP_EXCLUSIVE, file, line, flags & LK_INTERLOCK ? 1090251326Sjhb ilk : NULL); 109124269Speter 109224269Speter /* 1093180798Skib * Trying to drain a lock we already own will result in a 1094177957Sattilio * deadlock. 109524269Speter */ 1096177957Sattilio if (lockmgr_xlocked(lk)) { 1097177957Sattilio if (flags & LK_INTERLOCK) 1098177957Sattilio class->lc_unlock(ilk); 1099177957Sattilio panic("%s: draining %s with the lock held @ %s:%d\n", 1100177957Sattilio __func__, iwmesg, file, line); 1101177957Sattilio } 110228345Sdyson 1103177957Sattilio while (!atomic_cmpset_acq_ptr(&lk->lk_lock, LK_UNLOCKED, tid)) { 1104233628Sfabient#ifdef HWPMC_HOOKS 1105233628Sfabient PMC_SOFT_CALL( , , lock, failed); 1106233628Sfabient#endif 1107177957Sattilio lock_profile_obtain_lock_failed(&lk->lock_object, 1108177957Sattilio &contested, &waittime); 110924269Speter 1110177957Sattilio /* 1111177957Sattilio * If the lock is expected to not sleep just give up 1112177957Sattilio * and return. 1113177957Sattilio */ 1114177957Sattilio if (LK_TRYOP(flags)) { 1115177957Sattilio LOCK_LOG2(lk, "%s: %p fails the try operation", 1116177957Sattilio __func__, lk); 1117177957Sattilio error = EBUSY; 1118177957Sattilio break; 1119177957Sattilio } 112024269Speter 1121177957Sattilio /* 1122177957Sattilio * Acquire the sleepqueue chain lock because we 1123177957Sattilio * probabilly will need to manipulate waiters flags. 1124177957Sattilio */ 1125177957Sattilio sleepq_lock(&lk->lock_object); 1126177957Sattilio x = lk->lk_lock; 112729653Sdyson 1128177957Sattilio /* 1129177957Sattilio * if the lock has been released while we spun on 1130177957Sattilio * the sleepqueue chain lock just try again. 1131177957Sattilio */ 1132177957Sattilio if (x == LK_UNLOCKED) { 1133177957Sattilio sleepq_release(&lk->lock_object); 1134177957Sattilio continue; 1135177957Sattilio } 1136176320Sattilio 1137194317Sattilio v = x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); 1138194317Sattilio if ((x & ~v) == LK_UNLOCKED) { 1139194317Sattilio v = (x & ~LK_EXCLUSIVE_SPINNERS); 1140200447Sattilio 1141200447Sattilio /* 1142200447Sattilio * If interruptible sleeps left the exclusive 1143200447Sattilio * queue empty avoid a starvation for the 1144200447Sattilio * threads sleeping on the shared queue by 1145200447Sattilio * giving them precedence and cleaning up the 1146200447Sattilio * exclusive waiters bit anyway. 1147201709Sattilio * Please note that lk_exslpfail count may be 1148201709Sattilio * lying about the real number of waiters with 1149201709Sattilio * the LK_SLEEPFAIL flag on because they may 1150201709Sattilio * be used in conjuction with interruptible 1151201710Sattilio * sleeps so lk_exslpfail might be considered 1152201710Sattilio * an 'upper limit' bound, including the edge 1153201709Sattilio * cases. 1154200447Sattilio */ 1155177957Sattilio if (v & LK_EXCLUSIVE_WAITERS) { 1156177957Sattilio queue = SQ_EXCLUSIVE_QUEUE; 1157177957Sattilio v &= ~LK_EXCLUSIVE_WAITERS; 1158177957Sattilio } else { 1159201703Sattilio 1160201703Sattilio /* 1161201703Sattilio * Exclusive waiters sleeping with 1162201703Sattilio * LK_SLEEPFAIL on and using 1163201703Sattilio * interruptible sleeps/timeout may 1164201703Sattilio * have left spourious lk_exslpfail 1165201703Sattilio * counts on, so clean it up anyway. 1166201703Sattilio */ 1167177957Sattilio MPASS(v & LK_SHARED_WAITERS); 1168201703Sattilio lk->lk_exslpfail = 0; 1169177957Sattilio queue = SQ_SHARED_QUEUE; 1170177957Sattilio v &= ~LK_SHARED_WAITERS; 1171177957Sattilio } 1172200447Sattilio if (queue == SQ_EXCLUSIVE_QUEUE) { 1173200447Sattilio realexslp = 1174200447Sattilio sleepq_sleepcnt(&lk->lock_object, 1175200447Sattilio SQ_EXCLUSIVE_QUEUE); 1176200447Sattilio if (lk->lk_exslpfail >= realexslp) { 1177200447Sattilio lk->lk_exslpfail = 0; 1178200447Sattilio queue = SQ_SHARED_QUEUE; 1179200447Sattilio v &= ~LK_SHARED_WAITERS; 1180200447Sattilio if (realexslp != 0) { 1181200447Sattilio LOCK_LOG2(lk, 1182200447Sattilio "%s: %p has only LK_SLEEPFAIL sleepers", 1183200447Sattilio __func__, lk); 1184200447Sattilio LOCK_LOG2(lk, 1185200447Sattilio "%s: %p waking up threads on the exclusive queue", 1186200447Sattilio __func__, lk); 1187200447Sattilio wakeup_swapper = 1188200447Sattilio sleepq_broadcast( 1189200447Sattilio &lk->lock_object, 1190200447Sattilio SLEEPQ_LK, 0, 1191200447Sattilio SQ_EXCLUSIVE_QUEUE); 1192200447Sattilio } 1193200447Sattilio } else 1194200447Sattilio lk->lk_exslpfail = 0; 1195200447Sattilio } 1196177957Sattilio if (!atomic_cmpset_ptr(&lk->lk_lock, x, v)) { 1197177957Sattilio sleepq_release(&lk->lock_object); 1198177957Sattilio continue; 1199177957Sattilio } 1200177957Sattilio LOCK_LOG3(lk, 1201177957Sattilio "%s: %p waking up all threads on the %s queue", 1202177957Sattilio __func__, lk, queue == SQ_SHARED_QUEUE ? 1203177957Sattilio "shared" : "exclusive"); 1204182010Sjhb wakeup_swapper |= sleepq_broadcast( 1205181334Sjhb &lk->lock_object, SLEEPQ_LK, 0, queue); 1206177957Sattilio 1207177957Sattilio /* 1208177957Sattilio * If shared waiters have been woken up we need 1209177957Sattilio * to wait for one of them to acquire the lock 1210177957Sattilio * before to set the exclusive waiters in 1211177957Sattilio * order to avoid a deadlock. 1212177957Sattilio */ 1213177957Sattilio if (queue == SQ_SHARED_QUEUE) { 1214177957Sattilio for (v = lk->lk_lock; 1215177957Sattilio (v & LK_SHARE) && !LK_SHARERS(v); 1216177957Sattilio v = lk->lk_lock) 1217177957Sattilio cpu_spinwait(); 1218177957Sattilio } 1219177957Sattilio } 1220177957Sattilio 1221177957Sattilio /* 1222177957Sattilio * Try to set the LK_EXCLUSIVE_WAITERS flag. If we 1223177957Sattilio * fail, loop back and retry. 1224177957Sattilio */ 1225177957Sattilio if ((x & LK_EXCLUSIVE_WAITERS) == 0) { 1226177957Sattilio if (!atomic_cmpset_ptr(&lk->lk_lock, x, 1227177957Sattilio x | LK_EXCLUSIVE_WAITERS)) { 1228177957Sattilio sleepq_release(&lk->lock_object); 1229177957Sattilio continue; 1230177957Sattilio } 1231177957Sattilio LOCK_LOG2(lk, "%s: %p set drain waiters flag", 1232177957Sattilio __func__, lk); 1233177957Sattilio } 1234177957Sattilio 1235177957Sattilio /* 1236177957Sattilio * As far as we have been unable to acquire the 1237177957Sattilio * exclusive lock and the exclusive waiters flag 1238177957Sattilio * is set, we will sleep. 1239177957Sattilio */ 1240177957Sattilio if (flags & LK_INTERLOCK) { 1241177957Sattilio class->lc_unlock(ilk); 1242177957Sattilio flags &= ~LK_INTERLOCK; 1243177957Sattilio } 1244178159Sattilio GIANT_SAVE(); 1245177957Sattilio sleepq_add(&lk->lock_object, NULL, iwmesg, SLEEPQ_LK, 1246177957Sattilio SQ_EXCLUSIVE_QUEUE); 1247177957Sattilio sleepq_wait(&lk->lock_object, ipri & PRIMASK); 1248178159Sattilio GIANT_RESTORE(); 1249177957Sattilio LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", 1250177957Sattilio __func__, lk); 125129653Sdyson } 1252177957Sattilio 1253177957Sattilio if (error == 0) { 1254177957Sattilio lock_profile_obtain_lock_success(&lk->lock_object, 1255177957Sattilio contested, waittime, file, line); 1256177957Sattilio LOCK_LOG_LOCK("DRAIN", &lk->lock_object, 0, 1257177957Sattilio lk->lk_recurse, file, line); 1258178159Sattilio WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | 1259178159Sattilio LK_TRYWIT(flags), file, line); 1260177957Sattilio TD_LOCKS_INC(curthread); 1261177957Sattilio STACK_SAVE(lk); 1262177957Sattilio } 1263177957Sattilio break; 1264177957Sattilio default: 1265177957Sattilio if (flags & LK_INTERLOCK) 1266177957Sattilio class->lc_unlock(ilk); 1267177957Sattilio panic("%s: unknown lockmgr request 0x%x\n", __func__, op); 126829653Sdyson } 1269177957Sattilio 1270177957Sattilio if (flags & LK_INTERLOCK) 1271177957Sattilio class->lc_unlock(ilk); 1272181334Sjhb if (wakeup_swapper) 1273181334Sjhb kick_proc0(); 1274177957Sattilio 1275177957Sattilio return (error); 127629653Sdyson} 127729653Sdyson 127829653Sdysonvoid 1279177957Sattilio_lockmgr_disown(struct lock *lk, const char *file, int line) 128029653Sdyson{ 1281177957Sattilio uintptr_t tid, x; 1282176014Sattilio 1283228424Savg if (SCHEDULER_STOPPED()) 1284228424Savg return; 1285228424Savg 1286177957Sattilio tid = (uintptr_t)curthread; 1287243900Sattilio _lockmgr_assert(lk, KA_XLOCKED, file, line); 128829653Sdyson 1289177957Sattilio /* 1290243900Sattilio * Panic if the lock is recursed. 1291243900Sattilio */ 1292243900Sattilio if (lockmgr_xlocked(lk) && lockmgr_recursed(lk)) 1293243900Sattilio panic("%s: disown a recursed lockmgr @ %s:%d\n", 1294243900Sattilio __func__, file, line); 1295243900Sattilio 1296243900Sattilio /* 1297180798Skib * If the owner is already LK_KERNPROC just skip the whole operation. 1298177957Sattilio */ 1299177957Sattilio if (LK_HOLDER(lk->lk_lock) != tid) 1300177957Sattilio return; 1301189788Sjeff lock_profile_release_lock(&lk->lock_object); 1302178159Sattilio LOCK_LOG_LOCK("XDISOWN", &lk->lock_object, 0, 0, file, line); 1303178159Sattilio WITNESS_UNLOCK(&lk->lock_object, LOP_EXCLUSIVE, file, line); 1304178159Sattilio TD_LOCKS_DEC(curthread); 1305199008Sattilio STACK_SAVE(lk); 130629653Sdyson 1307177957Sattilio /* 1308177957Sattilio * In order to preserve waiters flags, just spin. 1309177957Sattilio */ 1310177957Sattilio for (;;) { 1311194317Sattilio x = lk->lk_lock; 1312194317Sattilio MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); 1313194317Sattilio x &= LK_ALL_WAITERS; 1314178166Sattilio if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid | x, 1315178159Sattilio LK_KERNPROC | x)) 1316177957Sattilio return; 1317177957Sattilio cpu_spinwait(); 1318177957Sattilio } 131966615Sjasone} 132066615Sjasone 1321175166Sattiliovoid 1322227588Spjdlockmgr_printinfo(const struct lock *lk) 1323175166Sattilio{ 1324175166Sattilio struct thread *td; 1325177957Sattilio uintptr_t x; 1326175166Sattilio 1327177957Sattilio if (lk->lk_lock == LK_UNLOCKED) 1328188244Sjhb printf("lock type %s: UNLOCKED\n", lk->lock_object.lo_name); 1329177957Sattilio else if (lk->lk_lock & LK_SHARE) 1330188244Sjhb printf("lock type %s: SHARED (count %ju)\n", 1331177957Sattilio lk->lock_object.lo_name, 1332177957Sattilio (uintmax_t)LK_SHARERS(lk->lk_lock)); 1333177957Sattilio else { 1334177957Sattilio td = lockmgr_xholder(lk); 1335232547Sivoras printf("lock type %s: EXCL by thread %p " 1336232547Sivoras "(pid %d, %s, tid %d)\n", lk->lock_object.lo_name, td, 1337232547Sivoras td->td_proc->p_pid, td->td_proc->p_comm, td->td_tid); 1338177957Sattilio } 1339175166Sattilio 1340177957Sattilio x = lk->lk_lock; 1341177957Sattilio if (x & LK_EXCLUSIVE_WAITERS) 1342177957Sattilio printf(" with exclusive waiters pending\n"); 1343177957Sattilio if (x & LK_SHARED_WAITERS) 1344177957Sattilio printf(" with shared waiters pending\n"); 1345194317Sattilio if (x & LK_EXCLUSIVE_SPINNERS) 1346194317Sattilio printf(" with exclusive spinners pending\n"); 1347177957Sattilio 1348177957Sattilio STACK_PRINT(lk); 1349175166Sattilio} 1350175166Sattilio 135129653Sdysonint 1352227588Spjdlockstatus(const struct lock *lk) 135329653Sdyson{ 1354177957Sattilio uintptr_t v, x; 1355177957Sattilio int ret; 135629653Sdyson 1357177957Sattilio ret = LK_SHARED; 1358177957Sattilio x = lk->lk_lock; 1359177957Sattilio v = LK_HOLDER(x); 1360175635Sattilio 1361177957Sattilio if ((x & LK_SHARE) == 0) { 1362177957Sattilio if (v == (uintptr_t)curthread || v == LK_KERNPROC) 1363177957Sattilio ret = LK_EXCLUSIVE; 136454444Seivind else 1365177957Sattilio ret = LK_EXCLOTHER; 1366177957Sattilio } else if (x == LK_UNLOCKED) 1367177957Sattilio ret = 0; 136829653Sdyson 1369177957Sattilio return (ret); 137024269Speter} 1371161322Sjhb 1372176249Sattilio#ifdef INVARIANT_SUPPORT 1373219028Snetchild 1374219028SnetchildFEATURE(invariant_support, 1375219028Snetchild "Support for modules compiled with INVARIANTS option"); 1376219028Snetchild 1377176249Sattilio#ifndef INVARIANTS 1378177957Sattilio#undef _lockmgr_assert 1379176249Sattilio#endif 1380176249Sattilio 1381176249Sattiliovoid 1382227588Spjd_lockmgr_assert(const struct lock *lk, int what, const char *file, int line) 1383176249Sattilio{ 1384176249Sattilio int slocked = 0; 1385176249Sattilio 1386176249Sattilio if (panicstr != NULL) 1387176249Sattilio return; 1388176249Sattilio switch (what) { 1389176249Sattilio case KA_SLOCKED: 1390176249Sattilio case KA_SLOCKED | KA_NOTRECURSED: 1391176249Sattilio case KA_SLOCKED | KA_RECURSED: 1392176249Sattilio slocked = 1; 1393176249Sattilio case KA_LOCKED: 1394176249Sattilio case KA_LOCKED | KA_NOTRECURSED: 1395176249Sattilio case KA_LOCKED | KA_RECURSED: 1396178159Sattilio#ifdef WITNESS 1397178159Sattilio 1398178159Sattilio /* 1399178159Sattilio * We cannot trust WITNESS if the lock is held in exclusive 1400178159Sattilio * mode and a call to lockmgr_disown() happened. 1401178159Sattilio * Workaround this skipping the check if the lock is held in 1402178159Sattilio * exclusive mode even for the KA_LOCKED case. 1403178159Sattilio */ 1404178159Sattilio if (slocked || (lk->lk_lock & LK_SHARE)) { 1405178159Sattilio witness_assert(&lk->lock_object, what, file, line); 1406178159Sattilio break; 1407178159Sattilio } 1408178159Sattilio#endif 1409177957Sattilio if (lk->lk_lock == LK_UNLOCKED || 1410177957Sattilio ((lk->lk_lock & LK_SHARE) == 0 && (slocked || 1411177957Sattilio (!lockmgr_xlocked(lk) && !lockmgr_disowned(lk))))) 1412176249Sattilio panic("Lock %s not %slocked @ %s:%d\n", 1413177957Sattilio lk->lock_object.lo_name, slocked ? "share" : "", 1414176249Sattilio file, line); 1415177957Sattilio 1416177957Sattilio if ((lk->lk_lock & LK_SHARE) == 0) { 1417177957Sattilio if (lockmgr_recursed(lk)) { 1418176249Sattilio if (what & KA_NOTRECURSED) 1419176249Sattilio panic("Lock %s recursed @ %s:%d\n", 1420177957Sattilio lk->lock_object.lo_name, file, 1421177957Sattilio line); 1422176249Sattilio } else if (what & KA_RECURSED) 1423176249Sattilio panic("Lock %s not recursed @ %s:%d\n", 1424177957Sattilio lk->lock_object.lo_name, file, line); 1425176249Sattilio } 1426176249Sattilio break; 1427176249Sattilio case KA_XLOCKED: 1428176249Sattilio case KA_XLOCKED | KA_NOTRECURSED: 1429176249Sattilio case KA_XLOCKED | KA_RECURSED: 1430177957Sattilio if (!lockmgr_xlocked(lk) && !lockmgr_disowned(lk)) 1431176249Sattilio panic("Lock %s not exclusively locked @ %s:%d\n", 1432177957Sattilio lk->lock_object.lo_name, file, line); 1433177957Sattilio if (lockmgr_recursed(lk)) { 1434176249Sattilio if (what & KA_NOTRECURSED) 1435176249Sattilio panic("Lock %s recursed @ %s:%d\n", 1436177957Sattilio lk->lock_object.lo_name, file, line); 1437176249Sattilio } else if (what & KA_RECURSED) 1438176249Sattilio panic("Lock %s not recursed @ %s:%d\n", 1439177957Sattilio lk->lock_object.lo_name, file, line); 1440176249Sattilio break; 1441176249Sattilio case KA_UNLOCKED: 1442177957Sattilio if (lockmgr_xlocked(lk) || lockmgr_disowned(lk)) 1443176249Sattilio panic("Lock %s exclusively locked @ %s:%d\n", 1444177957Sattilio lk->lock_object.lo_name, file, line); 1445176249Sattilio break; 1446176249Sattilio default: 1447177957Sattilio panic("Unknown lockmgr assertion: %d @ %s:%d\n", what, file, 1448177957Sattilio line); 1449176249Sattilio } 1450176249Sattilio} 1451177957Sattilio#endif 1452176249Sattilio 1453161322Sjhb#ifdef DDB 1454161337Sjhbint 1455161337Sjhblockmgr_chain(struct thread *td, struct thread **ownerp) 1456161337Sjhb{ 1457177957Sattilio struct lock *lk; 1458161337Sjhb 1459177957Sattilio lk = td->td_wchan; 1460161337Sjhb 1461177957Sattilio if (LOCK_CLASS(&lk->lock_object) != &lock_class_lockmgr) 1462177957Sattilio return (0); 1463177957Sattilio db_printf("blocked on lockmgr %s", lk->lock_object.lo_name); 1464177957Sattilio if (lk->lk_lock & LK_SHARE) 1465177957Sattilio db_printf("SHARED (count %ju)\n", 1466177957Sattilio (uintmax_t)LK_SHARERS(lk->lk_lock)); 1467177957Sattilio else 1468177957Sattilio db_printf("EXCL\n"); 1469177957Sattilio *ownerp = lockmgr_xholder(lk); 1470161337Sjhb 1471161337Sjhb return (1); 1472161337Sjhb} 1473161337Sjhb 1474177957Sattiliostatic void 1475227588Spjddb_show_lockmgr(const struct lock_object *lock) 1476161322Sjhb{ 1477161322Sjhb struct thread *td; 1478227588Spjd const struct lock *lk; 1479161322Sjhb 1480227588Spjd lk = (const struct lock *)lock; 1481161322Sjhb 1482168070Sjhb db_printf(" state: "); 1483177957Sattilio if (lk->lk_lock == LK_UNLOCKED) 1484161322Sjhb db_printf("UNLOCKED\n"); 1485177957Sattilio else if (lk->lk_lock & LK_SHARE) 1486177957Sattilio db_printf("SLOCK: %ju\n", (uintmax_t)LK_SHARERS(lk->lk_lock)); 1487177957Sattilio else { 1488177957Sattilio td = lockmgr_xholder(lk); 1489177957Sattilio if (td == (struct thread *)LK_KERNPROC) 1490177957Sattilio db_printf("XLOCK: LK_KERNPROC\n"); 1491177957Sattilio else 1492177957Sattilio db_printf("XLOCK: %p (tid %d, pid %d, \"%s\")\n", td, 1493177957Sattilio td->td_tid, td->td_proc->p_pid, 1494177957Sattilio td->td_proc->p_comm); 1495177957Sattilio if (lockmgr_recursed(lk)) 1496177957Sattilio db_printf(" recursed: %d\n", lk->lk_recurse); 1497177957Sattilio } 1498177957Sattilio db_printf(" waiters: "); 1499177957Sattilio switch (lk->lk_lock & LK_ALL_WAITERS) { 1500177957Sattilio case LK_SHARED_WAITERS: 1501177957Sattilio db_printf("shared\n"); 1502192022Strasz break; 1503177957Sattilio case LK_EXCLUSIVE_WAITERS: 1504177957Sattilio db_printf("exclusive\n"); 1505177957Sattilio break; 1506177957Sattilio case LK_ALL_WAITERS: 1507177957Sattilio db_printf("shared and exclusive\n"); 1508177957Sattilio break; 1509177957Sattilio default: 1510177957Sattilio db_printf("none\n"); 1511177957Sattilio } 1512194317Sattilio db_printf(" spinners: "); 1513194317Sattilio if (lk->lk_lock & LK_EXCLUSIVE_SPINNERS) 1514194317Sattilio db_printf("exclusive\n"); 1515194317Sattilio else 1516194317Sattilio db_printf("none\n"); 1517161322Sjhb} 1518161322Sjhb#endif 1519