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("$FreeBSD$"); 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 422271161Skiblockdisableshare(struct lock *lk) 423271161Skib{ 424271161Skib 425271161Skib lockmgr_assert(lk, KA_XLOCKED); 426271161Skib lk->lock_object.lo_flags |= LK_NOSHARE; 427271161Skib} 428271161Skib 429271161Skibvoid 430211531Sjhblockallowrecurse(struct lock *lk) 431211531Sjhb{ 432211531Sjhb 433211531Sjhb lockmgr_assert(lk, KA_XLOCKED); 434211531Sjhb lk->lock_object.lo_flags |= LO_RECURSABLE; 435211531Sjhb} 436211531Sjhb 437211531Sjhbvoid 438211531Sjhblockdisablerecurse(struct lock *lk) 439211531Sjhb{ 440211531Sjhb 441211531Sjhb lockmgr_assert(lk, KA_XLOCKED); 442211531Sjhb lk->lock_object.lo_flags &= ~LO_RECURSABLE; 443211531Sjhb} 444211531Sjhb 445211531Sjhbvoid 446177957Sattiliolockdestroy(struct lock *lk) 447177957Sattilio{ 44842453Seivind 449177957Sattilio KASSERT(lk->lk_lock == LK_UNLOCKED, ("lockmgr still held")); 450177957Sattilio KASSERT(lk->lk_recurse == 0, ("lockmgr still recursed")); 451200447Sattilio KASSERT(lk->lk_exslpfail == 0, ("lockmgr still exclusive waiters")); 452177957Sattilio lock_destroy(&lk->lock_object); 45328345Sdyson} 45428345Sdyson 455177957Sattilioint 456177957Sattilio__lockmgr_args(struct lock *lk, u_int flags, struct lock_object *ilk, 457177957Sattilio const char *wmesg, int pri, int timo, const char *file, int line) 458140711Sjeff{ 459178159Sattilio GIANT_DECLARE; 460177957Sattilio struct lock_class *class; 461176320Sattilio const char *iwmesg; 462177957Sattilio uintptr_t tid, v, x; 463200447Sattilio u_int op, realexslp; 464189846Sjeff int error, ipri, itimo, queue, wakeup_swapper; 465189846Sjeff#ifdef LOCK_PROFILING 466189846Sjeff uint64_t waittime = 0; 467189846Sjeff int contested = 0; 468189846Sjeff#endif 469194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 470194317Sattilio volatile struct thread *owner; 471194317Sattilio u_int i, spintries = 0; 472194317Sattilio#endif 473176320Sattilio 474177957Sattilio error = 0; 475177957Sattilio tid = (uintptr_t)curthread; 476177957Sattilio op = (flags & LK_TYPE_MASK); 477177957Sattilio iwmesg = (wmesg == LK_WMESG_DEFAULT) ? lk->lock_object.lo_name : wmesg; 478177957Sattilio ipri = (pri == LK_PRIO_DEFAULT) ? lk->lk_pri : pri; 479177957Sattilio itimo = (timo == LK_TIMO_DEFAULT) ? lk->lk_timo : timo; 480176320Sattilio 481177957Sattilio MPASS((flags & ~LK_TOTAL_MASK) == 0); 482178150Sattilio KASSERT((op & (op - 1)) == 0, 483178150Sattilio ("%s: Invalid requested operation @ %s:%d", __func__, file, line)); 484177957Sattilio KASSERT((flags & (LK_NOWAIT | LK_SLEEPFAIL)) == 0 || 485177957Sattilio (op != LK_DOWNGRADE && op != LK_RELEASE), 486177957Sattilio ("%s: Invalid flags in regard of the operation desired @ %s:%d", 487177957Sattilio __func__, file, line)); 488177957Sattilio KASSERT((flags & LK_INTERLOCK) == 0 || ilk != NULL, 489177957Sattilio ("%s: LK_INTERLOCK passed without valid interlock @ %s:%d", 490177957Sattilio __func__, file, line)); 491244582Sattilio KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread), 492240424Sattilio ("%s: idle thread %p on lockmgr %s @ %s:%d", __func__, curthread, 493240424Sattilio lk->lock_object.lo_name, file, line)); 49466615Sjasone 495177957Sattilio class = (flags & LK_INTERLOCK) ? LOCK_CLASS(ilk) : NULL; 496177957Sattilio if (panicstr != NULL) { 497177957Sattilio if (flags & LK_INTERLOCK) 498177957Sattilio class->lc_unlock(ilk); 499177957Sattilio return (0); 50028345Sdyson } 50128345Sdyson 502224581Skib if (lk->lock_object.lo_flags & LK_NOSHARE) { 503224581Skib switch (op) { 504224581Skib case LK_SHARED: 505224581Skib op = LK_EXCLUSIVE; 506224581Skib break; 507224581Skib case LK_UPGRADE: 508255940Skib case LK_TRYUPGRADE: 509224581Skib case LK_DOWNGRADE: 510224581Skib _lockmgr_assert(lk, KA_XLOCKED | KA_NOTRECURSED, 511224581Skib file, line); 512245113Smjg if (flags & LK_INTERLOCK) 513245113Smjg class->lc_unlock(ilk); 514224581Skib return (0); 515224581Skib } 516224581Skib } 517164159Skmacy 518181334Sjhb wakeup_swapper = 0; 519177957Sattilio switch (op) { 520177957Sattilio case LK_SHARED: 521178159Sattilio if (LK_CAN_WITNESS(flags)) 522178159Sattilio WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER, 523251326Sjhb file, line, flags & LK_INTERLOCK ? ilk : NULL); 524177957Sattilio for (;;) { 525177957Sattilio x = lk->lk_lock; 526174948Sattilio 527177957Sattilio /* 528177957Sattilio * If no other thread has an exclusive lock, or 529177957Sattilio * no exclusive waiter is present, bump the count of 530177957Sattilio * sharers. Since we have to preserve the state of 531177957Sattilio * waiters, if we fail to acquire the shared lock 532177957Sattilio * loop back and retry. 533177957Sattilio */ 534177957Sattilio if (LK_CAN_SHARE(x)) { 535177957Sattilio if (atomic_cmpset_acq_ptr(&lk->lk_lock, x, 536177957Sattilio x + LK_ONE_SHARER)) 537177957Sattilio break; 538177957Sattilio continue; 539177957Sattilio } 540233628Sfabient#ifdef HWPMC_HOOKS 541233628Sfabient PMC_SOFT_CALL( , , lock, failed); 542233628Sfabient#endif 543177957Sattilio lock_profile_obtain_lock_failed(&lk->lock_object, 544177957Sattilio &contested, &waittime); 54528345Sdyson 546177957Sattilio /* 547180798Skib * If the lock is already held by curthread in 548177957Sattilio * exclusive way avoid a deadlock. 549177957Sattilio */ 550177957Sattilio if (LK_HOLDER(x) == tid) { 551177957Sattilio LOCK_LOG2(lk, 552180798Skib "%s: %p already held in exclusive mode", 553177957Sattilio __func__, lk); 554177957Sattilio error = EDEADLK; 555177957Sattilio break; 556177957Sattilio } 557140711Sjeff 558177957Sattilio /* 559177957Sattilio * If the lock is expected to not sleep just give up 560177957Sattilio * and return. 561177957Sattilio */ 562177957Sattilio if (LK_TRYOP(flags)) { 563177957Sattilio LOCK_LOG2(lk, "%s: %p fails the try operation", 564177957Sattilio __func__, lk); 565177957Sattilio error = EBUSY; 566177957Sattilio break; 567177957Sattilio } 56828345Sdyson 569194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 570177957Sattilio /* 571194317Sattilio * If the owner is running on another CPU, spin until 572194317Sattilio * the owner stops running or the state of the lock 573196772Sattilio * changes. We need a double-state handle here 574196772Sattilio * because for a failed acquisition the lock can be 575196772Sattilio * either held in exclusive mode or shared mode 576196772Sattilio * (for the writer starvation avoidance technique). 577194317Sattilio */ 578194317Sattilio if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 579194317Sattilio LK_HOLDER(x) != LK_KERNPROC) { 580194317Sattilio owner = (struct thread *)LK_HOLDER(x); 581194317Sattilio if (LOCK_LOG_TEST(&lk->lock_object, 0)) 582194317Sattilio CTR3(KTR_LOCK, 583194317Sattilio "%s: spinning on %p held by %p", 584194317Sattilio __func__, lk, owner); 585194317Sattilio 586194317Sattilio /* 587194317Sattilio * If we are holding also an interlock drop it 588194317Sattilio * in order to avoid a deadlock if the lockmgr 589194317Sattilio * owner is adaptively spinning on the 590194317Sattilio * interlock itself. 591194317Sattilio */ 592194317Sattilio if (flags & LK_INTERLOCK) { 593194317Sattilio class->lc_unlock(ilk); 594194317Sattilio flags &= ~LK_INTERLOCK; 595194317Sattilio } 596194317Sattilio GIANT_SAVE(); 597194317Sattilio while (LK_HOLDER(lk->lk_lock) == 598194317Sattilio (uintptr_t)owner && TD_IS_RUNNING(owner)) 599194317Sattilio cpu_spinwait(); 600196772Sattilio GIANT_RESTORE(); 601196772Sattilio continue; 602194317Sattilio } else if (LK_CAN_ADAPT(lk, flags) && 603196772Sattilio (x & LK_SHARE) != 0 && LK_SHARERS(x) && 604194317Sattilio spintries < alk_retries) { 605194317Sattilio if (flags & LK_INTERLOCK) { 606194317Sattilio class->lc_unlock(ilk); 607194317Sattilio flags &= ~LK_INTERLOCK; 608194317Sattilio } 609194317Sattilio GIANT_SAVE(); 610194317Sattilio spintries++; 611194317Sattilio for (i = 0; i < alk_loops; i++) { 612194317Sattilio if (LOCK_LOG_TEST(&lk->lock_object, 0)) 613194317Sattilio CTR4(KTR_LOCK, 614194317Sattilio "%s: shared spinning on %p with %u and %u", 615194317Sattilio __func__, lk, spintries, i); 616194317Sattilio x = lk->lk_lock; 617194317Sattilio if ((x & LK_SHARE) == 0 || 618194317Sattilio LK_CAN_SHARE(x) != 0) 619194317Sattilio break; 620194317Sattilio cpu_spinwait(); 621194317Sattilio } 622196772Sattilio GIANT_RESTORE(); 623194317Sattilio if (i != alk_loops) 624194317Sattilio continue; 625194317Sattilio } 626194317Sattilio#endif 627194317Sattilio 628194317Sattilio /* 629177957Sattilio * Acquire the sleepqueue chain lock because we 630177957Sattilio * probabilly will need to manipulate waiters flags. 631177957Sattilio */ 632177957Sattilio sleepq_lock(&lk->lock_object); 633177957Sattilio x = lk->lk_lock; 634111463Sjeff 635177957Sattilio /* 636177957Sattilio * if the lock can be acquired in shared mode, try 637177957Sattilio * again. 638177957Sattilio */ 639177957Sattilio if (LK_CAN_SHARE(x)) { 640177957Sattilio sleepq_release(&lk->lock_object); 641177957Sattilio continue; 642177957Sattilio } 64324269Speter 644194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 645177957Sattilio /* 646194317Sattilio * The current lock owner might have started executing 647194317Sattilio * on another CPU (or the lock could have changed 648194317Sattilio * owner) while we were waiting on the turnstile 649194317Sattilio * chain lock. If so, drop the turnstile lock and try 650194317Sattilio * again. 651194317Sattilio */ 652194317Sattilio if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 653194317Sattilio LK_HOLDER(x) != LK_KERNPROC) { 654194317Sattilio owner = (struct thread *)LK_HOLDER(x); 655194317Sattilio if (TD_IS_RUNNING(owner)) { 656194317Sattilio sleepq_release(&lk->lock_object); 657194317Sattilio continue; 658194317Sattilio } 659194317Sattilio } 660194317Sattilio#endif 661194317Sattilio 662194317Sattilio /* 663177957Sattilio * Try to set the LK_SHARED_WAITERS flag. If we fail, 664177957Sattilio * loop back and retry. 665177957Sattilio */ 666177957Sattilio if ((x & LK_SHARED_WAITERS) == 0) { 667177957Sattilio if (!atomic_cmpset_acq_ptr(&lk->lk_lock, x, 668177957Sattilio x | LK_SHARED_WAITERS)) { 669177957Sattilio sleepq_release(&lk->lock_object); 670177957Sattilio continue; 671177957Sattilio } 672177957Sattilio LOCK_LOG2(lk, "%s: %p set shared waiters flag", 673177957Sattilio __func__, lk); 674177957Sattilio } 67524269Speter 676177957Sattilio /* 677177957Sattilio * As far as we have been unable to acquire the 678177957Sattilio * shared lock and the shared waiters flag is set, 679177957Sattilio * we will sleep. 680177957Sattilio */ 681177957Sattilio error = sleeplk(lk, flags, ilk, iwmesg, ipri, itimo, 682177957Sattilio SQ_SHARED_QUEUE); 683177957Sattilio flags &= ~LK_INTERLOCK; 684177957Sattilio if (error) { 685177957Sattilio LOCK_LOG3(lk, 686177957Sattilio "%s: interrupted sleep for %p with %d", 687177957Sattilio __func__, lk, error); 688177957Sattilio break; 689177957Sattilio } 690177957Sattilio LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", 691177957Sattilio __func__, lk); 692177957Sattilio } 693177957Sattilio if (error == 0) { 694177957Sattilio lock_profile_obtain_lock_success(&lk->lock_object, 695177957Sattilio contested, waittime, file, line); 696177957Sattilio LOCK_LOG_LOCK("SLOCK", &lk->lock_object, 0, 0, file, 697176014Sattilio line); 698178159Sattilio WITNESS_LOCK(&lk->lock_object, LK_TRYWIT(flags), file, 699178159Sattilio line); 700177957Sattilio TD_LOCKS_INC(curthread); 701177957Sattilio TD_SLOCKS_INC(curthread); 702177957Sattilio STACK_SAVE(lk); 703177957Sattilio } 704177957Sattilio break; 705177957Sattilio case LK_UPGRADE: 706255940Skib case LK_TRYUPGRADE: 707177957Sattilio _lockmgr_assert(lk, KA_SLOCKED, file, line); 708194317Sattilio v = lk->lk_lock; 709194317Sattilio x = v & LK_ALL_WAITERS; 710194317Sattilio v &= LK_EXCLUSIVE_SPINNERS; 711177957Sattilio 71244681Sjulian /* 713177957Sattilio * Try to switch from one shared lock to an exclusive one. 714177957Sattilio * We need to preserve waiters flags during the operation. 71544681Sjulian */ 716194317Sattilio if (atomic_cmpset_ptr(&lk->lk_lock, LK_SHARERS_LOCK(1) | x | v, 717177957Sattilio tid | x)) { 718177957Sattilio LOCK_LOG_LOCK("XUPGRADE", &lk->lock_object, 0, 0, file, 719177957Sattilio line); 720178159Sattilio WITNESS_UPGRADE(&lk->lock_object, LOP_EXCLUSIVE | 721178159Sattilio LK_TRYWIT(flags), file, line); 722177957Sattilio TD_SLOCKS_DEC(curthread); 72324269Speter break; 72424269Speter } 725177957Sattilio 72624269Speter /* 727255940Skib * In LK_TRYUPGRADE mode, do not drop the lock, 728255940Skib * returning EBUSY instead. 729255940Skib */ 730255940Skib if (op == LK_TRYUPGRADE) { 731255940Skib LOCK_LOG2(lk, "%s: %p failed the nowait upgrade", 732255940Skib __func__, lk); 733255940Skib error = EBUSY; 734255940Skib break; 735255940Skib } 736255940Skib 737255940Skib /* 738177957Sattilio * We have been unable to succeed in upgrading, so just 739177957Sattilio * give up the shared lock. 74024269Speter */ 741182010Sjhb wakeup_swapper |= wakeupshlk(lk, file, line); 74224269Speter 743177957Sattilio /* FALLTHROUGH */ 744177957Sattilio case LK_EXCLUSIVE: 745178159Sattilio if (LK_CAN_WITNESS(flags)) 746178159Sattilio WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER | 747251326Sjhb LOP_EXCLUSIVE, file, line, flags & LK_INTERLOCK ? 748251326Sjhb ilk : NULL); 74924269Speter 75024269Speter /* 751180798Skib * If curthread already holds the lock and this one is 752177957Sattilio * allowed to recurse, simply recurse on it. 75324269Speter */ 754177957Sattilio if (lockmgr_xlocked(lk)) { 755177957Sattilio if ((flags & LK_CANRECURSE) == 0 && 756193307Sattilio (lk->lock_object.lo_flags & LO_RECURSABLE) == 0) { 757177957Sattilio 758177957Sattilio /* 759177957Sattilio * If the lock is expected to not panic just 760177957Sattilio * give up and return. 761177957Sattilio */ 762177957Sattilio if (LK_TRYOP(flags)) { 763177957Sattilio LOCK_LOG2(lk, 764177957Sattilio "%s: %p fails the try operation", 765177957Sattilio __func__, lk); 766177957Sattilio error = EBUSY; 767177957Sattilio break; 768177957Sattilio } 769177957Sattilio if (flags & LK_INTERLOCK) 770177957Sattilio class->lc_unlock(ilk); 771177957Sattilio panic("%s: recursing on non recursive lockmgr %s @ %s:%d\n", 772177957Sattilio __func__, iwmesg, file, line); 773177957Sattilio } 774177957Sattilio lk->lk_recurse++; 775177957Sattilio LOCK_LOG2(lk, "%s: %p recursing", __func__, lk); 776177957Sattilio LOCK_LOG_LOCK("XLOCK", &lk->lock_object, 0, 777177957Sattilio lk->lk_recurse, file, line); 778178159Sattilio WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | 779178159Sattilio LK_TRYWIT(flags), file, line); 780177957Sattilio TD_LOCKS_INC(curthread); 78124269Speter break; 78224269Speter } 783177957Sattilio 784177957Sattilio while (!atomic_cmpset_acq_ptr(&lk->lk_lock, LK_UNLOCKED, 785177957Sattilio tid)) { 786233628Sfabient#ifdef HWPMC_HOOKS 787233628Sfabient PMC_SOFT_CALL( , , lock, failed); 788233628Sfabient#endif 789177957Sattilio lock_profile_obtain_lock_failed(&lk->lock_object, 790177957Sattilio &contested, &waittime); 791177957Sattilio 79224269Speter /* 793177957Sattilio * If the lock is expected to not sleep just give up 794177957Sattilio * and return. 79524269Speter */ 796177957Sattilio if (LK_TRYOP(flags)) { 797177957Sattilio LOCK_LOG2(lk, "%s: %p fails the try operation", 798177957Sattilio __func__, lk); 799177957Sattilio error = EBUSY; 800177957Sattilio break; 801177957Sattilio } 80234194Sdyson 803194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 804177957Sattilio /* 805194317Sattilio * If the owner is running on another CPU, spin until 806194317Sattilio * the owner stops running or the state of the lock 807194317Sattilio * changes. 808194317Sattilio */ 809194317Sattilio x = lk->lk_lock; 810194317Sattilio if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 811194317Sattilio LK_HOLDER(x) != LK_KERNPROC) { 812194317Sattilio owner = (struct thread *)LK_HOLDER(x); 813194317Sattilio if (LOCK_LOG_TEST(&lk->lock_object, 0)) 814194317Sattilio CTR3(KTR_LOCK, 815194317Sattilio "%s: spinning on %p held by %p", 816194317Sattilio __func__, lk, owner); 817194317Sattilio 818194317Sattilio /* 819194317Sattilio * If we are holding also an interlock drop it 820194317Sattilio * in order to avoid a deadlock if the lockmgr 821194317Sattilio * owner is adaptively spinning on the 822194317Sattilio * interlock itself. 823194317Sattilio */ 824194317Sattilio if (flags & LK_INTERLOCK) { 825194317Sattilio class->lc_unlock(ilk); 826194317Sattilio flags &= ~LK_INTERLOCK; 827194317Sattilio } 828194317Sattilio GIANT_SAVE(); 829194317Sattilio while (LK_HOLDER(lk->lk_lock) == 830194317Sattilio (uintptr_t)owner && TD_IS_RUNNING(owner)) 831194317Sattilio cpu_spinwait(); 832196772Sattilio GIANT_RESTORE(); 833196772Sattilio continue; 834194317Sattilio } else if (LK_CAN_ADAPT(lk, flags) && 835194317Sattilio (x & LK_SHARE) != 0 && LK_SHARERS(x) && 836194317Sattilio spintries < alk_retries) { 837194317Sattilio if ((x & LK_EXCLUSIVE_SPINNERS) == 0 && 838194317Sattilio !atomic_cmpset_ptr(&lk->lk_lock, x, 839194317Sattilio x | LK_EXCLUSIVE_SPINNERS)) 840194317Sattilio continue; 841194317Sattilio if (flags & LK_INTERLOCK) { 842194317Sattilio class->lc_unlock(ilk); 843194317Sattilio flags &= ~LK_INTERLOCK; 844194317Sattilio } 845194317Sattilio GIANT_SAVE(); 846194317Sattilio spintries++; 847194317Sattilio for (i = 0; i < alk_loops; i++) { 848194317Sattilio if (LOCK_LOG_TEST(&lk->lock_object, 0)) 849194317Sattilio CTR4(KTR_LOCK, 850194317Sattilio "%s: shared spinning on %p with %u and %u", 851194317Sattilio __func__, lk, spintries, i); 852194317Sattilio if ((lk->lk_lock & 853194317Sattilio LK_EXCLUSIVE_SPINNERS) == 0) 854194317Sattilio break; 855194317Sattilio cpu_spinwait(); 856194317Sattilio } 857196772Sattilio GIANT_RESTORE(); 858194317Sattilio if (i != alk_loops) 859194317Sattilio continue; 860194317Sattilio } 861194317Sattilio#endif 862194317Sattilio 863194317Sattilio /* 864177957Sattilio * Acquire the sleepqueue chain lock because we 865177957Sattilio * probabilly will need to manipulate waiters flags. 866177957Sattilio */ 867177957Sattilio sleepq_lock(&lk->lock_object); 868177957Sattilio x = lk->lk_lock; 869177957Sattilio 870177957Sattilio /* 871177957Sattilio * if the lock has been released while we spun on 872177957Sattilio * the sleepqueue chain lock just try again. 873177957Sattilio */ 874177957Sattilio if (x == LK_UNLOCKED) { 875177957Sattilio sleepq_release(&lk->lock_object); 876177957Sattilio continue; 877134365Skan } 87824269Speter 879194317Sattilio#ifdef ADAPTIVE_LOCKMGRS 88024269Speter /* 881194317Sattilio * The current lock owner might have started executing 882194317Sattilio * on another CPU (or the lock could have changed 883194317Sattilio * owner) while we were waiting on the turnstile 884194317Sattilio * chain lock. If so, drop the turnstile lock and try 885194317Sattilio * again. 886194317Sattilio */ 887194317Sattilio if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 888194317Sattilio LK_HOLDER(x) != LK_KERNPROC) { 889194317Sattilio owner = (struct thread *)LK_HOLDER(x); 890194317Sattilio if (TD_IS_RUNNING(owner)) { 891194317Sattilio sleepq_release(&lk->lock_object); 892194317Sattilio continue; 893194317Sattilio } 894194317Sattilio } 895194317Sattilio#endif 896194317Sattilio 897194317Sattilio /* 898177957Sattilio * The lock can be in the state where there is a 899177957Sattilio * pending queue of waiters, but still no owner. 900177957Sattilio * This happens when the lock is contested and an 901177957Sattilio * owner is going to claim the lock. 902177957Sattilio * If curthread is the one successfully acquiring it 903177957Sattilio * claim lock ownership and return, preserving waiters 904177957Sattilio * flags. 90524269Speter */ 906194317Sattilio v = x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); 907194317Sattilio if ((x & ~v) == LK_UNLOCKED) { 908194317Sattilio v &= ~LK_EXCLUSIVE_SPINNERS; 909177957Sattilio if (atomic_cmpset_acq_ptr(&lk->lk_lock, x, 910177957Sattilio tid | v)) { 911177957Sattilio sleepq_release(&lk->lock_object); 912177957Sattilio LOCK_LOG2(lk, 913177957Sattilio "%s: %p claimed by a new writer", 914177957Sattilio __func__, lk); 915177957Sattilio break; 916177957Sattilio } 917177957Sattilio sleepq_release(&lk->lock_object); 918177957Sattilio continue; 919177957Sattilio } 920177957Sattilio 921177957Sattilio /* 922177957Sattilio * Try to set the LK_EXCLUSIVE_WAITERS flag. If we 923177957Sattilio * fail, loop back and retry. 924177957Sattilio */ 925177957Sattilio if ((x & LK_EXCLUSIVE_WAITERS) == 0) { 926177957Sattilio if (!atomic_cmpset_ptr(&lk->lk_lock, x, 927177957Sattilio x | LK_EXCLUSIVE_WAITERS)) { 928177957Sattilio sleepq_release(&lk->lock_object); 929177957Sattilio continue; 930177957Sattilio } 931177957Sattilio LOCK_LOG2(lk, "%s: %p set excl waiters flag", 932177957Sattilio __func__, lk); 933177957Sattilio } 934177957Sattilio 935177957Sattilio /* 936177957Sattilio * As far as we have been unable to acquire the 937177957Sattilio * exclusive lock and the exclusive waiters flag 938177957Sattilio * is set, we will sleep. 939177957Sattilio */ 940177957Sattilio error = sleeplk(lk, flags, ilk, iwmesg, ipri, itimo, 941177957Sattilio SQ_EXCLUSIVE_QUEUE); 942177957Sattilio flags &= ~LK_INTERLOCK; 943177957Sattilio if (error) { 944177957Sattilio LOCK_LOG3(lk, 945177957Sattilio "%s: interrupted sleep for %p with %d", 946177957Sattilio __func__, lk, error); 94748301Smckusick break; 94848301Smckusick } 949177957Sattilio LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", 950177957Sattilio __func__, lk); 95124269Speter } 952177957Sattilio if (error == 0) { 953177957Sattilio lock_profile_obtain_lock_success(&lk->lock_object, 954177957Sattilio contested, waittime, file, line); 955177957Sattilio LOCK_LOG_LOCK("XLOCK", &lk->lock_object, 0, 956177957Sattilio lk->lk_recurse, file, line); 957178159Sattilio WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | 958178159Sattilio LK_TRYWIT(flags), file, line); 959177957Sattilio TD_LOCKS_INC(curthread); 960177957Sattilio STACK_SAVE(lk); 961177957Sattilio } 962177957Sattilio break; 963177957Sattilio case LK_DOWNGRADE: 964243900Sattilio _lockmgr_assert(lk, KA_XLOCKED, file, line); 965178159Sattilio LOCK_LOG_LOCK("XDOWNGRADE", &lk->lock_object, 0, 0, file, line); 966178159Sattilio WITNESS_DOWNGRADE(&lk->lock_object, 0, file, line); 967243900Sattilio 968243900Sattilio /* 969243900Sattilio * Panic if the lock is recursed. 970243900Sattilio */ 971243900Sattilio if (lockmgr_xlocked(lk) && lockmgr_recursed(lk)) { 972243900Sattilio if (flags & LK_INTERLOCK) 973243900Sattilio class->lc_unlock(ilk); 974243900Sattilio panic("%s: downgrade a recursed lockmgr %s @ %s:%d\n", 975243900Sattilio __func__, iwmesg, file, line); 976243900Sattilio } 977178159Sattilio TD_SLOCKS_INC(curthread); 978177957Sattilio 97924269Speter /* 980177957Sattilio * In order to preserve waiters flags, just spin. 98124269Speter */ 982177957Sattilio for (;;) { 983194317Sattilio x = lk->lk_lock; 984194317Sattilio MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); 985194317Sattilio x &= LK_ALL_WAITERS; 986177957Sattilio if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid | x, 987178159Sattilio LK_SHARERS_LOCK(1) | x)) 988177957Sattilio break; 989177957Sattilio cpu_spinwait(); 99024269Speter } 99124269Speter break; 992177957Sattilio case LK_RELEASE: 993177957Sattilio _lockmgr_assert(lk, KA_LOCKED, file, line); 994177957Sattilio x = lk->lk_lock; 99524269Speter 996177957Sattilio if ((x & LK_SHARE) == 0) { 997177957Sattilio 998177957Sattilio /* 999177957Sattilio * As first option, treact the lock as if it has not 1000177957Sattilio * any waiter. 1001177957Sattilio * Fix-up the tid var if the lock has been disowned. 1002177957Sattilio */ 1003177957Sattilio if (LK_HOLDER(x) == LK_KERNPROC) 1004177957Sattilio tid = LK_KERNPROC; 1005178159Sattilio else { 1006178159Sattilio WITNESS_UNLOCK(&lk->lock_object, LOP_EXCLUSIVE, 1007178159Sattilio file, line); 1008177957Sattilio TD_LOCKS_DEC(curthread); 1009178159Sattilio } 1010177957Sattilio LOCK_LOG_LOCK("XUNLOCK", &lk->lock_object, 0, 1011177957Sattilio lk->lk_recurse, file, line); 1012177957Sattilio 1013177957Sattilio /* 1014177957Sattilio * The lock is held in exclusive mode. 1015177957Sattilio * If the lock is recursed also, then unrecurse it. 1016177957Sattilio */ 1017177957Sattilio if (lockmgr_xlocked(lk) && lockmgr_recursed(lk)) { 1018177957Sattilio LOCK_LOG2(lk, "%s: %p unrecursing", __func__, 1019177957Sattilio lk); 1020177957Sattilio lk->lk_recurse--; 1021177957Sattilio break; 1022176014Sattilio } 1023189788Sjeff if (tid != LK_KERNPROC) 1024189788Sjeff lock_profile_release_lock(&lk->lock_object); 1025177957Sattilio 1026177957Sattilio if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid, 1027177957Sattilio LK_UNLOCKED)) 1028177957Sattilio break; 1029177957Sattilio 1030177957Sattilio sleepq_lock(&lk->lock_object); 1031194317Sattilio x = lk->lk_lock; 1032177957Sattilio v = LK_UNLOCKED; 1033177957Sattilio 1034177957Sattilio /* 1035177957Sattilio * If the lock has exclusive waiters, give them 1036177957Sattilio * preference in order to avoid deadlock with 1037177957Sattilio * shared runners up. 1038200447Sattilio * If interruptible sleeps left the exclusive queue 1039200447Sattilio * empty avoid a starvation for the threads sleeping 1040200447Sattilio * on the shared queue by giving them precedence 1041200447Sattilio * and cleaning up the exclusive waiters bit anyway. 1042201709Sattilio * Please note that lk_exslpfail count may be lying 1043201709Sattilio * about the real number of waiters with the 1044201709Sattilio * LK_SLEEPFAIL flag on because they may be used in 1045201709Sattilio * conjuction with interruptible sleeps so 1046201710Sattilio * lk_exslpfail might be considered an 'upper limit' 1047201710Sattilio * bound, including the edge cases. 1048177957Sattilio */ 1049194317Sattilio MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); 1050200447Sattilio realexslp = sleepq_sleepcnt(&lk->lock_object, 1051200447Sattilio SQ_EXCLUSIVE_QUEUE); 1052200447Sattilio if ((x & LK_EXCLUSIVE_WAITERS) != 0 && realexslp != 0) { 1053200447Sattilio if (lk->lk_exslpfail < realexslp) { 1054200447Sattilio lk->lk_exslpfail = 0; 1055200447Sattilio queue = SQ_EXCLUSIVE_QUEUE; 1056200447Sattilio v |= (x & LK_SHARED_WAITERS); 1057200447Sattilio } else { 1058200447Sattilio lk->lk_exslpfail = 0; 1059200447Sattilio LOCK_LOG2(lk, 1060200447Sattilio "%s: %p has only LK_SLEEPFAIL sleepers", 1061200447Sattilio __func__, lk); 1062200447Sattilio LOCK_LOG2(lk, 1063200447Sattilio "%s: %p waking up threads on the exclusive queue", 1064200447Sattilio __func__, lk); 1065200447Sattilio wakeup_swapper = 1066200447Sattilio sleepq_broadcast(&lk->lock_object, 1067200447Sattilio SLEEPQ_LK, 0, SQ_EXCLUSIVE_QUEUE); 1068200447Sattilio queue = SQ_SHARED_QUEUE; 1069200447Sattilio } 1070177957Sattilio } else { 1071201703Sattilio 1072201703Sattilio /* 1073201703Sattilio * Exclusive waiters sleeping with LK_SLEEPFAIL 1074201703Sattilio * on and using interruptible sleeps/timeout 1075201703Sattilio * may have left spourious lk_exslpfail counts 1076201703Sattilio * on, so clean it up anyway. 1077201703Sattilio */ 1078201703Sattilio lk->lk_exslpfail = 0; 1079177957Sattilio queue = SQ_SHARED_QUEUE; 108024269Speter } 1081149723Sssouhlal 1082177957Sattilio LOCK_LOG3(lk, 1083177957Sattilio "%s: %p waking up threads on the %s queue", 1084177957Sattilio __func__, lk, queue == SQ_SHARED_QUEUE ? "shared" : 1085177957Sattilio "exclusive"); 1086177957Sattilio atomic_store_rel_ptr(&lk->lk_lock, v); 1087200447Sattilio wakeup_swapper |= sleepq_broadcast(&lk->lock_object, 1088181334Sjhb SLEEPQ_LK, 0, queue); 1089177957Sattilio sleepq_release(&lk->lock_object); 1090177957Sattilio break; 1091177957Sattilio } else 1092181334Sjhb wakeup_swapper = wakeupshlk(lk, file, line); 109324269Speter break; 1094177957Sattilio case LK_DRAIN: 1095178159Sattilio if (LK_CAN_WITNESS(flags)) 1096178159Sattilio WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER | 1097251326Sjhb LOP_EXCLUSIVE, file, line, flags & LK_INTERLOCK ? 1098251326Sjhb ilk : NULL); 109924269Speter 110024269Speter /* 1101180798Skib * Trying to drain a lock we already own will result in a 1102177957Sattilio * deadlock. 110324269Speter */ 1104177957Sattilio if (lockmgr_xlocked(lk)) { 1105177957Sattilio if (flags & LK_INTERLOCK) 1106177957Sattilio class->lc_unlock(ilk); 1107177957Sattilio panic("%s: draining %s with the lock held @ %s:%d\n", 1108177957Sattilio __func__, iwmesg, file, line); 1109177957Sattilio } 111028345Sdyson 1111177957Sattilio while (!atomic_cmpset_acq_ptr(&lk->lk_lock, LK_UNLOCKED, tid)) { 1112233628Sfabient#ifdef HWPMC_HOOKS 1113233628Sfabient PMC_SOFT_CALL( , , lock, failed); 1114233628Sfabient#endif 1115177957Sattilio lock_profile_obtain_lock_failed(&lk->lock_object, 1116177957Sattilio &contested, &waittime); 111724269Speter 1118177957Sattilio /* 1119177957Sattilio * If the lock is expected to not sleep just give up 1120177957Sattilio * and return. 1121177957Sattilio */ 1122177957Sattilio if (LK_TRYOP(flags)) { 1123177957Sattilio LOCK_LOG2(lk, "%s: %p fails the try operation", 1124177957Sattilio __func__, lk); 1125177957Sattilio error = EBUSY; 1126177957Sattilio break; 1127177957Sattilio } 112824269Speter 1129177957Sattilio /* 1130177957Sattilio * Acquire the sleepqueue chain lock because we 1131177957Sattilio * probabilly will need to manipulate waiters flags. 1132177957Sattilio */ 1133177957Sattilio sleepq_lock(&lk->lock_object); 1134177957Sattilio x = lk->lk_lock; 113529653Sdyson 1136177957Sattilio /* 1137177957Sattilio * if the lock has been released while we spun on 1138177957Sattilio * the sleepqueue chain lock just try again. 1139177957Sattilio */ 1140177957Sattilio if (x == LK_UNLOCKED) { 1141177957Sattilio sleepq_release(&lk->lock_object); 1142177957Sattilio continue; 1143177957Sattilio } 1144176320Sattilio 1145194317Sattilio v = x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); 1146194317Sattilio if ((x & ~v) == LK_UNLOCKED) { 1147194317Sattilio v = (x & ~LK_EXCLUSIVE_SPINNERS); 1148200447Sattilio 1149200447Sattilio /* 1150200447Sattilio * If interruptible sleeps left the exclusive 1151200447Sattilio * queue empty avoid a starvation for the 1152200447Sattilio * threads sleeping on the shared queue by 1153200447Sattilio * giving them precedence and cleaning up the 1154200447Sattilio * exclusive waiters bit anyway. 1155201709Sattilio * Please note that lk_exslpfail count may be 1156201709Sattilio * lying about the real number of waiters with 1157201709Sattilio * the LK_SLEEPFAIL flag on because they may 1158201709Sattilio * be used in conjuction with interruptible 1159201710Sattilio * sleeps so lk_exslpfail might be considered 1160201710Sattilio * an 'upper limit' bound, including the edge 1161201709Sattilio * cases. 1162200447Sattilio */ 1163177957Sattilio if (v & LK_EXCLUSIVE_WAITERS) { 1164177957Sattilio queue = SQ_EXCLUSIVE_QUEUE; 1165177957Sattilio v &= ~LK_EXCLUSIVE_WAITERS; 1166177957Sattilio } else { 1167201703Sattilio 1168201703Sattilio /* 1169201703Sattilio * Exclusive waiters sleeping with 1170201703Sattilio * LK_SLEEPFAIL on and using 1171201703Sattilio * interruptible sleeps/timeout may 1172201703Sattilio * have left spourious lk_exslpfail 1173201703Sattilio * counts on, so clean it up anyway. 1174201703Sattilio */ 1175177957Sattilio MPASS(v & LK_SHARED_WAITERS); 1176201703Sattilio lk->lk_exslpfail = 0; 1177177957Sattilio queue = SQ_SHARED_QUEUE; 1178177957Sattilio v &= ~LK_SHARED_WAITERS; 1179177957Sattilio } 1180200447Sattilio if (queue == SQ_EXCLUSIVE_QUEUE) { 1181200447Sattilio realexslp = 1182200447Sattilio sleepq_sleepcnt(&lk->lock_object, 1183200447Sattilio SQ_EXCLUSIVE_QUEUE); 1184200447Sattilio if (lk->lk_exslpfail >= realexslp) { 1185200447Sattilio lk->lk_exslpfail = 0; 1186200447Sattilio queue = SQ_SHARED_QUEUE; 1187200447Sattilio v &= ~LK_SHARED_WAITERS; 1188200447Sattilio if (realexslp != 0) { 1189200447Sattilio LOCK_LOG2(lk, 1190200447Sattilio "%s: %p has only LK_SLEEPFAIL sleepers", 1191200447Sattilio __func__, lk); 1192200447Sattilio LOCK_LOG2(lk, 1193200447Sattilio "%s: %p waking up threads on the exclusive queue", 1194200447Sattilio __func__, lk); 1195200447Sattilio wakeup_swapper = 1196200447Sattilio sleepq_broadcast( 1197200447Sattilio &lk->lock_object, 1198200447Sattilio SLEEPQ_LK, 0, 1199200447Sattilio SQ_EXCLUSIVE_QUEUE); 1200200447Sattilio } 1201200447Sattilio } else 1202200447Sattilio lk->lk_exslpfail = 0; 1203200447Sattilio } 1204177957Sattilio if (!atomic_cmpset_ptr(&lk->lk_lock, x, v)) { 1205177957Sattilio sleepq_release(&lk->lock_object); 1206177957Sattilio continue; 1207177957Sattilio } 1208177957Sattilio LOCK_LOG3(lk, 1209177957Sattilio "%s: %p waking up all threads on the %s queue", 1210177957Sattilio __func__, lk, queue == SQ_SHARED_QUEUE ? 1211177957Sattilio "shared" : "exclusive"); 1212182010Sjhb wakeup_swapper |= sleepq_broadcast( 1213181334Sjhb &lk->lock_object, SLEEPQ_LK, 0, queue); 1214177957Sattilio 1215177957Sattilio /* 1216177957Sattilio * If shared waiters have been woken up we need 1217177957Sattilio * to wait for one of them to acquire the lock 1218177957Sattilio * before to set the exclusive waiters in 1219177957Sattilio * order to avoid a deadlock. 1220177957Sattilio */ 1221177957Sattilio if (queue == SQ_SHARED_QUEUE) { 1222177957Sattilio for (v = lk->lk_lock; 1223177957Sattilio (v & LK_SHARE) && !LK_SHARERS(v); 1224177957Sattilio v = lk->lk_lock) 1225177957Sattilio cpu_spinwait(); 1226177957Sattilio } 1227177957Sattilio } 1228177957Sattilio 1229177957Sattilio /* 1230177957Sattilio * Try to set the LK_EXCLUSIVE_WAITERS flag. If we 1231177957Sattilio * fail, loop back and retry. 1232177957Sattilio */ 1233177957Sattilio if ((x & LK_EXCLUSIVE_WAITERS) == 0) { 1234177957Sattilio if (!atomic_cmpset_ptr(&lk->lk_lock, x, 1235177957Sattilio x | LK_EXCLUSIVE_WAITERS)) { 1236177957Sattilio sleepq_release(&lk->lock_object); 1237177957Sattilio continue; 1238177957Sattilio } 1239177957Sattilio LOCK_LOG2(lk, "%s: %p set drain waiters flag", 1240177957Sattilio __func__, lk); 1241177957Sattilio } 1242177957Sattilio 1243177957Sattilio /* 1244177957Sattilio * As far as we have been unable to acquire the 1245177957Sattilio * exclusive lock and the exclusive waiters flag 1246177957Sattilio * is set, we will sleep. 1247177957Sattilio */ 1248177957Sattilio if (flags & LK_INTERLOCK) { 1249177957Sattilio class->lc_unlock(ilk); 1250177957Sattilio flags &= ~LK_INTERLOCK; 1251177957Sattilio } 1252178159Sattilio GIANT_SAVE(); 1253177957Sattilio sleepq_add(&lk->lock_object, NULL, iwmesg, SLEEPQ_LK, 1254177957Sattilio SQ_EXCLUSIVE_QUEUE); 1255177957Sattilio sleepq_wait(&lk->lock_object, ipri & PRIMASK); 1256178159Sattilio GIANT_RESTORE(); 1257177957Sattilio LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", 1258177957Sattilio __func__, lk); 125929653Sdyson } 1260177957Sattilio 1261177957Sattilio if (error == 0) { 1262177957Sattilio lock_profile_obtain_lock_success(&lk->lock_object, 1263177957Sattilio contested, waittime, file, line); 1264177957Sattilio LOCK_LOG_LOCK("DRAIN", &lk->lock_object, 0, 1265177957Sattilio lk->lk_recurse, file, line); 1266178159Sattilio WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | 1267178159Sattilio LK_TRYWIT(flags), file, line); 1268177957Sattilio TD_LOCKS_INC(curthread); 1269177957Sattilio STACK_SAVE(lk); 1270177957Sattilio } 1271177957Sattilio break; 1272177957Sattilio default: 1273177957Sattilio if (flags & LK_INTERLOCK) 1274177957Sattilio class->lc_unlock(ilk); 1275177957Sattilio panic("%s: unknown lockmgr request 0x%x\n", __func__, op); 127629653Sdyson } 1277177957Sattilio 1278177957Sattilio if (flags & LK_INTERLOCK) 1279177957Sattilio class->lc_unlock(ilk); 1280181334Sjhb if (wakeup_swapper) 1281181334Sjhb kick_proc0(); 1282177957Sattilio 1283177957Sattilio return (error); 128429653Sdyson} 128529653Sdyson 128629653Sdysonvoid 1287177957Sattilio_lockmgr_disown(struct lock *lk, const char *file, int line) 128829653Sdyson{ 1289177957Sattilio uintptr_t tid, x; 1290176014Sattilio 1291228424Savg if (SCHEDULER_STOPPED()) 1292228424Savg return; 1293228424Savg 1294177957Sattilio tid = (uintptr_t)curthread; 1295243900Sattilio _lockmgr_assert(lk, KA_XLOCKED, file, line); 129629653Sdyson 1297177957Sattilio /* 1298243900Sattilio * Panic if the lock is recursed. 1299243900Sattilio */ 1300243900Sattilio if (lockmgr_xlocked(lk) && lockmgr_recursed(lk)) 1301243900Sattilio panic("%s: disown a recursed lockmgr @ %s:%d\n", 1302243900Sattilio __func__, file, line); 1303243900Sattilio 1304243900Sattilio /* 1305180798Skib * If the owner is already LK_KERNPROC just skip the whole operation. 1306177957Sattilio */ 1307177957Sattilio if (LK_HOLDER(lk->lk_lock) != tid) 1308177957Sattilio return; 1309189788Sjeff lock_profile_release_lock(&lk->lock_object); 1310178159Sattilio LOCK_LOG_LOCK("XDISOWN", &lk->lock_object, 0, 0, file, line); 1311178159Sattilio WITNESS_UNLOCK(&lk->lock_object, LOP_EXCLUSIVE, file, line); 1312178159Sattilio TD_LOCKS_DEC(curthread); 1313199008Sattilio STACK_SAVE(lk); 131429653Sdyson 1315177957Sattilio /* 1316177957Sattilio * In order to preserve waiters flags, just spin. 1317177957Sattilio */ 1318177957Sattilio for (;;) { 1319194317Sattilio x = lk->lk_lock; 1320194317Sattilio MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); 1321194317Sattilio x &= LK_ALL_WAITERS; 1322178166Sattilio if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid | x, 1323178159Sattilio LK_KERNPROC | x)) 1324177957Sattilio return; 1325177957Sattilio cpu_spinwait(); 1326177957Sattilio } 132766615Sjasone} 132866615Sjasone 1329175166Sattiliovoid 1330227588Spjdlockmgr_printinfo(const struct lock *lk) 1331175166Sattilio{ 1332175166Sattilio struct thread *td; 1333177957Sattilio uintptr_t x; 1334175166Sattilio 1335177957Sattilio if (lk->lk_lock == LK_UNLOCKED) 1336188244Sjhb printf("lock type %s: UNLOCKED\n", lk->lock_object.lo_name); 1337177957Sattilio else if (lk->lk_lock & LK_SHARE) 1338188244Sjhb printf("lock type %s: SHARED (count %ju)\n", 1339177957Sattilio lk->lock_object.lo_name, 1340177957Sattilio (uintmax_t)LK_SHARERS(lk->lk_lock)); 1341177957Sattilio else { 1342177957Sattilio td = lockmgr_xholder(lk); 1343232547Sivoras printf("lock type %s: EXCL by thread %p " 1344232547Sivoras "(pid %d, %s, tid %d)\n", lk->lock_object.lo_name, td, 1345232547Sivoras td->td_proc->p_pid, td->td_proc->p_comm, td->td_tid); 1346177957Sattilio } 1347175166Sattilio 1348177957Sattilio x = lk->lk_lock; 1349177957Sattilio if (x & LK_EXCLUSIVE_WAITERS) 1350177957Sattilio printf(" with exclusive waiters pending\n"); 1351177957Sattilio if (x & LK_SHARED_WAITERS) 1352177957Sattilio printf(" with shared waiters pending\n"); 1353194317Sattilio if (x & LK_EXCLUSIVE_SPINNERS) 1354194317Sattilio printf(" with exclusive spinners pending\n"); 1355177957Sattilio 1356177957Sattilio STACK_PRINT(lk); 1357175166Sattilio} 1358175166Sattilio 135929653Sdysonint 1360227588Spjdlockstatus(const struct lock *lk) 136129653Sdyson{ 1362177957Sattilio uintptr_t v, x; 1363177957Sattilio int ret; 136429653Sdyson 1365177957Sattilio ret = LK_SHARED; 1366177957Sattilio x = lk->lk_lock; 1367177957Sattilio v = LK_HOLDER(x); 1368175635Sattilio 1369177957Sattilio if ((x & LK_SHARE) == 0) { 1370177957Sattilio if (v == (uintptr_t)curthread || v == LK_KERNPROC) 1371177957Sattilio ret = LK_EXCLUSIVE; 137254444Seivind else 1373177957Sattilio ret = LK_EXCLOTHER; 1374177957Sattilio } else if (x == LK_UNLOCKED) 1375177957Sattilio ret = 0; 137629653Sdyson 1377177957Sattilio return (ret); 137824269Speter} 1379161322Sjhb 1380176249Sattilio#ifdef INVARIANT_SUPPORT 1381219028Snetchild 1382219028SnetchildFEATURE(invariant_support, 1383219028Snetchild "Support for modules compiled with INVARIANTS option"); 1384219028Snetchild 1385176249Sattilio#ifndef INVARIANTS 1386177957Sattilio#undef _lockmgr_assert 1387176249Sattilio#endif 1388176249Sattilio 1389176249Sattiliovoid 1390227588Spjd_lockmgr_assert(const struct lock *lk, int what, const char *file, int line) 1391176249Sattilio{ 1392176249Sattilio int slocked = 0; 1393176249Sattilio 1394176249Sattilio if (panicstr != NULL) 1395176249Sattilio return; 1396176249Sattilio switch (what) { 1397176249Sattilio case KA_SLOCKED: 1398176249Sattilio case KA_SLOCKED | KA_NOTRECURSED: 1399176249Sattilio case KA_SLOCKED | KA_RECURSED: 1400176249Sattilio slocked = 1; 1401176249Sattilio case KA_LOCKED: 1402176249Sattilio case KA_LOCKED | KA_NOTRECURSED: 1403176249Sattilio case KA_LOCKED | KA_RECURSED: 1404178159Sattilio#ifdef WITNESS 1405178159Sattilio 1406178159Sattilio /* 1407178159Sattilio * We cannot trust WITNESS if the lock is held in exclusive 1408178159Sattilio * mode and a call to lockmgr_disown() happened. 1409178159Sattilio * Workaround this skipping the check if the lock is held in 1410178159Sattilio * exclusive mode even for the KA_LOCKED case. 1411178159Sattilio */ 1412178159Sattilio if (slocked || (lk->lk_lock & LK_SHARE)) { 1413178159Sattilio witness_assert(&lk->lock_object, what, file, line); 1414178159Sattilio break; 1415178159Sattilio } 1416178159Sattilio#endif 1417177957Sattilio if (lk->lk_lock == LK_UNLOCKED || 1418177957Sattilio ((lk->lk_lock & LK_SHARE) == 0 && (slocked || 1419177957Sattilio (!lockmgr_xlocked(lk) && !lockmgr_disowned(lk))))) 1420176249Sattilio panic("Lock %s not %slocked @ %s:%d\n", 1421177957Sattilio lk->lock_object.lo_name, slocked ? "share" : "", 1422176249Sattilio file, line); 1423177957Sattilio 1424177957Sattilio if ((lk->lk_lock & LK_SHARE) == 0) { 1425177957Sattilio if (lockmgr_recursed(lk)) { 1426176249Sattilio if (what & KA_NOTRECURSED) 1427176249Sattilio panic("Lock %s recursed @ %s:%d\n", 1428177957Sattilio lk->lock_object.lo_name, file, 1429177957Sattilio line); 1430176249Sattilio } else if (what & KA_RECURSED) 1431176249Sattilio panic("Lock %s not recursed @ %s:%d\n", 1432177957Sattilio lk->lock_object.lo_name, file, line); 1433176249Sattilio } 1434176249Sattilio break; 1435176249Sattilio case KA_XLOCKED: 1436176249Sattilio case KA_XLOCKED | KA_NOTRECURSED: 1437176249Sattilio case KA_XLOCKED | KA_RECURSED: 1438177957Sattilio if (!lockmgr_xlocked(lk) && !lockmgr_disowned(lk)) 1439176249Sattilio panic("Lock %s not exclusively locked @ %s:%d\n", 1440177957Sattilio lk->lock_object.lo_name, file, line); 1441177957Sattilio if (lockmgr_recursed(lk)) { 1442176249Sattilio if (what & KA_NOTRECURSED) 1443176249Sattilio panic("Lock %s recursed @ %s:%d\n", 1444177957Sattilio lk->lock_object.lo_name, file, line); 1445176249Sattilio } else if (what & KA_RECURSED) 1446176249Sattilio panic("Lock %s not recursed @ %s:%d\n", 1447177957Sattilio lk->lock_object.lo_name, file, line); 1448176249Sattilio break; 1449176249Sattilio case KA_UNLOCKED: 1450177957Sattilio if (lockmgr_xlocked(lk) || lockmgr_disowned(lk)) 1451176249Sattilio panic("Lock %s exclusively locked @ %s:%d\n", 1452177957Sattilio lk->lock_object.lo_name, file, line); 1453176249Sattilio break; 1454176249Sattilio default: 1455177957Sattilio panic("Unknown lockmgr assertion: %d @ %s:%d\n", what, file, 1456177957Sattilio line); 1457176249Sattilio } 1458176249Sattilio} 1459177957Sattilio#endif 1460176249Sattilio 1461161322Sjhb#ifdef DDB 1462161337Sjhbint 1463161337Sjhblockmgr_chain(struct thread *td, struct thread **ownerp) 1464161337Sjhb{ 1465177957Sattilio struct lock *lk; 1466161337Sjhb 1467177957Sattilio lk = td->td_wchan; 1468161337Sjhb 1469177957Sattilio if (LOCK_CLASS(&lk->lock_object) != &lock_class_lockmgr) 1470177957Sattilio return (0); 1471177957Sattilio db_printf("blocked on lockmgr %s", lk->lock_object.lo_name); 1472177957Sattilio if (lk->lk_lock & LK_SHARE) 1473177957Sattilio db_printf("SHARED (count %ju)\n", 1474177957Sattilio (uintmax_t)LK_SHARERS(lk->lk_lock)); 1475177957Sattilio else 1476177957Sattilio db_printf("EXCL\n"); 1477177957Sattilio *ownerp = lockmgr_xholder(lk); 1478161337Sjhb 1479161337Sjhb return (1); 1480161337Sjhb} 1481161337Sjhb 1482177957Sattiliostatic void 1483227588Spjddb_show_lockmgr(const struct lock_object *lock) 1484161322Sjhb{ 1485161322Sjhb struct thread *td; 1486227588Spjd const struct lock *lk; 1487161322Sjhb 1488227588Spjd lk = (const struct lock *)lock; 1489161322Sjhb 1490168070Sjhb db_printf(" state: "); 1491177957Sattilio if (lk->lk_lock == LK_UNLOCKED) 1492161322Sjhb db_printf("UNLOCKED\n"); 1493177957Sattilio else if (lk->lk_lock & LK_SHARE) 1494177957Sattilio db_printf("SLOCK: %ju\n", (uintmax_t)LK_SHARERS(lk->lk_lock)); 1495177957Sattilio else { 1496177957Sattilio td = lockmgr_xholder(lk); 1497177957Sattilio if (td == (struct thread *)LK_KERNPROC) 1498177957Sattilio db_printf("XLOCK: LK_KERNPROC\n"); 1499177957Sattilio else 1500177957Sattilio db_printf("XLOCK: %p (tid %d, pid %d, \"%s\")\n", td, 1501177957Sattilio td->td_tid, td->td_proc->p_pid, 1502177957Sattilio td->td_proc->p_comm); 1503177957Sattilio if (lockmgr_recursed(lk)) 1504177957Sattilio db_printf(" recursed: %d\n", lk->lk_recurse); 1505177957Sattilio } 1506177957Sattilio db_printf(" waiters: "); 1507177957Sattilio switch (lk->lk_lock & LK_ALL_WAITERS) { 1508177957Sattilio case LK_SHARED_WAITERS: 1509177957Sattilio db_printf("shared\n"); 1510192022Strasz break; 1511177957Sattilio case LK_EXCLUSIVE_WAITERS: 1512177957Sattilio db_printf("exclusive\n"); 1513177957Sattilio break; 1514177957Sattilio case LK_ALL_WAITERS: 1515177957Sattilio db_printf("shared and exclusive\n"); 1516177957Sattilio break; 1517177957Sattilio default: 1518177957Sattilio db_printf("none\n"); 1519177957Sattilio } 1520194317Sattilio db_printf(" spinners: "); 1521194317Sattilio if (lk->lk_lock & LK_EXCLUSIVE_SPINNERS) 1522194317Sattilio db_printf("exclusive\n"); 1523194317Sattilio else 1524194317Sattilio db_printf("none\n"); 1525161322Sjhb} 1526161322Sjhb#endif 1527