kern_mutex.c revision 104157
1100966Siwasaki/*- 2100966Siwasaki * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved. 3100966Siwasaki * 4167802Sjkim * Redistribution and use in source and binary forms, with or without 5100966Siwasaki * modification, are permitted provided that the following conditions 6100966Siwasaki * are met: 7100966Siwasaki * 1. Redistributions of source code must retain the above copyright 8100966Siwasaki * notice, this list of conditions and the following disclaimer. 9100966Siwasaki * 2. Redistributions in binary form must reproduce the above copyright 10100966Siwasaki * notice, this list of conditions and the following disclaimer in the 11100966Siwasaki * documentation and/or other materials provided with the distribution. 12167802Sjkim * 3. Berkeley Software Design Inc's name may not be used to endorse or 13100966Siwasaki * promote products derived from this software without specific prior 14100966Siwasaki * written permission. 15100966Siwasaki * 16100966Siwasaki * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 17100966Siwasaki * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18100966Siwasaki * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19100966Siwasaki * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 20100966Siwasaki * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21100966Siwasaki * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22100966Siwasaki * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23100966Siwasaki * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24100966Siwasaki * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25100966Siwasaki * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26100966Siwasaki * SUCH DAMAGE. 27100966Siwasaki * 28100966Siwasaki * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $ 29100966Siwasaki * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $ 30100966Siwasaki * $FreeBSD: head/sys/kern/kern_mutex.c 104157 2002-09-29 23:04:34Z julian $ 31100966Siwasaki */ 32100966Siwasaki 33100966Siwasaki/* 34100966Siwasaki * Machine independent bits of mutex implementation. 35100966Siwasaki */ 36100966Siwasaki 37100966Siwasaki#include "opt_adaptive_mutexes.h" 38100966Siwasaki#include "opt_ddb.h" 39100966Siwasaki 40100966Siwasaki#include <sys/param.h> 41100966Siwasaki#include <sys/systm.h> 42100966Siwasaki#include <sys/bus.h> 43100966Siwasaki#include <sys/kernel.h> 44100966Siwasaki#include <sys/ktr.h> 45100966Siwasaki#include <sys/lock.h> 46100966Siwasaki#include <sys/malloc.h> 47100966Siwasaki#include <sys/mutex.h> 48100966Siwasaki#include <sys/proc.h> 49100966Siwasaki#include <sys/resourcevar.h> 50100966Siwasaki#include <sys/sbuf.h> 51100966Siwasaki#include <sys/stdint.h> 52100966Siwasaki#include <sys/sysctl.h> 53100966Siwasaki#include <sys/vmmeter.h> 54100966Siwasaki 55100966Siwasaki#include <machine/atomic.h> 56100966Siwasaki#include <machine/bus.h> 57100966Siwasaki#include <machine/clock.h> 58100966Siwasaki#include <machine/cpu.h> 59100966Siwasaki 60100966Siwasaki#include <ddb/ddb.h> 61100966Siwasaki 62100966Siwasaki#include <vm/vm.h> 63100966Siwasaki#include <vm/vm_extern.h> 64100966Siwasaki 65100966Siwasaki/* 66100966Siwasaki * Internal utility macros. 67100966Siwasaki */ 68100966Siwasaki#define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED) 69100966Siwasaki 70100966Siwasaki#define mtx_owner(m) (mtx_unowned((m)) ? NULL \ 71100966Siwasaki : (struct thread *)((m)->mtx_lock & MTX_FLAGMASK)) 72100966Siwasaki 73100966Siwasaki/* XXXKSE This test will change. */ 74100966Siwasaki#define thread_running(td) \ 75100966Siwasaki ((td)->td_kse != NULL && (td)->td_kse->ke_oncpu != NOCPU) 76100966Siwasaki 77100966Siwasaki/* 78100966Siwasaki * Lock classes for sleep and spin mutexes. 79100966Siwasaki */ 80100966Siwasakistruct lock_class lock_class_mtx_sleep = { 81100966Siwasaki "sleep mutex", 82100966Siwasaki LC_SLEEPLOCK | LC_RECURSABLE 83100966Siwasaki}; 84100966Siwasakistruct lock_class lock_class_mtx_spin = { 85100966Siwasaki "spin mutex", 86100966Siwasaki LC_SPINLOCK | LC_RECURSABLE 87100966Siwasaki}; 88100966Siwasaki 89100966Siwasaki/* 90100966Siwasaki * System-wide mutexes 91100966Siwasaki */ 92100966Siwasakistruct mtx sched_lock; 93100966Siwasakistruct mtx Giant; 94100966Siwasaki 95100966Siwasaki/* 96100966Siwasaki * Prototypes for non-exported routines. 97100966Siwasaki */ 98100966Siwasakistatic void propagate_priority(struct thread *); 99100966Siwasaki 100100966Siwasakistatic void 101100966Siwasakipropagate_priority(struct thread *td) 102100966Siwasaki{ 103100966Siwasaki int pri = td->td_priority; 104100966Siwasaki struct mtx *m = td->td_blocked; 105100966Siwasaki 106100966Siwasaki mtx_assert(&sched_lock, MA_OWNED); 107100966Siwasaki for (;;) { 108100966Siwasaki struct thread *td1; 109100966Siwasaki 110100966Siwasaki td = mtx_owner(m); 111100966Siwasaki 112100966Siwasaki if (td == NULL) { 113100966Siwasaki /* 114100966Siwasaki * This really isn't quite right. Really 115100966Siwasaki * ought to bump priority of thread that 116100966Siwasaki * next acquires the mutex. 117100966Siwasaki */ 118151600Sobrien MPASS(m->mtx_lock == MTX_CONTESTED); 119151600Sobrien return; 120151600Sobrien } 121151600Sobrien 122151600Sobrien MPASS(td->td_proc != NULL); 123100966Siwasaki MPASS(td->td_proc->p_magic == P_MAGIC); 124100966Siwasaki KASSERT(!TD_IS_SLEEPING(td), ("sleeping thread owns a mutex")); 125100966Siwasaki if (td->td_priority <= pri) /* lower is higher priority */ 126100966Siwasaki return; 127102550Siwasaki 128100966Siwasaki 129100966Siwasaki /* 130100966Siwasaki * If lock holder is actually running, just bump priority. 131151937Sjkim */ 132100966Siwasaki if (TD_IS_RUNNING(td)) { 133151937Sjkim td->td_priority = pri; 134100966Siwasaki return; 135151937Sjkim } 136151937Sjkim 137151937Sjkim#ifndef SMP 138151937Sjkim /* 139151937Sjkim * For UP, we check to see if td is curthread (this shouldn't 140151937Sjkim * ever happen however as it would mean we are in a deadlock.) 141151937Sjkim */ 142151937Sjkim KASSERT(td != curthread, ("Deadlock detected")); 143151937Sjkim#endif 144151937Sjkim 145151937Sjkim /* 146151937Sjkim * If on run queue move to new run queue, and quit. 147151937Sjkim * XXXKSE this gets a lot more complicated under threads 148151937Sjkim * but try anyhow. 149151937Sjkim * We should have a special call to do this more efficiently. 150151937Sjkim */ 151151937Sjkim if (TD_ON_RUNQ(td)) { 152100966Siwasaki MPASS(td->td_blocked == NULL); 153100966Siwasaki remrunqueue(td); 154100966Siwasaki td->td_priority = pri; 155100966Siwasaki setrunqueue(td); 156151937Sjkim return; 157151937Sjkim } 158100966Siwasaki /* 159100966Siwasaki * Adjust for any other cases. 160100966Siwasaki */ 161100966Siwasaki td->td_priority = pri; 162100966Siwasaki 163100966Siwasaki /* 164100966Siwasaki * If we aren't blocked on a mutex, we should be. 165100966Siwasaki */ 166100966Siwasaki KASSERT(TD_ON_MUTEX(td), ( 167100966Siwasaki "process %d(%s):%d holds %s but isn't blocked on a mutex\n", 168100966Siwasaki td->td_proc->p_pid, td->td_proc->p_comm, td->td_state, 169100966Siwasaki m->mtx_object.lo_name)); 170100966Siwasaki 171100966Siwasaki /* 172100966Siwasaki * Pick up the mutex that td is blocked on. 173100966Siwasaki */ 174100966Siwasaki m = td->td_blocked; 175100966Siwasaki MPASS(m != NULL); 176100966Siwasaki 177100966Siwasaki /* 178100966Siwasaki * Check if the thread needs to be moved up on 179100966Siwasaki * the blocked chain 180100966Siwasaki */ 181100966Siwasaki if (td == TAILQ_FIRST(&m->mtx_blocked)) { 182167802Sjkim continue; 183100966Siwasaki } 184167802Sjkim 185151937Sjkim td1 = TAILQ_PREV(td, threadqueue, td_blkq); 186100966Siwasaki if (td1->td_priority <= pri) { 187100966Siwasaki continue; 188100966Siwasaki } 189100966Siwasaki 190100966Siwasaki /* 191100966Siwasaki * Remove thread from blocked chain and determine where 192100966Siwasaki * it should be moved up to. Since we know that td1 has 193100966Siwasaki * a lower priority than td, we know that at least one 194100966Siwasaki * thread in the chain has a lower priority and that 195151937Sjkim * td1 will thus not be NULL after the loop. 196151937Sjkim */ 197100966Siwasaki TAILQ_REMOVE(&m->mtx_blocked, td, td_blkq); 198100966Siwasaki TAILQ_FOREACH(td1, &m->mtx_blocked, td_blkq) { 199100966Siwasaki MPASS(td1->td_proc->p_magic == P_MAGIC); 200100966Siwasaki if (td1->td_priority > pri) 201100966Siwasaki break; 202100966Siwasaki } 203100966Siwasaki 204100966Siwasaki MPASS(td1 != NULL); 205100966Siwasaki TAILQ_INSERT_BEFORE(td1, td, td_blkq); 206167802Sjkim CTR4(KTR_LOCK, 207100966Siwasaki "propagate_priority: p %p moved before %p on [%p] %s", 208100966Siwasaki td, td1, m, m->mtx_object.lo_name); 209100966Siwasaki } 210100966Siwasaki} 211100966Siwasaki 212100966Siwasaki#ifdef MUTEX_PROFILING 213100966SiwasakiSYSCTL_NODE(_debug, OID_AUTO, mutex, CTLFLAG_RD, NULL, "mutex debugging"); 214100966SiwasakiSYSCTL_NODE(_debug_mutex, OID_AUTO, prof, CTLFLAG_RD, NULL, "mutex profiling"); 215100966Siwasakistatic int mutex_prof_enable = 0; 216100966SiwasakiSYSCTL_INT(_debug_mutex_prof, OID_AUTO, enable, CTLFLAG_RW, 217100966Siwasaki &mutex_prof_enable, 0, "Enable tracing of mutex holdtime"); 218100966Siwasaki 219100966Siwasakistruct mutex_prof { 220100966Siwasaki const char *name; 221100966Siwasaki const char *file; 222100966Siwasaki int line; 223100966Siwasaki#define MPROF_MAX 0 224100966Siwasaki#define MPROF_TOT 1 225100966Siwasaki#define MPROF_CNT 2 226100966Siwasaki#define MPROF_AVG 3 227167802Sjkim uintmax_t counter[4]; 228100966Siwasaki struct mutex_prof *next; 229167802Sjkim}; 230167802Sjkim 231167802Sjkim/* 232167802Sjkim * mprof_buf is a static pool of profiling records to avoid possible 233167802Sjkim * reentrance of the memory allocation functions. 234100966Siwasaki * 235100966Siwasaki * Note: NUM_MPROF_BUFFERS must be smaller than MPROF_HASH_SIZE. 236100966Siwasaki */ 237100966Siwasaki#define NUM_MPROF_BUFFERS 1000 238117521Snjlstatic struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS]; 239117521Snjlstatic int first_free_mprof_buf; 240100966Siwasaki#define MPROF_HASH_SIZE 1009 241100966Siwasakistatic struct mutex_prof *mprof_hash[MPROF_HASH_SIZE]; 242100966Siwasaki 243100966Siwasakistatic int mutex_prof_acquisitions; 244100966SiwasakiSYSCTL_INT(_debug_mutex_prof, OID_AUTO, acquisitions, CTLFLAG_RD, 245100966Siwasaki &mutex_prof_acquisitions, 0, "Number of mutex acquistions recorded"); 246100966Siwasakistatic int mutex_prof_records; 247100966SiwasakiSYSCTL_INT(_debug_mutex_prof, OID_AUTO, records, CTLFLAG_RD, 248100966Siwasaki &mutex_prof_records, 0, "Number of profiling records"); 249100966Siwasakistatic int mutex_prof_maxrecords = NUM_MPROF_BUFFERS; 250100966SiwasakiSYSCTL_INT(_debug_mutex_prof, OID_AUTO, maxrecords, CTLFLAG_RD, 251100966Siwasaki &mutex_prof_maxrecords, 0, "Maximum number of profiling records"); 252100966Siwasakistatic int mutex_prof_rejected; 253100966SiwasakiSYSCTL_INT(_debug_mutex_prof, OID_AUTO, rejected, CTLFLAG_RD, 254100966Siwasaki &mutex_prof_rejected, 0, "Number of rejected profiling records"); 255100966Siwasakistatic int mutex_prof_hashsize = MPROF_HASH_SIZE; 256100966SiwasakiSYSCTL_INT(_debug_mutex_prof, OID_AUTO, hashsize, CTLFLAG_RD, 257100966Siwasaki &mutex_prof_hashsize, 0, "Hash size"); 258100966Siwasakistatic int mutex_prof_collisions = 0; 259100966SiwasakiSYSCTL_INT(_debug_mutex_prof, OID_AUTO, collisions, CTLFLAG_RD, 260100966Siwasaki &mutex_prof_collisions, 0, "Number of hash collisions"); 261100966Siwasaki 262100966Siwasaki/* 263100966Siwasaki * mprof_mtx protects the profiling buffers and the hash. 264100966Siwasaki */ 265100966Siwasakistatic struct mtx mprof_mtx; 266100966SiwasakiMTX_SYSINIT(mprof, &mprof_mtx, "mutex profiling lock", MTX_SPIN | MTX_QUIET); 267100966Siwasaki 268100966Siwasakistatic u_int64_t 269100966Siwasakinanoseconds(void) 270100966Siwasaki{ 271100966Siwasaki struct timespec tv; 272100966Siwasaki 273100966Siwasaki nanotime(&tv); 274100966Siwasaki return (tv.tv_sec * (u_int64_t)1000000000 + tv.tv_nsec); 275100966Siwasaki} 276100966Siwasaki 277100966Siwasakistatic int 278100966Siwasakidump_mutex_prof_stats(SYSCTL_HANDLER_ARGS) 279100966Siwasaki{ 280100966Siwasaki struct sbuf *sb; 281100966Siwasaki int error, i; 282100966Siwasaki 283100966Siwasaki if (first_free_mprof_buf == 0) 284100966Siwasaki return SYSCTL_OUT(req, "No locking recorded", 285100966Siwasaki sizeof("No locking recorded")); 286100966Siwasaki 287100966Siwasaki sb = sbuf_new(NULL, NULL, 1024, SBUF_AUTOEXTEND); 288100966Siwasaki sbuf_printf(sb, "%12s %12s %12s %12s %s\n", 289100966Siwasaki "max", "total", "count", "average", "name"); 290100966Siwasaki mtx_lock_spin(&mprof_mtx); 291100966Siwasaki for (i = 0; i < first_free_mprof_buf; ++i) 292100966Siwasaki sbuf_printf(sb, "%12ju %12ju %12ju %12ju %s:%d (%s)\n", 293100966Siwasaki mprof_buf[i].counter[MPROF_MAX] / 1000, 294100966Siwasaki mprof_buf[i].counter[MPROF_TOT] / 1000, 295100966Siwasaki mprof_buf[i].counter[MPROF_CNT], 296100966Siwasaki mprof_buf[i].counter[MPROF_AVG] / 1000, 297100966Siwasaki mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name); 298100966Siwasaki mtx_unlock_spin(&mprof_mtx); 299100966Siwasaki sbuf_finish(sb); 300100966Siwasaki error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1); 301100966Siwasaki sbuf_delete(sb); 302100966Siwasaki return (error); 303100966Siwasaki} 304100966SiwasakiSYSCTL_PROC(_debug_mutex_prof, OID_AUTO, stats, CTLTYPE_STRING|CTLFLAG_RD, 305100966Siwasaki NULL, 0, dump_mutex_prof_stats, "A", "Mutex profiling statistics"); 306100966Siwasaki#endif 307100966Siwasaki 308100966Siwasaki/* 309151937Sjkim * Function versions of the inlined __mtx_* macros. These are used by 310100966Siwasaki * modules and can also be called from assembly language if needed. 311100966Siwasaki */ 312100966Siwasakivoid 313100966Siwasaki_mtx_lock_flags(struct mtx *m, int opts, const char *file, int line) 314100966Siwasaki{ 315151937Sjkim 316100966Siwasaki MPASS(curthread != NULL); 317100966Siwasaki KASSERT(m->mtx_object.lo_class == &lock_class_mtx_sleep, 318100966Siwasaki ("mtx_lock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name, 319100966Siwasaki file, line)); 320100966Siwasaki _get_sleep_lock(m, curthread, opts, file, line); 321100966Siwasaki LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file, 322100966Siwasaki line); 323100966Siwasaki WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 324100966Siwasaki#ifdef MUTEX_PROFILING 325100966Siwasaki /* don't reset the timer when/if recursing */ 326100966Siwasaki if (m->mtx_acqtime == 0) { 327100966Siwasaki m->mtx_filename = file; 328100966Siwasaki m->mtx_lineno = line; 329100966Siwasaki m->mtx_acqtime = mutex_prof_enable ? nanoseconds() : 0; 330100966Siwasaki ++mutex_prof_acquisitions; 331100966Siwasaki } 332100966Siwasaki#endif 333100966Siwasaki} 334100966Siwasaki 335100966Siwasakivoid 336100966Siwasaki_mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line) 337100966Siwasaki{ 338100966Siwasaki 339100966Siwasaki MPASS(curthread != NULL); 340100966Siwasaki KASSERT(m->mtx_object.lo_class == &lock_class_mtx_sleep, 341100966Siwasaki ("mtx_unlock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name, 342100966Siwasaki file, line)); 343100966Siwasaki WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 344100966Siwasaki LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file, 345100966Siwasaki line); 346100966Siwasaki mtx_assert(m, MA_OWNED); 347100966Siwasaki#ifdef MUTEX_PROFILING 348100966Siwasaki if (m->mtx_acqtime != 0) { 349100966Siwasaki static const char *unknown = "(unknown)"; 350100966Siwasaki struct mutex_prof *mpp; 351100966Siwasaki u_int64_t acqtime, now; 352100966Siwasaki const char *p, *q; 353100966Siwasaki volatile u_int hash; 354100966Siwasaki 355100966Siwasaki now = nanoseconds(); 356100966Siwasaki acqtime = m->mtx_acqtime; 357100966Siwasaki m->mtx_acqtime = 0; 358100966Siwasaki if (now <= acqtime) 359100966Siwasaki goto out; 360100966Siwasaki for (p = m->mtx_filename; strncmp(p, "../", 3) == 0; p += 3) 361100966Siwasaki /* nothing */ ; 362100966Siwasaki if (p == NULL || *p == '\0') 363100966Siwasaki p = unknown; 364100966Siwasaki for (hash = m->mtx_lineno, q = p; *q != '\0'; ++q) 365100966Siwasaki hash = (hash * 2 + *q) % MPROF_HASH_SIZE; 366100966Siwasaki mtx_lock_spin(&mprof_mtx); 367100966Siwasaki for (mpp = mprof_hash[hash]; mpp != NULL; mpp = mpp->next) 368100966Siwasaki if (mpp->line == m->mtx_lineno && 369100966Siwasaki strcmp(mpp->file, p) == 0) 370100966Siwasaki break; 371100966Siwasaki if (mpp == NULL) { 372100966Siwasaki /* Just exit if we cannot get a trace buffer */ 373100966Siwasaki if (first_free_mprof_buf >= NUM_MPROF_BUFFERS) { 374100966Siwasaki ++mutex_prof_rejected; 375100966Siwasaki goto unlock; 376100966Siwasaki } 377100966Siwasaki mpp = &mprof_buf[first_free_mprof_buf++]; 378100966Siwasaki mpp->name = mtx_name(m); 379100966Siwasaki mpp->file = p; 380100966Siwasaki mpp->line = m->mtx_lineno; 381100966Siwasaki mpp->next = mprof_hash[hash]; 382100966Siwasaki if (mprof_hash[hash] != NULL) 383100966Siwasaki ++mutex_prof_collisions; 384151937Sjkim mprof_hash[hash] = mpp; 385100966Siwasaki ++mutex_prof_records; 386100966Siwasaki } 387100966Siwasaki /* 388100966Siwasaki * Record if the mutex has been held longer now than ever 389100966Siwasaki * before 390100966Siwasaki */ 391100966Siwasaki if ((now - acqtime) > mpp->counter[MPROF_MAX]) 392100966Siwasaki mpp->counter[MPROF_MAX] = now - acqtime; 393100966Siwasaki mpp->counter[MPROF_TOT] += now - acqtime; 394100966Siwasaki mpp->counter[MPROF_CNT] += 1; 395100966Siwasaki mpp->counter[MPROF_AVG] = 396100966Siwasaki mpp->counter[MPROF_TOT] / mpp->counter[MPROF_CNT]; 397100966Siwasakiunlock: 398100966Siwasaki mtx_unlock_spin(&mprof_mtx); 399100966Siwasaki } 400100966Siwasakiout: 401100966Siwasaki#endif 402100966Siwasaki _rel_sleep_lock(m, curthread, opts, file, line); 403100966Siwasaki} 404100966Siwasaki 405100966Siwasakivoid 406100966Siwasaki_mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line) 407100966Siwasaki{ 408100966Siwasaki 409100966Siwasaki MPASS(curthread != NULL); 410100966Siwasaki KASSERT(m->mtx_object.lo_class == &lock_class_mtx_spin, 411100966Siwasaki ("mtx_lock_spin() of sleep mutex %s @ %s:%d", 412100966Siwasaki m->mtx_object.lo_name, file, line)); 413100966Siwasaki#if defined(SMP) || LOCK_DEBUG > 0 || 1 414100966Siwasaki _get_spin_lock(m, curthread, opts, file, line); 415100966Siwasaki#else 416100966Siwasaki critical_enter(); 417100966Siwasaki#endif 418151937Sjkim LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file, 419100966Siwasaki line); 420100966Siwasaki WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 421100966Siwasaki} 422100966Siwasaki 423100966Siwasakivoid 424100966Siwasaki_mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line) 425100966Siwasaki{ 426100966Siwasaki 427100966Siwasaki MPASS(curthread != NULL); 428100966Siwasaki KASSERT(m->mtx_object.lo_class == &lock_class_mtx_spin, 429100966Siwasaki ("mtx_unlock_spin() of sleep mutex %s @ %s:%d", 430100966Siwasaki m->mtx_object.lo_name, file, line)); 431100966Siwasaki WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 432100966Siwasaki LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file, 433100966Siwasaki line); 434100966Siwasaki mtx_assert(m, MA_OWNED); 435100966Siwasaki#if defined(SMP) || LOCK_DEBUG > 0 || 1 436100966Siwasaki _rel_spin_lock(m); 437100966Siwasaki#else 438100966Siwasaki critical_exit(); 439100966Siwasaki#endif 440100966Siwasaki} 441100966Siwasaki 442100966Siwasaki/* 443100966Siwasaki * The important part of mtx_trylock{,_flags}() 444100966Siwasaki * Tries to acquire lock `m.' We do NOT handle recursion here; we assume that 445100966Siwasaki * if we're called, it's because we know we don't already own this lock. 446100966Siwasaki */ 447102550Siwasakiint 448100966Siwasaki_mtx_trylock(struct mtx *m, int opts, const char *file, int line) 449100966Siwasaki{ 450100966Siwasaki int rval; 451100966Siwasaki 452151937Sjkim MPASS(curthread != NULL); 453100966Siwasaki 454100966Siwasaki rval = _obtain_lock(m, curthread); 455100966Siwasaki 456100966Siwasaki LOCK_LOG_TRY("LOCK", &m->mtx_object, opts, rval, file, line); 457100966Siwasaki if (rval) { 458100966Siwasaki /* 459100966Siwasaki * We do not handle recursion in _mtx_trylock; see the 460100966Siwasaki * note at the top of the routine. 461100966Siwasaki */ 462128212Snjl KASSERT(!mtx_recursed(m), 463100966Siwasaki ("mtx_trylock() called on a recursed mutex")); 464100966Siwasaki WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK, 465100966Siwasaki file, line); 466100966Siwasaki } 467100966Siwasaki 468100966Siwasaki return (rval); 469100966Siwasaki} 470100966Siwasaki 471100966Siwasaki/* 472128212Snjl * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock. 473100966Siwasaki * 474100966Siwasaki * We call this if the lock is either contested (i.e. we need to go to 475100966Siwasaki * sleep waiting for it), or if we need to recurse on it. 476100966Siwasaki */ 477100966Siwasakivoid 478151937Sjkim_mtx_lock_sleep(struct mtx *m, int opts, const char *file, int line) 479151937Sjkim{ 480151937Sjkim struct thread *td = curthread; 481151937Sjkim#if defined(SMP) && defined(ADAPTIVE_MUTEXES) 482151937Sjkim struct thread *owner; 483151937Sjkim#endif 484151937Sjkim#ifdef KTR 485100966Siwasaki int cont_logged = 0; 486100966Siwasaki#endif 487100966Siwasaki 488128212Snjl if ((m->mtx_lock & MTX_FLAGMASK) == (uintptr_t)td) { 489128212Snjl m->mtx_recurse++; 490100966Siwasaki atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 491128212Snjl if (LOCK_LOG_TEST(&m->mtx_object, opts)) 492128212Snjl CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); 493128212Snjl return; 494128212Snjl } 495128212Snjl 496151937Sjkim if (LOCK_LOG_TEST(&m->mtx_object, opts)) 497151937Sjkim CTR4(KTR_LOCK, 498151937Sjkim "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", 499151937Sjkim m->mtx_object.lo_name, (void *)m->mtx_lock, file, line); 500128212Snjl 501128212Snjl while (!_obtain_lock(m, td)) { 502167802Sjkim uintptr_t v; 503151937Sjkim struct thread *td1; 504128212Snjl 505167802Sjkim mtx_lock_spin(&sched_lock); 506167802Sjkim /* 507167802Sjkim * Check if the lock has been released while spinning for 508167802Sjkim * the sched_lock. 509167802Sjkim */ 510167802Sjkim if ((v = m->mtx_lock) == MTX_UNOWNED) { 511167802Sjkim mtx_unlock_spin(&sched_lock); 512167802Sjkim#ifdef __i386__ 513167802Sjkim ia32_pause(); 514167802Sjkim#endif 515167802Sjkim continue; 516167802Sjkim } 517167802Sjkim 518167802Sjkim /* 519167802Sjkim * The mutex was marked contested on release. This means that 520167802Sjkim * there are threads blocked on it. 521167802Sjkim */ 522167802Sjkim if (v == MTX_CONTESTED) { 523167802Sjkim td1 = TAILQ_FIRST(&m->mtx_blocked); 524167802Sjkim MPASS(td1 != NULL); 525167802Sjkim m->mtx_lock = (uintptr_t)td | MTX_CONTESTED; 526167802Sjkim 527167802Sjkim if (td1->td_priority < td->td_priority) 528167802Sjkim td->td_priority = td1->td_priority; 529167802Sjkim mtx_unlock_spin(&sched_lock); 530167802Sjkim return; 531167802Sjkim } 532167802Sjkim 533167802Sjkim /* 534128212Snjl * If the mutex isn't already contested and a failure occurs 535167802Sjkim * setting the contested bit, the mutex was either released 536167802Sjkim * or the state of the MTX_RECURSED bit changed. 537129684Snjl */ 538128212Snjl if ((v & MTX_CONTESTED) == 0 && 539128212Snjl !atomic_cmpset_ptr(&m->mtx_lock, (void *)v, 540128212Snjl (void *)(v | MTX_CONTESTED))) { 541128212Snjl mtx_unlock_spin(&sched_lock); 542100966Siwasaki#ifdef __i386__ 543100966Siwasaki ia32_pause(); 544100966Siwasaki#endif 545100966Siwasaki continue; 546100966Siwasaki } 547100966Siwasaki 548100966Siwasaki#if defined(SMP) && defined(ADAPTIVE_MUTEXES) 549151937Sjkim /* 550151937Sjkim * If the current owner of the lock is executing on another 551151937Sjkim * CPU, spin instead of blocking. 552151937Sjkim */ 553100966Siwasaki owner = (struct thread *)(v & MTX_FLAGMASK); 554167802Sjkim if (m != &Giant && thread_running(owner)) { 555167802Sjkim mtx_unlock_spin(&sched_lock); 556100966Siwasaki while (mtx_owner(m) == owner && thread_running(owner)) { 557100966Siwasaki#ifdef __i386__ 558167802Sjkim ia32_pause(); 559167802Sjkim#endif 560167802Sjkim } 561167802Sjkim continue; 562167802Sjkim } 563167802Sjkim#endif /* SMP && ADAPTIVE_MUTEXES */ 564167802Sjkim 565167802Sjkim /* 566167802Sjkim * We definitely must sleep for this lock. 567167802Sjkim */ 568167802Sjkim mtx_assert(m, MA_NOTOWNED); 569167802Sjkim 570167802Sjkim#ifdef notyet 571167802Sjkim /* 572100966Siwasaki * If we're borrowing an interrupted thread's VM context, we 573100966Siwasaki * must clean up before going to sleep. 574100966Siwasaki */ 575100966Siwasaki if (td->td_ithd != NULL) { 576167802Sjkim struct ithd *it = td->td_ithd; 577167802Sjkim 578167802Sjkim if (it->it_interrupted) { 579167802Sjkim if (LOCK_LOG_TEST(&m->mtx_object, opts)) 580167802Sjkim CTR2(KTR_LOCK, 581100966Siwasaki "_mtx_lock_sleep: %p interrupted %p", 582100966Siwasaki it, it->it_interrupted); 583100966Siwasaki intr_thd_fixup(it); 584100966Siwasaki } 585100966Siwasaki } 586100966Siwasaki#endif 587117521Snjl 588117521Snjl /* 589100966Siwasaki * Put us on the list of threads blocked on this mutex. 590100966Siwasaki */ 591102550Siwasaki if (TAILQ_EMPTY(&m->mtx_blocked)) { 592100966Siwasaki td1 = mtx_owner(m); 593100966Siwasaki LIST_INSERT_HEAD(&td1->td_contested, m, mtx_contested); 594100966Siwasaki TAILQ_INSERT_TAIL(&m->mtx_blocked, td, td_blkq); 595100966Siwasaki } else { 596100966Siwasaki TAILQ_FOREACH(td1, &m->mtx_blocked, td_blkq) 597100966Siwasaki if (td1->td_priority > td->td_priority) 598100966Siwasaki break; 599100966Siwasaki if (td1) 600100966Siwasaki TAILQ_INSERT_BEFORE(td1, td, td_blkq); 601117521Snjl else 602117521Snjl TAILQ_INSERT_TAIL(&m->mtx_blocked, td, td_blkq); 603100966Siwasaki } 604100966Siwasaki#ifdef KTR 605100966Siwasaki if (!cont_logged) { 606100966Siwasaki CTR6(KTR_CONTENTION, 607100966Siwasaki "contention: %p at %s:%d wants %s, taken by %s:%d", 608100966Siwasaki td, file, line, m->mtx_object.lo_name, 609100966Siwasaki WITNESS_FILE(&m->mtx_object), 610100966Siwasaki WITNESS_LINE(&m->mtx_object)); 611100966Siwasaki cont_logged = 1; 612100966Siwasaki } 613100966Siwasaki#endif 614100966Siwasaki 615100966Siwasaki /* 616100966Siwasaki * Save who we're blocked on. 617100966Siwasaki */ 618100966Siwasaki td->td_blocked = m; 619100966Siwasaki td->td_mtxname = m->mtx_object.lo_name; 620100966Siwasaki TD_SET_MUTEX(td); 621100966Siwasaki propagate_priority(td); 622100966Siwasaki 623100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 624100966Siwasaki CTR3(KTR_LOCK, 625100966Siwasaki "_mtx_lock_sleep: p %p blocked on [%p] %s", td, m, 626100966Siwasaki m->mtx_object.lo_name); 627100966Siwasaki 628100966Siwasaki td->td_proc->p_stats->p_ru.ru_nvcsw++; 629100966Siwasaki mi_switch(); 630100966Siwasaki 631100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 632100966Siwasaki CTR3(KTR_LOCK, 633100966Siwasaki "_mtx_lock_sleep: p %p free from blocked on [%p] %s", 634100966Siwasaki td, m, m->mtx_object.lo_name); 635100966Siwasaki 636100966Siwasaki mtx_unlock_spin(&sched_lock); 637100966Siwasaki } 638100966Siwasaki 639100966Siwasaki#ifdef KTR 640100966Siwasaki if (cont_logged) { 641100966Siwasaki CTR4(KTR_CONTENTION, 642100966Siwasaki "contention end: %s acquired by %p at %s:%d", 643100966Siwasaki m->mtx_object.lo_name, td, file, line); 644100966Siwasaki } 645100966Siwasaki#endif 646100966Siwasaki return; 647100966Siwasaki} 648100966Siwasaki 649100966Siwasaki/* 650100966Siwasaki * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock. 651151937Sjkim * 652100966Siwasaki * This is only called if we need to actually spin for the lock. Recursion 653100966Siwasaki * is handled inline. 654100966Siwasaki */ 655100966Siwasakivoid 656100966Siwasaki_mtx_lock_spin(struct mtx *m, int opts, const char *file, int line) 657100966Siwasaki{ 658100966Siwasaki int i = 0; 659100966Siwasaki 660100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 661100966Siwasaki CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); 662100966Siwasaki 663100966Siwasaki for (;;) { 664100966Siwasaki if (_obtain_lock(m, curthread)) 665100966Siwasaki break; 666100966Siwasaki 667100966Siwasaki /* Give interrupts a chance while we spin. */ 668100966Siwasaki critical_exit(); 669100966Siwasaki while (m->mtx_lock != MTX_UNOWNED) { 670100966Siwasaki if (i++ < 10000000) { 671100966Siwasaki#ifdef __i386__ 672100966Siwasaki ia32_pause(); 673100966Siwasaki#endif 674100966Siwasaki continue; 675100966Siwasaki } 676100966Siwasaki if (i < 60000000) 677100966Siwasaki DELAY(1); 678100966Siwasaki#ifdef DDB 679100966Siwasaki else if (!db_active) 680100966Siwasaki#else 681100966Siwasaki else 682100966Siwasaki#endif 683100966Siwasaki panic("spin lock %s held by %p for > 5 seconds", 684100966Siwasaki m->mtx_object.lo_name, (void *)m->mtx_lock); 685100966Siwasaki#ifdef __i386__ 686100966Siwasaki ia32_pause(); 687100966Siwasaki#endif 688100966Siwasaki } 689100966Siwasaki critical_enter(); 690100966Siwasaki } 691100966Siwasaki 692167802Sjkim if (LOCK_LOG_TEST(&m->mtx_object, opts)) 693100966Siwasaki CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); 694100966Siwasaki 695100966Siwasaki return; 696100966Siwasaki} 697100966Siwasaki 698100966Siwasaki/* 699100966Siwasaki * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. 700100966Siwasaki * 701100966Siwasaki * We are only called here if the lock is recursed or contested (i.e. we 702100966Siwasaki * need to wake up a blocked thread). 703100966Siwasaki */ 704100966Siwasakivoid 705100966Siwasaki_mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line) 706100966Siwasaki{ 707100966Siwasaki struct thread *td, *td1; 708100966Siwasaki struct mtx *m1; 709100966Siwasaki int pri; 710100966Siwasaki 711100966Siwasaki td = curthread; 712100966Siwasaki 713100966Siwasaki if (mtx_recursed(m)) { 714167802Sjkim if (--(m->mtx_recurse) == 0) 715100966Siwasaki atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); 716100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 717100966Siwasaki CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); 718100966Siwasaki return; 719100966Siwasaki } 720100966Siwasaki 721100966Siwasaki mtx_lock_spin(&sched_lock); 722100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 723100966Siwasaki CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); 724100966Siwasaki 725100966Siwasaki td1 = TAILQ_FIRST(&m->mtx_blocked); 726100966Siwasaki#if defined(SMP) && defined(ADAPTIVE_MUTEXES) 727100966Siwasaki if (td1 == NULL) { 728100966Siwasaki _release_lock_quick(m); 729100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 730100966Siwasaki CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p no sleepers", m); 731100966Siwasaki mtx_unlock_spin(&sched_lock); 732100966Siwasaki return; 733100966Siwasaki } 734100966Siwasaki#endif 735100966Siwasaki MPASS(td->td_proc->p_magic == P_MAGIC); 736100966Siwasaki MPASS(td1->td_proc->p_magic == P_MAGIC); 737100966Siwasaki 738167802Sjkim TAILQ_REMOVE(&m->mtx_blocked, td1, td_blkq); 739100966Siwasaki 740100966Siwasaki if (TAILQ_EMPTY(&m->mtx_blocked)) { 741100966Siwasaki LIST_REMOVE(m, mtx_contested); 742100966Siwasaki _release_lock_quick(m); 743100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 744100966Siwasaki CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p not held", m); 745167802Sjkim } else 746167802Sjkim atomic_store_rel_ptr(&m->mtx_lock, (void *)MTX_CONTESTED); 747167802Sjkim 748167802Sjkim pri = PRI_MAX; 749167802Sjkim LIST_FOREACH(m1, &td->td_contested, mtx_contested) { 750167802Sjkim int cp = TAILQ_FIRST(&m1->mtx_blocked)->td_priority; 751167802Sjkim if (cp < pri) 752167802Sjkim pri = cp; 753100966Siwasaki } 754167802Sjkim 755167802Sjkim if (pri > td->td_base_pri) 756167802Sjkim pri = td->td_base_pri; 757167802Sjkim td->td_priority = pri; 758167802Sjkim 759100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 760100966Siwasaki CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p contested setrunqueue %p", 761100966Siwasaki m, td1); 762100966Siwasaki 763100966Siwasaki td1->td_blocked = NULL; 764100966Siwasaki TD_CLR_MUTEX(td1); 765167802Sjkim if (TD_CAN_RUN(td1)) 766100966Siwasaki setrunqueue(td1); 767100966Siwasaki 768100966Siwasaki if (td->td_critnest == 1 && td1->td_priority < pri) { 769100966Siwasaki#ifdef notyet 770100966Siwasaki if (td->td_ithd != NULL) { 771100966Siwasaki struct ithd *it = td->td_ithd; 772100966Siwasaki 773100966Siwasaki if (it->it_interrupted) { 774100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 775100966Siwasaki CTR2(KTR_LOCK, 776100966Siwasaki "_mtx_unlock_sleep: %p interrupted %p", 777100966Siwasaki it, it->it_interrupted); 778100966Siwasaki intr_thd_fixup(it); 779100966Siwasaki } 780100966Siwasaki } 781100966Siwasaki#endif 782100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 783100966Siwasaki CTR2(KTR_LOCK, 784100966Siwasaki "_mtx_unlock_sleep: %p switching out lock=%p", m, 785100966Siwasaki (void *)m->mtx_lock); 786100966Siwasaki 787100966Siwasaki td->td_proc->p_stats->p_ru.ru_nivcsw++; 788100966Siwasaki mi_switch(); 789100966Siwasaki if (LOCK_LOG_TEST(&m->mtx_object, opts)) 790100966Siwasaki CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p resuming lock=%p", 791100966Siwasaki m, (void *)m->mtx_lock); 792100966Siwasaki } 793100966Siwasaki 794100966Siwasaki mtx_unlock_spin(&sched_lock); 795100966Siwasaki 796100966Siwasaki return; 797102550Siwasaki} 798100966Siwasaki 799100966Siwasaki/* 800100966Siwasaki * All the unlocking of MTX_SPIN locks is done inline. 801100966Siwasaki * See the _rel_spin_lock() macro for the details. 802100966Siwasaki */ 803100966Siwasaki 804100966Siwasaki/* 805100966Siwasaki * The backing function for the INVARIANTS-enabled mtx_assert() 806100966Siwasaki */ 807100966Siwasaki#ifdef INVARIANT_SUPPORT 808100966Siwasakivoid 809100966Siwasaki_mtx_assert(struct mtx *m, int what, const char *file, int line) 810100966Siwasaki{ 811100966Siwasaki 812100966Siwasaki if (panicstr != NULL) 813100966Siwasaki return; 814100966Siwasaki switch (what) { 815100966Siwasaki case MA_OWNED: 816100966Siwasaki case MA_OWNED | MA_RECURSED: 817100966Siwasaki case MA_OWNED | MA_NOTRECURSED: 818100966Siwasaki if (!mtx_owned(m)) 819100966Siwasaki panic("mutex %s not owned at %s:%d", 820100966Siwasaki m->mtx_object.lo_name, file, line); 821100966Siwasaki if (mtx_recursed(m)) { 822100966Siwasaki if ((what & MA_NOTRECURSED) != 0) 823100966Siwasaki panic("mutex %s recursed at %s:%d", 824100966Siwasaki m->mtx_object.lo_name, file, line); 825100966Siwasaki } else if ((what & MA_RECURSED) != 0) { 826100966Siwasaki panic("mutex %s unrecursed at %s:%d", 827100966Siwasaki m->mtx_object.lo_name, file, line); 828100966Siwasaki } 829100966Siwasaki break; 830100966Siwasaki case MA_NOTOWNED: 831100966Siwasaki if (mtx_owned(m)) 832100966Siwasaki panic("mutex %s owned at %s:%d", 833100966Siwasaki m->mtx_object.lo_name, file, line); 834100966Siwasaki break; 835100966Siwasaki default: 836100966Siwasaki panic("unknown mtx_assert at %s:%d", file, line); 837100966Siwasaki } 838100966Siwasaki} 839100966Siwasaki#endif 840100966Siwasaki 841100966Siwasaki/* 842100966Siwasaki * The MUTEX_DEBUG-enabled mtx_validate() 843100966Siwasaki * 844100966Siwasaki * Most of these checks have been moved off into the LO_INITIALIZED flag 845100966Siwasaki * maintained by the witness code. 846100966Siwasaki */ 847100966Siwasaki#ifdef MUTEX_DEBUG 848100966Siwasaki 849100966Siwasakivoid mtx_validate(struct mtx *); 850100966Siwasaki 851100966Siwasakivoid 852100966Siwasakimtx_validate(struct mtx *m) 853100966Siwasaki{ 854100966Siwasaki 855100966Siwasaki/* 856100966Siwasaki * XXX - When kernacc() is fixed on the alpha to handle K0_SEG memory properly 857100966Siwasaki * we can re-enable the kernacc() checks. 858100966Siwasaki */ 859100966Siwasaki#ifndef __alpha__ 860100966Siwasaki /* 861100966Siwasaki * Can't call kernacc() from early init386(), especially when 862100966Siwasaki * initializing Giant mutex, because some stuff in kernacc() 863100966Siwasaki * requires Giant itself. 864100966Siwasaki */ 865100966Siwasaki if (!cold) 866100966Siwasaki if (!kernacc((caddr_t)m, sizeof(m), 867100966Siwasaki VM_PROT_READ | VM_PROT_WRITE)) 868100966Siwasaki panic("Can't read and write to mutex %p", m); 869100966Siwasaki#endif 870100966Siwasaki} 871100966Siwasaki#endif 872100966Siwasaki 873100966Siwasaki/* 874100966Siwasaki * General init routine used by the MTX_SYSINIT() macro. 875100966Siwasaki */ 876151937Sjkimvoid 877100966Siwasakimtx_sysinit(void *arg) 878100966Siwasaki{ 879100966Siwasaki struct mtx_args *margs = arg; 880100966Siwasaki 881100966Siwasaki mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts); 882100966Siwasaki} 883100966Siwasaki 884100966Siwasaki/* 885100966Siwasaki * Mutex initialization routine; initialize lock `m' of type contained in 886100966Siwasaki * `opts' with options contained in `opts' and name `name.' The optional 887100966Siwasaki * lock type `type' is used as a general lock category name for use with 888100966Siwasaki * witness. 889100966Siwasaki */ 890100966Siwasakivoid 891100966Siwasakimtx_init(struct mtx *m, const char *name, const char *type, int opts) 892100966Siwasaki{ 893100966Siwasaki struct lock_object *lock; 894100966Siwasaki 895100966Siwasaki MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | 896100966Siwasaki MTX_SLEEPABLE | MTX_NOWITNESS | MTX_DUPOK)) == 0); 897100966Siwasaki 898100966Siwasaki#ifdef MUTEX_DEBUG 899100966Siwasaki /* Diagnostic and error correction */ 900100966Siwasaki mtx_validate(m); 901100966Siwasaki#endif 902100966Siwasaki 903100966Siwasaki lock = &m->mtx_object; 904100966Siwasaki KASSERT((lock->lo_flags & LO_INITIALIZED) == 0, 905100966Siwasaki ("mutex %s %p already initialized", name, m)); 906100966Siwasaki bzero(m, sizeof(*m)); 907100966Siwasaki if (opts & MTX_SPIN) 908100966Siwasaki lock->lo_class = &lock_class_mtx_spin; 909100966Siwasaki else 910100966Siwasaki lock->lo_class = &lock_class_mtx_sleep; 911100966Siwasaki lock->lo_name = name; 912100966Siwasaki lock->lo_type = type != NULL ? type : name; 913100966Siwasaki if (opts & MTX_QUIET) 914100966Siwasaki lock->lo_flags = LO_QUIET; 915100966Siwasaki if (opts & MTX_RECURSE) 916151937Sjkim lock->lo_flags |= LO_RECURSABLE; 917151937Sjkim if (opts & MTX_SLEEPABLE) 918151937Sjkim lock->lo_flags |= LO_SLEEPABLE; 919151937Sjkim if ((opts & MTX_NOWITNESS) == 0) 920167802Sjkim lock->lo_flags |= LO_WITNESS; 921167802Sjkim if (opts & MTX_DUPOK) 922167802Sjkim lock->lo_flags |= LO_DUPOK; 923167802Sjkim 924100966Siwasaki m->mtx_lock = MTX_UNOWNED; 925100966Siwasaki TAILQ_INIT(&m->mtx_blocked); 926100966Siwasaki 927100966Siwasaki LOCK_LOG_INIT(lock, opts); 928100966Siwasaki 929100966Siwasaki WITNESS_INIT(lock); 930100966Siwasaki} 931100966Siwasaki 932100966Siwasaki/* 933100966Siwasaki * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be 934100966Siwasaki * passed in as a flag here because if the corresponding mtx_init() was 935100966Siwasaki * called with MTX_QUIET set, then it will already be set in the mutex's 936100966Siwasaki * flags. 937100966Siwasaki */ 938100966Siwasakivoid 939100966Siwasakimtx_destroy(struct mtx *m) 940100966Siwasaki{ 941100966Siwasaki 942100966Siwasaki LOCK_LOG_DESTROY(&m->mtx_object, 0); 943100966Siwasaki 944100966Siwasaki if (!mtx_owned(m)) 945100966Siwasaki MPASS(mtx_unowned(m)); 946100966Siwasaki else { 947100966Siwasaki MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); 948100966Siwasaki 949100966Siwasaki /* Tell witness this isn't locked to make it happy. */ 950100966Siwasaki WITNESS_UNLOCK(&m->mtx_object, LOP_EXCLUSIVE, __FILE__, 951100966Siwasaki __LINE__); 952100966Siwasaki } 953100966Siwasaki 954100966Siwasaki WITNESS_DESTROY(&m->mtx_object); 955100966Siwasaki} 956100966Siwasaki 957100966Siwasaki/* 958100966Siwasaki * Intialize the mutex code and system mutexes. This is called from the MD 959100966Siwasaki * startup code prior to mi_startup(). The per-CPU data space needs to be 960100966Siwasaki * setup before this is called. 961100966Siwasaki */ 962100966Siwasakivoid 963100966Siwasakimutex_init(void) 964100966Siwasaki{ 965100966Siwasaki 966100966Siwasaki /* Setup thread0 so that mutexes work. */ 967100966Siwasaki LIST_INIT(&thread0.td_contested); 968100966Siwasaki 969100966Siwasaki /* 970100966Siwasaki * Initialize mutexes. 971100966Siwasaki */ 972100966Siwasaki mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); 973100966Siwasaki mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE); 974100966Siwasaki mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); 975100966Siwasaki mtx_lock(&Giant); 976100966Siwasaki} 977100966Siwasaki 978100966Siwasaki/* 979100966Siwasaki * Encapsulated Giant mutex routines. These routines provide encapsulation 980151937Sjkim * control for the Giant mutex, allowing sysctls to be used to turn on and 981151937Sjkim * off Giant around certain subsystems. The default value for the sysctls 982151937Sjkim * are set to what developers believe is stable and working in regards to 983151937Sjkim * the Giant pushdown. Developers should not turn off Giant via these 984100966Siwasaki * sysctls unless they know what they are doing. 985100966Siwasaki * 986100966Siwasaki * Callers of mtx_lock_giant() are expected to pass the return value to an 987100966Siwasaki * accompanying mtx_unlock_giant() later on. If multiple subsystems are 988100966Siwasaki * effected by a Giant wrap, all related sysctl variables must be zero for 989100966Siwasaki * the subsystem call to operate without Giant (as determined by the caller). 990100966Siwasaki */ 991100966Siwasaki 992100966SiwasakiSYSCTL_NODE(_kern, OID_AUTO, giant, CTLFLAG_RD, NULL, "Giant mutex manipulation"); 993100966Siwasaki 994100966Siwasakistatic int kern_giant_all = 0; 995100966SiwasakiSYSCTL_INT(_kern_giant, OID_AUTO, all, CTLFLAG_RW, &kern_giant_all, 0, ""); 996100966Siwasaki 997100966Siwasakiint kern_giant_proc = 1; /* Giant around PROC locks */ 998100966Siwasakiint kern_giant_file = 1; /* Giant around struct file & filedesc */ 999100966Siwasakiint kern_giant_ucred = 1; /* Giant around ucred */ 1000100966SiwasakiSYSCTL_INT(_kern_giant, OID_AUTO, proc, CTLFLAG_RW, &kern_giant_proc, 0, ""); 1001100966SiwasakiSYSCTL_INT(_kern_giant, OID_AUTO, file, CTLFLAG_RW, &kern_giant_file, 0, ""); 1002100966SiwasakiSYSCTL_INT(_kern_giant, OID_AUTO, ucred, CTLFLAG_RW, &kern_giant_ucred, 0, ""); 1003100966Siwasaki 1004100966Siwasakiint 1005100966Siwasakimtx_lock_giant(int sysctlvar) 1006100966Siwasaki{ 1007100966Siwasaki if (sysctlvar || kern_giant_all) { 1008100966Siwasaki mtx_lock(&Giant); 1009100966Siwasaki return(1); 1010100966Siwasaki } 1011100966Siwasaki return(0); 1012100966Siwasaki} 1013100966Siwasaki 1014100966Siwasakivoid 1015100966Siwasakimtx_unlock_giant(int s) 1016100966Siwasaki{ 1017100966Siwasaki if (s) 1018100966Siwasaki mtx_unlock(&Giant); 1019100966Siwasaki} 1020100966Siwasaki 1021100966Siwasaki