thr_list.c revision 216641
1251877Speter/* 2251877Speter * Copyright (c) 2005 David Xu <davidxu@freebsd.org> 3251877Speter * Copyright (C) 2003 Daniel M. Eischen <deischen@freebsd.org> 4251877Speter * All rights reserved. 5251877Speter * 6251877Speter * Redistribution and use in source and binary forms, with or without 7251877Speter * modification, are permitted provided that the following conditions 8251877Speter * are met: 9251877Speter * 1. Redistributions of source code must retain the above copyright 10251877Speter * notice unmodified, this list of conditions, and the following 11251877Speter * disclaimer. 12251877Speter * 2. Redistributions in binary form must reproduce the above copyright 13251877Speter * notice, this list of conditions and the following disclaimer in the 14251877Speter * documentation and/or other materials provided with the distribution. 15251877Speter * 16251877Speter * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17251877Speter * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18251877Speter * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19251877Speter * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20251877Speter * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21251877Speter * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22251877Speter * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23251877Speter * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24251877Speter * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25251877Speter * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26251877Speter * 27251877Speter * $FreeBSD: head/lib/libthr/thread/thr_list.c 216641 2010-12-22 05:01:52Z davidxu $ 28251877Speter */ 29251877Speter 30251877Speter#include <sys/types.h> 31251877Speter#include <sys/queue.h> 32251877Speter 33251877Speter#include <stdlib.h> 34251877Speter#include <string.h> 35251877Speter#include <pthread.h> 36251877Speter 37251877Speter#include "thr_private.h" 38251877Speter#include "libc_private.h" 39251877Speter 40251877Speter/*#define DEBUG_THREAD_LIST */ 41251877Speter#ifdef DEBUG_THREAD_LIST 42251877Speter#define DBG_MSG stdout_debug 43251877Speter#else 44251877Speter#define DBG_MSG(x...) 45251877Speter#endif 46251877Speter 47251877Speter#define MAX_THREADS 100000 48251877Speter 49251877Speter/* 50251877Speter * Define a high water mark for the maximum number of threads that 51251877Speter * will be cached. Once this level is reached, any extra threads 52251877Speter * will be free()'d. 53251877Speter */ 54251877Speter#define MAX_CACHED_THREADS 100 55251877Speter 56251877Speter/* 57251877Speter * We've got to keep track of everything that is allocated, not only 58251877Speter * to have a speedy free list, but also so they can be deallocated 59251877Speter * after a fork(). 60251877Speter */ 61251877Speterstatic TAILQ_HEAD(, pthread) free_threadq; 62251877Speterstatic struct umutex free_thread_lock = DEFAULT_UMUTEX; 63251877Speterstatic struct umutex tcb_lock = DEFAULT_UMUTEX; 64251877Speterstatic int free_thread_count = 0; 65251877Speterstatic int inited = 0; 66251877Speterstatic int total_threads; 67251877Speter 68251877SpeterLIST_HEAD(thread_hash_head, pthread); 69251877Speter#define HASH_QUEUES 128 70251877Speterstatic struct thread_hash_head thr_hashtable[HASH_QUEUES]; 71251877Speter#define THREAD_HASH(thrd) (((unsigned long)thrd >> 8) % HASH_QUEUES) 72251877Speter 73251877Speterstatic void thr_destroy(struct pthread *curthread, struct pthread *thread); 74251877Speter 75251877Spetervoid 76251877Speter_thr_list_init(void) 77251877Speter{ 78251877Speter int i; 79251877Speter 80251877Speter _gc_count = 0; 81251877Speter total_threads = 1; 82251877Speter _thr_urwlock_init(&_thr_list_lock); 83251877Speter TAILQ_INIT(&_thread_list); 84251877Speter TAILQ_INIT(&free_threadq); 85251877Speter _thr_umutex_init(&free_thread_lock); 86251877Speter _thr_umutex_init(&tcb_lock); 87251877Speter if (inited) { 88251877Speter for (i = 0; i < HASH_QUEUES; ++i) 89251877Speter LIST_INIT(&thr_hashtable[i]); 90251877Speter } 91251877Speter inited = 1; 92251877Speter} 93251877Speter 94251877Spetervoid 95251877Speter_thr_gc(struct pthread *curthread) 96251877Speter{ 97251877Speter struct pthread *td, *td_next; 98251877Speter TAILQ_HEAD(, pthread) worklist; 99251877Speter 100251877Speter TAILQ_INIT(&worklist); 101251877Speter THREAD_LIST_WRLOCK(curthread); 102251877Speter 103251877Speter /* Check the threads waiting for GC. */ 104251877Speter TAILQ_FOREACH_SAFE(td, &_thread_gc_list, gcle, td_next) { 105251877Speter if (td->tid != TID_TERMINATED) { 106251877Speter /* make sure we are not still in userland */ 107251877Speter continue; 108251877Speter } 109251877Speter _thr_stack_free(&td->attr); 110251877Speter THR_GCLIST_REMOVE(td); 111251877Speter TAILQ_INSERT_HEAD(&worklist, td, gcle); 112251877Speter } 113251877Speter THREAD_LIST_UNLOCK(curthread); 114251877Speter 115251877Speter while ((td = TAILQ_FIRST(&worklist)) != NULL) { 116251877Speter TAILQ_REMOVE(&worklist, td, gcle); 117251877Speter /* 118251877Speter * XXX we don't free initial thread, because there might 119251877Speter * have some code referencing initial thread. 120251877Speter */ 121251877Speter if (td == _thr_initial) { 122251877Speter DBG_MSG("Initial thread won't be freed\n"); 123251877Speter continue; 124251877Speter } 125251877Speter 126251877Speter _thr_free(curthread, td); 127251877Speter } 128251877Speter} 129251877Speter 130251877Speterstruct pthread * 131251877Speter_thr_alloc(struct pthread *curthread) 132251877Speter{ 133251877Speter struct pthread *thread = NULL; 134251877Speter struct tcb *tcb; 135251877Speter 136251877Speter if (curthread != NULL) { 137251877Speter if (GC_NEEDED()) 138251877Speter _thr_gc(curthread); 139251877Speter if (free_thread_count > 0) { 140251877Speter THR_LOCK_ACQUIRE(curthread, &free_thread_lock); 141251877Speter if ((thread = TAILQ_FIRST(&free_threadq)) != NULL) { 142251877Speter TAILQ_REMOVE(&free_threadq, thread, tle); 143251877Speter free_thread_count--; 144251877Speter } 145251877Speter THR_LOCK_RELEASE(curthread, &free_thread_lock); 146251877Speter } 147251877Speter } 148251877Speter if (thread == NULL) { 149251877Speter if (total_threads > MAX_THREADS) 150251877Speter return (NULL); 151253895Speter atomic_fetchadd_int(&total_threads, 1); 152253895Speter thread = malloc(sizeof(struct pthread)); 153253895Speter if (thread == NULL) { 154253895Speter atomic_fetchadd_int(&total_threads, -1); 155253895Speter return (NULL); 156253895Speter } 157253895Speter } 158253895Speter if (curthread != NULL) { 159251877Speter THR_LOCK_ACQUIRE(curthread, &tcb_lock); 160251877Speter tcb = _tcb_ctor(thread, 0 /* not initial tls */); 161251877Speter THR_LOCK_RELEASE(curthread, &tcb_lock); 162251877Speter } else { 163251877Speter tcb = _tcb_ctor(thread, 1 /* initial tls */); 164251877Speter } 165251877Speter if (tcb != NULL) { 166251877Speter memset(thread, 0, sizeof(*thread)); 167251877Speter thread->tcb = tcb; 168251877Speter thread->sleepqueue = _sleepq_alloc(); 169251877Speter thread->wake_addr = _thr_alloc_wake_addr(); 170251877Speter } else { 171251877Speter thr_destroy(curthread, thread); 172251877Speter atomic_fetchadd_int(&total_threads, -1); 173251877Speter thread = NULL; 174251877Speter } 175251877Speter return (thread); 176251877Speter} 177251877Speter 178251877Spetervoid 179251877Speter_thr_free(struct pthread *curthread, struct pthread *thread) 180251877Speter{ 181251877Speter DBG_MSG("Freeing thread %p\n", thread); 182251877Speter 183251877Speter /* 184251877Speter * Always free tcb, as we only know it is part of RTLD TLS 185251877Speter * block, but don't know its detail and can not assume how 186251877Speter * it works, so better to avoid caching it here. 187251877Speter */ 188251877Speter if (curthread != NULL) { 189251877Speter THR_LOCK_ACQUIRE(curthread, &tcb_lock); 190251877Speter _tcb_dtor(thread->tcb); 191251877Speter THR_LOCK_RELEASE(curthread, &tcb_lock); 192251877Speter } else { 193251877Speter _tcb_dtor(thread->tcb); 194251877Speter } 195251877Speter thread->tcb = NULL; 196251877Speter if ((curthread == NULL) || (free_thread_count >= MAX_CACHED_THREADS)) { 197251877Speter _sleepq_free(thread->sleepqueue); 198251877Speter _thr_release_wake_addr(thread->wake_addr); 199251877Speter thr_destroy(curthread, thread); 200251877Speter atomic_fetchadd_int(&total_threads, -1); 201251877Speter } else { 202251877Speter /* 203251877Speter * Add the thread to the free thread list, this also avoids 204251877Speter * pthread id is reused too quickly, may help some buggy apps. 205251877Speter */ 206251877Speter THR_LOCK_ACQUIRE(curthread, &free_thread_lock); 207251877Speter TAILQ_INSERT_TAIL(&free_threadq, thread, tle); 208251877Speter free_thread_count++; 209251877Speter THR_LOCK_RELEASE(curthread, &free_thread_lock); 210251877Speter } 211251877Speter} 212251877Speter 213251877Speterstatic void 214251877Speterthr_destroy(struct pthread *curthread __unused, struct pthread *thread) 215251877Speter{ 216251877Speter free(thread); 217251877Speter} 218251877Speter 219251877Speter/* 220251877Speter * Add the thread to the list of all threads and increment 221251877Speter * number of active threads. 222251877Speter */ 223251877Spetervoid 224251877Speter_thr_link(struct pthread *curthread, struct pthread *thread) 225251877Speter{ 226251877Speter THREAD_LIST_WRLOCK(curthread); 227251877Speter THR_LIST_ADD(thread); 228251877Speter THREAD_LIST_UNLOCK(curthread); 229251877Speter atomic_add_int(&_thread_active_threads, 1); 230251877Speter} 231251877Speter 232251877Speter/* 233251877Speter * Remove an active thread. 234251877Speter */ 235251877Spetervoid 236251877Speter_thr_unlink(struct pthread *curthread, struct pthread *thread) 237251877Speter{ 238251877Speter THREAD_LIST_WRLOCK(curthread); 239251877Speter THR_LIST_REMOVE(thread); 240251877Speter THREAD_LIST_UNLOCK(curthread); 241251877Speter atomic_add_int(&_thread_active_threads, -1); 242251877Speter} 243251877Speter 244251877Spetervoid 245251877Speter_thr_hash_add(struct pthread *thread) 246251877Speter{ 247251877Speter struct thread_hash_head *head; 248251877Speter 249251877Speter head = &thr_hashtable[THREAD_HASH(thread)]; 250251877Speter LIST_INSERT_HEAD(head, thread, hle); 251251877Speter} 252251877Speter 253251877Spetervoid 254251877Speter_thr_hash_remove(struct pthread *thread) 255251877Speter{ 256251877Speter LIST_REMOVE(thread, hle); 257251877Speter} 258251877Speter 259251877Speterstruct pthread * 260251877Speter_thr_hash_find(struct pthread *thread) 261251877Speter{ 262251877Speter struct pthread *td; 263251877Speter struct thread_hash_head *head; 264251877Speter 265251877Speter head = &thr_hashtable[THREAD_HASH(thread)]; 266251877Speter LIST_FOREACH(td, head, hle) { 267251877Speter if (td == thread) 268251877Speter return (thread); 269251877Speter } 270251877Speter return (NULL); 271251877Speter} 272251877Speter 273251877Speter/* 274251877Speter * Find a thread in the linked list of active threads and add a reference 275251877Speter * to it. Threads with positive reference counts will not be deallocated 276251877Speter * until all references are released. 277251877Speter */ 278251877Speterint 279251877Speter_thr_ref_add(struct pthread *curthread, struct pthread *thread, 280251877Speter int include_dead) 281251877Speter{ 282251877Speter int ret; 283251877Speter 284251877Speter if (thread == NULL) 285251877Speter /* Invalid thread: */ 286251877Speter return (EINVAL); 287251877Speter 288251877Speter if ((ret = _thr_find_thread(curthread, thread, include_dead)) == 0) { 289251877Speter thread->refcount++; 290251877Speter THR_CRITICAL_ENTER(curthread); 291251877Speter THR_THREAD_UNLOCK(curthread, thread); 292251877Speter } 293251877Speter 294251877Speter /* Return zero if the thread exists: */ 295 return (ret); 296} 297 298void 299_thr_ref_delete(struct pthread *curthread, struct pthread *thread) 300{ 301 THR_THREAD_LOCK(curthread, thread); 302 thread->refcount--; 303 _thr_try_gc(curthread, thread); 304 THR_CRITICAL_LEAVE(curthread); 305} 306 307/* entered with thread lock held, exit with thread lock released */ 308void 309_thr_try_gc(struct pthread *curthread, struct pthread *thread) 310{ 311 if (THR_SHOULD_GC(thread)) { 312 THR_REF_ADD(curthread, thread); 313 THR_THREAD_UNLOCK(curthread, thread); 314 THREAD_LIST_WRLOCK(curthread); 315 THR_THREAD_LOCK(curthread, thread); 316 THR_REF_DEL(curthread, thread); 317 if (THR_SHOULD_GC(thread)) { 318 THR_LIST_REMOVE(thread); 319 THR_GCLIST_ADD(thread); 320 } 321 THR_THREAD_UNLOCK(curthread, thread); 322 THREAD_LIST_UNLOCK(curthread); 323 } else { 324 THR_THREAD_UNLOCK(curthread, thread); 325 } 326} 327 328/* return with thread lock held if thread is found */ 329int 330_thr_find_thread(struct pthread *curthread, struct pthread *thread, 331 int include_dead) 332{ 333 struct pthread *pthread; 334 int ret; 335 336 if (thread == NULL) 337 return (EINVAL); 338 339 ret = 0; 340 THREAD_LIST_RDLOCK(curthread); 341 pthread = _thr_hash_find(thread); 342 if (pthread) { 343 THR_THREAD_LOCK(curthread, pthread); 344 if (include_dead == 0 && pthread->state == PS_DEAD) { 345 THR_THREAD_UNLOCK(curthread, pthread); 346 ret = ESRCH; 347 } 348 } else { 349 ret = ESRCH; 350 } 351 THREAD_LIST_UNLOCK(curthread); 352 return (ret); 353} 354