1 /* 2 * Copyright (c) 2005 David Xu <davidxu@freebsd.org> 3 * Copyright (C) 2003 Daniel M. Eischen <deischen@freebsd.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice unmodified, this list of conditions, and the following 11 * disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $DragonFly: src/lib/libthread_xu/thread/thr_list.c,v 1.1 2005/02/01 12:38:27 davidxu Exp $ 28 */ 29 30 #include <sys/cdefs.h> 31 #include <sys/types.h> 32 #include <sys/queue.h> 33 34 #include <stdlib.h> 35 #include <string.h> 36 #include <pthread.h> 37 38 #include "thr_private.h" 39 #include "libc_private.h" 40 41 /*#define DEBUG_THREAD_LIST */ 42 #ifdef DEBUG_THREAD_LIST 43 #define DBG_MSG stdout_debug 44 #else 45 #define DBG_MSG(x...) 46 #endif 47 48 /* 49 * Define a high water mark for the maximum number of threads that 50 * will be cached. Once this level is reached, any extra threads 51 * will be free()'d. 52 */ 53 #define MAX_CACHED_THREADS 100 54 55 /* 56 * We've got to keep track of everything that is allocated, not only 57 * to have a speedy free list, but also so they can be deallocated 58 * after a fork(). 59 */ 60 static TAILQ_HEAD(, pthread) free_threadq; 61 static umtx_t free_thread_lock; 62 static umtx_t tcb_lock; 63 static int free_thread_count = 0; 64 static int inited = 0; 65 static u_int64_t next_uniqueid = 1; 66 67 LIST_HEAD(thread_hash_head, pthread); 68 #define HASH_QUEUES 128 69 static struct thread_hash_head thr_hashtable[HASH_QUEUES]; 70 #define THREAD_HASH(thrd) (((unsigned long)thrd >> 12) % HASH_QUEUES) 71 72 static void thr_destroy(struct pthread *curthread, struct pthread *thread); 73 74 void 75 _thr_list_init(void) 76 { 77 int i; 78 79 _gc_count = 0; 80 _thr_umtx_init(&_thr_list_lock); 81 TAILQ_INIT(&_thread_list); 82 TAILQ_INIT(&free_threadq); 83 _thr_umtx_init(&free_thread_lock); 84 _thr_umtx_init(&tcb_lock); 85 if (inited) { 86 for (i = 0; i < HASH_QUEUES; ++i) 87 LIST_INIT(&thr_hashtable[i]); 88 } 89 inited = 1; 90 } 91 92 void 93 _thr_gc(struct pthread *curthread) 94 { 95 struct pthread *td, *td_next; 96 TAILQ_HEAD(, pthread) worklist; 97 98 TAILQ_INIT(&worklist); 99 THREAD_LIST_LOCK(curthread); 100 101 /* Check the threads waiting for GC. */ 102 for (td = TAILQ_FIRST(&_thread_gc_list); td != NULL; td = td_next) { 103 td_next = TAILQ_NEXT(td, gcle); 104 if (td->terminated == 0) { 105 /* make sure we are not still in userland */ 106 continue; 107 } 108 _thr_stack_free(&td->attr); 109 if (((td->tlflags & TLFLAGS_DETACHED) != 0) && 110 (td->refcount == 0)) { 111 THR_GCLIST_REMOVE(td); 112 /* 113 * The thread has detached and is no longer 114 * referenced. It is safe to remove all 115 * remnants of the thread. 116 */ 117 THR_LIST_REMOVE(td); 118 TAILQ_INSERT_HEAD(&worklist, td, gcle); 119 } 120 } 121 THREAD_LIST_UNLOCK(curthread); 122 123 while ((td = TAILQ_FIRST(&worklist)) != NULL) { 124 TAILQ_REMOVE(&worklist, td, gcle); 125 /* 126 * XXX we don't free initial thread, because there might 127 * have some code referencing initial thread. 128 */ 129 if (td == _thr_initial) { 130 DBG_MSG("Initial thread won't be freed\n"); 131 continue; 132 } 133 134 DBG_MSG("Freeing thread %p\n", td); 135 _thr_free(curthread, td); 136 } 137 } 138 139 struct pthread * 140 _thr_alloc(struct pthread *curthread) 141 { 142 struct pthread *thread = NULL; 143 struct tcb *tcb = NULL; 144 145 if (curthread != NULL) { 146 if (GC_NEEDED()) 147 _thr_gc(curthread); 148 if (free_thread_count > 0) { 149 THR_LOCK_ACQUIRE(curthread, &free_thread_lock); 150 if ((thread = TAILQ_FIRST(&free_threadq)) != NULL) { 151 TAILQ_REMOVE(&free_threadq, thread, tle); 152 tcb = thread->tcb; 153 free_thread_count--; 154 } 155 THR_LOCK_RELEASE(curthread, &free_thread_lock); 156 } 157 } 158 if ((thread == NULL) && 159 ((thread = malloc(sizeof(struct pthread))) != NULL)) { 160 if (curthread) { 161 THR_LOCK_ACQUIRE(curthread, &tcb_lock); 162 tcb = _tcb_ctor(thread, 0 /* not initial tls */); 163 THR_LOCK_RELEASE(curthread, &tcb_lock); 164 } else { 165 tcb = _tcb_ctor(thread, 1 /* initial tls */); 166 } 167 if (tcb == NULL) { 168 free(thread); 169 thread = NULL; 170 } 171 } 172 if (thread) { 173 memset(thread, 0, sizeof(*thread)); 174 thread->tcb = tcb; 175 } 176 return (thread); 177 } 178 179 void 180 _thr_free(struct pthread *curthread, struct pthread *thread) 181 { 182 DBG_MSG("Freeing thread %p\n", thread); 183 if (thread->name) { 184 free(thread->name); 185 thread->name = NULL; 186 } 187 if ((curthread == NULL) || (free_thread_count >= MAX_CACHED_THREADS)) { 188 thr_destroy(curthread, thread); 189 } else { 190 /* Add the thread to the free thread list. */ 191 THR_LOCK_ACQUIRE(curthread, &free_thread_lock); 192 TAILQ_INSERT_TAIL(&free_threadq, thread, tle); 193 free_thread_count++; 194 THR_LOCK_RELEASE(curthread, &free_thread_lock); 195 } 196 } 197 198 static void 199 thr_destroy(struct pthread *curthread, struct pthread *thread) 200 { 201 if (curthread) { 202 THR_LOCK_ACQUIRE(curthread, &tcb_lock); 203 _tcb_dtor(thread->tcb); 204 THR_LOCK_RELEASE(curthread, &tcb_lock); 205 } else { 206 _tcb_dtor(thread->tcb); 207 } 208 free(thread); 209 } 210 211 /* 212 * Add an active thread: 213 * 214 * o Assign the thread a unique id (which GDB uses to track 215 * threads. 216 * o Add the thread to the list of all threads and increment 217 * number of active threads. 218 */ 219 void 220 _thr_link(struct pthread *curthread, struct pthread *thread) 221 { 222 THREAD_LIST_LOCK(curthread); 223 /* 224 * Initialize the unique id (which GDB uses to track 225 * threads), add the thread to the list of all threads, 226 * and 227 */ 228 thread->uniqueid = next_uniqueid++; 229 THR_LIST_ADD(thread); 230 if (thread->attr.flags & PTHREAD_DETACHED) 231 thread->tlflags |= TLFLAGS_DETACHED; 232 _thread_active_threads++; 233 THREAD_LIST_UNLOCK(curthread); 234 } 235 236 /* 237 * Remove an active thread. 238 */ 239 void 240 _thr_unlink(struct pthread *curthread, struct pthread *thread) 241 { 242 THREAD_LIST_LOCK(curthread); 243 THR_LIST_REMOVE(thread); 244 _thread_active_threads--; 245 THREAD_LIST_UNLOCK(curthread); 246 } 247 248 void 249 _thr_hash_add(struct pthread *thread) 250 { 251 struct thread_hash_head *head; 252 253 head = &thr_hashtable[THREAD_HASH(thread)]; 254 LIST_INSERT_HEAD(head, thread, hle); 255 } 256 257 void 258 _thr_hash_remove(struct pthread *thread) 259 { 260 LIST_REMOVE(thread, hle); 261 } 262 263 struct pthread * 264 _thr_hash_find(struct pthread *thread) 265 { 266 struct pthread *td; 267 struct thread_hash_head *head; 268 269 head = &thr_hashtable[THREAD_HASH(thread)]; 270 LIST_FOREACH(td, head, hle) { 271 if (td == thread) 272 return (thread); 273 } 274 return (NULL); 275 } 276 277 /* 278 * Find a thread in the linked list of active threads and add a reference 279 * to it. Threads with positive reference counts will not be deallocated 280 * until all references are released. 281 */ 282 int 283 _thr_ref_add(struct pthread *curthread, struct pthread *thread, 284 int include_dead) 285 { 286 int ret; 287 288 if (thread == NULL) 289 /* Invalid thread: */ 290 return (EINVAL); 291 292 THREAD_LIST_LOCK(curthread); 293 if ((ret = _thr_find_thread(curthread, thread, include_dead)) == 0) { 294 thread->refcount++; 295 } 296 THREAD_LIST_UNLOCK(curthread); 297 298 /* Return zero if the thread exists: */ 299 return (ret); 300 } 301 302 void 303 _thr_ref_delete(struct pthread *curthread, struct pthread *thread) 304 { 305 if (thread != NULL) { 306 THREAD_LIST_LOCK(curthread); 307 thread->refcount--; 308 if ((thread->refcount == 0) && 309 (thread->tlflags & TLFLAGS_GC_SAFE) != 0) 310 THR_GCLIST_ADD(thread); 311 THREAD_LIST_UNLOCK(curthread); 312 } 313 } 314 315 int 316 _thr_find_thread(struct pthread *curthread, struct pthread *thread, 317 int include_dead) 318 { 319 struct pthread *pthread; 320 321 if (thread == NULL) 322 /* Invalid thread: */ 323 return (EINVAL); 324 325 pthread = _thr_hash_find(thread); 326 if (pthread) { 327 if (include_dead == 0 && pthread->state == PS_DEAD) { 328 pthread = NULL; 329 } 330 } 331 332 /* Return zero if the thread exists: */ 333 return ((pthread != NULL) ? 0 : ESRCH); 334 } 335