1/* $OpenLDAP$ */ 2/* This work is part of OpenLDAP Software <http://www.openldap.org/>. 3 * 4 * Copyright 1998-2011 The OpenLDAP Foundation. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted only as authorized by the OpenLDAP 9 * Public License. 10 * 11 * A copy of this license is available in file LICENSE in the 12 * top-level directory of the distribution or, alternatively, at 13 * <http://www.OpenLDAP.org/license.html>. 14 */ 15 16#include "portable.h" 17 18#include <stdio.h> 19 20#include <ac/signal.h> 21#include <ac/stdarg.h> 22#include <ac/stdlib.h> 23#include <ac/string.h> 24#include <ac/time.h> 25#include <ac/errno.h> 26 27#include "ldap-int.h" 28#include "ldap_pvt_thread.h" /* Get the thread interface */ 29#include "ldap_queue.h" 30#define LDAP_THREAD_POOL_IMPLEMENTATION 31#include "ldap_thr_debug.h" /* May rename symbols defined below */ 32 33#ifndef LDAP_THREAD_HAVE_TPOOL 34 35/* Thread-specific key with data and optional free function */ 36typedef struct ldap_int_tpool_key_s { 37 void *ltk_key; 38 void *ltk_data; 39 ldap_pvt_thread_pool_keyfree_t *ltk_free; 40} ldap_int_tpool_key_t; 41 42/* Max number of thread-specific keys we store per thread. 43 * We don't expect to use many... 44 */ 45#define MAXKEYS 32 46 47/* Max number of threads */ 48#define LDAP_MAXTHR 1024 /* must be a power of 2 */ 49 50/* (Theoretical) max number of pending requests */ 51#define MAX_PENDING (INT_MAX/2) /* INT_MAX - (room to avoid overflow) */ 52 53/* Context: thread ID and thread-specific key/data pairs */ 54typedef struct ldap_int_thread_userctx_s { 55 ldap_pvt_thread_t ltu_id; 56 ldap_int_tpool_key_t ltu_key[MAXKEYS]; 57} ldap_int_thread_userctx_t; 58 59 60/* Simple {thread ID -> context} hash table; key=ctx->ltu_id. 61 * Protected by ldap_pvt_thread_pool_mutex except during pauses, 62 * when it is read-only (used by pool_purgekey and pool_context). 63 * Protected by tpool->ltp_mutex during pauses. 64 */ 65static struct { 66 ldap_int_thread_userctx_t *ctx; 67 /* ctx is valid when not NULL or DELETED_THREAD_CTX */ 68# define DELETED_THREAD_CTX (&ldap_int_main_thrctx + 1) /* dummy addr */ 69} thread_keys[LDAP_MAXTHR]; 70 71#define TID_HASH(tid, hash) do { \ 72 unsigned const char *ptr_ = (unsigned const char *)&(tid); \ 73 unsigned i_; \ 74 for (i_ = 0, (hash) = ptr_[0]; ++i_ < sizeof(tid);) \ 75 (hash) += ((hash) << 5) ^ ptr_[i_]; \ 76} while(0) 77 78 79/* Task for a thread to perform */ 80typedef struct ldap_int_thread_task_s { 81 union { 82 LDAP_STAILQ_ENTRY(ldap_int_thread_task_s) q; 83 LDAP_SLIST_ENTRY(ldap_int_thread_task_s) l; 84 } ltt_next; 85 ldap_pvt_thread_start_t *ltt_start_routine; 86 void *ltt_arg; 87} ldap_int_thread_task_t; 88 89typedef LDAP_STAILQ_HEAD(tcq, ldap_int_thread_task_s) ldap_int_tpool_plist_t; 90 91struct ldap_int_thread_pool_s { 92 LDAP_STAILQ_ENTRY(ldap_int_thread_pool_s) ltp_next; 93 94 /* protect members below, and protect thread_keys[] during pauses */ 95 ldap_pvt_thread_mutex_t ltp_mutex; 96 97 /* not paused and something to do for pool_<wrapper/pause/destroy>() */ 98 ldap_pvt_thread_cond_t ltp_cond; 99 100 /* ltp_active_count <= 1 && ltp_pause */ 101 ldap_pvt_thread_cond_t ltp_pcond; 102 103 /* ltp_pause == 0 ? <p_pending_list : &empty_pending_list, 104 * maintaned to reduce work for pool_wrapper() 105 */ 106 ldap_int_tpool_plist_t *ltp_work_list; 107 108 /* pending tasks, and unused task objects */ 109 ldap_int_tpool_plist_t ltp_pending_list; 110 LDAP_SLIST_HEAD(tcl, ldap_int_thread_task_s) ltp_free_list; 111 112 /* The pool is finishing, waiting for its threads to close. 113 * They close when ltp_pending_list is done. pool_submit() 114 * rejects new tasks. ltp_max_pending = -(its old value). 115 */ 116 int ltp_finishing; 117 118 /* Some active task needs to be the sole active task. 119 * Atomic variable so ldap_pvt_thread_pool_pausing() can read it. 120 * Note: Pauses adjust ltp_<open_count/vary_open_count/work_list>, 121 * so pool_<submit/wrapper>() mostly can avoid testing ltp_pause. 122 */ 123 volatile sig_atomic_t ltp_pause; 124 125 /* Max number of threads in pool, or 0 for default (LDAP_MAXTHR) */ 126 int ltp_max_count; 127 128 /* Max number of pending + paused requests, negated when ltp_finishing */ 129 int ltp_max_pending; 130 131 int ltp_pending_count; /* Pending or paused requests */ 132 int ltp_active_count; /* Active, not paused requests */ 133 int ltp_open_count; /* Number of threads, negated when ltp_pause */ 134 int ltp_starting; /* Currenlty starting threads */ 135 136 /* >0 if paused or we may open a thread, <0 if we should close a thread. 137 * Updated when ltp_<finishing/pause/max_count/open_count> change. 138 * Maintained to reduce the time ltp_mutex must be locked in 139 * ldap_pvt_thread_pool_<submit/wrapper>(). 140 */ 141 int ltp_vary_open_count; 142# define SET_VARY_OPEN_COUNT(pool) \ 143 ((pool)->ltp_vary_open_count = \ 144 (pool)->ltp_pause ? 1 : \ 145 (pool)->ltp_finishing ? -1 : \ 146 ((pool)->ltp_max_count ? (pool)->ltp_max_count : LDAP_MAXTHR) \ 147 - (pool)->ltp_open_count) 148}; 149 150static ldap_int_tpool_plist_t empty_pending_list = 151 LDAP_STAILQ_HEAD_INITIALIZER(empty_pending_list); 152 153static int ldap_int_has_thread_pool = 0; 154static LDAP_STAILQ_HEAD(tpq, ldap_int_thread_pool_s) 155 ldap_int_thread_pool_list = 156 LDAP_STAILQ_HEAD_INITIALIZER(ldap_int_thread_pool_list); 157 158static ldap_pvt_thread_mutex_t ldap_pvt_thread_pool_mutex; 159 160static void *ldap_int_thread_pool_wrapper( void *pool ); 161 162static ldap_pvt_thread_key_t ldap_tpool_key; 163 164/* Context of the main thread */ 165static ldap_int_thread_userctx_t ldap_int_main_thrctx; 166 167int 168ldap_int_thread_pool_startup ( void ) 169{ 170 ldap_int_main_thrctx.ltu_id = ldap_pvt_thread_self(); 171 ldap_pvt_thread_key_create( &ldap_tpool_key ); 172 return ldap_pvt_thread_mutex_init(&ldap_pvt_thread_pool_mutex); 173} 174 175int 176ldap_int_thread_pool_shutdown ( void ) 177{ 178 struct ldap_int_thread_pool_s *pool; 179 180 while ((pool = LDAP_STAILQ_FIRST(&ldap_int_thread_pool_list)) != NULL) { 181 (ldap_pvt_thread_pool_destroy)(&pool, 0); /* ignore thr_debug macro */ 182 } 183 ldap_pvt_thread_mutex_destroy(&ldap_pvt_thread_pool_mutex); 184 ldap_pvt_thread_key_destroy( ldap_tpool_key ); 185 return(0); 186} 187 188 189/* Create a thread pool */ 190int 191ldap_pvt_thread_pool_init ( 192 ldap_pvt_thread_pool_t *tpool, 193 int max_threads, 194 int max_pending ) 195{ 196 ldap_pvt_thread_pool_t pool; 197 int rc; 198 199 /* multiple pools are currently not supported (ITS#4943) */ 200 assert(!ldap_int_has_thread_pool); 201 202 if (! (0 <= max_threads && max_threads <= LDAP_MAXTHR)) 203 max_threads = 0; 204 if (! (1 <= max_pending && max_pending <= MAX_PENDING)) 205 max_pending = MAX_PENDING; 206 207 *tpool = NULL; 208 pool = (ldap_pvt_thread_pool_t) LDAP_CALLOC(1, 209 sizeof(struct ldap_int_thread_pool_s)); 210 211 if (pool == NULL) return(-1); 212 213 rc = ldap_pvt_thread_mutex_init(&pool->ltp_mutex); 214 if (rc != 0) 215 return(rc); 216 rc = ldap_pvt_thread_cond_init(&pool->ltp_cond); 217 if (rc != 0) 218 return(rc); 219 rc = ldap_pvt_thread_cond_init(&pool->ltp_pcond); 220 if (rc != 0) 221 return(rc); 222 223 ldap_int_has_thread_pool = 1; 224 225 pool->ltp_max_count = max_threads; 226 SET_VARY_OPEN_COUNT(pool); 227 pool->ltp_max_pending = max_pending; 228 229 LDAP_STAILQ_INIT(&pool->ltp_pending_list); 230 pool->ltp_work_list = &pool->ltp_pending_list; 231 LDAP_SLIST_INIT(&pool->ltp_free_list); 232 233 ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex); 234 LDAP_STAILQ_INSERT_TAIL(&ldap_int_thread_pool_list, pool, ltp_next); 235 ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex); 236 237 /* Start no threads just yet. That can break if the process forks 238 * later, as slapd does in order to daemonize. On at least POSIX, 239 * only the forking thread would survive in the child. Yet fork() 240 * can't unlock/clean up other threads' locks and data structures, 241 * unless pthread_atfork() handlers have been set up to do so. 242 */ 243 244 *tpool = pool; 245 return(0); 246} 247 248 249/* Submit a task to be performed by the thread pool */ 250int 251ldap_pvt_thread_pool_submit ( 252 ldap_pvt_thread_pool_t *tpool, 253 ldap_pvt_thread_start_t *start_routine, void *arg ) 254{ 255 struct ldap_int_thread_pool_s *pool; 256 ldap_int_thread_task_t *task; 257 ldap_pvt_thread_t thr; 258 259 if (tpool == NULL) 260 return(-1); 261 262 pool = *tpool; 263 264 if (pool == NULL) 265 return(-1); 266 267 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex); 268 269 if (pool->ltp_pending_count >= pool->ltp_max_pending) 270 goto failed; 271 272 task = LDAP_SLIST_FIRST(&pool->ltp_free_list); 273 if (task) { 274 LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltt_next.l); 275 } else { 276 task = (ldap_int_thread_task_t *) LDAP_MALLOC(sizeof(*task)); 277 if (task == NULL) 278 goto failed; 279 } 280 281 task->ltt_start_routine = start_routine; 282 task->ltt_arg = arg; 283 284 pool->ltp_pending_count++; 285 LDAP_STAILQ_INSERT_TAIL(&pool->ltp_pending_list, task, ltt_next.q); 286 287 /* true if ltp_pause != 0 or we should open (create) a thread */ 288 if (pool->ltp_vary_open_count > 0 && 289 pool->ltp_open_count < pool->ltp_active_count+pool->ltp_pending_count) 290 { 291 if (pool->ltp_pause) 292 goto done; 293 294 pool->ltp_starting++; 295 pool->ltp_open_count++; 296 SET_VARY_OPEN_COUNT(pool); 297 298 if (0 != ldap_pvt_thread_create( 299 &thr, 1, ldap_int_thread_pool_wrapper, pool)) 300 { 301 /* couldn't create thread. back out of 302 * ltp_open_count and check for even worse things. 303 */ 304 pool->ltp_starting--; 305 pool->ltp_open_count--; 306 SET_VARY_OPEN_COUNT(pool); 307 308 if (pool->ltp_open_count == 0) { 309 /* no open threads at all?!? 310 */ 311 ldap_int_thread_task_t *ptr; 312 313 /* let pool_destroy know there are no more threads */ 314 ldap_pvt_thread_cond_signal(&pool->ltp_cond); 315 316 LDAP_STAILQ_FOREACH(ptr, &pool->ltp_pending_list, ltt_next.q) 317 if (ptr == task) break; 318 if (ptr == task) { 319 /* no open threads, task not handled, so 320 * back out of ltp_pending_count, free the task, 321 * report the error. 322 */ 323 pool->ltp_pending_count--; 324 LDAP_STAILQ_REMOVE(&pool->ltp_pending_list, task, 325 ldap_int_thread_task_s, ltt_next.q); 326 LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, task, 327 ltt_next.l); 328 goto failed; 329 } 330 } 331 /* there is another open thread, so this 332 * task will be handled eventually. 333 */ 334 } 335 } 336 ldap_pvt_thread_cond_signal(&pool->ltp_cond); 337 338 done: 339 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex); 340 return(0); 341 342 failed: 343 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex); 344 return(-1); 345} 346 347static void * 348no_task( void *ctx, void *arg ) 349{ 350 return NULL; 351} 352 353/* Cancel a pending task that was previously submitted. 354 * Return 1 if the task was successfully cancelled, 0 if 355 * not found, -1 for invalid parameters 356 */ 357int 358ldap_pvt_thread_pool_retract ( 359 ldap_pvt_thread_pool_t *tpool, 360 ldap_pvt_thread_start_t *start_routine, void *arg ) 361{ 362 struct ldap_int_thread_pool_s *pool; 363 ldap_int_thread_task_t *task; 364 365 if (tpool == NULL) 366 return(-1); 367 368 pool = *tpool; 369 370 if (pool == NULL) 371 return(-1); 372 373 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex); 374 LDAP_STAILQ_FOREACH(task, &pool->ltp_pending_list, ltt_next.q) 375 if (task->ltt_start_routine == start_routine && 376 task->ltt_arg == arg) { 377 /* Could LDAP_STAILQ_REMOVE the task, but that 378 * walks ltp_pending_list again to find it. 379 */ 380 task->ltt_start_routine = no_task; 381 task->ltt_arg = NULL; 382 break; 383 } 384 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex); 385 return task != NULL; 386} 387 388/* Set max #threads. value <= 0 means max supported #threads (LDAP_MAXTHR) */ 389int 390ldap_pvt_thread_pool_maxthreads( 391 ldap_pvt_thread_pool_t *tpool, 392 int max_threads ) 393{ 394 struct ldap_int_thread_pool_s *pool; 395 396 if (! (0 <= max_threads && max_threads <= LDAP_MAXTHR)) 397 max_threads = 0; 398 399 if (tpool == NULL) 400 return(-1); 401 402 pool = *tpool; 403 404 if (pool == NULL) 405 return(-1); 406 407 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex); 408 409 pool->ltp_max_count = max_threads; 410 SET_VARY_OPEN_COUNT(pool); 411 412 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex); 413 return(0); 414} 415 416/* Inspect the pool */ 417int 418ldap_pvt_thread_pool_query( 419 ldap_pvt_thread_pool_t *tpool, 420 ldap_pvt_thread_pool_param_t param, 421 void *value ) 422{ 423 struct ldap_int_thread_pool_s *pool; 424 int count = -1; 425 426 if ( tpool == NULL || value == NULL ) { 427 return -1; 428 } 429 430 pool = *tpool; 431 432 if ( pool == NULL ) { 433 return 0; 434 } 435 436 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex); 437 switch ( param ) { 438 case LDAP_PVT_THREAD_POOL_PARAM_MAX: 439 count = pool->ltp_max_count; 440 break; 441 442 case LDAP_PVT_THREAD_POOL_PARAM_MAX_PENDING: 443 count = pool->ltp_max_pending; 444 if (count < 0) 445 count = -count; 446 if (count == MAX_PENDING) 447 count = 0; 448 break; 449 450 case LDAP_PVT_THREAD_POOL_PARAM_OPEN: 451 count = pool->ltp_open_count; 452 if (count < 0) 453 count = -count; 454 break; 455 456 case LDAP_PVT_THREAD_POOL_PARAM_STARTING: 457 count = pool->ltp_starting; 458 break; 459 460 case LDAP_PVT_THREAD_POOL_PARAM_ACTIVE: 461 count = pool->ltp_active_count; 462 break; 463 464 case LDAP_PVT_THREAD_POOL_PARAM_PAUSING: 465 count = pool->ltp_pause; 466 break; 467 468 case LDAP_PVT_THREAD_POOL_PARAM_PENDING: 469 count = pool->ltp_pending_count; 470 break; 471 472 case LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD: 473 count = pool->ltp_pending_count + pool->ltp_active_count; 474 break; 475 476 case LDAP_PVT_THREAD_POOL_PARAM_ACTIVE_MAX: 477 break; 478 479 case LDAP_PVT_THREAD_POOL_PARAM_PENDING_MAX: 480 break; 481 482 case LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD_MAX: 483 break; 484 485 case LDAP_PVT_THREAD_POOL_PARAM_STATE: 486 *((char **)value) = 487 pool->ltp_pause ? "pausing" : 488 !pool->ltp_finishing ? "running" : 489 pool->ltp_pending_count ? "finishing" : "stopping"; 490 break; 491 492 case LDAP_PVT_THREAD_POOL_PARAM_UNKNOWN: 493 break; 494 } 495 ldap_pvt_thread_mutex_unlock( &pool->ltp_mutex ); 496 497 if ( count > -1 ) { 498 *((int *)value) = count; 499 } 500 501 return ( count == -1 ? -1 : 0 ); 502} 503 504/* 505 * true if pool is pausing; does not lock any mutex to check. 506 * 0 if not pause, 1 if pause, -1 if error or no pool. 507 */ 508int 509ldap_pvt_thread_pool_pausing( ldap_pvt_thread_pool_t *tpool ) 510{ 511 int rc = -1; 512 struct ldap_int_thread_pool_s *pool; 513 514 if ( tpool != NULL && (pool = *tpool) != NULL ) { 515 rc = pool->ltp_pause; 516 } 517 518 return rc; 519} 520 521/* 522 * wrapper for ldap_pvt_thread_pool_query(), left around 523 * for backwards compatibility 524 */ 525int 526ldap_pvt_thread_pool_backload ( ldap_pvt_thread_pool_t *tpool ) 527{ 528 int rc, count; 529 530 rc = ldap_pvt_thread_pool_query( tpool, 531 LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD, (void *)&count ); 532 533 if ( rc == 0 ) { 534 return count; 535 } 536 537 return rc; 538} 539 540/* Destroy the pool after making its threads finish */ 541int 542ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending ) 543{ 544 struct ldap_int_thread_pool_s *pool, *pptr; 545 ldap_int_thread_task_t *task; 546 547 if (tpool == NULL) 548 return(-1); 549 550 pool = *tpool; 551 552 if (pool == NULL) return(-1); 553 554 ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex); 555 LDAP_STAILQ_FOREACH(pptr, &ldap_int_thread_pool_list, ltp_next) 556 if (pptr == pool) break; 557 if (pptr == pool) 558 LDAP_STAILQ_REMOVE(&ldap_int_thread_pool_list, pool, 559 ldap_int_thread_pool_s, ltp_next); 560 ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex); 561 562 if (pool != pptr) return(-1); 563 564 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex); 565 566 pool->ltp_finishing = 1; 567 SET_VARY_OPEN_COUNT(pool); 568 if (pool->ltp_max_pending > 0) 569 pool->ltp_max_pending = -pool->ltp_max_pending; 570 571 if (!run_pending) { 572 while ((task = LDAP_STAILQ_FIRST(&pool->ltp_pending_list)) != NULL) { 573 LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltt_next.q); 574 LDAP_FREE(task); 575 } 576 pool->ltp_pending_count = 0; 577 } 578 579 while (pool->ltp_open_count) { 580 if (!pool->ltp_pause) 581 ldap_pvt_thread_cond_broadcast(&pool->ltp_cond); 582 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex); 583 } 584 585 while ((task = LDAP_SLIST_FIRST(&pool->ltp_free_list)) != NULL) 586 { 587 LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltt_next.l); 588 LDAP_FREE(task); 589 } 590 591 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex); 592 ldap_pvt_thread_cond_destroy(&pool->ltp_pcond); 593 ldap_pvt_thread_cond_destroy(&pool->ltp_cond); 594 ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex); 595 LDAP_FREE(pool); 596 *tpool = NULL; 597 ldap_int_has_thread_pool = 0; 598 return(0); 599} 600 601/* Thread loop. Accept and handle submitted tasks. */ 602static void * 603ldap_int_thread_pool_wrapper ( 604 void *xpool ) 605{ 606 struct ldap_int_thread_pool_s *pool = xpool; 607 ldap_int_thread_task_t *task; 608 ldap_int_tpool_plist_t *work_list; 609 ldap_int_thread_userctx_t ctx, *kctx; 610 unsigned i, keyslot, hash; 611 612 assert(pool != NULL); 613 614 for ( i=0; i<MAXKEYS; i++ ) { 615 ctx.ltu_key[i].ltk_key = NULL; 616 } 617 618 ctx.ltu_id = ldap_pvt_thread_self(); 619 TID_HASH(ctx.ltu_id, hash); 620 621 ldap_pvt_thread_key_setdata( ldap_tpool_key, &ctx ); 622 623 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex); 624 625 /* thread_keys[] is read-only when paused */ 626 while (pool->ltp_pause) 627 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex); 628 629 /* find a key slot to give this thread ID and store a 630 * pointer to our keys there; start at the thread ID 631 * itself (mod LDAP_MAXTHR) and look for an empty slot. 632 */ 633 ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex); 634 for (keyslot = hash & (LDAP_MAXTHR-1); 635 (kctx = thread_keys[keyslot].ctx) && kctx != DELETED_THREAD_CTX; 636 keyslot = (keyslot+1) & (LDAP_MAXTHR-1)); 637 thread_keys[keyslot].ctx = &ctx; 638 ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex); 639 640 pool->ltp_starting--; 641 pool->ltp_active_count++; 642 643 for (;;) { 644 work_list = pool->ltp_work_list; /* help the compiler a bit */ 645 task = LDAP_STAILQ_FIRST(work_list); 646 if (task == NULL) { /* paused or no pending tasks */ 647 if (--(pool->ltp_active_count) < 2) { 648 /* Notify pool_pause it is the sole active thread. */ 649 ldap_pvt_thread_cond_signal(&pool->ltp_pcond); 650 } 651 652 do { 653 if (pool->ltp_vary_open_count < 0) { 654 /* Not paused, and either finishing or too many 655 * threads running (can happen if ltp_max_count 656 * was reduced). Let this thread die. 657 */ 658 goto done; 659 } 660 661 /* We could check an idle timer here, and let the 662 * thread die if it has been inactive for a while. 663 * Only die if there are other open threads (i.e., 664 * always have at least one thread open). 665 * The check should be like this: 666 * if (pool->ltp_open_count>1 && pool->ltp_starting==0) 667 * check timer, wait if ltp_pause, leave thread; 668 * 669 * Just use pthread_cond_timedwait() if we want to 670 * check idle time. 671 */ 672 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex); 673 674 work_list = pool->ltp_work_list; 675 task = LDAP_STAILQ_FIRST(work_list); 676 } while (task == NULL); 677 678 pool->ltp_active_count++; 679 } 680 681 LDAP_STAILQ_REMOVE_HEAD(work_list, ltt_next.q); 682 pool->ltp_pending_count--; 683 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex); 684 685 task->ltt_start_routine(&ctx, task->ltt_arg); 686 687 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex); 688 LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, task, ltt_next.l); 689 } 690 done: 691 692 assert(!pool->ltp_pause); /* thread_keys writable, ltp_open_count >= 0 */ 693 694 /* The ltp_mutex lock protects ctx->ltu_key from pool_purgekey() 695 * during this call, since it prevents new pauses. */ 696 ldap_pvt_thread_pool_context_reset(&ctx); 697 698 ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex); 699 thread_keys[keyslot].ctx = DELETED_THREAD_CTX; 700 ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex); 701 702 pool->ltp_open_count--; 703 SET_VARY_OPEN_COUNT(pool); 704 /* let pool_destroy know we're all done */ 705 if (pool->ltp_open_count == 0) 706 ldap_pvt_thread_cond_signal(&pool->ltp_cond); 707 708 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex); 709 710 ldap_pvt_thread_exit(NULL); 711 return(NULL); 712} 713 714static int 715handle_pause( ldap_pvt_thread_pool_t *tpool, int do_pause ) 716{ 717 struct ldap_int_thread_pool_s *pool; 718 719 if (tpool == NULL) 720 return(-1); 721 722 pool = *tpool; 723 724 if (pool == NULL) 725 return(0); 726 727 if (! (do_pause || pool->ltp_pause)) 728 return(0); 729 730 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex); 731 732 /* If someone else has already requested a pause, we have to wait */ 733 if (pool->ltp_pause) { 734 pool->ltp_pending_count++; 735 pool->ltp_active_count--; 736 /* let the other pool_pause() know when it can proceed */ 737 if (pool->ltp_active_count < 2) 738 ldap_pvt_thread_cond_signal(&pool->ltp_pcond); 739 do { 740 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex); 741 } while (pool->ltp_pause); 742 pool->ltp_pending_count--; 743 pool->ltp_active_count++; 744 } 745 746 if (do_pause) { 747 /* Wait for everyone else to pause or finish */ 748 pool->ltp_pause = 1; 749 /* Let ldap_pvt_thread_pool_submit() through to its ltp_pause test, 750 * and do not finish threads in ldap_pvt_thread_pool_wrapper() */ 751 pool->ltp_open_count = -pool->ltp_open_count; 752 SET_VARY_OPEN_COUNT(pool); 753 /* Hide pending tasks from ldap_pvt_thread_pool_wrapper() */ 754 pool->ltp_work_list = &empty_pending_list; 755 756 while (pool->ltp_active_count > 1) { 757 ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex); 758 } 759 } 760 761 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex); 762 return(!do_pause); 763} 764 765/* 766 * If a pause was requested, wait for it. If several threads 767 * are waiting to pause, let through one or more pauses. 768 * Return 1 if we waited, 0 if not, -1 at parameter error. 769 */ 770int 771ldap_pvt_thread_pool_pausecheck( ldap_pvt_thread_pool_t *tpool ) 772{ 773 return handle_pause( tpool, 0 ); 774} 775 776/* Pause the pool. Return when all other threads are paused. */ 777int 778ldap_pvt_thread_pool_pause( ldap_pvt_thread_pool_t *tpool ) 779{ 780 return handle_pause( tpool, 1 ); 781} 782 783/* End a pause */ 784int 785ldap_pvt_thread_pool_resume ( 786 ldap_pvt_thread_pool_t *tpool ) 787{ 788 struct ldap_int_thread_pool_s *pool; 789 790 if (tpool == NULL) 791 return(-1); 792 793 pool = *tpool; 794 795 if (pool == NULL) 796 return(0); 797 798 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex); 799 800 assert(pool->ltp_pause); 801 pool->ltp_pause = 0; 802 if (pool->ltp_open_count <= 0) /* true when paused, but be paranoid */ 803 pool->ltp_open_count = -pool->ltp_open_count; 804 SET_VARY_OPEN_COUNT(pool); 805 pool->ltp_work_list = &pool->ltp_pending_list; 806 807 ldap_pvt_thread_cond_broadcast(&pool->ltp_cond); 808 809 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex); 810 return(0); 811} 812 813/* 814 * Get the key's data and optionally free function in the given context. 815 */ 816int ldap_pvt_thread_pool_getkey( 817 void *xctx, 818 void *key, 819 void **data, 820 ldap_pvt_thread_pool_keyfree_t **kfree ) 821{ 822 ldap_int_thread_userctx_t *ctx = xctx; 823 int i; 824 825 if ( !ctx || !key || !data ) return EINVAL; 826 827 for ( i=0; i<MAXKEYS && ctx->ltu_key[i].ltk_key; i++ ) { 828 if ( ctx->ltu_key[i].ltk_key == key ) { 829 *data = ctx->ltu_key[i].ltk_data; 830 if ( kfree ) *kfree = ctx->ltu_key[i].ltk_free; 831 return 0; 832 } 833 } 834 return ENOENT; 835} 836 837static void 838clear_key_idx( ldap_int_thread_userctx_t *ctx, int i ) 839{ 840 for ( ; i < MAXKEYS-1 && ctx->ltu_key[i+1].ltk_key; i++ ) 841 ctx->ltu_key[i] = ctx->ltu_key[i+1]; 842 ctx->ltu_key[i].ltk_key = NULL; 843} 844 845/* 846 * Set or remove data for the key in the given context. 847 * key can be any unique pointer. 848 * kfree() is an optional function to free the data (but not the key): 849 * pool_context_reset() and pool_purgekey() call kfree(key, data), 850 * but pool_setkey() does not. For pool_setkey() it is the caller's 851 * responsibility to free any existing data with the same key. 852 * kfree() must not call functions taking a tpool argument. 853 */ 854int ldap_pvt_thread_pool_setkey( 855 void *xctx, 856 void *key, 857 void *data, 858 ldap_pvt_thread_pool_keyfree_t *kfree, 859 void **olddatap, 860 ldap_pvt_thread_pool_keyfree_t **oldkfreep ) 861{ 862 ldap_int_thread_userctx_t *ctx = xctx; 863 int i, found; 864 865 if ( !ctx || !key ) return EINVAL; 866 867 for ( i=found=0; i<MAXKEYS; i++ ) { 868 if ( ctx->ltu_key[i].ltk_key == key ) { 869 found = 1; 870 break; 871 } else if ( !ctx->ltu_key[i].ltk_key ) { 872 break; 873 } 874 } 875 876 if ( olddatap ) { 877 if ( found ) { 878 *olddatap = ctx->ltu_key[i].ltk_data; 879 } else { 880 *olddatap = NULL; 881 } 882 } 883 884 if ( oldkfreep ) { 885 if ( found ) { 886 *oldkfreep = ctx->ltu_key[i].ltk_free; 887 } else { 888 *oldkfreep = 0; 889 } 890 } 891 892 if ( data || kfree ) { 893 if ( i>=MAXKEYS ) 894 return ENOMEM; 895 ctx->ltu_key[i].ltk_key = key; 896 ctx->ltu_key[i].ltk_data = data; 897 ctx->ltu_key[i].ltk_free = kfree; 898 } else if ( found ) { 899 clear_key_idx( ctx, i ); 900 } 901 902 return 0; 903} 904 905/* Free all elements with this key, no matter which thread they're in. 906 * May only be called while the pool is paused. 907 */ 908void ldap_pvt_thread_pool_purgekey( void *key ) 909{ 910 int i, j; 911 ldap_int_thread_userctx_t *ctx; 912 913 assert ( key != NULL ); 914 915 for ( i=0; i<LDAP_MAXTHR; i++ ) { 916 ctx = thread_keys[i].ctx; 917 if ( ctx && ctx != DELETED_THREAD_CTX ) { 918 for ( j=0; j<MAXKEYS && ctx->ltu_key[j].ltk_key; j++ ) { 919 if ( ctx->ltu_key[j].ltk_key == key ) { 920 if (ctx->ltu_key[j].ltk_free) 921 ctx->ltu_key[j].ltk_free( ctx->ltu_key[j].ltk_key, 922 ctx->ltu_key[j].ltk_data ); 923 clear_key_idx( ctx, j ); 924 break; 925 } 926 } 927 } 928 } 929} 930 931/* 932 * Find the context of the current thread. 933 * This is necessary if the caller does not have access to the 934 * thread context handle (for example, a slapd plugin calling 935 * slapi_search_internal()). No doubt it is more efficient 936 * for the application to keep track of the thread context 937 * handles itself. 938 */ 939void *ldap_pvt_thread_pool_context( ) 940{ 941 void *ctx = NULL; 942 943 ldap_pvt_thread_key_getdata( ldap_tpool_key, &ctx ); 944 return ctx ? ctx : (void *) &ldap_int_main_thrctx; 945} 946 947/* 948 * Free the context's keys. 949 * Must not call functions taking a tpool argument (because this 950 * thread already holds ltp_mutex when called from pool_wrapper()). 951 */ 952void ldap_pvt_thread_pool_context_reset( void *vctx ) 953{ 954 ldap_int_thread_userctx_t *ctx = vctx; 955 int i; 956 957 for ( i=MAXKEYS-1; i>=0; i--) { 958 if ( !ctx->ltu_key[i].ltk_key ) 959 continue; 960 if ( ctx->ltu_key[i].ltk_free ) 961 ctx->ltu_key[i].ltk_free( ctx->ltu_key[i].ltk_key, 962 ctx->ltu_key[i].ltk_data ); 963 ctx->ltu_key[i].ltk_key = NULL; 964 } 965} 966 967ldap_pvt_thread_t ldap_pvt_thread_pool_tid( void *vctx ) 968{ 969 ldap_int_thread_userctx_t *ctx = vctx; 970 971 return ctx->ltu_id; 972} 973#endif /* LDAP_THREAD_HAVE_TPOOL */ 974