txg.c revision 251631
166830Sobrien/* 266830Sobrien * CDDL HEADER START 366830Sobrien * 466830Sobrien * The contents of this file are subject to the terms of the 566830Sobrien * Common Development and Distribution License (the "License"). 666830Sobrien * You may not use this file except in compliance with the License. 766830Sobrien * 866830Sobrien * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 966830Sobrien * or http://www.opensolaris.org/os/licensing. 1066830Sobrien * See the License for the specific language governing permissions 1166830Sobrien * and limitations under the License. 1266830Sobrien * 1366830Sobrien * When distributing Covered Code, include this CDDL HEADER in each 1466830Sobrien * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 1566830Sobrien * If applicable, add the following below this CDDL HEADER, with the 1666830Sobrien * fields enclosed by brackets "[]" replaced with your own identifying 1766830Sobrien * information: Portions Copyright [yyyy] [name of copyright owner] 1866830Sobrien * 1966830Sobrien * CDDL HEADER END 2066830Sobrien */ 2166830Sobrien/* 2266830Sobrien * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 2366830Sobrien * Portions Copyright 2011 Martin Matuska <mm@FreeBSD.org> 2466830Sobrien * Copyright (c) 2013 by Delphix. All rights reserved. 25100280Sgordon */ 2651231Ssheldonh 2766830Sobrien#include <sys/zfs_context.h> 2866830Sobrien#include <sys/txg_impl.h> 2943803Sdillon#include <sys/dmu_impl.h> 30127345Sbrooks#include <sys/dmu_tx.h> 31240336Sobrien#include <sys/dsl_pool.h> 32136224Smtm#include <sys/dsl_scan.h> 3375931Simp#include <sys/callb.h> 34127345Sbrooks 3576409Sbsd/* 36127345Sbrooks * ZFS Transaction Groups 37174464Sdougb * ---------------------- 3876409Sbsd * 39127345Sbrooks * ZFS transaction groups are, as the name implies, groups of transactions 4043803Sdillon * that act on persistent state. ZFS asserts consistency at the granularity of 41108191Sdillon * these transaction groups. Each successive transaction group (txg) is 42108191Sdillon * assigned a 64-bit consecutive identifier. There are three active 43108191Sdillon * transaction group states: open, quiescing, or syncing. At any given time, 44225670Shrs * there may be an active txg associated with each state; each active txg may 45225670Shrs * either be processing, or blocked waiting to enter the next state. There may 46225670Shrs * be up to three active txgs, and there is always a txg in the open state 47127345Sbrooks * (though it may be blocked waiting to enter the quiescing state). In broad 48225670Shrs * strokes, transactions ��� operations that change in-memory structures ��� are 49127345Sbrooks * accepted into the txg in the open state, and are completed while the txg is 50127345Sbrooks * in the open or quiescing states. The accumulated changes are written to 51170198Sdougb * disk in the syncing state. 52170198Sdougb * 53225670Shrs * Open 54170198Sdougb * 55225670Shrs * When a new txg becomes active, it first enters the open state. New 56108191Sdillon * transactions ��� updates to in-memory structures ��� are assigned to the 57108191Sdillon * currently open txg. There is always a txg in the open state so that ZFS can 58 * accept new changes (though the txg may refuse new changes if it has hit 59 * some limit). ZFS advances the open txg to the next state for a variety of 60 * reasons such as it hitting a time or size threshold, or the execution of an 61 * administrative action that must be completed in the syncing state. 62 * 63 * Quiescing 64 * 65 * After a txg exits the open state, it enters the quiescing state. The 66 * quiescing state is intended to provide a buffer between accepting new 67 * transactions in the open state and writing them out to stable storage in 68 * the syncing state. While quiescing, transactions can continue their 69 * operation without delaying either of the other states. Typically, a txg is 70 * in the quiescing state very briefly since the operations are bounded by 71 * software latencies rather than, say, slower I/O latencies. After all 72 * transactions complete, the txg is ready to enter the next state. 73 * 74 * Syncing 75 * 76 * In the syncing state, the in-memory state built up during the open and (to 77 * a lesser degree) the quiescing states is written to stable storage. The 78 * process of writing out modified data can, in turn modify more data. For 79 * example when we write new blocks, we need to allocate space for them; those 80 * allocations modify metadata (space maps)... which themselves must be 81 * written to stable storage. During the sync state, ZFS iterates, writing out 82 * data until it converges and all in-memory changes have been written out. 83 * The first such pass is the largest as it encompasses all the modified user 84 * data (as opposed to filesystem metadata). Subsequent passes typically have 85 * far less data to write as they consist exclusively of filesystem metadata. 86 * 87 * To ensure convergence, after a certain number of passes ZFS begins 88 * overwriting locations on stable storage that had been allocated earlier in 89 * the syncing state (and subsequently freed). ZFS usually allocates new 90 * blocks to optimize for large, continuous, writes. For the syncing state to 91 * converge however it must complete a pass where no new blocks are allocated 92 * since each allocation requires a modification of persistent metadata. 93 * Further, to hasten convergence, after a prescribed number of passes, ZFS 94 * also defers frees, and stops compressing. 95 * 96 * In addition to writing out user data, we must also execute synctasks during 97 * the syncing context. A synctask is the mechanism by which some 98 * administrative activities work such as creating and destroying snapshots or 99 * datasets. Note that when a synctask is initiated it enters the open txg, 100 * and ZFS then pushes that txg as quickly as possible to completion of the 101 * syncing state in order to reduce the latency of the administrative 102 * activity. To complete the syncing state, ZFS writes out a new uberblock, 103 * the root of the tree of blocks that comprise all state stored on the ZFS 104 * pool. Finally, if there is a quiesced txg waiting, we signal that it can 105 * now transition to the syncing state. 106 */ 107 108static void txg_sync_thread(void *arg); 109static void txg_quiesce_thread(void *arg); 110 111int zfs_txg_timeout = 5; /* max seconds worth of delta per txg */ 112 113SYSCTL_DECL(_vfs_zfs); 114SYSCTL_NODE(_vfs_zfs, OID_AUTO, txg, CTLFLAG_RW, 0, "ZFS TXG"); 115TUNABLE_INT("vfs.zfs.txg.timeout", &zfs_txg_timeout); 116SYSCTL_INT(_vfs_zfs_txg, OID_AUTO, timeout, CTLFLAG_RW, &zfs_txg_timeout, 0, 117 "Maximum seconds worth of delta per txg"); 118 119/* 120 * Prepare the txg subsystem. 121 */ 122void 123txg_init(dsl_pool_t *dp, uint64_t txg) 124{ 125 tx_state_t *tx = &dp->dp_tx; 126 int c; 127 bzero(tx, sizeof (tx_state_t)); 128 129 tx->tx_cpu = kmem_zalloc(max_ncpus * sizeof (tx_cpu_t), KM_SLEEP); 130 131 for (c = 0; c < max_ncpus; c++) { 132 int i; 133 134 mutex_init(&tx->tx_cpu[c].tc_lock, NULL, MUTEX_DEFAULT, NULL); 135 mutex_init(&tx->tx_cpu[c].tc_open_lock, NULL, MUTEX_DEFAULT, 136 NULL); 137 for (i = 0; i < TXG_SIZE; i++) { 138 cv_init(&tx->tx_cpu[c].tc_cv[i], NULL, CV_DEFAULT, 139 NULL); 140 list_create(&tx->tx_cpu[c].tc_callbacks[i], 141 sizeof (dmu_tx_callback_t), 142 offsetof(dmu_tx_callback_t, dcb_node)); 143 } 144 } 145 146 mutex_init(&tx->tx_sync_lock, NULL, MUTEX_DEFAULT, NULL); 147 148 cv_init(&tx->tx_sync_more_cv, NULL, CV_DEFAULT, NULL); 149 cv_init(&tx->tx_sync_done_cv, NULL, CV_DEFAULT, NULL); 150 cv_init(&tx->tx_quiesce_more_cv, NULL, CV_DEFAULT, NULL); 151 cv_init(&tx->tx_quiesce_done_cv, NULL, CV_DEFAULT, NULL); 152 cv_init(&tx->tx_exit_cv, NULL, CV_DEFAULT, NULL); 153 154 tx->tx_open_txg = txg; 155} 156 157/* 158 * Close down the txg subsystem. 159 */ 160void 161txg_fini(dsl_pool_t *dp) 162{ 163 tx_state_t *tx = &dp->dp_tx; 164 int c; 165 166 ASSERT(tx->tx_threads == 0); 167 168 mutex_destroy(&tx->tx_sync_lock); 169 170 cv_destroy(&tx->tx_sync_more_cv); 171 cv_destroy(&tx->tx_sync_done_cv); 172 cv_destroy(&tx->tx_quiesce_more_cv); 173 cv_destroy(&tx->tx_quiesce_done_cv); 174 cv_destroy(&tx->tx_exit_cv); 175 176 for (c = 0; c < max_ncpus; c++) { 177 int i; 178 179 mutex_destroy(&tx->tx_cpu[c].tc_open_lock); 180 mutex_destroy(&tx->tx_cpu[c].tc_lock); 181 for (i = 0; i < TXG_SIZE; i++) { 182 cv_destroy(&tx->tx_cpu[c].tc_cv[i]); 183 list_destroy(&tx->tx_cpu[c].tc_callbacks[i]); 184 } 185 } 186 187 if (tx->tx_commit_cb_taskq != NULL) 188 taskq_destroy(tx->tx_commit_cb_taskq); 189 190 kmem_free(tx->tx_cpu, max_ncpus * sizeof (tx_cpu_t)); 191 192 bzero(tx, sizeof (tx_state_t)); 193} 194 195/* 196 * Start syncing transaction groups. 197 */ 198void 199txg_sync_start(dsl_pool_t *dp) 200{ 201 tx_state_t *tx = &dp->dp_tx; 202 203 mutex_enter(&tx->tx_sync_lock); 204 205 dprintf("pool %p\n", dp); 206 207 ASSERT(tx->tx_threads == 0); 208 209 tx->tx_threads = 2; 210 211 tx->tx_quiesce_thread = thread_create(NULL, 0, txg_quiesce_thread, 212 dp, 0, &p0, TS_RUN, minclsyspri); 213 214 /* 215 * The sync thread can need a larger-than-default stack size on 216 * 32-bit x86. This is due in part to nested pools and 217 * scrub_visitbp() recursion. 218 */ 219 tx->tx_sync_thread = thread_create(NULL, 32<<10, txg_sync_thread, 220 dp, 0, &p0, TS_RUN, minclsyspri); 221 222 mutex_exit(&tx->tx_sync_lock); 223} 224 225static void 226txg_thread_enter(tx_state_t *tx, callb_cpr_t *cpr) 227{ 228 CALLB_CPR_INIT(cpr, &tx->tx_sync_lock, callb_generic_cpr, FTAG); 229 mutex_enter(&tx->tx_sync_lock); 230} 231 232static void 233txg_thread_exit(tx_state_t *tx, callb_cpr_t *cpr, kthread_t **tpp) 234{ 235 ASSERT(*tpp != NULL); 236 *tpp = NULL; 237 tx->tx_threads--; 238 cv_broadcast(&tx->tx_exit_cv); 239 CALLB_CPR_EXIT(cpr); /* drops &tx->tx_sync_lock */ 240 thread_exit(); 241} 242 243static void 244txg_thread_wait(tx_state_t *tx, callb_cpr_t *cpr, kcondvar_t *cv, uint64_t time) 245{ 246 CALLB_CPR_SAFE_BEGIN(cpr); 247 248 if (time) 249 (void) cv_timedwait(cv, &tx->tx_sync_lock, time); 250 else 251 cv_wait(cv, &tx->tx_sync_lock); 252 253 CALLB_CPR_SAFE_END(cpr, &tx->tx_sync_lock); 254} 255 256/* 257 * Stop syncing transaction groups. 258 */ 259void 260txg_sync_stop(dsl_pool_t *dp) 261{ 262 tx_state_t *tx = &dp->dp_tx; 263 264 dprintf("pool %p\n", dp); 265 /* 266 * Finish off any work in progress. 267 */ 268 ASSERT(tx->tx_threads == 2); 269 270 /* 271 * We need to ensure that we've vacated the deferred space_maps. 272 */ 273 txg_wait_synced(dp, tx->tx_open_txg + TXG_DEFER_SIZE); 274 275 /* 276 * Wake all sync threads and wait for them to die. 277 */ 278 mutex_enter(&tx->tx_sync_lock); 279 280 ASSERT(tx->tx_threads == 2); 281 282 tx->tx_exiting = 1; 283 284 cv_broadcast(&tx->tx_quiesce_more_cv); 285 cv_broadcast(&tx->tx_quiesce_done_cv); 286 cv_broadcast(&tx->tx_sync_more_cv); 287 288 while (tx->tx_threads != 0) 289 cv_wait(&tx->tx_exit_cv, &tx->tx_sync_lock); 290 291 tx->tx_exiting = 0; 292 293 mutex_exit(&tx->tx_sync_lock); 294} 295 296uint64_t 297txg_hold_open(dsl_pool_t *dp, txg_handle_t *th) 298{ 299 tx_state_t *tx = &dp->dp_tx; 300 tx_cpu_t *tc = &tx->tx_cpu[CPU_SEQID]; 301 uint64_t txg; 302 303 mutex_enter(&tc->tc_open_lock); 304 txg = tx->tx_open_txg; 305 306 mutex_enter(&tc->tc_lock); 307 tc->tc_count[txg & TXG_MASK]++; 308 mutex_exit(&tc->tc_lock); 309 310 th->th_cpu = tc; 311 th->th_txg = txg; 312 313 return (txg); 314} 315 316void 317txg_rele_to_quiesce(txg_handle_t *th) 318{ 319 tx_cpu_t *tc = th->th_cpu; 320 321 ASSERT(!MUTEX_HELD(&tc->tc_lock)); 322 mutex_exit(&tc->tc_open_lock); 323} 324 325void 326txg_register_callbacks(txg_handle_t *th, list_t *tx_callbacks) 327{ 328 tx_cpu_t *tc = th->th_cpu; 329 int g = th->th_txg & TXG_MASK; 330 331 mutex_enter(&tc->tc_lock); 332 list_move_tail(&tc->tc_callbacks[g], tx_callbacks); 333 mutex_exit(&tc->tc_lock); 334} 335 336void 337txg_rele_to_sync(txg_handle_t *th) 338{ 339 tx_cpu_t *tc = th->th_cpu; 340 int g = th->th_txg & TXG_MASK; 341 342 mutex_enter(&tc->tc_lock); 343 ASSERT(tc->tc_count[g] != 0); 344 if (--tc->tc_count[g] == 0) 345 cv_broadcast(&tc->tc_cv[g]); 346 mutex_exit(&tc->tc_lock); 347 348 th->th_cpu = NULL; /* defensive */ 349} 350 351/* 352 * Blocks until all transactions in the group are committed. 353 * 354 * On return, the transaction group has reached a stable state in which it can 355 * then be passed off to the syncing context. 356 */ 357static void 358txg_quiesce(dsl_pool_t *dp, uint64_t txg) 359{ 360 tx_state_t *tx = &dp->dp_tx; 361 int g = txg & TXG_MASK; 362 int c; 363 364 /* 365 * Grab all tc_open_locks so nobody else can get into this txg. 366 */ 367 for (c = 0; c < max_ncpus; c++) 368 mutex_enter(&tx->tx_cpu[c].tc_open_lock); 369 370 ASSERT(txg == tx->tx_open_txg); 371 tx->tx_open_txg++; 372 373 /* 374 * Now that we've incremented tx_open_txg, we can let threads 375 * enter the next transaction group. 376 */ 377 for (c = 0; c < max_ncpus; c++) 378 mutex_exit(&tx->tx_cpu[c].tc_open_lock); 379 380 /* 381 * Quiesce the transaction group by waiting for everyone to txg_exit(). 382 */ 383 for (c = 0; c < max_ncpus; c++) { 384 tx_cpu_t *tc = &tx->tx_cpu[c]; 385 mutex_enter(&tc->tc_lock); 386 while (tc->tc_count[g] != 0) 387 cv_wait(&tc->tc_cv[g], &tc->tc_lock); 388 mutex_exit(&tc->tc_lock); 389 } 390} 391 392static void 393txg_do_callbacks(void *arg) 394{ 395 list_t *cb_list = arg; 396 397 dmu_tx_do_callbacks(cb_list, 0); 398 399 list_destroy(cb_list); 400 401 kmem_free(cb_list, sizeof (list_t)); 402} 403 404/* 405 * Dispatch the commit callbacks registered on this txg to worker threads. 406 * 407 * If no callbacks are registered for a given TXG, nothing happens. 408 * This function creates a taskq for the associated pool, if needed. 409 */ 410static void 411txg_dispatch_callbacks(dsl_pool_t *dp, uint64_t txg) 412{ 413 int c; 414 tx_state_t *tx = &dp->dp_tx; 415 list_t *cb_list; 416 417 for (c = 0; c < max_ncpus; c++) { 418 tx_cpu_t *tc = &tx->tx_cpu[c]; 419 /* 420 * No need to lock tx_cpu_t at this point, since this can 421 * only be called once a txg has been synced. 422 */ 423 424 int g = txg & TXG_MASK; 425 426 if (list_is_empty(&tc->tc_callbacks[g])) 427 continue; 428 429 if (tx->tx_commit_cb_taskq == NULL) { 430 /* 431 * Commit callback taskq hasn't been created yet. 432 */ 433 tx->tx_commit_cb_taskq = taskq_create("tx_commit_cb", 434 max_ncpus, minclsyspri, max_ncpus, max_ncpus * 2, 435 TASKQ_PREPOPULATE); 436 } 437 438 cb_list = kmem_alloc(sizeof (list_t), KM_SLEEP); 439 list_create(cb_list, sizeof (dmu_tx_callback_t), 440 offsetof(dmu_tx_callback_t, dcb_node)); 441 442 list_move_tail(&tc->tc_callbacks[g], cb_list); 443 444 (void) taskq_dispatch(tx->tx_commit_cb_taskq, (task_func_t *) 445 txg_do_callbacks, cb_list, TQ_SLEEP); 446 } 447} 448 449static void 450txg_sync_thread(void *arg) 451{ 452 dsl_pool_t *dp = arg; 453 spa_t *spa = dp->dp_spa; 454 tx_state_t *tx = &dp->dp_tx; 455 callb_cpr_t cpr; 456 uint64_t start, delta; 457 458 txg_thread_enter(tx, &cpr); 459 460 start = delta = 0; 461 for (;;) { 462 uint64_t timer, timeout = zfs_txg_timeout * hz; 463 uint64_t txg; 464 465 /* 466 * We sync when we're scanning, there's someone waiting 467 * on us, or the quiesce thread has handed off a txg to 468 * us, or we have reached our timeout. 469 */ 470 timer = (delta >= timeout ? 0 : timeout - delta); 471 while (!dsl_scan_active(dp->dp_scan) && 472 !tx->tx_exiting && timer > 0 && 473 tx->tx_synced_txg >= tx->tx_sync_txg_waiting && 474 tx->tx_quiesced_txg == 0) { 475 dprintf("waiting; tx_synced=%llu waiting=%llu dp=%p\n", 476 tx->tx_synced_txg, tx->tx_sync_txg_waiting, dp); 477 txg_thread_wait(tx, &cpr, &tx->tx_sync_more_cv, timer); 478 delta = ddi_get_lbolt() - start; 479 timer = (delta > timeout ? 0 : timeout - delta); 480 } 481 482 /* 483 * Wait until the quiesce thread hands off a txg to us, 484 * prompting it to do so if necessary. 485 */ 486 while (!tx->tx_exiting && tx->tx_quiesced_txg == 0) { 487 if (tx->tx_quiesce_txg_waiting < tx->tx_open_txg+1) 488 tx->tx_quiesce_txg_waiting = tx->tx_open_txg+1; 489 cv_broadcast(&tx->tx_quiesce_more_cv); 490 txg_thread_wait(tx, &cpr, &tx->tx_quiesce_done_cv, 0); 491 } 492 493 if (tx->tx_exiting) 494 txg_thread_exit(tx, &cpr, &tx->tx_sync_thread); 495 496 /* 497 * Consume the quiesced txg which has been handed off to 498 * us. This may cause the quiescing thread to now be 499 * able to quiesce another txg, so we must signal it. 500 */ 501 txg = tx->tx_quiesced_txg; 502 tx->tx_quiesced_txg = 0; 503 tx->tx_syncing_txg = txg; 504 cv_broadcast(&tx->tx_quiesce_more_cv); 505 506 dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", 507 txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); 508 mutex_exit(&tx->tx_sync_lock); 509 510 start = ddi_get_lbolt(); 511 spa_sync(spa, txg); 512 delta = ddi_get_lbolt() - start; 513 514 mutex_enter(&tx->tx_sync_lock); 515 tx->tx_synced_txg = txg; 516 tx->tx_syncing_txg = 0; 517 cv_broadcast(&tx->tx_sync_done_cv); 518 519 /* 520 * Dispatch commit callbacks to worker threads. 521 */ 522 txg_dispatch_callbacks(dp, txg); 523 } 524} 525 526static void 527txg_quiesce_thread(void *arg) 528{ 529 dsl_pool_t *dp = arg; 530 tx_state_t *tx = &dp->dp_tx; 531 callb_cpr_t cpr; 532 533 txg_thread_enter(tx, &cpr); 534 535 for (;;) { 536 uint64_t txg; 537 538 /* 539 * We quiesce when there's someone waiting on us. 540 * However, we can only have one txg in "quiescing" or 541 * "quiesced, waiting to sync" state. So we wait until 542 * the "quiesced, waiting to sync" txg has been consumed 543 * by the sync thread. 544 */ 545 while (!tx->tx_exiting && 546 (tx->tx_open_txg >= tx->tx_quiesce_txg_waiting || 547 tx->tx_quiesced_txg != 0)) 548 txg_thread_wait(tx, &cpr, &tx->tx_quiesce_more_cv, 0); 549 550 if (tx->tx_exiting) 551 txg_thread_exit(tx, &cpr, &tx->tx_quiesce_thread); 552 553 txg = tx->tx_open_txg; 554 dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", 555 txg, tx->tx_quiesce_txg_waiting, 556 tx->tx_sync_txg_waiting); 557 mutex_exit(&tx->tx_sync_lock); 558 txg_quiesce(dp, txg); 559 mutex_enter(&tx->tx_sync_lock); 560 561 /* 562 * Hand this txg off to the sync thread. 563 */ 564 dprintf("quiesce done, handing off txg %llu\n", txg); 565 tx->tx_quiesced_txg = txg; 566 cv_broadcast(&tx->tx_sync_more_cv); 567 cv_broadcast(&tx->tx_quiesce_done_cv); 568 } 569} 570 571/* 572 * Delay this thread by 'ticks' if we are still in the open transaction 573 * group and there is already a waiting txg quiescing or quiesced. 574 * Abort the delay if this txg stalls or enters the quiescing state. 575 */ 576void 577txg_delay(dsl_pool_t *dp, uint64_t txg, int ticks) 578{ 579 tx_state_t *tx = &dp->dp_tx; 580 clock_t timeout = ddi_get_lbolt() + ticks; 581 582 /* don't delay if this txg could transition to quiescing immediately */ 583 if (tx->tx_open_txg > txg || 584 tx->tx_syncing_txg == txg-1 || tx->tx_synced_txg == txg-1) 585 return; 586 587 mutex_enter(&tx->tx_sync_lock); 588 if (tx->tx_open_txg > txg || tx->tx_synced_txg == txg-1) { 589 mutex_exit(&tx->tx_sync_lock); 590 return; 591 } 592 593 while (ddi_get_lbolt() < timeout && 594 tx->tx_syncing_txg < txg-1 && !txg_stalled(dp)) 595 (void) cv_timedwait(&tx->tx_quiesce_more_cv, &tx->tx_sync_lock, 596 timeout - ddi_get_lbolt()); 597 598 mutex_exit(&tx->tx_sync_lock); 599} 600 601void 602txg_wait_synced(dsl_pool_t *dp, uint64_t txg) 603{ 604 tx_state_t *tx = &dp->dp_tx; 605 606 ASSERT(!dsl_pool_config_held(dp)); 607 608 mutex_enter(&tx->tx_sync_lock); 609 ASSERT(tx->tx_threads == 2); 610 if (txg == 0) 611 txg = tx->tx_open_txg + TXG_DEFER_SIZE; 612 if (tx->tx_sync_txg_waiting < txg) 613 tx->tx_sync_txg_waiting = txg; 614 dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", 615 txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); 616 while (tx->tx_synced_txg < txg) { 617 dprintf("broadcasting sync more " 618 "tx_synced=%llu waiting=%llu dp=%p\n", 619 tx->tx_synced_txg, tx->tx_sync_txg_waiting, dp); 620 cv_broadcast(&tx->tx_sync_more_cv); 621 cv_wait(&tx->tx_sync_done_cv, &tx->tx_sync_lock); 622 } 623 mutex_exit(&tx->tx_sync_lock); 624} 625 626void 627txg_wait_open(dsl_pool_t *dp, uint64_t txg) 628{ 629 tx_state_t *tx = &dp->dp_tx; 630 631 ASSERT(!dsl_pool_config_held(dp)); 632 633 mutex_enter(&tx->tx_sync_lock); 634 ASSERT(tx->tx_threads == 2); 635 if (txg == 0) 636 txg = tx->tx_open_txg + 1; 637 if (tx->tx_quiesce_txg_waiting < txg) 638 tx->tx_quiesce_txg_waiting = txg; 639 dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", 640 txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); 641 while (tx->tx_open_txg < txg) { 642 cv_broadcast(&tx->tx_quiesce_more_cv); 643 cv_wait(&tx->tx_quiesce_done_cv, &tx->tx_sync_lock); 644 } 645 mutex_exit(&tx->tx_sync_lock); 646} 647 648boolean_t 649txg_stalled(dsl_pool_t *dp) 650{ 651 tx_state_t *tx = &dp->dp_tx; 652 return (tx->tx_quiesce_txg_waiting > tx->tx_open_txg); 653} 654 655boolean_t 656txg_sync_waiting(dsl_pool_t *dp) 657{ 658 tx_state_t *tx = &dp->dp_tx; 659 660 return (tx->tx_syncing_txg <= tx->tx_sync_txg_waiting || 661 tx->tx_quiesced_txg != 0); 662} 663 664/* 665 * Per-txg object lists. 666 */ 667void 668txg_list_create(txg_list_t *tl, size_t offset) 669{ 670 int t; 671 672 mutex_init(&tl->tl_lock, NULL, MUTEX_DEFAULT, NULL); 673 674 tl->tl_offset = offset; 675 676 for (t = 0; t < TXG_SIZE; t++) 677 tl->tl_head[t] = NULL; 678} 679 680void 681txg_list_destroy(txg_list_t *tl) 682{ 683 int t; 684 685 for (t = 0; t < TXG_SIZE; t++) 686 ASSERT(txg_list_empty(tl, t)); 687 688 mutex_destroy(&tl->tl_lock); 689} 690 691boolean_t 692txg_list_empty(txg_list_t *tl, uint64_t txg) 693{ 694 return (tl->tl_head[txg & TXG_MASK] == NULL); 695} 696 697/* 698 * Add an entry to the list (unless it's already on the list). 699 * Returns B_TRUE if it was actually added. 700 */ 701boolean_t 702txg_list_add(txg_list_t *tl, void *p, uint64_t txg) 703{ 704 int t = txg & TXG_MASK; 705 txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); 706 boolean_t add; 707 708 mutex_enter(&tl->tl_lock); 709 add = (tn->tn_member[t] == 0); 710 if (add) { 711 tn->tn_member[t] = 1; 712 tn->tn_next[t] = tl->tl_head[t]; 713 tl->tl_head[t] = tn; 714 } 715 mutex_exit(&tl->tl_lock); 716 717 return (add); 718} 719 720/* 721 * Add an entry to the end of the list, unless it's already on the list. 722 * (walks list to find end) 723 * Returns B_TRUE if it was actually added. 724 */ 725boolean_t 726txg_list_add_tail(txg_list_t *tl, void *p, uint64_t txg) 727{ 728 int t = txg & TXG_MASK; 729 txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); 730 boolean_t add; 731 732 mutex_enter(&tl->tl_lock); 733 add = (tn->tn_member[t] == 0); 734 if (add) { 735 txg_node_t **tp; 736 737 for (tp = &tl->tl_head[t]; *tp != NULL; tp = &(*tp)->tn_next[t]) 738 continue; 739 740 tn->tn_member[t] = 1; 741 tn->tn_next[t] = NULL; 742 *tp = tn; 743 } 744 mutex_exit(&tl->tl_lock); 745 746 return (add); 747} 748 749/* 750 * Remove the head of the list and return it. 751 */ 752void * 753txg_list_remove(txg_list_t *tl, uint64_t txg) 754{ 755 int t = txg & TXG_MASK; 756 txg_node_t *tn; 757 void *p = NULL; 758 759 mutex_enter(&tl->tl_lock); 760 if ((tn = tl->tl_head[t]) != NULL) { 761 p = (char *)tn - tl->tl_offset; 762 tl->tl_head[t] = tn->tn_next[t]; 763 tn->tn_next[t] = NULL; 764 tn->tn_member[t] = 0; 765 } 766 mutex_exit(&tl->tl_lock); 767 768 return (p); 769} 770 771/* 772 * Remove a specific item from the list and return it. 773 */ 774void * 775txg_list_remove_this(txg_list_t *tl, void *p, uint64_t txg) 776{ 777 int t = txg & TXG_MASK; 778 txg_node_t *tn, **tp; 779 780 mutex_enter(&tl->tl_lock); 781 782 for (tp = &tl->tl_head[t]; (tn = *tp) != NULL; tp = &tn->tn_next[t]) { 783 if ((char *)tn - tl->tl_offset == p) { 784 *tp = tn->tn_next[t]; 785 tn->tn_next[t] = NULL; 786 tn->tn_member[t] = 0; 787 mutex_exit(&tl->tl_lock); 788 return (p); 789 } 790 } 791 792 mutex_exit(&tl->tl_lock); 793 794 return (NULL); 795} 796 797boolean_t 798txg_list_member(txg_list_t *tl, void *p, uint64_t txg) 799{ 800 int t = txg & TXG_MASK; 801 txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); 802 803 return (tn->tn_member[t] != 0); 804} 805 806/* 807 * Walk a txg list -- only safe if you know it's not changing. 808 */ 809void * 810txg_list_head(txg_list_t *tl, uint64_t txg) 811{ 812 int t = txg & TXG_MASK; 813 txg_node_t *tn = tl->tl_head[t]; 814 815 return (tn == NULL ? NULL : (char *)tn - tl->tl_offset); 816} 817 818void * 819txg_list_next(txg_list_t *tl, void *p, uint64_t txg) 820{ 821 int t = txg & TXG_MASK; 822 txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); 823 824 tn = tn->tn_next[t]; 825 826 return (tn == NULL ? NULL : (char *)tn - tl->tl_offset); 827} 828