4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
24 * Copyright (c) 2013 Steven Hartland. All rights reserved.
25 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
26 * Copyright 2016 Nexenta Systems, Inc. All rights reserved.
29 #include <sys/dsl_pool.h>
30 #include <sys/dsl_dataset.h>
31 #include <sys/dsl_prop.h>
32 #include <sys/dsl_dir.h>
33 #include <sys/dsl_synctask.h>
34 #include <sys/dsl_scan.h>
35 #include <sys/dnode.h>
36 #include <sys/dmu_tx.h>
37 #include <sys/dmu_objset.h>
41 #include <sys/zfs_context.h>
42 #include <sys/fs/zfs.h>
43 #include <sys/zfs_znode.h>
44 #include <sys/spa_impl.h>
45 #include <sys/dsl_deadlist.h>
46 #include <sys/vdev_impl.h>
47 #include <sys/metaslab_impl.h>
48 #include <sys/bptree.h>
49 #include <sys/zfeature.h>
50 #include <sys/zil_impl.h>
51 #include <sys/dsl_userhold.h>
52 #include <sys/trace_txg.h>
59 * ZFS must limit the rate of incoming writes to the rate at which it is able
60 * to sync data modifications to the backend storage. Throttling by too much
61 * creates an artificial limit; throttling by too little can only be sustained
62 * for short periods and would lead to highly lumpy performance. On a per-pool
63 * basis, ZFS tracks the amount of modified (dirty) data. As operations change
64 * data, the amount of dirty data increases; as ZFS syncs out data, the amount
65 * of dirty data decreases. When the amount of dirty data exceeds a
66 * predetermined threshold further modifications are blocked until the amount
67 * of dirty data decreases (as data is synced out).
69 * The limit on dirty data is tunable, and should be adjusted according to
70 * both the IO capacity and available memory of the system. The larger the
71 * window, the more ZFS is able to aggregate and amortize metadata (and data)
72 * changes. However, memory is a limited resource, and allowing for more dirty
73 * data comes at the cost of keeping other useful data in memory (for example
74 * ZFS data cached by the ARC).
78 * As buffers are modified dsl_pool_willuse_space() increments both the per-
79 * txg (dp_dirty_pertxg[]) and poolwide (dp_dirty_total) accounting of
80 * dirty space used; dsl_pool_dirty_space() decrements those values as data
81 * is synced out from dsl_pool_sync(). While only the poolwide value is
82 * relevant, the per-txg value is useful for debugging. The tunable
83 * zfs_dirty_data_max determines the dirty space limit. Once that value is
84 * exceeded, new writes are halted until space frees up.
86 * The zfs_dirty_data_sync tunable dictates the threshold at which we
87 * ensure that there is a txg syncing (see the comment in txg.c for a full
88 * description of transaction group stages).
90 * The IO scheduler uses both the dirty space limit and current amount of
91 * dirty data as inputs. Those values affect the number of concurrent IOs ZFS
92 * issues. See the comment in vdev_queue.c for details of the IO scheduler.
94 * The delay is also calculated based on the amount of dirty data. See the
95 * comment above dmu_tx_delay() for details.
99 * zfs_dirty_data_max will be set to zfs_dirty_data_max_percent% of all memory,
100 * capped at zfs_dirty_data_max_max. It can also be overridden with a module
103 unsigned long zfs_dirty_data_max = 0;
104 unsigned long zfs_dirty_data_max_max = 0;
105 int zfs_dirty_data_max_percent = 10;
106 int zfs_dirty_data_max_max_percent = 25;
109 * If there is at least this much dirty data, push out a txg.
111 unsigned long zfs_dirty_data_sync = 64 * 1024 * 1024;
114 * Once there is this amount of dirty data, the dmu_tx_delay() will kick in
115 * and delay each transaction.
116 * This value should be >= zfs_vdev_async_write_active_max_dirty_percent.
118 int zfs_delay_min_dirty_percent = 60;
121 * This controls how quickly the delay approaches infinity.
122 * Larger values cause it to delay more for a given amount of dirty data.
123 * Therefore larger values will cause there to be less dirty data for a
126 * For the smoothest delay, this value should be about 1 billion divided
127 * by the maximum number of operations per second. This will smoothly
128 * handle between 10x and 1/10th this number.
130 * Note: zfs_delay_scale * zfs_dirty_data_max must be < 2^64, due to the
131 * multiply in dmu_tx_delay().
133 unsigned long zfs_delay_scale = 1000 * 1000 * 1000 / 2000;
136 * This determines the number of threads used by the dp_sync_taskq.
138 int zfs_sync_taskq_batch_pct = 75;
141 * These tunables determine the behavior of how zil_itxg_clean() is
142 * called via zil_clean() in the context of spa_sync(). When an itxg
143 * list needs to be cleaned, TQ_NOSLEEP will be used when dispatching.
144 * If the dispatch fails, the call to zil_itxg_clean() will occur
145 * synchronously in the context of spa_sync(), which can negatively
146 * impact the performance of spa_sync() (e.g. in the case of the itxg
147 * list having a large number of itxs that needs to be cleaned).
149 * Thus, these tunables can be used to manipulate the behavior of the
150 * taskq used by zil_clean(); they determine the number of taskq entries
151 * that are pre-populated when the taskq is first created (via the
152 * "zfs_zil_clean_taskq_minalloc" tunable) and the maximum number of
153 * taskq entries that are cached after an on-demand allocation (via the
154 * "zfs_zil_clean_taskq_maxalloc").
156 * The idea being, we want to try reasonably hard to ensure there will
157 * already be a taskq entry pre-allocated by the time that it is needed
158 * by zil_clean(). This way, we can avoid the possibility of an
159 * on-demand allocation of a new taskq entry from failing, which would
160 * result in zil_itxg_clean() being called synchronously from zil_clean()
161 * (which can adversely affect performance of spa_sync()).
163 * Additionally, the number of threads used by the taskq can be
164 * configured via the "zfs_zil_clean_taskq_nthr_pct" tunable.
166 int zfs_zil_clean_taskq_nthr_pct = 100;
167 int zfs_zil_clean_taskq_minalloc = 1024;
168 int zfs_zil_clean_taskq_maxalloc = 1024 * 1024;
171 dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp)
176 err = zap_lookup(dp->dp_meta_objset,
177 dsl_dir_phys(dp->dp_root_dir)->dd_child_dir_zapobj,
178 name, sizeof (obj), 1, &obj);
182 return (dsl_dir_hold_obj(dp, obj, name, dp, ddp));
186 dsl_pool_open_impl(spa_t *spa, uint64_t txg)
189 blkptr_t *bp = spa_get_rootblkptr(spa);
191 dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP);
193 dp->dp_meta_rootbp = *bp;
194 rrw_init(&dp->dp_config_rwlock, B_TRUE);
198 txg_list_create(&dp->dp_dirty_datasets, spa,
199 offsetof(dsl_dataset_t, ds_dirty_link));
200 txg_list_create(&dp->dp_dirty_zilogs, spa,
201 offsetof(zilog_t, zl_dirty_link));
202 txg_list_create(&dp->dp_dirty_dirs, spa,
203 offsetof(dsl_dir_t, dd_dirty_link));
204 txg_list_create(&dp->dp_sync_tasks, spa,
205 offsetof(dsl_sync_task_t, dst_node));
206 txg_list_create(&dp->dp_early_sync_tasks, spa,
207 offsetof(dsl_sync_task_t, dst_node));
209 dp->dp_sync_taskq = taskq_create("dp_sync_taskq",
210 zfs_sync_taskq_batch_pct, minclsyspri, 1, INT_MAX,
211 TASKQ_THREADS_CPU_PCT);
213 dp->dp_zil_clean_taskq = taskq_create("dp_zil_clean_taskq",
214 zfs_zil_clean_taskq_nthr_pct, minclsyspri,
215 zfs_zil_clean_taskq_minalloc,
216 zfs_zil_clean_taskq_maxalloc,
217 TASKQ_PREPOPULATE | TASKQ_THREADS_CPU_PCT);
219 mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL);
220 cv_init(&dp->dp_spaceavail_cv, NULL, CV_DEFAULT, NULL);
222 dp->dp_iput_taskq = taskq_create("z_iput", max_ncpus, defclsyspri,
223 max_ncpus * 8, INT_MAX, TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
229 dsl_pool_init(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
232 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
235 * Initialize the caller's dsl_pool_t structure before we actually open
236 * the meta objset. This is done because a self-healing write zio may
237 * be issued as part of dmu_objset_open_impl() and the spa needs its
238 * dsl_pool_t initialized in order to handle the write.
242 err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp,
243 &dp->dp_meta_objset);
253 dsl_pool_open(dsl_pool_t *dp)
260 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
261 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
262 DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
263 &dp->dp_root_dir_obj);
267 err = dsl_dir_hold_obj(dp, dp->dp_root_dir_obj,
268 NULL, dp, &dp->dp_root_dir);
272 err = dsl_pool_open_special_dir(dp, MOS_DIR_NAME, &dp->dp_mos_dir);
276 if (spa_version(dp->dp_spa) >= SPA_VERSION_ORIGIN) {
277 err = dsl_pool_open_special_dir(dp, ORIGIN_DIR_NAME, &dd);
280 err = dsl_dataset_hold_obj(dp,
281 dsl_dir_phys(dd)->dd_head_dataset_obj, FTAG, &ds);
283 err = dsl_dataset_hold_obj(dp,
284 dsl_dataset_phys(ds)->ds_prev_snap_obj, dp,
285 &dp->dp_origin_snap);
286 dsl_dataset_rele(ds, FTAG);
288 dsl_dir_rele(dd, dp);
293 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
294 err = dsl_pool_open_special_dir(dp, FREE_DIR_NAME,
299 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
300 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj);
303 VERIFY0(bpobj_open(&dp->dp_free_bpobj,
304 dp->dp_meta_objset, obj));
307 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_OBSOLETE_COUNTS)) {
308 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
309 DMU_POOL_OBSOLETE_BPOBJ, sizeof (uint64_t), 1, &obj);
311 VERIFY0(bpobj_open(&dp->dp_obsolete_bpobj,
312 dp->dp_meta_objset, obj));
313 } else if (err == ENOENT) {
315 * We might not have created the remap bpobj yet.
324 * Note: errors ignored, because the these special dirs, used for
325 * space accounting, are only created on demand.
327 (void) dsl_pool_open_special_dir(dp, LEAK_DIR_NAME,
330 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
331 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
332 DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
338 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_EMPTY_BPOBJ)) {
339 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
340 DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
341 &dp->dp_empty_bpobj);
346 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
347 DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1,
348 &dp->dp_tmp_userrefs_obj);
354 err = dsl_scan_init(dp, dp->dp_tx.tx_open_txg);
357 rrw_exit(&dp->dp_config_rwlock, FTAG);
362 dsl_pool_close(dsl_pool_t *dp)
365 * Drop our references from dsl_pool_open().
367 * Since we held the origin_snap from "syncing" context (which
368 * includes pool-opening context), it actually only got a "ref"
369 * and not a hold, so just drop that here.
371 if (dp->dp_origin_snap != NULL)
372 dsl_dataset_rele(dp->dp_origin_snap, dp);
373 if (dp->dp_mos_dir != NULL)
374 dsl_dir_rele(dp->dp_mos_dir, dp);
375 if (dp->dp_free_dir != NULL)
376 dsl_dir_rele(dp->dp_free_dir, dp);
377 if (dp->dp_leak_dir != NULL)
378 dsl_dir_rele(dp->dp_leak_dir, dp);
379 if (dp->dp_root_dir != NULL)
380 dsl_dir_rele(dp->dp_root_dir, dp);
382 bpobj_close(&dp->dp_free_bpobj);
383 bpobj_close(&dp->dp_obsolete_bpobj);
385 /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
386 if (dp->dp_meta_objset != NULL)
387 dmu_objset_evict(dp->dp_meta_objset);
389 txg_list_destroy(&dp->dp_dirty_datasets);
390 txg_list_destroy(&dp->dp_dirty_zilogs);
391 txg_list_destroy(&dp->dp_sync_tasks);
392 txg_list_destroy(&dp->dp_early_sync_tasks);
393 txg_list_destroy(&dp->dp_dirty_dirs);
395 taskq_destroy(dp->dp_zil_clean_taskq);
396 taskq_destroy(dp->dp_sync_taskq);
399 * We can't set retry to TRUE since we're explicitly specifying
400 * a spa to flush. This is good enough; any missed buffers for
401 * this spa won't cause trouble, and they'll eventually fall
402 * out of the ARC just like any other unused buffer.
404 arc_flush(dp->dp_spa, FALSE);
406 mmp_fini(dp->dp_spa);
409 dmu_buf_user_evict_wait();
411 rrw_destroy(&dp->dp_config_rwlock);
412 mutex_destroy(&dp->dp_lock);
413 cv_destroy(&dp->dp_spaceavail_cv);
414 taskq_destroy(dp->dp_iput_taskq);
415 if (dp->dp_blkstats != NULL) {
416 mutex_destroy(&dp->dp_blkstats->zab_lock);
417 vmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
419 kmem_free(dp, sizeof (dsl_pool_t));
423 dsl_pool_create_obsolete_bpobj(dsl_pool_t *dp, dmu_tx_t *tx)
427 * Currently, we only create the obsolete_bpobj where there are
428 * indirect vdevs with referenced mappings.
430 ASSERT(spa_feature_is_active(dp->dp_spa, SPA_FEATURE_DEVICE_REMOVAL));
431 /* create and open the obsolete_bpobj */
432 obj = bpobj_alloc(dp->dp_meta_objset, SPA_OLD_MAXBLOCKSIZE, tx);
433 VERIFY0(bpobj_open(&dp->dp_obsolete_bpobj, dp->dp_meta_objset, obj));
434 VERIFY0(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
435 DMU_POOL_OBSOLETE_BPOBJ, sizeof (uint64_t), 1, &obj, tx));
436 spa_feature_incr(dp->dp_spa, SPA_FEATURE_OBSOLETE_COUNTS, tx);
440 dsl_pool_destroy_obsolete_bpobj(dsl_pool_t *dp, dmu_tx_t *tx)
442 spa_feature_decr(dp->dp_spa, SPA_FEATURE_OBSOLETE_COUNTS, tx);
443 VERIFY0(zap_remove(dp->dp_meta_objset,
444 DMU_POOL_DIRECTORY_OBJECT,
445 DMU_POOL_OBSOLETE_BPOBJ, tx));
446 bpobj_free(dp->dp_meta_objset,
447 dp->dp_obsolete_bpobj.bpo_object, tx);
448 bpobj_close(&dp->dp_obsolete_bpobj);
452 dsl_pool_create(spa_t *spa, nvlist_t *zplprops, dsl_crypto_params_t *dcp,
456 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
457 dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg);
461 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
463 /* create and open the MOS (meta-objset) */
464 dp->dp_meta_objset = dmu_objset_create_impl(spa,
465 NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx);
466 spa->spa_meta_objset = dp->dp_meta_objset;
468 /* create the pool directory */
469 err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
470 DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx);
473 /* Initialize scan structures */
474 VERIFY0(dsl_scan_init(dp, txg));
476 /* create and open the root dir */
477 dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx);
478 VERIFY0(dsl_dir_hold_obj(dp, dp->dp_root_dir_obj,
479 NULL, dp, &dp->dp_root_dir));
481 /* create and open the meta-objset dir */
482 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx);
483 VERIFY0(dsl_pool_open_special_dir(dp,
484 MOS_DIR_NAME, &dp->dp_mos_dir));
486 if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {
487 /* create and open the free dir */
488 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
490 VERIFY0(dsl_pool_open_special_dir(dp,
491 FREE_DIR_NAME, &dp->dp_free_dir));
493 /* create and open the free_bplist */
494 obj = bpobj_alloc(dp->dp_meta_objset, SPA_OLD_MAXBLOCKSIZE, tx);
495 VERIFY(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
496 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx) == 0);
497 VERIFY0(bpobj_open(&dp->dp_free_bpobj,
498 dp->dp_meta_objset, obj));
501 if (spa_version(spa) >= SPA_VERSION_DSL_SCRUB)
502 dsl_pool_create_origin(dp, tx);
505 * Some features may be needed when creating the root dataset, so we
506 * create the feature objects here.
508 if (spa_version(spa) >= SPA_VERSION_FEATURES)
509 spa_feature_create_zap_objects(spa, tx);
511 if (dcp != NULL && dcp->cp_crypt != ZIO_CRYPT_OFF &&
512 dcp->cp_crypt != ZIO_CRYPT_INHERIT)
513 spa_feature_enable(spa, SPA_FEATURE_ENCRYPTION, tx);
515 /* create the root dataset */
516 obj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, dcp, 0, tx);
518 /* create the root objset */
519 VERIFY0(dsl_dataset_hold_obj(dp, obj, FTAG, &ds));
523 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
524 os = dmu_objset_create_impl(dp->dp_spa, ds,
525 dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx);
526 rrw_exit(&ds->ds_bp_rwlock, FTAG);
527 zfs_create_fs(os, kcred, zplprops, tx);
530 dsl_dataset_rele(ds, FTAG);
534 rrw_exit(&dp->dp_config_rwlock, FTAG);
540 * Account for the meta-objset space in its placeholder dsl_dir.
543 dsl_pool_mos_diduse_space(dsl_pool_t *dp,
544 int64_t used, int64_t comp, int64_t uncomp)
546 ASSERT3U(comp, ==, uncomp); /* it's all metadata */
547 mutex_enter(&dp->dp_lock);
548 dp->dp_mos_used_delta += used;
549 dp->dp_mos_compressed_delta += comp;
550 dp->dp_mos_uncompressed_delta += uncomp;
551 mutex_exit(&dp->dp_lock);
555 dsl_pool_sync_mos(dsl_pool_t *dp, dmu_tx_t *tx)
557 zio_t *zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
558 dmu_objset_sync(dp->dp_meta_objset, zio, tx);
559 VERIFY0(zio_wait(zio));
560 dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
561 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
565 dsl_pool_dirty_delta(dsl_pool_t *dp, int64_t delta)
567 ASSERT(MUTEX_HELD(&dp->dp_lock));
570 ASSERT3U(-delta, <=, dp->dp_dirty_total);
572 dp->dp_dirty_total += delta;
575 * Note: we signal even when increasing dp_dirty_total.
576 * This ensures forward progress -- each thread wakes the next waiter.
578 if (dp->dp_dirty_total < zfs_dirty_data_max)
579 cv_signal(&dp->dp_spaceavail_cv);
584 dsl_early_sync_task_verify(dsl_pool_t *dp, uint64_t txg)
586 spa_t *spa = dp->dp_spa;
587 vdev_t *rvd = spa->spa_root_vdev;
589 for (uint64_t c = 0; c < rvd->vdev_children; c++) {
590 vdev_t *vd = rvd->vdev_child[c];
591 txg_list_t *tl = &vd->vdev_ms_list;
594 for (ms = txg_list_head(tl, TXG_CLEAN(txg)); ms;
595 ms = txg_list_next(tl, ms, TXG_CLEAN(txg))) {
596 VERIFY(range_tree_is_empty(ms->ms_freeing));
597 VERIFY(range_tree_is_empty(ms->ms_checkpointing));
606 dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
612 objset_t *mos = dp->dp_meta_objset;
613 list_t synced_datasets;
615 list_create(&synced_datasets, sizeof (dsl_dataset_t),
616 offsetof(dsl_dataset_t, ds_synced_link));
618 tx = dmu_tx_create_assigned(dp, txg);
621 * Run all early sync tasks before writing out any dirty blocks.
622 * For more info on early sync tasks see block comment in
623 * dsl_early_sync_task().
625 if (!txg_list_empty(&dp->dp_early_sync_tasks, txg)) {
626 dsl_sync_task_t *dst;
628 ASSERT3U(spa_sync_pass(dp->dp_spa), ==, 1);
630 txg_list_remove(&dp->dp_early_sync_tasks, txg)) != NULL) {
631 ASSERT(dsl_early_sync_task_verify(dp, txg));
632 dsl_sync_task_sync(dst, tx);
634 ASSERT(dsl_early_sync_task_verify(dp, txg));
638 * Write out all dirty blocks of dirty datasets.
640 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
641 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) {
643 * We must not sync any non-MOS datasets twice, because
644 * we may have taken a snapshot of them. However, we
645 * may sync newly-created datasets on pass 2.
647 ASSERT(!list_link_active(&ds->ds_synced_link));
648 list_insert_tail(&synced_datasets, ds);
649 dsl_dataset_sync(ds, zio, tx);
651 VERIFY0(zio_wait(zio));
654 * We have written all of the accounted dirty data, so our
655 * dp_space_towrite should now be zero. However, some seldom-used
656 * code paths do not adhere to this (e.g. dbuf_undirty(), also
657 * rounding error in dbuf_write_physdone).
658 * Shore up the accounting of any dirtied space now.
660 dsl_pool_undirty_space(dp, dp->dp_dirty_pertxg[txg & TXG_MASK], txg);
663 * Update the long range free counter after
664 * we're done syncing user data
666 mutex_enter(&dp->dp_lock);
667 ASSERT(spa_sync_pass(dp->dp_spa) == 1 ||
668 dp->dp_long_free_dirty_pertxg[txg & TXG_MASK] == 0);
669 dp->dp_long_free_dirty_pertxg[txg & TXG_MASK] = 0;
670 mutex_exit(&dp->dp_lock);
673 * After the data blocks have been written (ensured by the zio_wait()
674 * above), update the user/group/project space accounting. This happens
675 * in tasks dispatched to dp_sync_taskq, so wait for them before
678 for (ds = list_head(&synced_datasets); ds != NULL;
679 ds = list_next(&synced_datasets, ds)) {
680 dmu_objset_do_userquota_updates(ds->ds_objset, tx);
682 taskq_wait(dp->dp_sync_taskq);
685 * Sync the datasets again to push out the changes due to
686 * userspace updates. This must be done before we process the
687 * sync tasks, so that any snapshots will have the correct
688 * user accounting information (and we won't get confused
689 * about which blocks are part of the snapshot).
691 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
692 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) {
693 ASSERT(list_link_active(&ds->ds_synced_link));
694 dmu_buf_rele(ds->ds_dbuf, ds);
695 dsl_dataset_sync(ds, zio, tx);
697 VERIFY0(zio_wait(zio));
700 * Now that the datasets have been completely synced, we can
701 * clean up our in-memory structures accumulated while syncing:
703 * - move dead blocks from the pending deadlist to the on-disk deadlist
704 * - release hold from dsl_dataset_dirty()
706 while ((ds = list_remove_head(&synced_datasets)) != NULL) {
707 dsl_dataset_sync_done(ds, tx);
710 while ((dd = txg_list_remove(&dp->dp_dirty_dirs, txg)) != NULL) {
711 dsl_dir_sync(dd, tx);
715 * The MOS's space is accounted for in the pool/$MOS
716 * (dp_mos_dir). We can't modify the mos while we're syncing
717 * it, so we remember the deltas and apply them here.
719 if (dp->dp_mos_used_delta != 0 || dp->dp_mos_compressed_delta != 0 ||
720 dp->dp_mos_uncompressed_delta != 0) {
721 dsl_dir_diduse_space(dp->dp_mos_dir, DD_USED_HEAD,
722 dp->dp_mos_used_delta,
723 dp->dp_mos_compressed_delta,
724 dp->dp_mos_uncompressed_delta, tx);
725 dp->dp_mos_used_delta = 0;
726 dp->dp_mos_compressed_delta = 0;
727 dp->dp_mos_uncompressed_delta = 0;
730 if (!multilist_is_empty(mos->os_dirty_dnodes[txg & TXG_MASK])) {
731 dsl_pool_sync_mos(dp, tx);
735 * If we modify a dataset in the same txg that we want to destroy it,
736 * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it.
737 * dsl_dir_destroy_check() will fail if there are unexpected holds.
738 * Therefore, we want to sync the MOS (thus syncing the dd_dbuf
739 * and clearing the hold on it) before we process the sync_tasks.
740 * The MOS data dirtied by the sync_tasks will be synced on the next
743 if (!txg_list_empty(&dp->dp_sync_tasks, txg)) {
744 dsl_sync_task_t *dst;
746 * No more sync tasks should have been added while we
749 ASSERT3U(spa_sync_pass(dp->dp_spa), ==, 1);
750 while ((dst = txg_list_remove(&dp->dp_sync_tasks, txg)) != NULL)
751 dsl_sync_task_sync(dst, tx);
756 DTRACE_PROBE2(dsl_pool_sync__done, dsl_pool_t *dp, dp, uint64_t, txg);
760 dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg)
764 while ((zilog = txg_list_head(&dp->dp_dirty_zilogs, txg))) {
765 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
767 * We don't remove the zilog from the dp_dirty_zilogs
768 * list until after we've cleaned it. This ensures that
769 * callers of zilog_is_dirty() receive an accurate
770 * answer when they are racing with the spa sync thread.
772 zil_clean(zilog, txg);
773 (void) txg_list_remove_this(&dp->dp_dirty_zilogs, zilog, txg);
774 ASSERT(!dmu_objset_is_dirty(zilog->zl_os, txg));
775 dmu_buf_rele(ds->ds_dbuf, zilog);
777 ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg));
781 * TRUE if the current thread is the tx_sync_thread or if we
782 * are being called from SPA context during pool initialization.
785 dsl_pool_sync_context(dsl_pool_t *dp)
787 return (curthread == dp->dp_tx.tx_sync_thread ||
788 spa_is_initializing(dp->dp_spa) ||
789 taskq_member(dp->dp_sync_taskq, curthread));
793 * This function returns the amount of allocatable space in the pool
794 * minus whatever space is currently reserved by ZFS for specific
795 * purposes. Specifically:
797 * 1] Any reserved SLOP space
798 * 2] Any space used by the checkpoint
799 * 3] Any space used for deferred frees
801 * The latter 2 are especially important because they are needed to
802 * rectify the SPA's and DMU's different understanding of how much space
803 * is used. Now the DMU is aware of that extra space tracked by the SPA
804 * without having to maintain a separate special dir (e.g similar to
805 * $MOS, $FREEING, and $LEAKED).
807 * Note: By deferred frees here, we mean the frees that were deferred
808 * in spa_sync() after sync pass 1 (spa_deferred_bpobj), and not the
809 * segments placed in ms_defer trees during metaslab_sync_done().
812 dsl_pool_adjustedsize(dsl_pool_t *dp, zfs_space_check_t slop_policy)
814 spa_t *spa = dp->dp_spa;
815 uint64_t space, resv, adjustedsize;
816 uint64_t spa_deferred_frees =
817 spa->spa_deferred_bpobj.bpo_phys->bpo_bytes;
819 space = spa_get_dspace(spa)
820 - spa_get_checkpoint_space(spa) - spa_deferred_frees;
821 resv = spa_get_slop_space(spa);
823 switch (slop_policy) {
824 case ZFS_SPACE_CHECK_NORMAL:
826 case ZFS_SPACE_CHECK_RESERVED:
829 case ZFS_SPACE_CHECK_EXTRA_RESERVED:
832 case ZFS_SPACE_CHECK_NONE:
836 panic("invalid slop policy value: %d", slop_policy);
839 adjustedsize = (space >= resv) ? (space - resv) : 0;
841 return (adjustedsize);
845 dsl_pool_unreserved_space(dsl_pool_t *dp, zfs_space_check_t slop_policy)
847 uint64_t poolsize = dsl_pool_adjustedsize(dp, slop_policy);
849 metaslab_class_get_deferred(spa_normal_class(dp->dp_spa));
850 uint64_t quota = (poolsize >= deferred) ? (poolsize - deferred) : 0;
855 dsl_pool_need_dirty_delay(dsl_pool_t *dp)
857 uint64_t delay_min_bytes =
858 zfs_dirty_data_max * zfs_delay_min_dirty_percent / 100;
861 mutex_enter(&dp->dp_lock);
862 if (dp->dp_dirty_total > zfs_dirty_data_sync)
864 rv = (dp->dp_dirty_total > delay_min_bytes);
865 mutex_exit(&dp->dp_lock);
870 dsl_pool_dirty_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
873 mutex_enter(&dp->dp_lock);
874 dp->dp_dirty_pertxg[tx->tx_txg & TXG_MASK] += space;
875 dsl_pool_dirty_delta(dp, space);
876 mutex_exit(&dp->dp_lock);
881 dsl_pool_undirty_space(dsl_pool_t *dp, int64_t space, uint64_t txg)
883 ASSERT3S(space, >=, 0);
887 mutex_enter(&dp->dp_lock);
888 if (dp->dp_dirty_pertxg[txg & TXG_MASK] < space) {
889 /* XXX writing something we didn't dirty? */
890 space = dp->dp_dirty_pertxg[txg & TXG_MASK];
892 ASSERT3U(dp->dp_dirty_pertxg[txg & TXG_MASK], >=, space);
893 dp->dp_dirty_pertxg[txg & TXG_MASK] -= space;
894 ASSERT3U(dp->dp_dirty_total, >=, space);
895 dsl_pool_dirty_delta(dp, -space);
896 mutex_exit(&dp->dp_lock);
901 upgrade_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
904 dsl_dataset_t *ds, *prev = NULL;
907 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
911 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
912 err = dsl_dataset_hold_obj(dp,
913 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
915 dsl_dataset_rele(ds, FTAG);
919 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object)
921 dsl_dataset_rele(ds, FTAG);
927 prev = dp->dp_origin_snap;
930 * The $ORIGIN can't have any data, or the accounting
933 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
934 ASSERT0(dsl_dataset_phys(prev)->ds_bp.blk_birth);
935 rrw_exit(&ds->ds_bp_rwlock, FTAG);
937 /* The origin doesn't get attached to itself */
938 if (ds->ds_object == prev->ds_object) {
939 dsl_dataset_rele(ds, FTAG);
943 dmu_buf_will_dirty(ds->ds_dbuf, tx);
944 dsl_dataset_phys(ds)->ds_prev_snap_obj = prev->ds_object;
945 dsl_dataset_phys(ds)->ds_prev_snap_txg =
946 dsl_dataset_phys(prev)->ds_creation_txg;
948 dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
949 dsl_dir_phys(ds->ds_dir)->dd_origin_obj = prev->ds_object;
951 dmu_buf_will_dirty(prev->ds_dbuf, tx);
952 dsl_dataset_phys(prev)->ds_num_children++;
954 if (dsl_dataset_phys(ds)->ds_next_snap_obj == 0) {
955 ASSERT(ds->ds_prev == NULL);
956 VERIFY0(dsl_dataset_hold_obj(dp,
957 dsl_dataset_phys(ds)->ds_prev_snap_obj,
962 ASSERT3U(dsl_dir_phys(ds->ds_dir)->dd_origin_obj, ==, prev->ds_object);
963 ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_obj, ==, prev->ds_object);
965 if (dsl_dataset_phys(prev)->ds_next_clones_obj == 0) {
966 dmu_buf_will_dirty(prev->ds_dbuf, tx);
967 dsl_dataset_phys(prev)->ds_next_clones_obj =
968 zap_create(dp->dp_meta_objset,
969 DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
971 VERIFY0(zap_add_int(dp->dp_meta_objset,
972 dsl_dataset_phys(prev)->ds_next_clones_obj, ds->ds_object, tx));
974 dsl_dataset_rele(ds, FTAG);
975 if (prev != dp->dp_origin_snap)
976 dsl_dataset_rele(prev, FTAG);
981 dsl_pool_upgrade_clones(dsl_pool_t *dp, dmu_tx_t *tx)
983 ASSERT(dmu_tx_is_syncing(tx));
984 ASSERT(dp->dp_origin_snap != NULL);
986 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj, upgrade_clones_cb,
987 tx, DS_FIND_CHILDREN | DS_FIND_SERIALIZE));
992 upgrade_dir_clones_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
995 objset_t *mos = dp->dp_meta_objset;
997 if (dsl_dir_phys(ds->ds_dir)->dd_origin_obj != 0) {
998 dsl_dataset_t *origin;
1000 VERIFY0(dsl_dataset_hold_obj(dp,
1001 dsl_dir_phys(ds->ds_dir)->dd_origin_obj, FTAG, &origin));
1003 if (dsl_dir_phys(origin->ds_dir)->dd_clones == 0) {
1004 dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
1005 dsl_dir_phys(origin->ds_dir)->dd_clones =
1006 zap_create(mos, DMU_OT_DSL_CLONES, DMU_OT_NONE,
1010 VERIFY0(zap_add_int(dp->dp_meta_objset,
1011 dsl_dir_phys(origin->ds_dir)->dd_clones,
1012 ds->ds_object, tx));
1014 dsl_dataset_rele(origin, FTAG);
1020 dsl_pool_upgrade_dir_clones(dsl_pool_t *dp, dmu_tx_t *tx)
1024 ASSERT(dmu_tx_is_syncing(tx));
1026 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, FREE_DIR_NAME, tx);
1027 VERIFY0(dsl_pool_open_special_dir(dp,
1028 FREE_DIR_NAME, &dp->dp_free_dir));
1031 * We can't use bpobj_alloc(), because spa_version() still
1032 * returns the old version, and we need a new-version bpobj with
1033 * subobj support. So call dmu_object_alloc() directly.
1035 obj = dmu_object_alloc(dp->dp_meta_objset, DMU_OT_BPOBJ,
1036 SPA_OLD_MAXBLOCKSIZE, DMU_OT_BPOBJ_HDR, sizeof (bpobj_phys_t), tx);
1037 VERIFY0(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
1038 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx));
1039 VERIFY0(bpobj_open(&dp->dp_free_bpobj, dp->dp_meta_objset, obj));
1041 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1042 upgrade_dir_clones_cb, tx, DS_FIND_CHILDREN | DS_FIND_SERIALIZE));
1046 dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx)
1051 ASSERT(dmu_tx_is_syncing(tx));
1052 ASSERT(dp->dp_origin_snap == NULL);
1053 ASSERT(rrw_held(&dp->dp_config_rwlock, RW_WRITER));
1055 /* create the origin dir, ds, & snap-ds */
1056 dsobj = dsl_dataset_create_sync(dp->dp_root_dir, ORIGIN_DIR_NAME,
1057 NULL, 0, kcred, NULL, tx);
1058 VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1059 dsl_dataset_snapshot_sync_impl(ds, ORIGIN_DIR_NAME, tx);
1060 VERIFY0(dsl_dataset_hold_obj(dp, dsl_dataset_phys(ds)->ds_prev_snap_obj,
1061 dp, &dp->dp_origin_snap));
1062 dsl_dataset_rele(ds, FTAG);
1066 dsl_pool_iput_taskq(dsl_pool_t *dp)
1068 return (dp->dp_iput_taskq);
1072 * Walk through the pool-wide zap object of temporary snapshot user holds
1076 dsl_pool_clean_tmp_userrefs(dsl_pool_t *dp)
1080 objset_t *mos = dp->dp_meta_objset;
1081 uint64_t zapobj = dp->dp_tmp_userrefs_obj;
1086 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
1088 holds = fnvlist_alloc();
1090 for (zap_cursor_init(&zc, mos, zapobj);
1091 zap_cursor_retrieve(&zc, &za) == 0;
1092 zap_cursor_advance(&zc)) {
1096 htag = strchr(za.za_name, '-');
1099 if (nvlist_lookup_nvlist(holds, za.za_name, &tags) != 0) {
1100 tags = fnvlist_alloc();
1101 fnvlist_add_boolean(tags, htag);
1102 fnvlist_add_nvlist(holds, za.za_name, tags);
1105 fnvlist_add_boolean(tags, htag);
1108 dsl_dataset_user_release_tmp(dp, holds);
1109 fnvlist_free(holds);
1110 zap_cursor_fini(&zc);
1114 * Create the pool-wide zap object for storing temporary snapshot holds.
1117 dsl_pool_user_hold_create_obj(dsl_pool_t *dp, dmu_tx_t *tx)
1119 objset_t *mos = dp->dp_meta_objset;
1121 ASSERT(dp->dp_tmp_userrefs_obj == 0);
1122 ASSERT(dmu_tx_is_syncing(tx));
1124 dp->dp_tmp_userrefs_obj = zap_create_link(mos, DMU_OT_USERREFS,
1125 DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_TMP_USERREFS, tx);
1129 dsl_pool_user_hold_rele_impl(dsl_pool_t *dp, uint64_t dsobj,
1130 const char *tag, uint64_t now, dmu_tx_t *tx, boolean_t holding)
1132 objset_t *mos = dp->dp_meta_objset;
1133 uint64_t zapobj = dp->dp_tmp_userrefs_obj;
1137 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
1138 ASSERT(dmu_tx_is_syncing(tx));
1141 * If the pool was created prior to SPA_VERSION_USERREFS, the
1142 * zap object for temporary holds might not exist yet.
1146 dsl_pool_user_hold_create_obj(dp, tx);
1147 zapobj = dp->dp_tmp_userrefs_obj;
1149 return (SET_ERROR(ENOENT));
1153 name = kmem_asprintf("%llx-%s", (u_longlong_t)dsobj, tag);
1155 error = zap_add(mos, zapobj, name, 8, 1, &now, tx);
1157 error = zap_remove(mos, zapobj, name, tx);
1164 * Add a temporary hold for the given dataset object and tag.
1167 dsl_pool_user_hold(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
1168 uint64_t now, dmu_tx_t *tx)
1170 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, now, tx, B_TRUE));
1174 * Release a temporary hold for the given dataset object and tag.
1177 dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
1180 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, 0,
1185 * DSL Pool Configuration Lock
1187 * The dp_config_rwlock protects against changes to DSL state (e.g. dataset
1188 * creation / destruction / rename / property setting). It must be held for
1189 * read to hold a dataset or dsl_dir. I.e. you must call
1190 * dsl_pool_config_enter() or dsl_pool_hold() before calling
1191 * dsl_{dataset,dir}_hold{_obj}. In most circumstances, the dp_config_rwlock
1192 * must be held continuously until all datasets and dsl_dirs are released.
1194 * The only exception to this rule is that if a "long hold" is placed on
1195 * a dataset, then the dp_config_rwlock may be dropped while the dataset
1196 * is still held. The long hold will prevent the dataset from being
1197 * destroyed -- the destroy will fail with EBUSY. A long hold can be
1198 * obtained by calling dsl_dataset_long_hold(), or by "owning" a dataset
1199 * (by calling dsl_{dataset,objset}_{try}own{_obj}).
1201 * Legitimate long-holders (including owners) should be long-running, cancelable
1202 * tasks that should cause "zfs destroy" to fail. This includes DMU
1203 * consumers (i.e. a ZPL filesystem being mounted or ZVOL being open),
1204 * "zfs send", and "zfs diff". There are several other long-holders whose
1205 * uses are suboptimal (e.g. "zfs promote", and zil_suspend()).
1207 * The usual formula for long-holding would be:
1209 * dsl_dataset_hold()
1210 * ... perform checks ...
1211 * dsl_dataset_long_hold()
1213 * ... perform long-running task ...
1214 * dsl_dataset_long_rele()
1215 * dsl_dataset_rele()
1217 * Note that when the long hold is released, the dataset is still held but
1218 * the pool is not held. The dataset may change arbitrarily during this time
1219 * (e.g. it could be destroyed). Therefore you shouldn't do anything to the
1220 * dataset except release it.
1222 * User-initiated operations (e.g. ioctls, zfs_ioc_*()) are either read-only
1223 * or modifying operations.
1225 * Modifying operations should generally use dsl_sync_task(). The synctask
1226 * infrastructure enforces proper locking strategy with respect to the
1227 * dp_config_rwlock. See the comment above dsl_sync_task() for details.
1229 * Read-only operations will manually hold the pool, then the dataset, obtain
1230 * information from the dataset, then release the pool and dataset.
1231 * dmu_objset_{hold,rele}() are convenience routines that also do the pool
1236 dsl_pool_hold(const char *name, void *tag, dsl_pool_t **dp)
1241 error = spa_open(name, &spa, tag);
1243 *dp = spa_get_dsl(spa);
1244 dsl_pool_config_enter(*dp, tag);
1250 dsl_pool_rele(dsl_pool_t *dp, void *tag)
1252 dsl_pool_config_exit(dp, tag);
1253 spa_close(dp->dp_spa, tag);
1257 dsl_pool_config_enter(dsl_pool_t *dp, void *tag)
1260 * We use a "reentrant" reader-writer lock, but not reentrantly.
1262 * The rrwlock can (with the track_all flag) track all reading threads,
1263 * which is very useful for debugging which code path failed to release
1264 * the lock, and for verifying that the *current* thread does hold
1267 * (Unlike a rwlock, which knows that N threads hold it for
1268 * read, but not *which* threads, so rw_held(RW_READER) returns TRUE
1269 * if any thread holds it for read, even if this thread doesn't).
1271 ASSERT(!rrw_held(&dp->dp_config_rwlock, RW_READER));
1272 rrw_enter(&dp->dp_config_rwlock, RW_READER, tag);
1276 dsl_pool_config_enter_prio(dsl_pool_t *dp, void *tag)
1278 ASSERT(!rrw_held(&dp->dp_config_rwlock, RW_READER));
1279 rrw_enter_read_prio(&dp->dp_config_rwlock, tag);
1283 dsl_pool_config_exit(dsl_pool_t *dp, void *tag)
1285 rrw_exit(&dp->dp_config_rwlock, tag);
1289 dsl_pool_config_held(dsl_pool_t *dp)
1291 return (RRW_LOCK_HELD(&dp->dp_config_rwlock));
1295 dsl_pool_config_held_writer(dsl_pool_t *dp)
1297 return (RRW_WRITE_HELD(&dp->dp_config_rwlock));
1300 #if defined(_KERNEL)
1301 EXPORT_SYMBOL(dsl_pool_config_enter);
1302 EXPORT_SYMBOL(dsl_pool_config_exit);
1305 /* zfs_dirty_data_max_percent only applied at module load in arc_init(). */
1306 module_param(zfs_dirty_data_max_percent, int, 0444);
1307 MODULE_PARM_DESC(zfs_dirty_data_max_percent, "percent of ram can be dirty");
1309 /* zfs_dirty_data_max_max_percent only applied at module load in arc_init(). */
1310 module_param(zfs_dirty_data_max_max_percent, int, 0444);
1311 MODULE_PARM_DESC(zfs_dirty_data_max_max_percent,
1312 "zfs_dirty_data_max upper bound as % of RAM");
1314 module_param(zfs_delay_min_dirty_percent, int, 0644);
1315 MODULE_PARM_DESC(zfs_delay_min_dirty_percent, "transaction delay threshold");
1317 module_param(zfs_dirty_data_max, ulong, 0644);
1318 MODULE_PARM_DESC(zfs_dirty_data_max, "determines the dirty space limit");
1320 /* zfs_dirty_data_max_max only applied at module load in arc_init(). */
1321 module_param(zfs_dirty_data_max_max, ulong, 0444);
1322 MODULE_PARM_DESC(zfs_dirty_data_max_max,
1323 "zfs_dirty_data_max upper bound in bytes");
1325 module_param(zfs_dirty_data_sync, ulong, 0644);
1326 MODULE_PARM_DESC(zfs_dirty_data_sync, "sync txg when this much dirty data");
1328 module_param(zfs_delay_scale, ulong, 0644);
1329 MODULE_PARM_DESC(zfs_delay_scale, "how quickly delay approaches infinity");
1331 module_param(zfs_sync_taskq_batch_pct, int, 0644);
1332 MODULE_PARM_DESC(zfs_sync_taskq_batch_pct,
1333 "max percent of CPUs that are used to sync dirty data");
1335 module_param(zfs_zil_clean_taskq_nthr_pct, int, 0644);
1336 MODULE_PARM_DESC(zfs_zil_clean_taskq_nthr_pct,
1337 "max percent of CPUs that are used per dp_sync_taskq");
1339 module_param(zfs_zil_clean_taskq_minalloc, int, 0644);
1340 MODULE_PARM_DESC(zfs_zil_clean_taskq_minalloc,
1341 "number of taskq entries that are pre-populated");
1343 module_param(zfs_zil_clean_taskq_maxalloc, int, 0644);
1344 MODULE_PARM_DESC(zfs_zil_clean_taskq_maxalloc,
1345 "max number of taskq entries that are cached");