*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2013 Steven Hartland. All rights reserved.
*/
#include <sys/dsl_pool.h>
#include <sys/dsl_deadlist.h>
#include <sys/bptree.h>
#include <sys/zfeature.h>
+#include <sys/zil_impl.h>
+#include <sys/dsl_userhold.h>
-int zfs_no_write_throttle = 0;
-int zfs_write_limit_shift = 3; /* 1/8th of physical memory */
-int zfs_txg_synctime_ms = 1000; /* target millisecs to sync a txg */
-int zfs_txg_history = 60; /* statistics for the last N txgs */
-
-unsigned long zfs_write_limit_min = 32 << 20; /* min write limit is 32MB */
-unsigned long zfs_write_limit_max = 0; /* max data payload per txg */
-unsigned long zfs_write_limit_inflated = 0;
-unsigned long zfs_write_limit_override = 0;
-
-kmutex_t zfs_write_limit_lock;
-
-static pgcnt_t old_physmem = 0;
-
-static int
-dsl_pool_txg_history_update(kstat_t *ksp, int rw)
-{
- dsl_pool_t *dp = ksp->ks_private;
- txg_history_t *th;
- int i = 0;
-
- if (rw == KSTAT_WRITE)
- return (EACCES);
-
- if (ksp->ks_data)
- kmem_free(ksp->ks_data, ksp->ks_data_size);
-
- mutex_enter(&dp->dp_lock);
-
- ksp->ks_ndata = dp->dp_txg_history_size;
- ksp->ks_data_size = dp->dp_txg_history_size * sizeof(kstat_txg_t);
- if (ksp->ks_data_size > 0)
- ksp->ks_data = kmem_alloc(ksp->ks_data_size, KM_PUSHPAGE);
-
- /* Traversed oldest to youngest for the most readable kstat output */
- for (th = list_tail(&dp->dp_txg_history); th != NULL;
- th = list_prev(&dp->dp_txg_history, th)) {
- mutex_enter(&th->th_lock);
- ASSERT3S(i + sizeof(kstat_txg_t), <=, ksp->ks_data_size);
- memcpy(ksp->ks_data + i, &th->th_kstat, sizeof(kstat_txg_t));
- i += sizeof(kstat_txg_t);
- mutex_exit(&th->th_lock);
- }
-
- mutex_exit(&dp->dp_lock);
-
- return (0);
-}
-
-static void
-dsl_pool_txg_history_init(dsl_pool_t *dp, uint64_t txg)
-{
- char name[KSTAT_STRLEN];
-
- list_create(&dp->dp_txg_history, sizeof (txg_history_t),
- offsetof(txg_history_t, th_link));
- dsl_pool_txg_history_add(dp, txg);
-
- (void) snprintf(name, KSTAT_STRLEN, "txgs-%s", spa_name(dp->dp_spa));
- dp->dp_txg_kstat = kstat_create("zfs", 0, name, "misc",
- KSTAT_TYPE_TXG, 0, KSTAT_FLAG_VIRTUAL);
- if (dp->dp_txg_kstat) {
- dp->dp_txg_kstat->ks_data = NULL;
- dp->dp_txg_kstat->ks_private = dp;
- dp->dp_txg_kstat->ks_update = dsl_pool_txg_history_update;
- kstat_install(dp->dp_txg_kstat);
- }
-}
-
-static void
-dsl_pool_txg_history_destroy(dsl_pool_t *dp)
-{
- txg_history_t *th;
-
- if (dp->dp_txg_kstat) {
- if (dp->dp_txg_kstat->ks_data)
- kmem_free(dp->dp_txg_kstat->ks_data,
- dp->dp_txg_kstat->ks_data_size);
-
- kstat_delete(dp->dp_txg_kstat);
- }
-
- mutex_enter(&dp->dp_lock);
- while ((th = list_remove_head(&dp->dp_txg_history))) {
- dp->dp_txg_history_size--;
- mutex_destroy(&th->th_lock);
- kmem_free(th, sizeof(txg_history_t));
- }
-
- ASSERT3U(dp->dp_txg_history_size, ==, 0);
- list_destroy(&dp->dp_txg_history);
- mutex_exit(&dp->dp_lock);
-}
-
-txg_history_t *
-dsl_pool_txg_history_add(dsl_pool_t *dp, uint64_t txg)
-{
- txg_history_t *th, *rm;
-
- th = kmem_zalloc(sizeof(txg_history_t), KM_SLEEP);
- mutex_init(&th->th_lock, NULL, MUTEX_DEFAULT, NULL);
- th->th_kstat.txg = txg;
- th->th_kstat.state = TXG_STATE_OPEN;
- th->th_kstat.birth = gethrtime();
-
- mutex_enter(&dp->dp_lock);
-
- list_insert_head(&dp->dp_txg_history, th);
- dp->dp_txg_history_size++;
-
- while (dp->dp_txg_history_size > zfs_txg_history) {
- dp->dp_txg_history_size--;
- rm = list_remove_tail(&dp->dp_txg_history);
- mutex_destroy(&rm->th_lock);
- kmem_free(rm, sizeof(txg_history_t));
- }
-
- mutex_exit(&dp->dp_lock);
+/*
+ * ZFS Write Throttle
+ * ------------------
+ *
+ * ZFS must limit the rate of incoming writes to the rate at which it is able
+ * to sync data modifications to the backend storage. Throttling by too much
+ * creates an artificial limit; throttling by too little can only be sustained
+ * for short periods and would lead to highly lumpy performance. On a per-pool
+ * basis, ZFS tracks the amount of modified (dirty) data. As operations change
+ * data, the amount of dirty data increases; as ZFS syncs out data, the amount
+ * of dirty data decreases. When the amount of dirty data exceeds a
+ * predetermined threshold further modifications are blocked until the amount
+ * of dirty data decreases (as data is synced out).
+ *
+ * The limit on dirty data is tunable, and should be adjusted according to
+ * both the IO capacity and available memory of the system. The larger the
+ * window, the more ZFS is able to aggregate and amortize metadata (and data)
+ * changes. However, memory is a limited resource, and allowing for more dirty
+ * data comes at the cost of keeping other useful data in memory (for example
+ * ZFS data cached by the ARC).
+ *
+ * Implementation
+ *
+ * As buffers are modified dsl_pool_willuse_space() increments both the per-
+ * txg (dp_dirty_pertxg[]) and poolwide (dp_dirty_total) accounting of
+ * dirty space used; dsl_pool_dirty_space() decrements those values as data
+ * is synced out from dsl_pool_sync(). While only the poolwide value is
+ * relevant, the per-txg value is useful for debugging. The tunable
+ * zfs_dirty_data_max determines the dirty space limit. Once that value is
+ * exceeded, new writes are halted until space frees up.
+ *
+ * The zfs_dirty_data_sync tunable dictates the threshold at which we
+ * ensure that there is a txg syncing (see the comment in txg.c for a full
+ * description of transaction group stages).
+ *
+ * The IO scheduler uses both the dirty space limit and current amount of
+ * dirty data as inputs. Those values affect the number of concurrent IOs ZFS
+ * issues. See the comment in vdev_queue.c for details of the IO scheduler.
+ *
+ * The delay is also calculated based on the amount of dirty data. See the
+ * comment above dmu_tx_delay() for details.
+ */
- return (th);
-}
+/*
+ * zfs_dirty_data_max will be set to zfs_dirty_data_max_percent% of all memory,
+ * capped at zfs_dirty_data_max_max. It can also be overridden with a module
+ * parameter.
+ */
+unsigned long zfs_dirty_data_max = 0;
+unsigned long zfs_dirty_data_max_max = 0;
+int zfs_dirty_data_max_percent = 10;
+int zfs_dirty_data_max_max_percent = 25;
/*
- * Traversed youngest to oldest because lookups are only done for open
- * or syncing txgs which are guaranteed to be at the head of the list.
- * The txg_history_t structure will be returned locked.
+ * If there is at least this much dirty data, push out a txg.
*/
-txg_history_t *
-dsl_pool_txg_history_get(dsl_pool_t *dp, uint64_t txg)
-{
- txg_history_t *th;
+unsigned long zfs_dirty_data_sync = 64 * 1024 * 1024;
- mutex_enter(&dp->dp_lock);
- for (th = list_head(&dp->dp_txg_history); th != NULL;
- th = list_next(&dp->dp_txg_history, th)) {
- if (th->th_kstat.txg == txg) {
- mutex_enter(&th->th_lock);
- break;
- }
- }
- mutex_exit(&dp->dp_lock);
+/*
+ * Once there is this amount of dirty data, the dmu_tx_delay() will kick in
+ * and delay each transaction.
+ * This value should be >= zfs_vdev_async_write_active_max_dirty_percent.
+ */
+int zfs_delay_min_dirty_percent = 60;
- return (th);
-}
+/*
+ * This controls how quickly the delay approaches infinity.
+ * Larger values cause it to delay more for a given amount of dirty data.
+ * Therefore larger values will cause there to be less dirty data for a
+ * given throughput.
+ *
+ * For the smoothest delay, this value should be about 1 billion divided
+ * by the maximum number of operations per second. This will smoothly
+ * handle between 10x and 1/10th this number.
+ *
+ * Note: zfs_delay_scale * zfs_dirty_data_max must be < 2^64, due to the
+ * multiply in dmu_tx_delay().
+ */
+unsigned long zfs_delay_scale = 1000 * 1000 * 1000 / 2000;
-void
-dsl_pool_txg_history_put(txg_history_t *th)
-{
- mutex_exit(&th->th_lock);
-}
+hrtime_t zfs_throttle_delay = MSEC2NSEC(10);
+hrtime_t zfs_throttle_resolution = MSEC2NSEC(10);
int
dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp)
if (err)
return (err);
- return (dsl_dir_open_obj(dp, obj, name, dp, ddp));
+ return (dsl_dir_hold_obj(dp, obj, name, dp, ddp));
}
static dsl_pool_t *
dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP);
dp->dp_spa = spa;
dp->dp_meta_rootbp = *bp;
- rw_init(&dp->dp_config_rwlock, NULL, RW_DEFAULT, NULL);
- dp->dp_write_limit = zfs_write_limit_min;
+ rrw_init(&dp->dp_config_rwlock, B_TRUE);
txg_init(dp, txg);
txg_list_create(&dp->dp_dirty_datasets,
offsetof(dsl_dataset_t, ds_dirty_link));
+ txg_list_create(&dp->dp_dirty_zilogs,
+ offsetof(zilog_t, zl_dirty_link));
txg_list_create(&dp->dp_dirty_dirs,
offsetof(dsl_dir_t, dd_dirty_link));
txg_list_create(&dp->dp_sync_tasks,
- offsetof(dsl_sync_task_group_t, dstg_node));
- list_create(&dp->dp_synced_datasets, sizeof (dsl_dataset_t),
- offsetof(dsl_dataset_t, ds_synced_link));
+ offsetof(dsl_sync_task_t, dst_node));
mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL);
+ cv_init(&dp->dp_spaceavail_cv, NULL, CV_DEFAULT, NULL);
dp->dp_iput_taskq = taskq_create("zfs_iput_taskq", 1, minclsyspri,
1, 4, 0);
- dsl_pool_txg_history_init(dp, txg);
-
return (dp);
}
dsl_dataset_t *ds;
uint64_t obj;
- rw_enter(&dp->dp_config_rwlock, RW_WRITER);
+ rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
&dp->dp_root_dir_obj);
if (err)
goto out;
- err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
+ err = dsl_dir_hold_obj(dp, dp->dp_root_dir_obj,
NULL, dp, &dp->dp_root_dir);
if (err)
goto out;
&dp->dp_origin_snap);
dsl_dataset_rele(ds, FTAG);
}
- dsl_dir_close(dd, dp);
+ dsl_dir_rele(dd, dp);
if (err)
goto out;
}
DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj);
if (err)
goto out;
- VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
+ VERIFY0(bpobj_open(&dp->dp_free_bpobj,
dp->dp_meta_objset, obj));
}
- if (spa_feature_is_active(dp->dp_spa,
- &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
+ if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
&dp->dp_bptree_obj);
goto out;
}
+ if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_EMPTY_BPOBJ)) {
+ err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+ DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
+ &dp->dp_empty_bpobj);
+ if (err != 0)
+ goto out;
+ }
+
err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1,
&dp->dp_tmp_userrefs_obj);
err = dsl_scan_init(dp, dp->dp_tx.tx_open_txg);
out:
- rw_exit(&dp->dp_config_rwlock);
+ rrw_exit(&dp->dp_config_rwlock, FTAG);
return (err);
}
void
dsl_pool_close(dsl_pool_t *dp)
{
- /* drop our references from dsl_pool_open() */
-
/*
+ * Drop our references from dsl_pool_open().
+ *
* Since we held the origin_snap from "syncing" context (which
* includes pool-opening context), it actually only got a "ref"
* and not a hold, so just drop that here.
*/
if (dp->dp_origin_snap)
- dsl_dataset_drop_ref(dp->dp_origin_snap, dp);
+ dsl_dataset_rele(dp->dp_origin_snap, dp);
if (dp->dp_mos_dir)
- dsl_dir_close(dp->dp_mos_dir, dp);
+ dsl_dir_rele(dp->dp_mos_dir, dp);
if (dp->dp_free_dir)
- dsl_dir_close(dp->dp_free_dir, dp);
+ dsl_dir_rele(dp->dp_free_dir, dp);
if (dp->dp_root_dir)
- dsl_dir_close(dp->dp_root_dir, dp);
+ dsl_dir_rele(dp->dp_root_dir, dp);
bpobj_close(&dp->dp_free_bpobj);
dmu_objset_evict(dp->dp_meta_objset);
txg_list_destroy(&dp->dp_dirty_datasets);
+ txg_list_destroy(&dp->dp_dirty_zilogs);
txg_list_destroy(&dp->dp_sync_tasks);
txg_list_destroy(&dp->dp_dirty_dirs);
- list_destroy(&dp->dp_synced_datasets);
arc_flush(dp->dp_spa);
txg_fini(dp);
dsl_scan_fini(dp);
- dsl_pool_txg_history_destroy(dp);
- rw_destroy(&dp->dp_config_rwlock);
+ rrw_destroy(&dp->dp_config_rwlock);
mutex_destroy(&dp->dp_lock);
taskq_destroy(dp->dp_iput_taskq);
if (dp->dp_blkstats)
dsl_dataset_t *ds;
uint64_t obj;
+ rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
+
/* create and open the MOS (meta-objset) */
dp->dp_meta_objset = dmu_objset_create_impl(spa,
NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx);
/* create the pool directory */
err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx);
- ASSERT3U(err, ==, 0);
+ ASSERT0(err);
/* Initialize scan structures */
- VERIFY3U(0, ==, dsl_scan_init(dp, txg));
+ VERIFY0(dsl_scan_init(dp, txg));
/* create and open the root dir */
dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx);
- VERIFY(0 == dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
+ VERIFY0(dsl_dir_hold_obj(dp, dp->dp_root_dir_obj,
NULL, dp, &dp->dp_root_dir));
/* create and open the meta-objset dir */
(void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx);
- VERIFY(0 == dsl_pool_open_special_dir(dp,
+ VERIFY0(dsl_pool_open_special_dir(dp,
MOS_DIR_NAME, &dp->dp_mos_dir));
if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {
/* create and open the free dir */
(void) dsl_dir_create_sync(dp, dp->dp_root_dir,
FREE_DIR_NAME, tx);
- VERIFY(0 == dsl_pool_open_special_dir(dp,
+ VERIFY0(dsl_pool_open_special_dir(dp,
FREE_DIR_NAME, &dp->dp_free_dir));
/* create and open the free_bplist */
obj = bpobj_alloc(dp->dp_meta_objset, SPA_MAXBLOCKSIZE, tx);
VERIFY(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx) == 0);
- VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
+ VERIFY0(bpobj_open(&dp->dp_free_bpobj,
dp->dp_meta_objset, obj));
}
obj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx);
/* create the root objset */
- VERIFY(0 == dsl_dataset_hold_obj(dp, obj, FTAG, &ds));
+ VERIFY0(dsl_dataset_hold_obj(dp, obj, FTAG, &ds));
VERIFY(NULL != (os = dmu_objset_create_impl(dp->dp_spa, ds,
dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx)));
#ifdef _KERNEL
dmu_tx_commit(tx);
+ rrw_exit(&dp->dp_config_rwlock, FTAG);
+
return (dp);
}
+/*
+ * Account for the meta-objset space in its placeholder dsl_dir.
+ */
+void
+dsl_pool_mos_diduse_space(dsl_pool_t *dp,
+ int64_t used, int64_t comp, int64_t uncomp)
+{
+ ASSERT3U(comp, ==, uncomp); /* it's all metadata */
+ mutex_enter(&dp->dp_lock);
+ dp->dp_mos_used_delta += used;
+ dp->dp_mos_compressed_delta += comp;
+ dp->dp_mos_uncompressed_delta += uncomp;
+ mutex_exit(&dp->dp_lock);
+}
+
static int
deadlist_enqueue_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
{
dsl_deadlist_t *dl = arg;
- dsl_pool_t *dp = dmu_objset_pool(dl->dl_os);
- rw_enter(&dp->dp_config_rwlock, RW_READER);
dsl_deadlist_insert(dl, bp, tx);
- rw_exit(&dp->dp_config_rwlock);
return (0);
}
+static void
+dsl_pool_sync_mos(dsl_pool_t *dp, dmu_tx_t *tx)
+{
+ zio_t *zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
+ dmu_objset_sync(dp->dp_meta_objset, zio, tx);
+ VERIFY0(zio_wait(zio));
+ dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
+ spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
+}
+
+static void
+dsl_pool_dirty_delta(dsl_pool_t *dp, int64_t delta)
+{
+ ASSERT(MUTEX_HELD(&dp->dp_lock));
+
+ if (delta < 0)
+ ASSERT3U(-delta, <=, dp->dp_dirty_total);
+
+ dp->dp_dirty_total += delta;
+
+ /*
+ * Note: we signal even when increasing dp_dirty_total.
+ * This ensures forward progress -- each thread wakes the next waiter.
+ */
+ if (dp->dp_dirty_total <= zfs_dirty_data_max)
+ cv_signal(&dp->dp_spaceavail_cv);
+}
+
void
dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
{
dmu_tx_t *tx;
dsl_dir_t *dd;
dsl_dataset_t *ds;
- dsl_sync_task_group_t *dstg;
objset_t *mos = dp->dp_meta_objset;
- hrtime_t start, write_time;
- uint64_t data_written;
- int err;
+ list_t synced_datasets;
- /*
- * We need to copy dp_space_towrite() before doing
- * dsl_sync_task_group_sync(), because
- * dsl_dataset_snapshot_reserve_space() will increase
- * dp_space_towrite but not actually write anything.
- */
- data_written = dp->dp_space_towrite[txg & TXG_MASK];
+ list_create(&synced_datasets, sizeof (dsl_dataset_t),
+ offsetof(dsl_dataset_t, ds_synced_link));
tx = dmu_tx_create_assigned(dp, txg);
- dp->dp_read_overhead = 0;
- start = gethrtime();
-
+ /*
+ * Write out all dirty blocks of dirty datasets.
+ */
zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
- while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg))) {
+ while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) {
/*
* We must not sync any non-MOS datasets twice, because
* we may have taken a snapshot of them. However, we
* may sync newly-created datasets on pass 2.
*/
ASSERT(!list_link_active(&ds->ds_synced_link));
- list_insert_tail(&dp->dp_synced_datasets, ds);
+ list_insert_tail(&synced_datasets, ds);
dsl_dataset_sync(ds, zio, tx);
}
- DTRACE_PROBE(pool_sync__1setup);
- err = zio_wait(zio);
+ VERIFY0(zio_wait(zio));
- write_time = gethrtime() - start;
- ASSERT(err == 0);
- DTRACE_PROBE(pool_sync__2rootzio);
+ /*
+ * We have written all of the accounted dirty data, so our
+ * dp_space_towrite should now be zero. However, some seldom-used
+ * code paths do not adhere to this (e.g. dbuf_undirty(), also
+ * rounding error in dbuf_write_physdone).
+ * Shore up the accounting of any dirtied space now.
+ */
+ dsl_pool_undirty_space(dp, dp->dp_dirty_pertxg[txg & TXG_MASK], txg);
- for (ds = list_head(&dp->dp_synced_datasets); ds;
- ds = list_next(&dp->dp_synced_datasets, ds))
+ /*
+ * After the data blocks have been written (ensured by the zio_wait()
+ * above), update the user/group space accounting.
+ */
+ for (ds = list_head(&synced_datasets); ds != NULL;
+ ds = list_next(&synced_datasets, ds)) {
dmu_objset_do_userquota_updates(ds->ds_objset, tx);
+ }
/*
* Sync the datasets again to push out the changes due to
* userspace updates. This must be done before we process the
- * sync tasks, because that could cause a snapshot of a dataset
- * whose ds_bp will be rewritten when we do this 2nd sync.
+ * sync tasks, so that any snapshots will have the correct
+ * user accounting information (and we won't get confused
+ * about which blocks are part of the snapshot).
*/
zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
- while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg))) {
+ while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) {
ASSERT(list_link_active(&ds->ds_synced_link));
dmu_buf_rele(ds->ds_dbuf, ds);
dsl_dataset_sync(ds, zio, tx);
}
- err = zio_wait(zio);
+ VERIFY0(zio_wait(zio));
/*
- * Move dead blocks from the pending deadlist to the on-disk
- * deadlist.
+ * Now that the datasets have been completely synced, we can
+ * clean up our in-memory structures accumulated while syncing:
+ *
+ * - move dead blocks from the pending deadlist to the on-disk deadlist
+ * - release hold from dsl_dataset_dirty()
*/
- for (ds = list_head(&dp->dp_synced_datasets); ds;
- ds = list_next(&dp->dp_synced_datasets, ds)) {
+ while ((ds = list_remove_head(&synced_datasets)) != NULL) {
+ ASSERTV(objset_t *os = ds->ds_objset);
bplist_iterate(&ds->ds_pending_deadlist,
deadlist_enqueue_cb, &ds->ds_deadlist, tx);
+ ASSERT(!dmu_objset_is_dirty(os, txg));
+ dmu_buf_rele(ds->ds_dbuf, ds);
}
- while ((dstg = txg_list_remove(&dp->dp_sync_tasks, txg))) {
- /*
- * No more sync tasks should have been added while we
- * were syncing.
- */
- ASSERT(spa_sync_pass(dp->dp_spa) == 1);
- dsl_sync_task_group_sync(dstg, tx);
+ while ((dd = txg_list_remove(&dp->dp_dirty_dirs, txg)) != NULL) {
+ dsl_dir_sync(dd, tx);
}
- DTRACE_PROBE(pool_sync__3task);
- start = gethrtime();
- while ((dd = txg_list_remove(&dp->dp_dirty_dirs, txg)))
- dsl_dir_sync(dd, tx);
- write_time += gethrtime() - start;
+ /*
+ * The MOS's space is accounted for in the pool/$MOS
+ * (dp_mos_dir). We can't modify the mos while we're syncing
+ * it, so we remember the deltas and apply them here.
+ */
+ if (dp->dp_mos_used_delta != 0 || dp->dp_mos_compressed_delta != 0 ||
+ dp->dp_mos_uncompressed_delta != 0) {
+ dsl_dir_diduse_space(dp->dp_mos_dir, DD_USED_HEAD,
+ dp->dp_mos_used_delta,
+ dp->dp_mos_compressed_delta,
+ dp->dp_mos_uncompressed_delta, tx);
+ dp->dp_mos_used_delta = 0;
+ dp->dp_mos_compressed_delta = 0;
+ dp->dp_mos_uncompressed_delta = 0;
+ }
- start = gethrtime();
if (list_head(&mos->os_dirty_dnodes[txg & TXG_MASK]) != NULL ||
list_head(&mos->os_free_dnodes[txg & TXG_MASK]) != NULL) {
- zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
- dmu_objset_sync(mos, zio, tx);
- err = zio_wait(zio);
- ASSERT(err == 0);
- dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
- spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
+ dsl_pool_sync_mos(dp, tx);
}
- write_time += gethrtime() - start;
- DTRACE_PROBE2(pool_sync__4io, hrtime_t, write_time,
- hrtime_t, dp->dp_read_overhead);
- write_time -= dp->dp_read_overhead;
-
- dmu_tx_commit(tx);
-
- dp->dp_space_towrite[txg & TXG_MASK] = 0;
- ASSERT(dp->dp_tempreserved[txg & TXG_MASK] == 0);
/*
- * If the write limit max has not been explicitly set, set it
- * to a fraction of available physical memory (default 1/8th).
- * Note that we must inflate the limit because the spa
- * inflates write sizes to account for data replication.
- * Check this each sync phase to catch changing memory size.
+ * If we modify a dataset in the same txg that we want to destroy it,
+ * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it.
+ * dsl_dir_destroy_check() will fail if there are unexpected holds.
+ * Therefore, we want to sync the MOS (thus syncing the dd_dbuf
+ * and clearing the hold on it) before we process the sync_tasks.
+ * The MOS data dirtied by the sync_tasks will be synced on the next
+ * pass.
*/
- if (physmem != old_physmem && zfs_write_limit_shift) {
- mutex_enter(&zfs_write_limit_lock);
- old_physmem = physmem;
- zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift;
- zfs_write_limit_inflated = MAX(zfs_write_limit_min,
- spa_get_asize(dp->dp_spa, zfs_write_limit_max));
- mutex_exit(&zfs_write_limit_lock);
+ if (!txg_list_empty(&dp->dp_sync_tasks, txg)) {
+ dsl_sync_task_t *dst;
+ /*
+ * No more sync tasks should have been added while we
+ * were syncing.
+ */
+ ASSERT3U(spa_sync_pass(dp->dp_spa), ==, 1);
+ while ((dst = txg_list_remove(&dp->dp_sync_tasks, txg)) != NULL)
+ dsl_sync_task_sync(dst, tx);
}
- /*
- * Attempt to keep the sync time consistent by adjusting the
- * amount of write traffic allowed into each transaction group.
- * Weight the throughput calculation towards the current value:
- * thru = 3/4 old_thru + 1/4 new_thru
- *
- * Note: write_time is in nanosecs, so write_time/MICROSEC
- * yields millisecs
- */
- ASSERT(zfs_write_limit_min > 0);
- if (data_written > zfs_write_limit_min / 8 && write_time > MICROSEC) {
- uint64_t throughput = data_written / (write_time / MICROSEC);
-
- if (dp->dp_throughput)
- dp->dp_throughput = throughput / 4 +
- 3 * dp->dp_throughput / 4;
- else
- dp->dp_throughput = throughput;
- dp->dp_write_limit = MIN(zfs_write_limit_inflated,
- MAX(zfs_write_limit_min,
- dp->dp_throughput * zfs_txg_synctime_ms));
- }
+ dmu_tx_commit(tx);
+
+ DTRACE_PROBE2(dsl_pool_sync__done, dsl_pool_t *dp, dp, uint64_t, txg);
}
void
dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg)
{
- dsl_dataset_t *ds;
- objset_t *os;
+ zilog_t *zilog;
- while ((ds = list_head(&dp->dp_synced_datasets))) {
- list_remove(&dp->dp_synced_datasets, ds);
- os = ds->ds_objset;
- zil_clean(os->os_zil, txg);
- ASSERT(!dmu_objset_is_dirty(os, txg));
- dmu_buf_rele(ds->ds_dbuf, ds);
+ while ((zilog = txg_list_remove(&dp->dp_dirty_zilogs, txg))) {
+ dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
+ zil_clean(zilog, txg);
+ ASSERT(!dmu_objset_is_dirty(zilog->zl_os, txg));
+ dmu_buf_rele(ds->ds_dbuf, zilog);
}
ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg));
}
return (space - resv);
}
-int
-dsl_pool_tempreserve_space(dsl_pool_t *dp, uint64_t space, dmu_tx_t *tx)
+boolean_t
+dsl_pool_need_dirty_delay(dsl_pool_t *dp)
{
- uint64_t reserved = 0;
- uint64_t write_limit = (zfs_write_limit_override ?
- zfs_write_limit_override : dp->dp_write_limit);
-
- if (zfs_no_write_throttle) {
- atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK],
- space);
- return (0);
- }
+ uint64_t delay_min_bytes =
+ zfs_dirty_data_max * zfs_delay_min_dirty_percent / 100;
+ boolean_t rv;
- /*
- * Check to see if we have exceeded the maximum allowed IO for
- * this transaction group. We can do this without locks since
- * a little slop here is ok. Note that we do the reserved check
- * with only half the requested reserve: this is because the
- * reserve requests are worst-case, and we really don't want to
- * throttle based off of worst-case estimates.
- */
- if (write_limit > 0) {
- reserved = dp->dp_space_towrite[tx->tx_txg & TXG_MASK]
- + dp->dp_tempreserved[tx->tx_txg & TXG_MASK] / 2;
-
- if (reserved && reserved > write_limit) {
- DMU_TX_STAT_BUMP(dmu_tx_write_limit);
- return (ERESTART);
- }
- }
-
- atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], space);
-
- /*
- * If this transaction group is over 7/8ths capacity, delay
- * the caller 1 clock tick. This will slow down the "fill"
- * rate until the sync process can catch up with us.
- */
- if (reserved && reserved > (write_limit - (write_limit >> 3)))
- txg_delay(dp, tx->tx_txg, 1);
-
- return (0);
+ mutex_enter(&dp->dp_lock);
+ if (dp->dp_dirty_total > zfs_dirty_data_sync)
+ txg_kick(dp);
+ rv = (dp->dp_dirty_total > delay_min_bytes);
+ mutex_exit(&dp->dp_lock);
+ return (rv);
}
void
-dsl_pool_tempreserve_clear(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
+dsl_pool_dirty_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
{
- ASSERT(dp->dp_tempreserved[tx->tx_txg & TXG_MASK] >= space);
- atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], -space);
+ if (space > 0) {
+ mutex_enter(&dp->dp_lock);
+ dp->dp_dirty_pertxg[tx->tx_txg & TXG_MASK] += space;
+ dsl_pool_dirty_delta(dp, space);
+ mutex_exit(&dp->dp_lock);
+ }
}
void
-dsl_pool_memory_pressure(dsl_pool_t *dp)
+dsl_pool_undirty_space(dsl_pool_t *dp, int64_t space, uint64_t txg)
{
- uint64_t space_inuse = 0;
- int i;
-
- if (dp->dp_write_limit == zfs_write_limit_min)
+ ASSERT3S(space, >=, 0);
+ if (space == 0)
return;
- for (i = 0; i < TXG_SIZE; i++) {
- space_inuse += dp->dp_space_towrite[i];
- space_inuse += dp->dp_tempreserved[i];
- }
- dp->dp_write_limit = MAX(zfs_write_limit_min,
- MIN(dp->dp_write_limit, space_inuse / 4));
-}
-
-void
-dsl_pool_willuse_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
-{
- if (space > 0) {
- mutex_enter(&dp->dp_lock);
- dp->dp_space_towrite[tx->tx_txg & TXG_MASK] += space;
- mutex_exit(&dp->dp_lock);
+ mutex_enter(&dp->dp_lock);
+ if (dp->dp_dirty_pertxg[txg & TXG_MASK] < space) {
+ /* XXX writing something we didn't dirty? */
+ space = dp->dp_dirty_pertxg[txg & TXG_MASK];
}
+ ASSERT3U(dp->dp_dirty_pertxg[txg & TXG_MASK], >=, space);
+ dp->dp_dirty_pertxg[txg & TXG_MASK] -= space;
+ ASSERT3U(dp->dp_dirty_total, >=, space);
+ dsl_pool_dirty_delta(dp, -space);
+ mutex_exit(&dp->dp_lock);
}
/* ARGSUSED */
static int
-upgrade_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
+upgrade_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
{
dmu_tx_t *tx = arg;
dsl_dataset_t *ds, *prev = NULL;
int err;
- dsl_pool_t *dp = spa_get_dsl(spa);
- err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
+ err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
if (err)
return (err);
* The $ORIGIN can't have any data, or the accounting
* will be wrong.
*/
- ASSERT(prev->ds_phys->ds_bp.blk_birth == 0);
+ ASSERT0(prev->ds_phys->ds_bp.blk_birth);
/* The origin doesn't get attached to itself */
if (ds->ds_object == prev->ds_object) {
if (ds->ds_phys->ds_next_snap_obj == 0) {
ASSERT(ds->ds_prev == NULL);
- VERIFY(0 == dsl_dataset_hold_obj(dp,
+ VERIFY0(dsl_dataset_hold_obj(dp,
ds->ds_phys->ds_prev_snap_obj, ds, &ds->ds_prev));
}
}
- ASSERT(ds->ds_dir->dd_phys->dd_origin_obj == prev->ds_object);
- ASSERT(ds->ds_phys->ds_prev_snap_obj == prev->ds_object);
+ ASSERT3U(ds->ds_dir->dd_phys->dd_origin_obj, ==, prev->ds_object);
+ ASSERT3U(ds->ds_phys->ds_prev_snap_obj, ==, prev->ds_object);
if (prev->ds_phys->ds_next_clones_obj == 0) {
dmu_buf_will_dirty(prev->ds_dbuf, tx);
zap_create(dp->dp_meta_objset,
DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
}
- VERIFY(0 == zap_add_int(dp->dp_meta_objset,
+ VERIFY0(zap_add_int(dp->dp_meta_objset,
prev->ds_phys->ds_next_clones_obj, ds->ds_object, tx));
dsl_dataset_rele(ds, FTAG);
ASSERT(dmu_tx_is_syncing(tx));
ASSERT(dp->dp_origin_snap != NULL);
- VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL, upgrade_clones_cb,
+ VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj, upgrade_clones_cb,
tx, DS_FIND_CHILDREN));
}
/* ARGSUSED */
static int
-upgrade_dir_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
+upgrade_dir_clones_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
{
dmu_tx_t *tx = arg;
- dsl_dataset_t *ds;
- dsl_pool_t *dp = spa_get_dsl(spa);
objset_t *mos = dp->dp_meta_objset;
- VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
-
- if (ds->ds_dir->dd_phys->dd_origin_obj) {
+ if (ds->ds_dir->dd_phys->dd_origin_obj != 0) {
dsl_dataset_t *origin;
- VERIFY3U(0, ==, dsl_dataset_hold_obj(dp,
+ VERIFY0(dsl_dataset_hold_obj(dp,
ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &origin));
if (origin->ds_dir->dd_phys->dd_clones == 0) {
DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
}
- VERIFY3U(0, ==, zap_add_int(dp->dp_meta_objset,
- origin->ds_dir->dd_phys->dd_clones, dsobj, tx));
+ VERIFY0(zap_add_int(dp->dp_meta_objset,
+ origin->ds_dir->dd_phys->dd_clones, ds->ds_object, tx));
dsl_dataset_rele(origin, FTAG);
}
-
- dsl_dataset_rele(ds, FTAG);
return (0);
}
ASSERT(dmu_tx_is_syncing(tx));
(void) dsl_dir_create_sync(dp, dp->dp_root_dir, FREE_DIR_NAME, tx);
- VERIFY(0 == dsl_pool_open_special_dir(dp,
+ VERIFY0(dsl_pool_open_special_dir(dp,
FREE_DIR_NAME, &dp->dp_free_dir));
/*
*/
obj = dmu_object_alloc(dp->dp_meta_objset, DMU_OT_BPOBJ,
SPA_MAXBLOCKSIZE, DMU_OT_BPOBJ_HDR, sizeof (bpobj_phys_t), tx);
- VERIFY3U(0, ==, zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+ VERIFY0(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx));
- VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
- dp->dp_meta_objset, obj));
+ VERIFY0(bpobj_open(&dp->dp_free_bpobj, dp->dp_meta_objset, obj));
- VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL,
+ VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
upgrade_dir_clones_cb, tx, DS_FIND_CHILDREN));
}
ASSERT(dmu_tx_is_syncing(tx));
ASSERT(dp->dp_origin_snap == NULL);
+ ASSERT(rrw_held(&dp->dp_config_rwlock, RW_WRITER));
/* create the origin dir, ds, & snap-ds */
- rw_enter(&dp->dp_config_rwlock, RW_WRITER);
dsobj = dsl_dataset_create_sync(dp->dp_root_dir, ORIGIN_DIR_NAME,
NULL, 0, kcred, tx);
- VERIFY(0 == dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
- dsl_dataset_snapshot_sync(ds, ORIGIN_DIR_NAME, tx);
- VERIFY(0 == dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
+ VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
+ dsl_dataset_snapshot_sync_impl(ds, ORIGIN_DIR_NAME, tx);
+ VERIFY0(dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
dp, &dp->dp_origin_snap));
dsl_dataset_rele(ds, FTAG);
- rw_exit(&dp->dp_config_rwlock);
}
taskq_t *
zap_cursor_t zc;
objset_t *mos = dp->dp_meta_objset;
uint64_t zapobj = dp->dp_tmp_userrefs_obj;
+ nvlist_t *holds;
if (zapobj == 0)
return;
ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
+ holds = fnvlist_alloc();
+
for (zap_cursor_init(&zc, mos, zapobj);
zap_cursor_retrieve(&zc, &za) == 0;
zap_cursor_advance(&zc)) {
char *htag;
- uint64_t dsobj;
+ nvlist_t *tags;
htag = strchr(za.za_name, '-');
*htag = '\0';
++htag;
- dsobj = strtonum(za.za_name, NULL);
- (void) dsl_dataset_user_release_tmp(dp, dsobj, htag, B_FALSE);
+ if (nvlist_lookup_nvlist(holds, za.za_name, &tags) != 0) {
+ tags = fnvlist_alloc();
+ fnvlist_add_boolean(tags, htag);
+ fnvlist_add_nvlist(holds, za.za_name, tags);
+ fnvlist_free(tags);
+ } else {
+ fnvlist_add_boolean(tags, htag);
+ }
}
+ dsl_dataset_user_release_tmp(dp, holds);
+ fnvlist_free(holds);
zap_cursor_fini(&zc);
}
static int
dsl_pool_user_hold_rele_impl(dsl_pool_t *dp, uint64_t dsobj,
- const char *tag, uint64_t *now, dmu_tx_t *tx, boolean_t holding)
+ const char *tag, uint64_t now, dmu_tx_t *tx, boolean_t holding)
{
objset_t *mos = dp->dp_meta_objset;
uint64_t zapobj = dp->dp_tmp_userrefs_obj;
dsl_pool_user_hold_create_obj(dp, tx);
zapobj = dp->dp_tmp_userrefs_obj;
} else {
- return (ENOENT);
+ return (SET_ERROR(ENOENT));
}
}
name = kmem_asprintf("%llx-%s", (u_longlong_t)dsobj, tag);
if (holding)
- error = zap_add(mos, zapobj, name, 8, 1, now, tx);
+ error = zap_add(mos, zapobj, name, 8, 1, &now, tx);
else
error = zap_remove(mos, zapobj, name, tx);
strfree(name);
*/
int
dsl_pool_user_hold(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
- uint64_t *now, dmu_tx_t *tx)
+ uint64_t now, dmu_tx_t *tx)
{
return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, now, tx, B_TRUE));
}
dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
dmu_tx_t *tx)
{
- return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, NULL,
+ return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, 0,
tx, B_FALSE));
}
+/*
+ * DSL Pool Configuration Lock
+ *
+ * The dp_config_rwlock protects against changes to DSL state (e.g. dataset
+ * creation / destruction / rename / property setting). It must be held for
+ * read to hold a dataset or dsl_dir. I.e. you must call
+ * dsl_pool_config_enter() or dsl_pool_hold() before calling
+ * dsl_{dataset,dir}_hold{_obj}. In most circumstances, the dp_config_rwlock
+ * must be held continuously until all datasets and dsl_dirs are released.
+ *
+ * The only exception to this rule is that if a "long hold" is placed on
+ * a dataset, then the dp_config_rwlock may be dropped while the dataset
+ * is still held. The long hold will prevent the dataset from being
+ * destroyed -- the destroy will fail with EBUSY. A long hold can be
+ * obtained by calling dsl_dataset_long_hold(), or by "owning" a dataset
+ * (by calling dsl_{dataset,objset}_{try}own{_obj}).
+ *
+ * Legitimate long-holders (including owners) should be long-running, cancelable
+ * tasks that should cause "zfs destroy" to fail. This includes DMU
+ * consumers (i.e. a ZPL filesystem being mounted or ZVOL being open),
+ * "zfs send", and "zfs diff". There are several other long-holders whose
+ * uses are suboptimal (e.g. "zfs promote", and zil_suspend()).
+ *
+ * The usual formula for long-holding would be:
+ * dsl_pool_hold()
+ * dsl_dataset_hold()
+ * ... perform checks ...
+ * dsl_dataset_long_hold()
+ * dsl_pool_rele()
+ * ... perform long-running task ...
+ * dsl_dataset_long_rele()
+ * dsl_dataset_rele()
+ *
+ * Note that when the long hold is released, the dataset is still held but
+ * the pool is not held. The dataset may change arbitrarily during this time
+ * (e.g. it could be destroyed). Therefore you shouldn't do anything to the
+ * dataset except release it.
+ *
+ * User-initiated operations (e.g. ioctls, zfs_ioc_*()) are either read-only
+ * or modifying operations.
+ *
+ * Modifying operations should generally use dsl_sync_task(). The synctask
+ * infrastructure enforces proper locking strategy with respect to the
+ * dp_config_rwlock. See the comment above dsl_sync_task() for details.
+ *
+ * Read-only operations will manually hold the pool, then the dataset, obtain
+ * information from the dataset, then release the pool and dataset.
+ * dmu_objset_{hold,rele}() are convenience routines that also do the pool
+ * hold/rele.
+ */
+
+int
+dsl_pool_hold(const char *name, void *tag, dsl_pool_t **dp)
+{
+ spa_t *spa;
+ int error;
+
+ error = spa_open(name, &spa, tag);
+ if (error == 0) {
+ *dp = spa_get_dsl(spa);
+ dsl_pool_config_enter(*dp, tag);
+ }
+ return (error);
+}
+
+void
+dsl_pool_rele(dsl_pool_t *dp, void *tag)
+{
+ dsl_pool_config_exit(dp, tag);
+ spa_close(dp->dp_spa, tag);
+}
+
+void
+dsl_pool_config_enter(dsl_pool_t *dp, void *tag)
+{
+ /*
+ * We use a "reentrant" reader-writer lock, but not reentrantly.
+ *
+ * The rrwlock can (with the track_all flag) track all reading threads,
+ * which is very useful for debugging which code path failed to release
+ * the lock, and for verifying that the *current* thread does hold
+ * the lock.
+ *
+ * (Unlike a rwlock, which knows that N threads hold it for
+ * read, but not *which* threads, so rw_held(RW_READER) returns TRUE
+ * if any thread holds it for read, even if this thread doesn't).
+ */
+ ASSERT(!rrw_held(&dp->dp_config_rwlock, RW_READER));
+ rrw_enter(&dp->dp_config_rwlock, RW_READER, tag);
+}
+
+void
+dsl_pool_config_exit(dsl_pool_t *dp, void *tag)
+{
+ rrw_exit(&dp->dp_config_rwlock, tag);
+}
+
+boolean_t
+dsl_pool_config_held(dsl_pool_t *dp)
+{
+ return (RRW_LOCK_HELD(&dp->dp_config_rwlock));
+}
+
#if defined(_KERNEL) && defined(HAVE_SPL)
-module_param(zfs_no_write_throttle, int, 0644);
-MODULE_PARM_DESC(zfs_no_write_throttle, "Disable write throttling");
+EXPORT_SYMBOL(dsl_pool_config_enter);
+EXPORT_SYMBOL(dsl_pool_config_exit);
-module_param(zfs_write_limit_shift, int, 0444);
-MODULE_PARM_DESC(zfs_write_limit_shift, "log2(fraction of memory) per txg");
+/* zfs_dirty_data_max_percent only applied at module load in arc_init(). */
+module_param(zfs_dirty_data_max_percent, int, 0444);
+MODULE_PARM_DESC(zfs_dirty_data_max_percent, "percent of ram can be dirty");
-module_param(zfs_txg_synctime_ms, int, 0644);
-MODULE_PARM_DESC(zfs_txg_synctime_ms, "Target milliseconds between txg sync");
+/* zfs_dirty_data_max_max_percent only applied at module load in arc_init(). */
+module_param(zfs_dirty_data_max_max_percent, int, 0444);
+MODULE_PARM_DESC(zfs_dirty_data_max_max_percent,
+ "zfs_dirty_data_max upper bound as % of RAM");
-module_param(zfs_txg_history, int, 0644);
-MODULE_PARM_DESC(zfs_txg_history, "Historic statistics for the last N txgs");
+module_param(zfs_delay_min_dirty_percent, int, 0644);
+MODULE_PARM_DESC(zfs_delay_min_dirty_percent, "transaction delay threshold");
-module_param(zfs_write_limit_min, ulong, 0444);
-MODULE_PARM_DESC(zfs_write_limit_min, "Min txg write limit");
+module_param(zfs_dirty_data_max, ulong, 0644);
+MODULE_PARM_DESC(zfs_dirty_data_max, "determines the dirty space limit");
-module_param(zfs_write_limit_max, ulong, 0444);
-MODULE_PARM_DESC(zfs_write_limit_max, "Max txg write limit");
+/* zfs_dirty_data_max_max only applied at module load in arc_init(). */
+module_param(zfs_dirty_data_max_max, ulong, 0444);
+MODULE_PARM_DESC(zfs_dirty_data_max_max,
+ "zfs_dirty_data_max upper bound in bytes");
-module_param(zfs_write_limit_inflated, ulong, 0444);
-MODULE_PARM_DESC(zfs_write_limit_inflated, "Inflated txg write limit");
+module_param(zfs_dirty_data_sync, ulong, 0644);
+MODULE_PARM_DESC(zfs_dirty_data_sync, "sync txg when this much dirty data");
-module_param(zfs_write_limit_override, ulong, 0444);
-MODULE_PARM_DESC(zfs_write_limit_override, "Override txg write limit");
+module_param(zfs_delay_scale, ulong, 0644);
+MODULE_PARM_DESC(zfs_delay_scale, "how quickly delay approaches infinity");
#endif
projects / mirror_zfs.git / blobdiff