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mirror_zfs/module/zfs/ddt.c
Tino Reichardt 1713aa7b4d
Remove set but not used variable in ddt.c (#16522) 
module/zfs/ddt.c:2612:6: error: variable 'total' set but not used

Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
2024-09-10 12:46:50 -07:00

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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or https://opensource.org/licenses/CDDL-1.0.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2016 by Delphix. All rights reserved.
* Copyright (c) 2022 by Pawel Jakub Dawidek
* Copyright (c) 2019, 2023, Klara Inc.
*/
#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/zio.h>
#include <sys/ddt.h>
#include <sys/ddt_impl.h>
#include <sys/zap.h>
#include <sys/dmu_tx.h>
#include <sys/arc.h>
#include <sys/dsl_pool.h>
#include <sys/zio_checksum.h>
#include <sys/dsl_scan.h>
#include <sys/abd.h>
#include <sys/zfeature.h>
/*
* # DDT: Deduplication tables
*
* The dedup subsystem provides block-level deduplication. When enabled, blocks
* to be written will have the dedup (D) bit set, which causes them to be
* tracked in a "dedup table", or DDT. If a block has been seen before (exists
* in the DDT), instead of being written, it will instead be made to reference
* the existing on-disk data, and a refcount bumped in the DDT instead.
*
* ## Dedup tables and entries
*
* Conceptually, a DDT is a dictionary or map. Each entry has a "key"
* (ddt_key_t) made up a block's checksum and certian properties, and a "value"
* (one or more ddt_phys_t) containing valid DVAs for the block's data, birth
* time and refcount. Together these are enough to track references to a
* specific block, to build a valid block pointer to reference that block (for
* freeing, scrubbing, etc), and to fill a new block pointer with the missing
* pieces to make it seem like it was written.
*
* There's a single DDT (ddt_t) for each checksum type, held in spa_ddt[].
* Within each DDT, there can be multiple storage "types" (ddt_type_t, on-disk
* object data formats, each with their own implementations) and "classes"
* (ddt_class_t, instance of a storage type object, for entries with a specific
* characteristic). An entry (key) will only ever exist on one of these objects
* at any given time, but may be moved from one to another if their type or
* class changes.
*
* The DDT is driven by the write IO pipeline (zio_ddt_write()). When a block
* is to be written, before DVAs have been allocated, ddt_lookup() is called to
* see if the block has been seen before. If its not found, the write proceeds
* as normal, and after it succeeds, a new entry is created. If it is found, we
* fill the BP with the DVAs from the entry, increment the refcount and cause
* the write IO to return immediately.
*
* Traditionally, each ddt_phys_t slot in the entry represents a separate dedup
* block for the same content/checksum. The slot is selected based on the
* zp_copies parameter the block is written with, that is, the number of DVAs
* in the block. The "ditto" slot (DDT_PHYS_DITTO) used to be used for
* now-removed "dedupditto" feature. These are no longer written, and will be
* freed if encountered on old pools.
*
* If the "fast_dedup" feature is enabled, new dedup tables will be created
* with the "flat phys" option. In this mode, there is only one ddt_phys_t
* slot. If a write is issued for an entry that exists, but has fewer DVAs,
* then only as many new DVAs are allocated and written to make up the
* shortfall. The existing entry is then extended (ddt_phys_extend()) with the
* new DVAs.
*
* ## Lifetime of an entry
*
* A DDT can be enormous, and typically is not held in memory all at once.
* Instead, the changes to an entry are tracked in memory, and written down to
* disk at the end of each txg.
*
* A "live" in-memory entry (ddt_entry_t) is a node on the live tree
* (ddt_tree). At the start of a txg, ddt_tree is empty. When an entry is
* required for IO, ddt_lookup() is called. If an entry already exists on
* ddt_tree, it is returned. Otherwise, a new one is created, and the
* type/class objects for the DDT are searched for that key. If its found, its
* value is copied into the live entry. If not, an empty entry is created.
*
* The live entry will be modified during the txg, usually by modifying the
* refcount, but sometimes by adding or updating DVAs. At the end of the txg
* (during spa_sync()), type and class are recalculated for entry (see
* ddt_sync_entry()), and the entry is written to the appropriate storage
* object and (if necessary), removed from an old one. ddt_tree is cleared and
* the next txg can start.
*
* ## Dedup quota
*
* A maximum size for all DDTs on the pool can be set with the
* dedup_table_quota property. This is determined in ddt_over_quota() and
* enforced during ddt_lookup(). If the pool is at or over its quota limit,
* ddt_lookup() will only return entries for existing blocks, as updates are
* still possible. New entries will not be created; instead, ddt_lookup() will
* return NULL. In response, the DDT write stage (zio_ddt_write()) will remove
* the D bit on the block and reissue the IO as a regular write. The block will
* not be deduplicated.
*
* Note that this is based on the on-disk size of the dedup store. Reclaiming
* this space after deleting entries relies on the ZAP "shrinking" behaviour,
* without which, no space would be recovered and the DDT would continue to be
* considered "over quota". See zap_shrink_enabled.
*
* ## Dedup table pruning
*
* As a complement to the dedup quota feature, ddtprune allows removal of older
* non-duplicate entries to make room for newer duplicate entries. The amount
* to prune can be based on a target percentage of the unique entries or based
* on the age (i.e., prune unique entry older than N days).
*
* ## Dedup log
*
* Historically, all entries modified on a txg were written back to dedup
* storage objects at the end of every txg. This could cause significant
* overheads, as each entry only takes up a tiny portion of a ZAP leaf node,
* and so required reading the whole node, updating the entry, and writing it
* back. On busy pools, this could add serious IO and memory overheads.
*
* To address this, the dedup log was added. If the "fast_dedup" feature is
* enabled, at the end of each txg, modified entries will be copied to an
* in-memory "log" object (ddt_log_t), and appended to an on-disk log. If the
* same block is requested again, the in-memory object will be checked first,
* and if its there, the entry inflated back onto the live tree without going
* to storage. The on-disk log is only read at pool import time, to reload the
* in-memory log.
*
* Each txg, some amount of the in-memory log will be flushed out to a DDT
* storage object (ie ZAP) as normal. OpenZFS will try hard to flush enough to
* keep up with the rate of change on dedup entries, but not so much that it
* would impact overall throughput, and not using too much memory. See the
* zfs_dedup_log_* tuneables in zfs(4) for more details.
*
* ## Repair IO
*
* If a read on a dedup block fails, but there are other copies of the block in
* the other ddt_phys_t slots, reads will be issued for those instead
* (zio_ddt_read_start()). If one of those succeeds, the read is returned to
* the caller, and a copy is stashed on the entry's dde_repair_abd.
*
* During the end-of-txg sync, any entries with a dde_repair_abd get a
* "rewrite" write issued for the original block pointer, with the data read
* from the alternate block. If the block is actually damaged, this will invoke
* the pool's "self-healing" mechanism, and repair the block.
*
* If the "fast_dedup" feature is enabled, the "flat phys" option will be in
* use, so there is only ever one ddt_phys_t slot. The repair process will
* still happen in this case, though it is unlikely to succeed as there will
* usually be no other equivalent blocks to fall back on (though there might
* be, if this was an early version of a dedup'd block that has since been
* extended).
*
* Note that this repair mechanism is in addition to and separate from the
* regular OpenZFS scrub and self-healing mechanisms.
*
* ## Scanning (scrub/resilver)
*
* If dedup is active, the scrub machinery will walk the dedup table first, and
* scrub all blocks with refcnt > 1 first. After that it will move on to the
* regular top-down scrub, and exclude the refcnt > 1 blocks when it sees them.
* In this way, heavily deduplicated blocks are only scrubbed once. See the
* commentary on dsl_scan_ddt() for more details.
*
* Walking the DDT is done via ddt_walk(). The current position is stored in a
* ddt_bookmark_t, which represents a stable position in the storage object.
* This bookmark is stored by the scan machinery, and must reference the same
* position on the object even if the object changes, the pool is exported, or
* OpenZFS is upgraded.
*
* If the "fast_dedup" feature is enabled and the table has a log, the scan
* cannot begin until entries on the log are flushed, as the on-disk log has no
* concept of a "stable position". Instead, the log flushing process will enter
* a more aggressive mode, to flush out as much as is necesary as soon as
* possible, in order to begin the scan as soon as possible.
*
* ## Interaction with block cloning
*
* If block cloning and dedup are both enabled on a pool, BRT will look for the
* dedup bit on an incoming block pointer. If set, it will call into the DDT
* (ddt_addref()) to add a reference to the block, instead of adding a
* reference to the BRT. See brt_pending_apply().
*/
/*
* These are the only checksums valid for dedup. They must match the list
* from dedup_table in zfs_prop.c
*/
#define DDT_CHECKSUM_VALID(c) \
(c == ZIO_CHECKSUM_SHA256 || c == ZIO_CHECKSUM_SHA512 || \
c == ZIO_CHECKSUM_SKEIN || c == ZIO_CHECKSUM_EDONR || \
c == ZIO_CHECKSUM_BLAKE3)
static kmem_cache_t *ddt_cache;
static kmem_cache_t *ddt_entry_flat_cache;
static kmem_cache_t *ddt_entry_trad_cache;
#define DDT_ENTRY_FLAT_SIZE (sizeof (ddt_entry_t) + DDT_FLAT_PHYS_SIZE)
#define DDT_ENTRY_TRAD_SIZE (sizeof (ddt_entry_t) + DDT_TRAD_PHYS_SIZE)
#define DDT_ENTRY_SIZE(ddt) \
_DDT_PHYS_SWITCH(ddt, DDT_ENTRY_FLAT_SIZE, DDT_ENTRY_TRAD_SIZE)
/*
* Enable/disable prefetching of dedup-ed blocks which are going to be freed.
*/
int zfs_dedup_prefetch = 0;
/*
* If the dedup class cannot satisfy a DDT allocation, treat as over quota
* for this many TXGs.
*/
uint_t dedup_class_wait_txgs = 5;
/*
* How many DDT prune entries to add to the DDT sync AVL tree.
* Note these addtional entries have a memory footprint of a
* ddt_entry_t (216 bytes).
*/
static uint32_t zfs_ddt_prunes_per_txg = 50000;
/*
* For testing, synthesize aged DDT entries
* (in global scope for ztest)
*/
boolean_t ddt_prune_artificial_age = B_FALSE;
boolean_t ddt_dump_prune_histogram = B_FALSE;
/*
* Don't do more than this many incremental flush passes per txg.
*/
uint_t zfs_dedup_log_flush_passes_max = 8;
/*
* Minimum time to flush per txg.
*/
uint_t zfs_dedup_log_flush_min_time_ms = 1000;
/*
* Minimum entries to flush per txg.
*/
uint_t zfs_dedup_log_flush_entries_min = 1000;
/*
* Number of txgs to average flow rates across.
*/
uint_t zfs_dedup_log_flush_flow_rate_txgs = 10;
static const ddt_ops_t *const ddt_ops[DDT_TYPES] = {
&ddt_zap_ops,
};
static const char *const ddt_class_name[DDT_CLASSES] = {
"ditto",
"duplicate",
"unique",
};
/*
* DDT feature flags automatically enabled for each on-disk version. Note that
* versions >0 cannot exist on disk without SPA_FEATURE_FAST_DEDUP enabled.
*/
static const uint64_t ddt_version_flags[] = {
[DDT_VERSION_LEGACY] = 0,
[DDT_VERSION_FDT] = DDT_FLAG_FLAT | DDT_FLAG_LOG,
};
/* per-DDT kstats */
typedef struct {
/* total lookups and whether they returned new or existing entries */
kstat_named_t dds_lookup;
kstat_named_t dds_lookup_new;
kstat_named_t dds_lookup_existing;
/* entries found on live tree, and if we had to wait for load */
kstat_named_t dds_lookup_live_hit;
kstat_named_t dds_lookup_live_wait;
kstat_named_t dds_lookup_live_miss;
/* entries found on log trees */
kstat_named_t dds_lookup_log_hit;
kstat_named_t dds_lookup_log_active_hit;
kstat_named_t dds_lookup_log_flushing_hit;
kstat_named_t dds_lookup_log_miss;
/* entries found on store objects */
kstat_named_t dds_lookup_stored_hit;
kstat_named_t dds_lookup_stored_miss;
/* number of entries on log trees */
kstat_named_t dds_log_active_entries;
kstat_named_t dds_log_flushing_entries;
/* avg updated/flushed entries per txg */
kstat_named_t dds_log_ingest_rate;
kstat_named_t dds_log_flush_rate;
kstat_named_t dds_log_flush_time_rate;
} ddt_kstats_t;
static const ddt_kstats_t ddt_kstats_template = {
{ "lookup", KSTAT_DATA_UINT64 },
{ "lookup_new", KSTAT_DATA_UINT64 },
{ "lookup_existing", KSTAT_DATA_UINT64 },
{ "lookup_live_hit", KSTAT_DATA_UINT64 },
{ "lookup_live_wait", KSTAT_DATA_UINT64 },
{ "lookup_live_miss", KSTAT_DATA_UINT64 },
{ "lookup_log_hit", KSTAT_DATA_UINT64 },
{ "lookup_log_active_hit", KSTAT_DATA_UINT64 },
{ "lookup_log_flushing_hit", KSTAT_DATA_UINT64 },
{ "lookup_log_miss", KSTAT_DATA_UINT64 },
{ "lookup_stored_hit", KSTAT_DATA_UINT64 },
{ "lookup_stored_miss", KSTAT_DATA_UINT64 },
{ "log_active_entries", KSTAT_DATA_UINT64 },
{ "log_flushing_entries", KSTAT_DATA_UINT64 },
{ "log_ingest_rate", KSTAT_DATA_UINT32 },
{ "log_flush_rate", KSTAT_DATA_UINT32 },
{ "log_flush_time_rate", KSTAT_DATA_UINT32 },
};
#ifdef _KERNEL
#define _DDT_KSTAT_STAT(ddt, stat) \
&((ddt_kstats_t *)(ddt)->ddt_ksp->ks_data)->stat.value.ui64
#define DDT_KSTAT_BUMP(ddt, stat) \
do { atomic_inc_64(_DDT_KSTAT_STAT(ddt, stat)); } while (0)
#define DDT_KSTAT_ADD(ddt, stat, val) \
do { atomic_add_64(_DDT_KSTAT_STAT(ddt, stat), val); } while (0)
#define DDT_KSTAT_SUB(ddt, stat, val) \
do { atomic_sub_64(_DDT_KSTAT_STAT(ddt, stat), val); } while (0)
#define DDT_KSTAT_SET(ddt, stat, val) \
do { atomic_store_64(_DDT_KSTAT_STAT(ddt, stat), val); } while (0)
#define DDT_KSTAT_ZERO(ddt, stat) DDT_KSTAT_SET(ddt, stat, 0)
#else
#define DDT_KSTAT_BUMP(ddt, stat) do {} while (0)
#define DDT_KSTAT_ADD(ddt, stat, val) do {} while (0)
#define DDT_KSTAT_SUB(ddt, stat, val) do {} while (0)
#define DDT_KSTAT_SET(ddt, stat, val) do {} while (0)
#define DDT_KSTAT_ZERO(ddt, stat) do {} while (0)
#endif /* _KERNEL */
static void
ddt_object_create(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
dmu_tx_t *tx)
{
spa_t *spa = ddt->ddt_spa;
objset_t *os = ddt->ddt_os;
uint64_t *objectp = &ddt->ddt_object[type][class];
boolean_t prehash = zio_checksum_table[ddt->ddt_checksum].ci_flags &
ZCHECKSUM_FLAG_DEDUP;
char name[DDT_NAMELEN];
ASSERT3U(ddt->ddt_dir_object, >, 0);
ddt_object_name(ddt, type, class, name);
ASSERT3U(*objectp, ==, 0);
VERIFY0(ddt_ops[type]->ddt_op_create(os, objectp, tx, prehash));
ASSERT3U(*objectp, !=, 0);
ASSERT3U(ddt->ddt_version, !=, DDT_VERSION_UNCONFIGURED);
VERIFY0(zap_add(os, ddt->ddt_dir_object, name, sizeof (uint64_t), 1,
objectp, tx));
VERIFY0(zap_add(os, spa->spa_ddt_stat_object, name,
sizeof (uint64_t), sizeof (ddt_histogram_t) / sizeof (uint64_t),
&ddt->ddt_histogram[type][class], tx));
}
static void
ddt_object_destroy(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
dmu_tx_t *tx)
{
spa_t *spa = ddt->ddt_spa;
objset_t *os = ddt->ddt_os;
uint64_t *objectp = &ddt->ddt_object[type][class];
uint64_t count;
char name[DDT_NAMELEN];
ASSERT3U(ddt->ddt_dir_object, >, 0);
ddt_object_name(ddt, type, class, name);
ASSERT3U(*objectp, !=, 0);
ASSERT(ddt_histogram_empty(&ddt->ddt_histogram[type][class]));
VERIFY0(ddt_object_count(ddt, type, class, &count));
VERIFY0(count);
VERIFY0(zap_remove(os, ddt->ddt_dir_object, name, tx));
VERIFY0(zap_remove(os, spa->spa_ddt_stat_object, name, tx));
VERIFY0(ddt_ops[type]->ddt_op_destroy(os, *objectp, tx));
memset(&ddt->ddt_object_stats[type][class], 0, sizeof (ddt_object_t));
*objectp = 0;
}
static int
ddt_object_load(ddt_t *ddt, ddt_type_t type, ddt_class_t class)
{
ddt_object_t *ddo = &ddt->ddt_object_stats[type][class];
dmu_object_info_t doi;
uint64_t count;
char name[DDT_NAMELEN];
int error;
if (ddt->ddt_dir_object == 0) {
/*
* If we're configured but the containing dir doesn't exist
* yet, then this object can't possibly exist either.
*/
ASSERT3U(ddt->ddt_version, !=, DDT_VERSION_UNCONFIGURED);
return (SET_ERROR(ENOENT));
}
ddt_object_name(ddt, type, class, name);
error = zap_lookup(ddt->ddt_os, ddt->ddt_dir_object, name,
sizeof (uint64_t), 1, &ddt->ddt_object[type][class]);
if (error != 0)
return (error);
error = zap_lookup(ddt->ddt_os, ddt->ddt_spa->spa_ddt_stat_object, name,
sizeof (uint64_t), sizeof (ddt_histogram_t) / sizeof (uint64_t),
&ddt->ddt_histogram[type][class]);
if (error != 0)
return (error);
/*
* Seed the cached statistics.
*/
error = ddt_object_info(ddt, type, class, &doi);
if (error)
return (error);
error = ddt_object_count(ddt, type, class, &count);
if (error)
return (error);
ddo->ddo_count = count;
ddo->ddo_dspace = doi.doi_physical_blocks_512 << 9;
ddo->ddo_mspace = doi.doi_fill_count * doi.doi_data_block_size;
return (0);
}
static void
ddt_object_sync(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
dmu_tx_t *tx)
{
ddt_object_t *ddo = &ddt->ddt_object_stats[type][class];
dmu_object_info_t doi;
uint64_t count;
char name[DDT_NAMELEN];
ddt_object_name(ddt, type, class, name);
VERIFY0(zap_update(ddt->ddt_os, ddt->ddt_spa->spa_ddt_stat_object, name,
sizeof (uint64_t), sizeof (ddt_histogram_t) / sizeof (uint64_t),
&ddt->ddt_histogram[type][class], tx));
/*
* Cache DDT statistics; this is the only time they'll change.
*/
VERIFY0(ddt_object_info(ddt, type, class, &doi));
VERIFY0(ddt_object_count(ddt, type, class, &count));
ddo->ddo_count = count;
ddo->ddo_dspace = doi.doi_physical_blocks_512 << 9;
ddo->ddo_mspace = doi.doi_fill_count * doi.doi_data_block_size;
}
static boolean_t
ddt_object_exists(ddt_t *ddt, ddt_type_t type, ddt_class_t class)
{
return (!!ddt->ddt_object[type][class]);
}
static int
ddt_object_lookup(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
ddt_entry_t *dde)
{
if (!ddt_object_exists(ddt, type, class))
return (SET_ERROR(ENOENT));
return (ddt_ops[type]->ddt_op_lookup(ddt->ddt_os,
ddt->ddt_object[type][class], &dde->dde_key,
dde->dde_phys, DDT_PHYS_SIZE(ddt)));
}
static int
ddt_object_contains(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
const ddt_key_t *ddk)
{
if (!ddt_object_exists(ddt, type, class))
return (SET_ERROR(ENOENT));
return (ddt_ops[type]->ddt_op_contains(ddt->ddt_os,
ddt->ddt_object[type][class], ddk));
}
static void
ddt_object_prefetch(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
const ddt_key_t *ddk)
{
if (!ddt_object_exists(ddt, type, class))
return;
ddt_ops[type]->ddt_op_prefetch(ddt->ddt_os,
ddt->ddt_object[type][class], ddk);
}
static void
ddt_object_prefetch_all(ddt_t *ddt, ddt_type_t type, ddt_class_t class)
{
if (!ddt_object_exists(ddt, type, class))
return;
ddt_ops[type]->ddt_op_prefetch_all(ddt->ddt_os,
ddt->ddt_object[type][class]);
}
static int
ddt_object_update(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
const ddt_lightweight_entry_t *ddlwe, dmu_tx_t *tx)
{
ASSERT(ddt_object_exists(ddt, type, class));
return (ddt_ops[type]->ddt_op_update(ddt->ddt_os,
ddt->ddt_object[type][class], &ddlwe->ddlwe_key,
&ddlwe->ddlwe_phys, DDT_PHYS_SIZE(ddt), tx));
}
static int
ddt_object_remove(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
const ddt_key_t *ddk, dmu_tx_t *tx)
{
ASSERT(ddt_object_exists(ddt, type, class));
return (ddt_ops[type]->ddt_op_remove(ddt->ddt_os,
ddt->ddt_object[type][class], ddk, tx));
}
int
ddt_object_walk(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
uint64_t *walk, ddt_lightweight_entry_t *ddlwe)
{
ASSERT(ddt_object_exists(ddt, type, class));
int error = ddt_ops[type]->ddt_op_walk(ddt->ddt_os,
ddt->ddt_object[type][class], walk, &ddlwe->ddlwe_key,
&ddlwe->ddlwe_phys, DDT_PHYS_SIZE(ddt));
if (error == 0) {
ddlwe->ddlwe_type = type;
ddlwe->ddlwe_class = class;
return (0);
}
return (error);
}
int
ddt_object_count(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
uint64_t *count)
{
ASSERT(ddt_object_exists(ddt, type, class));
return (ddt_ops[type]->ddt_op_count(ddt->ddt_os,
ddt->ddt_object[type][class], count));
}
int
ddt_object_info(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
dmu_object_info_t *doi)
{
if (!ddt_object_exists(ddt, type, class))
return (SET_ERROR(ENOENT));
return (dmu_object_info(ddt->ddt_os, ddt->ddt_object[type][class],
doi));
}
void
ddt_object_name(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
char *name)
{
(void) snprintf(name, DDT_NAMELEN, DMU_POOL_DDT,
zio_checksum_table[ddt->ddt_checksum].ci_name,
ddt_ops[type]->ddt_op_name, ddt_class_name[class]);
}
void
ddt_bp_fill(const ddt_univ_phys_t *ddp, ddt_phys_variant_t v,
blkptr_t *bp, uint64_t txg)
{
ASSERT3U(txg, !=, 0);
ASSERT3U(v, <, DDT_PHYS_NONE);
uint64_t phys_birth;
const dva_t *dvap;
if (v == DDT_PHYS_FLAT) {
phys_birth = ddp->ddp_flat.ddp_phys_birth;
dvap = ddp->ddp_flat.ddp_dva;
} else {
phys_birth = ddp->ddp_trad[v].ddp_phys_birth;
dvap = ddp->ddp_trad[v].ddp_dva;
}
for (int d = 0; d < SPA_DVAS_PER_BP; d++)
bp->blk_dva[d] = dvap[d];
BP_SET_BIRTH(bp, txg, phys_birth);
}
/*
* The bp created via this function may be used for repairs and scrub, but it
* will be missing the salt / IV required to do a full decrypting read.
*/
void
ddt_bp_create(enum zio_checksum checksum, const ddt_key_t *ddk,
const ddt_univ_phys_t *ddp, ddt_phys_variant_t v, blkptr_t *bp)
{
BP_ZERO(bp);
if (ddp != NULL)
ddt_bp_fill(ddp, v, bp, ddt_phys_birth(ddp, v));
bp->blk_cksum = ddk->ddk_cksum;
BP_SET_LSIZE(bp, DDK_GET_LSIZE(ddk));
BP_SET_PSIZE(bp, DDK_GET_PSIZE(ddk));
BP_SET_COMPRESS(bp, DDK_GET_COMPRESS(ddk));
BP_SET_CRYPT(bp, DDK_GET_CRYPT(ddk));
BP_SET_FILL(bp, 1);
BP_SET_CHECKSUM(bp, checksum);
BP_SET_TYPE(bp, DMU_OT_DEDUP);
BP_SET_LEVEL(bp, 0);
BP_SET_DEDUP(bp, 1);
BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
}
void
ddt_key_fill(ddt_key_t *ddk, const blkptr_t *bp)
{
ddk->ddk_cksum = bp->blk_cksum;
ddk->ddk_prop = 0;
ASSERT(BP_IS_ENCRYPTED(bp) || !BP_USES_CRYPT(bp));
DDK_SET_LSIZE(ddk, BP_GET_LSIZE(bp));
DDK_SET_PSIZE(ddk, BP_GET_PSIZE(bp));
DDK_SET_COMPRESS(ddk, BP_GET_COMPRESS(bp));
DDK_SET_CRYPT(ddk, BP_USES_CRYPT(bp));
}
void
ddt_phys_extend(ddt_univ_phys_t *ddp, ddt_phys_variant_t v, const blkptr_t *bp)
{
ASSERT3U(v, <, DDT_PHYS_NONE);
int bp_ndvas = BP_GET_NDVAS(bp);
int ddp_max_dvas = BP_IS_ENCRYPTED(bp) ?
SPA_DVAS_PER_BP - 1 : SPA_DVAS_PER_BP;
dva_t *dvas = (v == DDT_PHYS_FLAT) ?
ddp->ddp_flat.ddp_dva : ddp->ddp_trad[v].ddp_dva;
int s = 0, d = 0;
while (s < bp_ndvas && d < ddp_max_dvas) {
if (DVA_IS_VALID(&dvas[d])) {
d++;
continue;
}
dvas[d] = bp->blk_dva[s];
s++; d++;
}
/*
* If the caller offered us more DVAs than we can fit, something has
* gone wrong in their accounting. zio_ddt_write() should never ask for
* more than we need.
*/
ASSERT3U(s, ==, bp_ndvas);
if (BP_IS_ENCRYPTED(bp))
dvas[2] = bp->blk_dva[2];
if (ddt_phys_birth(ddp, v) == 0) {
if (v == DDT_PHYS_FLAT)
ddp->ddp_flat.ddp_phys_birth = BP_GET_BIRTH(bp);
else
ddp->ddp_trad[v].ddp_phys_birth = BP_GET_BIRTH(bp);
}
}
void
ddt_phys_copy(ddt_univ_phys_t *dst, const ddt_univ_phys_t *src,
ddt_phys_variant_t v)
{
ASSERT3U(v, <, DDT_PHYS_NONE);
if (v == DDT_PHYS_FLAT)
dst->ddp_flat = src->ddp_flat;
else
dst->ddp_trad[v] = src->ddp_trad[v];
}
void
ddt_phys_clear(ddt_univ_phys_t *ddp, ddt_phys_variant_t v)
{
ASSERT3U(v, <, DDT_PHYS_NONE);
if (v == DDT_PHYS_FLAT)
memset(&ddp->ddp_flat, 0, DDT_FLAT_PHYS_SIZE);
else
memset(&ddp->ddp_trad[v], 0, DDT_TRAD_PHYS_SIZE / DDT_PHYS_MAX);
}
static uint64_t
ddt_class_start(void)
{
uint64_t start = gethrestime_sec();
if (ddt_prune_artificial_age) {
/*
* debug aide -- simulate a wider distribution
* so we don't have to wait for an aged DDT
* to test prune.
*/
int range = 1 << 21;
int percent = random_in_range(100);
if (percent < 50) {
range = range >> 4;
} else if (percent > 75) {
range /= 2;
}
start -= random_in_range(range);
}
return (start);
}
void
ddt_phys_addref(ddt_univ_phys_t *ddp, ddt_phys_variant_t v)
{
ASSERT3U(v, <, DDT_PHYS_NONE);
if (v == DDT_PHYS_FLAT)
ddp->ddp_flat.ddp_refcnt++;
else
ddp->ddp_trad[v].ddp_refcnt++;
}
uint64_t
ddt_phys_decref(ddt_univ_phys_t *ddp, ddt_phys_variant_t v)
{
ASSERT3U(v, <, DDT_PHYS_NONE);
uint64_t *refcntp;
if (v == DDT_PHYS_FLAT)
refcntp = &ddp->ddp_flat.ddp_refcnt;
else
refcntp = &ddp->ddp_trad[v].ddp_refcnt;
ASSERT3U(*refcntp, >, 0);
(*refcntp)--;
return (*refcntp);
}
static void
ddt_phys_free(ddt_t *ddt, ddt_key_t *ddk, ddt_univ_phys_t *ddp,
ddt_phys_variant_t v, uint64_t txg)
{
blkptr_t blk;
ddt_bp_create(ddt->ddt_checksum, ddk, ddp, v, &blk);
/*
* We clear the dedup bit so that zio_free() will actually free the
* space, rather than just decrementing the refcount in the DDT.
*/
BP_SET_DEDUP(&blk, 0);
ddt_phys_clear(ddp, v);
zio_free(ddt->ddt_spa, txg, &blk);
}
uint64_t
ddt_phys_birth(const ddt_univ_phys_t *ddp, ddt_phys_variant_t v)
{
ASSERT3U(v, <, DDT_PHYS_NONE);
if (v == DDT_PHYS_FLAT)
return (ddp->ddp_flat.ddp_phys_birth);
else
return (ddp->ddp_trad[v].ddp_phys_birth);
}
int
ddt_phys_dva_count(const ddt_univ_phys_t *ddp, ddt_phys_variant_t v,
boolean_t encrypted)
{
ASSERT3U(v, <, DDT_PHYS_NONE);
const dva_t *dvas = (v == DDT_PHYS_FLAT) ?
ddp->ddp_flat.ddp_dva : ddp->ddp_trad[v].ddp_dva;
return (DVA_IS_VALID(&dvas[0]) +
DVA_IS_VALID(&dvas[1]) +
DVA_IS_VALID(&dvas[2]) * !encrypted);
}
ddt_phys_variant_t
ddt_phys_select(const ddt_t *ddt, const ddt_entry_t *dde, const blkptr_t *bp)
{
if (dde == NULL)
return (DDT_PHYS_NONE);
const ddt_univ_phys_t *ddp = dde->dde_phys;
if (ddt->ddt_flags & DDT_FLAG_FLAT) {
if (DVA_EQUAL(BP_IDENTITY(bp), &ddp->ddp_flat.ddp_dva[0]) &&
BP_GET_BIRTH(bp) == ddp->ddp_flat.ddp_phys_birth) {
return (DDT_PHYS_FLAT);
}
} else /* traditional phys */ {
for (int p = 0; p < DDT_PHYS_MAX; p++) {
if (DVA_EQUAL(BP_IDENTITY(bp),
&ddp->ddp_trad[p].ddp_dva[0]) &&
BP_GET_BIRTH(bp) ==
ddp->ddp_trad[p].ddp_phys_birth) {
return (p);
}
}
}
return (DDT_PHYS_NONE);
}
uint64_t
ddt_phys_refcnt(const ddt_univ_phys_t *ddp, ddt_phys_variant_t v)
{
ASSERT3U(v, <, DDT_PHYS_NONE);
if (v == DDT_PHYS_FLAT)
return (ddp->ddp_flat.ddp_refcnt);
else
return (ddp->ddp_trad[v].ddp_refcnt);
}
uint64_t
ddt_phys_total_refcnt(const ddt_t *ddt, const ddt_univ_phys_t *ddp)
{
uint64_t refcnt = 0;
if (ddt->ddt_flags & DDT_FLAG_FLAT)
refcnt = ddp->ddp_flat.ddp_refcnt;
else
for (int v = DDT_PHYS_SINGLE; v <= DDT_PHYS_TRIPLE; v++)
refcnt += ddp->ddp_trad[v].ddp_refcnt;
return (refcnt);
}
ddt_t *
ddt_select(spa_t *spa, const blkptr_t *bp)
{
ASSERT(DDT_CHECKSUM_VALID(BP_GET_CHECKSUM(bp)));
return (spa->spa_ddt[BP_GET_CHECKSUM(bp)]);
}
void
ddt_enter(ddt_t *ddt)
{
mutex_enter(&ddt->ddt_lock);
}
void
ddt_exit(ddt_t *ddt)
{
mutex_exit(&ddt->ddt_lock);
}
void
ddt_init(void)
{
ddt_cache = kmem_cache_create("ddt_cache",
sizeof (ddt_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
ddt_entry_flat_cache = kmem_cache_create("ddt_entry_flat_cache",
DDT_ENTRY_FLAT_SIZE, 0, NULL, NULL, NULL, NULL, NULL, 0);
ddt_entry_trad_cache = kmem_cache_create("ddt_entry_trad_cache",
DDT_ENTRY_TRAD_SIZE, 0, NULL, NULL, NULL, NULL, NULL, 0);
ddt_log_init();
}
void
ddt_fini(void)
{
ddt_log_fini();
kmem_cache_destroy(ddt_entry_trad_cache);
kmem_cache_destroy(ddt_entry_flat_cache);
kmem_cache_destroy(ddt_cache);
}
static ddt_entry_t *
ddt_alloc(const ddt_t *ddt, const ddt_key_t *ddk)
{
ddt_entry_t *dde;
if (ddt->ddt_flags & DDT_FLAG_FLAT) {
dde = kmem_cache_alloc(ddt_entry_flat_cache, KM_SLEEP);
memset(dde, 0, DDT_ENTRY_FLAT_SIZE);
} else {
dde = kmem_cache_alloc(ddt_entry_trad_cache, KM_SLEEP);
memset(dde, 0, DDT_ENTRY_TRAD_SIZE);
}
cv_init(&dde->dde_cv, NULL, CV_DEFAULT, NULL);
dde->dde_key = *ddk;
return (dde);
}
void
ddt_alloc_entry_io(ddt_entry_t *dde)
{
if (dde->dde_io != NULL)
return;
dde->dde_io = kmem_zalloc(sizeof (ddt_entry_io_t), KM_SLEEP);
}
static void
ddt_free(const ddt_t *ddt, ddt_entry_t *dde)
{
if (dde->dde_io != NULL) {
for (int p = 0; p < DDT_NPHYS(ddt); p++)
ASSERT3P(dde->dde_io->dde_lead_zio[p], ==, NULL);
if (dde->dde_io->dde_repair_abd != NULL)
abd_free(dde->dde_io->dde_repair_abd);
kmem_free(dde->dde_io, sizeof (ddt_entry_io_t));
}
cv_destroy(&dde->dde_cv);
kmem_cache_free(ddt->ddt_flags & DDT_FLAG_FLAT ?
ddt_entry_flat_cache : ddt_entry_trad_cache, dde);
}
void
ddt_remove(ddt_t *ddt, ddt_entry_t *dde)
{
ASSERT(MUTEX_HELD(&ddt->ddt_lock));
/* Entry is still in the log, so charge the entry back to it */
if (dde->dde_flags & DDE_FLAG_LOGGED) {
ddt_lightweight_entry_t ddlwe;
DDT_ENTRY_TO_LIGHTWEIGHT(ddt, dde, &ddlwe);
ddt_histogram_add_entry(ddt, &ddt->ddt_log_histogram, &ddlwe);
}
avl_remove(&ddt->ddt_tree, dde);
ddt_free(ddt, dde);
}
static boolean_t
ddt_special_over_quota(spa_t *spa, metaslab_class_t *mc)
{
if (mc != NULL && metaslab_class_get_space(mc) > 0) {
/* Over quota if allocating outside of this special class */
if (spa_syncing_txg(spa) <= spa->spa_dedup_class_full_txg +
dedup_class_wait_txgs) {
/* Waiting for some deferred frees to be processed */
return (B_TRUE);
}
/*
* We're considered over quota when we hit 85% full, or for
* larger drives, when there is less than 8GB free.
*/
uint64_t allocated = metaslab_class_get_alloc(mc);
uint64_t capacity = metaslab_class_get_space(mc);
uint64_t limit = MAX(capacity * 85 / 100,
(capacity > (1LL<<33)) ? capacity - (1LL<<33) : 0);
return (allocated >= limit);
}
return (B_FALSE);
}
/*
* Check if the DDT is over its quota. This can be due to a few conditions:
* 1. 'dedup_table_quota' property is not 0 (none) and the dedup dsize
* exceeds this limit
*
* 2. 'dedup_table_quota' property is set to automatic and
* a. the dedup or special allocation class could not satisfy a DDT
* allocation in a recent transaction
* b. the dedup or special allocation class has exceeded its 85% limit
*/
static boolean_t
ddt_over_quota(spa_t *spa)
{
if (spa->spa_dedup_table_quota == 0)
return (B_FALSE);
if (spa->spa_dedup_table_quota != UINT64_MAX)
return (ddt_get_ddt_dsize(spa) > spa->spa_dedup_table_quota);
/*
* For automatic quota, table size is limited by dedup or special class
*/
if (ddt_special_over_quota(spa, spa_dedup_class(spa)))
return (B_TRUE);
else if (spa_special_has_ddt(spa) &&
ddt_special_over_quota(spa, spa_special_class(spa)))
return (B_TRUE);
return (B_FALSE);
}
void
ddt_prefetch_all(spa_t *spa)
{
/*
* Load all DDT entries for each type/class combination. This is
* indended to perform a prefetch on all such blocks. For the same
* reason that ddt_prefetch isn't locked, this is also not locked.
*/
for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
ddt_t *ddt = spa->spa_ddt[c];
if (!ddt)
continue;
for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
for (ddt_class_t class = 0; class < DDT_CLASSES;
class++) {
ddt_object_prefetch_all(ddt, type, class);
}
}
}
}
static int ddt_configure(ddt_t *ddt, boolean_t new);
/*
* If the BP passed to ddt_lookup has valid DVAs, then we need to compare them
* to the ones in the entry. If they're different, then the passed-in BP is
* from a previous generation of this entry (ie was previously pruned) and we
* have to act like the entry doesn't exist at all.
*
* This should only happen during a lookup to free the block (zio_ddt_free()).
*
* XXX this is similar in spirit to ddt_phys_select(), maybe can combine
* -- robn, 2024-02-09
*/
static boolean_t
ddt_entry_lookup_is_valid(ddt_t *ddt, const blkptr_t *bp, ddt_entry_t *dde)
{
/* If the BP has no DVAs, then this entry is good */
uint_t ndvas = BP_GET_NDVAS(bp);
if (ndvas == 0)
return (B_TRUE);
/*
* Only checking the phys for the copies. For flat, there's only one;
* for trad it'll be the one that has the matching set of DVAs.
*/
const dva_t *dvas = (ddt->ddt_flags & DDT_FLAG_FLAT) ?
dde->dde_phys->ddp_flat.ddp_dva :
dde->dde_phys->ddp_trad[ndvas].ddp_dva;
/*
* Compare entry DVAs with the BP. They should all be there, but
* there's not really anything we can do if its only partial anyway,
* that's an error somewhere else, maybe long ago.
*/
uint_t d;
for (d = 0; d < ndvas; d++)
if (!DVA_EQUAL(&dvas[d], &bp->blk_dva[d]))
return (B_FALSE);
ASSERT3U(d, ==, ndvas);
return (B_TRUE);
}
ddt_entry_t *
ddt_lookup(ddt_t *ddt, const blkptr_t *bp)
{
spa_t *spa = ddt->ddt_spa;
ddt_key_t search;
ddt_entry_t *dde;
ddt_type_t type;
ddt_class_t class;
avl_index_t where;
int error;
ASSERT(MUTEX_HELD(&ddt->ddt_lock));
if (ddt->ddt_version == DDT_VERSION_UNCONFIGURED) {
/*
* This is the first use of this DDT since the pool was
* created; finish getting it ready for use.
*/
VERIFY0(ddt_configure(ddt, B_TRUE));
ASSERT3U(ddt->ddt_version, !=, DDT_VERSION_UNCONFIGURED);
}
DDT_KSTAT_BUMP(ddt, dds_lookup);
ddt_key_fill(&search, bp);
/* Find an existing live entry */
dde = avl_find(&ddt->ddt_tree, &search, &where);
if (dde != NULL) {
/* If we went over quota, act like we didn't find it */
if (dde->dde_flags & DDE_FLAG_OVERQUOTA)
return (NULL);
/* If it's already loaded, we can just return it. */
DDT_KSTAT_BUMP(ddt, dds_lookup_live_hit);
if (dde->dde_flags & DDE_FLAG_LOADED) {
if (ddt_entry_lookup_is_valid(ddt, bp, dde))
return (dde);
return (NULL);
}
/* Someone else is loading it, wait for it. */
dde->dde_waiters++;
DDT_KSTAT_BUMP(ddt, dds_lookup_live_wait);
while (!(dde->dde_flags & DDE_FLAG_LOADED))
cv_wait(&dde->dde_cv, &ddt->ddt_lock);
dde->dde_waiters--;
/* Loaded but over quota, forget we were ever here */
if (dde->dde_flags & DDE_FLAG_OVERQUOTA) {
if (dde->dde_waiters == 0) {
avl_remove(&ddt->ddt_tree, dde);
ddt_free(ddt, dde);
}
return (NULL);
}
DDT_KSTAT_BUMP(ddt, dds_lookup_existing);
/* Make sure the loaded entry matches the BP */
if (ddt_entry_lookup_is_valid(ddt, bp, dde))
return (dde);
return (NULL);
} else
DDT_KSTAT_BUMP(ddt, dds_lookup_live_miss);
/* Time to make a new entry. */
dde = ddt_alloc(ddt, &search);
/* Record the time this class was created (used by ddt prune) */
if (ddt->ddt_flags & DDT_FLAG_FLAT)
dde->dde_phys->ddp_flat.ddp_class_start = ddt_class_start();
avl_insert(&ddt->ddt_tree, dde, where);
/* If its in the log tree, we can "load" it from there */
if (ddt->ddt_flags & DDT_FLAG_LOG) {
ddt_lightweight_entry_t ddlwe;
if (ddt_log_find_key(ddt, &search, &ddlwe)) {
/*
* See if we have the key first, and if so, set up
* the entry.
*/
dde->dde_type = ddlwe.ddlwe_type;
dde->dde_class = ddlwe.ddlwe_class;
memcpy(dde->dde_phys, &ddlwe.ddlwe_phys,
DDT_PHYS_SIZE(ddt));
/* Whatever we found isn't valid for this BP, eject */
if (!ddt_entry_lookup_is_valid(ddt, bp, dde)) {
avl_remove(&ddt->ddt_tree, dde);
ddt_free(ddt, dde);
return (NULL);
}
/* Remove it and count it */
if (ddt_log_remove_key(ddt,
ddt->ddt_log_active, &search)) {
DDT_KSTAT_BUMP(ddt, dds_lookup_log_active_hit);
} else {
VERIFY(ddt_log_remove_key(ddt,
ddt->ddt_log_flushing, &search));
DDT_KSTAT_BUMP(ddt,
dds_lookup_log_flushing_hit);
}
dde->dde_flags = DDE_FLAG_LOADED | DDE_FLAG_LOGGED;
DDT_KSTAT_BUMP(ddt, dds_lookup_log_hit);
DDT_KSTAT_BUMP(ddt, dds_lookup_existing);
return (dde);
}
DDT_KSTAT_BUMP(ddt, dds_lookup_log_miss);
}
/*
* ddt_tree is now stable, so unlock and let everyone else keep moving.
* Anyone landing on this entry will find it without DDE_FLAG_LOADED,
* and go to sleep waiting for it above.
*/
ddt_exit(ddt);
/* Search all store objects for the entry. */
error = ENOENT;
for (type = 0; type < DDT_TYPES; type++) {
for (class = 0; class < DDT_CLASSES; class++) {
error = ddt_object_lookup(ddt, type, class, dde);
if (error != ENOENT) {
ASSERT0(error);
break;
}
}
if (error != ENOENT)
break;
}
ddt_enter(ddt);
ASSERT(!(dde->dde_flags & DDE_FLAG_LOADED));
dde->dde_type = type; /* will be DDT_TYPES if no entry found */
dde->dde_class = class; /* will be DDT_CLASSES if no entry found */
boolean_t valid = B_TRUE;
if (dde->dde_type == DDT_TYPES &&
dde->dde_class == DDT_CLASSES &&
ddt_over_quota(spa)) {
/* Over quota. If no one is waiting, clean up right now. */
if (dde->dde_waiters == 0) {
avl_remove(&ddt->ddt_tree, dde);
ddt_free(ddt, dde);
return (NULL);
}
/* Flag cleanup required */
dde->dde_flags |= DDE_FLAG_OVERQUOTA;
} else if (error == 0) {
/*
* If what we loaded is no good for this BP and there's no one
* waiting for it, we can just remove it and get out. If its no
* good but there are waiters, we have to leave it, because we
* don't know what they want. If its not needed we'll end up
* taking an entry log/sync, but it can only happen if more
* than one previous version of this block is being deleted at
* the same time. This is extremely unlikely to happen and not
* worth the effort to deal with without taking an entry
* update.
*/
valid = ddt_entry_lookup_is_valid(ddt, bp, dde);
if (!valid && dde->dde_waiters == 0) {
avl_remove(&ddt->ddt_tree, dde);
ddt_free(ddt, dde);
return (NULL);
}
DDT_KSTAT_BUMP(ddt, dds_lookup_stored_hit);
DDT_KSTAT_BUMP(ddt, dds_lookup_existing);
/*
* The histograms only track inactive (stored or logged) blocks.
* We've just put an entry onto the live list, so we need to
* remove its counts. When its synced back, it'll be re-added
* to the right one.
*
* We only do this when we successfully found it in the store.
* error == ENOENT means this is a new entry, and so its already
* not counted.
*/
ddt_histogram_t *ddh =
&ddt->ddt_histogram[dde->dde_type][dde->dde_class];
ddt_lightweight_entry_t ddlwe;
DDT_ENTRY_TO_LIGHTWEIGHT(ddt, dde, &ddlwe);
ddt_histogram_sub_entry(ddt, ddh, &ddlwe);
} else {
DDT_KSTAT_BUMP(ddt, dds_lookup_stored_miss);
DDT_KSTAT_BUMP(ddt, dds_lookup_new);
}
/* Entry loaded, everyone can proceed now */
dde->dde_flags |= DDE_FLAG_LOADED;
cv_broadcast(&dde->dde_cv);
if ((dde->dde_flags & DDE_FLAG_OVERQUOTA) || !valid)
return (NULL);
return (dde);
}
void
ddt_prefetch(spa_t *spa, const blkptr_t *bp)
{
ddt_t *ddt;
ddt_key_t ddk;
if (!zfs_dedup_prefetch || bp == NULL || !BP_GET_DEDUP(bp))
return;
/*
* We only remove the DDT once all tables are empty and only
* prefetch dedup blocks when there are entries in the DDT.
* Thus no locking is required as the DDT can't disappear on us.
*/
ddt = ddt_select(spa, bp);
ddt_key_fill(&ddk, bp);
for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
for (ddt_class_t class = 0; class < DDT_CLASSES; class++) {
ddt_object_prefetch(ddt, type, class, &ddk);
}
}
}
/*
* ddt_key_t comparison. Any struct wanting to make use of this function must
* have the key as the first element. Casts it to N uint64_ts, and checks until
* we find there's a difference. This is intended to match how ddt_zap.c drives
* the ZAPs (first uint64_t as the key prehash), which will minimise the number
* of ZAP blocks touched when flushing logged entries from an AVL walk. This is
* not an invariant for this function though, should you wish to change it.
*/
int
ddt_key_compare(const void *x1, const void *x2)
{
const uint64_t *k1 = (const uint64_t *)x1;
const uint64_t *k2 = (const uint64_t *)x2;
int cmp;
for (int i = 0; i < (sizeof (ddt_key_t) / sizeof (uint64_t)); i++)
if (likely((cmp = TREE_CMP(k1[i], k2[i])) != 0))
return (cmp);
return (0);
}
/* Create the containing dir for this DDT and bump the feature count */
static void
ddt_create_dir(ddt_t *ddt, dmu_tx_t *tx)
{
ASSERT3U(ddt->ddt_dir_object, ==, 0);
ASSERT3U(ddt->ddt_version, ==, DDT_VERSION_FDT);
char name[DDT_NAMELEN];
snprintf(name, DDT_NAMELEN, DMU_POOL_DDT_DIR,
zio_checksum_table[ddt->ddt_checksum].ci_name);
ddt->ddt_dir_object = zap_create_link(ddt->ddt_os,
DMU_OTN_ZAP_METADATA, DMU_POOL_DIRECTORY_OBJECT, name, tx);
VERIFY0(zap_add(ddt->ddt_os, ddt->ddt_dir_object, DDT_DIR_VERSION,
sizeof (uint64_t), 1, &ddt->ddt_version, tx));
VERIFY0(zap_add(ddt->ddt_os, ddt->ddt_dir_object, DDT_DIR_FLAGS,
sizeof (uint64_t), 1, &ddt->ddt_flags, tx));
spa_feature_incr(ddt->ddt_spa, SPA_FEATURE_FAST_DEDUP, tx);
}
/* Destroy the containing dir and deactivate the feature */
static void
ddt_destroy_dir(ddt_t *ddt, dmu_tx_t *tx)
{
ASSERT3U(ddt->ddt_dir_object, !=, 0);
ASSERT3U(ddt->ddt_dir_object, !=, DMU_POOL_DIRECTORY_OBJECT);
ASSERT3U(ddt->ddt_version, ==, DDT_VERSION_FDT);
char name[DDT_NAMELEN];
snprintf(name, DDT_NAMELEN, DMU_POOL_DDT_DIR,
zio_checksum_table[ddt->ddt_checksum].ci_name);
for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
for (ddt_class_t class = 0; class < DDT_CLASSES; class++) {
ASSERT(!ddt_object_exists(ddt, type, class));
}
}
ddt_log_destroy(ddt, tx);
uint64_t count;
ASSERT0(zap_count(ddt->ddt_os, ddt->ddt_dir_object, &count));
ASSERT0(zap_contains(ddt->ddt_os, ddt->ddt_dir_object,
DDT_DIR_VERSION));
ASSERT0(zap_contains(ddt->ddt_os, ddt->ddt_dir_object, DDT_DIR_FLAGS));
ASSERT3U(count, ==, 2);
VERIFY0(zap_remove(ddt->ddt_os, DMU_POOL_DIRECTORY_OBJECT, name, tx));
VERIFY0(zap_destroy(ddt->ddt_os, ddt->ddt_dir_object, tx));
ddt->ddt_dir_object = 0;
spa_feature_decr(ddt->ddt_spa, SPA_FEATURE_FAST_DEDUP, tx);
}
/*
* Determine, flags and on-disk layout from what's already stored. If there's
* nothing stored, then if new is false, returns ENOENT, and if true, selects
* based on pool config.
*/
static int
ddt_configure(ddt_t *ddt, boolean_t new)
{
spa_t *spa = ddt->ddt_spa;
char name[DDT_NAMELEN];
int error;
ASSERT3U(spa_load_state(spa), !=, SPA_LOAD_CREATE);
boolean_t fdt_enabled =
spa_feature_is_enabled(spa, SPA_FEATURE_FAST_DEDUP);
boolean_t fdt_active =
spa_feature_is_active(spa, SPA_FEATURE_FAST_DEDUP);
/*
* First, look for the global DDT stats object. If its not there, then
* there's never been a DDT written before ever, and we know we're
* starting from scratch.
*/
error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_DDT_STATS, sizeof (uint64_t), 1,
&spa->spa_ddt_stat_object);
if (error != 0) {
if (error != ENOENT)
return (error);
goto not_found;
}
if (fdt_active) {
/*
* Now look for a DDT directory. If it exists, then it has
* everything we need.
*/
snprintf(name, DDT_NAMELEN, DMU_POOL_DDT_DIR,
zio_checksum_table[ddt->ddt_checksum].ci_name);
error = zap_lookup(spa->spa_meta_objset,
DMU_POOL_DIRECTORY_OBJECT, name, sizeof (uint64_t), 1,
&ddt->ddt_dir_object);
if (error == 0) {
ASSERT3U(spa->spa_meta_objset, ==, ddt->ddt_os);
error = zap_lookup(ddt->ddt_os, ddt->ddt_dir_object,
DDT_DIR_VERSION, sizeof (uint64_t), 1,
&ddt->ddt_version);
if (error != 0)
return (error);
error = zap_lookup(ddt->ddt_os, ddt->ddt_dir_object,
DDT_DIR_FLAGS, sizeof (uint64_t), 1,
&ddt->ddt_flags);
if (error != 0)
return (error);
if (ddt->ddt_version != DDT_VERSION_FDT) {
zfs_dbgmsg("ddt_configure: spa=%s ddt_dir=%s "
"unknown version %llu", spa_name(spa),
name, (u_longlong_t)ddt->ddt_version);
return (SET_ERROR(EINVAL));
}
if ((ddt->ddt_flags & ~DDT_FLAG_MASK) != 0) {
zfs_dbgmsg("ddt_configure: spa=%s ddt_dir=%s "
"version=%llu unknown flags %llx",
spa_name(spa), name,
(u_longlong_t)ddt->ddt_flags,
(u_longlong_t)ddt->ddt_version);
return (SET_ERROR(EINVAL));
}
return (0);
}
if (error != ENOENT)
return (error);
}
/* Any object in the root indicates a traditional setup. */
for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
for (ddt_class_t class = 0; class < DDT_CLASSES; class++) {
ddt_object_name(ddt, type, class, name);
uint64_t obj;
error = zap_lookup(spa->spa_meta_objset,
DMU_POOL_DIRECTORY_OBJECT, name, sizeof (uint64_t),
1, &obj);
if (error == ENOENT)
continue;
if (error != 0)
return (error);
ddt->ddt_version = DDT_VERSION_LEGACY;
ddt->ddt_flags = ddt_version_flags[ddt->ddt_version];
ddt->ddt_dir_object = DMU_POOL_DIRECTORY_OBJECT;
return (0);
}
}
not_found:
if (!new)
return (SET_ERROR(ENOENT));
/* Nothing on disk, so set up for the best version we can */
if (fdt_enabled) {
ddt->ddt_version = DDT_VERSION_FDT;
ddt->ddt_flags = ddt_version_flags[ddt->ddt_version];
ddt->ddt_dir_object = 0; /* create on first use */
} else {
ddt->ddt_version = DDT_VERSION_LEGACY;
ddt->ddt_flags = ddt_version_flags[ddt->ddt_version];
ddt->ddt_dir_object = DMU_POOL_DIRECTORY_OBJECT;
}
return (0);
}
static void
ddt_table_alloc_kstats(ddt_t *ddt)
{
char *mod = kmem_asprintf("zfs/%s", spa_name(ddt->ddt_spa));
char *name = kmem_asprintf("ddt_stats_%s",
zio_checksum_table[ddt->ddt_checksum].ci_name);
ddt->ddt_ksp = kstat_create(mod, 0, name, "misc", KSTAT_TYPE_NAMED,
sizeof (ddt_kstats_t) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL);
if (ddt->ddt_ksp != NULL) {
ddt_kstats_t *dds = kmem_alloc(sizeof (ddt_kstats_t), KM_SLEEP);
memcpy(dds, &ddt_kstats_template, sizeof (ddt_kstats_t));
ddt->ddt_ksp->ks_data = dds;
kstat_install(ddt->ddt_ksp);
}
kmem_strfree(name);
kmem_strfree(mod);
}
static ddt_t *
ddt_table_alloc(spa_t *spa, enum zio_checksum c)
{
ddt_t *ddt;
ddt = kmem_cache_alloc(ddt_cache, KM_SLEEP);
memset(ddt, 0, sizeof (ddt_t));
mutex_init(&ddt->ddt_lock, NULL, MUTEX_DEFAULT, NULL);
avl_create(&ddt->ddt_tree, ddt_key_compare,
sizeof (ddt_entry_t), offsetof(ddt_entry_t, dde_node));
avl_create(&ddt->ddt_repair_tree, ddt_key_compare,
sizeof (ddt_entry_t), offsetof(ddt_entry_t, dde_node));
ddt->ddt_checksum = c;
ddt->ddt_spa = spa;
ddt->ddt_os = spa->spa_meta_objset;
ddt->ddt_version = DDT_VERSION_UNCONFIGURED;
ddt_log_alloc(ddt);
ddt_table_alloc_kstats(ddt);
return (ddt);
}
static void
ddt_table_free(ddt_t *ddt)
{
if (ddt->ddt_ksp != NULL) {
kmem_free(ddt->ddt_ksp->ks_data, sizeof (ddt_kstats_t));
ddt->ddt_ksp->ks_data = NULL;
kstat_delete(ddt->ddt_ksp);
}
ddt_log_free(ddt);
ASSERT0(avl_numnodes(&ddt->ddt_tree));
ASSERT0(avl_numnodes(&ddt->ddt_repair_tree));
avl_destroy(&ddt->ddt_tree);
avl_destroy(&ddt->ddt_repair_tree);
mutex_destroy(&ddt->ddt_lock);
kmem_cache_free(ddt_cache, ddt);
}
void
ddt_create(spa_t *spa)
{
spa->spa_dedup_checksum = ZIO_DEDUPCHECKSUM;
for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
if (DDT_CHECKSUM_VALID(c))
spa->spa_ddt[c] = ddt_table_alloc(spa, c);
}
}
int
ddt_load(spa_t *spa)
{
int error;
ddt_create(spa);
error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_DDT_STATS, sizeof (uint64_t), 1,
&spa->spa_ddt_stat_object);
if (error)
return (error == ENOENT ? 0 : error);
for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
if (!DDT_CHECKSUM_VALID(c))
continue;
ddt_t *ddt = spa->spa_ddt[c];
error = ddt_configure(ddt, B_FALSE);
if (error == ENOENT)
continue;
if (error != 0)
return (error);
for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
for (ddt_class_t class = 0; class < DDT_CLASSES;
class++) {
error = ddt_object_load(ddt, type, class);
if (error != 0 && error != ENOENT)
return (error);
}
}
error = ddt_log_load(ddt);
if (error != 0 && error != ENOENT)
return (error);
DDT_KSTAT_SET(ddt, dds_log_active_entries,
avl_numnodes(&ddt->ddt_log_active->ddl_tree));
DDT_KSTAT_SET(ddt, dds_log_flushing_entries,
avl_numnodes(&ddt->ddt_log_flushing->ddl_tree));
/*
* Seed the cached histograms.
*/
memcpy(&ddt->ddt_histogram_cache, ddt->ddt_histogram,
sizeof (ddt->ddt_histogram));
}
spa->spa_dedup_dspace = ~0ULL;
spa->spa_dedup_dsize = ~0ULL;
return (0);
}
void
ddt_unload(spa_t *spa)
{
for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
if (spa->spa_ddt[c]) {
ddt_table_free(spa->spa_ddt[c]);
spa->spa_ddt[c] = NULL;
}
}
}
boolean_t
ddt_class_contains(spa_t *spa, ddt_class_t max_class, const blkptr_t *bp)
{
ddt_t *ddt;
ddt_key_t ddk;
if (!BP_GET_DEDUP(bp))
return (B_FALSE);
if (max_class == DDT_CLASS_UNIQUE)
return (B_TRUE);
ddt = spa->spa_ddt[BP_GET_CHECKSUM(bp)];
ddt_key_fill(&ddk, bp);
for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
for (ddt_class_t class = 0; class <= max_class; class++) {
if (ddt_object_contains(ddt, type, class, &ddk) == 0)
return (B_TRUE);
}
}
return (B_FALSE);
}
ddt_entry_t *
ddt_repair_start(ddt_t *ddt, const blkptr_t *bp)
{
ddt_key_t ddk;
ddt_entry_t *dde;
ddt_key_fill(&ddk, bp);
dde = ddt_alloc(ddt, &ddk);
ddt_alloc_entry_io(dde);
for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
for (ddt_class_t class = 0; class < DDT_CLASSES; class++) {
/*
* We can only do repair if there are multiple copies
* of the block. For anything in the UNIQUE class,
* there's definitely only one copy, so don't even try.
*/
if (class != DDT_CLASS_UNIQUE &&
ddt_object_lookup(ddt, type, class, dde) == 0)
return (dde);
}
}
memset(dde->dde_phys, 0, DDT_PHYS_SIZE(ddt));
return (dde);
}
void
ddt_repair_done(ddt_t *ddt, ddt_entry_t *dde)
{
avl_index_t where;
ddt_enter(ddt);
if (dde->dde_io->dde_repair_abd != NULL &&
spa_writeable(ddt->ddt_spa) &&
avl_find(&ddt->ddt_repair_tree, dde, &where) == NULL)
avl_insert(&ddt->ddt_repair_tree, dde, where);
else
ddt_free(ddt, dde);
ddt_exit(ddt);
}
static void
ddt_repair_entry_done(zio_t *zio)
{
ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
ddt_entry_t *rdde = zio->io_private;
ddt_free(ddt, rdde);
}
static void
ddt_repair_entry(ddt_t *ddt, ddt_entry_t *dde, ddt_entry_t *rdde, zio_t *rio)
{
ddt_key_t *ddk = &dde->dde_key;
ddt_key_t *rddk = &rdde->dde_key;
zio_t *zio;
blkptr_t blk;
zio = zio_null(rio, rio->io_spa, NULL,
ddt_repair_entry_done, rdde, rio->io_flags);
for (int p = 0; p < DDT_NPHYS(ddt); p++) {
ddt_univ_phys_t *ddp = dde->dde_phys;
ddt_univ_phys_t *rddp = rdde->dde_phys;
ddt_phys_variant_t v = DDT_PHYS_VARIANT(ddt, p);
uint64_t phys_birth = ddt_phys_birth(ddp, v);
const dva_t *dvas, *rdvas;
if (ddt->ddt_flags & DDT_FLAG_FLAT) {
dvas = ddp->ddp_flat.ddp_dva;
rdvas = rddp->ddp_flat.ddp_dva;
} else {
dvas = ddp->ddp_trad[p].ddp_dva;
rdvas = rddp->ddp_trad[p].ddp_dva;
}
if (phys_birth == 0 ||
phys_birth != ddt_phys_birth(rddp, v) ||
memcmp(dvas, rdvas, sizeof (dva_t) * SPA_DVAS_PER_BP))
continue;
ddt_bp_create(ddt->ddt_checksum, ddk, ddp, v, &blk);
zio_nowait(zio_rewrite(zio, zio->io_spa, 0, &blk,
rdde->dde_io->dde_repair_abd, DDK_GET_PSIZE(rddk),
NULL, NULL, ZIO_PRIORITY_SYNC_WRITE,
ZIO_DDT_CHILD_FLAGS(zio), NULL));
}
zio_nowait(zio);
}
static void
ddt_repair_table(ddt_t *ddt, zio_t *rio)
{
spa_t *spa = ddt->ddt_spa;
ddt_entry_t *dde, *rdde_next, *rdde;
avl_tree_t *t = &ddt->ddt_repair_tree;
blkptr_t blk;
if (spa_sync_pass(spa) > 1)
return;
ddt_enter(ddt);
for (rdde = avl_first(t); rdde != NULL; rdde = rdde_next) {
rdde_next = AVL_NEXT(t, rdde);
avl_remove(&ddt->ddt_repair_tree, rdde);
ddt_exit(ddt);
ddt_bp_create(ddt->ddt_checksum, &rdde->dde_key, NULL,
DDT_PHYS_NONE, &blk);
dde = ddt_repair_start(ddt, &blk);
ddt_repair_entry(ddt, dde, rdde, rio);
ddt_repair_done(ddt, dde);
ddt_enter(ddt);
}
ddt_exit(ddt);
}
static void
ddt_sync_update_stats(ddt_t *ddt, dmu_tx_t *tx)
{
/*
* Count all the entries stored for each type/class, and updates the
* stats within (ddt_object_sync()). If there's no entries for the
* type/class, the whole object is removed. If all objects for the DDT
* are removed, its containing dir is removed, effectively resetting
* the entire DDT to an empty slate.
*/
uint64_t count = 0;
for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
uint64_t add, tcount = 0;
for (ddt_class_t class = 0; class < DDT_CLASSES; class++) {
if (ddt_object_exists(ddt, type, class)) {
ddt_object_sync(ddt, type, class, tx);
VERIFY0(ddt_object_count(ddt, type, class,
&add));
tcount += add;
}
}
for (ddt_class_t class = 0; class < DDT_CLASSES; class++) {
if (tcount == 0 && ddt_object_exists(ddt, type, class))
ddt_object_destroy(ddt, type, class, tx);
}
count += tcount;
}
if (ddt->ddt_flags & DDT_FLAG_LOG) {
/* Include logged entries in the total count */
count += avl_numnodes(&ddt->ddt_log_active->ddl_tree);
count += avl_numnodes(&ddt->ddt_log_flushing->ddl_tree);
}
if (count == 0) {
/*
* No entries left on the DDT, so reset the version for next
* time. This allows us to handle the feature being changed
* since the DDT was originally created. New entries should get
* whatever the feature currently demands.
*/
if (ddt->ddt_version == DDT_VERSION_FDT)
ddt_destroy_dir(ddt, tx);
ddt->ddt_version = DDT_VERSION_UNCONFIGURED;
ddt->ddt_flags = 0;
}
memcpy(&ddt->ddt_histogram_cache, ddt->ddt_histogram,
sizeof (ddt->ddt_histogram));
ddt->ddt_spa->spa_dedup_dspace = ~0ULL;
ddt->ddt_spa->spa_dedup_dsize = ~0ULL;
}
static void
ddt_sync_scan_entry(ddt_t *ddt, ddt_lightweight_entry_t *ddlwe, dmu_tx_t *tx)
{
dsl_pool_t *dp = ddt->ddt_spa->spa_dsl_pool;
/*
* Compute the target class, so we can decide whether or not to inform
* the scrub traversal (below). Note that we don't store this in the
* entry, as it might change multiple times before finally being
* committed (if we're logging). Instead, we recompute it in
* ddt_sync_entry().
*/
uint64_t refcnt = ddt_phys_total_refcnt(ddt, &ddlwe->ddlwe_phys);
ddt_class_t nclass =
(refcnt > 1) ? DDT_CLASS_DUPLICATE : DDT_CLASS_UNIQUE;
/*
* If the class changes, the order that we scan this bp changes. If it
* decreases, we could miss it, so scan it right now. (This covers both
* class changing while we are doing ddt_walk(), and when we are
* traversing.)
*
* We also do this when the refcnt goes to zero, because that change is
* only in the log so far; the blocks on disk won't be freed until
* the log is flushed, and the refcnt might increase before that. If it
* does, then we could miss it in the same way.
*/
if (refcnt == 0 || nclass < ddlwe->ddlwe_class)
dsl_scan_ddt_entry(dp->dp_scan, ddt->ddt_checksum, ddt,
ddlwe, tx);
}
static void
ddt_sync_flush_entry(ddt_t *ddt, ddt_lightweight_entry_t *ddlwe,
ddt_type_t otype, ddt_class_t oclass, dmu_tx_t *tx)
{
ddt_key_t *ddk = &ddlwe->ddlwe_key;
ddt_type_t ntype = DDT_TYPE_DEFAULT;
uint64_t refcnt = 0;
/*
* Compute the total refcnt. Along the way, issue frees for any DVAs
* we no longer want.
*/
for (int p = 0; p < DDT_NPHYS(ddt); p++) {
ddt_univ_phys_t *ddp = &ddlwe->ddlwe_phys;
ddt_phys_variant_t v = DDT_PHYS_VARIANT(ddt, p);
uint64_t phys_refcnt = ddt_phys_refcnt(ddp, v);
if (ddt_phys_birth(ddp, v) == 0) {
ASSERT0(phys_refcnt);
continue;
}
if (DDT_PHYS_IS_DITTO(ddt, p)) {
/*
* We don't want to keep any obsolete slots (eg ditto),
* regardless of their refcount, but we don't want to
* leak them either. So, free them.
*/
ddt_phys_free(ddt, ddk, ddp, v, tx->tx_txg);
continue;
}
if (phys_refcnt == 0)
/* No remaining references, free it! */
ddt_phys_free(ddt, ddk, ddp, v, tx->tx_txg);
refcnt += phys_refcnt;
}
/* Select the best class for the entry. */
ddt_class_t nclass =
(refcnt > 1) ? DDT_CLASS_DUPLICATE : DDT_CLASS_UNIQUE;
/*
* If an existing entry changed type or class, or its refcount reached
* zero, delete it from the DDT object
*/
if (otype != DDT_TYPES &&
(otype != ntype || oclass != nclass || refcnt == 0)) {
VERIFY0(ddt_object_remove(ddt, otype, oclass, ddk, tx));
ASSERT(ddt_object_contains(ddt, otype, oclass, ddk) == ENOENT);
}
/*
* Add or update the entry
*/
if (refcnt != 0) {
ddt_histogram_t *ddh =
&ddt->ddt_histogram[ntype][nclass];
ddt_histogram_add_entry(ddt, ddh, ddlwe);
if (!ddt_object_exists(ddt, ntype, nclass))
ddt_object_create(ddt, ntype, nclass, tx);
VERIFY0(ddt_object_update(ddt, ntype, nclass, ddlwe, tx));
}
}
/* Calculate an exponential weighted moving average, lower limited to zero */
static inline int32_t
_ewma(int32_t val, int32_t prev, uint32_t weight)
{
ASSERT3U(val, >=, 0);
ASSERT3U(prev, >=, 0);
const int32_t new =
MAX(0, prev + (val-prev) / (int32_t)MAX(weight, 1));
ASSERT3U(new, >=, 0);
return (new);
}
/* Returns true if done for this txg */
static boolean_t
ddt_sync_flush_log_incremental(ddt_t *ddt, dmu_tx_t *tx)
{
if (ddt->ddt_flush_pass == 0) {
if (spa_sync_pass(ddt->ddt_spa) == 1) {
/* First run this txg, get set up */
ddt->ddt_flush_start = gethrtime();
ddt->ddt_flush_count = 0;
/*
* How many entries we need to flush. We want to at
* least match the ingest rate.
*/
ddt->ddt_flush_min = MAX(
ddt->ddt_log_ingest_rate,
zfs_dedup_log_flush_entries_min);
/*
* If we've been asked to flush everything in a hurry,
* try to dump as much as possible on this txg. In
* this case we're only limited by time, not amount.
*/
if (ddt->ddt_flush_force_txg > 0)
ddt->ddt_flush_min =
MAX(ddt->ddt_flush_min, avl_numnodes(
&ddt->ddt_log_flushing->ddl_tree));
} else {
/* We already decided we're done for this txg */
return (B_FALSE);
}
} else if (ddt->ddt_flush_pass == spa_sync_pass(ddt->ddt_spa)) {
/*
* We already did some flushing on this pass, skip it. This
* happens when dsl_process_async_destroys() runs during a scan
* (on pass 1) and does an additional ddt_sync() to update
* freed blocks.
*/
return (B_FALSE);
}
if (spa_sync_pass(ddt->ddt_spa) >
MAX(zfs_dedup_log_flush_passes_max, 1)) {
/* Too many passes this txg, defer until next. */
ddt->ddt_flush_pass = 0;
return (B_TRUE);
}
if (avl_is_empty(&ddt->ddt_log_flushing->ddl_tree)) {
/* Nothing to flush, done for this txg. */
ddt->ddt_flush_pass = 0;
return (B_TRUE);
}
uint64_t target_time = txg_sync_waiting(ddt->ddt_spa->spa_dsl_pool) ?
MIN(MSEC2NSEC(zfs_dedup_log_flush_min_time_ms),
SEC2NSEC(zfs_txg_timeout)) : SEC2NSEC(zfs_txg_timeout);
uint64_t elapsed_time = gethrtime() - ddt->ddt_flush_start;
if (elapsed_time >= target_time) {
/* Too long since we started, done for this txg. */
ddt->ddt_flush_pass = 0;
return (B_TRUE);
}
ddt->ddt_flush_pass++;
ASSERT3U(spa_sync_pass(ddt->ddt_spa), ==, ddt->ddt_flush_pass);
/*
* Estimate how much time we'll need to flush the remaining entries
* based on how long it normally takes.
*/
uint32_t want_time;
if (ddt->ddt_flush_pass == 1) {
/* First pass, use the average time/entries */
if (ddt->ddt_log_flush_rate == 0)
/* Zero rate, just assume the whole time */
want_time = target_time;
else
want_time = ddt->ddt_flush_min *
ddt->ddt_log_flush_time_rate /
ddt->ddt_log_flush_rate;
} else {
/* Later pass, calculate from this txg so far */
want_time = ddt->ddt_flush_min *
elapsed_time / ddt->ddt_flush_count;
}
/* Figure out how much time we have left */
uint32_t remain_time = target_time - elapsed_time;
/* Smear the remaining entries over the remaining passes. */
uint32_t nentries = ddt->ddt_flush_min /
(MAX(1, zfs_dedup_log_flush_passes_max) + 1 - ddt->ddt_flush_pass);
if (want_time > remain_time) {
/*
* We're behind; try to catch up a bit by doubling the amount
* this pass. If we're behind that means we're in a later
* pass and likely have most of the remaining time to
* ourselves. If we're in the last couple of passes, then
* doubling might just take us over the timeout, but probably
* not be much, and it stops us falling behind. If we're
* in the middle passes, there'll be more to do, but it
* might just help us catch up a bit and we'll recalculate on
* the next pass anyway.
*/
nentries = MIN(ddt->ddt_flush_min, nentries*2);
}
ddt_lightweight_entry_t ddlwe;
uint32_t count = 0;
while (ddt_log_take_first(ddt, ddt->ddt_log_flushing, &ddlwe)) {
ddt_sync_flush_entry(ddt, &ddlwe,
ddlwe.ddlwe_type, ddlwe.ddlwe_class, tx);
/* End this pass if we've synced as much as we need to. */
if (++count >= nentries)
break;
}
ddt->ddt_flush_count += count;
ddt->ddt_flush_min -= count;
if (avl_is_empty(&ddt->ddt_log_flushing->ddl_tree)) {
/* We emptied it, so truncate on-disk */
DDT_KSTAT_ZERO(ddt, dds_log_flushing_entries);
ddt_log_truncate(ddt, tx);
/* No more passes needed this txg */
ddt->ddt_flush_pass = 0;
} else {
/* More to do next time, save checkpoint */
DDT_KSTAT_SUB(ddt, dds_log_flushing_entries, count);
ddt_log_checkpoint(ddt, &ddlwe, tx);
}
ddt_sync_update_stats(ddt, tx);
return (ddt->ddt_flush_pass == 0);
}
static inline void
ddt_flush_force_update_txg(ddt_t *ddt, uint64_t txg)
{
/*
* If we're not forcing flush, and not being asked to start, then
* there's nothing more to do.
*/
if (txg == 0) {
/* Update requested, are we currently forcing flush? */
if (ddt->ddt_flush_force_txg == 0)
return;
txg = ddt->ddt_flush_force_txg;
}
/*
* If either of the logs have entries unflushed entries before
* the wanted txg, set the force txg, otherwise clear it.
*/
if ((!avl_is_empty(&ddt->ddt_log_active->ddl_tree) &&
ddt->ddt_log_active->ddl_first_txg <= txg) ||
(!avl_is_empty(&ddt->ddt_log_flushing->ddl_tree) &&
ddt->ddt_log_flushing->ddl_first_txg <= txg)) {
ddt->ddt_flush_force_txg = txg;
return;
}
/*
* Nothing to flush behind the given txg, so we can clear force flush
* state.
*/
ddt->ddt_flush_force_txg = 0;
}
static void
ddt_sync_flush_log(ddt_t *ddt, dmu_tx_t *tx)
{
ASSERT(avl_is_empty(&ddt->ddt_tree));
/* Don't do any flushing when the pool is ready to shut down */
if (tx->tx_txg > spa_final_dirty_txg(ddt->ddt_spa))
return;
/* Try to flush some. */
if (!ddt_sync_flush_log_incremental(ddt, tx))
/* More to do next time */
return;
/* No more flushing this txg, so we can do end-of-txg housekeeping */
if (avl_is_empty(&ddt->ddt_log_flushing->ddl_tree) &&
!avl_is_empty(&ddt->ddt_log_active->ddl_tree)) {
/*
* No more to flush, and the active list has stuff, so
* try to swap the logs for next time.
*/
if (ddt_log_swap(ddt, tx)) {
DDT_KSTAT_ZERO(ddt, dds_log_active_entries);
DDT_KSTAT_SET(ddt, dds_log_flushing_entries,
avl_numnodes(&ddt->ddt_log_flushing->ddl_tree));
}
}
/* If force flush is no longer necessary, turn it off. */
ddt_flush_force_update_txg(ddt, 0);
/*
* Update flush rate. This is an exponential weighted moving average of
* the number of entries flushed over recent txgs.
*/
ddt->ddt_log_flush_rate = _ewma(
ddt->ddt_flush_count, ddt->ddt_log_flush_rate,
zfs_dedup_log_flush_flow_rate_txgs);
DDT_KSTAT_SET(ddt, dds_log_flush_rate, ddt->ddt_log_flush_rate);
/*
* Update flush time rate. This is an exponential weighted moving
* average of the total time taken to flush over recent txgs.
*/
ddt->ddt_log_flush_time_rate = _ewma(
ddt->ddt_log_flush_time_rate,
((int32_t)(NSEC2MSEC(gethrtime() - ddt->ddt_flush_start))),
zfs_dedup_log_flush_flow_rate_txgs);
DDT_KSTAT_SET(ddt, dds_log_flush_time_rate,
ddt->ddt_log_flush_time_rate);
}
static void
ddt_sync_table_log(ddt_t *ddt, dmu_tx_t *tx)
{
uint64_t count = avl_numnodes(&ddt->ddt_tree);
if (count > 0) {
ddt_log_update_t dlu = {0};
ddt_log_begin(ddt, count, tx, &dlu);
ddt_entry_t *dde;
void *cookie = NULL;
ddt_lightweight_entry_t ddlwe;
while ((dde =
avl_destroy_nodes(&ddt->ddt_tree, &cookie)) != NULL) {
ASSERT(dde->dde_flags & DDE_FLAG_LOADED);
DDT_ENTRY_TO_LIGHTWEIGHT(ddt, dde, &ddlwe);
ddt_log_entry(ddt, &ddlwe, &dlu);
ddt_sync_scan_entry(ddt, &ddlwe, tx);
ddt_free(ddt, dde);
}
ddt_log_commit(ddt, &dlu);
DDT_KSTAT_SET(ddt, dds_log_active_entries,
avl_numnodes(&ddt->ddt_log_active->ddl_tree));
/*
* Sync the stats for the store objects. Even though we haven't
* modified anything on those objects, they're no longer the
* source of truth for entries that are now in the log, and we
* need the on-disk counts to reflect that, otherwise we'll
* miscount later when importing.
*/
for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
for (ddt_class_t class = 0;
class < DDT_CLASSES; class++) {
if (ddt_object_exists(ddt, type, class))
ddt_object_sync(ddt, type, class, tx);
}
}
memcpy(&ddt->ddt_histogram_cache, ddt->ddt_histogram,
sizeof (ddt->ddt_histogram));
ddt->ddt_spa->spa_dedup_dspace = ~0ULL;
ddt->ddt_spa->spa_dedup_dsize = ~0ULL;
}
if (spa_sync_pass(ddt->ddt_spa) == 1) {
/*
* Update ingest rate. This is an exponential weighted moving
* average of the number of entries changed over recent txgs.
* The ramp-up cost shouldn't matter too much because the
* flusher will be trying to take at least the minimum anyway.
*/
ddt->ddt_log_ingest_rate = _ewma(
count, ddt->ddt_log_ingest_rate,
zfs_dedup_log_flush_flow_rate_txgs);
DDT_KSTAT_SET(ddt, dds_log_ingest_rate,
ddt->ddt_log_ingest_rate);
}
}
static void
ddt_sync_table_flush(ddt_t *ddt, dmu_tx_t *tx)
{
if (avl_numnodes(&ddt->ddt_tree) == 0)
return;
ddt_entry_t *dde;
void *cookie = NULL;
while ((dde = avl_destroy_nodes(
&ddt->ddt_tree, &cookie)) != NULL) {
ASSERT(dde->dde_flags & DDE_FLAG_LOADED);
ddt_lightweight_entry_t ddlwe;
DDT_ENTRY_TO_LIGHTWEIGHT(ddt, dde, &ddlwe);
ddt_sync_flush_entry(ddt, &ddlwe,
dde->dde_type, dde->dde_class, tx);
ddt_sync_scan_entry(ddt, &ddlwe, tx);
ddt_free(ddt, dde);
}
memcpy(&ddt->ddt_histogram_cache, ddt->ddt_histogram,
sizeof (ddt->ddt_histogram));
ddt->ddt_spa->spa_dedup_dspace = ~0ULL;
ddt->ddt_spa->spa_dedup_dsize = ~0ULL;
ddt_sync_update_stats(ddt, tx);
}
static void
ddt_sync_table(ddt_t *ddt, dmu_tx_t *tx)
{
spa_t *spa = ddt->ddt_spa;
if (ddt->ddt_version == UINT64_MAX)
return;
if (spa->spa_uberblock.ub_version < SPA_VERSION_DEDUP) {
ASSERT0(avl_numnodes(&ddt->ddt_tree));
return;
}
if (spa->spa_ddt_stat_object == 0) {
spa->spa_ddt_stat_object = zap_create_link(ddt->ddt_os,
DMU_OT_DDT_STATS, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_DDT_STATS, tx);
}
if (ddt->ddt_version == DDT_VERSION_FDT && ddt->ddt_dir_object == 0)
ddt_create_dir(ddt, tx);
if (ddt->ddt_flags & DDT_FLAG_LOG)
ddt_sync_table_log(ddt, tx);
else
ddt_sync_table_flush(ddt, tx);
}
void
ddt_sync(spa_t *spa, uint64_t txg)
{
dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan;
dmu_tx_t *tx;
zio_t *rio;
ASSERT3U(spa_syncing_txg(spa), ==, txg);
tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
rio = zio_root(spa, NULL, NULL,
ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SELF_HEAL);
/*
* This function may cause an immediate scan of ddt blocks (see
* the comment above dsl_scan_ddt() for details). We set the
* scan's root zio here so that we can wait for any scan IOs in
* addition to the regular ddt IOs.
*/
ASSERT3P(scn->scn_zio_root, ==, NULL);
scn->scn_zio_root = rio;
for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
ddt_t *ddt = spa->spa_ddt[c];
if (ddt == NULL)
continue;
ddt_sync_table(ddt, tx);
if (ddt->ddt_flags & DDT_FLAG_LOG)
ddt_sync_flush_log(ddt, tx);
ddt_repair_table(ddt, rio);
}
(void) zio_wait(rio);
scn->scn_zio_root = NULL;
dmu_tx_commit(tx);
}
void
ddt_walk_init(spa_t *spa, uint64_t txg)
{
if (txg == 0)
txg = spa_syncing_txg(spa);
for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
ddt_t *ddt = spa->spa_ddt[c];
if (ddt == NULL || !(ddt->ddt_flags & DDT_FLAG_LOG))
continue;
ddt_enter(ddt);
ddt_flush_force_update_txg(ddt, txg);
ddt_exit(ddt);
}
}
boolean_t
ddt_walk_ready(spa_t *spa)
{
for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
ddt_t *ddt = spa->spa_ddt[c];
if (ddt == NULL || !(ddt->ddt_flags & DDT_FLAG_LOG))
continue;
if (ddt->ddt_flush_force_txg > 0)
return (B_FALSE);
}
return (B_TRUE);
}
static int
ddt_walk_impl(spa_t *spa, ddt_bookmark_t *ddb, ddt_lightweight_entry_t *ddlwe,
uint64_t flags, boolean_t wait)
{
do {
do {
do {
ddt_t *ddt = spa->spa_ddt[ddb->ddb_checksum];
if (ddt == NULL)
continue;
if (flags != 0 &&
(ddt->ddt_flags & flags) != flags)
continue;
if (wait && ddt->ddt_flush_force_txg > 0)
return (EAGAIN);
int error = ENOENT;
if (ddt_object_exists(ddt, ddb->ddb_type,
ddb->ddb_class)) {
error = ddt_object_walk(ddt,
ddb->ddb_type, ddb->ddb_class,
&ddb->ddb_cursor, ddlwe);
}
if (error == 0)
return (0);
if (error != ENOENT)
return (error);
ddb->ddb_cursor = 0;
} while (++ddb->ddb_checksum < ZIO_CHECKSUM_FUNCTIONS);
ddb->ddb_checksum = 0;
} while (++ddb->ddb_type < DDT_TYPES);
ddb->ddb_type = 0;
} while (++ddb->ddb_class < DDT_CLASSES);
return (SET_ERROR(ENOENT));
}
int
ddt_walk(spa_t *spa, ddt_bookmark_t *ddb, ddt_lightweight_entry_t *ddlwe)
{
return (ddt_walk_impl(spa, ddb, ddlwe, 0, B_TRUE));
}
/*
* This function is used by Block Cloning (brt.c) to increase reference
* counter for the DDT entry if the block is already in DDT.
*
* Return false if the block, despite having the D bit set, is not present
* in the DDT. This is possible when the DDT has been pruned by an admin
* or by the DDT quota mechanism.
*/
boolean_t
ddt_addref(spa_t *spa, const blkptr_t *bp)
{
ddt_t *ddt;
ddt_entry_t *dde;
boolean_t result;
spa_config_enter(spa, SCL_ZIO, FTAG, RW_READER);
ddt = ddt_select(spa, bp);
ddt_enter(ddt);
dde = ddt_lookup(ddt, bp);
/* Can be NULL if the entry for this block was pruned. */
if (dde == NULL) {
ddt_exit(ddt);
spa_config_exit(spa, SCL_ZIO, FTAG);
return (B_FALSE);
}
if ((dde->dde_type < DDT_TYPES) || (dde->dde_flags & DDE_FLAG_LOGGED)) {
/*
* This entry was either synced to a store object (dde_type is
* real) or was logged. It must be properly on disk at this
* point, so we can just bump its refcount.
*/
int p = DDT_PHYS_FOR_COPIES(ddt, BP_GET_NDVAS(bp));
ddt_phys_variant_t v = DDT_PHYS_VARIANT(ddt, p);
ddt_phys_addref(dde->dde_phys, v);
result = B_TRUE;
} else {
/*
* If the block has the DEDUP flag set it still might not
* exist in the DEDUP table due to DDT pruning of entries
* where refcnt=1.
*/
ddt_remove(ddt, dde);
result = B_FALSE;
}
ddt_exit(ddt);
spa_config_exit(spa, SCL_ZIO, FTAG);
return (result);
}
typedef struct ddt_prune_entry {
ddt_t *dpe_ddt;
ddt_key_t dpe_key;
list_node_t dpe_node;
ddt_univ_phys_t dpe_phys[];
} ddt_prune_entry_t;
typedef struct ddt_prune_info {
spa_t *dpi_spa;
uint64_t dpi_txg_syncs;
uint64_t dpi_pruned;
list_t dpi_candidates;
} ddt_prune_info_t;
/*
* Add prune candidates for ddt_sync during spa_sync
*/
static void
prune_candidates_sync(void *arg, dmu_tx_t *tx)
{
(void) tx;
ddt_prune_info_t *dpi = arg;
ddt_prune_entry_t *dpe;
spa_config_enter(dpi->dpi_spa, SCL_ZIO, FTAG, RW_READER);
/* Process the prune candidates collected so far */
while ((dpe = list_remove_head(&dpi->dpi_candidates)) != NULL) {
blkptr_t blk;
ddt_t *ddt = dpe->dpe_ddt;
ddt_enter(ddt);
/*
* If it's on the live list, then it was loaded for update
* this txg and is no longer stale; skip it.
*/
if (avl_find(&ddt->ddt_tree, &dpe->dpe_key, NULL)) {
ddt_exit(ddt);
kmem_free(dpe, sizeof (*dpe));
continue;
}
ddt_bp_create(ddt->ddt_checksum, &dpe->dpe_key,
dpe->dpe_phys, DDT_PHYS_FLAT, &blk);
ddt_entry_t *dde = ddt_lookup(ddt, &blk);
if (dde != NULL && !(dde->dde_flags & DDE_FLAG_LOGGED)) {
ASSERT(dde->dde_flags & DDE_FLAG_LOADED);
/*
* Zero the physical, so we don't try to free DVAs
* at flush nor try to reuse this entry.
*/
ddt_phys_clear(dde->dde_phys, DDT_PHYS_FLAT);
dpi->dpi_pruned++;
}
ddt_exit(ddt);
kmem_free(dpe, sizeof (*dpe));
}
spa_config_exit(dpi->dpi_spa, SCL_ZIO, FTAG);
dpi->dpi_txg_syncs++;
}
/*
* Prune candidates are collected in open context and processed
* in sync context as part of ddt_sync_table().
*/
static void
ddt_prune_entry(list_t *list, ddt_t *ddt, const ddt_key_t *ddk,
const ddt_univ_phys_t *ddp)
{
ASSERT(ddt->ddt_flags & DDT_FLAG_FLAT);
size_t dpe_size = sizeof (ddt_prune_entry_t) + DDT_FLAT_PHYS_SIZE;
ddt_prune_entry_t *dpe = kmem_alloc(dpe_size, KM_SLEEP);
dpe->dpe_ddt = ddt;
dpe->dpe_key = *ddk;
memcpy(dpe->dpe_phys, ddp, DDT_FLAT_PHYS_SIZE);
list_insert_head(list, dpe);
}
/*
* Interate over all the entries in the DDT unique class.
* The walk will perform one of the following operations:
* (a) build a histogram than can be used when pruning
* (b) prune entries older than the cutoff
*
* Also called by zdb(8) to dump the age histogram
*/
void
ddt_prune_walk(spa_t *spa, uint64_t cutoff, ddt_age_histo_t *histogram)
{
ddt_bookmark_t ddb = {
.ddb_class = DDT_CLASS_UNIQUE,
.ddb_type = 0,
.ddb_checksum = 0,
.ddb_cursor = 0
};
ddt_lightweight_entry_t ddlwe = {0};
int error;
int valid = 0;
int candidates = 0;
uint64_t now = gethrestime_sec();
ddt_prune_info_t dpi;
boolean_t pruning = (cutoff != 0);
if (pruning) {
dpi.dpi_txg_syncs = 0;
dpi.dpi_pruned = 0;
dpi.dpi_spa = spa;
list_create(&dpi.dpi_candidates, sizeof (ddt_prune_entry_t),
offsetof(ddt_prune_entry_t, dpe_node));
}
if (histogram != NULL)
memset(histogram, 0, sizeof (ddt_age_histo_t));
while ((error =
ddt_walk_impl(spa, &ddb, &ddlwe, DDT_FLAG_FLAT, B_FALSE)) == 0) {
ddt_t *ddt = spa->spa_ddt[ddb.ddb_checksum];
VERIFY(ddt);
if (spa_shutting_down(spa) || issig())
break;
ASSERT(ddt->ddt_flags & DDT_FLAG_FLAT);
ASSERT3U(ddlwe.ddlwe_phys.ddp_flat.ddp_refcnt, <=, 1);
uint64_t class_start =
ddlwe.ddlwe_phys.ddp_flat.ddp_class_start;
/*
* If this entry is on the log, then the stored entry is stale
* and we should skip it.
*/
if (ddt_log_find_key(ddt, &ddlwe.ddlwe_key, NULL))
continue;
/* prune older entries */
if (pruning && class_start < cutoff) {
if (candidates++ >= zfs_ddt_prunes_per_txg) {
/* sync prune candidates in batches */
VERIFY0(dsl_sync_task(spa_name(spa),
NULL, prune_candidates_sync,
&dpi, 0, ZFS_SPACE_CHECK_NONE));
candidates = 1;
}
ddt_prune_entry(&dpi.dpi_candidates, ddt,
&ddlwe.ddlwe_key, &ddlwe.ddlwe_phys);
}
/* build a histogram */
if (histogram != NULL) {
uint64_t age = MAX(1, (now - class_start) / 3600);
int bin = MIN(highbit64(age) - 1, HIST_BINS - 1);
histogram->dah_entries++;
histogram->dah_age_histo[bin]++;
}
valid++;
}
if (pruning && valid > 0) {
if (!list_is_empty(&dpi.dpi_candidates)) {
/* sync out final batch of prune candidates */
VERIFY0(dsl_sync_task(spa_name(spa), NULL,
prune_candidates_sync, &dpi, 0,
ZFS_SPACE_CHECK_NONE));
}
list_destroy(&dpi.dpi_candidates);
zfs_dbgmsg("pruned %llu entries (%d%%) across %llu txg syncs",
(u_longlong_t)dpi.dpi_pruned,
(int)((dpi.dpi_pruned * 100) / valid),
(u_longlong_t)dpi.dpi_txg_syncs);
}
}
static uint64_t
ddt_total_entries(spa_t *spa)
{
ddt_object_t ddo;
ddt_get_dedup_object_stats(spa, &ddo);
return (ddo.ddo_count);
}
int
ddt_prune_unique_entries(spa_t *spa, zpool_ddt_prune_unit_t unit,
uint64_t amount)
{
uint64_t cutoff;
uint64_t start_time = gethrtime();
if (spa->spa_active_ddt_prune)
return (SET_ERROR(EALREADY));
if (ddt_total_entries(spa) == 0)
return (0);
spa->spa_active_ddt_prune = B_TRUE;
zfs_dbgmsg("prune %llu %s", (u_longlong_t)amount,
unit == ZPOOL_DDT_PRUNE_PERCENTAGE ? "%" : "seconds old or older");
if (unit == ZPOOL_DDT_PRUNE_PERCENTAGE) {
ddt_age_histo_t histogram;
uint64_t oldest = 0;
/* Make a pass over DDT to build a histogram */
ddt_prune_walk(spa, 0, &histogram);
int target = (histogram.dah_entries * amount) / 100;
/*
* Figure out our cutoff date
* (i.e., which bins to prune from)
*/
for (int i = HIST_BINS - 1; i >= 0 && target > 0; i--) {
if (histogram.dah_age_histo[i] != 0) {
/* less than this bucket remaining */
if (target < histogram.dah_age_histo[i]) {
oldest = MAX(1, (1<<i) * 3600);
target = 0;
} else {
target -= histogram.dah_age_histo[i];
}
}
}
cutoff = gethrestime_sec() - oldest;
if (ddt_dump_prune_histogram)
ddt_dump_age_histogram(&histogram, cutoff);
} else if (unit == ZPOOL_DDT_PRUNE_AGE) {
cutoff = gethrestime_sec() - amount;
} else {
return (EINVAL);
}
if (cutoff > 0 && !spa_shutting_down(spa) && !issig()) {
/* Traverse DDT to prune entries older that our cuttoff */
ddt_prune_walk(spa, cutoff, NULL);
}
zfs_dbgmsg("%s: prune completed in %llu ms",
spa_name(spa), (u_longlong_t)NSEC2MSEC(gethrtime() - start_time));
spa->spa_active_ddt_prune = B_FALSE;
return (0);
}
ZFS_MODULE_PARAM(zfs_dedup, zfs_dedup_, prefetch, INT, ZMOD_RW,
"Enable prefetching dedup-ed blks");
ZFS_MODULE_PARAM(zfs_dedup, zfs_dedup_, log_flush_passes_max, UINT, ZMOD_RW,
"Max number of incremental dedup log flush passes per transaction");
ZFS_MODULE_PARAM(zfs_dedup, zfs_dedup_, log_flush_min_time_ms, UINT, ZMOD_RW,
"Min time to spend on incremental dedup log flush each transaction");
ZFS_MODULE_PARAM(zfs_dedup, zfs_dedup_, log_flush_entries_min, UINT, ZMOD_RW,
"Min number of log entries to flush each transaction");
ZFS_MODULE_PARAM(zfs_dedup, zfs_dedup_, log_flush_flow_rate_txgs, UINT, ZMOD_RW,
"Number of txgs to average flow rates across");
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