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mirror_zfs/module/zfs/dsl_deadlist.c
Paul Dagnelie ca5777793e Reduce loaded range tree memory usage 
This patch implements a new tree structure for ZFS, and uses it to 
store range trees more efficiently.

The new structure is approximately a B-tree, though there are some 
small differences from the usual characterizations. The tree has core 
nodes and leaf nodes; each contain data elements, which the elements 
in the core nodes acting as separators between its children. The 
difference between core and leaf nodes is that the core nodes have an 
array of children, while leaf nodes don't. Every node in the tree may 
be only partially full; in most cases, they are all at least 50% full 
(in terms of element count) except for the root node, which can be 
less full. Underfull nodes will steal from their neighbors or merge to 
remain full enough, while overfull nodes will split in two. The data 
elements are contained in tree-controlled buffers; they are copied 
into these on insertion, and overwritten on deletion. This means that 
the elements are not independently allocated, which reduces overhead, 
but also means they can't be shared between trees (and also that 
pointers to them are only valid until a side-effectful tree operation 
occurs). The overhead varies based on how dense the tree is, but is 
usually on the order of about 50% of the element size; the per-node 
overheads are very small, and so don't make a significant difference. 
The trees can accept arbitrary records; they accept a size and a 
comparator to allow them to be used for a variety of purposes.

The new trees replace the AVL trees used in the range trees today. 
Currently, the range_seg_t structure contains three 8 byte integers 
of payload and two 24 byte avl_tree_node_ts to handle its storage in 
both an offset-sorted tree and a size-sorted tree (total size: 64 
bytes). In the new model, the range seg structures are usually two 4 
byte integers, but a separate one needs to exist for the size-sorted 
and offset-sorted tree. Between the raw size, the 50% overhead, and 
the double storage, the new btrees are expected to use 8*1.5*2 = 24 
bytes per record, or 33.3% as much memory as the AVL trees (this is 
for the purposes of storing metaslab range trees; for other purposes, 
like scrubs, they use ~50% as much memory).

We reduced the size of the payload in the range segments by teaching 
range trees about starting offsets and shifts; since metaslabs have a 
fixed starting offset, and they all operate in terms of disk sectors, 
we can store the ranges using 4-byte integers as long as the size of 
the metaslab divided by the sector size is less than 2^32. For 512-byte
sectors, this is a 2^41 (or 2TB) metaslab, which with the default
settings corresponds to a 256PB disk. 4k sector disks can handle 
metaslabs up to 2^46 bytes, or 2^63 byte disks. Since we do not 
anticipate disks of this size in the near future, there should be 
almost no cases where metaslabs need 64-byte integers to store their 
ranges. We do still have the capability to store 64-byte integer ranges 
to account for cases where we are storing per-vdev (or per-dnode) trees, 
which could reasonably go above the limits discussed. We also do not 
store fill information in the compact version of the node, since it 
is only used for sorted scrub.

We also optimized the metaslab loading process in various other ways
to offset some inefficiencies in the btree model. While individual
operations (find, insert, remove_from) are faster for the btree than 
they are for the avl tree, remove usually requires a find operation, 
while in the AVL tree model the element itself suffices. Some clever 
changes actually caused an overall speedup in metaslab loading; we use 
approximately 40% less cpu to load metaslabs in our tests on Illumos.

Another memory and performance optimization was achieved by changing 
what is stored in the size-sorted trees. When a disk is heavily 
fragmented, the df algorithm used by default in ZFS will almost always 
find a number of small regions in its initial cursor-based search; it 
will usually only fall back to the size-sorted tree to find larger 
regions. If we increase the size of the cursor-based search slightly, 
and don't store segments that are smaller than a tunable size floor 
in the size-sorted tree, we can further cut memory usage down to 
below 20% of what the AVL trees store. This also results in further 
reductions in CPU time spent loading metaslabs.

The 16KiB size floor was chosen because it results in substantial memory 
usage reduction while not usually resulting in situations where we can't 
find an appropriate chunk with the cursor and are forced to use an 
oversized chunk from the size-sorted tree. In addition, even if we do 
have to use an oversized chunk from the size-sorted tree, the chunk 
would be too small to use for ZIL allocations, so it isn't as big of a 
loss as it might otherwise be. And often, more small allocations will 
follow the initial one, and the cursor search will now find the 
remainder of the chunk we didn't use all of and use it for subsequent 
allocations. Practical testing has shown little or no change in 
fragmentation as a result of this change.

If the size-sorted tree becomes empty while the offset sorted one still 
has entries, it will load all the entries from the offset sorted tree 
and disregard the size floor until it is unloaded again. This operation 
occurs rarely with the default setting, only on incredibly thoroughly 
fragmented pools.

There are some other small changes to zdb to teach it to handle btrees, 
but nothing major.
                                           
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed by: Sebastien Roy seb@delphix.com
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #9181
2019-10-09 10:36:03 -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 http://www.opensolaris.org/os/licensing.
* 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) 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2019 by Delphix. All rights reserved.
* Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
*/
#include <sys/dmu.h>
#include <sys/refcount.h>
#include <sys/zap.h>
#include <sys/zfs_context.h>
#include <sys/dsl_pool.h>
#include <sys/dsl_dataset.h>
/*
* Deadlist concurrency:
*
* Deadlists can only be modified from the syncing thread.
*
* Except for dsl_deadlist_insert(), it can only be modified with the
* dp_config_rwlock held with RW_WRITER.
*
* The accessors (dsl_deadlist_space() and dsl_deadlist_space_range()) can
* be called concurrently, from open context, with the dl_config_rwlock held
* with RW_READER.
*
* Therefore, we only need to provide locking between dsl_deadlist_insert() and
* the accessors, protecting:
* dl_phys->dl_used,comp,uncomp
* and protecting the dl_tree from being loaded.
* The locking is provided by dl_lock. Note that locking on the bpobj_t
* provides its own locking, and dl_oldfmt is immutable.
*/
/*
* Livelist Overview
* ================
*
* Livelists use the same 'deadlist_t' struct as deadlists and are also used
* to track blkptrs over the lifetime of a dataset. Livelists however, belong
* to clones and track the blkptrs that are clone-specific (were born after
* the clone's creation). The exception is embedded block pointers which are
* not included in livelists because they do not need to be freed.
*
* When it comes time to delete the clone, the livelist provides a quick
* reference as to what needs to be freed. For this reason, livelists also track
* when clone-specific blkptrs are freed before deletion to prevent double
* frees. Each blkptr in a livelist is marked as a FREE or an ALLOC and the
* deletion algorithm iterates backwards over the livelist, matching
* FREE/ALLOC pairs and then freeing those ALLOCs which remain. livelists
* are also updated in the case when blkptrs are remapped: the old version
* of the blkptr is cancelled out with a FREE and the new version is tracked
* with an ALLOC.
*
* To bound the amount of memory required for deletion, livelists over a
* certain size are spread over multiple entries. Entries are grouped by
* birth txg so we can be sure the ALLOC/FREE pair for a given blkptr will
* be in the same entry. This allows us to delete livelists incrementally
* over multiple syncs, one entry at a time.
*
* During the lifetime of the clone, livelists can get extremely large.
* Their size is managed by periodic condensing (preemptively cancelling out
* FREE/ALLOC pairs). Livelists are disabled when a clone is promoted or when
* the shared space between the clone and its origin is so small that it
* doesn't make sense to use livelists anymore.
*/
/*
* The threshold sublist size at which we create a new sub-livelist for the
* next txg. However, since blkptrs of the same transaction group must be in
* the same sub-list, the actual sublist size may exceed this. When picking the
* size we had to balance the fact that larger sublists mean fewer sublists
* (decreasing the cost of insertion) against the consideration that sublists
* will be loaded into memory and shouldn't take up an inordinate amount of
* space. We settled on ~500000 entries, corresponding to roughly 128M.
*/
unsigned long zfs_livelist_max_entries = 500000;
/*
* We can approximate how much of a performance gain a livelist will give us
* based on the percentage of blocks shared between the clone and its origin.
* 0 percent shared means that the clone has completely diverged and that the
* old method is maximally effective: every read from the block tree will
* result in lots of frees. Livelists give us gains when they track blocks
* scattered across the tree, when one read in the old method might only
* result in a few frees. Once the clone has been overwritten enough,
* writes are no longer sparse and we'll no longer get much of a benefit from
* tracking them with a livelist. We chose a lower limit of 75 percent shared
* (25 percent overwritten). This means that 1/4 of all block pointers will be
* freed (e.g. each read frees 256, out of a max of 1024) so we expect livelists
* to make deletion 4x faster. Once the amount of shared space drops below this
* threshold, the clone will revert to the old deletion method.
*/
int zfs_livelist_min_percent_shared = 75;
static int
dsl_deadlist_compare(const void *arg1, const void *arg2)
{
const dsl_deadlist_entry_t *dle1 = arg1;
const dsl_deadlist_entry_t *dle2 = arg2;
return (TREE_CMP(dle1->dle_mintxg, dle2->dle_mintxg));
}
static int
dsl_deadlist_cache_compare(const void *arg1, const void *arg2)
{
const dsl_deadlist_cache_entry_t *dlce1 = arg1;
const dsl_deadlist_cache_entry_t *dlce2 = arg2;
return (TREE_CMP(dlce1->dlce_mintxg, dlce2->dlce_mintxg));
}
static void
dsl_deadlist_load_tree(dsl_deadlist_t *dl)
{
zap_cursor_t zc;
zap_attribute_t za;
ASSERT(MUTEX_HELD(&dl->dl_lock));
ASSERT(!dl->dl_oldfmt);
if (dl->dl_havecache) {
/*
* After loading the tree, the caller may modify the tree,
* e.g. to add or remove nodes, or to make a node no longer
* refer to the empty_bpobj. These changes would make the
* dl_cache incorrect. Therefore we discard the cache here,
* so that it can't become incorrect.
*/
dsl_deadlist_cache_entry_t *dlce;
void *cookie = NULL;
while ((dlce = avl_destroy_nodes(&dl->dl_cache, &cookie))
!= NULL) {
kmem_free(dlce, sizeof (*dlce));
}
avl_destroy(&dl->dl_cache);
dl->dl_havecache = B_FALSE;
}
if (dl->dl_havetree)
return;
avl_create(&dl->dl_tree, dsl_deadlist_compare,
sizeof (dsl_deadlist_entry_t),
offsetof(dsl_deadlist_entry_t, dle_node));
for (zap_cursor_init(&zc, dl->dl_os, dl->dl_object);
zap_cursor_retrieve(&zc, &za) == 0;
zap_cursor_advance(&zc)) {
dsl_deadlist_entry_t *dle = kmem_alloc(sizeof (*dle), KM_SLEEP);
dle->dle_mintxg = zfs_strtonum(za.za_name, NULL);
/*
* Prefetch all the bpobj's so that we do that i/o
* in parallel. Then open them all in a second pass.
*/
dle->dle_bpobj.bpo_object = za.za_first_integer;
dmu_prefetch(dl->dl_os, dle->dle_bpobj.bpo_object,
0, 0, 0, ZIO_PRIORITY_SYNC_READ);
avl_add(&dl->dl_tree, dle);
}
zap_cursor_fini(&zc);
for (dsl_deadlist_entry_t *dle = avl_first(&dl->dl_tree);
dle != NULL; dle = AVL_NEXT(&dl->dl_tree, dle)) {
VERIFY0(bpobj_open(&dle->dle_bpobj, dl->dl_os,
dle->dle_bpobj.bpo_object));
}
dl->dl_havetree = B_TRUE;
}
/*
* Load only the non-empty bpobj's into the dl_cache. The cache is an analog
* of the dl_tree, but contains only non-empty_bpobj nodes from the ZAP. It
* is used only for gathering space statistics. The dl_cache has two
* advantages over the dl_tree:
*
* 1. Loading the dl_cache is ~5x faster than loading the dl_tree (if it's
* mostly empty_bpobj's), due to less CPU overhead to open the empty_bpobj
* many times and to inquire about its (zero) space stats many times.
*
* 2. The dl_cache uses less memory than the dl_tree. We only need to load
* the dl_tree of snapshots when deleting a snapshot, after which we free the
* dl_tree with dsl_deadlist_discard_tree
*/
static void
dsl_deadlist_load_cache(dsl_deadlist_t *dl)
{
zap_cursor_t zc;
zap_attribute_t za;
ASSERT(MUTEX_HELD(&dl->dl_lock));
ASSERT(!dl->dl_oldfmt);
if (dl->dl_havecache)
return;
uint64_t empty_bpobj = dmu_objset_pool(dl->dl_os)->dp_empty_bpobj;
avl_create(&dl->dl_cache, dsl_deadlist_cache_compare,
sizeof (dsl_deadlist_cache_entry_t),
offsetof(dsl_deadlist_cache_entry_t, dlce_node));
for (zap_cursor_init(&zc, dl->dl_os, dl->dl_object);
zap_cursor_retrieve(&zc, &za) == 0;
zap_cursor_advance(&zc)) {
if (za.za_first_integer == empty_bpobj)
continue;
dsl_deadlist_cache_entry_t *dlce =
kmem_zalloc(sizeof (*dlce), KM_SLEEP);
dlce->dlce_mintxg = zfs_strtonum(za.za_name, NULL);
/*
* Prefetch all the bpobj's so that we do that i/o
* in parallel. Then open them all in a second pass.
*/
dlce->dlce_bpobj = za.za_first_integer;
dmu_prefetch(dl->dl_os, dlce->dlce_bpobj,
0, 0, 0, ZIO_PRIORITY_SYNC_READ);
avl_add(&dl->dl_cache, dlce);
}
zap_cursor_fini(&zc);
for (dsl_deadlist_cache_entry_t *dlce = avl_first(&dl->dl_cache);
dlce != NULL; dlce = AVL_NEXT(&dl->dl_cache, dlce)) {
bpobj_t bpo;
VERIFY0(bpobj_open(&bpo, dl->dl_os, dlce->dlce_bpobj));
VERIFY0(bpobj_space(&bpo,
&dlce->dlce_bytes, &dlce->dlce_comp, &dlce->dlce_uncomp));
bpobj_close(&bpo);
}
dl->dl_havecache = B_TRUE;
}
/*
* Discard the tree to save memory.
*/
void
dsl_deadlist_discard_tree(dsl_deadlist_t *dl)
{
mutex_enter(&dl->dl_lock);
if (!dl->dl_havetree) {
mutex_exit(&dl->dl_lock);
return;
}
dsl_deadlist_entry_t *dle;
void *cookie = NULL;
while ((dle = avl_destroy_nodes(&dl->dl_tree, &cookie)) != NULL) {
bpobj_close(&dle->dle_bpobj);
kmem_free(dle, sizeof (*dle));
}
avl_destroy(&dl->dl_tree);
dl->dl_havetree = B_FALSE;
mutex_exit(&dl->dl_lock);
}
void
dsl_deadlist_iterate(dsl_deadlist_t *dl, deadlist_iter_t func, void *args)
{
dsl_deadlist_entry_t *dle;
ASSERT(dsl_deadlist_is_open(dl));
mutex_enter(&dl->dl_lock);
dsl_deadlist_load_tree(dl);
mutex_exit(&dl->dl_lock);
for (dle = avl_first(&dl->dl_tree); dle != NULL;
dle = AVL_NEXT(&dl->dl_tree, dle)) {
if (func(args, dle) != 0)
break;
}
}
void
dsl_deadlist_open(dsl_deadlist_t *dl, objset_t *os, uint64_t object)
{
dmu_object_info_t doi;
ASSERT(!dsl_deadlist_is_open(dl));
mutex_init(&dl->dl_lock, NULL, MUTEX_DEFAULT, NULL);
dl->dl_os = os;
dl->dl_object = object;
VERIFY0(dmu_bonus_hold(os, object, dl, &dl->dl_dbuf));
dmu_object_info_from_db(dl->dl_dbuf, &doi);
if (doi.doi_type == DMU_OT_BPOBJ) {
dmu_buf_rele(dl->dl_dbuf, dl);
dl->dl_dbuf = NULL;
dl->dl_oldfmt = B_TRUE;
VERIFY0(bpobj_open(&dl->dl_bpobj, os, object));
return;
}
dl->dl_oldfmt = B_FALSE;
dl->dl_phys = dl->dl_dbuf->db_data;
dl->dl_havetree = B_FALSE;
dl->dl_havecache = B_FALSE;
}
boolean_t
dsl_deadlist_is_open(dsl_deadlist_t *dl)
{
return (dl->dl_os != NULL);
}
void
dsl_deadlist_close(dsl_deadlist_t *dl)
{
ASSERT(dsl_deadlist_is_open(dl));
mutex_destroy(&dl->dl_lock);
if (dl->dl_oldfmt) {
dl->dl_oldfmt = B_FALSE;
bpobj_close(&dl->dl_bpobj);
dl->dl_os = NULL;
dl->dl_object = 0;
return;
}
if (dl->dl_havetree) {
dsl_deadlist_entry_t *dle;
void *cookie = NULL;
while ((dle = avl_destroy_nodes(&dl->dl_tree, &cookie))
!= NULL) {
bpobj_close(&dle->dle_bpobj);
kmem_free(dle, sizeof (*dle));
}
avl_destroy(&dl->dl_tree);
}
if (dl->dl_havecache) {
dsl_deadlist_cache_entry_t *dlce;
void *cookie = NULL;
while ((dlce = avl_destroy_nodes(&dl->dl_cache, &cookie))
!= NULL) {
kmem_free(dlce, sizeof (*dlce));
}
avl_destroy(&dl->dl_cache);
}
dmu_buf_rele(dl->dl_dbuf, dl);
dl->dl_dbuf = NULL;
dl->dl_phys = NULL;
dl->dl_os = NULL;
dl->dl_object = 0;
}
uint64_t
dsl_deadlist_alloc(objset_t *os, dmu_tx_t *tx)
{
if (spa_version(dmu_objset_spa(os)) < SPA_VERSION_DEADLISTS)
return (bpobj_alloc(os, SPA_OLD_MAXBLOCKSIZE, tx));
return (zap_create(os, DMU_OT_DEADLIST, DMU_OT_DEADLIST_HDR,
sizeof (dsl_deadlist_phys_t), tx));
}
void
dsl_deadlist_free(objset_t *os, uint64_t dlobj, dmu_tx_t *tx)
{
dmu_object_info_t doi;
zap_cursor_t zc;
zap_attribute_t za;
VERIFY0(dmu_object_info(os, dlobj, &doi));
if (doi.doi_type == DMU_OT_BPOBJ) {
bpobj_free(os, dlobj, tx);
return;
}
for (zap_cursor_init(&zc, os, dlobj);
zap_cursor_retrieve(&zc, &za) == 0;
zap_cursor_advance(&zc)) {
uint64_t obj = za.za_first_integer;
if (obj == dmu_objset_pool(os)->dp_empty_bpobj)
bpobj_decr_empty(os, tx);
else
bpobj_free(os, obj, tx);
}
zap_cursor_fini(&zc);
VERIFY0(dmu_object_free(os, dlobj, tx));
}
static void
dle_enqueue(dsl_deadlist_t *dl, dsl_deadlist_entry_t *dle,
const blkptr_t *bp, boolean_t bp_freed, dmu_tx_t *tx)
{
ASSERT(MUTEX_HELD(&dl->dl_lock));
if (dle->dle_bpobj.bpo_object ==
dmu_objset_pool(dl->dl_os)->dp_empty_bpobj) {
uint64_t obj = bpobj_alloc(dl->dl_os, SPA_OLD_MAXBLOCKSIZE, tx);
bpobj_close(&dle->dle_bpobj);
bpobj_decr_empty(dl->dl_os, tx);
VERIFY0(bpobj_open(&dle->dle_bpobj, dl->dl_os, obj));
VERIFY0(zap_update_int_key(dl->dl_os, dl->dl_object,
dle->dle_mintxg, obj, tx));
}
bpobj_enqueue(&dle->dle_bpobj, bp, bp_freed, tx);
}
static void
dle_enqueue_subobj(dsl_deadlist_t *dl, dsl_deadlist_entry_t *dle,
uint64_t obj, dmu_tx_t *tx)
{
ASSERT(MUTEX_HELD(&dl->dl_lock));
if (dle->dle_bpobj.bpo_object !=
dmu_objset_pool(dl->dl_os)->dp_empty_bpobj) {
bpobj_enqueue_subobj(&dle->dle_bpobj, obj, tx);
} else {
bpobj_close(&dle->dle_bpobj);
bpobj_decr_empty(dl->dl_os, tx);
VERIFY0(bpobj_open(&dle->dle_bpobj, dl->dl_os, obj));
VERIFY0(zap_update_int_key(dl->dl_os, dl->dl_object,
dle->dle_mintxg, obj, tx));
}
}
void
dsl_deadlist_insert(dsl_deadlist_t *dl, const blkptr_t *bp, boolean_t bp_freed,
dmu_tx_t *tx)
{
dsl_deadlist_entry_t dle_tofind;
dsl_deadlist_entry_t *dle;
avl_index_t where;
if (dl->dl_oldfmt) {
bpobj_enqueue(&dl->dl_bpobj, bp, bp_freed, tx);
return;
}
mutex_enter(&dl->dl_lock);
dsl_deadlist_load_tree(dl);
dmu_buf_will_dirty(dl->dl_dbuf, tx);
int sign = bp_freed ? -1 : +1;
dl->dl_phys->dl_used +=
sign * bp_get_dsize_sync(dmu_objset_spa(dl->dl_os), bp);
dl->dl_phys->dl_comp += sign * BP_GET_PSIZE(bp);
dl->dl_phys->dl_uncomp += sign * BP_GET_UCSIZE(bp);
dle_tofind.dle_mintxg = bp->blk_birth;
dle = avl_find(&dl->dl_tree, &dle_tofind, &where);
if (dle == NULL)
dle = avl_nearest(&dl->dl_tree, where, AVL_BEFORE);
else
dle = AVL_PREV(&dl->dl_tree, dle);
if (dle == NULL) {
zfs_panic_recover("blkptr at %p has invalid BLK_BIRTH %llu",
bp, (longlong_t)bp->blk_birth);
dle = avl_first(&dl->dl_tree);
}
ASSERT3P(dle, !=, NULL);
dle_enqueue(dl, dle, bp, bp_freed, tx);
mutex_exit(&dl->dl_lock);
}
int
dsl_deadlist_insert_alloc_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
{
dsl_deadlist_t *dl = arg;
dsl_deadlist_insert(dl, bp, B_FALSE, tx);
return (0);
}
int
dsl_deadlist_insert_free_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
{
dsl_deadlist_t *dl = arg;
dsl_deadlist_insert(dl, bp, B_TRUE, tx);
return (0);
}
/*
* Insert new key in deadlist, which must be > all current entries.
* mintxg is not inclusive.
*/
void
dsl_deadlist_add_key(dsl_deadlist_t *dl, uint64_t mintxg, dmu_tx_t *tx)
{
uint64_t obj;
dsl_deadlist_entry_t *dle;
if (dl->dl_oldfmt)
return;
dle = kmem_alloc(sizeof (*dle), KM_SLEEP);
dle->dle_mintxg = mintxg;
mutex_enter(&dl->dl_lock);
dsl_deadlist_load_tree(dl);
obj = bpobj_alloc_empty(dl->dl_os, SPA_OLD_MAXBLOCKSIZE, tx);
VERIFY0(bpobj_open(&dle->dle_bpobj, dl->dl_os, obj));
avl_add(&dl->dl_tree, dle);
VERIFY0(zap_add_int_key(dl->dl_os, dl->dl_object,
mintxg, obj, tx));
mutex_exit(&dl->dl_lock);
}
/*
* Remove this key, merging its entries into the previous key.
*/
void
dsl_deadlist_remove_key(dsl_deadlist_t *dl, uint64_t mintxg, dmu_tx_t *tx)
{
dsl_deadlist_entry_t dle_tofind;
dsl_deadlist_entry_t *dle, *dle_prev;
if (dl->dl_oldfmt)
return;
mutex_enter(&dl->dl_lock);
dsl_deadlist_load_tree(dl);
dle_tofind.dle_mintxg = mintxg;
dle = avl_find(&dl->dl_tree, &dle_tofind, NULL);
ASSERT3P(dle, !=, NULL);
dle_prev = AVL_PREV(&dl->dl_tree, dle);
dle_enqueue_subobj(dl, dle_prev, dle->dle_bpobj.bpo_object, tx);
avl_remove(&dl->dl_tree, dle);
bpobj_close(&dle->dle_bpobj);
kmem_free(dle, sizeof (*dle));
VERIFY0(zap_remove_int(dl->dl_os, dl->dl_object, mintxg, tx));
mutex_exit(&dl->dl_lock);
}
/*
* Remove a deadlist entry and all of its contents by removing the entry from
* the deadlist's avl tree, freeing the entry's bpobj and adjusting the
* deadlist's space accounting accordingly.
*/
void
dsl_deadlist_remove_entry(dsl_deadlist_t *dl, uint64_t mintxg, dmu_tx_t *tx)
{
uint64_t used, comp, uncomp;
dsl_deadlist_entry_t dle_tofind;
dsl_deadlist_entry_t *dle;
objset_t *os = dl->dl_os;
if (dl->dl_oldfmt)
return;
mutex_enter(&dl->dl_lock);
dsl_deadlist_load_tree(dl);
dle_tofind.dle_mintxg = mintxg;
dle = avl_find(&dl->dl_tree, &dle_tofind, NULL);
VERIFY3P(dle, !=, NULL);
avl_remove(&dl->dl_tree, dle);
VERIFY0(zap_remove_int(os, dl->dl_object, mintxg, tx));
VERIFY0(bpobj_space(&dle->dle_bpobj, &used, &comp, &uncomp));
dmu_buf_will_dirty(dl->dl_dbuf, tx);
dl->dl_phys->dl_used -= used;
dl->dl_phys->dl_comp -= comp;
dl->dl_phys->dl_uncomp -= uncomp;
if (dle->dle_bpobj.bpo_object == dmu_objset_pool(os)->dp_empty_bpobj) {
bpobj_decr_empty(os, tx);
} else {
bpobj_free(os, dle->dle_bpobj.bpo_object, tx);
}
bpobj_close(&dle->dle_bpobj);
kmem_free(dle, sizeof (*dle));
mutex_exit(&dl->dl_lock);
}
/*
* Clear out the contents of a deadlist_entry by freeing its bpobj,
* replacing it with an empty bpobj and adjusting the deadlist's
* space accounting
*/
void
dsl_deadlist_clear_entry(dsl_deadlist_entry_t *dle, dsl_deadlist_t *dl,
dmu_tx_t *tx)
{
uint64_t new_obj, used, comp, uncomp;
objset_t *os = dl->dl_os;
mutex_enter(&dl->dl_lock);
VERIFY0(zap_remove_int(os, dl->dl_object, dle->dle_mintxg, tx));
VERIFY0(bpobj_space(&dle->dle_bpobj, &used, &comp, &uncomp));
dmu_buf_will_dirty(dl->dl_dbuf, tx);
dl->dl_phys->dl_used -= used;
dl->dl_phys->dl_comp -= comp;
dl->dl_phys->dl_uncomp -= uncomp;
if (dle->dle_bpobj.bpo_object == dmu_objset_pool(os)->dp_empty_bpobj)
bpobj_decr_empty(os, tx);
else
bpobj_free(os, dle->dle_bpobj.bpo_object, tx);
bpobj_close(&dle->dle_bpobj);
new_obj = bpobj_alloc_empty(os, SPA_OLD_MAXBLOCKSIZE, tx);
VERIFY0(bpobj_open(&dle->dle_bpobj, os, new_obj));
VERIFY0(zap_add_int_key(os, dl->dl_object, dle->dle_mintxg,
new_obj, tx));
ASSERT(bpobj_is_empty(&dle->dle_bpobj));
mutex_exit(&dl->dl_lock);
}
/*
* Return the first entry in deadlist's avl tree
*/
dsl_deadlist_entry_t *
dsl_deadlist_first(dsl_deadlist_t *dl)
{
dsl_deadlist_entry_t *dle;
mutex_enter(&dl->dl_lock);
dsl_deadlist_load_tree(dl);
dle = avl_first(&dl->dl_tree);
mutex_exit(&dl->dl_lock);
return (dle);
}
/*
* Return the last entry in deadlist's avl tree
*/
dsl_deadlist_entry_t *
dsl_deadlist_last(dsl_deadlist_t *dl)
{
dsl_deadlist_entry_t *dle;
mutex_enter(&dl->dl_lock);
dsl_deadlist_load_tree(dl);
dle = avl_last(&dl->dl_tree);
mutex_exit(&dl->dl_lock);
return (dle);
}
/*
* Walk ds's snapshots to regenerate generate ZAP & AVL.
*/
static void
dsl_deadlist_regenerate(objset_t *os, uint64_t dlobj,
uint64_t mrs_obj, dmu_tx_t *tx)
{
dsl_deadlist_t dl = { 0 };
dsl_pool_t *dp = dmu_objset_pool(os);
dsl_deadlist_open(&dl, os, dlobj);
if (dl.dl_oldfmt) {
dsl_deadlist_close(&dl);
return;
}
while (mrs_obj != 0) {
dsl_dataset_t *ds;
VERIFY0(dsl_dataset_hold_obj(dp, mrs_obj, FTAG, &ds));
dsl_deadlist_add_key(&dl,
dsl_dataset_phys(ds)->ds_prev_snap_txg, tx);
mrs_obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
dsl_dataset_rele(ds, FTAG);
}
dsl_deadlist_close(&dl);
}
uint64_t
dsl_deadlist_clone(dsl_deadlist_t *dl, uint64_t maxtxg,
uint64_t mrs_obj, dmu_tx_t *tx)
{
dsl_deadlist_entry_t *dle;
uint64_t newobj;
newobj = dsl_deadlist_alloc(dl->dl_os, tx);
if (dl->dl_oldfmt) {
dsl_deadlist_regenerate(dl->dl_os, newobj, mrs_obj, tx);
return (newobj);
}
mutex_enter(&dl->dl_lock);
dsl_deadlist_load_tree(dl);
for (dle = avl_first(&dl->dl_tree); dle;
dle = AVL_NEXT(&dl->dl_tree, dle)) {
uint64_t obj;
if (dle->dle_mintxg >= maxtxg)
break;
obj = bpobj_alloc_empty(dl->dl_os, SPA_OLD_MAXBLOCKSIZE, tx);
VERIFY0(zap_add_int_key(dl->dl_os, newobj,
dle->dle_mintxg, obj, tx));
}
mutex_exit(&dl->dl_lock);
return (newobj);
}
void
dsl_deadlist_space(dsl_deadlist_t *dl,
uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
{
ASSERT(dsl_deadlist_is_open(dl));
if (dl->dl_oldfmt) {
VERIFY0(bpobj_space(&dl->dl_bpobj,
usedp, compp, uncompp));
return;
}
mutex_enter(&dl->dl_lock);
*usedp = dl->dl_phys->dl_used;
*compp = dl->dl_phys->dl_comp;
*uncompp = dl->dl_phys->dl_uncomp;
mutex_exit(&dl->dl_lock);
}
/*
* return space used in the range (mintxg, maxtxg].
* Includes maxtxg, does not include mintxg.
* mintxg and maxtxg must both be keys in the deadlist (unless maxtxg is
* UINT64_MAX).
*/
void
dsl_deadlist_space_range(dsl_deadlist_t *dl, uint64_t mintxg, uint64_t maxtxg,
uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
{
dsl_deadlist_cache_entry_t *dlce;
dsl_deadlist_cache_entry_t dlce_tofind;
avl_index_t where;
if (dl->dl_oldfmt) {
VERIFY0(bpobj_space_range(&dl->dl_bpobj,
mintxg, maxtxg, usedp, compp, uncompp));
return;
}
*usedp = *compp = *uncompp = 0;
mutex_enter(&dl->dl_lock);
dsl_deadlist_load_cache(dl);
dlce_tofind.dlce_mintxg = mintxg;
dlce = avl_find(&dl->dl_cache, &dlce_tofind, &where);
/*
* If this mintxg doesn't exist, it may be an empty_bpobj which
* is omitted from the sparse tree. Start at the next non-empty
* entry.
*/
if (dlce == NULL)
dlce = avl_nearest(&dl->dl_cache, where, AVL_AFTER);
for (; dlce && dlce->dlce_mintxg < maxtxg;
dlce = AVL_NEXT(&dl->dl_tree, dlce)) {
*usedp += dlce->dlce_bytes;
*compp += dlce->dlce_comp;
*uncompp += dlce->dlce_uncomp;
}
mutex_exit(&dl->dl_lock);
}
static void
dsl_deadlist_insert_bpobj(dsl_deadlist_t *dl, uint64_t obj, uint64_t birth,
dmu_tx_t *tx)
{
dsl_deadlist_entry_t dle_tofind;
dsl_deadlist_entry_t *dle;
avl_index_t where;
uint64_t used, comp, uncomp;
bpobj_t bpo;
ASSERT(MUTEX_HELD(&dl->dl_lock));
VERIFY0(bpobj_open(&bpo, dl->dl_os, obj));
VERIFY0(bpobj_space(&bpo, &used, &comp, &uncomp));
bpobj_close(&bpo);
dsl_deadlist_load_tree(dl);
dmu_buf_will_dirty(dl->dl_dbuf, tx);
dl->dl_phys->dl_used += used;
dl->dl_phys->dl_comp += comp;
dl->dl_phys->dl_uncomp += uncomp;
dle_tofind.dle_mintxg = birth;
dle = avl_find(&dl->dl_tree, &dle_tofind, &where);
if (dle == NULL)
dle = avl_nearest(&dl->dl_tree, where, AVL_BEFORE);
dle_enqueue_subobj(dl, dle, obj, tx);
}
static int
dsl_deadlist_insert_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed,
dmu_tx_t *tx)
{
dsl_deadlist_t *dl = arg;
dsl_deadlist_insert(dl, bp, bp_freed, tx);
return (0);
}
/*
* Merge the deadlist pointed to by 'obj' into dl. obj will be left as
* an empty deadlist.
*/
void
dsl_deadlist_merge(dsl_deadlist_t *dl, uint64_t obj, dmu_tx_t *tx)
{
zap_cursor_t zc;
zap_attribute_t za;
dmu_buf_t *bonus;
dsl_deadlist_phys_t *dlp;
dmu_object_info_t doi;
VERIFY0(dmu_object_info(dl->dl_os, obj, &doi));
if (doi.doi_type == DMU_OT_BPOBJ) {
bpobj_t bpo;
VERIFY0(bpobj_open(&bpo, dl->dl_os, obj));
VERIFY0(bpobj_iterate(&bpo, dsl_deadlist_insert_cb, dl, tx));
bpobj_close(&bpo);
return;
}
mutex_enter(&dl->dl_lock);
for (zap_cursor_init(&zc, dl->dl_os, obj);
zap_cursor_retrieve(&zc, &za) == 0;
zap_cursor_advance(&zc)) {
uint64_t mintxg = zfs_strtonum(za.za_name, NULL);
dsl_deadlist_insert_bpobj(dl, za.za_first_integer, mintxg, tx);
VERIFY0(zap_remove_int(dl->dl_os, obj, mintxg, tx));
}
zap_cursor_fini(&zc);
VERIFY0(dmu_bonus_hold(dl->dl_os, obj, FTAG, &bonus));
dlp = bonus->db_data;
dmu_buf_will_dirty(bonus, tx);
bzero(dlp, sizeof (*dlp));
dmu_buf_rele(bonus, FTAG);
mutex_exit(&dl->dl_lock);
}
/*
* Remove entries on dl that are born > mintxg, and put them on the bpobj.
*/
void
dsl_deadlist_move_bpobj(dsl_deadlist_t *dl, bpobj_t *bpo, uint64_t mintxg,
dmu_tx_t *tx)
{
dsl_deadlist_entry_t dle_tofind;
dsl_deadlist_entry_t *dle;
avl_index_t where;
ASSERT(!dl->dl_oldfmt);
mutex_enter(&dl->dl_lock);
dmu_buf_will_dirty(dl->dl_dbuf, tx);
dsl_deadlist_load_tree(dl);
dle_tofind.dle_mintxg = mintxg;
dle = avl_find(&dl->dl_tree, &dle_tofind, &where);
if (dle == NULL)
dle = avl_nearest(&dl->dl_tree, where, AVL_AFTER);
while (dle) {
uint64_t used, comp, uncomp;
dsl_deadlist_entry_t *dle_next;
bpobj_enqueue_subobj(bpo, dle->dle_bpobj.bpo_object, tx);
VERIFY0(bpobj_space(&dle->dle_bpobj,
&used, &comp, &uncomp));
ASSERT3U(dl->dl_phys->dl_used, >=, used);
ASSERT3U(dl->dl_phys->dl_comp, >=, comp);
ASSERT3U(dl->dl_phys->dl_uncomp, >=, uncomp);
dl->dl_phys->dl_used -= used;
dl->dl_phys->dl_comp -= comp;
dl->dl_phys->dl_uncomp -= uncomp;
VERIFY0(zap_remove_int(dl->dl_os, dl->dl_object,
dle->dle_mintxg, tx));
dle_next = AVL_NEXT(&dl->dl_tree, dle);
avl_remove(&dl->dl_tree, dle);
bpobj_close(&dle->dle_bpobj);
kmem_free(dle, sizeof (*dle));
dle = dle_next;
}
mutex_exit(&dl->dl_lock);
}
typedef struct livelist_entry {
const blkptr_t *le_bp;
avl_node_t le_node;
} livelist_entry_t;
static int
livelist_compare(const void *larg, const void *rarg)
{
const blkptr_t *l = ((livelist_entry_t *)larg)->le_bp;
const blkptr_t *r = ((livelist_entry_t *)rarg)->le_bp;
/* Sort them according to dva[0] */
uint64_t l_dva0_vdev = DVA_GET_VDEV(&l->blk_dva[0]);
uint64_t r_dva0_vdev = DVA_GET_VDEV(&r->blk_dva[0]);
if (l_dva0_vdev != r_dva0_vdev)
return (TREE_CMP(l_dva0_vdev, r_dva0_vdev));
/* if vdevs are equal, sort by offsets. */
uint64_t l_dva0_offset = DVA_GET_OFFSET(&l->blk_dva[0]);
uint64_t r_dva0_offset = DVA_GET_OFFSET(&r->blk_dva[0]);
if (l_dva0_offset == r_dva0_offset)
ASSERT3U(l->blk_birth, ==, r->blk_birth);
return (TREE_CMP(l_dva0_offset, r_dva0_offset));
}
struct livelist_iter_arg {
avl_tree_t *avl;
bplist_t *to_free;
zthr_t *t;
};
/*
* Expects an AVL tree which is incrementally filled will FREE blkptrs
* and used to match up ALLOC/FREE pairs. ALLOC'd blkptrs without a
* corresponding FREE are stored in the supplied bplist.
*/
static int
dsl_livelist_iterate(void *arg, const blkptr_t *bp, boolean_t bp_freed,
dmu_tx_t *tx)
{
struct livelist_iter_arg *lia = arg;
avl_tree_t *avl = lia->avl;
bplist_t *to_free = lia->to_free;
zthr_t *t = lia->t;
ASSERT(tx == NULL);
if ((t != NULL) && (zthr_has_waiters(t) || zthr_iscancelled(t)))
return (SET_ERROR(EINTR));
if (bp_freed) {
livelist_entry_t *node = kmem_alloc(sizeof (livelist_entry_t),
KM_SLEEP);
blkptr_t *temp_bp = kmem_alloc(sizeof (blkptr_t), KM_SLEEP);
*temp_bp = *bp;
node->le_bp = temp_bp;
avl_add(avl, node);
} else {
livelist_entry_t node;
node.le_bp = bp;
livelist_entry_t *found = avl_find(avl, &node, NULL);
if (found != NULL) {
avl_remove(avl, found);
kmem_free((blkptr_t *)found->le_bp, sizeof (blkptr_t));
kmem_free(found, sizeof (livelist_entry_t));
} else {
bplist_append(to_free, bp);
}
}
return (0);
}
/*
* Accepts a bpobj and a bplist. Will insert into the bplist the blkptrs
* which have an ALLOC entry but no matching FREE
*/
int
dsl_process_sub_livelist(bpobj_t *bpobj, bplist_t *to_free, zthr_t *t,
uint64_t *size)
{
avl_tree_t avl;
avl_create(&avl, livelist_compare, sizeof (livelist_entry_t),
offsetof(livelist_entry_t, le_node));
/* process the sublist */
struct livelist_iter_arg arg = {
.avl = &avl,
.to_free = to_free,
.t = t
};
int err = bpobj_iterate_nofree(bpobj, dsl_livelist_iterate, &arg, size);
avl_destroy(&avl);
return (err);
}
/* BEGIN CSTYLED */
ZFS_MODULE_PARAM(zfs_livelist, zfs_livelist_, max_entries, ULONG, ZMOD_RW,
"Size to start the next sub-livelist in a livelist");
ZFS_MODULE_PARAM(zfs_livelist, zfs_livelist_, min_percent_shared, INT, ZMOD_RW,
"Threshold at which livelist is disabled");
/* END CSTYLED */
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