mirror_zfs/include/sys/spa_impl.h
Serapheim Dimitropoulos 93e28d661e Log Spacemap Project
= Motivation

At Delphix we've seen a lot of customer systems where fragmentation
is over 75% and random writes take a performance hit because a lot
of time is spend on I/Os that update on-disk space accounting metadata.
Specifically, we seen cases where 20% to 40% of sync time is spend
after sync pass 1 and ~30% of the I/Os on the system is spent updating
spacemaps.

The problem is that these pools have existed long enough that we've
touched almost every metaslab at least once, and random writes
scatter frees across all metaslabs every TXG, thus appending to
their spacemaps and resulting in many I/Os. To give an example,
assuming that every VDEV has 200 metaslabs and our writes fit within
a single spacemap block (generally 4K) we have 200 I/Os. Then if we
assume 2 levels of indirection, we need 400 additional I/Os and
since we are talking about metadata for which we keep 2 extra copies
for redundancy we need to triple that number, leading to a total of
1800 I/Os per VDEV every TXG.

We could try and decrease the number of metaslabs so we have less
I/Os per TXG but then each metaslab would cover a wider range on
disk and thus would take more time to be loaded in memory from disk.
In addition, after it's loaded, it's range tree would consume more
memory.

Another idea would be to just increase the spacemap block size
which would allow us to fit more entries within an I/O block
resulting in fewer I/Os per metaslab and a speedup in loading time.
The problem is still that we don't deal with the number of I/Os
going up as the number of metaslabs is increasing and the fact
is that we generally write a lot to a few metaslabs and a little
to the rest of them. Thus, just increasing the block size would
actually waste bandwidth because we won't be utilizing our bigger
block size.

= About this patch

This patch introduces the Log Spacemap project which provides the
solution to the above problem while taking into account all the
aforementioned tradeoffs. The details on how it achieves that can
be found in the references sections below and in the code (see
Big Theory Statement in spa_log_spacemap.c).

Even though the change is fairly constraint within the metaslab
and lower-level SPA codepaths, there is a side-change that is
user-facing. The change is that VDEV IDs from VDEV holes will no
longer be reused. To give some background and reasoning for this,
when a log device is removed and its VDEV structure was replaced
with a hole (or was compacted; if at the end of the vdev array),
its vdev_id could be reused by devices added after that. Now
with the pool-wide space maps recording the vdev ID, this behavior
can cause problems (e.g. is this entry referring to a segment in
the new vdev or the removed log?). Thus, to simplify things the
ID reuse behavior is gone and now vdev IDs for top-level vdevs
are truly unique within a pool.

= Testing

The illumos implementation of this feature has been used internally
for a year and has been in production for ~6 months. For this patch
specifically there don't seem to be any regressions introduced to
ZTS and I have been running zloop for a week without any related
problems.

= Performance Analysis (Linux Specific)

All performance results and analysis for illumos can be found in
the links of the references. Redoing the same experiments in Linux
gave similar results. Below are the specifics of the Linux run.

After the pool reached stable state the percentage of the time
spent in pass 1 per TXG was 64% on average for the stock bits
while the log spacemap bits stayed at 95% during the experiment
(graph: sdimitro.github.io/img/linux-lsm/PercOfSyncInPassOne.png).

Sync times per TXG were 37.6 seconds on average for the stock
bits and 22.7 seconds for the log spacemap bits (related graph:
sdimitro.github.io/img/linux-lsm/SyncTimePerTXG.png). As a result
the log spacemap bits were able to push more TXGs, which is also
the reason why all graphs quantified per TXG have more entries for
the log spacemap bits.

Another interesting aspect in terms of txg syncs is that the stock
bits had 22% of their TXGs reach sync pass 7, 55% reach sync pass 8,
and 20% reach 9. The log space map bits reached sync pass 4 in 79%
of their TXGs, sync pass 7 in 19%, and sync pass 8 at 1%. This
emphasizes the fact that not only we spend less time on metadata
but we also iterate less times to convergence in spa_sync() dirtying
objects.
[related graphs:
stock- sdimitro.github.io/img/linux-lsm/NumberOfPassesPerTXGStock.png
lsm- sdimitro.github.io/img/linux-lsm/NumberOfPassesPerTXGLSM.png]

Finally, the improvement in IOPs that the userland gains from the
change is approximately 40%. There is a consistent win in IOPS as
you can see from the graphs below but the absolute amount of
improvement that the log spacemap gives varies within each minute
interval.
sdimitro.github.io/img/linux-lsm/StockVsLog3Days.png
sdimitro.github.io/img/linux-lsm/StockVsLog10Hours.png

= Porting to Other Platforms

For people that want to port this commit to other platforms below
is a list of ZoL commits that this patch depends on:

Make zdb results for checkpoint tests consistent
db587941c5

Update vdev_is_spacemap_addressable() for new spacemap encoding
419ba59145

Simplify spa_sync by breaking it up to smaller functions
8dc2197b7b

Factor metaslab_load_wait() in metaslab_load()
b194fab0fb

Rename range_tree_verify to range_tree_verify_not_present
df72b8bebe

Change target size of metaslabs from 256GB to 16GB
c853f382db

zdb -L should skip leak detection altogether
21e7cf5da8

vs_alloc can underflow in L2ARC vdevs
7558997d2f

Simplify log vdev removal code
6c926f426a

Get rid of space_map_update() for ms_synced_length
425d3237ee

Introduce auxiliary metaslab histograms
928e8ad47d

Error path in metaslab_load_impl() forgets to drop ms_sync_lock
8eef997679

= References

Background, Motivation, and Internals of the Feature
- OpenZFS 2017 Presentation:
youtu.be/jj2IxRkl5bQ
- Slides:
slideshare.net/SerapheimNikolaosDim/zfs-log-spacemaps-project

Flushing Algorithm Internals & Performance Results
(Illumos Specific)
- Blogpost:
sdimitro.github.io/post/zfs-lsm-flushing/
- OpenZFS 2018 Presentation:
youtu.be/x6D2dHRjkxw
- Slides:
slideshare.net/SerapheimNikolaosDim/zfs-log-spacemap-flushing-algorithm

Upstream Delphix Issues:
DLPX-51539, DLPX-59659, DLPX-57783, DLPX-61438, DLPX-41227, DLPX-59320
DLPX-63385

Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8442
2019-07-16 10:11:49 -07:00

436 lines
17 KiB
C

/*
* 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
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* 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]
*
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*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2011, 2019 by Delphix. All rights reserved.
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
* Copyright 2013 Saso Kiselkov. All rights reserved.
* Copyright (c) 2016 Actifio, Inc. All rights reserved.
* Copyright (c) 2017 Datto Inc.
* Copyright (c) 2017, Intel Corporation.
*/
#ifndef _SYS_SPA_IMPL_H
#define _SYS_SPA_IMPL_H
#include <sys/spa.h>
#include <sys/spa_checkpoint.h>
#include <sys/spa_log_spacemap.h>
#include <sys/vdev.h>
#include <sys/vdev_removal.h>
#include <sys/metaslab.h>
#include <sys/dmu.h>
#include <sys/dsl_pool.h>
#include <sys/uberblock_impl.h>
#include <sys/zfs_context.h>
#include <sys/avl.h>
#include <sys/refcount.h>
#include <sys/bplist.h>
#include <sys/bpobj.h>
#include <sys/dsl_crypt.h>
#include <sys/zfeature.h>
#include <sys/zthr.h>
#include <zfeature_common.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef struct spa_error_entry {
zbookmark_phys_t se_bookmark;
char *se_name;
avl_node_t se_avl;
} spa_error_entry_t;
typedef struct spa_history_phys {
uint64_t sh_pool_create_len; /* ending offset of zpool create */
uint64_t sh_phys_max_off; /* physical EOF */
uint64_t sh_bof; /* logical BOF */
uint64_t sh_eof; /* logical EOF */
uint64_t sh_records_lost; /* num of records overwritten */
} spa_history_phys_t;
/*
* All members must be uint64_t, for byteswap purposes.
*/
typedef struct spa_removing_phys {
uint64_t sr_state; /* dsl_scan_state_t */
/*
* The vdev ID that we most recently attempted to remove,
* or -1 if no removal has been attempted.
*/
uint64_t sr_removing_vdev;
/*
* The vdev ID that we most recently successfully removed,
* or -1 if no devices have been removed.
*/
uint64_t sr_prev_indirect_vdev;
uint64_t sr_start_time;
uint64_t sr_end_time;
/*
* Note that we can not use the space map's or indirect mapping's
* accounting as a substitute for these values, because we need to
* count frees of not-yet-copied data as though it did the copy.
* Otherwise, we could get into a situation where copied > to_copy,
* or we complete before copied == to_copy.
*/
uint64_t sr_to_copy; /* bytes that need to be copied */
uint64_t sr_copied; /* bytes that have been copied or freed */
} spa_removing_phys_t;
/*
* This struct is stored as an entry in the DMU_POOL_DIRECTORY_OBJECT
* (with key DMU_POOL_CONDENSING_INDIRECT). It is present if a condense
* of an indirect vdev's mapping object is in progress.
*/
typedef struct spa_condensing_indirect_phys {
/*
* The vdev ID of the indirect vdev whose indirect mapping is
* being condensed.
*/
uint64_t scip_vdev;
/*
* The vdev's old obsolete spacemap. This spacemap's contents are
* being integrated into the new mapping.
*/
uint64_t scip_prev_obsolete_sm_object;
/*
* The new mapping object that is being created.
*/
uint64_t scip_next_mapping_object;
} spa_condensing_indirect_phys_t;
struct spa_aux_vdev {
uint64_t sav_object; /* MOS object for device list */
nvlist_t *sav_config; /* cached device config */
vdev_t **sav_vdevs; /* devices */
int sav_count; /* number devices */
boolean_t sav_sync; /* sync the device list */
nvlist_t **sav_pending; /* pending device additions */
uint_t sav_npending; /* # pending devices */
};
typedef struct spa_config_lock {
kmutex_t scl_lock;
kthread_t *scl_writer;
int scl_write_wanted;
kcondvar_t scl_cv;
zfs_refcount_t scl_count;
} spa_config_lock_t;
typedef struct spa_config_dirent {
list_node_t scd_link;
char *scd_path;
} spa_config_dirent_t;
typedef enum zio_taskq_type {
ZIO_TASKQ_ISSUE = 0,
ZIO_TASKQ_ISSUE_HIGH,
ZIO_TASKQ_INTERRUPT,
ZIO_TASKQ_INTERRUPT_HIGH,
ZIO_TASKQ_TYPES
} zio_taskq_type_t;
/*
* State machine for the zpool-poolname process. The states transitions
* are done as follows:
*
* From To Routine
* PROC_NONE -> PROC_CREATED spa_activate()
* PROC_CREATED -> PROC_ACTIVE spa_thread()
* PROC_ACTIVE -> PROC_DEACTIVATE spa_deactivate()
* PROC_DEACTIVATE -> PROC_GONE spa_thread()
* PROC_GONE -> PROC_NONE spa_deactivate()
*/
typedef enum spa_proc_state {
SPA_PROC_NONE, /* spa_proc = &p0, no process created */
SPA_PROC_CREATED, /* spa_activate() has proc, is waiting */
SPA_PROC_ACTIVE, /* taskqs created, spa_proc set */
SPA_PROC_DEACTIVATE, /* spa_deactivate() requests process exit */
SPA_PROC_GONE /* spa_thread() is exiting, spa_proc = &p0 */
} spa_proc_state_t;
typedef struct spa_taskqs {
uint_t stqs_count;
taskq_t **stqs_taskq;
} spa_taskqs_t;
typedef enum spa_all_vdev_zap_action {
AVZ_ACTION_NONE = 0,
AVZ_ACTION_DESTROY, /* Destroy all per-vdev ZAPs and the AVZ. */
AVZ_ACTION_REBUILD, /* Populate the new AVZ, see spa_avz_rebuild */
AVZ_ACTION_INITIALIZE
} spa_avz_action_t;
typedef enum spa_config_source {
SPA_CONFIG_SRC_NONE = 0,
SPA_CONFIG_SRC_SCAN, /* scan of path (default: /dev/dsk) */
SPA_CONFIG_SRC_CACHEFILE, /* any cachefile */
SPA_CONFIG_SRC_TRYIMPORT, /* returned from call to tryimport */
SPA_CONFIG_SRC_SPLIT, /* new pool in a pool split */
SPA_CONFIG_SRC_MOS /* MOS, but not always from right txg */
} spa_config_source_t;
struct spa {
/*
* Fields protected by spa_namespace_lock.
*/
char spa_name[ZFS_MAX_DATASET_NAME_LEN]; /* pool name */
char *spa_comment; /* comment */
avl_node_t spa_avl; /* node in spa_namespace_avl */
nvlist_t *spa_config; /* last synced config */
nvlist_t *spa_config_syncing; /* currently syncing config */
nvlist_t *spa_config_splitting; /* config for splitting */
nvlist_t *spa_load_info; /* info and errors from load */
uint64_t spa_config_txg; /* txg of last config change */
int spa_sync_pass; /* iterate-to-convergence */
pool_state_t spa_state; /* pool state */
int spa_inject_ref; /* injection references */
uint8_t spa_sync_on; /* sync threads are running */
spa_load_state_t spa_load_state; /* current load operation */
boolean_t spa_indirect_vdevs_loaded; /* mappings loaded? */
boolean_t spa_trust_config; /* do we trust vdev tree? */
spa_config_source_t spa_config_source; /* where config comes from? */
uint64_t spa_import_flags; /* import specific flags */
spa_taskqs_t spa_zio_taskq[ZIO_TYPES][ZIO_TASKQ_TYPES];
dsl_pool_t *spa_dsl_pool;
boolean_t spa_is_initializing; /* true while opening pool */
metaslab_class_t *spa_normal_class; /* normal data class */
metaslab_class_t *spa_log_class; /* intent log data class */
metaslab_class_t *spa_special_class; /* special allocation class */
metaslab_class_t *spa_dedup_class; /* dedup allocation class */
uint64_t spa_first_txg; /* first txg after spa_open() */
uint64_t spa_final_txg; /* txg of export/destroy */
uint64_t spa_freeze_txg; /* freeze pool at this txg */
uint64_t spa_load_max_txg; /* best initial ub_txg */
uint64_t spa_claim_max_txg; /* highest claimed birth txg */
inode_timespec_t spa_loaded_ts; /* 1st successful open time */
objset_t *spa_meta_objset; /* copy of dp->dp_meta_objset */
kmutex_t spa_evicting_os_lock; /* Evicting objset list lock */
list_t spa_evicting_os_list; /* Objsets being evicted. */
kcondvar_t spa_evicting_os_cv; /* Objset Eviction Completion */
txg_list_t spa_vdev_txg_list; /* per-txg dirty vdev list */
vdev_t *spa_root_vdev; /* top-level vdev container */
int spa_min_ashift; /* of vdevs in normal class */
int spa_max_ashift; /* of vdevs in normal class */
uint64_t spa_config_guid; /* config pool guid */
uint64_t spa_load_guid; /* spa_load initialized guid */
uint64_t spa_last_synced_guid; /* last synced guid */
list_t spa_config_dirty_list; /* vdevs with dirty config */
list_t spa_state_dirty_list; /* vdevs with dirty state */
/*
* spa_alloc_locks and spa_alloc_trees are arrays, whose lengths are
* stored in spa_alloc_count. There is one tree and one lock for each
* allocator, to help improve allocation performance in write-heavy
* workloads.
*/
kmutex_t *spa_alloc_locks;
avl_tree_t *spa_alloc_trees;
int spa_alloc_count;
spa_aux_vdev_t spa_spares; /* hot spares */
spa_aux_vdev_t spa_l2cache; /* L2ARC cache devices */
nvlist_t *spa_label_features; /* Features for reading MOS */
uint64_t spa_config_object; /* MOS object for pool config */
uint64_t spa_config_generation; /* config generation number */
uint64_t spa_syncing_txg; /* txg currently syncing */
bpobj_t spa_deferred_bpobj; /* deferred-free bplist */
bplist_t spa_free_bplist[TXG_SIZE]; /* bplist of stuff to free */
zio_cksum_salt_t spa_cksum_salt; /* secret salt for cksum */
/* checksum context templates */
kmutex_t spa_cksum_tmpls_lock;
void *spa_cksum_tmpls[ZIO_CHECKSUM_FUNCTIONS];
uberblock_t spa_ubsync; /* last synced uberblock */
uberblock_t spa_uberblock; /* current uberblock */
boolean_t spa_extreme_rewind; /* rewind past deferred frees */
kmutex_t spa_scrub_lock; /* resilver/scrub lock */
uint64_t spa_scrub_inflight; /* in-flight scrub bytes */
uint64_t spa_load_verify_ios; /* in-flight verification IOs */
kcondvar_t spa_scrub_io_cv; /* scrub I/O completion */
uint8_t spa_scrub_active; /* active or suspended? */
uint8_t spa_scrub_type; /* type of scrub we're doing */
uint8_t spa_scrub_finished; /* indicator to rotate logs */
uint8_t spa_scrub_started; /* started since last boot */
uint8_t spa_scrub_reopen; /* scrub doing vdev_reopen */
uint64_t spa_scan_pass_start; /* start time per pass/reboot */
uint64_t spa_scan_pass_scrub_pause; /* scrub pause time */
uint64_t spa_scan_pass_scrub_spent_paused; /* total paused */
uint64_t spa_scan_pass_exam; /* examined bytes per pass */
uint64_t spa_scan_pass_issued; /* issued bytes per pass */
/*
* We are in the middle of a resilver, and another resilver
* is needed once this one completes. This is set iff any
* vdev_resilver_deferred is set.
*/
boolean_t spa_resilver_deferred;
kmutex_t spa_async_lock; /* protect async state */
kthread_t *spa_async_thread; /* thread doing async task */
int spa_async_suspended; /* async tasks suspended */
kcondvar_t spa_async_cv; /* wait for thread_exit() */
uint16_t spa_async_tasks; /* async task mask */
uint64_t spa_missing_tvds; /* unopenable tvds on load */
uint64_t spa_missing_tvds_allowed; /* allow loading spa? */
spa_removing_phys_t spa_removing_phys;
spa_vdev_removal_t *spa_vdev_removal;
spa_condensing_indirect_phys_t spa_condensing_indirect_phys;
spa_condensing_indirect_t *spa_condensing_indirect;
zthr_t *spa_condense_zthr; /* zthr doing condense. */
uint64_t spa_checkpoint_txg; /* the txg of the checkpoint */
spa_checkpoint_info_t spa_checkpoint_info; /* checkpoint accounting */
zthr_t *spa_checkpoint_discard_zthr;
space_map_t *spa_syncing_log_sm; /* current log space map */
avl_tree_t spa_sm_logs_by_txg;
kmutex_t spa_flushed_ms_lock; /* for metaslabs_by_flushed */
avl_tree_t spa_metaslabs_by_flushed;
spa_unflushed_stats_t spa_unflushed_stats;
list_t spa_log_summary;
uint64_t spa_log_flushall_txg;
char *spa_root; /* alternate root directory */
uint64_t spa_ena; /* spa-wide ereport ENA */
int spa_last_open_failed; /* error if last open failed */
uint64_t spa_last_ubsync_txg; /* "best" uberblock txg */
uint64_t spa_last_ubsync_txg_ts; /* timestamp from that ub */
uint64_t spa_load_txg; /* ub txg that loaded */
uint64_t spa_load_txg_ts; /* timestamp from that ub */
uint64_t spa_load_meta_errors; /* verify metadata err count */
uint64_t spa_load_data_errors; /* verify data err count */
uint64_t spa_verify_min_txg; /* start txg of verify scrub */
kmutex_t spa_errlog_lock; /* error log lock */
uint64_t spa_errlog_last; /* last error log object */
uint64_t spa_errlog_scrub; /* scrub error log object */
kmutex_t spa_errlist_lock; /* error list/ereport lock */
avl_tree_t spa_errlist_last; /* last error list */
avl_tree_t spa_errlist_scrub; /* scrub error list */
uint64_t spa_deflate; /* should we deflate? */
uint64_t spa_history; /* history object */
kmutex_t spa_history_lock; /* history lock */
vdev_t *spa_pending_vdev; /* pending vdev additions */
kmutex_t spa_props_lock; /* property lock */
uint64_t spa_pool_props_object; /* object for properties */
uint64_t spa_bootfs; /* default boot filesystem */
uint64_t spa_failmode; /* failure mode for the pool */
uint64_t spa_deadman_failmode; /* failure mode for deadman */
uint64_t spa_delegation; /* delegation on/off */
list_t spa_config_list; /* previous cache file(s) */
/* per-CPU array of root of async I/O: */
zio_t **spa_async_zio_root;
zio_t *spa_suspend_zio_root; /* root of all suspended I/O */
zio_t *spa_txg_zio[TXG_SIZE]; /* spa_sync() waits for this */
kmutex_t spa_suspend_lock; /* protects suspend_zio_root */
kcondvar_t spa_suspend_cv; /* notification of resume */
zio_suspend_reason_t spa_suspended; /* pool is suspended */
uint8_t spa_claiming; /* pool is doing zil_claim() */
boolean_t spa_is_root; /* pool is root */
int spa_minref; /* num refs when first opened */
int spa_mode; /* FREAD | FWRITE */
spa_log_state_t spa_log_state; /* log state */
uint64_t spa_autoexpand; /* lun expansion on/off */
ddt_t *spa_ddt[ZIO_CHECKSUM_FUNCTIONS]; /* in-core DDTs */
uint64_t spa_ddt_stat_object; /* DDT statistics */
uint64_t spa_dedup_dspace; /* Cache get_dedup_dspace() */
uint64_t spa_dedup_checksum; /* default dedup checksum */
uint64_t spa_dspace; /* dspace in normal class */
kmutex_t spa_vdev_top_lock; /* dueling offline/remove */
kmutex_t spa_proc_lock; /* protects spa_proc* */
kcondvar_t spa_proc_cv; /* spa_proc_state transitions */
spa_proc_state_t spa_proc_state; /* see definition */
proc_t *spa_proc; /* "zpool-poolname" process */
uint64_t spa_did; /* if procp != p0, did of t1 */
boolean_t spa_autoreplace; /* autoreplace set in open */
int spa_vdev_locks; /* locks grabbed */
uint64_t spa_creation_version; /* version at pool creation */
uint64_t spa_prev_software_version; /* See ub_software_version */
uint64_t spa_feat_for_write_obj; /* required to write to pool */
uint64_t spa_feat_for_read_obj; /* required to read from pool */
uint64_t spa_feat_desc_obj; /* Feature descriptions */
uint64_t spa_feat_enabled_txg_obj; /* Feature enabled txg */
kmutex_t spa_feat_stats_lock; /* protects spa_feat_stats */
nvlist_t *spa_feat_stats; /* Cache of enabled features */
/* cache feature refcounts */
uint64_t spa_feat_refcount_cache[SPA_FEATURES];
taskqid_t spa_deadman_tqid; /* Task id */
uint64_t spa_deadman_calls; /* number of deadman calls */
hrtime_t spa_sync_starttime; /* starting time of spa_sync */
uint64_t spa_deadman_synctime; /* deadman sync expiration */
uint64_t spa_deadman_ziotime; /* deadman zio expiration */
uint64_t spa_all_vdev_zaps; /* ZAP of per-vd ZAP obj #s */
spa_avz_action_t spa_avz_action; /* destroy/rebuild AVZ? */
uint64_t spa_autotrim; /* automatic background trim? */
uint64_t spa_errata; /* errata issues detected */
spa_stats_t spa_stats; /* assorted spa statistics */
spa_keystore_t spa_keystore; /* loaded crypto keys */
/* arc_memory_throttle() parameters during low memory condition */
uint64_t spa_lowmem_page_load; /* memory load during txg */
uint64_t spa_lowmem_last_txg; /* txg window start */
hrtime_t spa_ccw_fail_time; /* Conf cache write fail time */
taskq_t *spa_zvol_taskq; /* Taskq for minor management */
taskq_t *spa_prefetch_taskq; /* Taskq for prefetch threads */
uint64_t spa_multihost; /* multihost aware (mmp) */
mmp_thread_t spa_mmp; /* multihost mmp thread */
list_t spa_leaf_list; /* list of leaf vdevs */
uint64_t spa_leaf_list_gen; /* track leaf_list changes */
/*
* spa_refcount & spa_config_lock must be the last elements
* because zfs_refcount_t changes size based on compilation options.
* In order for the MDB module to function correctly, the other
* fields must remain in the same location.
*/
spa_config_lock_t spa_config_lock[SCL_LOCKS]; /* config changes */
zfs_refcount_t spa_refcount; /* number of opens */
taskq_t *spa_upgrade_taskq; /* taskq for upgrade jobs */
};
extern char *spa_config_path;
extern void spa_taskq_dispatch_ent(spa_t *spa, zio_type_t t, zio_taskq_type_t q,
task_func_t *func, void *arg, uint_t flags, taskq_ent_t *ent);
extern void spa_taskq_dispatch_sync(spa_t *, zio_type_t t, zio_taskq_type_t q,
task_func_t *func, void *arg, uint_t flags);
extern void spa_load_spares(spa_t *spa);
extern void spa_load_l2cache(spa_t *spa);
extern sysevent_t *spa_event_create(spa_t *spa, vdev_t *vd, nvlist_t *hist_nvl,
const char *name);
extern void spa_event_post(sysevent_t *ev);
#ifdef __cplusplus
}
#endif
#endif /* _SYS_SPA_IMPL_H */