514 lines
20 KiB
C
514 lines
20 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
|
||
|
|
* 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 2009 Sun Microsystems, Inc. All rights reserved.
|
||
|
|
* Use is subject to license terms.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Copyright (c) 2011, 2018 by Delphix. All rights reserved.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef _SYS_METASLAB_IMPL_H
|
||
|
|
#define _SYS_METASLAB_IMPL_H
|
||
|
|
|
||
|
|
#include <sys/metaslab.h>
|
||
|
|
#include <sys/space_map.h>
|
||
|
|
#include <sys/range_tree.h>
|
||
|
|
#include <sys/vdev.h>
|
||
|
|
#include <sys/txg.h>
|
||
|
|
#include <sys/avl.h>
|
||
|
|
|
||
|
|
#ifdef __cplusplus
|
||
|
|
extern "C" {
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Metaslab allocation tracing record.
|
||
|
|
*/
|
||
|
|
typedef struct metaslab_alloc_trace {
|
||
|
|
list_node_t mat_list_node;
|
||
|
|
metaslab_group_t *mat_mg;
|
||
|
|
metaslab_t *mat_msp;
|
||
|
|
uint64_t mat_size;
|
||
|
|
uint64_t mat_weight;
|
||
|
|
uint32_t mat_dva_id;
|
||
|
|
uint64_t mat_offset;
|
||
|
|
int mat_allocator;
|
||
|
|
} metaslab_alloc_trace_t;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Used by the metaslab allocation tracing facility to indicate
|
||
|
|
* error conditions. These errors are stored to the offset member
|
||
|
|
* of the metaslab_alloc_trace_t record and displayed by mdb.
|
||
|
|
*/
|
||
|
|
typedef enum trace_alloc_type {
|
||
|
|
TRACE_ALLOC_FAILURE = -1ULL,
|
||
|
|
TRACE_TOO_SMALL = -2ULL,
|
||
|
|
TRACE_FORCE_GANG = -3ULL,
|
||
|
|
TRACE_NOT_ALLOCATABLE = -4ULL,
|
||
|
|
TRACE_GROUP_FAILURE = -5ULL,
|
||
|
|
TRACE_ENOSPC = -6ULL,
|
||
|
|
TRACE_CONDENSING = -7ULL,
|
||
|
|
TRACE_VDEV_ERROR = -8ULL,
|
||
|
|
TRACE_DISABLED = -9ULL,
|
||
|
|
} trace_alloc_type_t;
|
||
|
|
|
||
|
|
#define METASLAB_WEIGHT_PRIMARY (1ULL << 63)
|
||
|
|
#define METASLAB_WEIGHT_SECONDARY (1ULL << 62)
|
||
|
|
#define METASLAB_WEIGHT_CLAIM (1ULL << 61)
|
||
|
|
#define METASLAB_WEIGHT_TYPE (1ULL << 60)
|
||
|
|
#define METASLAB_ACTIVE_MASK \
|
||
|
|
(METASLAB_WEIGHT_PRIMARY | METASLAB_WEIGHT_SECONDARY | \
|
||
|
|
METASLAB_WEIGHT_CLAIM)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The metaslab weight is used to encode the amount of free space in a
|
||
|
|
* metaslab, such that the "best" metaslab appears first when sorting the
|
||
|
|
* metaslabs by weight. The weight (and therefore the "best" metaslab) can
|
||
|
|
* be determined in two different ways: by computing a weighted sum of all
|
||
|
|
* the free space in the metaslab (a space based weight) or by counting only
|
||
|
|
* the free segments of the largest size (a segment based weight). We prefer
|
||
|
|
* the segment based weight because it reflects how the free space is
|
||
|
|
* comprised, but we cannot always use it -- legacy pools do not have the
|
||
|
|
* space map histogram information necessary to determine the largest
|
||
|
|
* contiguous regions. Pools that have the space map histogram determine
|
||
|
|
* the segment weight by looking at each bucket in the histogram and
|
||
|
|
* determining the free space whose size in bytes is in the range:
|
||
|
|
* [2^i, 2^(i+1))
|
||
|
|
* We then encode the largest index, i, that contains regions into the
|
||
|
|
* segment-weighted value.
|
||
|
|
*
|
||
|
|
* Space-based weight:
|
||
|
|
*
|
||
|
|
* 64 56 48 40 32 24 16 8 0
|
||
|
|
* +-------+-------+-------+-------+-------+-------+-------+-------+
|
||
|
|
* |PSC1| weighted-free space |
|
||
|
|
* +-------+-------+-------+-------+-------+-------+-------+-------+
|
||
|
|
*
|
||
|
|
* PS - indicates primary and secondary activation
|
||
|
|
* C - indicates activation for claimed block zio
|
||
|
|
* space - the fragmentation-weighted space
|
||
|
|
*
|
||
|
|
* Segment-based weight:
|
||
|
|
*
|
||
|
|
* 64 56 48 40 32 24 16 8 0
|
||
|
|
* +-------+-------+-------+-------+-------+-------+-------+-------+
|
||
|
|
* |PSC0| idx| count of segments in region |
|
||
|
|
* +-------+-------+-------+-------+-------+-------+-------+-------+
|
||
|
|
*
|
||
|
|
* PS - indicates primary and secondary activation
|
||
|
|
* C - indicates activation for claimed block zio
|
||
|
|
* idx - index for the highest bucket in the histogram
|
||
|
|
* count - number of segments in the specified bucket
|
||
|
|
*/
|
||
|
|
#define WEIGHT_GET_ACTIVE(weight) BF64_GET((weight), 61, 3)
|
||
|
|
#define WEIGHT_SET_ACTIVE(weight, x) BF64_SET((weight), 61, 3, x)
|
||
|
|
|
||
|
|
#define WEIGHT_IS_SPACEBASED(weight) \
|
||
|
|
((weight) == 0 || BF64_GET((weight), 60, 1))
|
||
|
|
#define WEIGHT_SET_SPACEBASED(weight) BF64_SET((weight), 60, 1, 1)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* These macros are only applicable to segment-based weighting.
|
||
|
|
*/
|
||
|
|
#define WEIGHT_GET_INDEX(weight) BF64_GET((weight), 54, 6)
|
||
|
|
#define WEIGHT_SET_INDEX(weight, x) BF64_SET((weight), 54, 6, x)
|
||
|
|
#define WEIGHT_GET_COUNT(weight) BF64_GET((weight), 0, 54)
|
||
|
|
#define WEIGHT_SET_COUNT(weight, x) BF64_SET((weight), 0, 54, x)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* A metaslab class encompasses a category of allocatable top-level vdevs.
|
||
|
|
* Each top-level vdev is associated with a metaslab group which defines
|
||
|
|
* the allocatable region for that vdev. Examples of these categories include
|
||
|
|
* "normal" for data block allocations (i.e. main pool allocations) or "log"
|
||
|
|
* for allocations designated for intent log devices (i.e. slog devices).
|
||
|
|
* When a block allocation is requested from the SPA it is associated with a
|
||
|
|
* metaslab_class_t, and only top-level vdevs (i.e. metaslab groups) belonging
|
||
|
|
* to the class can be used to satisfy that request. Allocations are done
|
||
|
|
* by traversing the metaslab groups that are linked off of the mc_rotor field.
|
||
|
|
* This rotor points to the next metaslab group where allocations will be
|
||
|
|
* attempted. Allocating a block is a 3 step process -- select the metaslab
|
||
|
|
* group, select the metaslab, and then allocate the block. The metaslab
|
||
|
|
* class defines the low-level block allocator that will be used as the
|
||
|
|
* final step in allocation. These allocators are pluggable allowing each class
|
||
|
|
* to use a block allocator that best suits that class.
|
||
|
|
*/
|
||
|
|
struct metaslab_class {
|
||
|
|
kmutex_t mc_lock;
|
||
|
|
spa_t *mc_spa;
|
||
|
|
metaslab_group_t *mc_rotor;
|
||
|
|
metaslab_ops_t *mc_ops;
|
||
|
|
uint64_t mc_aliquot;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Track the number of metaslab groups that have been initialized
|
||
|
|
* and can accept allocations. An initialized metaslab group is
|
||
|
|
* one has been completely added to the config (i.e. we have
|
||
|
|
* updated the MOS config and the space has been added to the pool).
|
||
|
|
*/
|
||
|
|
uint64_t mc_groups;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Toggle to enable/disable the allocation throttle.
|
||
|
|
*/
|
||
|
|
boolean_t mc_alloc_throttle_enabled;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The allocation throttle works on a reservation system. Whenever
|
||
|
|
* an asynchronous zio wants to perform an allocation it must
|
||
|
|
* first reserve the number of blocks that it wants to allocate.
|
||
|
|
* If there aren't sufficient slots available for the pending zio
|
||
|
|
* then that I/O is throttled until more slots free up. The current
|
||
|
|
* number of reserved allocations is maintained by the mc_alloc_slots
|
||
|
|
* refcount. The mc_alloc_max_slots value determines the maximum
|
||
|
|
* number of allocations that the system allows. Gang blocks are
|
||
|
|
* allowed to reserve slots even if we've reached the maximum
|
||
|
|
* number of allocations allowed.
|
||
|
|
*/
|
||
|
|
uint64_t *mc_alloc_max_slots;
|
||
|
|
zfs_refcount_t *mc_alloc_slots;
|
||
|
|
|
||
|
|
uint64_t mc_alloc_groups; /* # of allocatable groups */
|
||
|
|
|
||
|
|
uint64_t mc_alloc; /* total allocated space */
|
||
|
|
uint64_t mc_deferred; /* total deferred frees */
|
||
|
|
uint64_t mc_space; /* total space (alloc + free) */
|
||
|
|
uint64_t mc_dspace; /* total deflated space */
|
||
|
|
uint64_t mc_histogram[RANGE_TREE_HISTOGRAM_SIZE];
|
||
|
|
};
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Metaslab groups encapsulate all the allocatable regions (i.e. metaslabs)
|
||
|
|
* of a top-level vdev. They are linked together to form a circular linked
|
||
|
|
* list and can belong to only one metaslab class. Metaslab groups may become
|
||
|
|
* ineligible for allocations for a number of reasons such as limited free
|
||
|
|
* space, fragmentation, or going offline. When this happens the allocator will
|
||
|
|
* simply find the next metaslab group in the linked list and attempt
|
||
|
|
* to allocate from that group instead.
|
||
|
|
*/
|
||
|
|
struct metaslab_group {
|
||
|
|
kmutex_t mg_lock;
|
||
|
|
metaslab_t **mg_primaries;
|
||
|
|
metaslab_t **mg_secondaries;
|
||
|
|
avl_tree_t mg_metaslab_tree;
|
||
|
|
uint64_t mg_aliquot;
|
||
|
|
boolean_t mg_allocatable; /* can we allocate? */
|
||
|
|
uint64_t mg_ms_ready;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* A metaslab group is considered to be initialized only after
|
||
|
|
* we have updated the MOS config and added the space to the pool.
|
||
|
|
* We only allow allocation attempts to a metaslab group if it
|
||
|
|
* has been initialized.
|
||
|
|
*/
|
||
|
|
boolean_t mg_initialized;
|
||
|
|
|
||
|
|
uint64_t mg_free_capacity; /* percentage free */
|
||
|
|
int64_t mg_bias;
|
||
|
|
int64_t mg_activation_count;
|
||
|
|
metaslab_class_t *mg_class;
|
||
|
|
vdev_t *mg_vd;
|
||
|
|
taskq_t *mg_taskq;
|
||
|
|
metaslab_group_t *mg_prev;
|
||
|
|
metaslab_group_t *mg_next;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* In order for the allocation throttle to function properly, we cannot
|
||
|
|
* have too many IOs going to each disk by default; the throttle
|
||
|
|
* operates by allocating more work to disks that finish quickly, so
|
||
|
|
* allocating larger chunks to each disk reduces its effectiveness.
|
||
|
|
* However, if the number of IOs going to each allocator is too small,
|
||
|
|
* we will not perform proper aggregation at the vdev_queue layer,
|
||
|
|
* also resulting in decreased performance. Therefore, we will use a
|
||
|
|
* ramp-up strategy.
|
||
|
|
*
|
||
|
|
* Each allocator in each metaslab group has a current queue depth
|
||
|
|
* (mg_alloc_queue_depth[allocator]) and a current max queue depth
|
||
|
|
* (mg_cur_max_alloc_queue_depth[allocator]), and each metaslab group
|
||
|
|
* has an absolute max queue depth (mg_max_alloc_queue_depth). We
|
||
|
|
* add IOs to an allocator until the mg_alloc_queue_depth for that
|
||
|
|
* allocator hits the cur_max. Every time an IO completes for a given
|
||
|
|
* allocator on a given metaslab group, we increment its cur_max until
|
||
|
|
* it reaches mg_max_alloc_queue_depth. The cur_max resets every txg to
|
||
|
|
* help protect against disks that decrease in performance over time.
|
||
|
|
*
|
||
|
|
* It's possible for an allocator to handle more allocations than
|
||
|
|
* its max. This can occur when gang blocks are required or when other
|
||
|
|
* groups are unable to handle their share of allocations.
|
||
|
|
*/
|
||
|
|
uint64_t mg_max_alloc_queue_depth;
|
||
|
|
uint64_t *mg_cur_max_alloc_queue_depth;
|
||
|
|
zfs_refcount_t *mg_alloc_queue_depth;
|
||
|
|
int mg_allocators;
|
||
|
|
/*
|
||
|
|
* A metalab group that can no longer allocate the minimum block
|
||
|
|
* size will set mg_no_free_space. Once a metaslab group is out
|
||
|
|
* of space then its share of work must be distributed to other
|
||
|
|
* groups.
|
||
|
|
*/
|
||
|
|
boolean_t mg_no_free_space;
|
||
|
|
|
||
|
|
uint64_t mg_allocations;
|
||
|
|
uint64_t mg_failed_allocations;
|
||
|
|
uint64_t mg_fragmentation;
|
||
|
|
uint64_t mg_histogram[RANGE_TREE_HISTOGRAM_SIZE];
|
||
|
|
|
||
|
|
int mg_ms_disabled;
|
||
|
|
boolean_t mg_disabled_updating;
|
||
|
|
kmutex_t mg_ms_disabled_lock;
|
||
|
|
kcondvar_t mg_ms_disabled_cv;
|
||
|
|
};
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This value defines the number of elements in the ms_lbas array. The value
|
||
|
|
* of 64 was chosen as it covers all power of 2 buckets up to UINT64_MAX.
|
||
|
|
* This is the equivalent of highbit(UINT64_MAX).
|
||
|
|
*/
|
||
|
|
#define MAX_LBAS 64
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Each metaslab maintains a set of in-core trees to track metaslab
|
||
|
|
* operations. The in-core free tree (ms_allocatable) contains the list of
|
||
|
|
* free segments which are eligible for allocation. As blocks are
|
||
|
|
* allocated, the allocated segment are removed from the ms_allocatable and
|
||
|
|
* added to a per txg allocation tree (ms_allocating). As blocks are
|
||
|
|
* freed, they are added to the free tree (ms_freeing). These trees
|
||
|
|
* allow us to process all allocations and frees in syncing context
|
||
|
|
* where it is safe to update the on-disk space maps. An additional set
|
||
|
|
* of in-core trees is maintained to track deferred frees
|
||
|
|
* (ms_defer). Once a block is freed it will move from the
|
||
|
|
* ms_freed to the ms_defer tree. A deferred free means that a block
|
||
|
|
* has been freed but cannot be used by the pool until TXG_DEFER_SIZE
|
||
|
|
* transactions groups later. For example, a block that is freed in txg
|
||
|
|
* 50 will not be available for reallocation until txg 52 (50 +
|
||
|
|
* TXG_DEFER_SIZE). This provides a safety net for uberblock rollback.
|
||
|
|
* A pool could be safely rolled back TXG_DEFERS_SIZE transactions
|
||
|
|
* groups and ensure that no block has been reallocated.
|
||
|
|
*
|
||
|
|
* The simplified transition diagram looks like this:
|
||
|
|
*
|
||
|
|
*
|
||
|
|
* ALLOCATE
|
||
|
|
* |
|
||
|
|
* V
|
||
|
|
* free segment (ms_allocatable) -> ms_allocating[4] -> (write to space map)
|
||
|
|
* ^
|
||
|
|
* | ms_freeing <--- FREE
|
||
|
|
* | |
|
||
|
|
* | v
|
||
|
|
* | ms_freed
|
||
|
|
* | |
|
||
|
|
* +-------- ms_defer[2] <-------+-------> (write to space map)
|
||
|
|
*
|
||
|
|
*
|
||
|
|
* Each metaslab's space is tracked in a single space map in the MOS,
|
||
|
|
* which is only updated in syncing context. Each time we sync a txg,
|
||
|
|
* we append the allocs and frees from that txg to the space map. The
|
||
|
|
* pool space is only updated once all metaslabs have finished syncing.
|
||
|
|
*
|
||
|
|
* To load the in-core free tree we read the space map from disk. This
|
||
|
|
* object contains a series of alloc and free records that are combined
|
||
|
|
* to make up the list of all free segments in this metaslab. These
|
||
|
|
* segments are represented in-core by the ms_allocatable and are stored
|
||
|
|
* in an AVL tree.
|
||
|
|
*
|
||
|
|
* As the space map grows (as a result of the appends) it will
|
||
|
|
* eventually become space-inefficient. When the metaslab's in-core
|
||
|
|
* free tree is zfs_condense_pct/100 times the size of the minimal
|
||
|
|
* on-disk representation, we rewrite it in its minimized form. If a
|
||
|
|
* metaslab needs to condense then we must set the ms_condensing flag to
|
||
|
|
* ensure that allocations are not performed on the metaslab that is
|
||
|
|
* being written.
|
||
|
|
*/
|
||
|
|
struct metaslab {
|
||
|
|
/*
|
||
|
|
* This is the main lock of the metaslab and its purpose is to
|
||
|
|
* coordinate our allocations and frees [e.g metaslab_block_alloc(),
|
||
|
|
* metaslab_free_concrete(), ..etc] with our various syncing
|
||
|
|
* procedures [e.g. metaslab_sync(), metaslab_sync_done(), ..etc].
|
||
|
|
*
|
||
|
|
* The lock is also used during some miscellaneous operations like
|
||
|
|
* using the metaslab's histogram for the metaslab group's histogram
|
||
|
|
* aggregation, or marking the metaslab for initialization.
|
||
|
|
*/
|
||
|
|
kmutex_t ms_lock;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Acquired together with the ms_lock whenever we expect to
|
||
|
|
* write to metaslab data on-disk (i.e flushing entries to
|
||
|
|
* the metaslab's space map). It helps coordinate readers of
|
||
|
|
* the metaslab's space map [see spa_vdev_remove_thread()]
|
||
|
|
* with writers [see metaslab_sync()].
|
||
|
|
*
|
||
|
|
* Note that metaslab_load(), even though a reader, uses
|
||
|
|
* a completely different mechanism to deal with the reading
|
||
|
|
* of the metaslab's space map based on ms_synced_length. That
|
||
|
|
* said, the function still uses the ms_sync_lock after it
|
||
|
|
* has read the ms_sm [see relevant comment in metaslab_load()
|
||
|
|
* as to why].
|
||
|
|
*/
|
||
|
|
kmutex_t ms_sync_lock;
|
||
|
|
|
||
|
|
kcondvar_t ms_load_cv;
|
||
|
|
space_map_t *ms_sm;
|
||
|
|
uint64_t ms_id;
|
||
|
|
uint64_t ms_start;
|
||
|
|
uint64_t ms_size;
|
||
|
|
uint64_t ms_fragmentation;
|
||
|
|
|
||
|
|
range_tree_t *ms_allocating[TXG_SIZE];
|
||
|
|
range_tree_t *ms_allocatable;
|
||
|
|
uint64_t ms_allocated_this_txg;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The following range trees are accessed only from syncing context.
|
||
|
|
* ms_free*tree only have entries while syncing, and are empty
|
||
|
|
* between syncs.
|
||
|
|
*/
|
||
|
|
range_tree_t *ms_freeing; /* to free this syncing txg */
|
||
|
|
range_tree_t *ms_freed; /* already freed this syncing txg */
|
||
|
|
range_tree_t *ms_defer[TXG_DEFER_SIZE];
|
||
|
|
range_tree_t *ms_checkpointing; /* to add to the checkpoint */
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The ms_trim tree is the set of allocatable segments which are
|
||
|
|
* eligible for trimming. (When the metaslab is loaded, it's a
|
||
|
|
* subset of ms_allocatable.) It's kept in-core as long as the
|
||
|
|
* autotrim property is set and is not vacated when the metaslab
|
||
|
|
* is unloaded. Its purpose is to aggregate freed ranges to
|
||
|
|
* facilitate efficient trimming.
|
||
|
|
*/
|
||
|
|
range_tree_t *ms_trim;
|
||
|
|
|
||
|
|
boolean_t ms_condensing; /* condensing? */
|
||
|
|
boolean_t ms_condense_wanted;
|
||
|
|
uint64_t ms_condense_checked_txg;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The number of consumers which have disabled the metaslab.
|
||
|
|
*/
|
||
|
|
uint64_t ms_disabled;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* We must always hold the ms_lock when modifying ms_loaded
|
||
|
|
* and ms_loading.
|
||
|
|
*/
|
||
|
|
boolean_t ms_loaded;
|
||
|
|
boolean_t ms_loading;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The following histograms count entries that are in the
|
||
|
|
* metaslab's space map (and its histogram) but are not in
|
||
|
|
* ms_allocatable yet, because they are in ms_freed, ms_freeing,
|
||
|
|
* or ms_defer[].
|
||
|
|
*
|
||
|
|
* When the metaslab is not loaded, its ms_weight needs to
|
||
|
|
* reflect what is allocatable (i.e. what will be part of
|
||
|
|
* ms_allocatable if it is loaded). The weight is computed from
|
||
|
|
* the spacemap histogram, but that includes ranges that are
|
||
|
|
* not yet allocatable (because they are in ms_freed,
|
||
|
|
* ms_freeing, or ms_defer[]). Therefore, when calculating the
|
||
|
|
* weight, we need to remove those ranges.
|
||
|
|
*
|
||
|
|
* The ranges in the ms_freed and ms_defer[] range trees are all
|
||
|
|
* present in the spacemap. However, the spacemap may have
|
||
|
|
* multiple entries to represent a contiguous range, because it
|
||
|
|
* is written across multiple sync passes, but the changes of
|
||
|
|
* all sync passes are consolidated into the range trees.
|
||
|
|
* Adjacent ranges that are freed in different sync passes of
|
||
|
|
* one txg will be represented separately (as 2 or more entries)
|
||
|
|
* in the space map (and its histogram), but these adjacent
|
||
|
|
* ranges will be consolidated (represented as one entry) in the
|
||
|
|
* ms_freed/ms_defer[] range trees (and their histograms).
|
||
|
|
*
|
||
|
|
* When calculating the weight, we can not simply subtract the
|
||
|
|
* range trees' histograms from the spacemap's histogram,
|
||
|
|
* because the range trees' histograms may have entries in
|
||
|
|
* higher buckets than the spacemap, due to consolidation.
|
||
|
|
* Instead we must subtract the exact entries that were added to
|
||
|
|
* the spacemap's histogram. ms_synchist and ms_deferhist[]
|
||
|
|
* represent these exact entries, so we can subtract them from
|
||
|
|
* the spacemap's histogram when calculating ms_weight.
|
||
|
|
*
|
||
|
|
* ms_synchist represents the same ranges as ms_freeing +
|
||
|
|
* ms_freed, but without consolidation across sync passes.
|
||
|
|
*
|
||
|
|
* ms_deferhist[i] represents the same ranges as ms_defer[i],
|
||
|
|
* but without consolidation across sync passes.
|
||
|
|
*/
|
||
|
|
uint64_t ms_synchist[SPACE_MAP_HISTOGRAM_SIZE];
|
||
|
|
uint64_t ms_deferhist[TXG_DEFER_SIZE][SPACE_MAP_HISTOGRAM_SIZE];
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Tracks the exact amount of allocated space of this metaslab
|
||
|
|
* (and specifically the metaslab's space map) up to the most
|
||
|
|
* recently completed sync pass [see usage in metaslab_sync()].
|
||
|
|
*/
|
||
|
|
uint64_t ms_allocated_space;
|
||
|
|
int64_t ms_deferspace; /* sum of ms_defermap[] space */
|
||
|
|
uint64_t ms_weight; /* weight vs. others in group */
|
||
|
|
uint64_t ms_activation_weight; /* activation weight */
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Track of whenever a metaslab is selected for loading or allocation.
|
||
|
|
* We use this value to determine how long the metaslab should
|
||
|
|
* stay cached.
|
||
|
|
*/
|
||
|
|
uint64_t ms_selected_txg;
|
||
|
|
|
||
|
|
uint64_t ms_alloc_txg; /* last successful alloc (debug only) */
|
||
|
|
uint64_t ms_max_size; /* maximum allocatable size */
|
||
|
|
|
||
|
|
/*
|
||
|
|
* -1 if it's not active in an allocator, otherwise set to the allocator
|
||
|
|
* this metaslab is active for.
|
||
|
|
*/
|
||
|
|
int ms_allocator;
|
||
|
|
boolean_t ms_primary; /* Only valid if ms_allocator is not -1 */
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The metaslab block allocators can optionally use a size-ordered
|
||
|
|
* range tree and/or an array of LBAs. Not all allocators use
|
||
|
|
* this functionality. The ms_allocatable_by_size should always
|
||
|
|
* contain the same number of segments as the ms_allocatable. The
|
||
|
|
* only difference is that the ms_allocatable_by_size is ordered by
|
||
|
|
* segment sizes.
|
||
|
|
*/
|
||
|
|
avl_tree_t ms_allocatable_by_size;
|
||
|
|
uint64_t ms_lbas[MAX_LBAS];
|
||
|
|
|
||
|
|
metaslab_group_t *ms_group; /* metaslab group */
|
||
|
|
avl_node_t ms_group_node; /* node in metaslab group tree */
|
||
|
|
txg_node_t ms_txg_node; /* per-txg dirty metaslab links */
|
||
|
|
|
||
|
|
/* updated every time we are done syncing the metaslab's space map */
|
||
|
|
uint64_t ms_synced_length;
|
||
|
|
|
||
|
|
boolean_t ms_new;
|
||
|
|
};
|
||
|
|
|
||
|
|
#ifdef __cplusplus
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#endif /* _SYS_METASLAB_IMPL_H */
|