4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
24 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
25 * Copyright (c) 2014 Integros [integros.com]
28 #include <sys/zfs_context.h>
30 #include <sys/dmu_tx.h>
31 #include <sys/space_map.h>
32 #include <sys/metaslab_impl.h>
33 #include <sys/vdev_impl.h>
35 #include <sys/spa_impl.h>
36 #include <sys/zfeature.h>
37 #include <sys/vdev_indirect_mapping.h>
39 #define GANG_ALLOCATION(flags) \
40 ((flags) & (METASLAB_GANG_CHILD | METASLAB_GANG_HEADER))
42 uint64_t metaslab_aliquot
= 512ULL << 10;
43 uint64_t metaslab_gang_bang
= SPA_MAXBLOCKSIZE
+ 1; /* force gang blocks */
46 * The in-core space map representation is more compact than its on-disk form.
47 * The zfs_condense_pct determines how much more compact the in-core
48 * space map representation must be before we compact it on-disk.
49 * Values should be greater than or equal to 100.
51 int zfs_condense_pct
= 200;
54 * Condensing a metaslab is not guaranteed to actually reduce the amount of
55 * space used on disk. In particular, a space map uses data in increments of
56 * MAX(1 << ashift, space_map_blksize), so a metaslab might use the
57 * same number of blocks after condensing. Since the goal of condensing is to
58 * reduce the number of IOPs required to read the space map, we only want to
59 * condense when we can be sure we will reduce the number of blocks used by the
60 * space map. Unfortunately, we cannot precisely compute whether or not this is
61 * the case in metaslab_should_condense since we are holding ms_lock. Instead,
62 * we apply the following heuristic: do not condense a spacemap unless the
63 * uncondensed size consumes greater than zfs_metaslab_condense_block_threshold
66 int zfs_metaslab_condense_block_threshold
= 4;
69 * The zfs_mg_noalloc_threshold defines which metaslab groups should
70 * be eligible for allocation. The value is defined as a percentage of
71 * free space. Metaslab groups that have more free space than
72 * zfs_mg_noalloc_threshold are always eligible for allocations. Once
73 * a metaslab group's free space is less than or equal to the
74 * zfs_mg_noalloc_threshold the allocator will avoid allocating to that
75 * group unless all groups in the pool have reached zfs_mg_noalloc_threshold.
76 * Once all groups in the pool reach zfs_mg_noalloc_threshold then all
77 * groups are allowed to accept allocations. Gang blocks are always
78 * eligible to allocate on any metaslab group. The default value of 0 means
79 * no metaslab group will be excluded based on this criterion.
81 int zfs_mg_noalloc_threshold
= 0;
84 * Metaslab groups are considered eligible for allocations if their
85 * fragmenation metric (measured as a percentage) is less than or equal to
86 * zfs_mg_fragmentation_threshold. If a metaslab group exceeds this threshold
87 * then it will be skipped unless all metaslab groups within the metaslab
88 * class have also crossed this threshold.
90 int zfs_mg_fragmentation_threshold
= 85;
93 * Allow metaslabs to keep their active state as long as their fragmentation
94 * percentage is less than or equal to zfs_metaslab_fragmentation_threshold. An
95 * active metaslab that exceeds this threshold will no longer keep its active
96 * status allowing better metaslabs to be selected.
98 int zfs_metaslab_fragmentation_threshold
= 70;
101 * When set will load all metaslabs when pool is first opened.
103 int metaslab_debug_load
= 0;
106 * When set will prevent metaslabs from being unloaded.
108 int metaslab_debug_unload
= 0;
111 * Minimum size which forces the dynamic allocator to change
112 * it's allocation strategy. Once the space map cannot satisfy
113 * an allocation of this size then it switches to using more
114 * aggressive strategy (i.e search by size rather than offset).
116 uint64_t metaslab_df_alloc_threshold
= SPA_OLD_MAXBLOCKSIZE
;
119 * The minimum free space, in percent, which must be available
120 * in a space map to continue allocations in a first-fit fashion.
121 * Once the space map's free space drops below this level we dynamically
122 * switch to using best-fit allocations.
124 int metaslab_df_free_pct
= 4;
127 * A metaslab is considered "free" if it contains a contiguous
128 * segment which is greater than metaslab_min_alloc_size.
130 uint64_t metaslab_min_alloc_size
= DMU_MAX_ACCESS
;
133 * Percentage of all cpus that can be used by the metaslab taskq.
135 int metaslab_load_pct
= 50;
138 * Determines how many txgs a metaslab may remain loaded without having any
139 * allocations from it. As long as a metaslab continues to be used we will
142 int metaslab_unload_delay
= TXG_SIZE
* 2;
145 * Max number of metaslabs per group to preload.
147 int metaslab_preload_limit
= SPA_DVAS_PER_BP
;
150 * Enable/disable preloading of metaslab.
152 boolean_t metaslab_preload_enabled
= B_TRUE
;
155 * Enable/disable fragmentation weighting on metaslabs.
157 boolean_t metaslab_fragmentation_factor_enabled
= B_TRUE
;
160 * Enable/disable lba weighting (i.e. outer tracks are given preference).
162 boolean_t metaslab_lba_weighting_enabled
= B_TRUE
;
165 * Enable/disable metaslab group biasing.
167 boolean_t metaslab_bias_enabled
= B_TRUE
;
170 * Enable/disable remapping of indirect DVAs to their concrete vdevs.
172 boolean_t zfs_remap_blkptr_enable
= B_TRUE
;
175 * Enable/disable segment-based metaslab selection.
177 boolean_t zfs_metaslab_segment_weight_enabled
= B_TRUE
;
180 * When using segment-based metaslab selection, we will continue
181 * allocating from the active metaslab until we have exhausted
182 * zfs_metaslab_switch_threshold of its buckets.
184 int zfs_metaslab_switch_threshold
= 2;
187 * Internal switch to enable/disable the metaslab allocation tracing
190 boolean_t metaslab_trace_enabled
= B_TRUE
;
193 * Maximum entries that the metaslab allocation tracing facility will keep
194 * in a given list when running in non-debug mode. We limit the number
195 * of entries in non-debug mode to prevent us from using up too much memory.
196 * The limit should be sufficiently large that we don't expect any allocation
197 * to every exceed this value. In debug mode, the system will panic if this
198 * limit is ever reached allowing for further investigation.
200 uint64_t metaslab_trace_max_entries
= 5000;
202 static uint64_t metaslab_weight(metaslab_t
*);
203 static void metaslab_set_fragmentation(metaslab_t
*);
204 static void metaslab_free_impl(vdev_t
*, uint64_t, uint64_t, uint64_t);
205 static void metaslab_check_free_impl(vdev_t
*, uint64_t, uint64_t);
207 kmem_cache_t
*metaslab_alloc_trace_cache
;
210 * ==========================================================================
212 * ==========================================================================
215 metaslab_class_create(spa_t
*spa
, metaslab_ops_t
*ops
)
217 metaslab_class_t
*mc
;
219 mc
= kmem_zalloc(sizeof (metaslab_class_t
), KM_SLEEP
);
224 mutex_init(&mc
->mc_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
225 refcount_create_tracked(&mc
->mc_alloc_slots
);
231 metaslab_class_destroy(metaslab_class_t
*mc
)
233 ASSERT(mc
->mc_rotor
== NULL
);
234 ASSERT(mc
->mc_alloc
== 0);
235 ASSERT(mc
->mc_deferred
== 0);
236 ASSERT(mc
->mc_space
== 0);
237 ASSERT(mc
->mc_dspace
== 0);
239 refcount_destroy(&mc
->mc_alloc_slots
);
240 mutex_destroy(&mc
->mc_lock
);
241 kmem_free(mc
, sizeof (metaslab_class_t
));
245 metaslab_class_validate(metaslab_class_t
*mc
)
247 metaslab_group_t
*mg
;
251 * Must hold one of the spa_config locks.
253 ASSERT(spa_config_held(mc
->mc_spa
, SCL_ALL
, RW_READER
) ||
254 spa_config_held(mc
->mc_spa
, SCL_ALL
, RW_WRITER
));
256 if ((mg
= mc
->mc_rotor
) == NULL
)
261 ASSERT(vd
->vdev_mg
!= NULL
);
262 ASSERT3P(vd
->vdev_top
, ==, vd
);
263 ASSERT3P(mg
->mg_class
, ==, mc
);
264 ASSERT3P(vd
->vdev_ops
, !=, &vdev_hole_ops
);
265 } while ((mg
= mg
->mg_next
) != mc
->mc_rotor
);
271 metaslab_class_space_update(metaslab_class_t
*mc
, int64_t alloc_delta
,
272 int64_t defer_delta
, int64_t space_delta
, int64_t dspace_delta
)
274 atomic_add_64(&mc
->mc_alloc
, alloc_delta
);
275 atomic_add_64(&mc
->mc_deferred
, defer_delta
);
276 atomic_add_64(&mc
->mc_space
, space_delta
);
277 atomic_add_64(&mc
->mc_dspace
, dspace_delta
);
281 metaslab_class_get_alloc(metaslab_class_t
*mc
)
283 return (mc
->mc_alloc
);
287 metaslab_class_get_deferred(metaslab_class_t
*mc
)
289 return (mc
->mc_deferred
);
293 metaslab_class_get_space(metaslab_class_t
*mc
)
295 return (mc
->mc_space
);
299 metaslab_class_get_dspace(metaslab_class_t
*mc
)
301 return (spa_deflate(mc
->mc_spa
) ? mc
->mc_dspace
: mc
->mc_space
);
305 metaslab_class_histogram_verify(metaslab_class_t
*mc
)
307 vdev_t
*rvd
= mc
->mc_spa
->spa_root_vdev
;
311 if ((zfs_flags
& ZFS_DEBUG_HISTOGRAM_VERIFY
) == 0)
314 mc_hist
= kmem_zalloc(sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE
,
317 for (int c
= 0; c
< rvd
->vdev_children
; c
++) {
318 vdev_t
*tvd
= rvd
->vdev_child
[c
];
319 metaslab_group_t
*mg
= tvd
->vdev_mg
;
322 * Skip any holes, uninitialized top-levels, or
323 * vdevs that are not in this metalab class.
325 if (!vdev_is_concrete(tvd
) || tvd
->vdev_ms_shift
== 0 ||
326 mg
->mg_class
!= mc
) {
330 for (i
= 0; i
< RANGE_TREE_HISTOGRAM_SIZE
; i
++)
331 mc_hist
[i
] += mg
->mg_histogram
[i
];
334 for (i
= 0; i
< RANGE_TREE_HISTOGRAM_SIZE
; i
++)
335 VERIFY3U(mc_hist
[i
], ==, mc
->mc_histogram
[i
]);
337 kmem_free(mc_hist
, sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE
);
341 * Calculate the metaslab class's fragmentation metric. The metric
342 * is weighted based on the space contribution of each metaslab group.
343 * The return value will be a number between 0 and 100 (inclusive), or
344 * ZFS_FRAG_INVALID if the metric has not been set. See comment above the
345 * zfs_frag_table for more information about the metric.
348 metaslab_class_fragmentation(metaslab_class_t
*mc
)
350 vdev_t
*rvd
= mc
->mc_spa
->spa_root_vdev
;
351 uint64_t fragmentation
= 0;
353 spa_config_enter(mc
->mc_spa
, SCL_VDEV
, FTAG
, RW_READER
);
355 for (int c
= 0; c
< rvd
->vdev_children
; c
++) {
356 vdev_t
*tvd
= rvd
->vdev_child
[c
];
357 metaslab_group_t
*mg
= tvd
->vdev_mg
;
360 * Skip any holes, uninitialized top-levels,
361 * or vdevs that are not in this metalab class.
363 if (!vdev_is_concrete(tvd
) || tvd
->vdev_ms_shift
== 0 ||
364 mg
->mg_class
!= mc
) {
369 * If a metaslab group does not contain a fragmentation
370 * metric then just bail out.
372 if (mg
->mg_fragmentation
== ZFS_FRAG_INVALID
) {
373 spa_config_exit(mc
->mc_spa
, SCL_VDEV
, FTAG
);
374 return (ZFS_FRAG_INVALID
);
378 * Determine how much this metaslab_group is contributing
379 * to the overall pool fragmentation metric.
381 fragmentation
+= mg
->mg_fragmentation
*
382 metaslab_group_get_space(mg
);
384 fragmentation
/= metaslab_class_get_space(mc
);
386 ASSERT3U(fragmentation
, <=, 100);
387 spa_config_exit(mc
->mc_spa
, SCL_VDEV
, FTAG
);
388 return (fragmentation
);
392 * Calculate the amount of expandable space that is available in
393 * this metaslab class. If a device is expanded then its expandable
394 * space will be the amount of allocatable space that is currently not
395 * part of this metaslab class.
398 metaslab_class_expandable_space(metaslab_class_t
*mc
)
400 vdev_t
*rvd
= mc
->mc_spa
->spa_root_vdev
;
403 spa_config_enter(mc
->mc_spa
, SCL_VDEV
, FTAG
, RW_READER
);
404 for (int c
= 0; c
< rvd
->vdev_children
; c
++) {
406 vdev_t
*tvd
= rvd
->vdev_child
[c
];
407 metaslab_group_t
*mg
= tvd
->vdev_mg
;
409 if (!vdev_is_concrete(tvd
) || tvd
->vdev_ms_shift
== 0 ||
410 mg
->mg_class
!= mc
) {
415 * Calculate if we have enough space to add additional
416 * metaslabs. We report the expandable space in terms
417 * of the metaslab size since that's the unit of expansion.
418 * Adjust by efi system partition size.
420 tspace
= tvd
->vdev_max_asize
- tvd
->vdev_asize
;
421 if (tspace
> mc
->mc_spa
->spa_bootsize
) {
422 tspace
-= mc
->mc_spa
->spa_bootsize
;
424 space
+= P2ALIGN(tspace
, 1ULL << tvd
->vdev_ms_shift
);
426 spa_config_exit(mc
->mc_spa
, SCL_VDEV
, FTAG
);
431 metaslab_compare(const void *x1
, const void *x2
)
433 const metaslab_t
*m1
= x1
;
434 const metaslab_t
*m2
= x2
;
436 if (m1
->ms_weight
< m2
->ms_weight
)
438 if (m1
->ms_weight
> m2
->ms_weight
)
442 * If the weights are identical, use the offset to force uniqueness.
444 if (m1
->ms_start
< m2
->ms_start
)
446 if (m1
->ms_start
> m2
->ms_start
)
449 ASSERT3P(m1
, ==, m2
);
455 * Verify that the space accounting on disk matches the in-core range_trees.
458 metaslab_verify_space(metaslab_t
*msp
, uint64_t txg
)
460 spa_t
*spa
= msp
->ms_group
->mg_vd
->vdev_spa
;
461 uint64_t allocated
= 0;
462 uint64_t sm_free_space
, msp_free_space
;
464 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
466 if ((zfs_flags
& ZFS_DEBUG_METASLAB_VERIFY
) == 0)
470 * We can only verify the metaslab space when we're called
471 * from syncing context with a loaded metaslab that has an allocated
472 * space map. Calling this in non-syncing context does not
473 * provide a consistent view of the metaslab since we're performing
474 * allocations in the future.
476 if (txg
!= spa_syncing_txg(spa
) || msp
->ms_sm
== NULL
||
480 sm_free_space
= msp
->ms_size
- space_map_allocated(msp
->ms_sm
) -
481 space_map_alloc_delta(msp
->ms_sm
);
484 * Account for future allocations since we would have already
485 * deducted that space from the ms_freetree.
487 for (int t
= 0; t
< TXG_CONCURRENT_STATES
; t
++) {
489 range_tree_space(msp
->ms_alloctree
[(txg
+ t
) & TXG_MASK
]);
492 msp_free_space
= range_tree_space(msp
->ms_tree
) + allocated
+
493 msp
->ms_deferspace
+ range_tree_space(msp
->ms_freedtree
);
495 VERIFY3U(sm_free_space
, ==, msp_free_space
);
499 * ==========================================================================
501 * ==========================================================================
504 * Update the allocatable flag and the metaslab group's capacity.
505 * The allocatable flag is set to true if the capacity is below
506 * the zfs_mg_noalloc_threshold or has a fragmentation value that is
507 * greater than zfs_mg_fragmentation_threshold. If a metaslab group
508 * transitions from allocatable to non-allocatable or vice versa then the
509 * metaslab group's class is updated to reflect the transition.
512 metaslab_group_alloc_update(metaslab_group_t
*mg
)
514 vdev_t
*vd
= mg
->mg_vd
;
515 metaslab_class_t
*mc
= mg
->mg_class
;
516 vdev_stat_t
*vs
= &vd
->vdev_stat
;
517 boolean_t was_allocatable
;
518 boolean_t was_initialized
;
520 ASSERT(vd
== vd
->vdev_top
);
521 ASSERT3U(spa_config_held(mc
->mc_spa
, SCL_ALLOC
, RW_READER
), ==,
524 mutex_enter(&mg
->mg_lock
);
525 was_allocatable
= mg
->mg_allocatable
;
526 was_initialized
= mg
->mg_initialized
;
528 mg
->mg_free_capacity
= ((vs
->vs_space
- vs
->vs_alloc
) * 100) /
531 mutex_enter(&mc
->mc_lock
);
534 * If the metaslab group was just added then it won't
535 * have any space until we finish syncing out this txg.
536 * At that point we will consider it initialized and available
537 * for allocations. We also don't consider non-activated
538 * metaslab groups (e.g. vdevs that are in the middle of being removed)
539 * to be initialized, because they can't be used for allocation.
541 mg
->mg_initialized
= metaslab_group_initialized(mg
);
542 if (!was_initialized
&& mg
->mg_initialized
) {
544 } else if (was_initialized
&& !mg
->mg_initialized
) {
545 ASSERT3U(mc
->mc_groups
, >, 0);
548 if (mg
->mg_initialized
)
549 mg
->mg_no_free_space
= B_FALSE
;
552 * A metaslab group is considered allocatable if it has plenty
553 * of free space or is not heavily fragmented. We only take
554 * fragmentation into account if the metaslab group has a valid
555 * fragmentation metric (i.e. a value between 0 and 100).
557 mg
->mg_allocatable
= (mg
->mg_activation_count
> 0 &&
558 mg
->mg_free_capacity
> zfs_mg_noalloc_threshold
&&
559 (mg
->mg_fragmentation
== ZFS_FRAG_INVALID
||
560 mg
->mg_fragmentation
<= zfs_mg_fragmentation_threshold
));
563 * The mc_alloc_groups maintains a count of the number of
564 * groups in this metaslab class that are still above the
565 * zfs_mg_noalloc_threshold. This is used by the allocating
566 * threads to determine if they should avoid allocations to
567 * a given group. The allocator will avoid allocations to a group
568 * if that group has reached or is below the zfs_mg_noalloc_threshold
569 * and there are still other groups that are above the threshold.
570 * When a group transitions from allocatable to non-allocatable or
571 * vice versa we update the metaslab class to reflect that change.
572 * When the mc_alloc_groups value drops to 0 that means that all
573 * groups have reached the zfs_mg_noalloc_threshold making all groups
574 * eligible for allocations. This effectively means that all devices
575 * are balanced again.
577 if (was_allocatable
&& !mg
->mg_allocatable
)
578 mc
->mc_alloc_groups
--;
579 else if (!was_allocatable
&& mg
->mg_allocatable
)
580 mc
->mc_alloc_groups
++;
581 mutex_exit(&mc
->mc_lock
);
583 mutex_exit(&mg
->mg_lock
);
587 metaslab_group_create(metaslab_class_t
*mc
, vdev_t
*vd
)
589 metaslab_group_t
*mg
;
591 mg
= kmem_zalloc(sizeof (metaslab_group_t
), KM_SLEEP
);
592 mutex_init(&mg
->mg_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
593 avl_create(&mg
->mg_metaslab_tree
, metaslab_compare
,
594 sizeof (metaslab_t
), offsetof(struct metaslab
, ms_group_node
));
597 mg
->mg_activation_count
= 0;
598 mg
->mg_initialized
= B_FALSE
;
599 mg
->mg_no_free_space
= B_TRUE
;
600 refcount_create_tracked(&mg
->mg_alloc_queue_depth
);
602 mg
->mg_taskq
= taskq_create("metaslab_group_taskq", metaslab_load_pct
,
603 minclsyspri
, 10, INT_MAX
, TASKQ_THREADS_CPU_PCT
);
609 metaslab_group_destroy(metaslab_group_t
*mg
)
611 ASSERT(mg
->mg_prev
== NULL
);
612 ASSERT(mg
->mg_next
== NULL
);
614 * We may have gone below zero with the activation count
615 * either because we never activated in the first place or
616 * because we're done, and possibly removing the vdev.
618 ASSERT(mg
->mg_activation_count
<= 0);
620 taskq_destroy(mg
->mg_taskq
);
621 avl_destroy(&mg
->mg_metaslab_tree
);
622 mutex_destroy(&mg
->mg_lock
);
623 refcount_destroy(&mg
->mg_alloc_queue_depth
);
624 kmem_free(mg
, sizeof (metaslab_group_t
));
628 metaslab_group_activate(metaslab_group_t
*mg
)
630 metaslab_class_t
*mc
= mg
->mg_class
;
631 metaslab_group_t
*mgprev
, *mgnext
;
633 ASSERT3U(spa_config_held(mc
->mc_spa
, SCL_ALLOC
, RW_WRITER
), !=, 0);
635 ASSERT(mc
->mc_rotor
!= mg
);
636 ASSERT(mg
->mg_prev
== NULL
);
637 ASSERT(mg
->mg_next
== NULL
);
638 ASSERT(mg
->mg_activation_count
<= 0);
640 if (++mg
->mg_activation_count
<= 0)
643 mg
->mg_aliquot
= metaslab_aliquot
* MAX(1, mg
->mg_vd
->vdev_children
);
644 metaslab_group_alloc_update(mg
);
646 if ((mgprev
= mc
->mc_rotor
) == NULL
) {
650 mgnext
= mgprev
->mg_next
;
651 mg
->mg_prev
= mgprev
;
652 mg
->mg_next
= mgnext
;
653 mgprev
->mg_next
= mg
;
654 mgnext
->mg_prev
= mg
;
660 * Passivate a metaslab group and remove it from the allocation rotor.
661 * Callers must hold both the SCL_ALLOC and SCL_ZIO lock prior to passivating
662 * a metaslab group. This function will momentarily drop spa_config_locks
663 * that are lower than the SCL_ALLOC lock (see comment below).
666 metaslab_group_passivate(metaslab_group_t
*mg
)
668 metaslab_class_t
*mc
= mg
->mg_class
;
669 spa_t
*spa
= mc
->mc_spa
;
670 metaslab_group_t
*mgprev
, *mgnext
;
671 int locks
= spa_config_held(spa
, SCL_ALL
, RW_WRITER
);
673 ASSERT3U(spa_config_held(spa
, SCL_ALLOC
| SCL_ZIO
, RW_WRITER
), ==,
674 (SCL_ALLOC
| SCL_ZIO
));
676 if (--mg
->mg_activation_count
!= 0) {
677 ASSERT(mc
->mc_rotor
!= mg
);
678 ASSERT(mg
->mg_prev
== NULL
);
679 ASSERT(mg
->mg_next
== NULL
);
680 ASSERT(mg
->mg_activation_count
< 0);
685 * The spa_config_lock is an array of rwlocks, ordered as
686 * follows (from highest to lowest):
687 * SCL_CONFIG > SCL_STATE > SCL_L2ARC > SCL_ALLOC >
688 * SCL_ZIO > SCL_FREE > SCL_VDEV
689 * (For more information about the spa_config_lock see spa_misc.c)
690 * The higher the lock, the broader its coverage. When we passivate
691 * a metaslab group, we must hold both the SCL_ALLOC and the SCL_ZIO
692 * config locks. However, the metaslab group's taskq might be trying
693 * to preload metaslabs so we must drop the SCL_ZIO lock and any
694 * lower locks to allow the I/O to complete. At a minimum,
695 * we continue to hold the SCL_ALLOC lock, which prevents any future
696 * allocations from taking place and any changes to the vdev tree.
698 spa_config_exit(spa
, locks
& ~(SCL_ZIO
- 1), spa
);
699 taskq_wait(mg
->mg_taskq
);
700 spa_config_enter(spa
, locks
& ~(SCL_ZIO
- 1), spa
, RW_WRITER
);
701 metaslab_group_alloc_update(mg
);
703 mgprev
= mg
->mg_prev
;
704 mgnext
= mg
->mg_next
;
709 mc
->mc_rotor
= mgnext
;
710 mgprev
->mg_next
= mgnext
;
711 mgnext
->mg_prev
= mgprev
;
719 metaslab_group_initialized(metaslab_group_t
*mg
)
721 vdev_t
*vd
= mg
->mg_vd
;
722 vdev_stat_t
*vs
= &vd
->vdev_stat
;
724 return (vs
->vs_space
!= 0 && mg
->mg_activation_count
> 0);
728 metaslab_group_get_space(metaslab_group_t
*mg
)
730 return ((1ULL << mg
->mg_vd
->vdev_ms_shift
) * mg
->mg_vd
->vdev_ms_count
);
734 metaslab_group_histogram_verify(metaslab_group_t
*mg
)
737 vdev_t
*vd
= mg
->mg_vd
;
738 uint64_t ashift
= vd
->vdev_ashift
;
741 if ((zfs_flags
& ZFS_DEBUG_HISTOGRAM_VERIFY
) == 0)
744 mg_hist
= kmem_zalloc(sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE
,
747 ASSERT3U(RANGE_TREE_HISTOGRAM_SIZE
, >=,
748 SPACE_MAP_HISTOGRAM_SIZE
+ ashift
);
750 for (int m
= 0; m
< vd
->vdev_ms_count
; m
++) {
751 metaslab_t
*msp
= vd
->vdev_ms
[m
];
753 if (msp
->ms_sm
== NULL
)
756 for (i
= 0; i
< SPACE_MAP_HISTOGRAM_SIZE
; i
++)
757 mg_hist
[i
+ ashift
] +=
758 msp
->ms_sm
->sm_phys
->smp_histogram
[i
];
761 for (i
= 0; i
< RANGE_TREE_HISTOGRAM_SIZE
; i
++)
762 VERIFY3U(mg_hist
[i
], ==, mg
->mg_histogram
[i
]);
764 kmem_free(mg_hist
, sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE
);
768 metaslab_group_histogram_add(metaslab_group_t
*mg
, metaslab_t
*msp
)
770 metaslab_class_t
*mc
= mg
->mg_class
;
771 uint64_t ashift
= mg
->mg_vd
->vdev_ashift
;
773 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
774 if (msp
->ms_sm
== NULL
)
777 mutex_enter(&mg
->mg_lock
);
778 for (int i
= 0; i
< SPACE_MAP_HISTOGRAM_SIZE
; i
++) {
779 mg
->mg_histogram
[i
+ ashift
] +=
780 msp
->ms_sm
->sm_phys
->smp_histogram
[i
];
781 mc
->mc_histogram
[i
+ ashift
] +=
782 msp
->ms_sm
->sm_phys
->smp_histogram
[i
];
784 mutex_exit(&mg
->mg_lock
);
788 metaslab_group_histogram_remove(metaslab_group_t
*mg
, metaslab_t
*msp
)
790 metaslab_class_t
*mc
= mg
->mg_class
;
791 uint64_t ashift
= mg
->mg_vd
->vdev_ashift
;
793 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
794 if (msp
->ms_sm
== NULL
)
797 mutex_enter(&mg
->mg_lock
);
798 for (int i
= 0; i
< SPACE_MAP_HISTOGRAM_SIZE
; i
++) {
799 ASSERT3U(mg
->mg_histogram
[i
+ ashift
], >=,
800 msp
->ms_sm
->sm_phys
->smp_histogram
[i
]);
801 ASSERT3U(mc
->mc_histogram
[i
+ ashift
], >=,
802 msp
->ms_sm
->sm_phys
->smp_histogram
[i
]);
804 mg
->mg_histogram
[i
+ ashift
] -=
805 msp
->ms_sm
->sm_phys
->smp_histogram
[i
];
806 mc
->mc_histogram
[i
+ ashift
] -=
807 msp
->ms_sm
->sm_phys
->smp_histogram
[i
];
809 mutex_exit(&mg
->mg_lock
);
813 metaslab_group_add(metaslab_group_t
*mg
, metaslab_t
*msp
)
815 ASSERT(msp
->ms_group
== NULL
);
816 mutex_enter(&mg
->mg_lock
);
819 avl_add(&mg
->mg_metaslab_tree
, msp
);
820 mutex_exit(&mg
->mg_lock
);
822 mutex_enter(&msp
->ms_lock
);
823 metaslab_group_histogram_add(mg
, msp
);
824 mutex_exit(&msp
->ms_lock
);
828 metaslab_group_remove(metaslab_group_t
*mg
, metaslab_t
*msp
)
830 mutex_enter(&msp
->ms_lock
);
831 metaslab_group_histogram_remove(mg
, msp
);
832 mutex_exit(&msp
->ms_lock
);
834 mutex_enter(&mg
->mg_lock
);
835 ASSERT(msp
->ms_group
== mg
);
836 avl_remove(&mg
->mg_metaslab_tree
, msp
);
837 msp
->ms_group
= NULL
;
838 mutex_exit(&mg
->mg_lock
);
842 metaslab_group_sort(metaslab_group_t
*mg
, metaslab_t
*msp
, uint64_t weight
)
845 * Although in principle the weight can be any value, in
846 * practice we do not use values in the range [1, 511].
848 ASSERT(weight
>= SPA_MINBLOCKSIZE
|| weight
== 0);
849 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
851 mutex_enter(&mg
->mg_lock
);
852 ASSERT(msp
->ms_group
== mg
);
853 avl_remove(&mg
->mg_metaslab_tree
, msp
);
854 msp
->ms_weight
= weight
;
855 avl_add(&mg
->mg_metaslab_tree
, msp
);
856 mutex_exit(&mg
->mg_lock
);
860 * Calculate the fragmentation for a given metaslab group. We can use
861 * a simple average here since all metaslabs within the group must have
862 * the same size. The return value will be a value between 0 and 100
863 * (inclusive), or ZFS_FRAG_INVALID if less than half of the metaslab in this
864 * group have a fragmentation metric.
867 metaslab_group_fragmentation(metaslab_group_t
*mg
)
869 vdev_t
*vd
= mg
->mg_vd
;
870 uint64_t fragmentation
= 0;
871 uint64_t valid_ms
= 0;
873 for (int m
= 0; m
< vd
->vdev_ms_count
; m
++) {
874 metaslab_t
*msp
= vd
->vdev_ms
[m
];
876 if (msp
->ms_fragmentation
== ZFS_FRAG_INVALID
)
880 fragmentation
+= msp
->ms_fragmentation
;
883 if (valid_ms
<= vd
->vdev_ms_count
/ 2)
884 return (ZFS_FRAG_INVALID
);
886 fragmentation
/= valid_ms
;
887 ASSERT3U(fragmentation
, <=, 100);
888 return (fragmentation
);
892 * Determine if a given metaslab group should skip allocations. A metaslab
893 * group should avoid allocations if its free capacity is less than the
894 * zfs_mg_noalloc_threshold or its fragmentation metric is greater than
895 * zfs_mg_fragmentation_threshold and there is at least one metaslab group
896 * that can still handle allocations. If the allocation throttle is enabled
897 * then we skip allocations to devices that have reached their maximum
898 * allocation queue depth unless the selected metaslab group is the only
899 * eligible group remaining.
902 metaslab_group_allocatable(metaslab_group_t
*mg
, metaslab_group_t
*rotor
,
905 spa_t
*spa
= mg
->mg_vd
->vdev_spa
;
906 metaslab_class_t
*mc
= mg
->mg_class
;
909 * We can only consider skipping this metaslab group if it's
910 * in the normal metaslab class and there are other metaslab
911 * groups to select from. Otherwise, we always consider it eligible
914 if (mc
!= spa_normal_class(spa
) || mc
->mc_groups
<= 1)
918 * If the metaslab group's mg_allocatable flag is set (see comments
919 * in metaslab_group_alloc_update() for more information) and
920 * the allocation throttle is disabled then allow allocations to this
921 * device. However, if the allocation throttle is enabled then
922 * check if we have reached our allocation limit (mg_alloc_queue_depth)
923 * to determine if we should allow allocations to this metaslab group.
924 * If all metaslab groups are no longer considered allocatable
925 * (mc_alloc_groups == 0) or we're trying to allocate the smallest
926 * gang block size then we allow allocations on this metaslab group
927 * regardless of the mg_allocatable or throttle settings.
929 if (mg
->mg_allocatable
) {
930 metaslab_group_t
*mgp
;
932 uint64_t qmax
= mg
->mg_max_alloc_queue_depth
;
934 if (!mc
->mc_alloc_throttle_enabled
)
938 * If this metaslab group does not have any free space, then
939 * there is no point in looking further.
941 if (mg
->mg_no_free_space
)
944 qdepth
= refcount_count(&mg
->mg_alloc_queue_depth
);
947 * If this metaslab group is below its qmax or it's
948 * the only allocatable metasable group, then attempt
949 * to allocate from it.
951 if (qdepth
< qmax
|| mc
->mc_alloc_groups
== 1)
953 ASSERT3U(mc
->mc_alloc_groups
, >, 1);
956 * Since this metaslab group is at or over its qmax, we
957 * need to determine if there are metaslab groups after this
958 * one that might be able to handle this allocation. This is
959 * racy since we can't hold the locks for all metaslab
960 * groups at the same time when we make this check.
962 for (mgp
= mg
->mg_next
; mgp
!= rotor
; mgp
= mgp
->mg_next
) {
963 qmax
= mgp
->mg_max_alloc_queue_depth
;
965 qdepth
= refcount_count(&mgp
->mg_alloc_queue_depth
);
968 * If there is another metaslab group that
969 * might be able to handle the allocation, then
970 * we return false so that we skip this group.
972 if (qdepth
< qmax
&& !mgp
->mg_no_free_space
)
977 * We didn't find another group to handle the allocation
978 * so we can't skip this metaslab group even though
979 * we are at or over our qmax.
983 } else if (mc
->mc_alloc_groups
== 0 || psize
== SPA_MINBLOCKSIZE
) {
990 * ==========================================================================
991 * Range tree callbacks
992 * ==========================================================================
996 * Comparison function for the private size-ordered tree. Tree is sorted
997 * by size, larger sizes at the end of the tree.
1000 metaslab_rangesize_compare(const void *x1
, const void *x2
)
1002 const range_seg_t
*r1
= x1
;
1003 const range_seg_t
*r2
= x2
;
1004 uint64_t rs_size1
= r1
->rs_end
- r1
->rs_start
;
1005 uint64_t rs_size2
= r2
->rs_end
- r2
->rs_start
;
1007 if (rs_size1
< rs_size2
)
1009 if (rs_size1
> rs_size2
)
1012 if (r1
->rs_start
< r2
->rs_start
)
1015 if (r1
->rs_start
> r2
->rs_start
)
1022 * Create any block allocator specific components. The current allocators
1023 * rely on using both a size-ordered range_tree_t and an array of uint64_t's.
1026 metaslab_rt_create(range_tree_t
*rt
, void *arg
)
1028 metaslab_t
*msp
= arg
;
1030 ASSERT3P(rt
->rt_arg
, ==, msp
);
1031 ASSERT(msp
->ms_tree
== NULL
);
1033 avl_create(&msp
->ms_size_tree
, metaslab_rangesize_compare
,
1034 sizeof (range_seg_t
), offsetof(range_seg_t
, rs_pp_node
));
1038 * Destroy the block allocator specific components.
1041 metaslab_rt_destroy(range_tree_t
*rt
, void *arg
)
1043 metaslab_t
*msp
= arg
;
1045 ASSERT3P(rt
->rt_arg
, ==, msp
);
1046 ASSERT3P(msp
->ms_tree
, ==, rt
);
1047 ASSERT0(avl_numnodes(&msp
->ms_size_tree
));
1049 avl_destroy(&msp
->ms_size_tree
);
1053 metaslab_rt_add(range_tree_t
*rt
, range_seg_t
*rs
, void *arg
)
1055 metaslab_t
*msp
= arg
;
1057 ASSERT3P(rt
->rt_arg
, ==, msp
);
1058 ASSERT3P(msp
->ms_tree
, ==, rt
);
1059 VERIFY(!msp
->ms_condensing
);
1060 avl_add(&msp
->ms_size_tree
, rs
);
1064 metaslab_rt_remove(range_tree_t
*rt
, range_seg_t
*rs
, void *arg
)
1066 metaslab_t
*msp
= arg
;
1068 ASSERT3P(rt
->rt_arg
, ==, msp
);
1069 ASSERT3P(msp
->ms_tree
, ==, rt
);
1070 VERIFY(!msp
->ms_condensing
);
1071 avl_remove(&msp
->ms_size_tree
, rs
);
1075 metaslab_rt_vacate(range_tree_t
*rt
, void *arg
)
1077 metaslab_t
*msp
= arg
;
1079 ASSERT3P(rt
->rt_arg
, ==, msp
);
1080 ASSERT3P(msp
->ms_tree
, ==, rt
);
1083 * Normally one would walk the tree freeing nodes along the way.
1084 * Since the nodes are shared with the range trees we can avoid
1085 * walking all nodes and just reinitialize the avl tree. The nodes
1086 * will be freed by the range tree, so we don't want to free them here.
1088 avl_create(&msp
->ms_size_tree
, metaslab_rangesize_compare
,
1089 sizeof (range_seg_t
), offsetof(range_seg_t
, rs_pp_node
));
1092 static range_tree_ops_t metaslab_rt_ops
= {
1094 metaslab_rt_destroy
,
1101 * ==========================================================================
1102 * Common allocator routines
1103 * ==========================================================================
1107 * Return the maximum contiguous segment within the metaslab.
1110 metaslab_block_maxsize(metaslab_t
*msp
)
1112 avl_tree_t
*t
= &msp
->ms_size_tree
;
1115 if (t
== NULL
|| (rs
= avl_last(t
)) == NULL
)
1118 return (rs
->rs_end
- rs
->rs_start
);
1121 static range_seg_t
*
1122 metaslab_block_find(avl_tree_t
*t
, uint64_t start
, uint64_t size
)
1124 range_seg_t
*rs
, rsearch
;
1127 rsearch
.rs_start
= start
;
1128 rsearch
.rs_end
= start
+ size
;
1130 rs
= avl_find(t
, &rsearch
, &where
);
1132 rs
= avl_nearest(t
, where
, AVL_AFTER
);
1139 * This is a helper function that can be used by the allocator to find
1140 * a suitable block to allocate. This will search the specified AVL
1141 * tree looking for a block that matches the specified criteria.
1144 metaslab_block_picker(avl_tree_t
*t
, uint64_t *cursor
, uint64_t size
,
1147 range_seg_t
*rs
= metaslab_block_find(t
, *cursor
, size
);
1149 while (rs
!= NULL
) {
1150 uint64_t offset
= P2ROUNDUP(rs
->rs_start
, align
);
1152 if (offset
+ size
<= rs
->rs_end
) {
1153 *cursor
= offset
+ size
;
1156 rs
= AVL_NEXT(t
, rs
);
1160 * If we know we've searched the whole map (*cursor == 0), give up.
1161 * Otherwise, reset the cursor to the beginning and try again.
1167 return (metaslab_block_picker(t
, cursor
, size
, align
));
1171 * ==========================================================================
1172 * The first-fit block allocator
1173 * ==========================================================================
1176 metaslab_ff_alloc(metaslab_t
*msp
, uint64_t size
)
1179 * Find the largest power of 2 block size that evenly divides the
1180 * requested size. This is used to try to allocate blocks with similar
1181 * alignment from the same area of the metaslab (i.e. same cursor
1182 * bucket) but it does not guarantee that other allocations sizes
1183 * may exist in the same region.
1185 uint64_t align
= size
& -size
;
1186 uint64_t *cursor
= &msp
->ms_lbas
[highbit64(align
) - 1];
1187 avl_tree_t
*t
= &msp
->ms_tree
->rt_root
;
1189 return (metaslab_block_picker(t
, cursor
, size
, align
));
1192 static metaslab_ops_t metaslab_ff_ops
= {
1197 * ==========================================================================
1198 * Dynamic block allocator -
1199 * Uses the first fit allocation scheme until space get low and then
1200 * adjusts to a best fit allocation method. Uses metaslab_df_alloc_threshold
1201 * and metaslab_df_free_pct to determine when to switch the allocation scheme.
1202 * ==========================================================================
1205 metaslab_df_alloc(metaslab_t
*msp
, uint64_t size
)
1208 * Find the largest power of 2 block size that evenly divides the
1209 * requested size. This is used to try to allocate blocks with similar
1210 * alignment from the same area of the metaslab (i.e. same cursor
1211 * bucket) but it does not guarantee that other allocations sizes
1212 * may exist in the same region.
1214 uint64_t align
= size
& -size
;
1215 uint64_t *cursor
= &msp
->ms_lbas
[highbit64(align
) - 1];
1216 range_tree_t
*rt
= msp
->ms_tree
;
1217 avl_tree_t
*t
= &rt
->rt_root
;
1218 uint64_t max_size
= metaslab_block_maxsize(msp
);
1219 int free_pct
= range_tree_space(rt
) * 100 / msp
->ms_size
;
1221 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1222 ASSERT3U(avl_numnodes(t
), ==, avl_numnodes(&msp
->ms_size_tree
));
1224 if (max_size
< size
)
1228 * If we're running low on space switch to using the size
1229 * sorted AVL tree (best-fit).
1231 if (max_size
< metaslab_df_alloc_threshold
||
1232 free_pct
< metaslab_df_free_pct
) {
1233 t
= &msp
->ms_size_tree
;
1237 return (metaslab_block_picker(t
, cursor
, size
, 1ULL));
1240 static metaslab_ops_t metaslab_df_ops
= {
1245 * ==========================================================================
1246 * Cursor fit block allocator -
1247 * Select the largest region in the metaslab, set the cursor to the beginning
1248 * of the range and the cursor_end to the end of the range. As allocations
1249 * are made advance the cursor. Continue allocating from the cursor until
1250 * the range is exhausted and then find a new range.
1251 * ==========================================================================
1254 metaslab_cf_alloc(metaslab_t
*msp
, uint64_t size
)
1256 range_tree_t
*rt
= msp
->ms_tree
;
1257 avl_tree_t
*t
= &msp
->ms_size_tree
;
1258 uint64_t *cursor
= &msp
->ms_lbas
[0];
1259 uint64_t *cursor_end
= &msp
->ms_lbas
[1];
1260 uint64_t offset
= 0;
1262 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1263 ASSERT3U(avl_numnodes(t
), ==, avl_numnodes(&rt
->rt_root
));
1265 ASSERT3U(*cursor_end
, >=, *cursor
);
1267 if ((*cursor
+ size
) > *cursor_end
) {
1270 rs
= avl_last(&msp
->ms_size_tree
);
1271 if (rs
== NULL
|| (rs
->rs_end
- rs
->rs_start
) < size
)
1274 *cursor
= rs
->rs_start
;
1275 *cursor_end
= rs
->rs_end
;
1284 static metaslab_ops_t metaslab_cf_ops
= {
1289 * ==========================================================================
1290 * New dynamic fit allocator -
1291 * Select a region that is large enough to allocate 2^metaslab_ndf_clump_shift
1292 * contiguous blocks. If no region is found then just use the largest segment
1294 * ==========================================================================
1298 * Determines desired number of contiguous blocks (2^metaslab_ndf_clump_shift)
1299 * to request from the allocator.
1301 uint64_t metaslab_ndf_clump_shift
= 4;
1304 metaslab_ndf_alloc(metaslab_t
*msp
, uint64_t size
)
1306 avl_tree_t
*t
= &msp
->ms_tree
->rt_root
;
1308 range_seg_t
*rs
, rsearch
;
1309 uint64_t hbit
= highbit64(size
);
1310 uint64_t *cursor
= &msp
->ms_lbas
[hbit
- 1];
1311 uint64_t max_size
= metaslab_block_maxsize(msp
);
1313 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1314 ASSERT3U(avl_numnodes(t
), ==, avl_numnodes(&msp
->ms_size_tree
));
1316 if (max_size
< size
)
1319 rsearch
.rs_start
= *cursor
;
1320 rsearch
.rs_end
= *cursor
+ size
;
1322 rs
= avl_find(t
, &rsearch
, &where
);
1323 if (rs
== NULL
|| (rs
->rs_end
- rs
->rs_start
) < size
) {
1324 t
= &msp
->ms_size_tree
;
1326 rsearch
.rs_start
= 0;
1327 rsearch
.rs_end
= MIN(max_size
,
1328 1ULL << (hbit
+ metaslab_ndf_clump_shift
));
1329 rs
= avl_find(t
, &rsearch
, &where
);
1331 rs
= avl_nearest(t
, where
, AVL_AFTER
);
1335 if ((rs
->rs_end
- rs
->rs_start
) >= size
) {
1336 *cursor
= rs
->rs_start
+ size
;
1337 return (rs
->rs_start
);
1342 static metaslab_ops_t metaslab_ndf_ops
= {
1346 metaslab_ops_t
*zfs_metaslab_ops
= &metaslab_df_ops
;
1349 * ==========================================================================
1351 * ==========================================================================
1355 * Wait for any in-progress metaslab loads to complete.
1358 metaslab_load_wait(metaslab_t
*msp
)
1360 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1362 while (msp
->ms_loading
) {
1363 ASSERT(!msp
->ms_loaded
);
1364 cv_wait(&msp
->ms_load_cv
, &msp
->ms_lock
);
1369 metaslab_load(metaslab_t
*msp
)
1372 boolean_t success
= B_FALSE
;
1374 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1375 ASSERT(!msp
->ms_loaded
);
1376 ASSERT(!msp
->ms_loading
);
1378 msp
->ms_loading
= B_TRUE
;
1380 * Nobody else can manipulate a loading metaslab, so it's now safe
1381 * to drop the lock. This way we don't have to hold the lock while
1382 * reading the spacemap from disk.
1384 mutex_exit(&msp
->ms_lock
);
1387 * If the space map has not been allocated yet, then treat
1388 * all the space in the metaslab as free and add it to the
1391 if (msp
->ms_sm
!= NULL
)
1392 error
= space_map_load(msp
->ms_sm
, msp
->ms_tree
, SM_FREE
);
1394 range_tree_add(msp
->ms_tree
, msp
->ms_start
, msp
->ms_size
);
1396 success
= (error
== 0);
1398 mutex_enter(&msp
->ms_lock
);
1399 msp
->ms_loading
= B_FALSE
;
1402 ASSERT3P(msp
->ms_group
, !=, NULL
);
1403 msp
->ms_loaded
= B_TRUE
;
1405 for (int t
= 0; t
< TXG_DEFER_SIZE
; t
++) {
1406 range_tree_walk(msp
->ms_defertree
[t
],
1407 range_tree_remove
, msp
->ms_tree
);
1409 msp
->ms_max_size
= metaslab_block_maxsize(msp
);
1411 cv_broadcast(&msp
->ms_load_cv
);
1416 metaslab_unload(metaslab_t
*msp
)
1418 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1419 range_tree_vacate(msp
->ms_tree
, NULL
, NULL
);
1420 msp
->ms_loaded
= B_FALSE
;
1421 msp
->ms_weight
&= ~METASLAB_ACTIVE_MASK
;
1422 msp
->ms_max_size
= 0;
1426 metaslab_init(metaslab_group_t
*mg
, uint64_t id
, uint64_t object
, uint64_t txg
,
1429 vdev_t
*vd
= mg
->mg_vd
;
1430 objset_t
*mos
= vd
->vdev_spa
->spa_meta_objset
;
1434 ms
= kmem_zalloc(sizeof (metaslab_t
), KM_SLEEP
);
1435 mutex_init(&ms
->ms_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
1436 mutex_init(&ms
->ms_sync_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
1437 cv_init(&ms
->ms_load_cv
, NULL
, CV_DEFAULT
, NULL
);
1439 ms
->ms_start
= id
<< vd
->vdev_ms_shift
;
1440 ms
->ms_size
= 1ULL << vd
->vdev_ms_shift
;
1443 * We only open space map objects that already exist. All others
1444 * will be opened when we finally allocate an object for it.
1447 error
= space_map_open(&ms
->ms_sm
, mos
, object
, ms
->ms_start
,
1448 ms
->ms_size
, vd
->vdev_ashift
);
1451 kmem_free(ms
, sizeof (metaslab_t
));
1455 ASSERT(ms
->ms_sm
!= NULL
);
1459 * We create the main range tree here, but we don't create the
1460 * other range trees until metaslab_sync_done(). This serves
1461 * two purposes: it allows metaslab_sync_done() to detect the
1462 * addition of new space; and for debugging, it ensures that we'd
1463 * data fault on any attempt to use this metaslab before it's ready.
1465 ms
->ms_tree
= range_tree_create(&metaslab_rt_ops
, ms
);
1466 metaslab_group_add(mg
, ms
);
1468 metaslab_set_fragmentation(ms
);
1471 * If we're opening an existing pool (txg == 0) or creating
1472 * a new one (txg == TXG_INITIAL), all space is available now.
1473 * If we're adding space to an existing pool, the new space
1474 * does not become available until after this txg has synced.
1475 * The metaslab's weight will also be initialized when we sync
1476 * out this txg. This ensures that we don't attempt to allocate
1477 * from it before we have initialized it completely.
1479 if (txg
<= TXG_INITIAL
)
1480 metaslab_sync_done(ms
, 0);
1483 * If metaslab_debug_load is set and we're initializing a metaslab
1484 * that has an allocated space map object then load the its space
1485 * map so that can verify frees.
1487 if (metaslab_debug_load
&& ms
->ms_sm
!= NULL
) {
1488 mutex_enter(&ms
->ms_lock
);
1489 VERIFY0(metaslab_load(ms
));
1490 mutex_exit(&ms
->ms_lock
);
1494 vdev_dirty(vd
, 0, NULL
, txg
);
1495 vdev_dirty(vd
, VDD_METASLAB
, ms
, txg
);
1504 metaslab_fini(metaslab_t
*msp
)
1506 metaslab_group_t
*mg
= msp
->ms_group
;
1508 metaslab_group_remove(mg
, msp
);
1510 mutex_enter(&msp
->ms_lock
);
1511 VERIFY(msp
->ms_group
== NULL
);
1512 vdev_space_update(mg
->mg_vd
, -space_map_allocated(msp
->ms_sm
),
1514 space_map_close(msp
->ms_sm
);
1516 metaslab_unload(msp
);
1517 range_tree_destroy(msp
->ms_tree
);
1518 range_tree_destroy(msp
->ms_freeingtree
);
1519 range_tree_destroy(msp
->ms_freedtree
);
1521 for (int t
= 0; t
< TXG_SIZE
; t
++) {
1522 range_tree_destroy(msp
->ms_alloctree
[t
]);
1525 for (int t
= 0; t
< TXG_DEFER_SIZE
; t
++) {
1526 range_tree_destroy(msp
->ms_defertree
[t
]);
1529 ASSERT0(msp
->ms_deferspace
);
1531 mutex_exit(&msp
->ms_lock
);
1532 cv_destroy(&msp
->ms_load_cv
);
1533 mutex_destroy(&msp
->ms_lock
);
1534 mutex_destroy(&msp
->ms_sync_lock
);
1536 kmem_free(msp
, sizeof (metaslab_t
));
1539 #define FRAGMENTATION_TABLE_SIZE 17
1542 * This table defines a segment size based fragmentation metric that will
1543 * allow each metaslab to derive its own fragmentation value. This is done
1544 * by calculating the space in each bucket of the spacemap histogram and
1545 * multiplying that by the fragmetation metric in this table. Doing
1546 * this for all buckets and dividing it by the total amount of free
1547 * space in this metaslab (i.e. the total free space in all buckets) gives
1548 * us the fragmentation metric. This means that a high fragmentation metric
1549 * equates to most of the free space being comprised of small segments.
1550 * Conversely, if the metric is low, then most of the free space is in
1551 * large segments. A 10% change in fragmentation equates to approximately
1552 * double the number of segments.
1554 * This table defines 0% fragmented space using 16MB segments. Testing has
1555 * shown that segments that are greater than or equal to 16MB do not suffer
1556 * from drastic performance problems. Using this value, we derive the rest
1557 * of the table. Since the fragmentation value is never stored on disk, it
1558 * is possible to change these calculations in the future.
1560 int zfs_frag_table
[FRAGMENTATION_TABLE_SIZE
] = {
1580 * Calclate the metaslab's fragmentation metric. A return value
1581 * of ZFS_FRAG_INVALID means that the metaslab has not been upgraded and does
1582 * not support this metric. Otherwise, the return value should be in the
1586 metaslab_set_fragmentation(metaslab_t
*msp
)
1588 spa_t
*spa
= msp
->ms_group
->mg_vd
->vdev_spa
;
1589 uint64_t fragmentation
= 0;
1591 boolean_t feature_enabled
= spa_feature_is_enabled(spa
,
1592 SPA_FEATURE_SPACEMAP_HISTOGRAM
);
1594 if (!feature_enabled
) {
1595 msp
->ms_fragmentation
= ZFS_FRAG_INVALID
;
1600 * A null space map means that the entire metaslab is free
1601 * and thus is not fragmented.
1603 if (msp
->ms_sm
== NULL
) {
1604 msp
->ms_fragmentation
= 0;
1609 * If this metaslab's space map has not been upgraded, flag it
1610 * so that we upgrade next time we encounter it.
1612 if (msp
->ms_sm
->sm_dbuf
->db_size
!= sizeof (space_map_phys_t
)) {
1613 uint64_t txg
= spa_syncing_txg(spa
);
1614 vdev_t
*vd
= msp
->ms_group
->mg_vd
;
1617 * If we've reached the final dirty txg, then we must
1618 * be shutting down the pool. We don't want to dirty
1619 * any data past this point so skip setting the condense
1620 * flag. We can retry this action the next time the pool
1623 if (spa_writeable(spa
) && txg
< spa_final_dirty_txg(spa
)) {
1624 msp
->ms_condense_wanted
= B_TRUE
;
1625 vdev_dirty(vd
, VDD_METASLAB
, msp
, txg
+ 1);
1626 spa_dbgmsg(spa
, "txg %llu, requesting force condense: "
1627 "ms_id %llu, vdev_id %llu", txg
, msp
->ms_id
,
1630 msp
->ms_fragmentation
= ZFS_FRAG_INVALID
;
1634 for (int i
= 0; i
< SPACE_MAP_HISTOGRAM_SIZE
; i
++) {
1636 uint8_t shift
= msp
->ms_sm
->sm_shift
;
1638 int idx
= MIN(shift
- SPA_MINBLOCKSHIFT
+ i
,
1639 FRAGMENTATION_TABLE_SIZE
- 1);
1641 if (msp
->ms_sm
->sm_phys
->smp_histogram
[i
] == 0)
1644 space
= msp
->ms_sm
->sm_phys
->smp_histogram
[i
] << (i
+ shift
);
1647 ASSERT3U(idx
, <, FRAGMENTATION_TABLE_SIZE
);
1648 fragmentation
+= space
* zfs_frag_table
[idx
];
1652 fragmentation
/= total
;
1653 ASSERT3U(fragmentation
, <=, 100);
1655 msp
->ms_fragmentation
= fragmentation
;
1659 * Compute a weight -- a selection preference value -- for the given metaslab.
1660 * This is based on the amount of free space, the level of fragmentation,
1661 * the LBA range, and whether the metaslab is loaded.
1664 metaslab_space_weight(metaslab_t
*msp
)
1666 metaslab_group_t
*mg
= msp
->ms_group
;
1667 vdev_t
*vd
= mg
->mg_vd
;
1668 uint64_t weight
, space
;
1670 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1671 ASSERT(!vd
->vdev_removing
);
1674 * The baseline weight is the metaslab's free space.
1676 space
= msp
->ms_size
- space_map_allocated(msp
->ms_sm
);
1678 if (metaslab_fragmentation_factor_enabled
&&
1679 msp
->ms_fragmentation
!= ZFS_FRAG_INVALID
) {
1681 * Use the fragmentation information to inversely scale
1682 * down the baseline weight. We need to ensure that we
1683 * don't exclude this metaslab completely when it's 100%
1684 * fragmented. To avoid this we reduce the fragmented value
1687 space
= (space
* (100 - (msp
->ms_fragmentation
- 1))) / 100;
1690 * If space < SPA_MINBLOCKSIZE, then we will not allocate from
1691 * this metaslab again. The fragmentation metric may have
1692 * decreased the space to something smaller than
1693 * SPA_MINBLOCKSIZE, so reset the space to SPA_MINBLOCKSIZE
1694 * so that we can consume any remaining space.
1696 if (space
> 0 && space
< SPA_MINBLOCKSIZE
)
1697 space
= SPA_MINBLOCKSIZE
;
1702 * Modern disks have uniform bit density and constant angular velocity.
1703 * Therefore, the outer recording zones are faster (higher bandwidth)
1704 * than the inner zones by the ratio of outer to inner track diameter,
1705 * which is typically around 2:1. We account for this by assigning
1706 * higher weight to lower metaslabs (multiplier ranging from 2x to 1x).
1707 * In effect, this means that we'll select the metaslab with the most
1708 * free bandwidth rather than simply the one with the most free space.
1710 if (metaslab_lba_weighting_enabled
) {
1711 weight
= 2 * weight
- (msp
->ms_id
* weight
) / vd
->vdev_ms_count
;
1712 ASSERT(weight
>= space
&& weight
<= 2 * space
);
1716 * If this metaslab is one we're actively using, adjust its
1717 * weight to make it preferable to any inactive metaslab so
1718 * we'll polish it off. If the fragmentation on this metaslab
1719 * has exceed our threshold, then don't mark it active.
1721 if (msp
->ms_loaded
&& msp
->ms_fragmentation
!= ZFS_FRAG_INVALID
&&
1722 msp
->ms_fragmentation
<= zfs_metaslab_fragmentation_threshold
) {
1723 weight
|= (msp
->ms_weight
& METASLAB_ACTIVE_MASK
);
1726 WEIGHT_SET_SPACEBASED(weight
);
1731 * Return the weight of the specified metaslab, according to the segment-based
1732 * weighting algorithm. The metaslab must be loaded. This function can
1733 * be called within a sync pass since it relies only on the metaslab's
1734 * range tree which is always accurate when the metaslab is loaded.
1737 metaslab_weight_from_range_tree(metaslab_t
*msp
)
1739 uint64_t weight
= 0;
1740 uint32_t segments
= 0;
1742 ASSERT(msp
->ms_loaded
);
1744 for (int i
= RANGE_TREE_HISTOGRAM_SIZE
- 1; i
>= SPA_MINBLOCKSHIFT
;
1746 uint8_t shift
= msp
->ms_group
->mg_vd
->vdev_ashift
;
1747 int max_idx
= SPACE_MAP_HISTOGRAM_SIZE
+ shift
- 1;
1750 segments
+= msp
->ms_tree
->rt_histogram
[i
];
1753 * The range tree provides more precision than the space map
1754 * and must be downgraded so that all values fit within the
1755 * space map's histogram. This allows us to compare loaded
1756 * vs. unloaded metaslabs to determine which metaslab is
1757 * considered "best".
1762 if (segments
!= 0) {
1763 WEIGHT_SET_COUNT(weight
, segments
);
1764 WEIGHT_SET_INDEX(weight
, i
);
1765 WEIGHT_SET_ACTIVE(weight
, 0);
1773 * Calculate the weight based on the on-disk histogram. This should only
1774 * be called after a sync pass has completely finished since the on-disk
1775 * information is updated in metaslab_sync().
1778 metaslab_weight_from_spacemap(metaslab_t
*msp
)
1780 uint64_t weight
= 0;
1782 for (int i
= SPACE_MAP_HISTOGRAM_SIZE
- 1; i
>= 0; i
--) {
1783 if (msp
->ms_sm
->sm_phys
->smp_histogram
[i
] != 0) {
1784 WEIGHT_SET_COUNT(weight
,
1785 msp
->ms_sm
->sm_phys
->smp_histogram
[i
]);
1786 WEIGHT_SET_INDEX(weight
, i
+
1787 msp
->ms_sm
->sm_shift
);
1788 WEIGHT_SET_ACTIVE(weight
, 0);
1796 * Compute a segment-based weight for the specified metaslab. The weight
1797 * is determined by highest bucket in the histogram. The information
1798 * for the highest bucket is encoded into the weight value.
1801 metaslab_segment_weight(metaslab_t
*msp
)
1803 metaslab_group_t
*mg
= msp
->ms_group
;
1804 uint64_t weight
= 0;
1805 uint8_t shift
= mg
->mg_vd
->vdev_ashift
;
1807 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1810 * The metaslab is completely free.
1812 if (space_map_allocated(msp
->ms_sm
) == 0) {
1813 int idx
= highbit64(msp
->ms_size
) - 1;
1814 int max_idx
= SPACE_MAP_HISTOGRAM_SIZE
+ shift
- 1;
1816 if (idx
< max_idx
) {
1817 WEIGHT_SET_COUNT(weight
, 1ULL);
1818 WEIGHT_SET_INDEX(weight
, idx
);
1820 WEIGHT_SET_COUNT(weight
, 1ULL << (idx
- max_idx
));
1821 WEIGHT_SET_INDEX(weight
, max_idx
);
1823 WEIGHT_SET_ACTIVE(weight
, 0);
1824 ASSERT(!WEIGHT_IS_SPACEBASED(weight
));
1829 ASSERT3U(msp
->ms_sm
->sm_dbuf
->db_size
, ==, sizeof (space_map_phys_t
));
1832 * If the metaslab is fully allocated then just make the weight 0.
1834 if (space_map_allocated(msp
->ms_sm
) == msp
->ms_size
)
1837 * If the metaslab is already loaded, then use the range tree to
1838 * determine the weight. Otherwise, we rely on the space map information
1839 * to generate the weight.
1841 if (msp
->ms_loaded
) {
1842 weight
= metaslab_weight_from_range_tree(msp
);
1844 weight
= metaslab_weight_from_spacemap(msp
);
1848 * If the metaslab was active the last time we calculated its weight
1849 * then keep it active. We want to consume the entire region that
1850 * is associated with this weight.
1852 if (msp
->ms_activation_weight
!= 0 && weight
!= 0)
1853 WEIGHT_SET_ACTIVE(weight
, WEIGHT_GET_ACTIVE(msp
->ms_weight
));
1858 * Determine if we should attempt to allocate from this metaslab. If the
1859 * metaslab has a maximum size then we can quickly determine if the desired
1860 * allocation size can be satisfied. Otherwise, if we're using segment-based
1861 * weighting then we can determine the maximum allocation that this metaslab
1862 * can accommodate based on the index encoded in the weight. If we're using
1863 * space-based weights then rely on the entire weight (excluding the weight
1867 metaslab_should_allocate(metaslab_t
*msp
, uint64_t asize
)
1869 boolean_t should_allocate
;
1871 if (msp
->ms_max_size
!= 0)
1872 return (msp
->ms_max_size
>= asize
);
1874 if (!WEIGHT_IS_SPACEBASED(msp
->ms_weight
)) {
1876 * The metaslab segment weight indicates segments in the
1877 * range [2^i, 2^(i+1)), where i is the index in the weight.
1878 * Since the asize might be in the middle of the range, we
1879 * should attempt the allocation if asize < 2^(i+1).
1881 should_allocate
= (asize
<
1882 1ULL << (WEIGHT_GET_INDEX(msp
->ms_weight
) + 1));
1884 should_allocate
= (asize
<=
1885 (msp
->ms_weight
& ~METASLAB_WEIGHT_TYPE
));
1887 return (should_allocate
);
1891 metaslab_weight(metaslab_t
*msp
)
1893 vdev_t
*vd
= msp
->ms_group
->mg_vd
;
1894 spa_t
*spa
= vd
->vdev_spa
;
1897 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1900 * If this vdev is in the process of being removed, there is nothing
1901 * for us to do here.
1903 if (vd
->vdev_removing
)
1906 metaslab_set_fragmentation(msp
);
1909 * Update the maximum size if the metaslab is loaded. This will
1910 * ensure that we get an accurate maximum size if newly freed space
1911 * has been added back into the free tree.
1914 msp
->ms_max_size
= metaslab_block_maxsize(msp
);
1917 * Segment-based weighting requires space map histogram support.
1919 if (zfs_metaslab_segment_weight_enabled
&&
1920 spa_feature_is_enabled(spa
, SPA_FEATURE_SPACEMAP_HISTOGRAM
) &&
1921 (msp
->ms_sm
== NULL
|| msp
->ms_sm
->sm_dbuf
->db_size
==
1922 sizeof (space_map_phys_t
))) {
1923 weight
= metaslab_segment_weight(msp
);
1925 weight
= metaslab_space_weight(msp
);
1931 metaslab_activate(metaslab_t
*msp
, uint64_t activation_weight
)
1933 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
1935 if ((msp
->ms_weight
& METASLAB_ACTIVE_MASK
) == 0) {
1936 metaslab_load_wait(msp
);
1937 if (!msp
->ms_loaded
) {
1938 int error
= metaslab_load(msp
);
1940 metaslab_group_sort(msp
->ms_group
, msp
, 0);
1945 msp
->ms_activation_weight
= msp
->ms_weight
;
1946 metaslab_group_sort(msp
->ms_group
, msp
,
1947 msp
->ms_weight
| activation_weight
);
1949 ASSERT(msp
->ms_loaded
);
1950 ASSERT(msp
->ms_weight
& METASLAB_ACTIVE_MASK
);
1956 metaslab_passivate(metaslab_t
*msp
, uint64_t weight
)
1958 uint64_t size
= weight
& ~METASLAB_WEIGHT_TYPE
;
1961 * If size < SPA_MINBLOCKSIZE, then we will not allocate from
1962 * this metaslab again. In that case, it had better be empty,
1963 * or we would be leaving space on the table.
1965 ASSERT(size
>= SPA_MINBLOCKSIZE
||
1966 range_tree_space(msp
->ms_tree
) == 0);
1967 ASSERT0(weight
& METASLAB_ACTIVE_MASK
);
1969 msp
->ms_activation_weight
= 0;
1970 metaslab_group_sort(msp
->ms_group
, msp
, weight
);
1971 ASSERT((msp
->ms_weight
& METASLAB_ACTIVE_MASK
) == 0);
1975 * Segment-based metaslabs are activated once and remain active until
1976 * we either fail an allocation attempt (similar to space-based metaslabs)
1977 * or have exhausted the free space in zfs_metaslab_switch_threshold
1978 * buckets since the metaslab was activated. This function checks to see
1979 * if we've exhaused the zfs_metaslab_switch_threshold buckets in the
1980 * metaslab and passivates it proactively. This will allow us to select a
1981 * metaslabs with larger contiguous region if any remaining within this
1982 * metaslab group. If we're in sync pass > 1, then we continue using this
1983 * metaslab so that we don't dirty more block and cause more sync passes.
1986 metaslab_segment_may_passivate(metaslab_t
*msp
)
1988 spa_t
*spa
= msp
->ms_group
->mg_vd
->vdev_spa
;
1990 if (WEIGHT_IS_SPACEBASED(msp
->ms_weight
) || spa_sync_pass(spa
) > 1)
1994 * Since we are in the middle of a sync pass, the most accurate
1995 * information that is accessible to us is the in-core range tree
1996 * histogram; calculate the new weight based on that information.
1998 uint64_t weight
= metaslab_weight_from_range_tree(msp
);
1999 int activation_idx
= WEIGHT_GET_INDEX(msp
->ms_activation_weight
);
2000 int current_idx
= WEIGHT_GET_INDEX(weight
);
2002 if (current_idx
<= activation_idx
- zfs_metaslab_switch_threshold
)
2003 metaslab_passivate(msp
, weight
);
2007 metaslab_preload(void *arg
)
2009 metaslab_t
*msp
= arg
;
2010 spa_t
*spa
= msp
->ms_group
->mg_vd
->vdev_spa
;
2012 ASSERT(!MUTEX_HELD(&msp
->ms_group
->mg_lock
));
2014 mutex_enter(&msp
->ms_lock
);
2015 metaslab_load_wait(msp
);
2016 if (!msp
->ms_loaded
)
2017 (void) metaslab_load(msp
);
2018 msp
->ms_selected_txg
= spa_syncing_txg(spa
);
2019 mutex_exit(&msp
->ms_lock
);
2023 metaslab_group_preload(metaslab_group_t
*mg
)
2025 spa_t
*spa
= mg
->mg_vd
->vdev_spa
;
2027 avl_tree_t
*t
= &mg
->mg_metaslab_tree
;
2030 if (spa_shutting_down(spa
) || !metaslab_preload_enabled
) {
2031 taskq_wait(mg
->mg_taskq
);
2035 mutex_enter(&mg
->mg_lock
);
2038 * Load the next potential metaslabs
2040 for (msp
= avl_first(t
); msp
!= NULL
; msp
= AVL_NEXT(t
, msp
)) {
2041 ASSERT3P(msp
->ms_group
, ==, mg
);
2044 * We preload only the maximum number of metaslabs specified
2045 * by metaslab_preload_limit. If a metaslab is being forced
2046 * to condense then we preload it too. This will ensure
2047 * that force condensing happens in the next txg.
2049 if (++m
> metaslab_preload_limit
&& !msp
->ms_condense_wanted
) {
2053 VERIFY(taskq_dispatch(mg
->mg_taskq
, metaslab_preload
,
2054 msp
, TQ_SLEEP
) != NULL
);
2056 mutex_exit(&mg
->mg_lock
);
2060 * Determine if the space map's on-disk footprint is past our tolerance
2061 * for inefficiency. We would like to use the following criteria to make
2064 * 1. The size of the space map object should not dramatically increase as a
2065 * result of writing out the free space range tree.
2067 * 2. The minimal on-disk space map representation is zfs_condense_pct/100
2068 * times the size than the free space range tree representation
2069 * (i.e. zfs_condense_pct = 110 and in-core = 1MB, minimal = 1.1MB).
2071 * 3. The on-disk size of the space map should actually decrease.
2073 * Checking the first condition is tricky since we don't want to walk
2074 * the entire AVL tree calculating the estimated on-disk size. Instead we
2075 * use the size-ordered range tree in the metaslab and calculate the
2076 * size required to write out the largest segment in our free tree. If the
2077 * size required to represent that segment on disk is larger than the space
2078 * map object then we avoid condensing this map.
2080 * To determine the second criterion we use a best-case estimate and assume
2081 * each segment can be represented on-disk as a single 64-bit entry. We refer
2082 * to this best-case estimate as the space map's minimal form.
2084 * Unfortunately, we cannot compute the on-disk size of the space map in this
2085 * context because we cannot accurately compute the effects of compression, etc.
2086 * Instead, we apply the heuristic described in the block comment for
2087 * zfs_metaslab_condense_block_threshold - we only condense if the space used
2088 * is greater than a threshold number of blocks.
2091 metaslab_should_condense(metaslab_t
*msp
)
2093 space_map_t
*sm
= msp
->ms_sm
;
2095 uint64_t size
, entries
, segsz
, object_size
, optimal_size
, record_size
;
2096 dmu_object_info_t doi
;
2097 uint64_t vdev_blocksize
= 1 << msp
->ms_group
->mg_vd
->vdev_ashift
;
2099 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
2100 ASSERT(msp
->ms_loaded
);
2103 * Use the ms_size_tree range tree, which is ordered by size, to
2104 * obtain the largest segment in the free tree. We always condense
2105 * metaslabs that are empty and metaslabs for which a condense
2106 * request has been made.
2108 rs
= avl_last(&msp
->ms_size_tree
);
2109 if (rs
== NULL
|| msp
->ms_condense_wanted
)
2113 * Calculate the number of 64-bit entries this segment would
2114 * require when written to disk. If this single segment would be
2115 * larger on-disk than the entire current on-disk structure, then
2116 * clearly condensing will increase the on-disk structure size.
2118 size
= (rs
->rs_end
- rs
->rs_start
) >> sm
->sm_shift
;
2119 entries
= size
/ (MIN(size
, SM_RUN_MAX
));
2120 segsz
= entries
* sizeof (uint64_t);
2122 optimal_size
= sizeof (uint64_t) * avl_numnodes(&msp
->ms_tree
->rt_root
);
2123 object_size
= space_map_length(msp
->ms_sm
);
2125 dmu_object_info_from_db(sm
->sm_dbuf
, &doi
);
2126 record_size
= MAX(doi
.doi_data_block_size
, vdev_blocksize
);
2128 return (segsz
<= object_size
&&
2129 object_size
>= (optimal_size
* zfs_condense_pct
/ 100) &&
2130 object_size
> zfs_metaslab_condense_block_threshold
* record_size
);
2134 * Condense the on-disk space map representation to its minimized form.
2135 * The minimized form consists of a small number of allocations followed by
2136 * the entries of the free range tree.
2139 metaslab_condense(metaslab_t
*msp
, uint64_t txg
, dmu_tx_t
*tx
)
2141 spa_t
*spa
= msp
->ms_group
->mg_vd
->vdev_spa
;
2142 range_tree_t
*condense_tree
;
2143 space_map_t
*sm
= msp
->ms_sm
;
2145 ASSERT(MUTEX_HELD(&msp
->ms_lock
));
2146 ASSERT3U(spa_sync_pass(spa
), ==, 1);
2147 ASSERT(msp
->ms_loaded
);
2150 spa_dbgmsg(spa
, "condensing: txg %llu, msp[%llu] %p, vdev id %llu, "
2151 "spa %s, smp size %llu, segments %lu, forcing condense=%s", txg
,
2152 msp
->ms_id
, msp
, msp
->ms_group
->mg_vd
->vdev_id
,
2153 msp
->ms_group
->mg_vd
->vdev_spa
->spa_name
,
2154 space_map_length(msp
->ms_sm
), avl_numnodes(&msp
->ms_tree
->rt_root
),
2155 msp
->ms_condense_wanted
? "TRUE" : "FALSE");
2157 msp
->ms_condense_wanted
= B_FALSE
;
2160 * Create an range tree that is 100% allocated. We remove segments
2161 * that have been freed in this txg, any deferred frees that exist,
2162 * and any allocation in the future. Removing segments should be
2163 * a relatively inexpensive operation since we expect these trees to
2164 * have a small number of nodes.
2166 condense_tree
= range_tree_create(NULL
, NULL
);
2167 range_tree_add(condense_tree
, msp
->ms_start
, msp
->ms_size
);
2170 * Remove what's been freed in this txg from the condense_tree.
2171 * Since we're in sync_pass 1, we know that all the frees from
2172 * this txg are in the freeingtree.
2174 range_tree_walk(msp
->ms_freeingtree
, range_tree_remove
, condense_tree
);
2176 for (int t
= 0; t
< TXG_DEFER_SIZE
; t
++) {
2177 range_tree_walk(msp
->ms_defertree
[t
],
2178 range_tree_remove
, condense_tree
);
2181 for (int t
= 1; t
< TXG_CONCURRENT_STATES
; t
++) {
2182 range_tree_walk(msp
->ms_alloctree
[(txg
+ t
) & TXG_MASK
],
2183 range_tree_remove
, condense_tree
);
2187 * We're about to drop the metaslab's lock thus allowing
2188 * other consumers to change it's content. Set the
2189 * metaslab's ms_condensing flag to ensure that
2190 * allocations on this metaslab do not occur while we're
2191 * in the middle of committing it to disk. This is only critical
2192 * for the ms_tree as all other range trees use per txg
2193 * views of their content.
2195 msp
->ms_condensing
= B_TRUE
;
2197 mutex_exit(&msp
->ms_lock
);
2198 space_map_truncate(sm
, tx
);
2201 * While we would ideally like to create a space map representation
2202 * that consists only of allocation records, doing so can be
2203 * prohibitively expensive because the in-core free tree can be
2204 * large, and therefore computationally expensive to subtract
2205 * from the condense_tree. Instead we sync out two trees, a cheap
2206 * allocation only tree followed by the in-core free tree. While not
2207 * optimal, this is typically close to optimal, and much cheaper to
2210 space_map_write(sm
, condense_tree
, SM_ALLOC
, tx
);
2211 range_tree_vacate(condense_tree
, NULL
, NULL
);
2212 range_tree_destroy(condense_tree
);
2214 space_map_write(sm
, msp
->ms_tree
, SM_FREE
, tx
);
2215 mutex_enter(&msp
->ms_lock
);
2216 msp
->ms_condensing
= B_FALSE
;
2220 * Write a metaslab to disk in the context of the specified transaction group.
2223 metaslab_sync(metaslab_t
*msp
, uint64_t txg
)
2225 metaslab_group_t
*mg
= msp
->ms_group
;
2226 vdev_t
*vd
= mg
->mg_vd
;
2227 spa_t
*spa
= vd
->vdev_spa
;
2228 objset_t
*mos
= spa_meta_objset(spa
);
2229 range_tree_t
*alloctree
= msp
->ms_alloctree
[txg
& TXG_MASK
];
2231 uint64_t object
= space_map_object(msp
->ms_sm
);
2233 ASSERT(!vd
->vdev_ishole
);
2236 * This metaslab has just been added so there's no work to do now.
2238 if (msp
->ms_freeingtree
== NULL
) {
2239 ASSERT3P(alloctree
, ==, NULL
);
2243 ASSERT3P(alloctree
, !=, NULL
);
2244 ASSERT3P(msp
->ms_freeingtree
, !=, NULL
);
2245 ASSERT3P(msp
->ms_freedtree
, !=, NULL
);
2248 * Normally, we don't want to process a metaslab if there
2249 * are no allocations or frees to perform. However, if the metaslab
2250 * is being forced to condense and it's loaded, we need to let it
2253 if (range_tree_space(alloctree
) == 0 &&
2254 range_tree_space(msp
->ms_freeingtree
) == 0 &&
2255 !(msp
->ms_loaded
&& msp
->ms_condense_wanted
))
2259 VERIFY(txg
<= spa_final_dirty_txg(spa
));
2262 * The only state that can actually be changing concurrently with
2263 * metaslab_sync() is the metaslab's ms_tree. No other thread can
2264 * be modifying this txg's alloctree, freeingtree, freedtree, or
2265 * space_map_phys_t. We drop ms_lock whenever we could call
2266 * into the DMU, because the DMU can call down to us
2267 * (e.g. via zio_free()) at any time.
2269 * The spa_vdev_remove_thread() can be reading metaslab state
2270 * concurrently, and it is locked out by the ms_sync_lock. Note
2271 * that the ms_lock is insufficient for this, because it is dropped
2272 * by space_map_write().
2275 tx
= dmu_tx_create_assigned(spa_get_dsl(spa
), txg
);
2277 if (msp
->ms_sm
== NULL
) {
2278 uint64_t new_object
;
2280 new_object
= space_map_alloc(mos
, tx
);
2281 VERIFY3U(new_object
, !=, 0);
2283 VERIFY0(space_map_open(&msp
->ms_sm
, mos
, new_object
,
2284 msp
->ms_start
, msp
->ms_size
, vd
->vdev_ashift
));
2285 ASSERT(msp
->ms_sm
!= NULL
);
2288 mutex_enter(&msp
->ms_sync_lock
);
2289 mutex_enter(&msp
->ms_lock
);
2292 * Note: metaslab_condense() clears the space map's histogram.
2293 * Therefore we must verify and remove this histogram before
2296 metaslab_group_histogram_verify(mg
);
2297 metaslab_class_histogram_verify(mg
->mg_class
);
2298 metaslab_group_histogram_remove(mg
, msp
);
2300 if (msp
->ms_loaded
&& spa_sync_pass(spa
) == 1 &&
2301 metaslab_should_condense(msp
)) {
2302 metaslab_condense(msp
, txg
, tx
);
2304 mutex_exit(&msp
->ms_lock
);
2305 space_map_write(msp
->ms_sm
, alloctree
, SM_ALLOC
, tx
);
2306 space_map_write(msp
->ms_sm
, msp
->ms_freeingtree
, SM_FREE
, tx
);
2307 mutex_enter(&msp
->ms_lock
);
2310 if (msp
->ms_loaded
) {
2312 * When the space map is loaded, we have an accurate
2313 * histogram in the range tree. This gives us an opportunity
2314 * to bring the space map's histogram up-to-date so we clear
2315 * it first before updating it.
2317 space_map_histogram_clear(msp
->ms_sm
);
2318 space_map_histogram_add(msp
->ms_sm
, msp
->ms_tree
, tx
);
2321 * Since we've cleared the histogram we need to add back
2322 * any free space that has already been processed, plus
2323 * any deferred space. This allows the on-disk histogram
2324 * to accurately reflect all free space even if some space
2325 * is not yet available for allocation (i.e. deferred).
2327 space_map_histogram_add(msp
->ms_sm
, msp
->ms_freedtree
, tx
);
2330 * Add back any deferred free space that has not been
2331 * added back into the in-core free tree yet. This will
2332 * ensure that we don't end up with a space map histogram
2333 * that is completely empty unless the metaslab is fully
2336 for (int t
= 0; t
< TXG_DEFER_SIZE
; t
++) {
2337 space_map_histogram_add(msp
->ms_sm
,
2338 msp
->ms_defertree
[t
], tx
);
2343 * Always add the free space from this sync pass to the space
2344 * map histogram. We want to make sure that the on-disk histogram
2345 * accounts for all free space. If the space map is not loaded,
2346 * then we will lose some accuracy but will correct it the next
2347 * time we load the space map.
2349 space_map_histogram_add(msp
->ms_sm
, msp
->ms_freeingtree
, tx
);
2351 metaslab_group_histogram_add(mg
, msp
);
2352 metaslab_group_histogram_verify(mg
);
2353 metaslab_class_histogram_verify(mg
->mg_class
);
2356 * For sync pass 1, we avoid traversing this txg's free range tree
2357 * and instead will just swap the pointers for freeingtree and
2358 * freedtree. We can safely do this since the freed_tree is
2359 * guaranteed to be empty on the initial pass.
2361 if (spa_sync_pass(spa
) == 1) {
2362 range_tree_swap(&msp
->ms_freeingtree
, &msp
->ms_freedtree
);
2364 range_tree_vacate(msp
->ms_freeingtree
,
2365 range_tree_add
, msp
->ms_freedtree
);
2367 range_tree_vacate(alloctree
, NULL
, NULL
);
2369 ASSERT0(range_tree_space(msp
->ms_alloctree
[txg
& TXG_MASK
]));
2370 ASSERT0(range_tree_space(msp
->ms_alloctree
[TXG_CLEAN(txg
) & TXG_MASK
]));
2371 ASSERT0(range_tree_space(msp
->ms_freeingtree
));
2373 mutex_exit(&msp
->ms_lock
);
2375 if (object
!= space_map_object(msp
->ms_sm
)) {
2376 object
= space_map_object(msp
->ms_sm
);
2377 dmu_write(mos
, vd
->vdev_ms_array
, sizeof (uint64_t) *
2378 msp
->ms_id
, sizeof (uint64_t), &object
, tx
);
2380 mutex_exit(&msp
->ms_sync_lock
);
2385 * Called after a transaction group has completely synced to mark
2386 * all of the metaslab's free space as usable.
2389 metaslab_sync_done(metaslab_t
*msp
, uint64_t txg
)
2391 metaslab_group_t
*mg
= msp
->ms_group
;
2392 vdev_t
*vd
= mg
->mg_vd
;
2393 spa_t
*spa
= vd
->vdev_spa
;
2394 range_tree_t
**defer_tree
;
2395 int64_t alloc_delta
, defer_delta
;
2396 boolean_t defer_allowed
= B_TRUE
;
2398 ASSERT(!vd
->vdev_ishole
);
2400 mutex_enter(&msp
->ms_lock
);
2403 * If this metaslab is just becoming available, initialize its
2404 * range trees and add its capacity to the vdev.
2406 if (msp
->ms_freedtree
== NULL
) {
2407 for (int t
= 0; t
< TXG_SIZE
; t
++) {
2408 ASSERT(msp
->ms_alloctree
[t
] == NULL
);
2410 msp
->ms_alloctree
[t
] = range_tree_create(NULL
, NULL
);
2413 ASSERT3P(msp
->ms_freeingtree
, ==, NULL
);
2414 msp
->ms_freeingtree
= range_tree_create(NULL
, NULL
);
2416 ASSERT3P(msp
->ms_freedtree
, ==, NULL
);
2417 msp
->ms_freedtree
= range_tree_create(NULL
, NULL
);
2419 for (int t
= 0; t
< TXG_DEFER_SIZE
; t
++) {
2420 ASSERT(msp
->ms_defertree
[t
] == NULL
);
2422 msp
->ms_defertree
[t
] = range_tree_create(NULL
, NULL
);
2425 vdev_space_update(vd
, 0, 0, msp
->ms_size
);
2428 defer_tree
= &msp
->ms_defertree
[txg
% TXG_DEFER_SIZE
];
2430 uint64_t free_space
= metaslab_class_get_space(spa_normal_class(spa
)) -
2431 metaslab_class_get_alloc(spa_normal_class(spa
));
2432 if (free_space
<= spa_get_slop_space(spa
) || vd
->vdev_removing
) {
2433 defer_allowed
= B_FALSE
;
2437 alloc_delta
= space_map_alloc_delta(msp
->ms_sm
);
2438 if (defer_allowed
) {
2439 defer_delta
= range_tree_space(msp
->ms_freedtree
) -
2440 range_tree_space(*defer_tree
);
2442 defer_delta
-= range_tree_space(*defer_tree
);
2445 vdev_space_update(vd
, alloc_delta
+ defer_delta
, defer_delta
, 0);
2448 * If there's a metaslab_load() in progress, wait for it to complete
2449 * so that we have a consistent view of the in-core space map.
2451 metaslab_load_wait(msp
);
2454 * Move the frees from the defer_tree back to the free
2455 * range tree (if it's loaded). Swap the freed_tree and the
2456 * defer_tree -- this is safe to do because we've just emptied out
2459 range_tree_vacate(*defer_tree
,
2460 msp
->ms_loaded
? range_tree_add
: NULL
, msp
->ms_tree
);
2461 if (defer_allowed
) {
2462 range_tree_swap(&msp
->ms_freedtree
, defer_tree
);
2464 range_tree_vacate(msp
->ms_freedtree
,
2465 msp
->ms_loaded
? range_tree_add
: NULL
, msp
->ms_tree
);
2468 space_map_update(msp
->ms_sm
);
2470 msp
->ms_deferspace
+= defer_delta
;
2471 ASSERT3S(msp
->ms_deferspace
, >=, 0);
2472 ASSERT3S(msp
->ms_deferspace
, <=, msp
->ms_size
);
2473 if (msp
->ms_deferspace
!= 0) {
2475 * Keep syncing this metaslab until all deferred frees
2476 * are back in circulation.
2478 vdev_dirty(vd
, VDD_METASLAB
, msp
, txg
+ 1);
2482 * Calculate the new weights before unloading any metaslabs.
2483 * This will give us the most accurate weighting.
2485 metaslab_group_sort(mg
, msp
, metaslab_weight(msp
));
2488 * If the metaslab is loaded and we've not tried to load or allocate
2489 * from it in 'metaslab_unload_delay' txgs, then unload it.
2491 if (msp
->ms_loaded
&&
2492 msp
->ms_selected_txg
+ metaslab_unload_delay
< txg
) {
2493 for (int t
= 1; t
< TXG_CONCURRENT_STATES
; t
++) {
2494 VERIFY0(range_tree_space(
2495 msp
->ms_alloctree
[(txg
+ t
) & TXG_MASK
]));
2498 if (!metaslab_debug_unload
)
2499 metaslab_unload(msp
);
2502 ASSERT0(range_tree_space(msp
->ms_alloctree
[txg
& TXG_MASK
]));
2503 ASSERT0(range_tree_space(msp
->ms_freeingtree
));
2504 ASSERT0(range_tree_space(msp
->ms_freedtree
));
2506 mutex_exit(&msp
->ms_lock
);
2510 metaslab_sync_reassess(metaslab_group_t
*mg
)
2512 spa_t
*spa
= mg
->mg_class
->mc_spa
;
2514 spa_config_enter(spa
, SCL_ALLOC
, FTAG
, RW_READER
);
2515 metaslab_group_alloc_update(mg
);
2516 mg
->mg_fragmentation
= metaslab_group_fragmentation(mg
);
2519 * Preload the next potential metaslabs but only on active
2520 * metaslab groups. We can get into a state where the metaslab
2521 * is no longer active since we dirty metaslabs as we remove a
2522 * a device, thus potentially making the metaslab group eligible
2525 if (mg
->mg_activation_count
> 0) {
2526 metaslab_group_preload(mg
);
2528 spa_config_exit(spa
, SCL_ALLOC
, FTAG
);
2532 metaslab_distance(metaslab_t
*msp
, dva_t
*dva
)
2534 uint64_t ms_shift
= msp
->ms_group
->mg_vd
->vdev_ms_shift
;
2535 uint64_t offset
= DVA_GET_OFFSET(dva
) >> ms_shift
;
2536 uint64_t start
= msp
->ms_id
;
2538 if (msp
->ms_group
->mg_vd
->vdev_id
!= DVA_GET_VDEV(dva
))
2539 return (1ULL << 63);
2542 return ((start
- offset
) << ms_shift
);
2544 return ((offset
- start
) << ms_shift
);
2549 * ==========================================================================
2550 * Metaslab allocation tracing facility
2551 * ==========================================================================
2553 kstat_t
*metaslab_trace_ksp
;
2554 kstat_named_t metaslab_trace_over_limit
;
2557 metaslab_alloc_trace_init(void)
2559 ASSERT(metaslab_alloc_trace_cache
== NULL
);
2560 metaslab_alloc_trace_cache
= kmem_cache_create(
2561 "metaslab_alloc_trace_cache", sizeof (metaslab_alloc_trace_t
),
2562 0, NULL
, NULL
, NULL
, NULL
, NULL
, 0);
2563 metaslab_trace_ksp
= kstat_create("zfs", 0, "metaslab_trace_stats",
2564 "misc", KSTAT_TYPE_NAMED
, 1, KSTAT_FLAG_VIRTUAL
);
2565 if (metaslab_trace_ksp
!= NULL
) {
2566 metaslab_trace_ksp
->ks_data
= &metaslab_trace_over_limit
;
2567 kstat_named_init(&metaslab_trace_over_limit
,
2568 "metaslab_trace_over_limit", KSTAT_DATA_UINT64
);
2569 kstat_install(metaslab_trace_ksp
);
2574 metaslab_alloc_trace_fini(void)
2576 if (metaslab_trace_ksp
!= NULL
) {
2577 kstat_delete(metaslab_trace_ksp
);
2578 metaslab_trace_ksp
= NULL
;
2580 kmem_cache_destroy(metaslab_alloc_trace_cache
);
2581 metaslab_alloc_trace_cache
= NULL
;
2585 * Add an allocation trace element to the allocation tracing list.
2588 metaslab_trace_add(zio_alloc_list_t
*zal
, metaslab_group_t
*mg
,
2589 metaslab_t
*msp
, uint64_t psize
, uint32_t dva_id
, uint64_t offset
)
2591 if (!metaslab_trace_enabled
)
2595 * When the tracing list reaches its maximum we remove
2596 * the second element in the list before adding a new one.
2597 * By removing the second element we preserve the original
2598 * entry as a clue to what allocations steps have already been
2601 if (zal
->zal_size
== metaslab_trace_max_entries
) {
2602 metaslab_alloc_trace_t
*mat_next
;
2604 panic("too many entries in allocation list");
2606 atomic_inc_64(&metaslab_trace_over_limit
.value
.ui64
);
2608 mat_next
= list_next(&zal
->zal_list
, list_head(&zal
->zal_list
));
2609 list_remove(&zal
->zal_list
, mat_next
);
2610 kmem_cache_free(metaslab_alloc_trace_cache
, mat_next
);
2613 metaslab_alloc_trace_t
*mat
=
2614 kmem_cache_alloc(metaslab_alloc_trace_cache
, KM_SLEEP
);
2615 list_link_init(&mat
->mat_list_node
);
2618 mat
->mat_size
= psize
;
2619 mat
->mat_dva_id
= dva_id
;
2620 mat
->mat_offset
= offset
;
2621 mat
->mat_weight
= 0;
2624 mat
->mat_weight
= msp
->ms_weight
;
2627 * The list is part of the zio so locking is not required. Only
2628 * a single thread will perform allocations for a given zio.
2630 list_insert_tail(&zal
->zal_list
, mat
);
2633 ASSERT3U(zal
->zal_size
, <=, metaslab_trace_max_entries
);
2637 metaslab_trace_init(zio_alloc_list_t
*zal
)
2639 list_create(&zal
->zal_list
, sizeof (metaslab_alloc_trace_t
),
2640 offsetof(metaslab_alloc_trace_t
, mat_list_node
));
2645 metaslab_trace_fini(zio_alloc_list_t
*zal
)
2647 metaslab_alloc_trace_t
*mat
;
2649 while ((mat
= list_remove_head(&zal
->zal_list
)) != NULL
)
2650 kmem_cache_free(metaslab_alloc_trace_cache
, mat
);
2651 list_destroy(&zal
->zal_list
);
2656 * ==========================================================================
2657 * Metaslab block operations
2658 * ==========================================================================
2662 metaslab_group_alloc_increment(spa_t
*spa
, uint64_t vdev
, void *tag
, int flags
)
2664 if (!(flags
& METASLAB_ASYNC_ALLOC
) ||
2665 flags
& METASLAB_DONT_THROTTLE
)
2668 metaslab_group_t
*mg
= vdev_lookup_top(spa
, vdev
)->vdev_mg
;
2669 if (!mg
->mg_class
->mc_alloc_throttle_enabled
)
2672 (void) refcount_add(&mg
->mg_alloc_queue_depth
, tag
);
2676 metaslab_group_alloc_decrement(spa_t
*spa
, uint64_t vdev
, void *tag
, int flags
)
2678 if (!(flags
& METASLAB_ASYNC_ALLOC
) ||
2679 flags
& METASLAB_DONT_THROTTLE
)
2682 metaslab_group_t
*mg
= vdev_lookup_top(spa
, vdev
)->vdev_mg
;
2683 if (!mg
->mg_class
->mc_alloc_throttle_enabled
)
2686 (void) refcount_remove(&mg
->mg_alloc_queue_depth
, tag
);
2690 metaslab_group_alloc_verify(spa_t
*spa
, const blkptr_t
*bp
, void *tag
)
2693 const dva_t
*dva
= bp
->blk_dva
;
2694 int ndvas
= BP_GET_NDVAS(bp
);
2696 for (int d
= 0; d
< ndvas
; d
++) {
2697 uint64_t vdev
= DVA_GET_VDEV(&dva
[d
]);
2698 metaslab_group_t
*mg
= vdev_lookup_top(spa
, vdev
)->vdev_mg
;
2699 VERIFY(refcount_not_held(&mg
->mg_alloc_queue_depth
, tag
));
2705 metaslab_block_alloc(metaslab_t
*msp
, uint64_t size
, uint64_t txg
)
2708 range_tree_t
*rt
= msp
->ms_tree
;
2709 metaslab_class_t
*mc
= msp
->ms_group
->mg_class
;
2711 VERIFY(!msp
->ms_condensing
);
2713 start
= mc
->mc_ops
->msop_alloc(msp
, size
);
2714 if (start
!= -1ULL) {
2715 metaslab_group_t
*mg
= msp
->ms_group
;
2716 vdev_t
*vd
= mg
->mg_vd
;
2718 VERIFY0(P2PHASE(start
, 1ULL << vd
->vdev_ashift
));
2719 VERIFY0(P2PHASE(size
, 1ULL << vd
->vdev_ashift
));
2720 VERIFY3U(range_tree_space(rt
) - size
, <=, msp
->ms_size
);
2721 range_tree_remove(rt
, start
, size
);
2723 if (range_tree_space(msp
->ms_alloctree
[txg
& TXG_MASK
]) == 0)
2724 vdev_dirty(mg
->mg_vd
, VDD_METASLAB
, msp
, txg
);
2726 range_tree_add(msp
->ms_alloctree
[txg
& TXG_MASK
], start
, size
);
2728 /* Track the last successful allocation */
2729 msp
->ms_alloc_txg
= txg
;
2730 metaslab_verify_space(msp
, txg
);
2734 * Now that we've attempted the allocation we need to update the
2735 * metaslab's maximum block size since it may have changed.
2737 msp
->ms_max_size
= metaslab_block_maxsize(msp
);
2742 metaslab_group_alloc_normal(metaslab_group_t
*mg
, zio_alloc_list_t
*zal
,
2743 uint64_t asize
, uint64_t txg
, uint64_t min_distance
, dva_t
*dva
, int d
)
2745 metaslab_t
*msp
= NULL
;
2746 uint64_t offset
= -1ULL;
2747 uint64_t activation_weight
;
2748 uint64_t target_distance
;
2751 activation_weight
= METASLAB_WEIGHT_PRIMARY
;
2752 for (i
= 0; i
< d
; i
++) {
2753 if (DVA_GET_VDEV(&dva
[i
]) == mg
->mg_vd
->vdev_id
) {
2754 activation_weight
= METASLAB_WEIGHT_SECONDARY
;
2759 metaslab_t
*search
= kmem_alloc(sizeof (*search
), KM_SLEEP
);
2760 search
->ms_weight
= UINT64_MAX
;
2761 search
->ms_start
= 0;
2763 boolean_t was_active
;
2764 avl_tree_t
*t
= &mg
->mg_metaslab_tree
;
2767 mutex_enter(&mg
->mg_lock
);
2770 * Find the metaslab with the highest weight that is less
2771 * than what we've already tried. In the common case, this
2772 * means that we will examine each metaslab at most once.
2773 * Note that concurrent callers could reorder metaslabs
2774 * by activation/passivation once we have dropped the mg_lock.
2775 * If a metaslab is activated by another thread, and we fail
2776 * to allocate from the metaslab we have selected, we may
2777 * not try the newly-activated metaslab, and instead activate
2778 * another metaslab. This is not optimal, but generally
2779 * does not cause any problems (a possible exception being
2780 * if every metaslab is completely full except for the
2781 * the newly-activated metaslab which we fail to examine).
2783 msp
= avl_find(t
, search
, &idx
);
2785 msp
= avl_nearest(t
, idx
, AVL_AFTER
);
2786 for (; msp
!= NULL
; msp
= AVL_NEXT(t
, msp
)) {
2788 if (!metaslab_should_allocate(msp
, asize
)) {
2789 metaslab_trace_add(zal
, mg
, msp
, asize
, d
,
2795 * If the selected metaslab is condensing, skip it.
2797 if (msp
->ms_condensing
)
2800 was_active
= msp
->ms_weight
& METASLAB_ACTIVE_MASK
;
2801 if (activation_weight
== METASLAB_WEIGHT_PRIMARY
)
2804 target_distance
= min_distance
+
2805 (space_map_allocated(msp
->ms_sm
) != 0 ? 0 :
2808 for (i
= 0; i
< d
; i
++) {
2809 if (metaslab_distance(msp
, &dva
[i
]) <
2816 mutex_exit(&mg
->mg_lock
);
2818 kmem_free(search
, sizeof (*search
));
2821 search
->ms_weight
= msp
->ms_weight
;
2822 search
->ms_start
= msp
->ms_start
+ 1;
2824 mutex_enter(&msp
->ms_lock
);
2827 * Ensure that the metaslab we have selected is still
2828 * capable of handling our request. It's possible that
2829 * another thread may have changed the weight while we
2830 * were blocked on the metaslab lock. We check the
2831 * active status first to see if we need to reselect
2834 if (was_active
&& !(msp
->ms_weight
& METASLAB_ACTIVE_MASK
)) {
2835 mutex_exit(&msp
->ms_lock
);
2839 if ((msp
->ms_weight
& METASLAB_WEIGHT_SECONDARY
) &&
2840 activation_weight
== METASLAB_WEIGHT_PRIMARY
) {
2841 metaslab_passivate(msp
,
2842 msp
->ms_weight
& ~METASLAB_ACTIVE_MASK
);
2843 mutex_exit(&msp
->ms_lock
);
2847 if (metaslab_activate(msp
, activation_weight
) != 0) {
2848 mutex_exit(&msp
->ms_lock
);
2851 msp
->ms_selected_txg
= txg
;
2854 * Now that we have the lock, recheck to see if we should
2855 * continue to use this metaslab for this allocation. The
2856 * the metaslab is now loaded so metaslab_should_allocate() can
2857 * accurately determine if the allocation attempt should
2860 if (!metaslab_should_allocate(msp
, asize
)) {
2861 /* Passivate this metaslab and select a new one. */
2862 metaslab_trace_add(zal
, mg
, msp
, asize
, d
,
2868 * If this metaslab is currently condensing then pick again as
2869 * we can't manipulate this metaslab until it's committed
2872 if (msp
->ms_condensing
) {
2873 metaslab_trace_add(zal
, mg
, msp
, asize
, d
,
2875 mutex_exit(&msp
->ms_lock
);
2879 offset
= metaslab_block_alloc(msp
, asize
, txg
);
2880 metaslab_trace_add(zal
, mg
, msp
, asize
, d
, offset
);
2882 if (offset
!= -1ULL) {
2883 /* Proactively passivate the metaslab, if needed */
2884 metaslab_segment_may_passivate(msp
);
2888 ASSERT(msp
->ms_loaded
);
2891 * We were unable to allocate from this metaslab so determine
2892 * a new weight for this metaslab. Now that we have loaded
2893 * the metaslab we can provide a better hint to the metaslab
2896 * For space-based metaslabs, we use the maximum block size.
2897 * This information is only available when the metaslab
2898 * is loaded and is more accurate than the generic free
2899 * space weight that was calculated by metaslab_weight().
2900 * This information allows us to quickly compare the maximum
2901 * available allocation in the metaslab to the allocation
2902 * size being requested.
2904 * For segment-based metaslabs, determine the new weight
2905 * based on the highest bucket in the range tree. We
2906 * explicitly use the loaded segment weight (i.e. the range
2907 * tree histogram) since it contains the space that is
2908 * currently available for allocation and is accurate
2909 * even within a sync pass.
2911 if (WEIGHT_IS_SPACEBASED(msp
->ms_weight
)) {
2912 uint64_t weight
= metaslab_block_maxsize(msp
);
2913 WEIGHT_SET_SPACEBASED(weight
);
2914 metaslab_passivate(msp
, weight
);
2916 metaslab_passivate(msp
,
2917 metaslab_weight_from_range_tree(msp
));
2921 * We have just failed an allocation attempt, check
2922 * that metaslab_should_allocate() agrees. Otherwise,
2923 * we may end up in an infinite loop retrying the same
2926 ASSERT(!metaslab_should_allocate(msp
, asize
));
2927 mutex_exit(&msp
->ms_lock
);
2929 mutex_exit(&msp
->ms_lock
);
2930 kmem_free(search
, sizeof (*search
));
2935 metaslab_group_alloc(metaslab_group_t
*mg
, zio_alloc_list_t
*zal
,
2936 uint64_t asize
, uint64_t txg
, uint64_t min_distance
, dva_t
*dva
, int d
)
2939 ASSERT(mg
->mg_initialized
);
2941 offset
= metaslab_group_alloc_normal(mg
, zal
, asize
, txg
,
2942 min_distance
, dva
, d
);
2944 mutex_enter(&mg
->mg_lock
);
2945 if (offset
== -1ULL) {
2946 mg
->mg_failed_allocations
++;
2947 metaslab_trace_add(zal
, mg
, NULL
, asize
, d
,
2948 TRACE_GROUP_FAILURE
);
2949 if (asize
== SPA_GANGBLOCKSIZE
) {
2951 * This metaslab group was unable to allocate
2952 * the minimum gang block size so it must be out of
2953 * space. We must notify the allocation throttle
2954 * to start skipping allocation attempts to this
2955 * metaslab group until more space becomes available.
2956 * Note: this failure cannot be caused by the
2957 * allocation throttle since the allocation throttle
2958 * is only responsible for skipping devices and
2959 * not failing block allocations.
2961 mg
->mg_no_free_space
= B_TRUE
;
2964 mg
->mg_allocations
++;
2965 mutex_exit(&mg
->mg_lock
);
2970 * If we have to write a ditto block (i.e. more than one DVA for a given BP)
2971 * on the same vdev as an existing DVA of this BP, then try to allocate it
2972 * at least (vdev_asize / (2 ^ ditto_same_vdev_distance_shift)) away from the
2975 int ditto_same_vdev_distance_shift
= 3;
2978 * Allocate a block for the specified i/o.
2981 metaslab_alloc_dva(spa_t
*spa
, metaslab_class_t
*mc
, uint64_t psize
,
2982 dva_t
*dva
, int d
, dva_t
*hintdva
, uint64_t txg
, int flags
,
2983 zio_alloc_list_t
*zal
)
2985 metaslab_group_t
*mg
, *rotor
;
2987 boolean_t try_hard
= B_FALSE
;
2989 ASSERT(!DVA_IS_VALID(&dva
[d
]));
2992 * For testing, make some blocks above a certain size be gang blocks.
2994 if (psize
>= metaslab_gang_bang
&& (ddi_get_lbolt() & 3) == 0) {
2995 metaslab_trace_add(zal
, NULL
, NULL
, psize
, d
, TRACE_FORCE_GANG
);
2996 return (SET_ERROR(ENOSPC
));
3000 * Start at the rotor and loop through all mgs until we find something.
3001 * Note that there's no locking on mc_rotor or mc_aliquot because
3002 * nothing actually breaks if we miss a few updates -- we just won't
3003 * allocate quite as evenly. It all balances out over time.
3005 * If we are doing ditto or log blocks, try to spread them across
3006 * consecutive vdevs. If we're forced to reuse a vdev before we've
3007 * allocated all of our ditto blocks, then try and spread them out on
3008 * that vdev as much as possible. If it turns out to not be possible,
3009 * gradually lower our standards until anything becomes acceptable.
3010 * Also, allocating on consecutive vdevs (as opposed to random vdevs)
3011 * gives us hope of containing our fault domains to something we're
3012 * able to reason about. Otherwise, any two top-level vdev failures
3013 * will guarantee the loss of data. With consecutive allocation,
3014 * only two adjacent top-level vdev failures will result in data loss.
3016 * If we are doing gang blocks (hintdva is non-NULL), try to keep
3017 * ourselves on the same vdev as our gang block header. That
3018 * way, we can hope for locality in vdev_cache, plus it makes our
3019 * fault domains something tractable.
3022 vd
= vdev_lookup_top(spa
, DVA_GET_VDEV(&hintdva
[d
]));
3025 * It's possible the vdev we're using as the hint no
3026 * longer exists or its mg has been closed (e.g. by
3027 * device removal). Consult the rotor when
3030 if (vd
!= NULL
&& vd
->vdev_mg
!= NULL
) {
3033 if (flags
& METASLAB_HINTBP_AVOID
&&
3034 mg
->mg_next
!= NULL
)
3039 } else if (d
!= 0) {
3040 vd
= vdev_lookup_top(spa
, DVA_GET_VDEV(&dva
[d
- 1]));
3041 mg
= vd
->vdev_mg
->mg_next
;
3047 * If the hint put us into the wrong metaslab class, or into a
3048 * metaslab group that has been passivated, just follow the rotor.
3050 if (mg
->mg_class
!= mc
|| mg
->mg_activation_count
<= 0)
3056 boolean_t allocatable
;
3058 ASSERT(mg
->mg_activation_count
== 1);
3062 * Don't allocate from faulted devices.
3065 spa_config_enter(spa
, SCL_ZIO
, FTAG
, RW_READER
);
3066 allocatable
= vdev_allocatable(vd
);
3067 spa_config_exit(spa
, SCL_ZIO
, FTAG
);
3069 allocatable
= vdev_allocatable(vd
);
3073 * Determine if the selected metaslab group is eligible
3074 * for allocations. If we're ganging then don't allow
3075 * this metaslab group to skip allocations since that would
3076 * inadvertently return ENOSPC and suspend the pool
3077 * even though space is still available.
3079 if (allocatable
&& !GANG_ALLOCATION(flags
) && !try_hard
) {
3080 allocatable
= metaslab_group_allocatable(mg
, rotor
,
3085 metaslab_trace_add(zal
, mg
, NULL
, psize
, d
,
3086 TRACE_NOT_ALLOCATABLE
);
3090 ASSERT(mg
->mg_initialized
);
3093 * Avoid writing single-copy data to a failing,
3094 * non-redundant vdev, unless we've already tried all
3097 if ((vd
->vdev_stat
.vs_write_errors
> 0 ||
3098 vd
->vdev_state
< VDEV_STATE_HEALTHY
) &&
3099 d
== 0 && !try_hard
&& vd
->vdev_children
== 0) {
3100 metaslab_trace_add(zal
, mg
, NULL
, psize
, d
,
3105 ASSERT(mg
->mg_class
== mc
);
3108 * If we don't need to try hard, then require that the
3109 * block be 1/8th of the device away from any other DVAs
3110 * in this BP. If we are trying hard, allow any offset
3111 * to be used (distance=0).
3113 uint64_t distance
= 0;
3115 distance
= vd
->vdev_asize
>>
3116 ditto_same_vdev_distance_shift
;
3117 if (distance
<= (1ULL << vd
->vdev_ms_shift
))
3121 uint64_t asize
= vdev_psize_to_asize(vd
, psize
);
3122 ASSERT(P2PHASE(asize
, 1ULL << vd
->vdev_ashift
) == 0);
3124 uint64_t offset
= metaslab_group_alloc(mg
, zal
, asize
, txg
,
3127 if (offset
!= -1ULL) {
3129 * If we've just selected this metaslab group,
3130 * figure out whether the corresponding vdev is
3131 * over- or under-used relative to the pool,
3132 * and set an allocation bias to even it out.
3134 if (mc
->mc_aliquot
== 0 && metaslab_bias_enabled
) {
3135 vdev_stat_t
*vs
= &vd
->vdev_stat
;
3138 vu
= (vs
->vs_alloc
* 100) / (vs
->vs_space
+ 1);
3139 cu
= (mc
->mc_alloc
* 100) / (mc
->mc_space
+ 1);
3142 * Calculate how much more or less we should
3143 * try to allocate from this device during
3144 * this iteration around the rotor.
3145 * For example, if a device is 80% full
3146 * and the pool is 20% full then we should
3147 * reduce allocations by 60% on this device.
3149 * mg_bias = (20 - 80) * 512K / 100 = -307K
3151 * This reduces allocations by 307K for this
3154 mg
->mg_bias
= ((cu
- vu
) *
3155 (int64_t)mg
->mg_aliquot
) / 100;
3156 } else if (!metaslab_bias_enabled
) {
3160 if (atomic_add_64_nv(&mc
->mc_aliquot
, asize
) >=
3161 mg
->mg_aliquot
+ mg
->mg_bias
) {
3162 mc
->mc_rotor
= mg
->mg_next
;
3166 DVA_SET_VDEV(&dva
[d
], vd
->vdev_id
);
3167 DVA_SET_OFFSET(&dva
[d
], offset
);
3168 DVA_SET_GANG(&dva
[d
], !!(flags
& METASLAB_GANG_HEADER
));
3169 DVA_SET_ASIZE(&dva
[d
], asize
);
3174 mc
->mc_rotor
= mg
->mg_next
;
3176 } while ((mg
= mg
->mg_next
) != rotor
);
3179 * If we haven't tried hard, do so now.
3186 bzero(&dva
[d
], sizeof (dva_t
));
3188 metaslab_trace_add(zal
, rotor
, NULL
, psize
, d
, TRACE_ENOSPC
);
3189 return (SET_ERROR(ENOSPC
));
3193 metaslab_free_concrete(vdev_t
*vd
, uint64_t offset
, uint64_t asize
,
3197 spa_t
*spa
= vd
->vdev_spa
;
3199 ASSERT3U(txg
, ==, spa
->spa_syncing_txg
);
3200 ASSERT(vdev_is_concrete(vd
));
3201 ASSERT3U(spa_config_held(spa
, SCL_ALL
, RW_READER
), !=, 0);
3202 ASSERT3U(offset
>> vd
->vdev_ms_shift
, <, vd
->vdev_ms_count
);
3204 msp
= vd
->vdev_ms
[offset
>> vd
->vdev_ms_shift
];
3206 VERIFY(!msp
->ms_condensing
);
3207 VERIFY3U(offset
, >=, msp
->ms_start
);
3208 VERIFY3U(offset
+ asize
, <=, msp
->ms_start
+ msp
->ms_size
);
3209 VERIFY0(P2PHASE(offset
, 1ULL << vd
->vdev_ashift
));
3210 VERIFY0(P2PHASE(asize
, 1ULL << vd
->vdev_ashift
));
3212 metaslab_check_free_impl(vd
, offset
, asize
);
3213 mutex_enter(&msp
->ms_lock
);
3214 if (range_tree_space(msp
->ms_freeingtree
) == 0) {
3215 vdev_dirty(vd
, VDD_METASLAB
, msp
, txg
);
3217 range_tree_add(msp
->ms_freeingtree
, offset
, asize
);
3218 mutex_exit(&msp
->ms_lock
);
3223 metaslab_free_impl_cb(uint64_t inner_offset
, vdev_t
*vd
, uint64_t offset
,
3224 uint64_t size
, void *arg
)
3226 uint64_t *txgp
= arg
;
3228 if (vd
->vdev_ops
->vdev_op_remap
!= NULL
)
3229 vdev_indirect_mark_obsolete(vd
, offset
, size
, *txgp
);
3231 metaslab_free_impl(vd
, offset
, size
, *txgp
);
3235 metaslab_free_impl(vdev_t
*vd
, uint64_t offset
, uint64_t size
,
3238 spa_t
*spa
= vd
->vdev_spa
;
3240 ASSERT3U(spa_config_held(spa
, SCL_ALL
, RW_READER
), !=, 0);
3242 if (txg
> spa_freeze_txg(spa
))
3245 if (spa
->spa_vdev_removal
!= NULL
&&
3246 spa
->spa_vdev_removal
->svr_vdev
== vd
&&
3247 vdev_is_concrete(vd
)) {
3249 * Note: we check if the vdev is concrete because when
3250 * we complete the removal, we first change the vdev to be
3251 * an indirect vdev (in open context), and then (in syncing
3252 * context) clear spa_vdev_removal.
3254 free_from_removing_vdev(vd
, offset
, size
, txg
);
3255 } else if (vd
->vdev_ops
->vdev_op_remap
!= NULL
) {
3256 vdev_indirect_mark_obsolete(vd
, offset
, size
, txg
);
3257 vd
->vdev_ops
->vdev_op_remap(vd
, offset
, size
,
3258 metaslab_free_impl_cb
, &txg
);
3260 metaslab_free_concrete(vd
, offset
, size
, txg
);
3264 typedef struct remap_blkptr_cb_arg
{
3266 spa_remap_cb_t rbca_cb
;
3267 vdev_t
*rbca_remap_vd
;
3268 uint64_t rbca_remap_offset
;
3270 } remap_blkptr_cb_arg_t
;
3273 remap_blkptr_cb(uint64_t inner_offset
, vdev_t
*vd
, uint64_t offset
,
3274 uint64_t size
, void *arg
)
3276 remap_blkptr_cb_arg_t
*rbca
= arg
;
3277 blkptr_t
*bp
= rbca
->rbca_bp
;
3279 /* We can not remap split blocks. */
3280 if (size
!= DVA_GET_ASIZE(&bp
->blk_dva
[0]))
3282 ASSERT0(inner_offset
);
3284 if (rbca
->rbca_cb
!= NULL
) {
3286 * At this point we know that we are not handling split
3287 * blocks and we invoke the callback on the previous
3288 * vdev which must be indirect.
3290 ASSERT3P(rbca
->rbca_remap_vd
->vdev_ops
, ==, &vdev_indirect_ops
);
3292 rbca
->rbca_cb(rbca
->rbca_remap_vd
->vdev_id
,
3293 rbca
->rbca_remap_offset
, size
, rbca
->rbca_cb_arg
);
3295 /* set up remap_blkptr_cb_arg for the next call */
3296 rbca
->rbca_remap_vd
= vd
;
3297 rbca
->rbca_remap_offset
= offset
;
3301 * The phys birth time is that of dva[0]. This ensures that we know
3302 * when each dva was written, so that resilver can determine which
3303 * blocks need to be scrubbed (i.e. those written during the time
3304 * the vdev was offline). It also ensures that the key used in
3305 * the ARC hash table is unique (i.e. dva[0] + phys_birth). If
3306 * we didn't change the phys_birth, a lookup in the ARC for a
3307 * remapped BP could find the data that was previously stored at
3308 * this vdev + offset.
3310 vdev_t
*oldvd
= vdev_lookup_top(vd
->vdev_spa
,
3311 DVA_GET_VDEV(&bp
->blk_dva
[0]));
3312 vdev_indirect_births_t
*vib
= oldvd
->vdev_indirect_births
;
3313 bp
->blk_phys_birth
= vdev_indirect_births_physbirth(vib
,
3314 DVA_GET_OFFSET(&bp
->blk_dva
[0]), DVA_GET_ASIZE(&bp
->blk_dva
[0]));
3316 DVA_SET_VDEV(&bp
->blk_dva
[0], vd
->vdev_id
);
3317 DVA_SET_OFFSET(&bp
->blk_dva
[0], offset
);
3321 * If the block pointer contains any indirect DVAs, modify them to refer to
3322 * concrete DVAs. Note that this will sometimes not be possible, leaving
3323 * the indirect DVA in place. This happens if the indirect DVA spans multiple
3324 * segments in the mapping (i.e. it is a "split block").
3326 * If the BP was remapped, calls the callback on the original dva (note the
3327 * callback can be called multiple times if the original indirect DVA refers
3328 * to another indirect DVA, etc).
3330 * Returns TRUE if the BP was remapped.
3333 spa_remap_blkptr(spa_t
*spa
, blkptr_t
*bp
, spa_remap_cb_t callback
, void *arg
)
3335 remap_blkptr_cb_arg_t rbca
;
3337 if (!zfs_remap_blkptr_enable
)
3340 if (!spa_feature_is_enabled(spa
, SPA_FEATURE_OBSOLETE_COUNTS
))
3344 * Dedup BP's can not be remapped, because ddt_phys_select() depends
3345 * on DVA[0] being the same in the BP as in the DDT (dedup table).
3347 if (BP_GET_DEDUP(bp
))
3351 * Gang blocks can not be remapped, because
3352 * zio_checksum_gang_verifier() depends on the DVA[0] that's in
3353 * the BP used to read the gang block header (GBH) being the same
3354 * as the DVA[0] that we allocated for the GBH.
3360 * Embedded BP's have no DVA to remap.
3362 if (BP_GET_NDVAS(bp
) < 1)
3366 * Note: we only remap dva[0]. If we remapped other dvas, we
3367 * would no longer know what their phys birth txg is.
3369 dva_t
*dva
= &bp
->blk_dva
[0];
3371 uint64_t offset
= DVA_GET_OFFSET(dva
);
3372 uint64_t size
= DVA_GET_ASIZE(dva
);
3373 vdev_t
*vd
= vdev_lookup_top(spa
, DVA_GET_VDEV(dva
));
3375 if (vd
->vdev_ops
->vdev_op_remap
== NULL
)
3379 rbca
.rbca_cb
= callback
;
3380 rbca
.rbca_remap_vd
= vd
;
3381 rbca
.rbca_remap_offset
= offset
;
3382 rbca
.rbca_cb_arg
= arg
;
3385 * remap_blkptr_cb() will be called in order for each level of
3386 * indirection, until a concrete vdev is reached or a split block is
3387 * encountered. old_vd and old_offset are updated within the callback
3388 * as we go from the one indirect vdev to the next one (either concrete
3389 * or indirect again) in that order.
3391 vd
->vdev_ops
->vdev_op_remap(vd
, offset
, size
, remap_blkptr_cb
, &rbca
);
3393 /* Check if the DVA wasn't remapped because it is a split block */
3394 if (DVA_GET_VDEV(&rbca
.rbca_bp
->blk_dva
[0]) == vd
->vdev_id
)
3401 * Undo the allocation of a DVA which happened in the given transaction group.
3404 metaslab_unalloc_dva(spa_t
*spa
, const dva_t
*dva
, uint64_t txg
)
3408 uint64_t vdev
= DVA_GET_VDEV(dva
);
3409 uint64_t offset
= DVA_GET_OFFSET(dva
);
3410 uint64_t size
= DVA_GET_ASIZE(dva
);
3412 ASSERT(DVA_IS_VALID(dva
));
3413 ASSERT3U(spa_config_held(spa
, SCL_ALL
, RW_READER
), !=, 0);
3415 if (txg
> spa_freeze_txg(spa
))
3418 if ((vd
= vdev_lookup_top(spa
, vdev
)) == NULL
||
3419 (offset
>> vd
->vdev_ms_shift
) >= vd
->vdev_ms_count
) {
3420 cmn_err(CE_WARN
, "metaslab_free_dva(): bad DVA %llu:%llu",
3421 (u_longlong_t
)vdev
, (u_longlong_t
)offset
);
3426 ASSERT(!vd
->vdev_removing
);
3427 ASSERT(vdev_is_concrete(vd
));
3428 ASSERT0(vd
->vdev_indirect_config
.vic_mapping_object
);
3429 ASSERT3P(vd
->vdev_indirect_mapping
, ==, NULL
);
3431 if (DVA_GET_GANG(dva
))
3432 size
= vdev_psize_to_asize(vd
, SPA_GANGBLOCKSIZE
);
3434 msp
= vd
->vdev_ms
[offset
>> vd
->vdev_ms_shift
];
3436 mutex_enter(&msp
->ms_lock
);
3437 range_tree_remove(msp
->ms_alloctree
[txg
& TXG_MASK
],
3440 VERIFY(!msp
->ms_condensing
);
3441 VERIFY3U(offset
, >=, msp
->ms_start
);
3442 VERIFY3U(offset
+ size
, <=, msp
->ms_start
+ msp
->ms_size
);
3443 VERIFY3U(range_tree_space(msp
->ms_tree
) + size
, <=,
3445 VERIFY0(P2PHASE(offset
, 1ULL << vd
->vdev_ashift
));
3446 VERIFY0(P2PHASE(size
, 1ULL << vd
->vdev_ashift
));
3447 range_tree_add(msp
->ms_tree
, offset
, size
);
3448 mutex_exit(&msp
->ms_lock
);
3452 * Free the block represented by DVA in the context of the specified
3453 * transaction group.
3456 metaslab_free_dva(spa_t
*spa
, const dva_t
*dva
, uint64_t txg
)
3458 uint64_t vdev
= DVA_GET_VDEV(dva
);
3459 uint64_t offset
= DVA_GET_OFFSET(dva
);
3460 uint64_t size
= DVA_GET_ASIZE(dva
);
3461 vdev_t
*vd
= vdev_lookup_top(spa
, vdev
);
3463 ASSERT(DVA_IS_VALID(dva
));
3464 ASSERT3U(spa_config_held(spa
, SCL_ALL
, RW_READER
), !=, 0);
3466 if (DVA_GET_GANG(dva
)) {
3467 size
= vdev_psize_to_asize(vd
, SPA_GANGBLOCKSIZE
);
3470 metaslab_free_impl(vd
, offset
, size
, txg
);
3474 * Reserve some allocation slots. The reservation system must be called
3475 * before we call into the allocator. If there aren't any available slots
3476 * then the I/O will be throttled until an I/O completes and its slots are
3477 * freed up. The function returns true if it was successful in placing
3481 metaslab_class_throttle_reserve(metaslab_class_t
*mc
, int slots
, zio_t
*zio
,
3484 uint64_t available_slots
= 0;
3485 boolean_t slot_reserved
= B_FALSE
;
3487 ASSERT(mc
->mc_alloc_throttle_enabled
);
3488 mutex_enter(&mc
->mc_lock
);
3490 uint64_t reserved_slots
= refcount_count(&mc
->mc_alloc_slots
);
3491 if (reserved_slots
< mc
->mc_alloc_max_slots
)
3492 available_slots
= mc
->mc_alloc_max_slots
- reserved_slots
;
3494 if (slots
<= available_slots
|| GANG_ALLOCATION(flags
)) {
3496 * We reserve the slots individually so that we can unreserve
3497 * them individually when an I/O completes.
3499 for (int d
= 0; d
< slots
; d
++) {
3500 reserved_slots
= refcount_add(&mc
->mc_alloc_slots
, zio
);
3502 zio
->io_flags
|= ZIO_FLAG_IO_ALLOCATING
;
3503 slot_reserved
= B_TRUE
;
3506 mutex_exit(&mc
->mc_lock
);
3507 return (slot_reserved
);
3511 metaslab_class_throttle_unreserve(metaslab_class_t
*mc
, int slots
, zio_t
*zio
)
3513 ASSERT(mc
->mc_alloc_throttle_enabled
);
3514 mutex_enter(&mc
->mc_lock
);
3515 for (int d
= 0; d
< slots
; d
++) {
3516 (void) refcount_remove(&mc
->mc_alloc_slots
, zio
);
3518 mutex_exit(&mc
->mc_lock
);
3522 metaslab_claim_concrete(vdev_t
*vd
, uint64_t offset
, uint64_t size
,
3526 spa_t
*spa
= vd
->vdev_spa
;
3529 if (offset
>> vd
->vdev_ms_shift
>= vd
->vdev_ms_count
)
3532 ASSERT3P(vd
->vdev_ms
, !=, NULL
);
3533 msp
= vd
->vdev_ms
[offset
>> vd
->vdev_ms_shift
];
3535 mutex_enter(&msp
->ms_lock
);
3537 if ((txg
!= 0 && spa_writeable(spa
)) || !msp
->ms_loaded
)
3538 error
= metaslab_activate(msp
, METASLAB_WEIGHT_SECONDARY
);
3540 if (error
== 0 && !range_tree_contains(msp
->ms_tree
, offset
, size
))
3541 error
= SET_ERROR(ENOENT
);
3543 if (error
|| txg
== 0) { /* txg == 0 indicates dry run */
3544 mutex_exit(&msp
->ms_lock
);
3548 VERIFY(!msp
->ms_condensing
);
3549 VERIFY0(P2PHASE(offset
, 1ULL << vd
->vdev_ashift
));
3550 VERIFY0(P2PHASE(size
, 1ULL << vd
->vdev_ashift
));
3551 VERIFY3U(range_tree_space(msp
->ms_tree
) - size
, <=, msp
->ms_size
);
3552 range_tree_remove(msp
->ms_tree
, offset
, size
);
3554 if (spa_writeable(spa
)) { /* don't dirty if we're zdb(1M) */
3555 if (range_tree_space(msp
->ms_alloctree
[txg
& TXG_MASK
]) == 0)
3556 vdev_dirty(vd
, VDD_METASLAB
, msp
, txg
);
3557 range_tree_add(msp
->ms_alloctree
[txg
& TXG_MASK
], offset
, size
);
3560 mutex_exit(&msp
->ms_lock
);
3565 typedef struct metaslab_claim_cb_arg_t
{
3568 } metaslab_claim_cb_arg_t
;
3572 metaslab_claim_impl_cb(uint64_t inner_offset
, vdev_t
*vd
, uint64_t offset
,
3573 uint64_t size
, void *arg
)
3575 metaslab_claim_cb_arg_t
*mcca_arg
= arg
;
3577 if (mcca_arg
->mcca_error
== 0) {
3578 mcca_arg
->mcca_error
= metaslab_claim_concrete(vd
, offset
,
3579 size
, mcca_arg
->mcca_txg
);
3584 metaslab_claim_impl(vdev_t
*vd
, uint64_t offset
, uint64_t size
, uint64_t txg
)
3586 if (vd
->vdev_ops
->vdev_op_remap
!= NULL
) {
3587 metaslab_claim_cb_arg_t arg
;
3590 * Only zdb(1M) can claim on indirect vdevs. This is used
3591 * to detect leaks of mapped space (that are not accounted
3592 * for in the obsolete counts, spacemap, or bpobj).
3594 ASSERT(!spa_writeable(vd
->vdev_spa
));
3598 vd
->vdev_ops
->vdev_op_remap(vd
, offset
, size
,
3599 metaslab_claim_impl_cb
, &arg
);
3601 if (arg
.mcca_error
== 0) {
3602 arg
.mcca_error
= metaslab_claim_concrete(vd
,
3605 return (arg
.mcca_error
);
3607 return (metaslab_claim_concrete(vd
, offset
, size
, txg
));
3612 * Intent log support: upon opening the pool after a crash, notify the SPA
3613 * of blocks that the intent log has allocated for immediate write, but
3614 * which are still considered free by the SPA because the last transaction
3615 * group didn't commit yet.
3618 metaslab_claim_dva(spa_t
*spa
, const dva_t
*dva
, uint64_t txg
)
3620 uint64_t vdev
= DVA_GET_VDEV(dva
);
3621 uint64_t offset
= DVA_GET_OFFSET(dva
);
3622 uint64_t size
= DVA_GET_ASIZE(dva
);
3625 if ((vd
= vdev_lookup_top(spa
, vdev
)) == NULL
) {
3626 return (SET_ERROR(ENXIO
));
3629 ASSERT(DVA_IS_VALID(dva
));
3631 if (DVA_GET_GANG(dva
))
3632 size
= vdev_psize_to_asize(vd
, SPA_GANGBLOCKSIZE
);
3634 return (metaslab_claim_impl(vd
, offset
, size
, txg
));
3638 metaslab_alloc(spa_t
*spa
, metaslab_class_t
*mc
, uint64_t psize
, blkptr_t
*bp
,
3639 int ndvas
, uint64_t txg
, blkptr_t
*hintbp
, int flags
,
3640 zio_alloc_list_t
*zal
, zio_t
*zio
)
3642 dva_t
*dva
= bp
->blk_dva
;
3643 dva_t
*hintdva
= hintbp
->blk_dva
;
3646 ASSERT(bp
->blk_birth
== 0);
3647 ASSERT(BP_PHYSICAL_BIRTH(bp
) == 0);
3649 spa_config_enter(spa
, SCL_ALLOC
, FTAG
, RW_READER
);
3651 if (mc
->mc_rotor
== NULL
) { /* no vdevs in this class */
3652 spa_config_exit(spa
, SCL_ALLOC
, FTAG
);
3653 return (SET_ERROR(ENOSPC
));
3656 ASSERT(ndvas
> 0 && ndvas
<= spa_max_replication(spa
));
3657 ASSERT(BP_GET_NDVAS(bp
) == 0);
3658 ASSERT(hintbp
== NULL
|| ndvas
<= BP_GET_NDVAS(hintbp
));
3659 ASSERT3P(zal
, !=, NULL
);
3661 for (int d
= 0; d
< ndvas
; d
++) {
3662 error
= metaslab_alloc_dva(spa
, mc
, psize
, dva
, d
, hintdva
,
3665 for (d
--; d
>= 0; d
--) {
3666 metaslab_unalloc_dva(spa
, &dva
[d
], txg
);
3667 metaslab_group_alloc_decrement(spa
,
3668 DVA_GET_VDEV(&dva
[d
]), zio
, flags
);
3669 bzero(&dva
[d
], sizeof (dva_t
));
3671 spa_config_exit(spa
, SCL_ALLOC
, FTAG
);
3675 * Update the metaslab group's queue depth
3676 * based on the newly allocated dva.
3678 metaslab_group_alloc_increment(spa
,
3679 DVA_GET_VDEV(&dva
[d
]), zio
, flags
);
3684 ASSERT(BP_GET_NDVAS(bp
) == ndvas
);
3686 spa_config_exit(spa
, SCL_ALLOC
, FTAG
);
3688 BP_SET_BIRTH(bp
, txg
, txg
);
3694 metaslab_free(spa_t
*spa
, const blkptr_t
*bp
, uint64_t txg
, boolean_t now
)
3696 const dva_t
*dva
= bp
->blk_dva
;
3697 int ndvas
= BP_GET_NDVAS(bp
);
3699 ASSERT(!BP_IS_HOLE(bp
));
3700 ASSERT(!now
|| bp
->blk_birth
>= spa_syncing_txg(spa
));
3702 spa_config_enter(spa
, SCL_FREE
, FTAG
, RW_READER
);
3704 for (int d
= 0; d
< ndvas
; d
++) {
3706 metaslab_unalloc_dva(spa
, &dva
[d
], txg
);
3708 metaslab_free_dva(spa
, &dva
[d
], txg
);
3712 spa_config_exit(spa
, SCL_FREE
, FTAG
);
3716 metaslab_claim(spa_t
*spa
, const blkptr_t
*bp
, uint64_t txg
)
3718 const dva_t
*dva
= bp
->blk_dva
;
3719 int ndvas
= BP_GET_NDVAS(bp
);
3722 ASSERT(!BP_IS_HOLE(bp
));
3726 * First do a dry run to make sure all DVAs are claimable,
3727 * so we don't have to unwind from partial failures below.
3729 if ((error
= metaslab_claim(spa
, bp
, 0)) != 0)
3733 spa_config_enter(spa
, SCL_ALLOC
, FTAG
, RW_READER
);
3735 for (int d
= 0; d
< ndvas
; d
++)
3736 if ((error
= metaslab_claim_dva(spa
, &dva
[d
], txg
)) != 0)
3739 spa_config_exit(spa
, SCL_ALLOC
, FTAG
);
3741 ASSERT(error
== 0 || txg
== 0);
3748 metaslab_check_free_impl_cb(uint64_t inner
, vdev_t
*vd
, uint64_t offset
,
3749 uint64_t size
, void *arg
)
3751 if (vd
->vdev_ops
== &vdev_indirect_ops
)
3754 metaslab_check_free_impl(vd
, offset
, size
);
3758 metaslab_check_free_impl(vdev_t
*vd
, uint64_t offset
, uint64_t size
)
3761 spa_t
*spa
= vd
->vdev_spa
;
3763 if ((zfs_flags
& ZFS_DEBUG_ZIO_FREE
) == 0)
3766 if (vd
->vdev_ops
->vdev_op_remap
!= NULL
) {
3767 vd
->vdev_ops
->vdev_op_remap(vd
, offset
, size
,
3768 metaslab_check_free_impl_cb
, NULL
);
3772 ASSERT(vdev_is_concrete(vd
));
3773 ASSERT3U(offset
>> vd
->vdev_ms_shift
, <, vd
->vdev_ms_count
);
3774 ASSERT3U(spa_config_held(spa
, SCL_ALL
, RW_READER
), !=, 0);
3776 msp
= vd
->vdev_ms
[offset
>> vd
->vdev_ms_shift
];
3778 mutex_enter(&msp
->ms_lock
);
3780 range_tree_verify(msp
->ms_tree
, offset
, size
);
3782 range_tree_verify(msp
->ms_freeingtree
, offset
, size
);
3783 range_tree_verify(msp
->ms_freedtree
, offset
, size
);
3784 for (int j
= 0; j
< TXG_DEFER_SIZE
; j
++)
3785 range_tree_verify(msp
->ms_defertree
[j
], offset
, size
);
3786 mutex_exit(&msp
->ms_lock
);
3790 metaslab_check_free(spa_t
*spa
, const blkptr_t
*bp
)
3792 if ((zfs_flags
& ZFS_DEBUG_ZIO_FREE
) == 0)
3795 spa_config_enter(spa
, SCL_VDEV
, FTAG
, RW_READER
);
3796 for (int i
= 0; i
< BP_GET_NDVAS(bp
); i
++) {
3797 uint64_t vdev
= DVA_GET_VDEV(&bp
->blk_dva
[i
]);
3798 vdev_t
*vd
= vdev_lookup_top(spa
, vdev
);
3799 uint64_t offset
= DVA_GET_OFFSET(&bp
->blk_dva
[i
]);
3800 uint64_t size
= DVA_GET_ASIZE(&bp
->blk_dva
[i
]);
3802 if (DVA_GET_GANG(&bp
->blk_dva
[i
]))
3803 size
= vdev_psize_to_asize(vd
, SPA_GANGBLOCKSIZE
);
3805 ASSERT3P(vd
, !=, NULL
);
3807 metaslab_check_free_impl(vd
, offset
, size
);
3809 spa_config_exit(spa
, SCL_VDEV
, FTAG
);