1 /*
2 * CDDL HEADER START
3 *
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.
7 *
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.
12 *
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]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2011, 2018 by Delphix. All rights reserved.
24 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
25 * Copyright (c) 2014 Integros [integros.com]
26 * Copyright (c) 2017, Intel Corporation.
27 */
28
29 #include <sys/zfs_context.h>
30 #include <sys/dmu.h>
31 #include <sys/dmu_tx.h>
32 #include <sys/space_map.h>
33 #include <sys/metaslab_impl.h>
34 #include <sys/vdev_impl.h>
35 #include <sys/zio.h>
36 #include <sys/spa_impl.h>
37 #include <sys/zfeature.h>
38 #include <sys/vdev_indirect_mapping.h>
39 #include <sys/zap.h>
40
41 #define GANG_ALLOCATION(flags) \
42 ((flags) & (METASLAB_GANG_CHILD | METASLAB_GANG_HEADER))
43
44 uint64_t metaslab_aliquot = 512ULL << 10;
45 uint64_t metaslab_force_ganging = SPA_MAXBLOCKSIZE + 1; /* force gang blocks */
46
47 /*
48 * Since we can touch multiple metaslabs (and their respective space maps)
49 * with each transaction group, we benefit from having a smaller space map
50 * block size since it allows us to issue more I/O operations scattered
51 * around the disk.
52 */
53 int zfs_metaslab_sm_blksz = (1 << 12);
54
55 /*
56 * The in-core space map representation is more compact than its on-disk form.
57 * The zfs_condense_pct determines how much more compact the in-core
58 * space map representation must be before we compact it on-disk.
59 * Values should be greater than or equal to 100.
60 */
61 int zfs_condense_pct = 200;
62
63 /*
64 * Condensing a metaslab is not guaranteed to actually reduce the amount of
65 * space used on disk. In particular, a space map uses data in increments of
66 * MAX(1 << ashift, space_map_blksize), so a metaslab might use the
67 * same number of blocks after condensing. Since the goal of condensing is to
68 * reduce the number of IOPs required to read the space map, we only want to
69 * condense when we can be sure we will reduce the number of blocks used by the
70 * space map. Unfortunately, we cannot precisely compute whether or not this is
71 * the case in metaslab_should_condense since we are holding ms_lock. Instead,
72 * we apply the following heuristic: do not condense a spacemap unless the
73 * uncondensed size consumes greater than zfs_metaslab_condense_block_threshold
74 * blocks.
75 */
76 int zfs_metaslab_condense_block_threshold = 4;
77
78 /*
79 * The zfs_mg_noalloc_threshold defines which metaslab groups should
80 * be eligible for allocation. The value is defined as a percentage of
81 * free space. Metaslab groups that have more free space than
82 * zfs_mg_noalloc_threshold are always eligible for allocations. Once
83 * a metaslab group's free space is less than or equal to the
84 * zfs_mg_noalloc_threshold the allocator will avoid allocating to that
85 * group unless all groups in the pool have reached zfs_mg_noalloc_threshold.
86 * Once all groups in the pool reach zfs_mg_noalloc_threshold then all
87 * groups are allowed to accept allocations. Gang blocks are always
88 * eligible to allocate on any metaslab group. The default value of 0 means
89 * no metaslab group will be excluded based on this criterion.
90 */
91 int zfs_mg_noalloc_threshold = 0;
92
93 /*
94 * Metaslab groups are considered eligible for allocations if their
95 * fragmenation metric (measured as a percentage) is less than or equal to
96 * zfs_mg_fragmentation_threshold. If a metaslab group exceeds this threshold
97 * then it will be skipped unless all metaslab groups within the metaslab
98 * class have also crossed this threshold.
99 */
100 int zfs_mg_fragmentation_threshold = 85;
101
102 /*
103 * Allow metaslabs to keep their active state as long as their fragmentation
104 * percentage is less than or equal to zfs_metaslab_fragmentation_threshold. An
105 * active metaslab that exceeds this threshold will no longer keep its active
106 * status allowing better metaslabs to be selected.
107 */
108 int zfs_metaslab_fragmentation_threshold = 70;
109
110 /*
111 * When set will load all metaslabs when pool is first opened.
112 */
113 int metaslab_debug_load = 0;
114
115 /*
116 * When set will prevent metaslabs from being unloaded.
117 */
118 int metaslab_debug_unload = 0;
119
120 /*
121 * Minimum size which forces the dynamic allocator to change
122 * it's allocation strategy. Once the space map cannot satisfy
123 * an allocation of this size then it switches to using more
124 * aggressive strategy (i.e search by size rather than offset).
125 */
126 uint64_t metaslab_df_alloc_threshold = SPA_OLD_MAXBLOCKSIZE;
127
128 /*
129 * The minimum free space, in percent, which must be available
130 * in a space map to continue allocations in a first-fit fashion.
131 * Once the space map's free space drops below this level we dynamically
132 * switch to using best-fit allocations.
133 */
134 int metaslab_df_free_pct = 4;
135
136 /*
137 * A metaslab is considered "free" if it contains a contiguous
138 * segment which is greater than metaslab_min_alloc_size.
139 */
140 uint64_t metaslab_min_alloc_size = DMU_MAX_ACCESS;
141
142 /*
143 * Percentage of all cpus that can be used by the metaslab taskq.
144 */
145 int metaslab_load_pct = 50;
146
147 /*
148 * Determines how many txgs a metaslab may remain loaded without having any
149 * allocations from it. As long as a metaslab continues to be used we will
150 * keep it loaded.
151 */
152 int metaslab_unload_delay = TXG_SIZE * 2;
153
154 /*
155 * Max number of metaslabs per group to preload.
156 */
157 int metaslab_preload_limit = SPA_DVAS_PER_BP;
158
159 /*
160 * Enable/disable preloading of metaslab.
161 */
162 boolean_t metaslab_preload_enabled = B_TRUE;
163
164 /*
165 * Enable/disable fragmentation weighting on metaslabs.
166 */
167 boolean_t metaslab_fragmentation_factor_enabled = B_TRUE;
168
169 /*
170 * Enable/disable lba weighting (i.e. outer tracks are given preference).
171 */
172 boolean_t metaslab_lba_weighting_enabled = B_TRUE;
173
174 /*
175 * Enable/disable metaslab group biasing.
176 */
177 boolean_t metaslab_bias_enabled = B_TRUE;
178
179 /*
180 * Enable/disable remapping of indirect DVAs to their concrete vdevs.
181 */
182 boolean_t zfs_remap_blkptr_enable = B_TRUE;
183
184 /*
185 * Enable/disable segment-based metaslab selection.
186 */
187 boolean_t zfs_metaslab_segment_weight_enabled = B_TRUE;
188
189 /*
190 * When using segment-based metaslab selection, we will continue
191 * allocating from the active metaslab until we have exhausted
192 * zfs_metaslab_switch_threshold of its buckets.
193 */
194 int zfs_metaslab_switch_threshold = 2;
195
196 /*
197 * Internal switch to enable/disable the metaslab allocation tracing
198 * facility.
199 */
200 boolean_t metaslab_trace_enabled = B_TRUE;
201
202 /*
203 * Maximum entries that the metaslab allocation tracing facility will keep
204 * in a given list when running in non-debug mode. We limit the number
205 * of entries in non-debug mode to prevent us from using up too much memory.
206 * The limit should be sufficiently large that we don't expect any allocation
207 * to every exceed this value. In debug mode, the system will panic if this
208 * limit is ever reached allowing for further investigation.
209 */
210 uint64_t metaslab_trace_max_entries = 5000;
211
212 static uint64_t metaslab_weight(metaslab_t *);
213 static void metaslab_set_fragmentation(metaslab_t *);
214 static void metaslab_free_impl(vdev_t *, uint64_t, uint64_t, boolean_t);
215 static void metaslab_check_free_impl(vdev_t *, uint64_t, uint64_t);
216 static void metaslab_passivate(metaslab_t *msp, uint64_t weight);
217 static uint64_t metaslab_weight_from_range_tree(metaslab_t *msp);
218
219 kmem_cache_t *metaslab_alloc_trace_cache;
220
221 /*
222 * ==========================================================================
223 * Metaslab classes
224 * ==========================================================================
225 */
226 metaslab_class_t *
227 metaslab_class_create(spa_t *spa, metaslab_ops_t *ops)
228 {
229 metaslab_class_t *mc;
230
231 mc = kmem_zalloc(sizeof (metaslab_class_t), KM_SLEEP);
232
233 mc->mc_spa = spa;
234 mc->mc_rotor = NULL;
235 mc->mc_ops = ops;
236 mutex_init(&mc->mc_lock, NULL, MUTEX_DEFAULT, NULL);
237 mc->mc_alloc_slots = kmem_zalloc(spa->spa_alloc_count *
238 sizeof (zfs_refcount_t), KM_SLEEP);
239 mc->mc_alloc_max_slots = kmem_zalloc(spa->spa_alloc_count *
240 sizeof (uint64_t), KM_SLEEP);
241 for (int i = 0; i < spa->spa_alloc_count; i++)
242 zfs_refcount_create_tracked(&mc->mc_alloc_slots[i]);
243
244 return (mc);
245 }
246
247 void
248 metaslab_class_destroy(metaslab_class_t *mc)
249 {
250 ASSERT(mc->mc_rotor == NULL);
251 ASSERT(mc->mc_alloc == 0);
252 ASSERT(mc->mc_deferred == 0);
253 ASSERT(mc->mc_space == 0);
254 ASSERT(mc->mc_dspace == 0);
255
256 for (int i = 0; i < mc->mc_spa->spa_alloc_count; i++)
257 zfs_refcount_destroy(&mc->mc_alloc_slots[i]);
258 kmem_free(mc->mc_alloc_slots, mc->mc_spa->spa_alloc_count *
259 sizeof (zfs_refcount_t));
260 kmem_free(mc->mc_alloc_max_slots, mc->mc_spa->spa_alloc_count *
261 sizeof (uint64_t));
262 mutex_destroy(&mc->mc_lock);
263 kmem_free(mc, sizeof (metaslab_class_t));
264 }
265
266 int
267 metaslab_class_validate(metaslab_class_t *mc)
268 {
269 metaslab_group_t *mg;
270 vdev_t *vd;
271
272 /*
273 * Must hold one of the spa_config locks.
274 */
275 ASSERT(spa_config_held(mc->mc_spa, SCL_ALL, RW_READER) ||
276 spa_config_held(mc->mc_spa, SCL_ALL, RW_WRITER));
277
278 if ((mg = mc->mc_rotor) == NULL)
279 return (0);
280
281 do {
282 vd = mg->mg_vd;
283 ASSERT(vd->vdev_mg != NULL);
284 ASSERT3P(vd->vdev_top, ==, vd);
285 ASSERT3P(mg->mg_class, ==, mc);
286 ASSERT3P(vd->vdev_ops, !=, &vdev_hole_ops);
287 } while ((mg = mg->mg_next) != mc->mc_rotor);
288
289 return (0);
290 }
291
292 static void
293 metaslab_class_space_update(metaslab_class_t *mc, int64_t alloc_delta,
294 int64_t defer_delta, int64_t space_delta, int64_t dspace_delta)
295 {
296 atomic_add_64(&mc->mc_alloc, alloc_delta);
297 atomic_add_64(&mc->mc_deferred, defer_delta);
298 atomic_add_64(&mc->mc_space, space_delta);
299 atomic_add_64(&mc->mc_dspace, dspace_delta);
300 }
301
302 uint64_t
303 metaslab_class_get_alloc(metaslab_class_t *mc)
304 {
305 return (mc->mc_alloc);
306 }
307
308 uint64_t
309 metaslab_class_get_deferred(metaslab_class_t *mc)
310 {
311 return (mc->mc_deferred);
312 }
313
314 uint64_t
315 metaslab_class_get_space(metaslab_class_t *mc)
316 {
317 return (mc->mc_space);
318 }
319
320 uint64_t
321 metaslab_class_get_dspace(metaslab_class_t *mc)
322 {
323 return (spa_deflate(mc->mc_spa) ? mc->mc_dspace : mc->mc_space);
324 }
325
326 void
327 metaslab_class_histogram_verify(metaslab_class_t *mc)
328 {
329 spa_t *spa = mc->mc_spa;
330 vdev_t *rvd = spa->spa_root_vdev;
331 uint64_t *mc_hist;
332 int i;
333
334 if ((zfs_flags & ZFS_DEBUG_HISTOGRAM_VERIFY) == 0)
335 return;
336
337 mc_hist = kmem_zalloc(sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE,
338 KM_SLEEP);
339
340 for (int c = 0; c < rvd->vdev_children; c++) {
341 vdev_t *tvd = rvd->vdev_child[c];
342 metaslab_group_t *mg = tvd->vdev_mg;
343
344 /*
345 * Skip any holes, uninitialized top-levels, or
346 * vdevs that are not in this metalab class.
347 */
348 if (!vdev_is_concrete(tvd) || tvd->vdev_ms_shift == 0 ||
349 mg->mg_class != mc) {
350 continue;
351 }
352
353 for (i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i++)
354 mc_hist[i] += mg->mg_histogram[i];
355 }
356
357 for (i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i++)
358 VERIFY3U(mc_hist[i], ==, mc->mc_histogram[i]);
359
360 kmem_free(mc_hist, sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE);
361 }
362
363 /*
364 * Calculate the metaslab class's fragmentation metric. The metric
365 * is weighted based on the space contribution of each metaslab group.
366 * The return value will be a number between 0 and 100 (inclusive), or
367 * ZFS_FRAG_INVALID if the metric has not been set. See comment above the
368 * zfs_frag_table for more information about the metric.
369 */
370 uint64_t
371 metaslab_class_fragmentation(metaslab_class_t *mc)
372 {
373 vdev_t *rvd = mc->mc_spa->spa_root_vdev;
374 uint64_t fragmentation = 0;
375
376 spa_config_enter(mc->mc_spa, SCL_VDEV, FTAG, RW_READER);
377
378 for (int c = 0; c < rvd->vdev_children; c++) {
379 vdev_t *tvd = rvd->vdev_child[c];
380 metaslab_group_t *mg = tvd->vdev_mg;
381
382 /*
383 * Skip any holes, uninitialized top-levels,
384 * or vdevs that are not in this metalab class.
385 */
386 if (!vdev_is_concrete(tvd) || tvd->vdev_ms_shift == 0 ||
387 mg->mg_class != mc) {
388 continue;
389 }
390
391 /*
392 * If a metaslab group does not contain a fragmentation
393 * metric then just bail out.
394 */
395 if (mg->mg_fragmentation == ZFS_FRAG_INVALID) {
396 spa_config_exit(mc->mc_spa, SCL_VDEV, FTAG);
397 return (ZFS_FRAG_INVALID);
398 }
399
400 /*
401 * Determine how much this metaslab_group is contributing
402 * to the overall pool fragmentation metric.
403 */
404 fragmentation += mg->mg_fragmentation *
405 metaslab_group_get_space(mg);
406 }
407 fragmentation /= metaslab_class_get_space(mc);
408
409 ASSERT3U(fragmentation, <=, 100);
410 spa_config_exit(mc->mc_spa, SCL_VDEV, FTAG);
411 return (fragmentation);
412 }
413
414 /*
415 * Calculate the amount of expandable space that is available in
416 * this metaslab class. If a device is expanded then its expandable
417 * space will be the amount of allocatable space that is currently not
418 * part of this metaslab class.
419 */
420 uint64_t
421 metaslab_class_expandable_space(metaslab_class_t *mc)
422 {
423 vdev_t *rvd = mc->mc_spa->spa_root_vdev;
424 uint64_t space = 0;
425
426 spa_config_enter(mc->mc_spa, SCL_VDEV, FTAG, RW_READER);
427 for (int c = 0; c < rvd->vdev_children; c++) {
428 uint64_t tspace;
429 vdev_t *tvd = rvd->vdev_child[c];
430 metaslab_group_t *mg = tvd->vdev_mg;
431
432 if (!vdev_is_concrete(tvd) || tvd->vdev_ms_shift == 0 ||
433 mg->mg_class != mc) {
434 continue;
435 }
436
437 /*
438 * Calculate if we have enough space to add additional
439 * metaslabs. We report the expandable space in terms
440 * of the metaslab size since that's the unit of expansion.
441 * Adjust by efi system partition size.
442 */
443 tspace = tvd->vdev_max_asize - tvd->vdev_asize;
444 if (tspace > mc->mc_spa->spa_bootsize) {
445 tspace -= mc->mc_spa->spa_bootsize;
446 }
447 space += P2ALIGN(tspace, 1ULL << tvd->vdev_ms_shift);
448 }
449 spa_config_exit(mc->mc_spa, SCL_VDEV, FTAG);
450 return (space);
451 }
452
453 static int
454 metaslab_compare(const void *x1, const void *x2)
455 {
456 const metaslab_t *m1 = x1;
457 const metaslab_t *m2 = x2;
458
459 int sort1 = 0;
460 int sort2 = 0;
461 if (m1->ms_allocator != -1 && m1->ms_primary)
462 sort1 = 1;
463 else if (m1->ms_allocator != -1 && !m1->ms_primary)
464 sort1 = 2;
465 if (m2->ms_allocator != -1 && m2->ms_primary)
466 sort2 = 1;
467 else if (m2->ms_allocator != -1 && !m2->ms_primary)
468 sort2 = 2;
469
470 /*
471 * Sort inactive metaslabs first, then primaries, then secondaries. When
472 * selecting a metaslab to allocate from, an allocator first tries its
473 * primary, then secondary active metaslab. If it doesn't have active
474 * metaslabs, or can't allocate from them, it searches for an inactive
475 * metaslab to activate. If it can't find a suitable one, it will steal
476 * a primary or secondary metaslab from another allocator.
477 */
478 if (sort1 < sort2)
479 return (-1);
480 if (sort1 > sort2)
481 return (1);
482
483 if (m1->ms_weight < m2->ms_weight)
484 return (1);
485 if (m1->ms_weight > m2->ms_weight)
486 return (-1);
487
488 /*
489 * If the weights are identical, use the offset to force uniqueness.
490 */
491 if (m1->ms_start < m2->ms_start)
492 return (-1);
493 if (m1->ms_start > m2->ms_start)
494 return (1);
495
496 ASSERT3P(m1, ==, m2);
497
498 return (0);
499 }
500
501 uint64_t
502 metaslab_allocated_space(metaslab_t *msp)
503 {
504 return (msp->ms_allocated_space);
505 }
506
507 /*
508 * Verify that the space accounting on disk matches the in-core range_trees.
509 */
510 static void
511 metaslab_verify_space(metaslab_t *msp, uint64_t txg)
512 {
513 spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
514 uint64_t allocating = 0;
515 uint64_t sm_free_space, msp_free_space;
516
517 ASSERT(MUTEX_HELD(&msp->ms_lock));
518 ASSERT(!msp->ms_condensing);
519
520 if ((zfs_flags & ZFS_DEBUG_METASLAB_VERIFY) == 0)
521 return;
522
523 /*
524 * We can only verify the metaslab space when we're called
525 * from syncing context with a loaded metaslab that has an
526 * allocated space map. Calling this in non-syncing context
527 * does not provide a consistent view of the metaslab since
528 * we're performing allocations in the future.
529 */
530 if (txg != spa_syncing_txg(spa) || msp->ms_sm == NULL ||
531 !msp->ms_loaded)
532 return;
533
534 /*
535 * Even though the smp_alloc field can get negative (e.g.
536 * see vdev_checkpoint_sm), that should never be the case
537 * when it come's to a metaslab's space map.
538 */
539 ASSERT3S(space_map_allocated(msp->ms_sm), >=, 0);
540
541 sm_free_space = msp->ms_size - metaslab_allocated_space(msp);
542
543 /*
544 * Account for future allocations since we would have
545 * already deducted that space from the ms_allocatable.
546 */
547 for (int t = 0; t < TXG_CONCURRENT_STATES; t++) {
548 allocating +=
549 range_tree_space(msp->ms_allocating[(txg + t) & TXG_MASK]);
550 }
551
552 ASSERT3U(msp->ms_deferspace, ==,
553 range_tree_space(msp->ms_defer[0]) +
554 range_tree_space(msp->ms_defer[1]));
555
556 msp_free_space = range_tree_space(msp->ms_allocatable) + allocating +
557 msp->ms_deferspace + range_tree_space(msp->ms_freed);
558
559 VERIFY3U(sm_free_space, ==, msp_free_space);
560 }
561
562 /*
563 * ==========================================================================
564 * Metaslab groups
565 * ==========================================================================
566 */
567 /*
568 * Update the allocatable flag and the metaslab group's capacity.
569 * The allocatable flag is set to true if the capacity is below
570 * the zfs_mg_noalloc_threshold or has a fragmentation value that is
571 * greater than zfs_mg_fragmentation_threshold. If a metaslab group
572 * transitions from allocatable to non-allocatable or vice versa then the
573 * metaslab group's class is updated to reflect the transition.
574 */
575 static void
576 metaslab_group_alloc_update(metaslab_group_t *mg)
577 {
578 vdev_t *vd = mg->mg_vd;
579 metaslab_class_t *mc = mg->mg_class;
580 vdev_stat_t *vs = &vd->vdev_stat;
581 boolean_t was_allocatable;
582 boolean_t was_initialized;
583
584 ASSERT(vd == vd->vdev_top);
585 ASSERT3U(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_READER), ==,
586 SCL_ALLOC);
587
588 mutex_enter(&mg->mg_lock);
589 was_allocatable = mg->mg_allocatable;
590 was_initialized = mg->mg_initialized;
591
592 mg->mg_free_capacity = ((vs->vs_space - vs->vs_alloc) * 100) /
593 (vs->vs_space + 1);
594
595 mutex_enter(&mc->mc_lock);
596
597 /*
598 * If the metaslab group was just added then it won't
599 * have any space until we finish syncing out this txg.
600 * At that point we will consider it initialized and available
601 * for allocations. We also don't consider non-activated
602 * metaslab groups (e.g. vdevs that are in the middle of being removed)
603 * to be initialized, because they can't be used for allocation.
604 */
605 mg->mg_initialized = metaslab_group_initialized(mg);
606 if (!was_initialized && mg->mg_initialized) {
607 mc->mc_groups++;
608 } else if (was_initialized && !mg->mg_initialized) {
609 ASSERT3U(mc->mc_groups, >, 0);
610 mc->mc_groups--;
611 }
612 if (mg->mg_initialized)
613 mg->mg_no_free_space = B_FALSE;
614
615 /*
616 * A metaslab group is considered allocatable if it has plenty
617 * of free space or is not heavily fragmented. We only take
618 * fragmentation into account if the metaslab group has a valid
619 * fragmentation metric (i.e. a value between 0 and 100).
620 */
621 mg->mg_allocatable = (mg->mg_activation_count > 0 &&
622 mg->mg_free_capacity > zfs_mg_noalloc_threshold &&
623 (mg->mg_fragmentation == ZFS_FRAG_INVALID ||
624 mg->mg_fragmentation <= zfs_mg_fragmentation_threshold));
625
626 /*
627 * The mc_alloc_groups maintains a count of the number of
628 * groups in this metaslab class that are still above the
629 * zfs_mg_noalloc_threshold. This is used by the allocating
630 * threads to determine if they should avoid allocations to
631 * a given group. The allocator will avoid allocations to a group
632 * if that group has reached or is below the zfs_mg_noalloc_threshold
633 * and there are still other groups that are above the threshold.
634 * When a group transitions from allocatable to non-allocatable or
635 * vice versa we update the metaslab class to reflect that change.
636 * When the mc_alloc_groups value drops to 0 that means that all
637 * groups have reached the zfs_mg_noalloc_threshold making all groups
638 * eligible for allocations. This effectively means that all devices
639 * are balanced again.
640 */
641 if (was_allocatable && !mg->mg_allocatable)
642 mc->mc_alloc_groups--;
643 else if (!was_allocatable && mg->mg_allocatable)
644 mc->mc_alloc_groups++;
645 mutex_exit(&mc->mc_lock);
646
647 mutex_exit(&mg->mg_lock);
648 }
649
650 metaslab_group_t *
651 metaslab_group_create(metaslab_class_t *mc, vdev_t *vd, int allocators)
652 {
653 metaslab_group_t *mg;
654
655 mg = kmem_zalloc(sizeof (metaslab_group_t), KM_SLEEP);
656 mutex_init(&mg->mg_lock, NULL, MUTEX_DEFAULT, NULL);
657 mutex_init(&mg->mg_ms_initialize_lock, NULL, MUTEX_DEFAULT, NULL);
658 cv_init(&mg->mg_ms_initialize_cv, NULL, CV_DEFAULT, NULL);
659 mg->mg_primaries = kmem_zalloc(allocators * sizeof (metaslab_t *),
660 KM_SLEEP);
661 mg->mg_secondaries = kmem_zalloc(allocators * sizeof (metaslab_t *),
662 KM_SLEEP);
663 avl_create(&mg->mg_metaslab_tree, metaslab_compare,
664 sizeof (metaslab_t), offsetof(struct metaslab, ms_group_node));
665 mg->mg_vd = vd;
666 mg->mg_class = mc;
667 mg->mg_activation_count = 0;
668 mg->mg_initialized = B_FALSE;
669 mg->mg_no_free_space = B_TRUE;
670 mg->mg_allocators = allocators;
671
672 mg->mg_alloc_queue_depth = kmem_zalloc(allocators *
673 sizeof (zfs_refcount_t), KM_SLEEP);
674 mg->mg_cur_max_alloc_queue_depth = kmem_zalloc(allocators *
675 sizeof (uint64_t), KM_SLEEP);
676 for (int i = 0; i < allocators; i++) {
677 zfs_refcount_create_tracked(&mg->mg_alloc_queue_depth[i]);
678 mg->mg_cur_max_alloc_queue_depth[i] = 0;
679 }
680
681 mg->mg_taskq = taskq_create("metaslab_group_taskq", metaslab_load_pct,
682 minclsyspri, 10, INT_MAX, TASKQ_THREADS_CPU_PCT);
683
684 return (mg);
685 }
686
687 void
688 metaslab_group_destroy(metaslab_group_t *mg)
689 {
690 ASSERT(mg->mg_prev == NULL);
691 ASSERT(mg->mg_next == NULL);
692 /*
693 * We may have gone below zero with the activation count
694 * either because we never activated in the first place or
695 * because we're done, and possibly removing the vdev.
696 */
697 ASSERT(mg->mg_activation_count <= 0);
698
699 taskq_destroy(mg->mg_taskq);
700 avl_destroy(&mg->mg_metaslab_tree);
701 kmem_free(mg->mg_primaries, mg->mg_allocators * sizeof (metaslab_t *));
702 kmem_free(mg->mg_secondaries, mg->mg_allocators *
703 sizeof (metaslab_t *));
704 mutex_destroy(&mg->mg_lock);
705 mutex_destroy(&mg->mg_ms_initialize_lock);
706 cv_destroy(&mg->mg_ms_initialize_cv);
707
708 for (int i = 0; i < mg->mg_allocators; i++) {
709 zfs_refcount_destroy(&mg->mg_alloc_queue_depth[i]);
710 mg->mg_cur_max_alloc_queue_depth[i] = 0;
711 }
712 kmem_free(mg->mg_alloc_queue_depth, mg->mg_allocators *
713 sizeof (zfs_refcount_t));
714 kmem_free(mg->mg_cur_max_alloc_queue_depth, mg->mg_allocators *
715 sizeof (uint64_t));
716
717 kmem_free(mg, sizeof (metaslab_group_t));
718 }
719
720 void
721 metaslab_group_activate(metaslab_group_t *mg)
722 {
723 metaslab_class_t *mc = mg->mg_class;
724 metaslab_group_t *mgprev, *mgnext;
725
726 ASSERT3U(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_WRITER), !=, 0);
727
728 ASSERT(mc->mc_rotor != mg);
729 ASSERT(mg->mg_prev == NULL);
730 ASSERT(mg->mg_next == NULL);
731 ASSERT(mg->mg_activation_count <= 0);
732
733 if (++mg->mg_activation_count <= 0)
734 return;
735
736 mg->mg_aliquot = metaslab_aliquot * MAX(1, mg->mg_vd->vdev_children);
737 metaslab_group_alloc_update(mg);
738
739 if ((mgprev = mc->mc_rotor) == NULL) {
740 mg->mg_prev = mg;
741 mg->mg_next = mg;
742 } else {
743 mgnext = mgprev->mg_next;
744 mg->mg_prev = mgprev;
745 mg->mg_next = mgnext;
746 mgprev->mg_next = mg;
747 mgnext->mg_prev = mg;
748 }
749 mc->mc_rotor = mg;
750 }
751
752 /*
753 * Passivate a metaslab group and remove it from the allocation rotor.
754 * Callers must hold both the SCL_ALLOC and SCL_ZIO lock prior to passivating
755 * a metaslab group. This function will momentarily drop spa_config_locks
756 * that are lower than the SCL_ALLOC lock (see comment below).
757 */
758 void
759 metaslab_group_passivate(metaslab_group_t *mg)
760 {
761 metaslab_class_t *mc = mg->mg_class;
762 spa_t *spa = mc->mc_spa;
763 metaslab_group_t *mgprev, *mgnext;
764 int locks = spa_config_held(spa, SCL_ALL, RW_WRITER);
765
766 ASSERT3U(spa_config_held(spa, SCL_ALLOC | SCL_ZIO, RW_WRITER), ==,
767 (SCL_ALLOC | SCL_ZIO));
768
769 if (--mg->mg_activation_count != 0) {
770 ASSERT(mc->mc_rotor != mg);
771 ASSERT(mg->mg_prev == NULL);
772 ASSERT(mg->mg_next == NULL);
773 ASSERT(mg->mg_activation_count < 0);
774 return;
775 }
776
777 /*
778 * The spa_config_lock is an array of rwlocks, ordered as
779 * follows (from highest to lowest):
780 * SCL_CONFIG > SCL_STATE > SCL_L2ARC > SCL_ALLOC >
781 * SCL_ZIO > SCL_FREE > SCL_VDEV
782 * (For more information about the spa_config_lock see spa_misc.c)
783 * The higher the lock, the broader its coverage. When we passivate
784 * a metaslab group, we must hold both the SCL_ALLOC and the SCL_ZIO
785 * config locks. However, the metaslab group's taskq might be trying
786 * to preload metaslabs so we must drop the SCL_ZIO lock and any
787 * lower locks to allow the I/O to complete. At a minimum,
788 * we continue to hold the SCL_ALLOC lock, which prevents any future
789 * allocations from taking place and any changes to the vdev tree.
790 */
791 spa_config_exit(spa, locks & ~(SCL_ZIO - 1), spa);
792 taskq_wait(mg->mg_taskq);
793 spa_config_enter(spa, locks & ~(SCL_ZIO - 1), spa, RW_WRITER);
794 metaslab_group_alloc_update(mg);
795 for (int i = 0; i < mg->mg_allocators; i++) {
796 metaslab_t *msp = mg->mg_primaries[i];
797 if (msp != NULL) {
798 mutex_enter(&msp->ms_lock);
799 metaslab_passivate(msp,
800 metaslab_weight_from_range_tree(msp));
801 mutex_exit(&msp->ms_lock);
802 }
803 msp = mg->mg_secondaries[i];
804 if (msp != NULL) {
805 mutex_enter(&msp->ms_lock);
806 metaslab_passivate(msp,
807 metaslab_weight_from_range_tree(msp));
808 mutex_exit(&msp->ms_lock);
809 }
810 }
811
812 mgprev = mg->mg_prev;
813 mgnext = mg->mg_next;
814
815 if (mg == mgnext) {
816 mc->mc_rotor = NULL;
817 } else {
818 mc->mc_rotor = mgnext;
819 mgprev->mg_next = mgnext;
820 mgnext->mg_prev = mgprev;
821 }
822
823 mg->mg_prev = NULL;
824 mg->mg_next = NULL;
825 }
826
827 boolean_t
828 metaslab_group_initialized(metaslab_group_t *mg)
829 {
830 vdev_t *vd = mg->mg_vd;
831 vdev_stat_t *vs = &vd->vdev_stat;
832
833 return (vs->vs_space != 0 && mg->mg_activation_count > 0);
834 }
835
836 uint64_t
837 metaslab_group_get_space(metaslab_group_t *mg)
838 {
839 return ((1ULL << mg->mg_vd->vdev_ms_shift) * mg->mg_vd->vdev_ms_count);
840 }
841
842 void
843 metaslab_group_histogram_verify(metaslab_group_t *mg)
844 {
845 uint64_t *mg_hist;
846 vdev_t *vd = mg->mg_vd;
847 uint64_t ashift = vd->vdev_ashift;
848 int i;
849
850 if ((zfs_flags & ZFS_DEBUG_HISTOGRAM_VERIFY) == 0)
851 return;
852
853 mg_hist = kmem_zalloc(sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE,
854 KM_SLEEP);
855
856 ASSERT3U(RANGE_TREE_HISTOGRAM_SIZE, >=,
857 SPACE_MAP_HISTOGRAM_SIZE + ashift);
858
859 for (int m = 0; m < vd->vdev_ms_count; m++) {
860 metaslab_t *msp = vd->vdev_ms[m];
861 ASSERT(msp != NULL);
862
863 /* skip if not active or not a member */
864 if (msp->ms_sm == NULL || msp->ms_group != mg)
865 continue;
866
867 for (i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++)
868 mg_hist[i + ashift] +=
869 msp->ms_sm->sm_phys->smp_histogram[i];
870 }
871
872 for (i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i ++)
873 VERIFY3U(mg_hist[i], ==, mg->mg_histogram[i]);
874
875 kmem_free(mg_hist, sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE);
876 }
877
878 static void
879 metaslab_group_histogram_add(metaslab_group_t *mg, metaslab_t *msp)
880 {
881 metaslab_class_t *mc = mg->mg_class;
882 uint64_t ashift = mg->mg_vd->vdev_ashift;
883
884 ASSERT(MUTEX_HELD(&msp->ms_lock));
885 if (msp->ms_sm == NULL)
886 return;
887
888 mutex_enter(&mg->mg_lock);
889 for (int i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++) {
890 mg->mg_histogram[i + ashift] +=
891 msp->ms_sm->sm_phys->smp_histogram[i];
892 mc->mc_histogram[i + ashift] +=
893 msp->ms_sm->sm_phys->smp_histogram[i];
894 }
895 mutex_exit(&mg->mg_lock);
896 }
897
898 void
899 metaslab_group_histogram_remove(metaslab_group_t *mg, metaslab_t *msp)
900 {
901 metaslab_class_t *mc = mg->mg_class;
902 uint64_t ashift = mg->mg_vd->vdev_ashift;
903
904 ASSERT(MUTEX_HELD(&msp->ms_lock));
905 if (msp->ms_sm == NULL)
906 return;
907
908 mutex_enter(&mg->mg_lock);
909 for (int i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++) {
910 ASSERT3U(mg->mg_histogram[i + ashift], >=,
911 msp->ms_sm->sm_phys->smp_histogram[i]);
912 ASSERT3U(mc->mc_histogram[i + ashift], >=,
913 msp->ms_sm->sm_phys->smp_histogram[i]);
914
915 mg->mg_histogram[i + ashift] -=
916 msp->ms_sm->sm_phys->smp_histogram[i];
917 mc->mc_histogram[i + ashift] -=
918 msp->ms_sm->sm_phys->smp_histogram[i];
919 }
920 mutex_exit(&mg->mg_lock);
921 }
922
923 static void
924 metaslab_group_add(metaslab_group_t *mg, metaslab_t *msp)
925 {
926 ASSERT(msp->ms_group == NULL);
927 mutex_enter(&mg->mg_lock);
928 msp->ms_group = mg;
929 msp->ms_weight = 0;
930 avl_add(&mg->mg_metaslab_tree, msp);
931 mutex_exit(&mg->mg_lock);
932
933 mutex_enter(&msp->ms_lock);
934 metaslab_group_histogram_add(mg, msp);
935 mutex_exit(&msp->ms_lock);
936 }
937
938 static void
939 metaslab_group_remove(metaslab_group_t *mg, metaslab_t *msp)
940 {
941 mutex_enter(&msp->ms_lock);
942 metaslab_group_histogram_remove(mg, msp);
943 mutex_exit(&msp->ms_lock);
944
945 mutex_enter(&mg->mg_lock);
946 ASSERT(msp->ms_group == mg);
947 avl_remove(&mg->mg_metaslab_tree, msp);
948 msp->ms_group = NULL;
949 mutex_exit(&mg->mg_lock);
950 }
951
952 static void
953 metaslab_group_sort_impl(metaslab_group_t *mg, metaslab_t *msp, uint64_t weight)
954 {
955 ASSERT(MUTEX_HELD(&mg->mg_lock));
956 ASSERT(msp->ms_group == mg);
957 avl_remove(&mg->mg_metaslab_tree, msp);
958 msp->ms_weight = weight;
959 avl_add(&mg->mg_metaslab_tree, msp);
960
961 }
962
963 static void
964 metaslab_group_sort(metaslab_group_t *mg, metaslab_t *msp, uint64_t weight)
965 {
966 /*
967 * Although in principle the weight can be any value, in
968 * practice we do not use values in the range [1, 511].
969 */
970 ASSERT(weight >= SPA_MINBLOCKSIZE || weight == 0);
971 ASSERT(MUTEX_HELD(&msp->ms_lock));
972
973 mutex_enter(&mg->mg_lock);
974 metaslab_group_sort_impl(mg, msp, weight);
975 mutex_exit(&mg->mg_lock);
976 }
977
978 /*
979 * Calculate the fragmentation for a given metaslab group. We can use
980 * a simple average here since all metaslabs within the group must have
981 * the same size. The return value will be a value between 0 and 100
982 * (inclusive), or ZFS_FRAG_INVALID if less than half of the metaslab in this
983 * group have a fragmentation metric.
984 */
985 uint64_t
986 metaslab_group_fragmentation(metaslab_group_t *mg)
987 {
988 vdev_t *vd = mg->mg_vd;
989 uint64_t fragmentation = 0;
990 uint64_t valid_ms = 0;
991
992 for (int m = 0; m < vd->vdev_ms_count; m++) {
993 metaslab_t *msp = vd->vdev_ms[m];
994
995 if (msp->ms_fragmentation == ZFS_FRAG_INVALID)
996 continue;
997 if (msp->ms_group != mg)
998 continue;
999
1000 valid_ms++;
1001 fragmentation += msp->ms_fragmentation;
1002 }
1003
1004 if (valid_ms <= mg->mg_vd->vdev_ms_count / 2)
1005 return (ZFS_FRAG_INVALID);
1006
1007 fragmentation /= valid_ms;
1008 ASSERT3U(fragmentation, <=, 100);
1009 return (fragmentation);
1010 }
1011
1012 /*
1013 * Determine if a given metaslab group should skip allocations. A metaslab
1014 * group should avoid allocations if its free capacity is less than the
1015 * zfs_mg_noalloc_threshold or its fragmentation metric is greater than
1016 * zfs_mg_fragmentation_threshold and there is at least one metaslab group
1017 * that can still handle allocations. If the allocation throttle is enabled
1018 * then we skip allocations to devices that have reached their maximum
1019 * allocation queue depth unless the selected metaslab group is the only
1020 * eligible group remaining.
1021 */
1022 static boolean_t
1023 metaslab_group_allocatable(metaslab_group_t *mg, metaslab_group_t *rotor,
1024 uint64_t psize, int allocator)
1025 {
1026 spa_t *spa = mg->mg_vd->vdev_spa;
1027 metaslab_class_t *mc = mg->mg_class;
1028
1029 /*
1030 * We can only consider skipping this metaslab group if it's
1031 * in the normal metaslab class and there are other metaslab
1032 * groups to select from. Otherwise, we always consider it eligible
1033 * for allocations.
1034 */
1035 if ((mc != spa_normal_class(spa) &&
1036 mc != spa_special_class(spa) &&
1037 mc != spa_dedup_class(spa)) ||
1038 mc->mc_groups <= 1)
1039 return (B_TRUE);
1040
1041 /*
1042 * If the metaslab group's mg_allocatable flag is set (see comments
1043 * in metaslab_group_alloc_update() for more information) and
1044 * the allocation throttle is disabled then allow allocations to this
1045 * device. However, if the allocation throttle is enabled then
1046 * check if we have reached our allocation limit (mg_alloc_queue_depth)
1047 * to determine if we should allow allocations to this metaslab group.
1048 * If all metaslab groups are no longer considered allocatable
1049 * (mc_alloc_groups == 0) or we're trying to allocate the smallest
1050 * gang block size then we allow allocations on this metaslab group
1051 * regardless of the mg_allocatable or throttle settings.
1052 */
1053 if (mg->mg_allocatable) {
1054 metaslab_group_t *mgp;
1055 int64_t qdepth;
1056 uint64_t qmax = mg->mg_cur_max_alloc_queue_depth[allocator];
1057
1058 if (!mc->mc_alloc_throttle_enabled)
1059 return (B_TRUE);
1060
1061 /*
1062 * If this metaslab group does not have any free space, then
1063 * there is no point in looking further.
1064 */
1065 if (mg->mg_no_free_space)
1066 return (B_FALSE);
1067
1068 qdepth = zfs_refcount_count(
1069 &mg->mg_alloc_queue_depth[allocator]);
1070
1071 /*
1072 * If this metaslab group is below its qmax or it's
1073 * the only allocatable metasable group, then attempt
1074 * to allocate from it.
1075 */
1076 if (qdepth < qmax || mc->mc_alloc_groups == 1)
1077 return (B_TRUE);
1078 ASSERT3U(mc->mc_alloc_groups, >, 1);
1079
1080 /*
1081 * Since this metaslab group is at or over its qmax, we
1082 * need to determine if there are metaslab groups after this
1083 * one that might be able to handle this allocation. This is
1084 * racy since we can't hold the locks for all metaslab
1085 * groups at the same time when we make this check.
1086 */
1087 for (mgp = mg->mg_next; mgp != rotor; mgp = mgp->mg_next) {
1088 qmax = mgp->mg_cur_max_alloc_queue_depth[allocator];
1089
1090 qdepth = zfs_refcount_count(
1091 &mgp->mg_alloc_queue_depth[allocator]);
1092
1093 /*
1094 * If there is another metaslab group that
1095 * might be able to handle the allocation, then
1096 * we return false so that we skip this group.
1097 */
1098 if (qdepth < qmax && !mgp->mg_no_free_space)
1099 return (B_FALSE);
1100 }
1101
1102 /*
1103 * We didn't find another group to handle the allocation
1104 * so we can't skip this metaslab group even though
1105 * we are at or over our qmax.
1106 */
1107 return (B_TRUE);
1108
1109 } else if (mc->mc_alloc_groups == 0 || psize == SPA_MINBLOCKSIZE) {
1110 return (B_TRUE);
1111 }
1112 return (B_FALSE);
1113 }
1114
1115 /*
1116 * ==========================================================================
1117 * Range tree callbacks
1118 * ==========================================================================
1119 */
1120
1121 /*
1122 * Comparison function for the private size-ordered tree. Tree is sorted
1123 * by size, larger sizes at the end of the tree.
1124 */
1125 static int
1126 metaslab_rangesize_compare(const void *x1, const void *x2)
1127 {
1128 const range_seg_t *r1 = x1;
1129 const range_seg_t *r2 = x2;
1130 uint64_t rs_size1 = r1->rs_end - r1->rs_start;
1131 uint64_t rs_size2 = r2->rs_end - r2->rs_start;
1132
1133 if (rs_size1 < rs_size2)
1134 return (-1);
1135 if (rs_size1 > rs_size2)
1136 return (1);
1137
1138 if (r1->rs_start < r2->rs_start)
1139 return (-1);
1140
1141 if (r1->rs_start > r2->rs_start)
1142 return (1);
1143
1144 return (0);
1145 }
1146
1147 /*
1148 * Create any block allocator specific components. The current allocators
1149 * rely on using both a size-ordered range_tree_t and an array of uint64_t's.
1150 */
1151 static void
1152 metaslab_rt_create(range_tree_t *rt, void *arg)
1153 {
1154 metaslab_t *msp = arg;
1155
1156 ASSERT3P(rt->rt_arg, ==, msp);
1157 ASSERT(msp->ms_allocatable == NULL);
1158
1159 avl_create(&msp->ms_allocatable_by_size, metaslab_rangesize_compare,
1160 sizeof (range_seg_t), offsetof(range_seg_t, rs_pp_node));
1161 }
1162
1163 /*
1164 * Destroy the block allocator specific components.
1165 */
1166 static void
1167 metaslab_rt_destroy(range_tree_t *rt, void *arg)
1168 {
1169 metaslab_t *msp = arg;
1170
1171 ASSERT3P(rt->rt_arg, ==, msp);
1172 ASSERT3P(msp->ms_allocatable, ==, rt);
1173 ASSERT0(avl_numnodes(&msp->ms_allocatable_by_size));
1174
1175 avl_destroy(&msp->ms_allocatable_by_size);
1176 }
1177
1178 static void
1179 metaslab_rt_add(range_tree_t *rt, range_seg_t *rs, void *arg)
1180 {
1181 metaslab_t *msp = arg;
1182
1183 ASSERT3P(rt->rt_arg, ==, msp);
1184 ASSERT3P(msp->ms_allocatable, ==, rt);
1185 VERIFY(!msp->ms_condensing);
1186 avl_add(&msp->ms_allocatable_by_size, rs);
1187 }
1188
1189 static void
1190 metaslab_rt_remove(range_tree_t *rt, range_seg_t *rs, void *arg)
1191 {
1192 metaslab_t *msp = arg;
1193
1194 ASSERT3P(rt->rt_arg, ==, msp);
1195 ASSERT3P(msp->ms_allocatable, ==, rt);
1196 VERIFY(!msp->ms_condensing);
1197 avl_remove(&msp->ms_allocatable_by_size, rs);
1198 }
1199
1200 static void
1201 metaslab_rt_vacate(range_tree_t *rt, void *arg)
1202 {
1203 metaslab_t *msp = arg;
1204
1205 ASSERT3P(rt->rt_arg, ==, msp);
1206 ASSERT3P(msp->ms_allocatable, ==, rt);
1207
1208 /*
1209 * Normally one would walk the tree freeing nodes along the way.
1210 * Since the nodes are shared with the range trees we can avoid
1211 * walking all nodes and just reinitialize the avl tree. The nodes
1212 * will be freed by the range tree, so we don't want to free them here.
1213 */
1214 avl_create(&msp->ms_allocatable_by_size, metaslab_rangesize_compare,
1215 sizeof (range_seg_t), offsetof(range_seg_t, rs_pp_node));
1216 }
1217
1218 static range_tree_ops_t metaslab_rt_ops = {
1219 metaslab_rt_create,
1220 metaslab_rt_destroy,
1221 metaslab_rt_add,
1222 metaslab_rt_remove,
1223 metaslab_rt_vacate
1224 };
1225
1226 /*
1227 * ==========================================================================
1228 * Common allocator routines
1229 * ==========================================================================
1230 */
1231
1232 /*
1233 * Return the maximum contiguous segment within the metaslab.
1234 */
1235 uint64_t
1236 metaslab_block_maxsize(metaslab_t *msp)
1237 {
1238 avl_tree_t *t = &msp->ms_allocatable_by_size;
1239 range_seg_t *rs;
1240
1241 if (t == NULL || (rs = avl_last(t)) == NULL)
1242 return (0ULL);
1243
1244 return (rs->rs_end - rs->rs_start);
1245 }
1246
1247 static range_seg_t *
1248 metaslab_block_find(avl_tree_t *t, uint64_t start, uint64_t size)
1249 {
1250 range_seg_t *rs, rsearch;
1251 avl_index_t where;
1252
1253 rsearch.rs_start = start;
1254 rsearch.rs_end = start + size;
1255
1256 rs = avl_find(t, &rsearch, &where);
1257 if (rs == NULL) {
1258 rs = avl_nearest(t, where, AVL_AFTER);
1259 }
1260
1261 return (rs);
1262 }
1263
1264 /*
1265 * This is a helper function that can be used by the allocator to find
1266 * a suitable block to allocate. This will search the specified AVL
1267 * tree looking for a block that matches the specified criteria.
1268 */
1269 static uint64_t
1270 metaslab_block_picker(avl_tree_t *t, uint64_t *cursor, uint64_t size,
1271 uint64_t align)
1272 {
1273 range_seg_t *rs = metaslab_block_find(t, *cursor, size);
1274
1275 while (rs != NULL) {
1276 uint64_t offset = P2ROUNDUP(rs->rs_start, align);
1277
1278 if (offset + size <= rs->rs_end) {
1279 *cursor = offset + size;
1280 return (offset);
1281 }
1282 rs = AVL_NEXT(t, rs);
1283 }
1284
1285 /*
1286 * If we know we've searched the whole map (*cursor == 0), give up.
1287 * Otherwise, reset the cursor to the beginning and try again.
1288 */
1289 if (*cursor == 0)
1290 return (-1ULL);
1291
1292 *cursor = 0;
1293 return (metaslab_block_picker(t, cursor, size, align));
1294 }
1295
1296 /*
1297 * ==========================================================================
1298 * The first-fit block allocator
1299 * ==========================================================================
1300 */
1301 static uint64_t
1302 metaslab_ff_alloc(metaslab_t *msp, uint64_t size)
1303 {
1304 /*
1305 * Find the largest power of 2 block size that evenly divides the
1306 * requested size. This is used to try to allocate blocks with similar
1307 * alignment from the same area of the metaslab (i.e. same cursor
1308 * bucket) but it does not guarantee that other allocations sizes
1309 * may exist in the same region.
1310 */
1311 uint64_t align = size & -size;
1312 uint64_t *cursor = &msp->ms_lbas[highbit64(align) - 1];
1313 avl_tree_t *t = &msp->ms_allocatable->rt_root;
1314
1315 return (metaslab_block_picker(t, cursor, size, align));
1316 }
1317
1318 static metaslab_ops_t metaslab_ff_ops = {
1319 metaslab_ff_alloc
1320 };
1321
1322 /*
1323 * ==========================================================================
1324 * Dynamic block allocator -
1325 * Uses the first fit allocation scheme until space get low and then
1326 * adjusts to a best fit allocation method. Uses metaslab_df_alloc_threshold
1327 * and metaslab_df_free_pct to determine when to switch the allocation scheme.
1328 * ==========================================================================
1329 */
1330 static uint64_t
1331 metaslab_df_alloc(metaslab_t *msp, uint64_t size)
1332 {
1333 /*
1334 * Find the largest power of 2 block size that evenly divides the
1335 * requested size. This is used to try to allocate blocks with similar
1336 * alignment from the same area of the metaslab (i.e. same cursor
1337 * bucket) but it does not guarantee that other allocations sizes
1338 * may exist in the same region.
1339 */
1340 uint64_t align = size & -size;
1341 uint64_t *cursor = &msp->ms_lbas[highbit64(align) - 1];
1342 range_tree_t *rt = msp->ms_allocatable;
1343 avl_tree_t *t = &rt->rt_root;
1344 uint64_t max_size = metaslab_block_maxsize(msp);
1345 int free_pct = range_tree_space(rt) * 100 / msp->ms_size;
1346
1347 ASSERT(MUTEX_HELD(&msp->ms_lock));
1348 ASSERT3U(avl_numnodes(t), ==,
1349 avl_numnodes(&msp->ms_allocatable_by_size));
1350
1351 if (max_size < size)
1352 return (-1ULL);
1353
1354 /*
1355 * If we're running low on space switch to using the size
1356 * sorted AVL tree (best-fit).
1357 */
1358 if (max_size < metaslab_df_alloc_threshold ||
1359 free_pct < metaslab_df_free_pct) {
1360 t = &msp->ms_allocatable_by_size;
1361 *cursor = 0;
1362 }
1363
1364 return (metaslab_block_picker(t, cursor, size, 1ULL));
1365 }
1366
1367 static metaslab_ops_t metaslab_df_ops = {
1368 metaslab_df_alloc
1369 };
1370
1371 /*
1372 * ==========================================================================
1373 * Cursor fit block allocator -
1374 * Select the largest region in the metaslab, set the cursor to the beginning
1375 * of the range and the cursor_end to the end of the range. As allocations
1376 * are made advance the cursor. Continue allocating from the cursor until
1377 * the range is exhausted and then find a new range.
1378 * ==========================================================================
1379 */
1380 static uint64_t
1381 metaslab_cf_alloc(metaslab_t *msp, uint64_t size)
1382 {
1383 range_tree_t *rt = msp->ms_allocatable;
1384 avl_tree_t *t = &msp->ms_allocatable_by_size;
1385 uint64_t *cursor = &msp->ms_lbas[0];
1386 uint64_t *cursor_end = &msp->ms_lbas[1];
1387 uint64_t offset = 0;
1388
1389 ASSERT(MUTEX_HELD(&msp->ms_lock));
1390 ASSERT3U(avl_numnodes(t), ==, avl_numnodes(&rt->rt_root));
1391
1392 ASSERT3U(*cursor_end, >=, *cursor);
1393
1394 if ((*cursor + size) > *cursor_end) {
1395 range_seg_t *rs;
1396
1397 rs = avl_last(&msp->ms_allocatable_by_size);
1398 if (rs == NULL || (rs->rs_end - rs->rs_start) < size)
1399 return (-1ULL);
1400
1401 *cursor = rs->rs_start;
1402 *cursor_end = rs->rs_end;
1403 }
1404
1405 offset = *cursor;
1406 *cursor += size;
1407
1408 return (offset);
1409 }
1410
1411 static metaslab_ops_t metaslab_cf_ops = {
1412 metaslab_cf_alloc
1413 };
1414
1415 /*
1416 * ==========================================================================
1417 * New dynamic fit allocator -
1418 * Select a region that is large enough to allocate 2^metaslab_ndf_clump_shift
1419 * contiguous blocks. If no region is found then just use the largest segment
1420 * that remains.
1421 * ==========================================================================
1422 */
1423
1424 /*
1425 * Determines desired number of contiguous blocks (2^metaslab_ndf_clump_shift)
1426 * to request from the allocator.
1427 */
1428 uint64_t metaslab_ndf_clump_shift = 4;
1429
1430 static uint64_t
1431 metaslab_ndf_alloc(metaslab_t *msp, uint64_t size)
1432 {
1433 avl_tree_t *t = &msp->ms_allocatable->rt_root;
1434 avl_index_t where;
1435 range_seg_t *rs, rsearch;
1436 uint64_t hbit = highbit64(size);
1437 uint64_t *cursor = &msp->ms_lbas[hbit - 1];
1438 uint64_t max_size = metaslab_block_maxsize(msp);
1439
1440 ASSERT(MUTEX_HELD(&msp->ms_lock));
1441 ASSERT3U(avl_numnodes(t), ==,
1442 avl_numnodes(&msp->ms_allocatable_by_size));
1443
1444 if (max_size < size)
1445 return (-1ULL);
1446
1447 rsearch.rs_start = *cursor;
1448 rsearch.rs_end = *cursor + size;
1449
1450 rs = avl_find(t, &rsearch, &where);
1451 if (rs == NULL || (rs->rs_end - rs->rs_start) < size) {
1452 t = &msp->ms_allocatable_by_size;
1453
1454 rsearch.rs_start = 0;
1455 rsearch.rs_end = MIN(max_size,
1456 1ULL << (hbit + metaslab_ndf_clump_shift));
1457 rs = avl_find(t, &rsearch, &where);
1458 if (rs == NULL)
1459 rs = avl_nearest(t, where, AVL_AFTER);
1460 ASSERT(rs != NULL);
1461 }
1462
1463 if ((rs->rs_end - rs->rs_start) >= size) {
1464 *cursor = rs->rs_start + size;
1465 return (rs->rs_start);
1466 }
1467 return (-1ULL);
1468 }
1469
1470 static metaslab_ops_t metaslab_ndf_ops = {
1471 metaslab_ndf_alloc
1472 };
1473
1474 metaslab_ops_t *zfs_metaslab_ops = &metaslab_df_ops;
1475
1476 /*
1477 * ==========================================================================
1478 * Metaslabs
1479 * ==========================================================================
1480 */
1481
1482 static void
1483 metaslab_aux_histograms_clear(metaslab_t *msp)
1484 {
1485 /*
1486 * Auxiliary histograms are only cleared when resetting them,
1487 * which can only happen while the metaslab is loaded.
1488 */
1489 ASSERT(msp->ms_loaded);
1490
1491 bzero(msp->ms_synchist, sizeof (msp->ms_synchist));
1492 for (int t = 0; t < TXG_DEFER_SIZE; t++)
1493 bzero(msp->ms_deferhist[t], sizeof (msp->ms_deferhist[t]));
1494 }
1495
1496 static void
1497 metaslab_aux_histogram_add(uint64_t *histogram, uint64_t shift,
1498 range_tree_t *rt)
1499 {
1500 /*
1501 * This is modeled after space_map_histogram_add(), so refer to that
1502 * function for implementation details. We want this to work like
1503 * the space map histogram, and not the range tree histogram, as we
1504 * are essentially constructing a delta that will be later subtracted
1505 * from the space map histogram.
1506 */
1507 int idx = 0;
1508 for (int i = shift; i < RANGE_TREE_HISTOGRAM_SIZE; i++) {
1509 ASSERT3U(i, >=, idx + shift);
1510 histogram[idx] += rt->rt_histogram[i] << (i - idx - shift);
1511
1512 if (idx < SPACE_MAP_HISTOGRAM_SIZE - 1) {
1513 ASSERT3U(idx + shift, ==, i);
1514 idx++;
1515 ASSERT3U(idx, <, SPACE_MAP_HISTOGRAM_SIZE);
1516 }
1517 }
1518 }
1519
1520 /*
1521 * Called at every sync pass that the metaslab gets synced.
1522 *
1523 * The reason is that we want our auxiliary histograms to be updated
1524 * wherever the metaslab's space map histogram is updated. This way
1525 * we stay consistent on which parts of the metaslab space map's
1526 * histogram are currently not available for allocations (e.g because
1527 * they are in the defer, freed, and freeing trees).
1528 */
1529 static void
1530 metaslab_aux_histograms_update(metaslab_t *msp)
1531 {
1532 space_map_t *sm = msp->ms_sm;
1533 ASSERT(sm != NULL);
1534
1535 /*
1536 * This is similar to the metaslab's space map histogram updates
1537 * that take place in metaslab_sync(). The only difference is that
1538 * we only care about segments that haven't made it into the
1539 * ms_allocatable tree yet.
1540 */
1541 if (msp->ms_loaded) {
1542 metaslab_aux_histograms_clear(msp);
1543
1544 metaslab_aux_histogram_add(msp->ms_synchist,
1545 sm->sm_shift, msp->ms_freed);
1546
1547 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
1548 metaslab_aux_histogram_add(msp->ms_deferhist[t],
1549 sm->sm_shift, msp->ms_defer[t]);
1550 }
1551 }
1552
1553 metaslab_aux_histogram_add(msp->ms_synchist,
1554 sm->sm_shift, msp->ms_freeing);
1555 }
1556
1557 /*
1558 * Called every time we are done syncing (writing to) the metaslab,
1559 * i.e. at the end of each sync pass.
1560 * [see the comment in metaslab_impl.h for ms_synchist, ms_deferhist]
1561 */
1562 static void
1563 metaslab_aux_histograms_update_done(metaslab_t *msp, boolean_t defer_allowed)
1564 {
1565 spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
1566 space_map_t *sm = msp->ms_sm;
1567
1568 if (sm == NULL) {
1569 /*
1570 * We came here from metaslab_init() when creating/opening a
1571 * pool, looking at a metaslab that hasn't had any allocations
1572 * yet.
1573 */
1574 return;
1575 }
1576
1577 /*
1578 * This is similar to the actions that we take for the ms_freed
1579 * and ms_defer trees in metaslab_sync_done().
1580 */
1581 uint64_t hist_index = spa_syncing_txg(spa) % TXG_DEFER_SIZE;
1582 if (defer_allowed) {
1583 bcopy(msp->ms_synchist, msp->ms_deferhist[hist_index],
1584 sizeof (msp->ms_synchist));
1585 } else {
1586 bzero(msp->ms_deferhist[hist_index],
1587 sizeof (msp->ms_deferhist[hist_index]));
1588 }
1589 bzero(msp->ms_synchist, sizeof (msp->ms_synchist));
1590 }
1591
1592 /*
1593 * Ensure that the metaslab's weight and fragmentation are consistent
1594 * with the contents of the histogram (either the range tree's histogram
1595 * or the space map's depending whether the metaslab is loaded).
1596 */
1597 static void
1598 metaslab_verify_weight_and_frag(metaslab_t *msp)
1599 {
1600 ASSERT(MUTEX_HELD(&msp->ms_lock));
1601
1602 if ((zfs_flags & ZFS_DEBUG_METASLAB_VERIFY) == 0)
1603 return;
1604
1605 /* see comment in metaslab_verify_unflushed_changes() */
1606 if (msp->ms_group == NULL)
1607 return;
1608
1609 /*
1610 * Devices being removed always return a weight of 0 and leave
1611 * fragmentation and ms_max_size as is - there is nothing for
1612 * us to verify here.
1613 */
1614 vdev_t *vd = msp->ms_group->mg_vd;
1615 if (vd->vdev_removing)
1616 return;
1617
1618 /*
1619 * If the metaslab is dirty it probably means that we've done
1620 * some allocations or frees that have changed our histograms
1621 * and thus the weight.
1622 */
1623 for (int t = 0; t < TXG_SIZE; t++) {
1624 if (txg_list_member(&vd->vdev_ms_list, msp, t))
1625 return;
1626 }
1627
1628 /*
1629 * This verification checks that our in-memory state is consistent
1630 * with what's on disk. If the pool is read-only then there aren't
1631 * any changes and we just have the initially-loaded state.
1632 */
1633 if (!spa_writeable(msp->ms_group->mg_vd->vdev_spa))
1634 return;
1635
1636 /* some extra verification for in-core tree if you can */
1637 if (msp->ms_loaded) {
1638 range_tree_stat_verify(msp->ms_allocatable);
1639 VERIFY(space_map_histogram_verify(msp->ms_sm,
1640 msp->ms_allocatable));
1641 }
1642
1643 uint64_t weight = msp->ms_weight;
1644 uint64_t was_active = msp->ms_weight & METASLAB_ACTIVE_MASK;
1645 boolean_t space_based = WEIGHT_IS_SPACEBASED(msp->ms_weight);
1646 uint64_t frag = msp->ms_fragmentation;
1647 uint64_t max_segsize = msp->ms_max_size;
1648
1649 msp->ms_weight = 0;
1650 msp->ms_fragmentation = 0;
1651 msp->ms_max_size = 0;
1652
1653 /*
1654 * This function is used for verification purposes. Regardless of
1655 * whether metaslab_weight() thinks this metaslab should be active or
1656 * not, we want to ensure that the actual weight (and therefore the
1657 * value of ms_weight) would be the same if it was to be recalculated
1658 * at this point.
1659 */
1660 msp->ms_weight = metaslab_weight(msp) | was_active;
1661
1662 VERIFY3U(max_segsize, ==, msp->ms_max_size);
1663
1664 /*
1665 * If the weight type changed then there is no point in doing
1666 * verification. Revert fields to their original values.
1667 */
1668 if ((space_based && !WEIGHT_IS_SPACEBASED(msp->ms_weight)) ||
1669 (!space_based && WEIGHT_IS_SPACEBASED(msp->ms_weight))) {
1670 msp->ms_fragmentation = frag;
1671 msp->ms_weight = weight;
1672 return;
1673 }
1674
1675 VERIFY3U(msp->ms_fragmentation, ==, frag);
1676 VERIFY3U(msp->ms_weight, ==, weight);
1677 }
1678
1679 /*
1680 * Wait for any in-progress metaslab loads to complete.
1681 */
1682 static void
1683 metaslab_load_wait(metaslab_t *msp)
1684 {
1685 ASSERT(MUTEX_HELD(&msp->ms_lock));
1686
1687 while (msp->ms_loading) {
1688 ASSERT(!msp->ms_loaded);
1689 cv_wait(&msp->ms_load_cv, &msp->ms_lock);
1690 }
1691 }
1692
1693 static int
1694 metaslab_load_impl(metaslab_t *msp)
1695 {
1696 int error = 0;
1697
1698 ASSERT(MUTEX_HELD(&msp->ms_lock));
1699 ASSERT(msp->ms_loading);
1700 ASSERT(!msp->ms_condensing);
1701
1702 /*
1703 * We temporarily drop the lock to unblock other operations while we
1704 * are reading the space map. Therefore, metaslab_sync() and
1705 * metaslab_sync_done() can run at the same time as we do.
1706 *
1707 * metaslab_sync() can append to the space map while we are loading.
1708 * Therefore we load only entries that existed when we started the
1709 * load. Additionally, metaslab_sync_done() has to wait for the load
1710 * to complete because there are potential races like metaslab_load()
1711 * loading parts of the space map that are currently being appended
1712 * by metaslab_sync(). If we didn't, the ms_allocatable would have
1713 * entries that metaslab_sync_done() would try to re-add later.
1714 *
1715 * That's why before dropping the lock we remember the synced length
1716 * of the metaslab and read up to that point of the space map,
1717 * ignoring entries appended by metaslab_sync() that happen after we
1718 * drop the lock.
1719 */
1720 uint64_t length = msp->ms_synced_length;
1721 mutex_exit(&msp->ms_lock);
1722
1723 if (msp->ms_sm != NULL) {
1724 error = space_map_load_length(msp->ms_sm, msp->ms_allocatable,
1725 SM_FREE, length);
1726 } else {
1727 /*
1728 * The space map has not been allocated yet, so treat
1729 * all the space in the metaslab as free and add it to the
1730 * ms_allocatable tree.
1731 */
1732 range_tree_add(msp->ms_allocatable,
1733 msp->ms_start, msp->ms_size);
1734 }
1735
1736 /*
1737 * We need to grab the ms_sync_lock to prevent metaslab_sync() from
1738 * changing the ms_sm and the metaslab's range trees while we are
1739 * about to use them and populate the ms_allocatable. The ms_lock
1740 * is insufficient for this because metaslab_sync() doesn't hold
1741 * the ms_lock while writing the ms_checkpointing tree to disk.
1742 */
1743 mutex_enter(&msp->ms_sync_lock);
1744 mutex_enter(&msp->ms_lock);
1745 ASSERT(!msp->ms_condensing);
1746
1747 if (error != 0) {
1748 mutex_exit(&msp->ms_sync_lock);
1749 return (error);
1750 }
1751
1752 ASSERT3P(msp->ms_group, !=, NULL);
1753 msp->ms_loaded = B_TRUE;
1754
1755 /*
1756 * The ms_allocatable contains the segments that exist in the
1757 * ms_defer trees [see ms_synced_length]. Thus we need to remove
1758 * them from ms_allocatable as they will be added again in
1759 * metaslab_sync_done().
1760 */
1761 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
1762 range_tree_walk(msp->ms_defer[t],
1763 range_tree_remove, msp->ms_allocatable);
1764 }
1765
1766 /*
1767 * Call metaslab_recalculate_weight_and_sort() now that the
1768 * metaslab is loaded so we get the metaslab's real weight.
1769 *
1770 * Unless this metaslab was created with older software and
1771 * has not yet been converted to use segment-based weight, we
1772 * expect the new weight to be better or equal to the weight
1773 * that the metaslab had while it was not loaded. This is
1774 * because the old weight does not take into account the
1775 * consolidation of adjacent segments between TXGs. [see
1776 * comment for ms_synchist and ms_deferhist[] for more info]
1777 */
1778 uint64_t weight = msp->ms_weight;
1779 metaslab_recalculate_weight_and_sort(msp);
1780 if (!WEIGHT_IS_SPACEBASED(weight))
1781 ASSERT3U(weight, <=, msp->ms_weight);
1782 msp->ms_max_size = metaslab_block_maxsize(msp);
1783
1784 spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
1785 metaslab_verify_space(msp, spa_syncing_txg(spa));
1786 mutex_exit(&msp->ms_sync_lock);
1787
1788 return (0);
1789 }
1790
1791 int
1792 metaslab_load(metaslab_t *msp)
1793 {
1794 ASSERT(MUTEX_HELD(&msp->ms_lock));
1795
1796 /*
1797 * There may be another thread loading the same metaslab, if that's
1798 * the case just wait until the other thread is done and return.
1799 */
1800 metaslab_load_wait(msp);
1801 if (msp->ms_loaded)
1802 return (0);
1803 VERIFY(!msp->ms_loading);
1804 ASSERT(!msp->ms_condensing);
1805
1806 msp->ms_loading = B_TRUE;
1807 int error = metaslab_load_impl(msp);
1808 msp->ms_loading = B_FALSE;
1809 cv_broadcast(&msp->ms_load_cv);
1810
1811 return (error);
1812 }
1813
1814 void
1815 metaslab_unload(metaslab_t *msp)
1816 {
1817 ASSERT(MUTEX_HELD(&msp->ms_lock));
1818
1819 metaslab_verify_weight_and_frag(msp);
1820
1821 range_tree_vacate(msp->ms_allocatable, NULL, NULL);
1822 msp->ms_loaded = B_FALSE;
1823
1824 msp->ms_weight &= ~METASLAB_ACTIVE_MASK;
1825 msp->ms_max_size = 0;
1826
1827 /*
1828 * We explicitly recalculate the metaslab's weight based on its space
1829 * map (as it is now not loaded). We want unload metaslabs to always
1830 * have their weights calculated from the space map histograms, while
1831 * loaded ones have it calculated from their in-core range tree
1832 * [see metaslab_load()]. This way, the weight reflects the information
1833 * available in-core, whether it is loaded or not
1834 *
1835 * If ms_group == NULL means that we came here from metaslab_fini(),
1836 * at which point it doesn't make sense for us to do the recalculation
1837 * and the sorting.
1838 */
1839 if (msp->ms_group != NULL)
1840 metaslab_recalculate_weight_and_sort(msp);
1841 }
1842
1843 static void
1844 metaslab_space_update(vdev_t *vd, metaslab_class_t *mc, int64_t alloc_delta,
1845 int64_t defer_delta, int64_t space_delta)
1846 {
1847 vdev_space_update(vd, alloc_delta, defer_delta, space_delta);
1848
1849 ASSERT3P(vd->vdev_spa->spa_root_vdev, ==, vd->vdev_parent);
1850 ASSERT(vd->vdev_ms_count != 0);
1851
1852 metaslab_class_space_update(mc, alloc_delta, defer_delta, space_delta,
1853 vdev_deflated_space(vd, space_delta));
1854 }
1855
1856 int
1857 metaslab_init(metaslab_group_t *mg, uint64_t id, uint64_t object, uint64_t txg,
1858 metaslab_t **msp)
1859 {
1860 vdev_t *vd = mg->mg_vd;
1861 spa_t *spa = vd->vdev_spa;
1862 objset_t *mos = spa->spa_meta_objset;
1863 metaslab_t *ms;
1864 int error;
1865
1866 ms = kmem_zalloc(sizeof (metaslab_t), KM_SLEEP);
1867 mutex_init(&ms->ms_lock, NULL, MUTEX_DEFAULT, NULL);
1868 mutex_init(&ms->ms_sync_lock, NULL, MUTEX_DEFAULT, NULL);
1869 cv_init(&ms->ms_load_cv, NULL, CV_DEFAULT, NULL);
1870
1871 ms->ms_id = id;
1872 ms->ms_start = id << vd->vdev_ms_shift;
1873 ms->ms_size = 1ULL << vd->vdev_ms_shift;
1874 ms->ms_allocator = -1;
1875 ms->ms_new = B_TRUE;
1876
1877 /*
1878 * We only open space map objects that already exist. All others
1879 * will be opened when we finally allocate an object for it.
1880 *
1881 * Note:
1882 * When called from vdev_expand(), we can't call into the DMU as
1883 * we are holding the spa_config_lock as a writer and we would
1884 * deadlock [see relevant comment in vdev_metaslab_init()]. in
1885 * that case, the object parameter is zero though, so we won't
1886 * call into the DMU.
1887 */
1888 if (object != 0) {
1889 error = space_map_open(&ms->ms_sm, mos, object, ms->ms_start,
1890 ms->ms_size, vd->vdev_ashift);
1891
1892 if (error != 0) {
1893 kmem_free(ms, sizeof (metaslab_t));
1894 return (error);
1895 }
1896
1897 ASSERT(ms->ms_sm != NULL);
1898 ASSERT3S(space_map_allocated(ms->ms_sm), >=, 0);
1899 ms->ms_allocated_space = space_map_allocated(ms->ms_sm);
1900 }
1901
1902 /*
1903 * We create the ms_allocatable here, but we don't create the
1904 * other range trees until metaslab_sync_done(). This serves
1905 * two purposes: it allows metaslab_sync_done() to detect the
1906 * addition of new space; and for debugging, it ensures that
1907 * we'd data fault on any attempt to use this metaslab before
1908 * it's ready.
1909 */
1910 ms->ms_allocatable = range_tree_create(&metaslab_rt_ops, ms);
1911 metaslab_group_add(mg, ms);
1912
1913 metaslab_set_fragmentation(ms);
1914
1915 /*
1916 * If we're opening an existing pool (txg == 0) or creating
1917 * a new one (txg == TXG_INITIAL), all space is available now.
1918 * If we're adding space to an existing pool, the new space
1919 * does not become available until after this txg has synced.
1920 * The metaslab's weight will also be initialized when we sync
1921 * out this txg. This ensures that we don't attempt to allocate
1922 * from it before we have initialized it completely.
1923 */
1924 if (txg <= TXG_INITIAL) {
1925 metaslab_sync_done(ms, 0);
1926 metaslab_space_update(vd, mg->mg_class,
1927 metaslab_allocated_space(ms), 0, 0);
1928 }
1929
1930 /*
1931 * If metaslab_debug_load is set and we're initializing a metaslab
1932 * that has an allocated space map object then load the space map
1933 * so that we can verify frees.
1934 */
1935 if (metaslab_debug_load && ms->ms_sm != NULL) {
1936 mutex_enter(&ms->ms_lock);
1937 VERIFY0(metaslab_load(ms));
1938 mutex_exit(&ms->ms_lock);
1939 }
1940
1941 if (txg != 0) {
1942 vdev_dirty(vd, 0, NULL, txg);
1943 vdev_dirty(vd, VDD_METASLAB, ms, txg);
1944 }
1945
1946 *msp = ms;
1947
1948 return (0);
1949 }
1950
1951 void
1952 metaslab_fini(metaslab_t *msp)
1953 {
1954 metaslab_group_t *mg = msp->ms_group;
1955 vdev_t *vd = mg->mg_vd;
1956
1957 metaslab_group_remove(mg, msp);
1958
1959 mutex_enter(&msp->ms_lock);
1960 VERIFY(msp->ms_group == NULL);
1961 metaslab_space_update(vd, mg->mg_class,
1962 -metaslab_allocated_space(msp), 0, -msp->ms_size);
1963
1964 space_map_close(msp->ms_sm);
1965
1966 metaslab_unload(msp);
1967
1968 range_tree_destroy(msp->ms_allocatable);
1969 range_tree_destroy(msp->ms_freeing);
1970 range_tree_destroy(msp->ms_freed);
1971
1972 for (int t = 0; t < TXG_SIZE; t++) {
1973 range_tree_destroy(msp->ms_allocating[t]);
1974 }
1975
1976 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
1977 range_tree_destroy(msp->ms_defer[t]);
1978 }
1979 ASSERT0(msp->ms_deferspace);
1980
1981 range_tree_destroy(msp->ms_checkpointing);
1982
1983 for (int t = 0; t < TXG_SIZE; t++)
1984 ASSERT(!txg_list_member(&vd->vdev_ms_list, msp, t));
1985
1986 mutex_exit(&msp->ms_lock);
1987 cv_destroy(&msp->ms_load_cv);
1988 mutex_destroy(&msp->ms_lock);
1989 mutex_destroy(&msp->ms_sync_lock);
1990 ASSERT3U(msp->ms_allocator, ==, -1);
1991
1992 kmem_free(msp, sizeof (metaslab_t));
1993 }
1994
1995 #define FRAGMENTATION_TABLE_SIZE 17
1996
1997 /*
1998 * This table defines a segment size based fragmentation metric that will
1999 * allow each metaslab to derive its own fragmentation value. This is done
2000 * by calculating the space in each bucket of the spacemap histogram and
2001 * multiplying that by the fragmentation metric in this table. Doing
2002 * this for all buckets and dividing it by the total amount of free
2003 * space in this metaslab (i.e. the total free space in all buckets) gives
2004 * us the fragmentation metric. This means that a high fragmentation metric
2005 * equates to most of the free space being comprised of small segments.
2006 * Conversely, if the metric is low, then most of the free space is in
2007 * large segments. A 10% change in fragmentation equates to approximately
2008 * double the number of segments.
2009 *
2010 * This table defines 0% fragmented space using 16MB segments. Testing has
2011 * shown that segments that are greater than or equal to 16MB do not suffer
2012 * from drastic performance problems. Using this value, we derive the rest
2013 * of the table. Since the fragmentation value is never stored on disk, it
2014 * is possible to change these calculations in the future.
2015 */
2016 int zfs_frag_table[FRAGMENTATION_TABLE_SIZE] = {
2017 100, /* 512B */
2018 100, /* 1K */
2019 98, /* 2K */
2020 95, /* 4K */
2021 90, /* 8K */
2022 80, /* 16K */
2023 70, /* 32K */
2024 60, /* 64K */
2025 50, /* 128K */
2026 40, /* 256K */
2027 30, /* 512K */
2028 20, /* 1M */
2029 15, /* 2M */
2030 10, /* 4M */
2031 5, /* 8M */
2032 0 /* 16M */
2033 };
2034
2035 /*
2036 * Calculate the metaslab's fragmentation metric and set ms_fragmentation.
2037 * Setting this value to ZFS_FRAG_INVALID means that the metaslab has not
2038 * been upgraded and does not support this metric. Otherwise, the return
2039 * value should be in the range [0, 100].
2040 */
2041 static void
2042 metaslab_set_fragmentation(metaslab_t *msp)
2043 {
2044 spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
2045 uint64_t fragmentation = 0;
2046 uint64_t total = 0;
2047 boolean_t feature_enabled = spa_feature_is_enabled(spa,
2048 SPA_FEATURE_SPACEMAP_HISTOGRAM);
2049
2050 if (!feature_enabled) {
2051 msp->ms_fragmentation = ZFS_FRAG_INVALID;
2052 return;
2053 }
2054
2055 /*
2056 * A null space map means that the entire metaslab is free
2057 * and thus is not fragmented.
2058 */
2059 if (msp->ms_sm == NULL) {
2060 msp->ms_fragmentation = 0;
2061 return;
2062 }
2063
2064 /*
2065 * If this metaslab's space map has not been upgraded, flag it
2066 * so that we upgrade next time we encounter it.
2067 */
2068 if (msp->ms_sm->sm_dbuf->db_size != sizeof (space_map_phys_t)) {
2069 uint64_t txg = spa_syncing_txg(spa);
2070 vdev_t *vd = msp->ms_group->mg_vd;
2071
2072 /*
2073 * If we've reached the final dirty txg, then we must
2074 * be shutting down the pool. We don't want to dirty
2075 * any data past this point so skip setting the condense
2076 * flag. We can retry this action the next time the pool
2077 * is imported.
2078 */
2079 if (spa_writeable(spa) && txg < spa_final_dirty_txg(spa)) {
2080 msp->ms_condense_wanted = B_TRUE;
2081 vdev_dirty(vd, VDD_METASLAB, msp, txg + 1);
2082 zfs_dbgmsg("txg %llu, requesting force condense: "
2083 "ms_id %llu, vdev_id %llu", txg, msp->ms_id,
2084 vd->vdev_id);
2085 }
2086 msp->ms_fragmentation = ZFS_FRAG_INVALID;
2087 return;
2088 }
2089
2090 for (int i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++) {
2091 uint64_t space = 0;
2092 uint8_t shift = msp->ms_sm->sm_shift;
2093
2094 int idx = MIN(shift - SPA_MINBLOCKSHIFT + i,
2095 FRAGMENTATION_TABLE_SIZE - 1);
2096
2097 if (msp->ms_sm->sm_phys->smp_histogram[i] == 0)
2098 continue;
2099
2100 space = msp->ms_sm->sm_phys->smp_histogram[i] << (i + shift);
2101 total += space;
2102
2103 ASSERT3U(idx, <, FRAGMENTATION_TABLE_SIZE);
2104 fragmentation += space * zfs_frag_table[idx];
2105 }
2106
2107 if (total > 0)
2108 fragmentation /= total;
2109 ASSERT3U(fragmentation, <=, 100);
2110
2111 msp->ms_fragmentation = fragmentation;
2112 }
2113
2114 /*
2115 * Compute a weight -- a selection preference value -- for the given metaslab.
2116 * This is based on the amount of free space, the level of fragmentation,
2117 * the LBA range, and whether the metaslab is loaded.
2118 */
2119 static uint64_t
2120 metaslab_space_weight(metaslab_t *msp)
2121 {
2122 metaslab_group_t *mg = msp->ms_group;
2123 vdev_t *vd = mg->mg_vd;
2124 uint64_t weight, space;
2125
2126 ASSERT(MUTEX_HELD(&msp->ms_lock));
2127 ASSERT(!vd->vdev_removing);
2128
2129 /*
2130 * The baseline weight is the metaslab's free space.
2131 */
2132 space = msp->ms_size - metaslab_allocated_space(msp);
2133
2134 if (metaslab_fragmentation_factor_enabled &&
2135 msp->ms_fragmentation != ZFS_FRAG_INVALID) {
2136 /*
2137 * Use the fragmentation information to inversely scale
2138 * down the baseline weight. We need to ensure that we
2139 * don't exclude this metaslab completely when it's 100%
2140 * fragmented. To avoid this we reduce the fragmented value
2141 * by 1.
2142 */
2143 space = (space * (100 - (msp->ms_fragmentation - 1))) / 100;
2144
2145 /*
2146 * If space < SPA_MINBLOCKSIZE, then we will not allocate from
2147 * this metaslab again. The fragmentation metric may have
2148 * decreased the space to something smaller than
2149 * SPA_MINBLOCKSIZE, so reset the space to SPA_MINBLOCKSIZE
2150 * so that we can consume any remaining space.
2151 */
2152 if (space > 0 && space < SPA_MINBLOCKSIZE)
2153 space = SPA_MINBLOCKSIZE;
2154 }
2155 weight = space;
2156
2157 /*
2158 * Modern disks have uniform bit density and constant angular velocity.
2159 * Therefore, the outer recording zones are faster (higher bandwidth)
2160 * than the inner zones by the ratio of outer to inner track diameter,
2161 * which is typically around 2:1. We account for this by assigning
2162 * higher weight to lower metaslabs (multiplier ranging from 2x to 1x).
2163 * In effect, this means that we'll select the metaslab with the most
2164 * free bandwidth rather than simply the one with the most free space.
2165 */
2166 if (metaslab_lba_weighting_enabled) {
2167 weight = 2 * weight - (msp->ms_id * weight) / vd->vdev_ms_count;
2168 ASSERT(weight >= space && weight <= 2 * space);
2169 }
2170
2171 /*
2172 * If this metaslab is one we're actively using, adjust its
2173 * weight to make it preferable to any inactive metaslab so
2174 * we'll polish it off. If the fragmentation on this metaslab
2175 * has exceed our threshold, then don't mark it active.
2176 */
2177 if (msp->ms_loaded && msp->ms_fragmentation != ZFS_FRAG_INVALID &&
2178 msp->ms_fragmentation <= zfs_metaslab_fragmentation_threshold) {
2179 weight |= (msp->ms_weight & METASLAB_ACTIVE_MASK);
2180 }
2181
2182 WEIGHT_SET_SPACEBASED(weight);
2183 return (weight);
2184 }
2185
2186 /*
2187 * Return the weight of the specified metaslab, according to the segment-based
2188 * weighting algorithm. The metaslab must be loaded. This function can
2189 * be called within a sync pass since it relies only on the metaslab's
2190 * range tree which is always accurate when the metaslab is loaded.
2191 */
2192 static uint64_t
2193 metaslab_weight_from_range_tree(metaslab_t *msp)
2194 {
2195 uint64_t weight = 0;
2196 uint32_t segments = 0;
2197
2198 ASSERT(msp->ms_loaded);
2199
2200 for (int i = RANGE_TREE_HISTOGRAM_SIZE - 1; i >= SPA_MINBLOCKSHIFT;
2201 i--) {
2202 uint8_t shift = msp->ms_group->mg_vd->vdev_ashift;
2203 int max_idx = SPACE_MAP_HISTOGRAM_SIZE + shift - 1;
2204
2205 segments <<= 1;
2206 segments += msp->ms_allocatable->rt_histogram[i];
2207
2208 /*
2209 * The range tree provides more precision than the space map
2210 * and must be downgraded so that all values fit within the
2211 * space map's histogram. This allows us to compare loaded
2212 * vs. unloaded metaslabs to determine which metaslab is
2213 * considered "best".
2214 */
2215 if (i > max_idx)
2216 continue;
2217
2218 if (segments != 0) {
2219 WEIGHT_SET_COUNT(weight, segments);
2220 WEIGHT_SET_INDEX(weight, i);
2221 WEIGHT_SET_ACTIVE(weight, 0);
2222 break;
2223 }
2224 }
2225 return (weight);
2226 }
2227
2228 /*
2229 * Calculate the weight based on the on-disk histogram. This should only
2230 * be called after a sync pass has completely finished since the on-disk
2231 * information is updated in metaslab_sync().
2232 */
2233 static uint64_t
2234 metaslab_weight_from_spacemap(metaslab_t *msp)
2235 {
2236 space_map_t *sm = msp->ms_sm;
2237 ASSERT(!msp->ms_loaded);
2238 ASSERT(sm != NULL);
2239 ASSERT3U(space_map_object(sm), !=, 0);
2240 ASSERT3U(sm->sm_dbuf->db_size, ==, sizeof (space_map_phys_t));
2241
2242 /*
2243 * Create a joint histogram from all the segments that have made
2244 * it to the metaslab's space map histogram, that are not yet
2245 * available for allocation because they are still in the freeing
2246 * pipeline (e.g. freeing, freed, and defer trees). Then subtract
2247 * these segments from the space map's histogram to get a more
2248 * accurate weight.
2249 */
2250 uint64_t deferspace_histogram[SPACE_MAP_HISTOGRAM_SIZE] = {0};
2251 for (int i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++)
2252 deferspace_histogram[i] += msp->ms_synchist[i];
2253 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
2254 for (int i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++) {
2255 deferspace_histogram[i] += msp->ms_deferhist[t][i];
2256 }
2257 }
2258
2259 uint64_t weight = 0;
2260 for (int i = SPACE_MAP_HISTOGRAM_SIZE - 1; i >= 0; i--) {
2261 ASSERT3U(sm->sm_phys->smp_histogram[i], >=,
2262 deferspace_histogram[i]);
2263 uint64_t count =
2264 sm->sm_phys->smp_histogram[i] - deferspace_histogram[i];
2265 if (count != 0) {
2266 WEIGHT_SET_COUNT(weight, count);
2267 WEIGHT_SET_INDEX(weight, i + sm->sm_shift);
2268 WEIGHT_SET_ACTIVE(weight, 0);
2269 break;
2270 }
2271 }
2272 return (weight);
2273 }
2274
2275 /*
2276 * Compute a segment-based weight for the specified metaslab. The weight
2277 * is determined by highest bucket in the histogram. The information
2278 * for the highest bucket is encoded into the weight value.
2279 */
2280 static uint64_t
2281 metaslab_segment_weight(metaslab_t *msp)
2282 {
2283 metaslab_group_t *mg = msp->ms_group;
2284 uint64_t weight = 0;
2285 uint8_t shift = mg->mg_vd->vdev_ashift;
2286
2287 ASSERT(MUTEX_HELD(&msp->ms_lock));
2288
2289 /*
2290 * The metaslab is completely free.
2291 */
2292 if (metaslab_allocated_space(msp) == 0) {
2293 int idx = highbit64(msp->ms_size) - 1;
2294 int max_idx = SPACE_MAP_HISTOGRAM_SIZE + shift - 1;
2295
2296 if (idx < max_idx) {
2297 WEIGHT_SET_COUNT(weight, 1ULL);
2298 WEIGHT_SET_INDEX(weight, idx);
2299 } else {
2300 WEIGHT_SET_COUNT(weight, 1ULL << (idx - max_idx));
2301 WEIGHT_SET_INDEX(weight, max_idx);
2302 }
2303 WEIGHT_SET_ACTIVE(weight, 0);
2304 ASSERT(!WEIGHT_IS_SPACEBASED(weight));
2305
2306 return (weight);
2307 }
2308
2309 ASSERT3U(msp->ms_sm->sm_dbuf->db_size, ==, sizeof (space_map_phys_t));
2310
2311 /*
2312 * If the metaslab is fully allocated then just make the weight 0.
2313 */
2314 if (metaslab_allocated_space(msp) == msp->ms_size)
2315 return (0);
2316 /*
2317 * If the metaslab is already loaded, then use the range tree to
2318 * determine the weight. Otherwise, we rely on the space map information
2319 * to generate the weight.
2320 */
2321 if (msp->ms_loaded) {
2322 weight = metaslab_weight_from_range_tree(msp);
2323 } else {
2324 weight = metaslab_weight_from_spacemap(msp);
2325 }
2326
2327 /*
2328 * If the metaslab was active the last time we calculated its weight
2329 * then keep it active. We want to consume the entire region that
2330 * is associated with this weight.
2331 */
2332 if (msp->ms_activation_weight != 0 && weight != 0)
2333 WEIGHT_SET_ACTIVE(weight, WEIGHT_GET_ACTIVE(msp->ms_weight));
2334 return (weight);
2335 }
2336
2337 /*
2338 * Determine if we should attempt to allocate from this metaslab. If the
2339 * metaslab has a maximum size then we can quickly determine if the desired
2340 * allocation size can be satisfied. Otherwise, if we're using segment-based
2341 * weighting then we can determine the maximum allocation that this metaslab
2342 * can accommodate based on the index encoded in the weight. If we're using
2343 * space-based weights then rely on the entire weight (excluding the weight
2344 * type bit).
2345 */
2346 boolean_t
2347 metaslab_should_allocate(metaslab_t *msp, uint64_t asize)
2348 {
2349 boolean_t should_allocate;
2350
2351 if (msp->ms_max_size != 0)
2352 return (msp->ms_max_size >= asize);
2353
2354 if (!WEIGHT_IS_SPACEBASED(msp->ms_weight)) {
2355 /*
2356 * The metaslab segment weight indicates segments in the
2357 * range [2^i, 2^(i+1)), where i is the index in the weight.
2358 * Since the asize might be in the middle of the range, we
2359 * should attempt the allocation if asize < 2^(i+1).
2360 */
2361 should_allocate = (asize <
2362 1ULL << (WEIGHT_GET_INDEX(msp->ms_weight) + 1));
2363 } else {
2364 should_allocate = (asize <=
2365 (msp->ms_weight & ~METASLAB_WEIGHT_TYPE));
2366 }
2367 return (should_allocate);
2368 }
2369
2370 static uint64_t
2371 metaslab_weight(metaslab_t *msp)
2372 {
2373 vdev_t *vd = msp->ms_group->mg_vd;
2374 spa_t *spa = vd->vdev_spa;
2375 uint64_t weight;
2376
2377 ASSERT(MUTEX_HELD(&msp->ms_lock));
2378
2379 /*
2380 * If this vdev is in the process of being removed, there is nothing
2381 * for us to do here.
2382 */
2383 if (vd->vdev_removing)
2384 return (0);
2385
2386 metaslab_set_fragmentation(msp);
2387
2388 /*
2389 * Update the maximum size if the metaslab is loaded. This will
2390 * ensure that we get an accurate maximum size if newly freed space
2391 * has been added back into the free tree.
2392 */
2393 if (msp->ms_loaded)
2394 msp->ms_max_size = metaslab_block_maxsize(msp);
2395 else
2396 ASSERT0(msp->ms_max_size);
2397
2398 /*
2399 * Segment-based weighting requires space map histogram support.
2400 */
2401 if (zfs_metaslab_segment_weight_enabled &&
2402 spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM) &&
2403 (msp->ms_sm == NULL || msp->ms_sm->sm_dbuf->db_size ==
2404 sizeof (space_map_phys_t))) {
2405 weight = metaslab_segment_weight(msp);
2406 } else {
2407 weight = metaslab_space_weight(msp);
2408 }
2409 return (weight);
2410 }
2411
2412 void
2413 metaslab_recalculate_weight_and_sort(metaslab_t *msp)
2414 {
2415 /* note: we preserve the mask (e.g. indication of primary, etc..) */
2416 uint64_t was_active = msp->ms_weight & METASLAB_ACTIVE_MASK;
2417 metaslab_group_sort(msp->ms_group, msp,
2418 metaslab_weight(msp) | was_active);
2419 }
2420
2421 static int
2422 metaslab_activate_allocator(metaslab_group_t *mg, metaslab_t *msp,
2423 int allocator, uint64_t activation_weight)
2424 {
2425 /*
2426 * If we're activating for the claim code, we don't want to actually
2427 * set the metaslab up for a specific allocator.
2428 */
2429 if (activation_weight == METASLAB_WEIGHT_CLAIM)
2430 return (0);
2431 metaslab_t **arr = (activation_weight == METASLAB_WEIGHT_PRIMARY ?
2432 mg->mg_primaries : mg->mg_secondaries);
2433
2434 ASSERT(MUTEX_HELD(&msp->ms_lock));
2435 mutex_enter(&mg->mg_lock);
2436 if (arr[allocator] != NULL) {
2437 mutex_exit(&mg->mg_lock);
2438 return (EEXIST);
2439 }
2440
2441 arr[allocator] = msp;
2442 ASSERT3S(msp->ms_allocator, ==, -1);
2443 msp->ms_allocator = allocator;
2444 msp->ms_primary = (activation_weight == METASLAB_WEIGHT_PRIMARY);
2445 mutex_exit(&mg->mg_lock);
2446
2447 return (0);
2448 }
2449
2450 static int
2451 metaslab_activate(metaslab_t *msp, int allocator, uint64_t activation_weight)
2452 {
2453 ASSERT(MUTEX_HELD(&msp->ms_lock));
2454
2455 if ((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
2456 int error = metaslab_load(msp);
2457 if (error != 0) {
2458 metaslab_group_sort(msp->ms_group, msp, 0);
2459 return (error);
2460 }
2461 if ((msp->ms_weight & METASLAB_ACTIVE_MASK) != 0) {
2462 /*
2463 * The metaslab was activated for another allocator
2464 * while we were waiting, we should reselect.
2465 */
2466 return (EBUSY);
2467 }
2468 if ((error = metaslab_activate_allocator(msp->ms_group, msp,
2469 allocator, activation_weight)) != 0) {
2470 return (error);
2471 }
2472
2473 msp->ms_activation_weight = msp->ms_weight;
2474 metaslab_group_sort(msp->ms_group, msp,
2475 msp->ms_weight | activation_weight);
2476 }
2477 ASSERT(msp->ms_loaded);
2478 ASSERT(msp->ms_weight & METASLAB_ACTIVE_MASK);
2479
2480 return (0);
2481 }
2482
2483 static void
2484 metaslab_passivate_allocator(metaslab_group_t *mg, metaslab_t *msp,
2485 uint64_t weight)
2486 {
2487 ASSERT(MUTEX_HELD(&msp->ms_lock));
2488 if (msp->ms_weight & METASLAB_WEIGHT_CLAIM) {
2489 metaslab_group_sort(mg, msp, weight);
2490 return;
2491 }
2492
2493 mutex_enter(&mg->mg_lock);
2494 ASSERT3P(msp->ms_group, ==, mg);
2495 if (msp->ms_primary) {
2496 ASSERT3U(0, <=, msp->ms_allocator);
2497 ASSERT3U(msp->ms_allocator, <, mg->mg_allocators);
2498 ASSERT3P(mg->mg_primaries[msp->ms_allocator], ==, msp);
2499 ASSERT(msp->ms_weight & METASLAB_WEIGHT_PRIMARY);
2500 mg->mg_primaries[msp->ms_allocator] = NULL;
2501 } else {
2502 ASSERT(msp->ms_weight & METASLAB_WEIGHT_SECONDARY);
2503 ASSERT3P(mg->mg_secondaries[msp->ms_allocator], ==, msp);
2504 mg->mg_secondaries[msp->ms_allocator] = NULL;
2505 }
2506 msp->ms_allocator = -1;
2507 metaslab_group_sort_impl(mg, msp, weight);
2508 mutex_exit(&mg->mg_lock);
2509 }
2510
2511 static void
2512 metaslab_passivate(metaslab_t *msp, uint64_t weight)
2513 {
2514 uint64_t size = weight & ~METASLAB_WEIGHT_TYPE;
2515
2516 /*
2517 * If size < SPA_MINBLOCKSIZE, then we will not allocate from
2518 * this metaslab again. In that case, it had better be empty,
2519 * or we would be leaving space on the table.
2520 */
2521 ASSERT(size >= SPA_MINBLOCKSIZE ||
2522 range_tree_is_empty(msp->ms_allocatable));
2523 ASSERT0(weight & METASLAB_ACTIVE_MASK);
2524
2525 msp->ms_activation_weight = 0;
2526 metaslab_passivate_allocator(msp->ms_group, msp, weight);
2527 ASSERT((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0);
2528 }
2529
2530 /*
2531 * Segment-based metaslabs are activated once and remain active until
2532 * we either fail an allocation attempt (similar to space-based metaslabs)
2533 * or have exhausted the free space in zfs_metaslab_switch_threshold
2534 * buckets since the metaslab was activated. This function checks to see
2535 * if we've exhaused the zfs_metaslab_switch_threshold buckets in the
2536 * metaslab and passivates it proactively. This will allow us to select a
2537 * metaslabs with larger contiguous region if any remaining within this
2538 * metaslab group. If we're in sync pass > 1, then we continue using this
2539 * metaslab so that we don't dirty more block and cause more sync passes.
2540 */
2541 void
2542 metaslab_segment_may_passivate(metaslab_t *msp)
2543 {
2544 spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
2545
2546 if (WEIGHT_IS_SPACEBASED(msp->ms_weight) || spa_sync_pass(spa) > 1)
2547 return;
2548
2549 /*
2550 * Since we are in the middle of a sync pass, the most accurate
2551 * information that is accessible to us is the in-core range tree
2552 * histogram; calculate the new weight based on that information.
2553 */
2554 uint64_t weight = metaslab_weight_from_range_tree(msp);
2555 int activation_idx = WEIGHT_GET_INDEX(msp->ms_activation_weight);
2556 int current_idx = WEIGHT_GET_INDEX(weight);
2557
2558 if (current_idx <= activation_idx - zfs_metaslab_switch_threshold)
2559 metaslab_passivate(msp, weight);
2560 }
2561
2562 static void
2563 metaslab_preload(void *arg)
2564 {
2565 metaslab_t *msp = arg;
2566 spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
2567
2568 ASSERT(!MUTEX_HELD(&msp->ms_group->mg_lock));
2569
2570 mutex_enter(&msp->ms_lock);
2571 (void) metaslab_load(msp);
2572 msp->ms_selected_txg = spa_syncing_txg(spa);
2573 mutex_exit(&msp->ms_lock);
2574 }
2575
2576 static void
2577 metaslab_group_preload(metaslab_group_t *mg)
2578 {
2579 spa_t *spa = mg->mg_vd->vdev_spa;
2580 metaslab_t *msp;
2581 avl_tree_t *t = &mg->mg_metaslab_tree;
2582 int m = 0;
2583
2584 if (spa_shutting_down(spa) || !metaslab_preload_enabled) {
2585 taskq_wait(mg->mg_taskq);
2586 return;
2587 }
2588
2589 mutex_enter(&mg->mg_lock);
2590
2591 /*
2592 * Load the next potential metaslabs
2593 */
2594 for (msp = avl_first(t); msp != NULL; msp = AVL_NEXT(t, msp)) {
2595 ASSERT3P(msp->ms_group, ==, mg);
2596
2597 /*
2598 * We preload only the maximum number of metaslabs specified
2599 * by metaslab_preload_limit. If a metaslab is being forced
2600 * to condense then we preload it too. This will ensure
2601 * that force condensing happens in the next txg.
2602 */
2603 if (++m > metaslab_preload_limit && !msp->ms_condense_wanted) {
2604 continue;
2605 }
2606
2607 VERIFY(taskq_dispatch(mg->mg_taskq, metaslab_preload,
2608 msp, TQ_SLEEP) != TASKQID_INVALID);
2609 }
2610 mutex_exit(&mg->mg_lock);
2611 }
2612
2613 /*
2614 * Determine if the space map's on-disk footprint is past our tolerance
2615 * for inefficiency. We would like to use the following criteria to make
2616 * our decision:
2617 *
2618 * 1. The size of the space map object should not dramatically increase as a
2619 * result of writing out the free space range tree.
2620 *
2621 * 2. The minimal on-disk space map representation is zfs_condense_pct/100
2622 * times the size than the free space range tree representation
2623 * (i.e. zfs_condense_pct = 110 and in-core = 1MB, minimal = 1.1MB).
2624 *
2625 * 3. The on-disk size of the space map should actually decrease.
2626 *
2627 * Unfortunately, we cannot compute the on-disk size of the space map in this
2628 * context because we cannot accurately compute the effects of compression, etc.
2629 * Instead, we apply the heuristic described in the block comment for
2630 * zfs_metaslab_condense_block_threshold - we only condense if the space used
2631 * is greater than a threshold number of blocks.
2632 */
2633 static boolean_t
2634 metaslab_should_condense(metaslab_t *msp)
2635 {
2636 space_map_t *sm = msp->ms_sm;
2637 vdev_t *vd = msp->ms_group->mg_vd;
2638 uint64_t vdev_blocksize = 1 << vd->vdev_ashift;
2639 uint64_t current_txg = spa_syncing_txg(vd->vdev_spa);
2640
2641 ASSERT(MUTEX_HELD(&msp->ms_lock));
2642 ASSERT(msp->ms_loaded);
2643
2644 /*
2645 * Allocations and frees in early passes are generally more space
2646 * efficient (in terms of blocks described in space map entries)
2647 * than the ones in later passes (e.g. we don't compress after
2648 * sync pass 5) and condensing a metaslab multiple times in a txg
2649 * could degrade performance.
2650 *
2651 * Thus we prefer condensing each metaslab at most once every txg at
2652 * the earliest sync pass possible. If a metaslab is eligible for
2653 * condensing again after being considered for condensing within the
2654 * same txg, it will hopefully be dirty in the next txg where it will
2655 * be condensed at an earlier pass.
2656 */
2657 if (msp->ms_condense_checked_txg == current_txg)
2658 return (B_FALSE);
2659 msp->ms_condense_checked_txg = current_txg;
2660
2661 /*
2662 * We always condense metaslabs that are empty and metaslabs for
2663 * which a condense request has been made.
2664 */
2665 if (avl_is_empty(&msp->ms_allocatable_by_size) ||
2666 msp->ms_condense_wanted)
2667 return (B_TRUE);
2668
2669 uint64_t object_size = space_map_length(msp->ms_sm);
2670 uint64_t optimal_size = space_map_estimate_optimal_size(sm,
2671 msp->ms_allocatable, SM_NO_VDEVID);
2672
2673 dmu_object_info_t doi;
2674 dmu_object_info_from_db(sm->sm_dbuf, &doi);
2675 uint64_t record_size = MAX(doi.doi_data_block_size, vdev_blocksize);
2676
2677 return (object_size >= (optimal_size * zfs_condense_pct / 100) &&
2678 object_size > zfs_metaslab_condense_block_threshold * record_size);
2679 }
2680
2681 /*
2682 * Condense the on-disk space map representation to its minimized form.
2683 * The minimized form consists of a small number of allocations followed by
2684 * the entries of the free range tree.
2685 */
2686 static void
2687 metaslab_condense(metaslab_t *msp, uint64_t txg, dmu_tx_t *tx)
2688 {
2689 range_tree_t *condense_tree;
2690 space_map_t *sm = msp->ms_sm;
2691
2692 ASSERT(MUTEX_HELD(&msp->ms_lock));
2693 ASSERT(msp->ms_loaded);
2694
2695 zfs_dbgmsg("condensing: txg %llu, msp[%llu] %p, vdev id %llu, "
2696 "spa %s, smp size %llu, segments %lu, forcing condense=%s", txg,
2697 msp->ms_id, msp, msp->ms_group->mg_vd->vdev_id,
2698 msp->ms_group->mg_vd->vdev_spa->spa_name,
2699 space_map_length(msp->ms_sm),
2700 avl_numnodes(&msp->ms_allocatable->rt_root),
2701 msp->ms_condense_wanted ? "TRUE" : "FALSE");
2702
2703 msp->ms_condense_wanted = B_FALSE;
2704
2705 /*
2706 * Create an range tree that is 100% allocated. We remove segments
2707 * that have been freed in this txg, any deferred frees that exist,
2708 * and any allocation in the future. Removing segments should be
2709 * a relatively inexpensive operation since we expect these trees to
2710 * have a small number of nodes.
2711 */
2712 condense_tree = range_tree_create(NULL, NULL);
2713 range_tree_add(condense_tree, msp->ms_start, msp->ms_size);
2714
2715 range_tree_walk(msp->ms_freeing, range_tree_remove, condense_tree);
2716 range_tree_walk(msp->ms_freed, range_tree_remove, condense_tree);
2717
2718 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
2719 range_tree_walk(msp->ms_defer[t],
2720 range_tree_remove, condense_tree);
2721 }
2722
2723 for (int t = 1; t < TXG_CONCURRENT_STATES; t++) {
2724 range_tree_walk(msp->ms_allocating[(txg + t) & TXG_MASK],
2725 range_tree_remove, condense_tree);
2726 }
2727
2728 /*
2729 * We're about to drop the metaslab's lock thus allowing
2730 * other consumers to change it's content. Set the
2731 * metaslab's ms_condensing flag to ensure that
2732 * allocations on this metaslab do not occur while we're
2733 * in the middle of committing it to disk. This is only critical
2734 * for ms_allocatable as all other range trees use per txg
2735 * views of their content.
2736 */
2737 msp->ms_condensing = B_TRUE;
2738
2739 mutex_exit(&msp->ms_lock);
2740 space_map_truncate(sm, zfs_metaslab_sm_blksz, tx);
2741
2742 /*
2743 * While we would ideally like to create a space map representation
2744 * that consists only of allocation records, doing so can be
2745 * prohibitively expensive because the in-core free tree can be
2746 * large, and therefore computationally expensive to subtract
2747 * from the condense_tree. Instead we sync out two trees, a cheap
2748 * allocation only tree followed by the in-core free tree. While not
2749 * optimal, this is typically close to optimal, and much cheaper to
2750 * compute.
2751 */
2752 space_map_write(sm, condense_tree, SM_ALLOC, SM_NO_VDEVID, tx);
2753 range_tree_vacate(condense_tree, NULL, NULL);
2754 range_tree_destroy(condense_tree);
2755
2756 space_map_write(sm, msp->ms_allocatable, SM_FREE, SM_NO_VDEVID, tx);
2757 mutex_enter(&msp->ms_lock);
2758 msp->ms_condensing = B_FALSE;
2759 }
2760
2761 /*
2762 * Write a metaslab to disk in the context of the specified transaction group.
2763 */
2764 void
2765 metaslab_sync(metaslab_t *msp, uint64_t txg)
2766 {
2767 metaslab_group_t *mg = msp->ms_group;
2768 vdev_t *vd = mg->mg_vd;
2769 spa_t *spa = vd->vdev_spa;
2770 objset_t *mos = spa_meta_objset(spa);
2771 range_tree_t *alloctree = msp->ms_allocating[txg & TXG_MASK];
2772 dmu_tx_t *tx;
2773 uint64_t object = space_map_object(msp->ms_sm);
2774
2775 ASSERT(!vd->vdev_ishole);
2776
2777 /*
2778 * This metaslab has just been added so there's no work to do now.
2779 */
2780 if (msp->ms_freeing == NULL) {
2781 ASSERT3P(alloctree, ==, NULL);
2782 return;
2783 }
2784
2785 ASSERT3P(alloctree, !=, NULL);
2786 ASSERT3P(msp->ms_freeing, !=, NULL);
2787 ASSERT3P(msp->ms_freed, !=, NULL);
2788 ASSERT3P(msp->ms_checkpointing, !=, NULL);
2789
2790 /*
2791 * Normally, we don't want to process a metaslab if there are no
2792 * allocations or frees to perform. However, if the metaslab is being
2793 * forced to condense and it's loaded, we need to let it through.
2794 */
2795 if (range_tree_is_empty(alloctree) &&
2796 range_tree_is_empty(msp->ms_freeing) &&
2797 range_tree_is_empty(msp->ms_checkpointing) &&
2798 !(msp->ms_loaded && msp->ms_condense_wanted))
2799 return;
2800
2801
2802 VERIFY(txg <= spa_final_dirty_txg(spa));
2803
2804 /*
2805 * The only state that can actually be changing concurrently
2806 * with metaslab_sync() is the metaslab's ms_allocatable. No
2807 * other thread can be modifying this txg's alloc, freeing,
2808 * freed, or space_map_phys_t. We drop ms_lock whenever we
2809 * could call into the DMU, because the DMU can call down to
2810 * us (e.g. via zio_free()) at any time.
2811 *
2812 * The spa_vdev_remove_thread() can be reading metaslab state
2813 * concurrently, and it is locked out by the ms_sync_lock.
2814 * Note that the ms_lock is insufficient for this, because it
2815 * is dropped by space_map_write().
2816 */
2817 tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
2818
2819 if (msp->ms_sm == NULL) {
2820 uint64_t new_object;
2821
2822 new_object = space_map_alloc(mos, zfs_metaslab_sm_blksz, tx);
2823 VERIFY3U(new_object, !=, 0);
2824
2825 VERIFY0(space_map_open(&msp->ms_sm, mos, new_object,
2826 msp->ms_start, msp->ms_size, vd->vdev_ashift));
2827
2828 ASSERT(msp->ms_sm != NULL);
2829 ASSERT0(metaslab_allocated_space(msp));
2830 }
2831
2832 if (!range_tree_is_empty(msp->ms_checkpointing) &&
2833 vd->vdev_checkpoint_sm == NULL) {
2834 ASSERT(spa_has_checkpoint(spa));
2835
2836 uint64_t new_object = space_map_alloc(mos,
2837 vdev_standard_sm_blksz, tx);
2838 VERIFY3U(new_object, !=, 0);
2839
2840 VERIFY0(space_map_open(&vd->vdev_checkpoint_sm,
2841 mos, new_object, 0, vd->vdev_asize, vd->vdev_ashift));
2842 ASSERT3P(vd->vdev_checkpoint_sm, !=, NULL);
2843
2844 /*
2845 * We save the space map object as an entry in vdev_top_zap
2846 * so it can be retrieved when the pool is reopened after an
2847 * export or through zdb.
2848 */
2849 VERIFY0(zap_add(vd->vdev_spa->spa_meta_objset,
2850 vd->vdev_top_zap, VDEV_TOP_ZAP_POOL_CHECKPOINT_SM,
2851 sizeof (new_object), 1, &new_object, tx));
2852 }
2853
2854 mutex_enter(&msp->ms_sync_lock);
2855 mutex_enter(&msp->ms_lock);
2856
2857 /*
2858 * Note: metaslab_condense() clears the space map's histogram.
2859 * Therefore we must verify and remove this histogram before
2860 * condensing.
2861 */
2862 metaslab_group_histogram_verify(mg);
2863 metaslab_class_histogram_verify(mg->mg_class);
2864 metaslab_group_histogram_remove(mg, msp);
2865
2866 if (msp->ms_loaded && metaslab_should_condense(msp)) {
2867 metaslab_condense(msp, txg, tx);
2868 } else {
2869 mutex_exit(&msp->ms_lock);
2870 space_map_write(msp->ms_sm, alloctree, SM_ALLOC,
2871 SM_NO_VDEVID, tx);
2872 space_map_write(msp->ms_sm, msp->ms_freeing, SM_FREE,
2873 SM_NO_VDEVID, tx);
2874 mutex_enter(&msp->ms_lock);
2875 }
2876
2877 msp->ms_allocated_space += range_tree_space(alloctree);
2878 ASSERT3U(msp->ms_allocated_space, >=,
2879 range_tree_space(msp->ms_freeing));
2880 msp->ms_allocated_space -= range_tree_space(msp->ms_freeing);
2881
2882 if (!range_tree_is_empty(msp->ms_checkpointing)) {
2883 ASSERT(spa_has_checkpoint(spa));
2884 ASSERT3P(vd->vdev_checkpoint_sm, !=, NULL);
2885
2886 /*
2887 * Since we are doing writes to disk and the ms_checkpointing
2888 * tree won't be changing during that time, we drop the
2889 * ms_lock while writing to the checkpoint space map.
2890 */
2891 mutex_exit(&msp->ms_lock);
2892 space_map_write(vd->vdev_checkpoint_sm,
2893 msp->ms_checkpointing, SM_FREE, SM_NO_VDEVID, tx);
2894 mutex_enter(&msp->ms_lock);
2895
2896 spa->spa_checkpoint_info.sci_dspace +=
2897 range_tree_space(msp->ms_checkpointing);
2898 vd->vdev_stat.vs_checkpoint_space +=
2899 range_tree_space(msp->ms_checkpointing);
2900 ASSERT3U(vd->vdev_stat.vs_checkpoint_space, ==,
2901 -space_map_allocated(vd->vdev_checkpoint_sm));
2902
2903 range_tree_vacate(msp->ms_checkpointing, NULL, NULL);
2904 }
2905
2906 if (msp->ms_loaded) {
2907 /*
2908 * When the space map is loaded, we have an accurate
2909 * histogram in the range tree. This gives us an opportunity
2910 * to bring the space map's histogram up-to-date so we clear
2911 * it first before updating it.
2912 */
2913 space_map_histogram_clear(msp->ms_sm);
2914 space_map_histogram_add(msp->ms_sm, msp->ms_allocatable, tx);
2915
2916 /*
2917 * Since we've cleared the histogram we need to add back
2918 * any free space that has already been processed, plus
2919 * any deferred space. This allows the on-disk histogram
2920 * to accurately reflect all free space even if some space
2921 * is not yet available for allocation (i.e. deferred).
2922 */
2923 space_map_histogram_add(msp->ms_sm, msp->ms_freed, tx);
2924
2925 /*
2926 * Add back any deferred free space that has not been
2927 * added back into the in-core free tree yet. This will
2928 * ensure that we don't end up with a space map histogram
2929 * that is completely empty unless the metaslab is fully
2930 * allocated.
2931 */
2932 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
2933 space_map_histogram_add(msp->ms_sm,
2934 msp->ms_defer[t], tx);
2935 }
2936 }
2937
2938 /*
2939 * Always add the free space from this sync pass to the space
2940 * map histogram. We want to make sure that the on-disk histogram
2941 * accounts for all free space. If the space map is not loaded,
2942 * then we will lose some accuracy but will correct it the next
2943 * time we load the space map.
2944 */
2945 space_map_histogram_add(msp->ms_sm, msp->ms_freeing, tx);
2946 metaslab_aux_histograms_update(msp);
2947
2948 metaslab_group_histogram_add(mg, msp);
2949 metaslab_group_histogram_verify(mg);
2950 metaslab_class_histogram_verify(mg->mg_class);
2951
2952 /*
2953 * For sync pass 1, we avoid traversing this txg's free range tree
2954 * and instead will just swap the pointers for freeing and freed.
2955 * We can safely do this since the freed_tree is guaranteed to be
2956 * empty on the initial pass.
2957 */
2958 if (spa_sync_pass(spa) == 1) {
2959 range_tree_swap(&msp->ms_freeing, &msp->ms_freed);
2960 ASSERT0(msp->ms_allocated_this_txg);
2961 } else {
2962 range_tree_vacate(msp->ms_freeing,
2963 range_tree_add, msp->ms_freed);
2964 }
2965 msp->ms_allocated_this_txg += range_tree_space(alloctree);
2966 range_tree_vacate(alloctree, NULL, NULL);
2967
2968 ASSERT0(range_tree_space(msp->ms_allocating[txg & TXG_MASK]));
2969 ASSERT0(range_tree_space(msp->ms_allocating[TXG_CLEAN(txg)
2970 & TXG_MASK]));
2971 ASSERT0(range_tree_space(msp->ms_freeing));
2972 ASSERT0(range_tree_space(msp->ms_checkpointing));
2973
2974 mutex_exit(&msp->ms_lock);
2975
2976 if (object != space_map_object(msp->ms_sm)) {
2977 object = space_map_object(msp->ms_sm);
2978 dmu_write(mos, vd->vdev_ms_array, sizeof (uint64_t) *
2979 msp->ms_id, sizeof (uint64_t), &object, tx);
2980 }
2981 mutex_exit(&msp->ms_sync_lock);
2982 dmu_tx_commit(tx);
2983 }
2984
2985 /*
2986 * Called after a transaction group has completely synced to mark
2987 * all of the metaslab's free space as usable.
2988 */
2989 void
2990 metaslab_sync_done(metaslab_t *msp, uint64_t txg)
2991 {
2992 metaslab_group_t *mg = msp->ms_group;
2993 vdev_t *vd = mg->mg_vd;
2994 spa_t *spa = vd->vdev_spa;
2995 range_tree_t **defer_tree;
2996 int64_t alloc_delta, defer_delta;
2997 boolean_t defer_allowed = B_TRUE;
2998
2999 ASSERT(!vd->vdev_ishole);
3000
3001 mutex_enter(&msp->ms_lock);
3002
3003 /*
3004 * If this metaslab is just becoming available, initialize its
3005 * range trees and add its capacity to the vdev.
3006 */
3007 if (msp->ms_freed == NULL) {
3008 for (int t = 0; t < TXG_SIZE; t++) {
3009 ASSERT(msp->ms_allocating[t] == NULL);
3010
3011 msp->ms_allocating[t] = range_tree_create(NULL, NULL);
3012 }
3013
3014 ASSERT3P(msp->ms_freeing, ==, NULL);
3015 msp->ms_freeing = range_tree_create(NULL, NULL);
3016
3017 ASSERT3P(msp->ms_freed, ==, NULL);
3018 msp->ms_freed = range_tree_create(NULL, NULL);
3019
3020 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
3021 ASSERT(msp->ms_defer[t] == NULL);
3022
3023 msp->ms_defer[t] = range_tree_create(NULL, NULL);
3024 }
3025
3026 ASSERT3P(msp->ms_checkpointing, ==, NULL);
3027 msp->ms_checkpointing = range_tree_create(NULL, NULL);
3028
3029 metaslab_space_update(vd, mg->mg_class, 0, 0, msp->ms_size);
3030 }
3031 ASSERT0(range_tree_space(msp->ms_freeing));
3032 ASSERT0(range_tree_space(msp->ms_checkpointing));
3033
3034 defer_tree = &msp->ms_defer[txg % TXG_DEFER_SIZE];
3035
3036 uint64_t free_space = metaslab_class_get_space(spa_normal_class(spa)) -
3037 metaslab_class_get_alloc(spa_normal_class(spa));
3038 if (free_space <= spa_get_slop_space(spa) || vd->vdev_removing) {
3039 defer_allowed = B_FALSE;
3040 }
3041
3042 defer_delta = 0;
3043 alloc_delta = msp->ms_allocated_this_txg -
3044 range_tree_space(msp->ms_freed);
3045 if (defer_allowed) {
3046 defer_delta = range_tree_space(msp->ms_freed) -
3047 range_tree_space(*defer_tree);
3048 } else {
3049 defer_delta -= range_tree_space(*defer_tree);
3050 }
3051
3052 metaslab_space_update(vd, mg->mg_class, alloc_delta + defer_delta,
3053 defer_delta, 0);
3054
3055 /*
3056 * If there's a metaslab_load() in progress, wait for it to complete
3057 * so that we have a consistent view of the in-core space map.
3058 */
3059 metaslab_load_wait(msp);
3060
3061 /*
3062 * Move the frees from the defer_tree back to the free
3063 * range tree (if it's loaded). Swap the freed_tree and
3064 * the defer_tree -- this is safe to do because we've
3065 * just emptied out the defer_tree.
3066 */
3067 range_tree_vacate(*defer_tree,
3068 msp->ms_loaded ? range_tree_add : NULL, msp->ms_allocatable);
3069 if (defer_allowed) {
3070 range_tree_swap(&msp->ms_freed, defer_tree);
3071 } else {
3072 range_tree_vacate(msp->ms_freed,
3073 msp->ms_loaded ? range_tree_add : NULL,
3074 msp->ms_allocatable);
3075 }
3076
3077 msp->ms_synced_length = space_map_length(msp->ms_sm);
3078
3079 msp->ms_deferspace += defer_delta;
3080 ASSERT3S(msp->ms_deferspace, >=, 0);
3081 ASSERT3S(msp->ms_deferspace, <=, msp->ms_size);
3082 if (msp->ms_deferspace != 0) {
3083 /*
3084 * Keep syncing this metaslab until all deferred frees
3085 * are back in circulation.
3086 */
3087 vdev_dirty(vd, VDD_METASLAB, msp, txg + 1);
3088 }
3089 metaslab_aux_histograms_update_done(msp, defer_allowed);
3090
3091 if (msp->ms_new) {
3092 msp->ms_new = B_FALSE;
3093 mutex_enter(&mg->mg_lock);
3094 mg->mg_ms_ready++;
3095 mutex_exit(&mg->mg_lock);
3096 }
3097
3098 /*
3099 * Re-sort metaslab within its group now that we've adjusted
3100 * its allocatable space.
3101 */
3102 metaslab_recalculate_weight_and_sort(msp);
3103
3104 /*
3105 * If the metaslab is loaded and we've not tried to load or allocate
3106 * from it in 'metaslab_unload_delay' txgs, then unload it.
3107 */
3108 if (msp->ms_loaded &&
3109 msp->ms_initializing == 0 &&
3110 msp->ms_selected_txg + metaslab_unload_delay < txg) {
3111 for (int t = 1; t < TXG_CONCURRENT_STATES; t++) {
3112 VERIFY0(range_tree_space(
3113 msp->ms_allocating[(txg + t) & TXG_MASK]));
3114 }
3115 if (msp->ms_allocator != -1) {
3116 metaslab_passivate(msp, msp->ms_weight &
3117 ~METASLAB_ACTIVE_MASK);
3118 }
3119
3120 if (!metaslab_debug_unload)
3121 metaslab_unload(msp);
3122 }
3123
3124 ASSERT0(range_tree_space(msp->ms_allocating[txg & TXG_MASK]));
3125 ASSERT0(range_tree_space(msp->ms_freeing));
3126 ASSERT0(range_tree_space(msp->ms_freed));
3127 ASSERT0(range_tree_space(msp->ms_checkpointing));
3128
3129 msp->ms_allocated_this_txg = 0;
3130 mutex_exit(&msp->ms_lock);
3131 }
3132
3133 void
3134 metaslab_sync_reassess(metaslab_group_t *mg)
3135 {
3136 spa_t *spa = mg->mg_class->mc_spa;
3137
3138 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
3139 metaslab_group_alloc_update(mg);
3140 mg->mg_fragmentation = metaslab_group_fragmentation(mg);
3141
3142 /*
3143 * Preload the next potential metaslabs but only on active
3144 * metaslab groups. We can get into a state where the metaslab
3145 * is no longer active since we dirty metaslabs as we remove a
3146 * a device, thus potentially making the metaslab group eligible
3147 * for preloading.
3148 */
3149 if (mg->mg_activation_count > 0) {
3150 metaslab_group_preload(mg);
3151 }
3152 spa_config_exit(spa, SCL_ALLOC, FTAG);
3153 }
3154
3155 /*
3156 * When writing a ditto block (i.e. more than one DVA for a given BP) on
3157 * the same vdev as an existing DVA of this BP, then try to allocate it
3158 * on a different metaslab than existing DVAs (i.e. a unique metaslab).
3159 */
3160 static boolean_t
3161 metaslab_is_unique(metaslab_t *msp, dva_t *dva)
3162 {
3163 uint64_t dva_ms_id;
3164
3165 if (DVA_GET_ASIZE(dva) == 0)
3166 return (B_TRUE);
3167
3168 if (msp->ms_group->mg_vd->vdev_id != DVA_GET_VDEV(dva))
3169 return (B_TRUE);
3170
3171 dva_ms_id = DVA_GET_OFFSET(dva) >> msp->ms_group->mg_vd->vdev_ms_shift;
3172
3173 return (msp->ms_id != dva_ms_id);
3174 }
3175
3176 /*
3177 * ==========================================================================
3178 * Metaslab allocation tracing facility
3179 * ==========================================================================
3180 */
3181 kstat_t *metaslab_trace_ksp;
3182 kstat_named_t metaslab_trace_over_limit;
3183
3184 void
3185 metaslab_alloc_trace_init(void)
3186 {
3187 ASSERT(metaslab_alloc_trace_cache == NULL);
3188 metaslab_alloc_trace_cache = kmem_cache_create(
3189 "metaslab_alloc_trace_cache", sizeof (metaslab_alloc_trace_t),
3190 0, NULL, NULL, NULL, NULL, NULL, 0);
3191 metaslab_trace_ksp = kstat_create("zfs", 0, "metaslab_trace_stats",
3192 "misc", KSTAT_TYPE_NAMED, 1, KSTAT_FLAG_VIRTUAL);
3193 if (metaslab_trace_ksp != NULL) {
3194 metaslab_trace_ksp->ks_data = &metaslab_trace_over_limit;
3195 kstat_named_init(&metaslab_trace_over_limit,
3196 "metaslab_trace_over_limit", KSTAT_DATA_UINT64);
3197 kstat_install(metaslab_trace_ksp);
3198 }
3199 }
3200
3201 void
3202 metaslab_alloc_trace_fini(void)
3203 {
3204 if (metaslab_trace_ksp != NULL) {
3205 kstat_delete(metaslab_trace_ksp);
3206 metaslab_trace_ksp = NULL;
3207 }
3208 kmem_cache_destroy(metaslab_alloc_trace_cache);
3209 metaslab_alloc_trace_cache = NULL;
3210 }
3211
3212 /*
3213 * Add an allocation trace element to the allocation tracing list.
3214 */
3215 static void
3216 metaslab_trace_add(zio_alloc_list_t *zal, metaslab_group_t *mg,
3217 metaslab_t *msp, uint64_t psize, uint32_t dva_id, uint64_t offset,
3218 int allocator)
3219 {
3220 if (!metaslab_trace_enabled)
3221 return;
3222
3223 /*
3224 * When the tracing list reaches its maximum we remove
3225 * the second element in the list before adding a new one.
3226 * By removing the second element we preserve the original
3227 * entry as a clue to what allocations steps have already been
3228 * performed.
3229 */
3230 if (zal->zal_size == metaslab_trace_max_entries) {
3231 metaslab_alloc_trace_t *mat_next;
3232 #ifdef DEBUG
3233 panic("too many entries in allocation list");
3234 #endif
3235 atomic_inc_64(&metaslab_trace_over_limit.value.ui64);
3236 zal->zal_size--;
3237 mat_next = list_next(&zal->zal_list, list_head(&zal->zal_list));
3238 list_remove(&zal->zal_list, mat_next);
3239 kmem_cache_free(metaslab_alloc_trace_cache, mat_next);
3240 }
3241
3242 metaslab_alloc_trace_t *mat =
3243 kmem_cache_alloc(metaslab_alloc_trace_cache, KM_SLEEP);
3244 list_link_init(&mat->mat_list_node);
3245 mat->mat_mg = mg;
3246 mat->mat_msp = msp;
3247 mat->mat_size = psize;
3248 mat->mat_dva_id = dva_id;
3249 mat->mat_offset = offset;
3250 mat->mat_weight = 0;
3251 mat->mat_allocator = allocator;
3252
3253 if (msp != NULL)
3254 mat->mat_weight = msp->ms_weight;
3255
3256 /*
3257 * The list is part of the zio so locking is not required. Only
3258 * a single thread will perform allocations for a given zio.
3259 */
3260 list_insert_tail(&zal->zal_list, mat);
3261 zal->zal_size++;
3262
3263 ASSERT3U(zal->zal_size, <=, metaslab_trace_max_entries);
3264 }
3265
3266 void
3267 metaslab_trace_init(zio_alloc_list_t *zal)
3268 {
3269 list_create(&zal->zal_list, sizeof (metaslab_alloc_trace_t),
3270 offsetof(metaslab_alloc_trace_t, mat_list_node));
3271 zal->zal_size = 0;
3272 }
3273
3274 void
3275 metaslab_trace_fini(zio_alloc_list_t *zal)
3276 {
3277 metaslab_alloc_trace_t *mat;
3278
3279 while ((mat = list_remove_head(&zal->zal_list)) != NULL)
3280 kmem_cache_free(metaslab_alloc_trace_cache, mat);
3281 list_destroy(&zal->zal_list);
3282 zal->zal_size = 0;
3283 }
3284
3285 /*
3286 * ==========================================================================
3287 * Metaslab block operations
3288 * ==========================================================================
3289 */
3290
3291 static void
3292 metaslab_group_alloc_increment(spa_t *spa, uint64_t vdev, void *tag, int flags,
3293 int allocator)
3294 {
3295 if (!(flags & METASLAB_ASYNC_ALLOC) ||
3296 (flags & METASLAB_DONT_THROTTLE))
3297 return;
3298
3299 metaslab_group_t *mg = vdev_lookup_top(spa, vdev)->vdev_mg;
3300 if (!mg->mg_class->mc_alloc_throttle_enabled)
3301 return;
3302
3303 (void) zfs_refcount_add(&mg->mg_alloc_queue_depth[allocator], tag);
3304 }
3305
3306 static void
3307 metaslab_group_increment_qdepth(metaslab_group_t *mg, int allocator)
3308 {
3309 uint64_t max = mg->mg_max_alloc_queue_depth;
3310 uint64_t cur = mg->mg_cur_max_alloc_queue_depth[allocator];
3311 while (cur < max) {
3312 if (atomic_cas_64(&mg->mg_cur_max_alloc_queue_depth[allocator],
3313 cur, cur + 1) == cur) {
3314 atomic_inc_64(
3315 &mg->mg_class->mc_alloc_max_slots[allocator]);
3316 return;
3317 }
3318 cur = mg->mg_cur_max_alloc_queue_depth[allocator];
3319 }
3320 }
3321
3322 void
3323 metaslab_group_alloc_decrement(spa_t *spa, uint64_t vdev, void *tag, int flags,
3324 int allocator, boolean_t io_complete)
3325 {
3326 if (!(flags & METASLAB_ASYNC_ALLOC) ||
3327 (flags & METASLAB_DONT_THROTTLE))
3328 return;
3329
3330 metaslab_group_t *mg = vdev_lookup_top(spa, vdev)->vdev_mg;
3331 if (!mg->mg_class->mc_alloc_throttle_enabled)
3332 return;
3333
3334 (void) zfs_refcount_remove(&mg->mg_alloc_queue_depth[allocator], tag);
3335 if (io_complete)
3336 metaslab_group_increment_qdepth(mg, allocator);
3337 }
3338
3339 void
3340 metaslab_group_alloc_verify(spa_t *spa, const blkptr_t *bp, void *tag,
3341 int allocator)
3342 {
3343 #ifdef ZFS_DEBUG
3344 const dva_t *dva = bp->blk_dva;
3345 int ndvas = BP_GET_NDVAS(bp);
3346
3347 for (int d = 0; d < ndvas; d++) {
3348 uint64_t vdev = DVA_GET_VDEV(&dva[d]);
3349 metaslab_group_t *mg = vdev_lookup_top(spa, vdev)->vdev_mg;
3350 VERIFY(zfs_refcount_not_held(
3351 &mg->mg_alloc_queue_depth[allocator], tag));
3352 }
3353 #endif
3354 }
3355
3356 static uint64_t
3357 metaslab_block_alloc(metaslab_t *msp, uint64_t size, uint64_t txg)
3358 {
3359 uint64_t start;
3360 range_tree_t *rt = msp->ms_allocatable;
3361 metaslab_class_t *mc = msp->ms_group->mg_class;
3362
3363 VERIFY(!msp->ms_condensing);
3364 VERIFY0(msp->ms_initializing);
3365
3366 start = mc->mc_ops->msop_alloc(msp, size);
3367 if (start != -1ULL) {
3368 metaslab_group_t *mg = msp->ms_group;
3369 vdev_t *vd = mg->mg_vd;
3370
3371 VERIFY0(P2PHASE(start, 1ULL << vd->vdev_ashift));
3372 VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift));
3373 VERIFY3U(range_tree_space(rt) - size, <=, msp->ms_size);
3374 range_tree_remove(rt, start, size);
3375
3376 if (range_tree_is_empty(msp->ms_allocating[txg & TXG_MASK]))
3377 vdev_dirty(mg->mg_vd, VDD_METASLAB, msp, txg);
3378
3379 range_tree_add(msp->ms_allocating[txg & TXG_MASK], start, size);
3380
3381 /* Track the last successful allocation */
3382 msp->ms_alloc_txg = txg;
3383 metaslab_verify_space(msp, txg);
3384 }
3385
3386 /*
3387 * Now that we've attempted the allocation we need to update the
3388 * metaslab's maximum block size since it may have changed.
3389 */
3390 msp->ms_max_size = metaslab_block_maxsize(msp);
3391 return (start);
3392 }
3393
3394 /*
3395 * Find the metaslab with the highest weight that is less than what we've
3396 * already tried. In the common case, this means that we will examine each
3397 * metaslab at most once. Note that concurrent callers could reorder metaslabs
3398 * by activation/passivation once we have dropped the mg_lock. If a metaslab is
3399 * activated by another thread, and we fail to allocate from the metaslab we
3400 * have selected, we may not try the newly-activated metaslab, and instead
3401 * activate another metaslab. This is not optimal, but generally does not cause
3402 * any problems (a possible exception being if every metaslab is completely full
3403 * except for the the newly-activated metaslab which we fail to examine).
3404 */
3405 static metaslab_t *
3406 find_valid_metaslab(metaslab_group_t *mg, uint64_t activation_weight,
3407 dva_t *dva, int d, boolean_t want_unique, uint64_t asize, int allocator,
3408 zio_alloc_list_t *zal, metaslab_t *search, boolean_t *was_active)
3409 {
3410 avl_index_t idx;
3411 avl_tree_t *t = &mg->mg_metaslab_tree;
3412 metaslab_t *msp = avl_find(t, search, &idx);
3413 if (msp == NULL)
3414 msp = avl_nearest(t, idx, AVL_AFTER);
3415
3416 for (; msp != NULL; msp = AVL_NEXT(t, msp)) {
3417 int i;
3418 if (!metaslab_should_allocate(msp, asize)) {
3419 metaslab_trace_add(zal, mg, msp, asize, d,
3420 TRACE_TOO_SMALL, allocator);
3421 continue;
3422 }
3423
3424 /*
3425 * If the selected metaslab is condensing or being
3426 * initialized, skip it.
3427 */
3428 if (msp->ms_condensing || msp->ms_initializing > 0)
3429 continue;
3430
3431 *was_active = msp->ms_allocator != -1;
3432 /*
3433 * If we're activating as primary, this is our first allocation
3434 * from this disk, so we don't need to check how close we are.
3435 * If the metaslab under consideration was already active,
3436 * we're getting desperate enough to steal another allocator's
3437 * metaslab, so we still don't care about distances.
3438 */
3439 if (activation_weight == METASLAB_WEIGHT_PRIMARY || *was_active)
3440 break;
3441
3442 for (i = 0; i < d; i++) {
3443 if (want_unique &&
3444 !metaslab_is_unique(msp, &dva[i]))
3445 break; /* try another metaslab */
3446 }
3447 if (i == d)
3448 break;
3449 }
3450
3451 if (msp != NULL) {
3452 search->ms_weight = msp->ms_weight;
3453 search->ms_start = msp->ms_start + 1;
3454 search->ms_allocator = msp->ms_allocator;
3455 search->ms_primary = msp->ms_primary;
3456 }
3457 return (msp);
3458 }
3459
3460 /* ARGSUSED */
3461 static uint64_t
3462 metaslab_group_alloc_normal(metaslab_group_t *mg, zio_alloc_list_t *zal,
3463 uint64_t asize, uint64_t txg, boolean_t want_unique, dva_t *dva,
3464 int d, int allocator)
3465 {
3466 metaslab_t *msp = NULL;
3467 uint64_t offset = -1ULL;
3468 uint64_t activation_weight;
3469
3470 activation_weight = METASLAB_WEIGHT_PRIMARY;
3471 for (int i = 0; i < d; i++) {
3472 if (activation_weight == METASLAB_WEIGHT_PRIMARY &&
3473 DVA_GET_VDEV(&dva[i]) == mg->mg_vd->vdev_id) {
3474 activation_weight = METASLAB_WEIGHT_SECONDARY;
3475 } else if (activation_weight == METASLAB_WEIGHT_SECONDARY &&
3476 DVA_GET_VDEV(&dva[i]) == mg->mg_vd->vdev_id) {
3477 activation_weight = METASLAB_WEIGHT_CLAIM;
3478 break;
3479 }
3480 }
3481
3482 /*
3483 * If we don't have enough metaslabs active to fill the entire array, we
3484 * just use the 0th slot.
3485 */
3486 if (mg->mg_ms_ready < mg->mg_allocators * 3)
3487 allocator = 0;
3488
3489 ASSERT3U(mg->mg_vd->vdev_ms_count, >=, 2);
3490
3491 metaslab_t *search = kmem_alloc(sizeof (*search), KM_SLEEP);
3492 search->ms_weight = UINT64_MAX;
3493 search->ms_start = 0;
3494 /*
3495 * At the end of the metaslab tree are the already-active metaslabs,
3496 * first the primaries, then the secondaries. When we resume searching
3497 * through the tree, we need to consider ms_allocator and ms_primary so
3498 * we start in the location right after where we left off, and don't
3499 * accidentally loop forever considering the same metaslabs.
3500 */
3501 search->ms_allocator = -1;
3502 search->ms_primary = B_TRUE;
3503 for (;;) {
3504 boolean_t was_active = B_FALSE;
3505
3506 mutex_enter(&mg->mg_lock);
3507
3508 if (activation_weight == METASLAB_WEIGHT_PRIMARY &&
3509 mg->mg_primaries[allocator] != NULL) {
3510 msp = mg->mg_primaries[allocator];
3511 was_active = B_TRUE;
3512 } else if (activation_weight == METASLAB_WEIGHT_SECONDARY &&
3513 mg->mg_secondaries[allocator] != NULL) {
3514 msp = mg->mg_secondaries[allocator];
3515 was_active = B_TRUE;
3516 } else {
3517 msp = find_valid_metaslab(mg, activation_weight, dva, d,
3518 want_unique, asize, allocator, zal, search,
3519 &was_active);
3520 }
3521
3522 mutex_exit(&mg->mg_lock);
3523 if (msp == NULL) {
3524 kmem_free(search, sizeof (*search));
3525 return (-1ULL);
3526 }
3527
3528 mutex_enter(&msp->ms_lock);
3529 /*
3530 * Ensure that the metaslab we have selected is still
3531 * capable of handling our request. It's possible that
3532 * another thread may have changed the weight while we
3533 * were blocked on the metaslab lock. We check the
3534 * active status first to see if we need to reselect
3535 * a new metaslab.
3536 */
3537 if (was_active && !(msp->ms_weight & METASLAB_ACTIVE_MASK)) {
3538 mutex_exit(&msp->ms_lock);
3539 continue;
3540 }
3541
3542 /*
3543 * If the metaslab is freshly activated for an allocator that
3544 * isn't the one we're allocating from, or if it's a primary and
3545 * we're seeking a secondary (or vice versa), we go back and
3546 * select a new metaslab.
3547 */
3548 if (!was_active && (msp->ms_weight & METASLAB_ACTIVE_MASK) &&
3549 (msp->ms_allocator != -1) &&
3550 (msp->ms_allocator != allocator || ((activation_weight ==
3551 METASLAB_WEIGHT_PRIMARY) != msp->ms_primary))) {
3552 mutex_exit(&msp->ms_lock);
3553 continue;
3554 }
3555
3556 if (msp->ms_weight & METASLAB_WEIGHT_CLAIM &&
3557 activation_weight != METASLAB_WEIGHT_CLAIM) {
3558 metaslab_passivate(msp, msp->ms_weight &
3559 ~METASLAB_WEIGHT_CLAIM);
3560 mutex_exit(&msp->ms_lock);
3561 continue;
3562 }
3563
3564 if (metaslab_activate(msp, allocator, activation_weight) != 0) {
3565 mutex_exit(&msp->ms_lock);
3566 continue;
3567 }
3568
3569 msp->ms_selected_txg = txg;
3570
3571 /*
3572 * Now that we have the lock, recheck to see if we should
3573 * continue to use this metaslab for this allocation. The
3574 * the metaslab is now loaded so metaslab_should_allocate() can
3575 * accurately determine if the allocation attempt should
3576 * proceed.
3577 */
3578 if (!metaslab_should_allocate(msp, asize)) {
3579 /* Passivate this metaslab and select a new one. */
3580 metaslab_trace_add(zal, mg, msp, asize, d,
3581 TRACE_TOO_SMALL, allocator);
3582 goto next;
3583 }
3584
3585 /*
3586 * If this metaslab is currently condensing then pick again as
3587 * we can't manipulate this metaslab until it's committed
3588 * to disk. If this metaslab is being initialized, we shouldn't
3589 * allocate from it since the allocated region might be
3590 * overwritten after allocation.
3591 */
3592 if (msp->ms_condensing) {
3593 metaslab_trace_add(zal, mg, msp, asize, d,
3594 TRACE_CONDENSING, allocator);
3595 metaslab_passivate(msp, msp->ms_weight &
3596 ~METASLAB_ACTIVE_MASK);
3597 mutex_exit(&msp->ms_lock);
3598 continue;
3599 } else if (msp->ms_initializing > 0) {
3600 metaslab_trace_add(zal, mg, msp, asize, d,
3601 TRACE_INITIALIZING, allocator);
3602 metaslab_passivate(msp, msp->ms_weight &
3603 ~METASLAB_ACTIVE_MASK);
3604 mutex_exit(&msp->ms_lock);
3605 continue;
3606 }
3607
3608 offset = metaslab_block_alloc(msp, asize, txg);
3609 metaslab_trace_add(zal, mg, msp, asize, d, offset, allocator);
3610
3611 if (offset != -1ULL) {
3612 /* Proactively passivate the metaslab, if needed */
3613 metaslab_segment_may_passivate(msp);
3614 break;
3615 }
3616 next:
3617 ASSERT(msp->ms_loaded);
3618
3619 /*
3620 * We were unable to allocate from this metaslab so determine
3621 * a new weight for this metaslab. Now that we have loaded
3622 * the metaslab we can provide a better hint to the metaslab
3623 * selector.
3624 *
3625 * For space-based metaslabs, we use the maximum block size.
3626 * This information is only available when the metaslab
3627 * is loaded and is more accurate than the generic free
3628 * space weight that was calculated by metaslab_weight().
3629 * This information allows us to quickly compare the maximum
3630 * available allocation in the metaslab to the allocation
3631 * size being requested.
3632 *
3633 * For segment-based metaslabs, determine the new weight
3634 * based on the highest bucket in the range tree. We
3635 * explicitly use the loaded segment weight (i.e. the range
3636 * tree histogram) since it contains the space that is
3637 * currently available for allocation and is accurate
3638 * even within a sync pass.
3639 */
3640 if (WEIGHT_IS_SPACEBASED(msp->ms_weight)) {
3641 uint64_t weight = metaslab_block_maxsize(msp);
3642 WEIGHT_SET_SPACEBASED(weight);
3643 metaslab_passivate(msp, weight);
3644 } else {
3645 metaslab_passivate(msp,
3646 metaslab_weight_from_range_tree(msp));
3647 }
3648
3649 /*
3650 * We have just failed an allocation attempt, check
3651 * that metaslab_should_allocate() agrees. Otherwise,
3652 * we may end up in an infinite loop retrying the same
3653 * metaslab.
3654 */
3655 ASSERT(!metaslab_should_allocate(msp, asize));
3656
3657 mutex_exit(&msp->ms_lock);
3658 }
3659 mutex_exit(&msp->ms_lock);
3660 kmem_free(search, sizeof (*search));
3661 return (offset);
3662 }
3663
3664 static uint64_t
3665 metaslab_group_alloc(metaslab_group_t *mg, zio_alloc_list_t *zal,
3666 uint64_t asize, uint64_t txg, boolean_t want_unique, dva_t *dva,
3667 int d, int allocator)
3668 {
3669 uint64_t offset;
3670 ASSERT(mg->mg_initialized);
3671
3672 offset = metaslab_group_alloc_normal(mg, zal, asize, txg, want_unique,
3673 dva, d, allocator);
3674
3675 mutex_enter(&mg->mg_lock);
3676 if (offset == -1ULL) {
3677 mg->mg_failed_allocations++;
3678 metaslab_trace_add(zal, mg, NULL, asize, d,
3679 TRACE_GROUP_FAILURE, allocator);
3680 if (asize == SPA_GANGBLOCKSIZE) {
3681 /*
3682 * This metaslab group was unable to allocate
3683 * the minimum gang block size so it must be out of
3684 * space. We must notify the allocation throttle
3685 * to start skipping allocation attempts to this
3686 * metaslab group until more space becomes available.
3687 * Note: this failure cannot be caused by the
3688 * allocation throttle since the allocation throttle
3689 * is only responsible for skipping devices and
3690 * not failing block allocations.
3691 */
3692 mg->mg_no_free_space = B_TRUE;
3693 }
3694 }
3695 mg->mg_allocations++;
3696 mutex_exit(&mg->mg_lock);
3697 return (offset);
3698 }
3699
3700 /*
3701 * Allocate a block for the specified i/o.
3702 */
3703 int
3704 metaslab_alloc_dva(spa_t *spa, metaslab_class_t *mc, uint64_t psize,
3705 dva_t *dva, int d, dva_t *hintdva, uint64_t txg, int flags,
3706 zio_alloc_list_t *zal, int allocator)
3707 {
3708 metaslab_group_t *mg, *rotor;
3709 vdev_t *vd;
3710 boolean_t try_hard = B_FALSE;
3711
3712 ASSERT(!DVA_IS_VALID(&dva[d]));
3713
3714 /*
3715 * For testing, make some blocks above a certain size be gang blocks.
3716 * This will also test spilling from special to normal.
3717 */
3718 if (psize >= metaslab_force_ganging && (ddi_get_lbolt() & 3) == 0) {
3719 metaslab_trace_add(zal, NULL, NULL, psize, d, TRACE_FORCE_GANG,
3720 allocator);
3721 return (SET_ERROR(ENOSPC));
3722 }
3723
3724 /*
3725 * Start at the rotor and loop through all mgs until we find something.
3726 * Note that there's no locking on mc_rotor or mc_aliquot because
3727 * nothing actually breaks if we miss a few updates -- we just won't
3728 * allocate quite as evenly. It all balances out over time.
3729 *
3730 * If we are doing ditto or log blocks, try to spread them across
3731 * consecutive vdevs. If we're forced to reuse a vdev before we've
3732 * allocated all of our ditto blocks, then try and spread them out on
3733 * that vdev as much as possible. If it turns out to not be possible,
3734 * gradually lower our standards until anything becomes acceptable.
3735 * Also, allocating on consecutive vdevs (as opposed to random vdevs)
3736 * gives us hope of containing our fault domains to something we're
3737 * able to reason about. Otherwise, any two top-level vdev failures
3738 * will guarantee the loss of data. With consecutive allocation,
3739 * only two adjacent top-level vdev failures will result in data loss.
3740 *
3741 * If we are doing gang blocks (hintdva is non-NULL), try to keep
3742 * ourselves on the same vdev as our gang block header. That
3743 * way, we can hope for locality in vdev_cache, plus it makes our
3744 * fault domains something tractable.
3745 */
3746 if (hintdva) {
3747 vd = vdev_lookup_top(spa, DVA_GET_VDEV(&hintdva[d]));
3748
3749 /*
3750 * It's possible the vdev we're using as the hint no
3751 * longer exists or its mg has been closed (e.g. by
3752 * device removal). Consult the rotor when
3753 * all else fails.
3754 */
3755 if (vd != NULL && vd->vdev_mg != NULL) {
3756 mg = vd->vdev_mg;
3757
3758 if (flags & METASLAB_HINTBP_AVOID &&
3759 mg->mg_next != NULL)
3760 mg = mg->mg_next;
3761 } else {
3762 mg = mc->mc_rotor;
3763 }
3764 } else if (d != 0) {
3765 vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[d - 1]));
3766 mg = vd->vdev_mg->mg_next;
3767 } else {
3768 ASSERT(mc->mc_rotor != NULL);
3769 mg = mc->mc_rotor;
3770 }
3771
3772 /*
3773 * If the hint put us into the wrong metaslab class, or into a
3774 * metaslab group that has been passivated, just follow the rotor.
3775 */
3776 if (mg->mg_class != mc || mg->mg_activation_count <= 0)
3777 mg = mc->mc_rotor;
3778
3779 rotor = mg;
3780 top:
3781 do {
3782 boolean_t allocatable;
3783
3784 ASSERT(mg->mg_activation_count == 1);
3785 vd = mg->mg_vd;
3786
3787 /*
3788 * Don't allocate from faulted devices.
3789 */
3790 if (try_hard) {
3791 spa_config_enter(spa, SCL_ZIO, FTAG, RW_READER);
3792 allocatable = vdev_allocatable(vd);
3793 spa_config_exit(spa, SCL_ZIO, FTAG);
3794 } else {
3795 allocatable = vdev_allocatable(vd);
3796 }
3797
3798 /*
3799 * Determine if the selected metaslab group is eligible
3800 * for allocations. If we're ganging then don't allow
3801 * this metaslab group to skip allocations since that would
3802 * inadvertently return ENOSPC and suspend the pool
3803 * even though space is still available.
3804 */
3805 if (allocatable && !GANG_ALLOCATION(flags) && !try_hard) {
3806 allocatable = metaslab_group_allocatable(mg, rotor,
3807 psize, allocator);
3808 }
3809
3810 if (!allocatable) {
3811 metaslab_trace_add(zal, mg, NULL, psize, d,
3812 TRACE_NOT_ALLOCATABLE, allocator);
3813 goto next;
3814 }
3815
3816 ASSERT(mg->mg_initialized);
3817
3818 /*
3819 * Avoid writing single-copy data to a failing,
3820 * non-redundant vdev, unless we've already tried all
3821 * other vdevs.
3822 */
3823 if ((vd->vdev_stat.vs_write_errors > 0 ||
3824 vd->vdev_state < VDEV_STATE_HEALTHY) &&
3825 d == 0 && !try_hard && vd->vdev_children == 0) {
3826 metaslab_trace_add(zal, mg, NULL, psize, d,
3827 TRACE_VDEV_ERROR, allocator);
3828 goto next;
3829 }
3830
3831 ASSERT(mg->mg_class == mc);
3832
3833 uint64_t asize = vdev_psize_to_asize(vd, psize);
3834 ASSERT(P2PHASE(asize, 1ULL << vd->vdev_ashift) == 0);
3835
3836 /*
3837 * If we don't need to try hard, then require that the
3838 * block be on an different metaslab from any other DVAs
3839 * in this BP (unique=true). If we are trying hard, then
3840 * allow any metaslab to be used (unique=false).
3841 */
3842 uint64_t offset = metaslab_group_alloc(mg, zal, asize, txg,
3843 !try_hard, dva, d, allocator);
3844
3845 if (offset != -1ULL) {
3846 /*
3847 * If we've just selected this metaslab group,
3848 * figure out whether the corresponding vdev is
3849 * over- or under-used relative to the pool,
3850 * and set an allocation bias to even it out.
3851 */
3852 if (mc->mc_aliquot == 0 && metaslab_bias_enabled) {
3853 vdev_stat_t *vs = &vd->vdev_stat;
3854 int64_t vu, cu;
3855
3856 vu = (vs->vs_alloc * 100) / (vs->vs_space + 1);
3857 cu = (mc->mc_alloc * 100) / (mc->mc_space + 1);
3858
3859 /*
3860 * Calculate how much more or less we should
3861 * try to allocate from this device during
3862 * this iteration around the rotor.
3863 * For example, if a device is 80% full
3864 * and the pool is 20% full then we should
3865 * reduce allocations by 60% on this device.
3866 *
3867 * mg_bias = (20 - 80) * 512K / 100 = -307K
3868 *
3869 * This reduces allocations by 307K for this
3870 * iteration.
3871 */
3872 mg->mg_bias = ((cu - vu) *
3873 (int64_t)mg->mg_aliquot) / 100;
3874 } else if (!metaslab_bias_enabled) {
3875 mg->mg_bias = 0;
3876 }
3877
3878 if (atomic_add_64_nv(&mc->mc_aliquot, asize) >=
3879 mg->mg_aliquot + mg->mg_bias) {
3880 mc->mc_rotor = mg->mg_next;
3881 mc->mc_aliquot = 0;
3882 }
3883
3884 DVA_SET_VDEV(&dva[d], vd->vdev_id);
3885 DVA_SET_OFFSET(&dva[d], offset);
3886 DVA_SET_GANG(&dva[d], !!(flags & METASLAB_GANG_HEADER));
3887 DVA_SET_ASIZE(&dva[d], asize);
3888
3889 return (0);
3890 }
3891 next:
3892 mc->mc_rotor = mg->mg_next;
3893 mc->mc_aliquot = 0;
3894 } while ((mg = mg->mg_next) != rotor);
3895
3896 /*
3897 * If we haven't tried hard, do so now.
3898 */
3899 if (!try_hard) {
3900 try_hard = B_TRUE;
3901 goto top;
3902 }
3903
3904 bzero(&dva[d], sizeof (dva_t));
3905
3906 metaslab_trace_add(zal, rotor, NULL, psize, d, TRACE_ENOSPC, allocator);
3907 return (SET_ERROR(ENOSPC));
3908 }
3909
3910 void
3911 metaslab_free_concrete(vdev_t *vd, uint64_t offset, uint64_t asize,
3912 boolean_t checkpoint)
3913 {
3914 metaslab_t *msp;
3915 spa_t *spa = vd->vdev_spa;
3916
3917 ASSERT(vdev_is_concrete(vd));
3918 ASSERT3U(spa_config_held(spa, SCL_ALL, RW_READER), !=, 0);
3919 ASSERT3U(offset >> vd->vdev_ms_shift, <, vd->vdev_ms_count);
3920
3921 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
3922
3923 VERIFY(!msp->ms_condensing);
3924 VERIFY3U(offset, >=, msp->ms_start);
3925 VERIFY3U(offset + asize, <=, msp->ms_start + msp->ms_size);
3926 VERIFY0(P2PHASE(offset, 1ULL << vd->vdev_ashift));
3927 VERIFY0(P2PHASE(asize, 1ULL << vd->vdev_ashift));
3928
3929 metaslab_check_free_impl(vd, offset, asize);
3930
3931 mutex_enter(&msp->ms_lock);
3932 if (range_tree_is_empty(msp->ms_freeing) &&
3933 range_tree_is_empty(msp->ms_checkpointing)) {
3934 vdev_dirty(vd, VDD_METASLAB, msp, spa_syncing_txg(spa));
3935 }
3936
3937 if (checkpoint) {
3938 ASSERT(spa_has_checkpoint(spa));
3939 range_tree_add(msp->ms_checkpointing, offset, asize);
3940 } else {
3941 range_tree_add(msp->ms_freeing, offset, asize);
3942 }
3943 mutex_exit(&msp->ms_lock);
3944 }
3945
3946 /* ARGSUSED */
3947 void
3948 metaslab_free_impl_cb(uint64_t inner_offset, vdev_t *vd, uint64_t offset,
3949 uint64_t size, void *arg)
3950 {
3951 boolean_t *checkpoint = arg;
3952
3953 ASSERT3P(checkpoint, !=, NULL);
3954
3955 if (vd->vdev_ops->vdev_op_remap != NULL)
3956 vdev_indirect_mark_obsolete(vd, offset, size);
3957 else
3958 metaslab_free_impl(vd, offset, size, *checkpoint);
3959 }
3960
3961 static void
3962 metaslab_free_impl(vdev_t *vd, uint64_t offset, uint64_t size,
3963 boolean_t checkpoint)
3964 {
3965 spa_t *spa = vd->vdev_spa;
3966
3967 ASSERT3U(spa_config_held(spa, SCL_ALL, RW_READER), !=, 0);
3968
3969 if (spa_syncing_txg(spa) > spa_freeze_txg(spa))
3970 return;
3971
3972 if (spa->spa_vdev_removal != NULL &&
3973 spa->spa_vdev_removal->svr_vdev_id == vd->vdev_id &&
3974 vdev_is_concrete(vd)) {
3975 /*
3976 * Note: we check if the vdev is concrete because when
3977 * we complete the removal, we first change the vdev to be
3978 * an indirect vdev (in open context), and then (in syncing
3979 * context) clear spa_vdev_removal.
3980 */
3981 free_from_removing_vdev(vd, offset, size);
3982 } else if (vd->vdev_ops->vdev_op_remap != NULL) {
3983 vdev_indirect_mark_obsolete(vd, offset, size);
3984 vd->vdev_ops->vdev_op_remap(vd, offset, size,
3985 metaslab_free_impl_cb, &checkpoint);
3986 } else {
3987 metaslab_free_concrete(vd, offset, size, checkpoint);
3988 }
3989 }
3990
3991 typedef struct remap_blkptr_cb_arg {
3992 blkptr_t *rbca_bp;
3993 spa_remap_cb_t rbca_cb;
3994 vdev_t *rbca_remap_vd;
3995 uint64_t rbca_remap_offset;
3996 void *rbca_cb_arg;
3997 } remap_blkptr_cb_arg_t;
3998
3999 void
4000 remap_blkptr_cb(uint64_t inner_offset, vdev_t *vd, uint64_t offset,
4001 uint64_t size, void *arg)
4002 {
4003 remap_blkptr_cb_arg_t *rbca = arg;
4004 blkptr_t *bp = rbca->rbca_bp;
4005
4006 /* We can not remap split blocks. */
4007 if (size != DVA_GET_ASIZE(&bp->blk_dva[0]))
4008 return;
4009 ASSERT0(inner_offset);
4010
4011 if (rbca->rbca_cb != NULL) {
4012 /*
4013 * At this point we know that we are not handling split
4014 * blocks and we invoke the callback on the previous
4015 * vdev which must be indirect.
4016 */
4017 ASSERT3P(rbca->rbca_remap_vd->vdev_ops, ==, &vdev_indirect_ops);
4018
4019 rbca->rbca_cb(rbca->rbca_remap_vd->vdev_id,
4020 rbca->rbca_remap_offset, size, rbca->rbca_cb_arg);
4021
4022 /* set up remap_blkptr_cb_arg for the next call */
4023 rbca->rbca_remap_vd = vd;
4024 rbca->rbca_remap_offset = offset;
4025 }
4026
4027 /*
4028 * The phys birth time is that of dva[0]. This ensures that we know
4029 * when each dva was written, so that resilver can determine which
4030 * blocks need to be scrubbed (i.e. those written during the time
4031 * the vdev was offline). It also ensures that the key used in
4032 * the ARC hash table is unique (i.e. dva[0] + phys_birth). If
4033 * we didn't change the phys_birth, a lookup in the ARC for a
4034 * remapped BP could find the data that was previously stored at
4035 * this vdev + offset.
4036 */
4037 vdev_t *oldvd = vdev_lookup_top(vd->vdev_spa,
4038 DVA_GET_VDEV(&bp->blk_dva[0]));
4039 vdev_indirect_births_t *vib = oldvd->vdev_indirect_births;
4040 bp->blk_phys_birth = vdev_indirect_births_physbirth(vib,
4041 DVA_GET_OFFSET(&bp->blk_dva[0]), DVA_GET_ASIZE(&bp->blk_dva[0]));
4042
4043 DVA_SET_VDEV(&bp->blk_dva[0], vd->vdev_id);
4044 DVA_SET_OFFSET(&bp->blk_dva[0], offset);
4045 }
4046
4047 /*
4048 * If the block pointer contains any indirect DVAs, modify them to refer to
4049 * concrete DVAs. Note that this will sometimes not be possible, leaving
4050 * the indirect DVA in place. This happens if the indirect DVA spans multiple
4051 * segments in the mapping (i.e. it is a "split block").
4052 *
4053 * If the BP was remapped, calls the callback on the original dva (note the
4054 * callback can be called multiple times if the original indirect DVA refers
4055 * to another indirect DVA, etc).
4056 *
4057 * Returns TRUE if the BP was remapped.
4058 */
4059 boolean_t
4060 spa_remap_blkptr(spa_t *spa, blkptr_t *bp, spa_remap_cb_t callback, void *arg)
4061 {
4062 remap_blkptr_cb_arg_t rbca;
4063
4064 if (!zfs_remap_blkptr_enable)
4065 return (B_FALSE);
4066
4067 if (!spa_feature_is_enabled(spa, SPA_FEATURE_OBSOLETE_COUNTS))
4068 return (B_FALSE);
4069
4070 /*
4071 * Dedup BP's can not be remapped, because ddt_phys_select() depends
4072 * on DVA[0] being the same in the BP as in the DDT (dedup table).
4073 */
4074 if (BP_GET_DEDUP(bp))
4075 return (B_FALSE);
4076
4077 /*
4078 * Gang blocks can not be remapped, because
4079 * zio_checksum_gang_verifier() depends on the DVA[0] that's in
4080 * the BP used to read the gang block header (GBH) being the same
4081 * as the DVA[0] that we allocated for the GBH.
4082 */
4083 if (BP_IS_GANG(bp))
4084 return (B_FALSE);
4085
4086 /*
4087 * Embedded BP's have no DVA to remap.
4088 */
4089 if (BP_GET_NDVAS(bp) < 1)
4090 return (B_FALSE);
4091
4092 /*
4093 * Note: we only remap dva[0]. If we remapped other dvas, we
4094 * would no longer know what their phys birth txg is.
4095 */
4096 dva_t *dva = &bp->blk_dva[0];
4097
4098 uint64_t offset = DVA_GET_OFFSET(dva);
4099 uint64_t size = DVA_GET_ASIZE(dva);
4100 vdev_t *vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
4101
4102 if (vd->vdev_ops->vdev_op_remap == NULL)
4103 return (B_FALSE);
4104
4105 rbca.rbca_bp = bp;
4106 rbca.rbca_cb = callback;
4107 rbca.rbca_remap_vd = vd;
4108 rbca.rbca_remap_offset = offset;
4109 rbca.rbca_cb_arg = arg;
4110
4111 /*
4112 * remap_blkptr_cb() will be called in order for each level of
4113 * indirection, until a concrete vdev is reached or a split block is
4114 * encountered. old_vd and old_offset are updated within the callback
4115 * as we go from the one indirect vdev to the next one (either concrete
4116 * or indirect again) in that order.
4117 */
4118 vd->vdev_ops->vdev_op_remap(vd, offset, size, remap_blkptr_cb, &rbca);
4119
4120 /* Check if the DVA wasn't remapped because it is a split block */
4121 if (DVA_GET_VDEV(&rbca.rbca_bp->blk_dva[0]) == vd->vdev_id)
4122 return (B_FALSE);
4123
4124 return (B_TRUE);
4125 }
4126
4127 /*
4128 * Undo the allocation of a DVA which happened in the given transaction group.
4129 */
4130 void
4131 metaslab_unalloc_dva(spa_t *spa, const dva_t *dva, uint64_t txg)
4132 {
4133 metaslab_t *msp;
4134 vdev_t *vd;
4135 uint64_t vdev = DVA_GET_VDEV(dva);
4136 uint64_t offset = DVA_GET_OFFSET(dva);
4137 uint64_t size = DVA_GET_ASIZE(dva);
4138
4139 ASSERT(DVA_IS_VALID(dva));
4140 ASSERT3U(spa_config_held(spa, SCL_ALL, RW_READER), !=, 0);
4141
4142 if (txg > spa_freeze_txg(spa))
4143 return;
4144
4145 if ((vd = vdev_lookup_top(spa, vdev)) == NULL ||
4146 (offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count) {
4147 cmn_err(CE_WARN, "metaslab_free_dva(): bad DVA %llu:%llu",
4148 (u_longlong_t)vdev, (u_longlong_t)offset);
4149 ASSERT(0);
4150 return;
4151 }
4152
4153 ASSERT(!vd->vdev_removing);
4154 ASSERT(vdev_is_concrete(vd));
4155 ASSERT0(vd->vdev_indirect_config.vic_mapping_object);
4156 ASSERT3P(vd->vdev_indirect_mapping, ==, NULL);
4157
4158 if (DVA_GET_GANG(dva))
4159 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
4160
4161 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
4162
4163 mutex_enter(&msp->ms_lock);
4164 range_tree_remove(msp->ms_allocating[txg & TXG_MASK],
4165 offset, size);
4166
4167 VERIFY(!msp->ms_condensing);
4168 VERIFY3U(offset, >=, msp->ms_start);
4169 VERIFY3U(offset + size, <=, msp->ms_start + msp->ms_size);
4170 VERIFY3U(range_tree_space(msp->ms_allocatable) + size, <=,
4171 msp->ms_size);
4172 VERIFY0(P2PHASE(offset, 1ULL << vd->vdev_ashift));
4173 VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift));
4174 range_tree_add(msp->ms_allocatable, offset, size);
4175 mutex_exit(&msp->ms_lock);
4176 }
4177
4178 /*
4179 * Free the block represented by the given DVA.
4180 */
4181 void
4182 metaslab_free_dva(spa_t *spa, const dva_t *dva, boolean_t checkpoint)
4183 {
4184 uint64_t vdev = DVA_GET_VDEV(dva);
4185 uint64_t offset = DVA_GET_OFFSET(dva);
4186 uint64_t size = DVA_GET_ASIZE(dva);
4187 vdev_t *vd = vdev_lookup_top(spa, vdev);
4188
4189 ASSERT(DVA_IS_VALID(dva));
4190 ASSERT3U(spa_config_held(spa, SCL_ALL, RW_READER), !=, 0);
4191
4192 if (DVA_GET_GANG(dva)) {
4193 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
4194 }
4195
4196 metaslab_free_impl(vd, offset, size, checkpoint);
4197 }
4198
4199 /*
4200 * Reserve some allocation slots. The reservation system must be called
4201 * before we call into the allocator. If there aren't any available slots
4202 * then the I/O will be throttled until an I/O completes and its slots are
4203 * freed up. The function returns true if it was successful in placing
4204 * the reservation.
4205 */
4206 boolean_t
4207 metaslab_class_throttle_reserve(metaslab_class_t *mc, int slots, int allocator,
4208 zio_t *zio, int flags)
4209 {
4210 uint64_t available_slots = 0;
4211 boolean_t slot_reserved = B_FALSE;
4212 uint64_t max = mc->mc_alloc_max_slots[allocator];
4213
4214 ASSERT(mc->mc_alloc_throttle_enabled);
4215 mutex_enter(&mc->mc_lock);
4216
4217 uint64_t reserved_slots =
4218 zfs_refcount_count(&mc->mc_alloc_slots[allocator]);
4219 if (reserved_slots < max)
4220 available_slots = max - reserved_slots;
4221
4222 if (slots <= available_slots || GANG_ALLOCATION(flags) ||
4223 flags & METASLAB_MUST_RESERVE) {
4224 /*
4225 * We reserve the slots individually so that we can unreserve
4226 * them individually when an I/O completes.
4227 */
4228 for (int d = 0; d < slots; d++) {
4229 reserved_slots =
4230 zfs_refcount_add(&mc->mc_alloc_slots[allocator],
4231 zio);
4232 }
4233 zio->io_flags |= ZIO_FLAG_IO_ALLOCATING;
4234 slot_reserved = B_TRUE;
4235 }
4236
4237 mutex_exit(&mc->mc_lock);
4238 return (slot_reserved);
4239 }
4240
4241 void
4242 metaslab_class_throttle_unreserve(metaslab_class_t *mc, int slots,
4243 int allocator, zio_t *zio)
4244 {
4245 ASSERT(mc->mc_alloc_throttle_enabled);
4246 mutex_enter(&mc->mc_lock);
4247 for (int d = 0; d < slots; d++) {
4248 (void) zfs_refcount_remove(&mc->mc_alloc_slots[allocator],
4249 zio);
4250 }
4251 mutex_exit(&mc->mc_lock);
4252 }
4253
4254 static int
4255 metaslab_claim_concrete(vdev_t *vd, uint64_t offset, uint64_t size,
4256 uint64_t txg)
4257 {
4258 metaslab_t *msp;
4259 spa_t *spa = vd->vdev_spa;
4260 int error = 0;
4261
4262 if (offset >> vd->vdev_ms_shift >= vd->vdev_ms_count)
4263 return (ENXIO);
4264
4265 ASSERT3P(vd->vdev_ms, !=, NULL);
4266 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
4267
4268 mutex_enter(&msp->ms_lock);
4269
4270 if ((txg != 0 && spa_writeable(spa)) || !msp->ms_loaded)
4271 error = metaslab_activate(msp, 0, METASLAB_WEIGHT_CLAIM);
4272 /*
4273 * No need to fail in that case; someone else has activated the
4274 * metaslab, but that doesn't preclude us from using it.
4275 */
4276 if (error == EBUSY)
4277 error = 0;
4278
4279 if (error == 0 &&
4280 !range_tree_contains(msp->ms_allocatable, offset, size))
4281 error = SET_ERROR(ENOENT);
4282
4283 if (error || txg == 0) { /* txg == 0 indicates dry run */
4284 mutex_exit(&msp->ms_lock);
4285 return (error);
4286 }
4287
4288 VERIFY(!msp->ms_condensing);
4289 VERIFY0(P2PHASE(offset, 1ULL << vd->vdev_ashift));
4290 VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift));
4291 VERIFY3U(range_tree_space(msp->ms_allocatable) - size, <=,
4292 msp->ms_size);
4293 range_tree_remove(msp->ms_allocatable, offset, size);
4294
4295 if (spa_writeable(spa)) { /* don't dirty if we're zdb(1M) */
4296 if (range_tree_is_empty(msp->ms_allocating[txg & TXG_MASK]))
4297 vdev_dirty(vd, VDD_METASLAB, msp, txg);
4298 range_tree_add(msp->ms_allocating[txg & TXG_MASK],
4299 offset, size);
4300 }
4301
4302 mutex_exit(&msp->ms_lock);
4303
4304 return (0);
4305 }
4306
4307 typedef struct metaslab_claim_cb_arg_t {
4308 uint64_t mcca_txg;
4309 int mcca_error;
4310 } metaslab_claim_cb_arg_t;
4311
4312 /* ARGSUSED */
4313 static void
4314 metaslab_claim_impl_cb(uint64_t inner_offset, vdev_t *vd, uint64_t offset,
4315 uint64_t size, void *arg)
4316 {
4317 metaslab_claim_cb_arg_t *mcca_arg = arg;
4318
4319 if (mcca_arg->mcca_error == 0) {
4320 mcca_arg->mcca_error = metaslab_claim_concrete(vd, offset,
4321 size, mcca_arg->mcca_txg);
4322 }
4323 }
4324
4325 int
4326 metaslab_claim_impl(vdev_t *vd, uint64_t offset, uint64_t size, uint64_t txg)
4327 {
4328 if (vd->vdev_ops->vdev_op_remap != NULL) {
4329 metaslab_claim_cb_arg_t arg;
4330
4331 /*
4332 * Only zdb(1M) can claim on indirect vdevs. This is used
4333 * to detect leaks of mapped space (that are not accounted
4334 * for in the obsolete counts, spacemap, or bpobj).
4335 */
4336 ASSERT(!spa_writeable(vd->vdev_spa));
4337 arg.mcca_error = 0;
4338 arg.mcca_txg = txg;
4339
4340 vd->vdev_ops->vdev_op_remap(vd, offset, size,
4341 metaslab_claim_impl_cb, &arg);
4342
4343 if (arg.mcca_error == 0) {
4344 arg.mcca_error = metaslab_claim_concrete(vd,
4345 offset, size, txg);
4346 }
4347 return (arg.mcca_error);
4348 } else {
4349 return (metaslab_claim_concrete(vd, offset, size, txg));
4350 }
4351 }
4352
4353 /*
4354 * Intent log support: upon opening the pool after a crash, notify the SPA
4355 * of blocks that the intent log has allocated for immediate write, but
4356 * which are still considered free by the SPA because the last transaction
4357 * group didn't commit yet.
4358 */
4359 static int
4360 metaslab_claim_dva(spa_t *spa, const dva_t *dva, uint64_t txg)
4361 {
4362 uint64_t vdev = DVA_GET_VDEV(dva);
4363 uint64_t offset = DVA_GET_OFFSET(dva);
4364 uint64_t size = DVA_GET_ASIZE(dva);
4365 vdev_t *vd;
4366
4367 if ((vd = vdev_lookup_top(spa, vdev)) == NULL) {
4368 return (SET_ERROR(ENXIO));
4369 }
4370
4371 ASSERT(DVA_IS_VALID(dva));
4372
4373 if (DVA_GET_GANG(dva))
4374 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
4375
4376 return (metaslab_claim_impl(vd, offset, size, txg));
4377 }
4378
4379 int
4380 metaslab_alloc(spa_t *spa, metaslab_class_t *mc, uint64_t psize, blkptr_t *bp,
4381 int ndvas, uint64_t txg, blkptr_t *hintbp, int flags,
4382 zio_alloc_list_t *zal, zio_t *zio, int allocator)
4383 {
4384 dva_t *dva = bp->blk_dva;
4385 dva_t *hintdva = (hintbp != NULL) ? hintbp->blk_dva : NULL;
4386 int error = 0;
4387
4388 ASSERT(bp->blk_birth == 0);
4389 ASSERT(BP_PHYSICAL_BIRTH(bp) == 0);
4390
4391 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
4392
4393 if (mc->mc_rotor == NULL) { /* no vdevs in this class */
4394 spa_config_exit(spa, SCL_ALLOC, FTAG);
4395 return (SET_ERROR(ENOSPC));
4396 }
4397
4398 ASSERT(ndvas > 0 && ndvas <= spa_max_replication(spa));
4399 ASSERT(BP_GET_NDVAS(bp) == 0);
4400 ASSERT(hintbp == NULL || ndvas <= BP_GET_NDVAS(hintbp));
4401 ASSERT3P(zal, !=, NULL);
4402
4403 for (int d = 0; d < ndvas; d++) {
4404 error = metaslab_alloc_dva(spa, mc, psize, dva, d, hintdva,
4405 txg, flags, zal, allocator);
4406 if (error != 0) {
4407 for (d--; d >= 0; d--) {
4408 metaslab_unalloc_dva(spa, &dva[d], txg);
4409 metaslab_group_alloc_decrement(spa,
4410 DVA_GET_VDEV(&dva[d]), zio, flags,
4411 allocator, B_FALSE);
4412 bzero(&dva[d], sizeof (dva_t));
4413 }
4414 spa_config_exit(spa, SCL_ALLOC, FTAG);
4415 return (error);
4416 } else {
4417 /*
4418 * Update the metaslab group's queue depth
4419 * based on the newly allocated dva.
4420 */
4421 metaslab_group_alloc_increment(spa,
4422 DVA_GET_VDEV(&dva[d]), zio, flags, allocator);
4423 }
4424
4425 }
4426 ASSERT(error == 0);
4427 ASSERT(BP_GET_NDVAS(bp) == ndvas);
4428
4429 spa_config_exit(spa, SCL_ALLOC, FTAG);
4430
4431 BP_SET_BIRTH(bp, txg, txg);
4432
4433 return (0);
4434 }
4435
4436 void
4437 metaslab_free(spa_t *spa, const blkptr_t *bp, uint64_t txg, boolean_t now)
4438 {
4439 const dva_t *dva = bp->blk_dva;
4440 int ndvas = BP_GET_NDVAS(bp);
4441
4442 ASSERT(!BP_IS_HOLE(bp));
4443 ASSERT(!now || bp->blk_birth >= spa_syncing_txg(spa));
4444
4445 /*
4446 * If we have a checkpoint for the pool we need to make sure that
4447 * the blocks that we free that are part of the checkpoint won't be
4448 * reused until the checkpoint is discarded or we revert to it.
4449 *
4450 * The checkpoint flag is passed down the metaslab_free code path
4451 * and is set whenever we want to add a block to the checkpoint's
4452 * accounting. That is, we "checkpoint" blocks that existed at the
4453 * time the checkpoint was created and are therefore referenced by
4454 * the checkpointed uberblock.
4455 *
4456 * Note that, we don't checkpoint any blocks if the current
4457 * syncing txg <= spa_checkpoint_txg. We want these frees to sync
4458 * normally as they will be referenced by the checkpointed uberblock.
4459 */
4460 boolean_t checkpoint = B_FALSE;
4461 if (bp->blk_birth <= spa->spa_checkpoint_txg &&
4462 spa_syncing_txg(spa) > spa->spa_checkpoint_txg) {
4463 /*
4464 * At this point, if the block is part of the checkpoint
4465 * there is no way it was created in the current txg.
4466 */
4467 ASSERT(!now);
4468 ASSERT3U(spa_syncing_txg(spa), ==, txg);
4469 checkpoint = B_TRUE;
4470 }
4471
4472 spa_config_enter(spa, SCL_FREE, FTAG, RW_READER);
4473
4474 for (int d = 0; d < ndvas; d++) {
4475 if (now) {
4476 metaslab_unalloc_dva(spa, &dva[d], txg);
4477 } else {
4478 ASSERT3U(txg, ==, spa_syncing_txg(spa));
4479 metaslab_free_dva(spa, &dva[d], checkpoint);
4480 }
4481 }
4482
4483 spa_config_exit(spa, SCL_FREE, FTAG);
4484 }
4485
4486 int
4487 metaslab_claim(spa_t *spa, const blkptr_t *bp, uint64_t txg)
4488 {
4489 const dva_t *dva = bp->blk_dva;
4490 int ndvas = BP_GET_NDVAS(bp);
4491 int error = 0;
4492
4493 ASSERT(!BP_IS_HOLE(bp));
4494
4495 if (txg != 0) {
4496 /*
4497 * First do a dry run to make sure all DVAs are claimable,
4498 * so we don't have to unwind from partial failures below.
4499 */
4500 if ((error = metaslab_claim(spa, bp, 0)) != 0)
4501 return (error);
4502 }
4503
4504 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
4505
4506 for (int d = 0; d < ndvas; d++) {
4507 error = metaslab_claim_dva(spa, &dva[d], txg);
4508 if (error != 0)
4509 break;
4510 }
4511
4512 spa_config_exit(spa, SCL_ALLOC, FTAG);
4513
4514 ASSERT(error == 0 || txg == 0);
4515
4516 return (error);
4517 }
4518
4519 /* ARGSUSED */
4520 static void
4521 metaslab_check_free_impl_cb(uint64_t inner, vdev_t *vd, uint64_t offset,
4522 uint64_t size, void *arg)
4523 {
4524 if (vd->vdev_ops == &vdev_indirect_ops)
4525 return;
4526
4527 metaslab_check_free_impl(vd, offset, size);
4528 }
4529
4530 static void
4531 metaslab_check_free_impl(vdev_t *vd, uint64_t offset, uint64_t size)
4532 {
4533 metaslab_t *msp;
4534 spa_t *spa = vd->vdev_spa;
4535
4536 if ((zfs_flags & ZFS_DEBUG_ZIO_FREE) == 0)
4537 return;
4538
4539 if (vd->vdev_ops->vdev_op_remap != NULL) {
4540 vd->vdev_ops->vdev_op_remap(vd, offset, size,
4541 metaslab_check_free_impl_cb, NULL);
4542 return;
4543 }
4544
4545 ASSERT(vdev_is_concrete(vd));
4546 ASSERT3U(offset >> vd->vdev_ms_shift, <, vd->vdev_ms_count);
4547 ASSERT3U(spa_config_held(spa, SCL_ALL, RW_READER), !=, 0);
4548
4549 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
4550
4551 mutex_enter(&msp->ms_lock);
4552 if (msp->ms_loaded) {
4553 range_tree_verify_not_present(msp->ms_allocatable,
4554 offset, size);
4555 }
4556
4557 range_tree_verify_not_present(msp->ms_freeing, offset, size);
4558 range_tree_verify_not_present(msp->ms_checkpointing, offset, size);
4559 range_tree_verify_not_present(msp->ms_freed, offset, size);
4560 for (int j = 0; j < TXG_DEFER_SIZE; j++)
4561 range_tree_verify_not_present(msp->ms_defer[j], offset, size);
4562 mutex_exit(&msp->ms_lock);
4563 }
4564
4565 void
4566 metaslab_check_free(spa_t *spa, const blkptr_t *bp)
4567 {
4568 if ((zfs_flags & ZFS_DEBUG_ZIO_FREE) == 0)
4569 return;
4570
4571 spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
4572 for (int i = 0; i < BP_GET_NDVAS(bp); i++) {
4573 uint64_t vdev = DVA_GET_VDEV(&bp->blk_dva[i]);
4574 vdev_t *vd = vdev_lookup_top(spa, vdev);
4575 uint64_t offset = DVA_GET_OFFSET(&bp->blk_dva[i]);
4576 uint64_t size = DVA_GET_ASIZE(&bp->blk_dva[i]);
4577
4578 if (DVA_GET_GANG(&bp->blk_dva[i]))
4579 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
4580
4581 ASSERT3P(vd, !=, NULL);
4582
4583 metaslab_check_free_impl(vd, offset, size);
4584 }
4585 spa_config_exit(spa, SCL_VDEV, FTAG);
4586 }