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