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 */
24
25 #include <sys/zfs_context.h>
26 #include <sys/dmu.h>
27 #include <sys/dmu_tx.h>
28 #include <sys/space_map.h>
29 #include <sys/metaslab_impl.h>
30 #include <sys/vdev_impl.h>
31 #include <sys/zio.h>
32
33 uint64_t metaslab_aliquot = 512ULL << 10;
34 uint64_t metaslab_gang_bang = SPA_MAXBLOCKSIZE + 1; /* force gang blocks */
35
36 /*
37 * Metaslab debugging: when set, keeps all space maps in core to verify frees.
38 */
39 static int metaslab_debug = 0;
40
41 /*
42 * Minimum size which forces the dynamic allocator to change
43 * it's allocation strategy. Once the space map cannot satisfy
44 * an allocation of this size then it switches to using more
45 * aggressive strategy (i.e search by size rather than offset).
46 */
47 uint64_t metaslab_df_alloc_threshold = SPA_MAXBLOCKSIZE;
48
49 /*
50 * The minimum free space, in percent, which must be available
51 * in a space map to continue allocations in a first-fit fashion.
52 * Once the space_map's free space drops below this level we dynamically
53 * switch to using best-fit allocations.
54 */
55 int metaslab_df_free_pct = 4;
56
57 /*
58 * A metaslab is considered "free" if it contains a contiguous
59 * segment which is greater than metaslab_min_alloc_size.
60 */
61 uint64_t metaslab_min_alloc_size = DMU_MAX_ACCESS;
62
63 /*
64 * Max number of space_maps to prefetch.
65 */
66 int metaslab_prefetch_limit = SPA_DVAS_PER_BP;
67
68 /*
69 * Percentage bonus multiplier for metaslabs that are in the bonus area.
70 */
71 int metaslab_smo_bonus_pct = 150;
72
73 /*
74 * ==========================================================================
75 * Metaslab classes
76 * ==========================================================================
77 */
78 metaslab_class_t *
metaslab_class_create(spa_t * spa,space_map_ops_t * ops)79 metaslab_class_create(spa_t *spa, space_map_ops_t *ops)
80 {
81 metaslab_class_t *mc;
82
83 mc = kmem_zalloc(sizeof (metaslab_class_t), KM_SLEEP);
84
85 mc->mc_spa = spa;
86 mc->mc_rotor = NULL;
87 mc->mc_ops = ops;
88
89 return (mc);
90 }
91
92 void
metaslab_class_destroy(metaslab_class_t * mc)93 metaslab_class_destroy(metaslab_class_t *mc)
94 {
95 ASSERT(mc->mc_rotor == NULL);
96 ASSERT(mc->mc_alloc == 0);
97 ASSERT(mc->mc_deferred == 0);
98 ASSERT(mc->mc_space == 0);
99 ASSERT(mc->mc_dspace == 0);
100
101 kmem_free(mc, sizeof (metaslab_class_t));
102 }
103
104 int
metaslab_class_validate(metaslab_class_t * mc)105 metaslab_class_validate(metaslab_class_t *mc)
106 {
107 metaslab_group_t *mg;
108 vdev_t *vd;
109
110 /*
111 * Must hold one of the spa_config locks.
112 */
113 ASSERT(spa_config_held(mc->mc_spa, SCL_ALL, RW_READER) ||
114 spa_config_held(mc->mc_spa, SCL_ALL, RW_WRITER));
115
116 if ((mg = mc->mc_rotor) == NULL)
117 return (0);
118
119 do {
120 vd = mg->mg_vd;
121 ASSERT(vd->vdev_mg != NULL);
122 ASSERT3P(vd->vdev_top, ==, vd);
123 ASSERT3P(mg->mg_class, ==, mc);
124 ASSERT3P(vd->vdev_ops, !=, &vdev_hole_ops);
125 } while ((mg = mg->mg_next) != mc->mc_rotor);
126
127 return (0);
128 }
129
130 void
metaslab_class_space_update(metaslab_class_t * mc,int64_t alloc_delta,int64_t defer_delta,int64_t space_delta,int64_t dspace_delta)131 metaslab_class_space_update(metaslab_class_t *mc, int64_t alloc_delta,
132 int64_t defer_delta, int64_t space_delta, int64_t dspace_delta)
133 {
134 atomic_add_64(&mc->mc_alloc, alloc_delta);
135 atomic_add_64(&mc->mc_deferred, defer_delta);
136 atomic_add_64(&mc->mc_space, space_delta);
137 atomic_add_64(&mc->mc_dspace, dspace_delta);
138 }
139
140 uint64_t
metaslab_class_get_alloc(metaslab_class_t * mc)141 metaslab_class_get_alloc(metaslab_class_t *mc)
142 {
143 return (mc->mc_alloc);
144 }
145
146 uint64_t
metaslab_class_get_deferred(metaslab_class_t * mc)147 metaslab_class_get_deferred(metaslab_class_t *mc)
148 {
149 return (mc->mc_deferred);
150 }
151
152 uint64_t
metaslab_class_get_space(metaslab_class_t * mc)153 metaslab_class_get_space(metaslab_class_t *mc)
154 {
155 return (mc->mc_space);
156 }
157
158 uint64_t
metaslab_class_get_dspace(metaslab_class_t * mc)159 metaslab_class_get_dspace(metaslab_class_t *mc)
160 {
161 return (spa_deflate(mc->mc_spa) ? mc->mc_dspace : mc->mc_space);
162 }
163
164 /*
165 * ==========================================================================
166 * Metaslab groups
167 * ==========================================================================
168 */
169 static int
metaslab_compare(const void * x1,const void * x2)170 metaslab_compare(const void *x1, const void *x2)
171 {
172 const metaslab_t *m1 = x1;
173 const metaslab_t *m2 = x2;
174
175 if (m1->ms_weight < m2->ms_weight)
176 return (1);
177 if (m1->ms_weight > m2->ms_weight)
178 return (-1);
179
180 /*
181 * If the weights are identical, use the offset to force uniqueness.
182 */
183 if (m1->ms_map.sm_start < m2->ms_map.sm_start)
184 return (-1);
185 if (m1->ms_map.sm_start > m2->ms_map.sm_start)
186 return (1);
187
188 ASSERT3P(m1, ==, m2);
189
190 return (0);
191 }
192
193 metaslab_group_t *
metaslab_group_create(metaslab_class_t * mc,vdev_t * vd)194 metaslab_group_create(metaslab_class_t *mc, vdev_t *vd)
195 {
196 metaslab_group_t *mg;
197
198 mg = kmem_zalloc(sizeof (metaslab_group_t), KM_SLEEP);
199 mutex_init(&mg->mg_lock, NULL, MUTEX_DEFAULT, NULL);
200 avl_create(&mg->mg_metaslab_tree, metaslab_compare,
201 sizeof (metaslab_t), offsetof(struct metaslab, ms_group_node));
202 mg->mg_vd = vd;
203 mg->mg_class = mc;
204 mg->mg_activation_count = 0;
205
206 return (mg);
207 }
208
209 void
metaslab_group_destroy(metaslab_group_t * mg)210 metaslab_group_destroy(metaslab_group_t *mg)
211 {
212 ASSERT(mg->mg_prev == NULL);
213 ASSERT(mg->mg_next == NULL);
214 /*
215 * We may have gone below zero with the activation count
216 * either because we never activated in the first place or
217 * because we're done, and possibly removing the vdev.
218 */
219 ASSERT(mg->mg_activation_count <= 0);
220
221 avl_destroy(&mg->mg_metaslab_tree);
222 mutex_destroy(&mg->mg_lock);
223 kmem_free(mg, sizeof (metaslab_group_t));
224 }
225
226 void
metaslab_group_activate(metaslab_group_t * mg)227 metaslab_group_activate(metaslab_group_t *mg)
228 {
229 metaslab_class_t *mc = mg->mg_class;
230 metaslab_group_t *mgprev, *mgnext;
231
232 ASSERT(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_WRITER));
233
234 ASSERT(mc->mc_rotor != mg);
235 ASSERT(mg->mg_prev == NULL);
236 ASSERT(mg->mg_next == NULL);
237 ASSERT(mg->mg_activation_count <= 0);
238
239 if (++mg->mg_activation_count <= 0)
240 return;
241
242 mg->mg_aliquot = metaslab_aliquot * MAX(1, mg->mg_vd->vdev_children);
243
244 if ((mgprev = mc->mc_rotor) == NULL) {
245 mg->mg_prev = mg;
246 mg->mg_next = mg;
247 } else {
248 mgnext = mgprev->mg_next;
249 mg->mg_prev = mgprev;
250 mg->mg_next = mgnext;
251 mgprev->mg_next = mg;
252 mgnext->mg_prev = mg;
253 }
254 mc->mc_rotor = mg;
255 }
256
257 void
metaslab_group_passivate(metaslab_group_t * mg)258 metaslab_group_passivate(metaslab_group_t *mg)
259 {
260 metaslab_class_t *mc = mg->mg_class;
261 metaslab_group_t *mgprev, *mgnext;
262
263 ASSERT(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_WRITER));
264
265 if (--mg->mg_activation_count != 0) {
266 ASSERT(mc->mc_rotor != mg);
267 ASSERT(mg->mg_prev == NULL);
268 ASSERT(mg->mg_next == NULL);
269 ASSERT(mg->mg_activation_count < 0);
270 return;
271 }
272
273 mgprev = mg->mg_prev;
274 mgnext = mg->mg_next;
275
276 if (mg == mgnext) {
277 mc->mc_rotor = NULL;
278 } else {
279 mc->mc_rotor = mgnext;
280 mgprev->mg_next = mgnext;
281 mgnext->mg_prev = mgprev;
282 }
283
284 mg->mg_prev = NULL;
285 mg->mg_next = NULL;
286 }
287
288 static void
metaslab_group_add(metaslab_group_t * mg,metaslab_t * msp)289 metaslab_group_add(metaslab_group_t *mg, metaslab_t *msp)
290 {
291 mutex_enter(&mg->mg_lock);
292 ASSERT(msp->ms_group == NULL);
293 msp->ms_group = mg;
294 msp->ms_weight = 0;
295 avl_add(&mg->mg_metaslab_tree, msp);
296 mutex_exit(&mg->mg_lock);
297 }
298
299 static void
metaslab_group_remove(metaslab_group_t * mg,metaslab_t * msp)300 metaslab_group_remove(metaslab_group_t *mg, metaslab_t *msp)
301 {
302 mutex_enter(&mg->mg_lock);
303 ASSERT(msp->ms_group == mg);
304 avl_remove(&mg->mg_metaslab_tree, msp);
305 msp->ms_group = NULL;
306 mutex_exit(&mg->mg_lock);
307 }
308
309 static void
metaslab_group_sort(metaslab_group_t * mg,metaslab_t * msp,uint64_t weight)310 metaslab_group_sort(metaslab_group_t *mg, metaslab_t *msp, uint64_t weight)
311 {
312 /*
313 * Although in principle the weight can be any value, in
314 * practice we do not use values in the range [1, 510].
315 */
316 ASSERT(weight >= SPA_MINBLOCKSIZE-1 || weight == 0);
317 ASSERT(MUTEX_HELD(&msp->ms_lock));
318
319 mutex_enter(&mg->mg_lock);
320 ASSERT(msp->ms_group == mg);
321 avl_remove(&mg->mg_metaslab_tree, msp);
322 msp->ms_weight = weight;
323 avl_add(&mg->mg_metaslab_tree, msp);
324 mutex_exit(&mg->mg_lock);
325 }
326
327 /*
328 * ==========================================================================
329 * Common allocator routines
330 * ==========================================================================
331 */
332 static int
metaslab_segsize_compare(const void * x1,const void * x2)333 metaslab_segsize_compare(const void *x1, const void *x2)
334 {
335 const space_seg_t *s1 = x1;
336 const space_seg_t *s2 = x2;
337 uint64_t ss_size1 = s1->ss_end - s1->ss_start;
338 uint64_t ss_size2 = s2->ss_end - s2->ss_start;
339
340 if (ss_size1 < ss_size2)
341 return (-1);
342 if (ss_size1 > ss_size2)
343 return (1);
344
345 if (s1->ss_start < s2->ss_start)
346 return (-1);
347 if (s1->ss_start > s2->ss_start)
348 return (1);
349
350 return (0);
351 }
352
353 /*
354 * This is a helper function that can be used by the allocator to find
355 * a suitable block to allocate. This will search the specified AVL
356 * tree looking for a block that matches the specified criteria.
357 */
358 static uint64_t
metaslab_block_picker(avl_tree_t * t,uint64_t * cursor,uint64_t size,uint64_t align)359 metaslab_block_picker(avl_tree_t *t, uint64_t *cursor, uint64_t size,
360 uint64_t align)
361 {
362 space_seg_t *ss, ssearch;
363 avl_index_t where;
364
365 ssearch.ss_start = *cursor;
366 ssearch.ss_end = *cursor + size;
367
368 ss = avl_find(t, &ssearch, &where);
369 if (ss == NULL)
370 ss = avl_nearest(t, where, AVL_AFTER);
371
372 while (ss != NULL) {
373 uint64_t offset = P2ROUNDUP(ss->ss_start, align);
374
375 if (offset + size <= ss->ss_end) {
376 *cursor = offset + size;
377 return (offset);
378 }
379 ss = AVL_NEXT(t, ss);
380 }
381
382 /*
383 * If we know we've searched the whole map (*cursor == 0), give up.
384 * Otherwise, reset the cursor to the beginning and try again.
385 */
386 if (*cursor == 0)
387 return (-1ULL);
388
389 *cursor = 0;
390 return (metaslab_block_picker(t, cursor, size, align));
391 }
392
393 static void
metaslab_pp_load(space_map_t * sm)394 metaslab_pp_load(space_map_t *sm)
395 {
396 space_seg_t *ss;
397
398 ASSERT(sm->sm_ppd == NULL);
399 sm->sm_ppd = kmem_zalloc(64 * sizeof (uint64_t), KM_SLEEP);
400
401 sm->sm_pp_root = kmem_alloc(sizeof (avl_tree_t), KM_SLEEP);
402 avl_create(sm->sm_pp_root, metaslab_segsize_compare,
403 sizeof (space_seg_t), offsetof(struct space_seg, ss_pp_node));
404
405 for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss))
406 avl_add(sm->sm_pp_root, ss);
407 }
408
409 static void
metaslab_pp_unload(space_map_t * sm)410 metaslab_pp_unload(space_map_t *sm)
411 {
412 void *cookie = NULL;
413
414 kmem_free(sm->sm_ppd, 64 * sizeof (uint64_t));
415 sm->sm_ppd = NULL;
416
417 while (avl_destroy_nodes(sm->sm_pp_root, &cookie) != NULL) {
418 /* tear down the tree */
419 }
420
421 avl_destroy(sm->sm_pp_root);
422 kmem_free(sm->sm_pp_root, sizeof (avl_tree_t));
423 sm->sm_pp_root = NULL;
424 }
425
426 /* ARGSUSED */
427 static void
metaslab_pp_claim(space_map_t * sm,uint64_t start,uint64_t size)428 metaslab_pp_claim(space_map_t *sm, uint64_t start, uint64_t size)
429 {
430 /* No need to update cursor */
431 }
432
433 /* ARGSUSED */
434 static void
metaslab_pp_free(space_map_t * sm,uint64_t start,uint64_t size)435 metaslab_pp_free(space_map_t *sm, uint64_t start, uint64_t size)
436 {
437 /* No need to update cursor */
438 }
439
440 /*
441 * Return the maximum contiguous segment within the metaslab.
442 */
443 uint64_t
metaslab_pp_maxsize(space_map_t * sm)444 metaslab_pp_maxsize(space_map_t *sm)
445 {
446 avl_tree_t *t = sm->sm_pp_root;
447 space_seg_t *ss;
448
449 if (t == NULL || (ss = avl_last(t)) == NULL)
450 return (0ULL);
451
452 return (ss->ss_end - ss->ss_start);
453 }
454
455 /*
456 * ==========================================================================
457 * The first-fit block allocator
458 * ==========================================================================
459 */
460 static uint64_t
metaslab_ff_alloc(space_map_t * sm,uint64_t size)461 metaslab_ff_alloc(space_map_t *sm, uint64_t size)
462 {
463 avl_tree_t *t = &sm->sm_root;
464 uint64_t align = size & -size;
465 uint64_t *cursor = (uint64_t *)sm->sm_ppd + highbit(align) - 1;
466
467 return (metaslab_block_picker(t, cursor, size, align));
468 }
469
470 /* ARGSUSED */
471 boolean_t
metaslab_ff_fragmented(space_map_t * sm)472 metaslab_ff_fragmented(space_map_t *sm)
473 {
474 return (B_TRUE);
475 }
476
477 static space_map_ops_t metaslab_ff_ops = {
478 metaslab_pp_load,
479 metaslab_pp_unload,
480 metaslab_ff_alloc,
481 metaslab_pp_claim,
482 metaslab_pp_free,
483 metaslab_pp_maxsize,
484 metaslab_ff_fragmented
485 };
486
487 /*
488 * ==========================================================================
489 * Dynamic block allocator -
490 * Uses the first fit allocation scheme until space get low and then
491 * adjusts to a best fit allocation method. Uses metaslab_df_alloc_threshold
492 * and metaslab_df_free_pct to determine when to switch the allocation scheme.
493 * ==========================================================================
494 */
495 static uint64_t
metaslab_df_alloc(space_map_t * sm,uint64_t size)496 metaslab_df_alloc(space_map_t *sm, uint64_t size)
497 {
498 avl_tree_t *t = &sm->sm_root;
499 uint64_t align = size & -size;
500 uint64_t *cursor = (uint64_t *)sm->sm_ppd + highbit(align) - 1;
501 uint64_t max_size = metaslab_pp_maxsize(sm);
502 int free_pct = sm->sm_space * 100 / sm->sm_size;
503
504 ASSERT(MUTEX_HELD(sm->sm_lock));
505 ASSERT3U(avl_numnodes(&sm->sm_root), ==, avl_numnodes(sm->sm_pp_root));
506
507 if (max_size < size)
508 return (-1ULL);
509
510 /*
511 * If we're running low on space switch to using the size
512 * sorted AVL tree (best-fit).
513 */
514 if (max_size < metaslab_df_alloc_threshold ||
515 free_pct < metaslab_df_free_pct) {
516 t = sm->sm_pp_root;
517 *cursor = 0;
518 }
519
520 return (metaslab_block_picker(t, cursor, size, 1ULL));
521 }
522
523 static boolean_t
metaslab_df_fragmented(space_map_t * sm)524 metaslab_df_fragmented(space_map_t *sm)
525 {
526 uint64_t max_size = metaslab_pp_maxsize(sm);
527 int free_pct = sm->sm_space * 100 / sm->sm_size;
528
529 if (max_size >= metaslab_df_alloc_threshold &&
530 free_pct >= metaslab_df_free_pct)
531 return (B_FALSE);
532
533 return (B_TRUE);
534 }
535
536 static space_map_ops_t metaslab_df_ops = {
537 metaslab_pp_load,
538 metaslab_pp_unload,
539 metaslab_df_alloc,
540 metaslab_pp_claim,
541 metaslab_pp_free,
542 metaslab_pp_maxsize,
543 metaslab_df_fragmented
544 };
545
546 /*
547 * ==========================================================================
548 * Other experimental allocators
549 * ==========================================================================
550 */
551 static uint64_t
metaslab_cdf_alloc(space_map_t * sm,uint64_t size)552 metaslab_cdf_alloc(space_map_t *sm, uint64_t size)
553 {
554 avl_tree_t *t = &sm->sm_root;
555 uint64_t *cursor = (uint64_t *)sm->sm_ppd;
556 uint64_t *extent_end = (uint64_t *)sm->sm_ppd + 1;
557 uint64_t max_size = metaslab_pp_maxsize(sm);
558 uint64_t rsize = size;
559 uint64_t offset = 0;
560
561 ASSERT(MUTEX_HELD(sm->sm_lock));
562 ASSERT3U(avl_numnodes(&sm->sm_root), ==, avl_numnodes(sm->sm_pp_root));
563
564 if (max_size < size)
565 return (-1ULL);
566
567 ASSERT3U(*extent_end, >=, *cursor);
568
569 /*
570 * If we're running low on space switch to using the size
571 * sorted AVL tree (best-fit).
572 */
573 if ((*cursor + size) > *extent_end) {
574
575 t = sm->sm_pp_root;
576 *cursor = *extent_end = 0;
577
578 if (max_size > 2 * SPA_MAXBLOCKSIZE)
579 rsize = MIN(metaslab_min_alloc_size, max_size);
580 offset = metaslab_block_picker(t, extent_end, rsize, 1ULL);
581 if (offset != -1)
582 *cursor = offset + size;
583 } else {
584 offset = metaslab_block_picker(t, cursor, rsize, 1ULL);
585 }
586 ASSERT3U(*cursor, <=, *extent_end);
587 return (offset);
588 }
589
590 static boolean_t
metaslab_cdf_fragmented(space_map_t * sm)591 metaslab_cdf_fragmented(space_map_t *sm)
592 {
593 uint64_t max_size = metaslab_pp_maxsize(sm);
594
595 if (max_size > (metaslab_min_alloc_size * 10))
596 return (B_FALSE);
597 return (B_TRUE);
598 }
599
600 static space_map_ops_t metaslab_cdf_ops = {
601 metaslab_pp_load,
602 metaslab_pp_unload,
603 metaslab_cdf_alloc,
604 metaslab_pp_claim,
605 metaslab_pp_free,
606 metaslab_pp_maxsize,
607 metaslab_cdf_fragmented
608 };
609
610 uint64_t metaslab_ndf_clump_shift = 4;
611
612 static uint64_t
metaslab_ndf_alloc(space_map_t * sm,uint64_t size)613 metaslab_ndf_alloc(space_map_t *sm, uint64_t size)
614 {
615 avl_tree_t *t = &sm->sm_root;
616 avl_index_t where;
617 space_seg_t *ss, ssearch;
618 uint64_t hbit = highbit(size);
619 uint64_t *cursor = (uint64_t *)sm->sm_ppd + hbit - 1;
620 uint64_t max_size = metaslab_pp_maxsize(sm);
621
622 ASSERT(MUTEX_HELD(sm->sm_lock));
623 ASSERT3U(avl_numnodes(&sm->sm_root), ==, avl_numnodes(sm->sm_pp_root));
624
625 if (max_size < size)
626 return (-1ULL);
627
628 ssearch.ss_start = *cursor;
629 ssearch.ss_end = *cursor + size;
630
631 ss = avl_find(t, &ssearch, &where);
632 if (ss == NULL || (ss->ss_start + size > ss->ss_end)) {
633 t = sm->sm_pp_root;
634
635 ssearch.ss_start = 0;
636 ssearch.ss_end = MIN(max_size,
637 1ULL << (hbit + metaslab_ndf_clump_shift));
638 ss = avl_find(t, &ssearch, &where);
639 if (ss == NULL)
640 ss = avl_nearest(t, where, AVL_AFTER);
641 ASSERT(ss != NULL);
642 }
643
644 if (ss != NULL) {
645 if (ss->ss_start + size <= ss->ss_end) {
646 *cursor = ss->ss_start + size;
647 return (ss->ss_start);
648 }
649 }
650 return (-1ULL);
651 }
652
653 static boolean_t
metaslab_ndf_fragmented(space_map_t * sm)654 metaslab_ndf_fragmented(space_map_t *sm)
655 {
656 uint64_t max_size = metaslab_pp_maxsize(sm);
657
658 if (max_size > (metaslab_min_alloc_size << metaslab_ndf_clump_shift))
659 return (B_FALSE);
660 return (B_TRUE);
661 }
662
663
664 static space_map_ops_t metaslab_ndf_ops = {
665 metaslab_pp_load,
666 metaslab_pp_unload,
667 metaslab_ndf_alloc,
668 metaslab_pp_claim,
669 metaslab_pp_free,
670 metaslab_pp_maxsize,
671 metaslab_ndf_fragmented
672 };
673
674 space_map_ops_t *zfs_metaslab_ops = &metaslab_ndf_ops;
675
676 /*
677 * ==========================================================================
678 * Metaslabs
679 * ==========================================================================
680 */
681 metaslab_t *
metaslab_init(metaslab_group_t * mg,space_map_obj_t * smo,uint64_t start,uint64_t size,uint64_t txg)682 metaslab_init(metaslab_group_t *mg, space_map_obj_t *smo,
683 uint64_t start, uint64_t size, uint64_t txg)
684 {
685 vdev_t *vd = mg->mg_vd;
686 metaslab_t *msp;
687
688 msp = kmem_zalloc(sizeof (metaslab_t), KM_SLEEP);
689 mutex_init(&msp->ms_lock, NULL, MUTEX_DEFAULT, NULL);
690
691 msp->ms_smo_syncing = *smo;
692
693 /*
694 * We create the main space map here, but we don't create the
695 * allocmaps and freemaps until metaslab_sync_done(). This serves
696 * two purposes: it allows metaslab_sync_done() to detect the
697 * addition of new space; and for debugging, it ensures that we'd
698 * data fault on any attempt to use this metaslab before it's ready.
699 */
700 space_map_create(&msp->ms_map, start, size,
701 vd->vdev_ashift, &msp->ms_lock);
702
703 metaslab_group_add(mg, msp);
704
705 if (metaslab_debug && smo->smo_object != 0) {
706 mutex_enter(&msp->ms_lock);
707 VERIFY(space_map_load(&msp->ms_map, mg->mg_class->mc_ops,
708 SM_FREE, smo, spa_meta_objset(vd->vdev_spa)) == 0);
709 mutex_exit(&msp->ms_lock);
710 }
711
712 /*
713 * If we're opening an existing pool (txg == 0) or creating
714 * a new one (txg == TXG_INITIAL), all space is available now.
715 * If we're adding space to an existing pool, the new space
716 * does not become available until after this txg has synced.
717 */
718 if (txg <= TXG_INITIAL)
719 metaslab_sync_done(msp, 0);
720
721 if (txg != 0) {
722 vdev_dirty(vd, 0, NULL, txg);
723 vdev_dirty(vd, VDD_METASLAB, msp, txg);
724 }
725
726 return (msp);
727 }
728
729 void
metaslab_fini(metaslab_t * msp)730 metaslab_fini(metaslab_t *msp)
731 {
732 metaslab_group_t *mg = msp->ms_group;
733
734 vdev_space_update(mg->mg_vd,
735 -msp->ms_smo.smo_alloc, 0, -msp->ms_map.sm_size);
736
737 metaslab_group_remove(mg, msp);
738
739 mutex_enter(&msp->ms_lock);
740
741 space_map_unload(&msp->ms_map);
742 space_map_destroy(&msp->ms_map);
743
744 for (int t = 0; t < TXG_SIZE; t++) {
745 space_map_destroy(&msp->ms_allocmap[t]);
746 space_map_destroy(&msp->ms_freemap[t]);
747 }
748
749 for (int t = 0; t < TXG_DEFER_SIZE; t++)
750 space_map_destroy(&msp->ms_defermap[t]);
751
752 ASSERT3S(msp->ms_deferspace, ==, 0);
753
754 mutex_exit(&msp->ms_lock);
755 mutex_destroy(&msp->ms_lock);
756
757 kmem_free(msp, sizeof (metaslab_t));
758 }
759
760 #define METASLAB_WEIGHT_PRIMARY (1ULL << 63)
761 #define METASLAB_WEIGHT_SECONDARY (1ULL << 62)
762 #define METASLAB_ACTIVE_MASK \
763 (METASLAB_WEIGHT_PRIMARY | METASLAB_WEIGHT_SECONDARY)
764
765 static uint64_t
metaslab_weight(metaslab_t * msp)766 metaslab_weight(metaslab_t *msp)
767 {
768 metaslab_group_t *mg = msp->ms_group;
769 space_map_t *sm = &msp->ms_map;
770 space_map_obj_t *smo = &msp->ms_smo;
771 vdev_t *vd = mg->mg_vd;
772 uint64_t weight, space;
773
774 ASSERT(MUTEX_HELD(&msp->ms_lock));
775
776 /*
777 * The baseline weight is the metaslab's free space.
778 */
779 space = sm->sm_size - smo->smo_alloc;
780 weight = space;
781
782 /*
783 * Modern disks have uniform bit density and constant angular velocity.
784 * Therefore, the outer recording zones are faster (higher bandwidth)
785 * than the inner zones by the ratio of outer to inner track diameter,
786 * which is typically around 2:1. We account for this by assigning
787 * higher weight to lower metaslabs (multiplier ranging from 2x to 1x).
788 * In effect, this means that we'll select the metaslab with the most
789 * free bandwidth rather than simply the one with the most free space.
790 */
791 weight = 2 * weight -
792 ((sm->sm_start >> vd->vdev_ms_shift) * weight) / vd->vdev_ms_count;
793 ASSERT(weight >= space && weight <= 2 * space);
794
795 /*
796 * For locality, assign higher weight to metaslabs which have
797 * a lower offset than what we've already activated.
798 */
799 if (sm->sm_start <= mg->mg_bonus_area)
800 weight *= (metaslab_smo_bonus_pct / 100);
801 ASSERT(weight >= space &&
802 weight <= 2 * (metaslab_smo_bonus_pct / 100) * space);
803
804 if (sm->sm_loaded && !sm->sm_ops->smop_fragmented(sm)) {
805 /*
806 * If this metaslab is one we're actively using, adjust its
807 * weight to make it preferable to any inactive metaslab so
808 * we'll polish it off.
809 */
810 weight |= (msp->ms_weight & METASLAB_ACTIVE_MASK);
811 }
812 return (weight);
813 }
814
815 static void
metaslab_prefetch(metaslab_group_t * mg)816 metaslab_prefetch(metaslab_group_t *mg)
817 {
818 spa_t *spa = mg->mg_vd->vdev_spa;
819 metaslab_t *msp;
820 avl_tree_t *t = &mg->mg_metaslab_tree;
821 int m;
822
823 mutex_enter(&mg->mg_lock);
824
825 /*
826 * Prefetch the next potential metaslabs
827 */
828 for (msp = avl_first(t), m = 0; msp; msp = AVL_NEXT(t, msp), m++) {
829 space_map_t *sm = &msp->ms_map;
830 space_map_obj_t *smo = &msp->ms_smo;
831
832 /* If we have reached our prefetch limit then we're done */
833 if (m >= metaslab_prefetch_limit)
834 break;
835
836 if (!sm->sm_loaded && smo->smo_object != 0) {
837 mutex_exit(&mg->mg_lock);
838 dmu_prefetch(spa_meta_objset(spa), smo->smo_object,
839 0ULL, smo->smo_objsize);
840 mutex_enter(&mg->mg_lock);
841 }
842 }
843 mutex_exit(&mg->mg_lock);
844 }
845
846 static int
metaslab_activate(metaslab_t * msp,uint64_t activation_weight,uint64_t size)847 metaslab_activate(metaslab_t *msp, uint64_t activation_weight, uint64_t size)
848 {
849 metaslab_group_t *mg = msp->ms_group;
850 space_map_t *sm = &msp->ms_map;
851 space_map_ops_t *sm_ops = msp->ms_group->mg_class->mc_ops;
852
853 ASSERT(MUTEX_HELD(&msp->ms_lock));
854
855 if ((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
856 space_map_load_wait(sm);
857 if (!sm->sm_loaded) {
858 int error = space_map_load(sm, sm_ops, SM_FREE,
859 &msp->ms_smo,
860 spa_meta_objset(msp->ms_group->mg_vd->vdev_spa));
861 if (error) {
862 metaslab_group_sort(msp->ms_group, msp, 0);
863 return (error);
864 }
865 for (int t = 0; t < TXG_DEFER_SIZE; t++)
866 space_map_walk(&msp->ms_defermap[t],
867 space_map_claim, sm);
868
869 }
870
871 /*
872 * Track the bonus area as we activate new metaslabs.
873 */
874 if (sm->sm_start > mg->mg_bonus_area) {
875 mutex_enter(&mg->mg_lock);
876 mg->mg_bonus_area = sm->sm_start;
877 mutex_exit(&mg->mg_lock);
878 }
879
880 /*
881 * If we were able to load the map then make sure
882 * that this map is still able to satisfy our request.
883 */
884 if (msp->ms_weight < size)
885 return (ENOSPC);
886
887 metaslab_group_sort(msp->ms_group, msp,
888 msp->ms_weight | activation_weight);
889 }
890 ASSERT(sm->sm_loaded);
891 ASSERT(msp->ms_weight & METASLAB_ACTIVE_MASK);
892
893 return (0);
894 }
895
896 static void
metaslab_passivate(metaslab_t * msp,uint64_t size)897 metaslab_passivate(metaslab_t *msp, uint64_t size)
898 {
899 /*
900 * If size < SPA_MINBLOCKSIZE, then we will not allocate from
901 * this metaslab again. In that case, it had better be empty,
902 * or we would be leaving space on the table.
903 */
904 ASSERT(size >= SPA_MINBLOCKSIZE || msp->ms_map.sm_space == 0);
905 metaslab_group_sort(msp->ms_group, msp, MIN(msp->ms_weight, size));
906 ASSERT((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0);
907 }
908
909 /*
910 * Write a metaslab to disk in the context of the specified transaction group.
911 */
912 void
metaslab_sync(metaslab_t * msp,uint64_t txg)913 metaslab_sync(metaslab_t *msp, uint64_t txg)
914 {
915 vdev_t *vd = msp->ms_group->mg_vd;
916 spa_t *spa = vd->vdev_spa;
917 objset_t *mos = spa_meta_objset(spa);
918 space_map_t *allocmap = &msp->ms_allocmap[txg & TXG_MASK];
919 space_map_t *freemap = &msp->ms_freemap[txg & TXG_MASK];
920 space_map_t *freed_map = &msp->ms_freemap[TXG_CLEAN(txg) & TXG_MASK];
921 space_map_t *sm = &msp->ms_map;
922 space_map_obj_t *smo = &msp->ms_smo_syncing;
923 dmu_buf_t *db;
924 dmu_tx_t *tx;
925
926 ASSERT(!vd->vdev_ishole);
927
928 if (allocmap->sm_space == 0 && freemap->sm_space == 0)
929 return;
930
931 /*
932 * The only state that can actually be changing concurrently with
933 * metaslab_sync() is the metaslab's ms_map. No other thread can
934 * be modifying this txg's allocmap, freemap, freed_map, or smo.
935 * Therefore, we only hold ms_lock to satify space_map ASSERTs.
936 * We drop it whenever we call into the DMU, because the DMU
937 * can call down to us (e.g. via zio_free()) at any time.
938 */
939
940 tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
941
942 if (smo->smo_object == 0) {
943 ASSERT(smo->smo_objsize == 0);
944 ASSERT(smo->smo_alloc == 0);
945 smo->smo_object = dmu_object_alloc(mos,
946 DMU_OT_SPACE_MAP, 1 << SPACE_MAP_BLOCKSHIFT,
947 DMU_OT_SPACE_MAP_HEADER, sizeof (*smo), tx);
948 ASSERT(smo->smo_object != 0);
949 dmu_write(mos, vd->vdev_ms_array, sizeof (uint64_t) *
950 (sm->sm_start >> vd->vdev_ms_shift),
951 sizeof (uint64_t), &smo->smo_object, tx);
952 }
953
954 mutex_enter(&msp->ms_lock);
955
956 space_map_walk(freemap, space_map_add, freed_map);
957
958 if (sm->sm_loaded && spa_sync_pass(spa) == 1 && smo->smo_objsize >=
959 2 * sizeof (uint64_t) * avl_numnodes(&sm->sm_root)) {
960 /*
961 * The in-core space map representation is twice as compact
962 * as the on-disk one, so it's time to condense the latter
963 * by generating a pure allocmap from first principles.
964 *
965 * This metaslab is 100% allocated,
966 * minus the content of the in-core map (sm),
967 * minus what's been freed this txg (freed_map),
968 * minus deferred frees (ms_defermap[]),
969 * minus allocations from txgs in the future
970 * (because they haven't been committed yet).
971 */
972 space_map_vacate(allocmap, NULL, NULL);
973 space_map_vacate(freemap, NULL, NULL);
974
975 space_map_add(allocmap, allocmap->sm_start, allocmap->sm_size);
976
977 space_map_walk(sm, space_map_remove, allocmap);
978 space_map_walk(freed_map, space_map_remove, allocmap);
979
980 for (int t = 0; t < TXG_DEFER_SIZE; t++)
981 space_map_walk(&msp->ms_defermap[t],
982 space_map_remove, allocmap);
983
984 for (int t = 1; t < TXG_CONCURRENT_STATES; t++)
985 space_map_walk(&msp->ms_allocmap[(txg + t) & TXG_MASK],
986 space_map_remove, allocmap);
987
988 mutex_exit(&msp->ms_lock);
989 space_map_truncate(smo, mos, tx);
990 mutex_enter(&msp->ms_lock);
991 }
992
993 space_map_sync(allocmap, SM_ALLOC, smo, mos, tx);
994 space_map_sync(freemap, SM_FREE, smo, mos, tx);
995
996 mutex_exit(&msp->ms_lock);
997
998 VERIFY(0 == dmu_bonus_hold(mos, smo->smo_object, FTAG, &db));
999 dmu_buf_will_dirty(db, tx);
1000 ASSERT3U(db->db_size, >=, sizeof (*smo));
1001 bcopy(smo, db->db_data, sizeof (*smo));
1002 dmu_buf_rele(db, FTAG);
1003
1004 dmu_tx_commit(tx);
1005 }
1006
1007 /*
1008 * Called after a transaction group has completely synced to mark
1009 * all of the metaslab's free space as usable.
1010 */
1011 void
metaslab_sync_done(metaslab_t * msp,uint64_t txg)1012 metaslab_sync_done(metaslab_t *msp, uint64_t txg)
1013 {
1014 space_map_obj_t *smo = &msp->ms_smo;
1015 space_map_obj_t *smosync = &msp->ms_smo_syncing;
1016 space_map_t *sm = &msp->ms_map;
1017 space_map_t *freed_map = &msp->ms_freemap[TXG_CLEAN(txg) & TXG_MASK];
1018 space_map_t *defer_map = &msp->ms_defermap[txg % TXG_DEFER_SIZE];
1019 metaslab_group_t *mg = msp->ms_group;
1020 vdev_t *vd = mg->mg_vd;
1021 int64_t alloc_delta, defer_delta;
1022
1023 ASSERT(!vd->vdev_ishole);
1024
1025 mutex_enter(&msp->ms_lock);
1026
1027 /*
1028 * If this metaslab is just becoming available, initialize its
1029 * allocmaps and freemaps and add its capacity to the vdev.
1030 */
1031 if (freed_map->sm_size == 0) {
1032 for (int t = 0; t < TXG_SIZE; t++) {
1033 space_map_create(&msp->ms_allocmap[t], sm->sm_start,
1034 sm->sm_size, sm->sm_shift, sm->sm_lock);
1035 space_map_create(&msp->ms_freemap[t], sm->sm_start,
1036 sm->sm_size, sm->sm_shift, sm->sm_lock);
1037 }
1038
1039 for (int t = 0; t < TXG_DEFER_SIZE; t++)
1040 space_map_create(&msp->ms_defermap[t], sm->sm_start,
1041 sm->sm_size, sm->sm_shift, sm->sm_lock);
1042
1043 vdev_space_update(vd, 0, 0, sm->sm_size);
1044 }
1045
1046 alloc_delta = smosync->smo_alloc - smo->smo_alloc;
1047 defer_delta = freed_map->sm_space - defer_map->sm_space;
1048
1049 vdev_space_update(vd, alloc_delta + defer_delta, defer_delta, 0);
1050
1051 ASSERT(msp->ms_allocmap[txg & TXG_MASK].sm_space == 0);
1052 ASSERT(msp->ms_freemap[txg & TXG_MASK].sm_space == 0);
1053
1054 /*
1055 * If there's a space_map_load() in progress, wait for it to complete
1056 * so that we have a consistent view of the in-core space map.
1057 * Then, add defer_map (oldest deferred frees) to this map and
1058 * transfer freed_map (this txg's frees) to defer_map.
1059 */
1060 space_map_load_wait(sm);
1061 space_map_vacate(defer_map, sm->sm_loaded ? space_map_free : NULL, sm);
1062 space_map_vacate(freed_map, space_map_add, defer_map);
1063
1064 *smo = *smosync;
1065
1066 msp->ms_deferspace += defer_delta;
1067 ASSERT3S(msp->ms_deferspace, >=, 0);
1068 ASSERT3S(msp->ms_deferspace, <=, sm->sm_size);
1069 if (msp->ms_deferspace != 0) {
1070 /*
1071 * Keep syncing this metaslab until all deferred frees
1072 * are back in circulation.
1073 */
1074 vdev_dirty(vd, VDD_METASLAB, msp, txg + 1);
1075 }
1076
1077 /*
1078 * If the map is loaded but no longer active, evict it as soon as all
1079 * future allocations have synced. (If we unloaded it now and then
1080 * loaded a moment later, the map wouldn't reflect those allocations.)
1081 */
1082 if (sm->sm_loaded && (msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
1083 int evictable = 1;
1084
1085 for (int t = 1; t < TXG_CONCURRENT_STATES; t++)
1086 if (msp->ms_allocmap[(txg + t) & TXG_MASK].sm_space)
1087 evictable = 0;
1088
1089 if (evictable && !metaslab_debug)
1090 space_map_unload(sm);
1091 }
1092
1093 metaslab_group_sort(mg, msp, metaslab_weight(msp));
1094
1095 mutex_exit(&msp->ms_lock);
1096 }
1097
1098 void
metaslab_sync_reassess(metaslab_group_t * mg)1099 metaslab_sync_reassess(metaslab_group_t *mg)
1100 {
1101 vdev_t *vd = mg->mg_vd;
1102
1103 /*
1104 * Re-evaluate all metaslabs which have lower offsets than the
1105 * bonus area.
1106 */
1107 for (int m = 0; m < vd->vdev_ms_count; m++) {
1108 metaslab_t *msp = vd->vdev_ms[m];
1109
1110 if (msp->ms_map.sm_start > mg->mg_bonus_area)
1111 break;
1112
1113 mutex_enter(&msp->ms_lock);
1114 metaslab_group_sort(mg, msp, metaslab_weight(msp));
1115 mutex_exit(&msp->ms_lock);
1116 }
1117
1118 /*
1119 * Prefetch the next potential metaslabs
1120 */
1121 metaslab_prefetch(mg);
1122 }
1123
1124 static uint64_t
metaslab_distance(metaslab_t * msp,dva_t * dva)1125 metaslab_distance(metaslab_t *msp, dva_t *dva)
1126 {
1127 uint64_t ms_shift = msp->ms_group->mg_vd->vdev_ms_shift;
1128 uint64_t offset = DVA_GET_OFFSET(dva) >> ms_shift;
1129 uint64_t start = msp->ms_map.sm_start >> ms_shift;
1130
1131 if (msp->ms_group->mg_vd->vdev_id != DVA_GET_VDEV(dva))
1132 return (1ULL << 63);
1133
1134 if (offset < start)
1135 return ((start - offset) << ms_shift);
1136 if (offset > start)
1137 return ((offset - start) << ms_shift);
1138 return (0);
1139 }
1140
1141 static uint64_t
metaslab_group_alloc(metaslab_group_t * mg,uint64_t size,uint64_t txg,uint64_t min_distance,dva_t * dva,int d)1142 metaslab_group_alloc(metaslab_group_t *mg, uint64_t size, uint64_t txg,
1143 uint64_t min_distance, dva_t *dva, int d)
1144 {
1145 metaslab_t *msp = NULL;
1146 uint64_t offset = -1ULL;
1147 avl_tree_t *t = &mg->mg_metaslab_tree;
1148 uint64_t activation_weight;
1149 uint64_t target_distance;
1150 int i;
1151
1152 activation_weight = METASLAB_WEIGHT_PRIMARY;
1153 for (i = 0; i < d; i++) {
1154 if (DVA_GET_VDEV(&dva[i]) == mg->mg_vd->vdev_id) {
1155 activation_weight = METASLAB_WEIGHT_SECONDARY;
1156 break;
1157 }
1158 }
1159
1160 for (;;) {
1161 boolean_t was_active;
1162
1163 mutex_enter(&mg->mg_lock);
1164 for (msp = avl_first(t); msp; msp = AVL_NEXT(t, msp)) {
1165 if (msp->ms_weight < size) {
1166 mutex_exit(&mg->mg_lock);
1167 return (-1ULL);
1168 }
1169
1170 was_active = msp->ms_weight & METASLAB_ACTIVE_MASK;
1171 if (activation_weight == METASLAB_WEIGHT_PRIMARY)
1172 break;
1173
1174 target_distance = min_distance +
1175 (msp->ms_smo.smo_alloc ? 0 : min_distance >> 1);
1176
1177 for (i = 0; i < d; i++)
1178 if (metaslab_distance(msp, &dva[i]) <
1179 target_distance)
1180 break;
1181 if (i == d)
1182 break;
1183 }
1184 mutex_exit(&mg->mg_lock);
1185 if (msp == NULL)
1186 return (-1ULL);
1187
1188 mutex_enter(&msp->ms_lock);
1189
1190 /*
1191 * Ensure that the metaslab we have selected is still
1192 * capable of handling our request. It's possible that
1193 * another thread may have changed the weight while we
1194 * were blocked on the metaslab lock.
1195 */
1196 if (msp->ms_weight < size || (was_active &&
1197 !(msp->ms_weight & METASLAB_ACTIVE_MASK) &&
1198 activation_weight == METASLAB_WEIGHT_PRIMARY)) {
1199 mutex_exit(&msp->ms_lock);
1200 continue;
1201 }
1202
1203 if ((msp->ms_weight & METASLAB_WEIGHT_SECONDARY) &&
1204 activation_weight == METASLAB_WEIGHT_PRIMARY) {
1205 metaslab_passivate(msp,
1206 msp->ms_weight & ~METASLAB_ACTIVE_MASK);
1207 mutex_exit(&msp->ms_lock);
1208 continue;
1209 }
1210
1211 if (metaslab_activate(msp, activation_weight, size) != 0) {
1212 mutex_exit(&msp->ms_lock);
1213 continue;
1214 }
1215
1216 if ((offset = space_map_alloc(&msp->ms_map, size)) != -1ULL)
1217 break;
1218
1219 metaslab_passivate(msp, space_map_maxsize(&msp->ms_map));
1220
1221 mutex_exit(&msp->ms_lock);
1222 }
1223
1224 if (msp->ms_allocmap[txg & TXG_MASK].sm_space == 0)
1225 vdev_dirty(mg->mg_vd, VDD_METASLAB, msp, txg);
1226
1227 space_map_add(&msp->ms_allocmap[txg & TXG_MASK], offset, size);
1228
1229 mutex_exit(&msp->ms_lock);
1230
1231 return (offset);
1232 }
1233
1234 /*
1235 * Allocate a block for the specified i/o.
1236 */
1237 static int
metaslab_alloc_dva(spa_t * spa,metaslab_class_t * mc,uint64_t psize,dva_t * dva,int d,dva_t * hintdva,uint64_t txg,int flags)1238 metaslab_alloc_dva(spa_t *spa, metaslab_class_t *mc, uint64_t psize,
1239 dva_t *dva, int d, dva_t *hintdva, uint64_t txg, int flags)
1240 {
1241 metaslab_group_t *mg, *rotor;
1242 vdev_t *vd;
1243 int dshift = 3;
1244 int all_zero;
1245 int zio_lock = B_FALSE;
1246 boolean_t allocatable;
1247 uint64_t offset = -1ULL;
1248 uint64_t asize;
1249 uint64_t distance;
1250
1251 ASSERT(!DVA_IS_VALID(&dva[d]));
1252
1253 /*
1254 * For testing, make some blocks above a certain size be gang blocks.
1255 */
1256 if (psize >= metaslab_gang_bang && (ddi_get_lbolt() & 3) == 0)
1257 return (ENOSPC);
1258
1259 /*
1260 * Start at the rotor and loop through all mgs until we find something.
1261 * Note that there's no locking on mc_rotor or mc_aliquot because
1262 * nothing actually breaks if we miss a few updates -- we just won't
1263 * allocate quite as evenly. It all balances out over time.
1264 *
1265 * If we are doing ditto or log blocks, try to spread them across
1266 * consecutive vdevs. If we're forced to reuse a vdev before we've
1267 * allocated all of our ditto blocks, then try and spread them out on
1268 * that vdev as much as possible. If it turns out to not be possible,
1269 * gradually lower our standards until anything becomes acceptable.
1270 * Also, allocating on consecutive vdevs (as opposed to random vdevs)
1271 * gives us hope of containing our fault domains to something we're
1272 * able to reason about. Otherwise, any two top-level vdev failures
1273 * will guarantee the loss of data. With consecutive allocation,
1274 * only two adjacent top-level vdev failures will result in data loss.
1275 *
1276 * If we are doing gang blocks (hintdva is non-NULL), try to keep
1277 * ourselves on the same vdev as our gang block header. That
1278 * way, we can hope for locality in vdev_cache, plus it makes our
1279 * fault domains something tractable.
1280 */
1281 if (hintdva) {
1282 vd = vdev_lookup_top(spa, DVA_GET_VDEV(&hintdva[d]));
1283
1284 /*
1285 * It's possible the vdev we're using as the hint no
1286 * longer exists (i.e. removed). Consult the rotor when
1287 * all else fails.
1288 */
1289 if (vd != NULL) {
1290 mg = vd->vdev_mg;
1291
1292 if (flags & METASLAB_HINTBP_AVOID &&
1293 mg->mg_next != NULL)
1294 mg = mg->mg_next;
1295 } else {
1296 mg = mc->mc_rotor;
1297 }
1298 } else if (d != 0) {
1299 vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[d - 1]));
1300 mg = vd->vdev_mg->mg_next;
1301 } else {
1302 mg = mc->mc_rotor;
1303 }
1304
1305 /*
1306 * If the hint put us into the wrong metaslab class, or into a
1307 * metaslab group that has been passivated, just follow the rotor.
1308 */
1309 if (mg->mg_class != mc || mg->mg_activation_count <= 0)
1310 mg = mc->mc_rotor;
1311
1312 rotor = mg;
1313 top:
1314 all_zero = B_TRUE;
1315 do {
1316 ASSERT(mg->mg_activation_count == 1);
1317
1318 vd = mg->mg_vd;
1319
1320 /*
1321 * Don't allocate from faulted devices.
1322 */
1323 if (zio_lock) {
1324 spa_config_enter(spa, SCL_ZIO, FTAG, RW_READER);
1325 allocatable = vdev_allocatable(vd);
1326 spa_config_exit(spa, SCL_ZIO, FTAG);
1327 } else {
1328 allocatable = vdev_allocatable(vd);
1329 }
1330 if (!allocatable)
1331 goto next;
1332
1333 /*
1334 * Avoid writing single-copy data to a failing vdev
1335 */
1336 if ((vd->vdev_stat.vs_write_errors > 0 ||
1337 vd->vdev_state < VDEV_STATE_HEALTHY) &&
1338 d == 0 && dshift == 3) {
1339 all_zero = B_FALSE;
1340 goto next;
1341 }
1342
1343 ASSERT(mg->mg_class == mc);
1344
1345 distance = vd->vdev_asize >> dshift;
1346 if (distance <= (1ULL << vd->vdev_ms_shift))
1347 distance = 0;
1348 else
1349 all_zero = B_FALSE;
1350
1351 asize = vdev_psize_to_asize(vd, psize);
1352 ASSERT(P2PHASE(asize, 1ULL << vd->vdev_ashift) == 0);
1353
1354 offset = metaslab_group_alloc(mg, asize, txg, distance, dva, d);
1355 if (offset != -1ULL) {
1356 /*
1357 * If we've just selected this metaslab group,
1358 * figure out whether the corresponding vdev is
1359 * over- or under-used relative to the pool,
1360 * and set an allocation bias to even it out.
1361 */
1362 if (mc->mc_aliquot == 0) {
1363 vdev_stat_t *vs = &vd->vdev_stat;
1364 int64_t vu, cu;
1365
1366 /*
1367 * Determine percent used in units of 0..1024.
1368 * (This is just to avoid floating point.)
1369 */
1370 vu = (vs->vs_alloc << 10) / (vs->vs_space + 1);
1371 cu = (mc->mc_alloc << 10) / (mc->mc_space + 1);
1372
1373 /*
1374 * Bias by at most +/- 25% of the aliquot.
1375 */
1376 mg->mg_bias = ((cu - vu) *
1377 (int64_t)mg->mg_aliquot) / (1024 * 4);
1378 }
1379
1380 if (atomic_add_64_nv(&mc->mc_aliquot, asize) >=
1381 mg->mg_aliquot + mg->mg_bias) {
1382 mc->mc_rotor = mg->mg_next;
1383 mc->mc_aliquot = 0;
1384 }
1385
1386 DVA_SET_VDEV(&dva[d], vd->vdev_id);
1387 DVA_SET_OFFSET(&dva[d], offset);
1388 DVA_SET_GANG(&dva[d], !!(flags & METASLAB_GANG_HEADER));
1389 DVA_SET_ASIZE(&dva[d], asize);
1390
1391 return (0);
1392 }
1393 next:
1394 mc->mc_rotor = mg->mg_next;
1395 mc->mc_aliquot = 0;
1396 } while ((mg = mg->mg_next) != rotor);
1397
1398 if (!all_zero) {
1399 dshift++;
1400 ASSERT(dshift < 64);
1401 goto top;
1402 }
1403
1404 if (!allocatable && !zio_lock) {
1405 dshift = 3;
1406 zio_lock = B_TRUE;
1407 goto top;
1408 }
1409
1410 bzero(&dva[d], sizeof (dva_t));
1411
1412 return (ENOSPC);
1413 }
1414
1415 /*
1416 * Free the block represented by DVA in the context of the specified
1417 * transaction group.
1418 */
1419 static void
metaslab_free_dva(spa_t * spa,const dva_t * dva,uint64_t txg,boolean_t now)1420 metaslab_free_dva(spa_t *spa, const dva_t *dva, uint64_t txg, boolean_t now)
1421 {
1422 uint64_t vdev = DVA_GET_VDEV(dva);
1423 uint64_t offset = DVA_GET_OFFSET(dva);
1424 uint64_t size = DVA_GET_ASIZE(dva);
1425 vdev_t *vd;
1426 metaslab_t *msp;
1427
1428 ASSERT(DVA_IS_VALID(dva));
1429
1430 if (txg > spa_freeze_txg(spa))
1431 return;
1432
1433 if ((vd = vdev_lookup_top(spa, vdev)) == NULL ||
1434 (offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count) {
1435 cmn_err(CE_WARN, "metaslab_free_dva(): bad DVA %llu:%llu",
1436 (u_longlong_t)vdev, (u_longlong_t)offset);
1437 ASSERT(0);
1438 return;
1439 }
1440
1441 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
1442
1443 if (DVA_GET_GANG(dva))
1444 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
1445
1446 mutex_enter(&msp->ms_lock);
1447
1448 if (now) {
1449 space_map_remove(&msp->ms_allocmap[txg & TXG_MASK],
1450 offset, size);
1451 space_map_free(&msp->ms_map, offset, size);
1452 } else {
1453 if (msp->ms_freemap[txg & TXG_MASK].sm_space == 0)
1454 vdev_dirty(vd, VDD_METASLAB, msp, txg);
1455 space_map_add(&msp->ms_freemap[txg & TXG_MASK], offset, size);
1456 }
1457
1458 mutex_exit(&msp->ms_lock);
1459 }
1460
1461 /*
1462 * Intent log support: upon opening the pool after a crash, notify the SPA
1463 * of blocks that the intent log has allocated for immediate write, but
1464 * which are still considered free by the SPA because the last transaction
1465 * group didn't commit yet.
1466 */
1467 static int
metaslab_claim_dva(spa_t * spa,const dva_t * dva,uint64_t txg)1468 metaslab_claim_dva(spa_t *spa, const dva_t *dva, uint64_t txg)
1469 {
1470 uint64_t vdev = DVA_GET_VDEV(dva);
1471 uint64_t offset = DVA_GET_OFFSET(dva);
1472 uint64_t size = DVA_GET_ASIZE(dva);
1473 vdev_t *vd;
1474 metaslab_t *msp;
1475 int error = 0;
1476
1477 ASSERT(DVA_IS_VALID(dva));
1478
1479 if ((vd = vdev_lookup_top(spa, vdev)) == NULL ||
1480 (offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count)
1481 return (ENXIO);
1482
1483 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
1484
1485 if (DVA_GET_GANG(dva))
1486 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
1487
1488 mutex_enter(&msp->ms_lock);
1489
1490 if ((txg != 0 && spa_writeable(spa)) || !msp->ms_map.sm_loaded)
1491 error = metaslab_activate(msp, METASLAB_WEIGHT_SECONDARY, 0);
1492
1493 if (error == 0 && !space_map_contains(&msp->ms_map, offset, size))
1494 error = ENOENT;
1495
1496 if (error || txg == 0) { /* txg == 0 indicates dry run */
1497 mutex_exit(&msp->ms_lock);
1498 return (error);
1499 }
1500
1501 space_map_claim(&msp->ms_map, offset, size);
1502
1503 if (spa_writeable(spa)) { /* don't dirty if we're zdb(1M) */
1504 if (msp->ms_allocmap[txg & TXG_MASK].sm_space == 0)
1505 vdev_dirty(vd, VDD_METASLAB, msp, txg);
1506 space_map_add(&msp->ms_allocmap[txg & TXG_MASK], offset, size);
1507 }
1508
1509 mutex_exit(&msp->ms_lock);
1510
1511 return (0);
1512 }
1513
1514 int
metaslab_alloc(spa_t * spa,metaslab_class_t * mc,uint64_t psize,blkptr_t * bp,int ndvas,uint64_t txg,blkptr_t * hintbp,int flags)1515 metaslab_alloc(spa_t *spa, metaslab_class_t *mc, uint64_t psize, blkptr_t *bp,
1516 int ndvas, uint64_t txg, blkptr_t *hintbp, int flags)
1517 {
1518 dva_t *dva = bp->blk_dva;
1519 dva_t *hintdva = hintbp->blk_dva;
1520 int error = 0;
1521
1522 ASSERT(bp->blk_birth == 0);
1523 ASSERT(BP_PHYSICAL_BIRTH(bp) == 0);
1524
1525 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
1526
1527 if (mc->mc_rotor == NULL) { /* no vdevs in this class */
1528 spa_config_exit(spa, SCL_ALLOC, FTAG);
1529 return (ENOSPC);
1530 }
1531
1532 ASSERT(ndvas > 0 && ndvas <= spa_max_replication(spa));
1533 ASSERT(BP_GET_NDVAS(bp) == 0);
1534 ASSERT(hintbp == NULL || ndvas <= BP_GET_NDVAS(hintbp));
1535
1536 for (int d = 0; d < ndvas; d++) {
1537 error = metaslab_alloc_dva(spa, mc, psize, dva, d, hintdva,
1538 txg, flags);
1539 if (error) {
1540 for (d--; d >= 0; d--) {
1541 metaslab_free_dva(spa, &dva[d], txg, B_TRUE);
1542 bzero(&dva[d], sizeof (dva_t));
1543 }
1544 spa_config_exit(spa, SCL_ALLOC, FTAG);
1545 return (error);
1546 }
1547 }
1548 ASSERT(error == 0);
1549 ASSERT(BP_GET_NDVAS(bp) == ndvas);
1550
1551 spa_config_exit(spa, SCL_ALLOC, FTAG);
1552
1553 BP_SET_BIRTH(bp, txg, txg);
1554
1555 return (0);
1556 }
1557
1558 void
metaslab_free(spa_t * spa,const blkptr_t * bp,uint64_t txg,boolean_t now)1559 metaslab_free(spa_t *spa, const blkptr_t *bp, uint64_t txg, boolean_t now)
1560 {
1561 const dva_t *dva = bp->blk_dva;
1562 int ndvas = BP_GET_NDVAS(bp);
1563
1564 ASSERT(!BP_IS_HOLE(bp));
1565 ASSERT(!now || bp->blk_birth >= spa_syncing_txg(spa));
1566
1567 spa_config_enter(spa, SCL_FREE, FTAG, RW_READER);
1568
1569 for (int d = 0; d < ndvas; d++)
1570 metaslab_free_dva(spa, &dva[d], txg, now);
1571
1572 spa_config_exit(spa, SCL_FREE, FTAG);
1573 }
1574
1575 int
metaslab_claim(spa_t * spa,const blkptr_t * bp,uint64_t txg)1576 metaslab_claim(spa_t *spa, const blkptr_t *bp, uint64_t txg)
1577 {
1578 const dva_t *dva = bp->blk_dva;
1579 int ndvas = BP_GET_NDVAS(bp);
1580 int error = 0;
1581
1582 ASSERT(!BP_IS_HOLE(bp));
1583
1584 if (txg != 0) {
1585 /*
1586 * First do a dry run to make sure all DVAs are claimable,
1587 * so we don't have to unwind from partial failures below.
1588 */
1589 if ((error = metaslab_claim(spa, bp, 0)) != 0)
1590 return (error);
1591 }
1592
1593 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
1594
1595 for (int d = 0; d < ndvas; d++)
1596 if ((error = metaslab_claim_dva(spa, &dva[d], txg)) != 0)
1597 break;
1598
1599 spa_config_exit(spa, SCL_ALLOC, FTAG);
1600
1601 ASSERT(error == 0 || txg == 0);
1602
1603 return (error);
1604 }
1605