metaslab.c revision 331395
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 38SYSCTL_DECL(_vfs_zfs); 39SYSCTL_NODE(_vfs_zfs, OID_AUTO, metaslab, CTLFLAG_RW, 0, "ZFS metaslab"); 40 41#define GANG_ALLOCATION(flags) \ 42 ((flags) & (METASLAB_GANG_CHILD | METASLAB_GANG_HEADER)) 43 44uint64_t metaslab_aliquot = 512ULL << 10; 45uint64_t metaslab_gang_bang = SPA_MAXBLOCKSIZE + 1; /* force gang blocks */ 46SYSCTL_QUAD(_vfs_zfs_metaslab, OID_AUTO, gang_bang, CTLFLAG_RWTUN, 47 &metaslab_gang_bang, 0, 48 "Force gang block allocation for blocks larger than or equal to this value"); 49 50/* 51 * The in-core space map representation is more compact than its on-disk form. 52 * The zfs_condense_pct determines how much more compact the in-core 53 * space map representation must be before we compact it on-disk. 54 * Values should be greater than or equal to 100. 55 */ 56int zfs_condense_pct = 200; 57SYSCTL_INT(_vfs_zfs, OID_AUTO, condense_pct, CTLFLAG_RWTUN, 58 &zfs_condense_pct, 0, 59 "Condense on-disk spacemap when it is more than this many percents" 60 " of in-memory counterpart"); 61 62/* 63 * Condensing a metaslab is not guaranteed to actually reduce the amount of 64 * space used on disk. In particular, a space map uses data in increments of 65 * MAX(1 << ashift, space_map_blksize), so a metaslab might use the 66 * same number of blocks after condensing. Since the goal of condensing is to 67 * reduce the number of IOPs required to read the space map, we only want to 68 * condense when we can be sure we will reduce the number of blocks used by the 69 * space map. Unfortunately, we cannot precisely compute whether or not this is 70 * the case in metaslab_should_condense since we are holding ms_lock. Instead, 71 * we apply the following heuristic: do not condense a spacemap unless the 72 * uncondensed size consumes greater than zfs_metaslab_condense_block_threshold 73 * blocks. 74 */ 75int zfs_metaslab_condense_block_threshold = 4; 76 77/* 78 * The zfs_mg_noalloc_threshold defines which metaslab groups should 79 * be eligible for allocation. The value is defined as a percentage of 80 * free space. Metaslab groups that have more free space than 81 * zfs_mg_noalloc_threshold are always eligible for allocations. Once 82 * a metaslab group's free space is less than or equal to the 83 * zfs_mg_noalloc_threshold the allocator will avoid allocating to that 84 * group unless all groups in the pool have reached zfs_mg_noalloc_threshold. 85 * Once all groups in the pool reach zfs_mg_noalloc_threshold then all 86 * groups are allowed to accept allocations. Gang blocks are always 87 * eligible to allocate on any metaslab group. The default value of 0 means 88 * no metaslab group will be excluded based on this criterion. 89 */ 90int zfs_mg_noalloc_threshold = 0; 91SYSCTL_INT(_vfs_zfs, OID_AUTO, mg_noalloc_threshold, CTLFLAG_RWTUN, 92 &zfs_mg_noalloc_threshold, 0, 93 "Percentage of metaslab group size that should be free" 94 " to make it eligible for allocation"); 95 96/* 97 * Metaslab groups are considered eligible for allocations if their 98 * fragmenation metric (measured as a percentage) is less than or equal to 99 * zfs_mg_fragmentation_threshold. If a metaslab group exceeds this threshold 100 * then it will be skipped unless all metaslab groups within the metaslab 101 * class have also crossed this threshold. 102 */ 103int zfs_mg_fragmentation_threshold = 85; 104SYSCTL_INT(_vfs_zfs, OID_AUTO, mg_fragmentation_threshold, CTLFLAG_RWTUN, 105 &zfs_mg_fragmentation_threshold, 0, 106 "Percentage of metaslab group size that should be considered " 107 "eligible for allocations unless all metaslab groups within the metaslab class " 108 "have also crossed this threshold"); 109 110/* 111 * Allow metaslabs to keep their active state as long as their fragmentation 112 * percentage is less than or equal to zfs_metaslab_fragmentation_threshold. An 113 * active metaslab that exceeds this threshold will no longer keep its active 114 * status allowing better metaslabs to be selected. 115 */ 116int zfs_metaslab_fragmentation_threshold = 70; 117SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, fragmentation_threshold, CTLFLAG_RWTUN, 118 &zfs_metaslab_fragmentation_threshold, 0, 119 "Maximum percentage of metaslab fragmentation level to keep their active state"); 120 121/* 122 * When set will load all metaslabs when pool is first opened. 123 */ 124int metaslab_debug_load = 0; 125SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, debug_load, CTLFLAG_RWTUN, 126 &metaslab_debug_load, 0, 127 "Load all metaslabs when pool is first opened"); 128 129/* 130 * When set will prevent metaslabs from being unloaded. 131 */ 132int metaslab_debug_unload = 0; 133SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, debug_unload, CTLFLAG_RWTUN, 134 &metaslab_debug_unload, 0, 135 "Prevent metaslabs from being unloaded"); 136 137/* 138 * Minimum size which forces the dynamic allocator to change 139 * it's allocation strategy. Once the space map cannot satisfy 140 * an allocation of this size then it switches to using more 141 * aggressive strategy (i.e search by size rather than offset). 142 */ 143uint64_t metaslab_df_alloc_threshold = SPA_OLD_MAXBLOCKSIZE; 144SYSCTL_QUAD(_vfs_zfs_metaslab, OID_AUTO, df_alloc_threshold, CTLFLAG_RWTUN, 145 &metaslab_df_alloc_threshold, 0, 146 "Minimum size which forces the dynamic allocator to change it's allocation strategy"); 147 148/* 149 * The minimum free space, in percent, which must be available 150 * in a space map to continue allocations in a first-fit fashion. 151 * Once the space map's free space drops below this level we dynamically 152 * switch to using best-fit allocations. 153 */ 154int metaslab_df_free_pct = 4; 155SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, df_free_pct, CTLFLAG_RWTUN, 156 &metaslab_df_free_pct, 0, 157 "The minimum free space, in percent, which must be available in a " 158 "space map to continue allocations in a first-fit fashion"); 159 160/* 161 * A metaslab is considered "free" if it contains a contiguous 162 * segment which is greater than metaslab_min_alloc_size. 163 */ 164uint64_t metaslab_min_alloc_size = DMU_MAX_ACCESS; 165SYSCTL_QUAD(_vfs_zfs_metaslab, OID_AUTO, min_alloc_size, CTLFLAG_RWTUN, 166 &metaslab_min_alloc_size, 0, 167 "A metaslab is considered \"free\" if it contains a contiguous " 168 "segment which is greater than vfs.zfs.metaslab.min_alloc_size"); 169 170/* 171 * Percentage of all cpus that can be used by the metaslab taskq. 172 */ 173int metaslab_load_pct = 50; 174SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, load_pct, CTLFLAG_RWTUN, 175 &metaslab_load_pct, 0, 176 "Percentage of cpus that can be used by the metaslab taskq"); 177 178/* 179 * Determines how many txgs a metaslab may remain loaded without having any 180 * allocations from it. As long as a metaslab continues to be used we will 181 * keep it loaded. 182 */ 183int metaslab_unload_delay = TXG_SIZE * 2; 184SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, unload_delay, CTLFLAG_RWTUN, 185 &metaslab_unload_delay, 0, 186 "Number of TXGs that an unused metaslab can be kept in memory"); 187 188/* 189 * Max number of metaslabs per group to preload. 190 */ 191int metaslab_preload_limit = SPA_DVAS_PER_BP; 192SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, preload_limit, CTLFLAG_RWTUN, 193 &metaslab_preload_limit, 0, 194 "Max number of metaslabs per group to preload"); 195 196/* 197 * Enable/disable preloading of metaslab. 198 */ 199boolean_t metaslab_preload_enabled = B_TRUE; 200SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, preload_enabled, CTLFLAG_RWTUN, 201 &metaslab_preload_enabled, 0, 202 "Max number of metaslabs per group to preload"); 203 204/* 205 * Enable/disable fragmentation weighting on metaslabs. 206 */ 207boolean_t metaslab_fragmentation_factor_enabled = B_TRUE; 208SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, fragmentation_factor_enabled, CTLFLAG_RWTUN, 209 &metaslab_fragmentation_factor_enabled, 0, 210 "Enable fragmentation weighting on metaslabs"); 211 212/* 213 * Enable/disable lba weighting (i.e. outer tracks are given preference). 214 */ 215boolean_t metaslab_lba_weighting_enabled = B_TRUE; 216SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, lba_weighting_enabled, CTLFLAG_RWTUN, 217 &metaslab_lba_weighting_enabled, 0, 218 "Enable LBA weighting (i.e. outer tracks are given preference)"); 219 220/* 221 * Enable/disable metaslab group biasing. 222 */ 223boolean_t metaslab_bias_enabled = B_TRUE; 224SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, bias_enabled, CTLFLAG_RWTUN, 225 &metaslab_bias_enabled, 0, 226 "Enable metaslab group biasing"); 227 228/* 229 * Enable/disable segment-based metaslab selection. 230 */ 231boolean_t zfs_metaslab_segment_weight_enabled = B_TRUE; 232 233/* 234 * When using segment-based metaslab selection, we will continue 235 * allocating from the active metaslab until we have exhausted 236 * zfs_metaslab_switch_threshold of its buckets. 237 */ 238int zfs_metaslab_switch_threshold = 2; 239 240/* 241 * Internal switch to enable/disable the metaslab allocation tracing 242 * facility. 243 */ 244boolean_t metaslab_trace_enabled = B_TRUE; 245 246/* 247 * Maximum entries that the metaslab allocation tracing facility will keep 248 * in a given list when running in non-debug mode. We limit the number 249 * of entries in non-debug mode to prevent us from using up too much memory. 250 * The limit should be sufficiently large that we don't expect any allocation 251 * to every exceed this value. In debug mode, the system will panic if this 252 * limit is ever reached allowing for further investigation. 253 */ 254uint64_t metaslab_trace_max_entries = 5000; 255 256static uint64_t metaslab_weight(metaslab_t *); 257static void metaslab_set_fragmentation(metaslab_t *); 258 259kmem_cache_t *metaslab_alloc_trace_cache; 260 261/* 262 * ========================================================================== 263 * Metaslab classes 264 * ========================================================================== 265 */ 266metaslab_class_t * 267metaslab_class_create(spa_t *spa, metaslab_ops_t *ops) 268{ 269 metaslab_class_t *mc; 270 271 mc = kmem_zalloc(sizeof (metaslab_class_t), KM_SLEEP); 272 273 mc->mc_spa = spa; 274 mc->mc_rotor = NULL; 275 mc->mc_ops = ops; 276 mutex_init(&mc->mc_lock, NULL, MUTEX_DEFAULT, NULL); 277 refcount_create_tracked(&mc->mc_alloc_slots); 278 279 return (mc); 280} 281 282void 283metaslab_class_destroy(metaslab_class_t *mc) 284{ 285 ASSERT(mc->mc_rotor == NULL); 286 ASSERT(mc->mc_alloc == 0); 287 ASSERT(mc->mc_deferred == 0); 288 ASSERT(mc->mc_space == 0); 289 ASSERT(mc->mc_dspace == 0); 290 291 refcount_destroy(&mc->mc_alloc_slots); 292 mutex_destroy(&mc->mc_lock); 293 kmem_free(mc, sizeof (metaslab_class_t)); 294} 295 296int 297metaslab_class_validate(metaslab_class_t *mc) 298{ 299 metaslab_group_t *mg; 300 vdev_t *vd; 301 302 /* 303 * Must hold one of the spa_config locks. 304 */ 305 ASSERT(spa_config_held(mc->mc_spa, SCL_ALL, RW_READER) || 306 spa_config_held(mc->mc_spa, SCL_ALL, RW_WRITER)); 307 308 if ((mg = mc->mc_rotor) == NULL) 309 return (0); 310 311 do { 312 vd = mg->mg_vd; 313 ASSERT(vd->vdev_mg != NULL); 314 ASSERT3P(vd->vdev_top, ==, vd); 315 ASSERT3P(mg->mg_class, ==, mc); 316 ASSERT3P(vd->vdev_ops, !=, &vdev_hole_ops); 317 } while ((mg = mg->mg_next) != mc->mc_rotor); 318 319 return (0); 320} 321 322void 323metaslab_class_space_update(metaslab_class_t *mc, int64_t alloc_delta, 324 int64_t defer_delta, int64_t space_delta, int64_t dspace_delta) 325{ 326 atomic_add_64(&mc->mc_alloc, alloc_delta); 327 atomic_add_64(&mc->mc_deferred, defer_delta); 328 atomic_add_64(&mc->mc_space, space_delta); 329 atomic_add_64(&mc->mc_dspace, dspace_delta); 330} 331 332void 333metaslab_class_minblocksize_update(metaslab_class_t *mc) 334{ 335 metaslab_group_t *mg; 336 vdev_t *vd; 337 uint64_t minashift = UINT64_MAX; 338 339 if ((mg = mc->mc_rotor) == NULL) { 340 mc->mc_minblocksize = SPA_MINBLOCKSIZE; 341 return; 342 } 343 344 do { 345 vd = mg->mg_vd; 346 if (vd->vdev_ashift < minashift) 347 minashift = vd->vdev_ashift; 348 } while ((mg = mg->mg_next) != mc->mc_rotor); 349 350 mc->mc_minblocksize = 1ULL << minashift; 351} 352 353uint64_t 354metaslab_class_get_alloc(metaslab_class_t *mc) 355{ 356 return (mc->mc_alloc); 357} 358 359uint64_t 360metaslab_class_get_deferred(metaslab_class_t *mc) 361{ 362 return (mc->mc_deferred); 363} 364 365uint64_t 366metaslab_class_get_space(metaslab_class_t *mc) 367{ 368 return (mc->mc_space); 369} 370 371uint64_t 372metaslab_class_get_dspace(metaslab_class_t *mc) 373{ 374 return (spa_deflate(mc->mc_spa) ? mc->mc_dspace : mc->mc_space); 375} 376 377uint64_t 378metaslab_class_get_minblocksize(metaslab_class_t *mc) 379{ 380 return (mc->mc_minblocksize); 381} 382 383void 384metaslab_class_histogram_verify(metaslab_class_t *mc) 385{ 386 vdev_t *rvd = mc->mc_spa->spa_root_vdev; 387 uint64_t *mc_hist; 388 int i; 389 390 if ((zfs_flags & ZFS_DEBUG_HISTOGRAM_VERIFY) == 0) 391 return; 392 393 mc_hist = kmem_zalloc(sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE, 394 KM_SLEEP); 395 396 for (int c = 0; c < rvd->vdev_children; c++) { 397 vdev_t *tvd = rvd->vdev_child[c]; 398 metaslab_group_t *mg = tvd->vdev_mg; 399 400 /* 401 * Skip any holes, uninitialized top-levels, or 402 * vdevs that are not in this metalab class. 403 */ 404 if (tvd->vdev_ishole || tvd->vdev_ms_shift == 0 || 405 mg->mg_class != mc) { 406 continue; 407 } 408 409 for (i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i++) 410 mc_hist[i] += mg->mg_histogram[i]; 411 } 412 413 for (i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i++) 414 VERIFY3U(mc_hist[i], ==, mc->mc_histogram[i]); 415 416 kmem_free(mc_hist, sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE); 417} 418 419/* 420 * Calculate the metaslab class's fragmentation metric. The metric 421 * is weighted based on the space contribution of each metaslab group. 422 * The return value will be a number between 0 and 100 (inclusive), or 423 * ZFS_FRAG_INVALID if the metric has not been set. See comment above the 424 * zfs_frag_table for more information about the metric. 425 */ 426uint64_t 427metaslab_class_fragmentation(metaslab_class_t *mc) 428{ 429 vdev_t *rvd = mc->mc_spa->spa_root_vdev; 430 uint64_t fragmentation = 0; 431 432 spa_config_enter(mc->mc_spa, SCL_VDEV, FTAG, RW_READER); 433 434 for (int c = 0; c < rvd->vdev_children; c++) { 435 vdev_t *tvd = rvd->vdev_child[c]; 436 metaslab_group_t *mg = tvd->vdev_mg; 437 438 /* 439 * Skip any holes, uninitialized top-levels, or 440 * vdevs that are not in this metalab class. 441 */ 442 if (tvd->vdev_ishole || tvd->vdev_ms_shift == 0 || 443 mg->mg_class != mc) { 444 continue; 445 } 446 447 /* 448 * If a metaslab group does not contain a fragmentation 449 * metric then just bail out. 450 */ 451 if (mg->mg_fragmentation == ZFS_FRAG_INVALID) { 452 spa_config_exit(mc->mc_spa, SCL_VDEV, FTAG); 453 return (ZFS_FRAG_INVALID); 454 } 455 456 /* 457 * Determine how much this metaslab_group is contributing 458 * to the overall pool fragmentation metric. 459 */ 460 fragmentation += mg->mg_fragmentation * 461 metaslab_group_get_space(mg); 462 } 463 fragmentation /= metaslab_class_get_space(mc); 464 465 ASSERT3U(fragmentation, <=, 100); 466 spa_config_exit(mc->mc_spa, SCL_VDEV, FTAG); 467 return (fragmentation); 468} 469 470/* 471 * Calculate the amount of expandable space that is available in 472 * this metaslab class. If a device is expanded then its expandable 473 * space will be the amount of allocatable space that is currently not 474 * part of this metaslab class. 475 */ 476uint64_t 477metaslab_class_expandable_space(metaslab_class_t *mc) 478{ 479 vdev_t *rvd = mc->mc_spa->spa_root_vdev; 480 uint64_t space = 0; 481 482 spa_config_enter(mc->mc_spa, SCL_VDEV, FTAG, RW_READER); 483 for (int c = 0; c < rvd->vdev_children; c++) { 484 uint64_t tspace; 485 vdev_t *tvd = rvd->vdev_child[c]; 486 metaslab_group_t *mg = tvd->vdev_mg; 487 488 if (tvd->vdev_ishole || tvd->vdev_ms_shift == 0 || 489 mg->mg_class != mc) { 490 continue; 491 } 492 493 /* 494 * Calculate if we have enough space to add additional 495 * metaslabs. We report the expandable space in terms 496 * of the metaslab size since that's the unit of expansion. 497 * Adjust by efi system partition size. 498 */ 499 tspace = tvd->vdev_max_asize - tvd->vdev_asize; 500 if (tspace > mc->mc_spa->spa_bootsize) { 501 tspace -= mc->mc_spa->spa_bootsize; 502 } 503 space += P2ALIGN(tspace, 1ULL << tvd->vdev_ms_shift); 504 } 505 spa_config_exit(mc->mc_spa, SCL_VDEV, FTAG); 506 return (space); 507} 508 509static int 510metaslab_compare(const void *x1, const void *x2) 511{ 512 const metaslab_t *m1 = x1; 513 const metaslab_t *m2 = x2; 514 515 if (m1->ms_weight < m2->ms_weight) 516 return (1); 517 if (m1->ms_weight > m2->ms_weight) 518 return (-1); 519 520 /* 521 * If the weights are identical, use the offset to force uniqueness. 522 */ 523 if (m1->ms_start < m2->ms_start) 524 return (-1); 525 if (m1->ms_start > m2->ms_start) 526 return (1); 527 528 ASSERT3P(m1, ==, m2); 529 530 return (0); 531} 532 533/* 534 * Verify that the space accounting on disk matches the in-core range_trees. 535 */ 536void 537metaslab_verify_space(metaslab_t *msp, uint64_t txg) 538{ 539 spa_t *spa = msp->ms_group->mg_vd->vdev_spa; 540 uint64_t allocated = 0; 541 uint64_t sm_free_space, msp_free_space; 542 543 ASSERT(MUTEX_HELD(&msp->ms_lock)); 544 545 if ((zfs_flags & ZFS_DEBUG_METASLAB_VERIFY) == 0) 546 return; 547 548 /* 549 * We can only verify the metaslab space when we're called 550 * from syncing context with a loaded metaslab that has an allocated 551 * space map. Calling this in non-syncing context does not 552 * provide a consistent view of the metaslab since we're performing 553 * allocations in the future. 554 */ 555 if (txg != spa_syncing_txg(spa) || msp->ms_sm == NULL || 556 !msp->ms_loaded) 557 return; 558 559 sm_free_space = msp->ms_size - space_map_allocated(msp->ms_sm) - 560 space_map_alloc_delta(msp->ms_sm); 561 562 /* 563 * Account for future allocations since we would have already 564 * deducted that space from the ms_freetree. 565 */ 566 for (int t = 0; t < TXG_CONCURRENT_STATES; t++) { 567 allocated += 568 range_tree_space(msp->ms_alloctree[(txg + t) & TXG_MASK]); 569 } 570 571 msp_free_space = range_tree_space(msp->ms_tree) + allocated + 572 msp->ms_deferspace + range_tree_space(msp->ms_freedtree); 573 574 VERIFY3U(sm_free_space, ==, msp_free_space); 575} 576 577/* 578 * ========================================================================== 579 * Metaslab groups 580 * ========================================================================== 581 */ 582/* 583 * Update the allocatable flag and the metaslab group's capacity. 584 * The allocatable flag is set to true if the capacity is below 585 * the zfs_mg_noalloc_threshold or has a fragmentation value that is 586 * greater than zfs_mg_fragmentation_threshold. If a metaslab group 587 * transitions from allocatable to non-allocatable or vice versa then the 588 * metaslab group's class is updated to reflect the transition. 589 */ 590static void 591metaslab_group_alloc_update(metaslab_group_t *mg) 592{ 593 vdev_t *vd = mg->mg_vd; 594 metaslab_class_t *mc = mg->mg_class; 595 vdev_stat_t *vs = &vd->vdev_stat; 596 boolean_t was_allocatable; 597 boolean_t was_initialized; 598 599 ASSERT(vd == vd->vdev_top); 600 601 mutex_enter(&mg->mg_lock); 602 was_allocatable = mg->mg_allocatable; 603 was_initialized = mg->mg_initialized; 604 605 mg->mg_free_capacity = ((vs->vs_space - vs->vs_alloc) * 100) / 606 (vs->vs_space + 1); 607 608 mutex_enter(&mc->mc_lock); 609 610 /* 611 * If the metaslab group was just added then it won't 612 * have any space until we finish syncing out this txg. 613 * At that point we will consider it initialized and available 614 * for allocations. We also don't consider non-activated 615 * metaslab groups (e.g. vdevs that are in the middle of being removed) 616 * to be initialized, because they can't be used for allocation. 617 */ 618 mg->mg_initialized = metaslab_group_initialized(mg); 619 if (!was_initialized && mg->mg_initialized) { 620 mc->mc_groups++; 621 } else if (was_initialized && !mg->mg_initialized) { 622 ASSERT3U(mc->mc_groups, >, 0); 623 mc->mc_groups--; 624 } 625 if (mg->mg_initialized) 626 mg->mg_no_free_space = B_FALSE; 627 628 /* 629 * A metaslab group is considered allocatable if it has plenty 630 * of free space or is not heavily fragmented. We only take 631 * fragmentation into account if the metaslab group has a valid 632 * fragmentation metric (i.e. a value between 0 and 100). 633 */ 634 mg->mg_allocatable = (mg->mg_activation_count > 0 && 635 mg->mg_free_capacity > zfs_mg_noalloc_threshold && 636 (mg->mg_fragmentation == ZFS_FRAG_INVALID || 637 mg->mg_fragmentation <= zfs_mg_fragmentation_threshold)); 638 639 /* 640 * The mc_alloc_groups maintains a count of the number of 641 * groups in this metaslab class that are still above the 642 * zfs_mg_noalloc_threshold. This is used by the allocating 643 * threads to determine if they should avoid allocations to 644 * a given group. The allocator will avoid allocations to a group 645 * if that group has reached or is below the zfs_mg_noalloc_threshold 646 * and there are still other groups that are above the threshold. 647 * When a group transitions from allocatable to non-allocatable or 648 * vice versa we update the metaslab class to reflect that change. 649 * When the mc_alloc_groups value drops to 0 that means that all 650 * groups have reached the zfs_mg_noalloc_threshold making all groups 651 * eligible for allocations. This effectively means that all devices 652 * are balanced again. 653 */ 654 if (was_allocatable && !mg->mg_allocatable) 655 mc->mc_alloc_groups--; 656 else if (!was_allocatable && mg->mg_allocatable) 657 mc->mc_alloc_groups++; 658 mutex_exit(&mc->mc_lock); 659 660 mutex_exit(&mg->mg_lock); 661} 662 663metaslab_group_t * 664metaslab_group_create(metaslab_class_t *mc, vdev_t *vd) 665{ 666 metaslab_group_t *mg; 667 668 mg = kmem_zalloc(sizeof (metaslab_group_t), KM_SLEEP); 669 mutex_init(&mg->mg_lock, NULL, MUTEX_DEFAULT, NULL); 670 avl_create(&mg->mg_metaslab_tree, metaslab_compare, 671 sizeof (metaslab_t), offsetof(struct metaslab, ms_group_node)); 672 mg->mg_vd = vd; 673 mg->mg_class = mc; 674 mg->mg_activation_count = 0; 675 mg->mg_initialized = B_FALSE; 676 mg->mg_no_free_space = B_TRUE; 677 refcount_create_tracked(&mg->mg_alloc_queue_depth); 678 679 mg->mg_taskq = taskq_create("metaslab_group_taskq", metaslab_load_pct, 680 minclsyspri, 10, INT_MAX, TASKQ_THREADS_CPU_PCT); 681 682 return (mg); 683} 684 685void 686metaslab_group_destroy(metaslab_group_t *mg) 687{ 688 ASSERT(mg->mg_prev == NULL); 689 ASSERT(mg->mg_next == NULL); 690 /* 691 * We may have gone below zero with the activation count 692 * either because we never activated in the first place or 693 * because we're done, and possibly removing the vdev. 694 */ 695 ASSERT(mg->mg_activation_count <= 0); 696 697 taskq_destroy(mg->mg_taskq); 698 avl_destroy(&mg->mg_metaslab_tree); 699 mutex_destroy(&mg->mg_lock); 700 refcount_destroy(&mg->mg_alloc_queue_depth); 701 kmem_free(mg, sizeof (metaslab_group_t)); 702} 703 704void 705metaslab_group_activate(metaslab_group_t *mg) 706{ 707 metaslab_class_t *mc = mg->mg_class; 708 metaslab_group_t *mgprev, *mgnext; 709 710 ASSERT(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_WRITER)); 711 712 ASSERT(mc->mc_rotor != mg); 713 ASSERT(mg->mg_prev == NULL); 714 ASSERT(mg->mg_next == NULL); 715 ASSERT(mg->mg_activation_count <= 0); 716 717 if (++mg->mg_activation_count <= 0) 718 return; 719 720 mg->mg_aliquot = metaslab_aliquot * MAX(1, mg->mg_vd->vdev_children); 721 metaslab_group_alloc_update(mg); 722 723 if ((mgprev = mc->mc_rotor) == NULL) { 724 mg->mg_prev = mg; 725 mg->mg_next = mg; 726 } else { 727 mgnext = mgprev->mg_next; 728 mg->mg_prev = mgprev; 729 mg->mg_next = mgnext; 730 mgprev->mg_next = mg; 731 mgnext->mg_prev = mg; 732 } 733 mc->mc_rotor = mg; 734 metaslab_class_minblocksize_update(mc); 735} 736 737void 738metaslab_group_passivate(metaslab_group_t *mg) 739{ 740 metaslab_class_t *mc = mg->mg_class; 741 metaslab_group_t *mgprev, *mgnext; 742 743 ASSERT(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_WRITER)); 744 745 if (--mg->mg_activation_count != 0) { 746 ASSERT(mc->mc_rotor != mg); 747 ASSERT(mg->mg_prev == NULL); 748 ASSERT(mg->mg_next == NULL); 749 ASSERT(mg->mg_activation_count < 0); 750 return; 751 } 752 753 taskq_wait(mg->mg_taskq); 754 metaslab_group_alloc_update(mg); 755 756 mgprev = mg->mg_prev; 757 mgnext = mg->mg_next; 758 759 if (mg == mgnext) { 760 mc->mc_rotor = NULL; 761 } else { 762 mc->mc_rotor = mgnext; 763 mgprev->mg_next = mgnext; 764 mgnext->mg_prev = mgprev; 765 } 766 767 mg->mg_prev = NULL; 768 mg->mg_next = NULL; 769 metaslab_class_minblocksize_update(mc); 770} 771 772boolean_t 773metaslab_group_initialized(metaslab_group_t *mg) 774{ 775 vdev_t *vd = mg->mg_vd; 776 vdev_stat_t *vs = &vd->vdev_stat; 777 778 return (vs->vs_space != 0 && mg->mg_activation_count > 0); 779} 780 781uint64_t 782metaslab_group_get_space(metaslab_group_t *mg) 783{ 784 return ((1ULL << mg->mg_vd->vdev_ms_shift) * mg->mg_vd->vdev_ms_count); 785} 786 787void 788metaslab_group_histogram_verify(metaslab_group_t *mg) 789{ 790 uint64_t *mg_hist; 791 vdev_t *vd = mg->mg_vd; 792 uint64_t ashift = vd->vdev_ashift; 793 int i; 794 795 if ((zfs_flags & ZFS_DEBUG_HISTOGRAM_VERIFY) == 0) 796 return; 797 798 mg_hist = kmem_zalloc(sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE, 799 KM_SLEEP); 800 801 ASSERT3U(RANGE_TREE_HISTOGRAM_SIZE, >=, 802 SPACE_MAP_HISTOGRAM_SIZE + ashift); 803 804 for (int m = 0; m < vd->vdev_ms_count; m++) { 805 metaslab_t *msp = vd->vdev_ms[m]; 806 807 if (msp->ms_sm == NULL) 808 continue; 809 810 for (i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++) 811 mg_hist[i + ashift] += 812 msp->ms_sm->sm_phys->smp_histogram[i]; 813 } 814 815 for (i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i ++) 816 VERIFY3U(mg_hist[i], ==, mg->mg_histogram[i]); 817 818 kmem_free(mg_hist, sizeof (uint64_t) * RANGE_TREE_HISTOGRAM_SIZE); 819} 820 821static void 822metaslab_group_histogram_add(metaslab_group_t *mg, metaslab_t *msp) 823{ 824 metaslab_class_t *mc = mg->mg_class; 825 uint64_t ashift = mg->mg_vd->vdev_ashift; 826 827 ASSERT(MUTEX_HELD(&msp->ms_lock)); 828 if (msp->ms_sm == NULL) 829 return; 830 831 mutex_enter(&mg->mg_lock); 832 for (int i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++) { 833 mg->mg_histogram[i + ashift] += 834 msp->ms_sm->sm_phys->smp_histogram[i]; 835 mc->mc_histogram[i + ashift] += 836 msp->ms_sm->sm_phys->smp_histogram[i]; 837 } 838 mutex_exit(&mg->mg_lock); 839} 840 841void 842metaslab_group_histogram_remove(metaslab_group_t *mg, metaslab_t *msp) 843{ 844 metaslab_class_t *mc = mg->mg_class; 845 uint64_t ashift = mg->mg_vd->vdev_ashift; 846 847 ASSERT(MUTEX_HELD(&msp->ms_lock)); 848 if (msp->ms_sm == NULL) 849 return; 850 851 mutex_enter(&mg->mg_lock); 852 for (int i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++) { 853 ASSERT3U(mg->mg_histogram[i + ashift], >=, 854 msp->ms_sm->sm_phys->smp_histogram[i]); 855 ASSERT3U(mc->mc_histogram[i + ashift], >=, 856 msp->ms_sm->sm_phys->smp_histogram[i]); 857 858 mg->mg_histogram[i + ashift] -= 859 msp->ms_sm->sm_phys->smp_histogram[i]; 860 mc->mc_histogram[i + ashift] -= 861 msp->ms_sm->sm_phys->smp_histogram[i]; 862 } 863 mutex_exit(&mg->mg_lock); 864} 865 866static void 867metaslab_group_add(metaslab_group_t *mg, metaslab_t *msp) 868{ 869 ASSERT(msp->ms_group == NULL); 870 mutex_enter(&mg->mg_lock); 871 msp->ms_group = mg; 872 msp->ms_weight = 0; 873 avl_add(&mg->mg_metaslab_tree, msp); 874 mutex_exit(&mg->mg_lock); 875 876 mutex_enter(&msp->ms_lock); 877 metaslab_group_histogram_add(mg, msp); 878 mutex_exit(&msp->ms_lock); 879} 880 881static void 882metaslab_group_remove(metaslab_group_t *mg, metaslab_t *msp) 883{ 884 mutex_enter(&msp->ms_lock); 885 metaslab_group_histogram_remove(mg, msp); 886 mutex_exit(&msp->ms_lock); 887 888 mutex_enter(&mg->mg_lock); 889 ASSERT(msp->ms_group == mg); 890 avl_remove(&mg->mg_metaslab_tree, msp); 891 msp->ms_group = NULL; 892 mutex_exit(&mg->mg_lock); 893} 894 895static void 896metaslab_group_sort(metaslab_group_t *mg, metaslab_t *msp, uint64_t weight) 897{ 898 /* 899 * Although in principle the weight can be any value, in 900 * practice we do not use values in the range [1, 511]. 901 */ 902 ASSERT(weight >= SPA_MINBLOCKSIZE || weight == 0); 903 ASSERT(MUTEX_HELD(&msp->ms_lock)); 904 905 mutex_enter(&mg->mg_lock); 906 ASSERT(msp->ms_group == mg); 907 avl_remove(&mg->mg_metaslab_tree, msp); 908 msp->ms_weight = weight; 909 avl_add(&mg->mg_metaslab_tree, msp); 910 mutex_exit(&mg->mg_lock); 911} 912 913/* 914 * Calculate the fragmentation for a given metaslab group. We can use 915 * a simple average here since all metaslabs within the group must have 916 * the same size. The return value will be a value between 0 and 100 917 * (inclusive), or ZFS_FRAG_INVALID if less than half of the metaslab in this 918 * group have a fragmentation metric. 919 */ 920uint64_t 921metaslab_group_fragmentation(metaslab_group_t *mg) 922{ 923 vdev_t *vd = mg->mg_vd; 924 uint64_t fragmentation = 0; 925 uint64_t valid_ms = 0; 926 927 for (int m = 0; m < vd->vdev_ms_count; m++) { 928 metaslab_t *msp = vd->vdev_ms[m]; 929 930 if (msp->ms_fragmentation == ZFS_FRAG_INVALID) 931 continue; 932 933 valid_ms++; 934 fragmentation += msp->ms_fragmentation; 935 } 936 937 if (valid_ms <= vd->vdev_ms_count / 2) 938 return (ZFS_FRAG_INVALID); 939 940 fragmentation /= valid_ms; 941 ASSERT3U(fragmentation, <=, 100); 942 return (fragmentation); 943} 944 945/* 946 * Determine if a given metaslab group should skip allocations. A metaslab 947 * group should avoid allocations if its free capacity is less than the 948 * zfs_mg_noalloc_threshold or its fragmentation metric is greater than 949 * zfs_mg_fragmentation_threshold and there is at least one metaslab group 950 * that can still handle allocations. If the allocation throttle is enabled 951 * then we skip allocations to devices that have reached their maximum 952 * allocation queue depth unless the selected metaslab group is the only 953 * eligible group remaining. 954 */ 955static boolean_t 956metaslab_group_allocatable(metaslab_group_t *mg, metaslab_group_t *rotor, 957 uint64_t psize) 958{ 959 spa_t *spa = mg->mg_vd->vdev_spa; 960 metaslab_class_t *mc = mg->mg_class; 961 962 /* 963 * We can only consider skipping this metaslab group if it's 964 * in the normal metaslab class and there are other metaslab 965 * groups to select from. Otherwise, we always consider it eligible 966 * for allocations. 967 */ 968 if (mc != spa_normal_class(spa) || mc->mc_groups <= 1) 969 return (B_TRUE); 970 971 /* 972 * If the metaslab group's mg_allocatable flag is set (see comments 973 * in metaslab_group_alloc_update() for more information) and 974 * the allocation throttle is disabled then allow allocations to this 975 * device. However, if the allocation throttle is enabled then 976 * check if we have reached our allocation limit (mg_alloc_queue_depth) 977 * to determine if we should allow allocations to this metaslab group. 978 * If all metaslab groups are no longer considered allocatable 979 * (mc_alloc_groups == 0) or we're trying to allocate the smallest 980 * gang block size then we allow allocations on this metaslab group 981 * regardless of the mg_allocatable or throttle settings. 982 */ 983 if (mg->mg_allocatable) { 984 metaslab_group_t *mgp; 985 int64_t qdepth; 986 uint64_t qmax = mg->mg_max_alloc_queue_depth; 987 988 if (!mc->mc_alloc_throttle_enabled) 989 return (B_TRUE); 990 991 /* 992 * If this metaslab group does not have any free space, then 993 * there is no point in looking further. 994 */ 995 if (mg->mg_no_free_space) 996 return (B_FALSE); 997 998 qdepth = refcount_count(&mg->mg_alloc_queue_depth); 999 1000 /* 1001 * If this metaslab group is below its qmax or it's 1002 * the only allocatable metasable group, then attempt 1003 * to allocate from it. 1004 */ 1005 if (qdepth < qmax || mc->mc_alloc_groups == 1) 1006 return (B_TRUE); 1007 ASSERT3U(mc->mc_alloc_groups, >, 1); 1008 1009 /* 1010 * Since this metaslab group is at or over its qmax, we 1011 * need to determine if there are metaslab groups after this 1012 * one that might be able to handle this allocation. This is 1013 * racy since we can't hold the locks for all metaslab 1014 * groups at the same time when we make this check. 1015 */ 1016 for (mgp = mg->mg_next; mgp != rotor; mgp = mgp->mg_next) { 1017 qmax = mgp->mg_max_alloc_queue_depth; 1018 1019 qdepth = refcount_count(&mgp->mg_alloc_queue_depth); 1020 1021 /* 1022 * If there is another metaslab group that 1023 * might be able to handle the allocation, then 1024 * we return false so that we skip this group. 1025 */ 1026 if (qdepth < qmax && !mgp->mg_no_free_space) 1027 return (B_FALSE); 1028 } 1029 1030 /* 1031 * We didn't find another group to handle the allocation 1032 * so we can't skip this metaslab group even though 1033 * we are at or over our qmax. 1034 */ 1035 return (B_TRUE); 1036 1037 } else if (mc->mc_alloc_groups == 0 || psize == SPA_MINBLOCKSIZE) { 1038 return (B_TRUE); 1039 } 1040 return (B_FALSE); 1041} 1042 1043/* 1044 * ========================================================================== 1045 * Range tree callbacks 1046 * ========================================================================== 1047 */ 1048 1049/* 1050 * Comparison function for the private size-ordered tree. Tree is sorted 1051 * by size, larger sizes at the end of the tree. 1052 */ 1053static int 1054metaslab_rangesize_compare(const void *x1, const void *x2) 1055{ 1056 const range_seg_t *r1 = x1; 1057 const range_seg_t *r2 = x2; 1058 uint64_t rs_size1 = r1->rs_end - r1->rs_start; 1059 uint64_t rs_size2 = r2->rs_end - r2->rs_start; 1060 1061 if (rs_size1 < rs_size2) 1062 return (-1); 1063 if (rs_size1 > rs_size2) 1064 return (1); 1065 1066 if (r1->rs_start < r2->rs_start) 1067 return (-1); 1068 1069 if (r1->rs_start > r2->rs_start) 1070 return (1); 1071 1072 return (0); 1073} 1074 1075/* 1076 * Create any block allocator specific components. The current allocators 1077 * rely on using both a size-ordered range_tree_t and an array of uint64_t's. 1078 */ 1079static void 1080metaslab_rt_create(range_tree_t *rt, void *arg) 1081{ 1082 metaslab_t *msp = arg; 1083 1084 ASSERT3P(rt->rt_arg, ==, msp); 1085 ASSERT(msp->ms_tree == NULL); 1086 1087 avl_create(&msp->ms_size_tree, metaslab_rangesize_compare, 1088 sizeof (range_seg_t), offsetof(range_seg_t, rs_pp_node)); 1089} 1090 1091/* 1092 * Destroy the block allocator specific components. 1093 */ 1094static void 1095metaslab_rt_destroy(range_tree_t *rt, void *arg) 1096{ 1097 metaslab_t *msp = arg; 1098 1099 ASSERT3P(rt->rt_arg, ==, msp); 1100 ASSERT3P(msp->ms_tree, ==, rt); 1101 ASSERT0(avl_numnodes(&msp->ms_size_tree)); 1102 1103 avl_destroy(&msp->ms_size_tree); 1104} 1105 1106static void 1107metaslab_rt_add(range_tree_t *rt, range_seg_t *rs, void *arg) 1108{ 1109 metaslab_t *msp = arg; 1110 1111 ASSERT3P(rt->rt_arg, ==, msp); 1112 ASSERT3P(msp->ms_tree, ==, rt); 1113 VERIFY(!msp->ms_condensing); 1114 avl_add(&msp->ms_size_tree, rs); 1115} 1116 1117static void 1118metaslab_rt_remove(range_tree_t *rt, range_seg_t *rs, void *arg) 1119{ 1120 metaslab_t *msp = arg; 1121 1122 ASSERT3P(rt->rt_arg, ==, msp); 1123 ASSERT3P(msp->ms_tree, ==, rt); 1124 VERIFY(!msp->ms_condensing); 1125 avl_remove(&msp->ms_size_tree, rs); 1126} 1127 1128static void 1129metaslab_rt_vacate(range_tree_t *rt, void *arg) 1130{ 1131 metaslab_t *msp = arg; 1132 1133 ASSERT3P(rt->rt_arg, ==, msp); 1134 ASSERT3P(msp->ms_tree, ==, rt); 1135 1136 /* 1137 * Normally one would walk the tree freeing nodes along the way. 1138 * Since the nodes are shared with the range trees we can avoid 1139 * walking all nodes and just reinitialize the avl tree. The nodes 1140 * will be freed by the range tree, so we don't want to free them here. 1141 */ 1142 avl_create(&msp->ms_size_tree, metaslab_rangesize_compare, 1143 sizeof (range_seg_t), offsetof(range_seg_t, rs_pp_node)); 1144} 1145 1146static range_tree_ops_t metaslab_rt_ops = { 1147 metaslab_rt_create, 1148 metaslab_rt_destroy, 1149 metaslab_rt_add, 1150 metaslab_rt_remove, 1151 metaslab_rt_vacate 1152}; 1153 1154/* 1155 * ========================================================================== 1156 * Common allocator routines 1157 * ========================================================================== 1158 */ 1159 1160/* 1161 * Return the maximum contiguous segment within the metaslab. 1162 */ 1163uint64_t 1164metaslab_block_maxsize(metaslab_t *msp) 1165{ 1166 avl_tree_t *t = &msp->ms_size_tree; 1167 range_seg_t *rs; 1168 1169 if (t == NULL || (rs = avl_last(t)) == NULL) 1170 return (0ULL); 1171 1172 return (rs->rs_end - rs->rs_start); 1173} 1174 1175static range_seg_t * 1176metaslab_block_find(avl_tree_t *t, uint64_t start, uint64_t size) 1177{ 1178 range_seg_t *rs, rsearch; 1179 avl_index_t where; 1180 1181 rsearch.rs_start = start; 1182 rsearch.rs_end = start + size; 1183 1184 rs = avl_find(t, &rsearch, &where); 1185 if (rs == NULL) { 1186 rs = avl_nearest(t, where, AVL_AFTER); 1187 } 1188 1189 return (rs); 1190} 1191 1192/* 1193 * This is a helper function that can be used by the allocator to find 1194 * a suitable block to allocate. This will search the specified AVL 1195 * tree looking for a block that matches the specified criteria. 1196 */ 1197static uint64_t 1198metaslab_block_picker(avl_tree_t *t, uint64_t *cursor, uint64_t size, 1199 uint64_t align) 1200{ 1201 range_seg_t *rs = metaslab_block_find(t, *cursor, size); 1202 1203 while (rs != NULL) { 1204 uint64_t offset = P2ROUNDUP(rs->rs_start, align); 1205 1206 if (offset + size <= rs->rs_end) { 1207 *cursor = offset + size; 1208 return (offset); 1209 } 1210 rs = AVL_NEXT(t, rs); 1211 } 1212 1213 /* 1214 * If we know we've searched the whole map (*cursor == 0), give up. 1215 * Otherwise, reset the cursor to the beginning and try again. 1216 */ 1217 if (*cursor == 0) 1218 return (-1ULL); 1219 1220 *cursor = 0; 1221 return (metaslab_block_picker(t, cursor, size, align)); 1222} 1223 1224/* 1225 * ========================================================================== 1226 * The first-fit block allocator 1227 * ========================================================================== 1228 */ 1229static uint64_t 1230metaslab_ff_alloc(metaslab_t *msp, uint64_t size) 1231{ 1232 /* 1233 * Find the largest power of 2 block size that evenly divides the 1234 * requested size. This is used to try to allocate blocks with similar 1235 * alignment from the same area of the metaslab (i.e. same cursor 1236 * bucket) but it does not guarantee that other allocations sizes 1237 * may exist in the same region. 1238 */ 1239 uint64_t align = size & -size; 1240 uint64_t *cursor = &msp->ms_lbas[highbit64(align) - 1]; 1241 avl_tree_t *t = &msp->ms_tree->rt_root; 1242 1243 return (metaslab_block_picker(t, cursor, size, align)); 1244} 1245 1246static metaslab_ops_t metaslab_ff_ops = { 1247 metaslab_ff_alloc 1248}; 1249 1250/* 1251 * ========================================================================== 1252 * Dynamic block allocator - 1253 * Uses the first fit allocation scheme until space get low and then 1254 * adjusts to a best fit allocation method. Uses metaslab_df_alloc_threshold 1255 * and metaslab_df_free_pct to determine when to switch the allocation scheme. 1256 * ========================================================================== 1257 */ 1258static uint64_t 1259metaslab_df_alloc(metaslab_t *msp, uint64_t size) 1260{ 1261 /* 1262 * Find the largest power of 2 block size that evenly divides the 1263 * requested size. This is used to try to allocate blocks with similar 1264 * alignment from the same area of the metaslab (i.e. same cursor 1265 * bucket) but it does not guarantee that other allocations sizes 1266 * may exist in the same region. 1267 */ 1268 uint64_t align = size & -size; 1269 uint64_t *cursor = &msp->ms_lbas[highbit64(align) - 1]; 1270 range_tree_t *rt = msp->ms_tree; 1271 avl_tree_t *t = &rt->rt_root; 1272 uint64_t max_size = metaslab_block_maxsize(msp); 1273 int free_pct = range_tree_space(rt) * 100 / msp->ms_size; 1274 1275 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1276 ASSERT3U(avl_numnodes(t), ==, avl_numnodes(&msp->ms_size_tree)); 1277 1278 if (max_size < size) 1279 return (-1ULL); 1280 1281 /* 1282 * If we're running low on space switch to using the size 1283 * sorted AVL tree (best-fit). 1284 */ 1285 if (max_size < metaslab_df_alloc_threshold || 1286 free_pct < metaslab_df_free_pct) { 1287 t = &msp->ms_size_tree; 1288 *cursor = 0; 1289 } 1290 1291 return (metaslab_block_picker(t, cursor, size, 1ULL)); 1292} 1293 1294static metaslab_ops_t metaslab_df_ops = { 1295 metaslab_df_alloc 1296}; 1297 1298/* 1299 * ========================================================================== 1300 * Cursor fit block allocator - 1301 * Select the largest region in the metaslab, set the cursor to the beginning 1302 * of the range and the cursor_end to the end of the range. As allocations 1303 * are made advance the cursor. Continue allocating from the cursor until 1304 * the range is exhausted and then find a new range. 1305 * ========================================================================== 1306 */ 1307static uint64_t 1308metaslab_cf_alloc(metaslab_t *msp, uint64_t size) 1309{ 1310 range_tree_t *rt = msp->ms_tree; 1311 avl_tree_t *t = &msp->ms_size_tree; 1312 uint64_t *cursor = &msp->ms_lbas[0]; 1313 uint64_t *cursor_end = &msp->ms_lbas[1]; 1314 uint64_t offset = 0; 1315 1316 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1317 ASSERT3U(avl_numnodes(t), ==, avl_numnodes(&rt->rt_root)); 1318 1319 ASSERT3U(*cursor_end, >=, *cursor); 1320 1321 if ((*cursor + size) > *cursor_end) { 1322 range_seg_t *rs; 1323 1324 rs = avl_last(&msp->ms_size_tree); 1325 if (rs == NULL || (rs->rs_end - rs->rs_start) < size) 1326 return (-1ULL); 1327 1328 *cursor = rs->rs_start; 1329 *cursor_end = rs->rs_end; 1330 } 1331 1332 offset = *cursor; 1333 *cursor += size; 1334 1335 return (offset); 1336} 1337 1338static metaslab_ops_t metaslab_cf_ops = { 1339 metaslab_cf_alloc 1340}; 1341 1342/* 1343 * ========================================================================== 1344 * New dynamic fit allocator - 1345 * Select a region that is large enough to allocate 2^metaslab_ndf_clump_shift 1346 * contiguous blocks. If no region is found then just use the largest segment 1347 * that remains. 1348 * ========================================================================== 1349 */ 1350 1351/* 1352 * Determines desired number of contiguous blocks (2^metaslab_ndf_clump_shift) 1353 * to request from the allocator. 1354 */ 1355uint64_t metaslab_ndf_clump_shift = 4; 1356 1357static uint64_t 1358metaslab_ndf_alloc(metaslab_t *msp, uint64_t size) 1359{ 1360 avl_tree_t *t = &msp->ms_tree->rt_root; 1361 avl_index_t where; 1362 range_seg_t *rs, rsearch; 1363 uint64_t hbit = highbit64(size); 1364 uint64_t *cursor = &msp->ms_lbas[hbit - 1]; 1365 uint64_t max_size = metaslab_block_maxsize(msp); 1366 1367 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1368 ASSERT3U(avl_numnodes(t), ==, avl_numnodes(&msp->ms_size_tree)); 1369 1370 if (max_size < size) 1371 return (-1ULL); 1372 1373 rsearch.rs_start = *cursor; 1374 rsearch.rs_end = *cursor + size; 1375 1376 rs = avl_find(t, &rsearch, &where); 1377 if (rs == NULL || (rs->rs_end - rs->rs_start) < size) { 1378 t = &msp->ms_size_tree; 1379 1380 rsearch.rs_start = 0; 1381 rsearch.rs_end = MIN(max_size, 1382 1ULL << (hbit + metaslab_ndf_clump_shift)); 1383 rs = avl_find(t, &rsearch, &where); 1384 if (rs == NULL) 1385 rs = avl_nearest(t, where, AVL_AFTER); 1386 ASSERT(rs != NULL); 1387 } 1388 1389 if ((rs->rs_end - rs->rs_start) >= size) { 1390 *cursor = rs->rs_start + size; 1391 return (rs->rs_start); 1392 } 1393 return (-1ULL); 1394} 1395 1396static metaslab_ops_t metaslab_ndf_ops = { 1397 metaslab_ndf_alloc 1398}; 1399 1400metaslab_ops_t *zfs_metaslab_ops = &metaslab_df_ops; 1401 1402/* 1403 * ========================================================================== 1404 * Metaslabs 1405 * ========================================================================== 1406 */ 1407 1408/* 1409 * Wait for any in-progress metaslab loads to complete. 1410 */ 1411void 1412metaslab_load_wait(metaslab_t *msp) 1413{ 1414 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1415 1416 while (msp->ms_loading) { 1417 ASSERT(!msp->ms_loaded); 1418 cv_wait(&msp->ms_load_cv, &msp->ms_lock); 1419 } 1420} 1421 1422int 1423metaslab_load(metaslab_t *msp) 1424{ 1425 int error = 0; 1426 boolean_t success = B_FALSE; 1427 1428 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1429 ASSERT(!msp->ms_loaded); 1430 ASSERT(!msp->ms_loading); 1431 1432 msp->ms_loading = B_TRUE; 1433 1434 /* 1435 * If the space map has not been allocated yet, then treat 1436 * all the space in the metaslab as free and add it to the 1437 * ms_tree. 1438 */ 1439 if (msp->ms_sm != NULL) 1440 error = space_map_load(msp->ms_sm, msp->ms_tree, SM_FREE); 1441 else 1442 range_tree_add(msp->ms_tree, msp->ms_start, msp->ms_size); 1443 1444 success = (error == 0); 1445 msp->ms_loading = B_FALSE; 1446 1447 if (success) { 1448 ASSERT3P(msp->ms_group, !=, NULL); 1449 msp->ms_loaded = B_TRUE; 1450 1451 for (int t = 0; t < TXG_DEFER_SIZE; t++) { 1452 range_tree_walk(msp->ms_defertree[t], 1453 range_tree_remove, msp->ms_tree); 1454 } 1455 msp->ms_max_size = metaslab_block_maxsize(msp); 1456 } 1457 cv_broadcast(&msp->ms_load_cv); 1458 return (error); 1459} 1460 1461void 1462metaslab_unload(metaslab_t *msp) 1463{ 1464 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1465 range_tree_vacate(msp->ms_tree, NULL, NULL); 1466 msp->ms_loaded = B_FALSE; 1467 msp->ms_weight &= ~METASLAB_ACTIVE_MASK; 1468 msp->ms_max_size = 0; 1469} 1470 1471int 1472metaslab_init(metaslab_group_t *mg, uint64_t id, uint64_t object, uint64_t txg, 1473 metaslab_t **msp) 1474{ 1475 vdev_t *vd = mg->mg_vd; 1476 objset_t *mos = vd->vdev_spa->spa_meta_objset; 1477 metaslab_t *ms; 1478 int error; 1479 1480 ms = kmem_zalloc(sizeof (metaslab_t), KM_SLEEP); 1481 mutex_init(&ms->ms_lock, NULL, MUTEX_DEFAULT, NULL); 1482 cv_init(&ms->ms_load_cv, NULL, CV_DEFAULT, NULL); 1483 ms->ms_id = id; 1484 ms->ms_start = id << vd->vdev_ms_shift; 1485 ms->ms_size = 1ULL << vd->vdev_ms_shift; 1486 1487 /* 1488 * We only open space map objects that already exist. All others 1489 * will be opened when we finally allocate an object for it. 1490 */ 1491 if (object != 0) { 1492 error = space_map_open(&ms->ms_sm, mos, object, ms->ms_start, 1493 ms->ms_size, vd->vdev_ashift, &ms->ms_lock); 1494 1495 if (error != 0) { 1496 kmem_free(ms, sizeof (metaslab_t)); 1497 return (error); 1498 } 1499 1500 ASSERT(ms->ms_sm != NULL); 1501 } 1502 1503 /* 1504 * We create the main range tree here, but we don't create the 1505 * other range trees until metaslab_sync_done(). This serves 1506 * two purposes: it allows metaslab_sync_done() to detect the 1507 * addition of new space; and for debugging, it ensures that we'd 1508 * data fault on any attempt to use this metaslab before it's ready. 1509 */ 1510 ms->ms_tree = range_tree_create(&metaslab_rt_ops, ms, &ms->ms_lock); 1511 metaslab_group_add(mg, ms); 1512 1513 metaslab_set_fragmentation(ms); 1514 1515 /* 1516 * If we're opening an existing pool (txg == 0) or creating 1517 * a new one (txg == TXG_INITIAL), all space is available now. 1518 * If we're adding space to an existing pool, the new space 1519 * does not become available until after this txg has synced. 1520 * The metaslab's weight will also be initialized when we sync 1521 * out this txg. This ensures that we don't attempt to allocate 1522 * from it before we have initialized it completely. 1523 */ 1524 if (txg <= TXG_INITIAL) 1525 metaslab_sync_done(ms, 0); 1526 1527 /* 1528 * If metaslab_debug_load is set and we're initializing a metaslab 1529 * that has an allocated space map object then load the its space 1530 * map so that can verify frees. 1531 */ 1532 if (metaslab_debug_load && ms->ms_sm != NULL) { 1533 mutex_enter(&ms->ms_lock); 1534 VERIFY0(metaslab_load(ms)); 1535 mutex_exit(&ms->ms_lock); 1536 } 1537 1538 if (txg != 0) { 1539 vdev_dirty(vd, 0, NULL, txg); 1540 vdev_dirty(vd, VDD_METASLAB, ms, txg); 1541 } 1542 1543 *msp = ms; 1544 1545 return (0); 1546} 1547 1548void 1549metaslab_fini(metaslab_t *msp) 1550{ 1551 metaslab_group_t *mg = msp->ms_group; 1552 1553 metaslab_group_remove(mg, msp); 1554 1555 mutex_enter(&msp->ms_lock); 1556 VERIFY(msp->ms_group == NULL); 1557 vdev_space_update(mg->mg_vd, -space_map_allocated(msp->ms_sm), 1558 0, -msp->ms_size); 1559 space_map_close(msp->ms_sm); 1560 1561 metaslab_unload(msp); 1562 range_tree_destroy(msp->ms_tree); 1563 range_tree_destroy(msp->ms_freeingtree); 1564 range_tree_destroy(msp->ms_freedtree); 1565 1566 for (int t = 0; t < TXG_SIZE; t++) { 1567 range_tree_destroy(msp->ms_alloctree[t]); 1568 } 1569 1570 for (int t = 0; t < TXG_DEFER_SIZE; t++) { 1571 range_tree_destroy(msp->ms_defertree[t]); 1572 } 1573 1574 ASSERT0(msp->ms_deferspace); 1575 1576 mutex_exit(&msp->ms_lock); 1577 cv_destroy(&msp->ms_load_cv); 1578 mutex_destroy(&msp->ms_lock); 1579 1580 kmem_free(msp, sizeof (metaslab_t)); 1581} 1582 1583#define FRAGMENTATION_TABLE_SIZE 17 1584 1585/* 1586 * This table defines a segment size based fragmentation metric that will 1587 * allow each metaslab to derive its own fragmentation value. This is done 1588 * by calculating the space in each bucket of the spacemap histogram and 1589 * multiplying that by the fragmetation metric in this table. Doing 1590 * this for all buckets and dividing it by the total amount of free 1591 * space in this metaslab (i.e. the total free space in all buckets) gives 1592 * us the fragmentation metric. This means that a high fragmentation metric 1593 * equates to most of the free space being comprised of small segments. 1594 * Conversely, if the metric is low, then most of the free space is in 1595 * large segments. A 10% change in fragmentation equates to approximately 1596 * double the number of segments. 1597 * 1598 * This table defines 0% fragmented space using 16MB segments. Testing has 1599 * shown that segments that are greater than or equal to 16MB do not suffer 1600 * from drastic performance problems. Using this value, we derive the rest 1601 * of the table. Since the fragmentation value is never stored on disk, it 1602 * is possible to change these calculations in the future. 1603 */ 1604int zfs_frag_table[FRAGMENTATION_TABLE_SIZE] = { 1605 100, /* 512B */ 1606 100, /* 1K */ 1607 98, /* 2K */ 1608 95, /* 4K */ 1609 90, /* 8K */ 1610 80, /* 16K */ 1611 70, /* 32K */ 1612 60, /* 64K */ 1613 50, /* 128K */ 1614 40, /* 256K */ 1615 30, /* 512K */ 1616 20, /* 1M */ 1617 15, /* 2M */ 1618 10, /* 4M */ 1619 5, /* 8M */ 1620 0 /* 16M */ 1621}; 1622 1623/* 1624 * Calclate the metaslab's fragmentation metric. A return value 1625 * of ZFS_FRAG_INVALID means that the metaslab has not been upgraded and does 1626 * not support this metric. Otherwise, the return value should be in the 1627 * range [0, 100]. 1628 */ 1629static void 1630metaslab_set_fragmentation(metaslab_t *msp) 1631{ 1632 spa_t *spa = msp->ms_group->mg_vd->vdev_spa; 1633 uint64_t fragmentation = 0; 1634 uint64_t total = 0; 1635 boolean_t feature_enabled = spa_feature_is_enabled(spa, 1636 SPA_FEATURE_SPACEMAP_HISTOGRAM); 1637 1638 if (!feature_enabled) { 1639 msp->ms_fragmentation = ZFS_FRAG_INVALID; 1640 return; 1641 } 1642 1643 /* 1644 * A null space map means that the entire metaslab is free 1645 * and thus is not fragmented. 1646 */ 1647 if (msp->ms_sm == NULL) { 1648 msp->ms_fragmentation = 0; 1649 return; 1650 } 1651 1652 /* 1653 * If this metaslab's space map has not been upgraded, flag it 1654 * so that we upgrade next time we encounter it. 1655 */ 1656 if (msp->ms_sm->sm_dbuf->db_size != sizeof (space_map_phys_t)) { 1657 uint64_t txg = spa_syncing_txg(spa); 1658 vdev_t *vd = msp->ms_group->mg_vd; 1659 1660 /* 1661 * If we've reached the final dirty txg, then we must 1662 * be shutting down the pool. We don't want to dirty 1663 * any data past this point so skip setting the condense 1664 * flag. We can retry this action the next time the pool 1665 * is imported. 1666 */ 1667 if (spa_writeable(spa) && txg < spa_final_dirty_txg(spa)) { 1668 msp->ms_condense_wanted = B_TRUE; 1669 vdev_dirty(vd, VDD_METASLAB, msp, txg + 1); 1670 spa_dbgmsg(spa, "txg %llu, requesting force condense: " 1671 "ms_id %llu, vdev_id %llu", txg, msp->ms_id, 1672 vd->vdev_id); 1673 } 1674 msp->ms_fragmentation = ZFS_FRAG_INVALID; 1675 return; 1676 } 1677 1678 for (int i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++) { 1679 uint64_t space = 0; 1680 uint8_t shift = msp->ms_sm->sm_shift; 1681 1682 int idx = MIN(shift - SPA_MINBLOCKSHIFT + i, 1683 FRAGMENTATION_TABLE_SIZE - 1); 1684 1685 if (msp->ms_sm->sm_phys->smp_histogram[i] == 0) 1686 continue; 1687 1688 space = msp->ms_sm->sm_phys->smp_histogram[i] << (i + shift); 1689 total += space; 1690 1691 ASSERT3U(idx, <, FRAGMENTATION_TABLE_SIZE); 1692 fragmentation += space * zfs_frag_table[idx]; 1693 } 1694 1695 if (total > 0) 1696 fragmentation /= total; 1697 ASSERT3U(fragmentation, <=, 100); 1698 1699 msp->ms_fragmentation = fragmentation; 1700} 1701 1702/* 1703 * Compute a weight -- a selection preference value -- for the given metaslab. 1704 * This is based on the amount of free space, the level of fragmentation, 1705 * the LBA range, and whether the metaslab is loaded. 1706 */ 1707static uint64_t 1708metaslab_space_weight(metaslab_t *msp) 1709{ 1710 metaslab_group_t *mg = msp->ms_group; 1711 vdev_t *vd = mg->mg_vd; 1712 uint64_t weight, space; 1713 1714 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1715 ASSERT(!vd->vdev_removing); 1716 1717 /* 1718 * The baseline weight is the metaslab's free space. 1719 */ 1720 space = msp->ms_size - space_map_allocated(msp->ms_sm); 1721 1722 if (metaslab_fragmentation_factor_enabled && 1723 msp->ms_fragmentation != ZFS_FRAG_INVALID) { 1724 /* 1725 * Use the fragmentation information to inversely scale 1726 * down the baseline weight. We need to ensure that we 1727 * don't exclude this metaslab completely when it's 100% 1728 * fragmented. To avoid this we reduce the fragmented value 1729 * by 1. 1730 */ 1731 space = (space * (100 - (msp->ms_fragmentation - 1))) / 100; 1732 1733 /* 1734 * If space < SPA_MINBLOCKSIZE, then we will not allocate from 1735 * this metaslab again. The fragmentation metric may have 1736 * decreased the space to something smaller than 1737 * SPA_MINBLOCKSIZE, so reset the space to SPA_MINBLOCKSIZE 1738 * so that we can consume any remaining space. 1739 */ 1740 if (space > 0 && space < SPA_MINBLOCKSIZE) 1741 space = SPA_MINBLOCKSIZE; 1742 } 1743 weight = space; 1744 1745 /* 1746 * Modern disks have uniform bit density and constant angular velocity. 1747 * Therefore, the outer recording zones are faster (higher bandwidth) 1748 * than the inner zones by the ratio of outer to inner track diameter, 1749 * which is typically around 2:1. We account for this by assigning 1750 * higher weight to lower metaslabs (multiplier ranging from 2x to 1x). 1751 * In effect, this means that we'll select the metaslab with the most 1752 * free bandwidth rather than simply the one with the most free space. 1753 */ 1754 if (metaslab_lba_weighting_enabled) { 1755 weight = 2 * weight - (msp->ms_id * weight) / vd->vdev_ms_count; 1756 ASSERT(weight >= space && weight <= 2 * space); 1757 } 1758 1759 /* 1760 * If this metaslab is one we're actively using, adjust its 1761 * weight to make it preferable to any inactive metaslab so 1762 * we'll polish it off. If the fragmentation on this metaslab 1763 * has exceed our threshold, then don't mark it active. 1764 */ 1765 if (msp->ms_loaded && msp->ms_fragmentation != ZFS_FRAG_INVALID && 1766 msp->ms_fragmentation <= zfs_metaslab_fragmentation_threshold) { 1767 weight |= (msp->ms_weight & METASLAB_ACTIVE_MASK); 1768 } 1769 1770 WEIGHT_SET_SPACEBASED(weight); 1771 return (weight); 1772} 1773 1774/* 1775 * Return the weight of the specified metaslab, according to the segment-based 1776 * weighting algorithm. The metaslab must be loaded. This function can 1777 * be called within a sync pass since it relies only on the metaslab's 1778 * range tree which is always accurate when the metaslab is loaded. 1779 */ 1780static uint64_t 1781metaslab_weight_from_range_tree(metaslab_t *msp) 1782{ 1783 uint64_t weight = 0; 1784 uint32_t segments = 0; 1785 1786 ASSERT(msp->ms_loaded); 1787 1788 for (int i = RANGE_TREE_HISTOGRAM_SIZE - 1; i >= SPA_MINBLOCKSHIFT; 1789 i--) { 1790 uint8_t shift = msp->ms_group->mg_vd->vdev_ashift; 1791 int max_idx = SPACE_MAP_HISTOGRAM_SIZE + shift - 1; 1792 1793 segments <<= 1; 1794 segments += msp->ms_tree->rt_histogram[i]; 1795 1796 /* 1797 * The range tree provides more precision than the space map 1798 * and must be downgraded so that all values fit within the 1799 * space map's histogram. This allows us to compare loaded 1800 * vs. unloaded metaslabs to determine which metaslab is 1801 * considered "best". 1802 */ 1803 if (i > max_idx) 1804 continue; 1805 1806 if (segments != 0) { 1807 WEIGHT_SET_COUNT(weight, segments); 1808 WEIGHT_SET_INDEX(weight, i); 1809 WEIGHT_SET_ACTIVE(weight, 0); 1810 break; 1811 } 1812 } 1813 return (weight); 1814} 1815 1816/* 1817 * Calculate the weight based on the on-disk histogram. This should only 1818 * be called after a sync pass has completely finished since the on-disk 1819 * information is updated in metaslab_sync(). 1820 */ 1821static uint64_t 1822metaslab_weight_from_spacemap(metaslab_t *msp) 1823{ 1824 uint64_t weight = 0; 1825 1826 for (int i = SPACE_MAP_HISTOGRAM_SIZE - 1; i >= 0; i--) { 1827 if (msp->ms_sm->sm_phys->smp_histogram[i] != 0) { 1828 WEIGHT_SET_COUNT(weight, 1829 msp->ms_sm->sm_phys->smp_histogram[i]); 1830 WEIGHT_SET_INDEX(weight, i + 1831 msp->ms_sm->sm_shift); 1832 WEIGHT_SET_ACTIVE(weight, 0); 1833 break; 1834 } 1835 } 1836 return (weight); 1837} 1838 1839/* 1840 * Compute a segment-based weight for the specified metaslab. The weight 1841 * is determined by highest bucket in the histogram. The information 1842 * for the highest bucket is encoded into the weight value. 1843 */ 1844static uint64_t 1845metaslab_segment_weight(metaslab_t *msp) 1846{ 1847 metaslab_group_t *mg = msp->ms_group; 1848 uint64_t weight = 0; 1849 uint8_t shift = mg->mg_vd->vdev_ashift; 1850 1851 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1852 1853 /* 1854 * The metaslab is completely free. 1855 */ 1856 if (space_map_allocated(msp->ms_sm) == 0) { 1857 int idx = highbit64(msp->ms_size) - 1; 1858 int max_idx = SPACE_MAP_HISTOGRAM_SIZE + shift - 1; 1859 1860 if (idx < max_idx) { 1861 WEIGHT_SET_COUNT(weight, 1ULL); 1862 WEIGHT_SET_INDEX(weight, idx); 1863 } else { 1864 WEIGHT_SET_COUNT(weight, 1ULL << (idx - max_idx)); 1865 WEIGHT_SET_INDEX(weight, max_idx); 1866 } 1867 WEIGHT_SET_ACTIVE(weight, 0); 1868 ASSERT(!WEIGHT_IS_SPACEBASED(weight)); 1869 1870 return (weight); 1871 } 1872 1873 ASSERT3U(msp->ms_sm->sm_dbuf->db_size, ==, sizeof (space_map_phys_t)); 1874 1875 /* 1876 * If the metaslab is fully allocated then just make the weight 0. 1877 */ 1878 if (space_map_allocated(msp->ms_sm) == msp->ms_size) 1879 return (0); 1880 /* 1881 * If the metaslab is already loaded, then use the range tree to 1882 * determine the weight. Otherwise, we rely on the space map information 1883 * to generate the weight. 1884 */ 1885 if (msp->ms_loaded) { 1886 weight = metaslab_weight_from_range_tree(msp); 1887 } else { 1888 weight = metaslab_weight_from_spacemap(msp); 1889 } 1890 1891 /* 1892 * If the metaslab was active the last time we calculated its weight 1893 * then keep it active. We want to consume the entire region that 1894 * is associated with this weight. 1895 */ 1896 if (msp->ms_activation_weight != 0 && weight != 0) 1897 WEIGHT_SET_ACTIVE(weight, WEIGHT_GET_ACTIVE(msp->ms_weight)); 1898 return (weight); 1899} 1900 1901/* 1902 * Determine if we should attempt to allocate from this metaslab. If the 1903 * metaslab has a maximum size then we can quickly determine if the desired 1904 * allocation size can be satisfied. Otherwise, if we're using segment-based 1905 * weighting then we can determine the maximum allocation that this metaslab 1906 * can accommodate based on the index encoded in the weight. If we're using 1907 * space-based weights then rely on the entire weight (excluding the weight 1908 * type bit). 1909 */ 1910boolean_t 1911metaslab_should_allocate(metaslab_t *msp, uint64_t asize) 1912{ 1913 boolean_t should_allocate; 1914 1915 if (msp->ms_max_size != 0) 1916 return (msp->ms_max_size >= asize); 1917 1918 if (!WEIGHT_IS_SPACEBASED(msp->ms_weight)) { 1919 /* 1920 * The metaslab segment weight indicates segments in the 1921 * range [2^i, 2^(i+1)), where i is the index in the weight. 1922 * Since the asize might be in the middle of the range, we 1923 * should attempt the allocation if asize < 2^(i+1). 1924 */ 1925 should_allocate = (asize < 1926 1ULL << (WEIGHT_GET_INDEX(msp->ms_weight) + 1)); 1927 } else { 1928 should_allocate = (asize <= 1929 (msp->ms_weight & ~METASLAB_WEIGHT_TYPE)); 1930 } 1931 return (should_allocate); 1932} 1933 1934static uint64_t 1935metaslab_weight(metaslab_t *msp) 1936{ 1937 vdev_t *vd = msp->ms_group->mg_vd; 1938 spa_t *spa = vd->vdev_spa; 1939 uint64_t weight; 1940 1941 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1942 1943 /* 1944 * This vdev is in the process of being removed so there is nothing 1945 * for us to do here. 1946 */ 1947 if (vd->vdev_removing) { 1948 ASSERT0(space_map_allocated(msp->ms_sm)); 1949 ASSERT0(vd->vdev_ms_shift); 1950 return (0); 1951 } 1952 1953 metaslab_set_fragmentation(msp); 1954 1955 /* 1956 * Update the maximum size if the metaslab is loaded. This will 1957 * ensure that we get an accurate maximum size if newly freed space 1958 * has been added back into the free tree. 1959 */ 1960 if (msp->ms_loaded) 1961 msp->ms_max_size = metaslab_block_maxsize(msp); 1962 1963 /* 1964 * Segment-based weighting requires space map histogram support. 1965 */ 1966 if (zfs_metaslab_segment_weight_enabled && 1967 spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM) && 1968 (msp->ms_sm == NULL || msp->ms_sm->sm_dbuf->db_size == 1969 sizeof (space_map_phys_t))) { 1970 weight = metaslab_segment_weight(msp); 1971 } else { 1972 weight = metaslab_space_weight(msp); 1973 } 1974 return (weight); 1975} 1976 1977static int 1978metaslab_activate(metaslab_t *msp, uint64_t activation_weight) 1979{ 1980 ASSERT(MUTEX_HELD(&msp->ms_lock)); 1981 1982 if ((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) { 1983 metaslab_load_wait(msp); 1984 if (!msp->ms_loaded) { 1985 int error = metaslab_load(msp); 1986 if (error) { 1987 metaslab_group_sort(msp->ms_group, msp, 0); 1988 return (error); 1989 } 1990 } 1991 1992 msp->ms_activation_weight = msp->ms_weight; 1993 metaslab_group_sort(msp->ms_group, msp, 1994 msp->ms_weight | activation_weight); 1995 } 1996 ASSERT(msp->ms_loaded); 1997 ASSERT(msp->ms_weight & METASLAB_ACTIVE_MASK); 1998 1999 return (0); 2000} 2001 2002static void 2003metaslab_passivate(metaslab_t *msp, uint64_t weight) 2004{ 2005 uint64_t size = weight & ~METASLAB_WEIGHT_TYPE; 2006 2007 /* 2008 * If size < SPA_MINBLOCKSIZE, then we will not allocate from 2009 * this metaslab again. In that case, it had better be empty, 2010 * or we would be leaving space on the table. 2011 */ 2012 ASSERT(size >= SPA_MINBLOCKSIZE || 2013 range_tree_space(msp->ms_tree) == 0); 2014 ASSERT0(weight & METASLAB_ACTIVE_MASK); 2015 2016 msp->ms_activation_weight = 0; 2017 metaslab_group_sort(msp->ms_group, msp, weight); 2018 ASSERT((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0); 2019} 2020 2021/* 2022 * Segment-based metaslabs are activated once and remain active until 2023 * we either fail an allocation attempt (similar to space-based metaslabs) 2024 * or have exhausted the free space in zfs_metaslab_switch_threshold 2025 * buckets since the metaslab was activated. This function checks to see 2026 * if we've exhaused the zfs_metaslab_switch_threshold buckets in the 2027 * metaslab and passivates it proactively. This will allow us to select a 2028 * metaslabs with larger contiguous region if any remaining within this 2029 * metaslab group. If we're in sync pass > 1, then we continue using this 2030 * metaslab so that we don't dirty more block and cause more sync passes. 2031 */ 2032void 2033metaslab_segment_may_passivate(metaslab_t *msp) 2034{ 2035 spa_t *spa = msp->ms_group->mg_vd->vdev_spa; 2036 2037 if (WEIGHT_IS_SPACEBASED(msp->ms_weight) || spa_sync_pass(spa) > 1) 2038 return; 2039 2040 /* 2041 * Since we are in the middle of a sync pass, the most accurate 2042 * information that is accessible to us is the in-core range tree 2043 * histogram; calculate the new weight based on that information. 2044 */ 2045 uint64_t weight = metaslab_weight_from_range_tree(msp); 2046 int activation_idx = WEIGHT_GET_INDEX(msp->ms_activation_weight); 2047 int current_idx = WEIGHT_GET_INDEX(weight); 2048 2049 if (current_idx <= activation_idx - zfs_metaslab_switch_threshold) 2050 metaslab_passivate(msp, weight); 2051} 2052 2053static void 2054metaslab_preload(void *arg) 2055{ 2056 metaslab_t *msp = arg; 2057 spa_t *spa = msp->ms_group->mg_vd->vdev_spa; 2058 2059 ASSERT(!MUTEX_HELD(&msp->ms_group->mg_lock)); 2060 2061 mutex_enter(&msp->ms_lock); 2062 metaslab_load_wait(msp); 2063 if (!msp->ms_loaded) 2064 (void) metaslab_load(msp); 2065 msp->ms_selected_txg = spa_syncing_txg(spa); 2066 mutex_exit(&msp->ms_lock); 2067} 2068 2069static void 2070metaslab_group_preload(metaslab_group_t *mg) 2071{ 2072 spa_t *spa = mg->mg_vd->vdev_spa; 2073 metaslab_t *msp; 2074 avl_tree_t *t = &mg->mg_metaslab_tree; 2075 int m = 0; 2076 2077 if (spa_shutting_down(spa) || !metaslab_preload_enabled) { 2078 taskq_wait(mg->mg_taskq); 2079 return; 2080 } 2081 2082 mutex_enter(&mg->mg_lock); 2083 /* 2084 * Load the next potential metaslabs 2085 */ 2086 for (msp = avl_first(t); msp != NULL; msp = AVL_NEXT(t, msp)) { 2087 /* 2088 * We preload only the maximum number of metaslabs specified 2089 * by metaslab_preload_limit. If a metaslab is being forced 2090 * to condense then we preload it too. This will ensure 2091 * that force condensing happens in the next txg. 2092 */ 2093 if (++m > metaslab_preload_limit && !msp->ms_condense_wanted) { 2094 continue; 2095 } 2096 2097 VERIFY(taskq_dispatch(mg->mg_taskq, metaslab_preload, 2098 msp, TQ_SLEEP) != 0); 2099 } 2100 mutex_exit(&mg->mg_lock); 2101} 2102 2103/* 2104 * Determine if the space map's on-disk footprint is past our tolerance 2105 * for inefficiency. We would like to use the following criteria to make 2106 * our decision: 2107 * 2108 * 1. The size of the space map object should not dramatically increase as a 2109 * result of writing out the free space range tree. 2110 * 2111 * 2. The minimal on-disk space map representation is zfs_condense_pct/100 2112 * times the size than the free space range tree representation 2113 * (i.e. zfs_condense_pct = 110 and in-core = 1MB, minimal = 1.1.MB). 2114 * 2115 * 3. The on-disk size of the space map should actually decrease. 2116 * 2117 * Checking the first condition is tricky since we don't want to walk 2118 * the entire AVL tree calculating the estimated on-disk size. Instead we 2119 * use the size-ordered range tree in the metaslab and calculate the 2120 * size required to write out the largest segment in our free tree. If the 2121 * size required to represent that segment on disk is larger than the space 2122 * map object then we avoid condensing this map. 2123 * 2124 * To determine the second criterion we use a best-case estimate and assume 2125 * each segment can be represented on-disk as a single 64-bit entry. We refer 2126 * to this best-case estimate as the space map's minimal form. 2127 * 2128 * Unfortunately, we cannot compute the on-disk size of the space map in this 2129 * context because we cannot accurately compute the effects of compression, etc. 2130 * Instead, we apply the heuristic described in the block comment for 2131 * zfs_metaslab_condense_block_threshold - we only condense if the space used 2132 * is greater than a threshold number of blocks. 2133 */ 2134static boolean_t 2135metaslab_should_condense(metaslab_t *msp) 2136{ 2137 space_map_t *sm = msp->ms_sm; 2138 range_seg_t *rs; 2139 uint64_t size, entries, segsz, object_size, optimal_size, record_size; 2140 dmu_object_info_t doi; 2141 uint64_t vdev_blocksize = 1 << msp->ms_group->mg_vd->vdev_ashift; 2142 2143 ASSERT(MUTEX_HELD(&msp->ms_lock)); 2144 ASSERT(msp->ms_loaded); 2145 2146 /* 2147 * Use the ms_size_tree range tree, which is ordered by size, to 2148 * obtain the largest segment in the free tree. We always condense 2149 * metaslabs that are empty and metaslabs for which a condense 2150 * request has been made. 2151 */ 2152 rs = avl_last(&msp->ms_size_tree); 2153 if (rs == NULL || msp->ms_condense_wanted) 2154 return (B_TRUE); 2155 2156 /* 2157 * Calculate the number of 64-bit entries this segment would 2158 * require when written to disk. If this single segment would be 2159 * larger on-disk than the entire current on-disk structure, then 2160 * clearly condensing will increase the on-disk structure size. 2161 */ 2162 size = (rs->rs_end - rs->rs_start) >> sm->sm_shift; 2163 entries = size / (MIN(size, SM_RUN_MAX)); 2164 segsz = entries * sizeof (uint64_t); 2165 2166 optimal_size = sizeof (uint64_t) * avl_numnodes(&msp->ms_tree->rt_root); 2167 object_size = space_map_length(msp->ms_sm); 2168 2169 dmu_object_info_from_db(sm->sm_dbuf, &doi); 2170 record_size = MAX(doi.doi_data_block_size, vdev_blocksize); 2171 2172 return (segsz <= object_size && 2173 object_size >= (optimal_size * zfs_condense_pct / 100) && 2174 object_size > zfs_metaslab_condense_block_threshold * record_size); 2175} 2176 2177/* 2178 * Condense the on-disk space map representation to its minimized form. 2179 * The minimized form consists of a small number of allocations followed by 2180 * the entries of the free range tree. 2181 */ 2182static void 2183metaslab_condense(metaslab_t *msp, uint64_t txg, dmu_tx_t *tx) 2184{ 2185 spa_t *spa = msp->ms_group->mg_vd->vdev_spa; 2186 range_tree_t *condense_tree; 2187 space_map_t *sm = msp->ms_sm; 2188 2189 ASSERT(MUTEX_HELD(&msp->ms_lock)); 2190 ASSERT3U(spa_sync_pass(spa), ==, 1); 2191 ASSERT(msp->ms_loaded); 2192 2193 2194 spa_dbgmsg(spa, "condensing: txg %llu, msp[%llu] %p, vdev id %llu, " 2195 "spa %s, smp size %llu, segments %lu, forcing condense=%s", txg, 2196 msp->ms_id, msp, msp->ms_group->mg_vd->vdev_id, 2197 msp->ms_group->mg_vd->vdev_spa->spa_name, 2198 space_map_length(msp->ms_sm), avl_numnodes(&msp->ms_tree->rt_root), 2199 msp->ms_condense_wanted ? "TRUE" : "FALSE"); 2200 2201 msp->ms_condense_wanted = B_FALSE; 2202 2203 /* 2204 * Create an range tree that is 100% allocated. We remove segments 2205 * that have been freed in this txg, any deferred frees that exist, 2206 * and any allocation in the future. Removing segments should be 2207 * a relatively inexpensive operation since we expect these trees to 2208 * have a small number of nodes. 2209 */ 2210 condense_tree = range_tree_create(NULL, NULL, &msp->ms_lock); 2211 range_tree_add(condense_tree, msp->ms_start, msp->ms_size); 2212 2213 /* 2214 * Remove what's been freed in this txg from the condense_tree. 2215 * Since we're in sync_pass 1, we know that all the frees from 2216 * this txg are in the freeingtree. 2217 */ 2218 range_tree_walk(msp->ms_freeingtree, range_tree_remove, condense_tree); 2219 2220 for (int t = 0; t < TXG_DEFER_SIZE; t++) { 2221 range_tree_walk(msp->ms_defertree[t], 2222 range_tree_remove, condense_tree); 2223 } 2224 2225 for (int t = 1; t < TXG_CONCURRENT_STATES; t++) { 2226 range_tree_walk(msp->ms_alloctree[(txg + t) & TXG_MASK], 2227 range_tree_remove, condense_tree); 2228 } 2229 2230 /* 2231 * We're about to drop the metaslab's lock thus allowing 2232 * other consumers to change it's content. Set the 2233 * metaslab's ms_condensing flag to ensure that 2234 * allocations on this metaslab do not occur while we're 2235 * in the middle of committing it to disk. This is only critical 2236 * for the ms_tree as all other range trees use per txg 2237 * views of their content. 2238 */ 2239 msp->ms_condensing = B_TRUE; 2240 2241 mutex_exit(&msp->ms_lock); 2242 space_map_truncate(sm, tx); 2243 mutex_enter(&msp->ms_lock); 2244 2245 /* 2246 * While we would ideally like to create a space map representation 2247 * that consists only of allocation records, doing so can be 2248 * prohibitively expensive because the in-core free tree can be 2249 * large, and therefore computationally expensive to subtract 2250 * from the condense_tree. Instead we sync out two trees, a cheap 2251 * allocation only tree followed by the in-core free tree. While not 2252 * optimal, this is typically close to optimal, and much cheaper to 2253 * compute. 2254 */ 2255 space_map_write(sm, condense_tree, SM_ALLOC, tx); 2256 range_tree_vacate(condense_tree, NULL, NULL); 2257 range_tree_destroy(condense_tree); 2258 2259 space_map_write(sm, msp->ms_tree, SM_FREE, tx); 2260 msp->ms_condensing = B_FALSE; 2261} 2262 2263/* 2264 * Write a metaslab to disk in the context of the specified transaction group. 2265 */ 2266void 2267metaslab_sync(metaslab_t *msp, uint64_t txg) 2268{ 2269 metaslab_group_t *mg = msp->ms_group; 2270 vdev_t *vd = mg->mg_vd; 2271 spa_t *spa = vd->vdev_spa; 2272 objset_t *mos = spa_meta_objset(spa); 2273 range_tree_t *alloctree = msp->ms_alloctree[txg & TXG_MASK]; 2274 dmu_tx_t *tx; 2275 uint64_t object = space_map_object(msp->ms_sm); 2276 2277 ASSERT(!vd->vdev_ishole); 2278 2279 /* 2280 * This metaslab has just been added so there's no work to do now. 2281 */ 2282 if (msp->ms_freeingtree == NULL) { 2283 ASSERT3P(alloctree, ==, NULL); 2284 return; 2285 } 2286 2287 ASSERT3P(alloctree, !=, NULL); 2288 ASSERT3P(msp->ms_freeingtree, !=, NULL); 2289 ASSERT3P(msp->ms_freedtree, !=, NULL); 2290 2291 /* 2292 * Normally, we don't want to process a metaslab if there 2293 * are no allocations or frees to perform. However, if the metaslab 2294 * is being forced to condense and it's loaded, we need to let it 2295 * through. 2296 */ 2297 if (range_tree_space(alloctree) == 0 && 2298 range_tree_space(msp->ms_freeingtree) == 0 && 2299 !(msp->ms_loaded && msp->ms_condense_wanted)) 2300 return; 2301 2302 2303 VERIFY(txg <= spa_final_dirty_txg(spa)); 2304 2305 /* 2306 * The only state that can actually be changing concurrently with 2307 * metaslab_sync() is the metaslab's ms_tree. No other thread can 2308 * be modifying this txg's alloctree, freeingtree, freedtree, or 2309 * space_map_phys_t. Therefore, we only hold ms_lock to satify 2310 * space map ASSERTs. We drop it whenever we call into the DMU, 2311 * because the DMU can call down to us (e.g. via zio_free()) at 2312 * any time. 2313 */ 2314 2315 tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg); 2316 2317 if (msp->ms_sm == NULL) { 2318 uint64_t new_object; 2319 2320 new_object = space_map_alloc(mos, tx); 2321 VERIFY3U(new_object, !=, 0); 2322 2323 VERIFY0(space_map_open(&msp->ms_sm, mos, new_object, 2324 msp->ms_start, msp->ms_size, vd->vdev_ashift, 2325 &msp->ms_lock)); 2326 ASSERT(msp->ms_sm != NULL); 2327 } 2328 2329 mutex_enter(&msp->ms_lock); 2330 2331 /* 2332 * Note: metaslab_condense() clears the space map's histogram. 2333 * Therefore we must verify and remove this histogram before 2334 * condensing. 2335 */ 2336 metaslab_group_histogram_verify(mg); 2337 metaslab_class_histogram_verify(mg->mg_class); 2338 metaslab_group_histogram_remove(mg, msp); 2339 2340 if (msp->ms_loaded && spa_sync_pass(spa) == 1 && 2341 metaslab_should_condense(msp)) { 2342 metaslab_condense(msp, txg, tx); 2343 } else { 2344 space_map_write(msp->ms_sm, alloctree, SM_ALLOC, tx); 2345 space_map_write(msp->ms_sm, msp->ms_freeingtree, SM_FREE, tx); 2346 } 2347 2348 if (msp->ms_loaded) { 2349 /* 2350 * When the space map is loaded, we have an accruate 2351 * histogram in the range tree. This gives us an opportunity 2352 * to bring the space map's histogram up-to-date so we clear 2353 * it first before updating it. 2354 */ 2355 space_map_histogram_clear(msp->ms_sm); 2356 space_map_histogram_add(msp->ms_sm, msp->ms_tree, tx); 2357 2358 /* 2359 * Since we've cleared the histogram we need to add back 2360 * any free space that has already been processed, plus 2361 * any deferred space. This allows the on-disk histogram 2362 * to accurately reflect all free space even if some space 2363 * is not yet available for allocation (i.e. deferred). 2364 */ 2365 space_map_histogram_add(msp->ms_sm, msp->ms_freedtree, tx); 2366 2367 /* 2368 * Add back any deferred free space that has not been 2369 * added back into the in-core free tree yet. This will 2370 * ensure that we don't end up with a space map histogram 2371 * that is completely empty unless the metaslab is fully 2372 * allocated. 2373 */ 2374 for (int t = 0; t < TXG_DEFER_SIZE; t++) { 2375 space_map_histogram_add(msp->ms_sm, 2376 msp->ms_defertree[t], tx); 2377 } 2378 } 2379 2380 /* 2381 * Always add the free space from this sync pass to the space 2382 * map histogram. We want to make sure that the on-disk histogram 2383 * accounts for all free space. If the space map is not loaded, 2384 * then we will lose some accuracy but will correct it the next 2385 * time we load the space map. 2386 */ 2387 space_map_histogram_add(msp->ms_sm, msp->ms_freeingtree, tx); 2388 2389 metaslab_group_histogram_add(mg, msp); 2390 metaslab_group_histogram_verify(mg); 2391 metaslab_class_histogram_verify(mg->mg_class); 2392 2393 /* 2394 * For sync pass 1, we avoid traversing this txg's free range tree 2395 * and instead will just swap the pointers for freeingtree and 2396 * freedtree. We can safely do this since the freed_tree is 2397 * guaranteed to be empty on the initial pass. 2398 */ 2399 if (spa_sync_pass(spa) == 1) { 2400 range_tree_swap(&msp->ms_freeingtree, &msp->ms_freedtree); 2401 } else { 2402 range_tree_vacate(msp->ms_freeingtree, 2403 range_tree_add, msp->ms_freedtree); 2404 } 2405 range_tree_vacate(alloctree, NULL, NULL); 2406 2407 ASSERT0(range_tree_space(msp->ms_alloctree[txg & TXG_MASK])); 2408 ASSERT0(range_tree_space(msp->ms_alloctree[TXG_CLEAN(txg) & TXG_MASK])); 2409 ASSERT0(range_tree_space(msp->ms_freeingtree)); 2410 2411 mutex_exit(&msp->ms_lock); 2412 2413 if (object != space_map_object(msp->ms_sm)) { 2414 object = space_map_object(msp->ms_sm); 2415 dmu_write(mos, vd->vdev_ms_array, sizeof (uint64_t) * 2416 msp->ms_id, sizeof (uint64_t), &object, tx); 2417 } 2418 dmu_tx_commit(tx); 2419} 2420 2421/* 2422 * Called after a transaction group has completely synced to mark 2423 * all of the metaslab's free space as usable. 2424 */ 2425void 2426metaslab_sync_done(metaslab_t *msp, uint64_t txg) 2427{ 2428 metaslab_group_t *mg = msp->ms_group; 2429 vdev_t *vd = mg->mg_vd; 2430 spa_t *spa = vd->vdev_spa; 2431 range_tree_t **defer_tree; 2432 int64_t alloc_delta, defer_delta; 2433 boolean_t defer_allowed = B_TRUE; 2434 2435 ASSERT(!vd->vdev_ishole); 2436 2437 mutex_enter(&msp->ms_lock); 2438 2439 /* 2440 * If this metaslab is just becoming available, initialize its 2441 * range trees and add its capacity to the vdev. 2442 */ 2443 if (msp->ms_freedtree == NULL) { 2444 for (int t = 0; t < TXG_SIZE; t++) { 2445 ASSERT(msp->ms_alloctree[t] == NULL); 2446 2447 msp->ms_alloctree[t] = range_tree_create(NULL, msp, 2448 &msp->ms_lock); 2449 } 2450 2451 ASSERT3P(msp->ms_freeingtree, ==, NULL); 2452 msp->ms_freeingtree = range_tree_create(NULL, msp, 2453 &msp->ms_lock); 2454 2455 ASSERT3P(msp->ms_freedtree, ==, NULL); 2456 msp->ms_freedtree = range_tree_create(NULL, msp, 2457 &msp->ms_lock); 2458 2459 for (int t = 0; t < TXG_DEFER_SIZE; t++) { 2460 ASSERT(msp->ms_defertree[t] == NULL); 2461 2462 msp->ms_defertree[t] = range_tree_create(NULL, msp, 2463 &msp->ms_lock); 2464 } 2465 2466 vdev_space_update(vd, 0, 0, msp->ms_size); 2467 } 2468 2469 defer_tree = &msp->ms_defertree[txg % TXG_DEFER_SIZE]; 2470 2471 uint64_t free_space = metaslab_class_get_space(spa_normal_class(spa)) - 2472 metaslab_class_get_alloc(spa_normal_class(spa)); 2473 if (free_space <= spa_get_slop_space(spa)) { 2474 defer_allowed = B_FALSE; 2475 } 2476 2477 defer_delta = 0; 2478 alloc_delta = space_map_alloc_delta(msp->ms_sm); 2479 if (defer_allowed) { 2480 defer_delta = range_tree_space(msp->ms_freedtree) - 2481 range_tree_space(*defer_tree); 2482 } else { 2483 defer_delta -= range_tree_space(*defer_tree); 2484 } 2485 2486 vdev_space_update(vd, alloc_delta + defer_delta, defer_delta, 0); 2487 2488 /* 2489 * If there's a metaslab_load() in progress, wait for it to complete 2490 * so that we have a consistent view of the in-core space map. 2491 */ 2492 metaslab_load_wait(msp); 2493 2494 /* 2495 * Move the frees from the defer_tree back to the free 2496 * range tree (if it's loaded). Swap the freed_tree and the 2497 * defer_tree -- this is safe to do because we've just emptied out 2498 * the defer_tree. 2499 */ 2500 range_tree_vacate(*defer_tree, 2501 msp->ms_loaded ? range_tree_add : NULL, msp->ms_tree); 2502 if (defer_allowed) { 2503 range_tree_swap(&msp->ms_freedtree, defer_tree); 2504 } else { 2505 range_tree_vacate(msp->ms_freedtree, 2506 msp->ms_loaded ? range_tree_add : NULL, msp->ms_tree); 2507 } 2508 2509 space_map_update(msp->ms_sm); 2510 2511 msp->ms_deferspace += defer_delta; 2512 ASSERT3S(msp->ms_deferspace, >=, 0); 2513 ASSERT3S(msp->ms_deferspace, <=, msp->ms_size); 2514 if (msp->ms_deferspace != 0) { 2515 /* 2516 * Keep syncing this metaslab until all deferred frees 2517 * are back in circulation. 2518 */ 2519 vdev_dirty(vd, VDD_METASLAB, msp, txg + 1); 2520 } 2521 2522 /* 2523 * Calculate the new weights before unloading any metaslabs. 2524 * This will give us the most accurate weighting. 2525 */ 2526 metaslab_group_sort(mg, msp, metaslab_weight(msp)); 2527 2528 /* 2529 * If the metaslab is loaded and we've not tried to load or allocate 2530 * from it in 'metaslab_unload_delay' txgs, then unload it. 2531 */ 2532 if (msp->ms_loaded && 2533 msp->ms_selected_txg + metaslab_unload_delay < txg) { 2534 for (int t = 1; t < TXG_CONCURRENT_STATES; t++) { 2535 VERIFY0(range_tree_space( 2536 msp->ms_alloctree[(txg + t) & TXG_MASK])); 2537 } 2538 2539 if (!metaslab_debug_unload) 2540 metaslab_unload(msp); 2541 } 2542 2543 mutex_exit(&msp->ms_lock); 2544} 2545 2546void 2547metaslab_sync_reassess(metaslab_group_t *mg) 2548{ 2549 metaslab_group_alloc_update(mg); 2550 mg->mg_fragmentation = metaslab_group_fragmentation(mg); 2551 2552 /* 2553 * Preload the next potential metaslabs 2554 */ 2555 metaslab_group_preload(mg); 2556} 2557 2558static uint64_t 2559metaslab_distance(metaslab_t *msp, dva_t *dva) 2560{ 2561 uint64_t ms_shift = msp->ms_group->mg_vd->vdev_ms_shift; 2562 uint64_t offset = DVA_GET_OFFSET(dva) >> ms_shift; 2563 uint64_t start = msp->ms_id; 2564 2565 if (msp->ms_group->mg_vd->vdev_id != DVA_GET_VDEV(dva)) 2566 return (1ULL << 63); 2567 2568 if (offset < start) 2569 return ((start - offset) << ms_shift); 2570 if (offset > start) 2571 return ((offset - start) << ms_shift); 2572 return (0); 2573} 2574 2575/* 2576 * ========================================================================== 2577 * Metaslab allocation tracing facility 2578 * ========================================================================== 2579 */ 2580kstat_t *metaslab_trace_ksp; 2581kstat_named_t metaslab_trace_over_limit; 2582 2583void 2584metaslab_alloc_trace_init(void) 2585{ 2586 ASSERT(metaslab_alloc_trace_cache == NULL); 2587 metaslab_alloc_trace_cache = kmem_cache_create( 2588 "metaslab_alloc_trace_cache", sizeof (metaslab_alloc_trace_t), 2589 0, NULL, NULL, NULL, NULL, NULL, 0); 2590 metaslab_trace_ksp = kstat_create("zfs", 0, "metaslab_trace_stats", 2591 "misc", KSTAT_TYPE_NAMED, 1, KSTAT_FLAG_VIRTUAL); 2592 if (metaslab_trace_ksp != NULL) { 2593 metaslab_trace_ksp->ks_data = &metaslab_trace_over_limit; 2594 kstat_named_init(&metaslab_trace_over_limit, 2595 "metaslab_trace_over_limit", KSTAT_DATA_UINT64); 2596 kstat_install(metaslab_trace_ksp); 2597 } 2598} 2599 2600void 2601metaslab_alloc_trace_fini(void) 2602{ 2603 if (metaslab_trace_ksp != NULL) { 2604 kstat_delete(metaslab_trace_ksp); 2605 metaslab_trace_ksp = NULL; 2606 } 2607 kmem_cache_destroy(metaslab_alloc_trace_cache); 2608 metaslab_alloc_trace_cache = NULL; 2609} 2610 2611/* 2612 * Add an allocation trace element to the allocation tracing list. 2613 */ 2614static void 2615metaslab_trace_add(zio_alloc_list_t *zal, metaslab_group_t *mg, 2616 metaslab_t *msp, uint64_t psize, uint32_t dva_id, uint64_t offset) 2617{ 2618 if (!metaslab_trace_enabled) 2619 return; 2620 2621 /* 2622 * When the tracing list reaches its maximum we remove 2623 * the second element in the list before adding a new one. 2624 * By removing the second element we preserve the original 2625 * entry as a clue to what allocations steps have already been 2626 * performed. 2627 */ 2628 if (zal->zal_size == metaslab_trace_max_entries) { 2629 metaslab_alloc_trace_t *mat_next; 2630#ifdef DEBUG 2631 panic("too many entries in allocation list"); 2632#endif 2633 atomic_inc_64(&metaslab_trace_over_limit.value.ui64); 2634 zal->zal_size--; 2635 mat_next = list_next(&zal->zal_list, list_head(&zal->zal_list)); 2636 list_remove(&zal->zal_list, mat_next); 2637 kmem_cache_free(metaslab_alloc_trace_cache, mat_next); 2638 } 2639 2640 metaslab_alloc_trace_t *mat = 2641 kmem_cache_alloc(metaslab_alloc_trace_cache, KM_SLEEP); 2642 list_link_init(&mat->mat_list_node); 2643 mat->mat_mg = mg; 2644 mat->mat_msp = msp; 2645 mat->mat_size = psize; 2646 mat->mat_dva_id = dva_id; 2647 mat->mat_offset = offset; 2648 mat->mat_weight = 0; 2649 2650 if (msp != NULL) 2651 mat->mat_weight = msp->ms_weight; 2652 2653 /* 2654 * The list is part of the zio so locking is not required. Only 2655 * a single thread will perform allocations for a given zio. 2656 */ 2657 list_insert_tail(&zal->zal_list, mat); 2658 zal->zal_size++; 2659 2660 ASSERT3U(zal->zal_size, <=, metaslab_trace_max_entries); 2661} 2662 2663void 2664metaslab_trace_init(zio_alloc_list_t *zal) 2665{ 2666 list_create(&zal->zal_list, sizeof (metaslab_alloc_trace_t), 2667 offsetof(metaslab_alloc_trace_t, mat_list_node)); 2668 zal->zal_size = 0; 2669} 2670 2671void 2672metaslab_trace_fini(zio_alloc_list_t *zal) 2673{ 2674 metaslab_alloc_trace_t *mat; 2675 2676 while ((mat = list_remove_head(&zal->zal_list)) != NULL) 2677 kmem_cache_free(metaslab_alloc_trace_cache, mat); 2678 list_destroy(&zal->zal_list); 2679 zal->zal_size = 0; 2680} 2681 2682/* 2683 * ========================================================================== 2684 * Metaslab block operations 2685 * ========================================================================== 2686 */ 2687 2688static void 2689metaslab_group_alloc_increment(spa_t *spa, uint64_t vdev, void *tag, int flags) 2690{ 2691 if (!(flags & METASLAB_ASYNC_ALLOC) || 2692 flags & METASLAB_DONT_THROTTLE) 2693 return; 2694 2695 metaslab_group_t *mg = vdev_lookup_top(spa, vdev)->vdev_mg; 2696 if (!mg->mg_class->mc_alloc_throttle_enabled) 2697 return; 2698 2699 (void) refcount_add(&mg->mg_alloc_queue_depth, tag); 2700} 2701 2702void 2703metaslab_group_alloc_decrement(spa_t *spa, uint64_t vdev, void *tag, int flags) 2704{ 2705 if (!(flags & METASLAB_ASYNC_ALLOC) || 2706 flags & METASLAB_DONT_THROTTLE) 2707 return; 2708 2709 metaslab_group_t *mg = vdev_lookup_top(spa, vdev)->vdev_mg; 2710 if (!mg->mg_class->mc_alloc_throttle_enabled) 2711 return; 2712 2713 (void) refcount_remove(&mg->mg_alloc_queue_depth, tag); 2714} 2715 2716void 2717metaslab_group_alloc_verify(spa_t *spa, const blkptr_t *bp, void *tag) 2718{ 2719#ifdef ZFS_DEBUG 2720 const dva_t *dva = bp->blk_dva; 2721 int ndvas = BP_GET_NDVAS(bp); 2722 2723 for (int d = 0; d < ndvas; d++) { 2724 uint64_t vdev = DVA_GET_VDEV(&dva[d]); 2725 metaslab_group_t *mg = vdev_lookup_top(spa, vdev)->vdev_mg; 2726 VERIFY(refcount_not_held(&mg->mg_alloc_queue_depth, tag)); 2727 } 2728#endif 2729} 2730 2731static uint64_t 2732metaslab_block_alloc(metaslab_t *msp, uint64_t size, uint64_t txg) 2733{ 2734 uint64_t start; 2735 range_tree_t *rt = msp->ms_tree; 2736 metaslab_class_t *mc = msp->ms_group->mg_class; 2737 2738 VERIFY(!msp->ms_condensing); 2739 2740 start = mc->mc_ops->msop_alloc(msp, size); 2741 if (start != -1ULL) { 2742 metaslab_group_t *mg = msp->ms_group; 2743 vdev_t *vd = mg->mg_vd; 2744 2745 VERIFY0(P2PHASE(start, 1ULL << vd->vdev_ashift)); 2746 VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift)); 2747 VERIFY3U(range_tree_space(rt) - size, <=, msp->ms_size); 2748 range_tree_remove(rt, start, size); 2749 2750 if (range_tree_space(msp->ms_alloctree[txg & TXG_MASK]) == 0) 2751 vdev_dirty(mg->mg_vd, VDD_METASLAB, msp, txg); 2752 2753 range_tree_add(msp->ms_alloctree[txg & TXG_MASK], start, size); 2754 2755 /* Track the last successful allocation */ 2756 msp->ms_alloc_txg = txg; 2757 metaslab_verify_space(msp, txg); 2758 } 2759 2760 /* 2761 * Now that we've attempted the allocation we need to update the 2762 * metaslab's maximum block size since it may have changed. 2763 */ 2764 msp->ms_max_size = metaslab_block_maxsize(msp); 2765 return (start); 2766} 2767 2768static uint64_t 2769metaslab_group_alloc_normal(metaslab_group_t *mg, zio_alloc_list_t *zal, 2770 uint64_t asize, uint64_t txg, uint64_t min_distance, dva_t *dva, int d) 2771{ 2772 metaslab_t *msp = NULL; 2773 uint64_t offset = -1ULL; 2774 uint64_t activation_weight; 2775 uint64_t target_distance; 2776 int i; 2777 2778 activation_weight = METASLAB_WEIGHT_PRIMARY; 2779 for (i = 0; i < d; i++) { 2780 if (DVA_GET_VDEV(&dva[i]) == mg->mg_vd->vdev_id) { 2781 activation_weight = METASLAB_WEIGHT_SECONDARY; 2782 break; 2783 } 2784 } 2785 2786 metaslab_t *search = kmem_alloc(sizeof (*search), KM_SLEEP); 2787 search->ms_weight = UINT64_MAX; 2788 search->ms_start = 0; 2789 for (;;) { 2790 boolean_t was_active; 2791 avl_tree_t *t = &mg->mg_metaslab_tree; 2792 avl_index_t idx; 2793 2794 mutex_enter(&mg->mg_lock); 2795 2796 /* 2797 * Find the metaslab with the highest weight that is less 2798 * than what we've already tried. In the common case, this 2799 * means that we will examine each metaslab at most once. 2800 * Note that concurrent callers could reorder metaslabs 2801 * by activation/passivation once we have dropped the mg_lock. 2802 * If a metaslab is activated by another thread, and we fail 2803 * to allocate from the metaslab we have selected, we may 2804 * not try the newly-activated metaslab, and instead activate 2805 * another metaslab. This is not optimal, but generally 2806 * does not cause any problems (a possible exception being 2807 * if every metaslab is completely full except for the 2808 * the newly-activated metaslab which we fail to examine). 2809 */ 2810 msp = avl_find(t, search, &idx); 2811 if (msp == NULL) 2812 msp = avl_nearest(t, idx, AVL_AFTER); 2813 for (; msp != NULL; msp = AVL_NEXT(t, msp)) { 2814 2815 if (!metaslab_should_allocate(msp, asize)) { 2816 metaslab_trace_add(zal, mg, msp, asize, d, 2817 TRACE_TOO_SMALL); 2818 continue; 2819 } 2820 2821 /* 2822 * If the selected metaslab is condensing, skip it. 2823 */ 2824 if (msp->ms_condensing) 2825 continue; 2826 2827 was_active = msp->ms_weight & METASLAB_ACTIVE_MASK; 2828 if (activation_weight == METASLAB_WEIGHT_PRIMARY) 2829 break; 2830 2831 target_distance = min_distance + 2832 (space_map_allocated(msp->ms_sm) != 0 ? 0 : 2833 min_distance >> 1); 2834 2835 for (i = 0; i < d; i++) { 2836 if (metaslab_distance(msp, &dva[i]) < 2837 target_distance) 2838 break; 2839 } 2840 if (i == d) 2841 break; 2842 } 2843 mutex_exit(&mg->mg_lock); 2844 if (msp == NULL) { 2845 kmem_free(search, sizeof (*search)); 2846 return (-1ULL); 2847 } 2848 search->ms_weight = msp->ms_weight; 2849 search->ms_start = msp->ms_start + 1; 2850 2851 mutex_enter(&msp->ms_lock); 2852 2853 /* 2854 * Ensure that the metaslab we have selected is still 2855 * capable of handling our request. It's possible that 2856 * another thread may have changed the weight while we 2857 * were blocked on the metaslab lock. We check the 2858 * active status first to see if we need to reselect 2859 * a new metaslab. 2860 */ 2861 if (was_active && !(msp->ms_weight & METASLAB_ACTIVE_MASK)) { 2862 mutex_exit(&msp->ms_lock); 2863 continue; 2864 } 2865 2866 if ((msp->ms_weight & METASLAB_WEIGHT_SECONDARY) && 2867 activation_weight == METASLAB_WEIGHT_PRIMARY) { 2868 metaslab_passivate(msp, 2869 msp->ms_weight & ~METASLAB_ACTIVE_MASK); 2870 mutex_exit(&msp->ms_lock); 2871 continue; 2872 } 2873 2874 if (metaslab_activate(msp, activation_weight) != 0) { 2875 mutex_exit(&msp->ms_lock); 2876 continue; 2877 } 2878 msp->ms_selected_txg = txg; 2879 2880 /* 2881 * Now that we have the lock, recheck to see if we should 2882 * continue to use this metaslab for this allocation. The 2883 * the metaslab is now loaded so metaslab_should_allocate() can 2884 * accurately determine if the allocation attempt should 2885 * proceed. 2886 */ 2887 if (!metaslab_should_allocate(msp, asize)) { 2888 /* Passivate this metaslab and select a new one. */ 2889 metaslab_trace_add(zal, mg, msp, asize, d, 2890 TRACE_TOO_SMALL); 2891 goto next; 2892 } 2893 2894 /* 2895 * If this metaslab is currently condensing then pick again as 2896 * we can't manipulate this metaslab until it's committed 2897 * to disk. 2898 */ 2899 if (msp->ms_condensing) { 2900 metaslab_trace_add(zal, mg, msp, asize, d, 2901 TRACE_CONDENSING); 2902 mutex_exit(&msp->ms_lock); 2903 continue; 2904 } 2905 2906 offset = metaslab_block_alloc(msp, asize, txg); 2907 metaslab_trace_add(zal, mg, msp, asize, d, offset); 2908 2909 if (offset != -1ULL) { 2910 /* Proactively passivate the metaslab, if needed */ 2911 metaslab_segment_may_passivate(msp); 2912 break; 2913 } 2914next: 2915 ASSERT(msp->ms_loaded); 2916 2917 /* 2918 * We were unable to allocate from this metaslab so determine 2919 * a new weight for this metaslab. Now that we have loaded 2920 * the metaslab we can provide a better hint to the metaslab 2921 * selector. 2922 * 2923 * For space-based metaslabs, we use the maximum block size. 2924 * This information is only available when the metaslab 2925 * is loaded and is more accurate than the generic free 2926 * space weight that was calculated by metaslab_weight(). 2927 * This information allows us to quickly compare the maximum 2928 * available allocation in the metaslab to the allocation 2929 * size being requested. 2930 * 2931 * For segment-based metaslabs, determine the new weight 2932 * based on the highest bucket in the range tree. We 2933 * explicitly use the loaded segment weight (i.e. the range 2934 * tree histogram) since it contains the space that is 2935 * currently available for allocation and is accurate 2936 * even within a sync pass. 2937 */ 2938 if (WEIGHT_IS_SPACEBASED(msp->ms_weight)) { 2939 uint64_t weight = metaslab_block_maxsize(msp); 2940 WEIGHT_SET_SPACEBASED(weight); 2941 metaslab_passivate(msp, weight); 2942 } else { 2943 metaslab_passivate(msp, 2944 metaslab_weight_from_range_tree(msp)); 2945 } 2946 2947 /* 2948 * We have just failed an allocation attempt, check 2949 * that metaslab_should_allocate() agrees. Otherwise, 2950 * we may end up in an infinite loop retrying the same 2951 * metaslab. 2952 */ 2953 ASSERT(!metaslab_should_allocate(msp, asize)); 2954 mutex_exit(&msp->ms_lock); 2955 } 2956 mutex_exit(&msp->ms_lock); 2957 kmem_free(search, sizeof (*search)); 2958 return (offset); 2959} 2960 2961static uint64_t 2962metaslab_group_alloc(metaslab_group_t *mg, zio_alloc_list_t *zal, 2963 uint64_t asize, uint64_t txg, uint64_t min_distance, dva_t *dva, int d) 2964{ 2965 uint64_t offset; 2966 ASSERT(mg->mg_initialized); 2967 2968 offset = metaslab_group_alloc_normal(mg, zal, asize, txg, 2969 min_distance, dva, d); 2970 2971 mutex_enter(&mg->mg_lock); 2972 if (offset == -1ULL) { 2973 mg->mg_failed_allocations++; 2974 metaslab_trace_add(zal, mg, NULL, asize, d, 2975 TRACE_GROUP_FAILURE); 2976 if (asize == SPA_GANGBLOCKSIZE) { 2977 /* 2978 * This metaslab group was unable to allocate 2979 * the minimum gang block size so it must be out of 2980 * space. We must notify the allocation throttle 2981 * to start skipping allocation attempts to this 2982 * metaslab group until more space becomes available. 2983 * Note: this failure cannot be caused by the 2984 * allocation throttle since the allocation throttle 2985 * is only responsible for skipping devices and 2986 * not failing block allocations. 2987 */ 2988 mg->mg_no_free_space = B_TRUE; 2989 } 2990 } 2991 mg->mg_allocations++; 2992 mutex_exit(&mg->mg_lock); 2993 return (offset); 2994} 2995 2996/* 2997 * If we have to write a ditto block (i.e. more than one DVA for a given BP) 2998 * on the same vdev as an existing DVA of this BP, then try to allocate it 2999 * at least (vdev_asize / (2 ^ ditto_same_vdev_distance_shift)) away from the 3000 * existing DVAs. 3001 */ 3002int ditto_same_vdev_distance_shift = 3; 3003 3004/* 3005 * Allocate a block for the specified i/o. 3006 */ 3007static int 3008metaslab_alloc_dva(spa_t *spa, metaslab_class_t *mc, uint64_t psize, 3009 dva_t *dva, int d, dva_t *hintdva, uint64_t txg, int flags, 3010 zio_alloc_list_t *zal) 3011{ 3012 metaslab_group_t *mg, *rotor; 3013 vdev_t *vd; 3014 boolean_t try_hard = B_FALSE; 3015 3016 ASSERT(!DVA_IS_VALID(&dva[d])); 3017 3018 /* 3019 * For testing, make some blocks above a certain size be gang blocks. 3020 */ 3021 if (psize >= metaslab_gang_bang && (ddi_get_lbolt() & 3) == 0) { 3022 metaslab_trace_add(zal, NULL, NULL, psize, d, TRACE_FORCE_GANG); 3023 return (SET_ERROR(ENOSPC)); 3024 } 3025 3026 /* 3027 * Start at the rotor and loop through all mgs until we find something. 3028 * Note that there's no locking on mc_rotor or mc_aliquot because 3029 * nothing actually breaks if we miss a few updates -- we just won't 3030 * allocate quite as evenly. It all balances out over time. 3031 * 3032 * If we are doing ditto or log blocks, try to spread them across 3033 * consecutive vdevs. If we're forced to reuse a vdev before we've 3034 * allocated all of our ditto blocks, then try and spread them out on 3035 * that vdev as much as possible. If it turns out to not be possible, 3036 * gradually lower our standards until anything becomes acceptable. 3037 * Also, allocating on consecutive vdevs (as opposed to random vdevs) 3038 * gives us hope of containing our fault domains to something we're 3039 * able to reason about. Otherwise, any two top-level vdev failures 3040 * will guarantee the loss of data. With consecutive allocation, 3041 * only two adjacent top-level vdev failures will result in data loss. 3042 * 3043 * If we are doing gang blocks (hintdva is non-NULL), try to keep 3044 * ourselves on the same vdev as our gang block header. That 3045 * way, we can hope for locality in vdev_cache, plus it makes our 3046 * fault domains something tractable. 3047 */ 3048 if (hintdva) { 3049 vd = vdev_lookup_top(spa, DVA_GET_VDEV(&hintdva[d])); 3050 3051 /* 3052 * It's possible the vdev we're using as the hint no 3053 * longer exists (i.e. removed). Consult the rotor when 3054 * all else fails. 3055 */ 3056 if (vd != NULL) { 3057 mg = vd->vdev_mg; 3058 3059 if (flags & METASLAB_HINTBP_AVOID && 3060 mg->mg_next != NULL) 3061 mg = mg->mg_next; 3062 } else { 3063 mg = mc->mc_rotor; 3064 } 3065 } else if (d != 0) { 3066 vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[d - 1])); 3067 mg = vd->vdev_mg->mg_next; 3068 } else { 3069 mg = mc->mc_rotor; 3070 } 3071 3072 /* 3073 * If the hint put us into the wrong metaslab class, or into a 3074 * metaslab group that has been passivated, just follow the rotor. 3075 */ 3076 if (mg->mg_class != mc || mg->mg_activation_count <= 0) 3077 mg = mc->mc_rotor; 3078 3079 rotor = mg; 3080top: 3081 do { 3082 boolean_t allocatable; 3083 3084 ASSERT(mg->mg_activation_count == 1); 3085 vd = mg->mg_vd; 3086 3087 /* 3088 * Don't allocate from faulted devices. 3089 */ 3090 if (try_hard) { 3091 spa_config_enter(spa, SCL_ZIO, FTAG, RW_READER); 3092 allocatable = vdev_allocatable(vd); 3093 spa_config_exit(spa, SCL_ZIO, FTAG); 3094 } else { 3095 allocatable = vdev_allocatable(vd); 3096 } 3097 3098 /* 3099 * Determine if the selected metaslab group is eligible 3100 * for allocations. If we're ganging then don't allow 3101 * this metaslab group to skip allocations since that would 3102 * inadvertently return ENOSPC and suspend the pool 3103 * even though space is still available. 3104 */ 3105 if (allocatable && !GANG_ALLOCATION(flags) && !try_hard) { 3106 allocatable = metaslab_group_allocatable(mg, rotor, 3107 psize); 3108 } 3109 3110 if (!allocatable) { 3111 metaslab_trace_add(zal, mg, NULL, psize, d, 3112 TRACE_NOT_ALLOCATABLE); 3113 goto next; 3114 } 3115 3116 ASSERT(mg->mg_initialized); 3117 3118 /* 3119 * Avoid writing single-copy data to a failing, 3120 * non-redundant vdev, unless we've already tried all 3121 * other vdevs. 3122 */ 3123 if ((vd->vdev_stat.vs_write_errors > 0 || 3124 vd->vdev_state < VDEV_STATE_HEALTHY) && 3125 d == 0 && !try_hard && vd->vdev_children == 0) { 3126 metaslab_trace_add(zal, mg, NULL, psize, d, 3127 TRACE_VDEV_ERROR); 3128 goto next; 3129 } 3130 3131 ASSERT(mg->mg_class == mc); 3132 3133 /* 3134 * If we don't need to try hard, then require that the 3135 * block be 1/8th of the device away from any other DVAs 3136 * in this BP. If we are trying hard, allow any offset 3137 * to be used (distance=0). 3138 */ 3139 uint64_t distance = 0; 3140 if (!try_hard) { 3141 distance = vd->vdev_asize >> 3142 ditto_same_vdev_distance_shift; 3143 if (distance <= (1ULL << vd->vdev_ms_shift)) 3144 distance = 0; 3145 } 3146 3147 uint64_t asize = vdev_psize_to_asize(vd, psize); 3148 ASSERT(P2PHASE(asize, 1ULL << vd->vdev_ashift) == 0); 3149 3150 uint64_t offset = metaslab_group_alloc(mg, zal, asize, txg, 3151 distance, dva, d); 3152 3153 if (offset != -1ULL) { 3154 /* 3155 * If we've just selected this metaslab group, 3156 * figure out whether the corresponding vdev is 3157 * over- or under-used relative to the pool, 3158 * and set an allocation bias to even it out. 3159 */ 3160 if (mc->mc_aliquot == 0 && metaslab_bias_enabled) { 3161 vdev_stat_t *vs = &vd->vdev_stat; 3162 int64_t vu, cu; 3163 3164 vu = (vs->vs_alloc * 100) / (vs->vs_space + 1); 3165 cu = (mc->mc_alloc * 100) / (mc->mc_space + 1); 3166 3167 /* 3168 * Calculate how much more or less we should 3169 * try to allocate from this device during 3170 * this iteration around the rotor. 3171 * For example, if a device is 80% full 3172 * and the pool is 20% full then we should 3173 * reduce allocations by 60% on this device. 3174 * 3175 * mg_bias = (20 - 80) * 512K / 100 = -307K 3176 * 3177 * This reduces allocations by 307K for this 3178 * iteration. 3179 */ 3180 mg->mg_bias = ((cu - vu) * 3181 (int64_t)mg->mg_aliquot) / 100; 3182 } else if (!metaslab_bias_enabled) { 3183 mg->mg_bias = 0; 3184 } 3185 3186 if (atomic_add_64_nv(&mc->mc_aliquot, asize) >= 3187 mg->mg_aliquot + mg->mg_bias) { 3188 mc->mc_rotor = mg->mg_next; 3189 mc->mc_aliquot = 0; 3190 } 3191 3192 DVA_SET_VDEV(&dva[d], vd->vdev_id); 3193 DVA_SET_OFFSET(&dva[d], offset); 3194 DVA_SET_GANG(&dva[d], !!(flags & METASLAB_GANG_HEADER)); 3195 DVA_SET_ASIZE(&dva[d], asize); 3196 3197 return (0); 3198 } 3199next: 3200 mc->mc_rotor = mg->mg_next; 3201 mc->mc_aliquot = 0; 3202 } while ((mg = mg->mg_next) != rotor); 3203 3204 /* 3205 * If we haven't tried hard, do so now. 3206 */ 3207 if (!try_hard) { 3208 try_hard = B_TRUE; 3209 goto top; 3210 } 3211 3212 bzero(&dva[d], sizeof (dva_t)); 3213 3214 metaslab_trace_add(zal, rotor, NULL, psize, d, TRACE_ENOSPC); 3215 return (SET_ERROR(ENOSPC)); 3216} 3217 3218/* 3219 * Free the block represented by DVA in the context of the specified 3220 * transaction group. 3221 */ 3222static void 3223metaslab_free_dva(spa_t *spa, const dva_t *dva, uint64_t txg, boolean_t now) 3224{ 3225 uint64_t vdev = DVA_GET_VDEV(dva); 3226 uint64_t offset = DVA_GET_OFFSET(dva); 3227 uint64_t size = DVA_GET_ASIZE(dva); 3228 vdev_t *vd; 3229 metaslab_t *msp; 3230 3231 ASSERT(DVA_IS_VALID(dva)); 3232 3233 if (txg > spa_freeze_txg(spa)) 3234 return; 3235 3236 if ((vd = vdev_lookup_top(spa, vdev)) == NULL || 3237 (offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count) { 3238 cmn_err(CE_WARN, "metaslab_free_dva(): bad DVA %llu:%llu", 3239 (u_longlong_t)vdev, (u_longlong_t)offset); 3240 ASSERT(0); 3241 return; 3242 } 3243 3244 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift]; 3245 3246 if (DVA_GET_GANG(dva)) 3247 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE); 3248 3249 mutex_enter(&msp->ms_lock); 3250 3251 if (now) { 3252 range_tree_remove(msp->ms_alloctree[txg & TXG_MASK], 3253 offset, size); 3254 3255 VERIFY(!msp->ms_condensing); 3256 VERIFY3U(offset, >=, msp->ms_start); 3257 VERIFY3U(offset + size, <=, msp->ms_start + msp->ms_size); 3258 VERIFY3U(range_tree_space(msp->ms_tree) + size, <=, 3259 msp->ms_size); 3260 VERIFY0(P2PHASE(offset, 1ULL << vd->vdev_ashift)); 3261 VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift)); 3262 range_tree_add(msp->ms_tree, offset, size); 3263 msp->ms_max_size = metaslab_block_maxsize(msp); 3264 } else { 3265 VERIFY3U(txg, ==, spa->spa_syncing_txg); 3266 if (range_tree_space(msp->ms_freeingtree) == 0) 3267 vdev_dirty(vd, VDD_METASLAB, msp, txg); 3268 range_tree_add(msp->ms_freeingtree, offset, size); 3269 } 3270 3271 mutex_exit(&msp->ms_lock); 3272} 3273 3274/* 3275 * Intent log support: upon opening the pool after a crash, notify the SPA 3276 * of blocks that the intent log has allocated for immediate write, but 3277 * which are still considered free by the SPA because the last transaction 3278 * group didn't commit yet. 3279 */ 3280static int 3281metaslab_claim_dva(spa_t *spa, const dva_t *dva, uint64_t txg) 3282{ 3283 uint64_t vdev = DVA_GET_VDEV(dva); 3284 uint64_t offset = DVA_GET_OFFSET(dva); 3285 uint64_t size = DVA_GET_ASIZE(dva); 3286 vdev_t *vd; 3287 metaslab_t *msp; 3288 int error = 0; 3289 3290 ASSERT(DVA_IS_VALID(dva)); 3291 3292 if ((vd = vdev_lookup_top(spa, vdev)) == NULL || 3293 (offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count) 3294 return (SET_ERROR(ENXIO)); 3295 3296 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift]; 3297 3298 if (DVA_GET_GANG(dva)) 3299 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE); 3300 3301 mutex_enter(&msp->ms_lock); 3302 3303 if ((txg != 0 && spa_writeable(spa)) || !msp->ms_loaded) 3304 error = metaslab_activate(msp, METASLAB_WEIGHT_SECONDARY); 3305 3306 if (error == 0 && !range_tree_contains(msp->ms_tree, offset, size)) 3307 error = SET_ERROR(ENOENT); 3308 3309 if (error || txg == 0) { /* txg == 0 indicates dry run */ 3310 mutex_exit(&msp->ms_lock); 3311 return (error); 3312 } 3313 3314 VERIFY(!msp->ms_condensing); 3315 VERIFY0(P2PHASE(offset, 1ULL << vd->vdev_ashift)); 3316 VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift)); 3317 VERIFY3U(range_tree_space(msp->ms_tree) - size, <=, msp->ms_size); 3318 range_tree_remove(msp->ms_tree, offset, size); 3319 3320 if (spa_writeable(spa)) { /* don't dirty if we're zdb(1M) */ 3321 if (range_tree_space(msp->ms_alloctree[txg & TXG_MASK]) == 0) 3322 vdev_dirty(vd, VDD_METASLAB, msp, txg); 3323 range_tree_add(msp->ms_alloctree[txg & TXG_MASK], offset, size); 3324 } 3325 3326 mutex_exit(&msp->ms_lock); 3327 3328 return (0); 3329} 3330 3331/* 3332 * Reserve some allocation slots. The reservation system must be called 3333 * before we call into the allocator. If there aren't any available slots 3334 * then the I/O will be throttled until an I/O completes and its slots are 3335 * freed up. The function returns true if it was successful in placing 3336 * the reservation. 3337 */ 3338boolean_t 3339metaslab_class_throttle_reserve(metaslab_class_t *mc, int slots, zio_t *zio, 3340 int flags) 3341{ 3342 uint64_t available_slots = 0; 3343 boolean_t slot_reserved = B_FALSE; 3344 3345 ASSERT(mc->mc_alloc_throttle_enabled); 3346 mutex_enter(&mc->mc_lock); 3347 3348 uint64_t reserved_slots = refcount_count(&mc->mc_alloc_slots); 3349 if (reserved_slots < mc->mc_alloc_max_slots) 3350 available_slots = mc->mc_alloc_max_slots - reserved_slots; 3351 3352 if (slots <= available_slots || GANG_ALLOCATION(flags)) { 3353 /* 3354 * We reserve the slots individually so that we can unreserve 3355 * them individually when an I/O completes. 3356 */ 3357 for (int d = 0; d < slots; d++) { 3358 reserved_slots = refcount_add(&mc->mc_alloc_slots, zio); 3359 } 3360 zio->io_flags |= ZIO_FLAG_IO_ALLOCATING; 3361 slot_reserved = B_TRUE; 3362 } 3363 3364 mutex_exit(&mc->mc_lock); 3365 return (slot_reserved); 3366} 3367 3368void 3369metaslab_class_throttle_unreserve(metaslab_class_t *mc, int slots, zio_t *zio) 3370{ 3371 ASSERT(mc->mc_alloc_throttle_enabled); 3372 mutex_enter(&mc->mc_lock); 3373 for (int d = 0; d < slots; d++) { 3374 (void) refcount_remove(&mc->mc_alloc_slots, zio); 3375 } 3376 mutex_exit(&mc->mc_lock); 3377} 3378 3379int 3380metaslab_alloc(spa_t *spa, metaslab_class_t *mc, uint64_t psize, blkptr_t *bp, 3381 int ndvas, uint64_t txg, blkptr_t *hintbp, int flags, 3382 zio_alloc_list_t *zal, zio_t *zio) 3383{ 3384 dva_t *dva = bp->blk_dva; 3385 dva_t *hintdva = hintbp->blk_dva; 3386 int error = 0; 3387 3388 ASSERT(bp->blk_birth == 0); 3389 ASSERT(BP_PHYSICAL_BIRTH(bp) == 0); 3390 3391 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER); 3392 3393 if (mc->mc_rotor == NULL) { /* no vdevs in this class */ 3394 spa_config_exit(spa, SCL_ALLOC, FTAG); 3395 return (SET_ERROR(ENOSPC)); 3396 } 3397 3398 ASSERT(ndvas > 0 && ndvas <= spa_max_replication(spa)); 3399 ASSERT(BP_GET_NDVAS(bp) == 0); 3400 ASSERT(hintbp == NULL || ndvas <= BP_GET_NDVAS(hintbp)); 3401 ASSERT3P(zal, !=, NULL); 3402 3403 for (int d = 0; d < ndvas; d++) { 3404 error = metaslab_alloc_dva(spa, mc, psize, dva, d, hintdva, 3405 txg, flags, zal); 3406 if (error != 0) { 3407 for (d--; d >= 0; d--) { 3408 metaslab_free_dva(spa, &dva[d], txg, B_TRUE); 3409 metaslab_group_alloc_decrement(spa, 3410 DVA_GET_VDEV(&dva[d]), zio, flags); 3411 bzero(&dva[d], sizeof (dva_t)); 3412 } 3413 spa_config_exit(spa, SCL_ALLOC, FTAG); 3414 return (error); 3415 } else { 3416 /* 3417 * Update the metaslab group's queue depth 3418 * based on the newly allocated dva. 3419 */ 3420 metaslab_group_alloc_increment(spa, 3421 DVA_GET_VDEV(&dva[d]), zio, flags); 3422 } 3423 3424 } 3425 ASSERT(error == 0); 3426 ASSERT(BP_GET_NDVAS(bp) == ndvas); 3427 3428 spa_config_exit(spa, SCL_ALLOC, FTAG); 3429 3430 BP_SET_BIRTH(bp, txg, txg); 3431 3432 return (0); 3433} 3434 3435void 3436metaslab_free(spa_t *spa, const blkptr_t *bp, uint64_t txg, boolean_t now) 3437{ 3438 const dva_t *dva = bp->blk_dva; 3439 int ndvas = BP_GET_NDVAS(bp); 3440 3441 ASSERT(!BP_IS_HOLE(bp)); 3442 ASSERT(!now || bp->blk_birth >= spa_syncing_txg(spa)); 3443 3444 spa_config_enter(spa, SCL_FREE, FTAG, RW_READER); 3445 3446 for (int d = 0; d < ndvas; d++) 3447 metaslab_free_dva(spa, &dva[d], txg, now); 3448 3449 spa_config_exit(spa, SCL_FREE, FTAG); 3450} 3451 3452int 3453metaslab_claim(spa_t *spa, const blkptr_t *bp, uint64_t txg) 3454{ 3455 const dva_t *dva = bp->blk_dva; 3456 int ndvas = BP_GET_NDVAS(bp); 3457 int error = 0; 3458 3459 ASSERT(!BP_IS_HOLE(bp)); 3460 3461 if (txg != 0) { 3462 /* 3463 * First do a dry run to make sure all DVAs are claimable, 3464 * so we don't have to unwind from partial failures below. 3465 */ 3466 if ((error = metaslab_claim(spa, bp, 0)) != 0) 3467 return (error); 3468 } 3469 3470 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER); 3471 3472 for (int d = 0; d < ndvas; d++) 3473 if ((error = metaslab_claim_dva(spa, &dva[d], txg)) != 0) 3474 break; 3475 3476 spa_config_exit(spa, SCL_ALLOC, FTAG); 3477 3478 ASSERT(error == 0 || txg == 0); 3479 3480 return (error); 3481} 3482 3483void 3484metaslab_check_free(spa_t *spa, const blkptr_t *bp) 3485{ 3486 if ((zfs_flags & ZFS_DEBUG_ZIO_FREE) == 0) 3487 return; 3488 3489 spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER); 3490 for (int i = 0; i < BP_GET_NDVAS(bp); i++) { 3491 uint64_t vdev = DVA_GET_VDEV(&bp->blk_dva[i]); 3492 vdev_t *vd = vdev_lookup_top(spa, vdev); 3493 uint64_t offset = DVA_GET_OFFSET(&bp->blk_dva[i]); 3494 uint64_t size = DVA_GET_ASIZE(&bp->blk_dva[i]); 3495 metaslab_t *msp = vd->vdev_ms[offset >> vd->vdev_ms_shift]; 3496 3497 if (msp->ms_loaded) 3498 range_tree_verify(msp->ms_tree, offset, size); 3499 3500 range_tree_verify(msp->ms_freeingtree, offset, size); 3501 range_tree_verify(msp->ms_freedtree, offset, size); 3502 for (int j = 0; j < TXG_DEFER_SIZE; j++) 3503 range_tree_verify(msp->ms_defertree[j], offset, size); 3504 } 3505 spa_config_exit(spa, SCL_VDEV, FTAG); 3506} 3507