module/zfs/vdev_queue.c

   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 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /*
  27  * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
  28  */
  29
  30 #include <sys/zfs_context.h>
  31 #include <sys/vdev_impl.h>
  32 #include <sys/spa_impl.h>
  33 #include <sys/zio.h>
  34 #include <sys/avl.h>
  35 #include <sys/dsl_pool.h>
  36 #include <sys/metaslab_impl.h>
  37 #include <sys/spa.h>
  38 #include <sys/abd.h>
  39
  40 /*
  41  * ZFS I/O Scheduler
  42  * ---------------
  43  *
  44  * ZFS issues I/O operations to leaf vdevs to satisfy and complete zios.  The
  45  * I/O scheduler determines when and in what order those operations are
  46  * issued.  The I/O scheduler divides operations into five I/O classes
  47  * prioritized in the following order: sync read, sync write, async read,
  48  * async write, and scrub/resilver.  Each queue defines the minimum and
  49  * maximum number of concurrent operations that may be issued to the device.
  50  * In addition, the device has an aggregate maximum. Note that the sum of the
  51  * per-queue minimums must not exceed the aggregate maximum. If the
  52  * sum of the per-queue maximums exceeds the aggregate maximum, then the
  53  * number of active i/os may reach zfs_vdev_max_active, in which case no
  54  * further i/os will be issued regardless of whether all per-queue
  55  * minimums have been met.
  56  *
  57  * For many physical devices, throughput increases with the number of
  58  * concurrent operations, but latency typically suffers. Further, physical
  59  * devices typically have a limit at which more concurrent operations have no
  60  * effect on throughput or can actually cause it to decrease.
  61  *
  62  * The scheduler selects the next operation to issue by first looking for an
  63  * I/O class whose minimum has not been satisfied. Once all are satisfied and
  64  * the aggregate maximum has not been hit, the scheduler looks for classes
  65  * whose maximum has not been satisfied. Iteration through the I/O classes is
  66  * done in the order specified above. No further operations are issued if the
  67  * aggregate maximum number of concurrent operations has been hit or if there
  68  * are no operations queued for an I/O class that has not hit its maximum.
  69  * Every time an i/o is queued or an operation completes, the I/O scheduler
  70  * looks for new operations to issue.
  71  *
  72  * All I/O classes have a fixed maximum number of outstanding operations
  73  * except for the async write class. Asynchronous writes represent the data
  74  * that is committed to stable storage during the syncing stage for
  75  * transaction groups (see txg.c). Transaction groups enter the syncing state
  76  * periodically so the number of queued async writes will quickly burst up and
  77  * then bleed down to zero. Rather than servicing them as quickly as possible,
  78  * the I/O scheduler changes the maximum number of active async write i/os
  79  * according to the amount of dirty data in the pool (see dsl_pool.c). Since
  80  * both throughput and latency typically increase with the number of
  81  * concurrent operations issued to physical devices, reducing the burstiness
  82  * in the number of concurrent operations also stabilizes the response time of
  83  * operations from other -- and in particular synchronous -- queues. In broad
  84  * strokes, the I/O scheduler will issue more concurrent operations from the
  85  * async write queue as there's more dirty data in the pool.
  86  *
  87  * Async Writes
  88  *
  89  * The number of concurrent operations issued for the async write I/O class
  90  * follows a piece-wise linear function defined by a few adjustable points.
  91  *
  92  *        |                   o---------| <-- zfs_vdev_async_write_max_active
  93  *   ^    |                  /^         |
  94  *   |    |                 / |         |
  95  * active |                /  |         |
  96  *  I/O   |               /   |         |
  97  * count  |              /    |         |
  98  *        |             /     |         |
  99  *        |------------o      |         | <-- zfs_vdev_async_write_min_active
 100  *       0|____________^______|_________|
 101  *        0%           |      |       100% of zfs_dirty_data_max
 102  *                     |      |
 103  *                     |      `-- zfs_vdev_async_write_active_max_dirty_percent
 104  *                     `--------- zfs_vdev_async_write_active_min_dirty_percent
 105  *
 106  * Until the amount of dirty data exceeds a minimum percentage of the dirty
 107  * data allowed in the pool, the I/O scheduler will limit the number of
 108  * concurrent operations to the minimum. As that threshold is crossed, the
 109  * number of concurrent operations issued increases linearly to the maximum at
 110  * the specified maximum percentage of the dirty data allowed in the pool.
 111  *
 112  * Ideally, the amount of dirty data on a busy pool will stay in the sloped
 113  * part of the function between zfs_vdev_async_write_active_min_dirty_percent
 114  * and zfs_vdev_async_write_active_max_dirty_percent. If it exceeds the
 115  * maximum percentage, this indicates that the rate of incoming data is
 116  * greater than the rate that the backend storage can handle. In this case, we
 117  * must further throttle incoming writes (see dmu_tx_delay() for details).
 118  */
 119
 120 /*
 121  * The maximum number of i/os active to each device.  Ideally, this will be >=
 122  * the sum of each queue's max_active.
 123  */
 124 uint32_t zfs_vdev_max_active = 1000;
 125
 126 /*
 127  * Per-queue limits on the number of i/os active to each device.  If the
 128  * number of active i/os is < zfs_vdev_max_active, then the min_active comes
 129  * into play.  We will send min_active from each queue round-robin, and then
 130  * send from queues in the order defined by zio_priority_t up to max_active.
 131  * Some queues have additional mechanisms to limit number of active I/Os in
 132  * addition to min_active and max_active, see below.
 133  *
 134  * In general, smaller max_active's will lead to lower latency of synchronous
 135  * operations.  Larger max_active's may lead to higher overall throughput,
 136  * depending on underlying storage.
 137  *
 138  * The ratio of the queues' max_actives determines the balance of performance
 139  * between reads, writes, and scrubs.  E.g., increasing
 140  * zfs_vdev_scrub_max_active will cause the scrub or resilver to complete
 141  * more quickly, but reads and writes to have higher latency and lower
 142  * throughput.
 143  */
 144 uint32_t zfs_vdev_sync_read_min_active = 10;
 145 uint32_t zfs_vdev_sync_read_max_active = 10;
 146 uint32_t zfs_vdev_sync_write_min_active = 10;
 147 uint32_t zfs_vdev_sync_write_max_active = 10;
 148 uint32_t zfs_vdev_async_read_min_active = 1;
 149 uint32_t zfs_vdev_async_read_max_active = 3;
 150 uint32_t zfs_vdev_async_write_min_active = 2;
 151 uint32_t zfs_vdev_async_write_max_active = 10;
 152 uint32_t zfs_vdev_scrub_min_active = 1;
 153 uint32_t zfs_vdev_scrub_max_active = 3;
 154 uint32_t zfs_vdev_removal_min_active = 1;
 155 uint32_t zfs_vdev_removal_max_active = 2;
 156 uint32_t zfs_vdev_initializing_min_active = 1;
 157 uint32_t zfs_vdev_initializing_max_active = 1;
 158 uint32_t zfs_vdev_trim_min_active = 1;
 159 uint32_t zfs_vdev_trim_max_active = 2;
 160 uint32_t zfs_vdev_rebuild_min_active = 1;
 161 uint32_t zfs_vdev_rebuild_max_active = 3;
 162
 163 /*
 164  * When the pool has less than zfs_vdev_async_write_active_min_dirty_percent
 165  * dirty data, use zfs_vdev_async_write_min_active.  When it has more than
 166  * zfs_vdev_async_write_active_max_dirty_percent, use
 167  * zfs_vdev_async_write_max_active. The value is linearly interpolated
 168  * between min and max.
 169  */
 170 int zfs_vdev_async_write_active_min_dirty_percent = 30;
 171 int zfs_vdev_async_write_active_max_dirty_percent = 60;
 172
 173 /*
 174  * For non-interactive I/O (scrub, resilver, removal, initialize and rebuild),
 175  * the number of concurrently-active I/O's is limited to *_min_active, unless
 176  * the vdev is "idle".  When there are no interactive I/Os active (sync or
 177  * async), and zfs_vdev_nia_delay I/Os have completed since the last
 178  * interactive I/O, then the vdev is considered to be "idle", and the number
 179  * of concurrently-active non-interactive I/O's is increased to *_max_active.
 180  */
 181 uint_t zfs_vdev_nia_delay = 5;
 182
 183 /*
 184  * Some HDDs tend to prioritize sequential I/O so high that concurrent
 185  * random I/O latency reaches several seconds.  On some HDDs it happens
 186  * even if sequential I/Os are submitted one at a time, and so setting
 187  * *_max_active to 1 does not help.  To prevent non-interactive I/Os, like
 188  * scrub, from monopolizing the device no more than zfs_vdev_nia_credit
 189  * I/Os can be sent while there are outstanding incomplete interactive
 190  * I/Os.  This enforced wait ensures the HDD services the interactive I/O
 191  * within a reasonable amount of time.
 192  */
 193 uint_t zfs_vdev_nia_credit = 5;
 194
 195 /*
 196  * To reduce IOPs, we aggregate small adjacent I/Os into one large I/O.
 197  * For read I/Os, we also aggregate across small adjacency gaps; for writes
 198  * we include spans of optional I/Os to aid aggregation at the disk even when
 199  * they aren't able to help us aggregate at this level.
 200  */
 201 int zfs_vdev_aggregation_limit = 1 << 20;
 202 int zfs_vdev_aggregation_limit_non_rotating = SPA_OLD_MAXBLOCKSIZE;
 203 int zfs_vdev_read_gap_limit = 32 << 10;
 204 int zfs_vdev_write_gap_limit = 4 << 10;
 205
 206 /*
 207  * Define the queue depth percentage for each top-level. This percentage is
 208  * used in conjunction with zfs_vdev_async_max_active to determine how many
 209  * allocations a specific top-level vdev should handle. Once the queue depth
 210  * reaches zfs_vdev_queue_depth_pct * zfs_vdev_async_write_max_active / 100
 211  * then allocator will stop allocating blocks on that top-level device.
 212  * The default kernel setting is 1000% which will yield 100 allocations per
 213  * device. For userland testing, the default setting is 300% which equates
 214  * to 30 allocations per device.
 215  */
 216 #ifdef _KERNEL
 217 int zfs_vdev_queue_depth_pct = 1000;
 218 #else
 219 int zfs_vdev_queue_depth_pct = 300;
 220 #endif
 221
 222 /*
 223  * When performing allocations for a given metaslab, we want to make sure that
 224  * there are enough IOs to aggregate together to improve throughput. We want to
 225  * ensure that there are at least 128k worth of IOs that can be aggregated, and
 226  * we assume that the average allocation size is 4k, so we need the queue depth
 227  * to be 32 per allocator to get good aggregation of sequential writes.
 228  */
 229 int zfs_vdev_def_queue_depth = 32;
 230
 231 /*
 232  * Allow TRIM I/Os to be aggregated.  This should normally not be needed since
 233  * TRIM I/O for extents up to zfs_trim_extent_bytes_max (128M) can be submitted
 234  * by the TRIM code in zfs_trim.c.
 235  */
 236 int zfs_vdev_aggregate_trim = 0;
 237
 238 static int
 239 vdev_queue_offset_compare(const void *x1, const void *x2)
 240 {
 241         const zio_t *z1 = (const zio_t *)x1;
 242         const zio_t *z2 = (const zio_t *)x2;
 243
 244         int cmp = TREE_CMP(z1->io_offset, z2->io_offset);
 245
 246         if (likely(cmp))
 247                 return (cmp);
 248
 249         return (TREE_PCMP(z1, z2));
 250 }
 251
 252 static inline avl_tree_t *
 253 vdev_queue_class_tree(vdev_queue_t *vq, zio_priority_t p)
 254 {
 255         return (&vq->vq_class[p].vqc_queued_tree);
 256 }
 257
 258 static inline avl_tree_t *
 259 vdev_queue_type_tree(vdev_queue_t *vq, zio_type_t t)
 260 {
 261         ASSERT(t == ZIO_TYPE_READ || t == ZIO_TYPE_WRITE || t == ZIO_TYPE_TRIM);
 262         if (t == ZIO_TYPE_READ)
 263                 return (&vq->vq_read_offset_tree);
 264         else if (t == ZIO_TYPE_WRITE)
 265                 return (&vq->vq_write_offset_tree);
 266         else
 267                 return (&vq->vq_trim_offset_tree);
 268 }
 269
 270 static int
 271 vdev_queue_timestamp_compare(const void *x1, const void *x2)
 272 {
 273         const zio_t *z1 = (const zio_t *)x1;
 274         const zio_t *z2 = (const zio_t *)x2;
 275
 276         int cmp = TREE_CMP(z1->io_timestamp, z2->io_timestamp);
 277
 278         if (likely(cmp))
 279                 return (cmp);
 280
 281         return (TREE_PCMP(z1, z2));
 282 }
 283
 284 static int
 285 vdev_queue_class_min_active(vdev_queue_t *vq, zio_priority_t p)
 286 {
 287         switch (p) {
 288         case ZIO_PRIORITY_SYNC_READ:
 289                 return (zfs_vdev_sync_read_min_active);
 290         case ZIO_PRIORITY_SYNC_WRITE:
 291                 return (zfs_vdev_sync_write_min_active);
 292         case ZIO_PRIORITY_ASYNC_READ:
 293                 return (zfs_vdev_async_read_min_active);
 294         case ZIO_PRIORITY_ASYNC_WRITE:
 295                 return (zfs_vdev_async_write_min_active);
 296         case ZIO_PRIORITY_SCRUB:
 297                 return (vq->vq_ia_active == 0 ? zfs_vdev_scrub_min_active :
 298                     MIN(vq->vq_nia_credit, zfs_vdev_scrub_min_active));
 299         case ZIO_PRIORITY_REMOVAL:
 300                 return (vq->vq_ia_active == 0 ? zfs_vdev_removal_min_active :
 301                     MIN(vq->vq_nia_credit, zfs_vdev_removal_min_active));
 302         case ZIO_PRIORITY_INITIALIZING:
 303                 return (vq->vq_ia_active == 0 ?zfs_vdev_initializing_min_active:
 304                     MIN(vq->vq_nia_credit, zfs_vdev_initializing_min_active));
 305         case ZIO_PRIORITY_TRIM:
 306                 return (zfs_vdev_trim_min_active);
 307         case ZIO_PRIORITY_REBUILD:
 308                 return (vq->vq_ia_active == 0 ? zfs_vdev_rebuild_min_active :
 309                     MIN(vq->vq_nia_credit, zfs_vdev_rebuild_min_active));
 310         default:
 311                 panic("invalid priority %u", p);
 312                 return (0);
 313         }
 314 }
 315
 316 static int
 317 vdev_queue_max_async_writes(spa_t *spa)
 318 {
 319         int writes;
 320         uint64_t dirty = 0;
 321         dsl_pool_t *dp = spa_get_dsl(spa);
 322         uint64_t min_bytes = zfs_dirty_data_max *
 323             zfs_vdev_async_write_active_min_dirty_percent / 100;
 324         uint64_t max_bytes = zfs_dirty_data_max *
 325             zfs_vdev_async_write_active_max_dirty_percent / 100;
 326
 327         /*
 328          * Async writes may occur before the assignment of the spa's
 329          * dsl_pool_t if a self-healing zio is issued prior to the
 330          * completion of dmu_objset_open_impl().
 331          */
 332         if (dp == NULL)
 333                 return (zfs_vdev_async_write_max_active);
 334
 335         /*
 336          * Sync tasks correspond to interactive user actions. To reduce the
 337          * execution time of those actions we push data out as fast as possible.
 338          */
 339         dirty = dp->dp_dirty_total;
 340         if (dirty > max_bytes || spa_has_pending_synctask(spa))
 341                 return (zfs_vdev_async_write_max_active);
 342
 343         if (dirty < min_bytes)
 344                 return (zfs_vdev_async_write_min_active);
 345
 346         /*
 347          * linear interpolation:
 348          * slope = (max_writes - min_writes) / (max_bytes - min_bytes)
 349          * move right by min_bytes
 350          * move up by min_writes
 351          */
 352         writes = (dirty - min_bytes) *
 353             (zfs_vdev_async_write_max_active -
 354             zfs_vdev_async_write_min_active) /
 355             (max_bytes - min_bytes) +
 356             zfs_vdev_async_write_min_active;
 357         ASSERT3U(writes, >=, zfs_vdev_async_write_min_active);
 358         ASSERT3U(writes, <=, zfs_vdev_async_write_max_active);
 359         return (writes);
 360 }
 361
 362 static int
 363 vdev_queue_class_max_active(spa_t *spa, vdev_queue_t *vq, zio_priority_t p)
 364 {
 365         switch (p) {
 366         case ZIO_PRIORITY_SYNC_READ:
 367                 return (zfs_vdev_sync_read_max_active);
 368         case ZIO_PRIORITY_SYNC_WRITE:
 369                 return (zfs_vdev_sync_write_max_active);
 370         case ZIO_PRIORITY_ASYNC_READ:
 371                 return (zfs_vdev_async_read_max_active);
 372         case ZIO_PRIORITY_ASYNC_WRITE:
 373                 return (vdev_queue_max_async_writes(spa));
 374         case ZIO_PRIORITY_SCRUB:
 375                 if (vq->vq_ia_active > 0) {
 376                         return (MIN(vq->vq_nia_credit,
 377                             zfs_vdev_scrub_min_active));
 378                 } else if (vq->vq_nia_credit < zfs_vdev_nia_delay)
 379                         return (MAX(1, zfs_vdev_scrub_min_active));
 380                 return (zfs_vdev_scrub_max_active);
 381         case ZIO_PRIORITY_REMOVAL:
 382                 if (vq->vq_ia_active > 0) {
 383                         return (MIN(vq->vq_nia_credit,
 384                             zfs_vdev_removal_min_active));
 385                 } else if (vq->vq_nia_credit < zfs_vdev_nia_delay)
 386                         return (MAX(1, zfs_vdev_removal_min_active));
 387                 return (zfs_vdev_removal_max_active);
 388         case ZIO_PRIORITY_INITIALIZING:
 389                 if (vq->vq_ia_active > 0) {
 390                         return (MIN(vq->vq_nia_credit,
 391                             zfs_vdev_initializing_min_active));
 392                 } else if (vq->vq_nia_credit < zfs_vdev_nia_delay)
 393                         return (MAX(1, zfs_vdev_initializing_min_active));
 394                 return (zfs_vdev_initializing_max_active);
 395         case ZIO_PRIORITY_TRIM:
 396                 return (zfs_vdev_trim_max_active);
 397         case ZIO_PRIORITY_REBUILD:
 398                 if (vq->vq_ia_active > 0) {
 399                         return (MIN(vq->vq_nia_credit,
 400                             zfs_vdev_rebuild_min_active));
 401                 } else if (vq->vq_nia_credit < zfs_vdev_nia_delay)
 402                         return (MAX(1, zfs_vdev_rebuild_min_active));
 403                 return (zfs_vdev_rebuild_max_active);
 404         default:
 405                 panic("invalid priority %u", p);
 406                 return (0);
 407         }
 408 }
 409
 410 /*
 411  * Return the i/o class to issue from, or ZIO_PRIORITY_MAX_QUEUEABLE if
 412  * there is no eligible class.
 413  */
 414 static zio_priority_t
 415 vdev_queue_class_to_issue(vdev_queue_t *vq)
 416 {
 417         spa_t *spa = vq->vq_vdev->vdev_spa;
 418         zio_priority_t p, n;
 419
 420         if (avl_numnodes(&vq->vq_active_tree) >= zfs_vdev_max_active)
 421                 return (ZIO_PRIORITY_NUM_QUEUEABLE);
 422
 423         /*
 424          * Find a queue that has not reached its minimum # outstanding i/os.
 425          * Do round-robin to reduce starvation due to zfs_vdev_max_active
 426          * and vq_nia_credit limits.
 427          */
 428         for (n = 0; n < ZIO_PRIORITY_NUM_QUEUEABLE; n++) {
 429                 p = (vq->vq_last_prio + n + 1) % ZIO_PRIORITY_NUM_QUEUEABLE;
 430                 if (avl_numnodes(vdev_queue_class_tree(vq, p)) > 0 &&
 431                     vq->vq_class[p].vqc_active <
 432                     vdev_queue_class_min_active(vq, p)) {
 433                         vq->vq_last_prio = p;
 434                         return (p);
 435                 }
 436         }
 437
 438         /*
 439          * If we haven't found a queue, look for one that hasn't reached its
 440          * maximum # outstanding i/os.
 441          */
 442         for (p = 0; p < ZIO_PRIORITY_NUM_QUEUEABLE; p++) {
 443                 if (avl_numnodes(vdev_queue_class_tree(vq, p)) > 0 &&
 444                     vq->vq_class[p].vqc_active <
 445                     vdev_queue_class_max_active(spa, vq, p)) {
 446                         vq->vq_last_prio = p;
 447                         return (p);
 448                 }
 449         }
 450
 451         /* No eligible queued i/os */
 452         return (ZIO_PRIORITY_NUM_QUEUEABLE);
 453 }
 454
 455 void
 456 vdev_queue_init(vdev_t *vd)
 457 {
 458         vdev_queue_t *vq = &vd->vdev_queue;
 459         zio_priority_t p;
 460
 461         mutex_init(&vq->vq_lock, NULL, MUTEX_DEFAULT, NULL);
 462         vq->vq_vdev = vd;
 463         taskq_init_ent(&vd->vdev_queue.vq_io_search.io_tqent);
 464
 465         avl_create(&vq->vq_active_tree, vdev_queue_offset_compare,
 466             sizeof (zio_t), offsetof(struct zio, io_queue_node));
 467         avl_create(vdev_queue_type_tree(vq, ZIO_TYPE_READ),
 468             vdev_queue_offset_compare, sizeof (zio_t),
 469             offsetof(struct zio, io_offset_node));
 470         avl_create(vdev_queue_type_tree(vq, ZIO_TYPE_WRITE),
 471             vdev_queue_offset_compare, sizeof (zio_t),
 472             offsetof(struct zio, io_offset_node));
 473         avl_create(vdev_queue_type_tree(vq, ZIO_TYPE_TRIM),
 474             vdev_queue_offset_compare, sizeof (zio_t),
 475             offsetof(struct zio, io_offset_node));
 476
 477         for (p = 0; p < ZIO_PRIORITY_NUM_QUEUEABLE; p++) {
 478                 int (*compfn) (const void *, const void *);
 479
 480                 /*
 481                  * The synchronous/trim i/o queues are dispatched in FIFO rather
 482                  * than LBA order. This provides more consistent latency for
 483                  * these i/os.
 484                  */
 485                 if (p == ZIO_PRIORITY_SYNC_READ ||
 486                     p == ZIO_PRIORITY_SYNC_WRITE ||
 487                     p == ZIO_PRIORITY_TRIM) {
 488                         compfn = vdev_queue_timestamp_compare;
 489                 } else {
 490                         compfn = vdev_queue_offset_compare;
 491                 }
 492                 avl_create(vdev_queue_class_tree(vq, p), compfn,
 493                     sizeof (zio_t), offsetof(struct zio, io_queue_node));
 494         }
 495
 496         vq->vq_last_offset = 0;
 497 }
 498
 499 void
 500 vdev_queue_fini(vdev_t *vd)
 501 {
 502         vdev_queue_t *vq = &vd->vdev_queue;
 503
 504         for (zio_priority_t p = 0; p < ZIO_PRIORITY_NUM_QUEUEABLE; p++)
 505                 avl_destroy(vdev_queue_class_tree(vq, p));
 506         avl_destroy(&vq->vq_active_tree);
 507         avl_destroy(vdev_queue_type_tree(vq, ZIO_TYPE_READ));
 508         avl_destroy(vdev_queue_type_tree(vq, ZIO_TYPE_WRITE));
 509         avl_destroy(vdev_queue_type_tree(vq, ZIO_TYPE_TRIM));
 510
 511         mutex_destroy(&vq->vq_lock);
 512 }
 513
 514 static void
 515 vdev_queue_io_add(vdev_queue_t *vq, zio_t *zio)
 516 {
 517         ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE);
 518         avl_add(vdev_queue_class_tree(vq, zio->io_priority), zio);
 519         avl_add(vdev_queue_type_tree(vq, zio->io_type), zio);
 520 }
 521
 522 static void
 523 vdev_queue_io_remove(vdev_queue_t *vq, zio_t *zio)
 524 {
 525         ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE);
 526         avl_remove(vdev_queue_class_tree(vq, zio->io_priority), zio);
 527         avl_remove(vdev_queue_type_tree(vq, zio->io_type), zio);
 528 }
 529
 530 static boolean_t
 531 vdev_queue_is_interactive(zio_priority_t p)
 532 {
 533         switch (p) {
 534         case ZIO_PRIORITY_SCRUB:
 535         case ZIO_PRIORITY_REMOVAL:
 536         case ZIO_PRIORITY_INITIALIZING:
 537         case ZIO_PRIORITY_REBUILD:
 538                 return (B_FALSE);
 539         default:
 540                 return (B_TRUE);
 541         }
 542 }
 543
 544 static void
 545 vdev_queue_pending_add(vdev_queue_t *vq, zio_t *zio)
 546 {
 547         ASSERT(MUTEX_HELD(&vq->vq_lock));
 548         ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE);
 549         vq->vq_class[zio->io_priority].vqc_active++;
 550         if (vdev_queue_is_interactive(zio->io_priority)) {
 551                 if (++vq->vq_ia_active == 1)
 552                         vq->vq_nia_credit = 1;
 553         } else if (vq->vq_ia_active > 0) {
 554                 vq->vq_nia_credit--;
 555         }
 556         avl_add(&vq->vq_active_tree, zio);
 557 }
 558
 559 static void
 560 vdev_queue_pending_remove(vdev_queue_t *vq, zio_t *zio)
 561 {
 562         ASSERT(MUTEX_HELD(&vq->vq_lock));
 563         ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE);
 564         vq->vq_class[zio->io_priority].vqc_active--;
 565         if (vdev_queue_is_interactive(zio->io_priority)) {
 566                 if (--vq->vq_ia_active == 0)
 567                         vq->vq_nia_credit = 0;
 568                 else
 569                         vq->vq_nia_credit = zfs_vdev_nia_credit;
 570         } else if (vq->vq_ia_active == 0)
 571                 vq->vq_nia_credit++;
 572         avl_remove(&vq->vq_active_tree, zio);
 573 }
 574
 575 static void
 576 vdev_queue_agg_io_done(zio_t *aio)
 577 {
 578         abd_free(aio->io_abd);
 579 }
 580
 581 /*
 582  * Compute the range spanned by two i/os, which is the endpoint of the last
 583  * (lio->io_offset + lio->io_size) minus start of the first (fio->io_offset).
 584  * Conveniently, the gap between fio and lio is given by -IO_SPAN(lio, fio);
 585  * thus fio and lio are adjacent if and only if IO_SPAN(lio, fio) == 0.
 586  */
 587 #define IO_SPAN(fio, lio) ((lio)->io_offset + (lio)->io_size - (fio)->io_offset)
 588 #define IO_GAP(fio, lio) (-IO_SPAN(lio, fio))
 589
 590 /*
 591  * Sufficiently adjacent io_offset's in ZIOs will be aggregated. We do this
 592  * by creating a gang ABD from the adjacent ZIOs io_abd's. By using
 593  * a gang ABD we avoid doing memory copies to and from the parent,
 594  * child ZIOs. The gang ABD also accounts for gaps between adjacent
 595  * io_offsets by simply getting the zero ABD for writes or allocating
 596  * a new ABD for reads and placing them in the gang ABD as well.
 597  */
 598 static zio_t *
 599 vdev_queue_aggregate(vdev_queue_t *vq, zio_t *zio)
 600 {
 601         zio_t *first, *last, *aio, *dio, *mandatory, *nio;
 602         zio_link_t *zl = NULL;
 603         uint64_t maxgap = 0;
 604         uint64_t size;
 605         uint64_t limit;
 606         int maxblocksize;
 607         boolean_t stretch = B_FALSE;
 608         avl_tree_t *t = vdev_queue_type_tree(vq, zio->io_type);
 609         enum zio_flag flags = zio->io_flags & ZIO_FLAG_AGG_INHERIT;
 610         uint64_t next_offset;
 611         abd_t *abd;
 612
 613         maxblocksize = spa_maxblocksize(vq->vq_vdev->vdev_spa);
 614         if (vq->vq_vdev->vdev_nonrot)
 615                 limit = zfs_vdev_aggregation_limit_non_rotating;
 616         else
 617                 limit = zfs_vdev_aggregation_limit;
 618         limit = MAX(MIN(limit, maxblocksize), 0);
 619
 620         if (zio->io_flags & ZIO_FLAG_DONT_AGGREGATE || limit == 0)
 621                 return (NULL);
 622
 623         /*
 624          * While TRIM commands could be aggregated based on offset this
 625          * behavior is disabled until it's determined to be beneficial.
 626          */
 627         if (zio->io_type == ZIO_TYPE_TRIM && !zfs_vdev_aggregate_trim)
 628                 return (NULL);
 629
 630         /*
 631          * I/Os to distributed spares are directly dispatched to the dRAID
 632          * leaf vdevs for aggregation.  See the comment at the end of the
 633          * zio_vdev_io_start() function.
 634          */
 635         ASSERT(vq->vq_vdev->vdev_ops != &vdev_draid_spare_ops);
 636
 637         first = last = zio;
 638
 639         if (zio->io_type == ZIO_TYPE_READ)
 640                 maxgap = zfs_vdev_read_gap_limit;
 641
 642         /*
 643          * We can aggregate I/Os that are sufficiently adjacent and of
 644          * the same flavor, as expressed by the AGG_INHERIT flags.
 645          * The latter requirement is necessary so that certain
 646          * attributes of the I/O, such as whether it's a normal I/O
 647          * or a scrub/resilver, can be preserved in the aggregate.
 648          * We can include optional I/Os, but don't allow them
 649          * to begin a range as they add no benefit in that situation.
 650          */
 651
 652         /*
 653          * We keep track of the last non-optional I/O.
 654          */
 655         mandatory = (first->io_flags & ZIO_FLAG_OPTIONAL) ? NULL : first;
 656
 657         /*
 658          * Walk backwards through sufficiently contiguous I/Os
 659          * recording the last non-optional I/O.
 660          */
 661         while ((dio = AVL_PREV(t, first)) != NULL &&
 662             (dio->io_flags & ZIO_FLAG_AGG_INHERIT) == flags &&
 663             IO_SPAN(dio, last) <= limit &&
 664             IO_GAP(dio, first) <= maxgap &&
 665             dio->io_type == zio->io_type) {
 666                 first = dio;
 667                 if (mandatory == NULL && !(first->io_flags & ZIO_FLAG_OPTIONAL))
 668                         mandatory = first;
 669         }
 670
 671         /*
 672          * Skip any initial optional I/Os.
 673          */
 674         while ((first->io_flags & ZIO_FLAG_OPTIONAL) && first != last) {
 675                 first = AVL_NEXT(t, first);
 676                 ASSERT(first != NULL);
 677         }
 678
 679
 680         /*
 681          * Walk forward through sufficiently contiguous I/Os.
 682          * The aggregation limit does not apply to optional i/os, so that
 683          * we can issue contiguous writes even if they are larger than the
 684          * aggregation limit.
 685          */
 686         while ((dio = AVL_NEXT(t, last)) != NULL &&
 687             (dio->io_flags & ZIO_FLAG_AGG_INHERIT) == flags &&
 688             (IO_SPAN(first, dio) <= limit ||
 689             (dio->io_flags & ZIO_FLAG_OPTIONAL)) &&
 690             IO_SPAN(first, dio) <= maxblocksize &&
 691             IO_GAP(last, dio) <= maxgap &&
 692             dio->io_type == zio->io_type) {
 693                 last = dio;
 694                 if (!(last->io_flags & ZIO_FLAG_OPTIONAL))
 695                         mandatory = last;
 696         }
 697
 698         /*
 699          * Now that we've established the range of the I/O aggregation
 700          * we must decide what to do with trailing optional I/Os.
 701          * For reads, there's nothing to do. While we are unable to
 702          * aggregate further, it's possible that a trailing optional
 703          * I/O would allow the underlying device to aggregate with
 704          * subsequent I/Os. We must therefore determine if the next
 705          * non-optional I/O is close enough to make aggregation
 706          * worthwhile.
 707          */
 708         if (zio->io_type == ZIO_TYPE_WRITE && mandatory != NULL) {
 709                 zio_t *nio = last;
 710                 while ((dio = AVL_NEXT(t, nio)) != NULL &&
 711                     IO_GAP(nio, dio) == 0 &&
 712                     IO_GAP(mandatory, dio) <= zfs_vdev_write_gap_limit) {
 713                         nio = dio;
 714                         if (!(nio->io_flags & ZIO_FLAG_OPTIONAL)) {
 715                                 stretch = B_TRUE;
 716                                 break;
 717                         }
 718                 }
 719         }
 720
 721         if (stretch) {
 722                 /*
 723                  * We are going to include an optional io in our aggregated
 724                  * span, thus closing the write gap.  Only mandatory i/os can
 725                  * start aggregated spans, so make sure that the next i/o
 726                  * after our span is mandatory.
 727                  */
 728                 dio = AVL_NEXT(t, last);
 729                 dio->io_flags &= ~ZIO_FLAG_OPTIONAL;
 730         } else {
 731                 /* do not include the optional i/o */
 732                 while (last != mandatory && last != first) {
 733                         ASSERT(last->io_flags & ZIO_FLAG_OPTIONAL);
 734                         last = AVL_PREV(t, last);
 735                         ASSERT(last != NULL);
 736                 }
 737         }
 738
 739         if (first == last)
 740                 return (NULL);
 741
 742         size = IO_SPAN(first, last);
 743         ASSERT3U(size, <=, maxblocksize);
 744
 745         abd = abd_alloc_gang();
 746         if (abd == NULL)
 747                 return (NULL);
 748
 749         aio = zio_vdev_delegated_io(first->io_vd, first->io_offset,
 750             abd, size, first->io_type, zio->io_priority,
 751             flags | ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_QUEUE,
 752             vdev_queue_agg_io_done, NULL);
 753         aio->io_timestamp = first->io_timestamp;
 754
 755         nio = first;
 756         next_offset = first->io_offset;
 757         do {
 758                 dio = nio;
 759                 nio = AVL_NEXT(t, dio);
 760                 zio_add_child(dio, aio);
 761                 vdev_queue_io_remove(vq, dio);
 762
 763                 if (dio->io_offset != next_offset) {
 764                         /* allocate a buffer for a read gap */
 765                         ASSERT3U(dio->io_type, ==, ZIO_TYPE_READ);
 766                         ASSERT3U(dio->io_offset, >, next_offset);
 767                         abd = abd_alloc_for_io(
 768                             dio->io_offset - next_offset, B_TRUE);
 769                         abd_gang_add(aio->io_abd, abd, B_TRUE);
 770                 }
 771                 if (dio->io_abd &&
 772                     (dio->io_size != abd_get_size(dio->io_abd))) {
 773                         /* abd size not the same as IO size */
 774                         ASSERT3U(abd_get_size(dio->io_abd), >, dio->io_size);
 775                         abd = abd_get_offset_size(dio->io_abd, 0, dio->io_size);
 776                         abd_gang_add(aio->io_abd, abd, B_TRUE);
 777                 } else {
 778                         if (dio->io_flags & ZIO_FLAG_NODATA) {
 779                                 /* allocate a buffer for a write gap */
 780                                 ASSERT3U(dio->io_type, ==, ZIO_TYPE_WRITE);
 781                                 ASSERT3P(dio->io_abd, ==, NULL);
 782                                 abd_gang_add(aio->io_abd,
 783                                     abd_get_zeros(dio->io_size), B_TRUE);
 784                         } else {
 785                                 /*
 786                                  * We pass B_FALSE to abd_gang_add()
 787                                  * because we did not allocate a new
 788                                  * ABD, so it is assumed the caller
 789                                  * will free this ABD.
 790                                  */
 791                                 abd_gang_add(aio->io_abd, dio->io_abd,
 792                                     B_FALSE);
 793                         }
 794                 }
 795                 next_offset = dio->io_offset + dio->io_size;
 796         } while (dio != last);
 797         ASSERT3U(abd_get_size(aio->io_abd), ==, aio->io_size);
 798
 799         /*
 800          * We need to drop the vdev queue's lock during zio_execute() to
 801          * avoid a deadlock that we could encounter due to lock order
 802          * reversal between vq_lock and io_lock in zio_change_priority().
 803          */
 804         mutex_exit(&vq->vq_lock);
 805         while ((dio = zio_walk_parents(aio, &zl)) != NULL) {
 806                 ASSERT3U(dio->io_type, ==, aio->io_type);
 807
 808                 zio_vdev_io_bypass(dio);
 809                 zio_execute(dio);
 810         }
 811         mutex_enter(&vq->vq_lock);
 812
 813         return (aio);
 814 }
 815
 816 static zio_t *
 817 vdev_queue_io_to_issue(vdev_queue_t *vq)
 818 {
 819         zio_t *zio, *aio;
 820         zio_priority_t p;
 821         avl_index_t idx;
 822         avl_tree_t *tree;
 823
 824 again:
 825         ASSERT(MUTEX_HELD(&vq->vq_lock));
 826
 827         p = vdev_queue_class_to_issue(vq);
 828
 829         if (p == ZIO_PRIORITY_NUM_QUEUEABLE) {
 830                 /* No eligible queued i/os */
 831                 return (NULL);
 832         }
 833
 834         /*
 835          * For LBA-ordered queues (async / scrub / initializing), issue the
 836          * i/o which follows the most recently issued i/o in LBA (offset) order.
 837          *
 838          * For FIFO queues (sync/trim), issue the i/o with the lowest timestamp.
 839          */
 840         tree = vdev_queue_class_tree(vq, p);
 841         vq->vq_io_search.io_timestamp = 0;
 842         vq->vq_io_search.io_offset = vq->vq_last_offset - 1;
 843         VERIFY3P(avl_find(tree, &vq->vq_io_search, &idx), ==, NULL);
 844         zio = avl_nearest(tree, idx, AVL_AFTER);
 845         if (zio == NULL)
 846                 zio = avl_first(tree);
 847         ASSERT3U(zio->io_priority, ==, p);
 848
 849         aio = vdev_queue_aggregate(vq, zio);
 850         if (aio != NULL)
 851                 zio = aio;
 852         else
 853                 vdev_queue_io_remove(vq, zio);
 854
 855         /*
 856          * If the I/O is or was optional and therefore has no data, we need to
 857          * simply discard it. We need to drop the vdev queue's lock to avoid a
 858          * deadlock that we could encounter since this I/O will complete
 859          * immediately.
 860          */
 861         if (zio->io_flags & ZIO_FLAG_NODATA) {
 862                 mutex_exit(&vq->vq_lock);
 863                 zio_vdev_io_bypass(zio);
 864                 zio_execute(zio);
 865                 mutex_enter(&vq->vq_lock);
 866                 goto again;
 867         }
 868
 869         vdev_queue_pending_add(vq, zio);
 870         vq->vq_last_offset = zio->io_offset + zio->io_size;
 871
 872         return (zio);
 873 }
 874
 875 zio_t *
 876 vdev_queue_io(zio_t *zio)
 877 {
 878         vdev_queue_t *vq = &zio->io_vd->vdev_queue;
 879         zio_t *nio;
 880
 881         if (zio->io_flags & ZIO_FLAG_DONT_QUEUE)
 882                 return (zio);
 883
 884         /*
 885          * Children i/os inherent their parent's priority, which might
 886          * not match the child's i/o type.  Fix it up here.
 887          */
 888         if (zio->io_type == ZIO_TYPE_READ) {
 889                 ASSERT(zio->io_priority != ZIO_PRIORITY_TRIM);
 890
 891                 if (zio->io_priority != ZIO_PRIORITY_SYNC_READ &&
 892                     zio->io_priority != ZIO_PRIORITY_ASYNC_READ &&
 893                     zio->io_priority != ZIO_PRIORITY_SCRUB &&
 894                     zio->io_priority != ZIO_PRIORITY_REMOVAL &&
 895                     zio->io_priority != ZIO_PRIORITY_INITIALIZING &&
 896                     zio->io_priority != ZIO_PRIORITY_REBUILD) {
 897                         zio->io_priority = ZIO_PRIORITY_ASYNC_READ;
 898                 }
 899         } else if (zio->io_type == ZIO_TYPE_WRITE) {
 900                 ASSERT(zio->io_priority != ZIO_PRIORITY_TRIM);
 901
 902                 if (zio->io_priority != ZIO_PRIORITY_SYNC_WRITE &&
 903                     zio->io_priority != ZIO_PRIORITY_ASYNC_WRITE &&
 904                     zio->io_priority != ZIO_PRIORITY_REMOVAL &&
 905                     zio->io_priority != ZIO_PRIORITY_INITIALIZING &&
 906                     zio->io_priority != ZIO_PRIORITY_REBUILD) {
 907                         zio->io_priority = ZIO_PRIORITY_ASYNC_WRITE;
 908                 }
 909         } else {
 910                 ASSERT(zio->io_type == ZIO_TYPE_TRIM);
 911                 ASSERT(zio->io_priority == ZIO_PRIORITY_TRIM);
 912         }
 913
 914         zio->io_flags |= ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_QUEUE;
 915         zio->io_timestamp = gethrtime();
 916
 917         mutex_enter(&vq->vq_lock);
 918         vdev_queue_io_add(vq, zio);
 919         nio = vdev_queue_io_to_issue(vq);
 920         mutex_exit(&vq->vq_lock);
 921
 922         if (nio == NULL)
 923                 return (NULL);
 924
 925         if (nio->io_done == vdev_queue_agg_io_done) {
 926                 zio_nowait(nio);
 927                 return (NULL);
 928         }
 929
 930         return (nio);
 931 }
 932
 933 void
 934 vdev_queue_io_done(zio_t *zio)
 935 {
 936         vdev_queue_t *vq = &zio->io_vd->vdev_queue;
 937         zio_t *nio;
 938
 939         hrtime_t now = gethrtime();
 940         vq->vq_io_complete_ts = now;
 941         vq->vq_io_delta_ts = zio->io_delta = now - zio->io_timestamp;
 942
 943         mutex_enter(&vq->vq_lock);
 944         vdev_queue_pending_remove(vq, zio);
 945
 946         while ((nio = vdev_queue_io_to_issue(vq)) != NULL) {
 947                 mutex_exit(&vq->vq_lock);
 948                 if (nio->io_done == vdev_queue_agg_io_done) {
 949                         zio_nowait(nio);
 950                 } else {
 951                         zio_vdev_io_reissue(nio);
 952                         zio_execute(nio);
 953                 }
 954                 mutex_enter(&vq->vq_lock);
 955         }
 956
 957         mutex_exit(&vq->vq_lock);
 958 }
 959
 960 void
 961 vdev_queue_change_io_priority(zio_t *zio, zio_priority_t priority)
 962 {
 963         vdev_queue_t *vq = &zio->io_vd->vdev_queue;
 964         avl_tree_t *tree;
 965
 966         /*
 967          * ZIO_PRIORITY_NOW is used by the vdev cache code and the aggregate zio
 968          * code to issue IOs without adding them to the vdev queue. In this
 969          * case, the zio is already going to be issued as quickly as possible
 970          * and so it doesn't need any reprioritization to help.
 971          */
 972         if (zio->io_priority == ZIO_PRIORITY_NOW)
 973                 return;
 974
 975         ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE);
 976         ASSERT3U(priority, <, ZIO_PRIORITY_NUM_QUEUEABLE);
 977
 978         if (zio->io_type == ZIO_TYPE_READ) {
 979                 if (priority != ZIO_PRIORITY_SYNC_READ &&
 980                     priority != ZIO_PRIORITY_ASYNC_READ &&
 981                     priority != ZIO_PRIORITY_SCRUB)
 982                         priority = ZIO_PRIORITY_ASYNC_READ;
 983         } else {
 984                 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
 985                 if (priority != ZIO_PRIORITY_SYNC_WRITE &&
 986                     priority != ZIO_PRIORITY_ASYNC_WRITE)
 987                         priority = ZIO_PRIORITY_ASYNC_WRITE;
 988         }
 989
 990         mutex_enter(&vq->vq_lock);
 991
 992         /*
 993          * If the zio is in none of the queues we can simply change
 994          * the priority. If the zio is waiting to be submitted we must
 995          * remove it from the queue and re-insert it with the new priority.
 996          * Otherwise, the zio is currently active and we cannot change its
 997          * priority.
 998          */
 999         tree = vdev_queue_class_tree(vq, zio->io_priority);
1000         if (avl_find(tree, zio, NULL) == zio) {
1001                 avl_remove(vdev_queue_class_tree(vq, zio->io_priority), zio);
1002                 zio->io_priority = priority;
1003                 avl_add(vdev_queue_class_tree(vq, zio->io_priority), zio);
1004         } else if (avl_find(&vq->vq_active_tree, zio, NULL) != zio) {
1005                 zio->io_priority = priority;
1006         }
1007
1008         mutex_exit(&vq->vq_lock);
1009 }
1010
1011 /*
1012  * As these two methods are only used for load calculations we're not
1013  * concerned if we get an incorrect value on 32bit platforms due to lack of
1014  * vq_lock mutex use here, instead we prefer to keep it lock free for
1015  * performance.
1016  */
1017 int
1018 vdev_queue_length(vdev_t *vd)
1019 {
1020         return (avl_numnodes(&vd->vdev_queue.vq_active_tree));
1021 }
1022
1023 uint64_t
1024 vdev_queue_last_offset(vdev_t *vd)
1025 {
1026         return (vd->vdev_queue.vq_last_offset);
1027 }
1028
1029 /* BEGIN CSTYLED */
1030 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, aggregation_limit, INT, ZMOD_RW,
1031         "Max vdev I/O aggregation size");
1032
1033 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, aggregation_limit_non_rotating, INT, ZMOD_RW,
1034         "Max vdev I/O aggregation size for non-rotating media");
1035
1036 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, aggregate_trim, INT, ZMOD_RW,
1037         "Allow TRIM I/O to be aggregated");
1038
1039 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, read_gap_limit, INT, ZMOD_RW,
1040         "Aggregate read I/O over gap");
1041
1042 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, write_gap_limit, INT, ZMOD_RW,
1043         "Aggregate write I/O over gap");
1044
1045 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, max_active, INT, ZMOD_RW,
1046         "Maximum number of active I/Os per vdev");
1047
1048 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_write_active_max_dirty_percent, INT, ZMOD_RW,
1049         "Async write concurrency max threshold");
1050
1051 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_write_active_min_dirty_percent, INT, ZMOD_RW,
1052         "Async write concurrency min threshold");
1053
1054 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_read_max_active, INT, ZMOD_RW,
1055         "Max active async read I/Os per vdev");
1056
1057 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_read_min_active, INT, ZMOD_RW,
1058         "Min active async read I/Os per vdev");
1059
1060 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_write_max_active, INT, ZMOD_RW,
1061         "Max active async write I/Os per vdev");
1062
1063 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_write_min_active, INT, ZMOD_RW,
1064         "Min active async write I/Os per vdev");
1065
1066 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, initializing_max_active, INT, ZMOD_RW,
1067         "Max active initializing I/Os per vdev");
1068
1069 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, initializing_min_active, INT, ZMOD_RW,
1070         "Min active initializing I/Os per vdev");
1071
1072 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, removal_max_active, INT, ZMOD_RW,
1073         "Max active removal I/Os per vdev");
1074
1075 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, removal_min_active, INT, ZMOD_RW,
1076         "Min active removal I/Os per vdev");
1077
1078 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, scrub_max_active, INT, ZMOD_RW,
1079         "Max active scrub I/Os per vdev");
1080
1081 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, scrub_min_active, INT, ZMOD_RW,
1082         "Min active scrub I/Os per vdev");
1083
1084 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, sync_read_max_active, INT, ZMOD_RW,
1085         "Max active sync read I/Os per vdev");
1086
1087 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, sync_read_min_active, INT, ZMOD_RW,
1088         "Min active sync read I/Os per vdev");
1089
1090 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, sync_write_max_active, INT, ZMOD_RW,
1091         "Max active sync write I/Os per vdev");
1092
1093 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, sync_write_min_active, INT, ZMOD_RW,
1094         "Min active sync write I/Os per vdev");
1095
1096 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, trim_max_active, INT, ZMOD_RW,
1097         "Max active trim/discard I/Os per vdev");
1098
1099 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, trim_min_active, INT, ZMOD_RW,
1100         "Min active trim/discard I/Os per vdev");
1101
1102 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, rebuild_max_active, INT, ZMOD_RW,
1103         "Max active rebuild I/Os per vdev");
1104
1105 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, rebuild_min_active, INT, ZMOD_RW,
1106         "Min active rebuild I/Os per vdev");
1107
1108 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, nia_credit, INT, ZMOD_RW,
1109         "Number of non-interactive I/Os to allow in sequence");
1110
1111 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, nia_delay, INT, ZMOD_RW,
1112         "Number of non-interactive I/Os before _max_active");
1113
1114 ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, queue_depth_pct, INT, ZMOD_RW,
1115         "Queue depth percentage for each top-level vdev");
1116 /* END CSTYLED */