diff options
Diffstat (limited to 'sys/contrib/openzfs/module/zfs/vdev_queue.c')
| -rw-r--r-- | sys/contrib/openzfs/module/zfs/vdev_queue.c | 1145 |
1 files changed, 1145 insertions, 0 deletions
diff --git a/sys/contrib/openzfs/module/zfs/vdev_queue.c b/sys/contrib/openzfs/module/zfs/vdev_queue.c new file mode 100644 index 000000000000..c12713b107bf --- /dev/null +++ b/sys/contrib/openzfs/module/zfs/vdev_queue.c @@ -0,0 +1,1145 @@ +// SPDX-License-Identifier: CDDL-1.0 +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or https://opensource.org/licenses/CDDL-1.0. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* + * Copyright 2009 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +/* + * Copyright (c) 2012, 2018 by Delphix. All rights reserved. + */ + +#include <sys/zfs_context.h> +#include <sys/vdev_impl.h> +#include <sys/spa_impl.h> +#include <sys/zio.h> +#include <sys/avl.h> +#include <sys/dsl_pool.h> +#include <sys/metaslab_impl.h> +#include <sys/spa.h> +#include <sys/abd.h> + +/* + * ZFS I/O Scheduler + * --------------- + * + * ZFS issues I/O operations to leaf vdevs to satisfy and complete zios. The + * I/O scheduler determines when and in what order those operations are + * issued. The I/O scheduler divides operations into five I/O classes + * prioritized in the following order: sync read, sync write, async read, + * async write, and scrub/resilver. Each queue defines the minimum and + * maximum number of concurrent operations that may be issued to the device. + * In addition, the device has an aggregate maximum. Note that the sum of the + * per-queue minimums must not exceed the aggregate maximum. If the + * sum of the per-queue maximums exceeds the aggregate maximum, then the + * number of active i/os may reach zfs_vdev_max_active, in which case no + * further i/os will be issued regardless of whether all per-queue + * minimums have been met. + * + * For many physical devices, throughput increases with the number of + * concurrent operations, but latency typically suffers. Further, physical + * devices typically have a limit at which more concurrent operations have no + * effect on throughput or can actually cause it to decrease. + * + * The scheduler selects the next operation to issue by first looking for an + * I/O class whose minimum has not been satisfied. Once all are satisfied and + * the aggregate maximum has not been hit, the scheduler looks for classes + * whose maximum has not been satisfied. Iteration through the I/O classes is + * done in the order specified above. No further operations are issued if the + * aggregate maximum number of concurrent operations has been hit or if there + * are no operations queued for an I/O class that has not hit its maximum. + * Every time an i/o is queued or an operation completes, the I/O scheduler + * looks for new operations to issue. + * + * All I/O classes have a fixed maximum number of outstanding operations + * except for the async write class. Asynchronous writes represent the data + * that is committed to stable storage during the syncing stage for + * transaction groups (see txg.c). Transaction groups enter the syncing state + * periodically so the number of queued async writes will quickly burst up and + * then bleed down to zero. Rather than servicing them as quickly as possible, + * the I/O scheduler changes the maximum number of active async write i/os + * according to the amount of dirty data in the pool (see dsl_pool.c). Since + * both throughput and latency typically increase with the number of + * concurrent operations issued to physical devices, reducing the burstiness + * in the number of concurrent operations also stabilizes the response time of + * operations from other -- and in particular synchronous -- queues. In broad + * strokes, the I/O scheduler will issue more concurrent operations from the + * async write queue as there's more dirty data in the pool. + * + * Async Writes + * + * The number of concurrent operations issued for the async write I/O class + * follows a piece-wise linear function defined by a few adjustable points. + * + * | o---------| <-- zfs_vdev_async_write_max_active + * ^ | /^ | + * | | / | | + * active | / | | + * I/O | / | | + * count | / | | + * | / | | + * |------------o | | <-- zfs_vdev_async_write_min_active + * 0|____________^______|_________| + * 0% | | 100% of zfs_dirty_data_max + * | | + * | `-- zfs_vdev_async_write_active_max_dirty_percent + * `--------- zfs_vdev_async_write_active_min_dirty_percent + * + * Until the amount of dirty data exceeds a minimum percentage of the dirty + * data allowed in the pool, the I/O scheduler will limit the number of + * concurrent operations to the minimum. As that threshold is crossed, the + * number of concurrent operations issued increases linearly to the maximum at + * the specified maximum percentage of the dirty data allowed in the pool. + * + * Ideally, the amount of dirty data on a busy pool will stay in the sloped + * part of the function between zfs_vdev_async_write_active_min_dirty_percent + * and zfs_vdev_async_write_active_max_dirty_percent. If it exceeds the + * maximum percentage, this indicates that the rate of incoming data is + * greater than the rate that the backend storage can handle. In this case, we + * must further throttle incoming writes (see dmu_tx_delay() for details). + */ + +/* + * The maximum number of i/os active to each device. Ideally, this will be >= + * the sum of each queue's max_active. + */ +uint_t zfs_vdev_max_active = 1000; + +/* + * Per-queue limits on the number of i/os active to each device. If the + * number of active i/os is < zfs_vdev_max_active, then the min_active comes + * into play. We will send min_active from each queue round-robin, and then + * send from queues in the order defined by zio_priority_t up to max_active. + * Some queues have additional mechanisms to limit number of active I/Os in + * addition to min_active and max_active, see below. + * + * In general, smaller max_active's will lead to lower latency of synchronous + * operations. Larger max_active's may lead to higher overall throughput, + * depending on underlying storage. + * + * The ratio of the queues' max_actives determines the balance of performance + * between reads, writes, and scrubs. E.g., increasing + * zfs_vdev_scrub_max_active will cause the scrub or resilver to complete + * more quickly, but reads and writes to have higher latency and lower + * throughput. + */ +static uint_t zfs_vdev_sync_read_min_active = 10; +static uint_t zfs_vdev_sync_read_max_active = 10; +static uint_t zfs_vdev_sync_write_min_active = 10; +static uint_t zfs_vdev_sync_write_max_active = 10; +static uint_t zfs_vdev_async_read_min_active = 1; +/* */ uint_t zfs_vdev_async_read_max_active = 3; +static uint_t zfs_vdev_async_write_min_active = 2; +static uint_t zfs_vdev_async_write_max_active = 10; +static uint_t zfs_vdev_scrub_min_active = 1; +static uint_t zfs_vdev_scrub_max_active = 3; +static uint_t zfs_vdev_removal_min_active = 1; +static uint_t zfs_vdev_removal_max_active = 2; +static uint_t zfs_vdev_initializing_min_active = 1; +static uint_t zfs_vdev_initializing_max_active = 1; +static uint_t zfs_vdev_trim_min_active = 1; +static uint_t zfs_vdev_trim_max_active = 2; +static uint_t zfs_vdev_rebuild_min_active = 1; +static uint_t zfs_vdev_rebuild_max_active = 3; + +/* + * When the pool has less than zfs_vdev_async_write_active_min_dirty_percent + * dirty data, use zfs_vdev_async_write_min_active. When it has more than + * zfs_vdev_async_write_active_max_dirty_percent, use + * zfs_vdev_async_write_max_active. The value is linearly interpolated + * between min and max. + */ +uint_t zfs_vdev_async_write_active_min_dirty_percent = 30; +uint_t zfs_vdev_async_write_active_max_dirty_percent = 60; + +/* + * For non-interactive I/O (scrub, resilver, removal, initialize and rebuild), + * the number of concurrently-active I/O's is limited to *_min_active, unless + * the vdev is "idle". When there are no interactive I/Os active (sync or + * async), and zfs_vdev_nia_delay I/Os have completed since the last + * interactive I/O, then the vdev is considered to be "idle", and the number + * of concurrently-active non-interactive I/O's is increased to *_max_active. + */ +static uint_t zfs_vdev_nia_delay = 5; + +/* + * Some HDDs tend to prioritize sequential I/O so high that concurrent + * random I/O latency reaches several seconds. On some HDDs it happens + * even if sequential I/Os are submitted one at a time, and so setting + * *_max_active to 1 does not help. To prevent non-interactive I/Os, like + * scrub, from monopolizing the device no more than zfs_vdev_nia_credit + * I/Os can be sent while there are outstanding incomplete interactive + * I/Os. This enforced wait ensures the HDD services the interactive I/O + * within a reasonable amount of time. + */ +static uint_t zfs_vdev_nia_credit = 5; + +/* + * To reduce IOPs, we aggregate small adjacent I/Os into one large I/O. + * For read I/Os, we also aggregate across small adjacency gaps; for writes + * we include spans of optional I/Os to aid aggregation at the disk even when + * they aren't able to help us aggregate at this level. + */ +static uint_t zfs_vdev_aggregation_limit = 1 << 20; +static uint_t zfs_vdev_aggregation_limit_non_rotating = SPA_OLD_MAXBLOCKSIZE; +static uint_t zfs_vdev_read_gap_limit = 32 << 10; +static uint_t zfs_vdev_write_gap_limit = 4 << 10; + +static int +vdev_queue_offset_compare(const void *x1, const void *x2) +{ + const zio_t *z1 = (const zio_t *)x1; + const zio_t *z2 = (const zio_t *)x2; + + int cmp = TREE_CMP(z1->io_offset, z2->io_offset); + + if (likely(cmp)) + return (cmp); + + return (TREE_PCMP(z1, z2)); +} + +#define VDQ_T_SHIFT 29 + +static int +vdev_queue_to_compare(const void *x1, const void *x2) +{ + const zio_t *z1 = (const zio_t *)x1; + const zio_t *z2 = (const zio_t *)x2; + + int tcmp = TREE_CMP(z1->io_timestamp >> VDQ_T_SHIFT, + z2->io_timestamp >> VDQ_T_SHIFT); + int ocmp = TREE_CMP(z1->io_offset, z2->io_offset); + int cmp = tcmp ? tcmp : ocmp; + + if (likely(cmp | (z1->io_queue_state == ZIO_QS_NONE))) + return (cmp); + + return (TREE_PCMP(z1, z2)); +} + +static inline boolean_t +vdev_queue_class_fifo(zio_priority_t p) +{ + return (p == ZIO_PRIORITY_SYNC_READ || p == ZIO_PRIORITY_SYNC_WRITE || + p == ZIO_PRIORITY_TRIM); +} + +static void +vdev_queue_class_add(vdev_queue_t *vq, zio_t *zio) +{ + zio_priority_t p = zio->io_priority; + vq->vq_cqueued |= 1U << p; + if (vdev_queue_class_fifo(p)) { + list_insert_tail(&vq->vq_class[p].vqc_list, zio); + vq->vq_class[p].vqc_list_numnodes++; + } + else + avl_add(&vq->vq_class[p].vqc_tree, zio); +} + +static void +vdev_queue_class_remove(vdev_queue_t *vq, zio_t *zio) +{ + zio_priority_t p = zio->io_priority; + uint32_t empty; + if (vdev_queue_class_fifo(p)) { + list_t *list = &vq->vq_class[p].vqc_list; + list_remove(list, zio); + empty = list_is_empty(list); + vq->vq_class[p].vqc_list_numnodes--; + } else { + avl_tree_t *tree = &vq->vq_class[p].vqc_tree; + avl_remove(tree, zio); + empty = avl_is_empty(tree); + } + vq->vq_cqueued &= ~(empty << p); +} + +static uint_t +vdev_queue_class_min_active(vdev_queue_t *vq, zio_priority_t p) +{ + switch (p) { + case ZIO_PRIORITY_SYNC_READ: + return (zfs_vdev_sync_read_min_active); + case ZIO_PRIORITY_SYNC_WRITE: + return (zfs_vdev_sync_write_min_active); + case ZIO_PRIORITY_ASYNC_READ: + return (zfs_vdev_async_read_min_active); + case ZIO_PRIORITY_ASYNC_WRITE: + return (zfs_vdev_async_write_min_active); + case ZIO_PRIORITY_SCRUB: + return (vq->vq_ia_active == 0 ? zfs_vdev_scrub_min_active : + MIN(vq->vq_nia_credit, zfs_vdev_scrub_min_active)); + case ZIO_PRIORITY_REMOVAL: + return (vq->vq_ia_active == 0 ? zfs_vdev_removal_min_active : + MIN(vq->vq_nia_credit, zfs_vdev_removal_min_active)); + case ZIO_PRIORITY_INITIALIZING: + return (vq->vq_ia_active == 0 ?zfs_vdev_initializing_min_active: + MIN(vq->vq_nia_credit, zfs_vdev_initializing_min_active)); + case ZIO_PRIORITY_TRIM: + return (zfs_vdev_trim_min_active); + case ZIO_PRIORITY_REBUILD: + return (vq->vq_ia_active == 0 ? zfs_vdev_rebuild_min_active : + MIN(vq->vq_nia_credit, zfs_vdev_rebuild_min_active)); + default: + panic("invalid priority %u", p); + return (0); + } +} + +static uint_t +vdev_queue_max_async_writes(spa_t *spa) +{ + uint_t writes; + uint64_t dirty = 0; + dsl_pool_t *dp = spa_get_dsl(spa); + uint64_t min_bytes = zfs_dirty_data_max * + zfs_vdev_async_write_active_min_dirty_percent / 100; + uint64_t max_bytes = zfs_dirty_data_max * + zfs_vdev_async_write_active_max_dirty_percent / 100; + + /* + * Async writes may occur before the assignment of the spa's + * dsl_pool_t if a self-healing zio is issued prior to the + * completion of dmu_objset_open_impl(). + */ + if (dp == NULL) + return (zfs_vdev_async_write_max_active); + + /* + * Sync tasks correspond to interactive user actions. To reduce the + * execution time of those actions we push data out as fast as possible. + */ + dirty = dp->dp_dirty_total; + if (dirty > max_bytes || spa_has_pending_synctask(spa)) + return (zfs_vdev_async_write_max_active); + + if (dirty < min_bytes) + return (zfs_vdev_async_write_min_active); + + /* + * linear interpolation: + * slope = (max_writes - min_writes) / (max_bytes - min_bytes) + * move right by min_bytes + * move up by min_writes + */ + writes = (dirty - min_bytes) * + (zfs_vdev_async_write_max_active - + zfs_vdev_async_write_min_active) / + (max_bytes - min_bytes) + + zfs_vdev_async_write_min_active; + ASSERT3U(writes, >=, zfs_vdev_async_write_min_active); + ASSERT3U(writes, <=, zfs_vdev_async_write_max_active); + return (writes); +} + +static uint_t +vdev_queue_class_max_active(vdev_queue_t *vq, zio_priority_t p) +{ + switch (p) { + case ZIO_PRIORITY_SYNC_READ: + return (zfs_vdev_sync_read_max_active); + case ZIO_PRIORITY_SYNC_WRITE: + return (zfs_vdev_sync_write_max_active); + case ZIO_PRIORITY_ASYNC_READ: + return (zfs_vdev_async_read_max_active); + case ZIO_PRIORITY_ASYNC_WRITE: + return (vdev_queue_max_async_writes(vq->vq_vdev->vdev_spa)); + case ZIO_PRIORITY_SCRUB: + if (vq->vq_ia_active > 0) { + return (MIN(vq->vq_nia_credit, + zfs_vdev_scrub_min_active)); + } else if (vq->vq_nia_credit < zfs_vdev_nia_delay) + return (MAX(1, zfs_vdev_scrub_min_active)); + return (zfs_vdev_scrub_max_active); + case ZIO_PRIORITY_REMOVAL: + if (vq->vq_ia_active > 0) { + return (MIN(vq->vq_nia_credit, + zfs_vdev_removal_min_active)); + } else if (vq->vq_nia_credit < zfs_vdev_nia_delay) + return (MAX(1, zfs_vdev_removal_min_active)); + return (zfs_vdev_removal_max_active); + case ZIO_PRIORITY_INITIALIZING: + if (vq->vq_ia_active > 0) { + return (MIN(vq->vq_nia_credit, + zfs_vdev_initializing_min_active)); + } else if (vq->vq_nia_credit < zfs_vdev_nia_delay) + return (MAX(1, zfs_vdev_initializing_min_active)); + return (zfs_vdev_initializing_max_active); + case ZIO_PRIORITY_TRIM: + return (zfs_vdev_trim_max_active); + case ZIO_PRIORITY_REBUILD: + if (vq->vq_ia_active > 0) { + return (MIN(vq->vq_nia_credit, + zfs_vdev_rebuild_min_active)); + } else if (vq->vq_nia_credit < zfs_vdev_nia_delay) + return (MAX(1, zfs_vdev_rebuild_min_active)); + return (zfs_vdev_rebuild_max_active); + default: + panic("invalid priority %u", p); + return (0); + } +} + +/* + * Return the i/o class to issue from, or ZIO_PRIORITY_NUM_QUEUEABLE if + * there is no eligible class. + */ +static zio_priority_t +vdev_queue_class_to_issue(vdev_queue_t *vq) +{ + uint32_t cq = vq->vq_cqueued; + zio_priority_t p, p1; + + if (cq == 0 || vq->vq_active >= zfs_vdev_max_active) + return (ZIO_PRIORITY_NUM_QUEUEABLE); + + /* + * Find a queue that has not reached its minimum # outstanding i/os. + * Do round-robin to reduce starvation due to zfs_vdev_max_active + * and vq_nia_credit limits. + */ + p1 = vq->vq_last_prio + 1; + if (p1 >= ZIO_PRIORITY_NUM_QUEUEABLE) + p1 = 0; + for (p = p1; p < ZIO_PRIORITY_NUM_QUEUEABLE; p++) { + if ((cq & (1U << p)) != 0 && vq->vq_cactive[p] < + vdev_queue_class_min_active(vq, p)) + goto found; + } + for (p = 0; p < p1; p++) { + if ((cq & (1U << p)) != 0 && vq->vq_cactive[p] < + vdev_queue_class_min_active(vq, p)) + goto found; + } + + /* + * If we haven't found a queue, look for one that hasn't reached its + * maximum # outstanding i/os. + */ + for (p = 0; p < ZIO_PRIORITY_NUM_QUEUEABLE; p++) { + if ((cq & (1U << p)) != 0 && vq->vq_cactive[p] < + vdev_queue_class_max_active(vq, p)) + break; + } + +found: + vq->vq_last_prio = p; + return (p); +} + +void +vdev_queue_init(vdev_t *vd) +{ + vdev_queue_t *vq = &vd->vdev_queue; + zio_priority_t p; + + vq->vq_vdev = vd; + + for (p = 0; p < ZIO_PRIORITY_NUM_QUEUEABLE; p++) { + if (vdev_queue_class_fifo(p)) { + list_create(&vq->vq_class[p].vqc_list, + sizeof (zio_t), + offsetof(struct zio, io_queue_node.l)); + } else { + avl_create(&vq->vq_class[p].vqc_tree, + vdev_queue_to_compare, sizeof (zio_t), + offsetof(struct zio, io_queue_node.a)); + } + } + avl_create(&vq->vq_read_offset_tree, + vdev_queue_offset_compare, sizeof (zio_t), + offsetof(struct zio, io_offset_node)); + avl_create(&vq->vq_write_offset_tree, + vdev_queue_offset_compare, sizeof (zio_t), + offsetof(struct zio, io_offset_node)); + + vq->vq_last_offset = 0; + list_create(&vq->vq_active_list, sizeof (struct zio), + offsetof(struct zio, io_queue_node.l)); + mutex_init(&vq->vq_lock, NULL, MUTEX_DEFAULT, NULL); +} + +void +vdev_queue_fini(vdev_t *vd) +{ + vdev_queue_t *vq = &vd->vdev_queue; + + for (zio_priority_t p = 0; p < ZIO_PRIORITY_NUM_QUEUEABLE; p++) { + if (vdev_queue_class_fifo(p)) + list_destroy(&vq->vq_class[p].vqc_list); + else + avl_destroy(&vq->vq_class[p].vqc_tree); + } + avl_destroy(&vq->vq_read_offset_tree); + avl_destroy(&vq->vq_write_offset_tree); + + list_destroy(&vq->vq_active_list); + mutex_destroy(&vq->vq_lock); +} + +static void +vdev_queue_io_add(vdev_queue_t *vq, zio_t *zio) +{ + zio->io_queue_state = ZIO_QS_QUEUED; + vdev_queue_class_add(vq, zio); + if (zio->io_type == ZIO_TYPE_READ) + avl_add(&vq->vq_read_offset_tree, zio); + else if (zio->io_type == ZIO_TYPE_WRITE) + avl_add(&vq->vq_write_offset_tree, zio); +} + +static void +vdev_queue_io_remove(vdev_queue_t *vq, zio_t *zio) +{ + vdev_queue_class_remove(vq, zio); + if (zio->io_type == ZIO_TYPE_READ) + avl_remove(&vq->vq_read_offset_tree, zio); + else if (zio->io_type == ZIO_TYPE_WRITE) + avl_remove(&vq->vq_write_offset_tree, zio); + zio->io_queue_state = ZIO_QS_NONE; +} + +static boolean_t +vdev_queue_is_interactive(zio_priority_t p) +{ + switch (p) { + case ZIO_PRIORITY_SCRUB: + case ZIO_PRIORITY_REMOVAL: + case ZIO_PRIORITY_INITIALIZING: + case ZIO_PRIORITY_REBUILD: + return (B_FALSE); + default: + return (B_TRUE); + } +} + +static void +vdev_queue_pending_add(vdev_queue_t *vq, zio_t *zio) +{ + ASSERT(MUTEX_HELD(&vq->vq_lock)); + ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE); + vq->vq_cactive[zio->io_priority]++; + vq->vq_active++; + if (vdev_queue_is_interactive(zio->io_priority)) { + if (++vq->vq_ia_active == 1) + vq->vq_nia_credit = 1; + } else if (vq->vq_ia_active > 0) { + vq->vq_nia_credit--; + } + zio->io_queue_state = ZIO_QS_ACTIVE; + list_insert_tail(&vq->vq_active_list, zio); +} + +static void +vdev_queue_pending_remove(vdev_queue_t *vq, zio_t *zio) +{ + ASSERT(MUTEX_HELD(&vq->vq_lock)); + ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE); + vq->vq_cactive[zio->io_priority]--; + vq->vq_active--; + if (vdev_queue_is_interactive(zio->io_priority)) { + if (--vq->vq_ia_active == 0) + vq->vq_nia_credit = 0; + else + vq->vq_nia_credit = zfs_vdev_nia_credit; + } else if (vq->vq_ia_active == 0) + vq->vq_nia_credit++; + list_remove(&vq->vq_active_list, zio); + zio->io_queue_state = ZIO_QS_NONE; +} + +static void +vdev_queue_agg_io_done(zio_t *aio) +{ + abd_free(aio->io_abd); +} + +/* + * Compute the range spanned by two i/os, which is the endpoint of the last + * (lio->io_offset + lio->io_size) minus start of the first (fio->io_offset). + * Conveniently, the gap between fio and lio is given by -IO_SPAN(lio, fio); + * thus fio and lio are adjacent if and only if IO_SPAN(lio, fio) == 0. + */ +#define IO_SPAN(fio, lio) ((lio)->io_offset + (lio)->io_size - (fio)->io_offset) +#define IO_GAP(fio, lio) (-IO_SPAN(lio, fio)) + +/* + * Sufficiently adjacent io_offset's in ZIOs will be aggregated. We do this + * by creating a gang ABD from the adjacent ZIOs io_abd's. By using + * a gang ABD we avoid doing memory copies to and from the parent, + * child ZIOs. The gang ABD also accounts for gaps between adjacent + * io_offsets by simply getting the zero ABD for writes or allocating + * a new ABD for reads and placing them in the gang ABD as well. + */ +static zio_t * +vdev_queue_aggregate(vdev_queue_t *vq, zio_t *zio) +{ + zio_t *first, *last, *aio, *dio, *mandatory, *nio; + uint64_t maxgap = 0; + uint64_t size; + uint64_t limit; + boolean_t stretch = B_FALSE; + uint64_t next_offset; + abd_t *abd; + avl_tree_t *t; + + /* + * TRIM aggregation should not be needed since code in zfs_trim.c can + * submit TRIM I/O for extents up to zfs_trim_extent_bytes_max (128M). + */ + if (zio->io_type == ZIO_TYPE_TRIM) + return (NULL); + + if (zio->io_flags & ZIO_FLAG_DONT_AGGREGATE) + return (NULL); + + if (vq->vq_vdev->vdev_nonrot) + limit = zfs_vdev_aggregation_limit_non_rotating; + else + limit = zfs_vdev_aggregation_limit; + if (limit == 0) + return (NULL); + limit = MIN(limit, SPA_MAXBLOCKSIZE); + + /* + * I/Os to distributed spares are directly dispatched to the dRAID + * leaf vdevs for aggregation. See the comment at the end of the + * zio_vdev_io_start() function. + */ + ASSERT(vq->vq_vdev->vdev_ops != &vdev_draid_spare_ops); + + first = last = zio; + + if (zio->io_type == ZIO_TYPE_READ) { + maxgap = zfs_vdev_read_gap_limit; + t = &vq->vq_read_offset_tree; + } else { + ASSERT3U(zio->io_type, ==, ZIO_TYPE_WRITE); + t = &vq->vq_write_offset_tree; + } + + /* + * We can aggregate I/Os that are sufficiently adjacent and of + * the same flavor, as expressed by the AGG_INHERIT flags. + * The latter requirement is necessary so that certain + * attributes of the I/O, such as whether it's a normal I/O + * or a scrub/resilver, can be preserved in the aggregate. + * We can include optional I/Os, but don't allow them + * to begin a range as they add no benefit in that situation. + */ + + /* + * We keep track of the last non-optional I/O. + */ + mandatory = (first->io_flags & ZIO_FLAG_OPTIONAL) ? NULL : first; + + /* + * Walk backwards through sufficiently contiguous I/Os + * recording the last non-optional I/O. + */ + zio_flag_t flags = zio->io_flags & ZIO_FLAG_AGG_INHERIT; + while ((dio = AVL_PREV(t, first)) != NULL && + (dio->io_flags & ZIO_FLAG_AGG_INHERIT) == flags && + IO_SPAN(dio, last) <= limit && + IO_GAP(dio, first) <= maxgap && + dio->io_type == zio->io_type) { + first = dio; + if (mandatory == NULL && !(first->io_flags & ZIO_FLAG_OPTIONAL)) + mandatory = first; + } + + /* + * Skip any initial optional I/Os. + */ + while ((first->io_flags & ZIO_FLAG_OPTIONAL) && first != last) { + first = AVL_NEXT(t, first); + ASSERT(first != NULL); + } + + + /* + * Walk forward through sufficiently contiguous I/Os. + * The aggregation limit does not apply to optional i/os, so that + * we can issue contiguous writes even if they are larger than the + * aggregation limit. + */ + while ((dio = AVL_NEXT(t, last)) != NULL && + (dio->io_flags & ZIO_FLAG_AGG_INHERIT) == flags && + (IO_SPAN(first, dio) <= limit || + (dio->io_flags & ZIO_FLAG_OPTIONAL)) && + IO_SPAN(first, dio) <= SPA_MAXBLOCKSIZE && + IO_GAP(last, dio) <= maxgap && + dio->io_type == zio->io_type) { + last = dio; + if (!(last->io_flags & ZIO_FLAG_OPTIONAL)) + mandatory = last; + } + + /* + * Now that we've established the range of the I/O aggregation + * we must decide what to do with trailing optional I/Os. + * For reads, there's nothing to do. While we are unable to + * aggregate further, it's possible that a trailing optional + * I/O would allow the underlying device to aggregate with + * subsequent I/Os. We must therefore determine if the next + * non-optional I/O is close enough to make aggregation + * worthwhile. + */ + if (zio->io_type == ZIO_TYPE_WRITE && mandatory != NULL) { + zio_t *nio = last; + while ((dio = AVL_NEXT(t, nio)) != NULL && + IO_GAP(nio, dio) == 0 && + IO_GAP(mandatory, dio) <= zfs_vdev_write_gap_limit) { + nio = dio; + if (!(nio->io_flags & ZIO_FLAG_OPTIONAL)) { + stretch = B_TRUE; + break; + } + } + } + + if (stretch) { + /* + * We are going to include an optional io in our aggregated + * span, thus closing the write gap. Only mandatory i/os can + * start aggregated spans, so make sure that the next i/o + * after our span is mandatory. + */ + dio = AVL_NEXT(t, last); + ASSERT3P(dio, !=, NULL); + dio->io_flags &= ~ZIO_FLAG_OPTIONAL; + } else { + /* do not include the optional i/o */ + while (last != mandatory && last != first) { + ASSERT(last->io_flags & ZIO_FLAG_OPTIONAL); + last = AVL_PREV(t, last); + ASSERT(last != NULL); + } + } + + if (first == last) + return (NULL); + + size = IO_SPAN(first, last); + ASSERT3U(size, <=, SPA_MAXBLOCKSIZE); + + abd = abd_alloc_gang(); + if (abd == NULL) + return (NULL); + + aio = zio_vdev_delegated_io(first->io_vd, first->io_offset, + abd, size, first->io_type, zio->io_priority, + flags | ZIO_FLAG_DONT_QUEUE, vdev_queue_agg_io_done, NULL); + aio->io_timestamp = first->io_timestamp; + + nio = first; + next_offset = first->io_offset; + do { + dio = nio; + nio = AVL_NEXT(t, dio); + ASSERT3P(dio, !=, NULL); + zio_add_child(dio, aio); + vdev_queue_io_remove(vq, dio); + + if (dio->io_offset != next_offset) { + /* allocate a buffer for a read gap */ + ASSERT3U(dio->io_type, ==, ZIO_TYPE_READ); + ASSERT3U(dio->io_offset, >, next_offset); + abd = abd_alloc_for_io( + dio->io_offset - next_offset, B_TRUE); + abd_gang_add(aio->io_abd, abd, B_TRUE); + } + if (dio->io_abd && + (dio->io_size != abd_get_size(dio->io_abd))) { + /* abd size not the same as IO size */ + ASSERT3U(abd_get_size(dio->io_abd), >, dio->io_size); + abd = abd_get_offset_size(dio->io_abd, 0, dio->io_size); + abd_gang_add(aio->io_abd, abd, B_TRUE); + } else { + if (dio->io_flags & ZIO_FLAG_NODATA) { + /* allocate a buffer for a write gap */ + ASSERT3U(dio->io_type, ==, ZIO_TYPE_WRITE); + ASSERT0P(dio->io_abd); + abd_gang_add(aio->io_abd, + abd_get_zeros(dio->io_size), B_TRUE); + } else { + /* + * We pass B_FALSE to abd_gang_add() + * because we did not allocate a new + * ABD, so it is assumed the caller + * will free this ABD. + */ + abd_gang_add(aio->io_abd, dio->io_abd, + B_FALSE); + } + } + next_offset = dio->io_offset + dio->io_size; + } while (dio != last); + ASSERT3U(abd_get_size(aio->io_abd), ==, aio->io_size); + + /* + * Callers must call zio_vdev_io_bypass() and zio_execute() for + * aggregated (parent) I/Os so that we could avoid dropping the + * queue's lock here to avoid a deadlock that we could encounter + * due to lock order reversal between vq_lock and io_lock in + * zio_change_priority(). + */ + return (aio); +} + +static zio_t * +vdev_queue_io_to_issue(vdev_queue_t *vq) +{ + zio_t *zio, *aio; + zio_priority_t p; + avl_index_t idx; + avl_tree_t *tree; + +again: + ASSERT(MUTEX_HELD(&vq->vq_lock)); + + p = vdev_queue_class_to_issue(vq); + + if (p == ZIO_PRIORITY_NUM_QUEUEABLE) { + /* No eligible queued i/os */ + return (NULL); + } + + if (vdev_queue_class_fifo(p)) { + zio = list_head(&vq->vq_class[p].vqc_list); + } else { + /* + * For LBA-ordered queues (async / scrub / initializing), + * issue the I/O which follows the most recently issued I/O + * in LBA (offset) order, but to avoid starvation only within + * the same 0.5 second interval as the first I/O. + */ + tree = &vq->vq_class[p].vqc_tree; + zio = aio = avl_first(tree); + if (zio->io_offset < vq->vq_last_offset) { + vq->vq_io_search.io_timestamp = zio->io_timestamp; + vq->vq_io_search.io_offset = vq->vq_last_offset; + zio = avl_find(tree, &vq->vq_io_search, &idx); + if (zio == NULL) { + zio = avl_nearest(tree, idx, AVL_AFTER); + if (zio == NULL || + (zio->io_timestamp >> VDQ_T_SHIFT) != + (aio->io_timestamp >> VDQ_T_SHIFT)) + zio = aio; + } + } + } + ASSERT3U(zio->io_priority, ==, p); + + aio = vdev_queue_aggregate(vq, zio); + if (aio != NULL) { + zio = aio; + } else { + vdev_queue_io_remove(vq, zio); + + /* + * If the I/O is or was optional and therefore has no data, we + * need to simply discard it. We need to drop the vdev queue's + * lock to avoid a deadlock that we could encounter since this + * I/O will complete immediately. + */ + if (zio->io_flags & ZIO_FLAG_NODATA) { + mutex_exit(&vq->vq_lock); + zio_vdev_io_bypass(zio); + zio_execute(zio); + mutex_enter(&vq->vq_lock); + goto again; + } + } + + vdev_queue_pending_add(vq, zio); + vq->vq_last_offset = zio->io_offset + zio->io_size; + + return (zio); +} + +zio_t * +vdev_queue_io(zio_t *zio) +{ + vdev_queue_t *vq = &zio->io_vd->vdev_queue; + zio_t *dio, *nio; + zio_link_t *zl = NULL; + + if (zio->io_flags & ZIO_FLAG_DONT_QUEUE) + return (zio); + + /* + * Children i/os inherent their parent's priority, which might + * not match the child's i/o type. Fix it up here. + */ + if (zio->io_type == ZIO_TYPE_READ) { + ASSERT(zio->io_priority != ZIO_PRIORITY_TRIM); + + if (zio->io_priority != ZIO_PRIORITY_SYNC_READ && + zio->io_priority != ZIO_PRIORITY_ASYNC_READ && + zio->io_priority != ZIO_PRIORITY_SCRUB && + zio->io_priority != ZIO_PRIORITY_REMOVAL && + zio->io_priority != ZIO_PRIORITY_INITIALIZING && + zio->io_priority != ZIO_PRIORITY_REBUILD) { + zio->io_priority = ZIO_PRIORITY_ASYNC_READ; + } + } else if (zio->io_type == ZIO_TYPE_WRITE) { + ASSERT(zio->io_priority != ZIO_PRIORITY_TRIM); + + if (zio->io_priority != ZIO_PRIORITY_SYNC_WRITE && + zio->io_priority != ZIO_PRIORITY_ASYNC_WRITE && + zio->io_priority != ZIO_PRIORITY_REMOVAL && + zio->io_priority != ZIO_PRIORITY_INITIALIZING && + zio->io_priority != ZIO_PRIORITY_REBUILD) { + zio->io_priority = ZIO_PRIORITY_ASYNC_WRITE; + } + } else { + ASSERT(zio->io_type == ZIO_TYPE_TRIM); + ASSERT(zio->io_priority == ZIO_PRIORITY_TRIM); + } + + zio->io_flags |= ZIO_FLAG_DONT_QUEUE; + zio->io_timestamp = gethrtime(); + + mutex_enter(&vq->vq_lock); + vdev_queue_io_add(vq, zio); + nio = vdev_queue_io_to_issue(vq); + mutex_exit(&vq->vq_lock); + + if (nio == NULL) + return (NULL); + + if (nio->io_done == vdev_queue_agg_io_done) { + while ((dio = zio_walk_parents(nio, &zl)) != NULL) { + ASSERT3U(dio->io_type, ==, nio->io_type); + zio_vdev_io_bypass(dio); + zio_execute(dio); + } + zio_nowait(nio); + return (NULL); + } + + return (nio); +} + +void +vdev_queue_io_done(zio_t *zio) +{ + vdev_queue_t *vq = &zio->io_vd->vdev_queue; + zio_t *dio, *nio; + zio_link_t *zl = NULL; + + hrtime_t now = gethrtime(); + vq->vq_io_complete_ts = now; + vq->vq_io_delta_ts = zio->io_delta = now - zio->io_timestamp; + + mutex_enter(&vq->vq_lock); + vdev_queue_pending_remove(vq, zio); + + while ((nio = vdev_queue_io_to_issue(vq)) != NULL) { + mutex_exit(&vq->vq_lock); + if (nio->io_done == vdev_queue_agg_io_done) { + while ((dio = zio_walk_parents(nio, &zl)) != NULL) { + ASSERT3U(dio->io_type, ==, nio->io_type); + zio_vdev_io_bypass(dio); + zio_execute(dio); + } + zio_nowait(nio); + } else { + zio_vdev_io_reissue(nio); + zio_execute(nio); + } + mutex_enter(&vq->vq_lock); + } + + mutex_exit(&vq->vq_lock); +} + +void +vdev_queue_change_io_priority(zio_t *zio, zio_priority_t priority) +{ + vdev_queue_t *vq = &zio->io_vd->vdev_queue; + + /* + * ZIO_PRIORITY_NOW is used by the vdev cache code and the aggregate zio + * code to issue IOs without adding them to the vdev queue. In this + * case, the zio is already going to be issued as quickly as possible + * and so it doesn't need any reprioritization to help. + */ + if (zio->io_priority == ZIO_PRIORITY_NOW) + return; + + ASSERT3U(zio->io_priority, <, ZIO_PRIORITY_NUM_QUEUEABLE); + ASSERT3U(priority, <, ZIO_PRIORITY_NUM_QUEUEABLE); + + if (zio->io_type == ZIO_TYPE_READ) { + if (priority != ZIO_PRIORITY_SYNC_READ && + priority != ZIO_PRIORITY_ASYNC_READ && + priority != ZIO_PRIORITY_SCRUB) + priority = ZIO_PRIORITY_ASYNC_READ; + } else { + ASSERT(zio->io_type == ZIO_TYPE_WRITE); + if (priority != ZIO_PRIORITY_SYNC_WRITE && + priority != ZIO_PRIORITY_ASYNC_WRITE) + priority = ZIO_PRIORITY_ASYNC_WRITE; + } + + mutex_enter(&vq->vq_lock); + + /* + * If the zio is in none of the queues we can simply change + * the priority. If the zio is waiting to be submitted we must + * remove it from the queue and re-insert it with the new priority. + * Otherwise, the zio is currently active and we cannot change its + * priority. + */ + if (zio->io_queue_state == ZIO_QS_QUEUED) { + vdev_queue_class_remove(vq, zio); + zio->io_priority = priority; + vdev_queue_class_add(vq, zio); + } else if (zio->io_queue_state == ZIO_QS_NONE) { + zio->io_priority = priority; + } + + mutex_exit(&vq->vq_lock); +} + +boolean_t +vdev_queue_pool_busy(spa_t *spa) +{ + dsl_pool_t *dp = spa_get_dsl(spa); + uint64_t min_bytes = zfs_dirty_data_max * + zfs_vdev_async_write_active_min_dirty_percent / 100; + + return (dp->dp_dirty_total > min_bytes); +} + +/* + * As these two methods are only used for load calculations we're not + * concerned if we get an incorrect value on 32bit platforms due to lack of + * vq_lock mutex use here, instead we prefer to keep it lock free for + * performance. + */ +uint32_t +vdev_queue_length(vdev_t *vd) +{ + return (vd->vdev_queue.vq_active); +} + +uint64_t +vdev_queue_last_offset(vdev_t *vd) +{ + return (vd->vdev_queue.vq_last_offset); +} + +uint64_t +vdev_queue_class_length(vdev_t *vd, zio_priority_t p) +{ + vdev_queue_t *vq = &vd->vdev_queue; + if (vdev_queue_class_fifo(p)) + return (vq->vq_class[p].vqc_list_numnodes); + else + return (avl_numnodes(&vq->vq_class[p].vqc_tree)); +} + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, aggregation_limit, UINT, ZMOD_RW, + "Max vdev I/O aggregation size"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, aggregation_limit_non_rotating, UINT, + ZMOD_RW, "Max vdev I/O aggregation size for non-rotating media"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, read_gap_limit, UINT, ZMOD_RW, + "Aggregate read I/O over gap"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, write_gap_limit, UINT, ZMOD_RW, + "Aggregate write I/O over gap"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, max_active, UINT, ZMOD_RW, + "Maximum number of active I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_write_active_max_dirty_percent, + UINT, ZMOD_RW, "Async write concurrency max threshold"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_write_active_min_dirty_percent, + UINT, ZMOD_RW, "Async write concurrency min threshold"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_read_max_active, UINT, ZMOD_RW, + "Max active async read I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_read_min_active, UINT, ZMOD_RW, + "Min active async read I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_write_max_active, UINT, ZMOD_RW, + "Max active async write I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, async_write_min_active, UINT, ZMOD_RW, + "Min active async write I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, initializing_max_active, UINT, ZMOD_RW, + "Max active initializing I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, initializing_min_active, UINT, ZMOD_RW, + "Min active initializing I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, removal_max_active, UINT, ZMOD_RW, + "Max active removal I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, removal_min_active, UINT, ZMOD_RW, + "Min active removal I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, scrub_max_active, UINT, ZMOD_RW, + "Max active scrub I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, scrub_min_active, UINT, ZMOD_RW, + "Min active scrub I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, sync_read_max_active, UINT, ZMOD_RW, + "Max active sync read I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, sync_read_min_active, UINT, ZMOD_RW, + "Min active sync read I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, sync_write_max_active, UINT, ZMOD_RW, + "Max active sync write I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, sync_write_min_active, UINT, ZMOD_RW, + "Min active sync write I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, trim_max_active, UINT, ZMOD_RW, + "Max active trim/discard I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, trim_min_active, UINT, ZMOD_RW, + "Min active trim/discard I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, rebuild_max_active, UINT, ZMOD_RW, + "Max active rebuild I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, rebuild_min_active, UINT, ZMOD_RW, + "Min active rebuild I/Os per vdev"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, nia_credit, UINT, ZMOD_RW, + "Number of non-interactive I/Os to allow in sequence"); + +ZFS_MODULE_PARAM(zfs_vdev, zfs_vdev_, nia_delay, UINT, ZMOD_RW, + "Number of non-interactive I/Os before _max_active"); |