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 2008 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #include <sys/zfs_context.h> 27 #include <sys/spa.h> 28 #include <sys/vdev_impl.h> 29 #include <sys/zio.h> 30 #include <sys/avl.h> 31 32 /* 33 * These tunables are for performance analysis. 34 */ 35 /* 36 * zfs_vdev_max_pending is the maximum number of i/os concurrently 37 * pending to each device. zfs_vdev_min_pending is the initial number 38 * of i/os pending to each device (before it starts ramping up to 39 * max_pending). 40 */ 41 int zfs_vdev_max_pending = 35; 42 int zfs_vdev_min_pending = 4; 43 44 /* deadline = pri + (lbolt >> time_shift) */ 45 int zfs_vdev_time_shift = 6; 46 47 /* exponential I/O issue ramp-up rate */ 48 int zfs_vdev_ramp_rate = 2; 49 50 /* 51 * i/os will be aggregated into a single large i/o up to 52 * zfs_vdev_aggregation_limit bytes long. 53 */ 54 int zfs_vdev_aggregation_limit = SPA_MAXBLOCKSIZE; 55 56 /* 57 * Virtual device vector for disk I/O scheduling. 58 */ 59 int 60 vdev_queue_deadline_compare(const void *x1, const void *x2) 61 { 62 const zio_t *z1 = x1; 63 const zio_t *z2 = x2; 64 65 if (z1->io_deadline < z2->io_deadline) 66 return (-1); 67 if (z1->io_deadline > z2->io_deadline) 68 return (1); 69 70 if (z1->io_offset < z2->io_offset) 71 return (-1); 72 if (z1->io_offset > z2->io_offset) 73 return (1); 74 75 if (z1 < z2) 76 return (-1); 77 if (z1 > z2) 78 return (1); 79 80 return (0); 81 } 82 83 int 84 vdev_queue_offset_compare(const void *x1, const void *x2) 85 { 86 const zio_t *z1 = x1; 87 const zio_t *z2 = x2; 88 89 if (z1->io_offset < z2->io_offset) 90 return (-1); 91 if (z1->io_offset > z2->io_offset) 92 return (1); 93 94 if (z1 < z2) 95 return (-1); 96 if (z1 > z2) 97 return (1); 98 99 return (0); 100 } 101 102 void 103 vdev_queue_init(vdev_t *vd) 104 { 105 vdev_queue_t *vq = &vd->vdev_queue; 106 107 mutex_init(&vq->vq_lock, NULL, MUTEX_DEFAULT, NULL); 108 109 avl_create(&vq->vq_deadline_tree, vdev_queue_deadline_compare, 110 sizeof (zio_t), offsetof(struct zio, io_deadline_node)); 111 112 avl_create(&vq->vq_read_tree, vdev_queue_offset_compare, 113 sizeof (zio_t), offsetof(struct zio, io_offset_node)); 114 115 avl_create(&vq->vq_write_tree, vdev_queue_offset_compare, 116 sizeof (zio_t), offsetof(struct zio, io_offset_node)); 117 118 avl_create(&vq->vq_pending_tree, vdev_queue_offset_compare, 119 sizeof (zio_t), offsetof(struct zio, io_offset_node)); 120 } 121 122 void 123 vdev_queue_fini(vdev_t *vd) 124 { 125 vdev_queue_t *vq = &vd->vdev_queue; 126 127 avl_destroy(&vq->vq_deadline_tree); 128 avl_destroy(&vq->vq_read_tree); 129 avl_destroy(&vq->vq_write_tree); 130 avl_destroy(&vq->vq_pending_tree); 131 132 mutex_destroy(&vq->vq_lock); 133 } 134 135 static void 136 vdev_queue_io_add(vdev_queue_t *vq, zio_t *zio) 137 { 138 avl_add(&vq->vq_deadline_tree, zio); 139 avl_add(zio->io_vdev_tree, zio); 140 } 141 142 static void 143 vdev_queue_io_remove(vdev_queue_t *vq, zio_t *zio) 144 { 145 avl_remove(&vq->vq_deadline_tree, zio); 146 avl_remove(zio->io_vdev_tree, zio); 147 } 148 149 static void 150 vdev_queue_agg_io_done(zio_t *aio) 151 { 152 zio_t *dio; 153 uint64_t offset = 0; 154 155 while ((dio = aio->io_delegate_list) != NULL) { 156 if (aio->io_type == ZIO_TYPE_READ) 157 bcopy((char *)aio->io_data + offset, dio->io_data, 158 dio->io_size); 159 offset += dio->io_size; 160 aio->io_delegate_list = dio->io_delegate_next; 161 dio->io_delegate_next = NULL; 162 dio->io_error = aio->io_error; 163 zio_execute(dio); 164 } 165 ASSERT3U(offset, ==, aio->io_size); 166 167 zio_buf_free(aio->io_data, aio->io_size); 168 } 169 170 #define IS_ADJACENT(io, nio) \ 171 ((io)->io_offset + (io)->io_size == (nio)->io_offset) 172 173 static zio_t * 174 vdev_queue_io_to_issue(vdev_queue_t *vq, uint64_t pending_limit) 175 { 176 zio_t *fio, *lio, *aio, *dio; 177 avl_tree_t *tree; 178 uint64_t size; 179 int flags; 180 181 ASSERT(MUTEX_HELD(&vq->vq_lock)); 182 183 if (avl_numnodes(&vq->vq_pending_tree) >= pending_limit || 184 avl_numnodes(&vq->vq_deadline_tree) == 0) 185 return (NULL); 186 187 fio = lio = avl_first(&vq->vq_deadline_tree); 188 189 tree = fio->io_vdev_tree; 190 size = fio->io_size; 191 flags = fio->io_flags & ZIO_FLAG_AGG_INHERIT; 192 193 if (!(flags & ZIO_FLAG_DONT_AGGREGATE)) { 194 /* 195 * We can aggregate I/Os that are adjacent and of the 196 * same flavor, as expressed by the AGG_INHERIT flags. 197 * The latter is necessary so that certain attributes 198 * of the I/O, such as whether it's a normal I/O or a 199 * scrub/resilver, can be preserved in the aggregate. 200 */ 201 while ((dio = AVL_PREV(tree, fio)) != NULL && 202 IS_ADJACENT(dio, fio) && 203 (dio->io_flags & ZIO_FLAG_AGG_INHERIT) == flags && 204 size + dio->io_size <= zfs_vdev_aggregation_limit) { 205 dio->io_delegate_next = fio; 206 fio = dio; 207 size += dio->io_size; 208 } 209 while ((dio = AVL_NEXT(tree, lio)) != NULL && 210 IS_ADJACENT(lio, dio) && 211 (dio->io_flags & ZIO_FLAG_AGG_INHERIT) == flags && 212 size + dio->io_size <= zfs_vdev_aggregation_limit) { 213 lio->io_delegate_next = dio; 214 lio = dio; 215 size += dio->io_size; 216 } 217 } 218 219 if (fio != lio) { 220 char *buf = zio_buf_alloc(size); 221 uint64_t offset = 0; 222 223 ASSERT(size <= zfs_vdev_aggregation_limit); 224 225 aio = zio_vdev_delegated_io(fio->io_vd, fio->io_offset, 226 buf, size, fio->io_type, ZIO_PRIORITY_NOW, 227 flags | ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_QUEUE, 228 vdev_queue_agg_io_done, NULL); 229 230 aio->io_delegate_list = fio; 231 232 for (dio = fio; dio != NULL; dio = dio->io_delegate_next) { 233 ASSERT(dio->io_type == aio->io_type); 234 ASSERT(dio->io_vdev_tree == tree); 235 if (dio->io_type == ZIO_TYPE_WRITE) 236 bcopy(dio->io_data, buf + offset, dio->io_size); 237 offset += dio->io_size; 238 vdev_queue_io_remove(vq, dio); 239 zio_vdev_io_bypass(dio); 240 } 241 242 ASSERT(offset == size); 243 244 avl_add(&vq->vq_pending_tree, aio); 245 246 return (aio); 247 } 248 249 ASSERT(fio->io_vdev_tree == tree); 250 vdev_queue_io_remove(vq, fio); 251 252 avl_add(&vq->vq_pending_tree, fio); 253 254 return (fio); 255 } 256 257 zio_t * 258 vdev_queue_io(zio_t *zio) 259 { 260 vdev_queue_t *vq = &zio->io_vd->vdev_queue; 261 zio_t *nio; 262 263 ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE); 264 265 if (zio->io_flags & ZIO_FLAG_DONT_QUEUE) 266 return (zio); 267 268 zio->io_flags |= ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_QUEUE; 269 270 if (zio->io_type == ZIO_TYPE_READ) 271 zio->io_vdev_tree = &vq->vq_read_tree; 272 else 273 zio->io_vdev_tree = &vq->vq_write_tree; 274 275 mutex_enter(&vq->vq_lock); 276 277 zio->io_deadline = (lbolt64 >> zfs_vdev_time_shift) + zio->io_priority; 278 279 vdev_queue_io_add(vq, zio); 280 281 nio = vdev_queue_io_to_issue(vq, zfs_vdev_min_pending); 282 283 mutex_exit(&vq->vq_lock); 284 285 if (nio == NULL) 286 return (NULL); 287 288 if (nio->io_done == vdev_queue_agg_io_done) { 289 zio_nowait(nio); 290 return (NULL); 291 } 292 293 return (nio); 294 } 295 296 void 297 vdev_queue_io_done(zio_t *zio) 298 { 299 vdev_queue_t *vq = &zio->io_vd->vdev_queue; 300 301 mutex_enter(&vq->vq_lock); 302 303 avl_remove(&vq->vq_pending_tree, zio); 304 305 for (int i = 0; i < zfs_vdev_ramp_rate; i++) { 306 zio_t *nio = vdev_queue_io_to_issue(vq, zfs_vdev_max_pending); 307 if (nio == NULL) 308 break; 309 mutex_exit(&vq->vq_lock); 310 if (nio->io_done == vdev_queue_agg_io_done) { 311 zio_nowait(nio); 312 } else { 313 zio_vdev_io_reissue(nio); 314 zio_execute(nio); 315 } 316 mutex_enter(&vq->vq_lock); 317 } 318 319 mutex_exit(&vq->vq_lock); 320 } 321