Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/drivers/block/cfq-iosched.c |
| 3 | * |
| 4 | * CFQ, or complete fairness queueing, disk scheduler. |
| 5 | * |
| 6 | * Based on ideas from a previously unfinished io |
| 7 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. |
| 8 | * |
| 9 | * Copyright (C) 2003 Jens Axboe <axboe@suse.de> |
| 10 | */ |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/fs.h> |
| 13 | #include <linux/blkdev.h> |
| 14 | #include <linux/elevator.h> |
| 15 | #include <linux/bio.h> |
| 16 | #include <linux/config.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/slab.h> |
| 19 | #include <linux/init.h> |
| 20 | #include <linux/compiler.h> |
| 21 | #include <linux/hash.h> |
| 22 | #include <linux/rbtree.h> |
| 23 | #include <linux/mempool.h> |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 24 | #include <linux/ioprio.h> |
| 25 | #include <linux/writeback.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | |
| 27 | /* |
| 28 | * tunables |
| 29 | */ |
| 30 | static int cfq_quantum = 4; /* max queue in one round of service */ |
| 31 | static int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 32 | static int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | static int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ |
| 34 | static int cfq_back_penalty = 2; /* penalty of a backwards seek */ |
| 35 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 36 | static int cfq_slice_sync = HZ / 10; |
| 37 | static int cfq_slice_async = HZ / 50; |
| 38 | static int cfq_slice_async_rq = 2; |
| 39 | static int cfq_slice_idle = HZ / 50; |
| 40 | |
| 41 | #define CFQ_IDLE_GRACE (HZ / 10) |
| 42 | #define CFQ_SLICE_SCALE (5) |
| 43 | |
| 44 | #define CFQ_KEY_ASYNC (0) |
| 45 | |
| 46 | /* |
| 47 | * disable queueing at the driver/hardware level |
| 48 | */ |
| 49 | static int cfq_max_depth = 1; |
| 50 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | /* |
| 52 | * for the hash of cfqq inside the cfqd |
| 53 | */ |
| 54 | #define CFQ_QHASH_SHIFT 6 |
| 55 | #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) |
| 56 | #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) |
| 57 | |
| 58 | /* |
| 59 | * for the hash of crq inside the cfqq |
| 60 | */ |
| 61 | #define CFQ_MHASH_SHIFT 6 |
| 62 | #define CFQ_MHASH_BLOCK(sec) ((sec) >> 3) |
| 63 | #define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT) |
| 64 | #define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT) |
| 65 | #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) |
| 66 | #define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash) |
| 67 | |
| 68 | #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 69 | #define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | |
| 71 | #define RQ_DATA(rq) (rq)->elevator_private |
| 72 | |
| 73 | /* |
| 74 | * rb-tree defines |
| 75 | */ |
| 76 | #define RB_NONE (2) |
| 77 | #define RB_EMPTY(node) ((node)->rb_node == NULL) |
| 78 | #define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE |
| 79 | #define RB_CLEAR(node) do { \ |
| 80 | (node)->rb_parent = NULL; \ |
| 81 | RB_CLEAR_COLOR((node)); \ |
| 82 | (node)->rb_right = NULL; \ |
| 83 | (node)->rb_left = NULL; \ |
| 84 | } while (0) |
| 85 | #define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL) |
| 86 | #define ON_RB(node) ((node)->rb_color != RB_NONE) |
| 87 | #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) |
| 88 | #define rq_rb_key(rq) (rq)->sector |
| 89 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | static kmem_cache_t *crq_pool; |
| 91 | static kmem_cache_t *cfq_pool; |
| 92 | static kmem_cache_t *cfq_ioc_pool; |
| 93 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 94 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
| 95 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) |
| 96 | #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) |
| 97 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
| 98 | |
| 99 | #define cfq_cfqq_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) |
| 100 | |
| 101 | /* |
| 102 | * Per block device queue structure |
| 103 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | struct cfq_data { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 105 | atomic_t ref; |
| 106 | request_queue_t *queue; |
| 107 | |
| 108 | /* |
| 109 | * rr list of queues with requests and the count of them |
| 110 | */ |
| 111 | struct list_head rr_list[CFQ_PRIO_LISTS]; |
| 112 | struct list_head busy_rr; |
| 113 | struct list_head cur_rr; |
| 114 | struct list_head idle_rr; |
| 115 | unsigned int busy_queues; |
| 116 | |
| 117 | /* |
| 118 | * non-ordered list of empty cfqq's |
| 119 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | struct list_head empty_list; |
| 121 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 122 | /* |
| 123 | * cfqq lookup hash |
| 124 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | struct hlist_head *cfq_hash; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 127 | /* |
| 128 | * global crq hash for all queues |
| 129 | */ |
| 130 | struct hlist_head *crq_hash; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | |
| 132 | unsigned int max_queued; |
| 133 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | mempool_t *crq_pool; |
| 135 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 136 | int rq_in_driver; |
| 137 | |
| 138 | /* |
| 139 | * schedule slice state info |
| 140 | */ |
| 141 | /* |
| 142 | * idle window management |
| 143 | */ |
| 144 | struct timer_list idle_slice_timer; |
| 145 | struct work_struct unplug_work; |
| 146 | |
| 147 | struct cfq_queue *active_queue; |
| 148 | struct cfq_io_context *active_cic; |
| 149 | int cur_prio, cur_end_prio; |
| 150 | unsigned int dispatch_slice; |
| 151 | |
| 152 | struct timer_list idle_class_timer; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | |
| 154 | sector_t last_sector; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 155 | unsigned long last_end_request; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 157 | unsigned int rq_starved; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | |
| 159 | /* |
| 160 | * tunables, see top of file |
| 161 | */ |
| 162 | unsigned int cfq_quantum; |
| 163 | unsigned int cfq_queued; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 164 | unsigned int cfq_fifo_expire[2]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | unsigned int cfq_back_penalty; |
| 166 | unsigned int cfq_back_max; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 167 | unsigned int cfq_slice[2]; |
| 168 | unsigned int cfq_slice_async_rq; |
| 169 | unsigned int cfq_slice_idle; |
| 170 | unsigned int cfq_max_depth; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | }; |
| 172 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 173 | /* |
| 174 | * Per process-grouping structure |
| 175 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | struct cfq_queue { |
| 177 | /* reference count */ |
| 178 | atomic_t ref; |
| 179 | /* parent cfq_data */ |
| 180 | struct cfq_data *cfqd; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 181 | /* cfqq lookup hash */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | struct hlist_node cfq_hash; |
| 183 | /* hash key */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 184 | unsigned int key; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | /* on either rr or empty list of cfqd */ |
| 186 | struct list_head cfq_list; |
| 187 | /* sorted list of pending requests */ |
| 188 | struct rb_root sort_list; |
| 189 | /* if fifo isn't expired, next request to serve */ |
| 190 | struct cfq_rq *next_crq; |
| 191 | /* requests queued in sort_list */ |
| 192 | int queued[2]; |
| 193 | /* currently allocated requests */ |
| 194 | int allocated[2]; |
| 195 | /* fifo list of requests in sort_list */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 196 | struct list_head fifo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 198 | unsigned long slice_start; |
| 199 | unsigned long slice_end; |
| 200 | unsigned long slice_left; |
| 201 | unsigned long service_last; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | |
| 203 | /* number of requests that have been handed to the driver */ |
| 204 | int in_flight; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 205 | |
| 206 | /* io prio of this group */ |
| 207 | unsigned short ioprio, org_ioprio; |
| 208 | unsigned short ioprio_class, org_ioprio_class; |
| 209 | |
| 210 | /* whether queue is on rr (or empty) list */ |
| 211 | unsigned on_rr : 1; |
| 212 | /* idle slice, waiting for new request submission */ |
| 213 | unsigned wait_request : 1; |
| 214 | /* set when wait_request gets set, reset on first rq alloc */ |
| 215 | unsigned must_alloc : 1; |
| 216 | /* only gets one must_alloc per slice */ |
| 217 | unsigned must_alloc_slice : 1; |
| 218 | /* idle slice, request added, now waiting to dispatch it */ |
| 219 | unsigned must_dispatch : 1; |
| 220 | /* fifo expire per-slice */ |
| 221 | unsigned fifo_expire : 1; |
| 222 | |
| 223 | unsigned idle_window : 1; |
| 224 | unsigned prio_changed : 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | }; |
| 226 | |
| 227 | struct cfq_rq { |
| 228 | struct rb_node rb_node; |
| 229 | sector_t rb_key; |
| 230 | struct request *request; |
| 231 | struct hlist_node hash; |
| 232 | |
| 233 | struct cfq_queue *cfq_queue; |
| 234 | struct cfq_io_context *io_context; |
| 235 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 236 | unsigned in_flight : 1; |
| 237 | unsigned accounted : 1; |
| 238 | unsigned is_sync : 1; |
| 239 | unsigned requeued : 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | }; |
| 241 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 242 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | static void cfq_dispatch_sort(request_queue_t *, struct cfq_rq *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | static void cfq_put_cfqd(struct cfq_data *cfqd); |
| 245 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 246 | #define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 247 | |
| 248 | /* |
| 249 | * lots of deadline iosched dupes, can be abstracted later... |
| 250 | */ |
| 251 | static inline void cfq_del_crq_hash(struct cfq_rq *crq) |
| 252 | { |
| 253 | hlist_del_init(&crq->hash); |
| 254 | } |
| 255 | |
| 256 | static void cfq_remove_merge_hints(request_queue_t *q, struct cfq_rq *crq) |
| 257 | { |
| 258 | cfq_del_crq_hash(crq); |
| 259 | |
| 260 | if (q->last_merge == crq->request) |
| 261 | q->last_merge = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | } |
| 263 | |
| 264 | static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) |
| 265 | { |
| 266 | const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); |
| 267 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 268 | hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); |
| 269 | } |
| 270 | |
| 271 | static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) |
| 272 | { |
| 273 | struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)]; |
| 274 | struct hlist_node *entry, *next; |
| 275 | |
| 276 | hlist_for_each_safe(entry, next, hash_list) { |
| 277 | struct cfq_rq *crq = list_entry_hash(entry); |
| 278 | struct request *__rq = crq->request; |
| 279 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | if (!rq_mergeable(__rq)) { |
| 281 | cfq_del_crq_hash(crq); |
| 282 | continue; |
| 283 | } |
| 284 | |
| 285 | if (rq_hash_key(__rq) == offset) |
| 286 | return __rq; |
| 287 | } |
| 288 | |
| 289 | return NULL; |
| 290 | } |
| 291 | |
| 292 | /* |
| 293 | * Lifted from AS - choose which of crq1 and crq2 that is best served now. |
| 294 | * We choose the request that is closest to the head right now. Distance |
| 295 | * behind the head are penalized and only allowed to a certain extent. |
| 296 | */ |
| 297 | static struct cfq_rq * |
| 298 | cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) |
| 299 | { |
| 300 | sector_t last, s1, s2, d1 = 0, d2 = 0; |
| 301 | int r1_wrap = 0, r2_wrap = 0; /* requests are behind the disk head */ |
| 302 | unsigned long back_max; |
| 303 | |
| 304 | if (crq1 == NULL || crq1 == crq2) |
| 305 | return crq2; |
| 306 | if (crq2 == NULL) |
| 307 | return crq1; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 308 | if (crq1->requeued) |
| 309 | return crq1; |
| 310 | if (crq2->requeued) |
| 311 | return crq2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 312 | |
| 313 | s1 = crq1->request->sector; |
| 314 | s2 = crq2->request->sector; |
| 315 | |
| 316 | last = cfqd->last_sector; |
| 317 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | /* |
| 319 | * by definition, 1KiB is 2 sectors |
| 320 | */ |
| 321 | back_max = cfqd->cfq_back_max * 2; |
| 322 | |
| 323 | /* |
| 324 | * Strict one way elevator _except_ in the case where we allow |
| 325 | * short backward seeks which are biased as twice the cost of a |
| 326 | * similar forward seek. |
| 327 | */ |
| 328 | if (s1 >= last) |
| 329 | d1 = s1 - last; |
| 330 | else if (s1 + back_max >= last) |
| 331 | d1 = (last - s1) * cfqd->cfq_back_penalty; |
| 332 | else |
| 333 | r1_wrap = 1; |
| 334 | |
| 335 | if (s2 >= last) |
| 336 | d2 = s2 - last; |
| 337 | else if (s2 + back_max >= last) |
| 338 | d2 = (last - s2) * cfqd->cfq_back_penalty; |
| 339 | else |
| 340 | r2_wrap = 1; |
| 341 | |
| 342 | /* Found required data */ |
| 343 | if (!r1_wrap && r2_wrap) |
| 344 | return crq1; |
| 345 | else if (!r2_wrap && r1_wrap) |
| 346 | return crq2; |
| 347 | else if (r1_wrap && r2_wrap) { |
| 348 | /* both behind the head */ |
| 349 | if (s1 <= s2) |
| 350 | return crq1; |
| 351 | else |
| 352 | return crq2; |
| 353 | } |
| 354 | |
| 355 | /* Both requests in front of the head */ |
| 356 | if (d1 < d2) |
| 357 | return crq1; |
| 358 | else if (d2 < d1) |
| 359 | return crq2; |
| 360 | else { |
| 361 | if (s1 >= s2) |
| 362 | return crq1; |
| 363 | else |
| 364 | return crq2; |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | /* |
| 369 | * would be nice to take fifo expire time into account as well |
| 370 | */ |
| 371 | static struct cfq_rq * |
| 372 | cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 373 | struct cfq_rq *last) |
| 374 | { |
| 375 | struct cfq_rq *crq_next = NULL, *crq_prev = NULL; |
| 376 | struct rb_node *rbnext, *rbprev; |
| 377 | |
Jens Axboe | 3d25f35 | 2005-06-27 10:55:49 +0200 | [diff] [blame^] | 378 | rbnext = NULL; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 379 | if (ON_RB(&last->rb_node)) |
| 380 | rbnext = rb_next(&last->rb_node); |
Jens Axboe | 3d25f35 | 2005-06-27 10:55:49 +0200 | [diff] [blame^] | 381 | if (!rbnext) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 382 | rbnext = rb_first(&cfqq->sort_list); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 383 | if (rbnext == &last->rb_node) |
| 384 | rbnext = NULL; |
| 385 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | |
| 387 | rbprev = rb_prev(&last->rb_node); |
| 388 | |
| 389 | if (rbprev) |
| 390 | crq_prev = rb_entry_crq(rbprev); |
| 391 | if (rbnext) |
| 392 | crq_next = rb_entry_crq(rbnext); |
| 393 | |
| 394 | return cfq_choose_req(cfqd, crq_next, crq_prev); |
| 395 | } |
| 396 | |
| 397 | static void cfq_update_next_crq(struct cfq_rq *crq) |
| 398 | { |
| 399 | struct cfq_queue *cfqq = crq->cfq_queue; |
| 400 | |
| 401 | if (cfqq->next_crq == crq) |
| 402 | cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); |
| 403 | } |
| 404 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 405 | static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 407 | struct cfq_data *cfqd = cfqq->cfqd; |
| 408 | struct list_head *list, *entry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 409 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 410 | BUG_ON(!cfqq->on_rr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 411 | |
| 412 | list_del(&cfqq->cfq_list); |
| 413 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 414 | if (cfq_class_rt(cfqq)) |
| 415 | list = &cfqd->cur_rr; |
| 416 | else if (cfq_class_idle(cfqq)) |
| 417 | list = &cfqd->idle_rr; |
| 418 | else { |
| 419 | /* |
| 420 | * if cfqq has requests in flight, don't allow it to be |
| 421 | * found in cfq_set_active_queue before it has finished them. |
| 422 | * this is done to increase fairness between a process that |
| 423 | * has lots of io pending vs one that only generates one |
| 424 | * sporadically or synchronously |
| 425 | */ |
| 426 | if (cfqq->in_flight) |
| 427 | list = &cfqd->busy_rr; |
| 428 | else |
| 429 | list = &cfqd->rr_list[cfqq->ioprio]; |
| 430 | } |
| 431 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 432 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 433 | * if queue was preempted, just add to front to be fair. busy_rr |
| 434 | * isn't sorted. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 436 | if (preempted || list == &cfqd->busy_rr) { |
| 437 | list_add(&cfqq->cfq_list, list); |
| 438 | return; |
| 439 | } |
| 440 | |
| 441 | /* |
| 442 | * sort by when queue was last serviced |
| 443 | */ |
| 444 | entry = list; |
| 445 | while ((entry = entry->prev) != list) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | struct cfq_queue *__cfqq = list_entry_cfqq(entry); |
| 447 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 448 | if (!__cfqq->service_last) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | break; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 450 | if (time_before(__cfqq->service_last, cfqq->service_last)) |
| 451 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | } |
| 453 | |
| 454 | list_add(&cfqq->cfq_list, entry); |
| 455 | } |
| 456 | |
| 457 | /* |
| 458 | * add to busy list of queues for service, trying to be fair in ordering |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 459 | * the pending list according to last request service |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | */ |
| 461 | static inline void |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 462 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq, int requeue) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 464 | BUG_ON(cfqq->on_rr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | cfqq->on_rr = 1; |
| 466 | cfqd->busy_queues++; |
| 467 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 468 | cfq_resort_rr_list(cfqq, requeue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | } |
| 470 | |
| 471 | static inline void |
| 472 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 473 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 474 | BUG_ON(!cfqq->on_rr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | cfqq->on_rr = 0; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 476 | list_move(&cfqq->cfq_list, &cfqd->empty_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | |
| 478 | BUG_ON(!cfqd->busy_queues); |
| 479 | cfqd->busy_queues--; |
| 480 | } |
| 481 | |
| 482 | /* |
| 483 | * rb tree support functions |
| 484 | */ |
| 485 | static inline void cfq_del_crq_rb(struct cfq_rq *crq) |
| 486 | { |
| 487 | struct cfq_queue *cfqq = crq->cfq_queue; |
| 488 | |
| 489 | if (ON_RB(&crq->rb_node)) { |
| 490 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 491 | const int sync = crq->is_sync; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 493 | BUG_ON(!cfqq->queued[sync]); |
| 494 | cfqq->queued[sync]--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 495 | |
| 496 | cfq_update_next_crq(crq); |
| 497 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 498 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
| 499 | RB_CLEAR_COLOR(&crq->rb_node); |
| 500 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 501 | if (cfqq->on_rr && RB_EMPTY(&cfqq->sort_list)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | cfq_del_cfqq_rr(cfqd, cfqq); |
| 503 | } |
| 504 | } |
| 505 | |
| 506 | static struct cfq_rq * |
| 507 | __cfq_add_crq_rb(struct cfq_rq *crq) |
| 508 | { |
| 509 | struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; |
| 510 | struct rb_node *parent = NULL; |
| 511 | struct cfq_rq *__crq; |
| 512 | |
| 513 | while (*p) { |
| 514 | parent = *p; |
| 515 | __crq = rb_entry_crq(parent); |
| 516 | |
| 517 | if (crq->rb_key < __crq->rb_key) |
| 518 | p = &(*p)->rb_left; |
| 519 | else if (crq->rb_key > __crq->rb_key) |
| 520 | p = &(*p)->rb_right; |
| 521 | else |
| 522 | return __crq; |
| 523 | } |
| 524 | |
| 525 | rb_link_node(&crq->rb_node, parent, p); |
| 526 | return NULL; |
| 527 | } |
| 528 | |
| 529 | static void cfq_add_crq_rb(struct cfq_rq *crq) |
| 530 | { |
| 531 | struct cfq_queue *cfqq = crq->cfq_queue; |
| 532 | struct cfq_data *cfqd = cfqq->cfqd; |
| 533 | struct request *rq = crq->request; |
| 534 | struct cfq_rq *__alias; |
| 535 | |
| 536 | crq->rb_key = rq_rb_key(rq); |
| 537 | cfqq->queued[crq->is_sync]++; |
| 538 | |
| 539 | /* |
| 540 | * looks a little odd, but the first insert might return an alias. |
| 541 | * if that happens, put the alias on the dispatch list |
| 542 | */ |
| 543 | while ((__alias = __cfq_add_crq_rb(crq)) != NULL) |
| 544 | cfq_dispatch_sort(cfqd->queue, __alias); |
| 545 | |
| 546 | rb_insert_color(&crq->rb_node, &cfqq->sort_list); |
| 547 | |
| 548 | if (!cfqq->on_rr) |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 549 | cfq_add_cfqq_rr(cfqd, cfqq, crq->requeued); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | |
| 551 | /* |
| 552 | * check if this request is a better next-serve candidate |
| 553 | */ |
| 554 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); |
| 555 | } |
| 556 | |
| 557 | static inline void |
| 558 | cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) |
| 559 | { |
| 560 | if (ON_RB(&crq->rb_node)) { |
| 561 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
| 562 | cfqq->queued[crq->is_sync]--; |
| 563 | } |
| 564 | |
| 565 | cfq_add_crq_rb(crq); |
| 566 | } |
| 567 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 568 | static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) |
| 569 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 570 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 571 | struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 572 | struct rb_node *n; |
| 573 | |
| 574 | if (!cfqq) |
| 575 | goto out; |
| 576 | |
| 577 | n = cfqq->sort_list.rb_node; |
| 578 | while (n) { |
| 579 | struct cfq_rq *crq = rb_entry_crq(n); |
| 580 | |
| 581 | if (sector < crq->rb_key) |
| 582 | n = n->rb_left; |
| 583 | else if (sector > crq->rb_key) |
| 584 | n = n->rb_right; |
| 585 | else |
| 586 | return crq->request; |
| 587 | } |
| 588 | |
| 589 | out: |
| 590 | return NULL; |
| 591 | } |
| 592 | |
| 593 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) |
| 594 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 595 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 596 | struct cfq_rq *crq = RQ_DATA(rq); |
| 597 | |
| 598 | if (crq) { |
| 599 | struct cfq_queue *cfqq = crq->cfq_queue; |
| 600 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 601 | if (crq->accounted) { |
| 602 | crq->accounted = 0; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 603 | WARN_ON(!cfqd->rq_in_driver); |
| 604 | cfqd->rq_in_driver--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 606 | if (crq->in_flight) { |
| 607 | crq->in_flight = 0; |
| 608 | WARN_ON(!cfqq->in_flight); |
| 609 | cfqq->in_flight--; |
| 610 | } |
| 611 | crq->requeued = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | } |
| 613 | } |
| 614 | |
| 615 | /* |
| 616 | * make sure the service time gets corrected on reissue of this request |
| 617 | */ |
| 618 | static void cfq_requeue_request(request_queue_t *q, struct request *rq) |
| 619 | { |
| 620 | cfq_deactivate_request(q, rq); |
| 621 | list_add(&rq->queuelist, &q->queue_head); |
| 622 | } |
| 623 | |
| 624 | static void cfq_remove_request(request_queue_t *q, struct request *rq) |
| 625 | { |
| 626 | struct cfq_rq *crq = RQ_DATA(rq); |
| 627 | |
| 628 | if (crq) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 629 | list_del_init(&rq->queuelist); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 630 | cfq_del_crq_rb(crq); |
| 631 | cfq_remove_merge_hints(q, crq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 633 | } |
| 634 | } |
| 635 | |
| 636 | static int |
| 637 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) |
| 638 | { |
| 639 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 640 | struct request *__rq; |
| 641 | int ret; |
| 642 | |
| 643 | ret = elv_try_last_merge(q, bio); |
| 644 | if (ret != ELEVATOR_NO_MERGE) { |
| 645 | __rq = q->last_merge; |
| 646 | goto out_insert; |
| 647 | } |
| 648 | |
| 649 | __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 650 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
| 651 | ret = ELEVATOR_BACK_MERGE; |
| 652 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | } |
| 654 | |
| 655 | __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 656 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
| 657 | ret = ELEVATOR_FRONT_MERGE; |
| 658 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | } |
| 660 | |
| 661 | return ELEVATOR_NO_MERGE; |
| 662 | out: |
| 663 | q->last_merge = __rq; |
| 664 | out_insert: |
| 665 | *req = __rq; |
| 666 | return ret; |
| 667 | } |
| 668 | |
| 669 | static void cfq_merged_request(request_queue_t *q, struct request *req) |
| 670 | { |
| 671 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 672 | struct cfq_rq *crq = RQ_DATA(req); |
| 673 | |
| 674 | cfq_del_crq_hash(crq); |
| 675 | cfq_add_crq_hash(cfqd, crq); |
| 676 | |
| 677 | if (ON_RB(&crq->rb_node) && (rq_rb_key(req) != crq->rb_key)) { |
| 678 | struct cfq_queue *cfqq = crq->cfq_queue; |
| 679 | |
| 680 | cfq_update_next_crq(crq); |
| 681 | cfq_reposition_crq_rb(cfqq, crq); |
| 682 | } |
| 683 | |
| 684 | q->last_merge = req; |
| 685 | } |
| 686 | |
| 687 | static void |
| 688 | cfq_merged_requests(request_queue_t *q, struct request *rq, |
| 689 | struct request *next) |
| 690 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 691 | cfq_merged_request(q, rq); |
| 692 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 693 | /* |
| 694 | * reposition in fifo if next is older than rq |
| 695 | */ |
| 696 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && |
| 697 | time_before(next->start_time, rq->start_time)) |
| 698 | list_move(&rq->queuelist, &next->queuelist); |
| 699 | |
| 700 | cfq_remove_request(q, next); |
| 701 | } |
| 702 | |
| 703 | static inline void |
| 704 | __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 705 | { |
| 706 | if (cfqq) { |
| 707 | /* |
| 708 | * stop potential idle class queues waiting service |
| 709 | */ |
| 710 | del_timer(&cfqd->idle_class_timer); |
| 711 | |
| 712 | cfqq->slice_start = jiffies; |
| 713 | cfqq->slice_end = 0; |
| 714 | cfqq->slice_left = 0; |
| 715 | cfqq->must_alloc_slice = 0; |
| 716 | cfqq->fifo_expire = 0; |
| 717 | } |
| 718 | |
| 719 | cfqd->active_queue = cfqq; |
| 720 | } |
| 721 | |
| 722 | /* |
| 723 | * 0 |
| 724 | * 0,1 |
| 725 | * 0,1,2 |
| 726 | * 0,1,2,3 |
| 727 | * 0,1,2,3,4 |
| 728 | * 0,1,2,3,4,5 |
| 729 | * 0,1,2,3,4,5,6 |
| 730 | * 0,1,2,3,4,5,6,7 |
| 731 | */ |
| 732 | static int cfq_get_next_prio_level(struct cfq_data *cfqd) |
| 733 | { |
| 734 | int prio, wrap; |
| 735 | |
| 736 | prio = -1; |
| 737 | wrap = 0; |
| 738 | do { |
| 739 | int p; |
| 740 | |
| 741 | for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { |
| 742 | if (!list_empty(&cfqd->rr_list[p])) { |
| 743 | prio = p; |
| 744 | break; |
| 745 | } |
| 746 | } |
| 747 | |
| 748 | if (prio != -1) |
| 749 | break; |
| 750 | cfqd->cur_prio = 0; |
| 751 | if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { |
| 752 | cfqd->cur_end_prio = 0; |
| 753 | if (wrap) |
| 754 | break; |
| 755 | wrap = 1; |
| 756 | } |
| 757 | } while (1); |
| 758 | |
| 759 | if (unlikely(prio == -1)) |
| 760 | return -1; |
| 761 | |
| 762 | BUG_ON(prio >= CFQ_PRIO_LISTS); |
| 763 | |
| 764 | list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); |
| 765 | |
| 766 | cfqd->cur_prio = prio + 1; |
| 767 | if (cfqd->cur_prio > cfqd->cur_end_prio) { |
| 768 | cfqd->cur_end_prio = cfqd->cur_prio; |
| 769 | cfqd->cur_prio = 0; |
| 770 | } |
| 771 | if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { |
| 772 | cfqd->cur_prio = 0; |
| 773 | cfqd->cur_end_prio = 0; |
| 774 | } |
| 775 | |
| 776 | return prio; |
| 777 | } |
| 778 | |
| 779 | static void cfq_set_active_queue(struct cfq_data *cfqd) |
| 780 | { |
| 781 | struct cfq_queue *cfqq = NULL; |
| 782 | |
| 783 | /* |
| 784 | * if current list is non-empty, grab first entry. if it is empty, |
| 785 | * get next prio level and grab first entry then if any are spliced |
| 786 | */ |
| 787 | if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) |
| 788 | cfqq = list_entry_cfqq(cfqd->cur_rr.next); |
| 789 | |
| 790 | /* |
| 791 | * if we have idle queues and no rt or be queues had pending |
| 792 | * requests, either allow immediate service if the grace period |
| 793 | * has passed or arm the idle grace timer |
| 794 | */ |
| 795 | if (!cfqq && !list_empty(&cfqd->idle_rr)) { |
| 796 | unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; |
| 797 | |
| 798 | if (time_after_eq(jiffies, end)) |
| 799 | cfqq = list_entry_cfqq(cfqd->idle_rr.next); |
| 800 | else |
| 801 | mod_timer(&cfqd->idle_class_timer, end); |
| 802 | } |
| 803 | |
| 804 | __cfq_set_active_queue(cfqd, cfqq); |
| 805 | } |
| 806 | |
| 807 | /* |
| 808 | * current cfqq expired its slice (or was too idle), select new one |
| 809 | */ |
| 810 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) |
| 811 | { |
| 812 | struct cfq_queue *cfqq = cfqd->active_queue; |
| 813 | |
| 814 | if (cfqq) { |
| 815 | unsigned long now = jiffies; |
| 816 | |
| 817 | if (cfqq->wait_request) |
| 818 | del_timer(&cfqd->idle_slice_timer); |
| 819 | |
| 820 | if (!preempted && !cfqq->in_flight) |
| 821 | cfqq->service_last = now; |
| 822 | |
| 823 | cfqq->must_dispatch = 0; |
| 824 | cfqq->wait_request = 0; |
| 825 | |
| 826 | /* |
| 827 | * store what was left of this slice, if the queue idled out |
| 828 | * or was preempted |
| 829 | */ |
| 830 | if (time_after(now, cfqq->slice_end)) |
| 831 | cfqq->slice_left = now - cfqq->slice_end; |
| 832 | else |
| 833 | cfqq->slice_left = 0; |
| 834 | |
| 835 | if (cfqq->on_rr) |
| 836 | cfq_resort_rr_list(cfqq, preempted); |
| 837 | |
| 838 | cfqd->active_queue = NULL; |
| 839 | |
| 840 | if (cfqd->active_cic) { |
| 841 | put_io_context(cfqd->active_cic->ioc); |
| 842 | cfqd->active_cic = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 843 | } |
| 844 | } |
| 845 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 846 | cfqd->dispatch_slice = 0; |
| 847 | } |
| 848 | |
| 849 | static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 850 | |
| 851 | { |
| 852 | WARN_ON(!RB_EMPTY(&cfqq->sort_list)); |
| 853 | WARN_ON(cfqq != cfqd->active_queue); |
| 854 | |
| 855 | /* |
| 856 | * idle is disabled, either manually or by past process history |
| 857 | */ |
| 858 | if (!cfqd->cfq_slice_idle) |
| 859 | return 0; |
| 860 | if (!cfqq->idle_window) |
| 861 | return 0; |
| 862 | /* |
| 863 | * task has exited, don't wait |
| 864 | */ |
| 865 | if (cfqd->active_cic && !cfqd->active_cic->ioc->task) |
| 866 | return 0; |
| 867 | |
| 868 | cfqq->wait_request = 1; |
| 869 | cfqq->must_alloc = 1; |
| 870 | |
| 871 | if (!timer_pending(&cfqd->idle_slice_timer)) { |
| 872 | unsigned long slice_left = cfqq->slice_end - 1; |
| 873 | |
| 874 | cfqd->idle_slice_timer.expires = min(jiffies + cfqd->cfq_slice_idle, slice_left); |
| 875 | add_timer(&cfqd->idle_slice_timer); |
| 876 | } |
| 877 | |
| 878 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 879 | } |
| 880 | |
| 881 | /* |
| 882 | * we dispatch cfqd->cfq_quantum requests in total from the rr_list queues, |
| 883 | * this function sector sorts the selected request to minimize seeks. we start |
| 884 | * at cfqd->last_sector, not 0. |
| 885 | */ |
| 886 | static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq) |
| 887 | { |
| 888 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 889 | struct cfq_queue *cfqq = crq->cfq_queue; |
| 890 | struct list_head *head = &q->queue_head, *entry = head; |
| 891 | struct request *__rq; |
| 892 | sector_t last; |
| 893 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 894 | list_del(&crq->request->queuelist); |
| 895 | |
| 896 | last = cfqd->last_sector; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 897 | list_for_each_entry_reverse(__rq, head, queuelist) { |
| 898 | struct cfq_rq *__crq = RQ_DATA(__rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 899 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 900 | if (blk_barrier_rq(__rq)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 901 | break; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 902 | if (!blk_fs_request(__rq)) |
| 903 | break; |
| 904 | if (__crq->requeued) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 905 | break; |
| 906 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 907 | if (__rq->sector <= crq->request->sector) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 908 | break; |
| 909 | if (__rq->sector > last && crq->request->sector < last) { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 910 | last = crq->request->sector + crq->request->nr_sectors; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 911 | break; |
| 912 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 913 | entry = &__rq->queuelist; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 914 | } |
| 915 | |
| 916 | cfqd->last_sector = last; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 917 | |
| 918 | cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); |
| 919 | |
| 920 | cfq_del_crq_rb(crq); |
| 921 | cfq_remove_merge_hints(q, crq); |
| 922 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 923 | crq->in_flight = 1; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 924 | crq->requeued = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 925 | cfqq->in_flight++; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 926 | list_add_tail(&crq->request->queuelist, entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 927 | } |
| 928 | |
| 929 | /* |
| 930 | * return expired entry, or NULL to just start from scratch in rbtree |
| 931 | */ |
| 932 | static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) |
| 933 | { |
| 934 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 935 | struct request *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 936 | struct cfq_rq *crq; |
| 937 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 938 | if (cfqq->fifo_expire) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 939 | return NULL; |
| 940 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 941 | if (!list_empty(&cfqq->fifo)) { |
| 942 | int fifo = cfq_cfqq_sync(cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 943 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 944 | crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); |
| 945 | rq = crq->request; |
| 946 | if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { |
| 947 | cfqq->fifo_expire = 1; |
| 948 | return crq; |
| 949 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 950 | } |
| 951 | |
| 952 | return NULL; |
| 953 | } |
| 954 | |
| 955 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 956 | * Scale schedule slice based on io priority |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 957 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 958 | static inline int |
| 959 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 960 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 961 | const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 962 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 963 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 964 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 965 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 966 | } |
| 967 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 968 | static inline void |
| 969 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 970 | { |
| 971 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
| 972 | } |
| 973 | |
| 974 | static inline int |
| 975 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 976 | { |
| 977 | const int base_rq = cfqd->cfq_slice_async_rq; |
| 978 | |
| 979 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
| 980 | |
| 981 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
| 982 | } |
| 983 | |
| 984 | /* |
| 985 | * get next queue for service |
| 986 | */ |
| 987 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force) |
| 988 | { |
| 989 | unsigned long now = jiffies; |
| 990 | struct cfq_queue *cfqq; |
| 991 | |
| 992 | cfqq = cfqd->active_queue; |
| 993 | if (!cfqq) |
| 994 | goto new_queue; |
| 995 | |
| 996 | /* |
| 997 | * slice has expired |
| 998 | */ |
| 999 | if (!cfqq->must_dispatch && time_after(jiffies, cfqq->slice_end)) |
| 1000 | goto new_queue; |
| 1001 | |
| 1002 | /* |
| 1003 | * if queue has requests, dispatch one. if not, check if |
| 1004 | * enough slice is left to wait for one |
| 1005 | */ |
| 1006 | if (!RB_EMPTY(&cfqq->sort_list)) |
| 1007 | goto keep_queue; |
| 1008 | else if (!force && cfq_cfqq_sync(cfqq) && |
| 1009 | time_before(now, cfqq->slice_end)) { |
| 1010 | if (cfq_arm_slice_timer(cfqd, cfqq)) |
| 1011 | return NULL; |
| 1012 | } |
| 1013 | |
| 1014 | new_queue: |
| 1015 | cfq_slice_expired(cfqd, 0); |
| 1016 | cfq_set_active_queue(cfqd); |
| 1017 | keep_queue: |
| 1018 | return cfqd->active_queue; |
| 1019 | } |
| 1020 | |
| 1021 | static int |
| 1022 | __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 1023 | int max_dispatch) |
| 1024 | { |
| 1025 | int dispatched = 0; |
| 1026 | |
| 1027 | BUG_ON(RB_EMPTY(&cfqq->sort_list)); |
| 1028 | |
| 1029 | do { |
| 1030 | struct cfq_rq *crq; |
| 1031 | |
| 1032 | /* |
| 1033 | * follow expired path, else get first next available |
| 1034 | */ |
| 1035 | if ((crq = cfq_check_fifo(cfqq)) == NULL) |
| 1036 | crq = cfqq->next_crq; |
| 1037 | |
| 1038 | /* |
| 1039 | * finally, insert request into driver dispatch list |
| 1040 | */ |
| 1041 | cfq_dispatch_sort(cfqd->queue, crq); |
| 1042 | |
| 1043 | cfqd->dispatch_slice++; |
| 1044 | dispatched++; |
| 1045 | |
| 1046 | if (!cfqd->active_cic) { |
| 1047 | atomic_inc(&crq->io_context->ioc->refcount); |
| 1048 | cfqd->active_cic = crq->io_context; |
| 1049 | } |
| 1050 | |
| 1051 | if (RB_EMPTY(&cfqq->sort_list)) |
| 1052 | break; |
| 1053 | |
| 1054 | } while (dispatched < max_dispatch); |
| 1055 | |
| 1056 | /* |
| 1057 | * if slice end isn't set yet, set it. if at least one request was |
| 1058 | * sync, use the sync time slice value |
| 1059 | */ |
| 1060 | if (!cfqq->slice_end) |
| 1061 | cfq_set_prio_slice(cfqd, cfqq); |
| 1062 | |
| 1063 | /* |
| 1064 | * expire an async queue immediately if it has used up its slice. idle |
| 1065 | * queue always expire after 1 dispatch round. |
| 1066 | */ |
| 1067 | if ((!cfq_cfqq_sync(cfqq) && |
| 1068 | cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || |
| 1069 | cfq_class_idle(cfqq)) |
| 1070 | cfq_slice_expired(cfqd, 0); |
| 1071 | |
| 1072 | return dispatched; |
| 1073 | } |
| 1074 | |
| 1075 | static int |
| 1076 | cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1077 | { |
| 1078 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 1079 | struct cfq_queue *cfqq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1080 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1081 | if (!cfqd->busy_queues) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1082 | return 0; |
| 1083 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1084 | cfqq = cfq_select_queue(cfqd, force); |
| 1085 | if (cfqq) { |
| 1086 | cfqq->wait_request = 0; |
| 1087 | cfqq->must_dispatch = 0; |
| 1088 | del_timer(&cfqd->idle_slice_timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1089 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1090 | if (cfq_class_idle(cfqq)) |
| 1091 | max_dispatch = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1092 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1093 | return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1094 | } |
| 1095 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1096 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | } |
| 1098 | |
| 1099 | static inline void cfq_account_dispatch(struct cfq_rq *crq) |
| 1100 | { |
| 1101 | struct cfq_queue *cfqq = crq->cfq_queue; |
| 1102 | struct cfq_data *cfqd = cfqq->cfqd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1103 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1104 | if (unlikely(!blk_fs_request(crq->request))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1105 | return; |
| 1106 | |
| 1107 | /* |
| 1108 | * accounted bit is necessary since some drivers will call |
| 1109 | * elv_next_request() many times for the same request (eg ide) |
| 1110 | */ |
| 1111 | if (crq->accounted) |
| 1112 | return; |
| 1113 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1114 | crq->accounted = 1; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1115 | cfqd->rq_in_driver++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1116 | } |
| 1117 | |
| 1118 | static inline void |
| 1119 | cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq) |
| 1120 | { |
| 1121 | struct cfq_data *cfqd = cfqq->cfqd; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1122 | unsigned long now; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1123 | |
| 1124 | if (!crq->accounted) |
| 1125 | return; |
| 1126 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1127 | now = jiffies; |
| 1128 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1129 | WARN_ON(!cfqd->rq_in_driver); |
| 1130 | cfqd->rq_in_driver--; |
| 1131 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1132 | if (!cfq_class_idle(cfqq)) |
| 1133 | cfqd->last_end_request = now; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1134 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1135 | if (!cfqq->in_flight && cfqq->on_rr) { |
| 1136 | cfqq->service_last = now; |
| 1137 | cfq_resort_rr_list(cfqq, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1138 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1139 | |
| 1140 | if (crq->is_sync) |
| 1141 | crq->io_context->last_end_request = now; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1142 | } |
| 1143 | |
| 1144 | static struct request *cfq_next_request(request_queue_t *q) |
| 1145 | { |
| 1146 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 1147 | struct request *rq; |
| 1148 | |
| 1149 | if (!list_empty(&q->queue_head)) { |
| 1150 | struct cfq_rq *crq; |
| 1151 | dispatch: |
| 1152 | rq = list_entry_rq(q->queue_head.next); |
| 1153 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1154 | crq = RQ_DATA(rq); |
| 1155 | if (crq) { |
| 1156 | /* |
| 1157 | * if idle window is disabled, allow queue buildup |
| 1158 | */ |
| 1159 | if (!crq->in_flight && !crq->cfq_queue->idle_window && |
| 1160 | cfqd->rq_in_driver >= cfqd->cfq_max_depth) |
| 1161 | return NULL; |
| 1162 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1163 | cfq_remove_merge_hints(q, crq); |
| 1164 | cfq_account_dispatch(crq); |
| 1165 | } |
| 1166 | |
| 1167 | return rq; |
| 1168 | } |
| 1169 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1170 | if (cfq_dispatch_requests(q, cfqd->cfq_quantum, 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1171 | goto dispatch; |
| 1172 | |
| 1173 | return NULL; |
| 1174 | } |
| 1175 | |
| 1176 | /* |
| 1177 | * task holds one reference to the queue, dropped when task exits. each crq |
| 1178 | * in-flight on this queue also holds a reference, dropped when crq is freed. |
| 1179 | * |
| 1180 | * queue lock must be held here. |
| 1181 | */ |
| 1182 | static void cfq_put_queue(struct cfq_queue *cfqq) |
| 1183 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1184 | struct cfq_data *cfqd = cfqq->cfqd; |
| 1185 | |
| 1186 | BUG_ON(atomic_read(&cfqq->ref) <= 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1187 | |
| 1188 | if (!atomic_dec_and_test(&cfqq->ref)) |
| 1189 | return; |
| 1190 | |
| 1191 | BUG_ON(rb_first(&cfqq->sort_list)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1192 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1193 | BUG_ON(cfqq->on_rr); |
| 1194 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1195 | if (unlikely(cfqd->active_queue == cfqq)) { |
| 1196 | cfq_slice_expired(cfqd, 0); |
| 1197 | kblockd_schedule_work(&cfqd->unplug_work); |
| 1198 | } |
| 1199 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1200 | cfq_put_cfqd(cfqq->cfqd); |
| 1201 | |
| 1202 | /* |
| 1203 | * it's on the empty list and still hashed |
| 1204 | */ |
| 1205 | list_del(&cfqq->cfq_list); |
| 1206 | hlist_del(&cfqq->cfq_hash); |
| 1207 | kmem_cache_free(cfq_pool, cfqq); |
| 1208 | } |
| 1209 | |
| 1210 | static inline struct cfq_queue * |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1211 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, const int hashval) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1212 | { |
| 1213 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; |
| 1214 | struct hlist_node *entry, *next; |
| 1215 | |
| 1216 | hlist_for_each_safe(entry, next, hash_list) { |
| 1217 | struct cfq_queue *__cfqq = list_entry_qhash(entry); |
| 1218 | |
| 1219 | if (__cfqq->key == key) |
| 1220 | return __cfqq; |
| 1221 | } |
| 1222 | |
| 1223 | return NULL; |
| 1224 | } |
| 1225 | |
| 1226 | static struct cfq_queue * |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1227 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1228 | { |
| 1229 | return __cfq_find_cfq_hash(cfqd, key, hash_long(key, CFQ_QHASH_SHIFT)); |
| 1230 | } |
| 1231 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1232 | static void cfq_free_io_context(struct cfq_io_context *cic) |
| 1233 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1234 | struct cfq_io_context *__cic; |
| 1235 | struct list_head *entry, *next; |
| 1236 | |
| 1237 | list_for_each_safe(entry, next, &cic->list) { |
| 1238 | __cic = list_entry(entry, struct cfq_io_context, list); |
| 1239 | kmem_cache_free(cfq_ioc_pool, __cic); |
| 1240 | } |
| 1241 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1242 | kmem_cache_free(cfq_ioc_pool, cic); |
| 1243 | } |
| 1244 | |
| 1245 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1246 | * Called with interrupts disabled |
| 1247 | */ |
| 1248 | static void cfq_exit_single_io_context(struct cfq_io_context *cic) |
| 1249 | { |
| 1250 | struct cfq_data *cfqd = cic->cfqq->cfqd; |
| 1251 | request_queue_t *q = cfqd->queue; |
| 1252 | |
| 1253 | WARN_ON(!irqs_disabled()); |
| 1254 | |
| 1255 | spin_lock(q->queue_lock); |
| 1256 | |
| 1257 | if (unlikely(cic->cfqq == cfqd->active_queue)) { |
| 1258 | cfq_slice_expired(cfqd, 0); |
| 1259 | kblockd_schedule_work(&cfqd->unplug_work); |
| 1260 | } |
| 1261 | |
| 1262 | cfq_put_queue(cic->cfqq); |
| 1263 | cic->cfqq = NULL; |
| 1264 | spin_unlock(q->queue_lock); |
| 1265 | } |
| 1266 | |
| 1267 | /* |
| 1268 | * Another task may update the task cic list, if it is doing a queue lookup |
| 1269 | * on its behalf. cfq_cic_lock excludes such concurrent updates |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1270 | */ |
| 1271 | static void cfq_exit_io_context(struct cfq_io_context *cic) |
| 1272 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1273 | struct cfq_io_context *__cic; |
| 1274 | struct list_head *entry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1275 | unsigned long flags; |
| 1276 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1277 | local_irq_save(flags); |
| 1278 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1279 | /* |
| 1280 | * put the reference this task is holding to the various queues |
| 1281 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1282 | list_for_each(entry, &cic->list) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1283 | __cic = list_entry(entry, struct cfq_io_context, list); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1284 | cfq_exit_single_io_context(__cic); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1285 | } |
| 1286 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1287 | cfq_exit_single_io_context(cic); |
| 1288 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1289 | } |
| 1290 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1291 | static struct cfq_io_context * |
| 1292 | cfq_alloc_io_context(struct cfq_data *cfqd, int gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1293 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1294 | struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1295 | |
| 1296 | if (cic) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1297 | INIT_LIST_HEAD(&cic->list); |
| 1298 | cic->cfqq = NULL; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1299 | cic->key = NULL; |
| 1300 | cic->last_end_request = jiffies; |
| 1301 | cic->ttime_total = 0; |
| 1302 | cic->ttime_samples = 0; |
| 1303 | cic->ttime_mean = 0; |
| 1304 | cic->dtor = cfq_free_io_context; |
| 1305 | cic->exit = cfq_exit_io_context; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1306 | } |
| 1307 | |
| 1308 | return cic; |
| 1309 | } |
| 1310 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1311 | static void cfq_init_prio_data(struct cfq_queue *cfqq) |
| 1312 | { |
| 1313 | struct task_struct *tsk = current; |
| 1314 | int ioprio_class; |
| 1315 | |
| 1316 | if (!cfqq->prio_changed) |
| 1317 | return; |
| 1318 | |
| 1319 | ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); |
| 1320 | switch (ioprio_class) { |
| 1321 | default: |
| 1322 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); |
| 1323 | case IOPRIO_CLASS_NONE: |
| 1324 | /* |
| 1325 | * no prio set, place us in the middle of the BE classes |
| 1326 | */ |
| 1327 | cfqq->ioprio = task_nice_ioprio(tsk); |
| 1328 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
| 1329 | break; |
| 1330 | case IOPRIO_CLASS_RT: |
| 1331 | cfqq->ioprio = task_ioprio(tsk); |
| 1332 | cfqq->ioprio_class = IOPRIO_CLASS_RT; |
| 1333 | break; |
| 1334 | case IOPRIO_CLASS_BE: |
| 1335 | cfqq->ioprio = task_ioprio(tsk); |
| 1336 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
| 1337 | break; |
| 1338 | case IOPRIO_CLASS_IDLE: |
| 1339 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; |
| 1340 | cfqq->ioprio = 7; |
| 1341 | cfqq->idle_window = 0; |
| 1342 | break; |
| 1343 | } |
| 1344 | |
| 1345 | /* |
| 1346 | * keep track of original prio settings in case we have to temporarily |
| 1347 | * elevate the priority of this queue |
| 1348 | */ |
| 1349 | cfqq->org_ioprio = cfqq->ioprio; |
| 1350 | cfqq->org_ioprio_class = cfqq->ioprio_class; |
| 1351 | |
| 1352 | if (cfqq->on_rr) |
| 1353 | cfq_resort_rr_list(cfqq, 0); |
| 1354 | |
| 1355 | cfqq->prio_changed = 0; |
| 1356 | } |
| 1357 | |
| 1358 | static inline void changed_ioprio(struct cfq_queue *cfqq) |
| 1359 | { |
| 1360 | if (cfqq) { |
| 1361 | struct cfq_data *cfqd = cfqq->cfqd; |
| 1362 | |
| 1363 | spin_lock(cfqd->queue->queue_lock); |
| 1364 | cfqq->prio_changed = 1; |
| 1365 | cfq_init_prio_data(cfqq); |
| 1366 | spin_unlock(cfqd->queue->queue_lock); |
| 1367 | } |
| 1368 | } |
| 1369 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1370 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1371 | * callback from sys_ioprio_set, irqs are disabled |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1372 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1373 | static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1374 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1375 | struct cfq_io_context *cic = ioc->cic; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1376 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1377 | changed_ioprio(cic->cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1378 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1379 | list_for_each_entry(cic, &cic->list, list) |
| 1380 | changed_ioprio(cic->cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1381 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1382 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1383 | } |
| 1384 | |
| 1385 | static struct cfq_queue * |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1386 | cfq_get_queue(struct cfq_data *cfqd, unsigned int key, int gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1387 | { |
| 1388 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); |
| 1389 | struct cfq_queue *cfqq, *new_cfqq = NULL; |
| 1390 | |
| 1391 | retry: |
| 1392 | cfqq = __cfq_find_cfq_hash(cfqd, key, hashval); |
| 1393 | |
| 1394 | if (!cfqq) { |
| 1395 | if (new_cfqq) { |
| 1396 | cfqq = new_cfqq; |
| 1397 | new_cfqq = NULL; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1398 | } else if (gfp_mask & __GFP_WAIT) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1399 | spin_unlock_irq(cfqd->queue->queue_lock); |
| 1400 | new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); |
| 1401 | spin_lock_irq(cfqd->queue->queue_lock); |
| 1402 | goto retry; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1403 | } else { |
| 1404 | cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); |
| 1405 | if (!cfqq) |
| 1406 | goto out; |
Kiyoshi Ueda | db3b584 | 2005-06-17 16:15:10 +0200 | [diff] [blame] | 1407 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1408 | |
| 1409 | memset(cfqq, 0, sizeof(*cfqq)); |
| 1410 | |
| 1411 | INIT_HLIST_NODE(&cfqq->cfq_hash); |
| 1412 | INIT_LIST_HEAD(&cfqq->cfq_list); |
| 1413 | RB_CLEAR_ROOT(&cfqq->sort_list); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1414 | INIT_LIST_HEAD(&cfqq->fifo); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1415 | |
| 1416 | cfqq->key = key; |
| 1417 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); |
| 1418 | atomic_set(&cfqq->ref, 0); |
| 1419 | cfqq->cfqd = cfqd; |
| 1420 | atomic_inc(&cfqd->ref); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1421 | cfqq->service_last = 0; |
| 1422 | /* |
| 1423 | * set ->slice_left to allow preemption for a new process |
| 1424 | */ |
| 1425 | cfqq->slice_left = 2 * cfqd->cfq_slice_idle; |
| 1426 | cfqq->idle_window = 1; |
| 1427 | cfqq->ioprio = -1; |
| 1428 | cfqq->ioprio_class = -1; |
| 1429 | cfqq->prio_changed = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1430 | } |
| 1431 | |
| 1432 | if (new_cfqq) |
| 1433 | kmem_cache_free(cfq_pool, new_cfqq); |
| 1434 | |
| 1435 | atomic_inc(&cfqq->ref); |
| 1436 | out: |
| 1437 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); |
| 1438 | return cfqq; |
| 1439 | } |
| 1440 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1441 | /* |
| 1442 | * Setup general io context and cfq io context. There can be several cfq |
| 1443 | * io contexts per general io context, if this process is doing io to more |
| 1444 | * than one device managed by cfq. Note that caller is holding a reference to |
| 1445 | * cfqq, so we don't need to worry about it disappearing |
| 1446 | */ |
| 1447 | static struct cfq_io_context * |
| 1448 | cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, int gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1449 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1450 | struct io_context *ioc = NULL; |
| 1451 | struct cfq_io_context *cic; |
| 1452 | |
| 1453 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 1454 | |
| 1455 | ioc = get_io_context(gfp_mask); |
| 1456 | if (!ioc) |
| 1457 | return NULL; |
| 1458 | |
| 1459 | if ((cic = ioc->cic) == NULL) { |
| 1460 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
| 1461 | |
| 1462 | if (cic == NULL) |
| 1463 | goto err; |
| 1464 | |
| 1465 | /* |
| 1466 | * manually increment generic io_context usage count, it |
| 1467 | * cannot go away since we are already holding one ref to it |
| 1468 | */ |
| 1469 | ioc->cic = cic; |
| 1470 | ioc->set_ioprio = cfq_ioc_set_ioprio; |
| 1471 | cic->ioc = ioc; |
| 1472 | cic->key = cfqd; |
| 1473 | atomic_inc(&cfqd->ref); |
| 1474 | } else { |
| 1475 | struct cfq_io_context *__cic; |
| 1476 | |
| 1477 | /* |
| 1478 | * the first cic on the list is actually the head itself |
| 1479 | */ |
| 1480 | if (cic->key == cfqd) |
| 1481 | goto out; |
| 1482 | |
| 1483 | /* |
| 1484 | * cic exists, check if we already are there. linear search |
| 1485 | * should be ok here, the list will usually not be more than |
| 1486 | * 1 or a few entries long |
| 1487 | */ |
| 1488 | list_for_each_entry(__cic, &cic->list, list) { |
| 1489 | /* |
| 1490 | * this process is already holding a reference to |
| 1491 | * this queue, so no need to get one more |
| 1492 | */ |
| 1493 | if (__cic->key == cfqd) { |
| 1494 | cic = __cic; |
| 1495 | goto out; |
| 1496 | } |
| 1497 | } |
| 1498 | |
| 1499 | /* |
| 1500 | * nope, process doesn't have a cic assoicated with this |
| 1501 | * cfqq yet. get a new one and add to list |
| 1502 | */ |
| 1503 | __cic = cfq_alloc_io_context(cfqd, gfp_mask); |
| 1504 | if (__cic == NULL) |
| 1505 | goto err; |
| 1506 | |
| 1507 | __cic->ioc = ioc; |
| 1508 | __cic->key = cfqd; |
| 1509 | atomic_inc(&cfqd->ref); |
| 1510 | list_add(&__cic->list, &cic->list); |
| 1511 | cic = __cic; |
| 1512 | } |
| 1513 | |
| 1514 | out: |
| 1515 | return cic; |
| 1516 | err: |
| 1517 | put_io_context(ioc); |
| 1518 | return NULL; |
| 1519 | } |
| 1520 | |
| 1521 | static void |
| 1522 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) |
| 1523 | { |
| 1524 | unsigned long elapsed, ttime; |
| 1525 | |
| 1526 | /* |
| 1527 | * if this context already has stuff queued, thinktime is from |
| 1528 | * last queue not last end |
| 1529 | */ |
| 1530 | #if 0 |
| 1531 | if (time_after(cic->last_end_request, cic->last_queue)) |
| 1532 | elapsed = jiffies - cic->last_end_request; |
| 1533 | else |
| 1534 | elapsed = jiffies - cic->last_queue; |
| 1535 | #else |
| 1536 | elapsed = jiffies - cic->last_end_request; |
| 1537 | #endif |
| 1538 | |
| 1539 | ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
| 1540 | |
| 1541 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
| 1542 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; |
| 1543 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; |
| 1544 | } |
| 1545 | |
| 1546 | #define sample_valid(samples) ((samples) > 80) |
| 1547 | |
| 1548 | /* |
| 1549 | * Disable idle window if the process thinks too long or seeks so much that |
| 1550 | * it doesn't matter |
| 1551 | */ |
| 1552 | static void |
| 1553 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 1554 | struct cfq_io_context *cic) |
| 1555 | { |
| 1556 | int enable_idle = cfqq->idle_window; |
| 1557 | |
| 1558 | if (!cic->ioc->task || !cfqd->cfq_slice_idle) |
| 1559 | enable_idle = 0; |
| 1560 | else if (sample_valid(cic->ttime_samples)) { |
| 1561 | if (cic->ttime_mean > cfqd->cfq_slice_idle) |
| 1562 | enable_idle = 0; |
| 1563 | else |
| 1564 | enable_idle = 1; |
| 1565 | } |
| 1566 | |
| 1567 | cfqq->idle_window = enable_idle; |
| 1568 | } |
| 1569 | |
| 1570 | |
| 1571 | /* |
| 1572 | * Check if new_cfqq should preempt the currently active queue. Return 0 for |
| 1573 | * no or if we aren't sure, a 1 will cause a preempt. |
| 1574 | */ |
| 1575 | static int |
| 1576 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, |
| 1577 | struct cfq_rq *crq) |
| 1578 | { |
| 1579 | struct cfq_queue *cfqq = cfqd->active_queue; |
| 1580 | |
| 1581 | if (cfq_class_idle(new_cfqq)) |
| 1582 | return 0; |
| 1583 | |
| 1584 | if (!cfqq) |
| 1585 | return 1; |
| 1586 | |
| 1587 | if (cfq_class_idle(cfqq)) |
| 1588 | return 1; |
| 1589 | if (!new_cfqq->wait_request) |
| 1590 | return 0; |
| 1591 | /* |
| 1592 | * if it doesn't have slice left, forget it |
| 1593 | */ |
| 1594 | if (new_cfqq->slice_left < cfqd->cfq_slice_idle) |
| 1595 | return 0; |
| 1596 | if (crq->is_sync && !cfq_cfqq_sync(cfqq)) |
| 1597 | return 1; |
| 1598 | |
| 1599 | return 0; |
| 1600 | } |
| 1601 | |
| 1602 | /* |
| 1603 | * cfqq preempts the active queue. if we allowed preempt with no slice left, |
| 1604 | * let it have half of its nominal slice. |
| 1605 | */ |
| 1606 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 1607 | { |
| 1608 | struct cfq_queue *__cfqq, *next; |
| 1609 | |
| 1610 | list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) |
| 1611 | cfq_resort_rr_list(__cfqq, 1); |
| 1612 | |
| 1613 | if (!cfqq->slice_left) |
| 1614 | cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; |
| 1615 | |
| 1616 | cfqq->slice_end = cfqq->slice_left + jiffies; |
| 1617 | cfq_slice_expired(cfqd, 1); |
| 1618 | __cfq_set_active_queue(cfqd, cfqq); |
| 1619 | } |
| 1620 | |
| 1621 | /* |
| 1622 | * should really be a ll_rw_blk.c helper |
| 1623 | */ |
| 1624 | static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| 1625 | { |
| 1626 | request_queue_t *q = cfqd->queue; |
| 1627 | |
| 1628 | if (!blk_queue_plugged(q)) |
| 1629 | q->request_fn(q); |
| 1630 | else |
| 1631 | __generic_unplug_device(q); |
| 1632 | } |
| 1633 | |
| 1634 | /* |
| 1635 | * Called when a new fs request (crq) is added (to cfqq). Check if there's |
| 1636 | * something we should do about it |
| 1637 | */ |
| 1638 | static void |
| 1639 | cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 1640 | struct cfq_rq *crq) |
| 1641 | { |
| 1642 | const int sync = crq->is_sync; |
| 1643 | |
| 1644 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); |
| 1645 | |
| 1646 | if (sync) { |
| 1647 | struct cfq_io_context *cic = crq->io_context; |
| 1648 | |
| 1649 | cfq_update_io_thinktime(cfqd, cic); |
| 1650 | cfq_update_idle_window(cfqd, cfqq, cic); |
| 1651 | |
| 1652 | cic->last_queue = jiffies; |
| 1653 | } |
| 1654 | |
| 1655 | if (cfqq == cfqd->active_queue) { |
| 1656 | /* |
| 1657 | * if we are waiting for a request for this queue, let it rip |
| 1658 | * immediately and flag that we must not expire this queue |
| 1659 | * just now |
| 1660 | */ |
| 1661 | if (cfqq->wait_request) { |
| 1662 | cfqq->must_dispatch = 1; |
| 1663 | del_timer(&cfqd->idle_slice_timer); |
| 1664 | cfq_start_queueing(cfqd, cfqq); |
| 1665 | } |
| 1666 | } else if (cfq_should_preempt(cfqd, cfqq, crq)) { |
| 1667 | /* |
| 1668 | * not the active queue - expire current slice if it is |
| 1669 | * idle and has expired it's mean thinktime or this new queue |
| 1670 | * has some old slice time left and is of higher priority |
| 1671 | */ |
| 1672 | cfq_preempt_queue(cfqd, cfqq); |
| 1673 | cfqq->must_dispatch = 1; |
| 1674 | cfq_start_queueing(cfqd, cfqq); |
| 1675 | } |
| 1676 | } |
| 1677 | |
| 1678 | static void cfq_enqueue(struct cfq_data *cfqd, struct request *rq) |
| 1679 | { |
| 1680 | struct cfq_rq *crq = RQ_DATA(rq); |
| 1681 | struct cfq_queue *cfqq = crq->cfq_queue; |
| 1682 | |
| 1683 | cfq_init_prio_data(cfqq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1684 | |
| 1685 | cfq_add_crq_rb(crq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1686 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1687 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
| 1688 | |
| 1689 | if (rq_mergeable(rq)) { |
| 1690 | cfq_add_crq_hash(cfqd, crq); |
| 1691 | |
| 1692 | if (!cfqd->queue->last_merge) |
| 1693 | cfqd->queue->last_merge = rq; |
| 1694 | } |
| 1695 | |
| 1696 | cfq_crq_enqueued(cfqd, cfqq, crq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1697 | } |
| 1698 | |
| 1699 | static void |
| 1700 | cfq_insert_request(request_queue_t *q, struct request *rq, int where) |
| 1701 | { |
| 1702 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1703 | |
| 1704 | switch (where) { |
| 1705 | case ELEVATOR_INSERT_BACK: |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1706 | while (cfq_dispatch_requests(q, INT_MAX, 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1707 | ; |
| 1708 | list_add_tail(&rq->queuelist, &q->queue_head); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1709 | /* |
| 1710 | * If we were idling with pending requests on |
| 1711 | * inactive cfqqs, force dispatching will |
| 1712 | * remove the idle timer and the queue won't |
| 1713 | * be kicked by __make_request() afterward. |
| 1714 | * Kick it here. |
| 1715 | */ |
| 1716 | kblockd_schedule_work(&cfqd->unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1717 | break; |
| 1718 | case ELEVATOR_INSERT_FRONT: |
| 1719 | list_add(&rq->queuelist, &q->queue_head); |
| 1720 | break; |
| 1721 | case ELEVATOR_INSERT_SORT: |
| 1722 | BUG_ON(!blk_fs_request(rq)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1723 | cfq_enqueue(cfqd, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1724 | break; |
| 1725 | default: |
| 1726 | printk("%s: bad insert point %d\n", __FUNCTION__,where); |
| 1727 | return; |
| 1728 | } |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1729 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1730 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1731 | static inline int cfq_pending_requests(struct cfq_data *cfqd) |
| 1732 | { |
| 1733 | return !list_empty(&cfqd->queue->queue_head) || cfqd->busy_queues; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1734 | } |
| 1735 | |
| 1736 | static int cfq_queue_empty(request_queue_t *q) |
| 1737 | { |
| 1738 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 1739 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1740 | return !cfq_pending_requests(cfqd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1741 | } |
| 1742 | |
| 1743 | static void cfq_completed_request(request_queue_t *q, struct request *rq) |
| 1744 | { |
| 1745 | struct cfq_rq *crq = RQ_DATA(rq); |
| 1746 | struct cfq_queue *cfqq; |
| 1747 | |
| 1748 | if (unlikely(!blk_fs_request(rq))) |
| 1749 | return; |
| 1750 | |
| 1751 | cfqq = crq->cfq_queue; |
| 1752 | |
| 1753 | if (crq->in_flight) { |
| 1754 | WARN_ON(!cfqq->in_flight); |
| 1755 | cfqq->in_flight--; |
| 1756 | } |
| 1757 | |
| 1758 | cfq_account_completion(cfqq, crq); |
| 1759 | } |
| 1760 | |
| 1761 | static struct request * |
| 1762 | cfq_former_request(request_queue_t *q, struct request *rq) |
| 1763 | { |
| 1764 | struct cfq_rq *crq = RQ_DATA(rq); |
| 1765 | struct rb_node *rbprev = rb_prev(&crq->rb_node); |
| 1766 | |
| 1767 | if (rbprev) |
| 1768 | return rb_entry_crq(rbprev)->request; |
| 1769 | |
| 1770 | return NULL; |
| 1771 | } |
| 1772 | |
| 1773 | static struct request * |
| 1774 | cfq_latter_request(request_queue_t *q, struct request *rq) |
| 1775 | { |
| 1776 | struct cfq_rq *crq = RQ_DATA(rq); |
| 1777 | struct rb_node *rbnext = rb_next(&crq->rb_node); |
| 1778 | |
| 1779 | if (rbnext) |
| 1780 | return rb_entry_crq(rbnext)->request; |
| 1781 | |
| 1782 | return NULL; |
| 1783 | } |
| 1784 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1785 | /* |
| 1786 | * we temporarily boost lower priority queues if they are holding fs exclusive |
| 1787 | * resources. they are boosted to normal prio (CLASS_BE/4) |
| 1788 | */ |
| 1789 | static void cfq_prio_boost(struct cfq_queue *cfqq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1790 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1791 | const int ioprio_class = cfqq->ioprio_class; |
| 1792 | const int ioprio = cfqq->ioprio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1793 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1794 | if (has_fs_excl()) { |
| 1795 | /* |
| 1796 | * boost idle prio on transactions that would lock out other |
| 1797 | * users of the filesystem |
| 1798 | */ |
| 1799 | if (cfq_class_idle(cfqq)) |
| 1800 | cfqq->ioprio_class = IOPRIO_CLASS_BE; |
| 1801 | if (cfqq->ioprio > IOPRIO_NORM) |
| 1802 | cfqq->ioprio = IOPRIO_NORM; |
| 1803 | } else { |
| 1804 | /* |
| 1805 | * check if we need to unboost the queue |
| 1806 | */ |
| 1807 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) |
| 1808 | cfqq->ioprio_class = cfqq->org_ioprio_class; |
| 1809 | if (cfqq->ioprio != cfqq->org_ioprio) |
| 1810 | cfqq->ioprio = cfqq->org_ioprio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1811 | } |
| 1812 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1813 | /* |
| 1814 | * refile between round-robin lists if we moved the priority class |
| 1815 | */ |
| 1816 | if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && |
| 1817 | cfqq->on_rr) |
| 1818 | cfq_resort_rr_list(cfqq, 0); |
| 1819 | } |
| 1820 | |
| 1821 | static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
| 1822 | { |
| 1823 | if (rw == READ || process_sync(task)) |
| 1824 | return task->pid; |
| 1825 | |
| 1826 | return CFQ_KEY_ASYNC; |
| 1827 | } |
| 1828 | |
| 1829 | static inline int |
| 1830 | __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| 1831 | struct task_struct *task, int rw) |
| 1832 | { |
| 1833 | if (cfqq->wait_request && cfqq->must_alloc) |
| 1834 | return ELV_MQUEUE_MUST; |
| 1835 | |
| 1836 | return ELV_MQUEUE_MAY; |
| 1837 | #if 0 |
| 1838 | if (!cfqq || task->flags & PF_MEMALLOC) |
| 1839 | return ELV_MQUEUE_MAY; |
| 1840 | if (!cfqq->allocated[rw] || cfqq->must_alloc) { |
| 1841 | if (cfqq->wait_request) |
| 1842 | return ELV_MQUEUE_MUST; |
| 1843 | |
| 1844 | /* |
| 1845 | * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we |
| 1846 | * can quickly flood the queue with writes from a single task |
| 1847 | */ |
| 1848 | if (rw == READ || !cfqq->must_alloc_slice) { |
| 1849 | cfqq->must_alloc_slice = 1; |
| 1850 | return ELV_MQUEUE_MUST; |
| 1851 | } |
| 1852 | |
| 1853 | return ELV_MQUEUE_MAY; |
| 1854 | } |
| 1855 | if (cfq_class_idle(cfqq)) |
| 1856 | return ELV_MQUEUE_NO; |
| 1857 | if (cfqq->allocated[rw] >= cfqd->max_queued) { |
| 1858 | struct io_context *ioc = get_io_context(GFP_ATOMIC); |
| 1859 | int ret = ELV_MQUEUE_NO; |
| 1860 | |
| 1861 | if (ioc && ioc->nr_batch_requests) |
| 1862 | ret = ELV_MQUEUE_MAY; |
| 1863 | |
| 1864 | put_io_context(ioc); |
| 1865 | return ret; |
| 1866 | } |
| 1867 | |
| 1868 | return ELV_MQUEUE_MAY; |
| 1869 | #endif |
| 1870 | } |
| 1871 | |
| 1872 | static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) |
| 1873 | { |
| 1874 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 1875 | struct task_struct *tsk = current; |
| 1876 | struct cfq_queue *cfqq; |
| 1877 | |
| 1878 | /* |
| 1879 | * don't force setup of a queue from here, as a call to may_queue |
| 1880 | * does not necessarily imply that a request actually will be queued. |
| 1881 | * so just lookup a possibly existing queue, or return 'may queue' |
| 1882 | * if that fails |
| 1883 | */ |
| 1884 | cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw)); |
| 1885 | if (cfqq) { |
| 1886 | cfq_init_prio_data(cfqq); |
| 1887 | cfq_prio_boost(cfqq); |
| 1888 | |
| 1889 | return __cfq_may_queue(cfqd, cfqq, tsk, rw); |
| 1890 | } |
| 1891 | |
| 1892 | return ELV_MQUEUE_MAY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1893 | } |
| 1894 | |
| 1895 | static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) |
| 1896 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1897 | struct cfq_data *cfqd = q->elevator->elevator_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1898 | struct request_list *rl = &q->rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1899 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1900 | if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) { |
| 1901 | smp_mb(); |
| 1902 | if (waitqueue_active(&rl->wait[READ])) |
| 1903 | wake_up(&rl->wait[READ]); |
| 1904 | } |
| 1905 | |
| 1906 | if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) { |
| 1907 | smp_mb(); |
| 1908 | if (waitqueue_active(&rl->wait[WRITE])) |
| 1909 | wake_up(&rl->wait[WRITE]); |
| 1910 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1911 | } |
| 1912 | |
| 1913 | /* |
| 1914 | * queue lock held here |
| 1915 | */ |
| 1916 | static void cfq_put_request(request_queue_t *q, struct request *rq) |
| 1917 | { |
| 1918 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 1919 | struct cfq_rq *crq = RQ_DATA(rq); |
| 1920 | |
| 1921 | if (crq) { |
| 1922 | struct cfq_queue *cfqq = crq->cfq_queue; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1923 | const int rw = rq_data_dir(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1924 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1925 | BUG_ON(!cfqq->allocated[rw]); |
| 1926 | cfqq->allocated[rw]--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1927 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1928 | put_io_context(crq->io_context->ioc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1929 | |
| 1930 | mempool_free(crq, cfqd->crq_pool); |
| 1931 | rq->elevator_private = NULL; |
| 1932 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1933 | cfq_check_waiters(q, cfqq); |
| 1934 | cfq_put_queue(cfqq); |
| 1935 | } |
| 1936 | } |
| 1937 | |
| 1938 | /* |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1939 | * Allocate cfq data structures associated with this request. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1940 | */ |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1941 | static int |
| 1942 | cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, |
| 1943 | int gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1944 | { |
| 1945 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 1946 | struct cfq_io_context *cic; |
| 1947 | const int rw = rq_data_dir(rq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1948 | struct cfq_queue *cfqq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1949 | struct cfq_rq *crq; |
| 1950 | unsigned long flags; |
| 1951 | |
| 1952 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 1953 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1954 | cic = cfq_get_io_context(cfqd, cfq_queue_pid(current, rw), gfp_mask); |
| 1955 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1956 | spin_lock_irqsave(q->queue_lock, flags); |
| 1957 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1958 | if (!cic) |
| 1959 | goto queue_fail; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1960 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1961 | if (!cic->cfqq) { |
| 1962 | cfqq = cfq_get_queue(cfqd, current->pid, gfp_mask); |
| 1963 | if (!cfqq) |
| 1964 | goto queue_fail; |
| 1965 | |
| 1966 | cic->cfqq = cfqq; |
| 1967 | } else |
| 1968 | cfqq = cic->cfqq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1969 | |
| 1970 | cfqq->allocated[rw]++; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1971 | cfqq->must_alloc = 0; |
| 1972 | cfqd->rq_starved = 0; |
| 1973 | atomic_inc(&cfqq->ref); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1974 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 1975 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1976 | crq = mempool_alloc(cfqd->crq_pool, gfp_mask); |
| 1977 | if (crq) { |
| 1978 | RB_CLEAR(&crq->rb_node); |
| 1979 | crq->rb_key = 0; |
| 1980 | crq->request = rq; |
| 1981 | INIT_HLIST_NODE(&crq->hash); |
| 1982 | crq->cfq_queue = cfqq; |
| 1983 | crq->io_context = cic; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1984 | crq->in_flight = crq->accounted = 0; |
| 1985 | crq->is_sync = (rw == READ || process_sync(current)); |
| 1986 | crq->requeued = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1987 | rq->elevator_private = crq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1988 | return 0; |
| 1989 | } |
| 1990 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1991 | spin_lock_irqsave(q->queue_lock, flags); |
| 1992 | cfqq->allocated[rw]--; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1993 | if (!(cfqq->allocated[0] + cfqq->allocated[1])) |
| 1994 | cfqq->must_alloc = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1995 | cfq_put_queue(cfqq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 1996 | queue_fail: |
| 1997 | if (cic) |
| 1998 | put_io_context(cic->ioc); |
| 1999 | /* |
| 2000 | * mark us rq allocation starved. we need to kickstart the process |
| 2001 | * ourselves if there are no pending requests that can do it for us. |
| 2002 | * that would be an extremely rare OOM situation |
| 2003 | */ |
| 2004 | cfqd->rq_starved = 1; |
| 2005 | kblockd_schedule_work(&cfqd->unplug_work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2006 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 2007 | return 1; |
| 2008 | } |
| 2009 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2010 | static void cfq_kick_queue(void *data) |
| 2011 | { |
| 2012 | request_queue_t *q = data; |
| 2013 | struct cfq_data *cfqd = q->elevator->elevator_data; |
| 2014 | unsigned long flags; |
| 2015 | |
| 2016 | spin_lock_irqsave(q->queue_lock, flags); |
| 2017 | |
| 2018 | if (cfqd->rq_starved) { |
| 2019 | struct request_list *rl = &q->rq; |
| 2020 | |
| 2021 | /* |
| 2022 | * we aren't guaranteed to get a request after this, but we |
| 2023 | * have to be opportunistic |
| 2024 | */ |
| 2025 | smp_mb(); |
| 2026 | if (waitqueue_active(&rl->wait[READ])) |
| 2027 | wake_up(&rl->wait[READ]); |
| 2028 | if (waitqueue_active(&rl->wait[WRITE])) |
| 2029 | wake_up(&rl->wait[WRITE]); |
| 2030 | } |
| 2031 | |
| 2032 | blk_remove_plug(q); |
| 2033 | q->request_fn(q); |
| 2034 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 2035 | } |
| 2036 | |
| 2037 | /* |
| 2038 | * Timer running if the active_queue is currently idling inside its time slice |
| 2039 | */ |
| 2040 | static void cfq_idle_slice_timer(unsigned long data) |
| 2041 | { |
| 2042 | struct cfq_data *cfqd = (struct cfq_data *) data; |
| 2043 | struct cfq_queue *cfqq; |
| 2044 | unsigned long flags; |
| 2045 | |
| 2046 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
| 2047 | |
| 2048 | if ((cfqq = cfqd->active_queue) != NULL) { |
| 2049 | unsigned long now = jiffies; |
| 2050 | |
| 2051 | /* |
| 2052 | * expired |
| 2053 | */ |
| 2054 | if (time_after(now, cfqq->slice_end)) |
| 2055 | goto expire; |
| 2056 | |
| 2057 | /* |
| 2058 | * only expire and reinvoke request handler, if there are |
| 2059 | * other queues with pending requests |
| 2060 | */ |
| 2061 | if (!cfq_pending_requests(cfqd)) { |
| 2062 | cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end); |
| 2063 | add_timer(&cfqd->idle_slice_timer); |
| 2064 | goto out_cont; |
| 2065 | } |
| 2066 | |
| 2067 | /* |
| 2068 | * not expired and it has a request pending, let it dispatch |
| 2069 | */ |
| 2070 | if (!RB_EMPTY(&cfqq->sort_list)) { |
| 2071 | cfqq->must_dispatch = 1; |
| 2072 | goto out_kick; |
| 2073 | } |
| 2074 | } |
| 2075 | expire: |
| 2076 | cfq_slice_expired(cfqd, 0); |
| 2077 | out_kick: |
| 2078 | if (cfq_pending_requests(cfqd)) |
| 2079 | kblockd_schedule_work(&cfqd->unplug_work); |
| 2080 | out_cont: |
| 2081 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
| 2082 | } |
| 2083 | |
| 2084 | /* |
| 2085 | * Timer running if an idle class queue is waiting for service |
| 2086 | */ |
| 2087 | static void cfq_idle_class_timer(unsigned long data) |
| 2088 | { |
| 2089 | struct cfq_data *cfqd = (struct cfq_data *) data; |
| 2090 | unsigned long flags, end; |
| 2091 | |
| 2092 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); |
| 2093 | |
| 2094 | /* |
| 2095 | * race with a non-idle queue, reset timer |
| 2096 | */ |
| 2097 | end = cfqd->last_end_request + CFQ_IDLE_GRACE; |
| 2098 | if (!time_after_eq(jiffies, end)) { |
| 2099 | cfqd->idle_class_timer.expires = end; |
| 2100 | add_timer(&cfqd->idle_class_timer); |
| 2101 | } else |
| 2102 | kblockd_schedule_work(&cfqd->unplug_work); |
| 2103 | |
| 2104 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |
| 2105 | } |
| 2106 | |
| 2107 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2108 | static void cfq_put_cfqd(struct cfq_data *cfqd) |
| 2109 | { |
| 2110 | request_queue_t *q = cfqd->queue; |
| 2111 | |
| 2112 | if (!atomic_dec_and_test(&cfqd->ref)) |
| 2113 | return; |
| 2114 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2115 | blk_sync_queue(q); |
| 2116 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2117 | blk_put_queue(q); |
| 2118 | |
| 2119 | mempool_destroy(cfqd->crq_pool); |
| 2120 | kfree(cfqd->crq_hash); |
| 2121 | kfree(cfqd->cfq_hash); |
| 2122 | kfree(cfqd); |
| 2123 | } |
| 2124 | |
| 2125 | static void cfq_exit_queue(elevator_t *e) |
| 2126 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2127 | struct cfq_data *cfqd = e->elevator_data; |
| 2128 | |
| 2129 | del_timer_sync(&cfqd->idle_slice_timer); |
| 2130 | del_timer_sync(&cfqd->idle_class_timer); |
| 2131 | cfq_put_cfqd(cfqd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2132 | } |
| 2133 | |
| 2134 | static int cfq_init_queue(request_queue_t *q, elevator_t *e) |
| 2135 | { |
| 2136 | struct cfq_data *cfqd; |
| 2137 | int i; |
| 2138 | |
| 2139 | cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); |
| 2140 | if (!cfqd) |
| 2141 | return -ENOMEM; |
| 2142 | |
| 2143 | memset(cfqd, 0, sizeof(*cfqd)); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2144 | |
| 2145 | for (i = 0; i < CFQ_PRIO_LISTS; i++) |
| 2146 | INIT_LIST_HEAD(&cfqd->rr_list[i]); |
| 2147 | |
| 2148 | INIT_LIST_HEAD(&cfqd->busy_rr); |
| 2149 | INIT_LIST_HEAD(&cfqd->cur_rr); |
| 2150 | INIT_LIST_HEAD(&cfqd->idle_rr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2151 | INIT_LIST_HEAD(&cfqd->empty_list); |
| 2152 | |
| 2153 | cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); |
| 2154 | if (!cfqd->crq_hash) |
| 2155 | goto out_crqhash; |
| 2156 | |
| 2157 | cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); |
| 2158 | if (!cfqd->cfq_hash) |
| 2159 | goto out_cfqhash; |
| 2160 | |
| 2161 | cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool); |
| 2162 | if (!cfqd->crq_pool) |
| 2163 | goto out_crqpool; |
| 2164 | |
| 2165 | for (i = 0; i < CFQ_MHASH_ENTRIES; i++) |
| 2166 | INIT_HLIST_HEAD(&cfqd->crq_hash[i]); |
| 2167 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) |
| 2168 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); |
| 2169 | |
| 2170 | e->elevator_data = cfqd; |
| 2171 | |
| 2172 | cfqd->queue = q; |
| 2173 | atomic_inc(&q->refcnt); |
| 2174 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2175 | cfqd->max_queued = q->nr_requests / 4; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2176 | q->nr_batching = cfq_queued; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2177 | |
| 2178 | init_timer(&cfqd->idle_slice_timer); |
| 2179 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; |
| 2180 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; |
| 2181 | |
| 2182 | init_timer(&cfqd->idle_class_timer); |
| 2183 | cfqd->idle_class_timer.function = cfq_idle_class_timer; |
| 2184 | cfqd->idle_class_timer.data = (unsigned long) cfqd; |
| 2185 | |
| 2186 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); |
| 2187 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2188 | atomic_set(&cfqd->ref, 1); |
| 2189 | |
| 2190 | cfqd->cfq_queued = cfq_queued; |
| 2191 | cfqd->cfq_quantum = cfq_quantum; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2192 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
| 2193 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2194 | cfqd->cfq_back_max = cfq_back_max; |
| 2195 | cfqd->cfq_back_penalty = cfq_back_penalty; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2196 | cfqd->cfq_slice[0] = cfq_slice_async; |
| 2197 | cfqd->cfq_slice[1] = cfq_slice_sync; |
| 2198 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; |
| 2199 | cfqd->cfq_slice_idle = cfq_slice_idle; |
| 2200 | cfqd->cfq_max_depth = cfq_max_depth; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2201 | return 0; |
| 2202 | out_crqpool: |
| 2203 | kfree(cfqd->cfq_hash); |
| 2204 | out_cfqhash: |
| 2205 | kfree(cfqd->crq_hash); |
| 2206 | out_crqhash: |
| 2207 | kfree(cfqd); |
| 2208 | return -ENOMEM; |
| 2209 | } |
| 2210 | |
| 2211 | static void cfq_slab_kill(void) |
| 2212 | { |
| 2213 | if (crq_pool) |
| 2214 | kmem_cache_destroy(crq_pool); |
| 2215 | if (cfq_pool) |
| 2216 | kmem_cache_destroy(cfq_pool); |
| 2217 | if (cfq_ioc_pool) |
| 2218 | kmem_cache_destroy(cfq_ioc_pool); |
| 2219 | } |
| 2220 | |
| 2221 | static int __init cfq_slab_setup(void) |
| 2222 | { |
| 2223 | crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, |
| 2224 | NULL, NULL); |
| 2225 | if (!crq_pool) |
| 2226 | goto fail; |
| 2227 | |
| 2228 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, |
| 2229 | NULL, NULL); |
| 2230 | if (!cfq_pool) |
| 2231 | goto fail; |
| 2232 | |
| 2233 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", |
| 2234 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); |
| 2235 | if (!cfq_ioc_pool) |
| 2236 | goto fail; |
| 2237 | |
| 2238 | return 0; |
| 2239 | fail: |
| 2240 | cfq_slab_kill(); |
| 2241 | return -ENOMEM; |
| 2242 | } |
| 2243 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2244 | /* |
| 2245 | * sysfs parts below --> |
| 2246 | */ |
| 2247 | struct cfq_fs_entry { |
| 2248 | struct attribute attr; |
| 2249 | ssize_t (*show)(struct cfq_data *, char *); |
| 2250 | ssize_t (*store)(struct cfq_data *, const char *, size_t); |
| 2251 | }; |
| 2252 | |
| 2253 | static ssize_t |
| 2254 | cfq_var_show(unsigned int var, char *page) |
| 2255 | { |
| 2256 | return sprintf(page, "%d\n", var); |
| 2257 | } |
| 2258 | |
| 2259 | static ssize_t |
| 2260 | cfq_var_store(unsigned int *var, const char *page, size_t count) |
| 2261 | { |
| 2262 | char *p = (char *) page; |
| 2263 | |
| 2264 | *var = simple_strtoul(p, &p, 10); |
| 2265 | return count; |
| 2266 | } |
| 2267 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2268 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
| 2269 | static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \ |
| 2270 | { \ |
| 2271 | unsigned int __data = __VAR; \ |
| 2272 | if (__CONV) \ |
| 2273 | __data = jiffies_to_msecs(__data); \ |
| 2274 | return cfq_var_show(__data, (page)); \ |
| 2275 | } |
| 2276 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); |
| 2277 | SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2278 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
| 2279 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2280 | SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); |
| 2281 | SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2282 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
| 2283 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); |
| 2284 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); |
| 2285 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); |
| 2286 | SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2287 | #undef SHOW_FUNCTION |
| 2288 | |
| 2289 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ |
| 2290 | static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \ |
| 2291 | { \ |
| 2292 | unsigned int __data; \ |
| 2293 | int ret = cfq_var_store(&__data, (page), count); \ |
| 2294 | if (__data < (MIN)) \ |
| 2295 | __data = (MIN); \ |
| 2296 | else if (__data > (MAX)) \ |
| 2297 | __data = (MAX); \ |
| 2298 | if (__CONV) \ |
| 2299 | *(__PTR) = msecs_to_jiffies(__data); \ |
| 2300 | else \ |
| 2301 | *(__PTR) = __data; \ |
| 2302 | return ret; \ |
| 2303 | } |
| 2304 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); |
| 2305 | STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2306 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); |
| 2307 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2308 | STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
| 2309 | STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2310 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
| 2311 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); |
| 2312 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); |
| 2313 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); |
| 2314 | STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2315 | #undef STORE_FUNCTION |
| 2316 | |
| 2317 | static struct cfq_fs_entry cfq_quantum_entry = { |
| 2318 | .attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR }, |
| 2319 | .show = cfq_quantum_show, |
| 2320 | .store = cfq_quantum_store, |
| 2321 | }; |
| 2322 | static struct cfq_fs_entry cfq_queued_entry = { |
| 2323 | .attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR }, |
| 2324 | .show = cfq_queued_show, |
| 2325 | .store = cfq_queued_store, |
| 2326 | }; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2327 | static struct cfq_fs_entry cfq_fifo_expire_sync_entry = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2328 | .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2329 | .show = cfq_fifo_expire_sync_show, |
| 2330 | .store = cfq_fifo_expire_sync_store, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2331 | }; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2332 | static struct cfq_fs_entry cfq_fifo_expire_async_entry = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2333 | .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2334 | .show = cfq_fifo_expire_async_show, |
| 2335 | .store = cfq_fifo_expire_async_store, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2336 | }; |
| 2337 | static struct cfq_fs_entry cfq_back_max_entry = { |
| 2338 | .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR }, |
| 2339 | .show = cfq_back_max_show, |
| 2340 | .store = cfq_back_max_store, |
| 2341 | }; |
| 2342 | static struct cfq_fs_entry cfq_back_penalty_entry = { |
| 2343 | .attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR }, |
| 2344 | .show = cfq_back_penalty_show, |
| 2345 | .store = cfq_back_penalty_store, |
| 2346 | }; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2347 | static struct cfq_fs_entry cfq_slice_sync_entry = { |
| 2348 | .attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR }, |
| 2349 | .show = cfq_slice_sync_show, |
| 2350 | .store = cfq_slice_sync_store, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2351 | }; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2352 | static struct cfq_fs_entry cfq_slice_async_entry = { |
| 2353 | .attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR }, |
| 2354 | .show = cfq_slice_async_show, |
| 2355 | .store = cfq_slice_async_store, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2356 | }; |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2357 | static struct cfq_fs_entry cfq_slice_async_rq_entry = { |
| 2358 | .attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR }, |
| 2359 | .show = cfq_slice_async_rq_show, |
| 2360 | .store = cfq_slice_async_rq_store, |
| 2361 | }; |
| 2362 | static struct cfq_fs_entry cfq_slice_idle_entry = { |
| 2363 | .attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR }, |
| 2364 | .show = cfq_slice_idle_show, |
| 2365 | .store = cfq_slice_idle_store, |
| 2366 | }; |
| 2367 | static struct cfq_fs_entry cfq_max_depth_entry = { |
| 2368 | .attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR }, |
| 2369 | .show = cfq_max_depth_show, |
| 2370 | .store = cfq_max_depth_store, |
| 2371 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2372 | static struct attribute *default_attrs[] = { |
| 2373 | &cfq_quantum_entry.attr, |
| 2374 | &cfq_queued_entry.attr, |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2375 | &cfq_fifo_expire_sync_entry.attr, |
| 2376 | &cfq_fifo_expire_async_entry.attr, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2377 | &cfq_back_max_entry.attr, |
| 2378 | &cfq_back_penalty_entry.attr, |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2379 | &cfq_slice_sync_entry.attr, |
| 2380 | &cfq_slice_async_entry.attr, |
| 2381 | &cfq_slice_async_rq_entry.attr, |
| 2382 | &cfq_slice_idle_entry.attr, |
| 2383 | &cfq_max_depth_entry.attr, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2384 | NULL, |
| 2385 | }; |
| 2386 | |
| 2387 | #define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr) |
| 2388 | |
| 2389 | static ssize_t |
| 2390 | cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page) |
| 2391 | { |
| 2392 | elevator_t *e = container_of(kobj, elevator_t, kobj); |
| 2393 | struct cfq_fs_entry *entry = to_cfq(attr); |
| 2394 | |
| 2395 | if (!entry->show) |
Dmitry Torokhov | 6c1852a | 2005-04-29 01:26:06 -0500 | [diff] [blame] | 2396 | return -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2397 | |
| 2398 | return entry->show(e->elevator_data, page); |
| 2399 | } |
| 2400 | |
| 2401 | static ssize_t |
| 2402 | cfq_attr_store(struct kobject *kobj, struct attribute *attr, |
| 2403 | const char *page, size_t length) |
| 2404 | { |
| 2405 | elevator_t *e = container_of(kobj, elevator_t, kobj); |
| 2406 | struct cfq_fs_entry *entry = to_cfq(attr); |
| 2407 | |
| 2408 | if (!entry->store) |
Dmitry Torokhov | 6c1852a | 2005-04-29 01:26:06 -0500 | [diff] [blame] | 2409 | return -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2410 | |
| 2411 | return entry->store(e->elevator_data, page, length); |
| 2412 | } |
| 2413 | |
| 2414 | static struct sysfs_ops cfq_sysfs_ops = { |
| 2415 | .show = cfq_attr_show, |
| 2416 | .store = cfq_attr_store, |
| 2417 | }; |
| 2418 | |
| 2419 | static struct kobj_type cfq_ktype = { |
| 2420 | .sysfs_ops = &cfq_sysfs_ops, |
| 2421 | .default_attrs = default_attrs, |
| 2422 | }; |
| 2423 | |
| 2424 | static struct elevator_type iosched_cfq = { |
| 2425 | .ops = { |
| 2426 | .elevator_merge_fn = cfq_merge, |
| 2427 | .elevator_merged_fn = cfq_merged_request, |
| 2428 | .elevator_merge_req_fn = cfq_merged_requests, |
| 2429 | .elevator_next_req_fn = cfq_next_request, |
| 2430 | .elevator_add_req_fn = cfq_insert_request, |
| 2431 | .elevator_remove_req_fn = cfq_remove_request, |
| 2432 | .elevator_requeue_req_fn = cfq_requeue_request, |
| 2433 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
| 2434 | .elevator_queue_empty_fn = cfq_queue_empty, |
| 2435 | .elevator_completed_req_fn = cfq_completed_request, |
| 2436 | .elevator_former_req_fn = cfq_former_request, |
| 2437 | .elevator_latter_req_fn = cfq_latter_request, |
| 2438 | .elevator_set_req_fn = cfq_set_request, |
| 2439 | .elevator_put_req_fn = cfq_put_request, |
| 2440 | .elevator_may_queue_fn = cfq_may_queue, |
| 2441 | .elevator_init_fn = cfq_init_queue, |
| 2442 | .elevator_exit_fn = cfq_exit_queue, |
| 2443 | }, |
| 2444 | .elevator_ktype = &cfq_ktype, |
| 2445 | .elevator_name = "cfq", |
| 2446 | .elevator_owner = THIS_MODULE, |
| 2447 | }; |
| 2448 | |
| 2449 | static int __init cfq_init(void) |
| 2450 | { |
| 2451 | int ret; |
| 2452 | |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2453 | /* |
| 2454 | * could be 0 on HZ < 1000 setups |
| 2455 | */ |
| 2456 | if (!cfq_slice_async) |
| 2457 | cfq_slice_async = 1; |
| 2458 | if (!cfq_slice_idle) |
| 2459 | cfq_slice_idle = 1; |
| 2460 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2461 | if (cfq_slab_setup()) |
| 2462 | return -ENOMEM; |
| 2463 | |
| 2464 | ret = elv_register(&iosched_cfq); |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2465 | if (ret) |
| 2466 | cfq_slab_kill(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2467 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2468 | return ret; |
| 2469 | } |
| 2470 | |
| 2471 | static void __exit cfq_exit(void) |
| 2472 | { |
Jens Axboe | 22e2c50 | 2005-06-27 10:55:12 +0200 | [diff] [blame] | 2473 | struct task_struct *g, *p; |
| 2474 | unsigned long flags; |
| 2475 | |
| 2476 | read_lock_irqsave(&tasklist_lock, flags); |
| 2477 | |
| 2478 | /* |
| 2479 | * iterate each process in the system, removing our io_context |
| 2480 | */ |
| 2481 | do_each_thread(g, p) { |
| 2482 | struct io_context *ioc = p->io_context; |
| 2483 | |
| 2484 | if (ioc && ioc->cic) { |
| 2485 | ioc->cic->exit(ioc->cic); |
| 2486 | cfq_free_io_context(ioc->cic); |
| 2487 | ioc->cic = NULL; |
| 2488 | } |
| 2489 | } while_each_thread(g, p); |
| 2490 | |
| 2491 | read_unlock_irqrestore(&tasklist_lock, flags); |
| 2492 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2493 | cfq_slab_kill(); |
| 2494 | elv_unregister(&iosched_cfq); |
| 2495 | } |
| 2496 | |
| 2497 | module_init(cfq_init); |
| 2498 | module_exit(cfq_exit); |
| 2499 | |
| 2500 | MODULE_AUTHOR("Jens Axboe"); |
| 2501 | MODULE_LICENSE("GPL"); |
| 2502 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |