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