]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
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> | |
24 | ||
25 | static unsigned long max_elapsed_crq; | |
26 | static unsigned long max_elapsed_dispatch; | |
27 | ||
28 | /* | |
29 | * tunables | |
30 | */ | |
31 | static int cfq_quantum = 4; /* max queue in one round of service */ | |
32 | static int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ | |
33 | static int cfq_service = HZ; /* period over which service is avg */ | |
34 | static int cfq_fifo_expire_r = HZ / 2; /* fifo timeout for sync requests */ | |
35 | static int cfq_fifo_expire_w = 5 * HZ; /* fifo timeout for async requests */ | |
36 | static int cfq_fifo_rate = HZ / 8; /* fifo expiry rate */ | |
37 | static int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ | |
38 | static int cfq_back_penalty = 2; /* penalty of a backwards seek */ | |
39 | ||
40 | /* | |
41 | * for the hash of cfqq inside the cfqd | |
42 | */ | |
43 | #define CFQ_QHASH_SHIFT 6 | |
44 | #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) | |
45 | #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) | |
46 | ||
47 | /* | |
48 | * for the hash of crq inside the cfqq | |
49 | */ | |
50 | #define CFQ_MHASH_SHIFT 6 | |
51 | #define CFQ_MHASH_BLOCK(sec) ((sec) >> 3) | |
52 | #define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT) | |
53 | #define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT) | |
54 | #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) | |
55 | #define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash) | |
56 | ||
57 | #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) | |
58 | ||
59 | #define RQ_DATA(rq) (rq)->elevator_private | |
60 | ||
61 | /* | |
62 | * rb-tree defines | |
63 | */ | |
64 | #define RB_NONE (2) | |
65 | #define RB_EMPTY(node) ((node)->rb_node == NULL) | |
66 | #define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE | |
67 | #define RB_CLEAR(node) do { \ | |
68 | (node)->rb_parent = NULL; \ | |
69 | RB_CLEAR_COLOR((node)); \ | |
70 | (node)->rb_right = NULL; \ | |
71 | (node)->rb_left = NULL; \ | |
72 | } while (0) | |
73 | #define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL) | |
74 | #define ON_RB(node) ((node)->rb_color != RB_NONE) | |
75 | #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) | |
76 | #define rq_rb_key(rq) (rq)->sector | |
77 | ||
78 | /* | |
79 | * threshold for switching off non-tag accounting | |
80 | */ | |
81 | #define CFQ_MAX_TAG (4) | |
82 | ||
83 | /* | |
84 | * sort key types and names | |
85 | */ | |
86 | enum { | |
87 | CFQ_KEY_PGID, | |
88 | CFQ_KEY_TGID, | |
89 | CFQ_KEY_UID, | |
90 | CFQ_KEY_GID, | |
91 | CFQ_KEY_LAST, | |
92 | }; | |
93 | ||
94 | static char *cfq_key_types[] = { "pgid", "tgid", "uid", "gid", NULL }; | |
95 | ||
96 | static kmem_cache_t *crq_pool; | |
97 | static kmem_cache_t *cfq_pool; | |
98 | static kmem_cache_t *cfq_ioc_pool; | |
99 | ||
100 | struct cfq_data { | |
101 | struct list_head rr_list; | |
102 | struct list_head empty_list; | |
103 | ||
104 | struct hlist_head *cfq_hash; | |
105 | struct hlist_head *crq_hash; | |
106 | ||
107 | /* queues on rr_list (ie they have pending requests */ | |
108 | unsigned int busy_queues; | |
109 | ||
110 | unsigned int max_queued; | |
111 | ||
112 | atomic_t ref; | |
113 | ||
114 | int key_type; | |
115 | ||
116 | mempool_t *crq_pool; | |
117 | ||
118 | request_queue_t *queue; | |
119 | ||
120 | sector_t last_sector; | |
121 | ||
122 | int rq_in_driver; | |
123 | ||
124 | /* | |
125 | * tunables, see top of file | |
126 | */ | |
127 | unsigned int cfq_quantum; | |
128 | unsigned int cfq_queued; | |
129 | unsigned int cfq_fifo_expire_r; | |
130 | unsigned int cfq_fifo_expire_w; | |
131 | unsigned int cfq_fifo_batch_expire; | |
132 | unsigned int cfq_back_penalty; | |
133 | unsigned int cfq_back_max; | |
134 | unsigned int find_best_crq; | |
135 | ||
136 | unsigned int cfq_tagged; | |
137 | }; | |
138 | ||
139 | struct cfq_queue { | |
140 | /* reference count */ | |
141 | atomic_t ref; | |
142 | /* parent cfq_data */ | |
143 | struct cfq_data *cfqd; | |
144 | /* hash of mergeable requests */ | |
145 | struct hlist_node cfq_hash; | |
146 | /* hash key */ | |
147 | unsigned long key; | |
148 | /* whether queue is on rr (or empty) list */ | |
149 | int on_rr; | |
150 | /* on either rr or empty list of cfqd */ | |
151 | struct list_head cfq_list; | |
152 | /* sorted list of pending requests */ | |
153 | struct rb_root sort_list; | |
154 | /* if fifo isn't expired, next request to serve */ | |
155 | struct cfq_rq *next_crq; | |
156 | /* requests queued in sort_list */ | |
157 | int queued[2]; | |
158 | /* currently allocated requests */ | |
159 | int allocated[2]; | |
160 | /* fifo list of requests in sort_list */ | |
161 | struct list_head fifo[2]; | |
162 | /* last time fifo expired */ | |
163 | unsigned long last_fifo_expire; | |
164 | ||
165 | int key_type; | |
166 | ||
167 | unsigned long service_start; | |
168 | unsigned long service_used; | |
169 | ||
170 | unsigned int max_rate; | |
171 | ||
172 | /* number of requests that have been handed to the driver */ | |
173 | int in_flight; | |
174 | /* number of currently allocated requests */ | |
175 | int alloc_limit[2]; | |
176 | }; | |
177 | ||
178 | struct cfq_rq { | |
179 | struct rb_node rb_node; | |
180 | sector_t rb_key; | |
181 | struct request *request; | |
182 | struct hlist_node hash; | |
183 | ||
184 | struct cfq_queue *cfq_queue; | |
185 | struct cfq_io_context *io_context; | |
186 | ||
187 | unsigned long service_start; | |
188 | unsigned long queue_start; | |
189 | ||
190 | unsigned int in_flight : 1; | |
191 | unsigned int accounted : 1; | |
192 | unsigned int is_sync : 1; | |
193 | unsigned int is_write : 1; | |
194 | }; | |
195 | ||
196 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned long); | |
197 | static void cfq_dispatch_sort(request_queue_t *, struct cfq_rq *); | |
198 | static void cfq_update_next_crq(struct cfq_rq *); | |
199 | static void cfq_put_cfqd(struct cfq_data *cfqd); | |
200 | ||
201 | /* | |
202 | * what the fairness is based on (ie how processes are grouped and | |
203 | * differentiated) | |
204 | */ | |
205 | static inline unsigned long | |
206 | cfq_hash_key(struct cfq_data *cfqd, struct task_struct *tsk) | |
207 | { | |
208 | /* | |
209 | * optimize this so that ->key_type is the offset into the struct | |
210 | */ | |
211 | switch (cfqd->key_type) { | |
212 | case CFQ_KEY_PGID: | |
213 | return process_group(tsk); | |
214 | default: | |
215 | case CFQ_KEY_TGID: | |
216 | return tsk->tgid; | |
217 | case CFQ_KEY_UID: | |
218 | return tsk->uid; | |
219 | case CFQ_KEY_GID: | |
220 | return tsk->gid; | |
221 | } | |
222 | } | |
223 | ||
224 | /* | |
225 | * lots of deadline iosched dupes, can be abstracted later... | |
226 | */ | |
227 | static inline void cfq_del_crq_hash(struct cfq_rq *crq) | |
228 | { | |
229 | hlist_del_init(&crq->hash); | |
230 | } | |
231 | ||
232 | static void cfq_remove_merge_hints(request_queue_t *q, struct cfq_rq *crq) | |
233 | { | |
234 | cfq_del_crq_hash(crq); | |
235 | ||
236 | if (q->last_merge == crq->request) | |
237 | q->last_merge = NULL; | |
238 | ||
239 | cfq_update_next_crq(crq); | |
240 | } | |
241 | ||
242 | static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) | |
243 | { | |
244 | const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); | |
245 | ||
246 | BUG_ON(!hlist_unhashed(&crq->hash)); | |
247 | ||
248 | hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); | |
249 | } | |
250 | ||
251 | static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) | |
252 | { | |
253 | struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)]; | |
254 | struct hlist_node *entry, *next; | |
255 | ||
256 | hlist_for_each_safe(entry, next, hash_list) { | |
257 | struct cfq_rq *crq = list_entry_hash(entry); | |
258 | struct request *__rq = crq->request; | |
259 | ||
260 | BUG_ON(hlist_unhashed(&crq->hash)); | |
261 | ||
262 | if (!rq_mergeable(__rq)) { | |
263 | cfq_del_crq_hash(crq); | |
264 | continue; | |
265 | } | |
266 | ||
267 | if (rq_hash_key(__rq) == offset) | |
268 | return __rq; | |
269 | } | |
270 | ||
271 | return NULL; | |
272 | } | |
273 | ||
274 | /* | |
275 | * Lifted from AS - choose which of crq1 and crq2 that is best served now. | |
276 | * We choose the request that is closest to the head right now. Distance | |
277 | * behind the head are penalized and only allowed to a certain extent. | |
278 | */ | |
279 | static struct cfq_rq * | |
280 | cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) | |
281 | { | |
282 | sector_t last, s1, s2, d1 = 0, d2 = 0; | |
283 | int r1_wrap = 0, r2_wrap = 0; /* requests are behind the disk head */ | |
284 | unsigned long back_max; | |
285 | ||
286 | if (crq1 == NULL || crq1 == crq2) | |
287 | return crq2; | |
288 | if (crq2 == NULL) | |
289 | return crq1; | |
290 | ||
291 | s1 = crq1->request->sector; | |
292 | s2 = crq2->request->sector; | |
293 | ||
294 | last = cfqd->last_sector; | |
295 | ||
296 | #if 0 | |
297 | if (!list_empty(&cfqd->queue->queue_head)) { | |
298 | struct list_head *entry = &cfqd->queue->queue_head; | |
299 | unsigned long distance = ~0UL; | |
300 | struct request *rq; | |
301 | ||
302 | while ((entry = entry->prev) != &cfqd->queue->queue_head) { | |
303 | rq = list_entry_rq(entry); | |
304 | ||
305 | if (blk_barrier_rq(rq)) | |
306 | break; | |
307 | ||
308 | if (distance < abs(s1 - rq->sector + rq->nr_sectors)) { | |
309 | distance = abs(s1 - rq->sector +rq->nr_sectors); | |
310 | last = rq->sector + rq->nr_sectors; | |
311 | } | |
312 | if (distance < abs(s2 - rq->sector + rq->nr_sectors)) { | |
313 | distance = abs(s2 - rq->sector +rq->nr_sectors); | |
314 | last = rq->sector + rq->nr_sectors; | |
315 | } | |
316 | } | |
317 | } | |
318 | #endif | |
319 | ||
320 | /* | |
321 | * by definition, 1KiB is 2 sectors | |
322 | */ | |
323 | back_max = cfqd->cfq_back_max * 2; | |
324 | ||
325 | /* | |
326 | * Strict one way elevator _except_ in the case where we allow | |
327 | * short backward seeks which are biased as twice the cost of a | |
328 | * similar forward seek. | |
329 | */ | |
330 | if (s1 >= last) | |
331 | d1 = s1 - last; | |
332 | else if (s1 + back_max >= last) | |
333 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
334 | else | |
335 | r1_wrap = 1; | |
336 | ||
337 | if (s2 >= last) | |
338 | d2 = s2 - last; | |
339 | else if (s2 + back_max >= last) | |
340 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
341 | else | |
342 | r2_wrap = 1; | |
343 | ||
344 | /* Found required data */ | |
345 | if (!r1_wrap && r2_wrap) | |
346 | return crq1; | |
347 | else if (!r2_wrap && r1_wrap) | |
348 | return crq2; | |
349 | else if (r1_wrap && r2_wrap) { | |
350 | /* both behind the head */ | |
351 | if (s1 <= s2) | |
352 | return crq1; | |
353 | else | |
354 | return crq2; | |
355 | } | |
356 | ||
357 | /* Both requests in front of the head */ | |
358 | if (d1 < d2) | |
359 | return crq1; | |
360 | else if (d2 < d1) | |
361 | return crq2; | |
362 | else { | |
363 | if (s1 >= s2) | |
364 | return crq1; | |
365 | else | |
366 | return crq2; | |
367 | } | |
368 | } | |
369 | ||
370 | /* | |
371 | * would be nice to take fifo expire time into account as well | |
372 | */ | |
373 | static struct cfq_rq * | |
374 | cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
375 | struct cfq_rq *last) | |
376 | { | |
377 | struct cfq_rq *crq_next = NULL, *crq_prev = NULL; | |
378 | struct rb_node *rbnext, *rbprev; | |
379 | ||
380 | if (!ON_RB(&last->rb_node)) | |
381 | return NULL; | |
382 | ||
383 | if ((rbnext = rb_next(&last->rb_node)) == NULL) | |
384 | rbnext = rb_first(&cfqq->sort_list); | |
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 | ||
404 | static int cfq_check_sort_rr_list(struct cfq_queue *cfqq) | |
405 | { | |
406 | struct list_head *head = &cfqq->cfqd->rr_list; | |
407 | struct list_head *next, *prev; | |
408 | ||
409 | /* | |
410 | * list might still be ordered | |
411 | */ | |
412 | next = cfqq->cfq_list.next; | |
413 | if (next != head) { | |
414 | struct cfq_queue *cnext = list_entry_cfqq(next); | |
415 | ||
416 | if (cfqq->service_used > cnext->service_used) | |
417 | return 1; | |
418 | } | |
419 | ||
420 | prev = cfqq->cfq_list.prev; | |
421 | if (prev != head) { | |
422 | struct cfq_queue *cprev = list_entry_cfqq(prev); | |
423 | ||
424 | if (cfqq->service_used < cprev->service_used) | |
425 | return 1; | |
426 | } | |
427 | ||
428 | return 0; | |
429 | } | |
430 | ||
431 | static void cfq_sort_rr_list(struct cfq_queue *cfqq, int new_queue) | |
432 | { | |
433 | struct list_head *entry = &cfqq->cfqd->rr_list; | |
434 | ||
435 | if (!cfqq->on_rr) | |
436 | return; | |
437 | if (!new_queue && !cfq_check_sort_rr_list(cfqq)) | |
438 | return; | |
439 | ||
440 | list_del(&cfqq->cfq_list); | |
441 | ||
442 | /* | |
443 | * sort by our mean service_used, sub-sort by in-flight requests | |
444 | */ | |
445 | while ((entry = entry->prev) != &cfqq->cfqd->rr_list) { | |
446 | struct cfq_queue *__cfqq = list_entry_cfqq(entry); | |
447 | ||
448 | if (cfqq->service_used > __cfqq->service_used) | |
449 | break; | |
450 | else if (cfqq->service_used == __cfqq->service_used) { | |
451 | struct list_head *prv; | |
452 | ||
453 | while ((prv = entry->prev) != &cfqq->cfqd->rr_list) { | |
454 | __cfqq = list_entry_cfqq(prv); | |
455 | ||
456 | WARN_ON(__cfqq->service_used > cfqq->service_used); | |
457 | if (cfqq->service_used != __cfqq->service_used) | |
458 | break; | |
459 | if (cfqq->in_flight > __cfqq->in_flight) | |
460 | break; | |
461 | ||
462 | entry = prv; | |
463 | } | |
464 | } | |
465 | } | |
466 | ||
467 | list_add(&cfqq->cfq_list, entry); | |
468 | } | |
469 | ||
470 | /* | |
471 | * add to busy list of queues for service, trying to be fair in ordering | |
472 | * the pending list according to requests serviced | |
473 | */ | |
474 | static inline void | |
475 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
476 | { | |
477 | /* | |
478 | * it's currently on the empty list | |
479 | */ | |
480 | cfqq->on_rr = 1; | |
481 | cfqd->busy_queues++; | |
482 | ||
483 | if (time_after(jiffies, cfqq->service_start + cfq_service)) | |
484 | cfqq->service_used >>= 3; | |
485 | ||
486 | cfq_sort_rr_list(cfqq, 1); | |
487 | } | |
488 | ||
489 | static inline void | |
490 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
491 | { | |
492 | list_move(&cfqq->cfq_list, &cfqd->empty_list); | |
493 | cfqq->on_rr = 0; | |
494 | ||
495 | BUG_ON(!cfqd->busy_queues); | |
496 | cfqd->busy_queues--; | |
497 | } | |
498 | ||
499 | /* | |
500 | * rb tree support functions | |
501 | */ | |
502 | static inline void cfq_del_crq_rb(struct cfq_rq *crq) | |
503 | { | |
504 | struct cfq_queue *cfqq = crq->cfq_queue; | |
505 | ||
506 | if (ON_RB(&crq->rb_node)) { | |
507 | struct cfq_data *cfqd = cfqq->cfqd; | |
508 | ||
509 | BUG_ON(!cfqq->queued[crq->is_sync]); | |
510 | ||
511 | cfq_update_next_crq(crq); | |
512 | ||
513 | cfqq->queued[crq->is_sync]--; | |
514 | rb_erase(&crq->rb_node, &cfqq->sort_list); | |
515 | RB_CLEAR_COLOR(&crq->rb_node); | |
516 | ||
517 | if (RB_EMPTY(&cfqq->sort_list) && cfqq->on_rr) | |
518 | cfq_del_cfqq_rr(cfqd, cfqq); | |
519 | } | |
520 | } | |
521 | ||
522 | static struct cfq_rq * | |
523 | __cfq_add_crq_rb(struct cfq_rq *crq) | |
524 | { | |
525 | struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; | |
526 | struct rb_node *parent = NULL; | |
527 | struct cfq_rq *__crq; | |
528 | ||
529 | while (*p) { | |
530 | parent = *p; | |
531 | __crq = rb_entry_crq(parent); | |
532 | ||
533 | if (crq->rb_key < __crq->rb_key) | |
534 | p = &(*p)->rb_left; | |
535 | else if (crq->rb_key > __crq->rb_key) | |
536 | p = &(*p)->rb_right; | |
537 | else | |
538 | return __crq; | |
539 | } | |
540 | ||
541 | rb_link_node(&crq->rb_node, parent, p); | |
542 | return NULL; | |
543 | } | |
544 | ||
545 | static void cfq_add_crq_rb(struct cfq_rq *crq) | |
546 | { | |
547 | struct cfq_queue *cfqq = crq->cfq_queue; | |
548 | struct cfq_data *cfqd = cfqq->cfqd; | |
549 | struct request *rq = crq->request; | |
550 | struct cfq_rq *__alias; | |
551 | ||
552 | crq->rb_key = rq_rb_key(rq); | |
553 | cfqq->queued[crq->is_sync]++; | |
554 | ||
555 | /* | |
556 | * looks a little odd, but the first insert might return an alias. | |
557 | * if that happens, put the alias on the dispatch list | |
558 | */ | |
559 | while ((__alias = __cfq_add_crq_rb(crq)) != NULL) | |
560 | cfq_dispatch_sort(cfqd->queue, __alias); | |
561 | ||
562 | rb_insert_color(&crq->rb_node, &cfqq->sort_list); | |
563 | ||
564 | if (!cfqq->on_rr) | |
565 | cfq_add_cfqq_rr(cfqd, cfqq); | |
566 | ||
567 | /* | |
568 | * check if this request is a better next-serve candidate | |
569 | */ | |
570 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
571 | } | |
572 | ||
573 | static inline void | |
574 | cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) | |
575 | { | |
576 | if (ON_RB(&crq->rb_node)) { | |
577 | rb_erase(&crq->rb_node, &cfqq->sort_list); | |
578 | cfqq->queued[crq->is_sync]--; | |
579 | } | |
580 | ||
581 | cfq_add_crq_rb(crq); | |
582 | } | |
583 | ||
584 | static struct request * | |
585 | cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) | |
586 | { | |
587 | const unsigned long key = cfq_hash_key(cfqd, current); | |
588 | struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, key); | |
589 | struct rb_node *n; | |
590 | ||
591 | if (!cfqq) | |
592 | goto out; | |
593 | ||
594 | n = cfqq->sort_list.rb_node; | |
595 | while (n) { | |
596 | struct cfq_rq *crq = rb_entry_crq(n); | |
597 | ||
598 | if (sector < crq->rb_key) | |
599 | n = n->rb_left; | |
600 | else if (sector > crq->rb_key) | |
601 | n = n->rb_right; | |
602 | else | |
603 | return crq->request; | |
604 | } | |
605 | ||
606 | out: | |
607 | return NULL; | |
608 | } | |
609 | ||
610 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) | |
611 | { | |
612 | struct cfq_rq *crq = RQ_DATA(rq); | |
613 | ||
614 | if (crq) { | |
615 | struct cfq_queue *cfqq = crq->cfq_queue; | |
616 | ||
617 | if (cfqq->cfqd->cfq_tagged) { | |
618 | cfqq->service_used--; | |
619 | cfq_sort_rr_list(cfqq, 0); | |
620 | } | |
621 | ||
622 | if (crq->accounted) { | |
623 | crq->accounted = 0; | |
624 | cfqq->cfqd->rq_in_driver--; | |
625 | } | |
626 | } | |
627 | } | |
628 | ||
629 | /* | |
630 | * make sure the service time gets corrected on reissue of this request | |
631 | */ | |
632 | static void cfq_requeue_request(request_queue_t *q, struct request *rq) | |
633 | { | |
634 | cfq_deactivate_request(q, rq); | |
635 | list_add(&rq->queuelist, &q->queue_head); | |
636 | } | |
637 | ||
638 | static void cfq_remove_request(request_queue_t *q, struct request *rq) | |
639 | { | |
640 | struct cfq_rq *crq = RQ_DATA(rq); | |
641 | ||
642 | if (crq) { | |
643 | cfq_remove_merge_hints(q, crq); | |
644 | list_del_init(&rq->queuelist); | |
645 | ||
646 | if (crq->cfq_queue) | |
647 | cfq_del_crq_rb(crq); | |
648 | } | |
649 | } | |
650 | ||
651 | static int | |
652 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
653 | { | |
654 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
655 | struct request *__rq; | |
656 | int ret; | |
657 | ||
658 | ret = elv_try_last_merge(q, bio); | |
659 | if (ret != ELEVATOR_NO_MERGE) { | |
660 | __rq = q->last_merge; | |
661 | goto out_insert; | |
662 | } | |
663 | ||
664 | __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); | |
665 | if (__rq) { | |
666 | BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector); | |
667 | ||
668 | if (elv_rq_merge_ok(__rq, bio)) { | |
669 | ret = ELEVATOR_BACK_MERGE; | |
670 | goto out; | |
671 | } | |
672 | } | |
673 | ||
674 | __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); | |
675 | if (__rq) { | |
676 | if (elv_rq_merge_ok(__rq, bio)) { | |
677 | ret = ELEVATOR_FRONT_MERGE; | |
678 | goto out; | |
679 | } | |
680 | } | |
681 | ||
682 | return ELEVATOR_NO_MERGE; | |
683 | out: | |
684 | q->last_merge = __rq; | |
685 | out_insert: | |
686 | *req = __rq; | |
687 | return ret; | |
688 | } | |
689 | ||
690 | static void cfq_merged_request(request_queue_t *q, struct request *req) | |
691 | { | |
692 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
693 | struct cfq_rq *crq = RQ_DATA(req); | |
694 | ||
695 | cfq_del_crq_hash(crq); | |
696 | cfq_add_crq_hash(cfqd, crq); | |
697 | ||
698 | if (ON_RB(&crq->rb_node) && (rq_rb_key(req) != crq->rb_key)) { | |
699 | struct cfq_queue *cfqq = crq->cfq_queue; | |
700 | ||
701 | cfq_update_next_crq(crq); | |
702 | cfq_reposition_crq_rb(cfqq, crq); | |
703 | } | |
704 | ||
705 | q->last_merge = req; | |
706 | } | |
707 | ||
708 | static void | |
709 | cfq_merged_requests(request_queue_t *q, struct request *rq, | |
710 | struct request *next) | |
711 | { | |
712 | struct cfq_rq *crq = RQ_DATA(rq); | |
713 | struct cfq_rq *cnext = RQ_DATA(next); | |
714 | ||
715 | cfq_merged_request(q, rq); | |
716 | ||
717 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist)) { | |
718 | if (time_before(cnext->queue_start, crq->queue_start)) { | |
719 | list_move(&rq->queuelist, &next->queuelist); | |
720 | crq->queue_start = cnext->queue_start; | |
721 | } | |
722 | } | |
723 | ||
724 | cfq_update_next_crq(cnext); | |
725 | cfq_remove_request(q, next); | |
726 | } | |
727 | ||
728 | /* | |
729 | * we dispatch cfqd->cfq_quantum requests in total from the rr_list queues, | |
730 | * this function sector sorts the selected request to minimize seeks. we start | |
731 | * at cfqd->last_sector, not 0. | |
732 | */ | |
733 | static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq) | |
734 | { | |
735 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
736 | struct cfq_queue *cfqq = crq->cfq_queue; | |
737 | struct list_head *head = &q->queue_head, *entry = head; | |
738 | struct request *__rq; | |
739 | sector_t last; | |
740 | ||
741 | cfq_del_crq_rb(crq); | |
742 | cfq_remove_merge_hints(q, crq); | |
743 | list_del(&crq->request->queuelist); | |
744 | ||
745 | last = cfqd->last_sector; | |
746 | while ((entry = entry->prev) != head) { | |
747 | __rq = list_entry_rq(entry); | |
748 | ||
749 | if (blk_barrier_rq(crq->request)) | |
750 | break; | |
751 | if (!blk_fs_request(crq->request)) | |
752 | break; | |
753 | ||
754 | if (crq->request->sector > __rq->sector) | |
755 | break; | |
756 | if (__rq->sector > last && crq->request->sector < last) { | |
757 | last = crq->request->sector; | |
758 | break; | |
759 | } | |
760 | } | |
761 | ||
762 | cfqd->last_sector = last; | |
763 | crq->in_flight = 1; | |
764 | cfqq->in_flight++; | |
765 | list_add(&crq->request->queuelist, entry); | |
766 | } | |
767 | ||
768 | /* | |
769 | * return expired entry, or NULL to just start from scratch in rbtree | |
770 | */ | |
771 | static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) | |
772 | { | |
773 | struct cfq_data *cfqd = cfqq->cfqd; | |
774 | const int reads = !list_empty(&cfqq->fifo[0]); | |
775 | const int writes = !list_empty(&cfqq->fifo[1]); | |
776 | unsigned long now = jiffies; | |
777 | struct cfq_rq *crq; | |
778 | ||
779 | if (time_before(now, cfqq->last_fifo_expire + cfqd->cfq_fifo_batch_expire)) | |
780 | return NULL; | |
781 | ||
782 | crq = RQ_DATA(list_entry(cfqq->fifo[0].next, struct request, queuelist)); | |
783 | if (reads && time_after(now, crq->queue_start + cfqd->cfq_fifo_expire_r)) { | |
784 | cfqq->last_fifo_expire = now; | |
785 | return crq; | |
786 | } | |
787 | ||
788 | crq = RQ_DATA(list_entry(cfqq->fifo[1].next, struct request, queuelist)); | |
789 | if (writes && time_after(now, crq->queue_start + cfqd->cfq_fifo_expire_w)) { | |
790 | cfqq->last_fifo_expire = now; | |
791 | return crq; | |
792 | } | |
793 | ||
794 | return NULL; | |
795 | } | |
796 | ||
797 | /* | |
798 | * dispatch a single request from given queue | |
799 | */ | |
800 | static inline void | |
801 | cfq_dispatch_request(request_queue_t *q, struct cfq_data *cfqd, | |
802 | struct cfq_queue *cfqq) | |
803 | { | |
804 | struct cfq_rq *crq; | |
805 | ||
806 | /* | |
807 | * follow expired path, else get first next available | |
808 | */ | |
809 | if ((crq = cfq_check_fifo(cfqq)) == NULL) { | |
810 | if (cfqd->find_best_crq) | |
811 | crq = cfqq->next_crq; | |
812 | else | |
813 | crq = rb_entry_crq(rb_first(&cfqq->sort_list)); | |
814 | } | |
815 | ||
816 | cfqd->last_sector = crq->request->sector + crq->request->nr_sectors; | |
817 | ||
818 | /* | |
819 | * finally, insert request into driver list | |
820 | */ | |
821 | cfq_dispatch_sort(q, crq); | |
822 | } | |
823 | ||
824 | static int cfq_dispatch_requests(request_queue_t *q, int max_dispatch) | |
825 | { | |
826 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
827 | struct cfq_queue *cfqq; | |
828 | struct list_head *entry, *tmp; | |
829 | int queued, busy_queues, first_round; | |
830 | ||
831 | if (list_empty(&cfqd->rr_list)) | |
832 | return 0; | |
833 | ||
834 | queued = 0; | |
835 | first_round = 1; | |
836 | restart: | |
837 | busy_queues = 0; | |
838 | list_for_each_safe(entry, tmp, &cfqd->rr_list) { | |
839 | cfqq = list_entry_cfqq(entry); | |
840 | ||
841 | BUG_ON(RB_EMPTY(&cfqq->sort_list)); | |
842 | ||
843 | /* | |
844 | * first round of queueing, only select from queues that | |
845 | * don't already have io in-flight | |
846 | */ | |
847 | if (first_round && cfqq->in_flight) | |
848 | continue; | |
849 | ||
850 | cfq_dispatch_request(q, cfqd, cfqq); | |
851 | ||
852 | if (!RB_EMPTY(&cfqq->sort_list)) | |
853 | busy_queues++; | |
854 | ||
855 | queued++; | |
856 | } | |
857 | ||
858 | if ((queued < max_dispatch) && (busy_queues || first_round)) { | |
859 | first_round = 0; | |
860 | goto restart; | |
861 | } | |
862 | ||
863 | return queued; | |
864 | } | |
865 | ||
866 | static inline void cfq_account_dispatch(struct cfq_rq *crq) | |
867 | { | |
868 | struct cfq_queue *cfqq = crq->cfq_queue; | |
869 | struct cfq_data *cfqd = cfqq->cfqd; | |
870 | unsigned long now, elapsed; | |
871 | ||
872 | if (!blk_fs_request(crq->request)) | |
873 | return; | |
874 | ||
875 | /* | |
876 | * accounted bit is necessary since some drivers will call | |
877 | * elv_next_request() many times for the same request (eg ide) | |
878 | */ | |
879 | if (crq->accounted) | |
880 | return; | |
881 | ||
882 | now = jiffies; | |
883 | if (cfqq->service_start == ~0UL) | |
884 | cfqq->service_start = now; | |
885 | ||
886 | /* | |
887 | * on drives with tagged command queueing, command turn-around time | |
888 | * doesn't necessarily reflect the time spent processing this very | |
889 | * command inside the drive. so do the accounting differently there, | |
890 | * by just sorting on the number of requests | |
891 | */ | |
892 | if (cfqd->cfq_tagged) { | |
893 | if (time_after(now, cfqq->service_start + cfq_service)) { | |
894 | cfqq->service_start = now; | |
895 | cfqq->service_used /= 10; | |
896 | } | |
897 | ||
898 | cfqq->service_used++; | |
899 | cfq_sort_rr_list(cfqq, 0); | |
900 | } | |
901 | ||
902 | elapsed = now - crq->queue_start; | |
903 | if (elapsed > max_elapsed_dispatch) | |
904 | max_elapsed_dispatch = elapsed; | |
905 | ||
906 | crq->accounted = 1; | |
907 | crq->service_start = now; | |
908 | ||
909 | if (++cfqd->rq_in_driver >= CFQ_MAX_TAG && !cfqd->cfq_tagged) { | |
910 | cfqq->cfqd->cfq_tagged = 1; | |
911 | printk("cfq: depth %d reached, tagging now on\n", CFQ_MAX_TAG); | |
912 | } | |
913 | } | |
914 | ||
915 | static inline void | |
916 | cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq) | |
917 | { | |
918 | struct cfq_data *cfqd = cfqq->cfqd; | |
919 | ||
920 | if (!crq->accounted) | |
921 | return; | |
922 | ||
923 | WARN_ON(!cfqd->rq_in_driver); | |
924 | cfqd->rq_in_driver--; | |
925 | ||
926 | if (!cfqd->cfq_tagged) { | |
927 | unsigned long now = jiffies; | |
928 | unsigned long duration = now - crq->service_start; | |
929 | ||
930 | if (time_after(now, cfqq->service_start + cfq_service)) { | |
931 | cfqq->service_start = now; | |
932 | cfqq->service_used >>= 3; | |
933 | } | |
934 | ||
935 | cfqq->service_used += duration; | |
936 | cfq_sort_rr_list(cfqq, 0); | |
937 | ||
938 | if (duration > max_elapsed_crq) | |
939 | max_elapsed_crq = duration; | |
940 | } | |
941 | } | |
942 | ||
943 | static struct request *cfq_next_request(request_queue_t *q) | |
944 | { | |
945 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
946 | struct request *rq; | |
947 | ||
948 | if (!list_empty(&q->queue_head)) { | |
949 | struct cfq_rq *crq; | |
950 | dispatch: | |
951 | rq = list_entry_rq(q->queue_head.next); | |
952 | ||
953 | if ((crq = RQ_DATA(rq)) != NULL) { | |
954 | cfq_remove_merge_hints(q, crq); | |
955 | cfq_account_dispatch(crq); | |
956 | } | |
957 | ||
958 | return rq; | |
959 | } | |
960 | ||
961 | if (cfq_dispatch_requests(q, cfqd->cfq_quantum)) | |
962 | goto dispatch; | |
963 | ||
964 | return NULL; | |
965 | } | |
966 | ||
967 | /* | |
968 | * task holds one reference to the queue, dropped when task exits. each crq | |
969 | * in-flight on this queue also holds a reference, dropped when crq is freed. | |
970 | * | |
971 | * queue lock must be held here. | |
972 | */ | |
973 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
974 | { | |
975 | BUG_ON(!atomic_read(&cfqq->ref)); | |
976 | ||
977 | if (!atomic_dec_and_test(&cfqq->ref)) | |
978 | return; | |
979 | ||
980 | BUG_ON(rb_first(&cfqq->sort_list)); | |
981 | BUG_ON(cfqq->on_rr); | |
982 | ||
983 | cfq_put_cfqd(cfqq->cfqd); | |
984 | ||
985 | /* | |
986 | * it's on the empty list and still hashed | |
987 | */ | |
988 | list_del(&cfqq->cfq_list); | |
989 | hlist_del(&cfqq->cfq_hash); | |
990 | kmem_cache_free(cfq_pool, cfqq); | |
991 | } | |
992 | ||
993 | static inline struct cfq_queue * | |
994 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned long key, const int hashval) | |
995 | { | |
996 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; | |
997 | struct hlist_node *entry, *next; | |
998 | ||
999 | hlist_for_each_safe(entry, next, hash_list) { | |
1000 | struct cfq_queue *__cfqq = list_entry_qhash(entry); | |
1001 | ||
1002 | if (__cfqq->key == key) | |
1003 | return __cfqq; | |
1004 | } | |
1005 | ||
1006 | return NULL; | |
1007 | } | |
1008 | ||
1009 | static struct cfq_queue * | |
1010 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned long key) | |
1011 | { | |
1012 | return __cfq_find_cfq_hash(cfqd, key, hash_long(key, CFQ_QHASH_SHIFT)); | |
1013 | } | |
1014 | ||
1015 | static inline void | |
1016 | cfq_rehash_cfqq(struct cfq_data *cfqd, struct cfq_queue **cfqq, | |
1017 | struct cfq_io_context *cic) | |
1018 | { | |
1019 | unsigned long hashkey = cfq_hash_key(cfqd, current); | |
1020 | unsigned long hashval = hash_long(hashkey, CFQ_QHASH_SHIFT); | |
1021 | struct cfq_queue *__cfqq; | |
1022 | unsigned long flags; | |
1023 | ||
1024 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1025 | ||
1026 | hlist_del(&(*cfqq)->cfq_hash); | |
1027 | ||
1028 | __cfqq = __cfq_find_cfq_hash(cfqd, hashkey, hashval); | |
1029 | if (!__cfqq || __cfqq == *cfqq) { | |
1030 | __cfqq = *cfqq; | |
1031 | hlist_add_head(&__cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); | |
1032 | __cfqq->key_type = cfqd->key_type; | |
1033 | } else { | |
1034 | atomic_inc(&__cfqq->ref); | |
1035 | cic->cfqq = __cfqq; | |
1036 | cfq_put_queue(*cfqq); | |
1037 | *cfqq = __cfqq; | |
1038 | } | |
1039 | ||
1040 | cic->cfqq = __cfqq; | |
1041 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1042 | } | |
1043 | ||
1044 | static void cfq_free_io_context(struct cfq_io_context *cic) | |
1045 | { | |
1046 | kmem_cache_free(cfq_ioc_pool, cic); | |
1047 | } | |
1048 | ||
1049 | /* | |
1050 | * locking hierarchy is: io_context lock -> queue locks | |
1051 | */ | |
1052 | static void cfq_exit_io_context(struct cfq_io_context *cic) | |
1053 | { | |
1054 | struct cfq_queue *cfqq = cic->cfqq; | |
1055 | struct list_head *entry = &cic->list; | |
1056 | request_queue_t *q; | |
1057 | unsigned long flags; | |
1058 | ||
1059 | /* | |
1060 | * put the reference this task is holding to the various queues | |
1061 | */ | |
1062 | spin_lock_irqsave(&cic->ioc->lock, flags); | |
1063 | while ((entry = cic->list.next) != &cic->list) { | |
1064 | struct cfq_io_context *__cic; | |
1065 | ||
1066 | __cic = list_entry(entry, struct cfq_io_context, list); | |
1067 | list_del(entry); | |
1068 | ||
1069 | q = __cic->cfqq->cfqd->queue; | |
1070 | spin_lock(q->queue_lock); | |
1071 | cfq_put_queue(__cic->cfqq); | |
1072 | spin_unlock(q->queue_lock); | |
1073 | } | |
1074 | ||
1075 | q = cfqq->cfqd->queue; | |
1076 | spin_lock(q->queue_lock); | |
1077 | cfq_put_queue(cfqq); | |
1078 | spin_unlock(q->queue_lock); | |
1079 | ||
1080 | cic->cfqq = NULL; | |
1081 | spin_unlock_irqrestore(&cic->ioc->lock, flags); | |
1082 | } | |
1083 | ||
1084 | static struct cfq_io_context *cfq_alloc_io_context(int gfp_flags) | |
1085 | { | |
1086 | struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_flags); | |
1087 | ||
1088 | if (cic) { | |
1089 | cic->dtor = cfq_free_io_context; | |
1090 | cic->exit = cfq_exit_io_context; | |
1091 | INIT_LIST_HEAD(&cic->list); | |
1092 | cic->cfqq = NULL; | |
1093 | } | |
1094 | ||
1095 | return cic; | |
1096 | } | |
1097 | ||
1098 | /* | |
1099 | * Setup general io context and cfq io context. There can be several cfq | |
1100 | * io contexts per general io context, if this process is doing io to more | |
1101 | * than one device managed by cfq. Note that caller is holding a reference to | |
1102 | * cfqq, so we don't need to worry about it disappearing | |
1103 | */ | |
1104 | static struct cfq_io_context * | |
1105 | cfq_get_io_context(struct cfq_queue **cfqq, int gfp_flags) | |
1106 | { | |
1107 | struct cfq_data *cfqd = (*cfqq)->cfqd; | |
1108 | struct cfq_queue *__cfqq = *cfqq; | |
1109 | struct cfq_io_context *cic; | |
1110 | struct io_context *ioc; | |
1111 | ||
1112 | might_sleep_if(gfp_flags & __GFP_WAIT); | |
1113 | ||
1114 | ioc = get_io_context(gfp_flags); | |
1115 | if (!ioc) | |
1116 | return NULL; | |
1117 | ||
1118 | if ((cic = ioc->cic) == NULL) { | |
1119 | cic = cfq_alloc_io_context(gfp_flags); | |
1120 | ||
1121 | if (cic == NULL) | |
1122 | goto err; | |
1123 | ||
1124 | ioc->cic = cic; | |
1125 | cic->ioc = ioc; | |
1126 | cic->cfqq = __cfqq; | |
1127 | atomic_inc(&__cfqq->ref); | |
1128 | } else { | |
1129 | struct cfq_io_context *__cic; | |
1130 | unsigned long flags; | |
1131 | ||
1132 | /* | |
1133 | * since the first cic on the list is actually the head | |
1134 | * itself, need to check this here or we'll duplicate an | |
1135 | * cic per ioc for no reason | |
1136 | */ | |
1137 | if (cic->cfqq == __cfqq) | |
1138 | goto out; | |
1139 | ||
1140 | /* | |
1141 | * cic exists, check if we already are there. linear search | |
1142 | * should be ok here, the list will usually not be more than | |
1143 | * 1 or a few entries long | |
1144 | */ | |
1145 | spin_lock_irqsave(&ioc->lock, flags); | |
1146 | list_for_each_entry(__cic, &cic->list, list) { | |
1147 | /* | |
1148 | * this process is already holding a reference to | |
1149 | * this queue, so no need to get one more | |
1150 | */ | |
1151 | if (__cic->cfqq == __cfqq) { | |
1152 | cic = __cic; | |
1153 | spin_unlock_irqrestore(&ioc->lock, flags); | |
1154 | goto out; | |
1155 | } | |
1156 | } | |
1157 | spin_unlock_irqrestore(&ioc->lock, flags); | |
1158 | ||
1159 | /* | |
1160 | * nope, process doesn't have a cic assoicated with this | |
1161 | * cfqq yet. get a new one and add to list | |
1162 | */ | |
1163 | __cic = cfq_alloc_io_context(gfp_flags); | |
1164 | if (__cic == NULL) | |
1165 | goto err; | |
1166 | ||
1167 | __cic->ioc = ioc; | |
1168 | __cic->cfqq = __cfqq; | |
1169 | atomic_inc(&__cfqq->ref); | |
1170 | spin_lock_irqsave(&ioc->lock, flags); | |
1171 | list_add(&__cic->list, &cic->list); | |
1172 | spin_unlock_irqrestore(&ioc->lock, flags); | |
1173 | ||
1174 | cic = __cic; | |
1175 | *cfqq = __cfqq; | |
1176 | } | |
1177 | ||
1178 | out: | |
1179 | /* | |
1180 | * if key_type has been changed on the fly, we lazily rehash | |
1181 | * each queue at lookup time | |
1182 | */ | |
1183 | if ((*cfqq)->key_type != cfqd->key_type) | |
1184 | cfq_rehash_cfqq(cfqd, cfqq, cic); | |
1185 | ||
1186 | return cic; | |
1187 | err: | |
1188 | put_io_context(ioc); | |
1189 | return NULL; | |
1190 | } | |
1191 | ||
1192 | static struct cfq_queue * | |
1193 | __cfq_get_queue(struct cfq_data *cfqd, unsigned long key, int gfp_mask) | |
1194 | { | |
1195 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); | |
1196 | struct cfq_queue *cfqq, *new_cfqq = NULL; | |
1197 | ||
1198 | retry: | |
1199 | cfqq = __cfq_find_cfq_hash(cfqd, key, hashval); | |
1200 | ||
1201 | if (!cfqq) { | |
1202 | if (new_cfqq) { | |
1203 | cfqq = new_cfqq; | |
1204 | new_cfqq = NULL; | |
1205 | } else if (gfp_mask & __GFP_WAIT) { | |
1206 | spin_unlock_irq(cfqd->queue->queue_lock); | |
1207 | new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1208 | spin_lock_irq(cfqd->queue->queue_lock); | |
1209 | goto retry; | |
1210 | } else | |
1211 | goto out; | |
1212 | ||
1213 | memset(cfqq, 0, sizeof(*cfqq)); | |
1214 | ||
1215 | INIT_HLIST_NODE(&cfqq->cfq_hash); | |
1216 | INIT_LIST_HEAD(&cfqq->cfq_list); | |
1217 | RB_CLEAR_ROOT(&cfqq->sort_list); | |
1218 | INIT_LIST_HEAD(&cfqq->fifo[0]); | |
1219 | INIT_LIST_HEAD(&cfqq->fifo[1]); | |
1220 | ||
1221 | cfqq->key = key; | |
1222 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); | |
1223 | atomic_set(&cfqq->ref, 0); | |
1224 | cfqq->cfqd = cfqd; | |
1225 | atomic_inc(&cfqd->ref); | |
1226 | cfqq->key_type = cfqd->key_type; | |
1227 | cfqq->service_start = ~0UL; | |
1228 | } | |
1229 | ||
1230 | if (new_cfqq) | |
1231 | kmem_cache_free(cfq_pool, new_cfqq); | |
1232 | ||
1233 | atomic_inc(&cfqq->ref); | |
1234 | out: | |
1235 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); | |
1236 | return cfqq; | |
1237 | } | |
1238 | ||
1239 | static void cfq_enqueue(struct cfq_data *cfqd, struct cfq_rq *crq) | |
1240 | { | |
1241 | crq->is_sync = 0; | |
1242 | if (rq_data_dir(crq->request) == READ || current->flags & PF_SYNCWRITE) | |
1243 | crq->is_sync = 1; | |
1244 | ||
1245 | cfq_add_crq_rb(crq); | |
1246 | crq->queue_start = jiffies; | |
1247 | ||
1248 | list_add_tail(&crq->request->queuelist, &crq->cfq_queue->fifo[crq->is_sync]); | |
1249 | } | |
1250 | ||
1251 | static void | |
1252 | cfq_insert_request(request_queue_t *q, struct request *rq, int where) | |
1253 | { | |
1254 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1255 | struct cfq_rq *crq = RQ_DATA(rq); | |
1256 | ||
1257 | switch (where) { | |
1258 | case ELEVATOR_INSERT_BACK: | |
1259 | while (cfq_dispatch_requests(q, cfqd->cfq_quantum)) | |
1260 | ; | |
1261 | list_add_tail(&rq->queuelist, &q->queue_head); | |
1262 | break; | |
1263 | case ELEVATOR_INSERT_FRONT: | |
1264 | list_add(&rq->queuelist, &q->queue_head); | |
1265 | break; | |
1266 | case ELEVATOR_INSERT_SORT: | |
1267 | BUG_ON(!blk_fs_request(rq)); | |
1268 | cfq_enqueue(cfqd, crq); | |
1269 | break; | |
1270 | default: | |
1271 | printk("%s: bad insert point %d\n", __FUNCTION__,where); | |
1272 | return; | |
1273 | } | |
1274 | ||
1275 | if (rq_mergeable(rq)) { | |
1276 | cfq_add_crq_hash(cfqd, crq); | |
1277 | ||
1278 | if (!q->last_merge) | |
1279 | q->last_merge = rq; | |
1280 | } | |
1281 | } | |
1282 | ||
1283 | static int cfq_queue_empty(request_queue_t *q) | |
1284 | { | |
1285 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1286 | ||
1287 | return list_empty(&q->queue_head) && list_empty(&cfqd->rr_list); | |
1288 | } | |
1289 | ||
1290 | static void cfq_completed_request(request_queue_t *q, struct request *rq) | |
1291 | { | |
1292 | struct cfq_rq *crq = RQ_DATA(rq); | |
1293 | struct cfq_queue *cfqq; | |
1294 | ||
1295 | if (unlikely(!blk_fs_request(rq))) | |
1296 | return; | |
1297 | ||
1298 | cfqq = crq->cfq_queue; | |
1299 | ||
1300 | if (crq->in_flight) { | |
1301 | WARN_ON(!cfqq->in_flight); | |
1302 | cfqq->in_flight--; | |
1303 | } | |
1304 | ||
1305 | cfq_account_completion(cfqq, crq); | |
1306 | } | |
1307 | ||
1308 | static struct request * | |
1309 | cfq_former_request(request_queue_t *q, struct request *rq) | |
1310 | { | |
1311 | struct cfq_rq *crq = RQ_DATA(rq); | |
1312 | struct rb_node *rbprev = rb_prev(&crq->rb_node); | |
1313 | ||
1314 | if (rbprev) | |
1315 | return rb_entry_crq(rbprev)->request; | |
1316 | ||
1317 | return NULL; | |
1318 | } | |
1319 | ||
1320 | static struct request * | |
1321 | cfq_latter_request(request_queue_t *q, struct request *rq) | |
1322 | { | |
1323 | struct cfq_rq *crq = RQ_DATA(rq); | |
1324 | struct rb_node *rbnext = rb_next(&crq->rb_node); | |
1325 | ||
1326 | if (rbnext) | |
1327 | return rb_entry_crq(rbnext)->request; | |
1328 | ||
1329 | return NULL; | |
1330 | } | |
1331 | ||
1332 | static int cfq_may_queue(request_queue_t *q, int rw) | |
1333 | { | |
1334 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1335 | struct cfq_queue *cfqq; | |
1336 | int ret = ELV_MQUEUE_MAY; | |
1337 | ||
1338 | if (current->flags & PF_MEMALLOC) | |
1339 | return ELV_MQUEUE_MAY; | |
1340 | ||
1341 | cfqq = cfq_find_cfq_hash(cfqd, cfq_hash_key(cfqd, current)); | |
1342 | if (cfqq) { | |
1343 | int limit = cfqd->max_queued; | |
1344 | ||
1345 | if (cfqq->allocated[rw] < cfqd->cfq_queued) | |
1346 | return ELV_MQUEUE_MUST; | |
1347 | ||
1348 | if (cfqd->busy_queues) | |
1349 | limit = q->nr_requests / cfqd->busy_queues; | |
1350 | ||
1351 | if (limit < cfqd->cfq_queued) | |
1352 | limit = cfqd->cfq_queued; | |
1353 | else if (limit > cfqd->max_queued) | |
1354 | limit = cfqd->max_queued; | |
1355 | ||
1356 | if (cfqq->allocated[rw] >= limit) { | |
1357 | if (limit > cfqq->alloc_limit[rw]) | |
1358 | cfqq->alloc_limit[rw] = limit; | |
1359 | ||
1360 | ret = ELV_MQUEUE_NO; | |
1361 | } | |
1362 | } | |
1363 | ||
1364 | return ret; | |
1365 | } | |
1366 | ||
1367 | static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) | |
1368 | { | |
1369 | struct request_list *rl = &q->rq; | |
1370 | const int write = waitqueue_active(&rl->wait[WRITE]); | |
1371 | const int read = waitqueue_active(&rl->wait[READ]); | |
1372 | ||
1373 | if (read && cfqq->allocated[READ] < cfqq->alloc_limit[READ]) | |
1374 | wake_up(&rl->wait[READ]); | |
1375 | if (write && cfqq->allocated[WRITE] < cfqq->alloc_limit[WRITE]) | |
1376 | wake_up(&rl->wait[WRITE]); | |
1377 | } | |
1378 | ||
1379 | /* | |
1380 | * queue lock held here | |
1381 | */ | |
1382 | static void cfq_put_request(request_queue_t *q, struct request *rq) | |
1383 | { | |
1384 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1385 | struct cfq_rq *crq = RQ_DATA(rq); | |
1386 | ||
1387 | if (crq) { | |
1388 | struct cfq_queue *cfqq = crq->cfq_queue; | |
1389 | ||
1390 | BUG_ON(q->last_merge == rq); | |
1391 | BUG_ON(!hlist_unhashed(&crq->hash)); | |
1392 | ||
1393 | if (crq->io_context) | |
1394 | put_io_context(crq->io_context->ioc); | |
1395 | ||
1396 | BUG_ON(!cfqq->allocated[crq->is_write]); | |
1397 | cfqq->allocated[crq->is_write]--; | |
1398 | ||
1399 | mempool_free(crq, cfqd->crq_pool); | |
1400 | rq->elevator_private = NULL; | |
1401 | ||
1402 | smp_mb(); | |
1403 | cfq_check_waiters(q, cfqq); | |
1404 | cfq_put_queue(cfqq); | |
1405 | } | |
1406 | } | |
1407 | ||
1408 | /* | |
1409 | * Allocate cfq data structures associated with this request. A queue and | |
1410 | */ | |
1411 | static int cfq_set_request(request_queue_t *q, struct request *rq, int gfp_mask) | |
1412 | { | |
1413 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1414 | struct cfq_io_context *cic; | |
1415 | const int rw = rq_data_dir(rq); | |
1416 | struct cfq_queue *cfqq, *saved_cfqq; | |
1417 | struct cfq_rq *crq; | |
1418 | unsigned long flags; | |
1419 | ||
1420 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
1421 | ||
1422 | spin_lock_irqsave(q->queue_lock, flags); | |
1423 | ||
1424 | cfqq = __cfq_get_queue(cfqd, cfq_hash_key(cfqd, current), gfp_mask); | |
1425 | if (!cfqq) | |
1426 | goto out_lock; | |
1427 | ||
1428 | repeat: | |
1429 | if (cfqq->allocated[rw] >= cfqd->max_queued) | |
1430 | goto out_lock; | |
1431 | ||
1432 | cfqq->allocated[rw]++; | |
1433 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1434 | ||
1435 | /* | |
1436 | * if hashing type has changed, the cfq_queue might change here. | |
1437 | */ | |
1438 | saved_cfqq = cfqq; | |
1439 | cic = cfq_get_io_context(&cfqq, gfp_mask); | |
1440 | if (!cic) | |
1441 | goto err; | |
1442 | ||
1443 | /* | |
1444 | * repeat allocation checks on queue change | |
1445 | */ | |
1446 | if (unlikely(saved_cfqq != cfqq)) { | |
1447 | spin_lock_irqsave(q->queue_lock, flags); | |
1448 | saved_cfqq->allocated[rw]--; | |
1449 | goto repeat; | |
1450 | } | |
1451 | ||
1452 | crq = mempool_alloc(cfqd->crq_pool, gfp_mask); | |
1453 | if (crq) { | |
1454 | RB_CLEAR(&crq->rb_node); | |
1455 | crq->rb_key = 0; | |
1456 | crq->request = rq; | |
1457 | INIT_HLIST_NODE(&crq->hash); | |
1458 | crq->cfq_queue = cfqq; | |
1459 | crq->io_context = cic; | |
1460 | crq->service_start = crq->queue_start = 0; | |
1461 | crq->in_flight = crq->accounted = crq->is_sync = 0; | |
1462 | crq->is_write = rw; | |
1463 | rq->elevator_private = crq; | |
1464 | cfqq->alloc_limit[rw] = 0; | |
1465 | return 0; | |
1466 | } | |
1467 | ||
1468 | put_io_context(cic->ioc); | |
1469 | err: | |
1470 | spin_lock_irqsave(q->queue_lock, flags); | |
1471 | cfqq->allocated[rw]--; | |
1472 | cfq_put_queue(cfqq); | |
1473 | out_lock: | |
1474 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1475 | return 1; | |
1476 | } | |
1477 | ||
1478 | static void cfq_put_cfqd(struct cfq_data *cfqd) | |
1479 | { | |
1480 | request_queue_t *q = cfqd->queue; | |
1481 | ||
1482 | if (!atomic_dec_and_test(&cfqd->ref)) | |
1483 | return; | |
1484 | ||
1485 | blk_put_queue(q); | |
1486 | ||
1487 | mempool_destroy(cfqd->crq_pool); | |
1488 | kfree(cfqd->crq_hash); | |
1489 | kfree(cfqd->cfq_hash); | |
1490 | kfree(cfqd); | |
1491 | } | |
1492 | ||
1493 | static void cfq_exit_queue(elevator_t *e) | |
1494 | { | |
1495 | cfq_put_cfqd(e->elevator_data); | |
1496 | } | |
1497 | ||
1498 | static int cfq_init_queue(request_queue_t *q, elevator_t *e) | |
1499 | { | |
1500 | struct cfq_data *cfqd; | |
1501 | int i; | |
1502 | ||
1503 | cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); | |
1504 | if (!cfqd) | |
1505 | return -ENOMEM; | |
1506 | ||
1507 | memset(cfqd, 0, sizeof(*cfqd)); | |
1508 | INIT_LIST_HEAD(&cfqd->rr_list); | |
1509 | INIT_LIST_HEAD(&cfqd->empty_list); | |
1510 | ||
1511 | cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); | |
1512 | if (!cfqd->crq_hash) | |
1513 | goto out_crqhash; | |
1514 | ||
1515 | cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); | |
1516 | if (!cfqd->cfq_hash) | |
1517 | goto out_cfqhash; | |
1518 | ||
1519 | cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool); | |
1520 | if (!cfqd->crq_pool) | |
1521 | goto out_crqpool; | |
1522 | ||
1523 | for (i = 0; i < CFQ_MHASH_ENTRIES; i++) | |
1524 | INIT_HLIST_HEAD(&cfqd->crq_hash[i]); | |
1525 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) | |
1526 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); | |
1527 | ||
1528 | e->elevator_data = cfqd; | |
1529 | ||
1530 | cfqd->queue = q; | |
1531 | atomic_inc(&q->refcnt); | |
1532 | ||
1533 | /* | |
1534 | * just set it to some high value, we want anyone to be able to queue | |
1535 | * some requests. fairness is handled differently | |
1536 | */ | |
1537 | q->nr_requests = 1024; | |
1538 | cfqd->max_queued = q->nr_requests / 16; | |
1539 | q->nr_batching = cfq_queued; | |
1540 | cfqd->key_type = CFQ_KEY_TGID; | |
1541 | cfqd->find_best_crq = 1; | |
1542 | atomic_set(&cfqd->ref, 1); | |
1543 | ||
1544 | cfqd->cfq_queued = cfq_queued; | |
1545 | cfqd->cfq_quantum = cfq_quantum; | |
1546 | cfqd->cfq_fifo_expire_r = cfq_fifo_expire_r; | |
1547 | cfqd->cfq_fifo_expire_w = cfq_fifo_expire_w; | |
1548 | cfqd->cfq_fifo_batch_expire = cfq_fifo_rate; | |
1549 | cfqd->cfq_back_max = cfq_back_max; | |
1550 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
1551 | ||
1552 | return 0; | |
1553 | out_crqpool: | |
1554 | kfree(cfqd->cfq_hash); | |
1555 | out_cfqhash: | |
1556 | kfree(cfqd->crq_hash); | |
1557 | out_crqhash: | |
1558 | kfree(cfqd); | |
1559 | return -ENOMEM; | |
1560 | } | |
1561 | ||
1562 | static void cfq_slab_kill(void) | |
1563 | { | |
1564 | if (crq_pool) | |
1565 | kmem_cache_destroy(crq_pool); | |
1566 | if (cfq_pool) | |
1567 | kmem_cache_destroy(cfq_pool); | |
1568 | if (cfq_ioc_pool) | |
1569 | kmem_cache_destroy(cfq_ioc_pool); | |
1570 | } | |
1571 | ||
1572 | static int __init cfq_slab_setup(void) | |
1573 | { | |
1574 | crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, | |
1575 | NULL, NULL); | |
1576 | if (!crq_pool) | |
1577 | goto fail; | |
1578 | ||
1579 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, | |
1580 | NULL, NULL); | |
1581 | if (!cfq_pool) | |
1582 | goto fail; | |
1583 | ||
1584 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", | |
1585 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); | |
1586 | if (!cfq_ioc_pool) | |
1587 | goto fail; | |
1588 | ||
1589 | return 0; | |
1590 | fail: | |
1591 | cfq_slab_kill(); | |
1592 | return -ENOMEM; | |
1593 | } | |
1594 | ||
1595 | ||
1596 | /* | |
1597 | * sysfs parts below --> | |
1598 | */ | |
1599 | struct cfq_fs_entry { | |
1600 | struct attribute attr; | |
1601 | ssize_t (*show)(struct cfq_data *, char *); | |
1602 | ssize_t (*store)(struct cfq_data *, const char *, size_t); | |
1603 | }; | |
1604 | ||
1605 | static ssize_t | |
1606 | cfq_var_show(unsigned int var, char *page) | |
1607 | { | |
1608 | return sprintf(page, "%d\n", var); | |
1609 | } | |
1610 | ||
1611 | static ssize_t | |
1612 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
1613 | { | |
1614 | char *p = (char *) page; | |
1615 | ||
1616 | *var = simple_strtoul(p, &p, 10); | |
1617 | return count; | |
1618 | } | |
1619 | ||
1620 | static ssize_t | |
1621 | cfq_clear_elapsed(struct cfq_data *cfqd, const char *page, size_t count) | |
1622 | { | |
1623 | max_elapsed_dispatch = max_elapsed_crq = 0; | |
1624 | return count; | |
1625 | } | |
1626 | ||
1627 | static ssize_t | |
1628 | cfq_set_key_type(struct cfq_data *cfqd, const char *page, size_t count) | |
1629 | { | |
1630 | spin_lock_irq(cfqd->queue->queue_lock); | |
1631 | if (!strncmp(page, "pgid", 4)) | |
1632 | cfqd->key_type = CFQ_KEY_PGID; | |
1633 | else if (!strncmp(page, "tgid", 4)) | |
1634 | cfqd->key_type = CFQ_KEY_TGID; | |
1635 | else if (!strncmp(page, "uid", 3)) | |
1636 | cfqd->key_type = CFQ_KEY_UID; | |
1637 | else if (!strncmp(page, "gid", 3)) | |
1638 | cfqd->key_type = CFQ_KEY_GID; | |
1639 | spin_unlock_irq(cfqd->queue->queue_lock); | |
1640 | return count; | |
1641 | } | |
1642 | ||
1643 | static ssize_t | |
1644 | cfq_read_key_type(struct cfq_data *cfqd, char *page) | |
1645 | { | |
1646 | ssize_t len = 0; | |
1647 | int i; | |
1648 | ||
1649 | for (i = CFQ_KEY_PGID; i < CFQ_KEY_LAST; i++) { | |
1650 | if (cfqd->key_type == i) | |
1651 | len += sprintf(page+len, "[%s] ", cfq_key_types[i]); | |
1652 | else | |
1653 | len += sprintf(page+len, "%s ", cfq_key_types[i]); | |
1654 | } | |
1655 | len += sprintf(page+len, "\n"); | |
1656 | return len; | |
1657 | } | |
1658 | ||
1659 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ | |
1660 | static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \ | |
1661 | { \ | |
1662 | unsigned int __data = __VAR; \ | |
1663 | if (__CONV) \ | |
1664 | __data = jiffies_to_msecs(__data); \ | |
1665 | return cfq_var_show(__data, (page)); \ | |
1666 | } | |
1667 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
1668 | SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); | |
1669 | SHOW_FUNCTION(cfq_fifo_expire_r_show, cfqd->cfq_fifo_expire_r, 1); | |
1670 | SHOW_FUNCTION(cfq_fifo_expire_w_show, cfqd->cfq_fifo_expire_w, 1); | |
1671 | SHOW_FUNCTION(cfq_fifo_batch_expire_show, cfqd->cfq_fifo_batch_expire, 1); | |
1672 | SHOW_FUNCTION(cfq_find_best_show, cfqd->find_best_crq, 0); | |
1673 | SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); | |
1674 | SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); | |
1675 | #undef SHOW_FUNCTION | |
1676 | ||
1677 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
1678 | static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \ | |
1679 | { \ | |
1680 | unsigned int __data; \ | |
1681 | int ret = cfq_var_store(&__data, (page), count); \ | |
1682 | if (__data < (MIN)) \ | |
1683 | __data = (MIN); \ | |
1684 | else if (__data > (MAX)) \ | |
1685 | __data = (MAX); \ | |
1686 | if (__CONV) \ | |
1687 | *(__PTR) = msecs_to_jiffies(__data); \ | |
1688 | else \ | |
1689 | *(__PTR) = __data; \ | |
1690 | return ret; \ | |
1691 | } | |
1692 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
1693 | STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); | |
1694 | STORE_FUNCTION(cfq_fifo_expire_r_store, &cfqd->cfq_fifo_expire_r, 1, UINT_MAX, 1); | |
1695 | STORE_FUNCTION(cfq_fifo_expire_w_store, &cfqd->cfq_fifo_expire_w, 1, UINT_MAX, 1); | |
1696 | STORE_FUNCTION(cfq_fifo_batch_expire_store, &cfqd->cfq_fifo_batch_expire, 0, UINT_MAX, 1); | |
1697 | STORE_FUNCTION(cfq_find_best_store, &cfqd->find_best_crq, 0, 1, 0); | |
1698 | STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); | |
1699 | STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); | |
1700 | #undef STORE_FUNCTION | |
1701 | ||
1702 | static struct cfq_fs_entry cfq_quantum_entry = { | |
1703 | .attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR }, | |
1704 | .show = cfq_quantum_show, | |
1705 | .store = cfq_quantum_store, | |
1706 | }; | |
1707 | static struct cfq_fs_entry cfq_queued_entry = { | |
1708 | .attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR }, | |
1709 | .show = cfq_queued_show, | |
1710 | .store = cfq_queued_store, | |
1711 | }; | |
1712 | static struct cfq_fs_entry cfq_fifo_expire_r_entry = { | |
1713 | .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, | |
1714 | .show = cfq_fifo_expire_r_show, | |
1715 | .store = cfq_fifo_expire_r_store, | |
1716 | }; | |
1717 | static struct cfq_fs_entry cfq_fifo_expire_w_entry = { | |
1718 | .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, | |
1719 | .show = cfq_fifo_expire_w_show, | |
1720 | .store = cfq_fifo_expire_w_store, | |
1721 | }; | |
1722 | static struct cfq_fs_entry cfq_fifo_batch_expire_entry = { | |
1723 | .attr = {.name = "fifo_batch_expire", .mode = S_IRUGO | S_IWUSR }, | |
1724 | .show = cfq_fifo_batch_expire_show, | |
1725 | .store = cfq_fifo_batch_expire_store, | |
1726 | }; | |
1727 | static struct cfq_fs_entry cfq_find_best_entry = { | |
1728 | .attr = {.name = "find_best_crq", .mode = S_IRUGO | S_IWUSR }, | |
1729 | .show = cfq_find_best_show, | |
1730 | .store = cfq_find_best_store, | |
1731 | }; | |
1732 | static struct cfq_fs_entry cfq_back_max_entry = { | |
1733 | .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR }, | |
1734 | .show = cfq_back_max_show, | |
1735 | .store = cfq_back_max_store, | |
1736 | }; | |
1737 | static struct cfq_fs_entry cfq_back_penalty_entry = { | |
1738 | .attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR }, | |
1739 | .show = cfq_back_penalty_show, | |
1740 | .store = cfq_back_penalty_store, | |
1741 | }; | |
1742 | static struct cfq_fs_entry cfq_clear_elapsed_entry = { | |
1743 | .attr = {.name = "clear_elapsed", .mode = S_IWUSR }, | |
1744 | .store = cfq_clear_elapsed, | |
1745 | }; | |
1746 | static struct cfq_fs_entry cfq_key_type_entry = { | |
1747 | .attr = {.name = "key_type", .mode = S_IRUGO | S_IWUSR }, | |
1748 | .show = cfq_read_key_type, | |
1749 | .store = cfq_set_key_type, | |
1750 | }; | |
1751 | ||
1752 | static struct attribute *default_attrs[] = { | |
1753 | &cfq_quantum_entry.attr, | |
1754 | &cfq_queued_entry.attr, | |
1755 | &cfq_fifo_expire_r_entry.attr, | |
1756 | &cfq_fifo_expire_w_entry.attr, | |
1757 | &cfq_fifo_batch_expire_entry.attr, | |
1758 | &cfq_key_type_entry.attr, | |
1759 | &cfq_find_best_entry.attr, | |
1760 | &cfq_back_max_entry.attr, | |
1761 | &cfq_back_penalty_entry.attr, | |
1762 | &cfq_clear_elapsed_entry.attr, | |
1763 | NULL, | |
1764 | }; | |
1765 | ||
1766 | #define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr) | |
1767 | ||
1768 | static ssize_t | |
1769 | cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page) | |
1770 | { | |
1771 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
1772 | struct cfq_fs_entry *entry = to_cfq(attr); | |
1773 | ||
1774 | if (!entry->show) | |
1775 | return 0; | |
1776 | ||
1777 | return entry->show(e->elevator_data, page); | |
1778 | } | |
1779 | ||
1780 | static ssize_t | |
1781 | cfq_attr_store(struct kobject *kobj, struct attribute *attr, | |
1782 | const char *page, size_t length) | |
1783 | { | |
1784 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
1785 | struct cfq_fs_entry *entry = to_cfq(attr); | |
1786 | ||
1787 | if (!entry->store) | |
1788 | return -EINVAL; | |
1789 | ||
1790 | return entry->store(e->elevator_data, page, length); | |
1791 | } | |
1792 | ||
1793 | static struct sysfs_ops cfq_sysfs_ops = { | |
1794 | .show = cfq_attr_show, | |
1795 | .store = cfq_attr_store, | |
1796 | }; | |
1797 | ||
1798 | static struct kobj_type cfq_ktype = { | |
1799 | .sysfs_ops = &cfq_sysfs_ops, | |
1800 | .default_attrs = default_attrs, | |
1801 | }; | |
1802 | ||
1803 | static struct elevator_type iosched_cfq = { | |
1804 | .ops = { | |
1805 | .elevator_merge_fn = cfq_merge, | |
1806 | .elevator_merged_fn = cfq_merged_request, | |
1807 | .elevator_merge_req_fn = cfq_merged_requests, | |
1808 | .elevator_next_req_fn = cfq_next_request, | |
1809 | .elevator_add_req_fn = cfq_insert_request, | |
1810 | .elevator_remove_req_fn = cfq_remove_request, | |
1811 | .elevator_requeue_req_fn = cfq_requeue_request, | |
1812 | .elevator_deactivate_req_fn = cfq_deactivate_request, | |
1813 | .elevator_queue_empty_fn = cfq_queue_empty, | |
1814 | .elevator_completed_req_fn = cfq_completed_request, | |
1815 | .elevator_former_req_fn = cfq_former_request, | |
1816 | .elevator_latter_req_fn = cfq_latter_request, | |
1817 | .elevator_set_req_fn = cfq_set_request, | |
1818 | .elevator_put_req_fn = cfq_put_request, | |
1819 | .elevator_may_queue_fn = cfq_may_queue, | |
1820 | .elevator_init_fn = cfq_init_queue, | |
1821 | .elevator_exit_fn = cfq_exit_queue, | |
1822 | }, | |
1823 | .elevator_ktype = &cfq_ktype, | |
1824 | .elevator_name = "cfq", | |
1825 | .elevator_owner = THIS_MODULE, | |
1826 | }; | |
1827 | ||
1828 | static int __init cfq_init(void) | |
1829 | { | |
1830 | int ret; | |
1831 | ||
1832 | if (cfq_slab_setup()) | |
1833 | return -ENOMEM; | |
1834 | ||
1835 | ret = elv_register(&iosched_cfq); | |
1836 | if (!ret) { | |
1837 | __module_get(THIS_MODULE); | |
1838 | return 0; | |
1839 | } | |
1840 | ||
1841 | cfq_slab_kill(); | |
1842 | return ret; | |
1843 | } | |
1844 | ||
1845 | static void __exit cfq_exit(void) | |
1846 | { | |
1847 | cfq_slab_kill(); | |
1848 | elv_unregister(&iosched_cfq); | |
1849 | } | |
1850 | ||
1851 | module_init(cfq_init); | |
1852 | module_exit(cfq_exit); | |
1853 | ||
1854 | MODULE_AUTHOR("Jens Axboe"); | |
1855 | MODULE_LICENSE("GPL"); | |
1856 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |