Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * CFQ, or complete fairness queueing, disk scheduler. |
3 | * | |
4 | * Based on ideas from a previously unfinished io | |
5 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. | |
6 | * | |
7 | * Copyright (C) 2003 Jens Axboe <axboe@suse.de> | |
8 | */ | |
1da177e4 LT |
9 | #include <linux/config.h> |
10 | #include <linux/module.h> | |
1cc9be68 AV |
11 | #include <linux/blkdev.h> |
12 | #include <linux/elevator.h> | |
1da177e4 LT |
13 | #include <linux/hash.h> |
14 | #include <linux/rbtree.h> | |
22e2c507 | 15 | #include <linux/ioprio.h> |
1da177e4 LT |
16 | |
17 | /* | |
18 | * tunables | |
19 | */ | |
64100099 AV |
20 | static const int cfq_quantum = 4; /* max queue in one round of service */ |
21 | static const int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ | |
22 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; | |
23 | static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ | |
24 | static const int cfq_back_penalty = 2; /* penalty of a backwards seek */ | |
1da177e4 | 25 | |
64100099 | 26 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 27 | static int cfq_slice_async = HZ / 25; |
64100099 | 28 | static const int cfq_slice_async_rq = 2; |
3b18152c | 29 | static int cfq_slice_idle = HZ / 100; |
22e2c507 JA |
30 | |
31 | #define CFQ_IDLE_GRACE (HZ / 10) | |
32 | #define CFQ_SLICE_SCALE (5) | |
33 | ||
34 | #define CFQ_KEY_ASYNC (0) | |
3b18152c | 35 | #define CFQ_KEY_ANY (0xffff) |
22e2c507 JA |
36 | |
37 | /* | |
38 | * disable queueing at the driver/hardware level | |
39 | */ | |
64100099 | 40 | static const int cfq_max_depth = 2; |
22e2c507 | 41 | |
a6a0763a AV |
42 | static DEFINE_RWLOCK(cfq_exit_lock); |
43 | ||
1da177e4 LT |
44 | /* |
45 | * for the hash of cfqq inside the cfqd | |
46 | */ | |
47 | #define CFQ_QHASH_SHIFT 6 | |
48 | #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) | |
49 | #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) | |
50 | ||
51 | /* | |
52 | * for the hash of crq inside the cfqq | |
53 | */ | |
54 | #define CFQ_MHASH_SHIFT 6 | |
55 | #define CFQ_MHASH_BLOCK(sec) ((sec) >> 3) | |
56 | #define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT) | |
57 | #define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT) | |
58 | #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) | |
59 | #define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash) | |
60 | ||
61 | #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) | |
22e2c507 | 62 | #define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
1da177e4 LT |
63 | |
64 | #define RQ_DATA(rq) (rq)->elevator_private | |
65 | ||
66 | /* | |
67 | * rb-tree defines | |
68 | */ | |
69 | #define RB_NONE (2) | |
70 | #define RB_EMPTY(node) ((node)->rb_node == NULL) | |
71 | #define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE | |
72 | #define RB_CLEAR(node) do { \ | |
73 | (node)->rb_parent = NULL; \ | |
74 | RB_CLEAR_COLOR((node)); \ | |
75 | (node)->rb_right = NULL; \ | |
76 | (node)->rb_left = NULL; \ | |
77 | } while (0) | |
78 | #define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL) | |
1da177e4 LT |
79 | #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) |
80 | #define rq_rb_key(rq) (rq)->sector | |
81 | ||
1da177e4 LT |
82 | static kmem_cache_t *crq_pool; |
83 | static kmem_cache_t *cfq_pool; | |
84 | static kmem_cache_t *cfq_ioc_pool; | |
85 | ||
334e94de AV |
86 | static atomic_t ioc_count = ATOMIC_INIT(0); |
87 | static struct completion *ioc_gone; | |
88 | ||
22e2c507 JA |
89 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
90 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
91 | #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) | |
92 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) | |
93 | ||
3b18152c JA |
94 | #define ASYNC (0) |
95 | #define SYNC (1) | |
96 | ||
97 | #define cfq_cfqq_dispatched(cfqq) \ | |
98 | ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) | |
99 | ||
100 | #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) | |
101 | ||
102 | #define cfq_cfqq_sync(cfqq) \ | |
103 | (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) | |
22e2c507 JA |
104 | |
105 | /* | |
106 | * Per block device queue structure | |
107 | */ | |
1da177e4 | 108 | struct cfq_data { |
22e2c507 JA |
109 | request_queue_t *queue; |
110 | ||
111 | /* | |
112 | * rr list of queues with requests and the count of them | |
113 | */ | |
114 | struct list_head rr_list[CFQ_PRIO_LISTS]; | |
115 | struct list_head busy_rr; | |
116 | struct list_head cur_rr; | |
117 | struct list_head idle_rr; | |
118 | unsigned int busy_queues; | |
119 | ||
120 | /* | |
121 | * non-ordered list of empty cfqq's | |
122 | */ | |
1da177e4 LT |
123 | struct list_head empty_list; |
124 | ||
22e2c507 JA |
125 | /* |
126 | * cfqq lookup hash | |
127 | */ | |
1da177e4 | 128 | struct hlist_head *cfq_hash; |
1da177e4 | 129 | |
22e2c507 JA |
130 | /* |
131 | * global crq hash for all queues | |
132 | */ | |
133 | struct hlist_head *crq_hash; | |
1da177e4 LT |
134 | |
135 | unsigned int max_queued; | |
136 | ||
22e2c507 | 137 | mempool_t *crq_pool; |
1da177e4 | 138 | |
22e2c507 | 139 | int rq_in_driver; |
1da177e4 | 140 | |
22e2c507 JA |
141 | /* |
142 | * schedule slice state info | |
143 | */ | |
144 | /* | |
145 | * idle window management | |
146 | */ | |
147 | struct timer_list idle_slice_timer; | |
148 | struct work_struct unplug_work; | |
1da177e4 | 149 | |
22e2c507 JA |
150 | struct cfq_queue *active_queue; |
151 | struct cfq_io_context *active_cic; | |
152 | int cur_prio, cur_end_prio; | |
153 | unsigned int dispatch_slice; | |
154 | ||
155 | struct timer_list idle_class_timer; | |
1da177e4 LT |
156 | |
157 | sector_t last_sector; | |
22e2c507 | 158 | unsigned long last_end_request; |
1da177e4 | 159 | |
22e2c507 | 160 | unsigned int rq_starved; |
1da177e4 LT |
161 | |
162 | /* | |
163 | * tunables, see top of file | |
164 | */ | |
165 | unsigned int cfq_quantum; | |
166 | unsigned int cfq_queued; | |
22e2c507 | 167 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
168 | unsigned int cfq_back_penalty; |
169 | unsigned int cfq_back_max; | |
22e2c507 JA |
170 | unsigned int cfq_slice[2]; |
171 | unsigned int cfq_slice_async_rq; | |
172 | unsigned int cfq_slice_idle; | |
173 | unsigned int cfq_max_depth; | |
d9ff4187 AV |
174 | |
175 | struct list_head cic_list; | |
1da177e4 LT |
176 | }; |
177 | ||
22e2c507 JA |
178 | /* |
179 | * Per process-grouping structure | |
180 | */ | |
1da177e4 LT |
181 | struct cfq_queue { |
182 | /* reference count */ | |
183 | atomic_t ref; | |
184 | /* parent cfq_data */ | |
185 | struct cfq_data *cfqd; | |
22e2c507 | 186 | /* cfqq lookup hash */ |
1da177e4 LT |
187 | struct hlist_node cfq_hash; |
188 | /* hash key */ | |
22e2c507 | 189 | unsigned int key; |
1da177e4 LT |
190 | /* on either rr or empty list of cfqd */ |
191 | struct list_head cfq_list; | |
192 | /* sorted list of pending requests */ | |
193 | struct rb_root sort_list; | |
194 | /* if fifo isn't expired, next request to serve */ | |
195 | struct cfq_rq *next_crq; | |
196 | /* requests queued in sort_list */ | |
197 | int queued[2]; | |
198 | /* currently allocated requests */ | |
199 | int allocated[2]; | |
200 | /* fifo list of requests in sort_list */ | |
22e2c507 | 201 | struct list_head fifo; |
1da177e4 | 202 | |
22e2c507 JA |
203 | unsigned long slice_start; |
204 | unsigned long slice_end; | |
205 | unsigned long slice_left; | |
206 | unsigned long service_last; | |
1da177e4 | 207 | |
3b18152c JA |
208 | /* number of requests that are on the dispatch list */ |
209 | int on_dispatch[2]; | |
22e2c507 JA |
210 | |
211 | /* io prio of this group */ | |
212 | unsigned short ioprio, org_ioprio; | |
213 | unsigned short ioprio_class, org_ioprio_class; | |
214 | ||
3b18152c JA |
215 | /* various state flags, see below */ |
216 | unsigned int flags; | |
1da177e4 LT |
217 | }; |
218 | ||
219 | struct cfq_rq { | |
220 | struct rb_node rb_node; | |
221 | sector_t rb_key; | |
222 | struct request *request; | |
223 | struct hlist_node hash; | |
224 | ||
225 | struct cfq_queue *cfq_queue; | |
226 | struct cfq_io_context *io_context; | |
227 | ||
3b18152c | 228 | unsigned int crq_flags; |
1da177e4 LT |
229 | }; |
230 | ||
3b18152c JA |
231 | enum cfqq_state_flags { |
232 | CFQ_CFQQ_FLAG_on_rr = 0, | |
233 | CFQ_CFQQ_FLAG_wait_request, | |
234 | CFQ_CFQQ_FLAG_must_alloc, | |
235 | CFQ_CFQQ_FLAG_must_alloc_slice, | |
236 | CFQ_CFQQ_FLAG_must_dispatch, | |
237 | CFQ_CFQQ_FLAG_fifo_expire, | |
238 | CFQ_CFQQ_FLAG_idle_window, | |
239 | CFQ_CFQQ_FLAG_prio_changed, | |
3b18152c JA |
240 | }; |
241 | ||
242 | #define CFQ_CFQQ_FNS(name) \ | |
243 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
244 | { \ | |
245 | cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ | |
246 | } \ | |
247 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
248 | { \ | |
249 | cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ | |
250 | } \ | |
251 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
252 | { \ | |
253 | return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ | |
254 | } | |
255 | ||
256 | CFQ_CFQQ_FNS(on_rr); | |
257 | CFQ_CFQQ_FNS(wait_request); | |
258 | CFQ_CFQQ_FNS(must_alloc); | |
259 | CFQ_CFQQ_FNS(must_alloc_slice); | |
260 | CFQ_CFQQ_FNS(must_dispatch); | |
261 | CFQ_CFQQ_FNS(fifo_expire); | |
262 | CFQ_CFQQ_FNS(idle_window); | |
263 | CFQ_CFQQ_FNS(prio_changed); | |
3b18152c JA |
264 | #undef CFQ_CFQQ_FNS |
265 | ||
266 | enum cfq_rq_state_flags { | |
b4878f24 | 267 | CFQ_CRQ_FLAG_is_sync = 0, |
3b18152c JA |
268 | }; |
269 | ||
270 | #define CFQ_CRQ_FNS(name) \ | |
271 | static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \ | |
272 | { \ | |
273 | crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \ | |
274 | } \ | |
275 | static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \ | |
276 | { \ | |
277 | crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \ | |
278 | } \ | |
279 | static inline int cfq_crq_##name(const struct cfq_rq *crq) \ | |
280 | { \ | |
281 | return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \ | |
282 | } | |
283 | ||
3b18152c | 284 | CFQ_CRQ_FNS(is_sync); |
3b18152c JA |
285 | #undef CFQ_CRQ_FNS |
286 | ||
287 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); | |
b4878f24 | 288 | static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); |
6f325a13 | 289 | static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); |
1da177e4 | 290 | |
22e2c507 | 291 | #define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) |
1da177e4 LT |
292 | |
293 | /* | |
294 | * lots of deadline iosched dupes, can be abstracted later... | |
295 | */ | |
296 | static inline void cfq_del_crq_hash(struct cfq_rq *crq) | |
297 | { | |
298 | hlist_del_init(&crq->hash); | |
299 | } | |
300 | ||
1da177e4 LT |
301 | static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) |
302 | { | |
303 | const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); | |
304 | ||
1da177e4 LT |
305 | hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); |
306 | } | |
307 | ||
308 | static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) | |
309 | { | |
310 | struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)]; | |
311 | struct hlist_node *entry, *next; | |
312 | ||
313 | hlist_for_each_safe(entry, next, hash_list) { | |
314 | struct cfq_rq *crq = list_entry_hash(entry); | |
315 | struct request *__rq = crq->request; | |
316 | ||
1da177e4 LT |
317 | if (!rq_mergeable(__rq)) { |
318 | cfq_del_crq_hash(crq); | |
319 | continue; | |
320 | } | |
321 | ||
322 | if (rq_hash_key(__rq) == offset) | |
323 | return __rq; | |
324 | } | |
325 | ||
326 | return NULL; | |
327 | } | |
328 | ||
99f95e52 AM |
329 | /* |
330 | * scheduler run of queue, if there are requests pending and no one in the | |
331 | * driver that will restart queueing | |
332 | */ | |
333 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) | |
334 | { | |
7b14e3b5 | 335 | if (cfqd->busy_queues) |
99f95e52 AM |
336 | kblockd_schedule_work(&cfqd->unplug_work); |
337 | } | |
338 | ||
339 | static int cfq_queue_empty(request_queue_t *q) | |
340 | { | |
341 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
342 | ||
b4878f24 | 343 | return !cfqd->busy_queues; |
99f95e52 AM |
344 | } |
345 | ||
1da177e4 LT |
346 | /* |
347 | * Lifted from AS - choose which of crq1 and crq2 that is best served now. | |
348 | * We choose the request that is closest to the head right now. Distance | |
349 | * behind the head are penalized and only allowed to a certain extent. | |
350 | */ | |
351 | static struct cfq_rq * | |
352 | cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) | |
353 | { | |
354 | sector_t last, s1, s2, d1 = 0, d2 = 0; | |
355 | int r1_wrap = 0, r2_wrap = 0; /* requests are behind the disk head */ | |
356 | unsigned long back_max; | |
357 | ||
358 | if (crq1 == NULL || crq1 == crq2) | |
359 | return crq2; | |
360 | if (crq2 == NULL) | |
361 | return crq1; | |
9c2c38a1 | 362 | |
9c2c38a1 JA |
363 | if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2)) |
364 | return crq1; | |
365 | else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1)) | |
22e2c507 | 366 | return crq2; |
1da177e4 LT |
367 | |
368 | s1 = crq1->request->sector; | |
369 | s2 = crq2->request->sector; | |
370 | ||
371 | last = cfqd->last_sector; | |
372 | ||
1da177e4 LT |
373 | /* |
374 | * by definition, 1KiB is 2 sectors | |
375 | */ | |
376 | back_max = cfqd->cfq_back_max * 2; | |
377 | ||
378 | /* | |
379 | * Strict one way elevator _except_ in the case where we allow | |
380 | * short backward seeks which are biased as twice the cost of a | |
381 | * similar forward seek. | |
382 | */ | |
383 | if (s1 >= last) | |
384 | d1 = s1 - last; | |
385 | else if (s1 + back_max >= last) | |
386 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
387 | else | |
388 | r1_wrap = 1; | |
389 | ||
390 | if (s2 >= last) | |
391 | d2 = s2 - last; | |
392 | else if (s2 + back_max >= last) | |
393 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
394 | else | |
395 | r2_wrap = 1; | |
396 | ||
397 | /* Found required data */ | |
398 | if (!r1_wrap && r2_wrap) | |
399 | return crq1; | |
400 | else if (!r2_wrap && r1_wrap) | |
401 | return crq2; | |
402 | else if (r1_wrap && r2_wrap) { | |
403 | /* both behind the head */ | |
404 | if (s1 <= s2) | |
405 | return crq1; | |
406 | else | |
407 | return crq2; | |
408 | } | |
409 | ||
410 | /* Both requests in front of the head */ | |
411 | if (d1 < d2) | |
412 | return crq1; | |
413 | else if (d2 < d1) | |
414 | return crq2; | |
415 | else { | |
416 | if (s1 >= s2) | |
417 | return crq1; | |
418 | else | |
419 | return crq2; | |
420 | } | |
421 | } | |
422 | ||
423 | /* | |
424 | * would be nice to take fifo expire time into account as well | |
425 | */ | |
426 | static struct cfq_rq * | |
427 | cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
428 | struct cfq_rq *last) | |
429 | { | |
430 | struct cfq_rq *crq_next = NULL, *crq_prev = NULL; | |
431 | struct rb_node *rbnext, *rbprev; | |
432 | ||
b4878f24 | 433 | if (!(rbnext = rb_next(&last->rb_node))) { |
1da177e4 | 434 | rbnext = rb_first(&cfqq->sort_list); |
22e2c507 JA |
435 | if (rbnext == &last->rb_node) |
436 | rbnext = NULL; | |
437 | } | |
1da177e4 LT |
438 | |
439 | rbprev = rb_prev(&last->rb_node); | |
440 | ||
441 | if (rbprev) | |
442 | crq_prev = rb_entry_crq(rbprev); | |
443 | if (rbnext) | |
444 | crq_next = rb_entry_crq(rbnext); | |
445 | ||
446 | return cfq_choose_req(cfqd, crq_next, crq_prev); | |
447 | } | |
448 | ||
449 | static void cfq_update_next_crq(struct cfq_rq *crq) | |
450 | { | |
451 | struct cfq_queue *cfqq = crq->cfq_queue; | |
452 | ||
453 | if (cfqq->next_crq == crq) | |
454 | cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); | |
455 | } | |
456 | ||
22e2c507 | 457 | static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
1da177e4 | 458 | { |
22e2c507 JA |
459 | struct cfq_data *cfqd = cfqq->cfqd; |
460 | struct list_head *list, *entry; | |
1da177e4 | 461 | |
3b18152c | 462 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 463 | |
22e2c507 | 464 | list_del(&cfqq->cfq_list); |
1da177e4 | 465 | |
22e2c507 JA |
466 | if (cfq_class_rt(cfqq)) |
467 | list = &cfqd->cur_rr; | |
468 | else if (cfq_class_idle(cfqq)) | |
469 | list = &cfqd->idle_rr; | |
470 | else { | |
471 | /* | |
472 | * if cfqq has requests in flight, don't allow it to be | |
473 | * found in cfq_set_active_queue before it has finished them. | |
474 | * this is done to increase fairness between a process that | |
475 | * has lots of io pending vs one that only generates one | |
476 | * sporadically or synchronously | |
477 | */ | |
3b18152c | 478 | if (cfq_cfqq_dispatched(cfqq)) |
22e2c507 JA |
479 | list = &cfqd->busy_rr; |
480 | else | |
481 | list = &cfqd->rr_list[cfqq->ioprio]; | |
1da177e4 LT |
482 | } |
483 | ||
22e2c507 JA |
484 | /* |
485 | * if queue was preempted, just add to front to be fair. busy_rr | |
486 | * isn't sorted. | |
487 | */ | |
488 | if (preempted || list == &cfqd->busy_rr) { | |
489 | list_add(&cfqq->cfq_list, list); | |
1da177e4 | 490 | return; |
22e2c507 | 491 | } |
1da177e4 LT |
492 | |
493 | /* | |
22e2c507 | 494 | * sort by when queue was last serviced |
1da177e4 | 495 | */ |
22e2c507 JA |
496 | entry = list; |
497 | while ((entry = entry->prev) != list) { | |
1da177e4 LT |
498 | struct cfq_queue *__cfqq = list_entry_cfqq(entry); |
499 | ||
22e2c507 JA |
500 | if (!__cfqq->service_last) |
501 | break; | |
502 | if (time_before(__cfqq->service_last, cfqq->service_last)) | |
1da177e4 | 503 | break; |
1da177e4 LT |
504 | } |
505 | ||
506 | list_add(&cfqq->cfq_list, entry); | |
507 | } | |
508 | ||
509 | /* | |
510 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 511 | * the pending list according to last request service |
1da177e4 LT |
512 | */ |
513 | static inline void | |
b4878f24 | 514 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 515 | { |
3b18152c JA |
516 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
517 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
518 | cfqd->busy_queues++; |
519 | ||
b4878f24 | 520 | cfq_resort_rr_list(cfqq, 0); |
1da177e4 LT |
521 | } |
522 | ||
523 | static inline void | |
524 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
525 | { | |
3b18152c JA |
526 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
527 | cfq_clear_cfqq_on_rr(cfqq); | |
22e2c507 | 528 | list_move(&cfqq->cfq_list, &cfqd->empty_list); |
1da177e4 LT |
529 | |
530 | BUG_ON(!cfqd->busy_queues); | |
531 | cfqd->busy_queues--; | |
532 | } | |
533 | ||
534 | /* | |
535 | * rb tree support functions | |
536 | */ | |
537 | static inline void cfq_del_crq_rb(struct cfq_rq *crq) | |
538 | { | |
539 | struct cfq_queue *cfqq = crq->cfq_queue; | |
b4878f24 JA |
540 | struct cfq_data *cfqd = cfqq->cfqd; |
541 | const int sync = cfq_crq_is_sync(crq); | |
1da177e4 | 542 | |
b4878f24 JA |
543 | BUG_ON(!cfqq->queued[sync]); |
544 | cfqq->queued[sync]--; | |
1da177e4 | 545 | |
b4878f24 | 546 | cfq_update_next_crq(crq); |
1da177e4 | 547 | |
b4878f24 JA |
548 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
549 | RB_CLEAR_COLOR(&crq->rb_node); | |
1da177e4 | 550 | |
b4878f24 JA |
551 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list)) |
552 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1da177e4 LT |
553 | } |
554 | ||
555 | static struct cfq_rq * | |
556 | __cfq_add_crq_rb(struct cfq_rq *crq) | |
557 | { | |
558 | struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; | |
559 | struct rb_node *parent = NULL; | |
560 | struct cfq_rq *__crq; | |
561 | ||
562 | while (*p) { | |
563 | parent = *p; | |
564 | __crq = rb_entry_crq(parent); | |
565 | ||
566 | if (crq->rb_key < __crq->rb_key) | |
567 | p = &(*p)->rb_left; | |
568 | else if (crq->rb_key > __crq->rb_key) | |
569 | p = &(*p)->rb_right; | |
570 | else | |
571 | return __crq; | |
572 | } | |
573 | ||
574 | rb_link_node(&crq->rb_node, parent, p); | |
575 | return NULL; | |
576 | } | |
577 | ||
578 | static void cfq_add_crq_rb(struct cfq_rq *crq) | |
579 | { | |
580 | struct cfq_queue *cfqq = crq->cfq_queue; | |
581 | struct cfq_data *cfqd = cfqq->cfqd; | |
582 | struct request *rq = crq->request; | |
583 | struct cfq_rq *__alias; | |
584 | ||
585 | crq->rb_key = rq_rb_key(rq); | |
3b18152c | 586 | cfqq->queued[cfq_crq_is_sync(crq)]++; |
1da177e4 LT |
587 | |
588 | /* | |
589 | * looks a little odd, but the first insert might return an alias. | |
590 | * if that happens, put the alias on the dispatch list | |
591 | */ | |
592 | while ((__alias = __cfq_add_crq_rb(crq)) != NULL) | |
b4878f24 | 593 | cfq_dispatch_insert(cfqd->queue, __alias); |
1da177e4 LT |
594 | |
595 | rb_insert_color(&crq->rb_node, &cfqq->sort_list); | |
596 | ||
3b18152c | 597 | if (!cfq_cfqq_on_rr(cfqq)) |
b4878f24 | 598 | cfq_add_cfqq_rr(cfqd, cfqq); |
1da177e4 LT |
599 | |
600 | /* | |
601 | * check if this request is a better next-serve candidate | |
602 | */ | |
603 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
604 | } | |
605 | ||
606 | static inline void | |
607 | cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) | |
608 | { | |
b4878f24 JA |
609 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
610 | cfqq->queued[cfq_crq_is_sync(crq)]--; | |
1da177e4 LT |
611 | |
612 | cfq_add_crq_rb(crq); | |
613 | } | |
614 | ||
22e2c507 JA |
615 | static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) |
616 | ||
1da177e4 | 617 | { |
3b18152c | 618 | struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY); |
1da177e4 LT |
619 | struct rb_node *n; |
620 | ||
621 | if (!cfqq) | |
622 | goto out; | |
623 | ||
624 | n = cfqq->sort_list.rb_node; | |
625 | while (n) { | |
626 | struct cfq_rq *crq = rb_entry_crq(n); | |
627 | ||
628 | if (sector < crq->rb_key) | |
629 | n = n->rb_left; | |
630 | else if (sector > crq->rb_key) | |
631 | n = n->rb_right; | |
632 | else | |
633 | return crq->request; | |
634 | } | |
635 | ||
636 | out: | |
637 | return NULL; | |
638 | } | |
639 | ||
b4878f24 | 640 | static void cfq_activate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 641 | { |
22e2c507 | 642 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 643 | |
b4878f24 | 644 | cfqd->rq_in_driver++; |
1da177e4 LT |
645 | } |
646 | ||
b4878f24 | 647 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 648 | { |
b4878f24 JA |
649 | struct cfq_data *cfqd = q->elevator->elevator_data; |
650 | ||
651 | WARN_ON(!cfqd->rq_in_driver); | |
652 | cfqd->rq_in_driver--; | |
1da177e4 LT |
653 | } |
654 | ||
b4878f24 | 655 | static void cfq_remove_request(struct request *rq) |
1da177e4 LT |
656 | { |
657 | struct cfq_rq *crq = RQ_DATA(rq); | |
658 | ||
b4878f24 JA |
659 | list_del_init(&rq->queuelist); |
660 | cfq_del_crq_rb(crq); | |
98b11471 | 661 | cfq_del_crq_hash(crq); |
1da177e4 LT |
662 | } |
663 | ||
664 | static int | |
665 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
666 | { | |
667 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
668 | struct request *__rq; | |
669 | int ret; | |
670 | ||
1da177e4 | 671 | __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); |
22e2c507 JA |
672 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
673 | ret = ELEVATOR_BACK_MERGE; | |
674 | goto out; | |
1da177e4 LT |
675 | } |
676 | ||
677 | __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); | |
22e2c507 JA |
678 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
679 | ret = ELEVATOR_FRONT_MERGE; | |
680 | goto out; | |
1da177e4 LT |
681 | } |
682 | ||
683 | return ELEVATOR_NO_MERGE; | |
684 | out: | |
1da177e4 LT |
685 | *req = __rq; |
686 | return ret; | |
687 | } | |
688 | ||
689 | static void cfq_merged_request(request_queue_t *q, struct request *req) | |
690 | { | |
691 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
692 | struct cfq_rq *crq = RQ_DATA(req); | |
693 | ||
694 | cfq_del_crq_hash(crq); | |
695 | cfq_add_crq_hash(cfqd, crq); | |
696 | ||
b4878f24 | 697 | if (rq_rb_key(req) != crq->rb_key) { |
1da177e4 LT |
698 | struct cfq_queue *cfqq = crq->cfq_queue; |
699 | ||
700 | cfq_update_next_crq(crq); | |
701 | cfq_reposition_crq_rb(cfqq, crq); | |
702 | } | |
1da177e4 LT |
703 | } |
704 | ||
705 | static void | |
706 | cfq_merged_requests(request_queue_t *q, struct request *rq, | |
707 | struct request *next) | |
708 | { | |
1da177e4 LT |
709 | cfq_merged_request(q, rq); |
710 | ||
22e2c507 JA |
711 | /* |
712 | * reposition in fifo if next is older than rq | |
713 | */ | |
714 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
715 | time_before(next->start_time, rq->start_time)) | |
716 | list_move(&rq->queuelist, &next->queuelist); | |
717 | ||
b4878f24 | 718 | cfq_remove_request(next); |
22e2c507 JA |
719 | } |
720 | ||
721 | static inline void | |
722 | __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
723 | { | |
724 | if (cfqq) { | |
725 | /* | |
726 | * stop potential idle class queues waiting service | |
727 | */ | |
728 | del_timer(&cfqd->idle_class_timer); | |
729 | ||
730 | cfqq->slice_start = jiffies; | |
731 | cfqq->slice_end = 0; | |
732 | cfqq->slice_left = 0; | |
3b18152c JA |
733 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
734 | cfq_clear_cfqq_fifo_expire(cfqq); | |
22e2c507 JA |
735 | } |
736 | ||
737 | cfqd->active_queue = cfqq; | |
738 | } | |
739 | ||
7b14e3b5 JA |
740 | /* |
741 | * current cfqq expired its slice (or was too idle), select new one | |
742 | */ | |
743 | static void | |
744 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
745 | int preempted) | |
746 | { | |
747 | unsigned long now = jiffies; | |
748 | ||
749 | if (cfq_cfqq_wait_request(cfqq)) | |
750 | del_timer(&cfqd->idle_slice_timer); | |
751 | ||
752 | if (!preempted && !cfq_cfqq_dispatched(cfqq)) { | |
753 | cfqq->service_last = now; | |
754 | cfq_schedule_dispatch(cfqd); | |
755 | } | |
756 | ||
757 | cfq_clear_cfqq_must_dispatch(cfqq); | |
758 | cfq_clear_cfqq_wait_request(cfqq); | |
759 | ||
760 | /* | |
761 | * store what was left of this slice, if the queue idled out | |
762 | * or was preempted | |
763 | */ | |
764 | if (time_after(cfqq->slice_end, now)) | |
765 | cfqq->slice_left = cfqq->slice_end - now; | |
766 | else | |
767 | cfqq->slice_left = 0; | |
768 | ||
769 | if (cfq_cfqq_on_rr(cfqq)) | |
770 | cfq_resort_rr_list(cfqq, preempted); | |
771 | ||
772 | if (cfqq == cfqd->active_queue) | |
773 | cfqd->active_queue = NULL; | |
774 | ||
775 | if (cfqd->active_cic) { | |
776 | put_io_context(cfqd->active_cic->ioc); | |
777 | cfqd->active_cic = NULL; | |
778 | } | |
779 | ||
780 | cfqd->dispatch_slice = 0; | |
781 | } | |
782 | ||
783 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) | |
784 | { | |
785 | struct cfq_queue *cfqq = cfqd->active_queue; | |
786 | ||
787 | if (cfqq) | |
788 | __cfq_slice_expired(cfqd, cfqq, preempted); | |
789 | } | |
790 | ||
22e2c507 JA |
791 | /* |
792 | * 0 | |
793 | * 0,1 | |
794 | * 0,1,2 | |
795 | * 0,1,2,3 | |
796 | * 0,1,2,3,4 | |
797 | * 0,1,2,3,4,5 | |
798 | * 0,1,2,3,4,5,6 | |
799 | * 0,1,2,3,4,5,6,7 | |
800 | */ | |
801 | static int cfq_get_next_prio_level(struct cfq_data *cfqd) | |
802 | { | |
803 | int prio, wrap; | |
804 | ||
805 | prio = -1; | |
806 | wrap = 0; | |
807 | do { | |
808 | int p; | |
809 | ||
810 | for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { | |
811 | if (!list_empty(&cfqd->rr_list[p])) { | |
812 | prio = p; | |
813 | break; | |
814 | } | |
815 | } | |
816 | ||
817 | if (prio != -1) | |
818 | break; | |
819 | cfqd->cur_prio = 0; | |
820 | if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
821 | cfqd->cur_end_prio = 0; | |
822 | if (wrap) | |
823 | break; | |
824 | wrap = 1; | |
1da177e4 | 825 | } |
22e2c507 JA |
826 | } while (1); |
827 | ||
828 | if (unlikely(prio == -1)) | |
829 | return -1; | |
830 | ||
831 | BUG_ON(prio >= CFQ_PRIO_LISTS); | |
832 | ||
833 | list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); | |
834 | ||
835 | cfqd->cur_prio = prio + 1; | |
836 | if (cfqd->cur_prio > cfqd->cur_end_prio) { | |
837 | cfqd->cur_end_prio = cfqd->cur_prio; | |
838 | cfqd->cur_prio = 0; | |
839 | } | |
840 | if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
841 | cfqd->cur_prio = 0; | |
842 | cfqd->cur_end_prio = 0; | |
1da177e4 LT |
843 | } |
844 | ||
22e2c507 JA |
845 | return prio; |
846 | } | |
847 | ||
3b18152c | 848 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
22e2c507 | 849 | { |
7b14e3b5 | 850 | struct cfq_queue *cfqq = NULL; |
22e2c507 JA |
851 | |
852 | /* | |
853 | * if current list is non-empty, grab first entry. if it is empty, | |
854 | * get next prio level and grab first entry then if any are spliced | |
855 | */ | |
856 | if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) | |
857 | cfqq = list_entry_cfqq(cfqd->cur_rr.next); | |
858 | ||
859 | /* | |
860 | * if we have idle queues and no rt or be queues had pending | |
861 | * requests, either allow immediate service if the grace period | |
862 | * has passed or arm the idle grace timer | |
863 | */ | |
864 | if (!cfqq && !list_empty(&cfqd->idle_rr)) { | |
865 | unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
866 | ||
867 | if (time_after_eq(jiffies, end)) | |
868 | cfqq = list_entry_cfqq(cfqd->idle_rr.next); | |
869 | else | |
870 | mod_timer(&cfqd->idle_class_timer, end); | |
871 | } | |
872 | ||
873 | __cfq_set_active_queue(cfqd, cfqq); | |
3b18152c | 874 | return cfqq; |
22e2c507 JA |
875 | } |
876 | ||
22e2c507 JA |
877 | static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
878 | ||
879 | { | |
7b14e3b5 JA |
880 | unsigned long sl; |
881 | ||
22e2c507 JA |
882 | WARN_ON(!RB_EMPTY(&cfqq->sort_list)); |
883 | WARN_ON(cfqq != cfqd->active_queue); | |
884 | ||
885 | /* | |
886 | * idle is disabled, either manually or by past process history | |
887 | */ | |
888 | if (!cfqd->cfq_slice_idle) | |
889 | return 0; | |
3b18152c | 890 | if (!cfq_cfqq_idle_window(cfqq)) |
22e2c507 JA |
891 | return 0; |
892 | /* | |
893 | * task has exited, don't wait | |
894 | */ | |
895 | if (cfqd->active_cic && !cfqd->active_cic->ioc->task) | |
896 | return 0; | |
897 | ||
3b18152c JA |
898 | cfq_mark_cfqq_must_dispatch(cfqq); |
899 | cfq_mark_cfqq_wait_request(cfqq); | |
22e2c507 | 900 | |
7b14e3b5 JA |
901 | sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
902 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); | |
22e2c507 | 903 | return 1; |
1da177e4 LT |
904 | } |
905 | ||
b4878f24 | 906 | static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) |
1da177e4 LT |
907 | { |
908 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
909 | struct cfq_queue *cfqq = crq->cfq_queue; | |
22e2c507 JA |
910 | |
911 | cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); | |
b4878f24 | 912 | cfq_remove_request(crq->request); |
3b18152c | 913 | cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; |
b4878f24 | 914 | elv_dispatch_sort(q, crq->request); |
1da177e4 LT |
915 | } |
916 | ||
917 | /* | |
918 | * return expired entry, or NULL to just start from scratch in rbtree | |
919 | */ | |
920 | static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) | |
921 | { | |
922 | struct cfq_data *cfqd = cfqq->cfqd; | |
22e2c507 | 923 | struct request *rq; |
1da177e4 LT |
924 | struct cfq_rq *crq; |
925 | ||
3b18152c | 926 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 LT |
927 | return NULL; |
928 | ||
22e2c507 | 929 | if (!list_empty(&cfqq->fifo)) { |
3b18152c | 930 | int fifo = cfq_cfqq_class_sync(cfqq); |
1da177e4 | 931 | |
22e2c507 JA |
932 | crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); |
933 | rq = crq->request; | |
934 | if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { | |
3b18152c | 935 | cfq_mark_cfqq_fifo_expire(cfqq); |
22e2c507 JA |
936 | return crq; |
937 | } | |
1da177e4 LT |
938 | } |
939 | ||
940 | return NULL; | |
941 | } | |
942 | ||
943 | /* | |
3b18152c JA |
944 | * Scale schedule slice based on io priority. Use the sync time slice only |
945 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
946 | * io only, should not get full sync slice length. | |
1da177e4 | 947 | */ |
22e2c507 JA |
948 | static inline int |
949 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
950 | { | |
951 | const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; | |
952 | ||
953 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); | |
954 | ||
955 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); | |
956 | } | |
957 | ||
1da177e4 | 958 | static inline void |
22e2c507 | 959 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 960 | { |
22e2c507 JA |
961 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
962 | } | |
1da177e4 | 963 | |
22e2c507 JA |
964 | static inline int |
965 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
966 | { | |
967 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 968 | |
22e2c507 | 969 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 970 | |
22e2c507 | 971 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
972 | } |
973 | ||
22e2c507 JA |
974 | /* |
975 | * get next queue for service | |
976 | */ | |
1b5ed5e1 | 977 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 978 | { |
22e2c507 | 979 | unsigned long now = jiffies; |
1da177e4 | 980 | struct cfq_queue *cfqq; |
1da177e4 | 981 | |
22e2c507 JA |
982 | cfqq = cfqd->active_queue; |
983 | if (!cfqq) | |
984 | goto new_queue; | |
1da177e4 | 985 | |
22e2c507 JA |
986 | /* |
987 | * slice has expired | |
988 | */ | |
3b18152c JA |
989 | if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) |
990 | goto expire; | |
1da177e4 | 991 | |
22e2c507 JA |
992 | /* |
993 | * if queue has requests, dispatch one. if not, check if | |
994 | * enough slice is left to wait for one | |
995 | */ | |
996 | if (!RB_EMPTY(&cfqq->sort_list)) | |
997 | goto keep_queue; | |
1b5ed5e1 | 998 | else if (cfq_cfqq_class_sync(cfqq) && |
22e2c507 JA |
999 | time_before(now, cfqq->slice_end)) { |
1000 | if (cfq_arm_slice_timer(cfqd, cfqq)) | |
1001 | return NULL; | |
1002 | } | |
1003 | ||
3b18152c | 1004 | expire: |
22e2c507 | 1005 | cfq_slice_expired(cfqd, 0); |
3b18152c JA |
1006 | new_queue: |
1007 | cfqq = cfq_set_active_queue(cfqd); | |
22e2c507 | 1008 | keep_queue: |
3b18152c | 1009 | return cfqq; |
22e2c507 JA |
1010 | } |
1011 | ||
1012 | static int | |
1013 | __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1014 | int max_dispatch) | |
1015 | { | |
1016 | int dispatched = 0; | |
1017 | ||
1018 | BUG_ON(RB_EMPTY(&cfqq->sort_list)); | |
1019 | ||
1020 | do { | |
1021 | struct cfq_rq *crq; | |
1da177e4 LT |
1022 | |
1023 | /* | |
22e2c507 | 1024 | * follow expired path, else get first next available |
1da177e4 | 1025 | */ |
22e2c507 JA |
1026 | if ((crq = cfq_check_fifo(cfqq)) == NULL) |
1027 | crq = cfqq->next_crq; | |
1028 | ||
1029 | /* | |
1030 | * finally, insert request into driver dispatch list | |
1031 | */ | |
b4878f24 | 1032 | cfq_dispatch_insert(cfqd->queue, crq); |
1da177e4 | 1033 | |
22e2c507 JA |
1034 | cfqd->dispatch_slice++; |
1035 | dispatched++; | |
1da177e4 | 1036 | |
22e2c507 JA |
1037 | if (!cfqd->active_cic) { |
1038 | atomic_inc(&crq->io_context->ioc->refcount); | |
1039 | cfqd->active_cic = crq->io_context; | |
1040 | } | |
1da177e4 | 1041 | |
22e2c507 JA |
1042 | if (RB_EMPTY(&cfqq->sort_list)) |
1043 | break; | |
1044 | ||
1045 | } while (dispatched < max_dispatch); | |
1046 | ||
1047 | /* | |
1048 | * if slice end isn't set yet, set it. if at least one request was | |
1049 | * sync, use the sync time slice value | |
1050 | */ | |
1051 | if (!cfqq->slice_end) | |
1052 | cfq_set_prio_slice(cfqd, cfqq); | |
1053 | ||
1054 | /* | |
1055 | * expire an async queue immediately if it has used up its slice. idle | |
1056 | * queue always expire after 1 dispatch round. | |
1057 | */ | |
1058 | if ((!cfq_cfqq_sync(cfqq) && | |
1059 | cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
1060 | cfq_class_idle(cfqq)) | |
1061 | cfq_slice_expired(cfqd, 0); | |
1062 | ||
1063 | return dispatched; | |
1064 | } | |
1065 | ||
1b5ed5e1 TH |
1066 | static int |
1067 | cfq_forced_dispatch_cfqqs(struct list_head *list) | |
1068 | { | |
1069 | int dispatched = 0; | |
1070 | struct cfq_queue *cfqq, *next; | |
1071 | struct cfq_rq *crq; | |
1072 | ||
1073 | list_for_each_entry_safe(cfqq, next, list, cfq_list) { | |
1074 | while ((crq = cfqq->next_crq)) { | |
1075 | cfq_dispatch_insert(cfqq->cfqd->queue, crq); | |
1076 | dispatched++; | |
1077 | } | |
1078 | BUG_ON(!list_empty(&cfqq->fifo)); | |
1079 | } | |
1080 | return dispatched; | |
1081 | } | |
1082 | ||
1083 | static int | |
1084 | cfq_forced_dispatch(struct cfq_data *cfqd) | |
1085 | { | |
1086 | int i, dispatched = 0; | |
1087 | ||
1088 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
1089 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]); | |
1090 | ||
1091 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr); | |
1092 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr); | |
1093 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr); | |
1094 | ||
1095 | cfq_slice_expired(cfqd, 0); | |
1096 | ||
1097 | BUG_ON(cfqd->busy_queues); | |
1098 | ||
1099 | return dispatched; | |
1100 | } | |
1101 | ||
22e2c507 | 1102 | static int |
b4878f24 | 1103 | cfq_dispatch_requests(request_queue_t *q, int force) |
22e2c507 JA |
1104 | { |
1105 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1106 | struct cfq_queue *cfqq; | |
1107 | ||
1108 | if (!cfqd->busy_queues) | |
1109 | return 0; | |
1110 | ||
1b5ed5e1 TH |
1111 | if (unlikely(force)) |
1112 | return cfq_forced_dispatch(cfqd); | |
1113 | ||
1114 | cfqq = cfq_select_queue(cfqd); | |
22e2c507 | 1115 | if (cfqq) { |
b4878f24 JA |
1116 | int max_dispatch; |
1117 | ||
1118 | /* | |
1119 | * if idle window is disabled, allow queue buildup | |
1120 | */ | |
1121 | if (!cfq_cfqq_idle_window(cfqq) && | |
1122 | cfqd->rq_in_driver >= cfqd->cfq_max_depth) | |
1123 | return 0; | |
1124 | ||
3b18152c JA |
1125 | cfq_clear_cfqq_must_dispatch(cfqq); |
1126 | cfq_clear_cfqq_wait_request(cfqq); | |
22e2c507 JA |
1127 | del_timer(&cfqd->idle_slice_timer); |
1128 | ||
1b5ed5e1 TH |
1129 | max_dispatch = cfqd->cfq_quantum; |
1130 | if (cfq_class_idle(cfqq)) | |
1131 | max_dispatch = 1; | |
1da177e4 | 1132 | |
22e2c507 | 1133 | return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
1da177e4 LT |
1134 | } |
1135 | ||
22e2c507 | 1136 | return 0; |
1da177e4 LT |
1137 | } |
1138 | ||
1da177e4 LT |
1139 | /* |
1140 | * task holds one reference to the queue, dropped when task exits. each crq | |
1141 | * in-flight on this queue also holds a reference, dropped when crq is freed. | |
1142 | * | |
1143 | * queue lock must be held here. | |
1144 | */ | |
1145 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
1146 | { | |
22e2c507 JA |
1147 | struct cfq_data *cfqd = cfqq->cfqd; |
1148 | ||
1149 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
1150 | |
1151 | if (!atomic_dec_and_test(&cfqq->ref)) | |
1152 | return; | |
1153 | ||
1154 | BUG_ON(rb_first(&cfqq->sort_list)); | |
22e2c507 | 1155 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3b18152c | 1156 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 1157 | |
7b14e3b5 | 1158 | if (unlikely(cfqd->active_queue == cfqq)) |
3b18152c | 1159 | __cfq_slice_expired(cfqd, cfqq, 0); |
22e2c507 | 1160 | |
1da177e4 LT |
1161 | /* |
1162 | * it's on the empty list and still hashed | |
1163 | */ | |
1164 | list_del(&cfqq->cfq_list); | |
1165 | hlist_del(&cfqq->cfq_hash); | |
1166 | kmem_cache_free(cfq_pool, cfqq); | |
1167 | } | |
1168 | ||
1169 | static inline struct cfq_queue * | |
3b18152c JA |
1170 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, |
1171 | const int hashval) | |
1da177e4 LT |
1172 | { |
1173 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; | |
1174 | struct hlist_node *entry, *next; | |
1175 | ||
1176 | hlist_for_each_safe(entry, next, hash_list) { | |
1177 | struct cfq_queue *__cfqq = list_entry_qhash(entry); | |
b0a6916b | 1178 | const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio); |
1da177e4 | 1179 | |
3b18152c | 1180 | if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY)) |
1da177e4 LT |
1181 | return __cfqq; |
1182 | } | |
1183 | ||
1184 | return NULL; | |
1185 | } | |
1186 | ||
1187 | static struct cfq_queue * | |
3b18152c | 1188 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) |
1da177e4 | 1189 | { |
3b18152c | 1190 | return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); |
1da177e4 LT |
1191 | } |
1192 | ||
22e2c507 | 1193 | static void cfq_free_io_context(struct cfq_io_context *cic) |
1da177e4 | 1194 | { |
22e2c507 JA |
1195 | struct cfq_io_context *__cic; |
1196 | struct list_head *entry, *next; | |
334e94de | 1197 | int freed = 1; |
1da177e4 | 1198 | |
22e2c507 JA |
1199 | list_for_each_safe(entry, next, &cic->list) { |
1200 | __cic = list_entry(entry, struct cfq_io_context, list); | |
1201 | kmem_cache_free(cfq_ioc_pool, __cic); | |
334e94de | 1202 | freed++; |
1da177e4 LT |
1203 | } |
1204 | ||
22e2c507 | 1205 | kmem_cache_free(cfq_ioc_pool, cic); |
334e94de AV |
1206 | if (atomic_sub_and_test(freed, &ioc_count) && ioc_gone) |
1207 | complete(ioc_gone); | |
1da177e4 LT |
1208 | } |
1209 | ||
e17a9489 AV |
1210 | static void cfq_trim(struct io_context *ioc) |
1211 | { | |
1212 | ioc->set_ioprio = NULL; | |
1213 | if (ioc->cic) | |
1214 | cfq_free_io_context(ioc->cic); | |
1215 | } | |
1216 | ||
22e2c507 JA |
1217 | /* |
1218 | * Called with interrupts disabled | |
1219 | */ | |
1220 | static void cfq_exit_single_io_context(struct cfq_io_context *cic) | |
1da177e4 | 1221 | { |
478a82b0 | 1222 | struct cfq_data *cfqd = cic->key; |
d9ff4187 AV |
1223 | request_queue_t *q; |
1224 | ||
1225 | if (!cfqd) | |
1226 | return; | |
1227 | ||
1228 | q = cfqd->queue; | |
22e2c507 JA |
1229 | |
1230 | WARN_ON(!irqs_disabled()); | |
1231 | ||
1232 | spin_lock(q->queue_lock); | |
1233 | ||
12a05732 AV |
1234 | if (cic->cfqq[ASYNC]) { |
1235 | if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue)) | |
1236 | __cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0); | |
1237 | cfq_put_queue(cic->cfqq[ASYNC]); | |
1238 | cic->cfqq[ASYNC] = NULL; | |
1239 | } | |
1240 | ||
1241 | if (cic->cfqq[SYNC]) { | |
1242 | if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue)) | |
1243 | __cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0); | |
1244 | cfq_put_queue(cic->cfqq[SYNC]); | |
1245 | cic->cfqq[SYNC] = NULL; | |
1246 | } | |
22e2c507 | 1247 | |
478a82b0 | 1248 | cic->key = NULL; |
d9ff4187 | 1249 | list_del_init(&cic->queue_list); |
22e2c507 | 1250 | spin_unlock(q->queue_lock); |
1da177e4 LT |
1251 | } |
1252 | ||
1da177e4 LT |
1253 | static void cfq_exit_io_context(struct cfq_io_context *cic) |
1254 | { | |
22e2c507 JA |
1255 | struct cfq_io_context *__cic; |
1256 | struct list_head *entry; | |
1da177e4 LT |
1257 | unsigned long flags; |
1258 | ||
22e2c507 JA |
1259 | local_irq_save(flags); |
1260 | ||
1da177e4 LT |
1261 | /* |
1262 | * put the reference this task is holding to the various queues | |
1263 | */ | |
d9ff4187 | 1264 | read_lock(&cfq_exit_lock); |
22e2c507 | 1265 | list_for_each(entry, &cic->list) { |
1da177e4 | 1266 | __cic = list_entry(entry, struct cfq_io_context, list); |
22e2c507 | 1267 | cfq_exit_single_io_context(__cic); |
1da177e4 LT |
1268 | } |
1269 | ||
22e2c507 | 1270 | cfq_exit_single_io_context(cic); |
d9ff4187 | 1271 | read_unlock(&cfq_exit_lock); |
22e2c507 | 1272 | local_irq_restore(flags); |
1da177e4 LT |
1273 | } |
1274 | ||
22e2c507 | 1275 | static struct cfq_io_context * |
8267e268 | 1276 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1277 | { |
22e2c507 | 1278 | struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); |
1da177e4 LT |
1279 | |
1280 | if (cic) { | |
1da177e4 | 1281 | INIT_LIST_HEAD(&cic->list); |
12a05732 AV |
1282 | cic->cfqq[ASYNC] = NULL; |
1283 | cic->cfqq[SYNC] = NULL; | |
22e2c507 JA |
1284 | cic->key = NULL; |
1285 | cic->last_end_request = jiffies; | |
1286 | cic->ttime_total = 0; | |
1287 | cic->ttime_samples = 0; | |
1288 | cic->ttime_mean = 0; | |
1289 | cic->dtor = cfq_free_io_context; | |
1290 | cic->exit = cfq_exit_io_context; | |
d9ff4187 | 1291 | INIT_LIST_HEAD(&cic->queue_list); |
334e94de | 1292 | atomic_inc(&ioc_count); |
1da177e4 LT |
1293 | } |
1294 | ||
1295 | return cic; | |
1296 | } | |
1297 | ||
22e2c507 JA |
1298 | static void cfq_init_prio_data(struct cfq_queue *cfqq) |
1299 | { | |
1300 | struct task_struct *tsk = current; | |
1301 | int ioprio_class; | |
1302 | ||
3b18152c | 1303 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
1304 | return; |
1305 | ||
1306 | ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); | |
1307 | switch (ioprio_class) { | |
1308 | default: | |
1309 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
1310 | case IOPRIO_CLASS_NONE: | |
1311 | /* | |
1312 | * no prio set, place us in the middle of the BE classes | |
1313 | */ | |
1314 | cfqq->ioprio = task_nice_ioprio(tsk); | |
1315 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1316 | break; | |
1317 | case IOPRIO_CLASS_RT: | |
1318 | cfqq->ioprio = task_ioprio(tsk); | |
1319 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
1320 | break; | |
1321 | case IOPRIO_CLASS_BE: | |
1322 | cfqq->ioprio = task_ioprio(tsk); | |
1323 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1324 | break; | |
1325 | case IOPRIO_CLASS_IDLE: | |
1326 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
1327 | cfqq->ioprio = 7; | |
3b18152c | 1328 | cfq_clear_cfqq_idle_window(cfqq); |
22e2c507 JA |
1329 | break; |
1330 | } | |
1331 | ||
1332 | /* | |
1333 | * keep track of original prio settings in case we have to temporarily | |
1334 | * elevate the priority of this queue | |
1335 | */ | |
1336 | cfqq->org_ioprio = cfqq->ioprio; | |
1337 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
1338 | ||
3b18152c | 1339 | if (cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1340 | cfq_resort_rr_list(cfqq, 0); |
1341 | ||
3b18152c | 1342 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
1343 | } |
1344 | ||
478a82b0 | 1345 | static inline void changed_ioprio(struct cfq_io_context *cic) |
22e2c507 | 1346 | { |
478a82b0 AV |
1347 | struct cfq_data *cfqd = cic->key; |
1348 | struct cfq_queue *cfqq; | |
1349 | if (cfqd) { | |
22e2c507 | 1350 | spin_lock(cfqd->queue->queue_lock); |
12a05732 AV |
1351 | cfqq = cic->cfqq[ASYNC]; |
1352 | if (cfqq) { | |
6f325a13 AV |
1353 | struct cfq_queue *new_cfqq; |
1354 | new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, | |
1355 | cic->ioc->task, GFP_ATOMIC); | |
1356 | if (new_cfqq) { | |
1357 | cic->cfqq[ASYNC] = new_cfqq; | |
1358 | cfq_put_queue(cfqq); | |
1359 | } | |
12a05732 AV |
1360 | } |
1361 | cfqq = cic->cfqq[SYNC]; | |
478a82b0 AV |
1362 | if (cfqq) { |
1363 | cfq_mark_cfqq_prio_changed(cfqq); | |
1364 | cfq_init_prio_data(cfqq); | |
1365 | } | |
22e2c507 JA |
1366 | spin_unlock(cfqd->queue->queue_lock); |
1367 | } | |
1368 | } | |
1369 | ||
1370 | /* | |
1371 | * callback from sys_ioprio_set, irqs are disabled | |
1372 | */ | |
1373 | static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) | |
1374 | { | |
a6a0763a AV |
1375 | struct cfq_io_context *cic; |
1376 | ||
1377 | write_lock(&cfq_exit_lock); | |
1378 | ||
1379 | cic = ioc->cic; | |
22e2c507 | 1380 | |
478a82b0 | 1381 | changed_ioprio(cic); |
22e2c507 JA |
1382 | |
1383 | list_for_each_entry(cic, &cic->list, list) | |
478a82b0 | 1384 | changed_ioprio(cic); |
22e2c507 | 1385 | |
a6a0763a AV |
1386 | write_unlock(&cfq_exit_lock); |
1387 | ||
22e2c507 JA |
1388 | return 0; |
1389 | } | |
1390 | ||
1391 | static struct cfq_queue * | |
6f325a13 | 1392 | cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, |
8267e268 | 1393 | gfp_t gfp_mask) |
22e2c507 JA |
1394 | { |
1395 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); | |
1396 | struct cfq_queue *cfqq, *new_cfqq = NULL; | |
6f325a13 | 1397 | unsigned short ioprio; |
22e2c507 JA |
1398 | |
1399 | retry: | |
6f325a13 | 1400 | ioprio = tsk->ioprio; |
3b18152c | 1401 | cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); |
22e2c507 JA |
1402 | |
1403 | if (!cfqq) { | |
1404 | if (new_cfqq) { | |
1405 | cfqq = new_cfqq; | |
1406 | new_cfqq = NULL; | |
1407 | } else if (gfp_mask & __GFP_WAIT) { | |
1408 | spin_unlock_irq(cfqd->queue->queue_lock); | |
1409 | new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1410 | spin_lock_irq(cfqd->queue->queue_lock); | |
1411 | goto retry; | |
1412 | } else { | |
1413 | cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1414 | if (!cfqq) | |
1415 | goto out; | |
1416 | } | |
1417 | ||
1418 | memset(cfqq, 0, sizeof(*cfqq)); | |
1419 | ||
1420 | INIT_HLIST_NODE(&cfqq->cfq_hash); | |
1421 | INIT_LIST_HEAD(&cfqq->cfq_list); | |
1422 | RB_CLEAR_ROOT(&cfqq->sort_list); | |
1423 | INIT_LIST_HEAD(&cfqq->fifo); | |
1424 | ||
1425 | cfqq->key = key; | |
1426 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); | |
1427 | atomic_set(&cfqq->ref, 0); | |
1428 | cfqq->cfqd = cfqd; | |
22e2c507 JA |
1429 | cfqq->service_last = 0; |
1430 | /* | |
1431 | * set ->slice_left to allow preemption for a new process | |
1432 | */ | |
1433 | cfqq->slice_left = 2 * cfqd->cfq_slice_idle; | |
3b18152c JA |
1434 | cfq_mark_cfqq_idle_window(cfqq); |
1435 | cfq_mark_cfqq_prio_changed(cfqq); | |
1436 | cfq_init_prio_data(cfqq); | |
22e2c507 JA |
1437 | } |
1438 | ||
1439 | if (new_cfqq) | |
1440 | kmem_cache_free(cfq_pool, new_cfqq); | |
1441 | ||
1442 | atomic_inc(&cfqq->ref); | |
1443 | out: | |
1444 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); | |
1445 | return cfqq; | |
1446 | } | |
1447 | ||
1da177e4 LT |
1448 | /* |
1449 | * Setup general io context and cfq io context. There can be several cfq | |
1450 | * io contexts per general io context, if this process is doing io to more | |
1451 | * than one device managed by cfq. Note that caller is holding a reference to | |
1452 | * cfqq, so we don't need to worry about it disappearing | |
1453 | */ | |
1454 | static struct cfq_io_context * | |
8267e268 | 1455 | cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, gfp_t gfp_mask) |
1da177e4 | 1456 | { |
22e2c507 | 1457 | struct io_context *ioc = NULL; |
1da177e4 | 1458 | struct cfq_io_context *cic; |
1da177e4 | 1459 | |
22e2c507 | 1460 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 1461 | |
22e2c507 | 1462 | ioc = get_io_context(gfp_mask); |
1da177e4 LT |
1463 | if (!ioc) |
1464 | return NULL; | |
1465 | ||
d9ff4187 | 1466 | restart: |
1da177e4 | 1467 | if ((cic = ioc->cic) == NULL) { |
22e2c507 | 1468 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4 LT |
1469 | |
1470 | if (cic == NULL) | |
1471 | goto err; | |
1472 | ||
22e2c507 JA |
1473 | /* |
1474 | * manually increment generic io_context usage count, it | |
1475 | * cannot go away since we are already holding one ref to it | |
1476 | */ | |
1da177e4 | 1477 | cic->ioc = ioc; |
22e2c507 | 1478 | cic->key = cfqd; |
a6a0763a | 1479 | read_lock(&cfq_exit_lock); |
478a82b0 AV |
1480 | ioc->set_ioprio = cfq_ioc_set_ioprio; |
1481 | ioc->cic = cic; | |
d9ff4187 | 1482 | list_add(&cic->queue_list, &cfqd->cic_list); |
a6a0763a | 1483 | read_unlock(&cfq_exit_lock); |
1da177e4 LT |
1484 | } else { |
1485 | struct cfq_io_context *__cic; | |
1da177e4 LT |
1486 | |
1487 | /* | |
22e2c507 | 1488 | * the first cic on the list is actually the head itself |
1da177e4 | 1489 | */ |
22e2c507 | 1490 | if (cic->key == cfqd) |
1da177e4 LT |
1491 | goto out; |
1492 | ||
d9ff4187 AV |
1493 | if (unlikely(!cic->key)) { |
1494 | read_lock(&cfq_exit_lock); | |
1495 | if (list_empty(&cic->list)) | |
1496 | ioc->cic = NULL; | |
1497 | else | |
1498 | ioc->cic = list_entry(cic->list.next, | |
1499 | struct cfq_io_context, | |
1500 | list); | |
1501 | read_unlock(&cfq_exit_lock); | |
1502 | kmem_cache_free(cfq_ioc_pool, cic); | |
334e94de | 1503 | atomic_dec(&ioc_count); |
d9ff4187 AV |
1504 | goto restart; |
1505 | } | |
1506 | ||
1da177e4 LT |
1507 | /* |
1508 | * cic exists, check if we already are there. linear search | |
1509 | * should be ok here, the list will usually not be more than | |
1510 | * 1 or a few entries long | |
1511 | */ | |
1da177e4 LT |
1512 | list_for_each_entry(__cic, &cic->list, list) { |
1513 | /* | |
1514 | * this process is already holding a reference to | |
1515 | * this queue, so no need to get one more | |
1516 | */ | |
22e2c507 | 1517 | if (__cic->key == cfqd) { |
1da177e4 | 1518 | cic = __cic; |
1da177e4 LT |
1519 | goto out; |
1520 | } | |
d9ff4187 AV |
1521 | if (unlikely(!__cic->key)) { |
1522 | read_lock(&cfq_exit_lock); | |
1523 | list_del(&__cic->list); | |
1524 | read_unlock(&cfq_exit_lock); | |
1525 | kmem_cache_free(cfq_ioc_pool, __cic); | |
334e94de | 1526 | atomic_dec(&ioc_count); |
d9ff4187 AV |
1527 | goto restart; |
1528 | } | |
1da177e4 | 1529 | } |
1da177e4 LT |
1530 | |
1531 | /* | |
1532 | * nope, process doesn't have a cic assoicated with this | |
1533 | * cfqq yet. get a new one and add to list | |
1534 | */ | |
22e2c507 | 1535 | __cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4 LT |
1536 | if (__cic == NULL) |
1537 | goto err; | |
1538 | ||
1539 | __cic->ioc = ioc; | |
22e2c507 | 1540 | __cic->key = cfqd; |
a6a0763a | 1541 | read_lock(&cfq_exit_lock); |
1da177e4 | 1542 | list_add(&__cic->list, &cic->list); |
d9ff4187 | 1543 | list_add(&__cic->queue_list, &cfqd->cic_list); |
a6a0763a | 1544 | read_unlock(&cfq_exit_lock); |
1da177e4 | 1545 | cic = __cic; |
1da177e4 LT |
1546 | } |
1547 | ||
1548 | out: | |
1da177e4 LT |
1549 | return cic; |
1550 | err: | |
1551 | put_io_context(ioc); | |
1552 | return NULL; | |
1553 | } | |
1554 | ||
22e2c507 JA |
1555 | static void |
1556 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 1557 | { |
22e2c507 | 1558 | unsigned long elapsed, ttime; |
1da177e4 | 1559 | |
22e2c507 JA |
1560 | /* |
1561 | * if this context already has stuff queued, thinktime is from | |
1562 | * last queue not last end | |
1563 | */ | |
1564 | #if 0 | |
1565 | if (time_after(cic->last_end_request, cic->last_queue)) | |
1566 | elapsed = jiffies - cic->last_end_request; | |
1567 | else | |
1568 | elapsed = jiffies - cic->last_queue; | |
1569 | #else | |
1570 | elapsed = jiffies - cic->last_end_request; | |
1571 | #endif | |
1da177e4 | 1572 | |
22e2c507 | 1573 | ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
db3b5848 | 1574 | |
22e2c507 JA |
1575 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
1576 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
1577 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
1578 | } | |
1da177e4 | 1579 | |
22e2c507 | 1580 | #define sample_valid(samples) ((samples) > 80) |
1da177e4 | 1581 | |
22e2c507 JA |
1582 | /* |
1583 | * Disable idle window if the process thinks too long or seeks so much that | |
1584 | * it doesn't matter | |
1585 | */ | |
1586 | static void | |
1587 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1588 | struct cfq_io_context *cic) | |
1589 | { | |
3b18152c | 1590 | int enable_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 1591 | |
22e2c507 JA |
1592 | if (!cic->ioc->task || !cfqd->cfq_slice_idle) |
1593 | enable_idle = 0; | |
1594 | else if (sample_valid(cic->ttime_samples)) { | |
1595 | if (cic->ttime_mean > cfqd->cfq_slice_idle) | |
1596 | enable_idle = 0; | |
1597 | else | |
1598 | enable_idle = 1; | |
1da177e4 LT |
1599 | } |
1600 | ||
3b18152c JA |
1601 | if (enable_idle) |
1602 | cfq_mark_cfqq_idle_window(cfqq); | |
1603 | else | |
1604 | cfq_clear_cfqq_idle_window(cfqq); | |
22e2c507 | 1605 | } |
1da177e4 | 1606 | |
22e2c507 JA |
1607 | |
1608 | /* | |
1609 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
1610 | * no or if we aren't sure, a 1 will cause a preempt. | |
1611 | */ | |
1612 | static int | |
1613 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, | |
1614 | struct cfq_rq *crq) | |
1615 | { | |
1616 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1617 | ||
1618 | if (cfq_class_idle(new_cfqq)) | |
1619 | return 0; | |
1620 | ||
1621 | if (!cfqq) | |
1622 | return 1; | |
1623 | ||
1624 | if (cfq_class_idle(cfqq)) | |
1625 | return 1; | |
3b18152c | 1626 | if (!cfq_cfqq_wait_request(new_cfqq)) |
22e2c507 JA |
1627 | return 0; |
1628 | /* | |
1629 | * if it doesn't have slice left, forget it | |
1630 | */ | |
1631 | if (new_cfqq->slice_left < cfqd->cfq_slice_idle) | |
1632 | return 0; | |
3b18152c | 1633 | if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq)) |
22e2c507 JA |
1634 | return 1; |
1635 | ||
1636 | return 0; | |
1637 | } | |
1638 | ||
1639 | /* | |
1640 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
1641 | * let it have half of its nominal slice. | |
1642 | */ | |
1643 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1644 | { | |
1645 | struct cfq_queue *__cfqq, *next; | |
1646 | ||
1647 | list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) | |
1648 | cfq_resort_rr_list(__cfqq, 1); | |
1649 | ||
1650 | if (!cfqq->slice_left) | |
1651 | cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; | |
1652 | ||
1653 | cfqq->slice_end = cfqq->slice_left + jiffies; | |
3b18152c | 1654 | __cfq_slice_expired(cfqd, cfqq, 1); |
22e2c507 JA |
1655 | __cfq_set_active_queue(cfqd, cfqq); |
1656 | } | |
1657 | ||
1658 | /* | |
1659 | * should really be a ll_rw_blk.c helper | |
1660 | */ | |
1661 | static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1662 | { | |
1663 | request_queue_t *q = cfqd->queue; | |
1664 | ||
1665 | if (!blk_queue_plugged(q)) | |
1666 | q->request_fn(q); | |
1667 | else | |
1668 | __generic_unplug_device(q); | |
1669 | } | |
1670 | ||
1671 | /* | |
1672 | * Called when a new fs request (crq) is added (to cfqq). Check if there's | |
1673 | * something we should do about it | |
1674 | */ | |
1675 | static void | |
1676 | cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1677 | struct cfq_rq *crq) | |
1678 | { | |
9c2c38a1 | 1679 | struct cfq_io_context *cic; |
22e2c507 JA |
1680 | |
1681 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
1682 | ||
9c2c38a1 JA |
1683 | /* |
1684 | * we never wait for an async request and we don't allow preemption | |
1685 | * of an async request. so just return early | |
1686 | */ | |
1687 | if (!cfq_crq_is_sync(crq)) | |
1688 | return; | |
22e2c507 | 1689 | |
9c2c38a1 | 1690 | cic = crq->io_context; |
22e2c507 | 1691 | |
9c2c38a1 JA |
1692 | cfq_update_io_thinktime(cfqd, cic); |
1693 | cfq_update_idle_window(cfqd, cfqq, cic); | |
1694 | ||
1695 | cic->last_queue = jiffies; | |
22e2c507 JA |
1696 | |
1697 | if (cfqq == cfqd->active_queue) { | |
1698 | /* | |
1699 | * if we are waiting for a request for this queue, let it rip | |
1700 | * immediately and flag that we must not expire this queue | |
1701 | * just now | |
1702 | */ | |
3b18152c JA |
1703 | if (cfq_cfqq_wait_request(cfqq)) { |
1704 | cfq_mark_cfqq_must_dispatch(cfqq); | |
22e2c507 JA |
1705 | del_timer(&cfqd->idle_slice_timer); |
1706 | cfq_start_queueing(cfqd, cfqq); | |
1707 | } | |
1708 | } else if (cfq_should_preempt(cfqd, cfqq, crq)) { | |
1709 | /* | |
1710 | * not the active queue - expire current slice if it is | |
1711 | * idle and has expired it's mean thinktime or this new queue | |
1712 | * has some old slice time left and is of higher priority | |
1713 | */ | |
1714 | cfq_preempt_queue(cfqd, cfqq); | |
3b18152c | 1715 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
1716 | cfq_start_queueing(cfqd, cfqq); |
1717 | } | |
1da177e4 LT |
1718 | } |
1719 | ||
b4878f24 | 1720 | static void cfq_insert_request(request_queue_t *q, struct request *rq) |
1da177e4 | 1721 | { |
b4878f24 | 1722 | struct cfq_data *cfqd = q->elevator->elevator_data; |
22e2c507 JA |
1723 | struct cfq_rq *crq = RQ_DATA(rq); |
1724 | struct cfq_queue *cfqq = crq->cfq_queue; | |
1725 | ||
1726 | cfq_init_prio_data(cfqq); | |
1da177e4 LT |
1727 | |
1728 | cfq_add_crq_rb(crq); | |
1da177e4 | 1729 | |
22e2c507 JA |
1730 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
1731 | ||
98b11471 | 1732 | if (rq_mergeable(rq)) |
22e2c507 JA |
1733 | cfq_add_crq_hash(cfqd, crq); |
1734 | ||
22e2c507 | 1735 | cfq_crq_enqueued(cfqd, cfqq, crq); |
1da177e4 LT |
1736 | } |
1737 | ||
1da177e4 LT |
1738 | static void cfq_completed_request(request_queue_t *q, struct request *rq) |
1739 | { | |
1740 | struct cfq_rq *crq = RQ_DATA(rq); | |
b4878f24 JA |
1741 | struct cfq_queue *cfqq = crq->cfq_queue; |
1742 | struct cfq_data *cfqd = cfqq->cfqd; | |
1743 | const int sync = cfq_crq_is_sync(crq); | |
1744 | unsigned long now; | |
1da177e4 | 1745 | |
b4878f24 | 1746 | now = jiffies; |
1da177e4 | 1747 | |
b4878f24 JA |
1748 | WARN_ON(!cfqd->rq_in_driver); |
1749 | WARN_ON(!cfqq->on_dispatch[sync]); | |
1750 | cfqd->rq_in_driver--; | |
1751 | cfqq->on_dispatch[sync]--; | |
1da177e4 | 1752 | |
b4878f24 JA |
1753 | if (!cfq_class_idle(cfqq)) |
1754 | cfqd->last_end_request = now; | |
3b18152c | 1755 | |
b4878f24 JA |
1756 | if (!cfq_cfqq_dispatched(cfqq)) { |
1757 | if (cfq_cfqq_on_rr(cfqq)) { | |
1758 | cfqq->service_last = now; | |
1759 | cfq_resort_rr_list(cfqq, 0); | |
1760 | } | |
7b14e3b5 | 1761 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
1762 | } |
1763 | ||
b4878f24 JA |
1764 | if (cfq_crq_is_sync(crq)) |
1765 | crq->io_context->last_end_request = now; | |
1da177e4 LT |
1766 | } |
1767 | ||
1768 | static struct request * | |
1769 | cfq_former_request(request_queue_t *q, struct request *rq) | |
1770 | { | |
1771 | struct cfq_rq *crq = RQ_DATA(rq); | |
1772 | struct rb_node *rbprev = rb_prev(&crq->rb_node); | |
1773 | ||
1774 | if (rbprev) | |
1775 | return rb_entry_crq(rbprev)->request; | |
1776 | ||
1777 | return NULL; | |
1778 | } | |
1779 | ||
1780 | static struct request * | |
1781 | cfq_latter_request(request_queue_t *q, struct request *rq) | |
1782 | { | |
1783 | struct cfq_rq *crq = RQ_DATA(rq); | |
1784 | struct rb_node *rbnext = rb_next(&crq->rb_node); | |
1785 | ||
1786 | if (rbnext) | |
1787 | return rb_entry_crq(rbnext)->request; | |
1788 | ||
1789 | return NULL; | |
1790 | } | |
1791 | ||
22e2c507 JA |
1792 | /* |
1793 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
1794 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
1795 | */ | |
1796 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 1797 | { |
22e2c507 JA |
1798 | const int ioprio_class = cfqq->ioprio_class; |
1799 | const int ioprio = cfqq->ioprio; | |
1da177e4 | 1800 | |
22e2c507 JA |
1801 | if (has_fs_excl()) { |
1802 | /* | |
1803 | * boost idle prio on transactions that would lock out other | |
1804 | * users of the filesystem | |
1805 | */ | |
1806 | if (cfq_class_idle(cfqq)) | |
1807 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1808 | if (cfqq->ioprio > IOPRIO_NORM) | |
1809 | cfqq->ioprio = IOPRIO_NORM; | |
1810 | } else { | |
1811 | /* | |
1812 | * check if we need to unboost the queue | |
1813 | */ | |
1814 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) | |
1815 | cfqq->ioprio_class = cfqq->org_ioprio_class; | |
1816 | if (cfqq->ioprio != cfqq->org_ioprio) | |
1817 | cfqq->ioprio = cfqq->org_ioprio; | |
1818 | } | |
1da177e4 | 1819 | |
22e2c507 JA |
1820 | /* |
1821 | * refile between round-robin lists if we moved the priority class | |
1822 | */ | |
1823 | if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && | |
3b18152c | 1824 | cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1825 | cfq_resort_rr_list(cfqq, 0); |
1826 | } | |
1da177e4 | 1827 | |
22e2c507 JA |
1828 | static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
1829 | { | |
1830 | if (rw == READ || process_sync(task)) | |
1831 | return task->pid; | |
1da177e4 | 1832 | |
22e2c507 JA |
1833 | return CFQ_KEY_ASYNC; |
1834 | } | |
1da177e4 | 1835 | |
22e2c507 JA |
1836 | static inline int |
1837 | __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1838 | struct task_struct *task, int rw) | |
1839 | { | |
3b18152c JA |
1840 | #if 1 |
1841 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && | |
99f95e52 | 1842 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1843 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1844 | return ELV_MQUEUE_MUST; |
3b18152c | 1845 | } |
1da177e4 | 1846 | |
22e2c507 | 1847 | return ELV_MQUEUE_MAY; |
3b18152c | 1848 | #else |
22e2c507 JA |
1849 | if (!cfqq || task->flags & PF_MEMALLOC) |
1850 | return ELV_MQUEUE_MAY; | |
3b18152c JA |
1851 | if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) { |
1852 | if (cfq_cfqq_wait_request(cfqq)) | |
22e2c507 | 1853 | return ELV_MQUEUE_MUST; |
1da177e4 | 1854 | |
22e2c507 JA |
1855 | /* |
1856 | * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we | |
1857 | * can quickly flood the queue with writes from a single task | |
1858 | */ | |
99f95e52 | 1859 | if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1860 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1861 | return ELV_MQUEUE_MUST; |
1da177e4 | 1862 | } |
22e2c507 JA |
1863 | |
1864 | return ELV_MQUEUE_MAY; | |
1da177e4 | 1865 | } |
22e2c507 JA |
1866 | if (cfq_class_idle(cfqq)) |
1867 | return ELV_MQUEUE_NO; | |
1868 | if (cfqq->allocated[rw] >= cfqd->max_queued) { | |
1869 | struct io_context *ioc = get_io_context(GFP_ATOMIC); | |
1870 | int ret = ELV_MQUEUE_NO; | |
1da177e4 | 1871 | |
22e2c507 JA |
1872 | if (ioc && ioc->nr_batch_requests) |
1873 | ret = ELV_MQUEUE_MAY; | |
1874 | ||
1875 | put_io_context(ioc); | |
1876 | return ret; | |
1877 | } | |
1878 | ||
1879 | return ELV_MQUEUE_MAY; | |
1880 | #endif | |
1881 | } | |
1882 | ||
1883 | static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) | |
1884 | { | |
1885 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1886 | struct task_struct *tsk = current; | |
1887 | struct cfq_queue *cfqq; | |
1888 | ||
1889 | /* | |
1890 | * don't force setup of a queue from here, as a call to may_queue | |
1891 | * does not necessarily imply that a request actually will be queued. | |
1892 | * so just lookup a possibly existing queue, or return 'may queue' | |
1893 | * if that fails | |
1894 | */ | |
3b18152c | 1895 | cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); |
22e2c507 JA |
1896 | if (cfqq) { |
1897 | cfq_init_prio_data(cfqq); | |
1898 | cfq_prio_boost(cfqq); | |
1899 | ||
1900 | return __cfq_may_queue(cfqd, cfqq, tsk, rw); | |
1901 | } | |
1902 | ||
1903 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
1904 | } |
1905 | ||
1906 | static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) | |
1907 | { | |
22e2c507 | 1908 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1da177e4 | 1909 | struct request_list *rl = &q->rq; |
1da177e4 | 1910 | |
22e2c507 JA |
1911 | if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) { |
1912 | smp_mb(); | |
1913 | if (waitqueue_active(&rl->wait[READ])) | |
1914 | wake_up(&rl->wait[READ]); | |
1915 | } | |
1916 | ||
1917 | if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) { | |
1918 | smp_mb(); | |
1919 | if (waitqueue_active(&rl->wait[WRITE])) | |
1920 | wake_up(&rl->wait[WRITE]); | |
1921 | } | |
1da177e4 LT |
1922 | } |
1923 | ||
1924 | /* | |
1925 | * queue lock held here | |
1926 | */ | |
1927 | static void cfq_put_request(request_queue_t *q, struct request *rq) | |
1928 | { | |
1929 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1930 | struct cfq_rq *crq = RQ_DATA(rq); | |
1931 | ||
1932 | if (crq) { | |
1933 | struct cfq_queue *cfqq = crq->cfq_queue; | |
22e2c507 | 1934 | const int rw = rq_data_dir(rq); |
1da177e4 | 1935 | |
22e2c507 JA |
1936 | BUG_ON(!cfqq->allocated[rw]); |
1937 | cfqq->allocated[rw]--; | |
1da177e4 | 1938 | |
22e2c507 | 1939 | put_io_context(crq->io_context->ioc); |
1da177e4 LT |
1940 | |
1941 | mempool_free(crq, cfqd->crq_pool); | |
1942 | rq->elevator_private = NULL; | |
1943 | ||
1da177e4 LT |
1944 | cfq_check_waiters(q, cfqq); |
1945 | cfq_put_queue(cfqq); | |
1946 | } | |
1947 | } | |
1948 | ||
1949 | /* | |
22e2c507 | 1950 | * Allocate cfq data structures associated with this request. |
1da177e4 | 1951 | */ |
22e2c507 JA |
1952 | static int |
1953 | cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, | |
8267e268 | 1954 | gfp_t gfp_mask) |
1da177e4 LT |
1955 | { |
1956 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3b18152c | 1957 | struct task_struct *tsk = current; |
1da177e4 LT |
1958 | struct cfq_io_context *cic; |
1959 | const int rw = rq_data_dir(rq); | |
3b18152c | 1960 | pid_t key = cfq_queue_pid(tsk, rw); |
22e2c507 | 1961 | struct cfq_queue *cfqq; |
1da177e4 LT |
1962 | struct cfq_rq *crq; |
1963 | unsigned long flags; | |
12a05732 | 1964 | int is_sync = key != CFQ_KEY_ASYNC; |
1da177e4 LT |
1965 | |
1966 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
1967 | ||
3b18152c | 1968 | cic = cfq_get_io_context(cfqd, key, gfp_mask); |
22e2c507 | 1969 | |
1da177e4 LT |
1970 | spin_lock_irqsave(q->queue_lock, flags); |
1971 | ||
22e2c507 JA |
1972 | if (!cic) |
1973 | goto queue_fail; | |
1974 | ||
12a05732 | 1975 | if (!cic->cfqq[is_sync]) { |
6f325a13 | 1976 | cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask); |
22e2c507 JA |
1977 | if (!cfqq) |
1978 | goto queue_fail; | |
1da177e4 | 1979 | |
12a05732 | 1980 | cic->cfqq[is_sync] = cfqq; |
22e2c507 | 1981 | } else |
12a05732 | 1982 | cfqq = cic->cfqq[is_sync]; |
1da177e4 LT |
1983 | |
1984 | cfqq->allocated[rw]++; | |
3b18152c | 1985 | cfq_clear_cfqq_must_alloc(cfqq); |
22e2c507 JA |
1986 | cfqd->rq_starved = 0; |
1987 | atomic_inc(&cfqq->ref); | |
1da177e4 LT |
1988 | spin_unlock_irqrestore(q->queue_lock, flags); |
1989 | ||
1da177e4 LT |
1990 | crq = mempool_alloc(cfqd->crq_pool, gfp_mask); |
1991 | if (crq) { | |
1992 | RB_CLEAR(&crq->rb_node); | |
1993 | crq->rb_key = 0; | |
1994 | crq->request = rq; | |
1995 | INIT_HLIST_NODE(&crq->hash); | |
1996 | crq->cfq_queue = cfqq; | |
1997 | crq->io_context = cic; | |
3b18152c | 1998 | |
12a05732 | 1999 | if (is_sync) |
3b18152c JA |
2000 | cfq_mark_crq_is_sync(crq); |
2001 | else | |
2002 | cfq_clear_crq_is_sync(crq); | |
2003 | ||
1da177e4 | 2004 | rq->elevator_private = crq; |
1da177e4 LT |
2005 | return 0; |
2006 | } | |
2007 | ||
1da177e4 LT |
2008 | spin_lock_irqsave(q->queue_lock, flags); |
2009 | cfqq->allocated[rw]--; | |
22e2c507 | 2010 | if (!(cfqq->allocated[0] + cfqq->allocated[1])) |
3b18152c | 2011 | cfq_mark_cfqq_must_alloc(cfqq); |
1da177e4 | 2012 | cfq_put_queue(cfqq); |
22e2c507 JA |
2013 | queue_fail: |
2014 | if (cic) | |
2015 | put_io_context(cic->ioc); | |
2016 | /* | |
2017 | * mark us rq allocation starved. we need to kickstart the process | |
2018 | * ourselves if there are no pending requests that can do it for us. | |
2019 | * that would be an extremely rare OOM situation | |
2020 | */ | |
2021 | cfqd->rq_starved = 1; | |
3b18152c | 2022 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
2023 | spin_unlock_irqrestore(q->queue_lock, flags); |
2024 | return 1; | |
2025 | } | |
2026 | ||
22e2c507 JA |
2027 | static void cfq_kick_queue(void *data) |
2028 | { | |
2029 | request_queue_t *q = data; | |
2030 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2031 | unsigned long flags; | |
2032 | ||
2033 | spin_lock_irqsave(q->queue_lock, flags); | |
2034 | ||
2035 | if (cfqd->rq_starved) { | |
2036 | struct request_list *rl = &q->rq; | |
2037 | ||
2038 | /* | |
2039 | * we aren't guaranteed to get a request after this, but we | |
2040 | * have to be opportunistic | |
2041 | */ | |
2042 | smp_mb(); | |
2043 | if (waitqueue_active(&rl->wait[READ])) | |
2044 | wake_up(&rl->wait[READ]); | |
2045 | if (waitqueue_active(&rl->wait[WRITE])) | |
2046 | wake_up(&rl->wait[WRITE]); | |
2047 | } | |
2048 | ||
2049 | blk_remove_plug(q); | |
2050 | q->request_fn(q); | |
2051 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2052 | } | |
2053 | ||
2054 | /* | |
2055 | * Timer running if the active_queue is currently idling inside its time slice | |
2056 | */ | |
2057 | static void cfq_idle_slice_timer(unsigned long data) | |
2058 | { | |
2059 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2060 | struct cfq_queue *cfqq; | |
2061 | unsigned long flags; | |
2062 | ||
2063 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2064 | ||
2065 | if ((cfqq = cfqd->active_queue) != NULL) { | |
2066 | unsigned long now = jiffies; | |
2067 | ||
2068 | /* | |
2069 | * expired | |
2070 | */ | |
2071 | if (time_after(now, cfqq->slice_end)) | |
2072 | goto expire; | |
2073 | ||
2074 | /* | |
2075 | * only expire and reinvoke request handler, if there are | |
2076 | * other queues with pending requests | |
2077 | */ | |
b4878f24 | 2078 | if (!cfqd->busy_queues) { |
22e2c507 JA |
2079 | cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end); |
2080 | add_timer(&cfqd->idle_slice_timer); | |
2081 | goto out_cont; | |
2082 | } | |
2083 | ||
2084 | /* | |
2085 | * not expired and it has a request pending, let it dispatch | |
2086 | */ | |
2087 | if (!RB_EMPTY(&cfqq->sort_list)) { | |
3b18152c | 2088 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
2089 | goto out_kick; |
2090 | } | |
2091 | } | |
2092 | expire: | |
2093 | cfq_slice_expired(cfqd, 0); | |
2094 | out_kick: | |
3b18152c | 2095 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2096 | out_cont: |
2097 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2098 | } | |
2099 | ||
2100 | /* | |
2101 | * Timer running if an idle class queue is waiting for service | |
2102 | */ | |
2103 | static void cfq_idle_class_timer(unsigned long data) | |
2104 | { | |
2105 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2106 | unsigned long flags, end; | |
2107 | ||
2108 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2109 | ||
2110 | /* | |
2111 | * race with a non-idle queue, reset timer | |
2112 | */ | |
2113 | end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
2114 | if (!time_after_eq(jiffies, end)) { | |
2115 | cfqd->idle_class_timer.expires = end; | |
2116 | add_timer(&cfqd->idle_class_timer); | |
2117 | } else | |
3b18152c | 2118 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2119 | |
2120 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2121 | } | |
2122 | ||
3b18152c JA |
2123 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
2124 | { | |
2125 | del_timer_sync(&cfqd->idle_slice_timer); | |
2126 | del_timer_sync(&cfqd->idle_class_timer); | |
2127 | blk_sync_queue(cfqd->queue); | |
2128 | } | |
22e2c507 | 2129 | |
1da177e4 LT |
2130 | static void cfq_exit_queue(elevator_t *e) |
2131 | { | |
22e2c507 | 2132 | struct cfq_data *cfqd = e->elevator_data; |
d9ff4187 | 2133 | request_queue_t *q = cfqd->queue; |
22e2c507 | 2134 | |
3b18152c | 2135 | cfq_shutdown_timer_wq(cfqd); |
d9ff4187 AV |
2136 | write_lock(&cfq_exit_lock); |
2137 | spin_lock_irq(q->queue_lock); | |
2138 | if (cfqd->active_queue) | |
2139 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); | |
2140 | while(!list_empty(&cfqd->cic_list)) { | |
2141 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, | |
2142 | struct cfq_io_context, | |
2143 | queue_list); | |
2144 | if (cic->cfqq[ASYNC]) { | |
2145 | cfq_put_queue(cic->cfqq[ASYNC]); | |
2146 | cic->cfqq[ASYNC] = NULL; | |
2147 | } | |
2148 | if (cic->cfqq[SYNC]) { | |
2149 | cfq_put_queue(cic->cfqq[SYNC]); | |
2150 | cic->cfqq[SYNC] = NULL; | |
2151 | } | |
2152 | cic->key = NULL; | |
2153 | list_del_init(&cic->queue_list); | |
2154 | } | |
2155 | spin_unlock_irq(q->queue_lock); | |
2156 | write_unlock(&cfq_exit_lock); | |
a90d742e AV |
2157 | |
2158 | cfq_shutdown_timer_wq(cfqd); | |
2159 | ||
2160 | mempool_destroy(cfqd->crq_pool); | |
2161 | kfree(cfqd->crq_hash); | |
2162 | kfree(cfqd->cfq_hash); | |
2163 | kfree(cfqd); | |
1da177e4 LT |
2164 | } |
2165 | ||
2166 | static int cfq_init_queue(request_queue_t *q, elevator_t *e) | |
2167 | { | |
2168 | struct cfq_data *cfqd; | |
2169 | int i; | |
2170 | ||
2171 | cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); | |
2172 | if (!cfqd) | |
2173 | return -ENOMEM; | |
2174 | ||
2175 | memset(cfqd, 0, sizeof(*cfqd)); | |
22e2c507 JA |
2176 | |
2177 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
2178 | INIT_LIST_HEAD(&cfqd->rr_list[i]); | |
2179 | ||
2180 | INIT_LIST_HEAD(&cfqd->busy_rr); | |
2181 | INIT_LIST_HEAD(&cfqd->cur_rr); | |
2182 | INIT_LIST_HEAD(&cfqd->idle_rr); | |
1da177e4 | 2183 | INIT_LIST_HEAD(&cfqd->empty_list); |
d9ff4187 | 2184 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 LT |
2185 | |
2186 | cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); | |
2187 | if (!cfqd->crq_hash) | |
2188 | goto out_crqhash; | |
2189 | ||
2190 | cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); | |
2191 | if (!cfqd->cfq_hash) | |
2192 | goto out_cfqhash; | |
2193 | ||
2194 | cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool); | |
2195 | if (!cfqd->crq_pool) | |
2196 | goto out_crqpool; | |
2197 | ||
2198 | for (i = 0; i < CFQ_MHASH_ENTRIES; i++) | |
2199 | INIT_HLIST_HEAD(&cfqd->crq_hash[i]); | |
2200 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) | |
2201 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); | |
2202 | ||
2203 | e->elevator_data = cfqd; | |
2204 | ||
2205 | cfqd->queue = q; | |
1da177e4 | 2206 | |
22e2c507 | 2207 | cfqd->max_queued = q->nr_requests / 4; |
1da177e4 | 2208 | q->nr_batching = cfq_queued; |
22e2c507 JA |
2209 | |
2210 | init_timer(&cfqd->idle_slice_timer); | |
2211 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
2212 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
2213 | ||
2214 | init_timer(&cfqd->idle_class_timer); | |
2215 | cfqd->idle_class_timer.function = cfq_idle_class_timer; | |
2216 | cfqd->idle_class_timer.data = (unsigned long) cfqd; | |
2217 | ||
2218 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); | |
2219 | ||
1da177e4 LT |
2220 | cfqd->cfq_queued = cfq_queued; |
2221 | cfqd->cfq_quantum = cfq_quantum; | |
22e2c507 JA |
2222 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
2223 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
2224 | cfqd->cfq_back_max = cfq_back_max; |
2225 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
2226 | cfqd->cfq_slice[0] = cfq_slice_async; |
2227 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
2228 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
2229 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
2230 | cfqd->cfq_max_depth = cfq_max_depth; | |
3b18152c | 2231 | |
1da177e4 LT |
2232 | return 0; |
2233 | out_crqpool: | |
2234 | kfree(cfqd->cfq_hash); | |
2235 | out_cfqhash: | |
2236 | kfree(cfqd->crq_hash); | |
2237 | out_crqhash: | |
2238 | kfree(cfqd); | |
2239 | return -ENOMEM; | |
2240 | } | |
2241 | ||
2242 | static void cfq_slab_kill(void) | |
2243 | { | |
2244 | if (crq_pool) | |
2245 | kmem_cache_destroy(crq_pool); | |
2246 | if (cfq_pool) | |
2247 | kmem_cache_destroy(cfq_pool); | |
2248 | if (cfq_ioc_pool) | |
2249 | kmem_cache_destroy(cfq_ioc_pool); | |
2250 | } | |
2251 | ||
2252 | static int __init cfq_slab_setup(void) | |
2253 | { | |
2254 | crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, | |
2255 | NULL, NULL); | |
2256 | if (!crq_pool) | |
2257 | goto fail; | |
2258 | ||
2259 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, | |
2260 | NULL, NULL); | |
2261 | if (!cfq_pool) | |
2262 | goto fail; | |
2263 | ||
2264 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", | |
2265 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); | |
2266 | if (!cfq_ioc_pool) | |
2267 | goto fail; | |
2268 | ||
2269 | return 0; | |
2270 | fail: | |
2271 | cfq_slab_kill(); | |
2272 | return -ENOMEM; | |
2273 | } | |
2274 | ||
1da177e4 LT |
2275 | /* |
2276 | * sysfs parts below --> | |
2277 | */ | |
2278 | struct cfq_fs_entry { | |
2279 | struct attribute attr; | |
2280 | ssize_t (*show)(struct cfq_data *, char *); | |
2281 | ssize_t (*store)(struct cfq_data *, const char *, size_t); | |
2282 | }; | |
2283 | ||
2284 | static ssize_t | |
2285 | cfq_var_show(unsigned int var, char *page) | |
2286 | { | |
2287 | return sprintf(page, "%d\n", var); | |
2288 | } | |
2289 | ||
2290 | static ssize_t | |
2291 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
2292 | { | |
2293 | char *p = (char *) page; | |
2294 | ||
2295 | *var = simple_strtoul(p, &p, 10); | |
2296 | return count; | |
2297 | } | |
2298 | ||
1da177e4 LT |
2299 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
2300 | static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \ | |
2301 | { \ | |
2302 | unsigned int __data = __VAR; \ | |
2303 | if (__CONV) \ | |
2304 | __data = jiffies_to_msecs(__data); \ | |
2305 | return cfq_var_show(__data, (page)); \ | |
2306 | } | |
2307 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
2308 | SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); | |
22e2c507 JA |
2309 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
2310 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
1da177e4 LT |
2311 | SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); |
2312 | SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
2313 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
2314 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
2315 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
2316 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
2317 | SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0); | |
1da177e4 LT |
2318 | #undef SHOW_FUNCTION |
2319 | ||
2320 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
2321 | static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \ | |
2322 | { \ | |
2323 | unsigned int __data; \ | |
2324 | int ret = cfq_var_store(&__data, (page), count); \ | |
2325 | if (__data < (MIN)) \ | |
2326 | __data = (MIN); \ | |
2327 | else if (__data > (MAX)) \ | |
2328 | __data = (MAX); \ | |
2329 | if (__CONV) \ | |
2330 | *(__PTR) = msecs_to_jiffies(__data); \ | |
2331 | else \ | |
2332 | *(__PTR) = __data; \ | |
2333 | return ret; \ | |
2334 | } | |
2335 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
2336 | STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); | |
22e2c507 JA |
2337 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); |
2338 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); | |
1da177e4 LT |
2339 | STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
2340 | STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); | |
22e2c507 JA |
2341 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
2342 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
2343 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
2344 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); | |
2345 | STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0); | |
1da177e4 LT |
2346 | #undef STORE_FUNCTION |
2347 | ||
2348 | static struct cfq_fs_entry cfq_quantum_entry = { | |
2349 | .attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR }, | |
2350 | .show = cfq_quantum_show, | |
2351 | .store = cfq_quantum_store, | |
2352 | }; | |
2353 | static struct cfq_fs_entry cfq_queued_entry = { | |
2354 | .attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR }, | |
2355 | .show = cfq_queued_show, | |
2356 | .store = cfq_queued_store, | |
2357 | }; | |
22e2c507 | 2358 | static struct cfq_fs_entry cfq_fifo_expire_sync_entry = { |
1da177e4 | 2359 | .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, |
22e2c507 JA |
2360 | .show = cfq_fifo_expire_sync_show, |
2361 | .store = cfq_fifo_expire_sync_store, | |
1da177e4 | 2362 | }; |
22e2c507 | 2363 | static struct cfq_fs_entry cfq_fifo_expire_async_entry = { |
1da177e4 | 2364 | .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, |
22e2c507 JA |
2365 | .show = cfq_fifo_expire_async_show, |
2366 | .store = cfq_fifo_expire_async_store, | |
1da177e4 LT |
2367 | }; |
2368 | static struct cfq_fs_entry cfq_back_max_entry = { | |
2369 | .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR }, | |
2370 | .show = cfq_back_max_show, | |
2371 | .store = cfq_back_max_store, | |
2372 | }; | |
2373 | static struct cfq_fs_entry cfq_back_penalty_entry = { | |
2374 | .attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR }, | |
2375 | .show = cfq_back_penalty_show, | |
2376 | .store = cfq_back_penalty_store, | |
2377 | }; | |
22e2c507 JA |
2378 | static struct cfq_fs_entry cfq_slice_sync_entry = { |
2379 | .attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR }, | |
2380 | .show = cfq_slice_sync_show, | |
2381 | .store = cfq_slice_sync_store, | |
1da177e4 | 2382 | }; |
22e2c507 JA |
2383 | static struct cfq_fs_entry cfq_slice_async_entry = { |
2384 | .attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR }, | |
2385 | .show = cfq_slice_async_show, | |
2386 | .store = cfq_slice_async_store, | |
2387 | }; | |
2388 | static struct cfq_fs_entry cfq_slice_async_rq_entry = { | |
2389 | .attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR }, | |
2390 | .show = cfq_slice_async_rq_show, | |
2391 | .store = cfq_slice_async_rq_store, | |
2392 | }; | |
2393 | static struct cfq_fs_entry cfq_slice_idle_entry = { | |
2394 | .attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR }, | |
2395 | .show = cfq_slice_idle_show, | |
2396 | .store = cfq_slice_idle_store, | |
2397 | }; | |
2398 | static struct cfq_fs_entry cfq_max_depth_entry = { | |
2399 | .attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR }, | |
2400 | .show = cfq_max_depth_show, | |
2401 | .store = cfq_max_depth_store, | |
1da177e4 | 2402 | }; |
3b18152c | 2403 | |
1da177e4 LT |
2404 | static struct attribute *default_attrs[] = { |
2405 | &cfq_quantum_entry.attr, | |
2406 | &cfq_queued_entry.attr, | |
22e2c507 JA |
2407 | &cfq_fifo_expire_sync_entry.attr, |
2408 | &cfq_fifo_expire_async_entry.attr, | |
1da177e4 LT |
2409 | &cfq_back_max_entry.attr, |
2410 | &cfq_back_penalty_entry.attr, | |
22e2c507 JA |
2411 | &cfq_slice_sync_entry.attr, |
2412 | &cfq_slice_async_entry.attr, | |
2413 | &cfq_slice_async_rq_entry.attr, | |
2414 | &cfq_slice_idle_entry.attr, | |
2415 | &cfq_max_depth_entry.attr, | |
1da177e4 LT |
2416 | NULL, |
2417 | }; | |
2418 | ||
2419 | #define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr) | |
2420 | ||
2421 | static ssize_t | |
2422 | cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page) | |
2423 | { | |
2424 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
2425 | struct cfq_fs_entry *entry = to_cfq(attr); | |
2426 | ||
2427 | if (!entry->show) | |
6c1852a0 | 2428 | return -EIO; |
1da177e4 LT |
2429 | |
2430 | return entry->show(e->elevator_data, page); | |
2431 | } | |
2432 | ||
2433 | static ssize_t | |
2434 | cfq_attr_store(struct kobject *kobj, struct attribute *attr, | |
2435 | const char *page, size_t length) | |
2436 | { | |
2437 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
2438 | struct cfq_fs_entry *entry = to_cfq(attr); | |
2439 | ||
2440 | if (!entry->store) | |
6c1852a0 | 2441 | return -EIO; |
1da177e4 LT |
2442 | |
2443 | return entry->store(e->elevator_data, page, length); | |
2444 | } | |
2445 | ||
2446 | static struct sysfs_ops cfq_sysfs_ops = { | |
2447 | .show = cfq_attr_show, | |
2448 | .store = cfq_attr_store, | |
2449 | }; | |
2450 | ||
2451 | static struct kobj_type cfq_ktype = { | |
2452 | .sysfs_ops = &cfq_sysfs_ops, | |
2453 | .default_attrs = default_attrs, | |
2454 | }; | |
2455 | ||
2456 | static struct elevator_type iosched_cfq = { | |
2457 | .ops = { | |
2458 | .elevator_merge_fn = cfq_merge, | |
2459 | .elevator_merged_fn = cfq_merged_request, | |
2460 | .elevator_merge_req_fn = cfq_merged_requests, | |
b4878f24 | 2461 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 2462 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 2463 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
2464 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
2465 | .elevator_queue_empty_fn = cfq_queue_empty, | |
2466 | .elevator_completed_req_fn = cfq_completed_request, | |
2467 | .elevator_former_req_fn = cfq_former_request, | |
2468 | .elevator_latter_req_fn = cfq_latter_request, | |
2469 | .elevator_set_req_fn = cfq_set_request, | |
2470 | .elevator_put_req_fn = cfq_put_request, | |
2471 | .elevator_may_queue_fn = cfq_may_queue, | |
2472 | .elevator_init_fn = cfq_init_queue, | |
2473 | .elevator_exit_fn = cfq_exit_queue, | |
e17a9489 | 2474 | .trim = cfq_trim, |
1da177e4 LT |
2475 | }, |
2476 | .elevator_ktype = &cfq_ktype, | |
2477 | .elevator_name = "cfq", | |
2478 | .elevator_owner = THIS_MODULE, | |
2479 | }; | |
2480 | ||
2481 | static int __init cfq_init(void) | |
2482 | { | |
2483 | int ret; | |
2484 | ||
22e2c507 JA |
2485 | /* |
2486 | * could be 0 on HZ < 1000 setups | |
2487 | */ | |
2488 | if (!cfq_slice_async) | |
2489 | cfq_slice_async = 1; | |
2490 | if (!cfq_slice_idle) | |
2491 | cfq_slice_idle = 1; | |
2492 | ||
1da177e4 LT |
2493 | if (cfq_slab_setup()) |
2494 | return -ENOMEM; | |
2495 | ||
2496 | ret = elv_register(&iosched_cfq); | |
22e2c507 JA |
2497 | if (ret) |
2498 | cfq_slab_kill(); | |
1da177e4 | 2499 | |
1da177e4 LT |
2500 | return ret; |
2501 | } | |
2502 | ||
2503 | static void __exit cfq_exit(void) | |
2504 | { | |
334e94de | 2505 | DECLARE_COMPLETION(all_gone); |
1da177e4 | 2506 | elv_unregister(&iosched_cfq); |
334e94de AV |
2507 | ioc_gone = &all_gone; |
2508 | barrier(); | |
2509 | if (atomic_read(&ioc_count)) | |
2510 | complete(ioc_gone); | |
2511 | synchronize_rcu(); | |
83521d3e | 2512 | cfq_slab_kill(); |
1da177e4 LT |
2513 | } |
2514 | ||
2515 | module_init(cfq_init); | |
2516 | module_exit(cfq_exit); | |
2517 | ||
2518 | MODULE_AUTHOR("Jens Axboe"); | |
2519 | MODULE_LICENSE("GPL"); | |
2520 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |