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 | */ | |
9 | #include <linux/kernel.h> | |
10 | #include <linux/fs.h> | |
11 | #include <linux/blkdev.h> | |
12 | #include <linux/elevator.h> | |
13 | #include <linux/bio.h> | |
14 | #include <linux/config.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/compiler.h> | |
19 | #include <linux/hash.h> | |
20 | #include <linux/rbtree.h> | |
21 | #include <linux/mempool.h> | |
22e2c507 JA |
22 | #include <linux/ioprio.h> |
23 | #include <linux/writeback.h> | |
1da177e4 LT |
24 | |
25 | /* | |
26 | * tunables | |
27 | */ | |
64100099 AV |
28 | static const int cfq_quantum = 4; /* max queue in one round of service */ |
29 | static const int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ | |
30 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; | |
31 | static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ | |
32 | static const int cfq_back_penalty = 2; /* penalty of a backwards seek */ | |
1da177e4 | 33 | |
64100099 | 34 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 35 | static int cfq_slice_async = HZ / 25; |
64100099 | 36 | static const int cfq_slice_async_rq = 2; |
3b18152c | 37 | static int cfq_slice_idle = HZ / 100; |
22e2c507 JA |
38 | |
39 | #define CFQ_IDLE_GRACE (HZ / 10) | |
40 | #define CFQ_SLICE_SCALE (5) | |
41 | ||
42 | #define CFQ_KEY_ASYNC (0) | |
3b18152c | 43 | #define CFQ_KEY_ANY (0xffff) |
22e2c507 JA |
44 | |
45 | /* | |
46 | * disable queueing at the driver/hardware level | |
47 | */ | |
64100099 | 48 | static const int cfq_max_depth = 2; |
22e2c507 | 49 | |
a6a0763a AV |
50 | static DEFINE_RWLOCK(cfq_exit_lock); |
51 | ||
1da177e4 LT |
52 | /* |
53 | * for the hash of cfqq inside the cfqd | |
54 | */ | |
55 | #define CFQ_QHASH_SHIFT 6 | |
56 | #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) | |
57 | #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) | |
58 | ||
59 | /* | |
60 | * for the hash of crq inside the cfqq | |
61 | */ | |
62 | #define CFQ_MHASH_SHIFT 6 | |
63 | #define CFQ_MHASH_BLOCK(sec) ((sec) >> 3) | |
64 | #define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT) | |
65 | #define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT) | |
66 | #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) | |
67 | #define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash) | |
68 | ||
69 | #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) | |
22e2c507 | 70 | #define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
1da177e4 LT |
71 | |
72 | #define RQ_DATA(rq) (rq)->elevator_private | |
73 | ||
74 | /* | |
75 | * rb-tree defines | |
76 | */ | |
77 | #define RB_NONE (2) | |
78 | #define RB_EMPTY(node) ((node)->rb_node == NULL) | |
79 | #define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE | |
80 | #define RB_CLEAR(node) do { \ | |
81 | (node)->rb_parent = NULL; \ | |
82 | RB_CLEAR_COLOR((node)); \ | |
83 | (node)->rb_right = NULL; \ | |
84 | (node)->rb_left = NULL; \ | |
85 | } while (0) | |
86 | #define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL) | |
1da177e4 LT |
87 | #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) |
88 | #define rq_rb_key(rq) (rq)->sector | |
89 | ||
1da177e4 LT |
90 | static kmem_cache_t *crq_pool; |
91 | static kmem_cache_t *cfq_pool; | |
92 | static kmem_cache_t *cfq_ioc_pool; | |
93 | ||
334e94de AV |
94 | static atomic_t ioc_count = ATOMIC_INIT(0); |
95 | static struct completion *ioc_gone; | |
96 | ||
22e2c507 JA |
97 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
98 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
99 | #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) | |
100 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) | |
101 | ||
3b18152c JA |
102 | #define ASYNC (0) |
103 | #define SYNC (1) | |
104 | ||
105 | #define cfq_cfqq_dispatched(cfqq) \ | |
106 | ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) | |
107 | ||
108 | #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) | |
109 | ||
110 | #define cfq_cfqq_sync(cfqq) \ | |
111 | (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) | |
22e2c507 JA |
112 | |
113 | /* | |
114 | * Per block device queue structure | |
115 | */ | |
1da177e4 | 116 | struct cfq_data { |
22e2c507 JA |
117 | atomic_t ref; |
118 | request_queue_t *queue; | |
119 | ||
120 | /* | |
121 | * rr list of queues with requests and the count of them | |
122 | */ | |
123 | struct list_head rr_list[CFQ_PRIO_LISTS]; | |
124 | struct list_head busy_rr; | |
125 | struct list_head cur_rr; | |
126 | struct list_head idle_rr; | |
127 | unsigned int busy_queues; | |
128 | ||
129 | /* | |
130 | * non-ordered list of empty cfqq's | |
131 | */ | |
1da177e4 LT |
132 | struct list_head empty_list; |
133 | ||
22e2c507 JA |
134 | /* |
135 | * cfqq lookup hash | |
136 | */ | |
1da177e4 | 137 | struct hlist_head *cfq_hash; |
1da177e4 | 138 | |
22e2c507 JA |
139 | /* |
140 | * global crq hash for all queues | |
141 | */ | |
142 | struct hlist_head *crq_hash; | |
1da177e4 LT |
143 | |
144 | unsigned int max_queued; | |
145 | ||
22e2c507 | 146 | mempool_t *crq_pool; |
1da177e4 | 147 | |
22e2c507 | 148 | int rq_in_driver; |
1da177e4 | 149 | |
22e2c507 JA |
150 | /* |
151 | * schedule slice state info | |
152 | */ | |
153 | /* | |
154 | * idle window management | |
155 | */ | |
156 | struct timer_list idle_slice_timer; | |
157 | struct work_struct unplug_work; | |
1da177e4 | 158 | |
22e2c507 JA |
159 | struct cfq_queue *active_queue; |
160 | struct cfq_io_context *active_cic; | |
161 | int cur_prio, cur_end_prio; | |
162 | unsigned int dispatch_slice; | |
163 | ||
164 | struct timer_list idle_class_timer; | |
1da177e4 LT |
165 | |
166 | sector_t last_sector; | |
22e2c507 | 167 | unsigned long last_end_request; |
1da177e4 | 168 | |
22e2c507 | 169 | unsigned int rq_starved; |
1da177e4 LT |
170 | |
171 | /* | |
172 | * tunables, see top of file | |
173 | */ | |
174 | unsigned int cfq_quantum; | |
175 | unsigned int cfq_queued; | |
22e2c507 | 176 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
177 | unsigned int cfq_back_penalty; |
178 | unsigned int cfq_back_max; | |
22e2c507 JA |
179 | unsigned int cfq_slice[2]; |
180 | unsigned int cfq_slice_async_rq; | |
181 | unsigned int cfq_slice_idle; | |
182 | unsigned int cfq_max_depth; | |
d9ff4187 AV |
183 | |
184 | struct list_head cic_list; | |
1da177e4 LT |
185 | }; |
186 | ||
22e2c507 JA |
187 | /* |
188 | * Per process-grouping structure | |
189 | */ | |
1da177e4 LT |
190 | struct cfq_queue { |
191 | /* reference count */ | |
192 | atomic_t ref; | |
193 | /* parent cfq_data */ | |
194 | struct cfq_data *cfqd; | |
22e2c507 | 195 | /* cfqq lookup hash */ |
1da177e4 LT |
196 | struct hlist_node cfq_hash; |
197 | /* hash key */ | |
22e2c507 | 198 | unsigned int key; |
1da177e4 LT |
199 | /* on either rr or empty list of cfqd */ |
200 | struct list_head cfq_list; | |
201 | /* sorted list of pending requests */ | |
202 | struct rb_root sort_list; | |
203 | /* if fifo isn't expired, next request to serve */ | |
204 | struct cfq_rq *next_crq; | |
205 | /* requests queued in sort_list */ | |
206 | int queued[2]; | |
207 | /* currently allocated requests */ | |
208 | int allocated[2]; | |
209 | /* fifo list of requests in sort_list */ | |
22e2c507 | 210 | struct list_head fifo; |
1da177e4 | 211 | |
22e2c507 JA |
212 | unsigned long slice_start; |
213 | unsigned long slice_end; | |
214 | unsigned long slice_left; | |
215 | unsigned long service_last; | |
1da177e4 | 216 | |
3b18152c JA |
217 | /* number of requests that are on the dispatch list */ |
218 | int on_dispatch[2]; | |
22e2c507 JA |
219 | |
220 | /* io prio of this group */ | |
221 | unsigned short ioprio, org_ioprio; | |
222 | unsigned short ioprio_class, org_ioprio_class; | |
223 | ||
3b18152c JA |
224 | /* various state flags, see below */ |
225 | unsigned int flags; | |
1da177e4 LT |
226 | }; |
227 | ||
228 | struct cfq_rq { | |
229 | struct rb_node rb_node; | |
230 | sector_t rb_key; | |
231 | struct request *request; | |
232 | struct hlist_node hash; | |
233 | ||
234 | struct cfq_queue *cfq_queue; | |
235 | struct cfq_io_context *io_context; | |
236 | ||
3b18152c | 237 | unsigned int crq_flags; |
1da177e4 LT |
238 | }; |
239 | ||
3b18152c JA |
240 | enum cfqq_state_flags { |
241 | CFQ_CFQQ_FLAG_on_rr = 0, | |
242 | CFQ_CFQQ_FLAG_wait_request, | |
243 | CFQ_CFQQ_FLAG_must_alloc, | |
244 | CFQ_CFQQ_FLAG_must_alloc_slice, | |
245 | CFQ_CFQQ_FLAG_must_dispatch, | |
246 | CFQ_CFQQ_FLAG_fifo_expire, | |
247 | CFQ_CFQQ_FLAG_idle_window, | |
248 | CFQ_CFQQ_FLAG_prio_changed, | |
3b18152c JA |
249 | }; |
250 | ||
251 | #define CFQ_CFQQ_FNS(name) \ | |
252 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
253 | { \ | |
254 | cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ | |
255 | } \ | |
256 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
257 | { \ | |
258 | cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ | |
259 | } \ | |
260 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
261 | { \ | |
262 | return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ | |
263 | } | |
264 | ||
265 | CFQ_CFQQ_FNS(on_rr); | |
266 | CFQ_CFQQ_FNS(wait_request); | |
267 | CFQ_CFQQ_FNS(must_alloc); | |
268 | CFQ_CFQQ_FNS(must_alloc_slice); | |
269 | CFQ_CFQQ_FNS(must_dispatch); | |
270 | CFQ_CFQQ_FNS(fifo_expire); | |
271 | CFQ_CFQQ_FNS(idle_window); | |
272 | CFQ_CFQQ_FNS(prio_changed); | |
3b18152c JA |
273 | #undef CFQ_CFQQ_FNS |
274 | ||
275 | enum cfq_rq_state_flags { | |
b4878f24 | 276 | CFQ_CRQ_FLAG_is_sync = 0, |
3b18152c JA |
277 | }; |
278 | ||
279 | #define CFQ_CRQ_FNS(name) \ | |
280 | static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \ | |
281 | { \ | |
282 | crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \ | |
283 | } \ | |
284 | static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \ | |
285 | { \ | |
286 | crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \ | |
287 | } \ | |
288 | static inline int cfq_crq_##name(const struct cfq_rq *crq) \ | |
289 | { \ | |
290 | return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \ | |
291 | } | |
292 | ||
3b18152c | 293 | CFQ_CRQ_FNS(is_sync); |
3b18152c JA |
294 | #undef CFQ_CRQ_FNS |
295 | ||
296 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); | |
b4878f24 | 297 | static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); |
1da177e4 LT |
298 | static void cfq_put_cfqd(struct cfq_data *cfqd); |
299 | ||
22e2c507 | 300 | #define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) |
1da177e4 LT |
301 | |
302 | /* | |
303 | * lots of deadline iosched dupes, can be abstracted later... | |
304 | */ | |
305 | static inline void cfq_del_crq_hash(struct cfq_rq *crq) | |
306 | { | |
307 | hlist_del_init(&crq->hash); | |
308 | } | |
309 | ||
1da177e4 LT |
310 | static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) |
311 | { | |
312 | const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); | |
313 | ||
1da177e4 LT |
314 | hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); |
315 | } | |
316 | ||
317 | static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) | |
318 | { | |
319 | struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)]; | |
320 | struct hlist_node *entry, *next; | |
321 | ||
322 | hlist_for_each_safe(entry, next, hash_list) { | |
323 | struct cfq_rq *crq = list_entry_hash(entry); | |
324 | struct request *__rq = crq->request; | |
325 | ||
1da177e4 LT |
326 | if (!rq_mergeable(__rq)) { |
327 | cfq_del_crq_hash(crq); | |
328 | continue; | |
329 | } | |
330 | ||
331 | if (rq_hash_key(__rq) == offset) | |
332 | return __rq; | |
333 | } | |
334 | ||
335 | return NULL; | |
336 | } | |
337 | ||
99f95e52 AM |
338 | /* |
339 | * scheduler run of queue, if there are requests pending and no one in the | |
340 | * driver that will restart queueing | |
341 | */ | |
342 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) | |
343 | { | |
7b14e3b5 | 344 | if (cfqd->busy_queues) |
99f95e52 AM |
345 | kblockd_schedule_work(&cfqd->unplug_work); |
346 | } | |
347 | ||
348 | static int cfq_queue_empty(request_queue_t *q) | |
349 | { | |
350 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
351 | ||
b4878f24 | 352 | return !cfqd->busy_queues; |
99f95e52 AM |
353 | } |
354 | ||
1da177e4 LT |
355 | /* |
356 | * Lifted from AS - choose which of crq1 and crq2 that is best served now. | |
357 | * We choose the request that is closest to the head right now. Distance | |
358 | * behind the head are penalized and only allowed to a certain extent. | |
359 | */ | |
360 | static struct cfq_rq * | |
361 | cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) | |
362 | { | |
363 | sector_t last, s1, s2, d1 = 0, d2 = 0; | |
364 | int r1_wrap = 0, r2_wrap = 0; /* requests are behind the disk head */ | |
365 | unsigned long back_max; | |
366 | ||
367 | if (crq1 == NULL || crq1 == crq2) | |
368 | return crq2; | |
369 | if (crq2 == NULL) | |
370 | return crq1; | |
9c2c38a1 | 371 | |
9c2c38a1 JA |
372 | if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2)) |
373 | return crq1; | |
374 | else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1)) | |
22e2c507 | 375 | return crq2; |
1da177e4 LT |
376 | |
377 | s1 = crq1->request->sector; | |
378 | s2 = crq2->request->sector; | |
379 | ||
380 | last = cfqd->last_sector; | |
381 | ||
1da177e4 LT |
382 | /* |
383 | * by definition, 1KiB is 2 sectors | |
384 | */ | |
385 | back_max = cfqd->cfq_back_max * 2; | |
386 | ||
387 | /* | |
388 | * Strict one way elevator _except_ in the case where we allow | |
389 | * short backward seeks which are biased as twice the cost of a | |
390 | * similar forward seek. | |
391 | */ | |
392 | if (s1 >= last) | |
393 | d1 = s1 - last; | |
394 | else if (s1 + back_max >= last) | |
395 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
396 | else | |
397 | r1_wrap = 1; | |
398 | ||
399 | if (s2 >= last) | |
400 | d2 = s2 - last; | |
401 | else if (s2 + back_max >= last) | |
402 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
403 | else | |
404 | r2_wrap = 1; | |
405 | ||
406 | /* Found required data */ | |
407 | if (!r1_wrap && r2_wrap) | |
408 | return crq1; | |
409 | else if (!r2_wrap && r1_wrap) | |
410 | return crq2; | |
411 | else if (r1_wrap && r2_wrap) { | |
412 | /* both behind the head */ | |
413 | if (s1 <= s2) | |
414 | return crq1; | |
415 | else | |
416 | return crq2; | |
417 | } | |
418 | ||
419 | /* Both requests in front of the head */ | |
420 | if (d1 < d2) | |
421 | return crq1; | |
422 | else if (d2 < d1) | |
423 | return crq2; | |
424 | else { | |
425 | if (s1 >= s2) | |
426 | return crq1; | |
427 | else | |
428 | return crq2; | |
429 | } | |
430 | } | |
431 | ||
432 | /* | |
433 | * would be nice to take fifo expire time into account as well | |
434 | */ | |
435 | static struct cfq_rq * | |
436 | cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
437 | struct cfq_rq *last) | |
438 | { | |
439 | struct cfq_rq *crq_next = NULL, *crq_prev = NULL; | |
440 | struct rb_node *rbnext, *rbprev; | |
441 | ||
b4878f24 | 442 | if (!(rbnext = rb_next(&last->rb_node))) { |
1da177e4 | 443 | rbnext = rb_first(&cfqq->sort_list); |
22e2c507 JA |
444 | if (rbnext == &last->rb_node) |
445 | rbnext = NULL; | |
446 | } | |
1da177e4 LT |
447 | |
448 | rbprev = rb_prev(&last->rb_node); | |
449 | ||
450 | if (rbprev) | |
451 | crq_prev = rb_entry_crq(rbprev); | |
452 | if (rbnext) | |
453 | crq_next = rb_entry_crq(rbnext); | |
454 | ||
455 | return cfq_choose_req(cfqd, crq_next, crq_prev); | |
456 | } | |
457 | ||
458 | static void cfq_update_next_crq(struct cfq_rq *crq) | |
459 | { | |
460 | struct cfq_queue *cfqq = crq->cfq_queue; | |
461 | ||
462 | if (cfqq->next_crq == crq) | |
463 | cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); | |
464 | } | |
465 | ||
22e2c507 | 466 | static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
1da177e4 | 467 | { |
22e2c507 JA |
468 | struct cfq_data *cfqd = cfqq->cfqd; |
469 | struct list_head *list, *entry; | |
1da177e4 | 470 | |
3b18152c | 471 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 472 | |
22e2c507 | 473 | list_del(&cfqq->cfq_list); |
1da177e4 | 474 | |
22e2c507 JA |
475 | if (cfq_class_rt(cfqq)) |
476 | list = &cfqd->cur_rr; | |
477 | else if (cfq_class_idle(cfqq)) | |
478 | list = &cfqd->idle_rr; | |
479 | else { | |
480 | /* | |
481 | * if cfqq has requests in flight, don't allow it to be | |
482 | * found in cfq_set_active_queue before it has finished them. | |
483 | * this is done to increase fairness between a process that | |
484 | * has lots of io pending vs one that only generates one | |
485 | * sporadically or synchronously | |
486 | */ | |
3b18152c | 487 | if (cfq_cfqq_dispatched(cfqq)) |
22e2c507 JA |
488 | list = &cfqd->busy_rr; |
489 | else | |
490 | list = &cfqd->rr_list[cfqq->ioprio]; | |
1da177e4 LT |
491 | } |
492 | ||
22e2c507 JA |
493 | /* |
494 | * if queue was preempted, just add to front to be fair. busy_rr | |
495 | * isn't sorted. | |
496 | */ | |
497 | if (preempted || list == &cfqd->busy_rr) { | |
498 | list_add(&cfqq->cfq_list, list); | |
1da177e4 | 499 | return; |
22e2c507 | 500 | } |
1da177e4 LT |
501 | |
502 | /* | |
22e2c507 | 503 | * sort by when queue was last serviced |
1da177e4 | 504 | */ |
22e2c507 JA |
505 | entry = list; |
506 | while ((entry = entry->prev) != list) { | |
1da177e4 LT |
507 | struct cfq_queue *__cfqq = list_entry_cfqq(entry); |
508 | ||
22e2c507 JA |
509 | if (!__cfqq->service_last) |
510 | break; | |
511 | if (time_before(__cfqq->service_last, cfqq->service_last)) | |
1da177e4 | 512 | break; |
1da177e4 LT |
513 | } |
514 | ||
515 | list_add(&cfqq->cfq_list, entry); | |
516 | } | |
517 | ||
518 | /* | |
519 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 520 | * the pending list according to last request service |
1da177e4 LT |
521 | */ |
522 | static inline void | |
b4878f24 | 523 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 524 | { |
3b18152c JA |
525 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
526 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
527 | cfqd->busy_queues++; |
528 | ||
b4878f24 | 529 | cfq_resort_rr_list(cfqq, 0); |
1da177e4 LT |
530 | } |
531 | ||
532 | static inline void | |
533 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
534 | { | |
3b18152c JA |
535 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
536 | cfq_clear_cfqq_on_rr(cfqq); | |
22e2c507 | 537 | list_move(&cfqq->cfq_list, &cfqd->empty_list); |
1da177e4 LT |
538 | |
539 | BUG_ON(!cfqd->busy_queues); | |
540 | cfqd->busy_queues--; | |
541 | } | |
542 | ||
543 | /* | |
544 | * rb tree support functions | |
545 | */ | |
546 | static inline void cfq_del_crq_rb(struct cfq_rq *crq) | |
547 | { | |
548 | struct cfq_queue *cfqq = crq->cfq_queue; | |
b4878f24 JA |
549 | struct cfq_data *cfqd = cfqq->cfqd; |
550 | const int sync = cfq_crq_is_sync(crq); | |
1da177e4 | 551 | |
b4878f24 JA |
552 | BUG_ON(!cfqq->queued[sync]); |
553 | cfqq->queued[sync]--; | |
1da177e4 | 554 | |
b4878f24 | 555 | cfq_update_next_crq(crq); |
1da177e4 | 556 | |
b4878f24 JA |
557 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
558 | RB_CLEAR_COLOR(&crq->rb_node); | |
1da177e4 | 559 | |
b4878f24 JA |
560 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list)) |
561 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1da177e4 LT |
562 | } |
563 | ||
564 | static struct cfq_rq * | |
565 | __cfq_add_crq_rb(struct cfq_rq *crq) | |
566 | { | |
567 | struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; | |
568 | struct rb_node *parent = NULL; | |
569 | struct cfq_rq *__crq; | |
570 | ||
571 | while (*p) { | |
572 | parent = *p; | |
573 | __crq = rb_entry_crq(parent); | |
574 | ||
575 | if (crq->rb_key < __crq->rb_key) | |
576 | p = &(*p)->rb_left; | |
577 | else if (crq->rb_key > __crq->rb_key) | |
578 | p = &(*p)->rb_right; | |
579 | else | |
580 | return __crq; | |
581 | } | |
582 | ||
583 | rb_link_node(&crq->rb_node, parent, p); | |
584 | return NULL; | |
585 | } | |
586 | ||
587 | static void cfq_add_crq_rb(struct cfq_rq *crq) | |
588 | { | |
589 | struct cfq_queue *cfqq = crq->cfq_queue; | |
590 | struct cfq_data *cfqd = cfqq->cfqd; | |
591 | struct request *rq = crq->request; | |
592 | struct cfq_rq *__alias; | |
593 | ||
594 | crq->rb_key = rq_rb_key(rq); | |
3b18152c | 595 | cfqq->queued[cfq_crq_is_sync(crq)]++; |
1da177e4 LT |
596 | |
597 | /* | |
598 | * looks a little odd, but the first insert might return an alias. | |
599 | * if that happens, put the alias on the dispatch list | |
600 | */ | |
601 | while ((__alias = __cfq_add_crq_rb(crq)) != NULL) | |
b4878f24 | 602 | cfq_dispatch_insert(cfqd->queue, __alias); |
1da177e4 LT |
603 | |
604 | rb_insert_color(&crq->rb_node, &cfqq->sort_list); | |
605 | ||
3b18152c | 606 | if (!cfq_cfqq_on_rr(cfqq)) |
b4878f24 | 607 | cfq_add_cfqq_rr(cfqd, cfqq); |
1da177e4 LT |
608 | |
609 | /* | |
610 | * check if this request is a better next-serve candidate | |
611 | */ | |
612 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
613 | } | |
614 | ||
615 | static inline void | |
616 | cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) | |
617 | { | |
b4878f24 JA |
618 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
619 | cfqq->queued[cfq_crq_is_sync(crq)]--; | |
1da177e4 LT |
620 | |
621 | cfq_add_crq_rb(crq); | |
622 | } | |
623 | ||
22e2c507 JA |
624 | static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) |
625 | ||
1da177e4 | 626 | { |
3b18152c | 627 | struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY); |
1da177e4 LT |
628 | struct rb_node *n; |
629 | ||
630 | if (!cfqq) | |
631 | goto out; | |
632 | ||
633 | n = cfqq->sort_list.rb_node; | |
634 | while (n) { | |
635 | struct cfq_rq *crq = rb_entry_crq(n); | |
636 | ||
637 | if (sector < crq->rb_key) | |
638 | n = n->rb_left; | |
639 | else if (sector > crq->rb_key) | |
640 | n = n->rb_right; | |
641 | else | |
642 | return crq->request; | |
643 | } | |
644 | ||
645 | out: | |
646 | return NULL; | |
647 | } | |
648 | ||
b4878f24 | 649 | static void cfq_activate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 650 | { |
22e2c507 | 651 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 652 | |
b4878f24 | 653 | cfqd->rq_in_driver++; |
1da177e4 LT |
654 | } |
655 | ||
b4878f24 | 656 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 657 | { |
b4878f24 JA |
658 | struct cfq_data *cfqd = q->elevator->elevator_data; |
659 | ||
660 | WARN_ON(!cfqd->rq_in_driver); | |
661 | cfqd->rq_in_driver--; | |
1da177e4 LT |
662 | } |
663 | ||
b4878f24 | 664 | static void cfq_remove_request(struct request *rq) |
1da177e4 LT |
665 | { |
666 | struct cfq_rq *crq = RQ_DATA(rq); | |
667 | ||
b4878f24 JA |
668 | list_del_init(&rq->queuelist); |
669 | cfq_del_crq_rb(crq); | |
98b11471 | 670 | cfq_del_crq_hash(crq); |
1da177e4 LT |
671 | } |
672 | ||
673 | static int | |
674 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
675 | { | |
676 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
677 | struct request *__rq; | |
678 | int ret; | |
679 | ||
1da177e4 | 680 | __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); |
22e2c507 JA |
681 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
682 | ret = ELEVATOR_BACK_MERGE; | |
683 | goto out; | |
1da177e4 LT |
684 | } |
685 | ||
686 | __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); | |
22e2c507 JA |
687 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
688 | ret = ELEVATOR_FRONT_MERGE; | |
689 | goto out; | |
1da177e4 LT |
690 | } |
691 | ||
692 | return ELEVATOR_NO_MERGE; | |
693 | out: | |
1da177e4 LT |
694 | *req = __rq; |
695 | return ret; | |
696 | } | |
697 | ||
698 | static void cfq_merged_request(request_queue_t *q, struct request *req) | |
699 | { | |
700 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
701 | struct cfq_rq *crq = RQ_DATA(req); | |
702 | ||
703 | cfq_del_crq_hash(crq); | |
704 | cfq_add_crq_hash(cfqd, crq); | |
705 | ||
b4878f24 | 706 | if (rq_rb_key(req) != crq->rb_key) { |
1da177e4 LT |
707 | struct cfq_queue *cfqq = crq->cfq_queue; |
708 | ||
709 | cfq_update_next_crq(crq); | |
710 | cfq_reposition_crq_rb(cfqq, crq); | |
711 | } | |
1da177e4 LT |
712 | } |
713 | ||
714 | static void | |
715 | cfq_merged_requests(request_queue_t *q, struct request *rq, | |
716 | struct request *next) | |
717 | { | |
1da177e4 LT |
718 | cfq_merged_request(q, rq); |
719 | ||
22e2c507 JA |
720 | /* |
721 | * reposition in fifo if next is older than rq | |
722 | */ | |
723 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
724 | time_before(next->start_time, rq->start_time)) | |
725 | list_move(&rq->queuelist, &next->queuelist); | |
726 | ||
b4878f24 | 727 | cfq_remove_request(next); |
22e2c507 JA |
728 | } |
729 | ||
730 | static inline void | |
731 | __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
732 | { | |
733 | if (cfqq) { | |
734 | /* | |
735 | * stop potential idle class queues waiting service | |
736 | */ | |
737 | del_timer(&cfqd->idle_class_timer); | |
738 | ||
739 | cfqq->slice_start = jiffies; | |
740 | cfqq->slice_end = 0; | |
741 | cfqq->slice_left = 0; | |
3b18152c JA |
742 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
743 | cfq_clear_cfqq_fifo_expire(cfqq); | |
22e2c507 JA |
744 | } |
745 | ||
746 | cfqd->active_queue = cfqq; | |
747 | } | |
748 | ||
7b14e3b5 JA |
749 | /* |
750 | * current cfqq expired its slice (or was too idle), select new one | |
751 | */ | |
752 | static void | |
753 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
754 | int preempted) | |
755 | { | |
756 | unsigned long now = jiffies; | |
757 | ||
758 | if (cfq_cfqq_wait_request(cfqq)) | |
759 | del_timer(&cfqd->idle_slice_timer); | |
760 | ||
761 | if (!preempted && !cfq_cfqq_dispatched(cfqq)) { | |
762 | cfqq->service_last = now; | |
763 | cfq_schedule_dispatch(cfqd); | |
764 | } | |
765 | ||
766 | cfq_clear_cfqq_must_dispatch(cfqq); | |
767 | cfq_clear_cfqq_wait_request(cfqq); | |
768 | ||
769 | /* | |
770 | * store what was left of this slice, if the queue idled out | |
771 | * or was preempted | |
772 | */ | |
773 | if (time_after(cfqq->slice_end, now)) | |
774 | cfqq->slice_left = cfqq->slice_end - now; | |
775 | else | |
776 | cfqq->slice_left = 0; | |
777 | ||
778 | if (cfq_cfqq_on_rr(cfqq)) | |
779 | cfq_resort_rr_list(cfqq, preempted); | |
780 | ||
781 | if (cfqq == cfqd->active_queue) | |
782 | cfqd->active_queue = NULL; | |
783 | ||
784 | if (cfqd->active_cic) { | |
785 | put_io_context(cfqd->active_cic->ioc); | |
786 | cfqd->active_cic = NULL; | |
787 | } | |
788 | ||
789 | cfqd->dispatch_slice = 0; | |
790 | } | |
791 | ||
792 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) | |
793 | { | |
794 | struct cfq_queue *cfqq = cfqd->active_queue; | |
795 | ||
796 | if (cfqq) | |
797 | __cfq_slice_expired(cfqd, cfqq, preempted); | |
798 | } | |
799 | ||
22e2c507 JA |
800 | /* |
801 | * 0 | |
802 | * 0,1 | |
803 | * 0,1,2 | |
804 | * 0,1,2,3 | |
805 | * 0,1,2,3,4 | |
806 | * 0,1,2,3,4,5 | |
807 | * 0,1,2,3,4,5,6 | |
808 | * 0,1,2,3,4,5,6,7 | |
809 | */ | |
810 | static int cfq_get_next_prio_level(struct cfq_data *cfqd) | |
811 | { | |
812 | int prio, wrap; | |
813 | ||
814 | prio = -1; | |
815 | wrap = 0; | |
816 | do { | |
817 | int p; | |
818 | ||
819 | for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { | |
820 | if (!list_empty(&cfqd->rr_list[p])) { | |
821 | prio = p; | |
822 | break; | |
823 | } | |
824 | } | |
825 | ||
826 | if (prio != -1) | |
827 | break; | |
828 | cfqd->cur_prio = 0; | |
829 | if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
830 | cfqd->cur_end_prio = 0; | |
831 | if (wrap) | |
832 | break; | |
833 | wrap = 1; | |
1da177e4 | 834 | } |
22e2c507 JA |
835 | } while (1); |
836 | ||
837 | if (unlikely(prio == -1)) | |
838 | return -1; | |
839 | ||
840 | BUG_ON(prio >= CFQ_PRIO_LISTS); | |
841 | ||
842 | list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); | |
843 | ||
844 | cfqd->cur_prio = prio + 1; | |
845 | if (cfqd->cur_prio > cfqd->cur_end_prio) { | |
846 | cfqd->cur_end_prio = cfqd->cur_prio; | |
847 | cfqd->cur_prio = 0; | |
848 | } | |
849 | if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
850 | cfqd->cur_prio = 0; | |
851 | cfqd->cur_end_prio = 0; | |
1da177e4 LT |
852 | } |
853 | ||
22e2c507 JA |
854 | return prio; |
855 | } | |
856 | ||
3b18152c | 857 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
22e2c507 | 858 | { |
7b14e3b5 | 859 | struct cfq_queue *cfqq = NULL; |
22e2c507 JA |
860 | |
861 | /* | |
862 | * if current list is non-empty, grab first entry. if it is empty, | |
863 | * get next prio level and grab first entry then if any are spliced | |
864 | */ | |
865 | if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) | |
866 | cfqq = list_entry_cfqq(cfqd->cur_rr.next); | |
867 | ||
868 | /* | |
869 | * if we have idle queues and no rt or be queues had pending | |
870 | * requests, either allow immediate service if the grace period | |
871 | * has passed or arm the idle grace timer | |
872 | */ | |
873 | if (!cfqq && !list_empty(&cfqd->idle_rr)) { | |
874 | unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
875 | ||
876 | if (time_after_eq(jiffies, end)) | |
877 | cfqq = list_entry_cfqq(cfqd->idle_rr.next); | |
878 | else | |
879 | mod_timer(&cfqd->idle_class_timer, end); | |
880 | } | |
881 | ||
882 | __cfq_set_active_queue(cfqd, cfqq); | |
3b18152c | 883 | return cfqq; |
22e2c507 JA |
884 | } |
885 | ||
22e2c507 JA |
886 | static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
887 | ||
888 | { | |
7b14e3b5 JA |
889 | unsigned long sl; |
890 | ||
22e2c507 JA |
891 | WARN_ON(!RB_EMPTY(&cfqq->sort_list)); |
892 | WARN_ON(cfqq != cfqd->active_queue); | |
893 | ||
894 | /* | |
895 | * idle is disabled, either manually or by past process history | |
896 | */ | |
897 | if (!cfqd->cfq_slice_idle) | |
898 | return 0; | |
3b18152c | 899 | if (!cfq_cfqq_idle_window(cfqq)) |
22e2c507 JA |
900 | return 0; |
901 | /* | |
902 | * task has exited, don't wait | |
903 | */ | |
904 | if (cfqd->active_cic && !cfqd->active_cic->ioc->task) | |
905 | return 0; | |
906 | ||
3b18152c JA |
907 | cfq_mark_cfqq_must_dispatch(cfqq); |
908 | cfq_mark_cfqq_wait_request(cfqq); | |
22e2c507 | 909 | |
7b14e3b5 JA |
910 | sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
911 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); | |
22e2c507 | 912 | return 1; |
1da177e4 LT |
913 | } |
914 | ||
b4878f24 | 915 | static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) |
1da177e4 LT |
916 | { |
917 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
918 | struct cfq_queue *cfqq = crq->cfq_queue; | |
22e2c507 JA |
919 | |
920 | cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); | |
b4878f24 | 921 | cfq_remove_request(crq->request); |
3b18152c | 922 | cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; |
b4878f24 | 923 | elv_dispatch_sort(q, crq->request); |
1da177e4 LT |
924 | } |
925 | ||
926 | /* | |
927 | * return expired entry, or NULL to just start from scratch in rbtree | |
928 | */ | |
929 | static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) | |
930 | { | |
931 | struct cfq_data *cfqd = cfqq->cfqd; | |
22e2c507 | 932 | struct request *rq; |
1da177e4 LT |
933 | struct cfq_rq *crq; |
934 | ||
3b18152c | 935 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 LT |
936 | return NULL; |
937 | ||
22e2c507 | 938 | if (!list_empty(&cfqq->fifo)) { |
3b18152c | 939 | int fifo = cfq_cfqq_class_sync(cfqq); |
1da177e4 | 940 | |
22e2c507 JA |
941 | crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); |
942 | rq = crq->request; | |
943 | if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { | |
3b18152c | 944 | cfq_mark_cfqq_fifo_expire(cfqq); |
22e2c507 JA |
945 | return crq; |
946 | } | |
1da177e4 LT |
947 | } |
948 | ||
949 | return NULL; | |
950 | } | |
951 | ||
952 | /* | |
3b18152c JA |
953 | * Scale schedule slice based on io priority. Use the sync time slice only |
954 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
955 | * io only, should not get full sync slice length. | |
1da177e4 | 956 | */ |
22e2c507 JA |
957 | static inline int |
958 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
959 | { | |
960 | const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; | |
961 | ||
962 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); | |
963 | ||
964 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); | |
965 | } | |
966 | ||
1da177e4 | 967 | static inline void |
22e2c507 | 968 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 969 | { |
22e2c507 JA |
970 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
971 | } | |
1da177e4 | 972 | |
22e2c507 JA |
973 | static inline int |
974 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
975 | { | |
976 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 977 | |
22e2c507 | 978 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 979 | |
22e2c507 | 980 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
981 | } |
982 | ||
22e2c507 JA |
983 | /* |
984 | * get next queue for service | |
985 | */ | |
1b5ed5e1 | 986 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 987 | { |
22e2c507 | 988 | unsigned long now = jiffies; |
1da177e4 | 989 | struct cfq_queue *cfqq; |
1da177e4 | 990 | |
22e2c507 JA |
991 | cfqq = cfqd->active_queue; |
992 | if (!cfqq) | |
993 | goto new_queue; | |
1da177e4 | 994 | |
22e2c507 JA |
995 | /* |
996 | * slice has expired | |
997 | */ | |
3b18152c JA |
998 | if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) |
999 | goto expire; | |
1da177e4 | 1000 | |
22e2c507 JA |
1001 | /* |
1002 | * if queue has requests, dispatch one. if not, check if | |
1003 | * enough slice is left to wait for one | |
1004 | */ | |
1005 | if (!RB_EMPTY(&cfqq->sort_list)) | |
1006 | goto keep_queue; | |
1b5ed5e1 | 1007 | else if (cfq_cfqq_class_sync(cfqq) && |
22e2c507 JA |
1008 | time_before(now, cfqq->slice_end)) { |
1009 | if (cfq_arm_slice_timer(cfqd, cfqq)) | |
1010 | return NULL; | |
1011 | } | |
1012 | ||
3b18152c | 1013 | expire: |
22e2c507 | 1014 | cfq_slice_expired(cfqd, 0); |
3b18152c JA |
1015 | new_queue: |
1016 | cfqq = cfq_set_active_queue(cfqd); | |
22e2c507 | 1017 | keep_queue: |
3b18152c | 1018 | return cfqq; |
22e2c507 JA |
1019 | } |
1020 | ||
1021 | static int | |
1022 | __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1023 | int max_dispatch) | |
1024 | { | |
1025 | int dispatched = 0; | |
1026 | ||
1027 | BUG_ON(RB_EMPTY(&cfqq->sort_list)); | |
1028 | ||
1029 | do { | |
1030 | struct cfq_rq *crq; | |
1da177e4 LT |
1031 | |
1032 | /* | |
22e2c507 | 1033 | * follow expired path, else get first next available |
1da177e4 | 1034 | */ |
22e2c507 JA |
1035 | if ((crq = cfq_check_fifo(cfqq)) == NULL) |
1036 | crq = cfqq->next_crq; | |
1037 | ||
1038 | /* | |
1039 | * finally, insert request into driver dispatch list | |
1040 | */ | |
b4878f24 | 1041 | cfq_dispatch_insert(cfqd->queue, crq); |
1da177e4 | 1042 | |
22e2c507 JA |
1043 | cfqd->dispatch_slice++; |
1044 | dispatched++; | |
1da177e4 | 1045 | |
22e2c507 JA |
1046 | if (!cfqd->active_cic) { |
1047 | atomic_inc(&crq->io_context->ioc->refcount); | |
1048 | cfqd->active_cic = crq->io_context; | |
1049 | } | |
1da177e4 | 1050 | |
22e2c507 JA |
1051 | if (RB_EMPTY(&cfqq->sort_list)) |
1052 | break; | |
1053 | ||
1054 | } while (dispatched < max_dispatch); | |
1055 | ||
1056 | /* | |
1057 | * if slice end isn't set yet, set it. if at least one request was | |
1058 | * sync, use the sync time slice value | |
1059 | */ | |
1060 | if (!cfqq->slice_end) | |
1061 | cfq_set_prio_slice(cfqd, cfqq); | |
1062 | ||
1063 | /* | |
1064 | * expire an async queue immediately if it has used up its slice. idle | |
1065 | * queue always expire after 1 dispatch round. | |
1066 | */ | |
1067 | if ((!cfq_cfqq_sync(cfqq) && | |
1068 | cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
1069 | cfq_class_idle(cfqq)) | |
1070 | cfq_slice_expired(cfqd, 0); | |
1071 | ||
1072 | return dispatched; | |
1073 | } | |
1074 | ||
1b5ed5e1 TH |
1075 | static int |
1076 | cfq_forced_dispatch_cfqqs(struct list_head *list) | |
1077 | { | |
1078 | int dispatched = 0; | |
1079 | struct cfq_queue *cfqq, *next; | |
1080 | struct cfq_rq *crq; | |
1081 | ||
1082 | list_for_each_entry_safe(cfqq, next, list, cfq_list) { | |
1083 | while ((crq = cfqq->next_crq)) { | |
1084 | cfq_dispatch_insert(cfqq->cfqd->queue, crq); | |
1085 | dispatched++; | |
1086 | } | |
1087 | BUG_ON(!list_empty(&cfqq->fifo)); | |
1088 | } | |
1089 | return dispatched; | |
1090 | } | |
1091 | ||
1092 | static int | |
1093 | cfq_forced_dispatch(struct cfq_data *cfqd) | |
1094 | { | |
1095 | int i, dispatched = 0; | |
1096 | ||
1097 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
1098 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]); | |
1099 | ||
1100 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr); | |
1101 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr); | |
1102 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr); | |
1103 | ||
1104 | cfq_slice_expired(cfqd, 0); | |
1105 | ||
1106 | BUG_ON(cfqd->busy_queues); | |
1107 | ||
1108 | return dispatched; | |
1109 | } | |
1110 | ||
22e2c507 | 1111 | static int |
b4878f24 | 1112 | cfq_dispatch_requests(request_queue_t *q, int force) |
22e2c507 JA |
1113 | { |
1114 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1115 | struct cfq_queue *cfqq; | |
1116 | ||
1117 | if (!cfqd->busy_queues) | |
1118 | return 0; | |
1119 | ||
1b5ed5e1 TH |
1120 | if (unlikely(force)) |
1121 | return cfq_forced_dispatch(cfqd); | |
1122 | ||
1123 | cfqq = cfq_select_queue(cfqd); | |
22e2c507 | 1124 | if (cfqq) { |
b4878f24 JA |
1125 | int max_dispatch; |
1126 | ||
1127 | /* | |
1128 | * if idle window is disabled, allow queue buildup | |
1129 | */ | |
1130 | if (!cfq_cfqq_idle_window(cfqq) && | |
1131 | cfqd->rq_in_driver >= cfqd->cfq_max_depth) | |
1132 | return 0; | |
1133 | ||
3b18152c JA |
1134 | cfq_clear_cfqq_must_dispatch(cfqq); |
1135 | cfq_clear_cfqq_wait_request(cfqq); | |
22e2c507 JA |
1136 | del_timer(&cfqd->idle_slice_timer); |
1137 | ||
1b5ed5e1 TH |
1138 | max_dispatch = cfqd->cfq_quantum; |
1139 | if (cfq_class_idle(cfqq)) | |
1140 | max_dispatch = 1; | |
1da177e4 | 1141 | |
22e2c507 | 1142 | return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
1da177e4 LT |
1143 | } |
1144 | ||
22e2c507 | 1145 | return 0; |
1da177e4 LT |
1146 | } |
1147 | ||
1da177e4 LT |
1148 | /* |
1149 | * task holds one reference to the queue, dropped when task exits. each crq | |
1150 | * in-flight on this queue also holds a reference, dropped when crq is freed. | |
1151 | * | |
1152 | * queue lock must be held here. | |
1153 | */ | |
1154 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
1155 | { | |
22e2c507 JA |
1156 | struct cfq_data *cfqd = cfqq->cfqd; |
1157 | ||
1158 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
1159 | |
1160 | if (!atomic_dec_and_test(&cfqq->ref)) | |
1161 | return; | |
1162 | ||
1163 | BUG_ON(rb_first(&cfqq->sort_list)); | |
22e2c507 | 1164 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3b18152c | 1165 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 1166 | |
7b14e3b5 | 1167 | if (unlikely(cfqd->active_queue == cfqq)) |
3b18152c | 1168 | __cfq_slice_expired(cfqd, cfqq, 0); |
22e2c507 | 1169 | |
1da177e4 LT |
1170 | cfq_put_cfqd(cfqq->cfqd); |
1171 | ||
1172 | /* | |
1173 | * it's on the empty list and still hashed | |
1174 | */ | |
1175 | list_del(&cfqq->cfq_list); | |
1176 | hlist_del(&cfqq->cfq_hash); | |
1177 | kmem_cache_free(cfq_pool, cfqq); | |
1178 | } | |
1179 | ||
1180 | static inline struct cfq_queue * | |
3b18152c JA |
1181 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, |
1182 | const int hashval) | |
1da177e4 LT |
1183 | { |
1184 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; | |
1185 | struct hlist_node *entry, *next; | |
1186 | ||
1187 | hlist_for_each_safe(entry, next, hash_list) { | |
1188 | struct cfq_queue *__cfqq = list_entry_qhash(entry); | |
b0a6916b | 1189 | const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio); |
1da177e4 | 1190 | |
3b18152c | 1191 | if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY)) |
1da177e4 LT |
1192 | return __cfqq; |
1193 | } | |
1194 | ||
1195 | return NULL; | |
1196 | } | |
1197 | ||
1198 | static struct cfq_queue * | |
3b18152c | 1199 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) |
1da177e4 | 1200 | { |
3b18152c | 1201 | return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); |
1da177e4 LT |
1202 | } |
1203 | ||
22e2c507 | 1204 | static void cfq_free_io_context(struct cfq_io_context *cic) |
1da177e4 | 1205 | { |
22e2c507 JA |
1206 | struct cfq_io_context *__cic; |
1207 | struct list_head *entry, *next; | |
334e94de | 1208 | int freed = 1; |
1da177e4 | 1209 | |
22e2c507 JA |
1210 | list_for_each_safe(entry, next, &cic->list) { |
1211 | __cic = list_entry(entry, struct cfq_io_context, list); | |
1212 | kmem_cache_free(cfq_ioc_pool, __cic); | |
334e94de | 1213 | freed++; |
1da177e4 LT |
1214 | } |
1215 | ||
22e2c507 | 1216 | kmem_cache_free(cfq_ioc_pool, cic); |
334e94de AV |
1217 | if (atomic_sub_and_test(freed, &ioc_count) && ioc_gone) |
1218 | complete(ioc_gone); | |
1da177e4 LT |
1219 | } |
1220 | ||
e17a9489 AV |
1221 | static void cfq_trim(struct io_context *ioc) |
1222 | { | |
1223 | ioc->set_ioprio = NULL; | |
1224 | if (ioc->cic) | |
1225 | cfq_free_io_context(ioc->cic); | |
1226 | } | |
1227 | ||
22e2c507 JA |
1228 | /* |
1229 | * Called with interrupts disabled | |
1230 | */ | |
1231 | static void cfq_exit_single_io_context(struct cfq_io_context *cic) | |
1da177e4 | 1232 | { |
478a82b0 | 1233 | struct cfq_data *cfqd = cic->key; |
d9ff4187 AV |
1234 | request_queue_t *q; |
1235 | ||
1236 | if (!cfqd) | |
1237 | return; | |
1238 | ||
1239 | q = cfqd->queue; | |
22e2c507 JA |
1240 | |
1241 | WARN_ON(!irqs_disabled()); | |
1242 | ||
1243 | spin_lock(q->queue_lock); | |
1244 | ||
12a05732 AV |
1245 | if (cic->cfqq[ASYNC]) { |
1246 | if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue)) | |
1247 | __cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0); | |
1248 | cfq_put_queue(cic->cfqq[ASYNC]); | |
1249 | cic->cfqq[ASYNC] = NULL; | |
1250 | } | |
1251 | ||
1252 | if (cic->cfqq[SYNC]) { | |
1253 | if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue)) | |
1254 | __cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0); | |
1255 | cfq_put_queue(cic->cfqq[SYNC]); | |
1256 | cic->cfqq[SYNC] = NULL; | |
1257 | } | |
22e2c507 | 1258 | |
478a82b0 | 1259 | cic->key = NULL; |
d9ff4187 | 1260 | list_del_init(&cic->queue_list); |
22e2c507 | 1261 | spin_unlock(q->queue_lock); |
1da177e4 LT |
1262 | } |
1263 | ||
1264 | /* | |
22e2c507 JA |
1265 | * Another task may update the task cic list, if it is doing a queue lookup |
1266 | * on its behalf. cfq_cic_lock excludes such concurrent updates | |
1da177e4 LT |
1267 | */ |
1268 | static void cfq_exit_io_context(struct cfq_io_context *cic) | |
1269 | { | |
22e2c507 JA |
1270 | struct cfq_io_context *__cic; |
1271 | struct list_head *entry; | |
1da177e4 LT |
1272 | unsigned long flags; |
1273 | ||
22e2c507 JA |
1274 | local_irq_save(flags); |
1275 | ||
1da177e4 LT |
1276 | /* |
1277 | * put the reference this task is holding to the various queues | |
1278 | */ | |
d9ff4187 | 1279 | read_lock(&cfq_exit_lock); |
22e2c507 | 1280 | list_for_each(entry, &cic->list) { |
1da177e4 | 1281 | __cic = list_entry(entry, struct cfq_io_context, list); |
22e2c507 | 1282 | cfq_exit_single_io_context(__cic); |
1da177e4 LT |
1283 | } |
1284 | ||
22e2c507 | 1285 | cfq_exit_single_io_context(cic); |
d9ff4187 | 1286 | read_unlock(&cfq_exit_lock); |
22e2c507 | 1287 | local_irq_restore(flags); |
1da177e4 LT |
1288 | } |
1289 | ||
22e2c507 | 1290 | static struct cfq_io_context * |
8267e268 | 1291 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1292 | { |
22e2c507 | 1293 | struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); |
1da177e4 LT |
1294 | |
1295 | if (cic) { | |
1da177e4 | 1296 | INIT_LIST_HEAD(&cic->list); |
12a05732 AV |
1297 | cic->cfqq[ASYNC] = NULL; |
1298 | cic->cfqq[SYNC] = NULL; | |
22e2c507 JA |
1299 | cic->key = NULL; |
1300 | cic->last_end_request = jiffies; | |
1301 | cic->ttime_total = 0; | |
1302 | cic->ttime_samples = 0; | |
1303 | cic->ttime_mean = 0; | |
1304 | cic->dtor = cfq_free_io_context; | |
1305 | cic->exit = cfq_exit_io_context; | |
d9ff4187 | 1306 | INIT_LIST_HEAD(&cic->queue_list); |
334e94de | 1307 | atomic_inc(&ioc_count); |
1da177e4 LT |
1308 | } |
1309 | ||
1310 | return cic; | |
1311 | } | |
1312 | ||
22e2c507 JA |
1313 | static void cfq_init_prio_data(struct cfq_queue *cfqq) |
1314 | { | |
1315 | struct task_struct *tsk = current; | |
1316 | int ioprio_class; | |
1317 | ||
3b18152c | 1318 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
1319 | return; |
1320 | ||
1321 | ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); | |
1322 | switch (ioprio_class) { | |
1323 | default: | |
1324 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
1325 | case IOPRIO_CLASS_NONE: | |
1326 | /* | |
1327 | * no prio set, place us in the middle of the BE classes | |
1328 | */ | |
1329 | cfqq->ioprio = task_nice_ioprio(tsk); | |
1330 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1331 | break; | |
1332 | case IOPRIO_CLASS_RT: | |
1333 | cfqq->ioprio = task_ioprio(tsk); | |
1334 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
1335 | break; | |
1336 | case IOPRIO_CLASS_BE: | |
1337 | cfqq->ioprio = task_ioprio(tsk); | |
1338 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1339 | break; | |
1340 | case IOPRIO_CLASS_IDLE: | |
1341 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
1342 | cfqq->ioprio = 7; | |
3b18152c | 1343 | cfq_clear_cfqq_idle_window(cfqq); |
22e2c507 JA |
1344 | break; |
1345 | } | |
1346 | ||
1347 | /* | |
1348 | * keep track of original prio settings in case we have to temporarily | |
1349 | * elevate the priority of this queue | |
1350 | */ | |
1351 | cfqq->org_ioprio = cfqq->ioprio; | |
1352 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
1353 | ||
3b18152c | 1354 | if (cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1355 | cfq_resort_rr_list(cfqq, 0); |
1356 | ||
3b18152c | 1357 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
1358 | } |
1359 | ||
478a82b0 | 1360 | static inline void changed_ioprio(struct cfq_io_context *cic) |
22e2c507 | 1361 | { |
478a82b0 AV |
1362 | struct cfq_data *cfqd = cic->key; |
1363 | struct cfq_queue *cfqq; | |
1364 | if (cfqd) { | |
22e2c507 | 1365 | spin_lock(cfqd->queue->queue_lock); |
12a05732 AV |
1366 | cfqq = cic->cfqq[ASYNC]; |
1367 | if (cfqq) { | |
1368 | cfq_mark_cfqq_prio_changed(cfqq); | |
1369 | cfq_init_prio_data(cfqq); | |
1370 | } | |
1371 | cfqq = cic->cfqq[SYNC]; | |
478a82b0 AV |
1372 | if (cfqq) { |
1373 | cfq_mark_cfqq_prio_changed(cfqq); | |
1374 | cfq_init_prio_data(cfqq); | |
1375 | } | |
22e2c507 JA |
1376 | spin_unlock(cfqd->queue->queue_lock); |
1377 | } | |
1378 | } | |
1379 | ||
1380 | /* | |
1381 | * callback from sys_ioprio_set, irqs are disabled | |
1382 | */ | |
1383 | static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) | |
1384 | { | |
a6a0763a AV |
1385 | struct cfq_io_context *cic; |
1386 | ||
1387 | write_lock(&cfq_exit_lock); | |
1388 | ||
1389 | cic = ioc->cic; | |
22e2c507 | 1390 | |
478a82b0 | 1391 | changed_ioprio(cic); |
22e2c507 JA |
1392 | |
1393 | list_for_each_entry(cic, &cic->list, list) | |
478a82b0 | 1394 | changed_ioprio(cic); |
22e2c507 | 1395 | |
a6a0763a AV |
1396 | write_unlock(&cfq_exit_lock); |
1397 | ||
22e2c507 JA |
1398 | return 0; |
1399 | } | |
1400 | ||
1401 | static struct cfq_queue * | |
3b18152c | 1402 | cfq_get_queue(struct cfq_data *cfqd, unsigned int key, unsigned short ioprio, |
8267e268 | 1403 | gfp_t gfp_mask) |
22e2c507 JA |
1404 | { |
1405 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); | |
1406 | struct cfq_queue *cfqq, *new_cfqq = NULL; | |
1407 | ||
1408 | retry: | |
3b18152c | 1409 | cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); |
22e2c507 JA |
1410 | |
1411 | if (!cfqq) { | |
1412 | if (new_cfqq) { | |
1413 | cfqq = new_cfqq; | |
1414 | new_cfqq = NULL; | |
1415 | } else if (gfp_mask & __GFP_WAIT) { | |
1416 | spin_unlock_irq(cfqd->queue->queue_lock); | |
1417 | new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1418 | spin_lock_irq(cfqd->queue->queue_lock); | |
1419 | goto retry; | |
1420 | } else { | |
1421 | cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1422 | if (!cfqq) | |
1423 | goto out; | |
1424 | } | |
1425 | ||
1426 | memset(cfqq, 0, sizeof(*cfqq)); | |
1427 | ||
1428 | INIT_HLIST_NODE(&cfqq->cfq_hash); | |
1429 | INIT_LIST_HEAD(&cfqq->cfq_list); | |
1430 | RB_CLEAR_ROOT(&cfqq->sort_list); | |
1431 | INIT_LIST_HEAD(&cfqq->fifo); | |
1432 | ||
1433 | cfqq->key = key; | |
1434 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); | |
1435 | atomic_set(&cfqq->ref, 0); | |
1436 | cfqq->cfqd = cfqd; | |
1437 | atomic_inc(&cfqd->ref); | |
1438 | cfqq->service_last = 0; | |
1439 | /* | |
1440 | * set ->slice_left to allow preemption for a new process | |
1441 | */ | |
1442 | cfqq->slice_left = 2 * cfqd->cfq_slice_idle; | |
3b18152c JA |
1443 | cfq_mark_cfqq_idle_window(cfqq); |
1444 | cfq_mark_cfqq_prio_changed(cfqq); | |
1445 | cfq_init_prio_data(cfqq); | |
22e2c507 JA |
1446 | } |
1447 | ||
1448 | if (new_cfqq) | |
1449 | kmem_cache_free(cfq_pool, new_cfqq); | |
1450 | ||
1451 | atomic_inc(&cfqq->ref); | |
1452 | out: | |
1453 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); | |
1454 | return cfqq; | |
1455 | } | |
1456 | ||
1da177e4 LT |
1457 | /* |
1458 | * Setup general io context and cfq io context. There can be several cfq | |
1459 | * io contexts per general io context, if this process is doing io to more | |
1460 | * than one device managed by cfq. Note that caller is holding a reference to | |
1461 | * cfqq, so we don't need to worry about it disappearing | |
1462 | */ | |
1463 | static struct cfq_io_context * | |
8267e268 | 1464 | cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, gfp_t gfp_mask) |
1da177e4 | 1465 | { |
22e2c507 | 1466 | struct io_context *ioc = NULL; |
1da177e4 | 1467 | struct cfq_io_context *cic; |
1da177e4 | 1468 | |
22e2c507 | 1469 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 1470 | |
22e2c507 | 1471 | ioc = get_io_context(gfp_mask); |
1da177e4 LT |
1472 | if (!ioc) |
1473 | return NULL; | |
1474 | ||
d9ff4187 | 1475 | restart: |
1da177e4 | 1476 | if ((cic = ioc->cic) == NULL) { |
22e2c507 | 1477 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4 LT |
1478 | |
1479 | if (cic == NULL) | |
1480 | goto err; | |
1481 | ||
22e2c507 JA |
1482 | /* |
1483 | * manually increment generic io_context usage count, it | |
1484 | * cannot go away since we are already holding one ref to it | |
1485 | */ | |
1da177e4 | 1486 | cic->ioc = ioc; |
22e2c507 | 1487 | cic->key = cfqd; |
a6a0763a | 1488 | read_lock(&cfq_exit_lock); |
478a82b0 AV |
1489 | ioc->set_ioprio = cfq_ioc_set_ioprio; |
1490 | ioc->cic = cic; | |
d9ff4187 | 1491 | list_add(&cic->queue_list, &cfqd->cic_list); |
a6a0763a | 1492 | read_unlock(&cfq_exit_lock); |
1da177e4 LT |
1493 | } else { |
1494 | struct cfq_io_context *__cic; | |
1da177e4 LT |
1495 | |
1496 | /* | |
22e2c507 | 1497 | * the first cic on the list is actually the head itself |
1da177e4 | 1498 | */ |
22e2c507 | 1499 | if (cic->key == cfqd) |
1da177e4 LT |
1500 | goto out; |
1501 | ||
d9ff4187 AV |
1502 | if (unlikely(!cic->key)) { |
1503 | read_lock(&cfq_exit_lock); | |
1504 | if (list_empty(&cic->list)) | |
1505 | ioc->cic = NULL; | |
1506 | else | |
1507 | ioc->cic = list_entry(cic->list.next, | |
1508 | struct cfq_io_context, | |
1509 | list); | |
1510 | read_unlock(&cfq_exit_lock); | |
1511 | kmem_cache_free(cfq_ioc_pool, cic); | |
334e94de | 1512 | atomic_dec(&ioc_count); |
d9ff4187 AV |
1513 | goto restart; |
1514 | } | |
1515 | ||
1da177e4 LT |
1516 | /* |
1517 | * cic exists, check if we already are there. linear search | |
1518 | * should be ok here, the list will usually not be more than | |
1519 | * 1 or a few entries long | |
1520 | */ | |
1da177e4 LT |
1521 | list_for_each_entry(__cic, &cic->list, list) { |
1522 | /* | |
1523 | * this process is already holding a reference to | |
1524 | * this queue, so no need to get one more | |
1525 | */ | |
22e2c507 | 1526 | if (__cic->key == cfqd) { |
1da177e4 | 1527 | cic = __cic; |
1da177e4 LT |
1528 | goto out; |
1529 | } | |
d9ff4187 AV |
1530 | if (unlikely(!__cic->key)) { |
1531 | read_lock(&cfq_exit_lock); | |
1532 | list_del(&__cic->list); | |
1533 | read_unlock(&cfq_exit_lock); | |
1534 | kmem_cache_free(cfq_ioc_pool, __cic); | |
334e94de | 1535 | atomic_dec(&ioc_count); |
d9ff4187 AV |
1536 | goto restart; |
1537 | } | |
1da177e4 | 1538 | } |
1da177e4 LT |
1539 | |
1540 | /* | |
1541 | * nope, process doesn't have a cic assoicated with this | |
1542 | * cfqq yet. get a new one and add to list | |
1543 | */ | |
22e2c507 | 1544 | __cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4 LT |
1545 | if (__cic == NULL) |
1546 | goto err; | |
1547 | ||
1548 | __cic->ioc = ioc; | |
22e2c507 | 1549 | __cic->key = cfqd; |
a6a0763a | 1550 | read_lock(&cfq_exit_lock); |
1da177e4 | 1551 | list_add(&__cic->list, &cic->list); |
d9ff4187 | 1552 | list_add(&__cic->queue_list, &cfqd->cic_list); |
a6a0763a | 1553 | read_unlock(&cfq_exit_lock); |
1da177e4 | 1554 | cic = __cic; |
1da177e4 LT |
1555 | } |
1556 | ||
1557 | out: | |
1da177e4 LT |
1558 | return cic; |
1559 | err: | |
1560 | put_io_context(ioc); | |
1561 | return NULL; | |
1562 | } | |
1563 | ||
22e2c507 JA |
1564 | static void |
1565 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 1566 | { |
22e2c507 | 1567 | unsigned long elapsed, ttime; |
1da177e4 | 1568 | |
22e2c507 JA |
1569 | /* |
1570 | * if this context already has stuff queued, thinktime is from | |
1571 | * last queue not last end | |
1572 | */ | |
1573 | #if 0 | |
1574 | if (time_after(cic->last_end_request, cic->last_queue)) | |
1575 | elapsed = jiffies - cic->last_end_request; | |
1576 | else | |
1577 | elapsed = jiffies - cic->last_queue; | |
1578 | #else | |
1579 | elapsed = jiffies - cic->last_end_request; | |
1580 | #endif | |
1da177e4 | 1581 | |
22e2c507 | 1582 | ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
db3b5848 | 1583 | |
22e2c507 JA |
1584 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
1585 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
1586 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
1587 | } | |
1da177e4 | 1588 | |
22e2c507 | 1589 | #define sample_valid(samples) ((samples) > 80) |
1da177e4 | 1590 | |
22e2c507 JA |
1591 | /* |
1592 | * Disable idle window if the process thinks too long or seeks so much that | |
1593 | * it doesn't matter | |
1594 | */ | |
1595 | static void | |
1596 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1597 | struct cfq_io_context *cic) | |
1598 | { | |
3b18152c | 1599 | int enable_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 1600 | |
22e2c507 JA |
1601 | if (!cic->ioc->task || !cfqd->cfq_slice_idle) |
1602 | enable_idle = 0; | |
1603 | else if (sample_valid(cic->ttime_samples)) { | |
1604 | if (cic->ttime_mean > cfqd->cfq_slice_idle) | |
1605 | enable_idle = 0; | |
1606 | else | |
1607 | enable_idle = 1; | |
1da177e4 LT |
1608 | } |
1609 | ||
3b18152c JA |
1610 | if (enable_idle) |
1611 | cfq_mark_cfqq_idle_window(cfqq); | |
1612 | else | |
1613 | cfq_clear_cfqq_idle_window(cfqq); | |
22e2c507 | 1614 | } |
1da177e4 | 1615 | |
22e2c507 JA |
1616 | |
1617 | /* | |
1618 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
1619 | * no or if we aren't sure, a 1 will cause a preempt. | |
1620 | */ | |
1621 | static int | |
1622 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, | |
1623 | struct cfq_rq *crq) | |
1624 | { | |
1625 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1626 | ||
1627 | if (cfq_class_idle(new_cfqq)) | |
1628 | return 0; | |
1629 | ||
1630 | if (!cfqq) | |
1631 | return 1; | |
1632 | ||
1633 | if (cfq_class_idle(cfqq)) | |
1634 | return 1; | |
3b18152c | 1635 | if (!cfq_cfqq_wait_request(new_cfqq)) |
22e2c507 JA |
1636 | return 0; |
1637 | /* | |
1638 | * if it doesn't have slice left, forget it | |
1639 | */ | |
1640 | if (new_cfqq->slice_left < cfqd->cfq_slice_idle) | |
1641 | return 0; | |
3b18152c | 1642 | if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq)) |
22e2c507 JA |
1643 | return 1; |
1644 | ||
1645 | return 0; | |
1646 | } | |
1647 | ||
1648 | /* | |
1649 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
1650 | * let it have half of its nominal slice. | |
1651 | */ | |
1652 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1653 | { | |
1654 | struct cfq_queue *__cfqq, *next; | |
1655 | ||
1656 | list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) | |
1657 | cfq_resort_rr_list(__cfqq, 1); | |
1658 | ||
1659 | if (!cfqq->slice_left) | |
1660 | cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; | |
1661 | ||
1662 | cfqq->slice_end = cfqq->slice_left + jiffies; | |
3b18152c | 1663 | __cfq_slice_expired(cfqd, cfqq, 1); |
22e2c507 JA |
1664 | __cfq_set_active_queue(cfqd, cfqq); |
1665 | } | |
1666 | ||
1667 | /* | |
1668 | * should really be a ll_rw_blk.c helper | |
1669 | */ | |
1670 | static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1671 | { | |
1672 | request_queue_t *q = cfqd->queue; | |
1673 | ||
1674 | if (!blk_queue_plugged(q)) | |
1675 | q->request_fn(q); | |
1676 | else | |
1677 | __generic_unplug_device(q); | |
1678 | } | |
1679 | ||
1680 | /* | |
1681 | * Called when a new fs request (crq) is added (to cfqq). Check if there's | |
1682 | * something we should do about it | |
1683 | */ | |
1684 | static void | |
1685 | cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1686 | struct cfq_rq *crq) | |
1687 | { | |
9c2c38a1 | 1688 | struct cfq_io_context *cic; |
22e2c507 JA |
1689 | |
1690 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
1691 | ||
9c2c38a1 JA |
1692 | /* |
1693 | * we never wait for an async request and we don't allow preemption | |
1694 | * of an async request. so just return early | |
1695 | */ | |
1696 | if (!cfq_crq_is_sync(crq)) | |
1697 | return; | |
22e2c507 | 1698 | |
9c2c38a1 | 1699 | cic = crq->io_context; |
22e2c507 | 1700 | |
9c2c38a1 JA |
1701 | cfq_update_io_thinktime(cfqd, cic); |
1702 | cfq_update_idle_window(cfqd, cfqq, cic); | |
1703 | ||
1704 | cic->last_queue = jiffies; | |
22e2c507 JA |
1705 | |
1706 | if (cfqq == cfqd->active_queue) { | |
1707 | /* | |
1708 | * if we are waiting for a request for this queue, let it rip | |
1709 | * immediately and flag that we must not expire this queue | |
1710 | * just now | |
1711 | */ | |
3b18152c JA |
1712 | if (cfq_cfqq_wait_request(cfqq)) { |
1713 | cfq_mark_cfqq_must_dispatch(cfqq); | |
22e2c507 JA |
1714 | del_timer(&cfqd->idle_slice_timer); |
1715 | cfq_start_queueing(cfqd, cfqq); | |
1716 | } | |
1717 | } else if (cfq_should_preempt(cfqd, cfqq, crq)) { | |
1718 | /* | |
1719 | * not the active queue - expire current slice if it is | |
1720 | * idle and has expired it's mean thinktime or this new queue | |
1721 | * has some old slice time left and is of higher priority | |
1722 | */ | |
1723 | cfq_preempt_queue(cfqd, cfqq); | |
3b18152c | 1724 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
1725 | cfq_start_queueing(cfqd, cfqq); |
1726 | } | |
1da177e4 LT |
1727 | } |
1728 | ||
b4878f24 | 1729 | static void cfq_insert_request(request_queue_t *q, struct request *rq) |
1da177e4 | 1730 | { |
b4878f24 | 1731 | struct cfq_data *cfqd = q->elevator->elevator_data; |
22e2c507 JA |
1732 | struct cfq_rq *crq = RQ_DATA(rq); |
1733 | struct cfq_queue *cfqq = crq->cfq_queue; | |
1734 | ||
1735 | cfq_init_prio_data(cfqq); | |
1da177e4 LT |
1736 | |
1737 | cfq_add_crq_rb(crq); | |
1da177e4 | 1738 | |
22e2c507 JA |
1739 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
1740 | ||
98b11471 | 1741 | if (rq_mergeable(rq)) |
22e2c507 JA |
1742 | cfq_add_crq_hash(cfqd, crq); |
1743 | ||
22e2c507 | 1744 | cfq_crq_enqueued(cfqd, cfqq, crq); |
1da177e4 LT |
1745 | } |
1746 | ||
1da177e4 LT |
1747 | static void cfq_completed_request(request_queue_t *q, struct request *rq) |
1748 | { | |
1749 | struct cfq_rq *crq = RQ_DATA(rq); | |
b4878f24 JA |
1750 | struct cfq_queue *cfqq = crq->cfq_queue; |
1751 | struct cfq_data *cfqd = cfqq->cfqd; | |
1752 | const int sync = cfq_crq_is_sync(crq); | |
1753 | unsigned long now; | |
1da177e4 | 1754 | |
b4878f24 | 1755 | now = jiffies; |
1da177e4 | 1756 | |
b4878f24 JA |
1757 | WARN_ON(!cfqd->rq_in_driver); |
1758 | WARN_ON(!cfqq->on_dispatch[sync]); | |
1759 | cfqd->rq_in_driver--; | |
1760 | cfqq->on_dispatch[sync]--; | |
1da177e4 | 1761 | |
b4878f24 JA |
1762 | if (!cfq_class_idle(cfqq)) |
1763 | cfqd->last_end_request = now; | |
3b18152c | 1764 | |
b4878f24 JA |
1765 | if (!cfq_cfqq_dispatched(cfqq)) { |
1766 | if (cfq_cfqq_on_rr(cfqq)) { | |
1767 | cfqq->service_last = now; | |
1768 | cfq_resort_rr_list(cfqq, 0); | |
1769 | } | |
7b14e3b5 | 1770 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
1771 | } |
1772 | ||
b4878f24 JA |
1773 | if (cfq_crq_is_sync(crq)) |
1774 | crq->io_context->last_end_request = now; | |
1da177e4 LT |
1775 | } |
1776 | ||
1777 | static struct request * | |
1778 | cfq_former_request(request_queue_t *q, struct request *rq) | |
1779 | { | |
1780 | struct cfq_rq *crq = RQ_DATA(rq); | |
1781 | struct rb_node *rbprev = rb_prev(&crq->rb_node); | |
1782 | ||
1783 | if (rbprev) | |
1784 | return rb_entry_crq(rbprev)->request; | |
1785 | ||
1786 | return NULL; | |
1787 | } | |
1788 | ||
1789 | static struct request * | |
1790 | cfq_latter_request(request_queue_t *q, struct request *rq) | |
1791 | { | |
1792 | struct cfq_rq *crq = RQ_DATA(rq); | |
1793 | struct rb_node *rbnext = rb_next(&crq->rb_node); | |
1794 | ||
1795 | if (rbnext) | |
1796 | return rb_entry_crq(rbnext)->request; | |
1797 | ||
1798 | return NULL; | |
1799 | } | |
1800 | ||
22e2c507 JA |
1801 | /* |
1802 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
1803 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
1804 | */ | |
1805 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 1806 | { |
22e2c507 JA |
1807 | const int ioprio_class = cfqq->ioprio_class; |
1808 | const int ioprio = cfqq->ioprio; | |
1da177e4 | 1809 | |
22e2c507 JA |
1810 | if (has_fs_excl()) { |
1811 | /* | |
1812 | * boost idle prio on transactions that would lock out other | |
1813 | * users of the filesystem | |
1814 | */ | |
1815 | if (cfq_class_idle(cfqq)) | |
1816 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1817 | if (cfqq->ioprio > IOPRIO_NORM) | |
1818 | cfqq->ioprio = IOPRIO_NORM; | |
1819 | } else { | |
1820 | /* | |
1821 | * check if we need to unboost the queue | |
1822 | */ | |
1823 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) | |
1824 | cfqq->ioprio_class = cfqq->org_ioprio_class; | |
1825 | if (cfqq->ioprio != cfqq->org_ioprio) | |
1826 | cfqq->ioprio = cfqq->org_ioprio; | |
1827 | } | |
1da177e4 | 1828 | |
22e2c507 JA |
1829 | /* |
1830 | * refile between round-robin lists if we moved the priority class | |
1831 | */ | |
1832 | if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && | |
3b18152c | 1833 | cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1834 | cfq_resort_rr_list(cfqq, 0); |
1835 | } | |
1da177e4 | 1836 | |
22e2c507 JA |
1837 | static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
1838 | { | |
1839 | if (rw == READ || process_sync(task)) | |
1840 | return task->pid; | |
1da177e4 | 1841 | |
22e2c507 JA |
1842 | return CFQ_KEY_ASYNC; |
1843 | } | |
1da177e4 | 1844 | |
22e2c507 JA |
1845 | static inline int |
1846 | __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1847 | struct task_struct *task, int rw) | |
1848 | { | |
3b18152c JA |
1849 | #if 1 |
1850 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && | |
99f95e52 | 1851 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1852 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1853 | return ELV_MQUEUE_MUST; |
3b18152c | 1854 | } |
1da177e4 | 1855 | |
22e2c507 | 1856 | return ELV_MQUEUE_MAY; |
3b18152c | 1857 | #else |
22e2c507 JA |
1858 | if (!cfqq || task->flags & PF_MEMALLOC) |
1859 | return ELV_MQUEUE_MAY; | |
3b18152c JA |
1860 | if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) { |
1861 | if (cfq_cfqq_wait_request(cfqq)) | |
22e2c507 | 1862 | return ELV_MQUEUE_MUST; |
1da177e4 | 1863 | |
22e2c507 JA |
1864 | /* |
1865 | * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we | |
1866 | * can quickly flood the queue with writes from a single task | |
1867 | */ | |
99f95e52 | 1868 | if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1869 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1870 | return ELV_MQUEUE_MUST; |
1da177e4 | 1871 | } |
22e2c507 JA |
1872 | |
1873 | return ELV_MQUEUE_MAY; | |
1da177e4 | 1874 | } |
22e2c507 JA |
1875 | if (cfq_class_idle(cfqq)) |
1876 | return ELV_MQUEUE_NO; | |
1877 | if (cfqq->allocated[rw] >= cfqd->max_queued) { | |
1878 | struct io_context *ioc = get_io_context(GFP_ATOMIC); | |
1879 | int ret = ELV_MQUEUE_NO; | |
1da177e4 | 1880 | |
22e2c507 JA |
1881 | if (ioc && ioc->nr_batch_requests) |
1882 | ret = ELV_MQUEUE_MAY; | |
1883 | ||
1884 | put_io_context(ioc); | |
1885 | return ret; | |
1886 | } | |
1887 | ||
1888 | return ELV_MQUEUE_MAY; | |
1889 | #endif | |
1890 | } | |
1891 | ||
1892 | static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) | |
1893 | { | |
1894 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1895 | struct task_struct *tsk = current; | |
1896 | struct cfq_queue *cfqq; | |
1897 | ||
1898 | /* | |
1899 | * don't force setup of a queue from here, as a call to may_queue | |
1900 | * does not necessarily imply that a request actually will be queued. | |
1901 | * so just lookup a possibly existing queue, or return 'may queue' | |
1902 | * if that fails | |
1903 | */ | |
3b18152c | 1904 | cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); |
22e2c507 JA |
1905 | if (cfqq) { |
1906 | cfq_init_prio_data(cfqq); | |
1907 | cfq_prio_boost(cfqq); | |
1908 | ||
1909 | return __cfq_may_queue(cfqd, cfqq, tsk, rw); | |
1910 | } | |
1911 | ||
1912 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
1913 | } |
1914 | ||
1915 | static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) | |
1916 | { | |
22e2c507 | 1917 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1da177e4 | 1918 | struct request_list *rl = &q->rq; |
1da177e4 | 1919 | |
22e2c507 JA |
1920 | if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) { |
1921 | smp_mb(); | |
1922 | if (waitqueue_active(&rl->wait[READ])) | |
1923 | wake_up(&rl->wait[READ]); | |
1924 | } | |
1925 | ||
1926 | if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) { | |
1927 | smp_mb(); | |
1928 | if (waitqueue_active(&rl->wait[WRITE])) | |
1929 | wake_up(&rl->wait[WRITE]); | |
1930 | } | |
1da177e4 LT |
1931 | } |
1932 | ||
1933 | /* | |
1934 | * queue lock held here | |
1935 | */ | |
1936 | static void cfq_put_request(request_queue_t *q, struct request *rq) | |
1937 | { | |
1938 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1939 | struct cfq_rq *crq = RQ_DATA(rq); | |
1940 | ||
1941 | if (crq) { | |
1942 | struct cfq_queue *cfqq = crq->cfq_queue; | |
22e2c507 | 1943 | const int rw = rq_data_dir(rq); |
1da177e4 | 1944 | |
22e2c507 JA |
1945 | BUG_ON(!cfqq->allocated[rw]); |
1946 | cfqq->allocated[rw]--; | |
1da177e4 | 1947 | |
22e2c507 | 1948 | put_io_context(crq->io_context->ioc); |
1da177e4 LT |
1949 | |
1950 | mempool_free(crq, cfqd->crq_pool); | |
1951 | rq->elevator_private = NULL; | |
1952 | ||
1da177e4 LT |
1953 | cfq_check_waiters(q, cfqq); |
1954 | cfq_put_queue(cfqq); | |
1955 | } | |
1956 | } | |
1957 | ||
1958 | /* | |
22e2c507 | 1959 | * Allocate cfq data structures associated with this request. |
1da177e4 | 1960 | */ |
22e2c507 JA |
1961 | static int |
1962 | cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, | |
8267e268 | 1963 | gfp_t gfp_mask) |
1da177e4 LT |
1964 | { |
1965 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3b18152c | 1966 | struct task_struct *tsk = current; |
1da177e4 LT |
1967 | struct cfq_io_context *cic; |
1968 | const int rw = rq_data_dir(rq); | |
3b18152c | 1969 | pid_t key = cfq_queue_pid(tsk, rw); |
22e2c507 | 1970 | struct cfq_queue *cfqq; |
1da177e4 LT |
1971 | struct cfq_rq *crq; |
1972 | unsigned long flags; | |
12a05732 | 1973 | int is_sync = key != CFQ_KEY_ASYNC; |
1da177e4 LT |
1974 | |
1975 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
1976 | ||
3b18152c | 1977 | cic = cfq_get_io_context(cfqd, key, gfp_mask); |
22e2c507 | 1978 | |
1da177e4 LT |
1979 | spin_lock_irqsave(q->queue_lock, flags); |
1980 | ||
22e2c507 JA |
1981 | if (!cic) |
1982 | goto queue_fail; | |
1983 | ||
12a05732 | 1984 | if (!cic->cfqq[is_sync]) { |
3b18152c | 1985 | cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask); |
22e2c507 JA |
1986 | if (!cfqq) |
1987 | goto queue_fail; | |
1da177e4 | 1988 | |
12a05732 | 1989 | cic->cfqq[is_sync] = cfqq; |
22e2c507 | 1990 | } else |
12a05732 | 1991 | cfqq = cic->cfqq[is_sync]; |
1da177e4 LT |
1992 | |
1993 | cfqq->allocated[rw]++; | |
3b18152c | 1994 | cfq_clear_cfqq_must_alloc(cfqq); |
22e2c507 JA |
1995 | cfqd->rq_starved = 0; |
1996 | atomic_inc(&cfqq->ref); | |
1da177e4 LT |
1997 | spin_unlock_irqrestore(q->queue_lock, flags); |
1998 | ||
1da177e4 LT |
1999 | crq = mempool_alloc(cfqd->crq_pool, gfp_mask); |
2000 | if (crq) { | |
2001 | RB_CLEAR(&crq->rb_node); | |
2002 | crq->rb_key = 0; | |
2003 | crq->request = rq; | |
2004 | INIT_HLIST_NODE(&crq->hash); | |
2005 | crq->cfq_queue = cfqq; | |
2006 | crq->io_context = cic; | |
3b18152c | 2007 | |
12a05732 | 2008 | if (is_sync) |
3b18152c JA |
2009 | cfq_mark_crq_is_sync(crq); |
2010 | else | |
2011 | cfq_clear_crq_is_sync(crq); | |
2012 | ||
1da177e4 | 2013 | rq->elevator_private = crq; |
1da177e4 LT |
2014 | return 0; |
2015 | } | |
2016 | ||
1da177e4 LT |
2017 | spin_lock_irqsave(q->queue_lock, flags); |
2018 | cfqq->allocated[rw]--; | |
22e2c507 | 2019 | if (!(cfqq->allocated[0] + cfqq->allocated[1])) |
3b18152c | 2020 | cfq_mark_cfqq_must_alloc(cfqq); |
1da177e4 | 2021 | cfq_put_queue(cfqq); |
22e2c507 JA |
2022 | queue_fail: |
2023 | if (cic) | |
2024 | put_io_context(cic->ioc); | |
2025 | /* | |
2026 | * mark us rq allocation starved. we need to kickstart the process | |
2027 | * ourselves if there are no pending requests that can do it for us. | |
2028 | * that would be an extremely rare OOM situation | |
2029 | */ | |
2030 | cfqd->rq_starved = 1; | |
3b18152c | 2031 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
2032 | spin_unlock_irqrestore(q->queue_lock, flags); |
2033 | return 1; | |
2034 | } | |
2035 | ||
22e2c507 JA |
2036 | static void cfq_kick_queue(void *data) |
2037 | { | |
2038 | request_queue_t *q = data; | |
2039 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2040 | unsigned long flags; | |
2041 | ||
2042 | spin_lock_irqsave(q->queue_lock, flags); | |
2043 | ||
2044 | if (cfqd->rq_starved) { | |
2045 | struct request_list *rl = &q->rq; | |
2046 | ||
2047 | /* | |
2048 | * we aren't guaranteed to get a request after this, but we | |
2049 | * have to be opportunistic | |
2050 | */ | |
2051 | smp_mb(); | |
2052 | if (waitqueue_active(&rl->wait[READ])) | |
2053 | wake_up(&rl->wait[READ]); | |
2054 | if (waitqueue_active(&rl->wait[WRITE])) | |
2055 | wake_up(&rl->wait[WRITE]); | |
2056 | } | |
2057 | ||
2058 | blk_remove_plug(q); | |
2059 | q->request_fn(q); | |
2060 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2061 | } | |
2062 | ||
2063 | /* | |
2064 | * Timer running if the active_queue is currently idling inside its time slice | |
2065 | */ | |
2066 | static void cfq_idle_slice_timer(unsigned long data) | |
2067 | { | |
2068 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2069 | struct cfq_queue *cfqq; | |
2070 | unsigned long flags; | |
2071 | ||
2072 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2073 | ||
2074 | if ((cfqq = cfqd->active_queue) != NULL) { | |
2075 | unsigned long now = jiffies; | |
2076 | ||
2077 | /* | |
2078 | * expired | |
2079 | */ | |
2080 | if (time_after(now, cfqq->slice_end)) | |
2081 | goto expire; | |
2082 | ||
2083 | /* | |
2084 | * only expire and reinvoke request handler, if there are | |
2085 | * other queues with pending requests | |
2086 | */ | |
b4878f24 | 2087 | if (!cfqd->busy_queues) { |
22e2c507 JA |
2088 | cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end); |
2089 | add_timer(&cfqd->idle_slice_timer); | |
2090 | goto out_cont; | |
2091 | } | |
2092 | ||
2093 | /* | |
2094 | * not expired and it has a request pending, let it dispatch | |
2095 | */ | |
2096 | if (!RB_EMPTY(&cfqq->sort_list)) { | |
3b18152c | 2097 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
2098 | goto out_kick; |
2099 | } | |
2100 | } | |
2101 | expire: | |
2102 | cfq_slice_expired(cfqd, 0); | |
2103 | out_kick: | |
3b18152c | 2104 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2105 | out_cont: |
2106 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2107 | } | |
2108 | ||
2109 | /* | |
2110 | * Timer running if an idle class queue is waiting for service | |
2111 | */ | |
2112 | static void cfq_idle_class_timer(unsigned long data) | |
2113 | { | |
2114 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2115 | unsigned long flags, end; | |
2116 | ||
2117 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2118 | ||
2119 | /* | |
2120 | * race with a non-idle queue, reset timer | |
2121 | */ | |
2122 | end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
2123 | if (!time_after_eq(jiffies, end)) { | |
2124 | cfqd->idle_class_timer.expires = end; | |
2125 | add_timer(&cfqd->idle_class_timer); | |
2126 | } else | |
3b18152c | 2127 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2128 | |
2129 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2130 | } | |
2131 | ||
3b18152c JA |
2132 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
2133 | { | |
2134 | del_timer_sync(&cfqd->idle_slice_timer); | |
2135 | del_timer_sync(&cfqd->idle_class_timer); | |
2136 | blk_sync_queue(cfqd->queue); | |
2137 | } | |
22e2c507 | 2138 | |
1da177e4 LT |
2139 | static void cfq_put_cfqd(struct cfq_data *cfqd) |
2140 | { | |
1da177e4 LT |
2141 | if (!atomic_dec_and_test(&cfqd->ref)) |
2142 | return; | |
2143 | ||
96c51ce9 | 2144 | cfq_shutdown_timer_wq(cfqd); |
96c51ce9 | 2145 | |
1da177e4 LT |
2146 | mempool_destroy(cfqd->crq_pool); |
2147 | kfree(cfqd->crq_hash); | |
2148 | kfree(cfqd->cfq_hash); | |
2149 | kfree(cfqd); | |
2150 | } | |
2151 | ||
2152 | static void cfq_exit_queue(elevator_t *e) | |
2153 | { | |
22e2c507 | 2154 | struct cfq_data *cfqd = e->elevator_data; |
d9ff4187 | 2155 | request_queue_t *q = cfqd->queue; |
22e2c507 | 2156 | |
3b18152c | 2157 | cfq_shutdown_timer_wq(cfqd); |
d9ff4187 AV |
2158 | write_lock(&cfq_exit_lock); |
2159 | spin_lock_irq(q->queue_lock); | |
2160 | if (cfqd->active_queue) | |
2161 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); | |
2162 | while(!list_empty(&cfqd->cic_list)) { | |
2163 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, | |
2164 | struct cfq_io_context, | |
2165 | queue_list); | |
2166 | if (cic->cfqq[ASYNC]) { | |
2167 | cfq_put_queue(cic->cfqq[ASYNC]); | |
2168 | cic->cfqq[ASYNC] = NULL; | |
2169 | } | |
2170 | if (cic->cfqq[SYNC]) { | |
2171 | cfq_put_queue(cic->cfqq[SYNC]); | |
2172 | cic->cfqq[SYNC] = NULL; | |
2173 | } | |
2174 | cic->key = NULL; | |
2175 | list_del_init(&cic->queue_list); | |
2176 | } | |
2177 | spin_unlock_irq(q->queue_lock); | |
2178 | write_unlock(&cfq_exit_lock); | |
22e2c507 | 2179 | cfq_put_cfqd(cfqd); |
1da177e4 LT |
2180 | } |
2181 | ||
2182 | static int cfq_init_queue(request_queue_t *q, elevator_t *e) | |
2183 | { | |
2184 | struct cfq_data *cfqd; | |
2185 | int i; | |
2186 | ||
2187 | cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); | |
2188 | if (!cfqd) | |
2189 | return -ENOMEM; | |
2190 | ||
2191 | memset(cfqd, 0, sizeof(*cfqd)); | |
22e2c507 JA |
2192 | |
2193 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
2194 | INIT_LIST_HEAD(&cfqd->rr_list[i]); | |
2195 | ||
2196 | INIT_LIST_HEAD(&cfqd->busy_rr); | |
2197 | INIT_LIST_HEAD(&cfqd->cur_rr); | |
2198 | INIT_LIST_HEAD(&cfqd->idle_rr); | |
1da177e4 | 2199 | INIT_LIST_HEAD(&cfqd->empty_list); |
d9ff4187 | 2200 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 LT |
2201 | |
2202 | cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); | |
2203 | if (!cfqd->crq_hash) | |
2204 | goto out_crqhash; | |
2205 | ||
2206 | cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); | |
2207 | if (!cfqd->cfq_hash) | |
2208 | goto out_cfqhash; | |
2209 | ||
2210 | cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool); | |
2211 | if (!cfqd->crq_pool) | |
2212 | goto out_crqpool; | |
2213 | ||
2214 | for (i = 0; i < CFQ_MHASH_ENTRIES; i++) | |
2215 | INIT_HLIST_HEAD(&cfqd->crq_hash[i]); | |
2216 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) | |
2217 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); | |
2218 | ||
2219 | e->elevator_data = cfqd; | |
2220 | ||
2221 | cfqd->queue = q; | |
1da177e4 | 2222 | |
22e2c507 | 2223 | cfqd->max_queued = q->nr_requests / 4; |
1da177e4 | 2224 | q->nr_batching = cfq_queued; |
22e2c507 JA |
2225 | |
2226 | init_timer(&cfqd->idle_slice_timer); | |
2227 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
2228 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
2229 | ||
2230 | init_timer(&cfqd->idle_class_timer); | |
2231 | cfqd->idle_class_timer.function = cfq_idle_class_timer; | |
2232 | cfqd->idle_class_timer.data = (unsigned long) cfqd; | |
2233 | ||
2234 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); | |
2235 | ||
1da177e4 LT |
2236 | atomic_set(&cfqd->ref, 1); |
2237 | ||
2238 | cfqd->cfq_queued = cfq_queued; | |
2239 | cfqd->cfq_quantum = cfq_quantum; | |
22e2c507 JA |
2240 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
2241 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
2242 | cfqd->cfq_back_max = cfq_back_max; |
2243 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
2244 | cfqd->cfq_slice[0] = cfq_slice_async; |
2245 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
2246 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
2247 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
2248 | cfqd->cfq_max_depth = cfq_max_depth; | |
3b18152c | 2249 | |
1da177e4 LT |
2250 | return 0; |
2251 | out_crqpool: | |
2252 | kfree(cfqd->cfq_hash); | |
2253 | out_cfqhash: | |
2254 | kfree(cfqd->crq_hash); | |
2255 | out_crqhash: | |
2256 | kfree(cfqd); | |
2257 | return -ENOMEM; | |
2258 | } | |
2259 | ||
2260 | static void cfq_slab_kill(void) | |
2261 | { | |
2262 | if (crq_pool) | |
2263 | kmem_cache_destroy(crq_pool); | |
2264 | if (cfq_pool) | |
2265 | kmem_cache_destroy(cfq_pool); | |
2266 | if (cfq_ioc_pool) | |
2267 | kmem_cache_destroy(cfq_ioc_pool); | |
2268 | } | |
2269 | ||
2270 | static int __init cfq_slab_setup(void) | |
2271 | { | |
2272 | crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, | |
2273 | NULL, NULL); | |
2274 | if (!crq_pool) | |
2275 | goto fail; | |
2276 | ||
2277 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, | |
2278 | NULL, NULL); | |
2279 | if (!cfq_pool) | |
2280 | goto fail; | |
2281 | ||
2282 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", | |
2283 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); | |
2284 | if (!cfq_ioc_pool) | |
2285 | goto fail; | |
2286 | ||
2287 | return 0; | |
2288 | fail: | |
2289 | cfq_slab_kill(); | |
2290 | return -ENOMEM; | |
2291 | } | |
2292 | ||
1da177e4 LT |
2293 | /* |
2294 | * sysfs parts below --> | |
2295 | */ | |
2296 | struct cfq_fs_entry { | |
2297 | struct attribute attr; | |
2298 | ssize_t (*show)(struct cfq_data *, char *); | |
2299 | ssize_t (*store)(struct cfq_data *, const char *, size_t); | |
2300 | }; | |
2301 | ||
2302 | static ssize_t | |
2303 | cfq_var_show(unsigned int var, char *page) | |
2304 | { | |
2305 | return sprintf(page, "%d\n", var); | |
2306 | } | |
2307 | ||
2308 | static ssize_t | |
2309 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
2310 | { | |
2311 | char *p = (char *) page; | |
2312 | ||
2313 | *var = simple_strtoul(p, &p, 10); | |
2314 | return count; | |
2315 | } | |
2316 | ||
1da177e4 LT |
2317 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
2318 | static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \ | |
2319 | { \ | |
2320 | unsigned int __data = __VAR; \ | |
2321 | if (__CONV) \ | |
2322 | __data = jiffies_to_msecs(__data); \ | |
2323 | return cfq_var_show(__data, (page)); \ | |
2324 | } | |
2325 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
2326 | SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); | |
22e2c507 JA |
2327 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
2328 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
1da177e4 LT |
2329 | SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); |
2330 | SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
2331 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
2332 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
2333 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
2334 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
2335 | SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0); | |
1da177e4 LT |
2336 | #undef SHOW_FUNCTION |
2337 | ||
2338 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
2339 | static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \ | |
2340 | { \ | |
2341 | unsigned int __data; \ | |
2342 | int ret = cfq_var_store(&__data, (page), count); \ | |
2343 | if (__data < (MIN)) \ | |
2344 | __data = (MIN); \ | |
2345 | else if (__data > (MAX)) \ | |
2346 | __data = (MAX); \ | |
2347 | if (__CONV) \ | |
2348 | *(__PTR) = msecs_to_jiffies(__data); \ | |
2349 | else \ | |
2350 | *(__PTR) = __data; \ | |
2351 | return ret; \ | |
2352 | } | |
2353 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
2354 | STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); | |
22e2c507 JA |
2355 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); |
2356 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); | |
1da177e4 LT |
2357 | STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
2358 | STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); | |
22e2c507 JA |
2359 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
2360 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
2361 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
2362 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); | |
2363 | STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0); | |
1da177e4 LT |
2364 | #undef STORE_FUNCTION |
2365 | ||
2366 | static struct cfq_fs_entry cfq_quantum_entry = { | |
2367 | .attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR }, | |
2368 | .show = cfq_quantum_show, | |
2369 | .store = cfq_quantum_store, | |
2370 | }; | |
2371 | static struct cfq_fs_entry cfq_queued_entry = { | |
2372 | .attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR }, | |
2373 | .show = cfq_queued_show, | |
2374 | .store = cfq_queued_store, | |
2375 | }; | |
22e2c507 | 2376 | static struct cfq_fs_entry cfq_fifo_expire_sync_entry = { |
1da177e4 | 2377 | .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, |
22e2c507 JA |
2378 | .show = cfq_fifo_expire_sync_show, |
2379 | .store = cfq_fifo_expire_sync_store, | |
1da177e4 | 2380 | }; |
22e2c507 | 2381 | static struct cfq_fs_entry cfq_fifo_expire_async_entry = { |
1da177e4 | 2382 | .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, |
22e2c507 JA |
2383 | .show = cfq_fifo_expire_async_show, |
2384 | .store = cfq_fifo_expire_async_store, | |
1da177e4 LT |
2385 | }; |
2386 | static struct cfq_fs_entry cfq_back_max_entry = { | |
2387 | .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR }, | |
2388 | .show = cfq_back_max_show, | |
2389 | .store = cfq_back_max_store, | |
2390 | }; | |
2391 | static struct cfq_fs_entry cfq_back_penalty_entry = { | |
2392 | .attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR }, | |
2393 | .show = cfq_back_penalty_show, | |
2394 | .store = cfq_back_penalty_store, | |
2395 | }; | |
22e2c507 JA |
2396 | static struct cfq_fs_entry cfq_slice_sync_entry = { |
2397 | .attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR }, | |
2398 | .show = cfq_slice_sync_show, | |
2399 | .store = cfq_slice_sync_store, | |
1da177e4 | 2400 | }; |
22e2c507 JA |
2401 | static struct cfq_fs_entry cfq_slice_async_entry = { |
2402 | .attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR }, | |
2403 | .show = cfq_slice_async_show, | |
2404 | .store = cfq_slice_async_store, | |
2405 | }; | |
2406 | static struct cfq_fs_entry cfq_slice_async_rq_entry = { | |
2407 | .attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR }, | |
2408 | .show = cfq_slice_async_rq_show, | |
2409 | .store = cfq_slice_async_rq_store, | |
2410 | }; | |
2411 | static struct cfq_fs_entry cfq_slice_idle_entry = { | |
2412 | .attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR }, | |
2413 | .show = cfq_slice_idle_show, | |
2414 | .store = cfq_slice_idle_store, | |
2415 | }; | |
2416 | static struct cfq_fs_entry cfq_max_depth_entry = { | |
2417 | .attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR }, | |
2418 | .show = cfq_max_depth_show, | |
2419 | .store = cfq_max_depth_store, | |
1da177e4 | 2420 | }; |
3b18152c | 2421 | |
1da177e4 LT |
2422 | static struct attribute *default_attrs[] = { |
2423 | &cfq_quantum_entry.attr, | |
2424 | &cfq_queued_entry.attr, | |
22e2c507 JA |
2425 | &cfq_fifo_expire_sync_entry.attr, |
2426 | &cfq_fifo_expire_async_entry.attr, | |
1da177e4 LT |
2427 | &cfq_back_max_entry.attr, |
2428 | &cfq_back_penalty_entry.attr, | |
22e2c507 JA |
2429 | &cfq_slice_sync_entry.attr, |
2430 | &cfq_slice_async_entry.attr, | |
2431 | &cfq_slice_async_rq_entry.attr, | |
2432 | &cfq_slice_idle_entry.attr, | |
2433 | &cfq_max_depth_entry.attr, | |
1da177e4 LT |
2434 | NULL, |
2435 | }; | |
2436 | ||
2437 | #define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr) | |
2438 | ||
2439 | static ssize_t | |
2440 | cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page) | |
2441 | { | |
2442 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
2443 | struct cfq_fs_entry *entry = to_cfq(attr); | |
2444 | ||
2445 | if (!entry->show) | |
6c1852a0 | 2446 | return -EIO; |
1da177e4 LT |
2447 | |
2448 | return entry->show(e->elevator_data, page); | |
2449 | } | |
2450 | ||
2451 | static ssize_t | |
2452 | cfq_attr_store(struct kobject *kobj, struct attribute *attr, | |
2453 | const char *page, size_t length) | |
2454 | { | |
2455 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
2456 | struct cfq_fs_entry *entry = to_cfq(attr); | |
2457 | ||
2458 | if (!entry->store) | |
6c1852a0 | 2459 | return -EIO; |
1da177e4 LT |
2460 | |
2461 | return entry->store(e->elevator_data, page, length); | |
2462 | } | |
2463 | ||
2464 | static struct sysfs_ops cfq_sysfs_ops = { | |
2465 | .show = cfq_attr_show, | |
2466 | .store = cfq_attr_store, | |
2467 | }; | |
2468 | ||
2469 | static struct kobj_type cfq_ktype = { | |
2470 | .sysfs_ops = &cfq_sysfs_ops, | |
2471 | .default_attrs = default_attrs, | |
2472 | }; | |
2473 | ||
2474 | static struct elevator_type iosched_cfq = { | |
2475 | .ops = { | |
2476 | .elevator_merge_fn = cfq_merge, | |
2477 | .elevator_merged_fn = cfq_merged_request, | |
2478 | .elevator_merge_req_fn = cfq_merged_requests, | |
b4878f24 | 2479 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 2480 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 2481 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
2482 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
2483 | .elevator_queue_empty_fn = cfq_queue_empty, | |
2484 | .elevator_completed_req_fn = cfq_completed_request, | |
2485 | .elevator_former_req_fn = cfq_former_request, | |
2486 | .elevator_latter_req_fn = cfq_latter_request, | |
2487 | .elevator_set_req_fn = cfq_set_request, | |
2488 | .elevator_put_req_fn = cfq_put_request, | |
2489 | .elevator_may_queue_fn = cfq_may_queue, | |
2490 | .elevator_init_fn = cfq_init_queue, | |
2491 | .elevator_exit_fn = cfq_exit_queue, | |
e17a9489 | 2492 | .trim = cfq_trim, |
1da177e4 LT |
2493 | }, |
2494 | .elevator_ktype = &cfq_ktype, | |
2495 | .elevator_name = "cfq", | |
2496 | .elevator_owner = THIS_MODULE, | |
2497 | }; | |
2498 | ||
2499 | static int __init cfq_init(void) | |
2500 | { | |
2501 | int ret; | |
2502 | ||
22e2c507 JA |
2503 | /* |
2504 | * could be 0 on HZ < 1000 setups | |
2505 | */ | |
2506 | if (!cfq_slice_async) | |
2507 | cfq_slice_async = 1; | |
2508 | if (!cfq_slice_idle) | |
2509 | cfq_slice_idle = 1; | |
2510 | ||
1da177e4 LT |
2511 | if (cfq_slab_setup()) |
2512 | return -ENOMEM; | |
2513 | ||
2514 | ret = elv_register(&iosched_cfq); | |
22e2c507 JA |
2515 | if (ret) |
2516 | cfq_slab_kill(); | |
1da177e4 | 2517 | |
1da177e4 LT |
2518 | return ret; |
2519 | } | |
2520 | ||
2521 | static void __exit cfq_exit(void) | |
2522 | { | |
334e94de | 2523 | DECLARE_COMPLETION(all_gone); |
1da177e4 | 2524 | elv_unregister(&iosched_cfq); |
334e94de AV |
2525 | ioc_gone = &all_gone; |
2526 | barrier(); | |
2527 | if (atomic_read(&ioc_count)) | |
2528 | complete(ioc_gone); | |
2529 | synchronize_rcu(); | |
83521d3e | 2530 | cfq_slab_kill(); |
1da177e4 LT |
2531 | } |
2532 | ||
2533 | module_init(cfq_init); | |
2534 | module_exit(cfq_exit); | |
2535 | ||
2536 | MODULE_AUTHOR("Jens Axboe"); | |
2537 | MODULE_LICENSE("GPL"); | |
2538 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |