Commit | Line | Data |
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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 | 9 | #include <linux/module.h> |
1cc9be68 AV |
10 | #include <linux/blkdev.h> |
11 | #include <linux/elevator.h> | |
1da177e4 LT |
12 | #include <linux/hash.h> |
13 | #include <linux/rbtree.h> | |
22e2c507 | 14 | #include <linux/ioprio.h> |
1da177e4 LT |
15 | |
16 | /* | |
17 | * tunables | |
18 | */ | |
64100099 AV |
19 | static const int cfq_quantum = 4; /* max queue in one round of service */ |
20 | static const int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ | |
21 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; | |
22 | static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ | |
23 | static const int cfq_back_penalty = 2; /* penalty of a backwards seek */ | |
1da177e4 | 24 | |
64100099 | 25 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 26 | static int cfq_slice_async = HZ / 25; |
64100099 | 27 | static const int cfq_slice_async_rq = 2; |
caaa5f9f | 28 | static int cfq_slice_idle = HZ / 125; |
22e2c507 JA |
29 | |
30 | #define CFQ_IDLE_GRACE (HZ / 10) | |
31 | #define CFQ_SLICE_SCALE (5) | |
32 | ||
33 | #define CFQ_KEY_ASYNC (0) | |
22e2c507 | 34 | |
3793c65c | 35 | static DEFINE_SPINLOCK(cfq_exit_lock); |
a6a0763a | 36 | |
1da177e4 LT |
37 | /* |
38 | * for the hash of cfqq inside the cfqd | |
39 | */ | |
40 | #define CFQ_QHASH_SHIFT 6 | |
41 | #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) | |
42 | #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) | |
43 | ||
1da177e4 LT |
44 | #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) |
45 | ||
46 | #define RQ_DATA(rq) (rq)->elevator_private | |
47 | ||
1da177e4 LT |
48 | static kmem_cache_t *crq_pool; |
49 | static kmem_cache_t *cfq_pool; | |
50 | static kmem_cache_t *cfq_ioc_pool; | |
51 | ||
334e94de AV |
52 | static atomic_t ioc_count = ATOMIC_INIT(0); |
53 | static struct completion *ioc_gone; | |
54 | ||
22e2c507 JA |
55 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
56 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
57 | #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) | |
58 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) | |
59 | ||
3b18152c JA |
60 | #define ASYNC (0) |
61 | #define SYNC (1) | |
62 | ||
63 | #define cfq_cfqq_dispatched(cfqq) \ | |
64 | ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) | |
65 | ||
66 | #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) | |
67 | ||
68 | #define cfq_cfqq_sync(cfqq) \ | |
69 | (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) | |
22e2c507 | 70 | |
206dc69b JA |
71 | #define sample_valid(samples) ((samples) > 80) |
72 | ||
22e2c507 JA |
73 | /* |
74 | * Per block device queue structure | |
75 | */ | |
1da177e4 | 76 | struct cfq_data { |
22e2c507 JA |
77 | request_queue_t *queue; |
78 | ||
79 | /* | |
80 | * rr list of queues with requests and the count of them | |
81 | */ | |
82 | struct list_head rr_list[CFQ_PRIO_LISTS]; | |
83 | struct list_head busy_rr; | |
84 | struct list_head cur_rr; | |
85 | struct list_head idle_rr; | |
86 | unsigned int busy_queues; | |
87 | ||
88 | /* | |
89 | * non-ordered list of empty cfqq's | |
90 | */ | |
1da177e4 LT |
91 | struct list_head empty_list; |
92 | ||
22e2c507 JA |
93 | /* |
94 | * cfqq lookup hash | |
95 | */ | |
1da177e4 | 96 | struct hlist_head *cfq_hash; |
1da177e4 | 97 | |
22e2c507 | 98 | mempool_t *crq_pool; |
1da177e4 | 99 | |
22e2c507 | 100 | int rq_in_driver; |
25776e35 | 101 | int hw_tag; |
1da177e4 | 102 | |
22e2c507 JA |
103 | /* |
104 | * schedule slice state info | |
105 | */ | |
106 | /* | |
107 | * idle window management | |
108 | */ | |
109 | struct timer_list idle_slice_timer; | |
110 | struct work_struct unplug_work; | |
1da177e4 | 111 | |
22e2c507 JA |
112 | struct cfq_queue *active_queue; |
113 | struct cfq_io_context *active_cic; | |
114 | int cur_prio, cur_end_prio; | |
115 | unsigned int dispatch_slice; | |
116 | ||
117 | struct timer_list idle_class_timer; | |
1da177e4 LT |
118 | |
119 | sector_t last_sector; | |
22e2c507 | 120 | unsigned long last_end_request; |
1da177e4 | 121 | |
22e2c507 | 122 | unsigned int rq_starved; |
1da177e4 LT |
123 | |
124 | /* | |
125 | * tunables, see top of file | |
126 | */ | |
127 | unsigned int cfq_quantum; | |
128 | unsigned int cfq_queued; | |
22e2c507 | 129 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
130 | unsigned int cfq_back_penalty; |
131 | unsigned int cfq_back_max; | |
22e2c507 JA |
132 | unsigned int cfq_slice[2]; |
133 | unsigned int cfq_slice_async_rq; | |
134 | unsigned int cfq_slice_idle; | |
d9ff4187 AV |
135 | |
136 | struct list_head cic_list; | |
1da177e4 LT |
137 | }; |
138 | ||
22e2c507 JA |
139 | /* |
140 | * Per process-grouping structure | |
141 | */ | |
1da177e4 LT |
142 | struct cfq_queue { |
143 | /* reference count */ | |
144 | atomic_t ref; | |
145 | /* parent cfq_data */ | |
146 | struct cfq_data *cfqd; | |
22e2c507 | 147 | /* cfqq lookup hash */ |
1da177e4 LT |
148 | struct hlist_node cfq_hash; |
149 | /* hash key */ | |
22e2c507 | 150 | unsigned int key; |
1da177e4 LT |
151 | /* on either rr or empty list of cfqd */ |
152 | struct list_head cfq_list; | |
153 | /* sorted list of pending requests */ | |
154 | struct rb_root sort_list; | |
155 | /* if fifo isn't expired, next request to serve */ | |
156 | struct cfq_rq *next_crq; | |
157 | /* requests queued in sort_list */ | |
158 | int queued[2]; | |
159 | /* currently allocated requests */ | |
160 | int allocated[2]; | |
161 | /* fifo list of requests in sort_list */ | |
22e2c507 | 162 | struct list_head fifo; |
1da177e4 | 163 | |
22e2c507 JA |
164 | unsigned long slice_start; |
165 | unsigned long slice_end; | |
166 | unsigned long slice_left; | |
167 | unsigned long service_last; | |
1da177e4 | 168 | |
3b18152c JA |
169 | /* number of requests that are on the dispatch list */ |
170 | int on_dispatch[2]; | |
22e2c507 JA |
171 | |
172 | /* io prio of this group */ | |
173 | unsigned short ioprio, org_ioprio; | |
174 | unsigned short ioprio_class, org_ioprio_class; | |
175 | ||
3b18152c JA |
176 | /* various state flags, see below */ |
177 | unsigned int flags; | |
1da177e4 LT |
178 | }; |
179 | ||
180 | struct cfq_rq { | |
1da177e4 | 181 | struct request *request; |
1da177e4 LT |
182 | |
183 | struct cfq_queue *cfq_queue; | |
184 | struct cfq_io_context *io_context; | |
1da177e4 LT |
185 | }; |
186 | ||
3b18152c JA |
187 | enum cfqq_state_flags { |
188 | CFQ_CFQQ_FLAG_on_rr = 0, | |
189 | CFQ_CFQQ_FLAG_wait_request, | |
190 | CFQ_CFQQ_FLAG_must_alloc, | |
191 | CFQ_CFQQ_FLAG_must_alloc_slice, | |
192 | CFQ_CFQQ_FLAG_must_dispatch, | |
193 | CFQ_CFQQ_FLAG_fifo_expire, | |
194 | CFQ_CFQQ_FLAG_idle_window, | |
195 | CFQ_CFQQ_FLAG_prio_changed, | |
3b18152c JA |
196 | }; |
197 | ||
198 | #define CFQ_CFQQ_FNS(name) \ | |
199 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
200 | { \ | |
201 | cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ | |
202 | } \ | |
203 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
204 | { \ | |
205 | cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ | |
206 | } \ | |
207 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
208 | { \ | |
209 | return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ | |
210 | } | |
211 | ||
212 | CFQ_CFQQ_FNS(on_rr); | |
213 | CFQ_CFQQ_FNS(wait_request); | |
214 | CFQ_CFQQ_FNS(must_alloc); | |
215 | CFQ_CFQQ_FNS(must_alloc_slice); | |
216 | CFQ_CFQQ_FNS(must_dispatch); | |
217 | CFQ_CFQQ_FNS(fifo_expire); | |
218 | CFQ_CFQQ_FNS(idle_window); | |
219 | CFQ_CFQQ_FNS(prio_changed); | |
3b18152c JA |
220 | #undef CFQ_CFQQ_FNS |
221 | ||
3b18152c | 222 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); |
b4878f24 | 223 | static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); |
6f325a13 | 224 | static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); |
1da177e4 | 225 | |
99f95e52 AM |
226 | /* |
227 | * scheduler run of queue, if there are requests pending and no one in the | |
228 | * driver that will restart queueing | |
229 | */ | |
230 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) | |
231 | { | |
7b14e3b5 | 232 | if (cfqd->busy_queues) |
99f95e52 AM |
233 | kblockd_schedule_work(&cfqd->unplug_work); |
234 | } | |
235 | ||
236 | static int cfq_queue_empty(request_queue_t *q) | |
237 | { | |
238 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
239 | ||
b4878f24 | 240 | return !cfqd->busy_queues; |
99f95e52 AM |
241 | } |
242 | ||
206dc69b JA |
243 | static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
244 | { | |
b31dc66a | 245 | if (rw == READ || rw == WRITE_SYNC) |
206dc69b JA |
246 | return task->pid; |
247 | ||
248 | return CFQ_KEY_ASYNC; | |
249 | } | |
250 | ||
1da177e4 LT |
251 | /* |
252 | * Lifted from AS - choose which of crq1 and crq2 that is best served now. | |
253 | * We choose the request that is closest to the head right now. Distance | |
e8a99053 | 254 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 LT |
255 | */ |
256 | static struct cfq_rq * | |
257 | cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) | |
258 | { | |
259 | sector_t last, s1, s2, d1 = 0, d2 = 0; | |
1da177e4 | 260 | unsigned long back_max; |
e8a99053 AM |
261 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
262 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
263 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 LT |
264 | |
265 | if (crq1 == NULL || crq1 == crq2) | |
266 | return crq2; | |
267 | if (crq2 == NULL) | |
268 | return crq1; | |
9c2c38a1 | 269 | |
5380a101 | 270 | if (rq_is_sync(crq1->request) && !rq_is_sync(crq2->request)) |
9c2c38a1 | 271 | return crq1; |
5380a101 | 272 | else if (rq_is_sync(crq2->request) && !rq_is_sync(crq1->request)) |
22e2c507 | 273 | return crq2; |
1da177e4 LT |
274 | |
275 | s1 = crq1->request->sector; | |
276 | s2 = crq2->request->sector; | |
277 | ||
278 | last = cfqd->last_sector; | |
279 | ||
1da177e4 LT |
280 | /* |
281 | * by definition, 1KiB is 2 sectors | |
282 | */ | |
283 | back_max = cfqd->cfq_back_max * 2; | |
284 | ||
285 | /* | |
286 | * Strict one way elevator _except_ in the case where we allow | |
287 | * short backward seeks which are biased as twice the cost of a | |
288 | * similar forward seek. | |
289 | */ | |
290 | if (s1 >= last) | |
291 | d1 = s1 - last; | |
292 | else if (s1 + back_max >= last) | |
293 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
294 | else | |
e8a99053 | 295 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
296 | |
297 | if (s2 >= last) | |
298 | d2 = s2 - last; | |
299 | else if (s2 + back_max >= last) | |
300 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
301 | else | |
e8a99053 | 302 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
303 | |
304 | /* Found required data */ | |
e8a99053 AM |
305 | |
306 | /* | |
307 | * By doing switch() on the bit mask "wrap" we avoid having to | |
308 | * check two variables for all permutations: --> faster! | |
309 | */ | |
310 | switch (wrap) { | |
311 | case 0: /* common case for CFQ: crq1 and crq2 not wrapped */ | |
312 | if (d1 < d2) | |
1da177e4 | 313 | return crq1; |
e8a99053 | 314 | else if (d2 < d1) |
1da177e4 | 315 | return crq2; |
e8a99053 AM |
316 | else { |
317 | if (s1 >= s2) | |
318 | return crq1; | |
319 | else | |
320 | return crq2; | |
321 | } | |
1da177e4 | 322 | |
e8a99053 | 323 | case CFQ_RQ2_WRAP: |
1da177e4 | 324 | return crq1; |
e8a99053 | 325 | case CFQ_RQ1_WRAP: |
1da177e4 | 326 | return crq2; |
e8a99053 AM |
327 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both crqs wrapped */ |
328 | default: | |
329 | /* | |
330 | * Since both rqs are wrapped, | |
331 | * start with the one that's further behind head | |
332 | * (--> only *one* back seek required), | |
333 | * since back seek takes more time than forward. | |
334 | */ | |
335 | if (s1 <= s2) | |
1da177e4 LT |
336 | return crq1; |
337 | else | |
338 | return crq2; | |
339 | } | |
340 | } | |
341 | ||
342 | /* | |
343 | * would be nice to take fifo expire time into account as well | |
344 | */ | |
345 | static struct cfq_rq * | |
346 | cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
21183b07 | 347 | struct cfq_rq *last_crq) |
1da177e4 | 348 | { |
21183b07 JA |
349 | struct request *last = last_crq->request; |
350 | struct rb_node *rbnext = rb_next(&last->rb_node); | |
351 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
352 | struct cfq_rq *next = NULL, *prev = NULL; | |
1da177e4 | 353 | |
21183b07 | 354 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
355 | |
356 | if (rbprev) | |
21183b07 | 357 | prev = RQ_DATA(rb_entry_rq(rbprev)); |
1da177e4 | 358 | |
21183b07 JA |
359 | if (rbnext) |
360 | next = RQ_DATA(rb_entry_rq(rbnext)); | |
361 | else { | |
362 | rbnext = rb_first(&cfqq->sort_list); | |
363 | if (rbnext && rbnext != &last->rb_node) | |
364 | next = RQ_DATA(rb_entry_rq(rbnext)); | |
365 | } | |
1da177e4 | 366 | |
21183b07 | 367 | return cfq_choose_req(cfqd, next, prev); |
1da177e4 LT |
368 | } |
369 | ||
22e2c507 | 370 | static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
1da177e4 | 371 | { |
22e2c507 JA |
372 | struct cfq_data *cfqd = cfqq->cfqd; |
373 | struct list_head *list, *entry; | |
1da177e4 | 374 | |
3b18152c | 375 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 376 | |
22e2c507 | 377 | list_del(&cfqq->cfq_list); |
1da177e4 | 378 | |
22e2c507 JA |
379 | if (cfq_class_rt(cfqq)) |
380 | list = &cfqd->cur_rr; | |
381 | else if (cfq_class_idle(cfqq)) | |
382 | list = &cfqd->idle_rr; | |
383 | else { | |
384 | /* | |
385 | * if cfqq has requests in flight, don't allow it to be | |
386 | * found in cfq_set_active_queue before it has finished them. | |
387 | * this is done to increase fairness between a process that | |
388 | * has lots of io pending vs one that only generates one | |
389 | * sporadically or synchronously | |
390 | */ | |
3b18152c | 391 | if (cfq_cfqq_dispatched(cfqq)) |
22e2c507 JA |
392 | list = &cfqd->busy_rr; |
393 | else | |
394 | list = &cfqd->rr_list[cfqq->ioprio]; | |
1da177e4 LT |
395 | } |
396 | ||
22e2c507 JA |
397 | /* |
398 | * if queue was preempted, just add to front to be fair. busy_rr | |
b52a8348 | 399 | * isn't sorted, but insert at the back for fairness. |
22e2c507 JA |
400 | */ |
401 | if (preempted || list == &cfqd->busy_rr) { | |
b52a8348 JA |
402 | if (preempted) |
403 | list = list->prev; | |
404 | ||
405 | list_add_tail(&cfqq->cfq_list, list); | |
1da177e4 | 406 | return; |
22e2c507 | 407 | } |
1da177e4 LT |
408 | |
409 | /* | |
22e2c507 | 410 | * sort by when queue was last serviced |
1da177e4 | 411 | */ |
22e2c507 JA |
412 | entry = list; |
413 | while ((entry = entry->prev) != list) { | |
1da177e4 LT |
414 | struct cfq_queue *__cfqq = list_entry_cfqq(entry); |
415 | ||
22e2c507 JA |
416 | if (!__cfqq->service_last) |
417 | break; | |
418 | if (time_before(__cfqq->service_last, cfqq->service_last)) | |
1da177e4 | 419 | break; |
1da177e4 LT |
420 | } |
421 | ||
422 | list_add(&cfqq->cfq_list, entry); | |
423 | } | |
424 | ||
425 | /* | |
426 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 427 | * the pending list according to last request service |
1da177e4 LT |
428 | */ |
429 | static inline void | |
b4878f24 | 430 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 431 | { |
3b18152c JA |
432 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
433 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
434 | cfqd->busy_queues++; |
435 | ||
b4878f24 | 436 | cfq_resort_rr_list(cfqq, 0); |
1da177e4 LT |
437 | } |
438 | ||
439 | static inline void | |
440 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
441 | { | |
3b18152c JA |
442 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
443 | cfq_clear_cfqq_on_rr(cfqq); | |
22e2c507 | 444 | list_move(&cfqq->cfq_list, &cfqd->empty_list); |
1da177e4 LT |
445 | |
446 | BUG_ON(!cfqd->busy_queues); | |
447 | cfqd->busy_queues--; | |
448 | } | |
449 | ||
450 | /* | |
451 | * rb tree support functions | |
452 | */ | |
453 | static inline void cfq_del_crq_rb(struct cfq_rq *crq) | |
454 | { | |
455 | struct cfq_queue *cfqq = crq->cfq_queue; | |
b4878f24 | 456 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 457 | const int sync = rq_is_sync(crq->request); |
1da177e4 | 458 | |
b4878f24 JA |
459 | BUG_ON(!cfqq->queued[sync]); |
460 | cfqq->queued[sync]--; | |
1da177e4 | 461 | |
21183b07 | 462 | elv_rb_del(&cfqq->sort_list, crq->request); |
1da177e4 | 463 | |
dd67d051 | 464 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
b4878f24 | 465 | cfq_del_cfqq_rr(cfqd, cfqq); |
1da177e4 LT |
466 | } |
467 | ||
1da177e4 LT |
468 | static void cfq_add_crq_rb(struct cfq_rq *crq) |
469 | { | |
470 | struct cfq_queue *cfqq = crq->cfq_queue; | |
471 | struct cfq_data *cfqd = cfqq->cfqd; | |
472 | struct request *rq = crq->request; | |
21183b07 | 473 | struct request *__alias; |
1da177e4 | 474 | |
5380a101 | 475 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
476 | |
477 | /* | |
478 | * looks a little odd, but the first insert might return an alias. | |
479 | * if that happens, put the alias on the dispatch list | |
480 | */ | |
21183b07 JA |
481 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
482 | cfq_dispatch_insert(cfqd->queue, RQ_DATA(__alias)); | |
1da177e4 LT |
483 | } |
484 | ||
485 | static inline void | |
486 | cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) | |
487 | { | |
5380a101 JA |
488 | struct request *rq = crq->request; |
489 | ||
490 | elv_rb_del(&cfqq->sort_list, rq); | |
491 | cfqq->queued[rq_is_sync(rq)]--; | |
1da177e4 LT |
492 | cfq_add_crq_rb(crq); |
493 | } | |
494 | ||
206dc69b JA |
495 | static struct request * |
496 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 497 | { |
206dc69b JA |
498 | struct task_struct *tsk = current; |
499 | pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio)); | |
21183b07 | 500 | sector_t sector = bio->bi_sector + bio_sectors(bio); |
206dc69b | 501 | struct cfq_queue *cfqq; |
1da177e4 | 502 | |
206dc69b | 503 | cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); |
21183b07 JA |
504 | if (cfqq) |
505 | return elv_rb_find(&cfqq->sort_list, sector); | |
1da177e4 | 506 | |
1da177e4 LT |
507 | return NULL; |
508 | } | |
509 | ||
b4878f24 | 510 | static void cfq_activate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 511 | { |
22e2c507 | 512 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 513 | |
b4878f24 | 514 | cfqd->rq_in_driver++; |
25776e35 JA |
515 | |
516 | /* | |
517 | * If the depth is larger 1, it really could be queueing. But lets | |
518 | * make the mark a little higher - idling could still be good for | |
519 | * low queueing, and a low queueing number could also just indicate | |
520 | * a SCSI mid layer like behaviour where limit+1 is often seen. | |
521 | */ | |
522 | if (!cfqd->hw_tag && cfqd->rq_in_driver > 4) | |
523 | cfqd->hw_tag = 1; | |
1da177e4 LT |
524 | } |
525 | ||
b4878f24 | 526 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 527 | { |
b4878f24 JA |
528 | struct cfq_data *cfqd = q->elevator->elevator_data; |
529 | ||
530 | WARN_ON(!cfqd->rq_in_driver); | |
531 | cfqd->rq_in_driver--; | |
1da177e4 LT |
532 | } |
533 | ||
b4878f24 | 534 | static void cfq_remove_request(struct request *rq) |
1da177e4 LT |
535 | { |
536 | struct cfq_rq *crq = RQ_DATA(rq); | |
21183b07 JA |
537 | struct cfq_queue *cfqq = crq->cfq_queue; |
538 | ||
539 | if (cfqq->next_crq == crq) | |
540 | cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); | |
1da177e4 | 541 | |
b4878f24 JA |
542 | list_del_init(&rq->queuelist); |
543 | cfq_del_crq_rb(crq); | |
1da177e4 LT |
544 | } |
545 | ||
546 | static int | |
547 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
548 | { | |
549 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
550 | struct request *__rq; | |
1da177e4 | 551 | |
206dc69b | 552 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 553 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
554 | *req = __rq; |
555 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
556 | } |
557 | ||
558 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
559 | } |
560 | ||
21183b07 JA |
561 | static void cfq_merged_request(request_queue_t *q, struct request *req, |
562 | int type) | |
1da177e4 | 563 | { |
1da177e4 LT |
564 | struct cfq_rq *crq = RQ_DATA(req); |
565 | ||
21183b07 | 566 | if (type == ELEVATOR_FRONT_MERGE) { |
1da177e4 LT |
567 | struct cfq_queue *cfqq = crq->cfq_queue; |
568 | ||
1da177e4 LT |
569 | cfq_reposition_crq_rb(cfqq, crq); |
570 | } | |
1da177e4 LT |
571 | } |
572 | ||
573 | static void | |
574 | cfq_merged_requests(request_queue_t *q, struct request *rq, | |
575 | struct request *next) | |
576 | { | |
22e2c507 JA |
577 | /* |
578 | * reposition in fifo if next is older than rq | |
579 | */ | |
580 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
581 | time_before(next->start_time, rq->start_time)) | |
582 | list_move(&rq->queuelist, &next->queuelist); | |
583 | ||
b4878f24 | 584 | cfq_remove_request(next); |
22e2c507 JA |
585 | } |
586 | ||
587 | static inline void | |
588 | __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
589 | { | |
590 | if (cfqq) { | |
591 | /* | |
592 | * stop potential idle class queues waiting service | |
593 | */ | |
594 | del_timer(&cfqd->idle_class_timer); | |
595 | ||
596 | cfqq->slice_start = jiffies; | |
597 | cfqq->slice_end = 0; | |
598 | cfqq->slice_left = 0; | |
3b18152c JA |
599 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
600 | cfq_clear_cfqq_fifo_expire(cfqq); | |
22e2c507 JA |
601 | } |
602 | ||
603 | cfqd->active_queue = cfqq; | |
604 | } | |
605 | ||
7b14e3b5 JA |
606 | /* |
607 | * current cfqq expired its slice (or was too idle), select new one | |
608 | */ | |
609 | static void | |
610 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
611 | int preempted) | |
612 | { | |
613 | unsigned long now = jiffies; | |
614 | ||
615 | if (cfq_cfqq_wait_request(cfqq)) | |
616 | del_timer(&cfqd->idle_slice_timer); | |
617 | ||
618 | if (!preempted && !cfq_cfqq_dispatched(cfqq)) { | |
619 | cfqq->service_last = now; | |
620 | cfq_schedule_dispatch(cfqd); | |
621 | } | |
622 | ||
623 | cfq_clear_cfqq_must_dispatch(cfqq); | |
624 | cfq_clear_cfqq_wait_request(cfqq); | |
625 | ||
626 | /* | |
627 | * store what was left of this slice, if the queue idled out | |
628 | * or was preempted | |
629 | */ | |
630 | if (time_after(cfqq->slice_end, now)) | |
631 | cfqq->slice_left = cfqq->slice_end - now; | |
632 | else | |
633 | cfqq->slice_left = 0; | |
634 | ||
635 | if (cfq_cfqq_on_rr(cfqq)) | |
636 | cfq_resort_rr_list(cfqq, preempted); | |
637 | ||
638 | if (cfqq == cfqd->active_queue) | |
639 | cfqd->active_queue = NULL; | |
640 | ||
641 | if (cfqd->active_cic) { | |
642 | put_io_context(cfqd->active_cic->ioc); | |
643 | cfqd->active_cic = NULL; | |
644 | } | |
645 | ||
646 | cfqd->dispatch_slice = 0; | |
647 | } | |
648 | ||
649 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) | |
650 | { | |
651 | struct cfq_queue *cfqq = cfqd->active_queue; | |
652 | ||
653 | if (cfqq) | |
654 | __cfq_slice_expired(cfqd, cfqq, preempted); | |
655 | } | |
656 | ||
22e2c507 JA |
657 | /* |
658 | * 0 | |
659 | * 0,1 | |
660 | * 0,1,2 | |
661 | * 0,1,2,3 | |
662 | * 0,1,2,3,4 | |
663 | * 0,1,2,3,4,5 | |
664 | * 0,1,2,3,4,5,6 | |
665 | * 0,1,2,3,4,5,6,7 | |
666 | */ | |
667 | static int cfq_get_next_prio_level(struct cfq_data *cfqd) | |
668 | { | |
669 | int prio, wrap; | |
670 | ||
671 | prio = -1; | |
672 | wrap = 0; | |
673 | do { | |
674 | int p; | |
675 | ||
676 | for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { | |
677 | if (!list_empty(&cfqd->rr_list[p])) { | |
678 | prio = p; | |
679 | break; | |
680 | } | |
681 | } | |
682 | ||
683 | if (prio != -1) | |
684 | break; | |
685 | cfqd->cur_prio = 0; | |
686 | if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
687 | cfqd->cur_end_prio = 0; | |
688 | if (wrap) | |
689 | break; | |
690 | wrap = 1; | |
1da177e4 | 691 | } |
22e2c507 JA |
692 | } while (1); |
693 | ||
694 | if (unlikely(prio == -1)) | |
695 | return -1; | |
696 | ||
697 | BUG_ON(prio >= CFQ_PRIO_LISTS); | |
698 | ||
699 | list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); | |
700 | ||
701 | cfqd->cur_prio = prio + 1; | |
702 | if (cfqd->cur_prio > cfqd->cur_end_prio) { | |
703 | cfqd->cur_end_prio = cfqd->cur_prio; | |
704 | cfqd->cur_prio = 0; | |
705 | } | |
706 | if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
707 | cfqd->cur_prio = 0; | |
708 | cfqd->cur_end_prio = 0; | |
1da177e4 LT |
709 | } |
710 | ||
22e2c507 JA |
711 | return prio; |
712 | } | |
713 | ||
3b18152c | 714 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
22e2c507 | 715 | { |
7b14e3b5 | 716 | struct cfq_queue *cfqq = NULL; |
22e2c507 JA |
717 | |
718 | /* | |
719 | * if current list is non-empty, grab first entry. if it is empty, | |
720 | * get next prio level and grab first entry then if any are spliced | |
721 | */ | |
722 | if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) | |
723 | cfqq = list_entry_cfqq(cfqd->cur_rr.next); | |
724 | ||
e0de0206 JA |
725 | /* |
726 | * If no new queues are available, check if the busy list has some | |
727 | * before falling back to idle io. | |
728 | */ | |
729 | if (!cfqq && !list_empty(&cfqd->busy_rr)) | |
730 | cfqq = list_entry_cfqq(cfqd->busy_rr.next); | |
731 | ||
22e2c507 JA |
732 | /* |
733 | * if we have idle queues and no rt or be queues had pending | |
734 | * requests, either allow immediate service if the grace period | |
735 | * has passed or arm the idle grace timer | |
736 | */ | |
737 | if (!cfqq && !list_empty(&cfqd->idle_rr)) { | |
738 | unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
739 | ||
740 | if (time_after_eq(jiffies, end)) | |
741 | cfqq = list_entry_cfqq(cfqd->idle_rr.next); | |
742 | else | |
743 | mod_timer(&cfqd->idle_class_timer, end); | |
744 | } | |
745 | ||
746 | __cfq_set_active_queue(cfqd, cfqq); | |
3b18152c | 747 | return cfqq; |
22e2c507 JA |
748 | } |
749 | ||
caaa5f9f JA |
750 | #define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024)) |
751 | ||
22e2c507 JA |
752 | static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
753 | ||
754 | { | |
206dc69b | 755 | struct cfq_io_context *cic; |
7b14e3b5 JA |
756 | unsigned long sl; |
757 | ||
dd67d051 | 758 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
22e2c507 JA |
759 | WARN_ON(cfqq != cfqd->active_queue); |
760 | ||
761 | /* | |
762 | * idle is disabled, either manually or by past process history | |
763 | */ | |
764 | if (!cfqd->cfq_slice_idle) | |
765 | return 0; | |
3b18152c | 766 | if (!cfq_cfqq_idle_window(cfqq)) |
22e2c507 JA |
767 | return 0; |
768 | /* | |
769 | * task has exited, don't wait | |
770 | */ | |
206dc69b JA |
771 | cic = cfqd->active_cic; |
772 | if (!cic || !cic->ioc->task) | |
22e2c507 JA |
773 | return 0; |
774 | ||
3b18152c JA |
775 | cfq_mark_cfqq_must_dispatch(cfqq); |
776 | cfq_mark_cfqq_wait_request(cfqq); | |
22e2c507 | 777 | |
7b14e3b5 | 778 | sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
206dc69b JA |
779 | |
780 | /* | |
781 | * we don't want to idle for seeks, but we do want to allow | |
782 | * fair distribution of slice time for a process doing back-to-back | |
783 | * seeks. so allow a little bit of time for him to submit a new rq | |
784 | */ | |
caaa5f9f | 785 | if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic)) |
44eb1231 | 786 | sl = min(sl, msecs_to_jiffies(2)); |
206dc69b | 787 | |
7b14e3b5 | 788 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
22e2c507 | 789 | return 1; |
1da177e4 LT |
790 | } |
791 | ||
b4878f24 | 792 | static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) |
1da177e4 LT |
793 | { |
794 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
795 | struct cfq_queue *cfqq = crq->cfq_queue; | |
5380a101 | 796 | struct request *rq = crq->request; |
22e2c507 | 797 | |
5380a101 JA |
798 | cfq_remove_request(rq); |
799 | cfqq->on_dispatch[rq_is_sync(rq)]++; | |
800 | elv_dispatch_sort(q, rq); | |
fd61af03 JA |
801 | |
802 | rq = list_entry(q->queue_head.prev, struct request, queuelist); | |
803 | cfqd->last_sector = rq->sector + rq->nr_sectors; | |
1da177e4 LT |
804 | } |
805 | ||
806 | /* | |
807 | * return expired entry, or NULL to just start from scratch in rbtree | |
808 | */ | |
809 | static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) | |
810 | { | |
811 | struct cfq_data *cfqd = cfqq->cfqd; | |
22e2c507 | 812 | struct request *rq; |
1da177e4 LT |
813 | struct cfq_rq *crq; |
814 | ||
3b18152c | 815 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 LT |
816 | return NULL; |
817 | ||
22e2c507 | 818 | if (!list_empty(&cfqq->fifo)) { |
3b18152c | 819 | int fifo = cfq_cfqq_class_sync(cfqq); |
1da177e4 | 820 | |
95e8810b | 821 | crq = RQ_DATA(rq_entry_fifo(cfqq->fifo.next)); |
22e2c507 JA |
822 | rq = crq->request; |
823 | if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { | |
3b18152c | 824 | cfq_mark_cfqq_fifo_expire(cfqq); |
22e2c507 JA |
825 | return crq; |
826 | } | |
1da177e4 LT |
827 | } |
828 | ||
829 | return NULL; | |
830 | } | |
831 | ||
832 | /* | |
3b18152c JA |
833 | * Scale schedule slice based on io priority. Use the sync time slice only |
834 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
835 | * io only, should not get full sync slice length. | |
1da177e4 | 836 | */ |
22e2c507 JA |
837 | static inline int |
838 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
839 | { | |
840 | const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; | |
841 | ||
842 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); | |
843 | ||
844 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); | |
845 | } | |
846 | ||
1da177e4 | 847 | static inline void |
22e2c507 | 848 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 849 | { |
22e2c507 JA |
850 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
851 | } | |
1da177e4 | 852 | |
22e2c507 JA |
853 | static inline int |
854 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
855 | { | |
856 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 857 | |
22e2c507 | 858 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 859 | |
22e2c507 | 860 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
861 | } |
862 | ||
22e2c507 JA |
863 | /* |
864 | * get next queue for service | |
865 | */ | |
1b5ed5e1 | 866 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 867 | { |
22e2c507 | 868 | unsigned long now = jiffies; |
1da177e4 | 869 | struct cfq_queue *cfqq; |
1da177e4 | 870 | |
22e2c507 JA |
871 | cfqq = cfqd->active_queue; |
872 | if (!cfqq) | |
873 | goto new_queue; | |
1da177e4 | 874 | |
22e2c507 JA |
875 | /* |
876 | * slice has expired | |
877 | */ | |
3b18152c JA |
878 | if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) |
879 | goto expire; | |
1da177e4 | 880 | |
22e2c507 JA |
881 | /* |
882 | * if queue has requests, dispatch one. if not, check if | |
883 | * enough slice is left to wait for one | |
884 | */ | |
dd67d051 | 885 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 886 | goto keep_queue; |
caaa5f9f JA |
887 | else if (cfq_cfqq_dispatched(cfqq)) { |
888 | cfqq = NULL; | |
889 | goto keep_queue; | |
890 | } else if (cfq_cfqq_class_sync(cfqq)) { | |
22e2c507 JA |
891 | if (cfq_arm_slice_timer(cfqd, cfqq)) |
892 | return NULL; | |
893 | } | |
894 | ||
3b18152c | 895 | expire: |
22e2c507 | 896 | cfq_slice_expired(cfqd, 0); |
3b18152c JA |
897 | new_queue: |
898 | cfqq = cfq_set_active_queue(cfqd); | |
22e2c507 | 899 | keep_queue: |
3b18152c | 900 | return cfqq; |
22e2c507 JA |
901 | } |
902 | ||
903 | static int | |
904 | __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
905 | int max_dispatch) | |
906 | { | |
907 | int dispatched = 0; | |
908 | ||
dd67d051 | 909 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); |
22e2c507 JA |
910 | |
911 | do { | |
912 | struct cfq_rq *crq; | |
1da177e4 LT |
913 | |
914 | /* | |
22e2c507 | 915 | * follow expired path, else get first next available |
1da177e4 | 916 | */ |
22e2c507 JA |
917 | if ((crq = cfq_check_fifo(cfqq)) == NULL) |
918 | crq = cfqq->next_crq; | |
919 | ||
920 | /* | |
921 | * finally, insert request into driver dispatch list | |
922 | */ | |
b4878f24 | 923 | cfq_dispatch_insert(cfqd->queue, crq); |
1da177e4 | 924 | |
22e2c507 JA |
925 | cfqd->dispatch_slice++; |
926 | dispatched++; | |
1da177e4 | 927 | |
22e2c507 JA |
928 | if (!cfqd->active_cic) { |
929 | atomic_inc(&crq->io_context->ioc->refcount); | |
930 | cfqd->active_cic = crq->io_context; | |
931 | } | |
1da177e4 | 932 | |
dd67d051 | 933 | if (RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 JA |
934 | break; |
935 | ||
936 | } while (dispatched < max_dispatch); | |
937 | ||
938 | /* | |
caaa5f9f | 939 | * if slice end isn't set yet, set it. |
22e2c507 JA |
940 | */ |
941 | if (!cfqq->slice_end) | |
942 | cfq_set_prio_slice(cfqd, cfqq); | |
943 | ||
944 | /* | |
945 | * expire an async queue immediately if it has used up its slice. idle | |
946 | * queue always expire after 1 dispatch round. | |
947 | */ | |
948 | if ((!cfq_cfqq_sync(cfqq) && | |
949 | cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
caaa5f9f JA |
950 | cfq_class_idle(cfqq) || |
951 | !cfq_cfqq_idle_window(cfqq)) | |
22e2c507 JA |
952 | cfq_slice_expired(cfqd, 0); |
953 | ||
954 | return dispatched; | |
955 | } | |
956 | ||
1b5ed5e1 TH |
957 | static int |
958 | cfq_forced_dispatch_cfqqs(struct list_head *list) | |
959 | { | |
1b5ed5e1 TH |
960 | struct cfq_queue *cfqq, *next; |
961 | struct cfq_rq *crq; | |
caaa5f9f | 962 | int dispatched; |
1b5ed5e1 | 963 | |
caaa5f9f | 964 | dispatched = 0; |
1b5ed5e1 TH |
965 | list_for_each_entry_safe(cfqq, next, list, cfq_list) { |
966 | while ((crq = cfqq->next_crq)) { | |
967 | cfq_dispatch_insert(cfqq->cfqd->queue, crq); | |
968 | dispatched++; | |
969 | } | |
970 | BUG_ON(!list_empty(&cfqq->fifo)); | |
971 | } | |
caaa5f9f | 972 | |
1b5ed5e1 TH |
973 | return dispatched; |
974 | } | |
975 | ||
976 | static int | |
977 | cfq_forced_dispatch(struct cfq_data *cfqd) | |
978 | { | |
979 | int i, dispatched = 0; | |
980 | ||
981 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
982 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]); | |
983 | ||
984 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr); | |
985 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr); | |
986 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr); | |
987 | ||
988 | cfq_slice_expired(cfqd, 0); | |
989 | ||
990 | BUG_ON(cfqd->busy_queues); | |
991 | ||
992 | return dispatched; | |
993 | } | |
994 | ||
22e2c507 | 995 | static int |
b4878f24 | 996 | cfq_dispatch_requests(request_queue_t *q, int force) |
22e2c507 JA |
997 | { |
998 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
caaa5f9f JA |
999 | struct cfq_queue *cfqq, *prev_cfqq; |
1000 | int dispatched; | |
22e2c507 JA |
1001 | |
1002 | if (!cfqd->busy_queues) | |
1003 | return 0; | |
1004 | ||
1b5ed5e1 TH |
1005 | if (unlikely(force)) |
1006 | return cfq_forced_dispatch(cfqd); | |
1007 | ||
caaa5f9f JA |
1008 | dispatched = 0; |
1009 | prev_cfqq = NULL; | |
1010 | while ((cfqq = cfq_select_queue(cfqd)) != NULL) { | |
b4878f24 JA |
1011 | int max_dispatch; |
1012 | ||
caaa5f9f JA |
1013 | /* |
1014 | * Don't repeat dispatch from the previous queue. | |
1015 | */ | |
1016 | if (prev_cfqq == cfqq) | |
1017 | break; | |
1018 | ||
3b18152c JA |
1019 | cfq_clear_cfqq_must_dispatch(cfqq); |
1020 | cfq_clear_cfqq_wait_request(cfqq); | |
22e2c507 JA |
1021 | del_timer(&cfqd->idle_slice_timer); |
1022 | ||
1b5ed5e1 TH |
1023 | max_dispatch = cfqd->cfq_quantum; |
1024 | if (cfq_class_idle(cfqq)) | |
1025 | max_dispatch = 1; | |
1da177e4 | 1026 | |
caaa5f9f JA |
1027 | dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
1028 | ||
1029 | /* | |
1030 | * If the dispatch cfqq has idling enabled and is still | |
1031 | * the active queue, break out. | |
1032 | */ | |
1033 | if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue) | |
1034 | break; | |
1035 | ||
1036 | prev_cfqq = cfqq; | |
1da177e4 LT |
1037 | } |
1038 | ||
caaa5f9f | 1039 | return dispatched; |
1da177e4 LT |
1040 | } |
1041 | ||
1da177e4 LT |
1042 | /* |
1043 | * task holds one reference to the queue, dropped when task exits. each crq | |
1044 | * in-flight on this queue also holds a reference, dropped when crq is freed. | |
1045 | * | |
1046 | * queue lock must be held here. | |
1047 | */ | |
1048 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
1049 | { | |
22e2c507 JA |
1050 | struct cfq_data *cfqd = cfqq->cfqd; |
1051 | ||
1052 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
1053 | |
1054 | if (!atomic_dec_and_test(&cfqq->ref)) | |
1055 | return; | |
1056 | ||
1057 | BUG_ON(rb_first(&cfqq->sort_list)); | |
22e2c507 | 1058 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3b18152c | 1059 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 1060 | |
7b14e3b5 | 1061 | if (unlikely(cfqd->active_queue == cfqq)) |
3b18152c | 1062 | __cfq_slice_expired(cfqd, cfqq, 0); |
22e2c507 | 1063 | |
1da177e4 LT |
1064 | /* |
1065 | * it's on the empty list and still hashed | |
1066 | */ | |
1067 | list_del(&cfqq->cfq_list); | |
1068 | hlist_del(&cfqq->cfq_hash); | |
1069 | kmem_cache_free(cfq_pool, cfqq); | |
1070 | } | |
1071 | ||
1072 | static inline struct cfq_queue * | |
3b18152c JA |
1073 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, |
1074 | const int hashval) | |
1da177e4 LT |
1075 | { |
1076 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; | |
206dc69b JA |
1077 | struct hlist_node *entry; |
1078 | struct cfq_queue *__cfqq; | |
1da177e4 | 1079 | |
206dc69b | 1080 | hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) { |
b0a6916b | 1081 | const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio); |
1da177e4 | 1082 | |
206dc69b | 1083 | if (__cfqq->key == key && (__p == prio || !prio)) |
1da177e4 LT |
1084 | return __cfqq; |
1085 | } | |
1086 | ||
1087 | return NULL; | |
1088 | } | |
1089 | ||
1090 | static struct cfq_queue * | |
3b18152c | 1091 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) |
1da177e4 | 1092 | { |
3b18152c | 1093 | return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); |
1da177e4 LT |
1094 | } |
1095 | ||
e2d74ac0 | 1096 | static void cfq_free_io_context(struct io_context *ioc) |
1da177e4 | 1097 | { |
22e2c507 | 1098 | struct cfq_io_context *__cic; |
e2d74ac0 JA |
1099 | struct rb_node *n; |
1100 | int freed = 0; | |
1da177e4 | 1101 | |
e2d74ac0 JA |
1102 | while ((n = rb_first(&ioc->cic_root)) != NULL) { |
1103 | __cic = rb_entry(n, struct cfq_io_context, rb_node); | |
1104 | rb_erase(&__cic->rb_node, &ioc->cic_root); | |
22e2c507 | 1105 | kmem_cache_free(cfq_ioc_pool, __cic); |
334e94de | 1106 | freed++; |
1da177e4 LT |
1107 | } |
1108 | ||
334e94de AV |
1109 | if (atomic_sub_and_test(freed, &ioc_count) && ioc_gone) |
1110 | complete(ioc_gone); | |
1da177e4 LT |
1111 | } |
1112 | ||
e17a9489 AV |
1113 | static void cfq_trim(struct io_context *ioc) |
1114 | { | |
1115 | ioc->set_ioprio = NULL; | |
e2d74ac0 | 1116 | cfq_free_io_context(ioc); |
e17a9489 AV |
1117 | } |
1118 | ||
22e2c507 JA |
1119 | /* |
1120 | * Called with interrupts disabled | |
1121 | */ | |
1122 | static void cfq_exit_single_io_context(struct cfq_io_context *cic) | |
1da177e4 | 1123 | { |
478a82b0 | 1124 | struct cfq_data *cfqd = cic->key; |
d9ff4187 AV |
1125 | request_queue_t *q; |
1126 | ||
1127 | if (!cfqd) | |
1128 | return; | |
1129 | ||
1130 | q = cfqd->queue; | |
22e2c507 JA |
1131 | |
1132 | WARN_ON(!irqs_disabled()); | |
1133 | ||
1134 | spin_lock(q->queue_lock); | |
1135 | ||
12a05732 AV |
1136 | if (cic->cfqq[ASYNC]) { |
1137 | if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue)) | |
1138 | __cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0); | |
1139 | cfq_put_queue(cic->cfqq[ASYNC]); | |
1140 | cic->cfqq[ASYNC] = NULL; | |
1141 | } | |
1142 | ||
1143 | if (cic->cfqq[SYNC]) { | |
1144 | if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue)) | |
1145 | __cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0); | |
1146 | cfq_put_queue(cic->cfqq[SYNC]); | |
1147 | cic->cfqq[SYNC] = NULL; | |
1148 | } | |
22e2c507 | 1149 | |
478a82b0 | 1150 | cic->key = NULL; |
d9ff4187 | 1151 | list_del_init(&cic->queue_list); |
22e2c507 | 1152 | spin_unlock(q->queue_lock); |
1da177e4 LT |
1153 | } |
1154 | ||
e2d74ac0 | 1155 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 1156 | { |
22e2c507 | 1157 | struct cfq_io_context *__cic; |
1da177e4 | 1158 | unsigned long flags; |
e2d74ac0 | 1159 | struct rb_node *n; |
22e2c507 | 1160 | |
1da177e4 LT |
1161 | /* |
1162 | * put the reference this task is holding to the various queues | |
1163 | */ | |
3793c65c | 1164 | spin_lock_irqsave(&cfq_exit_lock, flags); |
e2d74ac0 JA |
1165 | |
1166 | n = rb_first(&ioc->cic_root); | |
1167 | while (n != NULL) { | |
1168 | __cic = rb_entry(n, struct cfq_io_context, rb_node); | |
1169 | ||
22e2c507 | 1170 | cfq_exit_single_io_context(__cic); |
e2d74ac0 | 1171 | n = rb_next(n); |
1da177e4 LT |
1172 | } |
1173 | ||
3793c65c | 1174 | spin_unlock_irqrestore(&cfq_exit_lock, flags); |
1da177e4 LT |
1175 | } |
1176 | ||
22e2c507 | 1177 | static struct cfq_io_context * |
8267e268 | 1178 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1179 | { |
22e2c507 | 1180 | struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); |
1da177e4 LT |
1181 | |
1182 | if (cic) { | |
553698f9 | 1183 | memset(cic, 0, sizeof(*cic)); |
22e2c507 | 1184 | cic->last_end_request = jiffies; |
553698f9 | 1185 | INIT_LIST_HEAD(&cic->queue_list); |
22e2c507 JA |
1186 | cic->dtor = cfq_free_io_context; |
1187 | cic->exit = cfq_exit_io_context; | |
334e94de | 1188 | atomic_inc(&ioc_count); |
1da177e4 LT |
1189 | } |
1190 | ||
1191 | return cic; | |
1192 | } | |
1193 | ||
22e2c507 JA |
1194 | static void cfq_init_prio_data(struct cfq_queue *cfqq) |
1195 | { | |
1196 | struct task_struct *tsk = current; | |
1197 | int ioprio_class; | |
1198 | ||
3b18152c | 1199 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
1200 | return; |
1201 | ||
1202 | ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); | |
1203 | switch (ioprio_class) { | |
1204 | default: | |
1205 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
1206 | case IOPRIO_CLASS_NONE: | |
1207 | /* | |
1208 | * no prio set, place us in the middle of the BE classes | |
1209 | */ | |
1210 | cfqq->ioprio = task_nice_ioprio(tsk); | |
1211 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1212 | break; | |
1213 | case IOPRIO_CLASS_RT: | |
1214 | cfqq->ioprio = task_ioprio(tsk); | |
1215 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
1216 | break; | |
1217 | case IOPRIO_CLASS_BE: | |
1218 | cfqq->ioprio = task_ioprio(tsk); | |
1219 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1220 | break; | |
1221 | case IOPRIO_CLASS_IDLE: | |
1222 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
1223 | cfqq->ioprio = 7; | |
3b18152c | 1224 | cfq_clear_cfqq_idle_window(cfqq); |
22e2c507 JA |
1225 | break; |
1226 | } | |
1227 | ||
1228 | /* | |
1229 | * keep track of original prio settings in case we have to temporarily | |
1230 | * elevate the priority of this queue | |
1231 | */ | |
1232 | cfqq->org_ioprio = cfqq->ioprio; | |
1233 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
1234 | ||
3b18152c | 1235 | if (cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1236 | cfq_resort_rr_list(cfqq, 0); |
1237 | ||
3b18152c | 1238 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
1239 | } |
1240 | ||
478a82b0 | 1241 | static inline void changed_ioprio(struct cfq_io_context *cic) |
22e2c507 | 1242 | { |
478a82b0 AV |
1243 | struct cfq_data *cfqd = cic->key; |
1244 | struct cfq_queue *cfqq; | |
35e6077c | 1245 | |
caaa5f9f JA |
1246 | if (unlikely(!cfqd)) |
1247 | return; | |
1248 | ||
1249 | spin_lock(cfqd->queue->queue_lock); | |
1250 | ||
1251 | cfqq = cic->cfqq[ASYNC]; | |
1252 | if (cfqq) { | |
1253 | struct cfq_queue *new_cfqq; | |
1254 | new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task, | |
1255 | GFP_ATOMIC); | |
1256 | if (new_cfqq) { | |
1257 | cic->cfqq[ASYNC] = new_cfqq; | |
1258 | cfq_put_queue(cfqq); | |
1259 | } | |
22e2c507 | 1260 | } |
caaa5f9f JA |
1261 | |
1262 | cfqq = cic->cfqq[SYNC]; | |
1263 | if (cfqq) | |
1264 | cfq_mark_cfqq_prio_changed(cfqq); | |
1265 | ||
1266 | spin_unlock(cfqd->queue->queue_lock); | |
22e2c507 JA |
1267 | } |
1268 | ||
1269 | /* | |
1270 | * callback from sys_ioprio_set, irqs are disabled | |
1271 | */ | |
1272 | static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) | |
1273 | { | |
a6a0763a | 1274 | struct cfq_io_context *cic; |
e2d74ac0 | 1275 | struct rb_node *n; |
a6a0763a | 1276 | |
3793c65c | 1277 | spin_lock(&cfq_exit_lock); |
a6a0763a | 1278 | |
e2d74ac0 JA |
1279 | n = rb_first(&ioc->cic_root); |
1280 | while (n != NULL) { | |
1281 | cic = rb_entry(n, struct cfq_io_context, rb_node); | |
3793c65c | 1282 | |
478a82b0 | 1283 | changed_ioprio(cic); |
e2d74ac0 JA |
1284 | n = rb_next(n); |
1285 | } | |
22e2c507 | 1286 | |
3793c65c | 1287 | spin_unlock(&cfq_exit_lock); |
a6a0763a | 1288 | |
22e2c507 JA |
1289 | return 0; |
1290 | } | |
1291 | ||
1292 | static struct cfq_queue * | |
6f325a13 | 1293 | cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, |
8267e268 | 1294 | gfp_t gfp_mask) |
22e2c507 JA |
1295 | { |
1296 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); | |
1297 | struct cfq_queue *cfqq, *new_cfqq = NULL; | |
6f325a13 | 1298 | unsigned short ioprio; |
22e2c507 JA |
1299 | |
1300 | retry: | |
6f325a13 | 1301 | ioprio = tsk->ioprio; |
3b18152c | 1302 | cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); |
22e2c507 JA |
1303 | |
1304 | if (!cfqq) { | |
1305 | if (new_cfqq) { | |
1306 | cfqq = new_cfqq; | |
1307 | new_cfqq = NULL; | |
1308 | } else if (gfp_mask & __GFP_WAIT) { | |
1309 | spin_unlock_irq(cfqd->queue->queue_lock); | |
1310 | new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1311 | spin_lock_irq(cfqd->queue->queue_lock); | |
1312 | goto retry; | |
1313 | } else { | |
1314 | cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1315 | if (!cfqq) | |
1316 | goto out; | |
1317 | } | |
1318 | ||
1319 | memset(cfqq, 0, sizeof(*cfqq)); | |
1320 | ||
1321 | INIT_HLIST_NODE(&cfqq->cfq_hash); | |
1322 | INIT_LIST_HEAD(&cfqq->cfq_list); | |
22e2c507 JA |
1323 | INIT_LIST_HEAD(&cfqq->fifo); |
1324 | ||
1325 | cfqq->key = key; | |
1326 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); | |
1327 | atomic_set(&cfqq->ref, 0); | |
1328 | cfqq->cfqd = cfqd; | |
22e2c507 JA |
1329 | cfqq->service_last = 0; |
1330 | /* | |
1331 | * set ->slice_left to allow preemption for a new process | |
1332 | */ | |
1333 | cfqq->slice_left = 2 * cfqd->cfq_slice_idle; | |
caaa5f9f | 1334 | cfq_mark_cfqq_idle_window(cfqq); |
3b18152c JA |
1335 | cfq_mark_cfqq_prio_changed(cfqq); |
1336 | cfq_init_prio_data(cfqq); | |
22e2c507 JA |
1337 | } |
1338 | ||
1339 | if (new_cfqq) | |
1340 | kmem_cache_free(cfq_pool, new_cfqq); | |
1341 | ||
1342 | atomic_inc(&cfqq->ref); | |
1343 | out: | |
1344 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); | |
1345 | return cfqq; | |
1346 | } | |
1347 | ||
dbecf3ab OH |
1348 | static void |
1349 | cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic) | |
1350 | { | |
3793c65c | 1351 | spin_lock(&cfq_exit_lock); |
dbecf3ab | 1352 | rb_erase(&cic->rb_node, &ioc->cic_root); |
3793c65c JA |
1353 | list_del_init(&cic->queue_list); |
1354 | spin_unlock(&cfq_exit_lock); | |
dbecf3ab OH |
1355 | kmem_cache_free(cfq_ioc_pool, cic); |
1356 | atomic_dec(&ioc_count); | |
1357 | } | |
1358 | ||
e2d74ac0 JA |
1359 | static struct cfq_io_context * |
1360 | cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc) | |
1361 | { | |
dbecf3ab | 1362 | struct rb_node *n; |
e2d74ac0 | 1363 | struct cfq_io_context *cic; |
be3b0753 | 1364 | void *k, *key = cfqd; |
e2d74ac0 | 1365 | |
dbecf3ab OH |
1366 | restart: |
1367 | n = ioc->cic_root.rb_node; | |
e2d74ac0 JA |
1368 | while (n) { |
1369 | cic = rb_entry(n, struct cfq_io_context, rb_node); | |
be3b0753 OH |
1370 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
1371 | k = cic->key; | |
1372 | if (unlikely(!k)) { | |
dbecf3ab OH |
1373 | cfq_drop_dead_cic(ioc, cic); |
1374 | goto restart; | |
1375 | } | |
e2d74ac0 | 1376 | |
be3b0753 | 1377 | if (key < k) |
e2d74ac0 | 1378 | n = n->rb_left; |
be3b0753 | 1379 | else if (key > k) |
e2d74ac0 JA |
1380 | n = n->rb_right; |
1381 | else | |
1382 | return cic; | |
1383 | } | |
1384 | ||
1385 | return NULL; | |
1386 | } | |
1387 | ||
1388 | static inline void | |
1389 | cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, | |
1390 | struct cfq_io_context *cic) | |
1391 | { | |
dbecf3ab OH |
1392 | struct rb_node **p; |
1393 | struct rb_node *parent; | |
e2d74ac0 | 1394 | struct cfq_io_context *__cic; |
be3b0753 | 1395 | void *k; |
e2d74ac0 | 1396 | |
e2d74ac0 JA |
1397 | cic->ioc = ioc; |
1398 | cic->key = cfqd; | |
1399 | ||
1400 | ioc->set_ioprio = cfq_ioc_set_ioprio; | |
dbecf3ab OH |
1401 | restart: |
1402 | parent = NULL; | |
1403 | p = &ioc->cic_root.rb_node; | |
e2d74ac0 JA |
1404 | while (*p) { |
1405 | parent = *p; | |
1406 | __cic = rb_entry(parent, struct cfq_io_context, rb_node); | |
be3b0753 OH |
1407 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
1408 | k = __cic->key; | |
1409 | if (unlikely(!k)) { | |
be33c3a6 | 1410 | cfq_drop_dead_cic(ioc, __cic); |
dbecf3ab OH |
1411 | goto restart; |
1412 | } | |
e2d74ac0 | 1413 | |
be3b0753 | 1414 | if (cic->key < k) |
e2d74ac0 | 1415 | p = &(*p)->rb_left; |
be3b0753 | 1416 | else if (cic->key > k) |
e2d74ac0 JA |
1417 | p = &(*p)->rb_right; |
1418 | else | |
1419 | BUG(); | |
1420 | } | |
1421 | ||
3793c65c | 1422 | spin_lock(&cfq_exit_lock); |
e2d74ac0 JA |
1423 | rb_link_node(&cic->rb_node, parent, p); |
1424 | rb_insert_color(&cic->rb_node, &ioc->cic_root); | |
1425 | list_add(&cic->queue_list, &cfqd->cic_list); | |
3793c65c | 1426 | spin_unlock(&cfq_exit_lock); |
e2d74ac0 JA |
1427 | } |
1428 | ||
1da177e4 LT |
1429 | /* |
1430 | * Setup general io context and cfq io context. There can be several cfq | |
1431 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 1432 | * than one device managed by cfq. |
1da177e4 LT |
1433 | */ |
1434 | static struct cfq_io_context * | |
e2d74ac0 | 1435 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1436 | { |
22e2c507 | 1437 | struct io_context *ioc = NULL; |
1da177e4 | 1438 | struct cfq_io_context *cic; |
1da177e4 | 1439 | |
22e2c507 | 1440 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 1441 | |
22e2c507 | 1442 | ioc = get_io_context(gfp_mask); |
1da177e4 LT |
1443 | if (!ioc) |
1444 | return NULL; | |
1445 | ||
e2d74ac0 JA |
1446 | cic = cfq_cic_rb_lookup(cfqd, ioc); |
1447 | if (cic) | |
1448 | goto out; | |
1da177e4 | 1449 | |
e2d74ac0 JA |
1450 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1451 | if (cic == NULL) | |
1452 | goto err; | |
1da177e4 | 1453 | |
e2d74ac0 | 1454 | cfq_cic_link(cfqd, ioc, cic); |
1da177e4 | 1455 | out: |
1da177e4 LT |
1456 | return cic; |
1457 | err: | |
1458 | put_io_context(ioc); | |
1459 | return NULL; | |
1460 | } | |
1461 | ||
22e2c507 JA |
1462 | static void |
1463 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 1464 | { |
22e2c507 | 1465 | unsigned long elapsed, ttime; |
1da177e4 | 1466 | |
22e2c507 JA |
1467 | /* |
1468 | * if this context already has stuff queued, thinktime is from | |
1469 | * last queue not last end | |
1470 | */ | |
1471 | #if 0 | |
1472 | if (time_after(cic->last_end_request, cic->last_queue)) | |
1473 | elapsed = jiffies - cic->last_end_request; | |
1474 | else | |
1475 | elapsed = jiffies - cic->last_queue; | |
1476 | #else | |
1477 | elapsed = jiffies - cic->last_end_request; | |
1478 | #endif | |
1da177e4 | 1479 | |
22e2c507 | 1480 | ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
db3b5848 | 1481 | |
22e2c507 JA |
1482 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
1483 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
1484 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
1485 | } | |
1da177e4 | 1486 | |
206dc69b JA |
1487 | static void |
1488 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
1489 | struct cfq_rq *crq) | |
1490 | { | |
1491 | sector_t sdist; | |
1492 | u64 total; | |
1493 | ||
1494 | if (cic->last_request_pos < crq->request->sector) | |
1495 | sdist = crq->request->sector - cic->last_request_pos; | |
1496 | else | |
1497 | sdist = cic->last_request_pos - crq->request->sector; | |
1498 | ||
1499 | /* | |
1500 | * Don't allow the seek distance to get too large from the | |
1501 | * odd fragment, pagein, etc | |
1502 | */ | |
1503 | if (cic->seek_samples <= 60) /* second&third seek */ | |
1504 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024); | |
1505 | else | |
1506 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64); | |
1507 | ||
1508 | cic->seek_samples = (7*cic->seek_samples + 256) / 8; | |
1509 | cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8; | |
1510 | total = cic->seek_total + (cic->seek_samples/2); | |
1511 | do_div(total, cic->seek_samples); | |
1512 | cic->seek_mean = (sector_t)total; | |
1513 | } | |
1da177e4 | 1514 | |
22e2c507 JA |
1515 | /* |
1516 | * Disable idle window if the process thinks too long or seeks so much that | |
1517 | * it doesn't matter | |
1518 | */ | |
1519 | static void | |
1520 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1521 | struct cfq_io_context *cic) | |
1522 | { | |
3b18152c | 1523 | int enable_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 1524 | |
caaa5f9f JA |
1525 | if (!cic->ioc->task || !cfqd->cfq_slice_idle || |
1526 | (cfqd->hw_tag && CIC_SEEKY(cic))) | |
22e2c507 JA |
1527 | enable_idle = 0; |
1528 | else if (sample_valid(cic->ttime_samples)) { | |
1529 | if (cic->ttime_mean > cfqd->cfq_slice_idle) | |
1530 | enable_idle = 0; | |
1531 | else | |
1532 | enable_idle = 1; | |
1da177e4 LT |
1533 | } |
1534 | ||
3b18152c JA |
1535 | if (enable_idle) |
1536 | cfq_mark_cfqq_idle_window(cfqq); | |
1537 | else | |
1538 | cfq_clear_cfqq_idle_window(cfqq); | |
22e2c507 | 1539 | } |
1da177e4 | 1540 | |
22e2c507 JA |
1541 | |
1542 | /* | |
1543 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
1544 | * no or if we aren't sure, a 1 will cause a preempt. | |
1545 | */ | |
1546 | static int | |
1547 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, | |
1548 | struct cfq_rq *crq) | |
1549 | { | |
1550 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1551 | ||
1552 | if (cfq_class_idle(new_cfqq)) | |
1553 | return 0; | |
1554 | ||
1555 | if (!cfqq) | |
caaa5f9f | 1556 | return 0; |
22e2c507 JA |
1557 | |
1558 | if (cfq_class_idle(cfqq)) | |
1559 | return 1; | |
3b18152c | 1560 | if (!cfq_cfqq_wait_request(new_cfqq)) |
22e2c507 JA |
1561 | return 0; |
1562 | /* | |
1563 | * if it doesn't have slice left, forget it | |
1564 | */ | |
1565 | if (new_cfqq->slice_left < cfqd->cfq_slice_idle) | |
1566 | return 0; | |
5380a101 | 1567 | if (rq_is_sync(crq->request) && !cfq_cfqq_sync(cfqq)) |
22e2c507 JA |
1568 | return 1; |
1569 | ||
1570 | return 0; | |
1571 | } | |
1572 | ||
1573 | /* | |
1574 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
1575 | * let it have half of its nominal slice. | |
1576 | */ | |
1577 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1578 | { | |
1579 | struct cfq_queue *__cfqq, *next; | |
1580 | ||
1581 | list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) | |
1582 | cfq_resort_rr_list(__cfqq, 1); | |
1583 | ||
1584 | if (!cfqq->slice_left) | |
1585 | cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; | |
1586 | ||
1587 | cfqq->slice_end = cfqq->slice_left + jiffies; | |
caaa5f9f | 1588 | cfq_slice_expired(cfqd, 1); |
22e2c507 JA |
1589 | __cfq_set_active_queue(cfqd, cfqq); |
1590 | } | |
1591 | ||
1592 | /* | |
1593 | * should really be a ll_rw_blk.c helper | |
1594 | */ | |
1595 | static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1596 | { | |
1597 | request_queue_t *q = cfqd->queue; | |
1598 | ||
1599 | if (!blk_queue_plugged(q)) | |
1600 | q->request_fn(q); | |
1601 | else | |
1602 | __generic_unplug_device(q); | |
1603 | } | |
1604 | ||
1605 | /* | |
1606 | * Called when a new fs request (crq) is added (to cfqq). Check if there's | |
1607 | * something we should do about it | |
1608 | */ | |
1609 | static void | |
1610 | cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1611 | struct cfq_rq *crq) | |
1612 | { | |
fd61af03 | 1613 | struct cfq_io_context *cic = crq->io_context; |
12e9fddd | 1614 | |
21183b07 | 1615 | /* |
5380a101 | 1616 | * check if this request is a better next-serve candidate)) { |
21183b07 JA |
1617 | */ |
1618 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
1619 | BUG_ON(!cfqq->next_crq); | |
1620 | ||
9c2c38a1 JA |
1621 | /* |
1622 | * we never wait for an async request and we don't allow preemption | |
1623 | * of an async request. so just return early | |
1624 | */ | |
5380a101 | 1625 | if (!rq_is_sync(crq->request)) { |
12e9fddd JA |
1626 | /* |
1627 | * sync process issued an async request, if it's waiting | |
1628 | * then expire it and kick rq handling. | |
1629 | */ | |
1630 | if (cic == cfqd->active_cic && | |
1631 | del_timer(&cfqd->idle_slice_timer)) { | |
1632 | cfq_slice_expired(cfqd, 0); | |
1633 | cfq_start_queueing(cfqd, cfqq); | |
1634 | } | |
9c2c38a1 | 1635 | return; |
12e9fddd | 1636 | } |
22e2c507 | 1637 | |
9c2c38a1 | 1638 | cfq_update_io_thinktime(cfqd, cic); |
206dc69b | 1639 | cfq_update_io_seektime(cfqd, cic, crq); |
9c2c38a1 JA |
1640 | cfq_update_idle_window(cfqd, cfqq, cic); |
1641 | ||
1642 | cic->last_queue = jiffies; | |
206dc69b | 1643 | cic->last_request_pos = crq->request->sector + crq->request->nr_sectors; |
22e2c507 JA |
1644 | |
1645 | if (cfqq == cfqd->active_queue) { | |
1646 | /* | |
1647 | * if we are waiting for a request for this queue, let it rip | |
1648 | * immediately and flag that we must not expire this queue | |
1649 | * just now | |
1650 | */ | |
3b18152c JA |
1651 | if (cfq_cfqq_wait_request(cfqq)) { |
1652 | cfq_mark_cfqq_must_dispatch(cfqq); | |
22e2c507 JA |
1653 | del_timer(&cfqd->idle_slice_timer); |
1654 | cfq_start_queueing(cfqd, cfqq); | |
1655 | } | |
1656 | } else if (cfq_should_preempt(cfqd, cfqq, crq)) { | |
1657 | /* | |
1658 | * not the active queue - expire current slice if it is | |
1659 | * idle and has expired it's mean thinktime or this new queue | |
1660 | * has some old slice time left and is of higher priority | |
1661 | */ | |
1662 | cfq_preempt_queue(cfqd, cfqq); | |
3b18152c | 1663 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
1664 | cfq_start_queueing(cfqd, cfqq); |
1665 | } | |
1da177e4 LT |
1666 | } |
1667 | ||
b4878f24 | 1668 | static void cfq_insert_request(request_queue_t *q, struct request *rq) |
1da177e4 | 1669 | { |
b4878f24 | 1670 | struct cfq_data *cfqd = q->elevator->elevator_data; |
22e2c507 JA |
1671 | struct cfq_rq *crq = RQ_DATA(rq); |
1672 | struct cfq_queue *cfqq = crq->cfq_queue; | |
1673 | ||
1674 | cfq_init_prio_data(cfqq); | |
1da177e4 LT |
1675 | |
1676 | cfq_add_crq_rb(crq); | |
1da177e4 | 1677 | |
21183b07 JA |
1678 | if (!cfq_cfqq_on_rr(cfqq)) |
1679 | cfq_add_cfqq_rr(cfqd, cfqq); | |
1680 | ||
22e2c507 JA |
1681 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
1682 | ||
22e2c507 | 1683 | cfq_crq_enqueued(cfqd, cfqq, crq); |
1da177e4 LT |
1684 | } |
1685 | ||
1da177e4 LT |
1686 | static void cfq_completed_request(request_queue_t *q, struct request *rq) |
1687 | { | |
1688 | struct cfq_rq *crq = RQ_DATA(rq); | |
b4878f24 JA |
1689 | struct cfq_queue *cfqq = crq->cfq_queue; |
1690 | struct cfq_data *cfqd = cfqq->cfqd; | |
5380a101 | 1691 | const int sync = rq_is_sync(rq); |
b4878f24 | 1692 | unsigned long now; |
1da177e4 | 1693 | |
b4878f24 | 1694 | now = jiffies; |
1da177e4 | 1695 | |
b4878f24 JA |
1696 | WARN_ON(!cfqd->rq_in_driver); |
1697 | WARN_ON(!cfqq->on_dispatch[sync]); | |
1698 | cfqd->rq_in_driver--; | |
1699 | cfqq->on_dispatch[sync]--; | |
1da177e4 | 1700 | |
b4878f24 JA |
1701 | if (!cfq_class_idle(cfqq)) |
1702 | cfqd->last_end_request = now; | |
3b18152c | 1703 | |
b4878f24 JA |
1704 | if (!cfq_cfqq_dispatched(cfqq)) { |
1705 | if (cfq_cfqq_on_rr(cfqq)) { | |
1706 | cfqq->service_last = now; | |
1707 | cfq_resort_rr_list(cfqq, 0); | |
1708 | } | |
1da177e4 LT |
1709 | } |
1710 | ||
caaa5f9f | 1711 | if (sync) |
b4878f24 | 1712 | crq->io_context->last_end_request = now; |
caaa5f9f JA |
1713 | |
1714 | /* | |
1715 | * If this is the active queue, check if it needs to be expired, | |
1716 | * or if we want to idle in case it has no pending requests. | |
1717 | */ | |
1718 | if (cfqd->active_queue == cfqq) { | |
1719 | if (time_after(now, cfqq->slice_end)) | |
1720 | cfq_slice_expired(cfqd, 0); | |
dd67d051 | 1721 | else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
caaa5f9f JA |
1722 | if (!cfq_arm_slice_timer(cfqd, cfqq)) |
1723 | cfq_schedule_dispatch(cfqd); | |
1724 | } | |
1725 | } | |
1da177e4 LT |
1726 | } |
1727 | ||
22e2c507 JA |
1728 | /* |
1729 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
1730 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
1731 | */ | |
1732 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 1733 | { |
22e2c507 JA |
1734 | const int ioprio_class = cfqq->ioprio_class; |
1735 | const int ioprio = cfqq->ioprio; | |
1da177e4 | 1736 | |
22e2c507 JA |
1737 | if (has_fs_excl()) { |
1738 | /* | |
1739 | * boost idle prio on transactions that would lock out other | |
1740 | * users of the filesystem | |
1741 | */ | |
1742 | if (cfq_class_idle(cfqq)) | |
1743 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1744 | if (cfqq->ioprio > IOPRIO_NORM) | |
1745 | cfqq->ioprio = IOPRIO_NORM; | |
1746 | } else { | |
1747 | /* | |
1748 | * check if we need to unboost the queue | |
1749 | */ | |
1750 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) | |
1751 | cfqq->ioprio_class = cfqq->org_ioprio_class; | |
1752 | if (cfqq->ioprio != cfqq->org_ioprio) | |
1753 | cfqq->ioprio = cfqq->org_ioprio; | |
1754 | } | |
1da177e4 | 1755 | |
22e2c507 JA |
1756 | /* |
1757 | * refile between round-robin lists if we moved the priority class | |
1758 | */ | |
1759 | if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && | |
3b18152c | 1760 | cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1761 | cfq_resort_rr_list(cfqq, 0); |
1762 | } | |
1da177e4 | 1763 | |
22e2c507 JA |
1764 | static inline int |
1765 | __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1766 | struct task_struct *task, int rw) | |
1767 | { | |
3b18152c | 1768 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && |
99f95e52 | 1769 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1770 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1771 | return ELV_MQUEUE_MUST; |
3b18152c | 1772 | } |
1da177e4 | 1773 | |
22e2c507 | 1774 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
1775 | } |
1776 | ||
1777 | static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) | |
1778 | { | |
1779 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1780 | struct task_struct *tsk = current; | |
1781 | struct cfq_queue *cfqq; | |
1782 | ||
1783 | /* | |
1784 | * don't force setup of a queue from here, as a call to may_queue | |
1785 | * does not necessarily imply that a request actually will be queued. | |
1786 | * so just lookup a possibly existing queue, or return 'may queue' | |
1787 | * if that fails | |
1788 | */ | |
3b18152c | 1789 | cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); |
22e2c507 JA |
1790 | if (cfqq) { |
1791 | cfq_init_prio_data(cfqq); | |
1792 | cfq_prio_boost(cfqq); | |
1793 | ||
1794 | return __cfq_may_queue(cfqd, cfqq, tsk, rw); | |
1795 | } | |
1796 | ||
1797 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
1798 | } |
1799 | ||
1800 | static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) | |
1801 | { | |
22e2c507 | 1802 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1da177e4 | 1803 | |
271f18f1 JA |
1804 | if (unlikely(cfqd->rq_starved)) { |
1805 | struct request_list *rl = &q->rq; | |
1806 | ||
22e2c507 JA |
1807 | smp_mb(); |
1808 | if (waitqueue_active(&rl->wait[READ])) | |
1809 | wake_up(&rl->wait[READ]); | |
22e2c507 JA |
1810 | if (waitqueue_active(&rl->wait[WRITE])) |
1811 | wake_up(&rl->wait[WRITE]); | |
1812 | } | |
1da177e4 LT |
1813 | } |
1814 | ||
1815 | /* | |
1816 | * queue lock held here | |
1817 | */ | |
1818 | static void cfq_put_request(request_queue_t *q, struct request *rq) | |
1819 | { | |
1820 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1821 | struct cfq_rq *crq = RQ_DATA(rq); | |
1822 | ||
1823 | if (crq) { | |
1824 | struct cfq_queue *cfqq = crq->cfq_queue; | |
22e2c507 | 1825 | const int rw = rq_data_dir(rq); |
1da177e4 | 1826 | |
22e2c507 JA |
1827 | BUG_ON(!cfqq->allocated[rw]); |
1828 | cfqq->allocated[rw]--; | |
1da177e4 | 1829 | |
22e2c507 | 1830 | put_io_context(crq->io_context->ioc); |
1da177e4 LT |
1831 | |
1832 | mempool_free(crq, cfqd->crq_pool); | |
1833 | rq->elevator_private = NULL; | |
1834 | ||
1da177e4 LT |
1835 | cfq_check_waiters(q, cfqq); |
1836 | cfq_put_queue(cfqq); | |
1837 | } | |
1838 | } | |
1839 | ||
1840 | /* | |
22e2c507 | 1841 | * Allocate cfq data structures associated with this request. |
1da177e4 | 1842 | */ |
22e2c507 JA |
1843 | static int |
1844 | cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, | |
8267e268 | 1845 | gfp_t gfp_mask) |
1da177e4 LT |
1846 | { |
1847 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3b18152c | 1848 | struct task_struct *tsk = current; |
1da177e4 LT |
1849 | struct cfq_io_context *cic; |
1850 | const int rw = rq_data_dir(rq); | |
3b18152c | 1851 | pid_t key = cfq_queue_pid(tsk, rw); |
22e2c507 | 1852 | struct cfq_queue *cfqq; |
1da177e4 LT |
1853 | struct cfq_rq *crq; |
1854 | unsigned long flags; | |
12a05732 | 1855 | int is_sync = key != CFQ_KEY_ASYNC; |
1da177e4 LT |
1856 | |
1857 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
1858 | ||
e2d74ac0 | 1859 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 1860 | |
1da177e4 LT |
1861 | spin_lock_irqsave(q->queue_lock, flags); |
1862 | ||
22e2c507 JA |
1863 | if (!cic) |
1864 | goto queue_fail; | |
1865 | ||
12a05732 | 1866 | if (!cic->cfqq[is_sync]) { |
6f325a13 | 1867 | cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask); |
22e2c507 JA |
1868 | if (!cfqq) |
1869 | goto queue_fail; | |
1da177e4 | 1870 | |
12a05732 | 1871 | cic->cfqq[is_sync] = cfqq; |
22e2c507 | 1872 | } else |
12a05732 | 1873 | cfqq = cic->cfqq[is_sync]; |
1da177e4 LT |
1874 | |
1875 | cfqq->allocated[rw]++; | |
3b18152c | 1876 | cfq_clear_cfqq_must_alloc(cfqq); |
22e2c507 JA |
1877 | cfqd->rq_starved = 0; |
1878 | atomic_inc(&cfqq->ref); | |
1da177e4 LT |
1879 | spin_unlock_irqrestore(q->queue_lock, flags); |
1880 | ||
1da177e4 LT |
1881 | crq = mempool_alloc(cfqd->crq_pool, gfp_mask); |
1882 | if (crq) { | |
1da177e4 | 1883 | crq->request = rq; |
1da177e4 LT |
1884 | crq->cfq_queue = cfqq; |
1885 | crq->io_context = cic; | |
3b18152c | 1886 | |
1da177e4 | 1887 | rq->elevator_private = crq; |
1da177e4 LT |
1888 | return 0; |
1889 | } | |
1890 | ||
1da177e4 LT |
1891 | spin_lock_irqsave(q->queue_lock, flags); |
1892 | cfqq->allocated[rw]--; | |
22e2c507 | 1893 | if (!(cfqq->allocated[0] + cfqq->allocated[1])) |
3b18152c | 1894 | cfq_mark_cfqq_must_alloc(cfqq); |
1da177e4 | 1895 | cfq_put_queue(cfqq); |
22e2c507 JA |
1896 | queue_fail: |
1897 | if (cic) | |
1898 | put_io_context(cic->ioc); | |
1899 | /* | |
1900 | * mark us rq allocation starved. we need to kickstart the process | |
1901 | * ourselves if there are no pending requests that can do it for us. | |
1902 | * that would be an extremely rare OOM situation | |
1903 | */ | |
1904 | cfqd->rq_starved = 1; | |
3b18152c | 1905 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
1906 | spin_unlock_irqrestore(q->queue_lock, flags); |
1907 | return 1; | |
1908 | } | |
1909 | ||
22e2c507 JA |
1910 | static void cfq_kick_queue(void *data) |
1911 | { | |
1912 | request_queue_t *q = data; | |
1913 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1914 | unsigned long flags; | |
1915 | ||
1916 | spin_lock_irqsave(q->queue_lock, flags); | |
1917 | ||
1918 | if (cfqd->rq_starved) { | |
1919 | struct request_list *rl = &q->rq; | |
1920 | ||
1921 | /* | |
1922 | * we aren't guaranteed to get a request after this, but we | |
1923 | * have to be opportunistic | |
1924 | */ | |
1925 | smp_mb(); | |
1926 | if (waitqueue_active(&rl->wait[READ])) | |
1927 | wake_up(&rl->wait[READ]); | |
1928 | if (waitqueue_active(&rl->wait[WRITE])) | |
1929 | wake_up(&rl->wait[WRITE]); | |
1930 | } | |
1931 | ||
1932 | blk_remove_plug(q); | |
1933 | q->request_fn(q); | |
1934 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1935 | } | |
1936 | ||
1937 | /* | |
1938 | * Timer running if the active_queue is currently idling inside its time slice | |
1939 | */ | |
1940 | static void cfq_idle_slice_timer(unsigned long data) | |
1941 | { | |
1942 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
1943 | struct cfq_queue *cfqq; | |
1944 | unsigned long flags; | |
1945 | ||
1946 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1947 | ||
1948 | if ((cfqq = cfqd->active_queue) != NULL) { | |
1949 | unsigned long now = jiffies; | |
1950 | ||
1951 | /* | |
1952 | * expired | |
1953 | */ | |
1954 | if (time_after(now, cfqq->slice_end)) | |
1955 | goto expire; | |
1956 | ||
1957 | /* | |
1958 | * only expire and reinvoke request handler, if there are | |
1959 | * other queues with pending requests | |
1960 | */ | |
caaa5f9f | 1961 | if (!cfqd->busy_queues) |
22e2c507 | 1962 | goto out_cont; |
22e2c507 JA |
1963 | |
1964 | /* | |
1965 | * not expired and it has a request pending, let it dispatch | |
1966 | */ | |
dd67d051 | 1967 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) { |
3b18152c | 1968 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
1969 | goto out_kick; |
1970 | } | |
1971 | } | |
1972 | expire: | |
1973 | cfq_slice_expired(cfqd, 0); | |
1974 | out_kick: | |
3b18152c | 1975 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
1976 | out_cont: |
1977 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1978 | } | |
1979 | ||
1980 | /* | |
1981 | * Timer running if an idle class queue is waiting for service | |
1982 | */ | |
1983 | static void cfq_idle_class_timer(unsigned long data) | |
1984 | { | |
1985 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
1986 | unsigned long flags, end; | |
1987 | ||
1988 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1989 | ||
1990 | /* | |
1991 | * race with a non-idle queue, reset timer | |
1992 | */ | |
1993 | end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
ae818a38 JA |
1994 | if (!time_after_eq(jiffies, end)) |
1995 | mod_timer(&cfqd->idle_class_timer, end); | |
1996 | else | |
3b18152c | 1997 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
1998 | |
1999 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2000 | } | |
2001 | ||
3b18152c JA |
2002 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
2003 | { | |
2004 | del_timer_sync(&cfqd->idle_slice_timer); | |
2005 | del_timer_sync(&cfqd->idle_class_timer); | |
2006 | blk_sync_queue(cfqd->queue); | |
2007 | } | |
22e2c507 | 2008 | |
1da177e4 LT |
2009 | static void cfq_exit_queue(elevator_t *e) |
2010 | { | |
22e2c507 | 2011 | struct cfq_data *cfqd = e->elevator_data; |
d9ff4187 | 2012 | request_queue_t *q = cfqd->queue; |
22e2c507 | 2013 | |
3b18152c | 2014 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 2015 | |
3793c65c | 2016 | spin_lock(&cfq_exit_lock); |
d9ff4187 | 2017 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 2018 | |
d9ff4187 AV |
2019 | if (cfqd->active_queue) |
2020 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); | |
e2d74ac0 JA |
2021 | |
2022 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
2023 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
2024 | struct cfq_io_context, | |
2025 | queue_list); | |
2026 | if (cic->cfqq[ASYNC]) { | |
2027 | cfq_put_queue(cic->cfqq[ASYNC]); | |
2028 | cic->cfqq[ASYNC] = NULL; | |
2029 | } | |
2030 | if (cic->cfqq[SYNC]) { | |
2031 | cfq_put_queue(cic->cfqq[SYNC]); | |
2032 | cic->cfqq[SYNC] = NULL; | |
2033 | } | |
2034 | cic->key = NULL; | |
2035 | list_del_init(&cic->queue_list); | |
2036 | } | |
e2d74ac0 | 2037 | |
d9ff4187 | 2038 | spin_unlock_irq(q->queue_lock); |
3793c65c | 2039 | spin_unlock(&cfq_exit_lock); |
a90d742e AV |
2040 | |
2041 | cfq_shutdown_timer_wq(cfqd); | |
2042 | ||
2043 | mempool_destroy(cfqd->crq_pool); | |
a90d742e AV |
2044 | kfree(cfqd->cfq_hash); |
2045 | kfree(cfqd); | |
1da177e4 LT |
2046 | } |
2047 | ||
bc1c1169 | 2048 | static void *cfq_init_queue(request_queue_t *q, elevator_t *e) |
1da177e4 LT |
2049 | { |
2050 | struct cfq_data *cfqd; | |
2051 | int i; | |
2052 | ||
2053 | cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); | |
2054 | if (!cfqd) | |
bc1c1169 | 2055 | return NULL; |
1da177e4 LT |
2056 | |
2057 | memset(cfqd, 0, sizeof(*cfqd)); | |
22e2c507 JA |
2058 | |
2059 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
2060 | INIT_LIST_HEAD(&cfqd->rr_list[i]); | |
2061 | ||
2062 | INIT_LIST_HEAD(&cfqd->busy_rr); | |
2063 | INIT_LIST_HEAD(&cfqd->cur_rr); | |
2064 | INIT_LIST_HEAD(&cfqd->idle_rr); | |
1da177e4 | 2065 | INIT_LIST_HEAD(&cfqd->empty_list); |
d9ff4187 | 2066 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 2067 | |
1da177e4 LT |
2068 | cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); |
2069 | if (!cfqd->cfq_hash) | |
9817064b | 2070 | goto out_crqhash; |
1da177e4 | 2071 | |
93d2341c | 2072 | cfqd->crq_pool = mempool_create_slab_pool(BLKDEV_MIN_RQ, crq_pool); |
1da177e4 LT |
2073 | if (!cfqd->crq_pool) |
2074 | goto out_crqpool; | |
2075 | ||
1da177e4 LT |
2076 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) |
2077 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); | |
2078 | ||
1da177e4 | 2079 | cfqd->queue = q; |
1da177e4 | 2080 | |
22e2c507 JA |
2081 | init_timer(&cfqd->idle_slice_timer); |
2082 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
2083 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
2084 | ||
2085 | init_timer(&cfqd->idle_class_timer); | |
2086 | cfqd->idle_class_timer.function = cfq_idle_class_timer; | |
2087 | cfqd->idle_class_timer.data = (unsigned long) cfqd; | |
2088 | ||
2089 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); | |
2090 | ||
1da177e4 LT |
2091 | cfqd->cfq_queued = cfq_queued; |
2092 | cfqd->cfq_quantum = cfq_quantum; | |
22e2c507 JA |
2093 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
2094 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
2095 | cfqd->cfq_back_max = cfq_back_max; |
2096 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
2097 | cfqd->cfq_slice[0] = cfq_slice_async; |
2098 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
2099 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
2100 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
3b18152c | 2101 | |
bc1c1169 | 2102 | return cfqd; |
1da177e4 LT |
2103 | out_crqpool: |
2104 | kfree(cfqd->cfq_hash); | |
1da177e4 LT |
2105 | out_crqhash: |
2106 | kfree(cfqd); | |
bc1c1169 | 2107 | return NULL; |
1da177e4 LT |
2108 | } |
2109 | ||
2110 | static void cfq_slab_kill(void) | |
2111 | { | |
2112 | if (crq_pool) | |
2113 | kmem_cache_destroy(crq_pool); | |
2114 | if (cfq_pool) | |
2115 | kmem_cache_destroy(cfq_pool); | |
2116 | if (cfq_ioc_pool) | |
2117 | kmem_cache_destroy(cfq_ioc_pool); | |
2118 | } | |
2119 | ||
2120 | static int __init cfq_slab_setup(void) | |
2121 | { | |
2122 | crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, | |
2123 | NULL, NULL); | |
2124 | if (!crq_pool) | |
2125 | goto fail; | |
2126 | ||
2127 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, | |
2128 | NULL, NULL); | |
2129 | if (!cfq_pool) | |
2130 | goto fail; | |
2131 | ||
2132 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", | |
2133 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); | |
2134 | if (!cfq_ioc_pool) | |
2135 | goto fail; | |
2136 | ||
2137 | return 0; | |
2138 | fail: | |
2139 | cfq_slab_kill(); | |
2140 | return -ENOMEM; | |
2141 | } | |
2142 | ||
1da177e4 LT |
2143 | /* |
2144 | * sysfs parts below --> | |
2145 | */ | |
1da177e4 LT |
2146 | |
2147 | static ssize_t | |
2148 | cfq_var_show(unsigned int var, char *page) | |
2149 | { | |
2150 | return sprintf(page, "%d\n", var); | |
2151 | } | |
2152 | ||
2153 | static ssize_t | |
2154 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
2155 | { | |
2156 | char *p = (char *) page; | |
2157 | ||
2158 | *var = simple_strtoul(p, &p, 10); | |
2159 | return count; | |
2160 | } | |
2161 | ||
1da177e4 | 2162 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
3d1ab40f | 2163 | static ssize_t __FUNC(elevator_t *e, char *page) \ |
1da177e4 | 2164 | { \ |
3d1ab40f | 2165 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
2166 | unsigned int __data = __VAR; \ |
2167 | if (__CONV) \ | |
2168 | __data = jiffies_to_msecs(__data); \ | |
2169 | return cfq_var_show(__data, (page)); \ | |
2170 | } | |
2171 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
2172 | SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); | |
22e2c507 JA |
2173 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
2174 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
2175 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
2176 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
2177 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
2178 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
2179 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
2180 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
1da177e4 LT |
2181 | #undef SHOW_FUNCTION |
2182 | ||
2183 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
3d1ab40f | 2184 | static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ |
1da177e4 | 2185 | { \ |
3d1ab40f | 2186 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
2187 | unsigned int __data; \ |
2188 | int ret = cfq_var_store(&__data, (page), count); \ | |
2189 | if (__data < (MIN)) \ | |
2190 | __data = (MIN); \ | |
2191 | else if (__data > (MAX)) \ | |
2192 | __data = (MAX); \ | |
2193 | if (__CONV) \ | |
2194 | *(__PTR) = msecs_to_jiffies(__data); \ | |
2195 | else \ | |
2196 | *(__PTR) = __data; \ | |
2197 | return ret; \ | |
2198 | } | |
2199 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
2200 | STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); | |
22e2c507 JA |
2201 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); |
2202 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); | |
e572ec7e AV |
2203 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
2204 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); | |
22e2c507 JA |
2205 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
2206 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
2207 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
2208 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); | |
1da177e4 LT |
2209 | #undef STORE_FUNCTION |
2210 | ||
e572ec7e AV |
2211 | #define CFQ_ATTR(name) \ |
2212 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
2213 | ||
2214 | static struct elv_fs_entry cfq_attrs[] = { | |
2215 | CFQ_ATTR(quantum), | |
2216 | CFQ_ATTR(queued), | |
2217 | CFQ_ATTR(fifo_expire_sync), | |
2218 | CFQ_ATTR(fifo_expire_async), | |
2219 | CFQ_ATTR(back_seek_max), | |
2220 | CFQ_ATTR(back_seek_penalty), | |
2221 | CFQ_ATTR(slice_sync), | |
2222 | CFQ_ATTR(slice_async), | |
2223 | CFQ_ATTR(slice_async_rq), | |
2224 | CFQ_ATTR(slice_idle), | |
e572ec7e | 2225 | __ATTR_NULL |
1da177e4 LT |
2226 | }; |
2227 | ||
1da177e4 LT |
2228 | static struct elevator_type iosched_cfq = { |
2229 | .ops = { | |
2230 | .elevator_merge_fn = cfq_merge, | |
2231 | .elevator_merged_fn = cfq_merged_request, | |
2232 | .elevator_merge_req_fn = cfq_merged_requests, | |
b4878f24 | 2233 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 2234 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 2235 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
2236 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
2237 | .elevator_queue_empty_fn = cfq_queue_empty, | |
2238 | .elevator_completed_req_fn = cfq_completed_request, | |
21183b07 JA |
2239 | .elevator_former_req_fn = elv_rb_former_request, |
2240 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
2241 | .elevator_set_req_fn = cfq_set_request, |
2242 | .elevator_put_req_fn = cfq_put_request, | |
2243 | .elevator_may_queue_fn = cfq_may_queue, | |
2244 | .elevator_init_fn = cfq_init_queue, | |
2245 | .elevator_exit_fn = cfq_exit_queue, | |
e17a9489 | 2246 | .trim = cfq_trim, |
1da177e4 | 2247 | }, |
3d1ab40f | 2248 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
2249 | .elevator_name = "cfq", |
2250 | .elevator_owner = THIS_MODULE, | |
2251 | }; | |
2252 | ||
2253 | static int __init cfq_init(void) | |
2254 | { | |
2255 | int ret; | |
2256 | ||
22e2c507 JA |
2257 | /* |
2258 | * could be 0 on HZ < 1000 setups | |
2259 | */ | |
2260 | if (!cfq_slice_async) | |
2261 | cfq_slice_async = 1; | |
2262 | if (!cfq_slice_idle) | |
2263 | cfq_slice_idle = 1; | |
2264 | ||
1da177e4 LT |
2265 | if (cfq_slab_setup()) |
2266 | return -ENOMEM; | |
2267 | ||
2268 | ret = elv_register(&iosched_cfq); | |
22e2c507 JA |
2269 | if (ret) |
2270 | cfq_slab_kill(); | |
1da177e4 | 2271 | |
1da177e4 LT |
2272 | return ret; |
2273 | } | |
2274 | ||
2275 | static void __exit cfq_exit(void) | |
2276 | { | |
334e94de | 2277 | DECLARE_COMPLETION(all_gone); |
1da177e4 | 2278 | elv_unregister(&iosched_cfq); |
334e94de | 2279 | ioc_gone = &all_gone; |
fba82272 OH |
2280 | /* ioc_gone's update must be visible before reading ioc_count */ |
2281 | smp_wmb(); | |
334e94de | 2282 | if (atomic_read(&ioc_count)) |
fba82272 | 2283 | wait_for_completion(ioc_gone); |
334e94de | 2284 | synchronize_rcu(); |
83521d3e | 2285 | cfq_slab_kill(); |
1da177e4 LT |
2286 | } |
2287 | ||
2288 | module_init(cfq_init); | |
2289 | module_exit(cfq_exit); | |
2290 | ||
2291 | MODULE_AUTHOR("Jens Axboe"); | |
2292 | MODULE_LICENSE("GPL"); | |
2293 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |