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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 | 19 | static const int cfq_quantum = 4; /* max queue in one round of service */ |
64100099 AV |
20 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
21 | static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ | |
22 | static const int cfq_back_penalty = 2; /* penalty of a backwards seek */ | |
1da177e4 | 23 | |
64100099 | 24 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 25 | static int cfq_slice_async = HZ / 25; |
64100099 | 26 | static const int cfq_slice_async_rq = 2; |
caaa5f9f | 27 | static int cfq_slice_idle = HZ / 125; |
22e2c507 JA |
28 | |
29 | #define CFQ_IDLE_GRACE (HZ / 10) | |
30 | #define CFQ_SLICE_SCALE (5) | |
31 | ||
32 | #define CFQ_KEY_ASYNC (0) | |
22e2c507 | 33 | |
1da177e4 LT |
34 | /* |
35 | * for the hash of cfqq inside the cfqd | |
36 | */ | |
37 | #define CFQ_QHASH_SHIFT 6 | |
38 | #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) | |
39 | #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) | |
40 | ||
1da177e4 LT |
41 | #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) |
42 | ||
5e705374 JA |
43 | #define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private) |
44 | #define RQ_CFQQ(rq) ((rq)->elevator_private2) | |
1da177e4 | 45 | |
1da177e4 LT |
46 | static kmem_cache_t *cfq_pool; |
47 | static kmem_cache_t *cfq_ioc_pool; | |
48 | ||
4050cf16 | 49 | static DEFINE_PER_CPU(unsigned long, ioc_count); |
334e94de AV |
50 | static struct completion *ioc_gone; |
51 | ||
22e2c507 JA |
52 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
53 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
22e2c507 JA |
54 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) |
55 | ||
3b18152c JA |
56 | #define ASYNC (0) |
57 | #define SYNC (1) | |
58 | ||
59 | #define cfq_cfqq_dispatched(cfqq) \ | |
60 | ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) | |
61 | ||
62 | #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) | |
63 | ||
64 | #define cfq_cfqq_sync(cfqq) \ | |
65 | (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) | |
22e2c507 | 66 | |
206dc69b JA |
67 | #define sample_valid(samples) ((samples) > 80) |
68 | ||
22e2c507 JA |
69 | /* |
70 | * Per block device queue structure | |
71 | */ | |
1da177e4 | 72 | struct cfq_data { |
22e2c507 JA |
73 | request_queue_t *queue; |
74 | ||
75 | /* | |
76 | * rr list of queues with requests and the count of them | |
77 | */ | |
78 | struct list_head rr_list[CFQ_PRIO_LISTS]; | |
79 | struct list_head busy_rr; | |
80 | struct list_head cur_rr; | |
81 | struct list_head idle_rr; | |
82 | unsigned int busy_queues; | |
83 | ||
84 | /* | |
85 | * non-ordered list of empty cfqq's | |
86 | */ | |
1da177e4 LT |
87 | struct list_head empty_list; |
88 | ||
22e2c507 JA |
89 | /* |
90 | * cfqq lookup hash | |
91 | */ | |
1da177e4 | 92 | struct hlist_head *cfq_hash; |
1da177e4 | 93 | |
22e2c507 | 94 | int rq_in_driver; |
25776e35 | 95 | int hw_tag; |
1da177e4 | 96 | |
22e2c507 JA |
97 | /* |
98 | * idle window management | |
99 | */ | |
100 | struct timer_list idle_slice_timer; | |
101 | struct work_struct unplug_work; | |
1da177e4 | 102 | |
22e2c507 JA |
103 | struct cfq_queue *active_queue; |
104 | struct cfq_io_context *active_cic; | |
105 | int cur_prio, cur_end_prio; | |
106 | unsigned int dispatch_slice; | |
107 | ||
108 | struct timer_list idle_class_timer; | |
1da177e4 LT |
109 | |
110 | sector_t last_sector; | |
22e2c507 | 111 | unsigned long last_end_request; |
1da177e4 | 112 | |
1da177e4 LT |
113 | /* |
114 | * tunables, see top of file | |
115 | */ | |
116 | unsigned int cfq_quantum; | |
22e2c507 | 117 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
118 | unsigned int cfq_back_penalty; |
119 | unsigned int cfq_back_max; | |
22e2c507 JA |
120 | unsigned int cfq_slice[2]; |
121 | unsigned int cfq_slice_async_rq; | |
122 | unsigned int cfq_slice_idle; | |
d9ff4187 AV |
123 | |
124 | struct list_head cic_list; | |
1da177e4 LT |
125 | }; |
126 | ||
22e2c507 JA |
127 | /* |
128 | * Per process-grouping structure | |
129 | */ | |
1da177e4 LT |
130 | struct cfq_queue { |
131 | /* reference count */ | |
132 | atomic_t ref; | |
133 | /* parent cfq_data */ | |
134 | struct cfq_data *cfqd; | |
22e2c507 | 135 | /* cfqq lookup hash */ |
1da177e4 LT |
136 | struct hlist_node cfq_hash; |
137 | /* hash key */ | |
22e2c507 | 138 | unsigned int key; |
1da177e4 LT |
139 | /* on either rr or empty list of cfqd */ |
140 | struct list_head cfq_list; | |
141 | /* sorted list of pending requests */ | |
142 | struct rb_root sort_list; | |
143 | /* if fifo isn't expired, next request to serve */ | |
5e705374 | 144 | struct request *next_rq; |
1da177e4 LT |
145 | /* requests queued in sort_list */ |
146 | int queued[2]; | |
147 | /* currently allocated requests */ | |
148 | int allocated[2]; | |
149 | /* fifo list of requests in sort_list */ | |
22e2c507 | 150 | struct list_head fifo; |
1da177e4 | 151 | |
22e2c507 JA |
152 | unsigned long slice_start; |
153 | unsigned long slice_end; | |
154 | unsigned long slice_left; | |
155 | unsigned long service_last; | |
1da177e4 | 156 | |
3b18152c JA |
157 | /* number of requests that are on the dispatch list */ |
158 | int on_dispatch[2]; | |
22e2c507 JA |
159 | |
160 | /* io prio of this group */ | |
161 | unsigned short ioprio, org_ioprio; | |
162 | unsigned short ioprio_class, org_ioprio_class; | |
163 | ||
3b18152c JA |
164 | /* various state flags, see below */ |
165 | unsigned int flags; | |
1da177e4 LT |
166 | }; |
167 | ||
3b18152c JA |
168 | enum cfqq_state_flags { |
169 | CFQ_CFQQ_FLAG_on_rr = 0, | |
170 | CFQ_CFQQ_FLAG_wait_request, | |
171 | CFQ_CFQQ_FLAG_must_alloc, | |
172 | CFQ_CFQQ_FLAG_must_alloc_slice, | |
173 | CFQ_CFQQ_FLAG_must_dispatch, | |
174 | CFQ_CFQQ_FLAG_fifo_expire, | |
175 | CFQ_CFQQ_FLAG_idle_window, | |
176 | CFQ_CFQQ_FLAG_prio_changed, | |
3b18152c JA |
177 | }; |
178 | ||
179 | #define CFQ_CFQQ_FNS(name) \ | |
180 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
181 | { \ | |
182 | cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ | |
183 | } \ | |
184 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
185 | { \ | |
186 | cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ | |
187 | } \ | |
188 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
189 | { \ | |
190 | return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ | |
191 | } | |
192 | ||
193 | CFQ_CFQQ_FNS(on_rr); | |
194 | CFQ_CFQQ_FNS(wait_request); | |
195 | CFQ_CFQQ_FNS(must_alloc); | |
196 | CFQ_CFQQ_FNS(must_alloc_slice); | |
197 | CFQ_CFQQ_FNS(must_dispatch); | |
198 | CFQ_CFQQ_FNS(fifo_expire); | |
199 | CFQ_CFQQ_FNS(idle_window); | |
200 | CFQ_CFQQ_FNS(prio_changed); | |
3b18152c JA |
201 | #undef CFQ_CFQQ_FNS |
202 | ||
3b18152c | 203 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); |
5e705374 | 204 | static void cfq_dispatch_insert(request_queue_t *, struct request *); |
6f325a13 | 205 | static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); |
1da177e4 | 206 | |
99f95e52 AM |
207 | /* |
208 | * scheduler run of queue, if there are requests pending and no one in the | |
209 | * driver that will restart queueing | |
210 | */ | |
211 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) | |
212 | { | |
7b14e3b5 | 213 | if (cfqd->busy_queues) |
99f95e52 AM |
214 | kblockd_schedule_work(&cfqd->unplug_work); |
215 | } | |
216 | ||
217 | static int cfq_queue_empty(request_queue_t *q) | |
218 | { | |
219 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
220 | ||
b4878f24 | 221 | return !cfqd->busy_queues; |
99f95e52 AM |
222 | } |
223 | ||
206dc69b JA |
224 | static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
225 | { | |
b31dc66a | 226 | if (rw == READ || rw == WRITE_SYNC) |
206dc69b JA |
227 | return task->pid; |
228 | ||
229 | return CFQ_KEY_ASYNC; | |
230 | } | |
231 | ||
1da177e4 | 232 | /* |
5e705374 | 233 | * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
1da177e4 | 234 | * We choose the request that is closest to the head right now. Distance |
e8a99053 | 235 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 | 236 | */ |
5e705374 JA |
237 | static struct request * |
238 | cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2) | |
1da177e4 LT |
239 | { |
240 | sector_t last, s1, s2, d1 = 0, d2 = 0; | |
1da177e4 | 241 | unsigned long back_max; |
e8a99053 AM |
242 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
243 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
244 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 | 245 | |
5e705374 JA |
246 | if (rq1 == NULL || rq1 == rq2) |
247 | return rq2; | |
248 | if (rq2 == NULL) | |
249 | return rq1; | |
9c2c38a1 | 250 | |
5e705374 JA |
251 | if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
252 | return rq1; | |
253 | else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) | |
254 | return rq2; | |
1da177e4 | 255 | |
5e705374 JA |
256 | s1 = rq1->sector; |
257 | s2 = rq2->sector; | |
1da177e4 LT |
258 | |
259 | last = cfqd->last_sector; | |
260 | ||
1da177e4 LT |
261 | /* |
262 | * by definition, 1KiB is 2 sectors | |
263 | */ | |
264 | back_max = cfqd->cfq_back_max * 2; | |
265 | ||
266 | /* | |
267 | * Strict one way elevator _except_ in the case where we allow | |
268 | * short backward seeks which are biased as twice the cost of a | |
269 | * similar forward seek. | |
270 | */ | |
271 | if (s1 >= last) | |
272 | d1 = s1 - last; | |
273 | else if (s1 + back_max >= last) | |
274 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
275 | else | |
e8a99053 | 276 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
277 | |
278 | if (s2 >= last) | |
279 | d2 = s2 - last; | |
280 | else if (s2 + back_max >= last) | |
281 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
282 | else | |
e8a99053 | 283 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
284 | |
285 | /* Found required data */ | |
e8a99053 AM |
286 | |
287 | /* | |
288 | * By doing switch() on the bit mask "wrap" we avoid having to | |
289 | * check two variables for all permutations: --> faster! | |
290 | */ | |
291 | switch (wrap) { | |
5e705374 | 292 | case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
e8a99053 | 293 | if (d1 < d2) |
5e705374 | 294 | return rq1; |
e8a99053 | 295 | else if (d2 < d1) |
5e705374 | 296 | return rq2; |
e8a99053 AM |
297 | else { |
298 | if (s1 >= s2) | |
5e705374 | 299 | return rq1; |
e8a99053 | 300 | else |
5e705374 | 301 | return rq2; |
e8a99053 | 302 | } |
1da177e4 | 303 | |
e8a99053 | 304 | case CFQ_RQ2_WRAP: |
5e705374 | 305 | return rq1; |
e8a99053 | 306 | case CFQ_RQ1_WRAP: |
5e705374 JA |
307 | return rq2; |
308 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ | |
e8a99053 AM |
309 | default: |
310 | /* | |
311 | * Since both rqs are wrapped, | |
312 | * start with the one that's further behind head | |
313 | * (--> only *one* back seek required), | |
314 | * since back seek takes more time than forward. | |
315 | */ | |
316 | if (s1 <= s2) | |
5e705374 | 317 | return rq1; |
1da177e4 | 318 | else |
5e705374 | 319 | return rq2; |
1da177e4 LT |
320 | } |
321 | } | |
322 | ||
323 | /* | |
324 | * would be nice to take fifo expire time into account as well | |
325 | */ | |
5e705374 JA |
326 | static struct request * |
327 | cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
328 | struct request *last) | |
1da177e4 | 329 | { |
21183b07 JA |
330 | struct rb_node *rbnext = rb_next(&last->rb_node); |
331 | struct rb_node *rbprev = rb_prev(&last->rb_node); | |
5e705374 | 332 | struct request *next = NULL, *prev = NULL; |
1da177e4 | 333 | |
21183b07 | 334 | BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
1da177e4 LT |
335 | |
336 | if (rbprev) | |
5e705374 | 337 | prev = rb_entry_rq(rbprev); |
1da177e4 | 338 | |
21183b07 | 339 | if (rbnext) |
5e705374 | 340 | next = rb_entry_rq(rbnext); |
21183b07 JA |
341 | else { |
342 | rbnext = rb_first(&cfqq->sort_list); | |
343 | if (rbnext && rbnext != &last->rb_node) | |
5e705374 | 344 | next = rb_entry_rq(rbnext); |
21183b07 | 345 | } |
1da177e4 | 346 | |
21183b07 | 347 | return cfq_choose_req(cfqd, next, prev); |
1da177e4 LT |
348 | } |
349 | ||
22e2c507 | 350 | static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
1da177e4 | 351 | { |
22e2c507 JA |
352 | struct cfq_data *cfqd = cfqq->cfqd; |
353 | struct list_head *list, *entry; | |
1da177e4 | 354 | |
3b18152c | 355 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 356 | |
22e2c507 | 357 | list_del(&cfqq->cfq_list); |
1da177e4 | 358 | |
22e2c507 JA |
359 | if (cfq_class_rt(cfqq)) |
360 | list = &cfqd->cur_rr; | |
361 | else if (cfq_class_idle(cfqq)) | |
362 | list = &cfqd->idle_rr; | |
363 | else { | |
364 | /* | |
365 | * if cfqq has requests in flight, don't allow it to be | |
366 | * found in cfq_set_active_queue before it has finished them. | |
367 | * this is done to increase fairness between a process that | |
368 | * has lots of io pending vs one that only generates one | |
369 | * sporadically or synchronously | |
370 | */ | |
3b18152c | 371 | if (cfq_cfqq_dispatched(cfqq)) |
22e2c507 JA |
372 | list = &cfqd->busy_rr; |
373 | else | |
374 | list = &cfqd->rr_list[cfqq->ioprio]; | |
1da177e4 LT |
375 | } |
376 | ||
22e2c507 JA |
377 | /* |
378 | * if queue was preempted, just add to front to be fair. busy_rr | |
b52a8348 | 379 | * isn't sorted, but insert at the back for fairness. |
22e2c507 JA |
380 | */ |
381 | if (preempted || list == &cfqd->busy_rr) { | |
b52a8348 JA |
382 | if (preempted) |
383 | list = list->prev; | |
384 | ||
385 | list_add_tail(&cfqq->cfq_list, list); | |
1da177e4 | 386 | return; |
22e2c507 | 387 | } |
1da177e4 LT |
388 | |
389 | /* | |
22e2c507 | 390 | * sort by when queue was last serviced |
1da177e4 | 391 | */ |
22e2c507 JA |
392 | entry = list; |
393 | while ((entry = entry->prev) != list) { | |
1da177e4 LT |
394 | struct cfq_queue *__cfqq = list_entry_cfqq(entry); |
395 | ||
22e2c507 JA |
396 | if (!__cfqq->service_last) |
397 | break; | |
398 | if (time_before(__cfqq->service_last, cfqq->service_last)) | |
1da177e4 | 399 | break; |
1da177e4 LT |
400 | } |
401 | ||
402 | list_add(&cfqq->cfq_list, entry); | |
403 | } | |
404 | ||
405 | /* | |
406 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 407 | * the pending list according to last request service |
1da177e4 LT |
408 | */ |
409 | static inline void | |
b4878f24 | 410 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 411 | { |
3b18152c JA |
412 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
413 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
414 | cfqd->busy_queues++; |
415 | ||
b4878f24 | 416 | cfq_resort_rr_list(cfqq, 0); |
1da177e4 LT |
417 | } |
418 | ||
419 | static inline void | |
420 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
421 | { | |
3b18152c JA |
422 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
423 | cfq_clear_cfqq_on_rr(cfqq); | |
22e2c507 | 424 | list_move(&cfqq->cfq_list, &cfqd->empty_list); |
1da177e4 LT |
425 | |
426 | BUG_ON(!cfqd->busy_queues); | |
427 | cfqd->busy_queues--; | |
428 | } | |
429 | ||
430 | /* | |
431 | * rb tree support functions | |
432 | */ | |
5e705374 | 433 | static inline void cfq_del_rq_rb(struct request *rq) |
1da177e4 | 434 | { |
5e705374 | 435 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 436 | struct cfq_data *cfqd = cfqq->cfqd; |
5e705374 | 437 | const int sync = rq_is_sync(rq); |
1da177e4 | 438 | |
b4878f24 JA |
439 | BUG_ON(!cfqq->queued[sync]); |
440 | cfqq->queued[sync]--; | |
1da177e4 | 441 | |
5e705374 | 442 | elv_rb_del(&cfqq->sort_list, rq); |
1da177e4 | 443 | |
dd67d051 | 444 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
b4878f24 | 445 | cfq_del_cfqq_rr(cfqd, cfqq); |
1da177e4 LT |
446 | } |
447 | ||
5e705374 | 448 | static void cfq_add_rq_rb(struct request *rq) |
1da177e4 | 449 | { |
5e705374 | 450 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 451 | struct cfq_data *cfqd = cfqq->cfqd; |
21183b07 | 452 | struct request *__alias; |
1da177e4 | 453 | |
5380a101 | 454 | cfqq->queued[rq_is_sync(rq)]++; |
1da177e4 LT |
455 | |
456 | /* | |
457 | * looks a little odd, but the first insert might return an alias. | |
458 | * if that happens, put the alias on the dispatch list | |
459 | */ | |
21183b07 | 460 | while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
5e705374 | 461 | cfq_dispatch_insert(cfqd->queue, __alias); |
1da177e4 LT |
462 | } |
463 | ||
464 | static inline void | |
5e705374 | 465 | cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
1da177e4 | 466 | { |
5380a101 JA |
467 | elv_rb_del(&cfqq->sort_list, rq); |
468 | cfqq->queued[rq_is_sync(rq)]--; | |
5e705374 | 469 | cfq_add_rq_rb(rq); |
1da177e4 LT |
470 | } |
471 | ||
206dc69b JA |
472 | static struct request * |
473 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 474 | { |
206dc69b JA |
475 | struct task_struct *tsk = current; |
476 | pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio)); | |
477 | struct cfq_queue *cfqq; | |
1da177e4 | 478 | |
206dc69b | 479 | cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); |
89850f7e JA |
480 | if (cfqq) { |
481 | sector_t sector = bio->bi_sector + bio_sectors(bio); | |
482 | ||
21183b07 | 483 | return elv_rb_find(&cfqq->sort_list, sector); |
89850f7e | 484 | } |
1da177e4 | 485 | |
1da177e4 LT |
486 | return NULL; |
487 | } | |
488 | ||
b4878f24 | 489 | static void cfq_activate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 490 | { |
22e2c507 | 491 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 492 | |
b4878f24 | 493 | cfqd->rq_in_driver++; |
25776e35 JA |
494 | |
495 | /* | |
496 | * If the depth is larger 1, it really could be queueing. But lets | |
497 | * make the mark a little higher - idling could still be good for | |
498 | * low queueing, and a low queueing number could also just indicate | |
499 | * a SCSI mid layer like behaviour where limit+1 is often seen. | |
500 | */ | |
501 | if (!cfqd->hw_tag && cfqd->rq_in_driver > 4) | |
502 | cfqd->hw_tag = 1; | |
1da177e4 LT |
503 | } |
504 | ||
b4878f24 | 505 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 506 | { |
b4878f24 JA |
507 | struct cfq_data *cfqd = q->elevator->elevator_data; |
508 | ||
509 | WARN_ON(!cfqd->rq_in_driver); | |
510 | cfqd->rq_in_driver--; | |
1da177e4 LT |
511 | } |
512 | ||
b4878f24 | 513 | static void cfq_remove_request(struct request *rq) |
1da177e4 | 514 | { |
5e705374 | 515 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
21183b07 | 516 | |
5e705374 JA |
517 | if (cfqq->next_rq == rq) |
518 | cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); | |
1da177e4 | 519 | |
b4878f24 | 520 | list_del_init(&rq->queuelist); |
5e705374 | 521 | cfq_del_rq_rb(rq); |
1da177e4 LT |
522 | } |
523 | ||
524 | static int | |
525 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
526 | { | |
527 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
528 | struct request *__rq; | |
1da177e4 | 529 | |
206dc69b | 530 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 531 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
532 | *req = __rq; |
533 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
534 | } |
535 | ||
536 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
537 | } |
538 | ||
21183b07 JA |
539 | static void cfq_merged_request(request_queue_t *q, struct request *req, |
540 | int type) | |
1da177e4 | 541 | { |
21183b07 | 542 | if (type == ELEVATOR_FRONT_MERGE) { |
5e705374 | 543 | struct cfq_queue *cfqq = RQ_CFQQ(req); |
1da177e4 | 544 | |
5e705374 | 545 | cfq_reposition_rq_rb(cfqq, req); |
1da177e4 | 546 | } |
1da177e4 LT |
547 | } |
548 | ||
549 | static void | |
550 | cfq_merged_requests(request_queue_t *q, struct request *rq, | |
551 | struct request *next) | |
552 | { | |
22e2c507 JA |
553 | /* |
554 | * reposition in fifo if next is older than rq | |
555 | */ | |
556 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
557 | time_before(next->start_time, rq->start_time)) | |
558 | list_move(&rq->queuelist, &next->queuelist); | |
559 | ||
b4878f24 | 560 | cfq_remove_request(next); |
22e2c507 JA |
561 | } |
562 | ||
563 | static inline void | |
564 | __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
565 | { | |
566 | if (cfqq) { | |
567 | /* | |
568 | * stop potential idle class queues waiting service | |
569 | */ | |
570 | del_timer(&cfqd->idle_class_timer); | |
571 | ||
572 | cfqq->slice_start = jiffies; | |
573 | cfqq->slice_end = 0; | |
574 | cfqq->slice_left = 0; | |
3b18152c JA |
575 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
576 | cfq_clear_cfqq_fifo_expire(cfqq); | |
22e2c507 JA |
577 | } |
578 | ||
579 | cfqd->active_queue = cfqq; | |
580 | } | |
581 | ||
7b14e3b5 JA |
582 | /* |
583 | * current cfqq expired its slice (or was too idle), select new one | |
584 | */ | |
585 | static void | |
586 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
587 | int preempted) | |
588 | { | |
589 | unsigned long now = jiffies; | |
590 | ||
591 | if (cfq_cfqq_wait_request(cfqq)) | |
592 | del_timer(&cfqd->idle_slice_timer); | |
593 | ||
594 | if (!preempted && !cfq_cfqq_dispatched(cfqq)) { | |
595 | cfqq->service_last = now; | |
596 | cfq_schedule_dispatch(cfqd); | |
597 | } | |
598 | ||
599 | cfq_clear_cfqq_must_dispatch(cfqq); | |
600 | cfq_clear_cfqq_wait_request(cfqq); | |
601 | ||
602 | /* | |
603 | * store what was left of this slice, if the queue idled out | |
604 | * or was preempted | |
605 | */ | |
606 | if (time_after(cfqq->slice_end, now)) | |
607 | cfqq->slice_left = cfqq->slice_end - now; | |
608 | else | |
609 | cfqq->slice_left = 0; | |
610 | ||
611 | if (cfq_cfqq_on_rr(cfqq)) | |
612 | cfq_resort_rr_list(cfqq, preempted); | |
613 | ||
614 | if (cfqq == cfqd->active_queue) | |
615 | cfqd->active_queue = NULL; | |
616 | ||
617 | if (cfqd->active_cic) { | |
618 | put_io_context(cfqd->active_cic->ioc); | |
619 | cfqd->active_cic = NULL; | |
620 | } | |
621 | ||
622 | cfqd->dispatch_slice = 0; | |
623 | } | |
624 | ||
625 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) | |
626 | { | |
627 | struct cfq_queue *cfqq = cfqd->active_queue; | |
628 | ||
629 | if (cfqq) | |
630 | __cfq_slice_expired(cfqd, cfqq, preempted); | |
631 | } | |
632 | ||
22e2c507 JA |
633 | /* |
634 | * 0 | |
635 | * 0,1 | |
636 | * 0,1,2 | |
637 | * 0,1,2,3 | |
638 | * 0,1,2,3,4 | |
639 | * 0,1,2,3,4,5 | |
640 | * 0,1,2,3,4,5,6 | |
641 | * 0,1,2,3,4,5,6,7 | |
642 | */ | |
643 | static int cfq_get_next_prio_level(struct cfq_data *cfqd) | |
644 | { | |
645 | int prio, wrap; | |
646 | ||
647 | prio = -1; | |
648 | wrap = 0; | |
649 | do { | |
650 | int p; | |
651 | ||
652 | for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { | |
653 | if (!list_empty(&cfqd->rr_list[p])) { | |
654 | prio = p; | |
655 | break; | |
656 | } | |
657 | } | |
658 | ||
659 | if (prio != -1) | |
660 | break; | |
661 | cfqd->cur_prio = 0; | |
662 | if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
663 | cfqd->cur_end_prio = 0; | |
664 | if (wrap) | |
665 | break; | |
666 | wrap = 1; | |
1da177e4 | 667 | } |
22e2c507 JA |
668 | } while (1); |
669 | ||
670 | if (unlikely(prio == -1)) | |
671 | return -1; | |
672 | ||
673 | BUG_ON(prio >= CFQ_PRIO_LISTS); | |
674 | ||
675 | list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); | |
676 | ||
677 | cfqd->cur_prio = prio + 1; | |
678 | if (cfqd->cur_prio > cfqd->cur_end_prio) { | |
679 | cfqd->cur_end_prio = cfqd->cur_prio; | |
680 | cfqd->cur_prio = 0; | |
681 | } | |
682 | if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
683 | cfqd->cur_prio = 0; | |
684 | cfqd->cur_end_prio = 0; | |
1da177e4 LT |
685 | } |
686 | ||
22e2c507 JA |
687 | return prio; |
688 | } | |
689 | ||
3b18152c | 690 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
22e2c507 | 691 | { |
7b14e3b5 | 692 | struct cfq_queue *cfqq = NULL; |
22e2c507 | 693 | |
89850f7e JA |
694 | if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) { |
695 | /* | |
696 | * if current list is non-empty, grab first entry. if it is | |
697 | * empty, get next prio level and grab first entry then if any | |
698 | * are spliced | |
699 | */ | |
22e2c507 | 700 | cfqq = list_entry_cfqq(cfqd->cur_rr.next); |
89850f7e JA |
701 | } else if (!list_empty(&cfqd->busy_rr)) { |
702 | /* | |
703 | * If no new queues are available, check if the busy list has | |
704 | * some before falling back to idle io. | |
705 | */ | |
e0de0206 | 706 | cfqq = list_entry_cfqq(cfqd->busy_rr.next); |
89850f7e JA |
707 | } else if (!list_empty(&cfqd->idle_rr)) { |
708 | /* | |
709 | * if we have idle queues and no rt or be queues had pending | |
710 | * requests, either allow immediate service if the grace period | |
711 | * has passed or arm the idle grace timer | |
712 | */ | |
22e2c507 JA |
713 | unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; |
714 | ||
715 | if (time_after_eq(jiffies, end)) | |
716 | cfqq = list_entry_cfqq(cfqd->idle_rr.next); | |
717 | else | |
718 | mod_timer(&cfqd->idle_class_timer, end); | |
719 | } | |
720 | ||
721 | __cfq_set_active_queue(cfqd, cfqq); | |
3b18152c | 722 | return cfqq; |
22e2c507 JA |
723 | } |
724 | ||
caaa5f9f JA |
725 | #define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024)) |
726 | ||
22e2c507 JA |
727 | static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
728 | ||
729 | { | |
206dc69b | 730 | struct cfq_io_context *cic; |
7b14e3b5 JA |
731 | unsigned long sl; |
732 | ||
dd67d051 | 733 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
22e2c507 JA |
734 | WARN_ON(cfqq != cfqd->active_queue); |
735 | ||
736 | /* | |
737 | * idle is disabled, either manually or by past process history | |
738 | */ | |
739 | if (!cfqd->cfq_slice_idle) | |
740 | return 0; | |
3b18152c | 741 | if (!cfq_cfqq_idle_window(cfqq)) |
22e2c507 JA |
742 | return 0; |
743 | /* | |
744 | * task has exited, don't wait | |
745 | */ | |
206dc69b JA |
746 | cic = cfqd->active_cic; |
747 | if (!cic || !cic->ioc->task) | |
22e2c507 JA |
748 | return 0; |
749 | ||
3b18152c JA |
750 | cfq_mark_cfqq_must_dispatch(cfqq); |
751 | cfq_mark_cfqq_wait_request(cfqq); | |
22e2c507 | 752 | |
7b14e3b5 | 753 | sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
206dc69b JA |
754 | |
755 | /* | |
756 | * we don't want to idle for seeks, but we do want to allow | |
757 | * fair distribution of slice time for a process doing back-to-back | |
758 | * seeks. so allow a little bit of time for him to submit a new rq | |
759 | */ | |
caaa5f9f | 760 | if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic)) |
44eb1231 | 761 | sl = min(sl, msecs_to_jiffies(2)); |
206dc69b | 762 | |
7b14e3b5 | 763 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
22e2c507 | 764 | return 1; |
1da177e4 LT |
765 | } |
766 | ||
5e705374 | 767 | static void cfq_dispatch_insert(request_queue_t *q, struct request *rq) |
1da177e4 LT |
768 | { |
769 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
5e705374 | 770 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 | 771 | |
5380a101 JA |
772 | cfq_remove_request(rq); |
773 | cfqq->on_dispatch[rq_is_sync(rq)]++; | |
774 | elv_dispatch_sort(q, rq); | |
fd61af03 JA |
775 | |
776 | rq = list_entry(q->queue_head.prev, struct request, queuelist); | |
777 | cfqd->last_sector = rq->sector + rq->nr_sectors; | |
1da177e4 LT |
778 | } |
779 | ||
780 | /* | |
781 | * return expired entry, or NULL to just start from scratch in rbtree | |
782 | */ | |
5e705374 | 783 | static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
1da177e4 LT |
784 | { |
785 | struct cfq_data *cfqd = cfqq->cfqd; | |
22e2c507 | 786 | struct request *rq; |
89850f7e | 787 | int fifo; |
1da177e4 | 788 | |
3b18152c | 789 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 | 790 | return NULL; |
89850f7e JA |
791 | if (list_empty(&cfqq->fifo)) |
792 | return NULL; | |
1da177e4 | 793 | |
89850f7e JA |
794 | fifo = cfq_cfqq_class_sync(cfqq); |
795 | rq = rq_entry_fifo(cfqq->fifo.next); | |
1da177e4 | 796 | |
89850f7e JA |
797 | if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { |
798 | cfq_mark_cfqq_fifo_expire(cfqq); | |
799 | return rq; | |
1da177e4 LT |
800 | } |
801 | ||
802 | return NULL; | |
803 | } | |
804 | ||
805 | /* | |
3b18152c JA |
806 | * Scale schedule slice based on io priority. Use the sync time slice only |
807 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
808 | * io only, should not get full sync slice length. | |
1da177e4 | 809 | */ |
22e2c507 JA |
810 | static inline int |
811 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
812 | { | |
813 | const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; | |
814 | ||
815 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); | |
816 | ||
817 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); | |
818 | } | |
819 | ||
1da177e4 | 820 | static inline void |
22e2c507 | 821 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 822 | { |
22e2c507 JA |
823 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
824 | } | |
1da177e4 | 825 | |
22e2c507 JA |
826 | static inline int |
827 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
828 | { | |
829 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 830 | |
22e2c507 | 831 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 832 | |
22e2c507 | 833 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
834 | } |
835 | ||
22e2c507 JA |
836 | /* |
837 | * get next queue for service | |
838 | */ | |
1b5ed5e1 | 839 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 840 | { |
22e2c507 | 841 | unsigned long now = jiffies; |
1da177e4 | 842 | struct cfq_queue *cfqq; |
1da177e4 | 843 | |
22e2c507 JA |
844 | cfqq = cfqd->active_queue; |
845 | if (!cfqq) | |
846 | goto new_queue; | |
1da177e4 | 847 | |
22e2c507 JA |
848 | /* |
849 | * slice has expired | |
850 | */ | |
3b18152c JA |
851 | if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) |
852 | goto expire; | |
1da177e4 | 853 | |
22e2c507 JA |
854 | /* |
855 | * if queue has requests, dispatch one. if not, check if | |
856 | * enough slice is left to wait for one | |
857 | */ | |
dd67d051 | 858 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 859 | goto keep_queue; |
caaa5f9f JA |
860 | else if (cfq_cfqq_dispatched(cfqq)) { |
861 | cfqq = NULL; | |
862 | goto keep_queue; | |
863 | } else if (cfq_cfqq_class_sync(cfqq)) { | |
22e2c507 JA |
864 | if (cfq_arm_slice_timer(cfqd, cfqq)) |
865 | return NULL; | |
866 | } | |
867 | ||
3b18152c | 868 | expire: |
22e2c507 | 869 | cfq_slice_expired(cfqd, 0); |
3b18152c JA |
870 | new_queue: |
871 | cfqq = cfq_set_active_queue(cfqd); | |
22e2c507 | 872 | keep_queue: |
3b18152c | 873 | return cfqq; |
22e2c507 JA |
874 | } |
875 | ||
876 | static int | |
877 | __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
878 | int max_dispatch) | |
879 | { | |
880 | int dispatched = 0; | |
881 | ||
dd67d051 | 882 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); |
22e2c507 JA |
883 | |
884 | do { | |
5e705374 | 885 | struct request *rq; |
1da177e4 LT |
886 | |
887 | /* | |
22e2c507 | 888 | * follow expired path, else get first next available |
1da177e4 | 889 | */ |
5e705374 JA |
890 | if ((rq = cfq_check_fifo(cfqq)) == NULL) |
891 | rq = cfqq->next_rq; | |
22e2c507 JA |
892 | |
893 | /* | |
894 | * finally, insert request into driver dispatch list | |
895 | */ | |
5e705374 | 896 | cfq_dispatch_insert(cfqd->queue, rq); |
1da177e4 | 897 | |
22e2c507 JA |
898 | cfqd->dispatch_slice++; |
899 | dispatched++; | |
1da177e4 | 900 | |
22e2c507 | 901 | if (!cfqd->active_cic) { |
5e705374 JA |
902 | atomic_inc(&RQ_CIC(rq)->ioc->refcount); |
903 | cfqd->active_cic = RQ_CIC(rq); | |
22e2c507 | 904 | } |
1da177e4 | 905 | |
dd67d051 | 906 | if (RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 JA |
907 | break; |
908 | ||
909 | } while (dispatched < max_dispatch); | |
910 | ||
911 | /* | |
caaa5f9f | 912 | * if slice end isn't set yet, set it. |
22e2c507 JA |
913 | */ |
914 | if (!cfqq->slice_end) | |
915 | cfq_set_prio_slice(cfqd, cfqq); | |
916 | ||
917 | /* | |
918 | * expire an async queue immediately if it has used up its slice. idle | |
919 | * queue always expire after 1 dispatch round. | |
920 | */ | |
921 | if ((!cfq_cfqq_sync(cfqq) && | |
922 | cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
caaa5f9f JA |
923 | cfq_class_idle(cfqq) || |
924 | !cfq_cfqq_idle_window(cfqq)) | |
22e2c507 JA |
925 | cfq_slice_expired(cfqd, 0); |
926 | ||
927 | return dispatched; | |
928 | } | |
929 | ||
1b5ed5e1 TH |
930 | static int |
931 | cfq_forced_dispatch_cfqqs(struct list_head *list) | |
932 | { | |
1b5ed5e1 | 933 | struct cfq_queue *cfqq, *next; |
caaa5f9f | 934 | int dispatched; |
1b5ed5e1 | 935 | |
caaa5f9f | 936 | dispatched = 0; |
1b5ed5e1 | 937 | list_for_each_entry_safe(cfqq, next, list, cfq_list) { |
5e705374 JA |
938 | while (cfqq->next_rq) { |
939 | cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); | |
1b5ed5e1 TH |
940 | dispatched++; |
941 | } | |
942 | BUG_ON(!list_empty(&cfqq->fifo)); | |
943 | } | |
caaa5f9f | 944 | |
1b5ed5e1 TH |
945 | return dispatched; |
946 | } | |
947 | ||
948 | static int | |
949 | cfq_forced_dispatch(struct cfq_data *cfqd) | |
950 | { | |
951 | int i, dispatched = 0; | |
952 | ||
953 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
954 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]); | |
955 | ||
956 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr); | |
957 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr); | |
958 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr); | |
959 | ||
960 | cfq_slice_expired(cfqd, 0); | |
961 | ||
962 | BUG_ON(cfqd->busy_queues); | |
963 | ||
964 | return dispatched; | |
965 | } | |
966 | ||
22e2c507 | 967 | static int |
b4878f24 | 968 | cfq_dispatch_requests(request_queue_t *q, int force) |
22e2c507 JA |
969 | { |
970 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
caaa5f9f JA |
971 | struct cfq_queue *cfqq, *prev_cfqq; |
972 | int dispatched; | |
22e2c507 JA |
973 | |
974 | if (!cfqd->busy_queues) | |
975 | return 0; | |
976 | ||
1b5ed5e1 TH |
977 | if (unlikely(force)) |
978 | return cfq_forced_dispatch(cfqd); | |
979 | ||
caaa5f9f JA |
980 | dispatched = 0; |
981 | prev_cfqq = NULL; | |
982 | while ((cfqq = cfq_select_queue(cfqd)) != NULL) { | |
b4878f24 JA |
983 | int max_dispatch; |
984 | ||
caaa5f9f JA |
985 | /* |
986 | * Don't repeat dispatch from the previous queue. | |
987 | */ | |
988 | if (prev_cfqq == cfqq) | |
989 | break; | |
990 | ||
3b18152c JA |
991 | cfq_clear_cfqq_must_dispatch(cfqq); |
992 | cfq_clear_cfqq_wait_request(cfqq); | |
22e2c507 JA |
993 | del_timer(&cfqd->idle_slice_timer); |
994 | ||
1b5ed5e1 TH |
995 | max_dispatch = cfqd->cfq_quantum; |
996 | if (cfq_class_idle(cfqq)) | |
997 | max_dispatch = 1; | |
1da177e4 | 998 | |
caaa5f9f JA |
999 | dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
1000 | ||
1001 | /* | |
1002 | * If the dispatch cfqq has idling enabled and is still | |
1003 | * the active queue, break out. | |
1004 | */ | |
1005 | if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue) | |
1006 | break; | |
1007 | ||
1008 | prev_cfqq = cfqq; | |
1da177e4 LT |
1009 | } |
1010 | ||
caaa5f9f | 1011 | return dispatched; |
1da177e4 LT |
1012 | } |
1013 | ||
1da177e4 | 1014 | /* |
5e705374 JA |
1015 | * task holds one reference to the queue, dropped when task exits. each rq |
1016 | * in-flight on this queue also holds a reference, dropped when rq is freed. | |
1da177e4 LT |
1017 | * |
1018 | * queue lock must be held here. | |
1019 | */ | |
1020 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
1021 | { | |
22e2c507 JA |
1022 | struct cfq_data *cfqd = cfqq->cfqd; |
1023 | ||
1024 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
1025 | |
1026 | if (!atomic_dec_and_test(&cfqq->ref)) | |
1027 | return; | |
1028 | ||
1029 | BUG_ON(rb_first(&cfqq->sort_list)); | |
22e2c507 | 1030 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3b18152c | 1031 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 1032 | |
7b14e3b5 | 1033 | if (unlikely(cfqd->active_queue == cfqq)) |
3b18152c | 1034 | __cfq_slice_expired(cfqd, cfqq, 0); |
22e2c507 | 1035 | |
1da177e4 LT |
1036 | /* |
1037 | * it's on the empty list and still hashed | |
1038 | */ | |
1039 | list_del(&cfqq->cfq_list); | |
1040 | hlist_del(&cfqq->cfq_hash); | |
1041 | kmem_cache_free(cfq_pool, cfqq); | |
1042 | } | |
1043 | ||
1ea25ecb | 1044 | static struct cfq_queue * |
3b18152c JA |
1045 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, |
1046 | const int hashval) | |
1da177e4 LT |
1047 | { |
1048 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; | |
206dc69b JA |
1049 | struct hlist_node *entry; |
1050 | struct cfq_queue *__cfqq; | |
1da177e4 | 1051 | |
206dc69b | 1052 | hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) { |
b0a6916b | 1053 | const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio); |
1da177e4 | 1054 | |
206dc69b | 1055 | if (__cfqq->key == key && (__p == prio || !prio)) |
1da177e4 LT |
1056 | return __cfqq; |
1057 | } | |
1058 | ||
1059 | return NULL; | |
1060 | } | |
1061 | ||
1062 | static struct cfq_queue * | |
3b18152c | 1063 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) |
1da177e4 | 1064 | { |
3b18152c | 1065 | return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); |
1da177e4 LT |
1066 | } |
1067 | ||
e2d74ac0 | 1068 | static void cfq_free_io_context(struct io_context *ioc) |
1da177e4 | 1069 | { |
22e2c507 | 1070 | struct cfq_io_context *__cic; |
e2d74ac0 JA |
1071 | struct rb_node *n; |
1072 | int freed = 0; | |
1da177e4 | 1073 | |
e2d74ac0 JA |
1074 | while ((n = rb_first(&ioc->cic_root)) != NULL) { |
1075 | __cic = rb_entry(n, struct cfq_io_context, rb_node); | |
1076 | rb_erase(&__cic->rb_node, &ioc->cic_root); | |
22e2c507 | 1077 | kmem_cache_free(cfq_ioc_pool, __cic); |
334e94de | 1078 | freed++; |
1da177e4 LT |
1079 | } |
1080 | ||
4050cf16 JA |
1081 | elv_ioc_count_mod(ioc_count, -freed); |
1082 | ||
1083 | if (ioc_gone && !elv_ioc_count_read(ioc_count)) | |
334e94de | 1084 | complete(ioc_gone); |
1da177e4 LT |
1085 | } |
1086 | ||
89850f7e | 1087 | static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1088 | { |
89850f7e JA |
1089 | if (unlikely(cfqq == cfqd->active_queue)) |
1090 | __cfq_slice_expired(cfqd, cfqq, 0); | |
22e2c507 | 1091 | |
89850f7e JA |
1092 | cfq_put_queue(cfqq); |
1093 | } | |
22e2c507 | 1094 | |
89850f7e JA |
1095 | static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
1096 | struct cfq_io_context *cic) | |
1097 | { | |
fc46379d JA |
1098 | list_del_init(&cic->queue_list); |
1099 | smp_wmb(); | |
1100 | cic->key = NULL; | |
1101 | ||
12a05732 | 1102 | if (cic->cfqq[ASYNC]) { |
89850f7e | 1103 | cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]); |
12a05732 AV |
1104 | cic->cfqq[ASYNC] = NULL; |
1105 | } | |
1106 | ||
1107 | if (cic->cfqq[SYNC]) { | |
89850f7e | 1108 | cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]); |
12a05732 AV |
1109 | cic->cfqq[SYNC] = NULL; |
1110 | } | |
89850f7e JA |
1111 | } |
1112 | ||
1113 | ||
1114 | /* | |
1115 | * Called with interrupts disabled | |
1116 | */ | |
1117 | static void cfq_exit_single_io_context(struct cfq_io_context *cic) | |
1118 | { | |
1119 | struct cfq_data *cfqd = cic->key; | |
1120 | ||
89850f7e JA |
1121 | if (cfqd) { |
1122 | request_queue_t *q = cfqd->queue; | |
1123 | ||
fc46379d | 1124 | spin_lock_irq(q->queue_lock); |
89850f7e | 1125 | __cfq_exit_single_io_context(cfqd, cic); |
fc46379d | 1126 | spin_unlock_irq(q->queue_lock); |
89850f7e | 1127 | } |
1da177e4 LT |
1128 | } |
1129 | ||
e2d74ac0 | 1130 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 1131 | { |
22e2c507 | 1132 | struct cfq_io_context *__cic; |
e2d74ac0 | 1133 | struct rb_node *n; |
22e2c507 | 1134 | |
1da177e4 LT |
1135 | /* |
1136 | * put the reference this task is holding to the various queues | |
1137 | */ | |
e2d74ac0 JA |
1138 | |
1139 | n = rb_first(&ioc->cic_root); | |
1140 | while (n != NULL) { | |
1141 | __cic = rb_entry(n, struct cfq_io_context, rb_node); | |
1142 | ||
22e2c507 | 1143 | cfq_exit_single_io_context(__cic); |
e2d74ac0 | 1144 | n = rb_next(n); |
1da177e4 | 1145 | } |
1da177e4 LT |
1146 | } |
1147 | ||
22e2c507 | 1148 | static struct cfq_io_context * |
8267e268 | 1149 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1150 | { |
b5deef90 | 1151 | struct cfq_io_context *cic; |
1da177e4 | 1152 | |
b5deef90 | 1153 | cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask, cfqd->queue->node); |
1da177e4 | 1154 | if (cic) { |
553698f9 | 1155 | memset(cic, 0, sizeof(*cic)); |
22e2c507 | 1156 | cic->last_end_request = jiffies; |
553698f9 | 1157 | INIT_LIST_HEAD(&cic->queue_list); |
22e2c507 JA |
1158 | cic->dtor = cfq_free_io_context; |
1159 | cic->exit = cfq_exit_io_context; | |
4050cf16 | 1160 | elv_ioc_count_inc(ioc_count); |
1da177e4 LT |
1161 | } |
1162 | ||
1163 | return cic; | |
1164 | } | |
1165 | ||
22e2c507 JA |
1166 | static void cfq_init_prio_data(struct cfq_queue *cfqq) |
1167 | { | |
1168 | struct task_struct *tsk = current; | |
1169 | int ioprio_class; | |
1170 | ||
3b18152c | 1171 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
1172 | return; |
1173 | ||
1174 | ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); | |
1175 | switch (ioprio_class) { | |
1176 | default: | |
1177 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
1178 | case IOPRIO_CLASS_NONE: | |
1179 | /* | |
1180 | * no prio set, place us in the middle of the BE classes | |
1181 | */ | |
1182 | cfqq->ioprio = task_nice_ioprio(tsk); | |
1183 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1184 | break; | |
1185 | case IOPRIO_CLASS_RT: | |
1186 | cfqq->ioprio = task_ioprio(tsk); | |
1187 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
1188 | break; | |
1189 | case IOPRIO_CLASS_BE: | |
1190 | cfqq->ioprio = task_ioprio(tsk); | |
1191 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1192 | break; | |
1193 | case IOPRIO_CLASS_IDLE: | |
1194 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
1195 | cfqq->ioprio = 7; | |
3b18152c | 1196 | cfq_clear_cfqq_idle_window(cfqq); |
22e2c507 JA |
1197 | break; |
1198 | } | |
1199 | ||
1200 | /* | |
1201 | * keep track of original prio settings in case we have to temporarily | |
1202 | * elevate the priority of this queue | |
1203 | */ | |
1204 | cfqq->org_ioprio = cfqq->ioprio; | |
1205 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
1206 | ||
3b18152c | 1207 | if (cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1208 | cfq_resort_rr_list(cfqq, 0); |
1209 | ||
3b18152c | 1210 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
1211 | } |
1212 | ||
478a82b0 | 1213 | static inline void changed_ioprio(struct cfq_io_context *cic) |
22e2c507 | 1214 | { |
478a82b0 AV |
1215 | struct cfq_data *cfqd = cic->key; |
1216 | struct cfq_queue *cfqq; | |
35e6077c | 1217 | |
caaa5f9f JA |
1218 | if (unlikely(!cfqd)) |
1219 | return; | |
1220 | ||
1221 | spin_lock(cfqd->queue->queue_lock); | |
1222 | ||
1223 | cfqq = cic->cfqq[ASYNC]; | |
1224 | if (cfqq) { | |
1225 | struct cfq_queue *new_cfqq; | |
1226 | new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task, | |
1227 | GFP_ATOMIC); | |
1228 | if (new_cfqq) { | |
1229 | cic->cfqq[ASYNC] = new_cfqq; | |
1230 | cfq_put_queue(cfqq); | |
1231 | } | |
22e2c507 | 1232 | } |
caaa5f9f JA |
1233 | |
1234 | cfqq = cic->cfqq[SYNC]; | |
1235 | if (cfqq) | |
1236 | cfq_mark_cfqq_prio_changed(cfqq); | |
1237 | ||
1238 | spin_unlock(cfqd->queue->queue_lock); | |
22e2c507 JA |
1239 | } |
1240 | ||
fc46379d | 1241 | static void cfq_ioc_set_ioprio(struct io_context *ioc) |
22e2c507 | 1242 | { |
a6a0763a | 1243 | struct cfq_io_context *cic; |
e2d74ac0 | 1244 | struct rb_node *n; |
a6a0763a | 1245 | |
fc46379d | 1246 | ioc->ioprio_changed = 0; |
a6a0763a | 1247 | |
e2d74ac0 JA |
1248 | n = rb_first(&ioc->cic_root); |
1249 | while (n != NULL) { | |
1250 | cic = rb_entry(n, struct cfq_io_context, rb_node); | |
3793c65c | 1251 | |
478a82b0 | 1252 | changed_ioprio(cic); |
e2d74ac0 JA |
1253 | n = rb_next(n); |
1254 | } | |
22e2c507 JA |
1255 | } |
1256 | ||
1257 | static struct cfq_queue * | |
6f325a13 | 1258 | cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, |
8267e268 | 1259 | gfp_t gfp_mask) |
22e2c507 JA |
1260 | { |
1261 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); | |
1262 | struct cfq_queue *cfqq, *new_cfqq = NULL; | |
6f325a13 | 1263 | unsigned short ioprio; |
22e2c507 JA |
1264 | |
1265 | retry: | |
6f325a13 | 1266 | ioprio = tsk->ioprio; |
3b18152c | 1267 | cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); |
22e2c507 JA |
1268 | |
1269 | if (!cfqq) { | |
1270 | if (new_cfqq) { | |
1271 | cfqq = new_cfqq; | |
1272 | new_cfqq = NULL; | |
1273 | } else if (gfp_mask & __GFP_WAIT) { | |
89850f7e JA |
1274 | /* |
1275 | * Inform the allocator of the fact that we will | |
1276 | * just repeat this allocation if it fails, to allow | |
1277 | * the allocator to do whatever it needs to attempt to | |
1278 | * free memory. | |
1279 | */ | |
22e2c507 | 1280 | spin_unlock_irq(cfqd->queue->queue_lock); |
b5deef90 | 1281 | new_cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask|__GFP_NOFAIL, cfqd->queue->node); |
22e2c507 JA |
1282 | spin_lock_irq(cfqd->queue->queue_lock); |
1283 | goto retry; | |
1284 | } else { | |
b5deef90 | 1285 | cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask, cfqd->queue->node); |
22e2c507 JA |
1286 | if (!cfqq) |
1287 | goto out; | |
1288 | } | |
1289 | ||
1290 | memset(cfqq, 0, sizeof(*cfqq)); | |
1291 | ||
1292 | INIT_HLIST_NODE(&cfqq->cfq_hash); | |
1293 | INIT_LIST_HEAD(&cfqq->cfq_list); | |
22e2c507 JA |
1294 | INIT_LIST_HEAD(&cfqq->fifo); |
1295 | ||
1296 | cfqq->key = key; | |
1297 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); | |
1298 | atomic_set(&cfqq->ref, 0); | |
1299 | cfqq->cfqd = cfqd; | |
22e2c507 JA |
1300 | cfqq->service_last = 0; |
1301 | /* | |
1302 | * set ->slice_left to allow preemption for a new process | |
1303 | */ | |
1304 | cfqq->slice_left = 2 * cfqd->cfq_slice_idle; | |
caaa5f9f | 1305 | cfq_mark_cfqq_idle_window(cfqq); |
3b18152c JA |
1306 | cfq_mark_cfqq_prio_changed(cfqq); |
1307 | cfq_init_prio_data(cfqq); | |
22e2c507 JA |
1308 | } |
1309 | ||
1310 | if (new_cfqq) | |
1311 | kmem_cache_free(cfq_pool, new_cfqq); | |
1312 | ||
1313 | atomic_inc(&cfqq->ref); | |
1314 | out: | |
1315 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); | |
1316 | return cfqq; | |
1317 | } | |
1318 | ||
dbecf3ab OH |
1319 | static void |
1320 | cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic) | |
1321 | { | |
fc46379d | 1322 | WARN_ON(!list_empty(&cic->queue_list)); |
dbecf3ab | 1323 | rb_erase(&cic->rb_node, &ioc->cic_root); |
dbecf3ab | 1324 | kmem_cache_free(cfq_ioc_pool, cic); |
4050cf16 | 1325 | elv_ioc_count_dec(ioc_count); |
dbecf3ab OH |
1326 | } |
1327 | ||
e2d74ac0 JA |
1328 | static struct cfq_io_context * |
1329 | cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc) | |
1330 | { | |
dbecf3ab | 1331 | struct rb_node *n; |
e2d74ac0 | 1332 | struct cfq_io_context *cic; |
be3b0753 | 1333 | void *k, *key = cfqd; |
e2d74ac0 | 1334 | |
dbecf3ab OH |
1335 | restart: |
1336 | n = ioc->cic_root.rb_node; | |
e2d74ac0 JA |
1337 | while (n) { |
1338 | cic = rb_entry(n, struct cfq_io_context, rb_node); | |
be3b0753 OH |
1339 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
1340 | k = cic->key; | |
1341 | if (unlikely(!k)) { | |
dbecf3ab OH |
1342 | cfq_drop_dead_cic(ioc, cic); |
1343 | goto restart; | |
1344 | } | |
e2d74ac0 | 1345 | |
be3b0753 | 1346 | if (key < k) |
e2d74ac0 | 1347 | n = n->rb_left; |
be3b0753 | 1348 | else if (key > k) |
e2d74ac0 JA |
1349 | n = n->rb_right; |
1350 | else | |
1351 | return cic; | |
1352 | } | |
1353 | ||
1354 | return NULL; | |
1355 | } | |
1356 | ||
1357 | static inline void | |
1358 | cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, | |
1359 | struct cfq_io_context *cic) | |
1360 | { | |
dbecf3ab OH |
1361 | struct rb_node **p; |
1362 | struct rb_node *parent; | |
e2d74ac0 | 1363 | struct cfq_io_context *__cic; |
be3b0753 | 1364 | void *k; |
e2d74ac0 | 1365 | |
e2d74ac0 JA |
1366 | cic->ioc = ioc; |
1367 | cic->key = cfqd; | |
1368 | ||
dbecf3ab OH |
1369 | restart: |
1370 | parent = NULL; | |
1371 | p = &ioc->cic_root.rb_node; | |
e2d74ac0 JA |
1372 | while (*p) { |
1373 | parent = *p; | |
1374 | __cic = rb_entry(parent, struct cfq_io_context, rb_node); | |
be3b0753 OH |
1375 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
1376 | k = __cic->key; | |
1377 | if (unlikely(!k)) { | |
be33c3a6 | 1378 | cfq_drop_dead_cic(ioc, __cic); |
dbecf3ab OH |
1379 | goto restart; |
1380 | } | |
e2d74ac0 | 1381 | |
be3b0753 | 1382 | if (cic->key < k) |
e2d74ac0 | 1383 | p = &(*p)->rb_left; |
be3b0753 | 1384 | else if (cic->key > k) |
e2d74ac0 JA |
1385 | p = &(*p)->rb_right; |
1386 | else | |
1387 | BUG(); | |
1388 | } | |
1389 | ||
1390 | rb_link_node(&cic->rb_node, parent, p); | |
1391 | rb_insert_color(&cic->rb_node, &ioc->cic_root); | |
fc46379d JA |
1392 | |
1393 | spin_lock_irq(cfqd->queue->queue_lock); | |
e2d74ac0 | 1394 | list_add(&cic->queue_list, &cfqd->cic_list); |
fc46379d | 1395 | spin_unlock_irq(cfqd->queue->queue_lock); |
e2d74ac0 JA |
1396 | } |
1397 | ||
1da177e4 LT |
1398 | /* |
1399 | * Setup general io context and cfq io context. There can be several cfq | |
1400 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 1401 | * than one device managed by cfq. |
1da177e4 LT |
1402 | */ |
1403 | static struct cfq_io_context * | |
e2d74ac0 | 1404 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1405 | { |
22e2c507 | 1406 | struct io_context *ioc = NULL; |
1da177e4 | 1407 | struct cfq_io_context *cic; |
1da177e4 | 1408 | |
22e2c507 | 1409 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 1410 | |
b5deef90 | 1411 | ioc = get_io_context(gfp_mask, cfqd->queue->node); |
1da177e4 LT |
1412 | if (!ioc) |
1413 | return NULL; | |
1414 | ||
e2d74ac0 JA |
1415 | cic = cfq_cic_rb_lookup(cfqd, ioc); |
1416 | if (cic) | |
1417 | goto out; | |
1da177e4 | 1418 | |
e2d74ac0 JA |
1419 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1420 | if (cic == NULL) | |
1421 | goto err; | |
1da177e4 | 1422 | |
e2d74ac0 | 1423 | cfq_cic_link(cfqd, ioc, cic); |
1da177e4 | 1424 | out: |
fc46379d JA |
1425 | smp_read_barrier_depends(); |
1426 | if (unlikely(ioc->ioprio_changed)) | |
1427 | cfq_ioc_set_ioprio(ioc); | |
1428 | ||
1da177e4 LT |
1429 | return cic; |
1430 | err: | |
1431 | put_io_context(ioc); | |
1432 | return NULL; | |
1433 | } | |
1434 | ||
22e2c507 JA |
1435 | static void |
1436 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 1437 | { |
22e2c507 | 1438 | unsigned long elapsed, ttime; |
1da177e4 | 1439 | |
22e2c507 JA |
1440 | /* |
1441 | * if this context already has stuff queued, thinktime is from | |
1442 | * last queue not last end | |
1443 | */ | |
1444 | #if 0 | |
1445 | if (time_after(cic->last_end_request, cic->last_queue)) | |
1446 | elapsed = jiffies - cic->last_end_request; | |
1447 | else | |
1448 | elapsed = jiffies - cic->last_queue; | |
1449 | #else | |
1450 | elapsed = jiffies - cic->last_end_request; | |
1451 | #endif | |
1da177e4 | 1452 | |
22e2c507 | 1453 | ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
db3b5848 | 1454 | |
22e2c507 JA |
1455 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
1456 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
1457 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
1458 | } | |
1da177e4 | 1459 | |
206dc69b JA |
1460 | static void |
1461 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
5e705374 | 1462 | struct request *rq) |
206dc69b JA |
1463 | { |
1464 | sector_t sdist; | |
1465 | u64 total; | |
1466 | ||
5e705374 JA |
1467 | if (cic->last_request_pos < rq->sector) |
1468 | sdist = rq->sector - cic->last_request_pos; | |
206dc69b | 1469 | else |
5e705374 | 1470 | sdist = cic->last_request_pos - rq->sector; |
206dc69b JA |
1471 | |
1472 | /* | |
1473 | * Don't allow the seek distance to get too large from the | |
1474 | * odd fragment, pagein, etc | |
1475 | */ | |
1476 | if (cic->seek_samples <= 60) /* second&third seek */ | |
1477 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024); | |
1478 | else | |
1479 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64); | |
1480 | ||
1481 | cic->seek_samples = (7*cic->seek_samples + 256) / 8; | |
1482 | cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8; | |
1483 | total = cic->seek_total + (cic->seek_samples/2); | |
1484 | do_div(total, cic->seek_samples); | |
1485 | cic->seek_mean = (sector_t)total; | |
1486 | } | |
1da177e4 | 1487 | |
22e2c507 JA |
1488 | /* |
1489 | * Disable idle window if the process thinks too long or seeks so much that | |
1490 | * it doesn't matter | |
1491 | */ | |
1492 | static void | |
1493 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1494 | struct cfq_io_context *cic) | |
1495 | { | |
3b18152c | 1496 | int enable_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 1497 | |
caaa5f9f JA |
1498 | if (!cic->ioc->task || !cfqd->cfq_slice_idle || |
1499 | (cfqd->hw_tag && CIC_SEEKY(cic))) | |
22e2c507 JA |
1500 | enable_idle = 0; |
1501 | else if (sample_valid(cic->ttime_samples)) { | |
1502 | if (cic->ttime_mean > cfqd->cfq_slice_idle) | |
1503 | enable_idle = 0; | |
1504 | else | |
1505 | enable_idle = 1; | |
1da177e4 LT |
1506 | } |
1507 | ||
3b18152c JA |
1508 | if (enable_idle) |
1509 | cfq_mark_cfqq_idle_window(cfqq); | |
1510 | else | |
1511 | cfq_clear_cfqq_idle_window(cfqq); | |
22e2c507 | 1512 | } |
1da177e4 | 1513 | |
22e2c507 JA |
1514 | |
1515 | /* | |
1516 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
1517 | * no or if we aren't sure, a 1 will cause a preempt. | |
1518 | */ | |
1519 | static int | |
1520 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, | |
5e705374 | 1521 | struct request *rq) |
22e2c507 JA |
1522 | { |
1523 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1524 | ||
1525 | if (cfq_class_idle(new_cfqq)) | |
1526 | return 0; | |
1527 | ||
1528 | if (!cfqq) | |
caaa5f9f | 1529 | return 0; |
22e2c507 JA |
1530 | |
1531 | if (cfq_class_idle(cfqq)) | |
1532 | return 1; | |
3b18152c | 1533 | if (!cfq_cfqq_wait_request(new_cfqq)) |
22e2c507 JA |
1534 | return 0; |
1535 | /* | |
1536 | * if it doesn't have slice left, forget it | |
1537 | */ | |
1538 | if (new_cfqq->slice_left < cfqd->cfq_slice_idle) | |
1539 | return 0; | |
5e705374 | 1540 | if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
22e2c507 JA |
1541 | return 1; |
1542 | ||
1543 | return 0; | |
1544 | } | |
1545 | ||
1546 | /* | |
1547 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
1548 | * let it have half of its nominal slice. | |
1549 | */ | |
1550 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1551 | { | |
1552 | struct cfq_queue *__cfqq, *next; | |
1553 | ||
1554 | list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) | |
1555 | cfq_resort_rr_list(__cfqq, 1); | |
1556 | ||
1557 | if (!cfqq->slice_left) | |
1558 | cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; | |
1559 | ||
1560 | cfqq->slice_end = cfqq->slice_left + jiffies; | |
caaa5f9f | 1561 | cfq_slice_expired(cfqd, 1); |
22e2c507 JA |
1562 | __cfq_set_active_queue(cfqd, cfqq); |
1563 | } | |
1564 | ||
1565 | /* | |
1566 | * should really be a ll_rw_blk.c helper | |
1567 | */ | |
1568 | static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1569 | { | |
1570 | request_queue_t *q = cfqd->queue; | |
1571 | ||
1572 | if (!blk_queue_plugged(q)) | |
1573 | q->request_fn(q); | |
1574 | else | |
1575 | __generic_unplug_device(q); | |
1576 | } | |
1577 | ||
1578 | /* | |
5e705374 | 1579 | * Called when a new fs request (rq) is added (to cfqq). Check if there's |
22e2c507 JA |
1580 | * something we should do about it |
1581 | */ | |
1582 | static void | |
5e705374 JA |
1583 | cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
1584 | struct request *rq) | |
22e2c507 | 1585 | { |
5e705374 | 1586 | struct cfq_io_context *cic = RQ_CIC(rq); |
12e9fddd | 1587 | |
21183b07 | 1588 | /* |
5380a101 | 1589 | * check if this request is a better next-serve candidate)) { |
21183b07 | 1590 | */ |
5e705374 JA |
1591 | cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq); |
1592 | BUG_ON(!cfqq->next_rq); | |
21183b07 | 1593 | |
9c2c38a1 JA |
1594 | /* |
1595 | * we never wait for an async request and we don't allow preemption | |
1596 | * of an async request. so just return early | |
1597 | */ | |
5e705374 | 1598 | if (!rq_is_sync(rq)) { |
12e9fddd JA |
1599 | /* |
1600 | * sync process issued an async request, if it's waiting | |
1601 | * then expire it and kick rq handling. | |
1602 | */ | |
1603 | if (cic == cfqd->active_cic && | |
1604 | del_timer(&cfqd->idle_slice_timer)) { | |
1605 | cfq_slice_expired(cfqd, 0); | |
1606 | cfq_start_queueing(cfqd, cfqq); | |
1607 | } | |
9c2c38a1 | 1608 | return; |
12e9fddd | 1609 | } |
22e2c507 | 1610 | |
9c2c38a1 | 1611 | cfq_update_io_thinktime(cfqd, cic); |
5e705374 | 1612 | cfq_update_io_seektime(cfqd, cic, rq); |
9c2c38a1 JA |
1613 | cfq_update_idle_window(cfqd, cfqq, cic); |
1614 | ||
1615 | cic->last_queue = jiffies; | |
5e705374 | 1616 | cic->last_request_pos = rq->sector + rq->nr_sectors; |
22e2c507 JA |
1617 | |
1618 | if (cfqq == cfqd->active_queue) { | |
1619 | /* | |
1620 | * if we are waiting for a request for this queue, let it rip | |
1621 | * immediately and flag that we must not expire this queue | |
1622 | * just now | |
1623 | */ | |
3b18152c JA |
1624 | if (cfq_cfqq_wait_request(cfqq)) { |
1625 | cfq_mark_cfqq_must_dispatch(cfqq); | |
22e2c507 JA |
1626 | del_timer(&cfqd->idle_slice_timer); |
1627 | cfq_start_queueing(cfqd, cfqq); | |
1628 | } | |
5e705374 | 1629 | } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
22e2c507 JA |
1630 | /* |
1631 | * not the active queue - expire current slice if it is | |
1632 | * idle and has expired it's mean thinktime or this new queue | |
1633 | * has some old slice time left and is of higher priority | |
1634 | */ | |
1635 | cfq_preempt_queue(cfqd, cfqq); | |
3b18152c | 1636 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
1637 | cfq_start_queueing(cfqd, cfqq); |
1638 | } | |
1da177e4 LT |
1639 | } |
1640 | ||
b4878f24 | 1641 | static void cfq_insert_request(request_queue_t *q, struct request *rq) |
1da177e4 | 1642 | { |
b4878f24 | 1643 | struct cfq_data *cfqd = q->elevator->elevator_data; |
5e705374 | 1644 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
22e2c507 JA |
1645 | |
1646 | cfq_init_prio_data(cfqq); | |
1da177e4 | 1647 | |
5e705374 | 1648 | cfq_add_rq_rb(rq); |
1da177e4 | 1649 | |
21183b07 JA |
1650 | if (!cfq_cfqq_on_rr(cfqq)) |
1651 | cfq_add_cfqq_rr(cfqd, cfqq); | |
1652 | ||
22e2c507 JA |
1653 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
1654 | ||
5e705374 | 1655 | cfq_rq_enqueued(cfqd, cfqq, rq); |
1da177e4 LT |
1656 | } |
1657 | ||
1da177e4 LT |
1658 | static void cfq_completed_request(request_queue_t *q, struct request *rq) |
1659 | { | |
5e705374 | 1660 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
b4878f24 | 1661 | struct cfq_data *cfqd = cfqq->cfqd; |
5380a101 | 1662 | const int sync = rq_is_sync(rq); |
b4878f24 | 1663 | unsigned long now; |
1da177e4 | 1664 | |
b4878f24 | 1665 | now = jiffies; |
1da177e4 | 1666 | |
b4878f24 JA |
1667 | WARN_ON(!cfqd->rq_in_driver); |
1668 | WARN_ON(!cfqq->on_dispatch[sync]); | |
1669 | cfqd->rq_in_driver--; | |
1670 | cfqq->on_dispatch[sync]--; | |
1da177e4 | 1671 | |
b4878f24 JA |
1672 | if (!cfq_class_idle(cfqq)) |
1673 | cfqd->last_end_request = now; | |
3b18152c | 1674 | |
b4878f24 JA |
1675 | if (!cfq_cfqq_dispatched(cfqq)) { |
1676 | if (cfq_cfqq_on_rr(cfqq)) { | |
1677 | cfqq->service_last = now; | |
1678 | cfq_resort_rr_list(cfqq, 0); | |
1679 | } | |
1da177e4 LT |
1680 | } |
1681 | ||
caaa5f9f | 1682 | if (sync) |
5e705374 | 1683 | RQ_CIC(rq)->last_end_request = now; |
caaa5f9f JA |
1684 | |
1685 | /* | |
1686 | * If this is the active queue, check if it needs to be expired, | |
1687 | * or if we want to idle in case it has no pending requests. | |
1688 | */ | |
1689 | if (cfqd->active_queue == cfqq) { | |
1690 | if (time_after(now, cfqq->slice_end)) | |
1691 | cfq_slice_expired(cfqd, 0); | |
dd67d051 | 1692 | else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
caaa5f9f JA |
1693 | if (!cfq_arm_slice_timer(cfqd, cfqq)) |
1694 | cfq_schedule_dispatch(cfqd); | |
1695 | } | |
1696 | } | |
1da177e4 LT |
1697 | } |
1698 | ||
22e2c507 JA |
1699 | /* |
1700 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
1701 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
1702 | */ | |
1703 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 1704 | { |
22e2c507 JA |
1705 | const int ioprio_class = cfqq->ioprio_class; |
1706 | const int ioprio = cfqq->ioprio; | |
1da177e4 | 1707 | |
22e2c507 JA |
1708 | if (has_fs_excl()) { |
1709 | /* | |
1710 | * boost idle prio on transactions that would lock out other | |
1711 | * users of the filesystem | |
1712 | */ | |
1713 | if (cfq_class_idle(cfqq)) | |
1714 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1715 | if (cfqq->ioprio > IOPRIO_NORM) | |
1716 | cfqq->ioprio = IOPRIO_NORM; | |
1717 | } else { | |
1718 | /* | |
1719 | * check if we need to unboost the queue | |
1720 | */ | |
1721 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) | |
1722 | cfqq->ioprio_class = cfqq->org_ioprio_class; | |
1723 | if (cfqq->ioprio != cfqq->org_ioprio) | |
1724 | cfqq->ioprio = cfqq->org_ioprio; | |
1725 | } | |
1da177e4 | 1726 | |
22e2c507 JA |
1727 | /* |
1728 | * refile between round-robin lists if we moved the priority class | |
1729 | */ | |
1730 | if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && | |
3b18152c | 1731 | cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1732 | cfq_resort_rr_list(cfqq, 0); |
1733 | } | |
1da177e4 | 1734 | |
89850f7e | 1735 | static inline int __cfq_may_queue(struct cfq_queue *cfqq) |
22e2c507 | 1736 | { |
3b18152c | 1737 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && |
99f95e52 | 1738 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1739 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1740 | return ELV_MQUEUE_MUST; |
3b18152c | 1741 | } |
1da177e4 | 1742 | |
22e2c507 | 1743 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
1744 | } |
1745 | ||
cb78b285 | 1746 | static int cfq_may_queue(request_queue_t *q, int rw) |
22e2c507 JA |
1747 | { |
1748 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1749 | struct task_struct *tsk = current; | |
1750 | struct cfq_queue *cfqq; | |
1751 | ||
1752 | /* | |
1753 | * don't force setup of a queue from here, as a call to may_queue | |
1754 | * does not necessarily imply that a request actually will be queued. | |
1755 | * so just lookup a possibly existing queue, or return 'may queue' | |
1756 | * if that fails | |
1757 | */ | |
3b18152c | 1758 | cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); |
22e2c507 JA |
1759 | if (cfqq) { |
1760 | cfq_init_prio_data(cfqq); | |
1761 | cfq_prio_boost(cfqq); | |
1762 | ||
89850f7e | 1763 | return __cfq_may_queue(cfqq); |
22e2c507 JA |
1764 | } |
1765 | ||
1766 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
1767 | } |
1768 | ||
1da177e4 LT |
1769 | /* |
1770 | * queue lock held here | |
1771 | */ | |
1772 | static void cfq_put_request(request_queue_t *q, struct request *rq) | |
1773 | { | |
5e705374 | 1774 | struct cfq_queue *cfqq = RQ_CFQQ(rq); |
1da177e4 | 1775 | |
5e705374 | 1776 | if (cfqq) { |
22e2c507 | 1777 | const int rw = rq_data_dir(rq); |
1da177e4 | 1778 | |
22e2c507 JA |
1779 | BUG_ON(!cfqq->allocated[rw]); |
1780 | cfqq->allocated[rw]--; | |
1da177e4 | 1781 | |
5e705374 | 1782 | put_io_context(RQ_CIC(rq)->ioc); |
1da177e4 | 1783 | |
1da177e4 | 1784 | rq->elevator_private = NULL; |
5e705374 | 1785 | rq->elevator_private2 = NULL; |
1da177e4 | 1786 | |
1da177e4 LT |
1787 | cfq_put_queue(cfqq); |
1788 | } | |
1789 | } | |
1790 | ||
1791 | /* | |
22e2c507 | 1792 | * Allocate cfq data structures associated with this request. |
1da177e4 | 1793 | */ |
22e2c507 | 1794 | static int |
cb78b285 | 1795 | cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask) |
1da177e4 LT |
1796 | { |
1797 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3b18152c | 1798 | struct task_struct *tsk = current; |
1da177e4 LT |
1799 | struct cfq_io_context *cic; |
1800 | const int rw = rq_data_dir(rq); | |
3b18152c | 1801 | pid_t key = cfq_queue_pid(tsk, rw); |
22e2c507 | 1802 | struct cfq_queue *cfqq; |
1da177e4 | 1803 | unsigned long flags; |
12a05732 | 1804 | int is_sync = key != CFQ_KEY_ASYNC; |
1da177e4 LT |
1805 | |
1806 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
1807 | ||
e2d74ac0 | 1808 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 1809 | |
1da177e4 LT |
1810 | spin_lock_irqsave(q->queue_lock, flags); |
1811 | ||
22e2c507 JA |
1812 | if (!cic) |
1813 | goto queue_fail; | |
1814 | ||
12a05732 | 1815 | if (!cic->cfqq[is_sync]) { |
6f325a13 | 1816 | cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask); |
22e2c507 JA |
1817 | if (!cfqq) |
1818 | goto queue_fail; | |
1da177e4 | 1819 | |
12a05732 | 1820 | cic->cfqq[is_sync] = cfqq; |
22e2c507 | 1821 | } else |
12a05732 | 1822 | cfqq = cic->cfqq[is_sync]; |
1da177e4 LT |
1823 | |
1824 | cfqq->allocated[rw]++; | |
3b18152c | 1825 | cfq_clear_cfqq_must_alloc(cfqq); |
22e2c507 | 1826 | atomic_inc(&cfqq->ref); |
1da177e4 | 1827 | |
5e705374 | 1828 | spin_unlock_irqrestore(q->queue_lock, flags); |
3b18152c | 1829 | |
5e705374 JA |
1830 | rq->elevator_private = cic; |
1831 | rq->elevator_private2 = cfqq; | |
1832 | return 0; | |
1da177e4 | 1833 | |
22e2c507 JA |
1834 | queue_fail: |
1835 | if (cic) | |
1836 | put_io_context(cic->ioc); | |
89850f7e | 1837 | |
3b18152c | 1838 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
1839 | spin_unlock_irqrestore(q->queue_lock, flags); |
1840 | return 1; | |
1841 | } | |
1842 | ||
22e2c507 JA |
1843 | static void cfq_kick_queue(void *data) |
1844 | { | |
1845 | request_queue_t *q = data; | |
22e2c507 JA |
1846 | unsigned long flags; |
1847 | ||
1848 | spin_lock_irqsave(q->queue_lock, flags); | |
22e2c507 JA |
1849 | blk_remove_plug(q); |
1850 | q->request_fn(q); | |
1851 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1852 | } | |
1853 | ||
1854 | /* | |
1855 | * Timer running if the active_queue is currently idling inside its time slice | |
1856 | */ | |
1857 | static void cfq_idle_slice_timer(unsigned long data) | |
1858 | { | |
1859 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
1860 | struct cfq_queue *cfqq; | |
1861 | unsigned long flags; | |
1862 | ||
1863 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1864 | ||
1865 | if ((cfqq = cfqd->active_queue) != NULL) { | |
1866 | unsigned long now = jiffies; | |
1867 | ||
1868 | /* | |
1869 | * expired | |
1870 | */ | |
1871 | if (time_after(now, cfqq->slice_end)) | |
1872 | goto expire; | |
1873 | ||
1874 | /* | |
1875 | * only expire and reinvoke request handler, if there are | |
1876 | * other queues with pending requests | |
1877 | */ | |
caaa5f9f | 1878 | if (!cfqd->busy_queues) |
22e2c507 | 1879 | goto out_cont; |
22e2c507 JA |
1880 | |
1881 | /* | |
1882 | * not expired and it has a request pending, let it dispatch | |
1883 | */ | |
dd67d051 | 1884 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) { |
3b18152c | 1885 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
1886 | goto out_kick; |
1887 | } | |
1888 | } | |
1889 | expire: | |
1890 | cfq_slice_expired(cfqd, 0); | |
1891 | out_kick: | |
3b18152c | 1892 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
1893 | out_cont: |
1894 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1895 | } | |
1896 | ||
1897 | /* | |
1898 | * Timer running if an idle class queue is waiting for service | |
1899 | */ | |
1900 | static void cfq_idle_class_timer(unsigned long data) | |
1901 | { | |
1902 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
1903 | unsigned long flags, end; | |
1904 | ||
1905 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
1906 | ||
1907 | /* | |
1908 | * race with a non-idle queue, reset timer | |
1909 | */ | |
1910 | end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
ae818a38 JA |
1911 | if (!time_after_eq(jiffies, end)) |
1912 | mod_timer(&cfqd->idle_class_timer, end); | |
1913 | else | |
3b18152c | 1914 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
1915 | |
1916 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
1917 | } | |
1918 | ||
3b18152c JA |
1919 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
1920 | { | |
1921 | del_timer_sync(&cfqd->idle_slice_timer); | |
1922 | del_timer_sync(&cfqd->idle_class_timer); | |
1923 | blk_sync_queue(cfqd->queue); | |
1924 | } | |
22e2c507 | 1925 | |
1da177e4 LT |
1926 | static void cfq_exit_queue(elevator_t *e) |
1927 | { | |
22e2c507 | 1928 | struct cfq_data *cfqd = e->elevator_data; |
d9ff4187 | 1929 | request_queue_t *q = cfqd->queue; |
22e2c507 | 1930 | |
3b18152c | 1931 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 1932 | |
d9ff4187 | 1933 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 1934 | |
d9ff4187 AV |
1935 | if (cfqd->active_queue) |
1936 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); | |
e2d74ac0 JA |
1937 | |
1938 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
1939 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
1940 | struct cfq_io_context, | |
1941 | queue_list); | |
89850f7e JA |
1942 | |
1943 | __cfq_exit_single_io_context(cfqd, cic); | |
d9ff4187 | 1944 | } |
e2d74ac0 | 1945 | |
d9ff4187 | 1946 | spin_unlock_irq(q->queue_lock); |
a90d742e AV |
1947 | |
1948 | cfq_shutdown_timer_wq(cfqd); | |
1949 | ||
a90d742e AV |
1950 | kfree(cfqd->cfq_hash); |
1951 | kfree(cfqd); | |
1da177e4 LT |
1952 | } |
1953 | ||
bc1c1169 | 1954 | static void *cfq_init_queue(request_queue_t *q, elevator_t *e) |
1da177e4 LT |
1955 | { |
1956 | struct cfq_data *cfqd; | |
1957 | int i; | |
1958 | ||
b5deef90 | 1959 | cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node); |
1da177e4 | 1960 | if (!cfqd) |
bc1c1169 | 1961 | return NULL; |
1da177e4 LT |
1962 | |
1963 | memset(cfqd, 0, sizeof(*cfqd)); | |
22e2c507 JA |
1964 | |
1965 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
1966 | INIT_LIST_HEAD(&cfqd->rr_list[i]); | |
1967 | ||
1968 | INIT_LIST_HEAD(&cfqd->busy_rr); | |
1969 | INIT_LIST_HEAD(&cfqd->cur_rr); | |
1970 | INIT_LIST_HEAD(&cfqd->idle_rr); | |
1da177e4 | 1971 | INIT_LIST_HEAD(&cfqd->empty_list); |
d9ff4187 | 1972 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 1973 | |
b5deef90 | 1974 | cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node); |
1da177e4 | 1975 | if (!cfqd->cfq_hash) |
5e705374 | 1976 | goto out_free; |
1da177e4 | 1977 | |
1da177e4 LT |
1978 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) |
1979 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); | |
1980 | ||
1da177e4 | 1981 | cfqd->queue = q; |
1da177e4 | 1982 | |
22e2c507 JA |
1983 | init_timer(&cfqd->idle_slice_timer); |
1984 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
1985 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
1986 | ||
1987 | init_timer(&cfqd->idle_class_timer); | |
1988 | cfqd->idle_class_timer.function = cfq_idle_class_timer; | |
1989 | cfqd->idle_class_timer.data = (unsigned long) cfqd; | |
1990 | ||
1991 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); | |
1992 | ||
1da177e4 | 1993 | cfqd->cfq_quantum = cfq_quantum; |
22e2c507 JA |
1994 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
1995 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
1996 | cfqd->cfq_back_max = cfq_back_max; |
1997 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
1998 | cfqd->cfq_slice[0] = cfq_slice_async; |
1999 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
2000 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
2001 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
3b18152c | 2002 | |
bc1c1169 | 2003 | return cfqd; |
5e705374 | 2004 | out_free: |
1da177e4 | 2005 | kfree(cfqd); |
bc1c1169 | 2006 | return NULL; |
1da177e4 LT |
2007 | } |
2008 | ||
2009 | static void cfq_slab_kill(void) | |
2010 | { | |
1da177e4 LT |
2011 | if (cfq_pool) |
2012 | kmem_cache_destroy(cfq_pool); | |
2013 | if (cfq_ioc_pool) | |
2014 | kmem_cache_destroy(cfq_ioc_pool); | |
2015 | } | |
2016 | ||
2017 | static int __init cfq_slab_setup(void) | |
2018 | { | |
1da177e4 LT |
2019 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, |
2020 | NULL, NULL); | |
2021 | if (!cfq_pool) | |
2022 | goto fail; | |
2023 | ||
2024 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", | |
2025 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); | |
2026 | if (!cfq_ioc_pool) | |
2027 | goto fail; | |
2028 | ||
2029 | return 0; | |
2030 | fail: | |
2031 | cfq_slab_kill(); | |
2032 | return -ENOMEM; | |
2033 | } | |
2034 | ||
1da177e4 LT |
2035 | /* |
2036 | * sysfs parts below --> | |
2037 | */ | |
1da177e4 LT |
2038 | |
2039 | static ssize_t | |
2040 | cfq_var_show(unsigned int var, char *page) | |
2041 | { | |
2042 | return sprintf(page, "%d\n", var); | |
2043 | } | |
2044 | ||
2045 | static ssize_t | |
2046 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
2047 | { | |
2048 | char *p = (char *) page; | |
2049 | ||
2050 | *var = simple_strtoul(p, &p, 10); | |
2051 | return count; | |
2052 | } | |
2053 | ||
1da177e4 | 2054 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
3d1ab40f | 2055 | static ssize_t __FUNC(elevator_t *e, char *page) \ |
1da177e4 | 2056 | { \ |
3d1ab40f | 2057 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
2058 | unsigned int __data = __VAR; \ |
2059 | if (__CONV) \ | |
2060 | __data = jiffies_to_msecs(__data); \ | |
2061 | return cfq_var_show(__data, (page)); \ | |
2062 | } | |
2063 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
22e2c507 JA |
2064 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
2065 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
2066 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
2067 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
2068 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
2069 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
2070 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
2071 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
1da177e4 LT |
2072 | #undef SHOW_FUNCTION |
2073 | ||
2074 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
3d1ab40f | 2075 | static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ |
1da177e4 | 2076 | { \ |
3d1ab40f | 2077 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
2078 | unsigned int __data; \ |
2079 | int ret = cfq_var_store(&__data, (page), count); \ | |
2080 | if (__data < (MIN)) \ | |
2081 | __data = (MIN); \ | |
2082 | else if (__data > (MAX)) \ | |
2083 | __data = (MAX); \ | |
2084 | if (__CONV) \ | |
2085 | *(__PTR) = msecs_to_jiffies(__data); \ | |
2086 | else \ | |
2087 | *(__PTR) = __data; \ | |
2088 | return ret; \ | |
2089 | } | |
2090 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
22e2c507 JA |
2091 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); |
2092 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); | |
e572ec7e AV |
2093 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
2094 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); | |
22e2c507 JA |
2095 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
2096 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
2097 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
2098 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); | |
1da177e4 LT |
2099 | #undef STORE_FUNCTION |
2100 | ||
e572ec7e AV |
2101 | #define CFQ_ATTR(name) \ |
2102 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
2103 | ||
2104 | static struct elv_fs_entry cfq_attrs[] = { | |
2105 | CFQ_ATTR(quantum), | |
e572ec7e AV |
2106 | CFQ_ATTR(fifo_expire_sync), |
2107 | CFQ_ATTR(fifo_expire_async), | |
2108 | CFQ_ATTR(back_seek_max), | |
2109 | CFQ_ATTR(back_seek_penalty), | |
2110 | CFQ_ATTR(slice_sync), | |
2111 | CFQ_ATTR(slice_async), | |
2112 | CFQ_ATTR(slice_async_rq), | |
2113 | CFQ_ATTR(slice_idle), | |
e572ec7e | 2114 | __ATTR_NULL |
1da177e4 LT |
2115 | }; |
2116 | ||
1da177e4 LT |
2117 | static struct elevator_type iosched_cfq = { |
2118 | .ops = { | |
2119 | .elevator_merge_fn = cfq_merge, | |
2120 | .elevator_merged_fn = cfq_merged_request, | |
2121 | .elevator_merge_req_fn = cfq_merged_requests, | |
b4878f24 | 2122 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 2123 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 2124 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
2125 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
2126 | .elevator_queue_empty_fn = cfq_queue_empty, | |
2127 | .elevator_completed_req_fn = cfq_completed_request, | |
21183b07 JA |
2128 | .elevator_former_req_fn = elv_rb_former_request, |
2129 | .elevator_latter_req_fn = elv_rb_latter_request, | |
1da177e4 LT |
2130 | .elevator_set_req_fn = cfq_set_request, |
2131 | .elevator_put_req_fn = cfq_put_request, | |
2132 | .elevator_may_queue_fn = cfq_may_queue, | |
2133 | .elevator_init_fn = cfq_init_queue, | |
2134 | .elevator_exit_fn = cfq_exit_queue, | |
fc46379d | 2135 | .trim = cfq_free_io_context, |
1da177e4 | 2136 | }, |
3d1ab40f | 2137 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
2138 | .elevator_name = "cfq", |
2139 | .elevator_owner = THIS_MODULE, | |
2140 | }; | |
2141 | ||
2142 | static int __init cfq_init(void) | |
2143 | { | |
2144 | int ret; | |
2145 | ||
22e2c507 JA |
2146 | /* |
2147 | * could be 0 on HZ < 1000 setups | |
2148 | */ | |
2149 | if (!cfq_slice_async) | |
2150 | cfq_slice_async = 1; | |
2151 | if (!cfq_slice_idle) | |
2152 | cfq_slice_idle = 1; | |
2153 | ||
1da177e4 LT |
2154 | if (cfq_slab_setup()) |
2155 | return -ENOMEM; | |
2156 | ||
2157 | ret = elv_register(&iosched_cfq); | |
22e2c507 JA |
2158 | if (ret) |
2159 | cfq_slab_kill(); | |
1da177e4 | 2160 | |
1da177e4 LT |
2161 | return ret; |
2162 | } | |
2163 | ||
2164 | static void __exit cfq_exit(void) | |
2165 | { | |
334e94de | 2166 | DECLARE_COMPLETION(all_gone); |
1da177e4 | 2167 | elv_unregister(&iosched_cfq); |
334e94de | 2168 | ioc_gone = &all_gone; |
fba82272 OH |
2169 | /* ioc_gone's update must be visible before reading ioc_count */ |
2170 | smp_wmb(); | |
4050cf16 | 2171 | if (elv_ioc_count_read(ioc_count)) |
fba82272 | 2172 | wait_for_completion(ioc_gone); |
334e94de | 2173 | synchronize_rcu(); |
83521d3e | 2174 | cfq_slab_kill(); |
1da177e4 LT |
2175 | } |
2176 | ||
2177 | module_init(cfq_init); | |
2178 | module_exit(cfq_exit); | |
2179 | ||
2180 | MODULE_AUTHOR("Jens Axboe"); | |
2181 | MODULE_LICENSE("GPL"); | |
2182 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |