Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * CFQ, or complete fairness queueing, disk scheduler. |
3 | * | |
4 | * Based on ideas from a previously unfinished io | |
5 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. | |
6 | * | |
7 | * Copyright (C) 2003 Jens Axboe <axboe@suse.de> | |
8 | */ | |
1da177e4 | 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 | 44 | #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) |
22e2c507 | 45 | #define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
1da177e4 LT |
46 | |
47 | #define RQ_DATA(rq) (rq)->elevator_private | |
48 | ||
49 | /* | |
50 | * rb-tree defines | |
51 | */ | |
1da177e4 LT |
52 | #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) |
53 | #define rq_rb_key(rq) (rq)->sector | |
54 | ||
1da177e4 LT |
55 | static kmem_cache_t *crq_pool; |
56 | static kmem_cache_t *cfq_pool; | |
57 | static kmem_cache_t *cfq_ioc_pool; | |
58 | ||
334e94de AV |
59 | static atomic_t ioc_count = ATOMIC_INIT(0); |
60 | static struct completion *ioc_gone; | |
61 | ||
22e2c507 JA |
62 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
63 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
64 | #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) | |
65 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) | |
66 | ||
3b18152c JA |
67 | #define ASYNC (0) |
68 | #define SYNC (1) | |
69 | ||
70 | #define cfq_cfqq_dispatched(cfqq) \ | |
71 | ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) | |
72 | ||
73 | #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) | |
74 | ||
75 | #define cfq_cfqq_sync(cfqq) \ | |
76 | (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) | |
22e2c507 | 77 | |
206dc69b JA |
78 | #define sample_valid(samples) ((samples) > 80) |
79 | ||
22e2c507 JA |
80 | /* |
81 | * Per block device queue structure | |
82 | */ | |
1da177e4 | 83 | struct cfq_data { |
22e2c507 JA |
84 | request_queue_t *queue; |
85 | ||
86 | /* | |
87 | * rr list of queues with requests and the count of them | |
88 | */ | |
89 | struct list_head rr_list[CFQ_PRIO_LISTS]; | |
90 | struct list_head busy_rr; | |
91 | struct list_head cur_rr; | |
92 | struct list_head idle_rr; | |
93 | unsigned int busy_queues; | |
94 | ||
95 | /* | |
96 | * non-ordered list of empty cfqq's | |
97 | */ | |
1da177e4 LT |
98 | struct list_head empty_list; |
99 | ||
22e2c507 JA |
100 | /* |
101 | * cfqq lookup hash | |
102 | */ | |
1da177e4 | 103 | struct hlist_head *cfq_hash; |
1da177e4 | 104 | |
22e2c507 | 105 | mempool_t *crq_pool; |
1da177e4 | 106 | |
22e2c507 | 107 | int rq_in_driver; |
25776e35 | 108 | int hw_tag; |
1da177e4 | 109 | |
22e2c507 JA |
110 | /* |
111 | * schedule slice state info | |
112 | */ | |
113 | /* | |
114 | * idle window management | |
115 | */ | |
116 | struct timer_list idle_slice_timer; | |
117 | struct work_struct unplug_work; | |
1da177e4 | 118 | |
22e2c507 JA |
119 | struct cfq_queue *active_queue; |
120 | struct cfq_io_context *active_cic; | |
121 | int cur_prio, cur_end_prio; | |
122 | unsigned int dispatch_slice; | |
123 | ||
124 | struct timer_list idle_class_timer; | |
1da177e4 LT |
125 | |
126 | sector_t last_sector; | |
22e2c507 | 127 | unsigned long last_end_request; |
1da177e4 | 128 | |
22e2c507 | 129 | unsigned int rq_starved; |
1da177e4 LT |
130 | |
131 | /* | |
132 | * tunables, see top of file | |
133 | */ | |
134 | unsigned int cfq_quantum; | |
135 | unsigned int cfq_queued; | |
22e2c507 | 136 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
137 | unsigned int cfq_back_penalty; |
138 | unsigned int cfq_back_max; | |
22e2c507 JA |
139 | unsigned int cfq_slice[2]; |
140 | unsigned int cfq_slice_async_rq; | |
141 | unsigned int cfq_slice_idle; | |
d9ff4187 AV |
142 | |
143 | struct list_head cic_list; | |
1da177e4 LT |
144 | }; |
145 | ||
22e2c507 JA |
146 | /* |
147 | * Per process-grouping structure | |
148 | */ | |
1da177e4 LT |
149 | struct cfq_queue { |
150 | /* reference count */ | |
151 | atomic_t ref; | |
152 | /* parent cfq_data */ | |
153 | struct cfq_data *cfqd; | |
22e2c507 | 154 | /* cfqq lookup hash */ |
1da177e4 LT |
155 | struct hlist_node cfq_hash; |
156 | /* hash key */ | |
22e2c507 | 157 | unsigned int key; |
1da177e4 LT |
158 | /* on either rr or empty list of cfqd */ |
159 | struct list_head cfq_list; | |
160 | /* sorted list of pending requests */ | |
161 | struct rb_root sort_list; | |
162 | /* if fifo isn't expired, next request to serve */ | |
163 | struct cfq_rq *next_crq; | |
164 | /* requests queued in sort_list */ | |
165 | int queued[2]; | |
166 | /* currently allocated requests */ | |
167 | int allocated[2]; | |
168 | /* fifo list of requests in sort_list */ | |
22e2c507 | 169 | struct list_head fifo; |
1da177e4 | 170 | |
22e2c507 JA |
171 | unsigned long slice_start; |
172 | unsigned long slice_end; | |
173 | unsigned long slice_left; | |
174 | unsigned long service_last; | |
1da177e4 | 175 | |
3b18152c JA |
176 | /* number of requests that are on the dispatch list */ |
177 | int on_dispatch[2]; | |
22e2c507 JA |
178 | |
179 | /* io prio of this group */ | |
180 | unsigned short ioprio, org_ioprio; | |
181 | unsigned short ioprio_class, org_ioprio_class; | |
182 | ||
3b18152c JA |
183 | /* various state flags, see below */ |
184 | unsigned int flags; | |
1da177e4 LT |
185 | }; |
186 | ||
187 | struct cfq_rq { | |
188 | struct rb_node rb_node; | |
189 | sector_t rb_key; | |
190 | struct request *request; | |
1da177e4 LT |
191 | |
192 | struct cfq_queue *cfq_queue; | |
193 | struct cfq_io_context *io_context; | |
194 | ||
3b18152c | 195 | unsigned int crq_flags; |
1da177e4 LT |
196 | }; |
197 | ||
3b18152c JA |
198 | enum cfqq_state_flags { |
199 | CFQ_CFQQ_FLAG_on_rr = 0, | |
200 | CFQ_CFQQ_FLAG_wait_request, | |
201 | CFQ_CFQQ_FLAG_must_alloc, | |
202 | CFQ_CFQQ_FLAG_must_alloc_slice, | |
203 | CFQ_CFQQ_FLAG_must_dispatch, | |
204 | CFQ_CFQQ_FLAG_fifo_expire, | |
205 | CFQ_CFQQ_FLAG_idle_window, | |
206 | CFQ_CFQQ_FLAG_prio_changed, | |
3b18152c JA |
207 | }; |
208 | ||
209 | #define CFQ_CFQQ_FNS(name) \ | |
210 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
211 | { \ | |
212 | cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ | |
213 | } \ | |
214 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
215 | { \ | |
216 | cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ | |
217 | } \ | |
218 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
219 | { \ | |
220 | return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ | |
221 | } | |
222 | ||
223 | CFQ_CFQQ_FNS(on_rr); | |
224 | CFQ_CFQQ_FNS(wait_request); | |
225 | CFQ_CFQQ_FNS(must_alloc); | |
226 | CFQ_CFQQ_FNS(must_alloc_slice); | |
227 | CFQ_CFQQ_FNS(must_dispatch); | |
228 | CFQ_CFQQ_FNS(fifo_expire); | |
229 | CFQ_CFQQ_FNS(idle_window); | |
230 | CFQ_CFQQ_FNS(prio_changed); | |
3b18152c JA |
231 | #undef CFQ_CFQQ_FNS |
232 | ||
233 | enum cfq_rq_state_flags { | |
b4878f24 | 234 | CFQ_CRQ_FLAG_is_sync = 0, |
3b18152c JA |
235 | }; |
236 | ||
237 | #define CFQ_CRQ_FNS(name) \ | |
238 | static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \ | |
239 | { \ | |
240 | crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \ | |
241 | } \ | |
242 | static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \ | |
243 | { \ | |
244 | crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \ | |
245 | } \ | |
246 | static inline int cfq_crq_##name(const struct cfq_rq *crq) \ | |
247 | { \ | |
248 | return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \ | |
249 | } | |
250 | ||
3b18152c | 251 | CFQ_CRQ_FNS(is_sync); |
3b18152c JA |
252 | #undef CFQ_CRQ_FNS |
253 | ||
254 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); | |
b4878f24 | 255 | static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); |
6f325a13 | 256 | static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); |
1da177e4 | 257 | |
99f95e52 AM |
258 | /* |
259 | * scheduler run of queue, if there are requests pending and no one in the | |
260 | * driver that will restart queueing | |
261 | */ | |
262 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) | |
263 | { | |
7b14e3b5 | 264 | if (cfqd->busy_queues) |
99f95e52 AM |
265 | kblockd_schedule_work(&cfqd->unplug_work); |
266 | } | |
267 | ||
268 | static int cfq_queue_empty(request_queue_t *q) | |
269 | { | |
270 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
271 | ||
b4878f24 | 272 | return !cfqd->busy_queues; |
99f95e52 AM |
273 | } |
274 | ||
206dc69b JA |
275 | static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
276 | { | |
b31dc66a | 277 | if (rw == READ || rw == WRITE_SYNC) |
206dc69b JA |
278 | return task->pid; |
279 | ||
280 | return CFQ_KEY_ASYNC; | |
281 | } | |
282 | ||
1da177e4 LT |
283 | /* |
284 | * Lifted from AS - choose which of crq1 and crq2 that is best served now. | |
285 | * We choose the request that is closest to the head right now. Distance | |
e8a99053 | 286 | * behind the head is penalized and only allowed to a certain extent. |
1da177e4 LT |
287 | */ |
288 | static struct cfq_rq * | |
289 | cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) | |
290 | { | |
291 | sector_t last, s1, s2, d1 = 0, d2 = 0; | |
1da177e4 | 292 | unsigned long back_max; |
e8a99053 AM |
293 | #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
294 | #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ | |
295 | unsigned wrap = 0; /* bit mask: requests behind the disk head? */ | |
1da177e4 LT |
296 | |
297 | if (crq1 == NULL || crq1 == crq2) | |
298 | return crq2; | |
299 | if (crq2 == NULL) | |
300 | return crq1; | |
9c2c38a1 | 301 | |
9c2c38a1 JA |
302 | if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2)) |
303 | return crq1; | |
304 | else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1)) | |
22e2c507 | 305 | return crq2; |
1da177e4 LT |
306 | |
307 | s1 = crq1->request->sector; | |
308 | s2 = crq2->request->sector; | |
309 | ||
310 | last = cfqd->last_sector; | |
311 | ||
1da177e4 LT |
312 | /* |
313 | * by definition, 1KiB is 2 sectors | |
314 | */ | |
315 | back_max = cfqd->cfq_back_max * 2; | |
316 | ||
317 | /* | |
318 | * Strict one way elevator _except_ in the case where we allow | |
319 | * short backward seeks which are biased as twice the cost of a | |
320 | * similar forward seek. | |
321 | */ | |
322 | if (s1 >= last) | |
323 | d1 = s1 - last; | |
324 | else if (s1 + back_max >= last) | |
325 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
326 | else | |
e8a99053 | 327 | wrap |= CFQ_RQ1_WRAP; |
1da177e4 LT |
328 | |
329 | if (s2 >= last) | |
330 | d2 = s2 - last; | |
331 | else if (s2 + back_max >= last) | |
332 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
333 | else | |
e8a99053 | 334 | wrap |= CFQ_RQ2_WRAP; |
1da177e4 LT |
335 | |
336 | /* Found required data */ | |
e8a99053 AM |
337 | |
338 | /* | |
339 | * By doing switch() on the bit mask "wrap" we avoid having to | |
340 | * check two variables for all permutations: --> faster! | |
341 | */ | |
342 | switch (wrap) { | |
343 | case 0: /* common case for CFQ: crq1 and crq2 not wrapped */ | |
344 | if (d1 < d2) | |
1da177e4 | 345 | return crq1; |
e8a99053 | 346 | else if (d2 < d1) |
1da177e4 | 347 | return crq2; |
e8a99053 AM |
348 | else { |
349 | if (s1 >= s2) | |
350 | return crq1; | |
351 | else | |
352 | return crq2; | |
353 | } | |
1da177e4 | 354 | |
e8a99053 | 355 | case CFQ_RQ2_WRAP: |
1da177e4 | 356 | return crq1; |
e8a99053 | 357 | case CFQ_RQ1_WRAP: |
1da177e4 | 358 | return crq2; |
e8a99053 AM |
359 | case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both crqs wrapped */ |
360 | default: | |
361 | /* | |
362 | * Since both rqs are wrapped, | |
363 | * start with the one that's further behind head | |
364 | * (--> only *one* back seek required), | |
365 | * since back seek takes more time than forward. | |
366 | */ | |
367 | if (s1 <= s2) | |
1da177e4 LT |
368 | return crq1; |
369 | else | |
370 | return crq2; | |
371 | } | |
372 | } | |
373 | ||
374 | /* | |
375 | * would be nice to take fifo expire time into account as well | |
376 | */ | |
377 | static struct cfq_rq * | |
378 | cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
379 | struct cfq_rq *last) | |
380 | { | |
381 | struct cfq_rq *crq_next = NULL, *crq_prev = NULL; | |
382 | struct rb_node *rbnext, *rbprev; | |
383 | ||
b4878f24 | 384 | if (!(rbnext = rb_next(&last->rb_node))) { |
1da177e4 | 385 | rbnext = rb_first(&cfqq->sort_list); |
22e2c507 JA |
386 | if (rbnext == &last->rb_node) |
387 | rbnext = NULL; | |
388 | } | |
1da177e4 LT |
389 | |
390 | rbprev = rb_prev(&last->rb_node); | |
391 | ||
392 | if (rbprev) | |
393 | crq_prev = rb_entry_crq(rbprev); | |
394 | if (rbnext) | |
395 | crq_next = rb_entry_crq(rbnext); | |
396 | ||
397 | return cfq_choose_req(cfqd, crq_next, crq_prev); | |
398 | } | |
399 | ||
400 | static void cfq_update_next_crq(struct cfq_rq *crq) | |
401 | { | |
402 | struct cfq_queue *cfqq = crq->cfq_queue; | |
403 | ||
404 | if (cfqq->next_crq == crq) | |
405 | cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); | |
406 | } | |
407 | ||
22e2c507 | 408 | static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
1da177e4 | 409 | { |
22e2c507 JA |
410 | struct cfq_data *cfqd = cfqq->cfqd; |
411 | struct list_head *list, *entry; | |
1da177e4 | 412 | |
3b18152c | 413 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 414 | |
22e2c507 | 415 | list_del(&cfqq->cfq_list); |
1da177e4 | 416 | |
22e2c507 JA |
417 | if (cfq_class_rt(cfqq)) |
418 | list = &cfqd->cur_rr; | |
419 | else if (cfq_class_idle(cfqq)) | |
420 | list = &cfqd->idle_rr; | |
421 | else { | |
422 | /* | |
423 | * if cfqq has requests in flight, don't allow it to be | |
424 | * found in cfq_set_active_queue before it has finished them. | |
425 | * this is done to increase fairness between a process that | |
426 | * has lots of io pending vs one that only generates one | |
427 | * sporadically or synchronously | |
428 | */ | |
3b18152c | 429 | if (cfq_cfqq_dispatched(cfqq)) |
22e2c507 JA |
430 | list = &cfqd->busy_rr; |
431 | else | |
432 | list = &cfqd->rr_list[cfqq->ioprio]; | |
1da177e4 LT |
433 | } |
434 | ||
22e2c507 JA |
435 | /* |
436 | * if queue was preempted, just add to front to be fair. busy_rr | |
b52a8348 | 437 | * isn't sorted, but insert at the back for fairness. |
22e2c507 JA |
438 | */ |
439 | if (preempted || list == &cfqd->busy_rr) { | |
b52a8348 JA |
440 | if (preempted) |
441 | list = list->prev; | |
442 | ||
443 | list_add_tail(&cfqq->cfq_list, list); | |
1da177e4 | 444 | return; |
22e2c507 | 445 | } |
1da177e4 LT |
446 | |
447 | /* | |
22e2c507 | 448 | * sort by when queue was last serviced |
1da177e4 | 449 | */ |
22e2c507 JA |
450 | entry = list; |
451 | while ((entry = entry->prev) != list) { | |
1da177e4 LT |
452 | struct cfq_queue *__cfqq = list_entry_cfqq(entry); |
453 | ||
22e2c507 JA |
454 | if (!__cfqq->service_last) |
455 | break; | |
456 | if (time_before(__cfqq->service_last, cfqq->service_last)) | |
1da177e4 | 457 | break; |
1da177e4 LT |
458 | } |
459 | ||
460 | list_add(&cfqq->cfq_list, entry); | |
461 | } | |
462 | ||
463 | /* | |
464 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 465 | * the pending list according to last request service |
1da177e4 LT |
466 | */ |
467 | static inline void | |
b4878f24 | 468 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 469 | { |
3b18152c JA |
470 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
471 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
472 | cfqd->busy_queues++; |
473 | ||
b4878f24 | 474 | cfq_resort_rr_list(cfqq, 0); |
1da177e4 LT |
475 | } |
476 | ||
477 | static inline void | |
478 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
479 | { | |
3b18152c JA |
480 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
481 | cfq_clear_cfqq_on_rr(cfqq); | |
22e2c507 | 482 | list_move(&cfqq->cfq_list, &cfqd->empty_list); |
1da177e4 LT |
483 | |
484 | BUG_ON(!cfqd->busy_queues); | |
485 | cfqd->busy_queues--; | |
486 | } | |
487 | ||
488 | /* | |
489 | * rb tree support functions | |
490 | */ | |
491 | static inline void cfq_del_crq_rb(struct cfq_rq *crq) | |
492 | { | |
493 | struct cfq_queue *cfqq = crq->cfq_queue; | |
b4878f24 JA |
494 | struct cfq_data *cfqd = cfqq->cfqd; |
495 | const int sync = cfq_crq_is_sync(crq); | |
1da177e4 | 496 | |
b4878f24 JA |
497 | BUG_ON(!cfqq->queued[sync]); |
498 | cfqq->queued[sync]--; | |
1da177e4 | 499 | |
b4878f24 | 500 | cfq_update_next_crq(crq); |
1da177e4 | 501 | |
b4878f24 | 502 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
1da177e4 | 503 | |
dd67d051 | 504 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
b4878f24 | 505 | cfq_del_cfqq_rr(cfqd, cfqq); |
1da177e4 LT |
506 | } |
507 | ||
508 | static struct cfq_rq * | |
509 | __cfq_add_crq_rb(struct cfq_rq *crq) | |
510 | { | |
511 | struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; | |
512 | struct rb_node *parent = NULL; | |
513 | struct cfq_rq *__crq; | |
514 | ||
515 | while (*p) { | |
516 | parent = *p; | |
517 | __crq = rb_entry_crq(parent); | |
518 | ||
519 | if (crq->rb_key < __crq->rb_key) | |
520 | p = &(*p)->rb_left; | |
521 | else if (crq->rb_key > __crq->rb_key) | |
522 | p = &(*p)->rb_right; | |
523 | else | |
524 | return __crq; | |
525 | } | |
526 | ||
527 | rb_link_node(&crq->rb_node, parent, p); | |
528 | return NULL; | |
529 | } | |
530 | ||
531 | static void cfq_add_crq_rb(struct cfq_rq *crq) | |
532 | { | |
533 | struct cfq_queue *cfqq = crq->cfq_queue; | |
534 | struct cfq_data *cfqd = cfqq->cfqd; | |
535 | struct request *rq = crq->request; | |
536 | struct cfq_rq *__alias; | |
537 | ||
538 | crq->rb_key = rq_rb_key(rq); | |
3b18152c | 539 | cfqq->queued[cfq_crq_is_sync(crq)]++; |
1da177e4 LT |
540 | |
541 | /* | |
542 | * looks a little odd, but the first insert might return an alias. | |
543 | * if that happens, put the alias on the dispatch list | |
544 | */ | |
545 | while ((__alias = __cfq_add_crq_rb(crq)) != NULL) | |
b4878f24 | 546 | cfq_dispatch_insert(cfqd->queue, __alias); |
1da177e4 LT |
547 | |
548 | rb_insert_color(&crq->rb_node, &cfqq->sort_list); | |
549 | ||
3b18152c | 550 | if (!cfq_cfqq_on_rr(cfqq)) |
b4878f24 | 551 | cfq_add_cfqq_rr(cfqd, cfqq); |
1da177e4 LT |
552 | |
553 | /* | |
554 | * check if this request is a better next-serve candidate | |
555 | */ | |
556 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
557 | } | |
558 | ||
559 | static inline void | |
560 | cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) | |
561 | { | |
b4878f24 JA |
562 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
563 | cfqq->queued[cfq_crq_is_sync(crq)]--; | |
1da177e4 LT |
564 | |
565 | cfq_add_crq_rb(crq); | |
566 | } | |
567 | ||
206dc69b JA |
568 | static struct request * |
569 | cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) | |
1da177e4 | 570 | { |
206dc69b JA |
571 | struct task_struct *tsk = current; |
572 | pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio)); | |
573 | struct cfq_queue *cfqq; | |
1da177e4 | 574 | struct rb_node *n; |
206dc69b | 575 | sector_t sector; |
1da177e4 | 576 | |
206dc69b | 577 | cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); |
1da177e4 LT |
578 | if (!cfqq) |
579 | goto out; | |
580 | ||
206dc69b | 581 | sector = bio->bi_sector + bio_sectors(bio); |
1da177e4 LT |
582 | n = cfqq->sort_list.rb_node; |
583 | while (n) { | |
584 | struct cfq_rq *crq = rb_entry_crq(n); | |
585 | ||
586 | if (sector < crq->rb_key) | |
587 | n = n->rb_left; | |
588 | else if (sector > crq->rb_key) | |
589 | n = n->rb_right; | |
590 | else | |
591 | return crq->request; | |
592 | } | |
593 | ||
594 | out: | |
595 | return NULL; | |
596 | } | |
597 | ||
b4878f24 | 598 | static void cfq_activate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 599 | { |
22e2c507 | 600 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 601 | |
b4878f24 | 602 | cfqd->rq_in_driver++; |
25776e35 JA |
603 | |
604 | /* | |
605 | * If the depth is larger 1, it really could be queueing. But lets | |
606 | * make the mark a little higher - idling could still be good for | |
607 | * low queueing, and a low queueing number could also just indicate | |
608 | * a SCSI mid layer like behaviour where limit+1 is often seen. | |
609 | */ | |
610 | if (!cfqd->hw_tag && cfqd->rq_in_driver > 4) | |
611 | cfqd->hw_tag = 1; | |
1da177e4 LT |
612 | } |
613 | ||
b4878f24 | 614 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 615 | { |
b4878f24 JA |
616 | struct cfq_data *cfqd = q->elevator->elevator_data; |
617 | ||
618 | WARN_ON(!cfqd->rq_in_driver); | |
619 | cfqd->rq_in_driver--; | |
1da177e4 LT |
620 | } |
621 | ||
b4878f24 | 622 | static void cfq_remove_request(struct request *rq) |
1da177e4 LT |
623 | { |
624 | struct cfq_rq *crq = RQ_DATA(rq); | |
625 | ||
b4878f24 JA |
626 | list_del_init(&rq->queuelist); |
627 | cfq_del_crq_rb(crq); | |
1da177e4 LT |
628 | } |
629 | ||
630 | static int | |
631 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
632 | { | |
633 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
634 | struct request *__rq; | |
1da177e4 | 635 | |
206dc69b | 636 | __rq = cfq_find_rq_fmerge(cfqd, bio); |
22e2c507 | 637 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
9817064b JA |
638 | *req = __rq; |
639 | return ELEVATOR_FRONT_MERGE; | |
1da177e4 LT |
640 | } |
641 | ||
642 | return ELEVATOR_NO_MERGE; | |
1da177e4 LT |
643 | } |
644 | ||
645 | static void cfq_merged_request(request_queue_t *q, struct request *req) | |
646 | { | |
1da177e4 LT |
647 | struct cfq_rq *crq = RQ_DATA(req); |
648 | ||
b4878f24 | 649 | if (rq_rb_key(req) != crq->rb_key) { |
1da177e4 LT |
650 | struct cfq_queue *cfqq = crq->cfq_queue; |
651 | ||
652 | cfq_update_next_crq(crq); | |
653 | cfq_reposition_crq_rb(cfqq, crq); | |
654 | } | |
1da177e4 LT |
655 | } |
656 | ||
657 | static void | |
658 | cfq_merged_requests(request_queue_t *q, struct request *rq, | |
659 | struct request *next) | |
660 | { | |
1da177e4 LT |
661 | cfq_merged_request(q, rq); |
662 | ||
22e2c507 JA |
663 | /* |
664 | * reposition in fifo if next is older than rq | |
665 | */ | |
666 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
667 | time_before(next->start_time, rq->start_time)) | |
668 | list_move(&rq->queuelist, &next->queuelist); | |
669 | ||
b4878f24 | 670 | cfq_remove_request(next); |
22e2c507 JA |
671 | } |
672 | ||
673 | static inline void | |
674 | __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
675 | { | |
676 | if (cfqq) { | |
677 | /* | |
678 | * stop potential idle class queues waiting service | |
679 | */ | |
680 | del_timer(&cfqd->idle_class_timer); | |
681 | ||
682 | cfqq->slice_start = jiffies; | |
683 | cfqq->slice_end = 0; | |
684 | cfqq->slice_left = 0; | |
3b18152c JA |
685 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
686 | cfq_clear_cfqq_fifo_expire(cfqq); | |
22e2c507 JA |
687 | } |
688 | ||
689 | cfqd->active_queue = cfqq; | |
690 | } | |
691 | ||
7b14e3b5 JA |
692 | /* |
693 | * current cfqq expired its slice (or was too idle), select new one | |
694 | */ | |
695 | static void | |
696 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
697 | int preempted) | |
698 | { | |
699 | unsigned long now = jiffies; | |
700 | ||
701 | if (cfq_cfqq_wait_request(cfqq)) | |
702 | del_timer(&cfqd->idle_slice_timer); | |
703 | ||
704 | if (!preempted && !cfq_cfqq_dispatched(cfqq)) { | |
705 | cfqq->service_last = now; | |
706 | cfq_schedule_dispatch(cfqd); | |
707 | } | |
708 | ||
709 | cfq_clear_cfqq_must_dispatch(cfqq); | |
710 | cfq_clear_cfqq_wait_request(cfqq); | |
711 | ||
712 | /* | |
713 | * store what was left of this slice, if the queue idled out | |
714 | * or was preempted | |
715 | */ | |
716 | if (time_after(cfqq->slice_end, now)) | |
717 | cfqq->slice_left = cfqq->slice_end - now; | |
718 | else | |
719 | cfqq->slice_left = 0; | |
720 | ||
721 | if (cfq_cfqq_on_rr(cfqq)) | |
722 | cfq_resort_rr_list(cfqq, preempted); | |
723 | ||
724 | if (cfqq == cfqd->active_queue) | |
725 | cfqd->active_queue = NULL; | |
726 | ||
727 | if (cfqd->active_cic) { | |
728 | put_io_context(cfqd->active_cic->ioc); | |
729 | cfqd->active_cic = NULL; | |
730 | } | |
731 | ||
732 | cfqd->dispatch_slice = 0; | |
733 | } | |
734 | ||
735 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) | |
736 | { | |
737 | struct cfq_queue *cfqq = cfqd->active_queue; | |
738 | ||
739 | if (cfqq) | |
740 | __cfq_slice_expired(cfqd, cfqq, preempted); | |
741 | } | |
742 | ||
22e2c507 JA |
743 | /* |
744 | * 0 | |
745 | * 0,1 | |
746 | * 0,1,2 | |
747 | * 0,1,2,3 | |
748 | * 0,1,2,3,4 | |
749 | * 0,1,2,3,4,5 | |
750 | * 0,1,2,3,4,5,6 | |
751 | * 0,1,2,3,4,5,6,7 | |
752 | */ | |
753 | static int cfq_get_next_prio_level(struct cfq_data *cfqd) | |
754 | { | |
755 | int prio, wrap; | |
756 | ||
757 | prio = -1; | |
758 | wrap = 0; | |
759 | do { | |
760 | int p; | |
761 | ||
762 | for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { | |
763 | if (!list_empty(&cfqd->rr_list[p])) { | |
764 | prio = p; | |
765 | break; | |
766 | } | |
767 | } | |
768 | ||
769 | if (prio != -1) | |
770 | break; | |
771 | cfqd->cur_prio = 0; | |
772 | if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
773 | cfqd->cur_end_prio = 0; | |
774 | if (wrap) | |
775 | break; | |
776 | wrap = 1; | |
1da177e4 | 777 | } |
22e2c507 JA |
778 | } while (1); |
779 | ||
780 | if (unlikely(prio == -1)) | |
781 | return -1; | |
782 | ||
783 | BUG_ON(prio >= CFQ_PRIO_LISTS); | |
784 | ||
785 | list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); | |
786 | ||
787 | cfqd->cur_prio = prio + 1; | |
788 | if (cfqd->cur_prio > cfqd->cur_end_prio) { | |
789 | cfqd->cur_end_prio = cfqd->cur_prio; | |
790 | cfqd->cur_prio = 0; | |
791 | } | |
792 | if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
793 | cfqd->cur_prio = 0; | |
794 | cfqd->cur_end_prio = 0; | |
1da177e4 LT |
795 | } |
796 | ||
22e2c507 JA |
797 | return prio; |
798 | } | |
799 | ||
3b18152c | 800 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
22e2c507 | 801 | { |
7b14e3b5 | 802 | struct cfq_queue *cfqq = NULL; |
22e2c507 JA |
803 | |
804 | /* | |
805 | * if current list is non-empty, grab first entry. if it is empty, | |
806 | * get next prio level and grab first entry then if any are spliced | |
807 | */ | |
808 | if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) | |
809 | cfqq = list_entry_cfqq(cfqd->cur_rr.next); | |
810 | ||
e0de0206 JA |
811 | /* |
812 | * If no new queues are available, check if the busy list has some | |
813 | * before falling back to idle io. | |
814 | */ | |
815 | if (!cfqq && !list_empty(&cfqd->busy_rr)) | |
816 | cfqq = list_entry_cfqq(cfqd->busy_rr.next); | |
817 | ||
22e2c507 JA |
818 | /* |
819 | * if we have idle queues and no rt or be queues had pending | |
820 | * requests, either allow immediate service if the grace period | |
821 | * has passed or arm the idle grace timer | |
822 | */ | |
823 | if (!cfqq && !list_empty(&cfqd->idle_rr)) { | |
824 | unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
825 | ||
826 | if (time_after_eq(jiffies, end)) | |
827 | cfqq = list_entry_cfqq(cfqd->idle_rr.next); | |
828 | else | |
829 | mod_timer(&cfqd->idle_class_timer, end); | |
830 | } | |
831 | ||
832 | __cfq_set_active_queue(cfqd, cfqq); | |
3b18152c | 833 | return cfqq; |
22e2c507 JA |
834 | } |
835 | ||
caaa5f9f JA |
836 | #define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024)) |
837 | ||
22e2c507 JA |
838 | static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
839 | ||
840 | { | |
206dc69b | 841 | struct cfq_io_context *cic; |
7b14e3b5 JA |
842 | unsigned long sl; |
843 | ||
dd67d051 | 844 | WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); |
22e2c507 JA |
845 | WARN_ON(cfqq != cfqd->active_queue); |
846 | ||
847 | /* | |
848 | * idle is disabled, either manually or by past process history | |
849 | */ | |
850 | if (!cfqd->cfq_slice_idle) | |
851 | return 0; | |
3b18152c | 852 | if (!cfq_cfqq_idle_window(cfqq)) |
22e2c507 JA |
853 | return 0; |
854 | /* | |
855 | * task has exited, don't wait | |
856 | */ | |
206dc69b JA |
857 | cic = cfqd->active_cic; |
858 | if (!cic || !cic->ioc->task) | |
22e2c507 JA |
859 | return 0; |
860 | ||
3b18152c JA |
861 | cfq_mark_cfqq_must_dispatch(cfqq); |
862 | cfq_mark_cfqq_wait_request(cfqq); | |
22e2c507 | 863 | |
7b14e3b5 | 864 | sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
206dc69b JA |
865 | |
866 | /* | |
867 | * we don't want to idle for seeks, but we do want to allow | |
868 | * fair distribution of slice time for a process doing back-to-back | |
869 | * seeks. so allow a little bit of time for him to submit a new rq | |
870 | */ | |
caaa5f9f | 871 | if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic)) |
44eb1231 | 872 | sl = min(sl, msecs_to_jiffies(2)); |
206dc69b | 873 | |
7b14e3b5 | 874 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
22e2c507 | 875 | return 1; |
1da177e4 LT |
876 | } |
877 | ||
b4878f24 | 878 | static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) |
1da177e4 LT |
879 | { |
880 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
881 | struct cfq_queue *cfqq = crq->cfq_queue; | |
fd61af03 | 882 | struct request *rq; |
22e2c507 JA |
883 | |
884 | cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); | |
b4878f24 | 885 | cfq_remove_request(crq->request); |
3b18152c | 886 | cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; |
b4878f24 | 887 | elv_dispatch_sort(q, crq->request); |
fd61af03 JA |
888 | |
889 | rq = list_entry(q->queue_head.prev, struct request, queuelist); | |
890 | cfqd->last_sector = rq->sector + rq->nr_sectors; | |
1da177e4 LT |
891 | } |
892 | ||
893 | /* | |
894 | * return expired entry, or NULL to just start from scratch in rbtree | |
895 | */ | |
896 | static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) | |
897 | { | |
898 | struct cfq_data *cfqd = cfqq->cfqd; | |
22e2c507 | 899 | struct request *rq; |
1da177e4 LT |
900 | struct cfq_rq *crq; |
901 | ||
3b18152c | 902 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 LT |
903 | return NULL; |
904 | ||
22e2c507 | 905 | if (!list_empty(&cfqq->fifo)) { |
3b18152c | 906 | int fifo = cfq_cfqq_class_sync(cfqq); |
1da177e4 | 907 | |
22e2c507 JA |
908 | crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); |
909 | rq = crq->request; | |
910 | if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { | |
3b18152c | 911 | cfq_mark_cfqq_fifo_expire(cfqq); |
22e2c507 JA |
912 | return crq; |
913 | } | |
1da177e4 LT |
914 | } |
915 | ||
916 | return NULL; | |
917 | } | |
918 | ||
919 | /* | |
3b18152c JA |
920 | * Scale schedule slice based on io priority. Use the sync time slice only |
921 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
922 | * io only, should not get full sync slice length. | |
1da177e4 | 923 | */ |
22e2c507 JA |
924 | static inline int |
925 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
926 | { | |
927 | const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; | |
928 | ||
929 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); | |
930 | ||
931 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); | |
932 | } | |
933 | ||
1da177e4 | 934 | static inline void |
22e2c507 | 935 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 936 | { |
22e2c507 JA |
937 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
938 | } | |
1da177e4 | 939 | |
22e2c507 JA |
940 | static inline int |
941 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
942 | { | |
943 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 944 | |
22e2c507 | 945 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 946 | |
22e2c507 | 947 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
948 | } |
949 | ||
22e2c507 JA |
950 | /* |
951 | * get next queue for service | |
952 | */ | |
1b5ed5e1 | 953 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 954 | { |
22e2c507 | 955 | unsigned long now = jiffies; |
1da177e4 | 956 | struct cfq_queue *cfqq; |
1da177e4 | 957 | |
22e2c507 JA |
958 | cfqq = cfqd->active_queue; |
959 | if (!cfqq) | |
960 | goto new_queue; | |
1da177e4 | 961 | |
22e2c507 JA |
962 | /* |
963 | * slice has expired | |
964 | */ | |
3b18152c JA |
965 | if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) |
966 | goto expire; | |
1da177e4 | 967 | |
22e2c507 JA |
968 | /* |
969 | * if queue has requests, dispatch one. if not, check if | |
970 | * enough slice is left to wait for one | |
971 | */ | |
dd67d051 | 972 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 | 973 | goto keep_queue; |
caaa5f9f JA |
974 | else if (cfq_cfqq_dispatched(cfqq)) { |
975 | cfqq = NULL; | |
976 | goto keep_queue; | |
977 | } else if (cfq_cfqq_class_sync(cfqq)) { | |
22e2c507 JA |
978 | if (cfq_arm_slice_timer(cfqd, cfqq)) |
979 | return NULL; | |
980 | } | |
981 | ||
3b18152c | 982 | expire: |
22e2c507 | 983 | cfq_slice_expired(cfqd, 0); |
3b18152c JA |
984 | new_queue: |
985 | cfqq = cfq_set_active_queue(cfqd); | |
22e2c507 | 986 | keep_queue: |
3b18152c | 987 | return cfqq; |
22e2c507 JA |
988 | } |
989 | ||
990 | static int | |
991 | __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
992 | int max_dispatch) | |
993 | { | |
994 | int dispatched = 0; | |
995 | ||
dd67d051 | 996 | BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); |
22e2c507 JA |
997 | |
998 | do { | |
999 | struct cfq_rq *crq; | |
1da177e4 LT |
1000 | |
1001 | /* | |
22e2c507 | 1002 | * follow expired path, else get first next available |
1da177e4 | 1003 | */ |
22e2c507 JA |
1004 | if ((crq = cfq_check_fifo(cfqq)) == NULL) |
1005 | crq = cfqq->next_crq; | |
1006 | ||
1007 | /* | |
1008 | * finally, insert request into driver dispatch list | |
1009 | */ | |
b4878f24 | 1010 | cfq_dispatch_insert(cfqd->queue, crq); |
1da177e4 | 1011 | |
22e2c507 JA |
1012 | cfqd->dispatch_slice++; |
1013 | dispatched++; | |
1da177e4 | 1014 | |
22e2c507 JA |
1015 | if (!cfqd->active_cic) { |
1016 | atomic_inc(&crq->io_context->ioc->refcount); | |
1017 | cfqd->active_cic = crq->io_context; | |
1018 | } | |
1da177e4 | 1019 | |
dd67d051 | 1020 | if (RB_EMPTY_ROOT(&cfqq->sort_list)) |
22e2c507 JA |
1021 | break; |
1022 | ||
1023 | } while (dispatched < max_dispatch); | |
1024 | ||
1025 | /* | |
caaa5f9f | 1026 | * if slice end isn't set yet, set it. |
22e2c507 JA |
1027 | */ |
1028 | if (!cfqq->slice_end) | |
1029 | cfq_set_prio_slice(cfqd, cfqq); | |
1030 | ||
1031 | /* | |
1032 | * expire an async queue immediately if it has used up its slice. idle | |
1033 | * queue always expire after 1 dispatch round. | |
1034 | */ | |
1035 | if ((!cfq_cfqq_sync(cfqq) && | |
1036 | cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
caaa5f9f JA |
1037 | cfq_class_idle(cfqq) || |
1038 | !cfq_cfqq_idle_window(cfqq)) | |
22e2c507 JA |
1039 | cfq_slice_expired(cfqd, 0); |
1040 | ||
1041 | return dispatched; | |
1042 | } | |
1043 | ||
1b5ed5e1 TH |
1044 | static int |
1045 | cfq_forced_dispatch_cfqqs(struct list_head *list) | |
1046 | { | |
1b5ed5e1 TH |
1047 | struct cfq_queue *cfqq, *next; |
1048 | struct cfq_rq *crq; | |
caaa5f9f | 1049 | int dispatched; |
1b5ed5e1 | 1050 | |
caaa5f9f | 1051 | dispatched = 0; |
1b5ed5e1 TH |
1052 | list_for_each_entry_safe(cfqq, next, list, cfq_list) { |
1053 | while ((crq = cfqq->next_crq)) { | |
1054 | cfq_dispatch_insert(cfqq->cfqd->queue, crq); | |
1055 | dispatched++; | |
1056 | } | |
1057 | BUG_ON(!list_empty(&cfqq->fifo)); | |
1058 | } | |
caaa5f9f | 1059 | |
1b5ed5e1 TH |
1060 | return dispatched; |
1061 | } | |
1062 | ||
1063 | static int | |
1064 | cfq_forced_dispatch(struct cfq_data *cfqd) | |
1065 | { | |
1066 | int i, dispatched = 0; | |
1067 | ||
1068 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
1069 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]); | |
1070 | ||
1071 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr); | |
1072 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr); | |
1073 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr); | |
1074 | ||
1075 | cfq_slice_expired(cfqd, 0); | |
1076 | ||
1077 | BUG_ON(cfqd->busy_queues); | |
1078 | ||
1079 | return dispatched; | |
1080 | } | |
1081 | ||
22e2c507 | 1082 | static int |
b4878f24 | 1083 | cfq_dispatch_requests(request_queue_t *q, int force) |
22e2c507 JA |
1084 | { |
1085 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
caaa5f9f JA |
1086 | struct cfq_queue *cfqq, *prev_cfqq; |
1087 | int dispatched; | |
22e2c507 JA |
1088 | |
1089 | if (!cfqd->busy_queues) | |
1090 | return 0; | |
1091 | ||
1b5ed5e1 TH |
1092 | if (unlikely(force)) |
1093 | return cfq_forced_dispatch(cfqd); | |
1094 | ||
caaa5f9f JA |
1095 | dispatched = 0; |
1096 | prev_cfqq = NULL; | |
1097 | while ((cfqq = cfq_select_queue(cfqd)) != NULL) { | |
b4878f24 JA |
1098 | int max_dispatch; |
1099 | ||
caaa5f9f JA |
1100 | /* |
1101 | * Don't repeat dispatch from the previous queue. | |
1102 | */ | |
1103 | if (prev_cfqq == cfqq) | |
1104 | break; | |
1105 | ||
3b18152c JA |
1106 | cfq_clear_cfqq_must_dispatch(cfqq); |
1107 | cfq_clear_cfqq_wait_request(cfqq); | |
22e2c507 JA |
1108 | del_timer(&cfqd->idle_slice_timer); |
1109 | ||
1b5ed5e1 TH |
1110 | max_dispatch = cfqd->cfq_quantum; |
1111 | if (cfq_class_idle(cfqq)) | |
1112 | max_dispatch = 1; | |
1da177e4 | 1113 | |
caaa5f9f JA |
1114 | dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
1115 | ||
1116 | /* | |
1117 | * If the dispatch cfqq has idling enabled and is still | |
1118 | * the active queue, break out. | |
1119 | */ | |
1120 | if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue) | |
1121 | break; | |
1122 | ||
1123 | prev_cfqq = cfqq; | |
1da177e4 LT |
1124 | } |
1125 | ||
caaa5f9f | 1126 | return dispatched; |
1da177e4 LT |
1127 | } |
1128 | ||
1da177e4 LT |
1129 | /* |
1130 | * task holds one reference to the queue, dropped when task exits. each crq | |
1131 | * in-flight on this queue also holds a reference, dropped when crq is freed. | |
1132 | * | |
1133 | * queue lock must be held here. | |
1134 | */ | |
1135 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
1136 | { | |
22e2c507 JA |
1137 | struct cfq_data *cfqd = cfqq->cfqd; |
1138 | ||
1139 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
1140 | |
1141 | if (!atomic_dec_and_test(&cfqq->ref)) | |
1142 | return; | |
1143 | ||
1144 | BUG_ON(rb_first(&cfqq->sort_list)); | |
22e2c507 | 1145 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3b18152c | 1146 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 1147 | |
7b14e3b5 | 1148 | if (unlikely(cfqd->active_queue == cfqq)) |
3b18152c | 1149 | __cfq_slice_expired(cfqd, cfqq, 0); |
22e2c507 | 1150 | |
1da177e4 LT |
1151 | /* |
1152 | * it's on the empty list and still hashed | |
1153 | */ | |
1154 | list_del(&cfqq->cfq_list); | |
1155 | hlist_del(&cfqq->cfq_hash); | |
1156 | kmem_cache_free(cfq_pool, cfqq); | |
1157 | } | |
1158 | ||
1159 | static inline struct cfq_queue * | |
3b18152c JA |
1160 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, |
1161 | const int hashval) | |
1da177e4 LT |
1162 | { |
1163 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; | |
206dc69b JA |
1164 | struct hlist_node *entry; |
1165 | struct cfq_queue *__cfqq; | |
1da177e4 | 1166 | |
206dc69b | 1167 | hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) { |
b0a6916b | 1168 | const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio); |
1da177e4 | 1169 | |
206dc69b | 1170 | if (__cfqq->key == key && (__p == prio || !prio)) |
1da177e4 LT |
1171 | return __cfqq; |
1172 | } | |
1173 | ||
1174 | return NULL; | |
1175 | } | |
1176 | ||
1177 | static struct cfq_queue * | |
3b18152c | 1178 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) |
1da177e4 | 1179 | { |
3b18152c | 1180 | return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); |
1da177e4 LT |
1181 | } |
1182 | ||
e2d74ac0 | 1183 | static void cfq_free_io_context(struct io_context *ioc) |
1da177e4 | 1184 | { |
22e2c507 | 1185 | struct cfq_io_context *__cic; |
e2d74ac0 JA |
1186 | struct rb_node *n; |
1187 | int freed = 0; | |
1da177e4 | 1188 | |
e2d74ac0 JA |
1189 | while ((n = rb_first(&ioc->cic_root)) != NULL) { |
1190 | __cic = rb_entry(n, struct cfq_io_context, rb_node); | |
1191 | rb_erase(&__cic->rb_node, &ioc->cic_root); | |
22e2c507 | 1192 | kmem_cache_free(cfq_ioc_pool, __cic); |
334e94de | 1193 | freed++; |
1da177e4 LT |
1194 | } |
1195 | ||
334e94de AV |
1196 | if (atomic_sub_and_test(freed, &ioc_count) && ioc_gone) |
1197 | complete(ioc_gone); | |
1da177e4 LT |
1198 | } |
1199 | ||
e17a9489 AV |
1200 | static void cfq_trim(struct io_context *ioc) |
1201 | { | |
1202 | ioc->set_ioprio = NULL; | |
e2d74ac0 | 1203 | cfq_free_io_context(ioc); |
e17a9489 AV |
1204 | } |
1205 | ||
22e2c507 JA |
1206 | /* |
1207 | * Called with interrupts disabled | |
1208 | */ | |
1209 | static void cfq_exit_single_io_context(struct cfq_io_context *cic) | |
1da177e4 | 1210 | { |
478a82b0 | 1211 | struct cfq_data *cfqd = cic->key; |
d9ff4187 AV |
1212 | request_queue_t *q; |
1213 | ||
1214 | if (!cfqd) | |
1215 | return; | |
1216 | ||
1217 | q = cfqd->queue; | |
22e2c507 JA |
1218 | |
1219 | WARN_ON(!irqs_disabled()); | |
1220 | ||
1221 | spin_lock(q->queue_lock); | |
1222 | ||
12a05732 AV |
1223 | if (cic->cfqq[ASYNC]) { |
1224 | if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue)) | |
1225 | __cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0); | |
1226 | cfq_put_queue(cic->cfqq[ASYNC]); | |
1227 | cic->cfqq[ASYNC] = NULL; | |
1228 | } | |
1229 | ||
1230 | if (cic->cfqq[SYNC]) { | |
1231 | if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue)) | |
1232 | __cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0); | |
1233 | cfq_put_queue(cic->cfqq[SYNC]); | |
1234 | cic->cfqq[SYNC] = NULL; | |
1235 | } | |
22e2c507 | 1236 | |
478a82b0 | 1237 | cic->key = NULL; |
d9ff4187 | 1238 | list_del_init(&cic->queue_list); |
22e2c507 | 1239 | spin_unlock(q->queue_lock); |
1da177e4 LT |
1240 | } |
1241 | ||
e2d74ac0 | 1242 | static void cfq_exit_io_context(struct io_context *ioc) |
1da177e4 | 1243 | { |
22e2c507 | 1244 | struct cfq_io_context *__cic; |
1da177e4 | 1245 | unsigned long flags; |
e2d74ac0 | 1246 | struct rb_node *n; |
22e2c507 | 1247 | |
1da177e4 LT |
1248 | /* |
1249 | * put the reference this task is holding to the various queues | |
1250 | */ | |
3793c65c | 1251 | spin_lock_irqsave(&cfq_exit_lock, flags); |
e2d74ac0 JA |
1252 | |
1253 | n = rb_first(&ioc->cic_root); | |
1254 | while (n != NULL) { | |
1255 | __cic = rb_entry(n, struct cfq_io_context, rb_node); | |
1256 | ||
22e2c507 | 1257 | cfq_exit_single_io_context(__cic); |
e2d74ac0 | 1258 | n = rb_next(n); |
1da177e4 LT |
1259 | } |
1260 | ||
3793c65c | 1261 | spin_unlock_irqrestore(&cfq_exit_lock, flags); |
1da177e4 LT |
1262 | } |
1263 | ||
22e2c507 | 1264 | static struct cfq_io_context * |
8267e268 | 1265 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1266 | { |
22e2c507 | 1267 | struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); |
1da177e4 LT |
1268 | |
1269 | if (cic) { | |
553698f9 | 1270 | memset(cic, 0, sizeof(*cic)); |
22e2c507 | 1271 | cic->last_end_request = jiffies; |
553698f9 | 1272 | INIT_LIST_HEAD(&cic->queue_list); |
22e2c507 JA |
1273 | cic->dtor = cfq_free_io_context; |
1274 | cic->exit = cfq_exit_io_context; | |
334e94de | 1275 | atomic_inc(&ioc_count); |
1da177e4 LT |
1276 | } |
1277 | ||
1278 | return cic; | |
1279 | } | |
1280 | ||
22e2c507 JA |
1281 | static void cfq_init_prio_data(struct cfq_queue *cfqq) |
1282 | { | |
1283 | struct task_struct *tsk = current; | |
1284 | int ioprio_class; | |
1285 | ||
3b18152c | 1286 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
1287 | return; |
1288 | ||
1289 | ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); | |
1290 | switch (ioprio_class) { | |
1291 | default: | |
1292 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
1293 | case IOPRIO_CLASS_NONE: | |
1294 | /* | |
1295 | * no prio set, place us in the middle of the BE classes | |
1296 | */ | |
1297 | cfqq->ioprio = task_nice_ioprio(tsk); | |
1298 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1299 | break; | |
1300 | case IOPRIO_CLASS_RT: | |
1301 | cfqq->ioprio = task_ioprio(tsk); | |
1302 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
1303 | break; | |
1304 | case IOPRIO_CLASS_BE: | |
1305 | cfqq->ioprio = task_ioprio(tsk); | |
1306 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1307 | break; | |
1308 | case IOPRIO_CLASS_IDLE: | |
1309 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
1310 | cfqq->ioprio = 7; | |
3b18152c | 1311 | cfq_clear_cfqq_idle_window(cfqq); |
22e2c507 JA |
1312 | break; |
1313 | } | |
1314 | ||
1315 | /* | |
1316 | * keep track of original prio settings in case we have to temporarily | |
1317 | * elevate the priority of this queue | |
1318 | */ | |
1319 | cfqq->org_ioprio = cfqq->ioprio; | |
1320 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
1321 | ||
3b18152c | 1322 | if (cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1323 | cfq_resort_rr_list(cfqq, 0); |
1324 | ||
3b18152c | 1325 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
1326 | } |
1327 | ||
478a82b0 | 1328 | static inline void changed_ioprio(struct cfq_io_context *cic) |
22e2c507 | 1329 | { |
478a82b0 AV |
1330 | struct cfq_data *cfqd = cic->key; |
1331 | struct cfq_queue *cfqq; | |
35e6077c | 1332 | |
caaa5f9f JA |
1333 | if (unlikely(!cfqd)) |
1334 | return; | |
1335 | ||
1336 | spin_lock(cfqd->queue->queue_lock); | |
1337 | ||
1338 | cfqq = cic->cfqq[ASYNC]; | |
1339 | if (cfqq) { | |
1340 | struct cfq_queue *new_cfqq; | |
1341 | new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task, | |
1342 | GFP_ATOMIC); | |
1343 | if (new_cfqq) { | |
1344 | cic->cfqq[ASYNC] = new_cfqq; | |
1345 | cfq_put_queue(cfqq); | |
1346 | } | |
22e2c507 | 1347 | } |
caaa5f9f JA |
1348 | |
1349 | cfqq = cic->cfqq[SYNC]; | |
1350 | if (cfqq) | |
1351 | cfq_mark_cfqq_prio_changed(cfqq); | |
1352 | ||
1353 | spin_unlock(cfqd->queue->queue_lock); | |
22e2c507 JA |
1354 | } |
1355 | ||
1356 | /* | |
1357 | * callback from sys_ioprio_set, irqs are disabled | |
1358 | */ | |
1359 | static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) | |
1360 | { | |
a6a0763a | 1361 | struct cfq_io_context *cic; |
e2d74ac0 | 1362 | struct rb_node *n; |
a6a0763a | 1363 | |
3793c65c | 1364 | spin_lock(&cfq_exit_lock); |
a6a0763a | 1365 | |
e2d74ac0 JA |
1366 | n = rb_first(&ioc->cic_root); |
1367 | while (n != NULL) { | |
1368 | cic = rb_entry(n, struct cfq_io_context, rb_node); | |
3793c65c | 1369 | |
478a82b0 | 1370 | changed_ioprio(cic); |
e2d74ac0 JA |
1371 | n = rb_next(n); |
1372 | } | |
22e2c507 | 1373 | |
3793c65c | 1374 | spin_unlock(&cfq_exit_lock); |
a6a0763a | 1375 | |
22e2c507 JA |
1376 | return 0; |
1377 | } | |
1378 | ||
1379 | static struct cfq_queue * | |
6f325a13 | 1380 | cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, |
8267e268 | 1381 | gfp_t gfp_mask) |
22e2c507 JA |
1382 | { |
1383 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); | |
1384 | struct cfq_queue *cfqq, *new_cfqq = NULL; | |
6f325a13 | 1385 | unsigned short ioprio; |
22e2c507 JA |
1386 | |
1387 | retry: | |
6f325a13 | 1388 | ioprio = tsk->ioprio; |
3b18152c | 1389 | cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); |
22e2c507 JA |
1390 | |
1391 | if (!cfqq) { | |
1392 | if (new_cfqq) { | |
1393 | cfqq = new_cfqq; | |
1394 | new_cfqq = NULL; | |
1395 | } else if (gfp_mask & __GFP_WAIT) { | |
1396 | spin_unlock_irq(cfqd->queue->queue_lock); | |
1397 | new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1398 | spin_lock_irq(cfqd->queue->queue_lock); | |
1399 | goto retry; | |
1400 | } else { | |
1401 | cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1402 | if (!cfqq) | |
1403 | goto out; | |
1404 | } | |
1405 | ||
1406 | memset(cfqq, 0, sizeof(*cfqq)); | |
1407 | ||
1408 | INIT_HLIST_NODE(&cfqq->cfq_hash); | |
1409 | INIT_LIST_HEAD(&cfqq->cfq_list); | |
22e2c507 JA |
1410 | INIT_LIST_HEAD(&cfqq->fifo); |
1411 | ||
1412 | cfqq->key = key; | |
1413 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); | |
1414 | atomic_set(&cfqq->ref, 0); | |
1415 | cfqq->cfqd = cfqd; | |
22e2c507 JA |
1416 | cfqq->service_last = 0; |
1417 | /* | |
1418 | * set ->slice_left to allow preemption for a new process | |
1419 | */ | |
1420 | cfqq->slice_left = 2 * cfqd->cfq_slice_idle; | |
caaa5f9f | 1421 | cfq_mark_cfqq_idle_window(cfqq); |
3b18152c JA |
1422 | cfq_mark_cfqq_prio_changed(cfqq); |
1423 | cfq_init_prio_data(cfqq); | |
22e2c507 JA |
1424 | } |
1425 | ||
1426 | if (new_cfqq) | |
1427 | kmem_cache_free(cfq_pool, new_cfqq); | |
1428 | ||
1429 | atomic_inc(&cfqq->ref); | |
1430 | out: | |
1431 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); | |
1432 | return cfqq; | |
1433 | } | |
1434 | ||
dbecf3ab OH |
1435 | static void |
1436 | cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic) | |
1437 | { | |
3793c65c | 1438 | spin_lock(&cfq_exit_lock); |
dbecf3ab | 1439 | rb_erase(&cic->rb_node, &ioc->cic_root); |
3793c65c JA |
1440 | list_del_init(&cic->queue_list); |
1441 | spin_unlock(&cfq_exit_lock); | |
dbecf3ab OH |
1442 | kmem_cache_free(cfq_ioc_pool, cic); |
1443 | atomic_dec(&ioc_count); | |
1444 | } | |
1445 | ||
e2d74ac0 JA |
1446 | static struct cfq_io_context * |
1447 | cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc) | |
1448 | { | |
dbecf3ab | 1449 | struct rb_node *n; |
e2d74ac0 | 1450 | struct cfq_io_context *cic; |
be3b0753 | 1451 | void *k, *key = cfqd; |
e2d74ac0 | 1452 | |
dbecf3ab OH |
1453 | restart: |
1454 | n = ioc->cic_root.rb_node; | |
e2d74ac0 JA |
1455 | while (n) { |
1456 | cic = rb_entry(n, struct cfq_io_context, rb_node); | |
be3b0753 OH |
1457 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
1458 | k = cic->key; | |
1459 | if (unlikely(!k)) { | |
dbecf3ab OH |
1460 | cfq_drop_dead_cic(ioc, cic); |
1461 | goto restart; | |
1462 | } | |
e2d74ac0 | 1463 | |
be3b0753 | 1464 | if (key < k) |
e2d74ac0 | 1465 | n = n->rb_left; |
be3b0753 | 1466 | else if (key > k) |
e2d74ac0 JA |
1467 | n = n->rb_right; |
1468 | else | |
1469 | return cic; | |
1470 | } | |
1471 | ||
1472 | return NULL; | |
1473 | } | |
1474 | ||
1475 | static inline void | |
1476 | cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, | |
1477 | struct cfq_io_context *cic) | |
1478 | { | |
dbecf3ab OH |
1479 | struct rb_node **p; |
1480 | struct rb_node *parent; | |
e2d74ac0 | 1481 | struct cfq_io_context *__cic; |
be3b0753 | 1482 | void *k; |
e2d74ac0 | 1483 | |
e2d74ac0 JA |
1484 | cic->ioc = ioc; |
1485 | cic->key = cfqd; | |
1486 | ||
1487 | ioc->set_ioprio = cfq_ioc_set_ioprio; | |
dbecf3ab OH |
1488 | restart: |
1489 | parent = NULL; | |
1490 | p = &ioc->cic_root.rb_node; | |
e2d74ac0 JA |
1491 | while (*p) { |
1492 | parent = *p; | |
1493 | __cic = rb_entry(parent, struct cfq_io_context, rb_node); | |
be3b0753 OH |
1494 | /* ->key must be copied to avoid race with cfq_exit_queue() */ |
1495 | k = __cic->key; | |
1496 | if (unlikely(!k)) { | |
be33c3a6 | 1497 | cfq_drop_dead_cic(ioc, __cic); |
dbecf3ab OH |
1498 | goto restart; |
1499 | } | |
e2d74ac0 | 1500 | |
be3b0753 | 1501 | if (cic->key < k) |
e2d74ac0 | 1502 | p = &(*p)->rb_left; |
be3b0753 | 1503 | else if (cic->key > k) |
e2d74ac0 JA |
1504 | p = &(*p)->rb_right; |
1505 | else | |
1506 | BUG(); | |
1507 | } | |
1508 | ||
3793c65c | 1509 | spin_lock(&cfq_exit_lock); |
e2d74ac0 JA |
1510 | rb_link_node(&cic->rb_node, parent, p); |
1511 | rb_insert_color(&cic->rb_node, &ioc->cic_root); | |
1512 | list_add(&cic->queue_list, &cfqd->cic_list); | |
3793c65c | 1513 | spin_unlock(&cfq_exit_lock); |
e2d74ac0 JA |
1514 | } |
1515 | ||
1da177e4 LT |
1516 | /* |
1517 | * Setup general io context and cfq io context. There can be several cfq | |
1518 | * io contexts per general io context, if this process is doing io to more | |
e2d74ac0 | 1519 | * than one device managed by cfq. |
1da177e4 LT |
1520 | */ |
1521 | static struct cfq_io_context * | |
e2d74ac0 | 1522 | cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1523 | { |
22e2c507 | 1524 | struct io_context *ioc = NULL; |
1da177e4 | 1525 | struct cfq_io_context *cic; |
1da177e4 | 1526 | |
22e2c507 | 1527 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 1528 | |
22e2c507 | 1529 | ioc = get_io_context(gfp_mask); |
1da177e4 LT |
1530 | if (!ioc) |
1531 | return NULL; | |
1532 | ||
e2d74ac0 JA |
1533 | cic = cfq_cic_rb_lookup(cfqd, ioc); |
1534 | if (cic) | |
1535 | goto out; | |
1da177e4 | 1536 | |
e2d74ac0 JA |
1537 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1538 | if (cic == NULL) | |
1539 | goto err; | |
1da177e4 | 1540 | |
e2d74ac0 | 1541 | cfq_cic_link(cfqd, ioc, cic); |
1da177e4 | 1542 | out: |
1da177e4 LT |
1543 | return cic; |
1544 | err: | |
1545 | put_io_context(ioc); | |
1546 | return NULL; | |
1547 | } | |
1548 | ||
22e2c507 JA |
1549 | static void |
1550 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 1551 | { |
22e2c507 | 1552 | unsigned long elapsed, ttime; |
1da177e4 | 1553 | |
22e2c507 JA |
1554 | /* |
1555 | * if this context already has stuff queued, thinktime is from | |
1556 | * last queue not last end | |
1557 | */ | |
1558 | #if 0 | |
1559 | if (time_after(cic->last_end_request, cic->last_queue)) | |
1560 | elapsed = jiffies - cic->last_end_request; | |
1561 | else | |
1562 | elapsed = jiffies - cic->last_queue; | |
1563 | #else | |
1564 | elapsed = jiffies - cic->last_end_request; | |
1565 | #endif | |
1da177e4 | 1566 | |
22e2c507 | 1567 | ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
db3b5848 | 1568 | |
22e2c507 JA |
1569 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
1570 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
1571 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
1572 | } | |
1da177e4 | 1573 | |
206dc69b JA |
1574 | static void |
1575 | cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic, | |
1576 | struct cfq_rq *crq) | |
1577 | { | |
1578 | sector_t sdist; | |
1579 | u64 total; | |
1580 | ||
1581 | if (cic->last_request_pos < crq->request->sector) | |
1582 | sdist = crq->request->sector - cic->last_request_pos; | |
1583 | else | |
1584 | sdist = cic->last_request_pos - crq->request->sector; | |
1585 | ||
1586 | /* | |
1587 | * Don't allow the seek distance to get too large from the | |
1588 | * odd fragment, pagein, etc | |
1589 | */ | |
1590 | if (cic->seek_samples <= 60) /* second&third seek */ | |
1591 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024); | |
1592 | else | |
1593 | sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64); | |
1594 | ||
1595 | cic->seek_samples = (7*cic->seek_samples + 256) / 8; | |
1596 | cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8; | |
1597 | total = cic->seek_total + (cic->seek_samples/2); | |
1598 | do_div(total, cic->seek_samples); | |
1599 | cic->seek_mean = (sector_t)total; | |
1600 | } | |
1da177e4 | 1601 | |
22e2c507 JA |
1602 | /* |
1603 | * Disable idle window if the process thinks too long or seeks so much that | |
1604 | * it doesn't matter | |
1605 | */ | |
1606 | static void | |
1607 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1608 | struct cfq_io_context *cic) | |
1609 | { | |
3b18152c | 1610 | int enable_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 1611 | |
caaa5f9f JA |
1612 | if (!cic->ioc->task || !cfqd->cfq_slice_idle || |
1613 | (cfqd->hw_tag && CIC_SEEKY(cic))) | |
22e2c507 JA |
1614 | enable_idle = 0; |
1615 | else if (sample_valid(cic->ttime_samples)) { | |
1616 | if (cic->ttime_mean > cfqd->cfq_slice_idle) | |
1617 | enable_idle = 0; | |
1618 | else | |
1619 | enable_idle = 1; | |
1da177e4 LT |
1620 | } |
1621 | ||
3b18152c JA |
1622 | if (enable_idle) |
1623 | cfq_mark_cfqq_idle_window(cfqq); | |
1624 | else | |
1625 | cfq_clear_cfqq_idle_window(cfqq); | |
22e2c507 | 1626 | } |
1da177e4 | 1627 | |
22e2c507 JA |
1628 | |
1629 | /* | |
1630 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
1631 | * no or if we aren't sure, a 1 will cause a preempt. | |
1632 | */ | |
1633 | static int | |
1634 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, | |
1635 | struct cfq_rq *crq) | |
1636 | { | |
1637 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1638 | ||
1639 | if (cfq_class_idle(new_cfqq)) | |
1640 | return 0; | |
1641 | ||
1642 | if (!cfqq) | |
caaa5f9f | 1643 | return 0; |
22e2c507 JA |
1644 | |
1645 | if (cfq_class_idle(cfqq)) | |
1646 | return 1; | |
3b18152c | 1647 | if (!cfq_cfqq_wait_request(new_cfqq)) |
22e2c507 JA |
1648 | return 0; |
1649 | /* | |
1650 | * if it doesn't have slice left, forget it | |
1651 | */ | |
1652 | if (new_cfqq->slice_left < cfqd->cfq_slice_idle) | |
1653 | return 0; | |
3b18152c | 1654 | if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq)) |
22e2c507 JA |
1655 | return 1; |
1656 | ||
1657 | return 0; | |
1658 | } | |
1659 | ||
1660 | /* | |
1661 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
1662 | * let it have half of its nominal slice. | |
1663 | */ | |
1664 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1665 | { | |
1666 | struct cfq_queue *__cfqq, *next; | |
1667 | ||
1668 | list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) | |
1669 | cfq_resort_rr_list(__cfqq, 1); | |
1670 | ||
1671 | if (!cfqq->slice_left) | |
1672 | cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; | |
1673 | ||
1674 | cfqq->slice_end = cfqq->slice_left + jiffies; | |
caaa5f9f | 1675 | cfq_slice_expired(cfqd, 1); |
22e2c507 JA |
1676 | __cfq_set_active_queue(cfqd, cfqq); |
1677 | } | |
1678 | ||
1679 | /* | |
1680 | * should really be a ll_rw_blk.c helper | |
1681 | */ | |
1682 | static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1683 | { | |
1684 | request_queue_t *q = cfqd->queue; | |
1685 | ||
1686 | if (!blk_queue_plugged(q)) | |
1687 | q->request_fn(q); | |
1688 | else | |
1689 | __generic_unplug_device(q); | |
1690 | } | |
1691 | ||
1692 | /* | |
1693 | * Called when a new fs request (crq) is added (to cfqq). Check if there's | |
1694 | * something we should do about it | |
1695 | */ | |
1696 | static void | |
1697 | cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1698 | struct cfq_rq *crq) | |
1699 | { | |
fd61af03 | 1700 | struct cfq_io_context *cic = crq->io_context; |
12e9fddd | 1701 | |
9c2c38a1 JA |
1702 | /* |
1703 | * we never wait for an async request and we don't allow preemption | |
1704 | * of an async request. so just return early | |
1705 | */ | |
12e9fddd JA |
1706 | if (!cfq_crq_is_sync(crq)) { |
1707 | /* | |
1708 | * sync process issued an async request, if it's waiting | |
1709 | * then expire it and kick rq handling. | |
1710 | */ | |
1711 | if (cic == cfqd->active_cic && | |
1712 | del_timer(&cfqd->idle_slice_timer)) { | |
1713 | cfq_slice_expired(cfqd, 0); | |
1714 | cfq_start_queueing(cfqd, cfqq); | |
1715 | } | |
9c2c38a1 | 1716 | return; |
12e9fddd | 1717 | } |
22e2c507 | 1718 | |
9c2c38a1 | 1719 | cfq_update_io_thinktime(cfqd, cic); |
206dc69b | 1720 | cfq_update_io_seektime(cfqd, cic, crq); |
9c2c38a1 JA |
1721 | cfq_update_idle_window(cfqd, cfqq, cic); |
1722 | ||
1723 | cic->last_queue = jiffies; | |
206dc69b | 1724 | cic->last_request_pos = crq->request->sector + crq->request->nr_sectors; |
22e2c507 JA |
1725 | |
1726 | if (cfqq == cfqd->active_queue) { | |
1727 | /* | |
1728 | * if we are waiting for a request for this queue, let it rip | |
1729 | * immediately and flag that we must not expire this queue | |
1730 | * just now | |
1731 | */ | |
3b18152c JA |
1732 | if (cfq_cfqq_wait_request(cfqq)) { |
1733 | cfq_mark_cfqq_must_dispatch(cfqq); | |
22e2c507 JA |
1734 | del_timer(&cfqd->idle_slice_timer); |
1735 | cfq_start_queueing(cfqd, cfqq); | |
1736 | } | |
1737 | } else if (cfq_should_preempt(cfqd, cfqq, crq)) { | |
1738 | /* | |
1739 | * not the active queue - expire current slice if it is | |
1740 | * idle and has expired it's mean thinktime or this new queue | |
1741 | * has some old slice time left and is of higher priority | |
1742 | */ | |
1743 | cfq_preempt_queue(cfqd, cfqq); | |
3b18152c | 1744 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
1745 | cfq_start_queueing(cfqd, cfqq); |
1746 | } | |
1da177e4 LT |
1747 | } |
1748 | ||
b4878f24 | 1749 | static void cfq_insert_request(request_queue_t *q, struct request *rq) |
1da177e4 | 1750 | { |
b4878f24 | 1751 | struct cfq_data *cfqd = q->elevator->elevator_data; |
22e2c507 JA |
1752 | struct cfq_rq *crq = RQ_DATA(rq); |
1753 | struct cfq_queue *cfqq = crq->cfq_queue; | |
1754 | ||
1755 | cfq_init_prio_data(cfqq); | |
1da177e4 LT |
1756 | |
1757 | cfq_add_crq_rb(crq); | |
1da177e4 | 1758 | |
22e2c507 JA |
1759 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
1760 | ||
22e2c507 | 1761 | cfq_crq_enqueued(cfqd, cfqq, crq); |
1da177e4 LT |
1762 | } |
1763 | ||
1da177e4 LT |
1764 | static void cfq_completed_request(request_queue_t *q, struct request *rq) |
1765 | { | |
1766 | struct cfq_rq *crq = RQ_DATA(rq); | |
b4878f24 JA |
1767 | struct cfq_queue *cfqq = crq->cfq_queue; |
1768 | struct cfq_data *cfqd = cfqq->cfqd; | |
1769 | const int sync = cfq_crq_is_sync(crq); | |
1770 | unsigned long now; | |
1da177e4 | 1771 | |
b4878f24 | 1772 | now = jiffies; |
1da177e4 | 1773 | |
b4878f24 JA |
1774 | WARN_ON(!cfqd->rq_in_driver); |
1775 | WARN_ON(!cfqq->on_dispatch[sync]); | |
1776 | cfqd->rq_in_driver--; | |
1777 | cfqq->on_dispatch[sync]--; | |
1da177e4 | 1778 | |
b4878f24 JA |
1779 | if (!cfq_class_idle(cfqq)) |
1780 | cfqd->last_end_request = now; | |
3b18152c | 1781 | |
b4878f24 JA |
1782 | if (!cfq_cfqq_dispatched(cfqq)) { |
1783 | if (cfq_cfqq_on_rr(cfqq)) { | |
1784 | cfqq->service_last = now; | |
1785 | cfq_resort_rr_list(cfqq, 0); | |
1786 | } | |
1da177e4 LT |
1787 | } |
1788 | ||
caaa5f9f | 1789 | if (sync) |
b4878f24 | 1790 | crq->io_context->last_end_request = now; |
caaa5f9f JA |
1791 | |
1792 | /* | |
1793 | * If this is the active queue, check if it needs to be expired, | |
1794 | * or if we want to idle in case it has no pending requests. | |
1795 | */ | |
1796 | if (cfqd->active_queue == cfqq) { | |
1797 | if (time_after(now, cfqq->slice_end)) | |
1798 | cfq_slice_expired(cfqd, 0); | |
dd67d051 | 1799 | else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
caaa5f9f JA |
1800 | if (!cfq_arm_slice_timer(cfqd, cfqq)) |
1801 | cfq_schedule_dispatch(cfqd); | |
1802 | } | |
1803 | } | |
1da177e4 LT |
1804 | } |
1805 | ||
1806 | static struct request * | |
1807 | cfq_former_request(request_queue_t *q, struct request *rq) | |
1808 | { | |
1809 | struct cfq_rq *crq = RQ_DATA(rq); | |
1810 | struct rb_node *rbprev = rb_prev(&crq->rb_node); | |
1811 | ||
1812 | if (rbprev) | |
1813 | return rb_entry_crq(rbprev)->request; | |
1814 | ||
1815 | return NULL; | |
1816 | } | |
1817 | ||
1818 | static struct request * | |
1819 | cfq_latter_request(request_queue_t *q, struct request *rq) | |
1820 | { | |
1821 | struct cfq_rq *crq = RQ_DATA(rq); | |
1822 | struct rb_node *rbnext = rb_next(&crq->rb_node); | |
1823 | ||
1824 | if (rbnext) | |
1825 | return rb_entry_crq(rbnext)->request; | |
1826 | ||
1827 | return NULL; | |
1828 | } | |
1829 | ||
22e2c507 JA |
1830 | /* |
1831 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
1832 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
1833 | */ | |
1834 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 1835 | { |
22e2c507 JA |
1836 | const int ioprio_class = cfqq->ioprio_class; |
1837 | const int ioprio = cfqq->ioprio; | |
1da177e4 | 1838 | |
22e2c507 JA |
1839 | if (has_fs_excl()) { |
1840 | /* | |
1841 | * boost idle prio on transactions that would lock out other | |
1842 | * users of the filesystem | |
1843 | */ | |
1844 | if (cfq_class_idle(cfqq)) | |
1845 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1846 | if (cfqq->ioprio > IOPRIO_NORM) | |
1847 | cfqq->ioprio = IOPRIO_NORM; | |
1848 | } else { | |
1849 | /* | |
1850 | * check if we need to unboost the queue | |
1851 | */ | |
1852 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) | |
1853 | cfqq->ioprio_class = cfqq->org_ioprio_class; | |
1854 | if (cfqq->ioprio != cfqq->org_ioprio) | |
1855 | cfqq->ioprio = cfqq->org_ioprio; | |
1856 | } | |
1da177e4 | 1857 | |
22e2c507 JA |
1858 | /* |
1859 | * refile between round-robin lists if we moved the priority class | |
1860 | */ | |
1861 | if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && | |
3b18152c | 1862 | cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1863 | cfq_resort_rr_list(cfqq, 0); |
1864 | } | |
1da177e4 | 1865 | |
22e2c507 JA |
1866 | static inline int |
1867 | __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1868 | struct task_struct *task, int rw) | |
1869 | { | |
3b18152c | 1870 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && |
99f95e52 | 1871 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1872 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1873 | return ELV_MQUEUE_MUST; |
3b18152c | 1874 | } |
1da177e4 | 1875 | |
22e2c507 | 1876 | return ELV_MQUEUE_MAY; |
22e2c507 JA |
1877 | } |
1878 | ||
1879 | static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) | |
1880 | { | |
1881 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1882 | struct task_struct *tsk = current; | |
1883 | struct cfq_queue *cfqq; | |
1884 | ||
1885 | /* | |
1886 | * don't force setup of a queue from here, as a call to may_queue | |
1887 | * does not necessarily imply that a request actually will be queued. | |
1888 | * so just lookup a possibly existing queue, or return 'may queue' | |
1889 | * if that fails | |
1890 | */ | |
3b18152c | 1891 | cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); |
22e2c507 JA |
1892 | if (cfqq) { |
1893 | cfq_init_prio_data(cfqq); | |
1894 | cfq_prio_boost(cfqq); | |
1895 | ||
1896 | return __cfq_may_queue(cfqd, cfqq, tsk, rw); | |
1897 | } | |
1898 | ||
1899 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
1900 | } |
1901 | ||
1902 | static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) | |
1903 | { | |
22e2c507 | 1904 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1da177e4 | 1905 | |
271f18f1 JA |
1906 | if (unlikely(cfqd->rq_starved)) { |
1907 | struct request_list *rl = &q->rq; | |
1908 | ||
22e2c507 JA |
1909 | smp_mb(); |
1910 | if (waitqueue_active(&rl->wait[READ])) | |
1911 | wake_up(&rl->wait[READ]); | |
22e2c507 JA |
1912 | if (waitqueue_active(&rl->wait[WRITE])) |
1913 | wake_up(&rl->wait[WRITE]); | |
1914 | } | |
1da177e4 LT |
1915 | } |
1916 | ||
1917 | /* | |
1918 | * queue lock held here | |
1919 | */ | |
1920 | static void cfq_put_request(request_queue_t *q, struct request *rq) | |
1921 | { | |
1922 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1923 | struct cfq_rq *crq = RQ_DATA(rq); | |
1924 | ||
1925 | if (crq) { | |
1926 | struct cfq_queue *cfqq = crq->cfq_queue; | |
22e2c507 | 1927 | const int rw = rq_data_dir(rq); |
1da177e4 | 1928 | |
22e2c507 JA |
1929 | BUG_ON(!cfqq->allocated[rw]); |
1930 | cfqq->allocated[rw]--; | |
1da177e4 | 1931 | |
22e2c507 | 1932 | put_io_context(crq->io_context->ioc); |
1da177e4 LT |
1933 | |
1934 | mempool_free(crq, cfqd->crq_pool); | |
1935 | rq->elevator_private = NULL; | |
1936 | ||
1da177e4 LT |
1937 | cfq_check_waiters(q, cfqq); |
1938 | cfq_put_queue(cfqq); | |
1939 | } | |
1940 | } | |
1941 | ||
1942 | /* | |
22e2c507 | 1943 | * Allocate cfq data structures associated with this request. |
1da177e4 | 1944 | */ |
22e2c507 JA |
1945 | static int |
1946 | cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, | |
8267e268 | 1947 | gfp_t gfp_mask) |
1da177e4 LT |
1948 | { |
1949 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3b18152c | 1950 | struct task_struct *tsk = current; |
1da177e4 LT |
1951 | struct cfq_io_context *cic; |
1952 | const int rw = rq_data_dir(rq); | |
3b18152c | 1953 | pid_t key = cfq_queue_pid(tsk, rw); |
22e2c507 | 1954 | struct cfq_queue *cfqq; |
1da177e4 LT |
1955 | struct cfq_rq *crq; |
1956 | unsigned long flags; | |
12a05732 | 1957 | int is_sync = key != CFQ_KEY_ASYNC; |
1da177e4 LT |
1958 | |
1959 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
1960 | ||
e2d74ac0 | 1961 | cic = cfq_get_io_context(cfqd, gfp_mask); |
22e2c507 | 1962 | |
1da177e4 LT |
1963 | spin_lock_irqsave(q->queue_lock, flags); |
1964 | ||
22e2c507 JA |
1965 | if (!cic) |
1966 | goto queue_fail; | |
1967 | ||
12a05732 | 1968 | if (!cic->cfqq[is_sync]) { |
6f325a13 | 1969 | cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask); |
22e2c507 JA |
1970 | if (!cfqq) |
1971 | goto queue_fail; | |
1da177e4 | 1972 | |
12a05732 | 1973 | cic->cfqq[is_sync] = cfqq; |
22e2c507 | 1974 | } else |
12a05732 | 1975 | cfqq = cic->cfqq[is_sync]; |
1da177e4 LT |
1976 | |
1977 | cfqq->allocated[rw]++; | |
3b18152c | 1978 | cfq_clear_cfqq_must_alloc(cfqq); |
22e2c507 JA |
1979 | cfqd->rq_starved = 0; |
1980 | atomic_inc(&cfqq->ref); | |
1da177e4 LT |
1981 | spin_unlock_irqrestore(q->queue_lock, flags); |
1982 | ||
1da177e4 LT |
1983 | crq = mempool_alloc(cfqd->crq_pool, gfp_mask); |
1984 | if (crq) { | |
dd67d051 | 1985 | RB_CLEAR_NODE(&crq->rb_node); |
1da177e4 LT |
1986 | crq->rb_key = 0; |
1987 | crq->request = rq; | |
1da177e4 LT |
1988 | crq->cfq_queue = cfqq; |
1989 | crq->io_context = cic; | |
3b18152c | 1990 | |
12a05732 | 1991 | if (is_sync) |
3b18152c JA |
1992 | cfq_mark_crq_is_sync(crq); |
1993 | else | |
1994 | cfq_clear_crq_is_sync(crq); | |
1995 | ||
1da177e4 | 1996 | rq->elevator_private = crq; |
1da177e4 LT |
1997 | return 0; |
1998 | } | |
1999 | ||
1da177e4 LT |
2000 | spin_lock_irqsave(q->queue_lock, flags); |
2001 | cfqq->allocated[rw]--; | |
22e2c507 | 2002 | if (!(cfqq->allocated[0] + cfqq->allocated[1])) |
3b18152c | 2003 | cfq_mark_cfqq_must_alloc(cfqq); |
1da177e4 | 2004 | cfq_put_queue(cfqq); |
22e2c507 JA |
2005 | queue_fail: |
2006 | if (cic) | |
2007 | put_io_context(cic->ioc); | |
2008 | /* | |
2009 | * mark us rq allocation starved. we need to kickstart the process | |
2010 | * ourselves if there are no pending requests that can do it for us. | |
2011 | * that would be an extremely rare OOM situation | |
2012 | */ | |
2013 | cfqd->rq_starved = 1; | |
3b18152c | 2014 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
2015 | spin_unlock_irqrestore(q->queue_lock, flags); |
2016 | return 1; | |
2017 | } | |
2018 | ||
22e2c507 JA |
2019 | static void cfq_kick_queue(void *data) |
2020 | { | |
2021 | request_queue_t *q = data; | |
2022 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2023 | unsigned long flags; | |
2024 | ||
2025 | spin_lock_irqsave(q->queue_lock, flags); | |
2026 | ||
2027 | if (cfqd->rq_starved) { | |
2028 | struct request_list *rl = &q->rq; | |
2029 | ||
2030 | /* | |
2031 | * we aren't guaranteed to get a request after this, but we | |
2032 | * have to be opportunistic | |
2033 | */ | |
2034 | smp_mb(); | |
2035 | if (waitqueue_active(&rl->wait[READ])) | |
2036 | wake_up(&rl->wait[READ]); | |
2037 | if (waitqueue_active(&rl->wait[WRITE])) | |
2038 | wake_up(&rl->wait[WRITE]); | |
2039 | } | |
2040 | ||
2041 | blk_remove_plug(q); | |
2042 | q->request_fn(q); | |
2043 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2044 | } | |
2045 | ||
2046 | /* | |
2047 | * Timer running if the active_queue is currently idling inside its time slice | |
2048 | */ | |
2049 | static void cfq_idle_slice_timer(unsigned long data) | |
2050 | { | |
2051 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2052 | struct cfq_queue *cfqq; | |
2053 | unsigned long flags; | |
2054 | ||
2055 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2056 | ||
2057 | if ((cfqq = cfqd->active_queue) != NULL) { | |
2058 | unsigned long now = jiffies; | |
2059 | ||
2060 | /* | |
2061 | * expired | |
2062 | */ | |
2063 | if (time_after(now, cfqq->slice_end)) | |
2064 | goto expire; | |
2065 | ||
2066 | /* | |
2067 | * only expire and reinvoke request handler, if there are | |
2068 | * other queues with pending requests | |
2069 | */ | |
caaa5f9f | 2070 | if (!cfqd->busy_queues) |
22e2c507 | 2071 | goto out_cont; |
22e2c507 JA |
2072 | |
2073 | /* | |
2074 | * not expired and it has a request pending, let it dispatch | |
2075 | */ | |
dd67d051 | 2076 | if (!RB_EMPTY_ROOT(&cfqq->sort_list)) { |
3b18152c | 2077 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
2078 | goto out_kick; |
2079 | } | |
2080 | } | |
2081 | expire: | |
2082 | cfq_slice_expired(cfqd, 0); | |
2083 | out_kick: | |
3b18152c | 2084 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2085 | out_cont: |
2086 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2087 | } | |
2088 | ||
2089 | /* | |
2090 | * Timer running if an idle class queue is waiting for service | |
2091 | */ | |
2092 | static void cfq_idle_class_timer(unsigned long data) | |
2093 | { | |
2094 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2095 | unsigned long flags, end; | |
2096 | ||
2097 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2098 | ||
2099 | /* | |
2100 | * race with a non-idle queue, reset timer | |
2101 | */ | |
2102 | end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
ae818a38 JA |
2103 | if (!time_after_eq(jiffies, end)) |
2104 | mod_timer(&cfqd->idle_class_timer, end); | |
2105 | else | |
3b18152c | 2106 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2107 | |
2108 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2109 | } | |
2110 | ||
3b18152c JA |
2111 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
2112 | { | |
2113 | del_timer_sync(&cfqd->idle_slice_timer); | |
2114 | del_timer_sync(&cfqd->idle_class_timer); | |
2115 | blk_sync_queue(cfqd->queue); | |
2116 | } | |
22e2c507 | 2117 | |
1da177e4 LT |
2118 | static void cfq_exit_queue(elevator_t *e) |
2119 | { | |
22e2c507 | 2120 | struct cfq_data *cfqd = e->elevator_data; |
d9ff4187 | 2121 | request_queue_t *q = cfqd->queue; |
22e2c507 | 2122 | |
3b18152c | 2123 | cfq_shutdown_timer_wq(cfqd); |
e2d74ac0 | 2124 | |
3793c65c | 2125 | spin_lock(&cfq_exit_lock); |
d9ff4187 | 2126 | spin_lock_irq(q->queue_lock); |
e2d74ac0 | 2127 | |
d9ff4187 AV |
2128 | if (cfqd->active_queue) |
2129 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); | |
e2d74ac0 JA |
2130 | |
2131 | while (!list_empty(&cfqd->cic_list)) { | |
d9ff4187 AV |
2132 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
2133 | struct cfq_io_context, | |
2134 | queue_list); | |
2135 | if (cic->cfqq[ASYNC]) { | |
2136 | cfq_put_queue(cic->cfqq[ASYNC]); | |
2137 | cic->cfqq[ASYNC] = NULL; | |
2138 | } | |
2139 | if (cic->cfqq[SYNC]) { | |
2140 | cfq_put_queue(cic->cfqq[SYNC]); | |
2141 | cic->cfqq[SYNC] = NULL; | |
2142 | } | |
2143 | cic->key = NULL; | |
2144 | list_del_init(&cic->queue_list); | |
2145 | } | |
e2d74ac0 | 2146 | |
d9ff4187 | 2147 | spin_unlock_irq(q->queue_lock); |
3793c65c | 2148 | spin_unlock(&cfq_exit_lock); |
a90d742e AV |
2149 | |
2150 | cfq_shutdown_timer_wq(cfqd); | |
2151 | ||
2152 | mempool_destroy(cfqd->crq_pool); | |
a90d742e AV |
2153 | kfree(cfqd->cfq_hash); |
2154 | kfree(cfqd); | |
1da177e4 LT |
2155 | } |
2156 | ||
bc1c1169 | 2157 | static void *cfq_init_queue(request_queue_t *q, elevator_t *e) |
1da177e4 LT |
2158 | { |
2159 | struct cfq_data *cfqd; | |
2160 | int i; | |
2161 | ||
2162 | cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); | |
2163 | if (!cfqd) | |
bc1c1169 | 2164 | return NULL; |
1da177e4 LT |
2165 | |
2166 | memset(cfqd, 0, sizeof(*cfqd)); | |
22e2c507 JA |
2167 | |
2168 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
2169 | INIT_LIST_HEAD(&cfqd->rr_list[i]); | |
2170 | ||
2171 | INIT_LIST_HEAD(&cfqd->busy_rr); | |
2172 | INIT_LIST_HEAD(&cfqd->cur_rr); | |
2173 | INIT_LIST_HEAD(&cfqd->idle_rr); | |
1da177e4 | 2174 | INIT_LIST_HEAD(&cfqd->empty_list); |
d9ff4187 | 2175 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 | 2176 | |
1da177e4 LT |
2177 | cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); |
2178 | if (!cfqd->cfq_hash) | |
9817064b | 2179 | goto out_crqhash; |
1da177e4 | 2180 | |
93d2341c | 2181 | cfqd->crq_pool = mempool_create_slab_pool(BLKDEV_MIN_RQ, crq_pool); |
1da177e4 LT |
2182 | if (!cfqd->crq_pool) |
2183 | goto out_crqpool; | |
2184 | ||
1da177e4 LT |
2185 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) |
2186 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); | |
2187 | ||
1da177e4 | 2188 | cfqd->queue = q; |
1da177e4 | 2189 | |
22e2c507 JA |
2190 | init_timer(&cfqd->idle_slice_timer); |
2191 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
2192 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
2193 | ||
2194 | init_timer(&cfqd->idle_class_timer); | |
2195 | cfqd->idle_class_timer.function = cfq_idle_class_timer; | |
2196 | cfqd->idle_class_timer.data = (unsigned long) cfqd; | |
2197 | ||
2198 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); | |
2199 | ||
1da177e4 LT |
2200 | cfqd->cfq_queued = cfq_queued; |
2201 | cfqd->cfq_quantum = cfq_quantum; | |
22e2c507 JA |
2202 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
2203 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
2204 | cfqd->cfq_back_max = cfq_back_max; |
2205 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
2206 | cfqd->cfq_slice[0] = cfq_slice_async; |
2207 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
2208 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
2209 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
3b18152c | 2210 | |
bc1c1169 | 2211 | return cfqd; |
1da177e4 LT |
2212 | out_crqpool: |
2213 | kfree(cfqd->cfq_hash); | |
1da177e4 LT |
2214 | out_crqhash: |
2215 | kfree(cfqd); | |
bc1c1169 | 2216 | return NULL; |
1da177e4 LT |
2217 | } |
2218 | ||
2219 | static void cfq_slab_kill(void) | |
2220 | { | |
2221 | if (crq_pool) | |
2222 | kmem_cache_destroy(crq_pool); | |
2223 | if (cfq_pool) | |
2224 | kmem_cache_destroy(cfq_pool); | |
2225 | if (cfq_ioc_pool) | |
2226 | kmem_cache_destroy(cfq_ioc_pool); | |
2227 | } | |
2228 | ||
2229 | static int __init cfq_slab_setup(void) | |
2230 | { | |
2231 | crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, | |
2232 | NULL, NULL); | |
2233 | if (!crq_pool) | |
2234 | goto fail; | |
2235 | ||
2236 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, | |
2237 | NULL, NULL); | |
2238 | if (!cfq_pool) | |
2239 | goto fail; | |
2240 | ||
2241 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", | |
2242 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); | |
2243 | if (!cfq_ioc_pool) | |
2244 | goto fail; | |
2245 | ||
2246 | return 0; | |
2247 | fail: | |
2248 | cfq_slab_kill(); | |
2249 | return -ENOMEM; | |
2250 | } | |
2251 | ||
1da177e4 LT |
2252 | /* |
2253 | * sysfs parts below --> | |
2254 | */ | |
1da177e4 LT |
2255 | |
2256 | static ssize_t | |
2257 | cfq_var_show(unsigned int var, char *page) | |
2258 | { | |
2259 | return sprintf(page, "%d\n", var); | |
2260 | } | |
2261 | ||
2262 | static ssize_t | |
2263 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
2264 | { | |
2265 | char *p = (char *) page; | |
2266 | ||
2267 | *var = simple_strtoul(p, &p, 10); | |
2268 | return count; | |
2269 | } | |
2270 | ||
1da177e4 | 2271 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
3d1ab40f | 2272 | static ssize_t __FUNC(elevator_t *e, char *page) \ |
1da177e4 | 2273 | { \ |
3d1ab40f | 2274 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
2275 | unsigned int __data = __VAR; \ |
2276 | if (__CONV) \ | |
2277 | __data = jiffies_to_msecs(__data); \ | |
2278 | return cfq_var_show(__data, (page)); \ | |
2279 | } | |
2280 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
2281 | SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); | |
22e2c507 JA |
2282 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
2283 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
e572ec7e AV |
2284 | SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); |
2285 | SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
2286 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
2287 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
2288 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
2289 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
1da177e4 LT |
2290 | #undef SHOW_FUNCTION |
2291 | ||
2292 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
3d1ab40f | 2293 | static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ |
1da177e4 | 2294 | { \ |
3d1ab40f | 2295 | struct cfq_data *cfqd = e->elevator_data; \ |
1da177e4 LT |
2296 | unsigned int __data; \ |
2297 | int ret = cfq_var_store(&__data, (page), count); \ | |
2298 | if (__data < (MIN)) \ | |
2299 | __data = (MIN); \ | |
2300 | else if (__data > (MAX)) \ | |
2301 | __data = (MAX); \ | |
2302 | if (__CONV) \ | |
2303 | *(__PTR) = msecs_to_jiffies(__data); \ | |
2304 | else \ | |
2305 | *(__PTR) = __data; \ | |
2306 | return ret; \ | |
2307 | } | |
2308 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
2309 | STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); | |
22e2c507 JA |
2310 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); |
2311 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); | |
e572ec7e AV |
2312 | STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
2313 | STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); | |
22e2c507 JA |
2314 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
2315 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
2316 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
2317 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); | |
1da177e4 LT |
2318 | #undef STORE_FUNCTION |
2319 | ||
e572ec7e AV |
2320 | #define CFQ_ATTR(name) \ |
2321 | __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) | |
2322 | ||
2323 | static struct elv_fs_entry cfq_attrs[] = { | |
2324 | CFQ_ATTR(quantum), | |
2325 | CFQ_ATTR(queued), | |
2326 | CFQ_ATTR(fifo_expire_sync), | |
2327 | CFQ_ATTR(fifo_expire_async), | |
2328 | CFQ_ATTR(back_seek_max), | |
2329 | CFQ_ATTR(back_seek_penalty), | |
2330 | CFQ_ATTR(slice_sync), | |
2331 | CFQ_ATTR(slice_async), | |
2332 | CFQ_ATTR(slice_async_rq), | |
2333 | CFQ_ATTR(slice_idle), | |
e572ec7e | 2334 | __ATTR_NULL |
1da177e4 LT |
2335 | }; |
2336 | ||
1da177e4 LT |
2337 | static struct elevator_type iosched_cfq = { |
2338 | .ops = { | |
2339 | .elevator_merge_fn = cfq_merge, | |
2340 | .elevator_merged_fn = cfq_merged_request, | |
2341 | .elevator_merge_req_fn = cfq_merged_requests, | |
b4878f24 | 2342 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 2343 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 2344 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
2345 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
2346 | .elevator_queue_empty_fn = cfq_queue_empty, | |
2347 | .elevator_completed_req_fn = cfq_completed_request, | |
2348 | .elevator_former_req_fn = cfq_former_request, | |
2349 | .elevator_latter_req_fn = cfq_latter_request, | |
2350 | .elevator_set_req_fn = cfq_set_request, | |
2351 | .elevator_put_req_fn = cfq_put_request, | |
2352 | .elevator_may_queue_fn = cfq_may_queue, | |
2353 | .elevator_init_fn = cfq_init_queue, | |
2354 | .elevator_exit_fn = cfq_exit_queue, | |
e17a9489 | 2355 | .trim = cfq_trim, |
1da177e4 | 2356 | }, |
3d1ab40f | 2357 | .elevator_attrs = cfq_attrs, |
1da177e4 LT |
2358 | .elevator_name = "cfq", |
2359 | .elevator_owner = THIS_MODULE, | |
2360 | }; | |
2361 | ||
2362 | static int __init cfq_init(void) | |
2363 | { | |
2364 | int ret; | |
2365 | ||
22e2c507 JA |
2366 | /* |
2367 | * could be 0 on HZ < 1000 setups | |
2368 | */ | |
2369 | if (!cfq_slice_async) | |
2370 | cfq_slice_async = 1; | |
2371 | if (!cfq_slice_idle) | |
2372 | cfq_slice_idle = 1; | |
2373 | ||
1da177e4 LT |
2374 | if (cfq_slab_setup()) |
2375 | return -ENOMEM; | |
2376 | ||
2377 | ret = elv_register(&iosched_cfq); | |
22e2c507 JA |
2378 | if (ret) |
2379 | cfq_slab_kill(); | |
1da177e4 | 2380 | |
1da177e4 LT |
2381 | return ret; |
2382 | } | |
2383 | ||
2384 | static void __exit cfq_exit(void) | |
2385 | { | |
334e94de | 2386 | DECLARE_COMPLETION(all_gone); |
1da177e4 | 2387 | elv_unregister(&iosched_cfq); |
334e94de | 2388 | ioc_gone = &all_gone; |
fba82272 OH |
2389 | /* ioc_gone's update must be visible before reading ioc_count */ |
2390 | smp_wmb(); | |
334e94de | 2391 | if (atomic_read(&ioc_count)) |
fba82272 | 2392 | wait_for_completion(ioc_gone); |
334e94de | 2393 | synchronize_rcu(); |
83521d3e | 2394 | cfq_slab_kill(); |
1da177e4 LT |
2395 | } |
2396 | ||
2397 | module_init(cfq_init); | |
2398 | module_exit(cfq_exit); | |
2399 | ||
2400 | MODULE_AUTHOR("Jens Axboe"); | |
2401 | MODULE_LICENSE("GPL"); | |
2402 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |