Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * CFQ, or complete fairness queueing, disk scheduler. |
3 | * | |
4 | * Based on ideas from a previously unfinished io | |
5 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. | |
6 | * | |
7 | * Copyright (C) 2003 Jens Axboe <axboe@suse.de> | |
8 | */ | |
9 | #include <linux/kernel.h> | |
10 | #include <linux/fs.h> | |
11 | #include <linux/blkdev.h> | |
12 | #include <linux/elevator.h> | |
13 | #include <linux/bio.h> | |
14 | #include <linux/config.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/compiler.h> | |
19 | #include <linux/hash.h> | |
20 | #include <linux/rbtree.h> | |
21 | #include <linux/mempool.h> | |
22e2c507 JA |
22 | #include <linux/ioprio.h> |
23 | #include <linux/writeback.h> | |
1da177e4 LT |
24 | |
25 | /* | |
26 | * tunables | |
27 | */ | |
64100099 AV |
28 | static const int cfq_quantum = 4; /* max queue in one round of service */ |
29 | static const int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ | |
30 | static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; | |
31 | static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ | |
32 | static const int cfq_back_penalty = 2; /* penalty of a backwards seek */ | |
1da177e4 | 33 | |
64100099 | 34 | static const int cfq_slice_sync = HZ / 10; |
3b18152c | 35 | static int cfq_slice_async = HZ / 25; |
64100099 | 36 | static const int cfq_slice_async_rq = 2; |
3b18152c | 37 | static int cfq_slice_idle = HZ / 100; |
22e2c507 JA |
38 | |
39 | #define CFQ_IDLE_GRACE (HZ / 10) | |
40 | #define CFQ_SLICE_SCALE (5) | |
41 | ||
42 | #define CFQ_KEY_ASYNC (0) | |
3b18152c | 43 | #define CFQ_KEY_ANY (0xffff) |
22e2c507 JA |
44 | |
45 | /* | |
46 | * disable queueing at the driver/hardware level | |
47 | */ | |
64100099 | 48 | static const int cfq_max_depth = 2; |
22e2c507 | 49 | |
a6a0763a AV |
50 | static DEFINE_RWLOCK(cfq_exit_lock); |
51 | ||
1da177e4 LT |
52 | /* |
53 | * for the hash of cfqq inside the cfqd | |
54 | */ | |
55 | #define CFQ_QHASH_SHIFT 6 | |
56 | #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) | |
57 | #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) | |
58 | ||
59 | /* | |
60 | * for the hash of crq inside the cfqq | |
61 | */ | |
62 | #define CFQ_MHASH_SHIFT 6 | |
63 | #define CFQ_MHASH_BLOCK(sec) ((sec) >> 3) | |
64 | #define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT) | |
65 | #define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT) | |
66 | #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) | |
67 | #define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash) | |
68 | ||
69 | #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) | |
22e2c507 | 70 | #define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
1da177e4 LT |
71 | |
72 | #define RQ_DATA(rq) (rq)->elevator_private | |
73 | ||
74 | /* | |
75 | * rb-tree defines | |
76 | */ | |
77 | #define RB_NONE (2) | |
78 | #define RB_EMPTY(node) ((node)->rb_node == NULL) | |
79 | #define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE | |
80 | #define RB_CLEAR(node) do { \ | |
81 | (node)->rb_parent = NULL; \ | |
82 | RB_CLEAR_COLOR((node)); \ | |
83 | (node)->rb_right = NULL; \ | |
84 | (node)->rb_left = NULL; \ | |
85 | } while (0) | |
86 | #define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL) | |
1da177e4 LT |
87 | #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) |
88 | #define rq_rb_key(rq) (rq)->sector | |
89 | ||
1da177e4 LT |
90 | static kmem_cache_t *crq_pool; |
91 | static kmem_cache_t *cfq_pool; | |
92 | static kmem_cache_t *cfq_ioc_pool; | |
93 | ||
334e94de AV |
94 | static atomic_t ioc_count = ATOMIC_INIT(0); |
95 | static struct completion *ioc_gone; | |
96 | ||
22e2c507 JA |
97 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
98 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
99 | #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) | |
100 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) | |
101 | ||
3b18152c JA |
102 | #define ASYNC (0) |
103 | #define SYNC (1) | |
104 | ||
105 | #define cfq_cfqq_dispatched(cfqq) \ | |
106 | ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) | |
107 | ||
108 | #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) | |
109 | ||
110 | #define cfq_cfqq_sync(cfqq) \ | |
111 | (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) | |
22e2c507 JA |
112 | |
113 | /* | |
114 | * Per block device queue structure | |
115 | */ | |
1da177e4 | 116 | struct cfq_data { |
22e2c507 JA |
117 | request_queue_t *queue; |
118 | ||
119 | /* | |
120 | * rr list of queues with requests and the count of them | |
121 | */ | |
122 | struct list_head rr_list[CFQ_PRIO_LISTS]; | |
123 | struct list_head busy_rr; | |
124 | struct list_head cur_rr; | |
125 | struct list_head idle_rr; | |
126 | unsigned int busy_queues; | |
127 | ||
128 | /* | |
129 | * non-ordered list of empty cfqq's | |
130 | */ | |
1da177e4 LT |
131 | struct list_head empty_list; |
132 | ||
22e2c507 JA |
133 | /* |
134 | * cfqq lookup hash | |
135 | */ | |
1da177e4 | 136 | struct hlist_head *cfq_hash; |
1da177e4 | 137 | |
22e2c507 JA |
138 | /* |
139 | * global crq hash for all queues | |
140 | */ | |
141 | struct hlist_head *crq_hash; | |
1da177e4 LT |
142 | |
143 | unsigned int max_queued; | |
144 | ||
22e2c507 | 145 | mempool_t *crq_pool; |
1da177e4 | 146 | |
22e2c507 | 147 | int rq_in_driver; |
1da177e4 | 148 | |
22e2c507 JA |
149 | /* |
150 | * schedule slice state info | |
151 | */ | |
152 | /* | |
153 | * idle window management | |
154 | */ | |
155 | struct timer_list idle_slice_timer; | |
156 | struct work_struct unplug_work; | |
1da177e4 | 157 | |
22e2c507 JA |
158 | struct cfq_queue *active_queue; |
159 | struct cfq_io_context *active_cic; | |
160 | int cur_prio, cur_end_prio; | |
161 | unsigned int dispatch_slice; | |
162 | ||
163 | struct timer_list idle_class_timer; | |
1da177e4 LT |
164 | |
165 | sector_t last_sector; | |
22e2c507 | 166 | unsigned long last_end_request; |
1da177e4 | 167 | |
22e2c507 | 168 | unsigned int rq_starved; |
1da177e4 LT |
169 | |
170 | /* | |
171 | * tunables, see top of file | |
172 | */ | |
173 | unsigned int cfq_quantum; | |
174 | unsigned int cfq_queued; | |
22e2c507 | 175 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
176 | unsigned int cfq_back_penalty; |
177 | unsigned int cfq_back_max; | |
22e2c507 JA |
178 | unsigned int cfq_slice[2]; |
179 | unsigned int cfq_slice_async_rq; | |
180 | unsigned int cfq_slice_idle; | |
181 | unsigned int cfq_max_depth; | |
d9ff4187 AV |
182 | |
183 | struct list_head cic_list; | |
1da177e4 LT |
184 | }; |
185 | ||
22e2c507 JA |
186 | /* |
187 | * Per process-grouping structure | |
188 | */ | |
1da177e4 LT |
189 | struct cfq_queue { |
190 | /* reference count */ | |
191 | atomic_t ref; | |
192 | /* parent cfq_data */ | |
193 | struct cfq_data *cfqd; | |
22e2c507 | 194 | /* cfqq lookup hash */ |
1da177e4 LT |
195 | struct hlist_node cfq_hash; |
196 | /* hash key */ | |
22e2c507 | 197 | unsigned int key; |
1da177e4 LT |
198 | /* on either rr or empty list of cfqd */ |
199 | struct list_head cfq_list; | |
200 | /* sorted list of pending requests */ | |
201 | struct rb_root sort_list; | |
202 | /* if fifo isn't expired, next request to serve */ | |
203 | struct cfq_rq *next_crq; | |
204 | /* requests queued in sort_list */ | |
205 | int queued[2]; | |
206 | /* currently allocated requests */ | |
207 | int allocated[2]; | |
208 | /* fifo list of requests in sort_list */ | |
22e2c507 | 209 | struct list_head fifo; |
1da177e4 | 210 | |
22e2c507 JA |
211 | unsigned long slice_start; |
212 | unsigned long slice_end; | |
213 | unsigned long slice_left; | |
214 | unsigned long service_last; | |
1da177e4 | 215 | |
3b18152c JA |
216 | /* number of requests that are on the dispatch list */ |
217 | int on_dispatch[2]; | |
22e2c507 JA |
218 | |
219 | /* io prio of this group */ | |
220 | unsigned short ioprio, org_ioprio; | |
221 | unsigned short ioprio_class, org_ioprio_class; | |
222 | ||
3b18152c JA |
223 | /* various state flags, see below */ |
224 | unsigned int flags; | |
1da177e4 LT |
225 | }; |
226 | ||
227 | struct cfq_rq { | |
228 | struct rb_node rb_node; | |
229 | sector_t rb_key; | |
230 | struct request *request; | |
231 | struct hlist_node hash; | |
232 | ||
233 | struct cfq_queue *cfq_queue; | |
234 | struct cfq_io_context *io_context; | |
235 | ||
3b18152c | 236 | unsigned int crq_flags; |
1da177e4 LT |
237 | }; |
238 | ||
3b18152c JA |
239 | enum cfqq_state_flags { |
240 | CFQ_CFQQ_FLAG_on_rr = 0, | |
241 | CFQ_CFQQ_FLAG_wait_request, | |
242 | CFQ_CFQQ_FLAG_must_alloc, | |
243 | CFQ_CFQQ_FLAG_must_alloc_slice, | |
244 | CFQ_CFQQ_FLAG_must_dispatch, | |
245 | CFQ_CFQQ_FLAG_fifo_expire, | |
246 | CFQ_CFQQ_FLAG_idle_window, | |
247 | CFQ_CFQQ_FLAG_prio_changed, | |
3b18152c JA |
248 | }; |
249 | ||
250 | #define CFQ_CFQQ_FNS(name) \ | |
251 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
252 | { \ | |
253 | cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ | |
254 | } \ | |
255 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
256 | { \ | |
257 | cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ | |
258 | } \ | |
259 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
260 | { \ | |
261 | return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ | |
262 | } | |
263 | ||
264 | CFQ_CFQQ_FNS(on_rr); | |
265 | CFQ_CFQQ_FNS(wait_request); | |
266 | CFQ_CFQQ_FNS(must_alloc); | |
267 | CFQ_CFQQ_FNS(must_alloc_slice); | |
268 | CFQ_CFQQ_FNS(must_dispatch); | |
269 | CFQ_CFQQ_FNS(fifo_expire); | |
270 | CFQ_CFQQ_FNS(idle_window); | |
271 | CFQ_CFQQ_FNS(prio_changed); | |
3b18152c JA |
272 | #undef CFQ_CFQQ_FNS |
273 | ||
274 | enum cfq_rq_state_flags { | |
b4878f24 | 275 | CFQ_CRQ_FLAG_is_sync = 0, |
3b18152c JA |
276 | }; |
277 | ||
278 | #define CFQ_CRQ_FNS(name) \ | |
279 | static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \ | |
280 | { \ | |
281 | crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \ | |
282 | } \ | |
283 | static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \ | |
284 | { \ | |
285 | crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \ | |
286 | } \ | |
287 | static inline int cfq_crq_##name(const struct cfq_rq *crq) \ | |
288 | { \ | |
289 | return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \ | |
290 | } | |
291 | ||
3b18152c | 292 | CFQ_CRQ_FNS(is_sync); |
3b18152c JA |
293 | #undef CFQ_CRQ_FNS |
294 | ||
295 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); | |
b4878f24 | 296 | static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); |
6f325a13 | 297 | static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); |
1da177e4 | 298 | |
22e2c507 | 299 | #define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) |
1da177e4 LT |
300 | |
301 | /* | |
302 | * lots of deadline iosched dupes, can be abstracted later... | |
303 | */ | |
304 | static inline void cfq_del_crq_hash(struct cfq_rq *crq) | |
305 | { | |
306 | hlist_del_init(&crq->hash); | |
307 | } | |
308 | ||
1da177e4 LT |
309 | static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) |
310 | { | |
311 | const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); | |
312 | ||
1da177e4 LT |
313 | hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); |
314 | } | |
315 | ||
316 | static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) | |
317 | { | |
318 | struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)]; | |
319 | struct hlist_node *entry, *next; | |
320 | ||
321 | hlist_for_each_safe(entry, next, hash_list) { | |
322 | struct cfq_rq *crq = list_entry_hash(entry); | |
323 | struct request *__rq = crq->request; | |
324 | ||
1da177e4 LT |
325 | if (!rq_mergeable(__rq)) { |
326 | cfq_del_crq_hash(crq); | |
327 | continue; | |
328 | } | |
329 | ||
330 | if (rq_hash_key(__rq) == offset) | |
331 | return __rq; | |
332 | } | |
333 | ||
334 | return NULL; | |
335 | } | |
336 | ||
99f95e52 AM |
337 | /* |
338 | * scheduler run of queue, if there are requests pending and no one in the | |
339 | * driver that will restart queueing | |
340 | */ | |
341 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) | |
342 | { | |
7b14e3b5 | 343 | if (cfqd->busy_queues) |
99f95e52 AM |
344 | kblockd_schedule_work(&cfqd->unplug_work); |
345 | } | |
346 | ||
347 | static int cfq_queue_empty(request_queue_t *q) | |
348 | { | |
349 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
350 | ||
b4878f24 | 351 | return !cfqd->busy_queues; |
99f95e52 AM |
352 | } |
353 | ||
1da177e4 LT |
354 | /* |
355 | * Lifted from AS - choose which of crq1 and crq2 that is best served now. | |
356 | * We choose the request that is closest to the head right now. Distance | |
357 | * behind the head are penalized and only allowed to a certain extent. | |
358 | */ | |
359 | static struct cfq_rq * | |
360 | cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) | |
361 | { | |
362 | sector_t last, s1, s2, d1 = 0, d2 = 0; | |
363 | int r1_wrap = 0, r2_wrap = 0; /* requests are behind the disk head */ | |
364 | unsigned long back_max; | |
365 | ||
366 | if (crq1 == NULL || crq1 == crq2) | |
367 | return crq2; | |
368 | if (crq2 == NULL) | |
369 | return crq1; | |
9c2c38a1 | 370 | |
9c2c38a1 JA |
371 | if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2)) |
372 | return crq1; | |
373 | else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1)) | |
22e2c507 | 374 | return crq2; |
1da177e4 LT |
375 | |
376 | s1 = crq1->request->sector; | |
377 | s2 = crq2->request->sector; | |
378 | ||
379 | last = cfqd->last_sector; | |
380 | ||
1da177e4 LT |
381 | /* |
382 | * by definition, 1KiB is 2 sectors | |
383 | */ | |
384 | back_max = cfqd->cfq_back_max * 2; | |
385 | ||
386 | /* | |
387 | * Strict one way elevator _except_ in the case where we allow | |
388 | * short backward seeks which are biased as twice the cost of a | |
389 | * similar forward seek. | |
390 | */ | |
391 | if (s1 >= last) | |
392 | d1 = s1 - last; | |
393 | else if (s1 + back_max >= last) | |
394 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
395 | else | |
396 | r1_wrap = 1; | |
397 | ||
398 | if (s2 >= last) | |
399 | d2 = s2 - last; | |
400 | else if (s2 + back_max >= last) | |
401 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
402 | else | |
403 | r2_wrap = 1; | |
404 | ||
405 | /* Found required data */ | |
406 | if (!r1_wrap && r2_wrap) | |
407 | return crq1; | |
408 | else if (!r2_wrap && r1_wrap) | |
409 | return crq2; | |
410 | else if (r1_wrap && r2_wrap) { | |
411 | /* both behind the head */ | |
412 | if (s1 <= s2) | |
413 | return crq1; | |
414 | else | |
415 | return crq2; | |
416 | } | |
417 | ||
418 | /* Both requests in front of the head */ | |
419 | if (d1 < d2) | |
420 | return crq1; | |
421 | else if (d2 < d1) | |
422 | return crq2; | |
423 | else { | |
424 | if (s1 >= s2) | |
425 | return crq1; | |
426 | else | |
427 | return crq2; | |
428 | } | |
429 | } | |
430 | ||
431 | /* | |
432 | * would be nice to take fifo expire time into account as well | |
433 | */ | |
434 | static struct cfq_rq * | |
435 | cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
436 | struct cfq_rq *last) | |
437 | { | |
438 | struct cfq_rq *crq_next = NULL, *crq_prev = NULL; | |
439 | struct rb_node *rbnext, *rbprev; | |
440 | ||
b4878f24 | 441 | if (!(rbnext = rb_next(&last->rb_node))) { |
1da177e4 | 442 | rbnext = rb_first(&cfqq->sort_list); |
22e2c507 JA |
443 | if (rbnext == &last->rb_node) |
444 | rbnext = NULL; | |
445 | } | |
1da177e4 LT |
446 | |
447 | rbprev = rb_prev(&last->rb_node); | |
448 | ||
449 | if (rbprev) | |
450 | crq_prev = rb_entry_crq(rbprev); | |
451 | if (rbnext) | |
452 | crq_next = rb_entry_crq(rbnext); | |
453 | ||
454 | return cfq_choose_req(cfqd, crq_next, crq_prev); | |
455 | } | |
456 | ||
457 | static void cfq_update_next_crq(struct cfq_rq *crq) | |
458 | { | |
459 | struct cfq_queue *cfqq = crq->cfq_queue; | |
460 | ||
461 | if (cfqq->next_crq == crq) | |
462 | cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); | |
463 | } | |
464 | ||
22e2c507 | 465 | static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
1da177e4 | 466 | { |
22e2c507 JA |
467 | struct cfq_data *cfqd = cfqq->cfqd; |
468 | struct list_head *list, *entry; | |
1da177e4 | 469 | |
3b18152c | 470 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 471 | |
22e2c507 | 472 | list_del(&cfqq->cfq_list); |
1da177e4 | 473 | |
22e2c507 JA |
474 | if (cfq_class_rt(cfqq)) |
475 | list = &cfqd->cur_rr; | |
476 | else if (cfq_class_idle(cfqq)) | |
477 | list = &cfqd->idle_rr; | |
478 | else { | |
479 | /* | |
480 | * if cfqq has requests in flight, don't allow it to be | |
481 | * found in cfq_set_active_queue before it has finished them. | |
482 | * this is done to increase fairness between a process that | |
483 | * has lots of io pending vs one that only generates one | |
484 | * sporadically or synchronously | |
485 | */ | |
3b18152c | 486 | if (cfq_cfqq_dispatched(cfqq)) |
22e2c507 JA |
487 | list = &cfqd->busy_rr; |
488 | else | |
489 | list = &cfqd->rr_list[cfqq->ioprio]; | |
1da177e4 LT |
490 | } |
491 | ||
22e2c507 JA |
492 | /* |
493 | * if queue was preempted, just add to front to be fair. busy_rr | |
494 | * isn't sorted. | |
495 | */ | |
496 | if (preempted || list == &cfqd->busy_rr) { | |
497 | list_add(&cfqq->cfq_list, list); | |
1da177e4 | 498 | return; |
22e2c507 | 499 | } |
1da177e4 LT |
500 | |
501 | /* | |
22e2c507 | 502 | * sort by when queue was last serviced |
1da177e4 | 503 | */ |
22e2c507 JA |
504 | entry = list; |
505 | while ((entry = entry->prev) != list) { | |
1da177e4 LT |
506 | struct cfq_queue *__cfqq = list_entry_cfqq(entry); |
507 | ||
22e2c507 JA |
508 | if (!__cfqq->service_last) |
509 | break; | |
510 | if (time_before(__cfqq->service_last, cfqq->service_last)) | |
1da177e4 | 511 | break; |
1da177e4 LT |
512 | } |
513 | ||
514 | list_add(&cfqq->cfq_list, entry); | |
515 | } | |
516 | ||
517 | /* | |
518 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 519 | * the pending list according to last request service |
1da177e4 LT |
520 | */ |
521 | static inline void | |
b4878f24 | 522 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 523 | { |
3b18152c JA |
524 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
525 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
526 | cfqd->busy_queues++; |
527 | ||
b4878f24 | 528 | cfq_resort_rr_list(cfqq, 0); |
1da177e4 LT |
529 | } |
530 | ||
531 | static inline void | |
532 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
533 | { | |
3b18152c JA |
534 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
535 | cfq_clear_cfqq_on_rr(cfqq); | |
22e2c507 | 536 | list_move(&cfqq->cfq_list, &cfqd->empty_list); |
1da177e4 LT |
537 | |
538 | BUG_ON(!cfqd->busy_queues); | |
539 | cfqd->busy_queues--; | |
540 | } | |
541 | ||
542 | /* | |
543 | * rb tree support functions | |
544 | */ | |
545 | static inline void cfq_del_crq_rb(struct cfq_rq *crq) | |
546 | { | |
547 | struct cfq_queue *cfqq = crq->cfq_queue; | |
b4878f24 JA |
548 | struct cfq_data *cfqd = cfqq->cfqd; |
549 | const int sync = cfq_crq_is_sync(crq); | |
1da177e4 | 550 | |
b4878f24 JA |
551 | BUG_ON(!cfqq->queued[sync]); |
552 | cfqq->queued[sync]--; | |
1da177e4 | 553 | |
b4878f24 | 554 | cfq_update_next_crq(crq); |
1da177e4 | 555 | |
b4878f24 JA |
556 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
557 | RB_CLEAR_COLOR(&crq->rb_node); | |
1da177e4 | 558 | |
b4878f24 JA |
559 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list)) |
560 | cfq_del_cfqq_rr(cfqd, cfqq); | |
1da177e4 LT |
561 | } |
562 | ||
563 | static struct cfq_rq * | |
564 | __cfq_add_crq_rb(struct cfq_rq *crq) | |
565 | { | |
566 | struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; | |
567 | struct rb_node *parent = NULL; | |
568 | struct cfq_rq *__crq; | |
569 | ||
570 | while (*p) { | |
571 | parent = *p; | |
572 | __crq = rb_entry_crq(parent); | |
573 | ||
574 | if (crq->rb_key < __crq->rb_key) | |
575 | p = &(*p)->rb_left; | |
576 | else if (crq->rb_key > __crq->rb_key) | |
577 | p = &(*p)->rb_right; | |
578 | else | |
579 | return __crq; | |
580 | } | |
581 | ||
582 | rb_link_node(&crq->rb_node, parent, p); | |
583 | return NULL; | |
584 | } | |
585 | ||
586 | static void cfq_add_crq_rb(struct cfq_rq *crq) | |
587 | { | |
588 | struct cfq_queue *cfqq = crq->cfq_queue; | |
589 | struct cfq_data *cfqd = cfqq->cfqd; | |
590 | struct request *rq = crq->request; | |
591 | struct cfq_rq *__alias; | |
592 | ||
593 | crq->rb_key = rq_rb_key(rq); | |
3b18152c | 594 | cfqq->queued[cfq_crq_is_sync(crq)]++; |
1da177e4 LT |
595 | |
596 | /* | |
597 | * looks a little odd, but the first insert might return an alias. | |
598 | * if that happens, put the alias on the dispatch list | |
599 | */ | |
600 | while ((__alias = __cfq_add_crq_rb(crq)) != NULL) | |
b4878f24 | 601 | cfq_dispatch_insert(cfqd->queue, __alias); |
1da177e4 LT |
602 | |
603 | rb_insert_color(&crq->rb_node, &cfqq->sort_list); | |
604 | ||
3b18152c | 605 | if (!cfq_cfqq_on_rr(cfqq)) |
b4878f24 | 606 | cfq_add_cfqq_rr(cfqd, cfqq); |
1da177e4 LT |
607 | |
608 | /* | |
609 | * check if this request is a better next-serve candidate | |
610 | */ | |
611 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
612 | } | |
613 | ||
614 | static inline void | |
615 | cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) | |
616 | { | |
b4878f24 JA |
617 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
618 | cfqq->queued[cfq_crq_is_sync(crq)]--; | |
1da177e4 LT |
619 | |
620 | cfq_add_crq_rb(crq); | |
621 | } | |
622 | ||
22e2c507 JA |
623 | static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) |
624 | ||
1da177e4 | 625 | { |
3b18152c | 626 | struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY); |
1da177e4 LT |
627 | struct rb_node *n; |
628 | ||
629 | if (!cfqq) | |
630 | goto out; | |
631 | ||
632 | n = cfqq->sort_list.rb_node; | |
633 | while (n) { | |
634 | struct cfq_rq *crq = rb_entry_crq(n); | |
635 | ||
636 | if (sector < crq->rb_key) | |
637 | n = n->rb_left; | |
638 | else if (sector > crq->rb_key) | |
639 | n = n->rb_right; | |
640 | else | |
641 | return crq->request; | |
642 | } | |
643 | ||
644 | out: | |
645 | return NULL; | |
646 | } | |
647 | ||
b4878f24 | 648 | static void cfq_activate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 649 | { |
22e2c507 | 650 | struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c | 651 | |
b4878f24 | 652 | cfqd->rq_in_driver++; |
1da177e4 LT |
653 | } |
654 | ||
b4878f24 | 655 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) |
1da177e4 | 656 | { |
b4878f24 JA |
657 | struct cfq_data *cfqd = q->elevator->elevator_data; |
658 | ||
659 | WARN_ON(!cfqd->rq_in_driver); | |
660 | cfqd->rq_in_driver--; | |
1da177e4 LT |
661 | } |
662 | ||
b4878f24 | 663 | static void cfq_remove_request(struct request *rq) |
1da177e4 LT |
664 | { |
665 | struct cfq_rq *crq = RQ_DATA(rq); | |
666 | ||
b4878f24 JA |
667 | list_del_init(&rq->queuelist); |
668 | cfq_del_crq_rb(crq); | |
98b11471 | 669 | cfq_del_crq_hash(crq); |
1da177e4 LT |
670 | } |
671 | ||
672 | static int | |
673 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
674 | { | |
675 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
676 | struct request *__rq; | |
677 | int ret; | |
678 | ||
1da177e4 | 679 | __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); |
22e2c507 JA |
680 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
681 | ret = ELEVATOR_BACK_MERGE; | |
682 | goto out; | |
1da177e4 LT |
683 | } |
684 | ||
685 | __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); | |
22e2c507 JA |
686 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
687 | ret = ELEVATOR_FRONT_MERGE; | |
688 | goto out; | |
1da177e4 LT |
689 | } |
690 | ||
691 | return ELEVATOR_NO_MERGE; | |
692 | out: | |
1da177e4 LT |
693 | *req = __rq; |
694 | return ret; | |
695 | } | |
696 | ||
697 | static void cfq_merged_request(request_queue_t *q, struct request *req) | |
698 | { | |
699 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
700 | struct cfq_rq *crq = RQ_DATA(req); | |
701 | ||
702 | cfq_del_crq_hash(crq); | |
703 | cfq_add_crq_hash(cfqd, crq); | |
704 | ||
b4878f24 | 705 | if (rq_rb_key(req) != crq->rb_key) { |
1da177e4 LT |
706 | struct cfq_queue *cfqq = crq->cfq_queue; |
707 | ||
708 | cfq_update_next_crq(crq); | |
709 | cfq_reposition_crq_rb(cfqq, crq); | |
710 | } | |
1da177e4 LT |
711 | } |
712 | ||
713 | static void | |
714 | cfq_merged_requests(request_queue_t *q, struct request *rq, | |
715 | struct request *next) | |
716 | { | |
1da177e4 LT |
717 | cfq_merged_request(q, rq); |
718 | ||
22e2c507 JA |
719 | /* |
720 | * reposition in fifo if next is older than rq | |
721 | */ | |
722 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
723 | time_before(next->start_time, rq->start_time)) | |
724 | list_move(&rq->queuelist, &next->queuelist); | |
725 | ||
b4878f24 | 726 | cfq_remove_request(next); |
22e2c507 JA |
727 | } |
728 | ||
729 | static inline void | |
730 | __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
731 | { | |
732 | if (cfqq) { | |
733 | /* | |
734 | * stop potential idle class queues waiting service | |
735 | */ | |
736 | del_timer(&cfqd->idle_class_timer); | |
737 | ||
738 | cfqq->slice_start = jiffies; | |
739 | cfqq->slice_end = 0; | |
740 | cfqq->slice_left = 0; | |
3b18152c JA |
741 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
742 | cfq_clear_cfqq_fifo_expire(cfqq); | |
22e2c507 JA |
743 | } |
744 | ||
745 | cfqd->active_queue = cfqq; | |
746 | } | |
747 | ||
7b14e3b5 JA |
748 | /* |
749 | * current cfqq expired its slice (or was too idle), select new one | |
750 | */ | |
751 | static void | |
752 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
753 | int preempted) | |
754 | { | |
755 | unsigned long now = jiffies; | |
756 | ||
757 | if (cfq_cfqq_wait_request(cfqq)) | |
758 | del_timer(&cfqd->idle_slice_timer); | |
759 | ||
760 | if (!preempted && !cfq_cfqq_dispatched(cfqq)) { | |
761 | cfqq->service_last = now; | |
762 | cfq_schedule_dispatch(cfqd); | |
763 | } | |
764 | ||
765 | cfq_clear_cfqq_must_dispatch(cfqq); | |
766 | cfq_clear_cfqq_wait_request(cfqq); | |
767 | ||
768 | /* | |
769 | * store what was left of this slice, if the queue idled out | |
770 | * or was preempted | |
771 | */ | |
772 | if (time_after(cfqq->slice_end, now)) | |
773 | cfqq->slice_left = cfqq->slice_end - now; | |
774 | else | |
775 | cfqq->slice_left = 0; | |
776 | ||
777 | if (cfq_cfqq_on_rr(cfqq)) | |
778 | cfq_resort_rr_list(cfqq, preempted); | |
779 | ||
780 | if (cfqq == cfqd->active_queue) | |
781 | cfqd->active_queue = NULL; | |
782 | ||
783 | if (cfqd->active_cic) { | |
784 | put_io_context(cfqd->active_cic->ioc); | |
785 | cfqd->active_cic = NULL; | |
786 | } | |
787 | ||
788 | cfqd->dispatch_slice = 0; | |
789 | } | |
790 | ||
791 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) | |
792 | { | |
793 | struct cfq_queue *cfqq = cfqd->active_queue; | |
794 | ||
795 | if (cfqq) | |
796 | __cfq_slice_expired(cfqd, cfqq, preempted); | |
797 | } | |
798 | ||
22e2c507 JA |
799 | /* |
800 | * 0 | |
801 | * 0,1 | |
802 | * 0,1,2 | |
803 | * 0,1,2,3 | |
804 | * 0,1,2,3,4 | |
805 | * 0,1,2,3,4,5 | |
806 | * 0,1,2,3,4,5,6 | |
807 | * 0,1,2,3,4,5,6,7 | |
808 | */ | |
809 | static int cfq_get_next_prio_level(struct cfq_data *cfqd) | |
810 | { | |
811 | int prio, wrap; | |
812 | ||
813 | prio = -1; | |
814 | wrap = 0; | |
815 | do { | |
816 | int p; | |
817 | ||
818 | for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { | |
819 | if (!list_empty(&cfqd->rr_list[p])) { | |
820 | prio = p; | |
821 | break; | |
822 | } | |
823 | } | |
824 | ||
825 | if (prio != -1) | |
826 | break; | |
827 | cfqd->cur_prio = 0; | |
828 | if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
829 | cfqd->cur_end_prio = 0; | |
830 | if (wrap) | |
831 | break; | |
832 | wrap = 1; | |
1da177e4 | 833 | } |
22e2c507 JA |
834 | } while (1); |
835 | ||
836 | if (unlikely(prio == -1)) | |
837 | return -1; | |
838 | ||
839 | BUG_ON(prio >= CFQ_PRIO_LISTS); | |
840 | ||
841 | list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); | |
842 | ||
843 | cfqd->cur_prio = prio + 1; | |
844 | if (cfqd->cur_prio > cfqd->cur_end_prio) { | |
845 | cfqd->cur_end_prio = cfqd->cur_prio; | |
846 | cfqd->cur_prio = 0; | |
847 | } | |
848 | if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
849 | cfqd->cur_prio = 0; | |
850 | cfqd->cur_end_prio = 0; | |
1da177e4 LT |
851 | } |
852 | ||
22e2c507 JA |
853 | return prio; |
854 | } | |
855 | ||
3b18152c | 856 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
22e2c507 | 857 | { |
7b14e3b5 | 858 | struct cfq_queue *cfqq = NULL; |
22e2c507 JA |
859 | |
860 | /* | |
861 | * if current list is non-empty, grab first entry. if it is empty, | |
862 | * get next prio level and grab first entry then if any are spliced | |
863 | */ | |
864 | if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) | |
865 | cfqq = list_entry_cfqq(cfqd->cur_rr.next); | |
866 | ||
867 | /* | |
868 | * if we have idle queues and no rt or be queues had pending | |
869 | * requests, either allow immediate service if the grace period | |
870 | * has passed or arm the idle grace timer | |
871 | */ | |
872 | if (!cfqq && !list_empty(&cfqd->idle_rr)) { | |
873 | unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
874 | ||
875 | if (time_after_eq(jiffies, end)) | |
876 | cfqq = list_entry_cfqq(cfqd->idle_rr.next); | |
877 | else | |
878 | mod_timer(&cfqd->idle_class_timer, end); | |
879 | } | |
880 | ||
881 | __cfq_set_active_queue(cfqd, cfqq); | |
3b18152c | 882 | return cfqq; |
22e2c507 JA |
883 | } |
884 | ||
22e2c507 JA |
885 | static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
886 | ||
887 | { | |
7b14e3b5 JA |
888 | unsigned long sl; |
889 | ||
22e2c507 JA |
890 | WARN_ON(!RB_EMPTY(&cfqq->sort_list)); |
891 | WARN_ON(cfqq != cfqd->active_queue); | |
892 | ||
893 | /* | |
894 | * idle is disabled, either manually or by past process history | |
895 | */ | |
896 | if (!cfqd->cfq_slice_idle) | |
897 | return 0; | |
3b18152c | 898 | if (!cfq_cfqq_idle_window(cfqq)) |
22e2c507 JA |
899 | return 0; |
900 | /* | |
901 | * task has exited, don't wait | |
902 | */ | |
903 | if (cfqd->active_cic && !cfqd->active_cic->ioc->task) | |
904 | return 0; | |
905 | ||
3b18152c JA |
906 | cfq_mark_cfqq_must_dispatch(cfqq); |
907 | cfq_mark_cfqq_wait_request(cfqq); | |
22e2c507 | 908 | |
7b14e3b5 JA |
909 | sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
910 | mod_timer(&cfqd->idle_slice_timer, jiffies + sl); | |
22e2c507 | 911 | return 1; |
1da177e4 LT |
912 | } |
913 | ||
b4878f24 | 914 | static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) |
1da177e4 LT |
915 | { |
916 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
917 | struct cfq_queue *cfqq = crq->cfq_queue; | |
22e2c507 JA |
918 | |
919 | cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); | |
b4878f24 | 920 | cfq_remove_request(crq->request); |
3b18152c | 921 | cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; |
b4878f24 | 922 | elv_dispatch_sort(q, crq->request); |
1da177e4 LT |
923 | } |
924 | ||
925 | /* | |
926 | * return expired entry, or NULL to just start from scratch in rbtree | |
927 | */ | |
928 | static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) | |
929 | { | |
930 | struct cfq_data *cfqd = cfqq->cfqd; | |
22e2c507 | 931 | struct request *rq; |
1da177e4 LT |
932 | struct cfq_rq *crq; |
933 | ||
3b18152c | 934 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 LT |
935 | return NULL; |
936 | ||
22e2c507 | 937 | if (!list_empty(&cfqq->fifo)) { |
3b18152c | 938 | int fifo = cfq_cfqq_class_sync(cfqq); |
1da177e4 | 939 | |
22e2c507 JA |
940 | crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); |
941 | rq = crq->request; | |
942 | if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { | |
3b18152c | 943 | cfq_mark_cfqq_fifo_expire(cfqq); |
22e2c507 JA |
944 | return crq; |
945 | } | |
1da177e4 LT |
946 | } |
947 | ||
948 | return NULL; | |
949 | } | |
950 | ||
951 | /* | |
3b18152c JA |
952 | * Scale schedule slice based on io priority. Use the sync time slice only |
953 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
954 | * io only, should not get full sync slice length. | |
1da177e4 | 955 | */ |
22e2c507 JA |
956 | static inline int |
957 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
958 | { | |
959 | const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; | |
960 | ||
961 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); | |
962 | ||
963 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); | |
964 | } | |
965 | ||
1da177e4 | 966 | static inline void |
22e2c507 | 967 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 968 | { |
22e2c507 JA |
969 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
970 | } | |
1da177e4 | 971 | |
22e2c507 JA |
972 | static inline int |
973 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
974 | { | |
975 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 976 | |
22e2c507 | 977 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 978 | |
22e2c507 | 979 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
980 | } |
981 | ||
22e2c507 JA |
982 | /* |
983 | * get next queue for service | |
984 | */ | |
1b5ed5e1 | 985 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4 | 986 | { |
22e2c507 | 987 | unsigned long now = jiffies; |
1da177e4 | 988 | struct cfq_queue *cfqq; |
1da177e4 | 989 | |
22e2c507 JA |
990 | cfqq = cfqd->active_queue; |
991 | if (!cfqq) | |
992 | goto new_queue; | |
1da177e4 | 993 | |
22e2c507 JA |
994 | /* |
995 | * slice has expired | |
996 | */ | |
3b18152c JA |
997 | if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) |
998 | goto expire; | |
1da177e4 | 999 | |
22e2c507 JA |
1000 | /* |
1001 | * if queue has requests, dispatch one. if not, check if | |
1002 | * enough slice is left to wait for one | |
1003 | */ | |
1004 | if (!RB_EMPTY(&cfqq->sort_list)) | |
1005 | goto keep_queue; | |
1b5ed5e1 | 1006 | else if (cfq_cfqq_class_sync(cfqq) && |
22e2c507 JA |
1007 | time_before(now, cfqq->slice_end)) { |
1008 | if (cfq_arm_slice_timer(cfqd, cfqq)) | |
1009 | return NULL; | |
1010 | } | |
1011 | ||
3b18152c | 1012 | expire: |
22e2c507 | 1013 | cfq_slice_expired(cfqd, 0); |
3b18152c JA |
1014 | new_queue: |
1015 | cfqq = cfq_set_active_queue(cfqd); | |
22e2c507 | 1016 | keep_queue: |
3b18152c | 1017 | return cfqq; |
22e2c507 JA |
1018 | } |
1019 | ||
1020 | static int | |
1021 | __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1022 | int max_dispatch) | |
1023 | { | |
1024 | int dispatched = 0; | |
1025 | ||
1026 | BUG_ON(RB_EMPTY(&cfqq->sort_list)); | |
1027 | ||
1028 | do { | |
1029 | struct cfq_rq *crq; | |
1da177e4 LT |
1030 | |
1031 | /* | |
22e2c507 | 1032 | * follow expired path, else get first next available |
1da177e4 | 1033 | */ |
22e2c507 JA |
1034 | if ((crq = cfq_check_fifo(cfqq)) == NULL) |
1035 | crq = cfqq->next_crq; | |
1036 | ||
1037 | /* | |
1038 | * finally, insert request into driver dispatch list | |
1039 | */ | |
b4878f24 | 1040 | cfq_dispatch_insert(cfqd->queue, crq); |
1da177e4 | 1041 | |
22e2c507 JA |
1042 | cfqd->dispatch_slice++; |
1043 | dispatched++; | |
1da177e4 | 1044 | |
22e2c507 JA |
1045 | if (!cfqd->active_cic) { |
1046 | atomic_inc(&crq->io_context->ioc->refcount); | |
1047 | cfqd->active_cic = crq->io_context; | |
1048 | } | |
1da177e4 | 1049 | |
22e2c507 JA |
1050 | if (RB_EMPTY(&cfqq->sort_list)) |
1051 | break; | |
1052 | ||
1053 | } while (dispatched < max_dispatch); | |
1054 | ||
1055 | /* | |
1056 | * if slice end isn't set yet, set it. if at least one request was | |
1057 | * sync, use the sync time slice value | |
1058 | */ | |
1059 | if (!cfqq->slice_end) | |
1060 | cfq_set_prio_slice(cfqd, cfqq); | |
1061 | ||
1062 | /* | |
1063 | * expire an async queue immediately if it has used up its slice. idle | |
1064 | * queue always expire after 1 dispatch round. | |
1065 | */ | |
1066 | if ((!cfq_cfqq_sync(cfqq) && | |
1067 | cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
1068 | cfq_class_idle(cfqq)) | |
1069 | cfq_slice_expired(cfqd, 0); | |
1070 | ||
1071 | return dispatched; | |
1072 | } | |
1073 | ||
1b5ed5e1 TH |
1074 | static int |
1075 | cfq_forced_dispatch_cfqqs(struct list_head *list) | |
1076 | { | |
1077 | int dispatched = 0; | |
1078 | struct cfq_queue *cfqq, *next; | |
1079 | struct cfq_rq *crq; | |
1080 | ||
1081 | list_for_each_entry_safe(cfqq, next, list, cfq_list) { | |
1082 | while ((crq = cfqq->next_crq)) { | |
1083 | cfq_dispatch_insert(cfqq->cfqd->queue, crq); | |
1084 | dispatched++; | |
1085 | } | |
1086 | BUG_ON(!list_empty(&cfqq->fifo)); | |
1087 | } | |
1088 | return dispatched; | |
1089 | } | |
1090 | ||
1091 | static int | |
1092 | cfq_forced_dispatch(struct cfq_data *cfqd) | |
1093 | { | |
1094 | int i, dispatched = 0; | |
1095 | ||
1096 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
1097 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]); | |
1098 | ||
1099 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr); | |
1100 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr); | |
1101 | dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr); | |
1102 | ||
1103 | cfq_slice_expired(cfqd, 0); | |
1104 | ||
1105 | BUG_ON(cfqd->busy_queues); | |
1106 | ||
1107 | return dispatched; | |
1108 | } | |
1109 | ||
22e2c507 | 1110 | static int |
b4878f24 | 1111 | cfq_dispatch_requests(request_queue_t *q, int force) |
22e2c507 JA |
1112 | { |
1113 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1114 | struct cfq_queue *cfqq; | |
1115 | ||
1116 | if (!cfqd->busy_queues) | |
1117 | return 0; | |
1118 | ||
1b5ed5e1 TH |
1119 | if (unlikely(force)) |
1120 | return cfq_forced_dispatch(cfqd); | |
1121 | ||
1122 | cfqq = cfq_select_queue(cfqd); | |
22e2c507 | 1123 | if (cfqq) { |
b4878f24 JA |
1124 | int max_dispatch; |
1125 | ||
1126 | /* | |
1127 | * if idle window is disabled, allow queue buildup | |
1128 | */ | |
1129 | if (!cfq_cfqq_idle_window(cfqq) && | |
1130 | cfqd->rq_in_driver >= cfqd->cfq_max_depth) | |
1131 | return 0; | |
1132 | ||
3b18152c JA |
1133 | cfq_clear_cfqq_must_dispatch(cfqq); |
1134 | cfq_clear_cfqq_wait_request(cfqq); | |
22e2c507 JA |
1135 | del_timer(&cfqd->idle_slice_timer); |
1136 | ||
1b5ed5e1 TH |
1137 | max_dispatch = cfqd->cfq_quantum; |
1138 | if (cfq_class_idle(cfqq)) | |
1139 | max_dispatch = 1; | |
1da177e4 | 1140 | |
22e2c507 | 1141 | return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
1da177e4 LT |
1142 | } |
1143 | ||
22e2c507 | 1144 | return 0; |
1da177e4 LT |
1145 | } |
1146 | ||
1da177e4 LT |
1147 | /* |
1148 | * task holds one reference to the queue, dropped when task exits. each crq | |
1149 | * in-flight on this queue also holds a reference, dropped when crq is freed. | |
1150 | * | |
1151 | * queue lock must be held here. | |
1152 | */ | |
1153 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
1154 | { | |
22e2c507 JA |
1155 | struct cfq_data *cfqd = cfqq->cfqd; |
1156 | ||
1157 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
1158 | |
1159 | if (!atomic_dec_and_test(&cfqq->ref)) | |
1160 | return; | |
1161 | ||
1162 | BUG_ON(rb_first(&cfqq->sort_list)); | |
22e2c507 | 1163 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3b18152c | 1164 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 1165 | |
7b14e3b5 | 1166 | if (unlikely(cfqd->active_queue == cfqq)) |
3b18152c | 1167 | __cfq_slice_expired(cfqd, cfqq, 0); |
22e2c507 | 1168 | |
1da177e4 LT |
1169 | /* |
1170 | * it's on the empty list and still hashed | |
1171 | */ | |
1172 | list_del(&cfqq->cfq_list); | |
1173 | hlist_del(&cfqq->cfq_hash); | |
1174 | kmem_cache_free(cfq_pool, cfqq); | |
1175 | } | |
1176 | ||
1177 | static inline struct cfq_queue * | |
3b18152c JA |
1178 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, |
1179 | const int hashval) | |
1da177e4 LT |
1180 | { |
1181 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; | |
1182 | struct hlist_node *entry, *next; | |
1183 | ||
1184 | hlist_for_each_safe(entry, next, hash_list) { | |
1185 | struct cfq_queue *__cfqq = list_entry_qhash(entry); | |
b0a6916b | 1186 | const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio); |
1da177e4 | 1187 | |
3b18152c | 1188 | if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY)) |
1da177e4 LT |
1189 | return __cfqq; |
1190 | } | |
1191 | ||
1192 | return NULL; | |
1193 | } | |
1194 | ||
1195 | static struct cfq_queue * | |
3b18152c | 1196 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) |
1da177e4 | 1197 | { |
3b18152c | 1198 | return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); |
1da177e4 LT |
1199 | } |
1200 | ||
22e2c507 | 1201 | static void cfq_free_io_context(struct cfq_io_context *cic) |
1da177e4 | 1202 | { |
22e2c507 JA |
1203 | struct cfq_io_context *__cic; |
1204 | struct list_head *entry, *next; | |
334e94de | 1205 | int freed = 1; |
1da177e4 | 1206 | |
22e2c507 JA |
1207 | list_for_each_safe(entry, next, &cic->list) { |
1208 | __cic = list_entry(entry, struct cfq_io_context, list); | |
1209 | kmem_cache_free(cfq_ioc_pool, __cic); | |
334e94de | 1210 | freed++; |
1da177e4 LT |
1211 | } |
1212 | ||
22e2c507 | 1213 | kmem_cache_free(cfq_ioc_pool, cic); |
334e94de AV |
1214 | if (atomic_sub_and_test(freed, &ioc_count) && ioc_gone) |
1215 | complete(ioc_gone); | |
1da177e4 LT |
1216 | } |
1217 | ||
e17a9489 AV |
1218 | static void cfq_trim(struct io_context *ioc) |
1219 | { | |
1220 | ioc->set_ioprio = NULL; | |
1221 | if (ioc->cic) | |
1222 | cfq_free_io_context(ioc->cic); | |
1223 | } | |
1224 | ||
22e2c507 JA |
1225 | /* |
1226 | * Called with interrupts disabled | |
1227 | */ | |
1228 | static void cfq_exit_single_io_context(struct cfq_io_context *cic) | |
1da177e4 | 1229 | { |
478a82b0 | 1230 | struct cfq_data *cfqd = cic->key; |
d9ff4187 AV |
1231 | request_queue_t *q; |
1232 | ||
1233 | if (!cfqd) | |
1234 | return; | |
1235 | ||
1236 | q = cfqd->queue; | |
22e2c507 JA |
1237 | |
1238 | WARN_ON(!irqs_disabled()); | |
1239 | ||
1240 | spin_lock(q->queue_lock); | |
1241 | ||
12a05732 AV |
1242 | if (cic->cfqq[ASYNC]) { |
1243 | if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue)) | |
1244 | __cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0); | |
1245 | cfq_put_queue(cic->cfqq[ASYNC]); | |
1246 | cic->cfqq[ASYNC] = NULL; | |
1247 | } | |
1248 | ||
1249 | if (cic->cfqq[SYNC]) { | |
1250 | if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue)) | |
1251 | __cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0); | |
1252 | cfq_put_queue(cic->cfqq[SYNC]); | |
1253 | cic->cfqq[SYNC] = NULL; | |
1254 | } | |
22e2c507 | 1255 | |
478a82b0 | 1256 | cic->key = NULL; |
d9ff4187 | 1257 | list_del_init(&cic->queue_list); |
22e2c507 | 1258 | spin_unlock(q->queue_lock); |
1da177e4 LT |
1259 | } |
1260 | ||
1261 | /* | |
22e2c507 JA |
1262 | * Another task may update the task cic list, if it is doing a queue lookup |
1263 | * on its behalf. cfq_cic_lock excludes such concurrent updates | |
1da177e4 LT |
1264 | */ |
1265 | static void cfq_exit_io_context(struct cfq_io_context *cic) | |
1266 | { | |
22e2c507 JA |
1267 | struct cfq_io_context *__cic; |
1268 | struct list_head *entry; | |
1da177e4 LT |
1269 | unsigned long flags; |
1270 | ||
22e2c507 JA |
1271 | local_irq_save(flags); |
1272 | ||
1da177e4 LT |
1273 | /* |
1274 | * put the reference this task is holding to the various queues | |
1275 | */ | |
d9ff4187 | 1276 | read_lock(&cfq_exit_lock); |
22e2c507 | 1277 | list_for_each(entry, &cic->list) { |
1da177e4 | 1278 | __cic = list_entry(entry, struct cfq_io_context, list); |
22e2c507 | 1279 | cfq_exit_single_io_context(__cic); |
1da177e4 LT |
1280 | } |
1281 | ||
22e2c507 | 1282 | cfq_exit_single_io_context(cic); |
d9ff4187 | 1283 | read_unlock(&cfq_exit_lock); |
22e2c507 | 1284 | local_irq_restore(flags); |
1da177e4 LT |
1285 | } |
1286 | ||
22e2c507 | 1287 | static struct cfq_io_context * |
8267e268 | 1288 | cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4 | 1289 | { |
22e2c507 | 1290 | struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); |
1da177e4 LT |
1291 | |
1292 | if (cic) { | |
1da177e4 | 1293 | INIT_LIST_HEAD(&cic->list); |
12a05732 AV |
1294 | cic->cfqq[ASYNC] = NULL; |
1295 | cic->cfqq[SYNC] = NULL; | |
22e2c507 JA |
1296 | cic->key = NULL; |
1297 | cic->last_end_request = jiffies; | |
1298 | cic->ttime_total = 0; | |
1299 | cic->ttime_samples = 0; | |
1300 | cic->ttime_mean = 0; | |
1301 | cic->dtor = cfq_free_io_context; | |
1302 | cic->exit = cfq_exit_io_context; | |
d9ff4187 | 1303 | INIT_LIST_HEAD(&cic->queue_list); |
334e94de | 1304 | atomic_inc(&ioc_count); |
1da177e4 LT |
1305 | } |
1306 | ||
1307 | return cic; | |
1308 | } | |
1309 | ||
22e2c507 JA |
1310 | static void cfq_init_prio_data(struct cfq_queue *cfqq) |
1311 | { | |
1312 | struct task_struct *tsk = current; | |
1313 | int ioprio_class; | |
1314 | ||
3b18152c | 1315 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
1316 | return; |
1317 | ||
1318 | ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); | |
1319 | switch (ioprio_class) { | |
1320 | default: | |
1321 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
1322 | case IOPRIO_CLASS_NONE: | |
1323 | /* | |
1324 | * no prio set, place us in the middle of the BE classes | |
1325 | */ | |
1326 | cfqq->ioprio = task_nice_ioprio(tsk); | |
1327 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1328 | break; | |
1329 | case IOPRIO_CLASS_RT: | |
1330 | cfqq->ioprio = task_ioprio(tsk); | |
1331 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
1332 | break; | |
1333 | case IOPRIO_CLASS_BE: | |
1334 | cfqq->ioprio = task_ioprio(tsk); | |
1335 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1336 | break; | |
1337 | case IOPRIO_CLASS_IDLE: | |
1338 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
1339 | cfqq->ioprio = 7; | |
3b18152c | 1340 | cfq_clear_cfqq_idle_window(cfqq); |
22e2c507 JA |
1341 | break; |
1342 | } | |
1343 | ||
1344 | /* | |
1345 | * keep track of original prio settings in case we have to temporarily | |
1346 | * elevate the priority of this queue | |
1347 | */ | |
1348 | cfqq->org_ioprio = cfqq->ioprio; | |
1349 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
1350 | ||
3b18152c | 1351 | if (cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1352 | cfq_resort_rr_list(cfqq, 0); |
1353 | ||
3b18152c | 1354 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
1355 | } |
1356 | ||
478a82b0 | 1357 | static inline void changed_ioprio(struct cfq_io_context *cic) |
22e2c507 | 1358 | { |
478a82b0 AV |
1359 | struct cfq_data *cfqd = cic->key; |
1360 | struct cfq_queue *cfqq; | |
1361 | if (cfqd) { | |
22e2c507 | 1362 | spin_lock(cfqd->queue->queue_lock); |
12a05732 AV |
1363 | cfqq = cic->cfqq[ASYNC]; |
1364 | if (cfqq) { | |
6f325a13 AV |
1365 | struct cfq_queue *new_cfqq; |
1366 | new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, | |
1367 | cic->ioc->task, GFP_ATOMIC); | |
1368 | if (new_cfqq) { | |
1369 | cic->cfqq[ASYNC] = new_cfqq; | |
1370 | cfq_put_queue(cfqq); | |
1371 | } | |
12a05732 AV |
1372 | } |
1373 | cfqq = cic->cfqq[SYNC]; | |
478a82b0 AV |
1374 | if (cfqq) { |
1375 | cfq_mark_cfqq_prio_changed(cfqq); | |
1376 | cfq_init_prio_data(cfqq); | |
1377 | } | |
22e2c507 JA |
1378 | spin_unlock(cfqd->queue->queue_lock); |
1379 | } | |
1380 | } | |
1381 | ||
1382 | /* | |
1383 | * callback from sys_ioprio_set, irqs are disabled | |
1384 | */ | |
1385 | static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) | |
1386 | { | |
a6a0763a AV |
1387 | struct cfq_io_context *cic; |
1388 | ||
1389 | write_lock(&cfq_exit_lock); | |
1390 | ||
1391 | cic = ioc->cic; | |
22e2c507 | 1392 | |
478a82b0 | 1393 | changed_ioprio(cic); |
22e2c507 JA |
1394 | |
1395 | list_for_each_entry(cic, &cic->list, list) | |
478a82b0 | 1396 | changed_ioprio(cic); |
22e2c507 | 1397 | |
a6a0763a AV |
1398 | write_unlock(&cfq_exit_lock); |
1399 | ||
22e2c507 JA |
1400 | return 0; |
1401 | } | |
1402 | ||
1403 | static struct cfq_queue * | |
6f325a13 | 1404 | cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, |
8267e268 | 1405 | gfp_t gfp_mask) |
22e2c507 JA |
1406 | { |
1407 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); | |
1408 | struct cfq_queue *cfqq, *new_cfqq = NULL; | |
6f325a13 | 1409 | unsigned short ioprio; |
22e2c507 JA |
1410 | |
1411 | retry: | |
6f325a13 | 1412 | ioprio = tsk->ioprio; |
3b18152c | 1413 | cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); |
22e2c507 JA |
1414 | |
1415 | if (!cfqq) { | |
1416 | if (new_cfqq) { | |
1417 | cfqq = new_cfqq; | |
1418 | new_cfqq = NULL; | |
1419 | } else if (gfp_mask & __GFP_WAIT) { | |
1420 | spin_unlock_irq(cfqd->queue->queue_lock); | |
1421 | new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1422 | spin_lock_irq(cfqd->queue->queue_lock); | |
1423 | goto retry; | |
1424 | } else { | |
1425 | cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1426 | if (!cfqq) | |
1427 | goto out; | |
1428 | } | |
1429 | ||
1430 | memset(cfqq, 0, sizeof(*cfqq)); | |
1431 | ||
1432 | INIT_HLIST_NODE(&cfqq->cfq_hash); | |
1433 | INIT_LIST_HEAD(&cfqq->cfq_list); | |
1434 | RB_CLEAR_ROOT(&cfqq->sort_list); | |
1435 | INIT_LIST_HEAD(&cfqq->fifo); | |
1436 | ||
1437 | cfqq->key = key; | |
1438 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); | |
1439 | atomic_set(&cfqq->ref, 0); | |
1440 | cfqq->cfqd = cfqd; | |
22e2c507 JA |
1441 | cfqq->service_last = 0; |
1442 | /* | |
1443 | * set ->slice_left to allow preemption for a new process | |
1444 | */ | |
1445 | cfqq->slice_left = 2 * cfqd->cfq_slice_idle; | |
3b18152c JA |
1446 | cfq_mark_cfqq_idle_window(cfqq); |
1447 | cfq_mark_cfqq_prio_changed(cfqq); | |
1448 | cfq_init_prio_data(cfqq); | |
22e2c507 JA |
1449 | } |
1450 | ||
1451 | if (new_cfqq) | |
1452 | kmem_cache_free(cfq_pool, new_cfqq); | |
1453 | ||
1454 | atomic_inc(&cfqq->ref); | |
1455 | out: | |
1456 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); | |
1457 | return cfqq; | |
1458 | } | |
1459 | ||
1da177e4 LT |
1460 | /* |
1461 | * Setup general io context and cfq io context. There can be several cfq | |
1462 | * io contexts per general io context, if this process is doing io to more | |
1463 | * than one device managed by cfq. Note that caller is holding a reference to | |
1464 | * cfqq, so we don't need to worry about it disappearing | |
1465 | */ | |
1466 | static struct cfq_io_context * | |
8267e268 | 1467 | cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, gfp_t gfp_mask) |
1da177e4 | 1468 | { |
22e2c507 | 1469 | struct io_context *ioc = NULL; |
1da177e4 | 1470 | struct cfq_io_context *cic; |
1da177e4 | 1471 | |
22e2c507 | 1472 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 1473 | |
22e2c507 | 1474 | ioc = get_io_context(gfp_mask); |
1da177e4 LT |
1475 | if (!ioc) |
1476 | return NULL; | |
1477 | ||
d9ff4187 | 1478 | restart: |
1da177e4 | 1479 | if ((cic = ioc->cic) == NULL) { |
22e2c507 | 1480 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4 LT |
1481 | |
1482 | if (cic == NULL) | |
1483 | goto err; | |
1484 | ||
22e2c507 JA |
1485 | /* |
1486 | * manually increment generic io_context usage count, it | |
1487 | * cannot go away since we are already holding one ref to it | |
1488 | */ | |
1da177e4 | 1489 | cic->ioc = ioc; |
22e2c507 | 1490 | cic->key = cfqd; |
a6a0763a | 1491 | read_lock(&cfq_exit_lock); |
478a82b0 AV |
1492 | ioc->set_ioprio = cfq_ioc_set_ioprio; |
1493 | ioc->cic = cic; | |
d9ff4187 | 1494 | list_add(&cic->queue_list, &cfqd->cic_list); |
a6a0763a | 1495 | read_unlock(&cfq_exit_lock); |
1da177e4 LT |
1496 | } else { |
1497 | struct cfq_io_context *__cic; | |
1da177e4 LT |
1498 | |
1499 | /* | |
22e2c507 | 1500 | * the first cic on the list is actually the head itself |
1da177e4 | 1501 | */ |
22e2c507 | 1502 | if (cic->key == cfqd) |
1da177e4 LT |
1503 | goto out; |
1504 | ||
d9ff4187 AV |
1505 | if (unlikely(!cic->key)) { |
1506 | read_lock(&cfq_exit_lock); | |
1507 | if (list_empty(&cic->list)) | |
1508 | ioc->cic = NULL; | |
1509 | else | |
1510 | ioc->cic = list_entry(cic->list.next, | |
1511 | struct cfq_io_context, | |
1512 | list); | |
1513 | read_unlock(&cfq_exit_lock); | |
1514 | kmem_cache_free(cfq_ioc_pool, cic); | |
334e94de | 1515 | atomic_dec(&ioc_count); |
d9ff4187 AV |
1516 | goto restart; |
1517 | } | |
1518 | ||
1da177e4 LT |
1519 | /* |
1520 | * cic exists, check if we already are there. linear search | |
1521 | * should be ok here, the list will usually not be more than | |
1522 | * 1 or a few entries long | |
1523 | */ | |
1da177e4 LT |
1524 | list_for_each_entry(__cic, &cic->list, list) { |
1525 | /* | |
1526 | * this process is already holding a reference to | |
1527 | * this queue, so no need to get one more | |
1528 | */ | |
22e2c507 | 1529 | if (__cic->key == cfqd) { |
1da177e4 | 1530 | cic = __cic; |
1da177e4 LT |
1531 | goto out; |
1532 | } | |
d9ff4187 AV |
1533 | if (unlikely(!__cic->key)) { |
1534 | read_lock(&cfq_exit_lock); | |
1535 | list_del(&__cic->list); | |
1536 | read_unlock(&cfq_exit_lock); | |
1537 | kmem_cache_free(cfq_ioc_pool, __cic); | |
334e94de | 1538 | atomic_dec(&ioc_count); |
d9ff4187 AV |
1539 | goto restart; |
1540 | } | |
1da177e4 | 1541 | } |
1da177e4 LT |
1542 | |
1543 | /* | |
1544 | * nope, process doesn't have a cic assoicated with this | |
1545 | * cfqq yet. get a new one and add to list | |
1546 | */ | |
22e2c507 | 1547 | __cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4 LT |
1548 | if (__cic == NULL) |
1549 | goto err; | |
1550 | ||
1551 | __cic->ioc = ioc; | |
22e2c507 | 1552 | __cic->key = cfqd; |
a6a0763a | 1553 | read_lock(&cfq_exit_lock); |
1da177e4 | 1554 | list_add(&__cic->list, &cic->list); |
d9ff4187 | 1555 | list_add(&__cic->queue_list, &cfqd->cic_list); |
a6a0763a | 1556 | read_unlock(&cfq_exit_lock); |
1da177e4 | 1557 | cic = __cic; |
1da177e4 LT |
1558 | } |
1559 | ||
1560 | out: | |
1da177e4 LT |
1561 | return cic; |
1562 | err: | |
1563 | put_io_context(ioc); | |
1564 | return NULL; | |
1565 | } | |
1566 | ||
22e2c507 JA |
1567 | static void |
1568 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 1569 | { |
22e2c507 | 1570 | unsigned long elapsed, ttime; |
1da177e4 | 1571 | |
22e2c507 JA |
1572 | /* |
1573 | * if this context already has stuff queued, thinktime is from | |
1574 | * last queue not last end | |
1575 | */ | |
1576 | #if 0 | |
1577 | if (time_after(cic->last_end_request, cic->last_queue)) | |
1578 | elapsed = jiffies - cic->last_end_request; | |
1579 | else | |
1580 | elapsed = jiffies - cic->last_queue; | |
1581 | #else | |
1582 | elapsed = jiffies - cic->last_end_request; | |
1583 | #endif | |
1da177e4 | 1584 | |
22e2c507 | 1585 | ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
db3b5848 | 1586 | |
22e2c507 JA |
1587 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
1588 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
1589 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
1590 | } | |
1da177e4 | 1591 | |
22e2c507 | 1592 | #define sample_valid(samples) ((samples) > 80) |
1da177e4 | 1593 | |
22e2c507 JA |
1594 | /* |
1595 | * Disable idle window if the process thinks too long or seeks so much that | |
1596 | * it doesn't matter | |
1597 | */ | |
1598 | static void | |
1599 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1600 | struct cfq_io_context *cic) | |
1601 | { | |
3b18152c | 1602 | int enable_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 1603 | |
22e2c507 JA |
1604 | if (!cic->ioc->task || !cfqd->cfq_slice_idle) |
1605 | enable_idle = 0; | |
1606 | else if (sample_valid(cic->ttime_samples)) { | |
1607 | if (cic->ttime_mean > cfqd->cfq_slice_idle) | |
1608 | enable_idle = 0; | |
1609 | else | |
1610 | enable_idle = 1; | |
1da177e4 LT |
1611 | } |
1612 | ||
3b18152c JA |
1613 | if (enable_idle) |
1614 | cfq_mark_cfqq_idle_window(cfqq); | |
1615 | else | |
1616 | cfq_clear_cfqq_idle_window(cfqq); | |
22e2c507 | 1617 | } |
1da177e4 | 1618 | |
22e2c507 JA |
1619 | |
1620 | /* | |
1621 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
1622 | * no or if we aren't sure, a 1 will cause a preempt. | |
1623 | */ | |
1624 | static int | |
1625 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, | |
1626 | struct cfq_rq *crq) | |
1627 | { | |
1628 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1629 | ||
1630 | if (cfq_class_idle(new_cfqq)) | |
1631 | return 0; | |
1632 | ||
1633 | if (!cfqq) | |
1634 | return 1; | |
1635 | ||
1636 | if (cfq_class_idle(cfqq)) | |
1637 | return 1; | |
3b18152c | 1638 | if (!cfq_cfqq_wait_request(new_cfqq)) |
22e2c507 JA |
1639 | return 0; |
1640 | /* | |
1641 | * if it doesn't have slice left, forget it | |
1642 | */ | |
1643 | if (new_cfqq->slice_left < cfqd->cfq_slice_idle) | |
1644 | return 0; | |
3b18152c | 1645 | if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq)) |
22e2c507 JA |
1646 | return 1; |
1647 | ||
1648 | return 0; | |
1649 | } | |
1650 | ||
1651 | /* | |
1652 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
1653 | * let it have half of its nominal slice. | |
1654 | */ | |
1655 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1656 | { | |
1657 | struct cfq_queue *__cfqq, *next; | |
1658 | ||
1659 | list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) | |
1660 | cfq_resort_rr_list(__cfqq, 1); | |
1661 | ||
1662 | if (!cfqq->slice_left) | |
1663 | cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; | |
1664 | ||
1665 | cfqq->slice_end = cfqq->slice_left + jiffies; | |
3b18152c | 1666 | __cfq_slice_expired(cfqd, cfqq, 1); |
22e2c507 JA |
1667 | __cfq_set_active_queue(cfqd, cfqq); |
1668 | } | |
1669 | ||
1670 | /* | |
1671 | * should really be a ll_rw_blk.c helper | |
1672 | */ | |
1673 | static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1674 | { | |
1675 | request_queue_t *q = cfqd->queue; | |
1676 | ||
1677 | if (!blk_queue_plugged(q)) | |
1678 | q->request_fn(q); | |
1679 | else | |
1680 | __generic_unplug_device(q); | |
1681 | } | |
1682 | ||
1683 | /* | |
1684 | * Called when a new fs request (crq) is added (to cfqq). Check if there's | |
1685 | * something we should do about it | |
1686 | */ | |
1687 | static void | |
1688 | cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1689 | struct cfq_rq *crq) | |
1690 | { | |
9c2c38a1 | 1691 | struct cfq_io_context *cic; |
22e2c507 JA |
1692 | |
1693 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
1694 | ||
9c2c38a1 JA |
1695 | /* |
1696 | * we never wait for an async request and we don't allow preemption | |
1697 | * of an async request. so just return early | |
1698 | */ | |
1699 | if (!cfq_crq_is_sync(crq)) | |
1700 | return; | |
22e2c507 | 1701 | |
9c2c38a1 | 1702 | cic = crq->io_context; |
22e2c507 | 1703 | |
9c2c38a1 JA |
1704 | cfq_update_io_thinktime(cfqd, cic); |
1705 | cfq_update_idle_window(cfqd, cfqq, cic); | |
1706 | ||
1707 | cic->last_queue = jiffies; | |
22e2c507 JA |
1708 | |
1709 | if (cfqq == cfqd->active_queue) { | |
1710 | /* | |
1711 | * if we are waiting for a request for this queue, let it rip | |
1712 | * immediately and flag that we must not expire this queue | |
1713 | * just now | |
1714 | */ | |
3b18152c JA |
1715 | if (cfq_cfqq_wait_request(cfqq)) { |
1716 | cfq_mark_cfqq_must_dispatch(cfqq); | |
22e2c507 JA |
1717 | del_timer(&cfqd->idle_slice_timer); |
1718 | cfq_start_queueing(cfqd, cfqq); | |
1719 | } | |
1720 | } else if (cfq_should_preempt(cfqd, cfqq, crq)) { | |
1721 | /* | |
1722 | * not the active queue - expire current slice if it is | |
1723 | * idle and has expired it's mean thinktime or this new queue | |
1724 | * has some old slice time left and is of higher priority | |
1725 | */ | |
1726 | cfq_preempt_queue(cfqd, cfqq); | |
3b18152c | 1727 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
1728 | cfq_start_queueing(cfqd, cfqq); |
1729 | } | |
1da177e4 LT |
1730 | } |
1731 | ||
b4878f24 | 1732 | static void cfq_insert_request(request_queue_t *q, struct request *rq) |
1da177e4 | 1733 | { |
b4878f24 | 1734 | struct cfq_data *cfqd = q->elevator->elevator_data; |
22e2c507 JA |
1735 | struct cfq_rq *crq = RQ_DATA(rq); |
1736 | struct cfq_queue *cfqq = crq->cfq_queue; | |
1737 | ||
1738 | cfq_init_prio_data(cfqq); | |
1da177e4 LT |
1739 | |
1740 | cfq_add_crq_rb(crq); | |
1da177e4 | 1741 | |
22e2c507 JA |
1742 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
1743 | ||
98b11471 | 1744 | if (rq_mergeable(rq)) |
22e2c507 JA |
1745 | cfq_add_crq_hash(cfqd, crq); |
1746 | ||
22e2c507 | 1747 | cfq_crq_enqueued(cfqd, cfqq, crq); |
1da177e4 LT |
1748 | } |
1749 | ||
1da177e4 LT |
1750 | static void cfq_completed_request(request_queue_t *q, struct request *rq) |
1751 | { | |
1752 | struct cfq_rq *crq = RQ_DATA(rq); | |
b4878f24 JA |
1753 | struct cfq_queue *cfqq = crq->cfq_queue; |
1754 | struct cfq_data *cfqd = cfqq->cfqd; | |
1755 | const int sync = cfq_crq_is_sync(crq); | |
1756 | unsigned long now; | |
1da177e4 | 1757 | |
b4878f24 | 1758 | now = jiffies; |
1da177e4 | 1759 | |
b4878f24 JA |
1760 | WARN_ON(!cfqd->rq_in_driver); |
1761 | WARN_ON(!cfqq->on_dispatch[sync]); | |
1762 | cfqd->rq_in_driver--; | |
1763 | cfqq->on_dispatch[sync]--; | |
1da177e4 | 1764 | |
b4878f24 JA |
1765 | if (!cfq_class_idle(cfqq)) |
1766 | cfqd->last_end_request = now; | |
3b18152c | 1767 | |
b4878f24 JA |
1768 | if (!cfq_cfqq_dispatched(cfqq)) { |
1769 | if (cfq_cfqq_on_rr(cfqq)) { | |
1770 | cfqq->service_last = now; | |
1771 | cfq_resort_rr_list(cfqq, 0); | |
1772 | } | |
7b14e3b5 | 1773 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
1774 | } |
1775 | ||
b4878f24 JA |
1776 | if (cfq_crq_is_sync(crq)) |
1777 | crq->io_context->last_end_request = now; | |
1da177e4 LT |
1778 | } |
1779 | ||
1780 | static struct request * | |
1781 | cfq_former_request(request_queue_t *q, struct request *rq) | |
1782 | { | |
1783 | struct cfq_rq *crq = RQ_DATA(rq); | |
1784 | struct rb_node *rbprev = rb_prev(&crq->rb_node); | |
1785 | ||
1786 | if (rbprev) | |
1787 | return rb_entry_crq(rbprev)->request; | |
1788 | ||
1789 | return NULL; | |
1790 | } | |
1791 | ||
1792 | static struct request * | |
1793 | cfq_latter_request(request_queue_t *q, struct request *rq) | |
1794 | { | |
1795 | struct cfq_rq *crq = RQ_DATA(rq); | |
1796 | struct rb_node *rbnext = rb_next(&crq->rb_node); | |
1797 | ||
1798 | if (rbnext) | |
1799 | return rb_entry_crq(rbnext)->request; | |
1800 | ||
1801 | return NULL; | |
1802 | } | |
1803 | ||
22e2c507 JA |
1804 | /* |
1805 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
1806 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
1807 | */ | |
1808 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 1809 | { |
22e2c507 JA |
1810 | const int ioprio_class = cfqq->ioprio_class; |
1811 | const int ioprio = cfqq->ioprio; | |
1da177e4 | 1812 | |
22e2c507 JA |
1813 | if (has_fs_excl()) { |
1814 | /* | |
1815 | * boost idle prio on transactions that would lock out other | |
1816 | * users of the filesystem | |
1817 | */ | |
1818 | if (cfq_class_idle(cfqq)) | |
1819 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1820 | if (cfqq->ioprio > IOPRIO_NORM) | |
1821 | cfqq->ioprio = IOPRIO_NORM; | |
1822 | } else { | |
1823 | /* | |
1824 | * check if we need to unboost the queue | |
1825 | */ | |
1826 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) | |
1827 | cfqq->ioprio_class = cfqq->org_ioprio_class; | |
1828 | if (cfqq->ioprio != cfqq->org_ioprio) | |
1829 | cfqq->ioprio = cfqq->org_ioprio; | |
1830 | } | |
1da177e4 | 1831 | |
22e2c507 JA |
1832 | /* |
1833 | * refile between round-robin lists if we moved the priority class | |
1834 | */ | |
1835 | if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && | |
3b18152c | 1836 | cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1837 | cfq_resort_rr_list(cfqq, 0); |
1838 | } | |
1da177e4 | 1839 | |
22e2c507 JA |
1840 | static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
1841 | { | |
1842 | if (rw == READ || process_sync(task)) | |
1843 | return task->pid; | |
1da177e4 | 1844 | |
22e2c507 JA |
1845 | return CFQ_KEY_ASYNC; |
1846 | } | |
1da177e4 | 1847 | |
22e2c507 JA |
1848 | static inline int |
1849 | __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1850 | struct task_struct *task, int rw) | |
1851 | { | |
3b18152c JA |
1852 | #if 1 |
1853 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && | |
99f95e52 | 1854 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1855 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1856 | return ELV_MQUEUE_MUST; |
3b18152c | 1857 | } |
1da177e4 | 1858 | |
22e2c507 | 1859 | return ELV_MQUEUE_MAY; |
3b18152c | 1860 | #else |
22e2c507 JA |
1861 | if (!cfqq || task->flags & PF_MEMALLOC) |
1862 | return ELV_MQUEUE_MAY; | |
3b18152c JA |
1863 | if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) { |
1864 | if (cfq_cfqq_wait_request(cfqq)) | |
22e2c507 | 1865 | return ELV_MQUEUE_MUST; |
1da177e4 | 1866 | |
22e2c507 JA |
1867 | /* |
1868 | * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we | |
1869 | * can quickly flood the queue with writes from a single task | |
1870 | */ | |
99f95e52 | 1871 | if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1872 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1873 | return ELV_MQUEUE_MUST; |
1da177e4 | 1874 | } |
22e2c507 JA |
1875 | |
1876 | return ELV_MQUEUE_MAY; | |
1da177e4 | 1877 | } |
22e2c507 JA |
1878 | if (cfq_class_idle(cfqq)) |
1879 | return ELV_MQUEUE_NO; | |
1880 | if (cfqq->allocated[rw] >= cfqd->max_queued) { | |
1881 | struct io_context *ioc = get_io_context(GFP_ATOMIC); | |
1882 | int ret = ELV_MQUEUE_NO; | |
1da177e4 | 1883 | |
22e2c507 JA |
1884 | if (ioc && ioc->nr_batch_requests) |
1885 | ret = ELV_MQUEUE_MAY; | |
1886 | ||
1887 | put_io_context(ioc); | |
1888 | return ret; | |
1889 | } | |
1890 | ||
1891 | return ELV_MQUEUE_MAY; | |
1892 | #endif | |
1893 | } | |
1894 | ||
1895 | static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) | |
1896 | { | |
1897 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1898 | struct task_struct *tsk = current; | |
1899 | struct cfq_queue *cfqq; | |
1900 | ||
1901 | /* | |
1902 | * don't force setup of a queue from here, as a call to may_queue | |
1903 | * does not necessarily imply that a request actually will be queued. | |
1904 | * so just lookup a possibly existing queue, or return 'may queue' | |
1905 | * if that fails | |
1906 | */ | |
3b18152c | 1907 | cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); |
22e2c507 JA |
1908 | if (cfqq) { |
1909 | cfq_init_prio_data(cfqq); | |
1910 | cfq_prio_boost(cfqq); | |
1911 | ||
1912 | return __cfq_may_queue(cfqd, cfqq, tsk, rw); | |
1913 | } | |
1914 | ||
1915 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
1916 | } |
1917 | ||
1918 | static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) | |
1919 | { | |
22e2c507 | 1920 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1da177e4 | 1921 | struct request_list *rl = &q->rq; |
1da177e4 | 1922 | |
22e2c507 JA |
1923 | if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) { |
1924 | smp_mb(); | |
1925 | if (waitqueue_active(&rl->wait[READ])) | |
1926 | wake_up(&rl->wait[READ]); | |
1927 | } | |
1928 | ||
1929 | if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) { | |
1930 | smp_mb(); | |
1931 | if (waitqueue_active(&rl->wait[WRITE])) | |
1932 | wake_up(&rl->wait[WRITE]); | |
1933 | } | |
1da177e4 LT |
1934 | } |
1935 | ||
1936 | /* | |
1937 | * queue lock held here | |
1938 | */ | |
1939 | static void cfq_put_request(request_queue_t *q, struct request *rq) | |
1940 | { | |
1941 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1942 | struct cfq_rq *crq = RQ_DATA(rq); | |
1943 | ||
1944 | if (crq) { | |
1945 | struct cfq_queue *cfqq = crq->cfq_queue; | |
22e2c507 | 1946 | const int rw = rq_data_dir(rq); |
1da177e4 | 1947 | |
22e2c507 JA |
1948 | BUG_ON(!cfqq->allocated[rw]); |
1949 | cfqq->allocated[rw]--; | |
1da177e4 | 1950 | |
22e2c507 | 1951 | put_io_context(crq->io_context->ioc); |
1da177e4 LT |
1952 | |
1953 | mempool_free(crq, cfqd->crq_pool); | |
1954 | rq->elevator_private = NULL; | |
1955 | ||
1da177e4 LT |
1956 | cfq_check_waiters(q, cfqq); |
1957 | cfq_put_queue(cfqq); | |
1958 | } | |
1959 | } | |
1960 | ||
1961 | /* | |
22e2c507 | 1962 | * Allocate cfq data structures associated with this request. |
1da177e4 | 1963 | */ |
22e2c507 JA |
1964 | static int |
1965 | cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, | |
8267e268 | 1966 | gfp_t gfp_mask) |
1da177e4 LT |
1967 | { |
1968 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3b18152c | 1969 | struct task_struct *tsk = current; |
1da177e4 LT |
1970 | struct cfq_io_context *cic; |
1971 | const int rw = rq_data_dir(rq); | |
3b18152c | 1972 | pid_t key = cfq_queue_pid(tsk, rw); |
22e2c507 | 1973 | struct cfq_queue *cfqq; |
1da177e4 LT |
1974 | struct cfq_rq *crq; |
1975 | unsigned long flags; | |
12a05732 | 1976 | int is_sync = key != CFQ_KEY_ASYNC; |
1da177e4 LT |
1977 | |
1978 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
1979 | ||
3b18152c | 1980 | cic = cfq_get_io_context(cfqd, key, gfp_mask); |
22e2c507 | 1981 | |
1da177e4 LT |
1982 | spin_lock_irqsave(q->queue_lock, flags); |
1983 | ||
22e2c507 JA |
1984 | if (!cic) |
1985 | goto queue_fail; | |
1986 | ||
12a05732 | 1987 | if (!cic->cfqq[is_sync]) { |
6f325a13 | 1988 | cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask); |
22e2c507 JA |
1989 | if (!cfqq) |
1990 | goto queue_fail; | |
1da177e4 | 1991 | |
12a05732 | 1992 | cic->cfqq[is_sync] = cfqq; |
22e2c507 | 1993 | } else |
12a05732 | 1994 | cfqq = cic->cfqq[is_sync]; |
1da177e4 LT |
1995 | |
1996 | cfqq->allocated[rw]++; | |
3b18152c | 1997 | cfq_clear_cfqq_must_alloc(cfqq); |
22e2c507 JA |
1998 | cfqd->rq_starved = 0; |
1999 | atomic_inc(&cfqq->ref); | |
1da177e4 LT |
2000 | spin_unlock_irqrestore(q->queue_lock, flags); |
2001 | ||
1da177e4 LT |
2002 | crq = mempool_alloc(cfqd->crq_pool, gfp_mask); |
2003 | if (crq) { | |
2004 | RB_CLEAR(&crq->rb_node); | |
2005 | crq->rb_key = 0; | |
2006 | crq->request = rq; | |
2007 | INIT_HLIST_NODE(&crq->hash); | |
2008 | crq->cfq_queue = cfqq; | |
2009 | crq->io_context = cic; | |
3b18152c | 2010 | |
12a05732 | 2011 | if (is_sync) |
3b18152c JA |
2012 | cfq_mark_crq_is_sync(crq); |
2013 | else | |
2014 | cfq_clear_crq_is_sync(crq); | |
2015 | ||
1da177e4 | 2016 | rq->elevator_private = crq; |
1da177e4 LT |
2017 | return 0; |
2018 | } | |
2019 | ||
1da177e4 LT |
2020 | spin_lock_irqsave(q->queue_lock, flags); |
2021 | cfqq->allocated[rw]--; | |
22e2c507 | 2022 | if (!(cfqq->allocated[0] + cfqq->allocated[1])) |
3b18152c | 2023 | cfq_mark_cfqq_must_alloc(cfqq); |
1da177e4 | 2024 | cfq_put_queue(cfqq); |
22e2c507 JA |
2025 | queue_fail: |
2026 | if (cic) | |
2027 | put_io_context(cic->ioc); | |
2028 | /* | |
2029 | * mark us rq allocation starved. we need to kickstart the process | |
2030 | * ourselves if there are no pending requests that can do it for us. | |
2031 | * that would be an extremely rare OOM situation | |
2032 | */ | |
2033 | cfqd->rq_starved = 1; | |
3b18152c | 2034 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
2035 | spin_unlock_irqrestore(q->queue_lock, flags); |
2036 | return 1; | |
2037 | } | |
2038 | ||
22e2c507 JA |
2039 | static void cfq_kick_queue(void *data) |
2040 | { | |
2041 | request_queue_t *q = data; | |
2042 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2043 | unsigned long flags; | |
2044 | ||
2045 | spin_lock_irqsave(q->queue_lock, flags); | |
2046 | ||
2047 | if (cfqd->rq_starved) { | |
2048 | struct request_list *rl = &q->rq; | |
2049 | ||
2050 | /* | |
2051 | * we aren't guaranteed to get a request after this, but we | |
2052 | * have to be opportunistic | |
2053 | */ | |
2054 | smp_mb(); | |
2055 | if (waitqueue_active(&rl->wait[READ])) | |
2056 | wake_up(&rl->wait[READ]); | |
2057 | if (waitqueue_active(&rl->wait[WRITE])) | |
2058 | wake_up(&rl->wait[WRITE]); | |
2059 | } | |
2060 | ||
2061 | blk_remove_plug(q); | |
2062 | q->request_fn(q); | |
2063 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2064 | } | |
2065 | ||
2066 | /* | |
2067 | * Timer running if the active_queue is currently idling inside its time slice | |
2068 | */ | |
2069 | static void cfq_idle_slice_timer(unsigned long data) | |
2070 | { | |
2071 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2072 | struct cfq_queue *cfqq; | |
2073 | unsigned long flags; | |
2074 | ||
2075 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2076 | ||
2077 | if ((cfqq = cfqd->active_queue) != NULL) { | |
2078 | unsigned long now = jiffies; | |
2079 | ||
2080 | /* | |
2081 | * expired | |
2082 | */ | |
2083 | if (time_after(now, cfqq->slice_end)) | |
2084 | goto expire; | |
2085 | ||
2086 | /* | |
2087 | * only expire and reinvoke request handler, if there are | |
2088 | * other queues with pending requests | |
2089 | */ | |
b4878f24 | 2090 | if (!cfqd->busy_queues) { |
22e2c507 JA |
2091 | cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end); |
2092 | add_timer(&cfqd->idle_slice_timer); | |
2093 | goto out_cont; | |
2094 | } | |
2095 | ||
2096 | /* | |
2097 | * not expired and it has a request pending, let it dispatch | |
2098 | */ | |
2099 | if (!RB_EMPTY(&cfqq->sort_list)) { | |
3b18152c | 2100 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
2101 | goto out_kick; |
2102 | } | |
2103 | } | |
2104 | expire: | |
2105 | cfq_slice_expired(cfqd, 0); | |
2106 | out_kick: | |
3b18152c | 2107 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2108 | out_cont: |
2109 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2110 | } | |
2111 | ||
2112 | /* | |
2113 | * Timer running if an idle class queue is waiting for service | |
2114 | */ | |
2115 | static void cfq_idle_class_timer(unsigned long data) | |
2116 | { | |
2117 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2118 | unsigned long flags, end; | |
2119 | ||
2120 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2121 | ||
2122 | /* | |
2123 | * race with a non-idle queue, reset timer | |
2124 | */ | |
2125 | end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
2126 | if (!time_after_eq(jiffies, end)) { | |
2127 | cfqd->idle_class_timer.expires = end; | |
2128 | add_timer(&cfqd->idle_class_timer); | |
2129 | } else | |
3b18152c | 2130 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2131 | |
2132 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2133 | } | |
2134 | ||
3b18152c JA |
2135 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
2136 | { | |
2137 | del_timer_sync(&cfqd->idle_slice_timer); | |
2138 | del_timer_sync(&cfqd->idle_class_timer); | |
2139 | blk_sync_queue(cfqd->queue); | |
2140 | } | |
22e2c507 | 2141 | |
1da177e4 LT |
2142 | static void cfq_exit_queue(elevator_t *e) |
2143 | { | |
22e2c507 | 2144 | struct cfq_data *cfqd = e->elevator_data; |
d9ff4187 | 2145 | request_queue_t *q = cfqd->queue; |
22e2c507 | 2146 | |
3b18152c | 2147 | cfq_shutdown_timer_wq(cfqd); |
d9ff4187 AV |
2148 | write_lock(&cfq_exit_lock); |
2149 | spin_lock_irq(q->queue_lock); | |
2150 | if (cfqd->active_queue) | |
2151 | __cfq_slice_expired(cfqd, cfqd->active_queue, 0); | |
2152 | while(!list_empty(&cfqd->cic_list)) { | |
2153 | struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, | |
2154 | struct cfq_io_context, | |
2155 | queue_list); | |
2156 | if (cic->cfqq[ASYNC]) { | |
2157 | cfq_put_queue(cic->cfqq[ASYNC]); | |
2158 | cic->cfqq[ASYNC] = NULL; | |
2159 | } | |
2160 | if (cic->cfqq[SYNC]) { | |
2161 | cfq_put_queue(cic->cfqq[SYNC]); | |
2162 | cic->cfqq[SYNC] = NULL; | |
2163 | } | |
2164 | cic->key = NULL; | |
2165 | list_del_init(&cic->queue_list); | |
2166 | } | |
2167 | spin_unlock_irq(q->queue_lock); | |
2168 | write_unlock(&cfq_exit_lock); | |
a90d742e AV |
2169 | |
2170 | cfq_shutdown_timer_wq(cfqd); | |
2171 | ||
2172 | mempool_destroy(cfqd->crq_pool); | |
2173 | kfree(cfqd->crq_hash); | |
2174 | kfree(cfqd->cfq_hash); | |
2175 | kfree(cfqd); | |
1da177e4 LT |
2176 | } |
2177 | ||
2178 | static int cfq_init_queue(request_queue_t *q, elevator_t *e) | |
2179 | { | |
2180 | struct cfq_data *cfqd; | |
2181 | int i; | |
2182 | ||
2183 | cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); | |
2184 | if (!cfqd) | |
2185 | return -ENOMEM; | |
2186 | ||
2187 | memset(cfqd, 0, sizeof(*cfqd)); | |
22e2c507 JA |
2188 | |
2189 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
2190 | INIT_LIST_HEAD(&cfqd->rr_list[i]); | |
2191 | ||
2192 | INIT_LIST_HEAD(&cfqd->busy_rr); | |
2193 | INIT_LIST_HEAD(&cfqd->cur_rr); | |
2194 | INIT_LIST_HEAD(&cfqd->idle_rr); | |
1da177e4 | 2195 | INIT_LIST_HEAD(&cfqd->empty_list); |
d9ff4187 | 2196 | INIT_LIST_HEAD(&cfqd->cic_list); |
1da177e4 LT |
2197 | |
2198 | cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); | |
2199 | if (!cfqd->crq_hash) | |
2200 | goto out_crqhash; | |
2201 | ||
2202 | cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); | |
2203 | if (!cfqd->cfq_hash) | |
2204 | goto out_cfqhash; | |
2205 | ||
2206 | cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool); | |
2207 | if (!cfqd->crq_pool) | |
2208 | goto out_crqpool; | |
2209 | ||
2210 | for (i = 0; i < CFQ_MHASH_ENTRIES; i++) | |
2211 | INIT_HLIST_HEAD(&cfqd->crq_hash[i]); | |
2212 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) | |
2213 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); | |
2214 | ||
2215 | e->elevator_data = cfqd; | |
2216 | ||
2217 | cfqd->queue = q; | |
1da177e4 | 2218 | |
22e2c507 | 2219 | cfqd->max_queued = q->nr_requests / 4; |
1da177e4 | 2220 | q->nr_batching = cfq_queued; |
22e2c507 JA |
2221 | |
2222 | init_timer(&cfqd->idle_slice_timer); | |
2223 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
2224 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
2225 | ||
2226 | init_timer(&cfqd->idle_class_timer); | |
2227 | cfqd->idle_class_timer.function = cfq_idle_class_timer; | |
2228 | cfqd->idle_class_timer.data = (unsigned long) cfqd; | |
2229 | ||
2230 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); | |
2231 | ||
1da177e4 LT |
2232 | cfqd->cfq_queued = cfq_queued; |
2233 | cfqd->cfq_quantum = cfq_quantum; | |
22e2c507 JA |
2234 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
2235 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
2236 | cfqd->cfq_back_max = cfq_back_max; |
2237 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
2238 | cfqd->cfq_slice[0] = cfq_slice_async; |
2239 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
2240 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
2241 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
2242 | cfqd->cfq_max_depth = cfq_max_depth; | |
3b18152c | 2243 | |
1da177e4 LT |
2244 | return 0; |
2245 | out_crqpool: | |
2246 | kfree(cfqd->cfq_hash); | |
2247 | out_cfqhash: | |
2248 | kfree(cfqd->crq_hash); | |
2249 | out_crqhash: | |
2250 | kfree(cfqd); | |
2251 | return -ENOMEM; | |
2252 | } | |
2253 | ||
2254 | static void cfq_slab_kill(void) | |
2255 | { | |
2256 | if (crq_pool) | |
2257 | kmem_cache_destroy(crq_pool); | |
2258 | if (cfq_pool) | |
2259 | kmem_cache_destroy(cfq_pool); | |
2260 | if (cfq_ioc_pool) | |
2261 | kmem_cache_destroy(cfq_ioc_pool); | |
2262 | } | |
2263 | ||
2264 | static int __init cfq_slab_setup(void) | |
2265 | { | |
2266 | crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, | |
2267 | NULL, NULL); | |
2268 | if (!crq_pool) | |
2269 | goto fail; | |
2270 | ||
2271 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, | |
2272 | NULL, NULL); | |
2273 | if (!cfq_pool) | |
2274 | goto fail; | |
2275 | ||
2276 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", | |
2277 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); | |
2278 | if (!cfq_ioc_pool) | |
2279 | goto fail; | |
2280 | ||
2281 | return 0; | |
2282 | fail: | |
2283 | cfq_slab_kill(); | |
2284 | return -ENOMEM; | |
2285 | } | |
2286 | ||
1da177e4 LT |
2287 | /* |
2288 | * sysfs parts below --> | |
2289 | */ | |
2290 | struct cfq_fs_entry { | |
2291 | struct attribute attr; | |
2292 | ssize_t (*show)(struct cfq_data *, char *); | |
2293 | ssize_t (*store)(struct cfq_data *, const char *, size_t); | |
2294 | }; | |
2295 | ||
2296 | static ssize_t | |
2297 | cfq_var_show(unsigned int var, char *page) | |
2298 | { | |
2299 | return sprintf(page, "%d\n", var); | |
2300 | } | |
2301 | ||
2302 | static ssize_t | |
2303 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
2304 | { | |
2305 | char *p = (char *) page; | |
2306 | ||
2307 | *var = simple_strtoul(p, &p, 10); | |
2308 | return count; | |
2309 | } | |
2310 | ||
1da177e4 LT |
2311 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
2312 | static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \ | |
2313 | { \ | |
2314 | unsigned int __data = __VAR; \ | |
2315 | if (__CONV) \ | |
2316 | __data = jiffies_to_msecs(__data); \ | |
2317 | return cfq_var_show(__data, (page)); \ | |
2318 | } | |
2319 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
2320 | SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); | |
22e2c507 JA |
2321 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
2322 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
1da177e4 LT |
2323 | SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); |
2324 | SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
2325 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
2326 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
2327 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
2328 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
2329 | SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0); | |
1da177e4 LT |
2330 | #undef SHOW_FUNCTION |
2331 | ||
2332 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
2333 | static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \ | |
2334 | { \ | |
2335 | unsigned int __data; \ | |
2336 | int ret = cfq_var_store(&__data, (page), count); \ | |
2337 | if (__data < (MIN)) \ | |
2338 | __data = (MIN); \ | |
2339 | else if (__data > (MAX)) \ | |
2340 | __data = (MAX); \ | |
2341 | if (__CONV) \ | |
2342 | *(__PTR) = msecs_to_jiffies(__data); \ | |
2343 | else \ | |
2344 | *(__PTR) = __data; \ | |
2345 | return ret; \ | |
2346 | } | |
2347 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
2348 | STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); | |
22e2c507 JA |
2349 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); |
2350 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); | |
1da177e4 LT |
2351 | STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
2352 | STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); | |
22e2c507 JA |
2353 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
2354 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
2355 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
2356 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); | |
2357 | STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0); | |
1da177e4 LT |
2358 | #undef STORE_FUNCTION |
2359 | ||
2360 | static struct cfq_fs_entry cfq_quantum_entry = { | |
2361 | .attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR }, | |
2362 | .show = cfq_quantum_show, | |
2363 | .store = cfq_quantum_store, | |
2364 | }; | |
2365 | static struct cfq_fs_entry cfq_queued_entry = { | |
2366 | .attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR }, | |
2367 | .show = cfq_queued_show, | |
2368 | .store = cfq_queued_store, | |
2369 | }; | |
22e2c507 | 2370 | static struct cfq_fs_entry cfq_fifo_expire_sync_entry = { |
1da177e4 | 2371 | .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, |
22e2c507 JA |
2372 | .show = cfq_fifo_expire_sync_show, |
2373 | .store = cfq_fifo_expire_sync_store, | |
1da177e4 | 2374 | }; |
22e2c507 | 2375 | static struct cfq_fs_entry cfq_fifo_expire_async_entry = { |
1da177e4 | 2376 | .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, |
22e2c507 JA |
2377 | .show = cfq_fifo_expire_async_show, |
2378 | .store = cfq_fifo_expire_async_store, | |
1da177e4 LT |
2379 | }; |
2380 | static struct cfq_fs_entry cfq_back_max_entry = { | |
2381 | .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR }, | |
2382 | .show = cfq_back_max_show, | |
2383 | .store = cfq_back_max_store, | |
2384 | }; | |
2385 | static struct cfq_fs_entry cfq_back_penalty_entry = { | |
2386 | .attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR }, | |
2387 | .show = cfq_back_penalty_show, | |
2388 | .store = cfq_back_penalty_store, | |
2389 | }; | |
22e2c507 JA |
2390 | static struct cfq_fs_entry cfq_slice_sync_entry = { |
2391 | .attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR }, | |
2392 | .show = cfq_slice_sync_show, | |
2393 | .store = cfq_slice_sync_store, | |
1da177e4 | 2394 | }; |
22e2c507 JA |
2395 | static struct cfq_fs_entry cfq_slice_async_entry = { |
2396 | .attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR }, | |
2397 | .show = cfq_slice_async_show, | |
2398 | .store = cfq_slice_async_store, | |
2399 | }; | |
2400 | static struct cfq_fs_entry cfq_slice_async_rq_entry = { | |
2401 | .attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR }, | |
2402 | .show = cfq_slice_async_rq_show, | |
2403 | .store = cfq_slice_async_rq_store, | |
2404 | }; | |
2405 | static struct cfq_fs_entry cfq_slice_idle_entry = { | |
2406 | .attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR }, | |
2407 | .show = cfq_slice_idle_show, | |
2408 | .store = cfq_slice_idle_store, | |
2409 | }; | |
2410 | static struct cfq_fs_entry cfq_max_depth_entry = { | |
2411 | .attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR }, | |
2412 | .show = cfq_max_depth_show, | |
2413 | .store = cfq_max_depth_store, | |
1da177e4 | 2414 | }; |
3b18152c | 2415 | |
1da177e4 LT |
2416 | static struct attribute *default_attrs[] = { |
2417 | &cfq_quantum_entry.attr, | |
2418 | &cfq_queued_entry.attr, | |
22e2c507 JA |
2419 | &cfq_fifo_expire_sync_entry.attr, |
2420 | &cfq_fifo_expire_async_entry.attr, | |
1da177e4 LT |
2421 | &cfq_back_max_entry.attr, |
2422 | &cfq_back_penalty_entry.attr, | |
22e2c507 JA |
2423 | &cfq_slice_sync_entry.attr, |
2424 | &cfq_slice_async_entry.attr, | |
2425 | &cfq_slice_async_rq_entry.attr, | |
2426 | &cfq_slice_idle_entry.attr, | |
2427 | &cfq_max_depth_entry.attr, | |
1da177e4 LT |
2428 | NULL, |
2429 | }; | |
2430 | ||
2431 | #define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr) | |
2432 | ||
2433 | static ssize_t | |
2434 | cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page) | |
2435 | { | |
2436 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
2437 | struct cfq_fs_entry *entry = to_cfq(attr); | |
2438 | ||
2439 | if (!entry->show) | |
6c1852a0 | 2440 | return -EIO; |
1da177e4 LT |
2441 | |
2442 | return entry->show(e->elevator_data, page); | |
2443 | } | |
2444 | ||
2445 | static ssize_t | |
2446 | cfq_attr_store(struct kobject *kobj, struct attribute *attr, | |
2447 | const char *page, size_t length) | |
2448 | { | |
2449 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
2450 | struct cfq_fs_entry *entry = to_cfq(attr); | |
2451 | ||
2452 | if (!entry->store) | |
6c1852a0 | 2453 | return -EIO; |
1da177e4 LT |
2454 | |
2455 | return entry->store(e->elevator_data, page, length); | |
2456 | } | |
2457 | ||
2458 | static struct sysfs_ops cfq_sysfs_ops = { | |
2459 | .show = cfq_attr_show, | |
2460 | .store = cfq_attr_store, | |
2461 | }; | |
2462 | ||
2463 | static struct kobj_type cfq_ktype = { | |
2464 | .sysfs_ops = &cfq_sysfs_ops, | |
2465 | .default_attrs = default_attrs, | |
2466 | }; | |
2467 | ||
2468 | static struct elevator_type iosched_cfq = { | |
2469 | .ops = { | |
2470 | .elevator_merge_fn = cfq_merge, | |
2471 | .elevator_merged_fn = cfq_merged_request, | |
2472 | .elevator_merge_req_fn = cfq_merged_requests, | |
b4878f24 | 2473 | .elevator_dispatch_fn = cfq_dispatch_requests, |
1da177e4 | 2474 | .elevator_add_req_fn = cfq_insert_request, |
b4878f24 | 2475 | .elevator_activate_req_fn = cfq_activate_request, |
1da177e4 LT |
2476 | .elevator_deactivate_req_fn = cfq_deactivate_request, |
2477 | .elevator_queue_empty_fn = cfq_queue_empty, | |
2478 | .elevator_completed_req_fn = cfq_completed_request, | |
2479 | .elevator_former_req_fn = cfq_former_request, | |
2480 | .elevator_latter_req_fn = cfq_latter_request, | |
2481 | .elevator_set_req_fn = cfq_set_request, | |
2482 | .elevator_put_req_fn = cfq_put_request, | |
2483 | .elevator_may_queue_fn = cfq_may_queue, | |
2484 | .elevator_init_fn = cfq_init_queue, | |
2485 | .elevator_exit_fn = cfq_exit_queue, | |
e17a9489 | 2486 | .trim = cfq_trim, |
1da177e4 LT |
2487 | }, |
2488 | .elevator_ktype = &cfq_ktype, | |
2489 | .elevator_name = "cfq", | |
2490 | .elevator_owner = THIS_MODULE, | |
2491 | }; | |
2492 | ||
2493 | static int __init cfq_init(void) | |
2494 | { | |
2495 | int ret; | |
2496 | ||
22e2c507 JA |
2497 | /* |
2498 | * could be 0 on HZ < 1000 setups | |
2499 | */ | |
2500 | if (!cfq_slice_async) | |
2501 | cfq_slice_async = 1; | |
2502 | if (!cfq_slice_idle) | |
2503 | cfq_slice_idle = 1; | |
2504 | ||
1da177e4 LT |
2505 | if (cfq_slab_setup()) |
2506 | return -ENOMEM; | |
2507 | ||
2508 | ret = elv_register(&iosched_cfq); | |
22e2c507 JA |
2509 | if (ret) |
2510 | cfq_slab_kill(); | |
1da177e4 | 2511 | |
1da177e4 LT |
2512 | return ret; |
2513 | } | |
2514 | ||
2515 | static void __exit cfq_exit(void) | |
2516 | { | |
334e94de | 2517 | DECLARE_COMPLETION(all_gone); |
1da177e4 | 2518 | elv_unregister(&iosched_cfq); |
334e94de AV |
2519 | ioc_gone = &all_gone; |
2520 | barrier(); | |
2521 | if (atomic_read(&ioc_count)) | |
2522 | complete(ioc_gone); | |
2523 | synchronize_rcu(); | |
83521d3e | 2524 | cfq_slab_kill(); |
1da177e4 LT |
2525 | } |
2526 | ||
2527 | module_init(cfq_init); | |
2528 | module_exit(cfq_exit); | |
2529 | ||
2530 | MODULE_AUTHOR("Jens Axboe"); | |
2531 | MODULE_LICENSE("GPL"); | |
2532 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |