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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/drivers/block/cfq-iosched.c | |
3 | * | |
4 | * CFQ, or complete fairness queueing, disk scheduler. | |
5 | * | |
6 | * Based on ideas from a previously unfinished io | |
7 | * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. | |
8 | * | |
9 | * Copyright (C) 2003 Jens Axboe <axboe@suse.de> | |
10 | */ | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/fs.h> | |
13 | #include <linux/blkdev.h> | |
14 | #include <linux/elevator.h> | |
15 | #include <linux/bio.h> | |
16 | #include <linux/config.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/compiler.h> | |
21 | #include <linux/hash.h> | |
22 | #include <linux/rbtree.h> | |
23 | #include <linux/mempool.h> | |
22e2c507 JA |
24 | #include <linux/ioprio.h> |
25 | #include <linux/writeback.h> | |
1da177e4 LT |
26 | |
27 | /* | |
28 | * tunables | |
29 | */ | |
30 | static int cfq_quantum = 4; /* max queue in one round of service */ | |
31 | static int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ | |
22e2c507 | 32 | static int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; |
1da177e4 LT |
33 | static int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ |
34 | static int cfq_back_penalty = 2; /* penalty of a backwards seek */ | |
35 | ||
22e2c507 | 36 | static int cfq_slice_sync = HZ / 10; |
3b18152c | 37 | static int cfq_slice_async = HZ / 25; |
22e2c507 | 38 | static int cfq_slice_async_rq = 2; |
3b18152c | 39 | static int cfq_slice_idle = HZ / 100; |
22e2c507 JA |
40 | |
41 | #define CFQ_IDLE_GRACE (HZ / 10) | |
42 | #define CFQ_SLICE_SCALE (5) | |
43 | ||
44 | #define CFQ_KEY_ASYNC (0) | |
3b18152c | 45 | #define CFQ_KEY_ANY (0xffff) |
22e2c507 JA |
46 | |
47 | /* | |
48 | * disable queueing at the driver/hardware level | |
49 | */ | |
9c2c38a1 | 50 | static int cfq_max_depth = 2; |
22e2c507 | 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) | |
87 | #define ON_RB(node) ((node)->rb_color != RB_NONE) | |
88 | #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) | |
89 | #define rq_rb_key(rq) (rq)->sector | |
90 | ||
1da177e4 LT |
91 | static kmem_cache_t *crq_pool; |
92 | static kmem_cache_t *cfq_pool; | |
93 | static kmem_cache_t *cfq_ioc_pool; | |
94 | ||
22e2c507 JA |
95 | #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
96 | #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) | |
97 | #define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) | |
98 | #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) | |
99 | ||
3b18152c JA |
100 | #define ASYNC (0) |
101 | #define SYNC (1) | |
102 | ||
103 | #define cfq_cfqq_dispatched(cfqq) \ | |
104 | ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) | |
105 | ||
106 | #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) | |
107 | ||
108 | #define cfq_cfqq_sync(cfqq) \ | |
109 | (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) | |
22e2c507 JA |
110 | |
111 | /* | |
112 | * Per block device queue structure | |
113 | */ | |
1da177e4 | 114 | struct cfq_data { |
22e2c507 JA |
115 | atomic_t ref; |
116 | request_queue_t *queue; | |
117 | ||
118 | /* | |
119 | * rr list of queues with requests and the count of them | |
120 | */ | |
121 | struct list_head rr_list[CFQ_PRIO_LISTS]; | |
122 | struct list_head busy_rr; | |
123 | struct list_head cur_rr; | |
124 | struct list_head idle_rr; | |
125 | unsigned int busy_queues; | |
126 | ||
127 | /* | |
128 | * non-ordered list of empty cfqq's | |
129 | */ | |
1da177e4 LT |
130 | struct list_head empty_list; |
131 | ||
22e2c507 JA |
132 | /* |
133 | * cfqq lookup hash | |
134 | */ | |
1da177e4 | 135 | struct hlist_head *cfq_hash; |
1da177e4 | 136 | |
22e2c507 JA |
137 | /* |
138 | * global crq hash for all queues | |
139 | */ | |
140 | struct hlist_head *crq_hash; | |
1da177e4 LT |
141 | |
142 | unsigned int max_queued; | |
143 | ||
22e2c507 | 144 | mempool_t *crq_pool; |
1da177e4 | 145 | |
22e2c507 | 146 | int rq_in_driver; |
1da177e4 | 147 | |
22e2c507 JA |
148 | /* |
149 | * schedule slice state info | |
150 | */ | |
151 | /* | |
152 | * idle window management | |
153 | */ | |
154 | struct timer_list idle_slice_timer; | |
155 | struct work_struct unplug_work; | |
1da177e4 | 156 | |
22e2c507 JA |
157 | struct cfq_queue *active_queue; |
158 | struct cfq_io_context *active_cic; | |
159 | int cur_prio, cur_end_prio; | |
160 | unsigned int dispatch_slice; | |
161 | ||
162 | struct timer_list idle_class_timer; | |
1da177e4 LT |
163 | |
164 | sector_t last_sector; | |
22e2c507 | 165 | unsigned long last_end_request; |
1da177e4 | 166 | |
22e2c507 | 167 | unsigned int rq_starved; |
1da177e4 LT |
168 | |
169 | /* | |
170 | * tunables, see top of file | |
171 | */ | |
172 | unsigned int cfq_quantum; | |
173 | unsigned int cfq_queued; | |
22e2c507 | 174 | unsigned int cfq_fifo_expire[2]; |
1da177e4 LT |
175 | unsigned int cfq_back_penalty; |
176 | unsigned int cfq_back_max; | |
22e2c507 JA |
177 | unsigned int cfq_slice[2]; |
178 | unsigned int cfq_slice_async_rq; | |
179 | unsigned int cfq_slice_idle; | |
180 | unsigned int cfq_max_depth; | |
1da177e4 LT |
181 | }; |
182 | ||
22e2c507 JA |
183 | /* |
184 | * Per process-grouping structure | |
185 | */ | |
1da177e4 LT |
186 | struct cfq_queue { |
187 | /* reference count */ | |
188 | atomic_t ref; | |
189 | /* parent cfq_data */ | |
190 | struct cfq_data *cfqd; | |
22e2c507 | 191 | /* cfqq lookup hash */ |
1da177e4 LT |
192 | struct hlist_node cfq_hash; |
193 | /* hash key */ | |
22e2c507 | 194 | unsigned int key; |
1da177e4 LT |
195 | /* on either rr or empty list of cfqd */ |
196 | struct list_head cfq_list; | |
197 | /* sorted list of pending requests */ | |
198 | struct rb_root sort_list; | |
199 | /* if fifo isn't expired, next request to serve */ | |
200 | struct cfq_rq *next_crq; | |
201 | /* requests queued in sort_list */ | |
202 | int queued[2]; | |
203 | /* currently allocated requests */ | |
204 | int allocated[2]; | |
205 | /* fifo list of requests in sort_list */ | |
22e2c507 | 206 | struct list_head fifo; |
1da177e4 | 207 | |
22e2c507 JA |
208 | unsigned long slice_start; |
209 | unsigned long slice_end; | |
210 | unsigned long slice_left; | |
211 | unsigned long service_last; | |
1da177e4 | 212 | |
3b18152c JA |
213 | /* number of requests that are on the dispatch list */ |
214 | int on_dispatch[2]; | |
22e2c507 JA |
215 | |
216 | /* io prio of this group */ | |
217 | unsigned short ioprio, org_ioprio; | |
218 | unsigned short ioprio_class, org_ioprio_class; | |
219 | ||
3b18152c JA |
220 | /* various state flags, see below */ |
221 | unsigned int flags; | |
1da177e4 LT |
222 | }; |
223 | ||
224 | struct cfq_rq { | |
225 | struct rb_node rb_node; | |
226 | sector_t rb_key; | |
227 | struct request *request; | |
228 | struct hlist_node hash; | |
229 | ||
230 | struct cfq_queue *cfq_queue; | |
231 | struct cfq_io_context *io_context; | |
232 | ||
3b18152c | 233 | unsigned int crq_flags; |
1da177e4 LT |
234 | }; |
235 | ||
3b18152c JA |
236 | enum cfqq_state_flags { |
237 | CFQ_CFQQ_FLAG_on_rr = 0, | |
238 | CFQ_CFQQ_FLAG_wait_request, | |
239 | CFQ_CFQQ_FLAG_must_alloc, | |
240 | CFQ_CFQQ_FLAG_must_alloc_slice, | |
241 | CFQ_CFQQ_FLAG_must_dispatch, | |
242 | CFQ_CFQQ_FLAG_fifo_expire, | |
243 | CFQ_CFQQ_FLAG_idle_window, | |
244 | CFQ_CFQQ_FLAG_prio_changed, | |
245 | CFQ_CFQQ_FLAG_expired, | |
246 | }; | |
247 | ||
248 | #define CFQ_CFQQ_FNS(name) \ | |
249 | static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ | |
250 | { \ | |
251 | cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ | |
252 | } \ | |
253 | static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ | |
254 | { \ | |
255 | cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ | |
256 | } \ | |
257 | static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ | |
258 | { \ | |
259 | return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ | |
260 | } | |
261 | ||
262 | CFQ_CFQQ_FNS(on_rr); | |
263 | CFQ_CFQQ_FNS(wait_request); | |
264 | CFQ_CFQQ_FNS(must_alloc); | |
265 | CFQ_CFQQ_FNS(must_alloc_slice); | |
266 | CFQ_CFQQ_FNS(must_dispatch); | |
267 | CFQ_CFQQ_FNS(fifo_expire); | |
268 | CFQ_CFQQ_FNS(idle_window); | |
269 | CFQ_CFQQ_FNS(prio_changed); | |
270 | CFQ_CFQQ_FNS(expired); | |
271 | #undef CFQ_CFQQ_FNS | |
272 | ||
273 | enum cfq_rq_state_flags { | |
274 | CFQ_CRQ_FLAG_in_flight = 0, | |
275 | CFQ_CRQ_FLAG_in_driver, | |
276 | CFQ_CRQ_FLAG_is_sync, | |
277 | CFQ_CRQ_FLAG_requeued, | |
278 | }; | |
279 | ||
280 | #define CFQ_CRQ_FNS(name) \ | |
281 | static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \ | |
282 | { \ | |
283 | crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \ | |
284 | } \ | |
285 | static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \ | |
286 | { \ | |
287 | crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \ | |
288 | } \ | |
289 | static inline int cfq_crq_##name(const struct cfq_rq *crq) \ | |
290 | { \ | |
291 | return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \ | |
292 | } | |
293 | ||
294 | CFQ_CRQ_FNS(in_flight); | |
295 | CFQ_CRQ_FNS(in_driver); | |
296 | CFQ_CRQ_FNS(is_sync); | |
297 | CFQ_CRQ_FNS(requeued); | |
298 | #undef CFQ_CRQ_FNS | |
299 | ||
300 | static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); | |
1da177e4 | 301 | static void cfq_dispatch_sort(request_queue_t *, struct cfq_rq *); |
1da177e4 LT |
302 | static void cfq_put_cfqd(struct cfq_data *cfqd); |
303 | ||
22e2c507 | 304 | #define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) |
1da177e4 LT |
305 | |
306 | /* | |
307 | * lots of deadline iosched dupes, can be abstracted later... | |
308 | */ | |
309 | static inline void cfq_del_crq_hash(struct cfq_rq *crq) | |
310 | { | |
311 | hlist_del_init(&crq->hash); | |
312 | } | |
313 | ||
314 | static void cfq_remove_merge_hints(request_queue_t *q, struct cfq_rq *crq) | |
315 | { | |
316 | cfq_del_crq_hash(crq); | |
317 | ||
318 | if (q->last_merge == crq->request) | |
319 | q->last_merge = NULL; | |
1da177e4 LT |
320 | } |
321 | ||
322 | static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) | |
323 | { | |
324 | const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); | |
325 | ||
1da177e4 LT |
326 | hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); |
327 | } | |
328 | ||
329 | static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) | |
330 | { | |
331 | struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)]; | |
332 | struct hlist_node *entry, *next; | |
333 | ||
334 | hlist_for_each_safe(entry, next, hash_list) { | |
335 | struct cfq_rq *crq = list_entry_hash(entry); | |
336 | struct request *__rq = crq->request; | |
337 | ||
1da177e4 LT |
338 | if (!rq_mergeable(__rq)) { |
339 | cfq_del_crq_hash(crq); | |
340 | continue; | |
341 | } | |
342 | ||
343 | if (rq_hash_key(__rq) == offset) | |
344 | return __rq; | |
345 | } | |
346 | ||
347 | return NULL; | |
348 | } | |
349 | ||
99f95e52 AM |
350 | static inline int cfq_pending_requests(struct cfq_data *cfqd) |
351 | { | |
352 | return !list_empty(&cfqd->queue->queue_head) || cfqd->busy_queues; | |
353 | } | |
354 | ||
355 | /* | |
356 | * scheduler run of queue, if there are requests pending and no one in the | |
357 | * driver that will restart queueing | |
358 | */ | |
359 | static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) | |
360 | { | |
361 | if (!cfqd->rq_in_driver && cfq_pending_requests(cfqd)) | |
362 | kblockd_schedule_work(&cfqd->unplug_work); | |
363 | } | |
364 | ||
365 | static int cfq_queue_empty(request_queue_t *q) | |
366 | { | |
367 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
368 | ||
369 | return !cfq_pending_requests(cfqd); | |
370 | } | |
371 | ||
1da177e4 LT |
372 | /* |
373 | * Lifted from AS - choose which of crq1 and crq2 that is best served now. | |
374 | * We choose the request that is closest to the head right now. Distance | |
375 | * behind the head are penalized and only allowed to a certain extent. | |
376 | */ | |
377 | static struct cfq_rq * | |
378 | cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) | |
379 | { | |
380 | sector_t last, s1, s2, d1 = 0, d2 = 0; | |
381 | int r1_wrap = 0, r2_wrap = 0; /* requests are behind the disk head */ | |
382 | unsigned long back_max; | |
383 | ||
384 | if (crq1 == NULL || crq1 == crq2) | |
385 | return crq2; | |
386 | if (crq2 == NULL) | |
387 | return crq1; | |
9c2c38a1 JA |
388 | |
389 | if (cfq_crq_requeued(crq1) && !cfq_crq_requeued(crq2)) | |
22e2c507 | 390 | return crq1; |
9c2c38a1 JA |
391 | else if (cfq_crq_requeued(crq2) && !cfq_crq_requeued(crq1)) |
392 | return crq2; | |
393 | ||
394 | if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2)) | |
395 | return crq1; | |
396 | else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1)) | |
22e2c507 | 397 | return crq2; |
1da177e4 LT |
398 | |
399 | s1 = crq1->request->sector; | |
400 | s2 = crq2->request->sector; | |
401 | ||
402 | last = cfqd->last_sector; | |
403 | ||
1da177e4 LT |
404 | /* |
405 | * by definition, 1KiB is 2 sectors | |
406 | */ | |
407 | back_max = cfqd->cfq_back_max * 2; | |
408 | ||
409 | /* | |
410 | * Strict one way elevator _except_ in the case where we allow | |
411 | * short backward seeks which are biased as twice the cost of a | |
412 | * similar forward seek. | |
413 | */ | |
414 | if (s1 >= last) | |
415 | d1 = s1 - last; | |
416 | else if (s1 + back_max >= last) | |
417 | d1 = (last - s1) * cfqd->cfq_back_penalty; | |
418 | else | |
419 | r1_wrap = 1; | |
420 | ||
421 | if (s2 >= last) | |
422 | d2 = s2 - last; | |
423 | else if (s2 + back_max >= last) | |
424 | d2 = (last - s2) * cfqd->cfq_back_penalty; | |
425 | else | |
426 | r2_wrap = 1; | |
427 | ||
428 | /* Found required data */ | |
429 | if (!r1_wrap && r2_wrap) | |
430 | return crq1; | |
431 | else if (!r2_wrap && r1_wrap) | |
432 | return crq2; | |
433 | else if (r1_wrap && r2_wrap) { | |
434 | /* both behind the head */ | |
435 | if (s1 <= s2) | |
436 | return crq1; | |
437 | else | |
438 | return crq2; | |
439 | } | |
440 | ||
441 | /* Both requests in front of the head */ | |
442 | if (d1 < d2) | |
443 | return crq1; | |
444 | else if (d2 < d1) | |
445 | return crq2; | |
446 | else { | |
447 | if (s1 >= s2) | |
448 | return crq1; | |
449 | else | |
450 | return crq2; | |
451 | } | |
452 | } | |
453 | ||
454 | /* | |
455 | * would be nice to take fifo expire time into account as well | |
456 | */ | |
457 | static struct cfq_rq * | |
458 | cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
459 | struct cfq_rq *last) | |
460 | { | |
461 | struct cfq_rq *crq_next = NULL, *crq_prev = NULL; | |
462 | struct rb_node *rbnext, *rbprev; | |
463 | ||
3d25f356 | 464 | rbnext = NULL; |
22e2c507 JA |
465 | if (ON_RB(&last->rb_node)) |
466 | rbnext = rb_next(&last->rb_node); | |
3d25f356 | 467 | if (!rbnext) { |
1da177e4 | 468 | rbnext = rb_first(&cfqq->sort_list); |
22e2c507 JA |
469 | if (rbnext == &last->rb_node) |
470 | rbnext = NULL; | |
471 | } | |
1da177e4 LT |
472 | |
473 | rbprev = rb_prev(&last->rb_node); | |
474 | ||
475 | if (rbprev) | |
476 | crq_prev = rb_entry_crq(rbprev); | |
477 | if (rbnext) | |
478 | crq_next = rb_entry_crq(rbnext); | |
479 | ||
480 | return cfq_choose_req(cfqd, crq_next, crq_prev); | |
481 | } | |
482 | ||
483 | static void cfq_update_next_crq(struct cfq_rq *crq) | |
484 | { | |
485 | struct cfq_queue *cfqq = crq->cfq_queue; | |
486 | ||
487 | if (cfqq->next_crq == crq) | |
488 | cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); | |
489 | } | |
490 | ||
22e2c507 | 491 | static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
1da177e4 | 492 | { |
22e2c507 JA |
493 | struct cfq_data *cfqd = cfqq->cfqd; |
494 | struct list_head *list, *entry; | |
1da177e4 | 495 | |
3b18152c | 496 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 497 | |
22e2c507 | 498 | list_del(&cfqq->cfq_list); |
1da177e4 | 499 | |
22e2c507 JA |
500 | if (cfq_class_rt(cfqq)) |
501 | list = &cfqd->cur_rr; | |
502 | else if (cfq_class_idle(cfqq)) | |
503 | list = &cfqd->idle_rr; | |
504 | else { | |
505 | /* | |
506 | * if cfqq has requests in flight, don't allow it to be | |
507 | * found in cfq_set_active_queue before it has finished them. | |
508 | * this is done to increase fairness between a process that | |
509 | * has lots of io pending vs one that only generates one | |
510 | * sporadically or synchronously | |
511 | */ | |
3b18152c | 512 | if (cfq_cfqq_dispatched(cfqq)) |
22e2c507 JA |
513 | list = &cfqd->busy_rr; |
514 | else | |
515 | list = &cfqd->rr_list[cfqq->ioprio]; | |
1da177e4 LT |
516 | } |
517 | ||
22e2c507 JA |
518 | /* |
519 | * if queue was preempted, just add to front to be fair. busy_rr | |
520 | * isn't sorted. | |
521 | */ | |
522 | if (preempted || list == &cfqd->busy_rr) { | |
523 | list_add(&cfqq->cfq_list, list); | |
1da177e4 | 524 | return; |
22e2c507 | 525 | } |
1da177e4 LT |
526 | |
527 | /* | |
22e2c507 | 528 | * sort by when queue was last serviced |
1da177e4 | 529 | */ |
22e2c507 JA |
530 | entry = list; |
531 | while ((entry = entry->prev) != list) { | |
1da177e4 LT |
532 | struct cfq_queue *__cfqq = list_entry_cfqq(entry); |
533 | ||
22e2c507 JA |
534 | if (!__cfqq->service_last) |
535 | break; | |
536 | if (time_before(__cfqq->service_last, cfqq->service_last)) | |
1da177e4 | 537 | break; |
1da177e4 LT |
538 | } |
539 | ||
540 | list_add(&cfqq->cfq_list, entry); | |
541 | } | |
542 | ||
543 | /* | |
544 | * add to busy list of queues for service, trying to be fair in ordering | |
22e2c507 | 545 | * the pending list according to last request service |
1da177e4 LT |
546 | */ |
547 | static inline void | |
22e2c507 | 548 | cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq, int requeue) |
1da177e4 | 549 | { |
3b18152c JA |
550 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
551 | cfq_mark_cfqq_on_rr(cfqq); | |
1da177e4 LT |
552 | cfqd->busy_queues++; |
553 | ||
22e2c507 | 554 | cfq_resort_rr_list(cfqq, requeue); |
1da177e4 LT |
555 | } |
556 | ||
557 | static inline void | |
558 | cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
559 | { | |
3b18152c JA |
560 | BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
561 | cfq_clear_cfqq_on_rr(cfqq); | |
22e2c507 | 562 | list_move(&cfqq->cfq_list, &cfqd->empty_list); |
1da177e4 LT |
563 | |
564 | BUG_ON(!cfqd->busy_queues); | |
565 | cfqd->busy_queues--; | |
566 | } | |
567 | ||
568 | /* | |
569 | * rb tree support functions | |
570 | */ | |
571 | static inline void cfq_del_crq_rb(struct cfq_rq *crq) | |
572 | { | |
573 | struct cfq_queue *cfqq = crq->cfq_queue; | |
574 | ||
575 | if (ON_RB(&crq->rb_node)) { | |
576 | struct cfq_data *cfqd = cfqq->cfqd; | |
3b18152c | 577 | const int sync = cfq_crq_is_sync(crq); |
1da177e4 | 578 | |
22e2c507 JA |
579 | BUG_ON(!cfqq->queued[sync]); |
580 | cfqq->queued[sync]--; | |
1da177e4 LT |
581 | |
582 | cfq_update_next_crq(crq); | |
583 | ||
1da177e4 LT |
584 | rb_erase(&crq->rb_node, &cfqq->sort_list); |
585 | RB_CLEAR_COLOR(&crq->rb_node); | |
586 | ||
3b18152c | 587 | if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list)) |
1da177e4 LT |
588 | cfq_del_cfqq_rr(cfqd, cfqq); |
589 | } | |
590 | } | |
591 | ||
592 | static struct cfq_rq * | |
593 | __cfq_add_crq_rb(struct cfq_rq *crq) | |
594 | { | |
595 | struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; | |
596 | struct rb_node *parent = NULL; | |
597 | struct cfq_rq *__crq; | |
598 | ||
599 | while (*p) { | |
600 | parent = *p; | |
601 | __crq = rb_entry_crq(parent); | |
602 | ||
603 | if (crq->rb_key < __crq->rb_key) | |
604 | p = &(*p)->rb_left; | |
605 | else if (crq->rb_key > __crq->rb_key) | |
606 | p = &(*p)->rb_right; | |
607 | else | |
608 | return __crq; | |
609 | } | |
610 | ||
611 | rb_link_node(&crq->rb_node, parent, p); | |
612 | return NULL; | |
613 | } | |
614 | ||
615 | static void cfq_add_crq_rb(struct cfq_rq *crq) | |
616 | { | |
617 | struct cfq_queue *cfqq = crq->cfq_queue; | |
618 | struct cfq_data *cfqd = cfqq->cfqd; | |
619 | struct request *rq = crq->request; | |
620 | struct cfq_rq *__alias; | |
621 | ||
622 | crq->rb_key = rq_rb_key(rq); | |
3b18152c | 623 | cfqq->queued[cfq_crq_is_sync(crq)]++; |
1da177e4 LT |
624 | |
625 | /* | |
626 | * looks a little odd, but the first insert might return an alias. | |
627 | * if that happens, put the alias on the dispatch list | |
628 | */ | |
629 | while ((__alias = __cfq_add_crq_rb(crq)) != NULL) | |
630 | cfq_dispatch_sort(cfqd->queue, __alias); | |
631 | ||
632 | rb_insert_color(&crq->rb_node, &cfqq->sort_list); | |
633 | ||
3b18152c JA |
634 | if (!cfq_cfqq_on_rr(cfqq)) |
635 | cfq_add_cfqq_rr(cfqd, cfqq, cfq_crq_requeued(crq)); | |
1da177e4 LT |
636 | |
637 | /* | |
638 | * check if this request is a better next-serve candidate | |
639 | */ | |
640 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
641 | } | |
642 | ||
643 | static inline void | |
644 | cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) | |
645 | { | |
646 | if (ON_RB(&crq->rb_node)) { | |
647 | rb_erase(&crq->rb_node, &cfqq->sort_list); | |
3b18152c | 648 | cfqq->queued[cfq_crq_is_sync(crq)]--; |
1da177e4 LT |
649 | } |
650 | ||
651 | cfq_add_crq_rb(crq); | |
652 | } | |
653 | ||
22e2c507 JA |
654 | static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) |
655 | ||
1da177e4 | 656 | { |
3b18152c | 657 | struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY); |
1da177e4 LT |
658 | struct rb_node *n; |
659 | ||
660 | if (!cfqq) | |
661 | goto out; | |
662 | ||
663 | n = cfqq->sort_list.rb_node; | |
664 | while (n) { | |
665 | struct cfq_rq *crq = rb_entry_crq(n); | |
666 | ||
667 | if (sector < crq->rb_key) | |
668 | n = n->rb_left; | |
669 | else if (sector > crq->rb_key) | |
670 | n = n->rb_right; | |
671 | else | |
672 | return crq->request; | |
673 | } | |
674 | ||
675 | out: | |
676 | return NULL; | |
677 | } | |
678 | ||
679 | static void cfq_deactivate_request(request_queue_t *q, struct request *rq) | |
680 | { | |
22e2c507 | 681 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1da177e4 LT |
682 | struct cfq_rq *crq = RQ_DATA(rq); |
683 | ||
684 | if (crq) { | |
685 | struct cfq_queue *cfqq = crq->cfq_queue; | |
686 | ||
3b18152c JA |
687 | if (cfq_crq_in_driver(crq)) { |
688 | cfq_clear_crq_in_driver(crq); | |
22e2c507 JA |
689 | WARN_ON(!cfqd->rq_in_driver); |
690 | cfqd->rq_in_driver--; | |
1da177e4 | 691 | } |
3b18152c JA |
692 | if (cfq_crq_in_flight(crq)) { |
693 | const int sync = cfq_crq_is_sync(crq); | |
694 | ||
695 | cfq_clear_crq_in_flight(crq); | |
696 | WARN_ON(!cfqq->on_dispatch[sync]); | |
697 | cfqq->on_dispatch[sync]--; | |
22e2c507 | 698 | } |
3b18152c | 699 | cfq_mark_crq_requeued(crq); |
1da177e4 LT |
700 | } |
701 | } | |
702 | ||
703 | /* | |
704 | * make sure the service time gets corrected on reissue of this request | |
705 | */ | |
706 | static void cfq_requeue_request(request_queue_t *q, struct request *rq) | |
707 | { | |
708 | cfq_deactivate_request(q, rq); | |
709 | list_add(&rq->queuelist, &q->queue_head); | |
710 | } | |
711 | ||
712 | static void cfq_remove_request(request_queue_t *q, struct request *rq) | |
713 | { | |
714 | struct cfq_rq *crq = RQ_DATA(rq); | |
715 | ||
716 | if (crq) { | |
1da177e4 | 717 | list_del_init(&rq->queuelist); |
22e2c507 JA |
718 | cfq_del_crq_rb(crq); |
719 | cfq_remove_merge_hints(q, crq); | |
1da177e4 | 720 | |
1da177e4 LT |
721 | } |
722 | } | |
723 | ||
724 | static int | |
725 | cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
726 | { | |
727 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
728 | struct request *__rq; | |
729 | int ret; | |
730 | ||
731 | ret = elv_try_last_merge(q, bio); | |
732 | if (ret != ELEVATOR_NO_MERGE) { | |
733 | __rq = q->last_merge; | |
734 | goto out_insert; | |
735 | } | |
736 | ||
737 | __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); | |
22e2c507 JA |
738 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
739 | ret = ELEVATOR_BACK_MERGE; | |
740 | goto out; | |
1da177e4 LT |
741 | } |
742 | ||
743 | __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); | |
22e2c507 JA |
744 | if (__rq && elv_rq_merge_ok(__rq, bio)) { |
745 | ret = ELEVATOR_FRONT_MERGE; | |
746 | goto out; | |
1da177e4 LT |
747 | } |
748 | ||
749 | return ELEVATOR_NO_MERGE; | |
750 | out: | |
751 | q->last_merge = __rq; | |
752 | out_insert: | |
753 | *req = __rq; | |
754 | return ret; | |
755 | } | |
756 | ||
757 | static void cfq_merged_request(request_queue_t *q, struct request *req) | |
758 | { | |
759 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
760 | struct cfq_rq *crq = RQ_DATA(req); | |
761 | ||
762 | cfq_del_crq_hash(crq); | |
763 | cfq_add_crq_hash(cfqd, crq); | |
764 | ||
765 | if (ON_RB(&crq->rb_node) && (rq_rb_key(req) != crq->rb_key)) { | |
766 | struct cfq_queue *cfqq = crq->cfq_queue; | |
767 | ||
768 | cfq_update_next_crq(crq); | |
769 | cfq_reposition_crq_rb(cfqq, crq); | |
770 | } | |
771 | ||
772 | q->last_merge = req; | |
773 | } | |
774 | ||
775 | static void | |
776 | cfq_merged_requests(request_queue_t *q, struct request *rq, | |
777 | struct request *next) | |
778 | { | |
1da177e4 LT |
779 | cfq_merged_request(q, rq); |
780 | ||
22e2c507 JA |
781 | /* |
782 | * reposition in fifo if next is older than rq | |
783 | */ | |
784 | if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && | |
785 | time_before(next->start_time, rq->start_time)) | |
786 | list_move(&rq->queuelist, &next->queuelist); | |
787 | ||
788 | cfq_remove_request(q, next); | |
789 | } | |
790 | ||
791 | static inline void | |
792 | __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
793 | { | |
794 | if (cfqq) { | |
795 | /* | |
796 | * stop potential idle class queues waiting service | |
797 | */ | |
798 | del_timer(&cfqd->idle_class_timer); | |
799 | ||
800 | cfqq->slice_start = jiffies; | |
801 | cfqq->slice_end = 0; | |
802 | cfqq->slice_left = 0; | |
3b18152c JA |
803 | cfq_clear_cfqq_must_alloc_slice(cfqq); |
804 | cfq_clear_cfqq_fifo_expire(cfqq); | |
805 | cfq_clear_cfqq_expired(cfqq); | |
22e2c507 JA |
806 | } |
807 | ||
808 | cfqd->active_queue = cfqq; | |
809 | } | |
810 | ||
811 | /* | |
812 | * 0 | |
813 | * 0,1 | |
814 | * 0,1,2 | |
815 | * 0,1,2,3 | |
816 | * 0,1,2,3,4 | |
817 | * 0,1,2,3,4,5 | |
818 | * 0,1,2,3,4,5,6 | |
819 | * 0,1,2,3,4,5,6,7 | |
820 | */ | |
821 | static int cfq_get_next_prio_level(struct cfq_data *cfqd) | |
822 | { | |
823 | int prio, wrap; | |
824 | ||
825 | prio = -1; | |
826 | wrap = 0; | |
827 | do { | |
828 | int p; | |
829 | ||
830 | for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { | |
831 | if (!list_empty(&cfqd->rr_list[p])) { | |
832 | prio = p; | |
833 | break; | |
834 | } | |
835 | } | |
836 | ||
837 | if (prio != -1) | |
838 | break; | |
839 | cfqd->cur_prio = 0; | |
840 | if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
841 | cfqd->cur_end_prio = 0; | |
842 | if (wrap) | |
843 | break; | |
844 | wrap = 1; | |
1da177e4 | 845 | } |
22e2c507 JA |
846 | } while (1); |
847 | ||
848 | if (unlikely(prio == -1)) | |
849 | return -1; | |
850 | ||
851 | BUG_ON(prio >= CFQ_PRIO_LISTS); | |
852 | ||
853 | list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); | |
854 | ||
855 | cfqd->cur_prio = prio + 1; | |
856 | if (cfqd->cur_prio > cfqd->cur_end_prio) { | |
857 | cfqd->cur_end_prio = cfqd->cur_prio; | |
858 | cfqd->cur_prio = 0; | |
859 | } | |
860 | if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { | |
861 | cfqd->cur_prio = 0; | |
862 | cfqd->cur_end_prio = 0; | |
1da177e4 LT |
863 | } |
864 | ||
22e2c507 JA |
865 | return prio; |
866 | } | |
867 | ||
3b18152c | 868 | static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
22e2c507 | 869 | { |
3b18152c JA |
870 | struct cfq_queue *cfqq; |
871 | ||
872 | /* | |
873 | * if current queue is expired but not done with its requests yet, | |
874 | * wait for that to happen | |
875 | */ | |
876 | if ((cfqq = cfqd->active_queue) != NULL) { | |
877 | if (cfq_cfqq_expired(cfqq) && cfq_cfqq_dispatched(cfqq)) | |
878 | return NULL; | |
879 | } | |
22e2c507 JA |
880 | |
881 | /* | |
882 | * if current list is non-empty, grab first entry. if it is empty, | |
883 | * get next prio level and grab first entry then if any are spliced | |
884 | */ | |
885 | if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) | |
886 | cfqq = list_entry_cfqq(cfqd->cur_rr.next); | |
887 | ||
888 | /* | |
889 | * if we have idle queues and no rt or be queues had pending | |
890 | * requests, either allow immediate service if the grace period | |
891 | * has passed or arm the idle grace timer | |
892 | */ | |
893 | if (!cfqq && !list_empty(&cfqd->idle_rr)) { | |
894 | unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
895 | ||
896 | if (time_after_eq(jiffies, end)) | |
897 | cfqq = list_entry_cfqq(cfqd->idle_rr.next); | |
898 | else | |
899 | mod_timer(&cfqd->idle_class_timer, end); | |
900 | } | |
901 | ||
902 | __cfq_set_active_queue(cfqd, cfqq); | |
3b18152c | 903 | return cfqq; |
22e2c507 JA |
904 | } |
905 | ||
906 | /* | |
907 | * current cfqq expired its slice (or was too idle), select new one | |
908 | */ | |
3b18152c JA |
909 | static void |
910 | __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
911 | int preempted) | |
22e2c507 | 912 | { |
3b18152c | 913 | unsigned long now = jiffies; |
22e2c507 | 914 | |
3b18152c JA |
915 | if (cfq_cfqq_wait_request(cfqq)) |
916 | del_timer(&cfqd->idle_slice_timer); | |
22e2c507 | 917 | |
3b18152c JA |
918 | if (!preempted && !cfq_cfqq_dispatched(cfqq)) |
919 | cfqq->service_last = now; | |
22e2c507 | 920 | |
3b18152c JA |
921 | cfq_clear_cfqq_must_dispatch(cfqq); |
922 | cfq_clear_cfqq_wait_request(cfqq); | |
22e2c507 | 923 | |
3b18152c JA |
924 | /* |
925 | * store what was left of this slice, if the queue idled out | |
926 | * or was preempted | |
927 | */ | |
928 | if (time_after(now, cfqq->slice_end)) | |
929 | cfqq->slice_left = now - cfqq->slice_end; | |
930 | else | |
931 | cfqq->slice_left = 0; | |
22e2c507 | 932 | |
3b18152c JA |
933 | if (cfq_cfqq_on_rr(cfqq)) |
934 | cfq_resort_rr_list(cfqq, preempted); | |
22e2c507 | 935 | |
3b18152c | 936 | if (cfqq == cfqd->active_queue) |
22e2c507 JA |
937 | cfqd->active_queue = NULL; |
938 | ||
3b18152c JA |
939 | if (cfqd->active_cic) { |
940 | put_io_context(cfqd->active_cic->ioc); | |
941 | cfqd->active_cic = NULL; | |
22e2c507 JA |
942 | } |
943 | ||
944 | cfqd->dispatch_slice = 0; | |
945 | } | |
946 | ||
3b18152c JA |
947 | static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) |
948 | { | |
949 | struct cfq_queue *cfqq = cfqd->active_queue; | |
950 | ||
951 | if (cfqq) { | |
952 | /* | |
953 | * use deferred expiry, if there are requests in progress as | |
954 | * not to disturb the slice of the next queue | |
955 | */ | |
956 | if (cfq_cfqq_dispatched(cfqq)) | |
957 | cfq_mark_cfqq_expired(cfqq); | |
958 | else | |
959 | __cfq_slice_expired(cfqd, cfqq, preempted); | |
960 | } | |
961 | } | |
962 | ||
22e2c507 JA |
963 | static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
964 | ||
965 | { | |
966 | WARN_ON(!RB_EMPTY(&cfqq->sort_list)); | |
967 | WARN_ON(cfqq != cfqd->active_queue); | |
968 | ||
969 | /* | |
970 | * idle is disabled, either manually or by past process history | |
971 | */ | |
972 | if (!cfqd->cfq_slice_idle) | |
973 | return 0; | |
3b18152c | 974 | if (!cfq_cfqq_idle_window(cfqq)) |
22e2c507 JA |
975 | return 0; |
976 | /* | |
977 | * task has exited, don't wait | |
978 | */ | |
979 | if (cfqd->active_cic && !cfqd->active_cic->ioc->task) | |
980 | return 0; | |
981 | ||
3b18152c JA |
982 | cfq_mark_cfqq_must_dispatch(cfqq); |
983 | cfq_mark_cfqq_wait_request(cfqq); | |
22e2c507 JA |
984 | |
985 | if (!timer_pending(&cfqd->idle_slice_timer)) { | |
3b18152c | 986 | unsigned long slice_left = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
22e2c507 | 987 | |
3b18152c | 988 | cfqd->idle_slice_timer.expires = jiffies + slice_left; |
22e2c507 JA |
989 | add_timer(&cfqd->idle_slice_timer); |
990 | } | |
991 | ||
992 | return 1; | |
1da177e4 LT |
993 | } |
994 | ||
995 | /* | |
996 | * we dispatch cfqd->cfq_quantum requests in total from the rr_list queues, | |
997 | * this function sector sorts the selected request to minimize seeks. we start | |
998 | * at cfqd->last_sector, not 0. | |
999 | */ | |
1000 | static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq) | |
1001 | { | |
1002 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1003 | struct cfq_queue *cfqq = crq->cfq_queue; | |
1004 | struct list_head *head = &q->queue_head, *entry = head; | |
1005 | struct request *__rq; | |
1006 | sector_t last; | |
1007 | ||
1da177e4 LT |
1008 | list_del(&crq->request->queuelist); |
1009 | ||
1010 | last = cfqd->last_sector; | |
22e2c507 JA |
1011 | list_for_each_entry_reverse(__rq, head, queuelist) { |
1012 | struct cfq_rq *__crq = RQ_DATA(__rq); | |
1da177e4 | 1013 | |
22e2c507 JA |
1014 | if (blk_barrier_rq(__rq)) |
1015 | break; | |
1016 | if (!blk_fs_request(__rq)) | |
1da177e4 | 1017 | break; |
3b18152c | 1018 | if (cfq_crq_requeued(__crq)) |
1da177e4 LT |
1019 | break; |
1020 | ||
22e2c507 | 1021 | if (__rq->sector <= crq->request->sector) |
1da177e4 LT |
1022 | break; |
1023 | if (__rq->sector > last && crq->request->sector < last) { | |
22e2c507 | 1024 | last = crq->request->sector + crq->request->nr_sectors; |
1da177e4 LT |
1025 | break; |
1026 | } | |
22e2c507 | 1027 | entry = &__rq->queuelist; |
1da177e4 LT |
1028 | } |
1029 | ||
1030 | cfqd->last_sector = last; | |
22e2c507 JA |
1031 | |
1032 | cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); | |
1033 | ||
1034 | cfq_del_crq_rb(crq); | |
1035 | cfq_remove_merge_hints(q, crq); | |
1036 | ||
3b18152c JA |
1037 | cfq_mark_crq_in_flight(crq); |
1038 | cfq_clear_crq_requeued(crq); | |
1039 | ||
1040 | cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; | |
22e2c507 | 1041 | list_add_tail(&crq->request->queuelist, entry); |
1da177e4 LT |
1042 | } |
1043 | ||
1044 | /* | |
1045 | * return expired entry, or NULL to just start from scratch in rbtree | |
1046 | */ | |
1047 | static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) | |
1048 | { | |
1049 | struct cfq_data *cfqd = cfqq->cfqd; | |
22e2c507 | 1050 | struct request *rq; |
1da177e4 LT |
1051 | struct cfq_rq *crq; |
1052 | ||
3b18152c | 1053 | if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4 LT |
1054 | return NULL; |
1055 | ||
22e2c507 | 1056 | if (!list_empty(&cfqq->fifo)) { |
3b18152c | 1057 | int fifo = cfq_cfqq_class_sync(cfqq); |
1da177e4 | 1058 | |
22e2c507 JA |
1059 | crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); |
1060 | rq = crq->request; | |
1061 | if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { | |
3b18152c | 1062 | cfq_mark_cfqq_fifo_expire(cfqq); |
22e2c507 JA |
1063 | return crq; |
1064 | } | |
1da177e4 LT |
1065 | } |
1066 | ||
1067 | return NULL; | |
1068 | } | |
1069 | ||
1070 | /* | |
3b18152c JA |
1071 | * Scale schedule slice based on io priority. Use the sync time slice only |
1072 | * if a queue is marked sync and has sync io queued. A sync queue with async | |
1073 | * io only, should not get full sync slice length. | |
1da177e4 | 1074 | */ |
22e2c507 JA |
1075 | static inline int |
1076 | cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1077 | { | |
1078 | const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; | |
1079 | ||
1080 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); | |
1081 | ||
1082 | return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); | |
1083 | } | |
1084 | ||
1da177e4 | 1085 | static inline void |
22e2c507 | 1086 | cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4 | 1087 | { |
22e2c507 JA |
1088 | cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; |
1089 | } | |
1da177e4 | 1090 | |
22e2c507 JA |
1091 | static inline int |
1092 | cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1093 | { | |
1094 | const int base_rq = cfqd->cfq_slice_async_rq; | |
1da177e4 | 1095 | |
22e2c507 | 1096 | WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4 | 1097 | |
22e2c507 | 1098 | return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4 LT |
1099 | } |
1100 | ||
22e2c507 JA |
1101 | /* |
1102 | * get next queue for service | |
1103 | */ | |
1104 | static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force) | |
1da177e4 | 1105 | { |
22e2c507 | 1106 | unsigned long now = jiffies; |
1da177e4 | 1107 | struct cfq_queue *cfqq; |
1da177e4 | 1108 | |
22e2c507 JA |
1109 | cfqq = cfqd->active_queue; |
1110 | if (!cfqq) | |
1111 | goto new_queue; | |
1da177e4 | 1112 | |
3b18152c JA |
1113 | if (cfq_cfqq_expired(cfqq)) |
1114 | goto new_queue; | |
1115 | ||
22e2c507 JA |
1116 | /* |
1117 | * slice has expired | |
1118 | */ | |
3b18152c JA |
1119 | if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) |
1120 | goto expire; | |
1da177e4 | 1121 | |
22e2c507 JA |
1122 | /* |
1123 | * if queue has requests, dispatch one. if not, check if | |
1124 | * enough slice is left to wait for one | |
1125 | */ | |
1126 | if (!RB_EMPTY(&cfqq->sort_list)) | |
1127 | goto keep_queue; | |
3b18152c | 1128 | else if (!force && cfq_cfqq_class_sync(cfqq) && |
22e2c507 JA |
1129 | time_before(now, cfqq->slice_end)) { |
1130 | if (cfq_arm_slice_timer(cfqd, cfqq)) | |
1131 | return NULL; | |
1132 | } | |
1133 | ||
3b18152c | 1134 | expire: |
22e2c507 | 1135 | cfq_slice_expired(cfqd, 0); |
3b18152c JA |
1136 | new_queue: |
1137 | cfqq = cfq_set_active_queue(cfqd); | |
22e2c507 | 1138 | keep_queue: |
3b18152c | 1139 | return cfqq; |
22e2c507 JA |
1140 | } |
1141 | ||
1142 | static int | |
1143 | __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1144 | int max_dispatch) | |
1145 | { | |
1146 | int dispatched = 0; | |
1147 | ||
1148 | BUG_ON(RB_EMPTY(&cfqq->sort_list)); | |
1149 | ||
1150 | do { | |
1151 | struct cfq_rq *crq; | |
1da177e4 LT |
1152 | |
1153 | /* | |
22e2c507 | 1154 | * follow expired path, else get first next available |
1da177e4 | 1155 | */ |
22e2c507 JA |
1156 | if ((crq = cfq_check_fifo(cfqq)) == NULL) |
1157 | crq = cfqq->next_crq; | |
1158 | ||
1159 | /* | |
1160 | * finally, insert request into driver dispatch list | |
1161 | */ | |
1162 | cfq_dispatch_sort(cfqd->queue, crq); | |
1da177e4 | 1163 | |
22e2c507 JA |
1164 | cfqd->dispatch_slice++; |
1165 | dispatched++; | |
1da177e4 | 1166 | |
22e2c507 JA |
1167 | if (!cfqd->active_cic) { |
1168 | atomic_inc(&crq->io_context->ioc->refcount); | |
1169 | cfqd->active_cic = crq->io_context; | |
1170 | } | |
1da177e4 | 1171 | |
22e2c507 JA |
1172 | if (RB_EMPTY(&cfqq->sort_list)) |
1173 | break; | |
1174 | ||
1175 | } while (dispatched < max_dispatch); | |
1176 | ||
1177 | /* | |
1178 | * if slice end isn't set yet, set it. if at least one request was | |
1179 | * sync, use the sync time slice value | |
1180 | */ | |
1181 | if (!cfqq->slice_end) | |
1182 | cfq_set_prio_slice(cfqd, cfqq); | |
1183 | ||
1184 | /* | |
1185 | * expire an async queue immediately if it has used up its slice. idle | |
1186 | * queue always expire after 1 dispatch round. | |
1187 | */ | |
1188 | if ((!cfq_cfqq_sync(cfqq) && | |
1189 | cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || | |
1190 | cfq_class_idle(cfqq)) | |
1191 | cfq_slice_expired(cfqd, 0); | |
1192 | ||
1193 | return dispatched; | |
1194 | } | |
1195 | ||
1196 | static int | |
1197 | cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force) | |
1198 | { | |
1199 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1200 | struct cfq_queue *cfqq; | |
1201 | ||
1202 | if (!cfqd->busy_queues) | |
1203 | return 0; | |
1204 | ||
1205 | cfqq = cfq_select_queue(cfqd, force); | |
1206 | if (cfqq) { | |
3b18152c JA |
1207 | cfq_clear_cfqq_must_dispatch(cfqq); |
1208 | cfq_clear_cfqq_wait_request(cfqq); | |
22e2c507 JA |
1209 | del_timer(&cfqd->idle_slice_timer); |
1210 | ||
1211 | if (cfq_class_idle(cfqq)) | |
1212 | max_dispatch = 1; | |
1da177e4 | 1213 | |
22e2c507 | 1214 | return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
1da177e4 LT |
1215 | } |
1216 | ||
22e2c507 | 1217 | return 0; |
1da177e4 LT |
1218 | } |
1219 | ||
1220 | static inline void cfq_account_dispatch(struct cfq_rq *crq) | |
1221 | { | |
1222 | struct cfq_queue *cfqq = crq->cfq_queue; | |
1223 | struct cfq_data *cfqd = cfqq->cfqd; | |
1da177e4 | 1224 | |
22e2c507 | 1225 | if (unlikely(!blk_fs_request(crq->request))) |
1da177e4 LT |
1226 | return; |
1227 | ||
1228 | /* | |
1229 | * accounted bit is necessary since some drivers will call | |
1230 | * elv_next_request() many times for the same request (eg ide) | |
1231 | */ | |
3b18152c | 1232 | if (cfq_crq_in_driver(crq)) |
1da177e4 LT |
1233 | return; |
1234 | ||
3b18152c | 1235 | cfq_mark_crq_in_driver(crq); |
22e2c507 | 1236 | cfqd->rq_in_driver++; |
1da177e4 LT |
1237 | } |
1238 | ||
1239 | static inline void | |
1240 | cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq) | |
1241 | { | |
1242 | struct cfq_data *cfqd = cfqq->cfqd; | |
22e2c507 | 1243 | unsigned long now; |
1da177e4 | 1244 | |
3b18152c | 1245 | if (!cfq_crq_in_driver(crq)) |
1da177e4 LT |
1246 | return; |
1247 | ||
22e2c507 JA |
1248 | now = jiffies; |
1249 | ||
1da177e4 LT |
1250 | WARN_ON(!cfqd->rq_in_driver); |
1251 | cfqd->rq_in_driver--; | |
1252 | ||
22e2c507 JA |
1253 | if (!cfq_class_idle(cfqq)) |
1254 | cfqd->last_end_request = now; | |
1da177e4 | 1255 | |
3b18152c JA |
1256 | if (!cfq_cfqq_dispatched(cfqq)) { |
1257 | if (cfq_cfqq_on_rr(cfqq)) { | |
1258 | cfqq->service_last = now; | |
1259 | cfq_resort_rr_list(cfqq, 0); | |
1260 | } | |
1261 | if (cfq_cfqq_expired(cfqq)) { | |
1262 | __cfq_slice_expired(cfqd, cfqq, 0); | |
1263 | cfq_schedule_dispatch(cfqd); | |
1264 | } | |
1da177e4 | 1265 | } |
22e2c507 | 1266 | |
3b18152c | 1267 | if (cfq_crq_is_sync(crq)) |
22e2c507 | 1268 | crq->io_context->last_end_request = now; |
1da177e4 LT |
1269 | } |
1270 | ||
1271 | static struct request *cfq_next_request(request_queue_t *q) | |
1272 | { | |
1273 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1274 | struct request *rq; | |
1275 | ||
1276 | if (!list_empty(&q->queue_head)) { | |
1277 | struct cfq_rq *crq; | |
1278 | dispatch: | |
1279 | rq = list_entry_rq(q->queue_head.next); | |
1280 | ||
22e2c507 JA |
1281 | crq = RQ_DATA(rq); |
1282 | if (crq) { | |
3b18152c JA |
1283 | struct cfq_queue *cfqq = crq->cfq_queue; |
1284 | ||
22e2c507 JA |
1285 | /* |
1286 | * if idle window is disabled, allow queue buildup | |
1287 | */ | |
3b18152c JA |
1288 | if (!cfq_crq_in_driver(crq) && |
1289 | !cfq_cfqq_idle_window(cfqq) && | |
d7ed538a | 1290 | !blk_barrier_rq(rq) && |
22e2c507 JA |
1291 | cfqd->rq_in_driver >= cfqd->cfq_max_depth) |
1292 | return NULL; | |
1293 | ||
1da177e4 LT |
1294 | cfq_remove_merge_hints(q, crq); |
1295 | cfq_account_dispatch(crq); | |
1296 | } | |
1297 | ||
1298 | return rq; | |
1299 | } | |
1300 | ||
22e2c507 | 1301 | if (cfq_dispatch_requests(q, cfqd->cfq_quantum, 0)) |
1da177e4 LT |
1302 | goto dispatch; |
1303 | ||
1304 | return NULL; | |
1305 | } | |
1306 | ||
1307 | /* | |
1308 | * task holds one reference to the queue, dropped when task exits. each crq | |
1309 | * in-flight on this queue also holds a reference, dropped when crq is freed. | |
1310 | * | |
1311 | * queue lock must be held here. | |
1312 | */ | |
1313 | static void cfq_put_queue(struct cfq_queue *cfqq) | |
1314 | { | |
22e2c507 JA |
1315 | struct cfq_data *cfqd = cfqq->cfqd; |
1316 | ||
1317 | BUG_ON(atomic_read(&cfqq->ref) <= 0); | |
1da177e4 LT |
1318 | |
1319 | if (!atomic_dec_and_test(&cfqq->ref)) | |
1320 | return; | |
1321 | ||
1322 | BUG_ON(rb_first(&cfqq->sort_list)); | |
22e2c507 | 1323 | BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3b18152c | 1324 | BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4 | 1325 | |
22e2c507 | 1326 | if (unlikely(cfqd->active_queue == cfqq)) { |
3b18152c JA |
1327 | __cfq_slice_expired(cfqd, cfqq, 0); |
1328 | cfq_schedule_dispatch(cfqd); | |
22e2c507 JA |
1329 | } |
1330 | ||
1da177e4 LT |
1331 | cfq_put_cfqd(cfqq->cfqd); |
1332 | ||
1333 | /* | |
1334 | * it's on the empty list and still hashed | |
1335 | */ | |
1336 | list_del(&cfqq->cfq_list); | |
1337 | hlist_del(&cfqq->cfq_hash); | |
1338 | kmem_cache_free(cfq_pool, cfqq); | |
1339 | } | |
1340 | ||
1341 | static inline struct cfq_queue * | |
3b18152c JA |
1342 | __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, |
1343 | const int hashval) | |
1da177e4 LT |
1344 | { |
1345 | struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; | |
1346 | struct hlist_node *entry, *next; | |
1347 | ||
1348 | hlist_for_each_safe(entry, next, hash_list) { | |
1349 | struct cfq_queue *__cfqq = list_entry_qhash(entry); | |
3b18152c | 1350 | const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->ioprio_class, __cfqq->ioprio); |
1da177e4 | 1351 | |
3b18152c | 1352 | if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY)) |
1da177e4 LT |
1353 | return __cfqq; |
1354 | } | |
1355 | ||
1356 | return NULL; | |
1357 | } | |
1358 | ||
1359 | static struct cfq_queue * | |
3b18152c | 1360 | cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) |
1da177e4 | 1361 | { |
3b18152c | 1362 | return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); |
1da177e4 LT |
1363 | } |
1364 | ||
22e2c507 | 1365 | static void cfq_free_io_context(struct cfq_io_context *cic) |
1da177e4 | 1366 | { |
22e2c507 JA |
1367 | struct cfq_io_context *__cic; |
1368 | struct list_head *entry, *next; | |
1da177e4 | 1369 | |
22e2c507 JA |
1370 | list_for_each_safe(entry, next, &cic->list) { |
1371 | __cic = list_entry(entry, struct cfq_io_context, list); | |
1372 | kmem_cache_free(cfq_ioc_pool, __cic); | |
1da177e4 LT |
1373 | } |
1374 | ||
22e2c507 | 1375 | kmem_cache_free(cfq_ioc_pool, cic); |
1da177e4 LT |
1376 | } |
1377 | ||
22e2c507 JA |
1378 | /* |
1379 | * Called with interrupts disabled | |
1380 | */ | |
1381 | static void cfq_exit_single_io_context(struct cfq_io_context *cic) | |
1da177e4 | 1382 | { |
22e2c507 JA |
1383 | struct cfq_data *cfqd = cic->cfqq->cfqd; |
1384 | request_queue_t *q = cfqd->queue; | |
1385 | ||
1386 | WARN_ON(!irqs_disabled()); | |
1387 | ||
1388 | spin_lock(q->queue_lock); | |
1389 | ||
1390 | if (unlikely(cic->cfqq == cfqd->active_queue)) { | |
3b18152c JA |
1391 | __cfq_slice_expired(cfqd, cic->cfqq, 0); |
1392 | cfq_schedule_dispatch(cfqd); | |
22e2c507 JA |
1393 | } |
1394 | ||
1395 | cfq_put_queue(cic->cfqq); | |
1396 | cic->cfqq = NULL; | |
1397 | spin_unlock(q->queue_lock); | |
1da177e4 LT |
1398 | } |
1399 | ||
1400 | /* | |
22e2c507 JA |
1401 | * Another task may update the task cic list, if it is doing a queue lookup |
1402 | * on its behalf. cfq_cic_lock excludes such concurrent updates | |
1da177e4 LT |
1403 | */ |
1404 | static void cfq_exit_io_context(struct cfq_io_context *cic) | |
1405 | { | |
22e2c507 JA |
1406 | struct cfq_io_context *__cic; |
1407 | struct list_head *entry; | |
1da177e4 LT |
1408 | unsigned long flags; |
1409 | ||
22e2c507 JA |
1410 | local_irq_save(flags); |
1411 | ||
1da177e4 LT |
1412 | /* |
1413 | * put the reference this task is holding to the various queues | |
1414 | */ | |
22e2c507 | 1415 | list_for_each(entry, &cic->list) { |
1da177e4 | 1416 | __cic = list_entry(entry, struct cfq_io_context, list); |
22e2c507 | 1417 | cfq_exit_single_io_context(__cic); |
1da177e4 LT |
1418 | } |
1419 | ||
22e2c507 JA |
1420 | cfq_exit_single_io_context(cic); |
1421 | local_irq_restore(flags); | |
1da177e4 LT |
1422 | } |
1423 | ||
22e2c507 JA |
1424 | static struct cfq_io_context * |
1425 | cfq_alloc_io_context(struct cfq_data *cfqd, int gfp_mask) | |
1da177e4 | 1426 | { |
22e2c507 | 1427 | struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); |
1da177e4 LT |
1428 | |
1429 | if (cic) { | |
1da177e4 LT |
1430 | INIT_LIST_HEAD(&cic->list); |
1431 | cic->cfqq = NULL; | |
22e2c507 JA |
1432 | cic->key = NULL; |
1433 | cic->last_end_request = jiffies; | |
1434 | cic->ttime_total = 0; | |
1435 | cic->ttime_samples = 0; | |
1436 | cic->ttime_mean = 0; | |
1437 | cic->dtor = cfq_free_io_context; | |
1438 | cic->exit = cfq_exit_io_context; | |
1da177e4 LT |
1439 | } |
1440 | ||
1441 | return cic; | |
1442 | } | |
1443 | ||
22e2c507 JA |
1444 | static void cfq_init_prio_data(struct cfq_queue *cfqq) |
1445 | { | |
1446 | struct task_struct *tsk = current; | |
1447 | int ioprio_class; | |
1448 | ||
3b18152c | 1449 | if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507 JA |
1450 | return; |
1451 | ||
1452 | ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); | |
1453 | switch (ioprio_class) { | |
1454 | default: | |
1455 | printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); | |
1456 | case IOPRIO_CLASS_NONE: | |
1457 | /* | |
1458 | * no prio set, place us in the middle of the BE classes | |
1459 | */ | |
1460 | cfqq->ioprio = task_nice_ioprio(tsk); | |
1461 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1462 | break; | |
1463 | case IOPRIO_CLASS_RT: | |
1464 | cfqq->ioprio = task_ioprio(tsk); | |
1465 | cfqq->ioprio_class = IOPRIO_CLASS_RT; | |
1466 | break; | |
1467 | case IOPRIO_CLASS_BE: | |
1468 | cfqq->ioprio = task_ioprio(tsk); | |
1469 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1470 | break; | |
1471 | case IOPRIO_CLASS_IDLE: | |
1472 | cfqq->ioprio_class = IOPRIO_CLASS_IDLE; | |
1473 | cfqq->ioprio = 7; | |
3b18152c | 1474 | cfq_clear_cfqq_idle_window(cfqq); |
22e2c507 JA |
1475 | break; |
1476 | } | |
1477 | ||
1478 | /* | |
1479 | * keep track of original prio settings in case we have to temporarily | |
1480 | * elevate the priority of this queue | |
1481 | */ | |
1482 | cfqq->org_ioprio = cfqq->ioprio; | |
1483 | cfqq->org_ioprio_class = cfqq->ioprio_class; | |
1484 | ||
3b18152c | 1485 | if (cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1486 | cfq_resort_rr_list(cfqq, 0); |
1487 | ||
3b18152c | 1488 | cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507 JA |
1489 | } |
1490 | ||
1491 | static inline void changed_ioprio(struct cfq_queue *cfqq) | |
1492 | { | |
1493 | if (cfqq) { | |
1494 | struct cfq_data *cfqd = cfqq->cfqd; | |
1495 | ||
1496 | spin_lock(cfqd->queue->queue_lock); | |
3b18152c | 1497 | cfq_mark_cfqq_prio_changed(cfqq); |
22e2c507 JA |
1498 | cfq_init_prio_data(cfqq); |
1499 | spin_unlock(cfqd->queue->queue_lock); | |
1500 | } | |
1501 | } | |
1502 | ||
1503 | /* | |
1504 | * callback from sys_ioprio_set, irqs are disabled | |
1505 | */ | |
1506 | static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) | |
1507 | { | |
1508 | struct cfq_io_context *cic = ioc->cic; | |
1509 | ||
1510 | changed_ioprio(cic->cfqq); | |
1511 | ||
1512 | list_for_each_entry(cic, &cic->list, list) | |
1513 | changed_ioprio(cic->cfqq); | |
1514 | ||
1515 | return 0; | |
1516 | } | |
1517 | ||
1518 | static struct cfq_queue * | |
3b18152c JA |
1519 | cfq_get_queue(struct cfq_data *cfqd, unsigned int key, unsigned short ioprio, |
1520 | int gfp_mask) | |
22e2c507 JA |
1521 | { |
1522 | const int hashval = hash_long(key, CFQ_QHASH_SHIFT); | |
1523 | struct cfq_queue *cfqq, *new_cfqq = NULL; | |
1524 | ||
1525 | retry: | |
3b18152c | 1526 | cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); |
22e2c507 JA |
1527 | |
1528 | if (!cfqq) { | |
1529 | if (new_cfqq) { | |
1530 | cfqq = new_cfqq; | |
1531 | new_cfqq = NULL; | |
1532 | } else if (gfp_mask & __GFP_WAIT) { | |
1533 | spin_unlock_irq(cfqd->queue->queue_lock); | |
1534 | new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1535 | spin_lock_irq(cfqd->queue->queue_lock); | |
1536 | goto retry; | |
1537 | } else { | |
1538 | cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); | |
1539 | if (!cfqq) | |
1540 | goto out; | |
1541 | } | |
1542 | ||
1543 | memset(cfqq, 0, sizeof(*cfqq)); | |
1544 | ||
1545 | INIT_HLIST_NODE(&cfqq->cfq_hash); | |
1546 | INIT_LIST_HEAD(&cfqq->cfq_list); | |
1547 | RB_CLEAR_ROOT(&cfqq->sort_list); | |
1548 | INIT_LIST_HEAD(&cfqq->fifo); | |
1549 | ||
1550 | cfqq->key = key; | |
1551 | hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); | |
1552 | atomic_set(&cfqq->ref, 0); | |
1553 | cfqq->cfqd = cfqd; | |
1554 | atomic_inc(&cfqd->ref); | |
1555 | cfqq->service_last = 0; | |
1556 | /* | |
1557 | * set ->slice_left to allow preemption for a new process | |
1558 | */ | |
1559 | cfqq->slice_left = 2 * cfqd->cfq_slice_idle; | |
3b18152c JA |
1560 | cfq_mark_cfqq_idle_window(cfqq); |
1561 | cfq_mark_cfqq_prio_changed(cfqq); | |
1562 | cfq_init_prio_data(cfqq); | |
22e2c507 JA |
1563 | } |
1564 | ||
1565 | if (new_cfqq) | |
1566 | kmem_cache_free(cfq_pool, new_cfqq); | |
1567 | ||
1568 | atomic_inc(&cfqq->ref); | |
1569 | out: | |
1570 | WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); | |
1571 | return cfqq; | |
1572 | } | |
1573 | ||
1da177e4 LT |
1574 | /* |
1575 | * Setup general io context and cfq io context. There can be several cfq | |
1576 | * io contexts per general io context, if this process is doing io to more | |
1577 | * than one device managed by cfq. Note that caller is holding a reference to | |
1578 | * cfqq, so we don't need to worry about it disappearing | |
1579 | */ | |
1580 | static struct cfq_io_context * | |
22e2c507 | 1581 | cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, int gfp_mask) |
1da177e4 | 1582 | { |
22e2c507 | 1583 | struct io_context *ioc = NULL; |
1da177e4 | 1584 | struct cfq_io_context *cic; |
1da177e4 | 1585 | |
22e2c507 | 1586 | might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4 | 1587 | |
22e2c507 | 1588 | ioc = get_io_context(gfp_mask); |
1da177e4 LT |
1589 | if (!ioc) |
1590 | return NULL; | |
1591 | ||
1592 | if ((cic = ioc->cic) == NULL) { | |
22e2c507 | 1593 | cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4 LT |
1594 | |
1595 | if (cic == NULL) | |
1596 | goto err; | |
1597 | ||
22e2c507 JA |
1598 | /* |
1599 | * manually increment generic io_context usage count, it | |
1600 | * cannot go away since we are already holding one ref to it | |
1601 | */ | |
1da177e4 | 1602 | ioc->cic = cic; |
22e2c507 | 1603 | ioc->set_ioprio = cfq_ioc_set_ioprio; |
1da177e4 | 1604 | cic->ioc = ioc; |
22e2c507 JA |
1605 | cic->key = cfqd; |
1606 | atomic_inc(&cfqd->ref); | |
1da177e4 LT |
1607 | } else { |
1608 | struct cfq_io_context *__cic; | |
1da177e4 LT |
1609 | |
1610 | /* | |
22e2c507 | 1611 | * the first cic on the list is actually the head itself |
1da177e4 | 1612 | */ |
22e2c507 | 1613 | if (cic->key == cfqd) |
1da177e4 LT |
1614 | goto out; |
1615 | ||
1616 | /* | |
1617 | * cic exists, check if we already are there. linear search | |
1618 | * should be ok here, the list will usually not be more than | |
1619 | * 1 or a few entries long | |
1620 | */ | |
1da177e4 LT |
1621 | list_for_each_entry(__cic, &cic->list, list) { |
1622 | /* | |
1623 | * this process is already holding a reference to | |
1624 | * this queue, so no need to get one more | |
1625 | */ | |
22e2c507 | 1626 | if (__cic->key == cfqd) { |
1da177e4 | 1627 | cic = __cic; |
1da177e4 LT |
1628 | goto out; |
1629 | } | |
1630 | } | |
1da177e4 LT |
1631 | |
1632 | /* | |
1633 | * nope, process doesn't have a cic assoicated with this | |
1634 | * cfqq yet. get a new one and add to list | |
1635 | */ | |
22e2c507 | 1636 | __cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4 LT |
1637 | if (__cic == NULL) |
1638 | goto err; | |
1639 | ||
1640 | __cic->ioc = ioc; | |
22e2c507 JA |
1641 | __cic->key = cfqd; |
1642 | atomic_inc(&cfqd->ref); | |
1da177e4 | 1643 | list_add(&__cic->list, &cic->list); |
1da177e4 | 1644 | cic = __cic; |
1da177e4 LT |
1645 | } |
1646 | ||
1647 | out: | |
1da177e4 LT |
1648 | return cic; |
1649 | err: | |
1650 | put_io_context(ioc); | |
1651 | return NULL; | |
1652 | } | |
1653 | ||
22e2c507 JA |
1654 | static void |
1655 | cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) | |
1da177e4 | 1656 | { |
22e2c507 | 1657 | unsigned long elapsed, ttime; |
1da177e4 | 1658 | |
22e2c507 JA |
1659 | /* |
1660 | * if this context already has stuff queued, thinktime is from | |
1661 | * last queue not last end | |
1662 | */ | |
1663 | #if 0 | |
1664 | if (time_after(cic->last_end_request, cic->last_queue)) | |
1665 | elapsed = jiffies - cic->last_end_request; | |
1666 | else | |
1667 | elapsed = jiffies - cic->last_queue; | |
1668 | #else | |
1669 | elapsed = jiffies - cic->last_end_request; | |
1670 | #endif | |
1da177e4 | 1671 | |
22e2c507 | 1672 | ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
db3b5848 | 1673 | |
22e2c507 JA |
1674 | cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; |
1675 | cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; | |
1676 | cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; | |
1677 | } | |
1da177e4 | 1678 | |
22e2c507 | 1679 | #define sample_valid(samples) ((samples) > 80) |
1da177e4 | 1680 | |
22e2c507 JA |
1681 | /* |
1682 | * Disable idle window if the process thinks too long or seeks so much that | |
1683 | * it doesn't matter | |
1684 | */ | |
1685 | static void | |
1686 | cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1687 | struct cfq_io_context *cic) | |
1688 | { | |
3b18152c | 1689 | int enable_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4 | 1690 | |
22e2c507 JA |
1691 | if (!cic->ioc->task || !cfqd->cfq_slice_idle) |
1692 | enable_idle = 0; | |
1693 | else if (sample_valid(cic->ttime_samples)) { | |
1694 | if (cic->ttime_mean > cfqd->cfq_slice_idle) | |
1695 | enable_idle = 0; | |
1696 | else | |
1697 | enable_idle = 1; | |
1da177e4 LT |
1698 | } |
1699 | ||
3b18152c JA |
1700 | if (enable_idle) |
1701 | cfq_mark_cfqq_idle_window(cfqq); | |
1702 | else | |
1703 | cfq_clear_cfqq_idle_window(cfqq); | |
22e2c507 | 1704 | } |
1da177e4 | 1705 | |
22e2c507 JA |
1706 | |
1707 | /* | |
1708 | * Check if new_cfqq should preempt the currently active queue. Return 0 for | |
1709 | * no or if we aren't sure, a 1 will cause a preempt. | |
1710 | */ | |
1711 | static int | |
1712 | cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, | |
1713 | struct cfq_rq *crq) | |
1714 | { | |
1715 | struct cfq_queue *cfqq = cfqd->active_queue; | |
1716 | ||
1717 | if (cfq_class_idle(new_cfqq)) | |
1718 | return 0; | |
1719 | ||
1720 | if (!cfqq) | |
1721 | return 1; | |
1722 | ||
1723 | if (cfq_class_idle(cfqq)) | |
1724 | return 1; | |
3b18152c | 1725 | if (!cfq_cfqq_wait_request(new_cfqq)) |
22e2c507 JA |
1726 | return 0; |
1727 | /* | |
1728 | * if it doesn't have slice left, forget it | |
1729 | */ | |
1730 | if (new_cfqq->slice_left < cfqd->cfq_slice_idle) | |
1731 | return 0; | |
3b18152c | 1732 | if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq)) |
22e2c507 JA |
1733 | return 1; |
1734 | ||
1735 | return 0; | |
1736 | } | |
1737 | ||
1738 | /* | |
1739 | * cfqq preempts the active queue. if we allowed preempt with no slice left, | |
1740 | * let it have half of its nominal slice. | |
1741 | */ | |
1742 | static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1743 | { | |
1744 | struct cfq_queue *__cfqq, *next; | |
1745 | ||
1746 | list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) | |
1747 | cfq_resort_rr_list(__cfqq, 1); | |
1748 | ||
1749 | if (!cfqq->slice_left) | |
1750 | cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; | |
1751 | ||
1752 | cfqq->slice_end = cfqq->slice_left + jiffies; | |
3b18152c | 1753 | __cfq_slice_expired(cfqd, cfqq, 1); |
22e2c507 JA |
1754 | __cfq_set_active_queue(cfqd, cfqq); |
1755 | } | |
1756 | ||
1757 | /* | |
1758 | * should really be a ll_rw_blk.c helper | |
1759 | */ | |
1760 | static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) | |
1761 | { | |
1762 | request_queue_t *q = cfqd->queue; | |
1763 | ||
1764 | if (!blk_queue_plugged(q)) | |
1765 | q->request_fn(q); | |
1766 | else | |
1767 | __generic_unplug_device(q); | |
1768 | } | |
1769 | ||
1770 | /* | |
1771 | * Called when a new fs request (crq) is added (to cfqq). Check if there's | |
1772 | * something we should do about it | |
1773 | */ | |
1774 | static void | |
1775 | cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1776 | struct cfq_rq *crq) | |
1777 | { | |
9c2c38a1 | 1778 | struct cfq_io_context *cic; |
22e2c507 JA |
1779 | |
1780 | cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); | |
1781 | ||
9c2c38a1 JA |
1782 | /* |
1783 | * we never wait for an async request and we don't allow preemption | |
1784 | * of an async request. so just return early | |
1785 | */ | |
1786 | if (!cfq_crq_is_sync(crq)) | |
1787 | return; | |
22e2c507 | 1788 | |
9c2c38a1 | 1789 | cic = crq->io_context; |
22e2c507 | 1790 | |
9c2c38a1 JA |
1791 | cfq_update_io_thinktime(cfqd, cic); |
1792 | cfq_update_idle_window(cfqd, cfqq, cic); | |
1793 | ||
1794 | cic->last_queue = jiffies; | |
22e2c507 JA |
1795 | |
1796 | if (cfqq == cfqd->active_queue) { | |
1797 | /* | |
1798 | * if we are waiting for a request for this queue, let it rip | |
1799 | * immediately and flag that we must not expire this queue | |
1800 | * just now | |
1801 | */ | |
3b18152c JA |
1802 | if (cfq_cfqq_wait_request(cfqq)) { |
1803 | cfq_mark_cfqq_must_dispatch(cfqq); | |
22e2c507 JA |
1804 | del_timer(&cfqd->idle_slice_timer); |
1805 | cfq_start_queueing(cfqd, cfqq); | |
1806 | } | |
1807 | } else if (cfq_should_preempt(cfqd, cfqq, crq)) { | |
1808 | /* | |
1809 | * not the active queue - expire current slice if it is | |
1810 | * idle and has expired it's mean thinktime or this new queue | |
1811 | * has some old slice time left and is of higher priority | |
1812 | */ | |
1813 | cfq_preempt_queue(cfqd, cfqq); | |
3b18152c | 1814 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
1815 | cfq_start_queueing(cfqd, cfqq); |
1816 | } | |
1da177e4 LT |
1817 | } |
1818 | ||
22e2c507 | 1819 | static void cfq_enqueue(struct cfq_data *cfqd, struct request *rq) |
1da177e4 | 1820 | { |
22e2c507 JA |
1821 | struct cfq_rq *crq = RQ_DATA(rq); |
1822 | struct cfq_queue *cfqq = crq->cfq_queue; | |
1823 | ||
1824 | cfq_init_prio_data(cfqq); | |
1da177e4 LT |
1825 | |
1826 | cfq_add_crq_rb(crq); | |
1da177e4 | 1827 | |
22e2c507 JA |
1828 | list_add_tail(&rq->queuelist, &cfqq->fifo); |
1829 | ||
1830 | if (rq_mergeable(rq)) { | |
1831 | cfq_add_crq_hash(cfqd, crq); | |
1832 | ||
1833 | if (!cfqd->queue->last_merge) | |
1834 | cfqd->queue->last_merge = rq; | |
1835 | } | |
1836 | ||
1837 | cfq_crq_enqueued(cfqd, cfqq, crq); | |
1da177e4 LT |
1838 | } |
1839 | ||
1840 | static void | |
1841 | cfq_insert_request(request_queue_t *q, struct request *rq, int where) | |
1842 | { | |
1843 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
1da177e4 LT |
1844 | |
1845 | switch (where) { | |
1846 | case ELEVATOR_INSERT_BACK: | |
22e2c507 | 1847 | while (cfq_dispatch_requests(q, INT_MAX, 1)) |
1da177e4 LT |
1848 | ; |
1849 | list_add_tail(&rq->queuelist, &q->queue_head); | |
22e2c507 JA |
1850 | /* |
1851 | * If we were idling with pending requests on | |
1852 | * inactive cfqqs, force dispatching will | |
1853 | * remove the idle timer and the queue won't | |
1854 | * be kicked by __make_request() afterward. | |
1855 | * Kick it here. | |
1856 | */ | |
3b18152c | 1857 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
1858 | break; |
1859 | case ELEVATOR_INSERT_FRONT: | |
1860 | list_add(&rq->queuelist, &q->queue_head); | |
1861 | break; | |
1862 | case ELEVATOR_INSERT_SORT: | |
1863 | BUG_ON(!blk_fs_request(rq)); | |
22e2c507 | 1864 | cfq_enqueue(cfqd, rq); |
1da177e4 LT |
1865 | break; |
1866 | default: | |
1867 | printk("%s: bad insert point %d\n", __FUNCTION__,where); | |
1868 | return; | |
1869 | } | |
22e2c507 | 1870 | } |
1da177e4 | 1871 | |
1da177e4 LT |
1872 | static void cfq_completed_request(request_queue_t *q, struct request *rq) |
1873 | { | |
1874 | struct cfq_rq *crq = RQ_DATA(rq); | |
1875 | struct cfq_queue *cfqq; | |
1876 | ||
1877 | if (unlikely(!blk_fs_request(rq))) | |
1878 | return; | |
1879 | ||
1880 | cfqq = crq->cfq_queue; | |
1881 | ||
3b18152c JA |
1882 | if (cfq_crq_in_flight(crq)) { |
1883 | const int sync = cfq_crq_is_sync(crq); | |
1884 | ||
1885 | WARN_ON(!cfqq->on_dispatch[sync]); | |
1886 | cfqq->on_dispatch[sync]--; | |
1da177e4 LT |
1887 | } |
1888 | ||
1889 | cfq_account_completion(cfqq, crq); | |
1890 | } | |
1891 | ||
1892 | static struct request * | |
1893 | cfq_former_request(request_queue_t *q, struct request *rq) | |
1894 | { | |
1895 | struct cfq_rq *crq = RQ_DATA(rq); | |
1896 | struct rb_node *rbprev = rb_prev(&crq->rb_node); | |
1897 | ||
1898 | if (rbprev) | |
1899 | return rb_entry_crq(rbprev)->request; | |
1900 | ||
1901 | return NULL; | |
1902 | } | |
1903 | ||
1904 | static struct request * | |
1905 | cfq_latter_request(request_queue_t *q, struct request *rq) | |
1906 | { | |
1907 | struct cfq_rq *crq = RQ_DATA(rq); | |
1908 | struct rb_node *rbnext = rb_next(&crq->rb_node); | |
1909 | ||
1910 | if (rbnext) | |
1911 | return rb_entry_crq(rbnext)->request; | |
1912 | ||
1913 | return NULL; | |
1914 | } | |
1915 | ||
22e2c507 JA |
1916 | /* |
1917 | * we temporarily boost lower priority queues if they are holding fs exclusive | |
1918 | * resources. they are boosted to normal prio (CLASS_BE/4) | |
1919 | */ | |
1920 | static void cfq_prio_boost(struct cfq_queue *cfqq) | |
1da177e4 | 1921 | { |
22e2c507 JA |
1922 | const int ioprio_class = cfqq->ioprio_class; |
1923 | const int ioprio = cfqq->ioprio; | |
1da177e4 | 1924 | |
22e2c507 JA |
1925 | if (has_fs_excl()) { |
1926 | /* | |
1927 | * boost idle prio on transactions that would lock out other | |
1928 | * users of the filesystem | |
1929 | */ | |
1930 | if (cfq_class_idle(cfqq)) | |
1931 | cfqq->ioprio_class = IOPRIO_CLASS_BE; | |
1932 | if (cfqq->ioprio > IOPRIO_NORM) | |
1933 | cfqq->ioprio = IOPRIO_NORM; | |
1934 | } else { | |
1935 | /* | |
1936 | * check if we need to unboost the queue | |
1937 | */ | |
1938 | if (cfqq->ioprio_class != cfqq->org_ioprio_class) | |
1939 | cfqq->ioprio_class = cfqq->org_ioprio_class; | |
1940 | if (cfqq->ioprio != cfqq->org_ioprio) | |
1941 | cfqq->ioprio = cfqq->org_ioprio; | |
1942 | } | |
1da177e4 | 1943 | |
22e2c507 JA |
1944 | /* |
1945 | * refile between round-robin lists if we moved the priority class | |
1946 | */ | |
1947 | if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && | |
3b18152c | 1948 | cfq_cfqq_on_rr(cfqq)) |
22e2c507 JA |
1949 | cfq_resort_rr_list(cfqq, 0); |
1950 | } | |
1da177e4 | 1951 | |
22e2c507 JA |
1952 | static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
1953 | { | |
1954 | if (rw == READ || process_sync(task)) | |
1955 | return task->pid; | |
1da177e4 | 1956 | |
22e2c507 JA |
1957 | return CFQ_KEY_ASYNC; |
1958 | } | |
1da177e4 | 1959 | |
22e2c507 JA |
1960 | static inline int |
1961 | __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, | |
1962 | struct task_struct *task, int rw) | |
1963 | { | |
3b18152c JA |
1964 | #if 1 |
1965 | if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && | |
99f95e52 | 1966 | !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1967 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1968 | return ELV_MQUEUE_MUST; |
3b18152c | 1969 | } |
1da177e4 | 1970 | |
22e2c507 | 1971 | return ELV_MQUEUE_MAY; |
3b18152c | 1972 | #else |
22e2c507 JA |
1973 | if (!cfqq || task->flags & PF_MEMALLOC) |
1974 | return ELV_MQUEUE_MAY; | |
3b18152c JA |
1975 | if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) { |
1976 | if (cfq_cfqq_wait_request(cfqq)) | |
22e2c507 | 1977 | return ELV_MQUEUE_MUST; |
1da177e4 | 1978 | |
22e2c507 JA |
1979 | /* |
1980 | * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we | |
1981 | * can quickly flood the queue with writes from a single task | |
1982 | */ | |
99f95e52 | 1983 | if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c | 1984 | cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507 | 1985 | return ELV_MQUEUE_MUST; |
1da177e4 | 1986 | } |
22e2c507 JA |
1987 | |
1988 | return ELV_MQUEUE_MAY; | |
1da177e4 | 1989 | } |
22e2c507 JA |
1990 | if (cfq_class_idle(cfqq)) |
1991 | return ELV_MQUEUE_NO; | |
1992 | if (cfqq->allocated[rw] >= cfqd->max_queued) { | |
1993 | struct io_context *ioc = get_io_context(GFP_ATOMIC); | |
1994 | int ret = ELV_MQUEUE_NO; | |
1da177e4 | 1995 | |
22e2c507 JA |
1996 | if (ioc && ioc->nr_batch_requests) |
1997 | ret = ELV_MQUEUE_MAY; | |
1998 | ||
1999 | put_io_context(ioc); | |
2000 | return ret; | |
2001 | } | |
2002 | ||
2003 | return ELV_MQUEUE_MAY; | |
2004 | #endif | |
2005 | } | |
2006 | ||
2007 | static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) | |
2008 | { | |
2009 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2010 | struct task_struct *tsk = current; | |
2011 | struct cfq_queue *cfqq; | |
2012 | ||
2013 | /* | |
2014 | * don't force setup of a queue from here, as a call to may_queue | |
2015 | * does not necessarily imply that a request actually will be queued. | |
2016 | * so just lookup a possibly existing queue, or return 'may queue' | |
2017 | * if that fails | |
2018 | */ | |
3b18152c | 2019 | cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); |
22e2c507 JA |
2020 | if (cfqq) { |
2021 | cfq_init_prio_data(cfqq); | |
2022 | cfq_prio_boost(cfqq); | |
2023 | ||
2024 | return __cfq_may_queue(cfqd, cfqq, tsk, rw); | |
2025 | } | |
2026 | ||
2027 | return ELV_MQUEUE_MAY; | |
1da177e4 LT |
2028 | } |
2029 | ||
2030 | static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) | |
2031 | { | |
22e2c507 | 2032 | struct cfq_data *cfqd = q->elevator->elevator_data; |
1da177e4 | 2033 | struct request_list *rl = &q->rq; |
1da177e4 | 2034 | |
22e2c507 JA |
2035 | if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) { |
2036 | smp_mb(); | |
2037 | if (waitqueue_active(&rl->wait[READ])) | |
2038 | wake_up(&rl->wait[READ]); | |
2039 | } | |
2040 | ||
2041 | if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) { | |
2042 | smp_mb(); | |
2043 | if (waitqueue_active(&rl->wait[WRITE])) | |
2044 | wake_up(&rl->wait[WRITE]); | |
2045 | } | |
1da177e4 LT |
2046 | } |
2047 | ||
2048 | /* | |
2049 | * queue lock held here | |
2050 | */ | |
2051 | static void cfq_put_request(request_queue_t *q, struct request *rq) | |
2052 | { | |
2053 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2054 | struct cfq_rq *crq = RQ_DATA(rq); | |
2055 | ||
2056 | if (crq) { | |
2057 | struct cfq_queue *cfqq = crq->cfq_queue; | |
22e2c507 | 2058 | const int rw = rq_data_dir(rq); |
1da177e4 | 2059 | |
22e2c507 JA |
2060 | BUG_ON(!cfqq->allocated[rw]); |
2061 | cfqq->allocated[rw]--; | |
1da177e4 | 2062 | |
22e2c507 | 2063 | put_io_context(crq->io_context->ioc); |
1da177e4 LT |
2064 | |
2065 | mempool_free(crq, cfqd->crq_pool); | |
2066 | rq->elevator_private = NULL; | |
2067 | ||
1da177e4 LT |
2068 | cfq_check_waiters(q, cfqq); |
2069 | cfq_put_queue(cfqq); | |
2070 | } | |
2071 | } | |
2072 | ||
2073 | /* | |
22e2c507 | 2074 | * Allocate cfq data structures associated with this request. |
1da177e4 | 2075 | */ |
22e2c507 JA |
2076 | static int |
2077 | cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, | |
2078 | int gfp_mask) | |
1da177e4 LT |
2079 | { |
2080 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
3b18152c | 2081 | struct task_struct *tsk = current; |
1da177e4 LT |
2082 | struct cfq_io_context *cic; |
2083 | const int rw = rq_data_dir(rq); | |
3b18152c | 2084 | pid_t key = cfq_queue_pid(tsk, rw); |
22e2c507 | 2085 | struct cfq_queue *cfqq; |
1da177e4 LT |
2086 | struct cfq_rq *crq; |
2087 | unsigned long flags; | |
2088 | ||
2089 | might_sleep_if(gfp_mask & __GFP_WAIT); | |
2090 | ||
3b18152c | 2091 | cic = cfq_get_io_context(cfqd, key, gfp_mask); |
22e2c507 | 2092 | |
1da177e4 LT |
2093 | spin_lock_irqsave(q->queue_lock, flags); |
2094 | ||
22e2c507 JA |
2095 | if (!cic) |
2096 | goto queue_fail; | |
2097 | ||
2098 | if (!cic->cfqq) { | |
3b18152c | 2099 | cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask); |
22e2c507 JA |
2100 | if (!cfqq) |
2101 | goto queue_fail; | |
1da177e4 | 2102 | |
22e2c507 JA |
2103 | cic->cfqq = cfqq; |
2104 | } else | |
2105 | cfqq = cic->cfqq; | |
1da177e4 LT |
2106 | |
2107 | cfqq->allocated[rw]++; | |
3b18152c | 2108 | cfq_clear_cfqq_must_alloc(cfqq); |
22e2c507 JA |
2109 | cfqd->rq_starved = 0; |
2110 | atomic_inc(&cfqq->ref); | |
1da177e4 LT |
2111 | spin_unlock_irqrestore(q->queue_lock, flags); |
2112 | ||
1da177e4 LT |
2113 | crq = mempool_alloc(cfqd->crq_pool, gfp_mask); |
2114 | if (crq) { | |
2115 | RB_CLEAR(&crq->rb_node); | |
2116 | crq->rb_key = 0; | |
2117 | crq->request = rq; | |
2118 | INIT_HLIST_NODE(&crq->hash); | |
2119 | crq->cfq_queue = cfqq; | |
2120 | crq->io_context = cic; | |
3b18152c JA |
2121 | cfq_clear_crq_in_flight(crq); |
2122 | cfq_clear_crq_in_driver(crq); | |
2123 | cfq_clear_crq_requeued(crq); | |
2124 | ||
2125 | if (rw == READ || process_sync(tsk)) | |
2126 | cfq_mark_crq_is_sync(crq); | |
2127 | else | |
2128 | cfq_clear_crq_is_sync(crq); | |
2129 | ||
1da177e4 | 2130 | rq->elevator_private = crq; |
1da177e4 LT |
2131 | return 0; |
2132 | } | |
2133 | ||
1da177e4 LT |
2134 | spin_lock_irqsave(q->queue_lock, flags); |
2135 | cfqq->allocated[rw]--; | |
22e2c507 | 2136 | if (!(cfqq->allocated[0] + cfqq->allocated[1])) |
3b18152c | 2137 | cfq_mark_cfqq_must_alloc(cfqq); |
1da177e4 | 2138 | cfq_put_queue(cfqq); |
22e2c507 JA |
2139 | queue_fail: |
2140 | if (cic) | |
2141 | put_io_context(cic->ioc); | |
2142 | /* | |
2143 | * mark us rq allocation starved. we need to kickstart the process | |
2144 | * ourselves if there are no pending requests that can do it for us. | |
2145 | * that would be an extremely rare OOM situation | |
2146 | */ | |
2147 | cfqd->rq_starved = 1; | |
3b18152c | 2148 | cfq_schedule_dispatch(cfqd); |
1da177e4 LT |
2149 | spin_unlock_irqrestore(q->queue_lock, flags); |
2150 | return 1; | |
2151 | } | |
2152 | ||
22e2c507 JA |
2153 | static void cfq_kick_queue(void *data) |
2154 | { | |
2155 | request_queue_t *q = data; | |
2156 | struct cfq_data *cfqd = q->elevator->elevator_data; | |
2157 | unsigned long flags; | |
2158 | ||
2159 | spin_lock_irqsave(q->queue_lock, flags); | |
2160 | ||
2161 | if (cfqd->rq_starved) { | |
2162 | struct request_list *rl = &q->rq; | |
2163 | ||
2164 | /* | |
2165 | * we aren't guaranteed to get a request after this, but we | |
2166 | * have to be opportunistic | |
2167 | */ | |
2168 | smp_mb(); | |
2169 | if (waitqueue_active(&rl->wait[READ])) | |
2170 | wake_up(&rl->wait[READ]); | |
2171 | if (waitqueue_active(&rl->wait[WRITE])) | |
2172 | wake_up(&rl->wait[WRITE]); | |
2173 | } | |
2174 | ||
2175 | blk_remove_plug(q); | |
2176 | q->request_fn(q); | |
2177 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2178 | } | |
2179 | ||
2180 | /* | |
2181 | * Timer running if the active_queue is currently idling inside its time slice | |
2182 | */ | |
2183 | static void cfq_idle_slice_timer(unsigned long data) | |
2184 | { | |
2185 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2186 | struct cfq_queue *cfqq; | |
2187 | unsigned long flags; | |
2188 | ||
2189 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2190 | ||
2191 | if ((cfqq = cfqd->active_queue) != NULL) { | |
2192 | unsigned long now = jiffies; | |
2193 | ||
2194 | /* | |
2195 | * expired | |
2196 | */ | |
2197 | if (time_after(now, cfqq->slice_end)) | |
2198 | goto expire; | |
2199 | ||
2200 | /* | |
2201 | * only expire and reinvoke request handler, if there are | |
2202 | * other queues with pending requests | |
2203 | */ | |
2204 | if (!cfq_pending_requests(cfqd)) { | |
2205 | cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end); | |
2206 | add_timer(&cfqd->idle_slice_timer); | |
2207 | goto out_cont; | |
2208 | } | |
2209 | ||
2210 | /* | |
2211 | * not expired and it has a request pending, let it dispatch | |
2212 | */ | |
2213 | if (!RB_EMPTY(&cfqq->sort_list)) { | |
3b18152c | 2214 | cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507 JA |
2215 | goto out_kick; |
2216 | } | |
2217 | } | |
2218 | expire: | |
2219 | cfq_slice_expired(cfqd, 0); | |
2220 | out_kick: | |
3b18152c | 2221 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2222 | out_cont: |
2223 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2224 | } | |
2225 | ||
2226 | /* | |
2227 | * Timer running if an idle class queue is waiting for service | |
2228 | */ | |
2229 | static void cfq_idle_class_timer(unsigned long data) | |
2230 | { | |
2231 | struct cfq_data *cfqd = (struct cfq_data *) data; | |
2232 | unsigned long flags, end; | |
2233 | ||
2234 | spin_lock_irqsave(cfqd->queue->queue_lock, flags); | |
2235 | ||
2236 | /* | |
2237 | * race with a non-idle queue, reset timer | |
2238 | */ | |
2239 | end = cfqd->last_end_request + CFQ_IDLE_GRACE; | |
2240 | if (!time_after_eq(jiffies, end)) { | |
2241 | cfqd->idle_class_timer.expires = end; | |
2242 | add_timer(&cfqd->idle_class_timer); | |
2243 | } else | |
3b18152c | 2244 | cfq_schedule_dispatch(cfqd); |
22e2c507 JA |
2245 | |
2246 | spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); | |
2247 | } | |
2248 | ||
3b18152c JA |
2249 | static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) |
2250 | { | |
2251 | del_timer_sync(&cfqd->idle_slice_timer); | |
2252 | del_timer_sync(&cfqd->idle_class_timer); | |
2253 | blk_sync_queue(cfqd->queue); | |
2254 | } | |
22e2c507 | 2255 | |
1da177e4 LT |
2256 | static void cfq_put_cfqd(struct cfq_data *cfqd) |
2257 | { | |
2258 | request_queue_t *q = cfqd->queue; | |
2259 | ||
2260 | if (!atomic_dec_and_test(&cfqd->ref)) | |
2261 | return; | |
2262 | ||
96c51ce9 JA |
2263 | cfq_shutdown_timer_wq(cfqd); |
2264 | q->elevator->elevator_data = NULL; | |
2265 | ||
1da177e4 LT |
2266 | mempool_destroy(cfqd->crq_pool); |
2267 | kfree(cfqd->crq_hash); | |
2268 | kfree(cfqd->cfq_hash); | |
2269 | kfree(cfqd); | |
2270 | } | |
2271 | ||
2272 | static void cfq_exit_queue(elevator_t *e) | |
2273 | { | |
22e2c507 JA |
2274 | struct cfq_data *cfqd = e->elevator_data; |
2275 | ||
3b18152c | 2276 | cfq_shutdown_timer_wq(cfqd); |
22e2c507 | 2277 | cfq_put_cfqd(cfqd); |
1da177e4 LT |
2278 | } |
2279 | ||
2280 | static int cfq_init_queue(request_queue_t *q, elevator_t *e) | |
2281 | { | |
2282 | struct cfq_data *cfqd; | |
2283 | int i; | |
2284 | ||
2285 | cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); | |
2286 | if (!cfqd) | |
2287 | return -ENOMEM; | |
2288 | ||
2289 | memset(cfqd, 0, sizeof(*cfqd)); | |
22e2c507 JA |
2290 | |
2291 | for (i = 0; i < CFQ_PRIO_LISTS; i++) | |
2292 | INIT_LIST_HEAD(&cfqd->rr_list[i]); | |
2293 | ||
2294 | INIT_LIST_HEAD(&cfqd->busy_rr); | |
2295 | INIT_LIST_HEAD(&cfqd->cur_rr); | |
2296 | INIT_LIST_HEAD(&cfqd->idle_rr); | |
1da177e4 LT |
2297 | INIT_LIST_HEAD(&cfqd->empty_list); |
2298 | ||
2299 | cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); | |
2300 | if (!cfqd->crq_hash) | |
2301 | goto out_crqhash; | |
2302 | ||
2303 | cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); | |
2304 | if (!cfqd->cfq_hash) | |
2305 | goto out_cfqhash; | |
2306 | ||
2307 | cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool); | |
2308 | if (!cfqd->crq_pool) | |
2309 | goto out_crqpool; | |
2310 | ||
2311 | for (i = 0; i < CFQ_MHASH_ENTRIES; i++) | |
2312 | INIT_HLIST_HEAD(&cfqd->crq_hash[i]); | |
2313 | for (i = 0; i < CFQ_QHASH_ENTRIES; i++) | |
2314 | INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); | |
2315 | ||
2316 | e->elevator_data = cfqd; | |
2317 | ||
2318 | cfqd->queue = q; | |
1da177e4 | 2319 | |
22e2c507 | 2320 | cfqd->max_queued = q->nr_requests / 4; |
1da177e4 | 2321 | q->nr_batching = cfq_queued; |
22e2c507 JA |
2322 | |
2323 | init_timer(&cfqd->idle_slice_timer); | |
2324 | cfqd->idle_slice_timer.function = cfq_idle_slice_timer; | |
2325 | cfqd->idle_slice_timer.data = (unsigned long) cfqd; | |
2326 | ||
2327 | init_timer(&cfqd->idle_class_timer); | |
2328 | cfqd->idle_class_timer.function = cfq_idle_class_timer; | |
2329 | cfqd->idle_class_timer.data = (unsigned long) cfqd; | |
2330 | ||
2331 | INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); | |
2332 | ||
1da177e4 LT |
2333 | atomic_set(&cfqd->ref, 1); |
2334 | ||
2335 | cfqd->cfq_queued = cfq_queued; | |
2336 | cfqd->cfq_quantum = cfq_quantum; | |
22e2c507 JA |
2337 | cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; |
2338 | cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; | |
1da177e4 LT |
2339 | cfqd->cfq_back_max = cfq_back_max; |
2340 | cfqd->cfq_back_penalty = cfq_back_penalty; | |
22e2c507 JA |
2341 | cfqd->cfq_slice[0] = cfq_slice_async; |
2342 | cfqd->cfq_slice[1] = cfq_slice_sync; | |
2343 | cfqd->cfq_slice_async_rq = cfq_slice_async_rq; | |
2344 | cfqd->cfq_slice_idle = cfq_slice_idle; | |
2345 | cfqd->cfq_max_depth = cfq_max_depth; | |
3b18152c | 2346 | |
1da177e4 LT |
2347 | return 0; |
2348 | out_crqpool: | |
2349 | kfree(cfqd->cfq_hash); | |
2350 | out_cfqhash: | |
2351 | kfree(cfqd->crq_hash); | |
2352 | out_crqhash: | |
2353 | kfree(cfqd); | |
2354 | return -ENOMEM; | |
2355 | } | |
2356 | ||
2357 | static void cfq_slab_kill(void) | |
2358 | { | |
2359 | if (crq_pool) | |
2360 | kmem_cache_destroy(crq_pool); | |
2361 | if (cfq_pool) | |
2362 | kmem_cache_destroy(cfq_pool); | |
2363 | if (cfq_ioc_pool) | |
2364 | kmem_cache_destroy(cfq_ioc_pool); | |
2365 | } | |
2366 | ||
2367 | static int __init cfq_slab_setup(void) | |
2368 | { | |
2369 | crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, | |
2370 | NULL, NULL); | |
2371 | if (!crq_pool) | |
2372 | goto fail; | |
2373 | ||
2374 | cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, | |
2375 | NULL, NULL); | |
2376 | if (!cfq_pool) | |
2377 | goto fail; | |
2378 | ||
2379 | cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", | |
2380 | sizeof(struct cfq_io_context), 0, 0, NULL, NULL); | |
2381 | if (!cfq_ioc_pool) | |
2382 | goto fail; | |
2383 | ||
2384 | return 0; | |
2385 | fail: | |
2386 | cfq_slab_kill(); | |
2387 | return -ENOMEM; | |
2388 | } | |
2389 | ||
1da177e4 LT |
2390 | /* |
2391 | * sysfs parts below --> | |
2392 | */ | |
2393 | struct cfq_fs_entry { | |
2394 | struct attribute attr; | |
2395 | ssize_t (*show)(struct cfq_data *, char *); | |
2396 | ssize_t (*store)(struct cfq_data *, const char *, size_t); | |
2397 | }; | |
2398 | ||
2399 | static ssize_t | |
2400 | cfq_var_show(unsigned int var, char *page) | |
2401 | { | |
2402 | return sprintf(page, "%d\n", var); | |
2403 | } | |
2404 | ||
2405 | static ssize_t | |
2406 | cfq_var_store(unsigned int *var, const char *page, size_t count) | |
2407 | { | |
2408 | char *p = (char *) page; | |
2409 | ||
2410 | *var = simple_strtoul(p, &p, 10); | |
2411 | return count; | |
2412 | } | |
2413 | ||
1da177e4 LT |
2414 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ |
2415 | static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \ | |
2416 | { \ | |
2417 | unsigned int __data = __VAR; \ | |
2418 | if (__CONV) \ | |
2419 | __data = jiffies_to_msecs(__data); \ | |
2420 | return cfq_var_show(__data, (page)); \ | |
2421 | } | |
2422 | SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); | |
2423 | SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); | |
22e2c507 JA |
2424 | SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); |
2425 | SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); | |
1da177e4 LT |
2426 | SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); |
2427 | SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); | |
22e2c507 JA |
2428 | SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); |
2429 | SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); | |
2430 | SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); | |
2431 | SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); | |
2432 | SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0); | |
1da177e4 LT |
2433 | #undef SHOW_FUNCTION |
2434 | ||
2435 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
2436 | static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \ | |
2437 | { \ | |
2438 | unsigned int __data; \ | |
2439 | int ret = cfq_var_store(&__data, (page), count); \ | |
2440 | if (__data < (MIN)) \ | |
2441 | __data = (MIN); \ | |
2442 | else if (__data > (MAX)) \ | |
2443 | __data = (MAX); \ | |
2444 | if (__CONV) \ | |
2445 | *(__PTR) = msecs_to_jiffies(__data); \ | |
2446 | else \ | |
2447 | *(__PTR) = __data; \ | |
2448 | return ret; \ | |
2449 | } | |
2450 | STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); | |
2451 | STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); | |
22e2c507 JA |
2452 | STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); |
2453 | STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); | |
1da177e4 LT |
2454 | STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
2455 | STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); | |
22e2c507 JA |
2456 | STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); |
2457 | STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); | |
2458 | STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); | |
2459 | STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); | |
2460 | STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0); | |
1da177e4 LT |
2461 | #undef STORE_FUNCTION |
2462 | ||
2463 | static struct cfq_fs_entry cfq_quantum_entry = { | |
2464 | .attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR }, | |
2465 | .show = cfq_quantum_show, | |
2466 | .store = cfq_quantum_store, | |
2467 | }; | |
2468 | static struct cfq_fs_entry cfq_queued_entry = { | |
2469 | .attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR }, | |
2470 | .show = cfq_queued_show, | |
2471 | .store = cfq_queued_store, | |
2472 | }; | |
22e2c507 | 2473 | static struct cfq_fs_entry cfq_fifo_expire_sync_entry = { |
1da177e4 | 2474 | .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, |
22e2c507 JA |
2475 | .show = cfq_fifo_expire_sync_show, |
2476 | .store = cfq_fifo_expire_sync_store, | |
1da177e4 | 2477 | }; |
22e2c507 | 2478 | static struct cfq_fs_entry cfq_fifo_expire_async_entry = { |
1da177e4 | 2479 | .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, |
22e2c507 JA |
2480 | .show = cfq_fifo_expire_async_show, |
2481 | .store = cfq_fifo_expire_async_store, | |
1da177e4 LT |
2482 | }; |
2483 | static struct cfq_fs_entry cfq_back_max_entry = { | |
2484 | .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR }, | |
2485 | .show = cfq_back_max_show, | |
2486 | .store = cfq_back_max_store, | |
2487 | }; | |
2488 | static struct cfq_fs_entry cfq_back_penalty_entry = { | |
2489 | .attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR }, | |
2490 | .show = cfq_back_penalty_show, | |
2491 | .store = cfq_back_penalty_store, | |
2492 | }; | |
22e2c507 JA |
2493 | static struct cfq_fs_entry cfq_slice_sync_entry = { |
2494 | .attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR }, | |
2495 | .show = cfq_slice_sync_show, | |
2496 | .store = cfq_slice_sync_store, | |
1da177e4 | 2497 | }; |
22e2c507 JA |
2498 | static struct cfq_fs_entry cfq_slice_async_entry = { |
2499 | .attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR }, | |
2500 | .show = cfq_slice_async_show, | |
2501 | .store = cfq_slice_async_store, | |
2502 | }; | |
2503 | static struct cfq_fs_entry cfq_slice_async_rq_entry = { | |
2504 | .attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR }, | |
2505 | .show = cfq_slice_async_rq_show, | |
2506 | .store = cfq_slice_async_rq_store, | |
2507 | }; | |
2508 | static struct cfq_fs_entry cfq_slice_idle_entry = { | |
2509 | .attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR }, | |
2510 | .show = cfq_slice_idle_show, | |
2511 | .store = cfq_slice_idle_store, | |
2512 | }; | |
2513 | static struct cfq_fs_entry cfq_max_depth_entry = { | |
2514 | .attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR }, | |
2515 | .show = cfq_max_depth_show, | |
2516 | .store = cfq_max_depth_store, | |
1da177e4 | 2517 | }; |
3b18152c | 2518 | |
1da177e4 LT |
2519 | static struct attribute *default_attrs[] = { |
2520 | &cfq_quantum_entry.attr, | |
2521 | &cfq_queued_entry.attr, | |
22e2c507 JA |
2522 | &cfq_fifo_expire_sync_entry.attr, |
2523 | &cfq_fifo_expire_async_entry.attr, | |
1da177e4 LT |
2524 | &cfq_back_max_entry.attr, |
2525 | &cfq_back_penalty_entry.attr, | |
22e2c507 JA |
2526 | &cfq_slice_sync_entry.attr, |
2527 | &cfq_slice_async_entry.attr, | |
2528 | &cfq_slice_async_rq_entry.attr, | |
2529 | &cfq_slice_idle_entry.attr, | |
2530 | &cfq_max_depth_entry.attr, | |
1da177e4 LT |
2531 | NULL, |
2532 | }; | |
2533 | ||
2534 | #define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr) | |
2535 | ||
2536 | static ssize_t | |
2537 | cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page) | |
2538 | { | |
2539 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
2540 | struct cfq_fs_entry *entry = to_cfq(attr); | |
2541 | ||
2542 | if (!entry->show) | |
6c1852a0 | 2543 | return -EIO; |
1da177e4 LT |
2544 | |
2545 | return entry->show(e->elevator_data, page); | |
2546 | } | |
2547 | ||
2548 | static ssize_t | |
2549 | cfq_attr_store(struct kobject *kobj, struct attribute *attr, | |
2550 | const char *page, size_t length) | |
2551 | { | |
2552 | elevator_t *e = container_of(kobj, elevator_t, kobj); | |
2553 | struct cfq_fs_entry *entry = to_cfq(attr); | |
2554 | ||
2555 | if (!entry->store) | |
6c1852a0 | 2556 | return -EIO; |
1da177e4 LT |
2557 | |
2558 | return entry->store(e->elevator_data, page, length); | |
2559 | } | |
2560 | ||
2561 | static struct sysfs_ops cfq_sysfs_ops = { | |
2562 | .show = cfq_attr_show, | |
2563 | .store = cfq_attr_store, | |
2564 | }; | |
2565 | ||
2566 | static struct kobj_type cfq_ktype = { | |
2567 | .sysfs_ops = &cfq_sysfs_ops, | |
2568 | .default_attrs = default_attrs, | |
2569 | }; | |
2570 | ||
2571 | static struct elevator_type iosched_cfq = { | |
2572 | .ops = { | |
2573 | .elevator_merge_fn = cfq_merge, | |
2574 | .elevator_merged_fn = cfq_merged_request, | |
2575 | .elevator_merge_req_fn = cfq_merged_requests, | |
2576 | .elevator_next_req_fn = cfq_next_request, | |
2577 | .elevator_add_req_fn = cfq_insert_request, | |
2578 | .elevator_remove_req_fn = cfq_remove_request, | |
2579 | .elevator_requeue_req_fn = cfq_requeue_request, | |
2580 | .elevator_deactivate_req_fn = cfq_deactivate_request, | |
2581 | .elevator_queue_empty_fn = cfq_queue_empty, | |
2582 | .elevator_completed_req_fn = cfq_completed_request, | |
2583 | .elevator_former_req_fn = cfq_former_request, | |
2584 | .elevator_latter_req_fn = cfq_latter_request, | |
2585 | .elevator_set_req_fn = cfq_set_request, | |
2586 | .elevator_put_req_fn = cfq_put_request, | |
2587 | .elevator_may_queue_fn = cfq_may_queue, | |
2588 | .elevator_init_fn = cfq_init_queue, | |
2589 | .elevator_exit_fn = cfq_exit_queue, | |
2590 | }, | |
2591 | .elevator_ktype = &cfq_ktype, | |
2592 | .elevator_name = "cfq", | |
2593 | .elevator_owner = THIS_MODULE, | |
2594 | }; | |
2595 | ||
2596 | static int __init cfq_init(void) | |
2597 | { | |
2598 | int ret; | |
2599 | ||
22e2c507 JA |
2600 | /* |
2601 | * could be 0 on HZ < 1000 setups | |
2602 | */ | |
2603 | if (!cfq_slice_async) | |
2604 | cfq_slice_async = 1; | |
2605 | if (!cfq_slice_idle) | |
2606 | cfq_slice_idle = 1; | |
2607 | ||
1da177e4 LT |
2608 | if (cfq_slab_setup()) |
2609 | return -ENOMEM; | |
2610 | ||
2611 | ret = elv_register(&iosched_cfq); | |
22e2c507 JA |
2612 | if (ret) |
2613 | cfq_slab_kill(); | |
1da177e4 | 2614 | |
1da177e4 LT |
2615 | return ret; |
2616 | } | |
2617 | ||
2618 | static void __exit cfq_exit(void) | |
2619 | { | |
22e2c507 JA |
2620 | struct task_struct *g, *p; |
2621 | unsigned long flags; | |
2622 | ||
2623 | read_lock_irqsave(&tasklist_lock, flags); | |
2624 | ||
2625 | /* | |
2626 | * iterate each process in the system, removing our io_context | |
2627 | */ | |
2628 | do_each_thread(g, p) { | |
2629 | struct io_context *ioc = p->io_context; | |
2630 | ||
2631 | if (ioc && ioc->cic) { | |
2632 | ioc->cic->exit(ioc->cic); | |
2633 | cfq_free_io_context(ioc->cic); | |
2634 | ioc->cic = NULL; | |
2635 | } | |
2636 | } while_each_thread(g, p); | |
2637 | ||
2638 | read_unlock_irqrestore(&tasklist_lock, flags); | |
2639 | ||
1da177e4 LT |
2640 | cfq_slab_kill(); |
2641 | elv_unregister(&iosched_cfq); | |
2642 | } | |
2643 | ||
2644 | module_init(cfq_init); | |
2645 | module_exit(cfq_exit); | |
2646 | ||
2647 | MODULE_AUTHOR("Jens Axboe"); | |
2648 | MODULE_LICENSE("GPL"); | |
2649 | MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |