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Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Deadline i/o scheduler. |
3 | * | |
4 | * Copyright (C) 2002 Jens Axboe <axboe@suse.de> | |
5 | */ | |
6 | #include <linux/kernel.h> | |
7 | #include <linux/fs.h> | |
8 | #include <linux/blkdev.h> | |
9 | #include <linux/elevator.h> | |
10 | #include <linux/bio.h> | |
11 | #include <linux/config.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/compiler.h> | |
16 | #include <linux/hash.h> | |
17 | #include <linux/rbtree.h> | |
18 | ||
19 | /* | |
20 | * See Documentation/block/deadline-iosched.txt | |
21 | */ | |
64100099 AV |
22 | static const int read_expire = HZ / 2; /* max time before a read is submitted. */ |
23 | static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */ | |
24 | static const int writes_starved = 2; /* max times reads can starve a write */ | |
25 | static const int fifo_batch = 16; /* # of sequential requests treated as one | |
1da177e4 LT |
26 | by the above parameters. For throughput. */ |
27 | ||
28 | static const int deadline_hash_shift = 5; | |
29 | #define DL_HASH_BLOCK(sec) ((sec) >> 3) | |
30 | #define DL_HASH_FN(sec) (hash_long(DL_HASH_BLOCK((sec)), deadline_hash_shift)) | |
31 | #define DL_HASH_ENTRIES (1 << deadline_hash_shift) | |
32 | #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) | |
33 | #define list_entry_hash(ptr) list_entry((ptr), struct deadline_rq, hash) | |
34 | #define ON_HASH(drq) (drq)->on_hash | |
35 | ||
36 | struct deadline_data { | |
37 | /* | |
38 | * run time data | |
39 | */ | |
40 | ||
41 | /* | |
42 | * requests (deadline_rq s) are present on both sort_list and fifo_list | |
43 | */ | |
44 | struct rb_root sort_list[2]; | |
45 | struct list_head fifo_list[2]; | |
46 | ||
47 | /* | |
48 | * next in sort order. read, write or both are NULL | |
49 | */ | |
50 | struct deadline_rq *next_drq[2]; | |
1da177e4 LT |
51 | struct list_head *hash; /* request hash */ |
52 | unsigned int batching; /* number of sequential requests made */ | |
53 | sector_t last_sector; /* head position */ | |
54 | unsigned int starved; /* times reads have starved writes */ | |
55 | ||
56 | /* | |
57 | * settings that change how the i/o scheduler behaves | |
58 | */ | |
59 | int fifo_expire[2]; | |
60 | int fifo_batch; | |
61 | int writes_starved; | |
62 | int front_merges; | |
63 | ||
64 | mempool_t *drq_pool; | |
65 | }; | |
66 | ||
67 | /* | |
68 | * pre-request data. | |
69 | */ | |
70 | struct deadline_rq { | |
71 | /* | |
72 | * rbtree index, key is the starting offset | |
73 | */ | |
74 | struct rb_node rb_node; | |
75 | sector_t rb_key; | |
76 | ||
77 | struct request *request; | |
78 | ||
79 | /* | |
80 | * request hash, key is the ending offset (for back merge lookup) | |
81 | */ | |
82 | struct list_head hash; | |
83 | char on_hash; | |
84 | ||
85 | /* | |
86 | * expire fifo | |
87 | */ | |
88 | struct list_head fifo; | |
89 | unsigned long expires; | |
90 | }; | |
91 | ||
92 | static void deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq); | |
93 | ||
94 | static kmem_cache_t *drq_pool; | |
95 | ||
96 | #define RQ_DATA(rq) ((struct deadline_rq *) (rq)->elevator_private) | |
97 | ||
98 | /* | |
99 | * the back merge hash support functions | |
100 | */ | |
101 | static inline void __deadline_del_drq_hash(struct deadline_rq *drq) | |
102 | { | |
103 | drq->on_hash = 0; | |
104 | list_del_init(&drq->hash); | |
105 | } | |
106 | ||
107 | static inline void deadline_del_drq_hash(struct deadline_rq *drq) | |
108 | { | |
109 | if (ON_HASH(drq)) | |
110 | __deadline_del_drq_hash(drq); | |
111 | } | |
112 | ||
1da177e4 LT |
113 | static inline void |
114 | deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq) | |
115 | { | |
116 | struct request *rq = drq->request; | |
117 | ||
118 | BUG_ON(ON_HASH(drq)); | |
119 | ||
120 | drq->on_hash = 1; | |
121 | list_add(&drq->hash, &dd->hash[DL_HASH_FN(rq_hash_key(rq))]); | |
122 | } | |
123 | ||
124 | /* | |
125 | * move hot entry to front of chain | |
126 | */ | |
127 | static inline void | |
128 | deadline_hot_drq_hash(struct deadline_data *dd, struct deadline_rq *drq) | |
129 | { | |
130 | struct request *rq = drq->request; | |
131 | struct list_head *head = &dd->hash[DL_HASH_FN(rq_hash_key(rq))]; | |
132 | ||
133 | if (ON_HASH(drq) && drq->hash.prev != head) { | |
134 | list_del(&drq->hash); | |
135 | list_add(&drq->hash, head); | |
136 | } | |
137 | } | |
138 | ||
139 | static struct request * | |
140 | deadline_find_drq_hash(struct deadline_data *dd, sector_t offset) | |
141 | { | |
142 | struct list_head *hash_list = &dd->hash[DL_HASH_FN(offset)]; | |
143 | struct list_head *entry, *next = hash_list->next; | |
144 | ||
145 | while ((entry = next) != hash_list) { | |
146 | struct deadline_rq *drq = list_entry_hash(entry); | |
147 | struct request *__rq = drq->request; | |
148 | ||
149 | next = entry->next; | |
150 | ||
151 | BUG_ON(!ON_HASH(drq)); | |
152 | ||
153 | if (!rq_mergeable(__rq)) { | |
154 | __deadline_del_drq_hash(drq); | |
155 | continue; | |
156 | } | |
157 | ||
158 | if (rq_hash_key(__rq) == offset) | |
159 | return __rq; | |
160 | } | |
161 | ||
162 | return NULL; | |
163 | } | |
164 | ||
165 | /* | |
166 | * rb tree support functions | |
167 | */ | |
1da177e4 | 168 | #define RB_EMPTY(root) ((root)->rb_node == NULL) |
3db3a445 DW |
169 | #define ON_RB(node) (rb_parent(node) != node) |
170 | #define RB_CLEAR(node) (rb_set_parent(node, node)) | |
1da177e4 LT |
171 | #define rb_entry_drq(node) rb_entry((node), struct deadline_rq, rb_node) |
172 | #define DRQ_RB_ROOT(dd, drq) (&(dd)->sort_list[rq_data_dir((drq)->request)]) | |
173 | #define rq_rb_key(rq) (rq)->sector | |
174 | ||
175 | static struct deadline_rq * | |
176 | __deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) | |
177 | { | |
178 | struct rb_node **p = &DRQ_RB_ROOT(dd, drq)->rb_node; | |
179 | struct rb_node *parent = NULL; | |
180 | struct deadline_rq *__drq; | |
181 | ||
182 | while (*p) { | |
183 | parent = *p; | |
184 | __drq = rb_entry_drq(parent); | |
185 | ||
186 | if (drq->rb_key < __drq->rb_key) | |
187 | p = &(*p)->rb_left; | |
188 | else if (drq->rb_key > __drq->rb_key) | |
189 | p = &(*p)->rb_right; | |
190 | else | |
191 | return __drq; | |
192 | } | |
193 | ||
194 | rb_link_node(&drq->rb_node, parent, p); | |
195 | return NULL; | |
196 | } | |
197 | ||
198 | static void | |
199 | deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) | |
200 | { | |
201 | struct deadline_rq *__alias; | |
202 | ||
203 | drq->rb_key = rq_rb_key(drq->request); | |
204 | ||
205 | retry: | |
206 | __alias = __deadline_add_drq_rb(dd, drq); | |
207 | if (!__alias) { | |
208 | rb_insert_color(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); | |
209 | return; | |
210 | } | |
211 | ||
212 | deadline_move_request(dd, __alias); | |
213 | goto retry; | |
214 | } | |
215 | ||
216 | static inline void | |
217 | deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) | |
218 | { | |
219 | const int data_dir = rq_data_dir(drq->request); | |
220 | ||
221 | if (dd->next_drq[data_dir] == drq) { | |
222 | struct rb_node *rbnext = rb_next(&drq->rb_node); | |
223 | ||
224 | dd->next_drq[data_dir] = NULL; | |
225 | if (rbnext) | |
226 | dd->next_drq[data_dir] = rb_entry_drq(rbnext); | |
227 | } | |
228 | ||
b4878f24 JA |
229 | BUG_ON(!ON_RB(&drq->rb_node)); |
230 | rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); | |
231 | RB_CLEAR(&drq->rb_node); | |
1da177e4 LT |
232 | } |
233 | ||
234 | static struct request * | |
235 | deadline_find_drq_rb(struct deadline_data *dd, sector_t sector, int data_dir) | |
236 | { | |
237 | struct rb_node *n = dd->sort_list[data_dir].rb_node; | |
238 | struct deadline_rq *drq; | |
239 | ||
240 | while (n) { | |
241 | drq = rb_entry_drq(n); | |
242 | ||
243 | if (sector < drq->rb_key) | |
244 | n = n->rb_left; | |
245 | else if (sector > drq->rb_key) | |
246 | n = n->rb_right; | |
247 | else | |
248 | return drq->request; | |
249 | } | |
250 | ||
251 | return NULL; | |
252 | } | |
253 | ||
254 | /* | |
255 | * deadline_find_first_drq finds the first (lowest sector numbered) request | |
256 | * for the specified data_dir. Used to sweep back to the start of the disk | |
257 | * (1-way elevator) after we process the last (highest sector) request. | |
258 | */ | |
259 | static struct deadline_rq * | |
260 | deadline_find_first_drq(struct deadline_data *dd, int data_dir) | |
261 | { | |
262 | struct rb_node *n = dd->sort_list[data_dir].rb_node; | |
263 | ||
264 | for (;;) { | |
265 | if (n->rb_left == NULL) | |
266 | return rb_entry_drq(n); | |
267 | ||
268 | n = n->rb_left; | |
269 | } | |
270 | } | |
271 | ||
272 | /* | |
273 | * add drq to rbtree and fifo | |
274 | */ | |
b4878f24 | 275 | static void |
1da177e4 LT |
276 | deadline_add_request(struct request_queue *q, struct request *rq) |
277 | { | |
278 | struct deadline_data *dd = q->elevator->elevator_data; | |
279 | struct deadline_rq *drq = RQ_DATA(rq); | |
280 | ||
281 | const int data_dir = rq_data_dir(drq->request); | |
282 | ||
283 | deadline_add_drq_rb(dd, drq); | |
284 | /* | |
285 | * set expire time (only used for reads) and add to fifo list | |
286 | */ | |
287 | drq->expires = jiffies + dd->fifo_expire[data_dir]; | |
288 | list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]); | |
289 | ||
98b11471 | 290 | if (rq_mergeable(rq)) |
1da177e4 | 291 | deadline_add_drq_hash(dd, drq); |
1da177e4 LT |
292 | } |
293 | ||
294 | /* | |
295 | * remove rq from rbtree, fifo, and hash | |
296 | */ | |
297 | static void deadline_remove_request(request_queue_t *q, struct request *rq) | |
298 | { | |
299 | struct deadline_rq *drq = RQ_DATA(rq); | |
b4878f24 | 300 | struct deadline_data *dd = q->elevator->elevator_data; |
1da177e4 | 301 | |
b4878f24 | 302 | list_del_init(&drq->fifo); |
b4878f24 | 303 | deadline_del_drq_rb(dd, drq); |
98b11471 | 304 | deadline_del_drq_hash(drq); |
1da177e4 LT |
305 | } |
306 | ||
307 | static int | |
308 | deadline_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
309 | { | |
310 | struct deadline_data *dd = q->elevator->elevator_data; | |
311 | struct request *__rq; | |
312 | int ret; | |
313 | ||
1da177e4 LT |
314 | /* |
315 | * see if the merge hash can satisfy a back merge | |
316 | */ | |
317 | __rq = deadline_find_drq_hash(dd, bio->bi_sector); | |
318 | if (__rq) { | |
319 | BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector); | |
320 | ||
321 | if (elv_rq_merge_ok(__rq, bio)) { | |
322 | ret = ELEVATOR_BACK_MERGE; | |
323 | goto out; | |
324 | } | |
325 | } | |
326 | ||
327 | /* | |
328 | * check for front merge | |
329 | */ | |
330 | if (dd->front_merges) { | |
331 | sector_t rb_key = bio->bi_sector + bio_sectors(bio); | |
332 | ||
333 | __rq = deadline_find_drq_rb(dd, rb_key, bio_data_dir(bio)); | |
334 | if (__rq) { | |
335 | BUG_ON(rb_key != rq_rb_key(__rq)); | |
336 | ||
337 | if (elv_rq_merge_ok(__rq, bio)) { | |
338 | ret = ELEVATOR_FRONT_MERGE; | |
339 | goto out; | |
340 | } | |
341 | } | |
342 | } | |
343 | ||
344 | return ELEVATOR_NO_MERGE; | |
345 | out: | |
1da177e4 LT |
346 | if (ret) |
347 | deadline_hot_drq_hash(dd, RQ_DATA(__rq)); | |
348 | *req = __rq; | |
349 | return ret; | |
350 | } | |
351 | ||
352 | static void deadline_merged_request(request_queue_t *q, struct request *req) | |
353 | { | |
354 | struct deadline_data *dd = q->elevator->elevator_data; | |
355 | struct deadline_rq *drq = RQ_DATA(req); | |
356 | ||
357 | /* | |
358 | * hash always needs to be repositioned, key is end sector | |
359 | */ | |
360 | deadline_del_drq_hash(drq); | |
361 | deadline_add_drq_hash(dd, drq); | |
362 | ||
363 | /* | |
364 | * if the merge was a front merge, we need to reposition request | |
365 | */ | |
366 | if (rq_rb_key(req) != drq->rb_key) { | |
367 | deadline_del_drq_rb(dd, drq); | |
368 | deadline_add_drq_rb(dd, drq); | |
369 | } | |
1da177e4 LT |
370 | } |
371 | ||
372 | static void | |
373 | deadline_merged_requests(request_queue_t *q, struct request *req, | |
374 | struct request *next) | |
375 | { | |
376 | struct deadline_data *dd = q->elevator->elevator_data; | |
377 | struct deadline_rq *drq = RQ_DATA(req); | |
378 | struct deadline_rq *dnext = RQ_DATA(next); | |
379 | ||
380 | BUG_ON(!drq); | |
381 | BUG_ON(!dnext); | |
382 | ||
383 | /* | |
384 | * reposition drq (this is the merged request) in hash, and in rbtree | |
385 | * in case of a front merge | |
386 | */ | |
387 | deadline_del_drq_hash(drq); | |
388 | deadline_add_drq_hash(dd, drq); | |
389 | ||
390 | if (rq_rb_key(req) != drq->rb_key) { | |
391 | deadline_del_drq_rb(dd, drq); | |
392 | deadline_add_drq_rb(dd, drq); | |
393 | } | |
394 | ||
395 | /* | |
396 | * if dnext expires before drq, assign its expire time to drq | |
397 | * and move into dnext position (dnext will be deleted) in fifo | |
398 | */ | |
399 | if (!list_empty(&drq->fifo) && !list_empty(&dnext->fifo)) { | |
400 | if (time_before(dnext->expires, drq->expires)) { | |
401 | list_move(&drq->fifo, &dnext->fifo); | |
402 | drq->expires = dnext->expires; | |
403 | } | |
404 | } | |
405 | ||
406 | /* | |
407 | * kill knowledge of next, this one is a goner | |
408 | */ | |
409 | deadline_remove_request(q, next); | |
410 | } | |
411 | ||
412 | /* | |
413 | * move request from sort list to dispatch queue. | |
414 | */ | |
415 | static inline void | |
416 | deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq) | |
417 | { | |
418 | request_queue_t *q = drq->request->q; | |
419 | ||
420 | deadline_remove_request(q, drq->request); | |
b4878f24 | 421 | elv_dispatch_add_tail(q, drq->request); |
1da177e4 LT |
422 | } |
423 | ||
424 | /* | |
425 | * move an entry to dispatch queue | |
426 | */ | |
427 | static void | |
428 | deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq) | |
429 | { | |
430 | const int data_dir = rq_data_dir(drq->request); | |
431 | struct rb_node *rbnext = rb_next(&drq->rb_node); | |
432 | ||
433 | dd->next_drq[READ] = NULL; | |
434 | dd->next_drq[WRITE] = NULL; | |
435 | ||
436 | if (rbnext) | |
437 | dd->next_drq[data_dir] = rb_entry_drq(rbnext); | |
438 | ||
439 | dd->last_sector = drq->request->sector + drq->request->nr_sectors; | |
440 | ||
441 | /* | |
442 | * take it off the sort and fifo list, move | |
443 | * to dispatch queue | |
444 | */ | |
445 | deadline_move_to_dispatch(dd, drq); | |
446 | } | |
447 | ||
448 | #define list_entry_fifo(ptr) list_entry((ptr), struct deadline_rq, fifo) | |
449 | ||
450 | /* | |
451 | * deadline_check_fifo returns 0 if there are no expired reads on the fifo, | |
452 | * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir]) | |
453 | */ | |
454 | static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) | |
455 | { | |
456 | struct deadline_rq *drq = list_entry_fifo(dd->fifo_list[ddir].next); | |
457 | ||
458 | /* | |
459 | * drq is expired! | |
460 | */ | |
461 | if (time_after(jiffies, drq->expires)) | |
462 | return 1; | |
463 | ||
464 | return 0; | |
465 | } | |
466 | ||
467 | /* | |
468 | * deadline_dispatch_requests selects the best request according to | |
469 | * read/write expire, fifo_batch, etc | |
470 | */ | |
b4878f24 | 471 | static int deadline_dispatch_requests(request_queue_t *q, int force) |
1da177e4 | 472 | { |
b4878f24 | 473 | struct deadline_data *dd = q->elevator->elevator_data; |
1da177e4 LT |
474 | const int reads = !list_empty(&dd->fifo_list[READ]); |
475 | const int writes = !list_empty(&dd->fifo_list[WRITE]); | |
476 | struct deadline_rq *drq; | |
4b0dc07e | 477 | int data_dir; |
1da177e4 LT |
478 | |
479 | /* | |
480 | * batches are currently reads XOR writes | |
481 | */ | |
9d5c1e1b AM |
482 | if (dd->next_drq[WRITE]) |
483 | drq = dd->next_drq[WRITE]; | |
484 | else | |
485 | drq = dd->next_drq[READ]; | |
1da177e4 LT |
486 | |
487 | if (drq) { | |
488 | /* we have a "next request" */ | |
489 | ||
490 | if (dd->last_sector != drq->request->sector) | |
491 | /* end the batch on a non sequential request */ | |
492 | dd->batching += dd->fifo_batch; | |
493 | ||
494 | if (dd->batching < dd->fifo_batch) | |
495 | /* we are still entitled to batch */ | |
496 | goto dispatch_request; | |
497 | } | |
498 | ||
499 | /* | |
500 | * at this point we are not running a batch. select the appropriate | |
501 | * data direction (read / write) | |
502 | */ | |
503 | ||
504 | if (reads) { | |
505 | BUG_ON(RB_EMPTY(&dd->sort_list[READ])); | |
506 | ||
507 | if (writes && (dd->starved++ >= dd->writes_starved)) | |
508 | goto dispatch_writes; | |
509 | ||
510 | data_dir = READ; | |
1da177e4 LT |
511 | |
512 | goto dispatch_find_request; | |
513 | } | |
514 | ||
515 | /* | |
516 | * there are either no reads or writes have been starved | |
517 | */ | |
518 | ||
519 | if (writes) { | |
520 | dispatch_writes: | |
521 | BUG_ON(RB_EMPTY(&dd->sort_list[WRITE])); | |
522 | ||
523 | dd->starved = 0; | |
524 | ||
525 | data_dir = WRITE; | |
1da177e4 LT |
526 | |
527 | goto dispatch_find_request; | |
528 | } | |
529 | ||
530 | return 0; | |
531 | ||
532 | dispatch_find_request: | |
533 | /* | |
534 | * we are not running a batch, find best request for selected data_dir | |
535 | */ | |
536 | if (deadline_check_fifo(dd, data_dir)) { | |
537 | /* An expired request exists - satisfy it */ | |
538 | dd->batching = 0; | |
539 | drq = list_entry_fifo(dd->fifo_list[data_dir].next); | |
540 | ||
541 | } else if (dd->next_drq[data_dir]) { | |
542 | /* | |
543 | * The last req was the same dir and we have a next request in | |
544 | * sort order. No expired requests so continue on from here. | |
545 | */ | |
546 | drq = dd->next_drq[data_dir]; | |
547 | } else { | |
548 | /* | |
549 | * The last req was the other direction or we have run out of | |
550 | * higher-sectored requests. Go back to the lowest sectored | |
551 | * request (1 way elevator) and start a new batch. | |
552 | */ | |
553 | dd->batching = 0; | |
554 | drq = deadline_find_first_drq(dd, data_dir); | |
555 | } | |
556 | ||
557 | dispatch_request: | |
558 | /* | |
559 | * drq is the selected appropriate request. | |
560 | */ | |
561 | dd->batching++; | |
562 | deadline_move_request(dd, drq); | |
563 | ||
564 | return 1; | |
565 | } | |
566 | ||
1da177e4 LT |
567 | static int deadline_queue_empty(request_queue_t *q) |
568 | { | |
569 | struct deadline_data *dd = q->elevator->elevator_data; | |
570 | ||
b4878f24 JA |
571 | return list_empty(&dd->fifo_list[WRITE]) |
572 | && list_empty(&dd->fifo_list[READ]); | |
1da177e4 LT |
573 | } |
574 | ||
575 | static struct request * | |
576 | deadline_former_request(request_queue_t *q, struct request *rq) | |
577 | { | |
578 | struct deadline_rq *drq = RQ_DATA(rq); | |
579 | struct rb_node *rbprev = rb_prev(&drq->rb_node); | |
580 | ||
581 | if (rbprev) | |
582 | return rb_entry_drq(rbprev)->request; | |
583 | ||
584 | return NULL; | |
585 | } | |
586 | ||
587 | static struct request * | |
588 | deadline_latter_request(request_queue_t *q, struct request *rq) | |
589 | { | |
590 | struct deadline_rq *drq = RQ_DATA(rq); | |
591 | struct rb_node *rbnext = rb_next(&drq->rb_node); | |
592 | ||
593 | if (rbnext) | |
594 | return rb_entry_drq(rbnext)->request; | |
595 | ||
596 | return NULL; | |
597 | } | |
598 | ||
599 | static void deadline_exit_queue(elevator_t *e) | |
600 | { | |
601 | struct deadline_data *dd = e->elevator_data; | |
602 | ||
603 | BUG_ON(!list_empty(&dd->fifo_list[READ])); | |
604 | BUG_ON(!list_empty(&dd->fifo_list[WRITE])); | |
605 | ||
606 | mempool_destroy(dd->drq_pool); | |
607 | kfree(dd->hash); | |
608 | kfree(dd); | |
609 | } | |
610 | ||
611 | /* | |
612 | * initialize elevator private data (deadline_data), and alloc a drq for | |
613 | * each request on the free lists | |
614 | */ | |
bc1c1169 | 615 | static void *deadline_init_queue(request_queue_t *q, elevator_t *e) |
1da177e4 LT |
616 | { |
617 | struct deadline_data *dd; | |
618 | int i; | |
619 | ||
620 | if (!drq_pool) | |
bc1c1169 | 621 | return NULL; |
1da177e4 | 622 | |
1946089a | 623 | dd = kmalloc_node(sizeof(*dd), GFP_KERNEL, q->node); |
1da177e4 | 624 | if (!dd) |
bc1c1169 | 625 | return NULL; |
1da177e4 LT |
626 | memset(dd, 0, sizeof(*dd)); |
627 | ||
1946089a CL |
628 | dd->hash = kmalloc_node(sizeof(struct list_head)*DL_HASH_ENTRIES, |
629 | GFP_KERNEL, q->node); | |
1da177e4 LT |
630 | if (!dd->hash) { |
631 | kfree(dd); | |
bc1c1169 | 632 | return NULL; |
1da177e4 LT |
633 | } |
634 | ||
1946089a CL |
635 | dd->drq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, |
636 | mempool_free_slab, drq_pool, q->node); | |
1da177e4 LT |
637 | if (!dd->drq_pool) { |
638 | kfree(dd->hash); | |
639 | kfree(dd); | |
bc1c1169 | 640 | return NULL; |
1da177e4 LT |
641 | } |
642 | ||
643 | for (i = 0; i < DL_HASH_ENTRIES; i++) | |
644 | INIT_LIST_HEAD(&dd->hash[i]); | |
645 | ||
646 | INIT_LIST_HEAD(&dd->fifo_list[READ]); | |
647 | INIT_LIST_HEAD(&dd->fifo_list[WRITE]); | |
648 | dd->sort_list[READ] = RB_ROOT; | |
649 | dd->sort_list[WRITE] = RB_ROOT; | |
1da177e4 LT |
650 | dd->fifo_expire[READ] = read_expire; |
651 | dd->fifo_expire[WRITE] = write_expire; | |
652 | dd->writes_starved = writes_starved; | |
653 | dd->front_merges = 1; | |
654 | dd->fifo_batch = fifo_batch; | |
bc1c1169 | 655 | return dd; |
1da177e4 LT |
656 | } |
657 | ||
658 | static void deadline_put_request(request_queue_t *q, struct request *rq) | |
659 | { | |
660 | struct deadline_data *dd = q->elevator->elevator_data; | |
661 | struct deadline_rq *drq = RQ_DATA(rq); | |
662 | ||
b4878f24 JA |
663 | mempool_free(drq, dd->drq_pool); |
664 | rq->elevator_private = NULL; | |
1da177e4 LT |
665 | } |
666 | ||
667 | static int | |
22e2c507 | 668 | deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio, |
8267e268 | 669 | gfp_t gfp_mask) |
1da177e4 LT |
670 | { |
671 | struct deadline_data *dd = q->elevator->elevator_data; | |
672 | struct deadline_rq *drq; | |
673 | ||
674 | drq = mempool_alloc(dd->drq_pool, gfp_mask); | |
675 | if (drq) { | |
676 | memset(drq, 0, sizeof(*drq)); | |
677 | RB_CLEAR(&drq->rb_node); | |
678 | drq->request = rq; | |
679 | ||
680 | INIT_LIST_HEAD(&drq->hash); | |
681 | drq->on_hash = 0; | |
682 | ||
683 | INIT_LIST_HEAD(&drq->fifo); | |
684 | ||
685 | rq->elevator_private = drq; | |
686 | return 0; | |
687 | } | |
688 | ||
689 | return 1; | |
690 | } | |
691 | ||
692 | /* | |
693 | * sysfs parts below | |
694 | */ | |
1da177e4 LT |
695 | |
696 | static ssize_t | |
697 | deadline_var_show(int var, char *page) | |
698 | { | |
699 | return sprintf(page, "%d\n", var); | |
700 | } | |
701 | ||
702 | static ssize_t | |
703 | deadline_var_store(int *var, const char *page, size_t count) | |
704 | { | |
705 | char *p = (char *) page; | |
706 | ||
707 | *var = simple_strtol(p, &p, 10); | |
708 | return count; | |
709 | } | |
710 | ||
711 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ | |
3d1ab40f | 712 | static ssize_t __FUNC(elevator_t *e, char *page) \ |
1da177e4 | 713 | { \ |
3d1ab40f AV |
714 | struct deadline_data *dd = e->elevator_data; \ |
715 | int __data = __VAR; \ | |
1da177e4 LT |
716 | if (__CONV) \ |
717 | __data = jiffies_to_msecs(__data); \ | |
718 | return deadline_var_show(__data, (page)); \ | |
719 | } | |
e572ec7e AV |
720 | SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[READ], 1); |
721 | SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[WRITE], 1); | |
722 | SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0); | |
723 | SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0); | |
724 | SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0); | |
1da177e4 LT |
725 | #undef SHOW_FUNCTION |
726 | ||
727 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
3d1ab40f | 728 | static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ |
1da177e4 | 729 | { \ |
3d1ab40f | 730 | struct deadline_data *dd = e->elevator_data; \ |
1da177e4 LT |
731 | int __data; \ |
732 | int ret = deadline_var_store(&__data, (page), count); \ | |
733 | if (__data < (MIN)) \ | |
734 | __data = (MIN); \ | |
735 | else if (__data > (MAX)) \ | |
736 | __data = (MAX); \ | |
737 | if (__CONV) \ | |
738 | *(__PTR) = msecs_to_jiffies(__data); \ | |
739 | else \ | |
740 | *(__PTR) = __data; \ | |
741 | return ret; \ | |
742 | } | |
e572ec7e AV |
743 | STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1); |
744 | STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1); | |
745 | STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0); | |
746 | STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0); | |
747 | STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0); | |
1da177e4 LT |
748 | #undef STORE_FUNCTION |
749 | ||
e572ec7e AV |
750 | #define DD_ATTR(name) \ |
751 | __ATTR(name, S_IRUGO|S_IWUSR, deadline_##name##_show, \ | |
752 | deadline_##name##_store) | |
753 | ||
754 | static struct elv_fs_entry deadline_attrs[] = { | |
755 | DD_ATTR(read_expire), | |
756 | DD_ATTR(write_expire), | |
757 | DD_ATTR(writes_starved), | |
758 | DD_ATTR(front_merges), | |
759 | DD_ATTR(fifo_batch), | |
760 | __ATTR_NULL | |
1da177e4 LT |
761 | }; |
762 | ||
1da177e4 LT |
763 | static struct elevator_type iosched_deadline = { |
764 | .ops = { | |
765 | .elevator_merge_fn = deadline_merge, | |
766 | .elevator_merged_fn = deadline_merged_request, | |
767 | .elevator_merge_req_fn = deadline_merged_requests, | |
b4878f24 JA |
768 | .elevator_dispatch_fn = deadline_dispatch_requests, |
769 | .elevator_add_req_fn = deadline_add_request, | |
1da177e4 LT |
770 | .elevator_queue_empty_fn = deadline_queue_empty, |
771 | .elevator_former_req_fn = deadline_former_request, | |
772 | .elevator_latter_req_fn = deadline_latter_request, | |
773 | .elevator_set_req_fn = deadline_set_request, | |
774 | .elevator_put_req_fn = deadline_put_request, | |
775 | .elevator_init_fn = deadline_init_queue, | |
776 | .elevator_exit_fn = deadline_exit_queue, | |
777 | }, | |
778 | ||
3d1ab40f | 779 | .elevator_attrs = deadline_attrs, |
1da177e4 LT |
780 | .elevator_name = "deadline", |
781 | .elevator_owner = THIS_MODULE, | |
782 | }; | |
783 | ||
784 | static int __init deadline_init(void) | |
785 | { | |
786 | int ret; | |
787 | ||
788 | drq_pool = kmem_cache_create("deadline_drq", sizeof(struct deadline_rq), | |
789 | 0, 0, NULL, NULL); | |
790 | ||
791 | if (!drq_pool) | |
792 | return -ENOMEM; | |
793 | ||
794 | ret = elv_register(&iosched_deadline); | |
795 | if (ret) | |
796 | kmem_cache_destroy(drq_pool); | |
797 | ||
798 | return ret; | |
799 | } | |
800 | ||
801 | static void __exit deadline_exit(void) | |
802 | { | |
803 | kmem_cache_destroy(drq_pool); | |
804 | elv_unregister(&iosched_deadline); | |
805 | } | |
806 | ||
807 | module_init(deadline_init); | |
808 | module_exit(deadline_exit); | |
809 | ||
810 | MODULE_AUTHOR("Jens Axboe"); | |
811 | MODULE_LICENSE("GPL"); | |
812 | MODULE_DESCRIPTION("deadline IO scheduler"); |