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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> | |
1da177e4 LT |
11 | #include <linux/module.h> |
12 | #include <linux/slab.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/compiler.h> | |
1da177e4 LT |
15 | #include <linux/rbtree.h> |
16 | ||
17 | /* | |
18 | * See Documentation/block/deadline-iosched.txt | |
19 | */ | |
64100099 AV |
20 | static const int read_expire = HZ / 2; /* max time before a read is submitted. */ |
21 | static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */ | |
22 | static const int writes_starved = 2; /* max times reads can starve a write */ | |
23 | static const int fifo_batch = 16; /* # of sequential requests treated as one | |
1da177e4 LT |
24 | by the above parameters. For throughput. */ |
25 | ||
1da177e4 LT |
26 | struct deadline_data { |
27 | /* | |
28 | * run time data | |
29 | */ | |
30 | ||
31 | /* | |
32 | * requests (deadline_rq s) are present on both sort_list and fifo_list | |
33 | */ | |
34 | struct rb_root sort_list[2]; | |
35 | struct list_head fifo_list[2]; | |
36 | ||
37 | /* | |
38 | * next in sort order. read, write or both are NULL | |
39 | */ | |
40 | struct deadline_rq *next_drq[2]; | |
1da177e4 LT |
41 | unsigned int batching; /* number of sequential requests made */ |
42 | sector_t last_sector; /* head position */ | |
43 | unsigned int starved; /* times reads have starved writes */ | |
44 | ||
45 | /* | |
46 | * settings that change how the i/o scheduler behaves | |
47 | */ | |
48 | int fifo_expire[2]; | |
49 | int fifo_batch; | |
50 | int writes_starved; | |
51 | int front_merges; | |
52 | ||
53 | mempool_t *drq_pool; | |
54 | }; | |
55 | ||
56 | /* | |
57 | * pre-request data. | |
58 | */ | |
59 | struct deadline_rq { | |
60 | /* | |
61 | * rbtree index, key is the starting offset | |
62 | */ | |
63 | struct rb_node rb_node; | |
64 | sector_t rb_key; | |
65 | ||
66 | struct request *request; | |
67 | ||
1da177e4 LT |
68 | /* |
69 | * expire fifo | |
70 | */ | |
71 | struct list_head fifo; | |
72 | unsigned long expires; | |
73 | }; | |
74 | ||
75 | static void deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq); | |
76 | ||
77 | static kmem_cache_t *drq_pool; | |
78 | ||
79 | #define RQ_DATA(rq) ((struct deadline_rq *) (rq)->elevator_private) | |
80 | ||
1da177e4 LT |
81 | /* |
82 | * rb tree support functions | |
83 | */ | |
1da177e4 LT |
84 | #define rb_entry_drq(node) rb_entry((node), struct deadline_rq, rb_node) |
85 | #define DRQ_RB_ROOT(dd, drq) (&(dd)->sort_list[rq_data_dir((drq)->request)]) | |
86 | #define rq_rb_key(rq) (rq)->sector | |
87 | ||
88 | static struct deadline_rq * | |
89 | __deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) | |
90 | { | |
91 | struct rb_node **p = &DRQ_RB_ROOT(dd, drq)->rb_node; | |
92 | struct rb_node *parent = NULL; | |
93 | struct deadline_rq *__drq; | |
94 | ||
95 | while (*p) { | |
96 | parent = *p; | |
97 | __drq = rb_entry_drq(parent); | |
98 | ||
99 | if (drq->rb_key < __drq->rb_key) | |
100 | p = &(*p)->rb_left; | |
101 | else if (drq->rb_key > __drq->rb_key) | |
102 | p = &(*p)->rb_right; | |
103 | else | |
104 | return __drq; | |
105 | } | |
106 | ||
107 | rb_link_node(&drq->rb_node, parent, p); | |
108 | return NULL; | |
109 | } | |
110 | ||
111 | static void | |
112 | deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) | |
113 | { | |
114 | struct deadline_rq *__alias; | |
115 | ||
116 | drq->rb_key = rq_rb_key(drq->request); | |
117 | ||
118 | retry: | |
119 | __alias = __deadline_add_drq_rb(dd, drq); | |
120 | if (!__alias) { | |
121 | rb_insert_color(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); | |
122 | return; | |
123 | } | |
124 | ||
125 | deadline_move_request(dd, __alias); | |
126 | goto retry; | |
127 | } | |
128 | ||
129 | static inline void | |
130 | deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) | |
131 | { | |
132 | const int data_dir = rq_data_dir(drq->request); | |
133 | ||
134 | if (dd->next_drq[data_dir] == drq) { | |
135 | struct rb_node *rbnext = rb_next(&drq->rb_node); | |
136 | ||
137 | dd->next_drq[data_dir] = NULL; | |
138 | if (rbnext) | |
139 | dd->next_drq[data_dir] = rb_entry_drq(rbnext); | |
140 | } | |
141 | ||
dd67d051 | 142 | BUG_ON(!RB_EMPTY_NODE(&drq->rb_node)); |
b4878f24 | 143 | rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); |
dd67d051 | 144 | RB_CLEAR_NODE(&drq->rb_node); |
1da177e4 LT |
145 | } |
146 | ||
147 | static struct request * | |
148 | deadline_find_drq_rb(struct deadline_data *dd, sector_t sector, int data_dir) | |
149 | { | |
150 | struct rb_node *n = dd->sort_list[data_dir].rb_node; | |
151 | struct deadline_rq *drq; | |
152 | ||
153 | while (n) { | |
154 | drq = rb_entry_drq(n); | |
155 | ||
156 | if (sector < drq->rb_key) | |
157 | n = n->rb_left; | |
158 | else if (sector > drq->rb_key) | |
159 | n = n->rb_right; | |
160 | else | |
161 | return drq->request; | |
162 | } | |
163 | ||
164 | return NULL; | |
165 | } | |
166 | ||
167 | /* | |
168 | * deadline_find_first_drq finds the first (lowest sector numbered) request | |
169 | * for the specified data_dir. Used to sweep back to the start of the disk | |
170 | * (1-way elevator) after we process the last (highest sector) request. | |
171 | */ | |
172 | static struct deadline_rq * | |
173 | deadline_find_first_drq(struct deadline_data *dd, int data_dir) | |
174 | { | |
175 | struct rb_node *n = dd->sort_list[data_dir].rb_node; | |
176 | ||
177 | for (;;) { | |
178 | if (n->rb_left == NULL) | |
179 | return rb_entry_drq(n); | |
180 | ||
181 | n = n->rb_left; | |
182 | } | |
183 | } | |
184 | ||
185 | /* | |
186 | * add drq to rbtree and fifo | |
187 | */ | |
b4878f24 | 188 | static void |
1da177e4 LT |
189 | deadline_add_request(struct request_queue *q, struct request *rq) |
190 | { | |
191 | struct deadline_data *dd = q->elevator->elevator_data; | |
192 | struct deadline_rq *drq = RQ_DATA(rq); | |
1da177e4 LT |
193 | const int data_dir = rq_data_dir(drq->request); |
194 | ||
195 | deadline_add_drq_rb(dd, drq); | |
9817064b | 196 | |
1da177e4 LT |
197 | /* |
198 | * set expire time (only used for reads) and add to fifo list | |
199 | */ | |
200 | drq->expires = jiffies + dd->fifo_expire[data_dir]; | |
201 | list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]); | |
1da177e4 LT |
202 | } |
203 | ||
204 | /* | |
9817064b | 205 | * remove rq from rbtree and fifo. |
1da177e4 LT |
206 | */ |
207 | static void deadline_remove_request(request_queue_t *q, struct request *rq) | |
208 | { | |
209 | struct deadline_rq *drq = RQ_DATA(rq); | |
b4878f24 | 210 | struct deadline_data *dd = q->elevator->elevator_data; |
1da177e4 | 211 | |
b4878f24 | 212 | list_del_init(&drq->fifo); |
b4878f24 | 213 | deadline_del_drq_rb(dd, drq); |
1da177e4 LT |
214 | } |
215 | ||
216 | static int | |
217 | deadline_merge(request_queue_t *q, struct request **req, struct bio *bio) | |
218 | { | |
219 | struct deadline_data *dd = q->elevator->elevator_data; | |
220 | struct request *__rq; | |
221 | int ret; | |
222 | ||
1da177e4 LT |
223 | /* |
224 | * check for front merge | |
225 | */ | |
226 | if (dd->front_merges) { | |
227 | sector_t rb_key = bio->bi_sector + bio_sectors(bio); | |
228 | ||
229 | __rq = deadline_find_drq_rb(dd, rb_key, bio_data_dir(bio)); | |
230 | if (__rq) { | |
231 | BUG_ON(rb_key != rq_rb_key(__rq)); | |
232 | ||
233 | if (elv_rq_merge_ok(__rq, bio)) { | |
234 | ret = ELEVATOR_FRONT_MERGE; | |
235 | goto out; | |
236 | } | |
237 | } | |
238 | } | |
239 | ||
240 | return ELEVATOR_NO_MERGE; | |
241 | out: | |
1da177e4 LT |
242 | *req = __rq; |
243 | return ret; | |
244 | } | |
245 | ||
246 | static void deadline_merged_request(request_queue_t *q, struct request *req) | |
247 | { | |
248 | struct deadline_data *dd = q->elevator->elevator_data; | |
249 | struct deadline_rq *drq = RQ_DATA(req); | |
250 | ||
1da177e4 LT |
251 | /* |
252 | * if the merge was a front merge, we need to reposition request | |
253 | */ | |
254 | if (rq_rb_key(req) != drq->rb_key) { | |
255 | deadline_del_drq_rb(dd, drq); | |
256 | deadline_add_drq_rb(dd, drq); | |
257 | } | |
1da177e4 LT |
258 | } |
259 | ||
260 | static void | |
261 | deadline_merged_requests(request_queue_t *q, struct request *req, | |
262 | struct request *next) | |
263 | { | |
264 | struct deadline_data *dd = q->elevator->elevator_data; | |
265 | struct deadline_rq *drq = RQ_DATA(req); | |
266 | struct deadline_rq *dnext = RQ_DATA(next); | |
267 | ||
268 | BUG_ON(!drq); | |
269 | BUG_ON(!dnext); | |
270 | ||
1da177e4 LT |
271 | if (rq_rb_key(req) != drq->rb_key) { |
272 | deadline_del_drq_rb(dd, drq); | |
273 | deadline_add_drq_rb(dd, drq); | |
274 | } | |
275 | ||
276 | /* | |
277 | * if dnext expires before drq, assign its expire time to drq | |
278 | * and move into dnext position (dnext will be deleted) in fifo | |
279 | */ | |
280 | if (!list_empty(&drq->fifo) && !list_empty(&dnext->fifo)) { | |
281 | if (time_before(dnext->expires, drq->expires)) { | |
282 | list_move(&drq->fifo, &dnext->fifo); | |
283 | drq->expires = dnext->expires; | |
284 | } | |
285 | } | |
286 | ||
287 | /* | |
288 | * kill knowledge of next, this one is a goner | |
289 | */ | |
290 | deadline_remove_request(q, next); | |
291 | } | |
292 | ||
293 | /* | |
294 | * move request from sort list to dispatch queue. | |
295 | */ | |
296 | static inline void | |
297 | deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq) | |
298 | { | |
299 | request_queue_t *q = drq->request->q; | |
300 | ||
301 | deadline_remove_request(q, drq->request); | |
b4878f24 | 302 | elv_dispatch_add_tail(q, drq->request); |
1da177e4 LT |
303 | } |
304 | ||
305 | /* | |
306 | * move an entry to dispatch queue | |
307 | */ | |
308 | static void | |
309 | deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq) | |
310 | { | |
311 | const int data_dir = rq_data_dir(drq->request); | |
312 | struct rb_node *rbnext = rb_next(&drq->rb_node); | |
313 | ||
314 | dd->next_drq[READ] = NULL; | |
315 | dd->next_drq[WRITE] = NULL; | |
316 | ||
317 | if (rbnext) | |
318 | dd->next_drq[data_dir] = rb_entry_drq(rbnext); | |
319 | ||
320 | dd->last_sector = drq->request->sector + drq->request->nr_sectors; | |
321 | ||
322 | /* | |
323 | * take it off the sort and fifo list, move | |
324 | * to dispatch queue | |
325 | */ | |
326 | deadline_move_to_dispatch(dd, drq); | |
327 | } | |
328 | ||
329 | #define list_entry_fifo(ptr) list_entry((ptr), struct deadline_rq, fifo) | |
330 | ||
331 | /* | |
332 | * deadline_check_fifo returns 0 if there are no expired reads on the fifo, | |
333 | * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir]) | |
334 | */ | |
335 | static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) | |
336 | { | |
337 | struct deadline_rq *drq = list_entry_fifo(dd->fifo_list[ddir].next); | |
338 | ||
339 | /* | |
340 | * drq is expired! | |
341 | */ | |
342 | if (time_after(jiffies, drq->expires)) | |
343 | return 1; | |
344 | ||
345 | return 0; | |
346 | } | |
347 | ||
348 | /* | |
349 | * deadline_dispatch_requests selects the best request according to | |
350 | * read/write expire, fifo_batch, etc | |
351 | */ | |
b4878f24 | 352 | static int deadline_dispatch_requests(request_queue_t *q, int force) |
1da177e4 | 353 | { |
b4878f24 | 354 | struct deadline_data *dd = q->elevator->elevator_data; |
1da177e4 LT |
355 | const int reads = !list_empty(&dd->fifo_list[READ]); |
356 | const int writes = !list_empty(&dd->fifo_list[WRITE]); | |
357 | struct deadline_rq *drq; | |
4b0dc07e | 358 | int data_dir; |
1da177e4 LT |
359 | |
360 | /* | |
361 | * batches are currently reads XOR writes | |
362 | */ | |
9d5c1e1b AM |
363 | if (dd->next_drq[WRITE]) |
364 | drq = dd->next_drq[WRITE]; | |
365 | else | |
366 | drq = dd->next_drq[READ]; | |
1da177e4 LT |
367 | |
368 | if (drq) { | |
369 | /* we have a "next request" */ | |
370 | ||
371 | if (dd->last_sector != drq->request->sector) | |
372 | /* end the batch on a non sequential request */ | |
373 | dd->batching += dd->fifo_batch; | |
374 | ||
375 | if (dd->batching < dd->fifo_batch) | |
376 | /* we are still entitled to batch */ | |
377 | goto dispatch_request; | |
378 | } | |
379 | ||
380 | /* | |
381 | * at this point we are not running a batch. select the appropriate | |
382 | * data direction (read / write) | |
383 | */ | |
384 | ||
385 | if (reads) { | |
dd67d051 | 386 | BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ])); |
1da177e4 LT |
387 | |
388 | if (writes && (dd->starved++ >= dd->writes_starved)) | |
389 | goto dispatch_writes; | |
390 | ||
391 | data_dir = READ; | |
1da177e4 LT |
392 | |
393 | goto dispatch_find_request; | |
394 | } | |
395 | ||
396 | /* | |
397 | * there are either no reads or writes have been starved | |
398 | */ | |
399 | ||
400 | if (writes) { | |
401 | dispatch_writes: | |
dd67d051 | 402 | BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE])); |
1da177e4 LT |
403 | |
404 | dd->starved = 0; | |
405 | ||
406 | data_dir = WRITE; | |
1da177e4 LT |
407 | |
408 | goto dispatch_find_request; | |
409 | } | |
410 | ||
411 | return 0; | |
412 | ||
413 | dispatch_find_request: | |
414 | /* | |
415 | * we are not running a batch, find best request for selected data_dir | |
416 | */ | |
417 | if (deadline_check_fifo(dd, data_dir)) { | |
418 | /* An expired request exists - satisfy it */ | |
419 | dd->batching = 0; | |
420 | drq = list_entry_fifo(dd->fifo_list[data_dir].next); | |
421 | ||
422 | } else if (dd->next_drq[data_dir]) { | |
423 | /* | |
424 | * The last req was the same dir and we have a next request in | |
425 | * sort order. No expired requests so continue on from here. | |
426 | */ | |
427 | drq = dd->next_drq[data_dir]; | |
428 | } else { | |
429 | /* | |
430 | * The last req was the other direction or we have run out of | |
431 | * higher-sectored requests. Go back to the lowest sectored | |
432 | * request (1 way elevator) and start a new batch. | |
433 | */ | |
434 | dd->batching = 0; | |
435 | drq = deadline_find_first_drq(dd, data_dir); | |
436 | } | |
437 | ||
438 | dispatch_request: | |
439 | /* | |
440 | * drq is the selected appropriate request. | |
441 | */ | |
442 | dd->batching++; | |
443 | deadline_move_request(dd, drq); | |
444 | ||
445 | return 1; | |
446 | } | |
447 | ||
1da177e4 LT |
448 | static int deadline_queue_empty(request_queue_t *q) |
449 | { | |
450 | struct deadline_data *dd = q->elevator->elevator_data; | |
451 | ||
b4878f24 JA |
452 | return list_empty(&dd->fifo_list[WRITE]) |
453 | && list_empty(&dd->fifo_list[READ]); | |
1da177e4 LT |
454 | } |
455 | ||
456 | static struct request * | |
457 | deadline_former_request(request_queue_t *q, struct request *rq) | |
458 | { | |
459 | struct deadline_rq *drq = RQ_DATA(rq); | |
460 | struct rb_node *rbprev = rb_prev(&drq->rb_node); | |
461 | ||
462 | if (rbprev) | |
463 | return rb_entry_drq(rbprev)->request; | |
464 | ||
465 | return NULL; | |
466 | } | |
467 | ||
468 | static struct request * | |
469 | deadline_latter_request(request_queue_t *q, struct request *rq) | |
470 | { | |
471 | struct deadline_rq *drq = RQ_DATA(rq); | |
472 | struct rb_node *rbnext = rb_next(&drq->rb_node); | |
473 | ||
474 | if (rbnext) | |
475 | return rb_entry_drq(rbnext)->request; | |
476 | ||
477 | return NULL; | |
478 | } | |
479 | ||
480 | static void deadline_exit_queue(elevator_t *e) | |
481 | { | |
482 | struct deadline_data *dd = e->elevator_data; | |
483 | ||
484 | BUG_ON(!list_empty(&dd->fifo_list[READ])); | |
485 | BUG_ON(!list_empty(&dd->fifo_list[WRITE])); | |
486 | ||
487 | mempool_destroy(dd->drq_pool); | |
1da177e4 LT |
488 | kfree(dd); |
489 | } | |
490 | ||
491 | /* | |
492 | * initialize elevator private data (deadline_data), and alloc a drq for | |
493 | * each request on the free lists | |
494 | */ | |
bc1c1169 | 495 | static void *deadline_init_queue(request_queue_t *q, elevator_t *e) |
1da177e4 LT |
496 | { |
497 | struct deadline_data *dd; | |
1da177e4 LT |
498 | |
499 | if (!drq_pool) | |
bc1c1169 | 500 | return NULL; |
1da177e4 | 501 | |
1946089a | 502 | dd = kmalloc_node(sizeof(*dd), GFP_KERNEL, q->node); |
1da177e4 | 503 | if (!dd) |
bc1c1169 | 504 | return NULL; |
1da177e4 LT |
505 | memset(dd, 0, sizeof(*dd)); |
506 | ||
1946089a CL |
507 | dd->drq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, |
508 | mempool_free_slab, drq_pool, q->node); | |
1da177e4 | 509 | if (!dd->drq_pool) { |
1da177e4 | 510 | kfree(dd); |
bc1c1169 | 511 | return NULL; |
1da177e4 LT |
512 | } |
513 | ||
1da177e4 LT |
514 | INIT_LIST_HEAD(&dd->fifo_list[READ]); |
515 | INIT_LIST_HEAD(&dd->fifo_list[WRITE]); | |
516 | dd->sort_list[READ] = RB_ROOT; | |
517 | dd->sort_list[WRITE] = RB_ROOT; | |
1da177e4 LT |
518 | dd->fifo_expire[READ] = read_expire; |
519 | dd->fifo_expire[WRITE] = write_expire; | |
520 | dd->writes_starved = writes_starved; | |
521 | dd->front_merges = 1; | |
522 | dd->fifo_batch = fifo_batch; | |
bc1c1169 | 523 | return dd; |
1da177e4 LT |
524 | } |
525 | ||
526 | static void deadline_put_request(request_queue_t *q, struct request *rq) | |
527 | { | |
528 | struct deadline_data *dd = q->elevator->elevator_data; | |
529 | struct deadline_rq *drq = RQ_DATA(rq); | |
530 | ||
b4878f24 JA |
531 | mempool_free(drq, dd->drq_pool); |
532 | rq->elevator_private = NULL; | |
1da177e4 LT |
533 | } |
534 | ||
535 | static int | |
22e2c507 | 536 | deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio, |
8267e268 | 537 | gfp_t gfp_mask) |
1da177e4 LT |
538 | { |
539 | struct deadline_data *dd = q->elevator->elevator_data; | |
540 | struct deadline_rq *drq; | |
541 | ||
542 | drq = mempool_alloc(dd->drq_pool, gfp_mask); | |
543 | if (drq) { | |
544 | memset(drq, 0, sizeof(*drq)); | |
dd67d051 | 545 | RB_CLEAR_NODE(&drq->rb_node); |
1da177e4 LT |
546 | drq->request = rq; |
547 | ||
1da177e4 LT |
548 | INIT_LIST_HEAD(&drq->fifo); |
549 | ||
550 | rq->elevator_private = drq; | |
551 | return 0; | |
552 | } | |
553 | ||
554 | return 1; | |
555 | } | |
556 | ||
557 | /* | |
558 | * sysfs parts below | |
559 | */ | |
1da177e4 LT |
560 | |
561 | static ssize_t | |
562 | deadline_var_show(int var, char *page) | |
563 | { | |
564 | return sprintf(page, "%d\n", var); | |
565 | } | |
566 | ||
567 | static ssize_t | |
568 | deadline_var_store(int *var, const char *page, size_t count) | |
569 | { | |
570 | char *p = (char *) page; | |
571 | ||
572 | *var = simple_strtol(p, &p, 10); | |
573 | return count; | |
574 | } | |
575 | ||
576 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ | |
3d1ab40f | 577 | static ssize_t __FUNC(elevator_t *e, char *page) \ |
1da177e4 | 578 | { \ |
3d1ab40f AV |
579 | struct deadline_data *dd = e->elevator_data; \ |
580 | int __data = __VAR; \ | |
1da177e4 LT |
581 | if (__CONV) \ |
582 | __data = jiffies_to_msecs(__data); \ | |
583 | return deadline_var_show(__data, (page)); \ | |
584 | } | |
e572ec7e AV |
585 | SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[READ], 1); |
586 | SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[WRITE], 1); | |
587 | SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0); | |
588 | SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0); | |
589 | SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0); | |
1da177e4 LT |
590 | #undef SHOW_FUNCTION |
591 | ||
592 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
3d1ab40f | 593 | static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ |
1da177e4 | 594 | { \ |
3d1ab40f | 595 | struct deadline_data *dd = e->elevator_data; \ |
1da177e4 LT |
596 | int __data; \ |
597 | int ret = deadline_var_store(&__data, (page), count); \ | |
598 | if (__data < (MIN)) \ | |
599 | __data = (MIN); \ | |
600 | else if (__data > (MAX)) \ | |
601 | __data = (MAX); \ | |
602 | if (__CONV) \ | |
603 | *(__PTR) = msecs_to_jiffies(__data); \ | |
604 | else \ | |
605 | *(__PTR) = __data; \ | |
606 | return ret; \ | |
607 | } | |
e572ec7e AV |
608 | STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1); |
609 | STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1); | |
610 | STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0); | |
611 | STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0); | |
612 | STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0); | |
1da177e4 LT |
613 | #undef STORE_FUNCTION |
614 | ||
e572ec7e AV |
615 | #define DD_ATTR(name) \ |
616 | __ATTR(name, S_IRUGO|S_IWUSR, deadline_##name##_show, \ | |
617 | deadline_##name##_store) | |
618 | ||
619 | static struct elv_fs_entry deadline_attrs[] = { | |
620 | DD_ATTR(read_expire), | |
621 | DD_ATTR(write_expire), | |
622 | DD_ATTR(writes_starved), | |
623 | DD_ATTR(front_merges), | |
624 | DD_ATTR(fifo_batch), | |
625 | __ATTR_NULL | |
1da177e4 LT |
626 | }; |
627 | ||
1da177e4 LT |
628 | static struct elevator_type iosched_deadline = { |
629 | .ops = { | |
630 | .elevator_merge_fn = deadline_merge, | |
631 | .elevator_merged_fn = deadline_merged_request, | |
632 | .elevator_merge_req_fn = deadline_merged_requests, | |
b4878f24 JA |
633 | .elevator_dispatch_fn = deadline_dispatch_requests, |
634 | .elevator_add_req_fn = deadline_add_request, | |
1da177e4 LT |
635 | .elevator_queue_empty_fn = deadline_queue_empty, |
636 | .elevator_former_req_fn = deadline_former_request, | |
637 | .elevator_latter_req_fn = deadline_latter_request, | |
638 | .elevator_set_req_fn = deadline_set_request, | |
639 | .elevator_put_req_fn = deadline_put_request, | |
640 | .elevator_init_fn = deadline_init_queue, | |
641 | .elevator_exit_fn = deadline_exit_queue, | |
642 | }, | |
643 | ||
3d1ab40f | 644 | .elevator_attrs = deadline_attrs, |
1da177e4 LT |
645 | .elevator_name = "deadline", |
646 | .elevator_owner = THIS_MODULE, | |
647 | }; | |
648 | ||
649 | static int __init deadline_init(void) | |
650 | { | |
651 | int ret; | |
652 | ||
653 | drq_pool = kmem_cache_create("deadline_drq", sizeof(struct deadline_rq), | |
654 | 0, 0, NULL, NULL); | |
655 | ||
656 | if (!drq_pool) | |
657 | return -ENOMEM; | |
658 | ||
659 | ret = elv_register(&iosched_deadline); | |
660 | if (ret) | |
661 | kmem_cache_destroy(drq_pool); | |
662 | ||
663 | return ret; | |
664 | } | |
665 | ||
666 | static void __exit deadline_exit(void) | |
667 | { | |
668 | kmem_cache_destroy(drq_pool); | |
669 | elv_unregister(&iosched_deadline); | |
670 | } | |
671 | ||
672 | module_init(deadline_init); | |
673 | module_exit(deadline_exit); | |
674 | ||
675 | MODULE_AUTHOR("Jens Axboe"); | |
676 | MODULE_LICENSE("GPL"); | |
677 | MODULE_DESCRIPTION("deadline IO scheduler"); |