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3dcf60bc | 1 | // SPDX-License-Identifier: GPL-2.0 |
945ffb60 JA |
2 | /* |
3 | * MQ Deadline i/o scheduler - adaptation of the legacy deadline scheduler, | |
4 | * for the blk-mq scheduling framework | |
5 | * | |
6 | * Copyright (C) 2016 Jens Axboe <axboe@kernel.dk> | |
7 | */ | |
8 | #include <linux/kernel.h> | |
9 | #include <linux/fs.h> | |
10 | #include <linux/blkdev.h> | |
11 | #include <linux/blk-mq.h> | |
12 | #include <linux/elevator.h> | |
13 | #include <linux/bio.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/compiler.h> | |
18 | #include <linux/rbtree.h> | |
19 | #include <linux/sbitmap.h> | |
20 | ||
21 | #include "blk.h" | |
22 | #include "blk-mq.h" | |
daaadb3e | 23 | #include "blk-mq-debugfs.h" |
945ffb60 JA |
24 | #include "blk-mq-tag.h" |
25 | #include "blk-mq-sched.h" | |
26 | ||
27 | /* | |
898bd37a | 28 | * See Documentation/block/deadline-iosched.rst |
945ffb60 JA |
29 | */ |
30 | static const int read_expire = HZ / 2; /* max time before a read is submitted. */ | |
31 | static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */ | |
32 | static const int writes_starved = 2; /* max times reads can starve a write */ | |
33 | static const int fifo_batch = 16; /* # of sequential requests treated as one | |
34 | by the above parameters. For throughput. */ | |
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 request *next_rq[2]; | |
51 | unsigned int batching; /* number of sequential requests made */ | |
52 | unsigned int starved; /* times reads have starved writes */ | |
53 | ||
54 | /* | |
55 | * settings that change how the i/o scheduler behaves | |
56 | */ | |
57 | int fifo_expire[2]; | |
58 | int fifo_batch; | |
59 | int writes_starved; | |
60 | int front_merges; | |
61 | ||
62 | spinlock_t lock; | |
5700f691 | 63 | spinlock_t zone_lock; |
945ffb60 JA |
64 | struct list_head dispatch; |
65 | }; | |
66 | ||
67 | static inline struct rb_root * | |
68 | deadline_rb_root(struct deadline_data *dd, struct request *rq) | |
69 | { | |
70 | return &dd->sort_list[rq_data_dir(rq)]; | |
71 | } | |
72 | ||
73 | /* | |
74 | * get the request after `rq' in sector-sorted order | |
75 | */ | |
76 | static inline struct request * | |
77 | deadline_latter_request(struct request *rq) | |
78 | { | |
79 | struct rb_node *node = rb_next(&rq->rb_node); | |
80 | ||
81 | if (node) | |
82 | return rb_entry_rq(node); | |
83 | ||
84 | return NULL; | |
85 | } | |
86 | ||
87 | static void | |
88 | deadline_add_rq_rb(struct deadline_data *dd, struct request *rq) | |
89 | { | |
90 | struct rb_root *root = deadline_rb_root(dd, rq); | |
91 | ||
92 | elv_rb_add(root, rq); | |
93 | } | |
94 | ||
95 | static inline void | |
96 | deadline_del_rq_rb(struct deadline_data *dd, struct request *rq) | |
97 | { | |
98 | const int data_dir = rq_data_dir(rq); | |
99 | ||
100 | if (dd->next_rq[data_dir] == rq) | |
101 | dd->next_rq[data_dir] = deadline_latter_request(rq); | |
102 | ||
103 | elv_rb_del(deadline_rb_root(dd, rq), rq); | |
104 | } | |
105 | ||
106 | /* | |
107 | * remove rq from rbtree and fifo. | |
108 | */ | |
109 | static void deadline_remove_request(struct request_queue *q, struct request *rq) | |
110 | { | |
111 | struct deadline_data *dd = q->elevator->elevator_data; | |
112 | ||
113 | list_del_init(&rq->queuelist); | |
114 | ||
115 | /* | |
116 | * We might not be on the rbtree, if we are doing an insert merge | |
117 | */ | |
118 | if (!RB_EMPTY_NODE(&rq->rb_node)) | |
119 | deadline_del_rq_rb(dd, rq); | |
120 | ||
121 | elv_rqhash_del(q, rq); | |
122 | if (q->last_merge == rq) | |
123 | q->last_merge = NULL; | |
124 | } | |
125 | ||
126 | static void dd_request_merged(struct request_queue *q, struct request *req, | |
34fe7c05 | 127 | enum elv_merge type) |
945ffb60 JA |
128 | { |
129 | struct deadline_data *dd = q->elevator->elevator_data; | |
130 | ||
131 | /* | |
132 | * if the merge was a front merge, we need to reposition request | |
133 | */ | |
134 | if (type == ELEVATOR_FRONT_MERGE) { | |
135 | elv_rb_del(deadline_rb_root(dd, req), req); | |
136 | deadline_add_rq_rb(dd, req); | |
137 | } | |
138 | } | |
139 | ||
140 | static void dd_merged_requests(struct request_queue *q, struct request *req, | |
141 | struct request *next) | |
142 | { | |
143 | /* | |
144 | * if next expires before rq, assign its expire time to rq | |
145 | * and move into next position (next will be deleted) in fifo | |
146 | */ | |
147 | if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) { | |
148 | if (time_before((unsigned long)next->fifo_time, | |
149 | (unsigned long)req->fifo_time)) { | |
150 | list_move(&req->queuelist, &next->queuelist); | |
151 | req->fifo_time = next->fifo_time; | |
152 | } | |
153 | } | |
154 | ||
155 | /* | |
156 | * kill knowledge of next, this one is a goner | |
157 | */ | |
158 | deadline_remove_request(q, next); | |
159 | } | |
160 | ||
161 | /* | |
162 | * move an entry to dispatch queue | |
163 | */ | |
164 | static void | |
165 | deadline_move_request(struct deadline_data *dd, struct request *rq) | |
166 | { | |
167 | const int data_dir = rq_data_dir(rq); | |
168 | ||
169 | dd->next_rq[READ] = NULL; | |
170 | dd->next_rq[WRITE] = NULL; | |
171 | dd->next_rq[data_dir] = deadline_latter_request(rq); | |
172 | ||
173 | /* | |
174 | * take it off the sort and fifo list | |
175 | */ | |
176 | deadline_remove_request(rq->q, rq); | |
177 | } | |
178 | ||
179 | /* | |
180 | * deadline_check_fifo returns 0 if there are no expired requests on the fifo, | |
181 | * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir]) | |
182 | */ | |
183 | static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) | |
184 | { | |
185 | struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next); | |
186 | ||
187 | /* | |
188 | * rq is expired! | |
189 | */ | |
190 | if (time_after_eq(jiffies, (unsigned long)rq->fifo_time)) | |
191 | return 1; | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
bf09ce56 DLM |
196 | /* |
197 | * For the specified data direction, return the next request to | |
198 | * dispatch using arrival ordered lists. | |
199 | */ | |
200 | static struct request * | |
201 | deadline_fifo_request(struct deadline_data *dd, int data_dir) | |
202 | { | |
5700f691 DLM |
203 | struct request *rq; |
204 | unsigned long flags; | |
205 | ||
bf09ce56 DLM |
206 | if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE)) |
207 | return NULL; | |
208 | ||
209 | if (list_empty(&dd->fifo_list[data_dir])) | |
210 | return NULL; | |
211 | ||
5700f691 DLM |
212 | rq = rq_entry_fifo(dd->fifo_list[data_dir].next); |
213 | if (data_dir == READ || !blk_queue_is_zoned(rq->q)) | |
214 | return rq; | |
215 | ||
216 | /* | |
217 | * Look for a write request that can be dispatched, that is one with | |
218 | * an unlocked target zone. | |
219 | */ | |
220 | spin_lock_irqsave(&dd->zone_lock, flags); | |
221 | list_for_each_entry(rq, &dd->fifo_list[WRITE], queuelist) { | |
222 | if (blk_req_can_dispatch_to_zone(rq)) | |
223 | goto out; | |
224 | } | |
225 | rq = NULL; | |
226 | out: | |
227 | spin_unlock_irqrestore(&dd->zone_lock, flags); | |
228 | ||
229 | return rq; | |
bf09ce56 DLM |
230 | } |
231 | ||
232 | /* | |
233 | * For the specified data direction, return the next request to | |
234 | * dispatch using sector position sorted lists. | |
235 | */ | |
236 | static struct request * | |
237 | deadline_next_request(struct deadline_data *dd, int data_dir) | |
238 | { | |
5700f691 DLM |
239 | struct request *rq; |
240 | unsigned long flags; | |
241 | ||
bf09ce56 DLM |
242 | if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE)) |
243 | return NULL; | |
244 | ||
5700f691 DLM |
245 | rq = dd->next_rq[data_dir]; |
246 | if (!rq) | |
247 | return NULL; | |
248 | ||
249 | if (data_dir == READ || !blk_queue_is_zoned(rq->q)) | |
250 | return rq; | |
251 | ||
252 | /* | |
253 | * Look for a write request that can be dispatched, that is one with | |
254 | * an unlocked target zone. | |
255 | */ | |
256 | spin_lock_irqsave(&dd->zone_lock, flags); | |
257 | while (rq) { | |
258 | if (blk_req_can_dispatch_to_zone(rq)) | |
259 | break; | |
260 | rq = deadline_latter_request(rq); | |
261 | } | |
262 | spin_unlock_irqrestore(&dd->zone_lock, flags); | |
263 | ||
264 | return rq; | |
bf09ce56 DLM |
265 | } |
266 | ||
945ffb60 JA |
267 | /* |
268 | * deadline_dispatch_requests selects the best request according to | |
269 | * read/write expire, fifo_batch, etc | |
270 | */ | |
ca11f209 | 271 | static struct request *__dd_dispatch_request(struct deadline_data *dd) |
945ffb60 | 272 | { |
bf09ce56 | 273 | struct request *rq, *next_rq; |
945ffb60 JA |
274 | bool reads, writes; |
275 | int data_dir; | |
276 | ||
277 | if (!list_empty(&dd->dispatch)) { | |
278 | rq = list_first_entry(&dd->dispatch, struct request, queuelist); | |
279 | list_del_init(&rq->queuelist); | |
280 | goto done; | |
281 | } | |
282 | ||
283 | reads = !list_empty(&dd->fifo_list[READ]); | |
284 | writes = !list_empty(&dd->fifo_list[WRITE]); | |
285 | ||
286 | /* | |
287 | * batches are currently reads XOR writes | |
288 | */ | |
bf09ce56 DLM |
289 | rq = deadline_next_request(dd, WRITE); |
290 | if (!rq) | |
291 | rq = deadline_next_request(dd, READ); | |
945ffb60 JA |
292 | |
293 | if (rq && dd->batching < dd->fifo_batch) | |
294 | /* we have a next request are still entitled to batch */ | |
295 | goto dispatch_request; | |
296 | ||
297 | /* | |
298 | * at this point we are not running a batch. select the appropriate | |
299 | * data direction (read / write) | |
300 | */ | |
301 | ||
302 | if (reads) { | |
303 | BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ])); | |
304 | ||
5700f691 DLM |
305 | if (deadline_fifo_request(dd, WRITE) && |
306 | (dd->starved++ >= dd->writes_starved)) | |
945ffb60 JA |
307 | goto dispatch_writes; |
308 | ||
309 | data_dir = READ; | |
310 | ||
311 | goto dispatch_find_request; | |
312 | } | |
313 | ||
314 | /* | |
315 | * there are either no reads or writes have been starved | |
316 | */ | |
317 | ||
318 | if (writes) { | |
319 | dispatch_writes: | |
320 | BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE])); | |
321 | ||
322 | dd->starved = 0; | |
323 | ||
324 | data_dir = WRITE; | |
325 | ||
326 | goto dispatch_find_request; | |
327 | } | |
328 | ||
329 | return NULL; | |
330 | ||
331 | dispatch_find_request: | |
332 | /* | |
333 | * we are not running a batch, find best request for selected data_dir | |
334 | */ | |
bf09ce56 DLM |
335 | next_rq = deadline_next_request(dd, data_dir); |
336 | if (deadline_check_fifo(dd, data_dir) || !next_rq) { | |
945ffb60 JA |
337 | /* |
338 | * A deadline has expired, the last request was in the other | |
339 | * direction, or we have run out of higher-sectored requests. | |
340 | * Start again from the request with the earliest expiry time. | |
341 | */ | |
bf09ce56 | 342 | rq = deadline_fifo_request(dd, data_dir); |
945ffb60 JA |
343 | } else { |
344 | /* | |
345 | * The last req was the same dir and we have a next request in | |
346 | * sort order. No expired requests so continue on from here. | |
347 | */ | |
bf09ce56 | 348 | rq = next_rq; |
945ffb60 JA |
349 | } |
350 | ||
5700f691 DLM |
351 | /* |
352 | * For a zoned block device, if we only have writes queued and none of | |
353 | * them can be dispatched, rq will be NULL. | |
354 | */ | |
355 | if (!rq) | |
356 | return NULL; | |
357 | ||
945ffb60 JA |
358 | dd->batching = 0; |
359 | ||
360 | dispatch_request: | |
361 | /* | |
362 | * rq is the selected appropriate request. | |
363 | */ | |
364 | dd->batching++; | |
365 | deadline_move_request(dd, rq); | |
366 | done: | |
5700f691 DLM |
367 | /* |
368 | * If the request needs its target zone locked, do it. | |
369 | */ | |
370 | blk_req_zone_write_lock(rq); | |
945ffb60 JA |
371 | rq->rq_flags |= RQF_STARTED; |
372 | return rq; | |
373 | } | |
374 | ||
ca11f209 JA |
375 | /* |
376 | * One confusing aspect here is that we get called for a specific | |
7211aef8 | 377 | * hardware queue, but we may return a request that is for a |
ca11f209 JA |
378 | * different hardware queue. This is because mq-deadline has shared |
379 | * state for all hardware queues, in terms of sorting, FIFOs, etc. | |
380 | */ | |
c13660a0 | 381 | static struct request *dd_dispatch_request(struct blk_mq_hw_ctx *hctx) |
945ffb60 JA |
382 | { |
383 | struct deadline_data *dd = hctx->queue->elevator->elevator_data; | |
c13660a0 | 384 | struct request *rq; |
945ffb60 JA |
385 | |
386 | spin_lock(&dd->lock); | |
ca11f209 | 387 | rq = __dd_dispatch_request(dd); |
945ffb60 | 388 | spin_unlock(&dd->lock); |
c13660a0 JA |
389 | |
390 | return rq; | |
945ffb60 JA |
391 | } |
392 | ||
393 | static void dd_exit_queue(struct elevator_queue *e) | |
394 | { | |
395 | struct deadline_data *dd = e->elevator_data; | |
396 | ||
397 | BUG_ON(!list_empty(&dd->fifo_list[READ])); | |
398 | BUG_ON(!list_empty(&dd->fifo_list[WRITE])); | |
399 | ||
400 | kfree(dd); | |
401 | } | |
402 | ||
403 | /* | |
404 | * initialize elevator private data (deadline_data). | |
405 | */ | |
406 | static int dd_init_queue(struct request_queue *q, struct elevator_type *e) | |
407 | { | |
408 | struct deadline_data *dd; | |
409 | struct elevator_queue *eq; | |
410 | ||
411 | eq = elevator_alloc(q, e); | |
412 | if (!eq) | |
413 | return -ENOMEM; | |
414 | ||
415 | dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node); | |
416 | if (!dd) { | |
417 | kobject_put(&eq->kobj); | |
418 | return -ENOMEM; | |
419 | } | |
420 | eq->elevator_data = dd; | |
421 | ||
422 | INIT_LIST_HEAD(&dd->fifo_list[READ]); | |
423 | INIT_LIST_HEAD(&dd->fifo_list[WRITE]); | |
424 | dd->sort_list[READ] = RB_ROOT; | |
425 | dd->sort_list[WRITE] = RB_ROOT; | |
426 | dd->fifo_expire[READ] = read_expire; | |
427 | dd->fifo_expire[WRITE] = write_expire; | |
428 | dd->writes_starved = writes_starved; | |
429 | dd->front_merges = 1; | |
430 | dd->fifo_batch = fifo_batch; | |
431 | spin_lock_init(&dd->lock); | |
5700f691 | 432 | spin_lock_init(&dd->zone_lock); |
945ffb60 JA |
433 | INIT_LIST_HEAD(&dd->dispatch); |
434 | ||
435 | q->elevator = eq; | |
436 | return 0; | |
437 | } | |
438 | ||
439 | static int dd_request_merge(struct request_queue *q, struct request **rq, | |
440 | struct bio *bio) | |
441 | { | |
442 | struct deadline_data *dd = q->elevator->elevator_data; | |
443 | sector_t sector = bio_end_sector(bio); | |
444 | struct request *__rq; | |
445 | ||
446 | if (!dd->front_merges) | |
447 | return ELEVATOR_NO_MERGE; | |
448 | ||
449 | __rq = elv_rb_find(&dd->sort_list[bio_data_dir(bio)], sector); | |
450 | if (__rq) { | |
451 | BUG_ON(sector != blk_rq_pos(__rq)); | |
452 | ||
453 | if (elv_bio_merge_ok(__rq, bio)) { | |
454 | *rq = __rq; | |
455 | return ELEVATOR_FRONT_MERGE; | |
456 | } | |
457 | } | |
458 | ||
459 | return ELEVATOR_NO_MERGE; | |
460 | } | |
461 | ||
14ccb66b CH |
462 | static bool dd_bio_merge(struct blk_mq_hw_ctx *hctx, struct bio *bio, |
463 | unsigned int nr_segs) | |
945ffb60 JA |
464 | { |
465 | struct request_queue *q = hctx->queue; | |
466 | struct deadline_data *dd = q->elevator->elevator_data; | |
e4d750c9 JA |
467 | struct request *free = NULL; |
468 | bool ret; | |
945ffb60 JA |
469 | |
470 | spin_lock(&dd->lock); | |
14ccb66b | 471 | ret = blk_mq_sched_try_merge(q, bio, nr_segs, &free); |
945ffb60 JA |
472 | spin_unlock(&dd->lock); |
473 | ||
e4d750c9 JA |
474 | if (free) |
475 | blk_mq_free_request(free); | |
476 | ||
945ffb60 JA |
477 | return ret; |
478 | } | |
479 | ||
480 | /* | |
481 | * add rq to rbtree and fifo | |
482 | */ | |
483 | static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, | |
484 | bool at_head) | |
485 | { | |
486 | struct request_queue *q = hctx->queue; | |
487 | struct deadline_data *dd = q->elevator->elevator_data; | |
488 | const int data_dir = rq_data_dir(rq); | |
489 | ||
5700f691 DLM |
490 | /* |
491 | * This may be a requeue of a write request that has locked its | |
492 | * target zone. If it is the case, this releases the zone lock. | |
493 | */ | |
494 | blk_req_zone_write_unlock(rq); | |
495 | ||
945ffb60 JA |
496 | if (blk_mq_sched_try_insert_merge(q, rq)) |
497 | return; | |
498 | ||
499 | blk_mq_sched_request_inserted(rq); | |
500 | ||
57292b58 | 501 | if (at_head || blk_rq_is_passthrough(rq)) { |
945ffb60 JA |
502 | if (at_head) |
503 | list_add(&rq->queuelist, &dd->dispatch); | |
504 | else | |
505 | list_add_tail(&rq->queuelist, &dd->dispatch); | |
506 | } else { | |
507 | deadline_add_rq_rb(dd, rq); | |
508 | ||
509 | if (rq_mergeable(rq)) { | |
510 | elv_rqhash_add(q, rq); | |
511 | if (!q->last_merge) | |
512 | q->last_merge = rq; | |
513 | } | |
514 | ||
515 | /* | |
516 | * set expire time and add to fifo list | |
517 | */ | |
518 | rq->fifo_time = jiffies + dd->fifo_expire[data_dir]; | |
519 | list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]); | |
520 | } | |
521 | } | |
522 | ||
523 | static void dd_insert_requests(struct blk_mq_hw_ctx *hctx, | |
524 | struct list_head *list, bool at_head) | |
525 | { | |
526 | struct request_queue *q = hctx->queue; | |
527 | struct deadline_data *dd = q->elevator->elevator_data; | |
528 | ||
529 | spin_lock(&dd->lock); | |
530 | while (!list_empty(list)) { | |
531 | struct request *rq; | |
532 | ||
533 | rq = list_first_entry(list, struct request, queuelist); | |
534 | list_del_init(&rq->queuelist); | |
535 | dd_insert_request(hctx, rq, at_head); | |
536 | } | |
537 | spin_unlock(&dd->lock); | |
538 | } | |
539 | ||
f3bc78d2 DLM |
540 | /* |
541 | * Nothing to do here. This is defined only to ensure that .finish_request | |
542 | * method is called upon request completion. | |
543 | */ | |
544 | static void dd_prepare_request(struct request *rq, struct bio *bio) | |
545 | { | |
546 | } | |
547 | ||
5700f691 DLM |
548 | /* |
549 | * For zoned block devices, write unlock the target zone of | |
550 | * completed write requests. Do this while holding the zone lock | |
551 | * spinlock so that the zone is never unlocked while deadline_fifo_request() | |
f3bc78d2 DLM |
552 | * or deadline_next_request() are executing. This function is called for |
553 | * all requests, whether or not these requests complete successfully. | |
cb8acabb DLM |
554 | * |
555 | * For a zoned block device, __dd_dispatch_request() may have stopped | |
556 | * dispatching requests if all the queued requests are write requests directed | |
557 | * at zones that are already locked due to on-going write requests. To ensure | |
558 | * write request dispatch progress in this case, mark the queue as needing a | |
559 | * restart to ensure that the queue is run again after completion of the | |
560 | * request and zones being unlocked. | |
5700f691 | 561 | */ |
f3bc78d2 | 562 | static void dd_finish_request(struct request *rq) |
5700f691 DLM |
563 | { |
564 | struct request_queue *q = rq->q; | |
565 | ||
566 | if (blk_queue_is_zoned(q)) { | |
567 | struct deadline_data *dd = q->elevator->elevator_data; | |
568 | unsigned long flags; | |
569 | ||
570 | spin_lock_irqsave(&dd->zone_lock, flags); | |
571 | blk_req_zone_write_unlock(rq); | |
cb8acabb DLM |
572 | if (!list_empty(&dd->fifo_list[WRITE])) |
573 | blk_mq_sched_mark_restart_hctx(rq->mq_hctx); | |
5700f691 DLM |
574 | spin_unlock_irqrestore(&dd->zone_lock, flags); |
575 | } | |
576 | } | |
577 | ||
945ffb60 JA |
578 | static bool dd_has_work(struct blk_mq_hw_ctx *hctx) |
579 | { | |
580 | struct deadline_data *dd = hctx->queue->elevator->elevator_data; | |
581 | ||
582 | return !list_empty_careful(&dd->dispatch) || | |
583 | !list_empty_careful(&dd->fifo_list[0]) || | |
584 | !list_empty_careful(&dd->fifo_list[1]); | |
585 | } | |
586 | ||
587 | /* | |
588 | * sysfs parts below | |
589 | */ | |
590 | static ssize_t | |
591 | deadline_var_show(int var, char *page) | |
592 | { | |
593 | return sprintf(page, "%d\n", var); | |
594 | } | |
595 | ||
235f8da1 | 596 | static void |
597 | deadline_var_store(int *var, const char *page) | |
945ffb60 JA |
598 | { |
599 | char *p = (char *) page; | |
600 | ||
601 | *var = simple_strtol(p, &p, 10); | |
945ffb60 JA |
602 | } |
603 | ||
604 | #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ | |
605 | static ssize_t __FUNC(struct elevator_queue *e, char *page) \ | |
606 | { \ | |
607 | struct deadline_data *dd = e->elevator_data; \ | |
608 | int __data = __VAR; \ | |
609 | if (__CONV) \ | |
610 | __data = jiffies_to_msecs(__data); \ | |
611 | return deadline_var_show(__data, (page)); \ | |
612 | } | |
613 | SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[READ], 1); | |
614 | SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[WRITE], 1); | |
615 | SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0); | |
616 | SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0); | |
617 | SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0); | |
618 | #undef SHOW_FUNCTION | |
619 | ||
620 | #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ | |
621 | static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ | |
622 | { \ | |
623 | struct deadline_data *dd = e->elevator_data; \ | |
624 | int __data; \ | |
235f8da1 | 625 | deadline_var_store(&__data, (page)); \ |
945ffb60 JA |
626 | if (__data < (MIN)) \ |
627 | __data = (MIN); \ | |
628 | else if (__data > (MAX)) \ | |
629 | __data = (MAX); \ | |
630 | if (__CONV) \ | |
631 | *(__PTR) = msecs_to_jiffies(__data); \ | |
632 | else \ | |
633 | *(__PTR) = __data; \ | |
235f8da1 | 634 | return count; \ |
945ffb60 JA |
635 | } |
636 | STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1); | |
637 | STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1); | |
638 | STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0); | |
639 | STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0); | |
640 | STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0); | |
641 | #undef STORE_FUNCTION | |
642 | ||
643 | #define DD_ATTR(name) \ | |
5657a819 | 644 | __ATTR(name, 0644, deadline_##name##_show, deadline_##name##_store) |
945ffb60 JA |
645 | |
646 | static struct elv_fs_entry deadline_attrs[] = { | |
647 | DD_ATTR(read_expire), | |
648 | DD_ATTR(write_expire), | |
649 | DD_ATTR(writes_starved), | |
650 | DD_ATTR(front_merges), | |
651 | DD_ATTR(fifo_batch), | |
652 | __ATTR_NULL | |
653 | }; | |
654 | ||
daaadb3e OS |
655 | #ifdef CONFIG_BLK_DEBUG_FS |
656 | #define DEADLINE_DEBUGFS_DDIR_ATTRS(ddir, name) \ | |
657 | static void *deadline_##name##_fifo_start(struct seq_file *m, \ | |
658 | loff_t *pos) \ | |
659 | __acquires(&dd->lock) \ | |
660 | { \ | |
661 | struct request_queue *q = m->private; \ | |
662 | struct deadline_data *dd = q->elevator->elevator_data; \ | |
663 | \ | |
664 | spin_lock(&dd->lock); \ | |
665 | return seq_list_start(&dd->fifo_list[ddir], *pos); \ | |
666 | } \ | |
667 | \ | |
668 | static void *deadline_##name##_fifo_next(struct seq_file *m, void *v, \ | |
669 | loff_t *pos) \ | |
670 | { \ | |
671 | struct request_queue *q = m->private; \ | |
672 | struct deadline_data *dd = q->elevator->elevator_data; \ | |
673 | \ | |
674 | return seq_list_next(v, &dd->fifo_list[ddir], pos); \ | |
675 | } \ | |
676 | \ | |
677 | static void deadline_##name##_fifo_stop(struct seq_file *m, void *v) \ | |
678 | __releases(&dd->lock) \ | |
679 | { \ | |
680 | struct request_queue *q = m->private; \ | |
681 | struct deadline_data *dd = q->elevator->elevator_data; \ | |
682 | \ | |
683 | spin_unlock(&dd->lock); \ | |
684 | } \ | |
685 | \ | |
686 | static const struct seq_operations deadline_##name##_fifo_seq_ops = { \ | |
687 | .start = deadline_##name##_fifo_start, \ | |
688 | .next = deadline_##name##_fifo_next, \ | |
689 | .stop = deadline_##name##_fifo_stop, \ | |
690 | .show = blk_mq_debugfs_rq_show, \ | |
691 | }; \ | |
692 | \ | |
693 | static int deadline_##name##_next_rq_show(void *data, \ | |
694 | struct seq_file *m) \ | |
695 | { \ | |
696 | struct request_queue *q = data; \ | |
697 | struct deadline_data *dd = q->elevator->elevator_data; \ | |
698 | struct request *rq = dd->next_rq[ddir]; \ | |
699 | \ | |
700 | if (rq) \ | |
701 | __blk_mq_debugfs_rq_show(m, rq); \ | |
702 | return 0; \ | |
703 | } | |
704 | DEADLINE_DEBUGFS_DDIR_ATTRS(READ, read) | |
705 | DEADLINE_DEBUGFS_DDIR_ATTRS(WRITE, write) | |
706 | #undef DEADLINE_DEBUGFS_DDIR_ATTRS | |
707 | ||
708 | static int deadline_batching_show(void *data, struct seq_file *m) | |
709 | { | |
710 | struct request_queue *q = data; | |
711 | struct deadline_data *dd = q->elevator->elevator_data; | |
712 | ||
713 | seq_printf(m, "%u\n", dd->batching); | |
714 | return 0; | |
715 | } | |
716 | ||
717 | static int deadline_starved_show(void *data, struct seq_file *m) | |
718 | { | |
719 | struct request_queue *q = data; | |
720 | struct deadline_data *dd = q->elevator->elevator_data; | |
721 | ||
722 | seq_printf(m, "%u\n", dd->starved); | |
723 | return 0; | |
724 | } | |
725 | ||
726 | static void *deadline_dispatch_start(struct seq_file *m, loff_t *pos) | |
727 | __acquires(&dd->lock) | |
728 | { | |
729 | struct request_queue *q = m->private; | |
730 | struct deadline_data *dd = q->elevator->elevator_data; | |
731 | ||
732 | spin_lock(&dd->lock); | |
733 | return seq_list_start(&dd->dispatch, *pos); | |
734 | } | |
735 | ||
736 | static void *deadline_dispatch_next(struct seq_file *m, void *v, loff_t *pos) | |
737 | { | |
738 | struct request_queue *q = m->private; | |
739 | struct deadline_data *dd = q->elevator->elevator_data; | |
740 | ||
741 | return seq_list_next(v, &dd->dispatch, pos); | |
742 | } | |
743 | ||
744 | static void deadline_dispatch_stop(struct seq_file *m, void *v) | |
745 | __releases(&dd->lock) | |
746 | { | |
747 | struct request_queue *q = m->private; | |
748 | struct deadline_data *dd = q->elevator->elevator_data; | |
749 | ||
750 | spin_unlock(&dd->lock); | |
751 | } | |
752 | ||
753 | static const struct seq_operations deadline_dispatch_seq_ops = { | |
754 | .start = deadline_dispatch_start, | |
755 | .next = deadline_dispatch_next, | |
756 | .stop = deadline_dispatch_stop, | |
757 | .show = blk_mq_debugfs_rq_show, | |
758 | }; | |
759 | ||
760 | #define DEADLINE_QUEUE_DDIR_ATTRS(name) \ | |
761 | {#name "_fifo_list", 0400, .seq_ops = &deadline_##name##_fifo_seq_ops}, \ | |
762 | {#name "_next_rq", 0400, deadline_##name##_next_rq_show} | |
763 | static const struct blk_mq_debugfs_attr deadline_queue_debugfs_attrs[] = { | |
764 | DEADLINE_QUEUE_DDIR_ATTRS(read), | |
765 | DEADLINE_QUEUE_DDIR_ATTRS(write), | |
766 | {"batching", 0400, deadline_batching_show}, | |
767 | {"starved", 0400, deadline_starved_show}, | |
768 | {"dispatch", 0400, .seq_ops = &deadline_dispatch_seq_ops}, | |
769 | {}, | |
770 | }; | |
771 | #undef DEADLINE_QUEUE_DDIR_ATTRS | |
772 | #endif | |
773 | ||
945ffb60 | 774 | static struct elevator_type mq_deadline = { |
f9cd4bfe | 775 | .ops = { |
945ffb60 | 776 | .insert_requests = dd_insert_requests, |
c13660a0 | 777 | .dispatch_request = dd_dispatch_request, |
f3bc78d2 DLM |
778 | .prepare_request = dd_prepare_request, |
779 | .finish_request = dd_finish_request, | |
945ffb60 JA |
780 | .next_request = elv_rb_latter_request, |
781 | .former_request = elv_rb_former_request, | |
782 | .bio_merge = dd_bio_merge, | |
783 | .request_merge = dd_request_merge, | |
784 | .requests_merged = dd_merged_requests, | |
785 | .request_merged = dd_request_merged, | |
786 | .has_work = dd_has_work, | |
787 | .init_sched = dd_init_queue, | |
788 | .exit_sched = dd_exit_queue, | |
789 | }, | |
790 | ||
daaadb3e OS |
791 | #ifdef CONFIG_BLK_DEBUG_FS |
792 | .queue_debugfs_attrs = deadline_queue_debugfs_attrs, | |
793 | #endif | |
945ffb60 JA |
794 | .elevator_attrs = deadline_attrs, |
795 | .elevator_name = "mq-deadline", | |
4d740bc9 | 796 | .elevator_alias = "deadline", |
68c43f13 | 797 | .elevator_features = ELEVATOR_F_ZBD_SEQ_WRITE, |
945ffb60 JA |
798 | .elevator_owner = THIS_MODULE, |
799 | }; | |
7de967e7 | 800 | MODULE_ALIAS("mq-deadline-iosched"); |
945ffb60 JA |
801 | |
802 | static int __init deadline_init(void) | |
803 | { | |
804 | return elv_register(&mq_deadline); | |
805 | } | |
806 | ||
807 | static void __exit deadline_exit(void) | |
808 | { | |
809 | elv_unregister(&mq_deadline); | |
810 | } | |
811 | ||
812 | module_init(deadline_init); | |
813 | module_exit(deadline_exit); | |
814 | ||
815 | MODULE_AUTHOR("Jens Axboe"); | |
816 | MODULE_LICENSE("GPL"); | |
817 | MODULE_DESCRIPTION("MQ deadline IO scheduler"); |