Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
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/bio.h>
13 : #include <linux/module.h>
14 : #include <linux/slab.h>
15 : #include <linux/init.h>
16 : #include <linux/compiler.h>
17 : #include <linux/rbtree.h>
18 : #include <linux/sbitmap.h>
19 :
20 : #include <trace/events/block.h>
21 :
22 : #include "elevator.h"
23 : #include "blk.h"
24 : #include "blk-mq.h"
25 : #include "blk-mq-debugfs.h"
26 : #include "blk-mq-tag.h"
27 : #include "blk-mq-sched.h"
28 :
29 : /*
30 : * See Documentation/block/deadline-iosched.rst
31 : */
32 : static const int read_expire = HZ / 2; /* max time before a read is submitted. */
33 : static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
34 : /*
35 : * Time after which to dispatch lower priority requests even if higher
36 : * priority requests are pending.
37 : */
38 : static const int prio_aging_expire = 10 * HZ;
39 : static const int writes_starved = 2; /* max times reads can starve a write */
40 : static const int fifo_batch = 16; /* # of sequential requests treated as one
41 : by the above parameters. For throughput. */
42 :
43 : enum dd_data_dir {
44 : DD_READ = READ,
45 : DD_WRITE = WRITE,
46 : };
47 :
48 : enum { DD_DIR_COUNT = 2 };
49 :
50 : enum dd_prio {
51 : DD_RT_PRIO = 0,
52 : DD_BE_PRIO = 1,
53 : DD_IDLE_PRIO = 2,
54 : DD_PRIO_MAX = 2,
55 : };
56 :
57 : enum { DD_PRIO_COUNT = 3 };
58 :
59 : /*
60 : * I/O statistics per I/O priority. It is fine if these counters overflow.
61 : * What matters is that these counters are at least as wide as
62 : * log2(max_outstanding_requests).
63 : */
64 : struct io_stats_per_prio {
65 : uint32_t inserted;
66 : uint32_t merged;
67 : uint32_t dispatched;
68 : atomic_t completed;
69 : };
70 :
71 : /*
72 : * Deadline scheduler data per I/O priority (enum dd_prio). Requests are
73 : * present on both sort_list[] and fifo_list[].
74 : */
75 : struct dd_per_prio {
76 : struct list_head dispatch;
77 : struct rb_root sort_list[DD_DIR_COUNT];
78 : struct list_head fifo_list[DD_DIR_COUNT];
79 : /* Next request in FIFO order. Read, write or both are NULL. */
80 : struct request *next_rq[DD_DIR_COUNT];
81 : struct io_stats_per_prio stats;
82 : };
83 :
84 : struct deadline_data {
85 : /*
86 : * run time data
87 : */
88 :
89 : struct dd_per_prio per_prio[DD_PRIO_COUNT];
90 :
91 : /* Data direction of latest dispatched request. */
92 : enum dd_data_dir last_dir;
93 : unsigned int batching; /* number of sequential requests made */
94 : unsigned int starved; /* times reads have starved writes */
95 :
96 : /*
97 : * settings that change how the i/o scheduler behaves
98 : */
99 : int fifo_expire[DD_DIR_COUNT];
100 : int fifo_batch;
101 : int writes_starved;
102 : int front_merges;
103 : u32 async_depth;
104 : int prio_aging_expire;
105 :
106 : spinlock_t lock;
107 : spinlock_t zone_lock;
108 : };
109 :
110 : /* Maps an I/O priority class to a deadline scheduler priority. */
111 : static const enum dd_prio ioprio_class_to_prio[] = {
112 : [IOPRIO_CLASS_NONE] = DD_BE_PRIO,
113 : [IOPRIO_CLASS_RT] = DD_RT_PRIO,
114 : [IOPRIO_CLASS_BE] = DD_BE_PRIO,
115 : [IOPRIO_CLASS_IDLE] = DD_IDLE_PRIO,
116 : };
117 :
118 : static inline struct rb_root *
119 : deadline_rb_root(struct dd_per_prio *per_prio, struct request *rq)
120 : {
121 0 : return &per_prio->sort_list[rq_data_dir(rq)];
122 : }
123 :
124 : /*
125 : * Returns the I/O priority class (IOPRIO_CLASS_*) that has been assigned to a
126 : * request.
127 : */
128 : static u8 dd_rq_ioclass(struct request *rq)
129 : {
130 0 : return IOPRIO_PRIO_CLASS(req_get_ioprio(rq));
131 : }
132 :
133 : /*
134 : * get the request before `rq' in sector-sorted order
135 : */
136 : static inline struct request *
137 : deadline_earlier_request(struct request *rq)
138 : {
139 : struct rb_node *node = rb_prev(&rq->rb_node);
140 :
141 : if (node)
142 : return rb_entry_rq(node);
143 :
144 : return NULL;
145 : }
146 :
147 : /*
148 : * get the request after `rq' in sector-sorted order
149 : */
150 : static inline struct request *
151 : deadline_latter_request(struct request *rq)
152 : {
153 0 : struct rb_node *node = rb_next(&rq->rb_node);
154 :
155 0 : if (node)
156 0 : return rb_entry_rq(node);
157 :
158 : return NULL;
159 : }
160 :
161 : static void
162 : deadline_add_rq_rb(struct dd_per_prio *per_prio, struct request *rq)
163 : {
164 0 : struct rb_root *root = deadline_rb_root(per_prio, rq);
165 :
166 0 : elv_rb_add(root, rq);
167 : }
168 :
169 : static inline void
170 0 : deadline_del_rq_rb(struct dd_per_prio *per_prio, struct request *rq)
171 : {
172 0 : const enum dd_data_dir data_dir = rq_data_dir(rq);
173 :
174 0 : if (per_prio->next_rq[data_dir] == rq)
175 0 : per_prio->next_rq[data_dir] = deadline_latter_request(rq);
176 :
177 0 : elv_rb_del(deadline_rb_root(per_prio, rq), rq);
178 0 : }
179 :
180 : /*
181 : * remove rq from rbtree and fifo.
182 : */
183 0 : static void deadline_remove_request(struct request_queue *q,
184 : struct dd_per_prio *per_prio,
185 : struct request *rq)
186 : {
187 0 : list_del_init(&rq->queuelist);
188 :
189 : /*
190 : * We might not be on the rbtree, if we are doing an insert merge
191 : */
192 0 : if (!RB_EMPTY_NODE(&rq->rb_node))
193 0 : deadline_del_rq_rb(per_prio, rq);
194 :
195 0 : elv_rqhash_del(q, rq);
196 0 : if (q->last_merge == rq)
197 0 : q->last_merge = NULL;
198 0 : }
199 :
200 0 : static void dd_request_merged(struct request_queue *q, struct request *req,
201 : enum elv_merge type)
202 : {
203 0 : struct deadline_data *dd = q->elevator->elevator_data;
204 0 : const u8 ioprio_class = dd_rq_ioclass(req);
205 0 : const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
206 0 : struct dd_per_prio *per_prio = &dd->per_prio[prio];
207 :
208 : /*
209 : * if the merge was a front merge, we need to reposition request
210 : */
211 0 : if (type == ELEVATOR_FRONT_MERGE) {
212 0 : elv_rb_del(deadline_rb_root(per_prio, req), req);
213 : deadline_add_rq_rb(per_prio, req);
214 : }
215 0 : }
216 :
217 : /*
218 : * Callback function that is invoked after @next has been merged into @req.
219 : */
220 0 : static void dd_merged_requests(struct request_queue *q, struct request *req,
221 : struct request *next)
222 : {
223 0 : struct deadline_data *dd = q->elevator->elevator_data;
224 0 : const u8 ioprio_class = dd_rq_ioclass(next);
225 0 : const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
226 :
227 : lockdep_assert_held(&dd->lock);
228 :
229 0 : dd->per_prio[prio].stats.merged++;
230 :
231 : /*
232 : * if next expires before rq, assign its expire time to rq
233 : * and move into next position (next will be deleted) in fifo
234 : */
235 0 : if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
236 0 : if (time_before((unsigned long)next->fifo_time,
237 : (unsigned long)req->fifo_time)) {
238 0 : list_move(&req->queuelist, &next->queuelist);
239 0 : req->fifo_time = next->fifo_time;
240 : }
241 : }
242 :
243 : /*
244 : * kill knowledge of next, this one is a goner
245 : */
246 0 : deadline_remove_request(q, &dd->per_prio[prio], next);
247 0 : }
248 :
249 : /*
250 : * move an entry to dispatch queue
251 : */
252 : static void
253 0 : deadline_move_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
254 : struct request *rq)
255 : {
256 0 : const enum dd_data_dir data_dir = rq_data_dir(rq);
257 :
258 0 : per_prio->next_rq[data_dir] = deadline_latter_request(rq);
259 :
260 : /*
261 : * take it off the sort and fifo list
262 : */
263 0 : deadline_remove_request(rq->q, per_prio, rq);
264 0 : }
265 :
266 : /* Number of requests queued for a given priority level. */
267 : static u32 dd_queued(struct deadline_data *dd, enum dd_prio prio)
268 : {
269 0 : const struct io_stats_per_prio *stats = &dd->per_prio[prio].stats;
270 :
271 : lockdep_assert_held(&dd->lock);
272 :
273 0 : return stats->inserted - atomic_read(&stats->completed);
274 : }
275 :
276 : /*
277 : * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
278 : * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
279 : */
280 : static inline int deadline_check_fifo(struct dd_per_prio *per_prio,
281 : enum dd_data_dir data_dir)
282 : {
283 0 : struct request *rq = rq_entry_fifo(per_prio->fifo_list[data_dir].next);
284 :
285 : /*
286 : * rq is expired!
287 : */
288 0 : if (time_after_eq(jiffies, (unsigned long)rq->fifo_time))
289 : return 1;
290 :
291 : return 0;
292 : }
293 :
294 : /*
295 : * Check if rq has a sequential request preceding it.
296 : */
297 : static bool deadline_is_seq_write(struct deadline_data *dd, struct request *rq)
298 : {
299 : struct request *prev = deadline_earlier_request(rq);
300 :
301 : if (!prev)
302 : return false;
303 :
304 : return blk_rq_pos(prev) + blk_rq_sectors(prev) == blk_rq_pos(rq);
305 : }
306 :
307 : /*
308 : * Skip all write requests that are sequential from @rq, even if we cross
309 : * a zone boundary.
310 : */
311 : static struct request *deadline_skip_seq_writes(struct deadline_data *dd,
312 : struct request *rq)
313 : {
314 : sector_t pos = blk_rq_pos(rq);
315 : sector_t skipped_sectors = 0;
316 :
317 : while (rq) {
318 : if (blk_rq_pos(rq) != pos + skipped_sectors)
319 : break;
320 : skipped_sectors += blk_rq_sectors(rq);
321 : rq = deadline_latter_request(rq);
322 : }
323 :
324 : return rq;
325 : }
326 :
327 : /*
328 : * For the specified data direction, return the next request to
329 : * dispatch using arrival ordered lists.
330 : */
331 : static struct request *
332 : deadline_fifo_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
333 : enum dd_data_dir data_dir)
334 : {
335 : struct request *rq;
336 : unsigned long flags;
337 :
338 0 : if (list_empty(&per_prio->fifo_list[data_dir]))
339 : return NULL;
340 :
341 0 : rq = rq_entry_fifo(per_prio->fifo_list[data_dir].next);
342 : if (data_dir == DD_READ || !blk_queue_is_zoned(rq->q))
343 : return rq;
344 :
345 : /*
346 : * Look for a write request that can be dispatched, that is one with
347 : * an unlocked target zone. For some HDDs, breaking a sequential
348 : * write stream can lead to lower throughput, so make sure to preserve
349 : * sequential write streams, even if that stream crosses into the next
350 : * zones and these zones are unlocked.
351 : */
352 : spin_lock_irqsave(&dd->zone_lock, flags);
353 : list_for_each_entry(rq, &per_prio->fifo_list[DD_WRITE], queuelist) {
354 : if (blk_req_can_dispatch_to_zone(rq) &&
355 : (blk_queue_nonrot(rq->q) ||
356 : !deadline_is_seq_write(dd, rq)))
357 : goto out;
358 : }
359 : rq = NULL;
360 : out:
361 : spin_unlock_irqrestore(&dd->zone_lock, flags);
362 :
363 : return rq;
364 : }
365 :
366 : /*
367 : * For the specified data direction, return the next request to
368 : * dispatch using sector position sorted lists.
369 : */
370 : static struct request *
371 : deadline_next_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
372 : enum dd_data_dir data_dir)
373 : {
374 : struct request *rq;
375 : unsigned long flags;
376 :
377 0 : rq = per_prio->next_rq[data_dir];
378 0 : if (!rq)
379 : return NULL;
380 :
381 : if (data_dir == DD_READ || !blk_queue_is_zoned(rq->q))
382 : return rq;
383 :
384 : /*
385 : * Look for a write request that can be dispatched, that is one with
386 : * an unlocked target zone. For some HDDs, breaking a sequential
387 : * write stream can lead to lower throughput, so make sure to preserve
388 : * sequential write streams, even if that stream crosses into the next
389 : * zones and these zones are unlocked.
390 : */
391 : spin_lock_irqsave(&dd->zone_lock, flags);
392 : while (rq) {
393 : if (blk_req_can_dispatch_to_zone(rq))
394 : break;
395 : if (blk_queue_nonrot(rq->q))
396 : rq = deadline_latter_request(rq);
397 : else
398 : rq = deadline_skip_seq_writes(dd, rq);
399 : }
400 : spin_unlock_irqrestore(&dd->zone_lock, flags);
401 :
402 : return rq;
403 : }
404 :
405 : /*
406 : * Returns true if and only if @rq started after @latest_start where
407 : * @latest_start is in jiffies.
408 : */
409 : static bool started_after(struct deadline_data *dd, struct request *rq,
410 : unsigned long latest_start)
411 : {
412 0 : unsigned long start_time = (unsigned long)rq->fifo_time;
413 :
414 0 : start_time -= dd->fifo_expire[rq_data_dir(rq)];
415 :
416 0 : return time_after(start_time, latest_start);
417 : }
418 :
419 : /*
420 : * deadline_dispatch_requests selects the best request according to
421 : * read/write expire, fifo_batch, etc and with a start time <= @latest_start.
422 : */
423 0 : static struct request *__dd_dispatch_request(struct deadline_data *dd,
424 : struct dd_per_prio *per_prio,
425 : unsigned long latest_start)
426 : {
427 : struct request *rq, *next_rq;
428 : enum dd_data_dir data_dir;
429 : enum dd_prio prio;
430 : u8 ioprio_class;
431 :
432 : lockdep_assert_held(&dd->lock);
433 :
434 0 : if (!list_empty(&per_prio->dispatch)) {
435 0 : rq = list_first_entry(&per_prio->dispatch, struct request,
436 : queuelist);
437 0 : if (started_after(dd, rq, latest_start))
438 : return NULL;
439 0 : list_del_init(&rq->queuelist);
440 : goto done;
441 : }
442 :
443 : /*
444 : * batches are currently reads XOR writes
445 : */
446 0 : rq = deadline_next_request(dd, per_prio, dd->last_dir);
447 0 : if (rq && dd->batching < dd->fifo_batch)
448 : /* we have a next request are still entitled to batch */
449 : goto dispatch_request;
450 :
451 : /*
452 : * at this point we are not running a batch. select the appropriate
453 : * data direction (read / write)
454 : */
455 :
456 0 : if (!list_empty(&per_prio->fifo_list[DD_READ])) {
457 0 : BUG_ON(RB_EMPTY_ROOT(&per_prio->sort_list[DD_READ]));
458 :
459 0 : if (deadline_fifo_request(dd, per_prio, DD_WRITE) &&
460 0 : (dd->starved++ >= dd->writes_starved))
461 : goto dispatch_writes;
462 :
463 : data_dir = DD_READ;
464 :
465 : goto dispatch_find_request;
466 : }
467 :
468 : /*
469 : * there are either no reads or writes have been starved
470 : */
471 :
472 0 : if (!list_empty(&per_prio->fifo_list[DD_WRITE])) {
473 : dispatch_writes:
474 0 : BUG_ON(RB_EMPTY_ROOT(&per_prio->sort_list[DD_WRITE]));
475 :
476 0 : dd->starved = 0;
477 :
478 0 : data_dir = DD_WRITE;
479 :
480 0 : goto dispatch_find_request;
481 : }
482 :
483 : return NULL;
484 :
485 : dispatch_find_request:
486 : /*
487 : * we are not running a batch, find best request for selected data_dir
488 : */
489 0 : next_rq = deadline_next_request(dd, per_prio, data_dir);
490 0 : if (deadline_check_fifo(per_prio, data_dir) || !next_rq) {
491 : /*
492 : * A deadline has expired, the last request was in the other
493 : * direction, or we have run out of higher-sectored requests.
494 : * Start again from the request with the earliest expiry time.
495 : */
496 0 : rq = deadline_fifo_request(dd, per_prio, data_dir);
497 : } else {
498 : /*
499 : * The last req was the same dir and we have a next request in
500 : * sort order. No expired requests so continue on from here.
501 : */
502 : rq = next_rq;
503 : }
504 :
505 : /*
506 : * For a zoned block device, if we only have writes queued and none of
507 : * them can be dispatched, rq will be NULL.
508 : */
509 0 : if (!rq)
510 : return NULL;
511 :
512 0 : dd->last_dir = data_dir;
513 0 : dd->batching = 0;
514 :
515 : dispatch_request:
516 0 : if (started_after(dd, rq, latest_start))
517 : return NULL;
518 :
519 : /*
520 : * rq is the selected appropriate request.
521 : */
522 0 : dd->batching++;
523 0 : deadline_move_request(dd, per_prio, rq);
524 : done:
525 0 : ioprio_class = dd_rq_ioclass(rq);
526 0 : prio = ioprio_class_to_prio[ioprio_class];
527 0 : dd->per_prio[prio].stats.dispatched++;
528 : /*
529 : * If the request needs its target zone locked, do it.
530 : */
531 0 : blk_req_zone_write_lock(rq);
532 0 : rq->rq_flags |= RQF_STARTED;
533 0 : return rq;
534 : }
535 :
536 : /*
537 : * Check whether there are any requests with priority other than DD_RT_PRIO
538 : * that were inserted more than prio_aging_expire jiffies ago.
539 : */
540 0 : static struct request *dd_dispatch_prio_aged_requests(struct deadline_data *dd,
541 : unsigned long now)
542 : {
543 : struct request *rq;
544 : enum dd_prio prio;
545 : int prio_cnt;
546 :
547 : lockdep_assert_held(&dd->lock);
548 :
549 0 : prio_cnt = !!dd_queued(dd, DD_RT_PRIO) + !!dd_queued(dd, DD_BE_PRIO) +
550 0 : !!dd_queued(dd, DD_IDLE_PRIO);
551 0 : if (prio_cnt < 2)
552 : return NULL;
553 :
554 0 : for (prio = DD_BE_PRIO; prio <= DD_PRIO_MAX; prio++) {
555 0 : rq = __dd_dispatch_request(dd, &dd->per_prio[prio],
556 0 : now - dd->prio_aging_expire);
557 0 : if (rq)
558 : return rq;
559 : }
560 :
561 : return NULL;
562 : }
563 :
564 : /*
565 : * Called from blk_mq_run_hw_queue() -> __blk_mq_sched_dispatch_requests().
566 : *
567 : * One confusing aspect here is that we get called for a specific
568 : * hardware queue, but we may return a request that is for a
569 : * different hardware queue. This is because mq-deadline has shared
570 : * state for all hardware queues, in terms of sorting, FIFOs, etc.
571 : */
572 0 : static struct request *dd_dispatch_request(struct blk_mq_hw_ctx *hctx)
573 : {
574 0 : struct deadline_data *dd = hctx->queue->elevator->elevator_data;
575 0 : const unsigned long now = jiffies;
576 : struct request *rq;
577 : enum dd_prio prio;
578 :
579 0 : spin_lock(&dd->lock);
580 0 : rq = dd_dispatch_prio_aged_requests(dd, now);
581 0 : if (rq)
582 : goto unlock;
583 :
584 : /*
585 : * Next, dispatch requests in priority order. Ignore lower priority
586 : * requests if any higher priority requests are pending.
587 : */
588 0 : for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
589 0 : rq = __dd_dispatch_request(dd, &dd->per_prio[prio], now);
590 0 : if (rq || dd_queued(dd, prio))
591 : break;
592 : }
593 :
594 : unlock:
595 0 : spin_unlock(&dd->lock);
596 :
597 0 : return rq;
598 : }
599 :
600 : /*
601 : * Called by __blk_mq_alloc_request(). The shallow_depth value set by this
602 : * function is used by __blk_mq_get_tag().
603 : */
604 0 : static void dd_limit_depth(blk_opf_t opf, struct blk_mq_alloc_data *data)
605 : {
606 0 : struct deadline_data *dd = data->q->elevator->elevator_data;
607 :
608 : /* Do not throttle synchronous reads. */
609 0 : if (op_is_sync(opf) && !op_is_write(opf))
610 : return;
611 :
612 : /*
613 : * Throttle asynchronous requests and writes such that these requests
614 : * do not block the allocation of synchronous requests.
615 : */
616 0 : data->shallow_depth = dd->async_depth;
617 : }
618 :
619 : /* Called by blk_mq_update_nr_requests(). */
620 0 : static void dd_depth_updated(struct blk_mq_hw_ctx *hctx)
621 : {
622 0 : struct request_queue *q = hctx->queue;
623 0 : struct deadline_data *dd = q->elevator->elevator_data;
624 0 : struct blk_mq_tags *tags = hctx->sched_tags;
625 :
626 0 : dd->async_depth = max(1UL, 3 * q->nr_requests / 4);
627 :
628 0 : sbitmap_queue_min_shallow_depth(&tags->bitmap_tags, dd->async_depth);
629 0 : }
630 :
631 : /* Called by blk_mq_init_hctx() and blk_mq_init_sched(). */
632 0 : static int dd_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
633 : {
634 0 : dd_depth_updated(hctx);
635 0 : return 0;
636 : }
637 :
638 0 : static void dd_exit_sched(struct elevator_queue *e)
639 : {
640 0 : struct deadline_data *dd = e->elevator_data;
641 : enum dd_prio prio;
642 :
643 0 : for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
644 0 : struct dd_per_prio *per_prio = &dd->per_prio[prio];
645 0 : const struct io_stats_per_prio *stats = &per_prio->stats;
646 : uint32_t queued;
647 :
648 0 : WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_READ]));
649 0 : WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_WRITE]));
650 :
651 0 : spin_lock(&dd->lock);
652 0 : queued = dd_queued(dd, prio);
653 0 : spin_unlock(&dd->lock);
654 :
655 0 : WARN_ONCE(queued != 0,
656 : "statistics for priority %d: i %u m %u d %u c %u\n",
657 : prio, stats->inserted, stats->merged,
658 : stats->dispatched, atomic_read(&stats->completed));
659 : }
660 :
661 0 : kfree(dd);
662 0 : }
663 :
664 : /*
665 : * initialize elevator private data (deadline_data).
666 : */
667 0 : static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
668 : {
669 : struct deadline_data *dd;
670 : struct elevator_queue *eq;
671 : enum dd_prio prio;
672 0 : int ret = -ENOMEM;
673 :
674 0 : eq = elevator_alloc(q, e);
675 0 : if (!eq)
676 : return ret;
677 :
678 0 : dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
679 0 : if (!dd)
680 : goto put_eq;
681 :
682 0 : eq->elevator_data = dd;
683 :
684 0 : for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
685 0 : struct dd_per_prio *per_prio = &dd->per_prio[prio];
686 :
687 0 : INIT_LIST_HEAD(&per_prio->dispatch);
688 0 : INIT_LIST_HEAD(&per_prio->fifo_list[DD_READ]);
689 0 : INIT_LIST_HEAD(&per_prio->fifo_list[DD_WRITE]);
690 0 : per_prio->sort_list[DD_READ] = RB_ROOT;
691 0 : per_prio->sort_list[DD_WRITE] = RB_ROOT;
692 : }
693 0 : dd->fifo_expire[DD_READ] = read_expire;
694 0 : dd->fifo_expire[DD_WRITE] = write_expire;
695 0 : dd->writes_starved = writes_starved;
696 0 : dd->front_merges = 1;
697 0 : dd->last_dir = DD_WRITE;
698 0 : dd->fifo_batch = fifo_batch;
699 0 : dd->prio_aging_expire = prio_aging_expire;
700 0 : spin_lock_init(&dd->lock);
701 0 : spin_lock_init(&dd->zone_lock);
702 :
703 : /* We dispatch from request queue wide instead of hw queue */
704 0 : blk_queue_flag_set(QUEUE_FLAG_SQ_SCHED, q);
705 :
706 0 : q->elevator = eq;
707 0 : return 0;
708 :
709 : put_eq:
710 0 : kobject_put(&eq->kobj);
711 0 : return ret;
712 : }
713 :
714 : /*
715 : * Try to merge @bio into an existing request. If @bio has been merged into
716 : * an existing request, store the pointer to that request into *@rq.
717 : */
718 0 : static int dd_request_merge(struct request_queue *q, struct request **rq,
719 : struct bio *bio)
720 : {
721 0 : struct deadline_data *dd = q->elevator->elevator_data;
722 0 : const u8 ioprio_class = IOPRIO_PRIO_CLASS(bio->bi_ioprio);
723 0 : const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
724 0 : struct dd_per_prio *per_prio = &dd->per_prio[prio];
725 0 : sector_t sector = bio_end_sector(bio);
726 : struct request *__rq;
727 :
728 0 : if (!dd->front_merges)
729 : return ELEVATOR_NO_MERGE;
730 :
731 0 : __rq = elv_rb_find(&per_prio->sort_list[bio_data_dir(bio)], sector);
732 0 : if (__rq) {
733 0 : BUG_ON(sector != blk_rq_pos(__rq));
734 :
735 0 : if (elv_bio_merge_ok(__rq, bio)) {
736 0 : *rq = __rq;
737 0 : if (blk_discard_mergable(__rq))
738 : return ELEVATOR_DISCARD_MERGE;
739 0 : return ELEVATOR_FRONT_MERGE;
740 : }
741 : }
742 :
743 : return ELEVATOR_NO_MERGE;
744 : }
745 :
746 : /*
747 : * Attempt to merge a bio into an existing request. This function is called
748 : * before @bio is associated with a request.
749 : */
750 0 : static bool dd_bio_merge(struct request_queue *q, struct bio *bio,
751 : unsigned int nr_segs)
752 : {
753 0 : struct deadline_data *dd = q->elevator->elevator_data;
754 0 : struct request *free = NULL;
755 : bool ret;
756 :
757 0 : spin_lock(&dd->lock);
758 0 : ret = blk_mq_sched_try_merge(q, bio, nr_segs, &free);
759 0 : spin_unlock(&dd->lock);
760 :
761 0 : if (free)
762 0 : blk_mq_free_request(free);
763 :
764 0 : return ret;
765 : }
766 :
767 : /*
768 : * add rq to rbtree and fifo
769 : */
770 0 : static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
771 : bool at_head)
772 : {
773 0 : struct request_queue *q = hctx->queue;
774 0 : struct deadline_data *dd = q->elevator->elevator_data;
775 0 : const enum dd_data_dir data_dir = rq_data_dir(rq);
776 0 : u16 ioprio = req_get_ioprio(rq);
777 0 : u8 ioprio_class = IOPRIO_PRIO_CLASS(ioprio);
778 : struct dd_per_prio *per_prio;
779 : enum dd_prio prio;
780 0 : LIST_HEAD(free);
781 :
782 : lockdep_assert_held(&dd->lock);
783 :
784 : /*
785 : * This may be a requeue of a write request that has locked its
786 : * target zone. If it is the case, this releases the zone lock.
787 : */
788 0 : blk_req_zone_write_unlock(rq);
789 :
790 0 : prio = ioprio_class_to_prio[ioprio_class];
791 0 : per_prio = &dd->per_prio[prio];
792 0 : if (!rq->elv.priv[0]) {
793 0 : per_prio->stats.inserted++;
794 0 : rq->elv.priv[0] = (void *)(uintptr_t)1;
795 : }
796 :
797 0 : if (blk_mq_sched_try_insert_merge(q, rq, &free)) {
798 0 : blk_mq_free_requests(&free);
799 0 : return;
800 : }
801 :
802 0 : trace_block_rq_insert(rq);
803 :
804 0 : if (at_head) {
805 0 : list_add(&rq->queuelist, &per_prio->dispatch);
806 0 : rq->fifo_time = jiffies;
807 : } else {
808 0 : deadline_add_rq_rb(per_prio, rq);
809 :
810 0 : if (rq_mergeable(rq)) {
811 0 : elv_rqhash_add(q, rq);
812 0 : if (!q->last_merge)
813 0 : q->last_merge = rq;
814 : }
815 :
816 : /*
817 : * set expire time and add to fifo list
818 : */
819 0 : rq->fifo_time = jiffies + dd->fifo_expire[data_dir];
820 0 : list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]);
821 : }
822 : }
823 :
824 : /*
825 : * Called from blk_mq_sched_insert_request() or blk_mq_sched_insert_requests().
826 : */
827 0 : static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
828 : struct list_head *list, bool at_head)
829 : {
830 0 : struct request_queue *q = hctx->queue;
831 0 : struct deadline_data *dd = q->elevator->elevator_data;
832 :
833 0 : spin_lock(&dd->lock);
834 0 : while (!list_empty(list)) {
835 : struct request *rq;
836 :
837 0 : rq = list_first_entry(list, struct request, queuelist);
838 0 : list_del_init(&rq->queuelist);
839 0 : dd_insert_request(hctx, rq, at_head);
840 : }
841 0 : spin_unlock(&dd->lock);
842 0 : }
843 :
844 : /* Callback from inside blk_mq_rq_ctx_init(). */
845 0 : static void dd_prepare_request(struct request *rq)
846 : {
847 0 : rq->elv.priv[0] = NULL;
848 0 : }
849 :
850 : static bool dd_has_write_work(struct blk_mq_hw_ctx *hctx)
851 : {
852 : struct deadline_data *dd = hctx->queue->elevator->elevator_data;
853 : enum dd_prio p;
854 :
855 : for (p = 0; p <= DD_PRIO_MAX; p++)
856 : if (!list_empty_careful(&dd->per_prio[p].fifo_list[DD_WRITE]))
857 : return true;
858 :
859 : return false;
860 : }
861 :
862 : /*
863 : * Callback from inside blk_mq_free_request().
864 : *
865 : * For zoned block devices, write unlock the target zone of
866 : * completed write requests. Do this while holding the zone lock
867 : * spinlock so that the zone is never unlocked while deadline_fifo_request()
868 : * or deadline_next_request() are executing. This function is called for
869 : * all requests, whether or not these requests complete successfully.
870 : *
871 : * For a zoned block device, __dd_dispatch_request() may have stopped
872 : * dispatching requests if all the queued requests are write requests directed
873 : * at zones that are already locked due to on-going write requests. To ensure
874 : * write request dispatch progress in this case, mark the queue as needing a
875 : * restart to ensure that the queue is run again after completion of the
876 : * request and zones being unlocked.
877 : */
878 0 : static void dd_finish_request(struct request *rq)
879 : {
880 0 : struct request_queue *q = rq->q;
881 0 : struct deadline_data *dd = q->elevator->elevator_data;
882 0 : const u8 ioprio_class = dd_rq_ioclass(rq);
883 0 : const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
884 0 : struct dd_per_prio *per_prio = &dd->per_prio[prio];
885 :
886 : /*
887 : * The block layer core may call dd_finish_request() without having
888 : * called dd_insert_requests(). Skip requests that bypassed I/O
889 : * scheduling. See also blk_mq_request_bypass_insert().
890 : */
891 0 : if (!rq->elv.priv[0])
892 : return;
893 :
894 0 : atomic_inc(&per_prio->stats.completed);
895 :
896 0 : if (blk_queue_is_zoned(q)) {
897 : unsigned long flags;
898 :
899 : spin_lock_irqsave(&dd->zone_lock, flags);
900 : blk_req_zone_write_unlock(rq);
901 : spin_unlock_irqrestore(&dd->zone_lock, flags);
902 :
903 : if (dd_has_write_work(rq->mq_hctx))
904 : blk_mq_sched_mark_restart_hctx(rq->mq_hctx);
905 : }
906 : }
907 :
908 0 : static bool dd_has_work_for_prio(struct dd_per_prio *per_prio)
909 : {
910 0 : return !list_empty_careful(&per_prio->dispatch) ||
911 0 : !list_empty_careful(&per_prio->fifo_list[DD_READ]) ||
912 0 : !list_empty_careful(&per_prio->fifo_list[DD_WRITE]);
913 : }
914 :
915 0 : static bool dd_has_work(struct blk_mq_hw_ctx *hctx)
916 : {
917 0 : struct deadline_data *dd = hctx->queue->elevator->elevator_data;
918 : enum dd_prio prio;
919 :
920 0 : for (prio = 0; prio <= DD_PRIO_MAX; prio++)
921 0 : if (dd_has_work_for_prio(&dd->per_prio[prio]))
922 : return true;
923 :
924 : return false;
925 : }
926 :
927 : /*
928 : * sysfs parts below
929 : */
930 : #define SHOW_INT(__FUNC, __VAR) \
931 : static ssize_t __FUNC(struct elevator_queue *e, char *page) \
932 : { \
933 : struct deadline_data *dd = e->elevator_data; \
934 : \
935 : return sysfs_emit(page, "%d\n", __VAR); \
936 : }
937 : #define SHOW_JIFFIES(__FUNC, __VAR) SHOW_INT(__FUNC, jiffies_to_msecs(__VAR))
938 0 : SHOW_JIFFIES(deadline_read_expire_show, dd->fifo_expire[DD_READ]);
939 0 : SHOW_JIFFIES(deadline_write_expire_show, dd->fifo_expire[DD_WRITE]);
940 0 : SHOW_JIFFIES(deadline_prio_aging_expire_show, dd->prio_aging_expire);
941 0 : SHOW_INT(deadline_writes_starved_show, dd->writes_starved);
942 0 : SHOW_INT(deadline_front_merges_show, dd->front_merges);
943 0 : SHOW_INT(deadline_async_depth_show, dd->async_depth);
944 0 : SHOW_INT(deadline_fifo_batch_show, dd->fifo_batch);
945 : #undef SHOW_INT
946 : #undef SHOW_JIFFIES
947 :
948 : #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
949 : static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
950 : { \
951 : struct deadline_data *dd = e->elevator_data; \
952 : int __data, __ret; \
953 : \
954 : __ret = kstrtoint(page, 0, &__data); \
955 : if (__ret < 0) \
956 : return __ret; \
957 : if (__data < (MIN)) \
958 : __data = (MIN); \
959 : else if (__data > (MAX)) \
960 : __data = (MAX); \
961 : *(__PTR) = __CONV(__data); \
962 : return count; \
963 : }
964 : #define STORE_INT(__FUNC, __PTR, MIN, MAX) \
965 : STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, )
966 : #define STORE_JIFFIES(__FUNC, __PTR, MIN, MAX) \
967 : STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, msecs_to_jiffies)
968 0 : STORE_JIFFIES(deadline_read_expire_store, &dd->fifo_expire[DD_READ], 0, INT_MAX);
969 0 : STORE_JIFFIES(deadline_write_expire_store, &dd->fifo_expire[DD_WRITE], 0, INT_MAX);
970 0 : STORE_JIFFIES(deadline_prio_aging_expire_store, &dd->prio_aging_expire, 0, INT_MAX);
971 0 : STORE_INT(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX);
972 0 : STORE_INT(deadline_front_merges_store, &dd->front_merges, 0, 1);
973 0 : STORE_INT(deadline_async_depth_store, &dd->async_depth, 1, INT_MAX);
974 0 : STORE_INT(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX);
975 : #undef STORE_FUNCTION
976 : #undef STORE_INT
977 : #undef STORE_JIFFIES
978 :
979 : #define DD_ATTR(name) \
980 : __ATTR(name, 0644, deadline_##name##_show, deadline_##name##_store)
981 :
982 : static struct elv_fs_entry deadline_attrs[] = {
983 : DD_ATTR(read_expire),
984 : DD_ATTR(write_expire),
985 : DD_ATTR(writes_starved),
986 : DD_ATTR(front_merges),
987 : DD_ATTR(async_depth),
988 : DD_ATTR(fifo_batch),
989 : DD_ATTR(prio_aging_expire),
990 : __ATTR_NULL
991 : };
992 :
993 : #ifdef CONFIG_BLK_DEBUG_FS
994 : #define DEADLINE_DEBUGFS_DDIR_ATTRS(prio, data_dir, name) \
995 : static void *deadline_##name##_fifo_start(struct seq_file *m, \
996 : loff_t *pos) \
997 : __acquires(&dd->lock) \
998 : { \
999 : struct request_queue *q = m->private; \
1000 : struct deadline_data *dd = q->elevator->elevator_data; \
1001 : struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
1002 : \
1003 : spin_lock(&dd->lock); \
1004 : return seq_list_start(&per_prio->fifo_list[data_dir], *pos); \
1005 : } \
1006 : \
1007 : static void *deadline_##name##_fifo_next(struct seq_file *m, void *v, \
1008 : loff_t *pos) \
1009 : { \
1010 : struct request_queue *q = m->private; \
1011 : struct deadline_data *dd = q->elevator->elevator_data; \
1012 : struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
1013 : \
1014 : return seq_list_next(v, &per_prio->fifo_list[data_dir], pos); \
1015 : } \
1016 : \
1017 : static void deadline_##name##_fifo_stop(struct seq_file *m, void *v) \
1018 : __releases(&dd->lock) \
1019 : { \
1020 : struct request_queue *q = m->private; \
1021 : struct deadline_data *dd = q->elevator->elevator_data; \
1022 : \
1023 : spin_unlock(&dd->lock); \
1024 : } \
1025 : \
1026 : static const struct seq_operations deadline_##name##_fifo_seq_ops = { \
1027 : .start = deadline_##name##_fifo_start, \
1028 : .next = deadline_##name##_fifo_next, \
1029 : .stop = deadline_##name##_fifo_stop, \
1030 : .show = blk_mq_debugfs_rq_show, \
1031 : }; \
1032 : \
1033 : static int deadline_##name##_next_rq_show(void *data, \
1034 : struct seq_file *m) \
1035 : { \
1036 : struct request_queue *q = data; \
1037 : struct deadline_data *dd = q->elevator->elevator_data; \
1038 : struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
1039 : struct request *rq = per_prio->next_rq[data_dir]; \
1040 : \
1041 : if (rq) \
1042 : __blk_mq_debugfs_rq_show(m, rq); \
1043 : return 0; \
1044 : }
1045 :
1046 : DEADLINE_DEBUGFS_DDIR_ATTRS(DD_RT_PRIO, DD_READ, read0);
1047 : DEADLINE_DEBUGFS_DDIR_ATTRS(DD_RT_PRIO, DD_WRITE, write0);
1048 : DEADLINE_DEBUGFS_DDIR_ATTRS(DD_BE_PRIO, DD_READ, read1);
1049 : DEADLINE_DEBUGFS_DDIR_ATTRS(DD_BE_PRIO, DD_WRITE, write1);
1050 : DEADLINE_DEBUGFS_DDIR_ATTRS(DD_IDLE_PRIO, DD_READ, read2);
1051 : DEADLINE_DEBUGFS_DDIR_ATTRS(DD_IDLE_PRIO, DD_WRITE, write2);
1052 : #undef DEADLINE_DEBUGFS_DDIR_ATTRS
1053 :
1054 : static int deadline_batching_show(void *data, struct seq_file *m)
1055 : {
1056 : struct request_queue *q = data;
1057 : struct deadline_data *dd = q->elevator->elevator_data;
1058 :
1059 : seq_printf(m, "%u\n", dd->batching);
1060 : return 0;
1061 : }
1062 :
1063 : static int deadline_starved_show(void *data, struct seq_file *m)
1064 : {
1065 : struct request_queue *q = data;
1066 : struct deadline_data *dd = q->elevator->elevator_data;
1067 :
1068 : seq_printf(m, "%u\n", dd->starved);
1069 : return 0;
1070 : }
1071 :
1072 : static int dd_async_depth_show(void *data, struct seq_file *m)
1073 : {
1074 : struct request_queue *q = data;
1075 : struct deadline_data *dd = q->elevator->elevator_data;
1076 :
1077 : seq_printf(m, "%u\n", dd->async_depth);
1078 : return 0;
1079 : }
1080 :
1081 : static int dd_queued_show(void *data, struct seq_file *m)
1082 : {
1083 : struct request_queue *q = data;
1084 : struct deadline_data *dd = q->elevator->elevator_data;
1085 : u32 rt, be, idle;
1086 :
1087 : spin_lock(&dd->lock);
1088 : rt = dd_queued(dd, DD_RT_PRIO);
1089 : be = dd_queued(dd, DD_BE_PRIO);
1090 : idle = dd_queued(dd, DD_IDLE_PRIO);
1091 : spin_unlock(&dd->lock);
1092 :
1093 : seq_printf(m, "%u %u %u\n", rt, be, idle);
1094 :
1095 : return 0;
1096 : }
1097 :
1098 : /* Number of requests owned by the block driver for a given priority. */
1099 : static u32 dd_owned_by_driver(struct deadline_data *dd, enum dd_prio prio)
1100 : {
1101 : const struct io_stats_per_prio *stats = &dd->per_prio[prio].stats;
1102 :
1103 : lockdep_assert_held(&dd->lock);
1104 :
1105 : return stats->dispatched + stats->merged -
1106 : atomic_read(&stats->completed);
1107 : }
1108 :
1109 : static int dd_owned_by_driver_show(void *data, struct seq_file *m)
1110 : {
1111 : struct request_queue *q = data;
1112 : struct deadline_data *dd = q->elevator->elevator_data;
1113 : u32 rt, be, idle;
1114 :
1115 : spin_lock(&dd->lock);
1116 : rt = dd_owned_by_driver(dd, DD_RT_PRIO);
1117 : be = dd_owned_by_driver(dd, DD_BE_PRIO);
1118 : idle = dd_owned_by_driver(dd, DD_IDLE_PRIO);
1119 : spin_unlock(&dd->lock);
1120 :
1121 : seq_printf(m, "%u %u %u\n", rt, be, idle);
1122 :
1123 : return 0;
1124 : }
1125 :
1126 : #define DEADLINE_DISPATCH_ATTR(prio) \
1127 : static void *deadline_dispatch##prio##_start(struct seq_file *m, \
1128 : loff_t *pos) \
1129 : __acquires(&dd->lock) \
1130 : { \
1131 : struct request_queue *q = m->private; \
1132 : struct deadline_data *dd = q->elevator->elevator_data; \
1133 : struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
1134 : \
1135 : spin_lock(&dd->lock); \
1136 : return seq_list_start(&per_prio->dispatch, *pos); \
1137 : } \
1138 : \
1139 : static void *deadline_dispatch##prio##_next(struct seq_file *m, \
1140 : void *v, loff_t *pos) \
1141 : { \
1142 : struct request_queue *q = m->private; \
1143 : struct deadline_data *dd = q->elevator->elevator_data; \
1144 : struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
1145 : \
1146 : return seq_list_next(v, &per_prio->dispatch, pos); \
1147 : } \
1148 : \
1149 : static void deadline_dispatch##prio##_stop(struct seq_file *m, void *v) \
1150 : __releases(&dd->lock) \
1151 : { \
1152 : struct request_queue *q = m->private; \
1153 : struct deadline_data *dd = q->elevator->elevator_data; \
1154 : \
1155 : spin_unlock(&dd->lock); \
1156 : } \
1157 : \
1158 : static const struct seq_operations deadline_dispatch##prio##_seq_ops = { \
1159 : .start = deadline_dispatch##prio##_start, \
1160 : .next = deadline_dispatch##prio##_next, \
1161 : .stop = deadline_dispatch##prio##_stop, \
1162 : .show = blk_mq_debugfs_rq_show, \
1163 : }
1164 :
1165 : DEADLINE_DISPATCH_ATTR(0);
1166 : DEADLINE_DISPATCH_ATTR(1);
1167 : DEADLINE_DISPATCH_ATTR(2);
1168 : #undef DEADLINE_DISPATCH_ATTR
1169 :
1170 : #define DEADLINE_QUEUE_DDIR_ATTRS(name) \
1171 : {#name "_fifo_list", 0400, \
1172 : .seq_ops = &deadline_##name##_fifo_seq_ops}
1173 : #define DEADLINE_NEXT_RQ_ATTR(name) \
1174 : {#name "_next_rq", 0400, deadline_##name##_next_rq_show}
1175 : static const struct blk_mq_debugfs_attr deadline_queue_debugfs_attrs[] = {
1176 : DEADLINE_QUEUE_DDIR_ATTRS(read0),
1177 : DEADLINE_QUEUE_DDIR_ATTRS(write0),
1178 : DEADLINE_QUEUE_DDIR_ATTRS(read1),
1179 : DEADLINE_QUEUE_DDIR_ATTRS(write1),
1180 : DEADLINE_QUEUE_DDIR_ATTRS(read2),
1181 : DEADLINE_QUEUE_DDIR_ATTRS(write2),
1182 : DEADLINE_NEXT_RQ_ATTR(read0),
1183 : DEADLINE_NEXT_RQ_ATTR(write0),
1184 : DEADLINE_NEXT_RQ_ATTR(read1),
1185 : DEADLINE_NEXT_RQ_ATTR(write1),
1186 : DEADLINE_NEXT_RQ_ATTR(read2),
1187 : DEADLINE_NEXT_RQ_ATTR(write2),
1188 : {"batching", 0400, deadline_batching_show},
1189 : {"starved", 0400, deadline_starved_show},
1190 : {"async_depth", 0400, dd_async_depth_show},
1191 : {"dispatch0", 0400, .seq_ops = &deadline_dispatch0_seq_ops},
1192 : {"dispatch1", 0400, .seq_ops = &deadline_dispatch1_seq_ops},
1193 : {"dispatch2", 0400, .seq_ops = &deadline_dispatch2_seq_ops},
1194 : {"owned_by_driver", 0400, dd_owned_by_driver_show},
1195 : {"queued", 0400, dd_queued_show},
1196 : {},
1197 : };
1198 : #undef DEADLINE_QUEUE_DDIR_ATTRS
1199 : #endif
1200 :
1201 : static struct elevator_type mq_deadline = {
1202 : .ops = {
1203 : .depth_updated = dd_depth_updated,
1204 : .limit_depth = dd_limit_depth,
1205 : .insert_requests = dd_insert_requests,
1206 : .dispatch_request = dd_dispatch_request,
1207 : .prepare_request = dd_prepare_request,
1208 : .finish_request = dd_finish_request,
1209 : .next_request = elv_rb_latter_request,
1210 : .former_request = elv_rb_former_request,
1211 : .bio_merge = dd_bio_merge,
1212 : .request_merge = dd_request_merge,
1213 : .requests_merged = dd_merged_requests,
1214 : .request_merged = dd_request_merged,
1215 : .has_work = dd_has_work,
1216 : .init_sched = dd_init_sched,
1217 : .exit_sched = dd_exit_sched,
1218 : .init_hctx = dd_init_hctx,
1219 : },
1220 :
1221 : #ifdef CONFIG_BLK_DEBUG_FS
1222 : .queue_debugfs_attrs = deadline_queue_debugfs_attrs,
1223 : #endif
1224 : .elevator_attrs = deadline_attrs,
1225 : .elevator_name = "mq-deadline",
1226 : .elevator_alias = "deadline",
1227 : .elevator_features = ELEVATOR_F_ZBD_SEQ_WRITE,
1228 : .elevator_owner = THIS_MODULE,
1229 : };
1230 : MODULE_ALIAS("mq-deadline-iosched");
1231 :
1232 1 : static int __init deadline_init(void)
1233 : {
1234 1 : return elv_register(&mq_deadline);
1235 : }
1236 :
1237 0 : static void __exit deadline_exit(void)
1238 : {
1239 0 : elv_unregister(&mq_deadline);
1240 0 : }
1241 :
1242 : module_init(deadline_init);
1243 : module_exit(deadline_exit);
1244 :
1245 : MODULE_AUTHOR("Jens Axboe, Damien Le Moal and Bart Van Assche");
1246 : MODULE_LICENSE("GPL");
1247 : MODULE_DESCRIPTION("MQ deadline IO scheduler");
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