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