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9#include <linux/kernel.h>
10#include <linux/blkdev.h>
11#include <linux/blk-mq.h>
12#include <linux/module.h>
13#include <linux/sbitmap.h>
14
15#include <trace/events/block.h>
16
17#include "elevator.h"
18#include "blk.h"
19#include "blk-mq.h"
20#include "blk-mq-debugfs.h"
21#include "blk-mq-sched.h"
22#include "blk-mq-tag.h"
23
24#define CREATE_TRACE_POINTS
25#include <trace/events/kyber.h>
26
27
28
29
30
31enum {
32 KYBER_READ,
33 KYBER_WRITE,
34 KYBER_DISCARD,
35 KYBER_OTHER,
36 KYBER_NUM_DOMAINS,
37};
38
39static const char *kyber_domain_names[] = {
40 [KYBER_READ] = "READ",
41 [KYBER_WRITE] = "WRITE",
42 [KYBER_DISCARD] = "DISCARD",
43 [KYBER_OTHER] = "OTHER",
44};
45
46enum {
47
48
49
50
51
52 KYBER_ASYNC_PERCENT = 75,
53};
54
55
56
57
58
59
60
61
62static const unsigned int kyber_depth[] = {
63 [KYBER_READ] = 256,
64 [KYBER_WRITE] = 128,
65 [KYBER_DISCARD] = 64,
66 [KYBER_OTHER] = 16,
67};
68
69
70
71
72static const u64 kyber_latency_targets[] = {
73 [KYBER_READ] = 2ULL * NSEC_PER_MSEC,
74 [KYBER_WRITE] = 10ULL * NSEC_PER_MSEC,
75 [KYBER_DISCARD] = 5ULL * NSEC_PER_SEC,
76};
77
78
79
80
81
82static const unsigned int kyber_batch_size[] = {
83 [KYBER_READ] = 16,
84 [KYBER_WRITE] = 8,
85 [KYBER_DISCARD] = 1,
86 [KYBER_OTHER] = 1,
87};
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102enum {
103
104
105
106
107 KYBER_LATENCY_SHIFT = 2,
108
109
110
111
112 KYBER_GOOD_BUCKETS = 1 << KYBER_LATENCY_SHIFT,
113
114 KYBER_LATENCY_BUCKETS = 2 << KYBER_LATENCY_SHIFT,
115};
116
117
118
119
120
121enum {
122 KYBER_TOTAL_LATENCY,
123 KYBER_IO_LATENCY,
124};
125
126static const char *kyber_latency_type_names[] = {
127 [KYBER_TOTAL_LATENCY] = "total",
128 [KYBER_IO_LATENCY] = "I/O",
129};
130
131
132
133
134
135struct kyber_cpu_latency {
136 atomic_t buckets[KYBER_OTHER][2][KYBER_LATENCY_BUCKETS];
137};
138
139
140
141
142
143struct kyber_ctx_queue {
144
145
146
147
148 spinlock_t lock;
149 struct list_head rq_list[KYBER_NUM_DOMAINS];
150} ____cacheline_aligned_in_smp;
151
152struct kyber_queue_data {
153 struct request_queue *q;
154 dev_t dev;
155
156
157
158
159
160 struct sbitmap_queue domain_tokens[KYBER_NUM_DOMAINS];
161
162
163
164
165
166 unsigned int async_depth;
167
168 struct kyber_cpu_latency __percpu *cpu_latency;
169
170
171 struct timer_list timer;
172
173 unsigned int latency_buckets[KYBER_OTHER][2][KYBER_LATENCY_BUCKETS];
174
175 unsigned long latency_timeout[KYBER_OTHER];
176
177 int domain_p99[KYBER_OTHER];
178
179
180 u64 latency_targets[KYBER_OTHER];
181};
182
183struct kyber_hctx_data {
184 spinlock_t lock;
185 struct list_head rqs[KYBER_NUM_DOMAINS];
186 unsigned int cur_domain;
187 unsigned int batching;
188 struct kyber_ctx_queue *kcqs;
189 struct sbitmap kcq_map[KYBER_NUM_DOMAINS];
190 struct sbq_wait domain_wait[KYBER_NUM_DOMAINS];
191 struct sbq_wait_state *domain_ws[KYBER_NUM_DOMAINS];
192 atomic_t wait_index[KYBER_NUM_DOMAINS];
193};
194
195static int kyber_domain_wake(wait_queue_entry_t *wait, unsigned mode, int flags,
196 void *key);
197
198static unsigned int kyber_sched_domain(unsigned int op)
199{
200 switch (op & REQ_OP_MASK) {
201 case REQ_OP_READ:
202 return KYBER_READ;
203 case REQ_OP_WRITE:
204 return KYBER_WRITE;
205 case REQ_OP_DISCARD:
206 return KYBER_DISCARD;
207 default:
208 return KYBER_OTHER;
209 }
210}
211
212static void flush_latency_buckets(struct kyber_queue_data *kqd,
213 struct kyber_cpu_latency *cpu_latency,
214 unsigned int sched_domain, unsigned int type)
215{
216 unsigned int *buckets = kqd->latency_buckets[sched_domain][type];
217 atomic_t *cpu_buckets = cpu_latency->buckets[sched_domain][type];
218 unsigned int bucket;
219
220 for (bucket = 0; bucket < KYBER_LATENCY_BUCKETS; bucket++)
221 buckets[bucket] += atomic_xchg(&cpu_buckets[bucket], 0);
222}
223
224
225
226
227
228static int calculate_percentile(struct kyber_queue_data *kqd,
229 unsigned int sched_domain, unsigned int type,
230 unsigned int percentile)
231{
232 unsigned int *buckets = kqd->latency_buckets[sched_domain][type];
233 unsigned int bucket, samples = 0, percentile_samples;
234
235 for (bucket = 0; bucket < KYBER_LATENCY_BUCKETS; bucket++)
236 samples += buckets[bucket];
237
238 if (!samples)
239 return -1;
240
241
242
243
244
245 if (!kqd->latency_timeout[sched_domain])
246 kqd->latency_timeout[sched_domain] = max(jiffies + HZ, 1UL);
247 if (samples < 500 &&
248 time_is_after_jiffies(kqd->latency_timeout[sched_domain])) {
249 return -1;
250 }
251 kqd->latency_timeout[sched_domain] = 0;
252
253 percentile_samples = DIV_ROUND_UP(samples * percentile, 100);
254 for (bucket = 0; bucket < KYBER_LATENCY_BUCKETS - 1; bucket++) {
255 if (buckets[bucket] >= percentile_samples)
256 break;
257 percentile_samples -= buckets[bucket];
258 }
259 memset(buckets, 0, sizeof(kqd->latency_buckets[sched_domain][type]));
260
261 trace_kyber_latency(kqd->dev, kyber_domain_names[sched_domain],
262 kyber_latency_type_names[type], percentile,
263 bucket + 1, 1 << KYBER_LATENCY_SHIFT, samples);
264
265 return bucket;
266}
267
268static void kyber_resize_domain(struct kyber_queue_data *kqd,
269 unsigned int sched_domain, unsigned int depth)
270{
271 depth = clamp(depth, 1U, kyber_depth[sched_domain]);
272 if (depth != kqd->domain_tokens[sched_domain].sb.depth) {
273 sbitmap_queue_resize(&kqd->domain_tokens[sched_domain], depth);
274 trace_kyber_adjust(kqd->dev, kyber_domain_names[sched_domain],
275 depth);
276 }
277}
278
279static void kyber_timer_fn(struct timer_list *t)
280{
281 struct kyber_queue_data *kqd = from_timer(kqd, t, timer);
282 unsigned int sched_domain;
283 int cpu;
284 bool bad = false;
285
286
287 for_each_online_cpu(cpu) {
288 struct kyber_cpu_latency *cpu_latency;
289
290 cpu_latency = per_cpu_ptr(kqd->cpu_latency, cpu);
291 for (sched_domain = 0; sched_domain < KYBER_OTHER; sched_domain++) {
292 flush_latency_buckets(kqd, cpu_latency, sched_domain,
293 KYBER_TOTAL_LATENCY);
294 flush_latency_buckets(kqd, cpu_latency, sched_domain,
295 KYBER_IO_LATENCY);
296 }
297 }
298
299
300
301
302
303
304 for (sched_domain = 0; sched_domain < KYBER_OTHER; sched_domain++) {
305 int p90;
306
307 p90 = calculate_percentile(kqd, sched_domain, KYBER_IO_LATENCY,
308 90);
309 if (p90 >= KYBER_GOOD_BUCKETS)
310 bad = true;
311 }
312
313
314
315
316
317
318 for (sched_domain = 0; sched_domain < KYBER_OTHER; sched_domain++) {
319 unsigned int orig_depth, depth;
320 int p99;
321
322 p99 = calculate_percentile(kqd, sched_domain,
323 KYBER_TOTAL_LATENCY, 99);
324
325
326
327
328
329
330
331
332 if (bad) {
333 if (p99 < 0)
334 p99 = kqd->domain_p99[sched_domain];
335 kqd->domain_p99[sched_domain] = -1;
336 } else if (p99 >= 0) {
337 kqd->domain_p99[sched_domain] = p99;
338 }
339 if (p99 < 0)
340 continue;
341
342
343
344
345
346
347
348
349
350
351 if (bad || p99 >= KYBER_GOOD_BUCKETS) {
352 orig_depth = kqd->domain_tokens[sched_domain].sb.depth;
353 depth = (orig_depth * (p99 + 1)) >> KYBER_LATENCY_SHIFT;
354 kyber_resize_domain(kqd, sched_domain, depth);
355 }
356 }
357}
358
359static struct kyber_queue_data *kyber_queue_data_alloc(struct request_queue *q)
360{
361 struct kyber_queue_data *kqd;
362 int ret = -ENOMEM;
363 int i;
364
365 kqd = kzalloc_node(sizeof(*kqd), GFP_KERNEL, q->node);
366 if (!kqd)
367 goto err;
368
369 kqd->q = q;
370 kqd->dev = disk_devt(q->disk);
371
372 kqd->cpu_latency = alloc_percpu_gfp(struct kyber_cpu_latency,
373 GFP_KERNEL | __GFP_ZERO);
374 if (!kqd->cpu_latency)
375 goto err_kqd;
376
377 timer_setup(&kqd->timer, kyber_timer_fn, 0);
378
379 for (i = 0; i < KYBER_NUM_DOMAINS; i++) {
380 WARN_ON(!kyber_depth[i]);
381 WARN_ON(!kyber_batch_size[i]);
382 ret = sbitmap_queue_init_node(&kqd->domain_tokens[i],
383 kyber_depth[i], -1, false,
384 GFP_KERNEL, q->node);
385 if (ret) {
386 while (--i >= 0)
387 sbitmap_queue_free(&kqd->domain_tokens[i]);
388 goto err_buckets;
389 }
390 }
391
392 for (i = 0; i < KYBER_OTHER; i++) {
393 kqd->domain_p99[i] = -1;
394 kqd->latency_targets[i] = kyber_latency_targets[i];
395 }
396
397 return kqd;
398
399err_buckets:
400 free_percpu(kqd->cpu_latency);
401err_kqd:
402 kfree(kqd);
403err:
404 return ERR_PTR(ret);
405}
406
407static int kyber_init_sched(struct request_queue *q, struct elevator_type *e)
408{
409 struct kyber_queue_data *kqd;
410 struct elevator_queue *eq;
411
412 eq = elevator_alloc(q, e);
413 if (!eq)
414 return -ENOMEM;
415
416 kqd = kyber_queue_data_alloc(q);
417 if (IS_ERR(kqd)) {
418 kobject_put(&eq->kobj);
419 return PTR_ERR(kqd);
420 }
421
422 blk_stat_enable_accounting(q);
423
424 eq->elevator_data = kqd;
425 q->elevator = eq;
426
427 return 0;
428}
429
430static void kyber_exit_sched(struct elevator_queue *e)
431{
432 struct kyber_queue_data *kqd = e->elevator_data;
433 int i;
434
435 del_timer_sync(&kqd->timer);
436 blk_stat_disable_accounting(kqd->q);
437
438 for (i = 0; i < KYBER_NUM_DOMAINS; i++)
439 sbitmap_queue_free(&kqd->domain_tokens[i]);
440 free_percpu(kqd->cpu_latency);
441 kfree(kqd);
442}
443
444static void kyber_ctx_queue_init(struct kyber_ctx_queue *kcq)
445{
446 unsigned int i;
447
448 spin_lock_init(&kcq->lock);
449 for (i = 0; i < KYBER_NUM_DOMAINS; i++)
450 INIT_LIST_HEAD(&kcq->rq_list[i]);
451}
452
453static void kyber_depth_updated(struct blk_mq_hw_ctx *hctx)
454{
455 struct kyber_queue_data *kqd = hctx->queue->elevator->elevator_data;
456 struct blk_mq_tags *tags = hctx->sched_tags;
457 unsigned int shift = tags->bitmap_tags.sb.shift;
458
459 kqd->async_depth = (1U << shift) * KYBER_ASYNC_PERCENT / 100U;
460
461 sbitmap_queue_min_shallow_depth(&tags->bitmap_tags, kqd->async_depth);
462}
463
464static int kyber_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
465{
466 struct kyber_hctx_data *khd;
467 int i;
468
469 khd = kmalloc_node(sizeof(*khd), GFP_KERNEL, hctx->numa_node);
470 if (!khd)
471 return -ENOMEM;
472
473 khd->kcqs = kmalloc_array_node(hctx->nr_ctx,
474 sizeof(struct kyber_ctx_queue),
475 GFP_KERNEL, hctx->numa_node);
476 if (!khd->kcqs)
477 goto err_khd;
478
479 for (i = 0; i < hctx->nr_ctx; i++)
480 kyber_ctx_queue_init(&khd->kcqs[i]);
481
482 for (i = 0; i < KYBER_NUM_DOMAINS; i++) {
483 if (sbitmap_init_node(&khd->kcq_map[i], hctx->nr_ctx,
484 ilog2(8), GFP_KERNEL, hctx->numa_node,
485 false, false)) {
486 while (--i >= 0)
487 sbitmap_free(&khd->kcq_map[i]);
488 goto err_kcqs;
489 }
490 }
491
492 spin_lock_init(&khd->lock);
493
494 for (i = 0; i < KYBER_NUM_DOMAINS; i++) {
495 INIT_LIST_HEAD(&khd->rqs[i]);
496 khd->domain_wait[i].sbq = NULL;
497 init_waitqueue_func_entry(&khd->domain_wait[i].wait,
498 kyber_domain_wake);
499 khd->domain_wait[i].wait.private = hctx;
500 INIT_LIST_HEAD(&khd->domain_wait[i].wait.entry);
501 atomic_set(&khd->wait_index[i], 0);
502 }
503
504 khd->cur_domain = 0;
505 khd->batching = 0;
506
507 hctx->sched_data = khd;
508 kyber_depth_updated(hctx);
509
510 return 0;
511
512err_kcqs:
513 kfree(khd->kcqs);
514err_khd:
515 kfree(khd);
516 return -ENOMEM;
517}
518
519static void kyber_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
520{
521 struct kyber_hctx_data *khd = hctx->sched_data;
522 int i;
523
524 for (i = 0; i < KYBER_NUM_DOMAINS; i++)
525 sbitmap_free(&khd->kcq_map[i]);
526 kfree(khd->kcqs);
527 kfree(hctx->sched_data);
528}
529
530static int rq_get_domain_token(struct request *rq)
531{
532 return (long)rq->elv.priv[0];
533}
534
535static void rq_set_domain_token(struct request *rq, int token)
536{
537 rq->elv.priv[0] = (void *)(long)token;
538}
539
540static void rq_clear_domain_token(struct kyber_queue_data *kqd,
541 struct request *rq)
542{
543 unsigned int sched_domain;
544 int nr;
545
546 nr = rq_get_domain_token(rq);
547 if (nr != -1) {
548 sched_domain = kyber_sched_domain(rq->cmd_flags);
549 sbitmap_queue_clear(&kqd->domain_tokens[sched_domain], nr,
550 rq->mq_ctx->cpu);
551 }
552}
553
554static void kyber_limit_depth(unsigned int op, struct blk_mq_alloc_data *data)
555{
556
557
558
559
560 if (!op_is_sync(op)) {
561 struct kyber_queue_data *kqd = data->q->elevator->elevator_data;
562
563 data->shallow_depth = kqd->async_depth;
564 }
565}
566
567static bool kyber_bio_merge(struct request_queue *q, struct bio *bio,
568 unsigned int nr_segs)
569{
570 struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
571 struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, bio->bi_opf, ctx);
572 struct kyber_hctx_data *khd = hctx->sched_data;
573 struct kyber_ctx_queue *kcq = &khd->kcqs[ctx->index_hw[hctx->type]];
574 unsigned int sched_domain = kyber_sched_domain(bio->bi_opf);
575 struct list_head *rq_list = &kcq->rq_list[sched_domain];
576 bool merged;
577
578 spin_lock(&kcq->lock);
579 merged = blk_bio_list_merge(hctx->queue, rq_list, bio, nr_segs);
580 spin_unlock(&kcq->lock);
581
582 return merged;
583}
584
585static void kyber_prepare_request(struct request *rq)
586{
587 rq_set_domain_token(rq, -1);
588}
589
590static void kyber_insert_requests(struct blk_mq_hw_ctx *hctx,
591 struct list_head *rq_list, bool at_head)
592{
593 struct kyber_hctx_data *khd = hctx->sched_data;
594 struct request *rq, *next;
595
596 list_for_each_entry_safe(rq, next, rq_list, queuelist) {
597 unsigned int sched_domain = kyber_sched_domain(rq->cmd_flags);
598 struct kyber_ctx_queue *kcq = &khd->kcqs[rq->mq_ctx->index_hw[hctx->type]];
599 struct list_head *head = &kcq->rq_list[sched_domain];
600
601 spin_lock(&kcq->lock);
602 trace_block_rq_insert(rq);
603 if (at_head)
604 list_move(&rq->queuelist, head);
605 else
606 list_move_tail(&rq->queuelist, head);
607 sbitmap_set_bit(&khd->kcq_map[sched_domain],
608 rq->mq_ctx->index_hw[hctx->type]);
609 spin_unlock(&kcq->lock);
610 }
611}
612
613static void kyber_finish_request(struct request *rq)
614{
615 struct kyber_queue_data *kqd = rq->q->elevator->elevator_data;
616
617 rq_clear_domain_token(kqd, rq);
618}
619
620static void add_latency_sample(struct kyber_cpu_latency *cpu_latency,
621 unsigned int sched_domain, unsigned int type,
622 u64 target, u64 latency)
623{
624 unsigned int bucket;
625 u64 divisor;
626
627 if (latency > 0) {
628 divisor = max_t(u64, target >> KYBER_LATENCY_SHIFT, 1);
629 bucket = min_t(unsigned int, div64_u64(latency - 1, divisor),
630 KYBER_LATENCY_BUCKETS - 1);
631 } else {
632 bucket = 0;
633 }
634
635 atomic_inc(&cpu_latency->buckets[sched_domain][type][bucket]);
636}
637
638static void kyber_completed_request(struct request *rq, u64 now)
639{
640 struct kyber_queue_data *kqd = rq->q->elevator->elevator_data;
641 struct kyber_cpu_latency *cpu_latency;
642 unsigned int sched_domain;
643 u64 target;
644
645 sched_domain = kyber_sched_domain(rq->cmd_flags);
646 if (sched_domain == KYBER_OTHER)
647 return;
648
649 cpu_latency = get_cpu_ptr(kqd->cpu_latency);
650 target = kqd->latency_targets[sched_domain];
651 add_latency_sample(cpu_latency, sched_domain, KYBER_TOTAL_LATENCY,
652 target, now - rq->start_time_ns);
653 add_latency_sample(cpu_latency, sched_domain, KYBER_IO_LATENCY, target,
654 now - rq->io_start_time_ns);
655 put_cpu_ptr(kqd->cpu_latency);
656
657 timer_reduce(&kqd->timer, jiffies + HZ / 10);
658}
659
660struct flush_kcq_data {
661 struct kyber_hctx_data *khd;
662 unsigned int sched_domain;
663 struct list_head *list;
664};
665
666static bool flush_busy_kcq(struct sbitmap *sb, unsigned int bitnr, void *data)
667{
668 struct flush_kcq_data *flush_data = data;
669 struct kyber_ctx_queue *kcq = &flush_data->khd->kcqs[bitnr];
670
671 spin_lock(&kcq->lock);
672 list_splice_tail_init(&kcq->rq_list[flush_data->sched_domain],
673 flush_data->list);
674 sbitmap_clear_bit(sb, bitnr);
675 spin_unlock(&kcq->lock);
676
677 return true;
678}
679
680static void kyber_flush_busy_kcqs(struct kyber_hctx_data *khd,
681 unsigned int sched_domain,
682 struct list_head *list)
683{
684 struct flush_kcq_data data = {
685 .khd = khd,
686 .sched_domain = sched_domain,
687 .list = list,
688 };
689
690 sbitmap_for_each_set(&khd->kcq_map[sched_domain],
691 flush_busy_kcq, &data);
692}
693
694static int kyber_domain_wake(wait_queue_entry_t *wqe, unsigned mode, int flags,
695 void *key)
696{
697 struct blk_mq_hw_ctx *hctx = READ_ONCE(wqe->private);
698 struct sbq_wait *wait = container_of(wqe, struct sbq_wait, wait);
699
700 sbitmap_del_wait_queue(wait);
701 blk_mq_run_hw_queue(hctx, true);
702 return 1;
703}
704
705static int kyber_get_domain_token(struct kyber_queue_data *kqd,
706 struct kyber_hctx_data *khd,
707 struct blk_mq_hw_ctx *hctx)
708{
709 unsigned int sched_domain = khd->cur_domain;
710 struct sbitmap_queue *domain_tokens = &kqd->domain_tokens[sched_domain];
711 struct sbq_wait *wait = &khd->domain_wait[sched_domain];
712 struct sbq_wait_state *ws;
713 int nr;
714
715 nr = __sbitmap_queue_get(domain_tokens);
716
717
718
719
720
721
722 if (nr < 0 && list_empty_careful(&wait->wait.entry)) {
723 ws = sbq_wait_ptr(domain_tokens,
724 &khd->wait_index[sched_domain]);
725 khd->domain_ws[sched_domain] = ws;
726 sbitmap_add_wait_queue(domain_tokens, ws, wait);
727
728
729
730
731
732 nr = __sbitmap_queue_get(domain_tokens);
733 }
734
735
736
737
738
739
740
741
742 if (nr >= 0 && !list_empty_careful(&wait->wait.entry)) {
743 ws = khd->domain_ws[sched_domain];
744 spin_lock_irq(&ws->wait.lock);
745 sbitmap_del_wait_queue(wait);
746 spin_unlock_irq(&ws->wait.lock);
747 }
748
749 return nr;
750}
751
752static struct request *
753kyber_dispatch_cur_domain(struct kyber_queue_data *kqd,
754 struct kyber_hctx_data *khd,
755 struct blk_mq_hw_ctx *hctx)
756{
757 struct list_head *rqs;
758 struct request *rq;
759 int nr;
760
761 rqs = &khd->rqs[khd->cur_domain];
762
763
764
765
766
767
768
769
770
771 rq = list_first_entry_or_null(rqs, struct request, queuelist);
772 if (rq) {
773 nr = kyber_get_domain_token(kqd, khd, hctx);
774 if (nr >= 0) {
775 khd->batching++;
776 rq_set_domain_token(rq, nr);
777 list_del_init(&rq->queuelist);
778 return rq;
779 } else {
780 trace_kyber_throttled(kqd->dev,
781 kyber_domain_names[khd->cur_domain]);
782 }
783 } else if (sbitmap_any_bit_set(&khd->kcq_map[khd->cur_domain])) {
784 nr = kyber_get_domain_token(kqd, khd, hctx);
785 if (nr >= 0) {
786 kyber_flush_busy_kcqs(khd, khd->cur_domain, rqs);
787 rq = list_first_entry(rqs, struct request, queuelist);
788 khd->batching++;
789 rq_set_domain_token(rq, nr);
790 list_del_init(&rq->queuelist);
791 return rq;
792 } else {
793 trace_kyber_throttled(kqd->dev,
794 kyber_domain_names[khd->cur_domain]);
795 }
796 }
797
798
799 return NULL;
800}
801
802static struct request *kyber_dispatch_request(struct blk_mq_hw_ctx *hctx)
803{
804 struct kyber_queue_data *kqd = hctx->queue->elevator->elevator_data;
805 struct kyber_hctx_data *khd = hctx->sched_data;
806 struct request *rq;
807 int i;
808
809 spin_lock(&khd->lock);
810
811
812
813
814
815 if (khd->batching < kyber_batch_size[khd->cur_domain]) {
816 rq = kyber_dispatch_cur_domain(kqd, khd, hctx);
817 if (rq)
818 goto out;
819 }
820
821
822
823
824
825
826
827
828
829
830 khd->batching = 0;
831 for (i = 0; i < KYBER_NUM_DOMAINS; i++) {
832 if (khd->cur_domain == KYBER_NUM_DOMAINS - 1)
833 khd->cur_domain = 0;
834 else
835 khd->cur_domain++;
836
837 rq = kyber_dispatch_cur_domain(kqd, khd, hctx);
838 if (rq)
839 goto out;
840 }
841
842 rq = NULL;
843out:
844 spin_unlock(&khd->lock);
845 return rq;
846}
847
848static bool kyber_has_work(struct blk_mq_hw_ctx *hctx)
849{
850 struct kyber_hctx_data *khd = hctx->sched_data;
851 int i;
852
853 for (i = 0; i < KYBER_NUM_DOMAINS; i++) {
854 if (!list_empty_careful(&khd->rqs[i]) ||
855 sbitmap_any_bit_set(&khd->kcq_map[i]))
856 return true;
857 }
858
859 return false;
860}
861
862#define KYBER_LAT_SHOW_STORE(domain, name) \
863static ssize_t kyber_##name##_lat_show(struct elevator_queue *e, \
864 char *page) \
865{ \
866 struct kyber_queue_data *kqd = e->elevator_data; \
867 \
868 return sprintf(page, "%llu\n", kqd->latency_targets[domain]); \
869} \
870 \
871static ssize_t kyber_##name##_lat_store(struct elevator_queue *e, \
872 const char *page, size_t count) \
873{ \
874 struct kyber_queue_data *kqd = e->elevator_data; \
875 unsigned long long nsec; \
876 int ret; \
877 \
878 ret = kstrtoull(page, 10, &nsec); \
879 if (ret) \
880 return ret; \
881 \
882 kqd->latency_targets[domain] = nsec; \
883 \
884 return count; \
885}
886KYBER_LAT_SHOW_STORE(KYBER_READ, read);
887KYBER_LAT_SHOW_STORE(KYBER_WRITE, write);
888#undef KYBER_LAT_SHOW_STORE
889
890#define KYBER_LAT_ATTR(op) __ATTR(op##_lat_nsec, 0644, kyber_##op##_lat_show, kyber_##op##_lat_store)
891static struct elv_fs_entry kyber_sched_attrs[] = {
892 KYBER_LAT_ATTR(read),
893 KYBER_LAT_ATTR(write),
894 __ATTR_NULL
895};
896#undef KYBER_LAT_ATTR
897
898#ifdef CONFIG_BLK_DEBUG_FS
899#define KYBER_DEBUGFS_DOMAIN_ATTRS(domain, name) \
900static int kyber_##name##_tokens_show(void *data, struct seq_file *m) \
901{ \
902 struct request_queue *q = data; \
903 struct kyber_queue_data *kqd = q->elevator->elevator_data; \
904 \
905 sbitmap_queue_show(&kqd->domain_tokens[domain], m); \
906 return 0; \
907} \
908 \
909static void *kyber_##name##_rqs_start(struct seq_file *m, loff_t *pos) \
910 __acquires(&khd->lock) \
911{ \
912 struct blk_mq_hw_ctx *hctx = m->private; \
913 struct kyber_hctx_data *khd = hctx->sched_data; \
914 \
915 spin_lock(&khd->lock); \
916 return seq_list_start(&khd->rqs[domain], *pos); \
917} \
918 \
919static void *kyber_##name##_rqs_next(struct seq_file *m, void *v, \
920 loff_t *pos) \
921{ \
922 struct blk_mq_hw_ctx *hctx = m->private; \
923 struct kyber_hctx_data *khd = hctx->sched_data; \
924 \
925 return seq_list_next(v, &khd->rqs[domain], pos); \
926} \
927 \
928static void kyber_##name##_rqs_stop(struct seq_file *m, void *v) \
929 __releases(&khd->lock) \
930{ \
931 struct blk_mq_hw_ctx *hctx = m->private; \
932 struct kyber_hctx_data *khd = hctx->sched_data; \
933 \
934 spin_unlock(&khd->lock); \
935} \
936 \
937static const struct seq_operations kyber_##name##_rqs_seq_ops = { \
938 .start = kyber_##name##_rqs_start, \
939 .next = kyber_##name##_rqs_next, \
940 .stop = kyber_##name##_rqs_stop, \
941 .show = blk_mq_debugfs_rq_show, \
942}; \
943 \
944static int kyber_##name##_waiting_show(void *data, struct seq_file *m) \
945{ \
946 struct blk_mq_hw_ctx *hctx = data; \
947 struct kyber_hctx_data *khd = hctx->sched_data; \
948 wait_queue_entry_t *wait = &khd->domain_wait[domain].wait; \
949 \
950 seq_printf(m, "%d\n", !list_empty_careful(&wait->entry)); \
951 return 0; \
952}
953KYBER_DEBUGFS_DOMAIN_ATTRS(KYBER_READ, read)
954KYBER_DEBUGFS_DOMAIN_ATTRS(KYBER_WRITE, write)
955KYBER_DEBUGFS_DOMAIN_ATTRS(KYBER_DISCARD, discard)
956KYBER_DEBUGFS_DOMAIN_ATTRS(KYBER_OTHER, other)
957#undef KYBER_DEBUGFS_DOMAIN_ATTRS
958
959static int kyber_async_depth_show(void *data, struct seq_file *m)
960{
961 struct request_queue *q = data;
962 struct kyber_queue_data *kqd = q->elevator->elevator_data;
963
964 seq_printf(m, "%u\n", kqd->async_depth);
965 return 0;
966}
967
968static int kyber_cur_domain_show(void *data, struct seq_file *m)
969{
970 struct blk_mq_hw_ctx *hctx = data;
971 struct kyber_hctx_data *khd = hctx->sched_data;
972
973 seq_printf(m, "%s\n", kyber_domain_names[khd->cur_domain]);
974 return 0;
975}
976
977static int kyber_batching_show(void *data, struct seq_file *m)
978{
979 struct blk_mq_hw_ctx *hctx = data;
980 struct kyber_hctx_data *khd = hctx->sched_data;
981
982 seq_printf(m, "%u\n", khd->batching);
983 return 0;
984}
985
986#define KYBER_QUEUE_DOMAIN_ATTRS(name) \
987 {#name "_tokens", 0400, kyber_##name##_tokens_show}
988static const struct blk_mq_debugfs_attr kyber_queue_debugfs_attrs[] = {
989 KYBER_QUEUE_DOMAIN_ATTRS(read),
990 KYBER_QUEUE_DOMAIN_ATTRS(write),
991 KYBER_QUEUE_DOMAIN_ATTRS(discard),
992 KYBER_QUEUE_DOMAIN_ATTRS(other),
993 {"async_depth", 0400, kyber_async_depth_show},
994 {},
995};
996#undef KYBER_QUEUE_DOMAIN_ATTRS
997
998#define KYBER_HCTX_DOMAIN_ATTRS(name) \
999 {#name "_rqs", 0400, .seq_ops = &kyber_##name##_rqs_seq_ops}, \
1000 {#name "_waiting", 0400, kyber_##name##_waiting_show}
1001static const struct blk_mq_debugfs_attr kyber_hctx_debugfs_attrs[] = {
1002 KYBER_HCTX_DOMAIN_ATTRS(read),
1003 KYBER_HCTX_DOMAIN_ATTRS(write),
1004 KYBER_HCTX_DOMAIN_ATTRS(discard),
1005 KYBER_HCTX_DOMAIN_ATTRS(other),
1006 {"cur_domain", 0400, kyber_cur_domain_show},
1007 {"batching", 0400, kyber_batching_show},
1008 {},
1009};
1010#undef KYBER_HCTX_DOMAIN_ATTRS
1011#endif
1012
1013static struct elevator_type kyber_sched = {
1014 .ops = {
1015 .init_sched = kyber_init_sched,
1016 .exit_sched = kyber_exit_sched,
1017 .init_hctx = kyber_init_hctx,
1018 .exit_hctx = kyber_exit_hctx,
1019 .limit_depth = kyber_limit_depth,
1020 .bio_merge = kyber_bio_merge,
1021 .prepare_request = kyber_prepare_request,
1022 .insert_requests = kyber_insert_requests,
1023 .finish_request = kyber_finish_request,
1024 .requeue_request = kyber_finish_request,
1025 .completed_request = kyber_completed_request,
1026 .dispatch_request = kyber_dispatch_request,
1027 .has_work = kyber_has_work,
1028 .depth_updated = kyber_depth_updated,
1029 },
1030#ifdef CONFIG_BLK_DEBUG_FS
1031 .queue_debugfs_attrs = kyber_queue_debugfs_attrs,
1032 .hctx_debugfs_attrs = kyber_hctx_debugfs_attrs,
1033#endif
1034 .elevator_attrs = kyber_sched_attrs,
1035 .elevator_name = "kyber",
1036 .elevator_features = ELEVATOR_F_MQ_AWARE,
1037 .elevator_owner = THIS_MODULE,
1038};
1039
1040static int __init kyber_init(void)
1041{
1042 return elv_register(&kyber_sched);
1043}
1044
1045static void __exit kyber_exit(void)
1046{
1047 elv_unregister(&kyber_sched);
1048}
1049
1050module_init(kyber_init);
1051module_exit(kyber_exit);
1052
1053MODULE_AUTHOR("Omar Sandoval");
1054MODULE_LICENSE("GPL");
1055MODULE_DESCRIPTION("Kyber I/O scheduler");
1056