x86/mm/pat: Don't report PAT on CPUs that don't support it
[linux/fpc-iii.git] / block / blk-mq-sched.c
blobc974a1bbf4cbad70ccea464e94d2788c62078dde
1 /*
2 * blk-mq scheduling framework
4 * Copyright (C) 2016 Jens Axboe
5 */
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/blk-mq.h>
10 #include <trace/events/block.h>
12 #include "blk.h"
13 #include "blk-mq.h"
14 #include "blk-mq-sched.h"
15 #include "blk-mq-tag.h"
16 #include "blk-wbt.h"
18 void blk_mq_sched_free_hctx_data(struct request_queue *q,
19 void (*exit)(struct blk_mq_hw_ctx *))
21 struct blk_mq_hw_ctx *hctx;
22 int i;
24 queue_for_each_hw_ctx(q, hctx, i) {
25 if (exit && hctx->sched_data)
26 exit(hctx);
27 kfree(hctx->sched_data);
28 hctx->sched_data = NULL;
31 EXPORT_SYMBOL_GPL(blk_mq_sched_free_hctx_data);
33 int blk_mq_sched_init_hctx_data(struct request_queue *q, size_t size,
34 int (*init)(struct blk_mq_hw_ctx *),
35 void (*exit)(struct blk_mq_hw_ctx *))
37 struct blk_mq_hw_ctx *hctx;
38 int ret;
39 int i;
41 queue_for_each_hw_ctx(q, hctx, i) {
42 hctx->sched_data = kmalloc_node(size, GFP_KERNEL, hctx->numa_node);
43 if (!hctx->sched_data) {
44 ret = -ENOMEM;
45 goto error;
48 if (init) {
49 ret = init(hctx);
50 if (ret) {
52 * We don't want to give exit() a partially
53 * initialized sched_data. init() must clean up
54 * if it fails.
56 kfree(hctx->sched_data);
57 hctx->sched_data = NULL;
58 goto error;
63 return 0;
64 error:
65 blk_mq_sched_free_hctx_data(q, exit);
66 return ret;
68 EXPORT_SYMBOL_GPL(blk_mq_sched_init_hctx_data);
70 static void __blk_mq_sched_assign_ioc(struct request_queue *q,
71 struct request *rq,
72 struct bio *bio,
73 struct io_context *ioc)
75 struct io_cq *icq;
77 spin_lock_irq(q->queue_lock);
78 icq = ioc_lookup_icq(ioc, q);
79 spin_unlock_irq(q->queue_lock);
81 if (!icq) {
82 icq = ioc_create_icq(ioc, q, GFP_ATOMIC);
83 if (!icq)
84 return;
87 rq->elv.icq = icq;
88 if (!blk_mq_sched_get_rq_priv(q, rq, bio)) {
89 rq->rq_flags |= RQF_ELVPRIV;
90 get_io_context(icq->ioc);
91 return;
94 rq->elv.icq = NULL;
97 static void blk_mq_sched_assign_ioc(struct request_queue *q,
98 struct request *rq, struct bio *bio)
100 struct io_context *ioc;
102 ioc = rq_ioc(bio);
103 if (ioc)
104 __blk_mq_sched_assign_ioc(q, rq, bio, ioc);
107 struct request *blk_mq_sched_get_request(struct request_queue *q,
108 struct bio *bio,
109 unsigned int op,
110 struct blk_mq_alloc_data *data)
112 struct elevator_queue *e = q->elevator;
113 struct request *rq;
115 blk_queue_enter_live(q);
116 data->q = q;
117 if (likely(!data->ctx))
118 data->ctx = blk_mq_get_ctx(q);
119 if (likely(!data->hctx))
120 data->hctx = blk_mq_map_queue(q, data->ctx->cpu);
122 if (e) {
123 data->flags |= BLK_MQ_REQ_INTERNAL;
126 * Flush requests are special and go directly to the
127 * dispatch list.
129 if (!op_is_flush(op) && e->type->ops.mq.get_request) {
130 rq = e->type->ops.mq.get_request(q, op, data);
131 if (rq)
132 rq->rq_flags |= RQF_QUEUED;
133 } else
134 rq = __blk_mq_alloc_request(data, op);
135 } else {
136 rq = __blk_mq_alloc_request(data, op);
139 if (rq) {
140 if (!op_is_flush(op)) {
141 rq->elv.icq = NULL;
142 if (e && e->type->icq_cache)
143 blk_mq_sched_assign_ioc(q, rq, bio);
145 data->hctx->queued++;
146 return rq;
149 blk_queue_exit(q);
150 return NULL;
153 void blk_mq_sched_put_request(struct request *rq)
155 struct request_queue *q = rq->q;
156 struct elevator_queue *e = q->elevator;
158 if (rq->rq_flags & RQF_ELVPRIV) {
159 blk_mq_sched_put_rq_priv(rq->q, rq);
160 if (rq->elv.icq) {
161 put_io_context(rq->elv.icq->ioc);
162 rq->elv.icq = NULL;
166 if ((rq->rq_flags & RQF_QUEUED) && e && e->type->ops.mq.put_request)
167 e->type->ops.mq.put_request(rq);
168 else
169 blk_mq_finish_request(rq);
172 void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
174 struct request_queue *q = hctx->queue;
175 struct elevator_queue *e = q->elevator;
176 const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request;
177 bool did_work = false;
178 LIST_HEAD(rq_list);
180 if (unlikely(blk_mq_hctx_stopped(hctx)))
181 return;
183 hctx->run++;
186 * If we have previous entries on our dispatch list, grab them first for
187 * more fair dispatch.
189 if (!list_empty_careful(&hctx->dispatch)) {
190 spin_lock(&hctx->lock);
191 if (!list_empty(&hctx->dispatch))
192 list_splice_init(&hctx->dispatch, &rq_list);
193 spin_unlock(&hctx->lock);
197 * Only ask the scheduler for requests, if we didn't have residual
198 * requests from the dispatch list. This is to avoid the case where
199 * we only ever dispatch a fraction of the requests available because
200 * of low device queue depth. Once we pull requests out of the IO
201 * scheduler, we can no longer merge or sort them. So it's best to
202 * leave them there for as long as we can. Mark the hw queue as
203 * needing a restart in that case.
205 if (!list_empty(&rq_list)) {
206 blk_mq_sched_mark_restart_hctx(hctx);
207 did_work = blk_mq_dispatch_rq_list(q, &rq_list);
208 } else if (!has_sched_dispatch) {
209 blk_mq_flush_busy_ctxs(hctx, &rq_list);
210 blk_mq_dispatch_rq_list(q, &rq_list);
214 * We want to dispatch from the scheduler if we had no work left
215 * on the dispatch list, OR if we did have work but weren't able
216 * to make progress.
218 if (!did_work && has_sched_dispatch) {
219 do {
220 struct request *rq;
222 rq = e->type->ops.mq.dispatch_request(hctx);
223 if (!rq)
224 break;
225 list_add(&rq->queuelist, &rq_list);
226 } while (blk_mq_dispatch_rq_list(q, &rq_list));
230 void blk_mq_sched_move_to_dispatch(struct blk_mq_hw_ctx *hctx,
231 struct list_head *rq_list,
232 struct request *(*get_rq)(struct blk_mq_hw_ctx *))
234 do {
235 struct request *rq;
237 rq = get_rq(hctx);
238 if (!rq)
239 break;
241 list_add_tail(&rq->queuelist, rq_list);
242 } while (1);
244 EXPORT_SYMBOL_GPL(blk_mq_sched_move_to_dispatch);
246 bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
247 struct request **merged_request)
249 struct request *rq;
251 switch (elv_merge(q, &rq, bio)) {
252 case ELEVATOR_BACK_MERGE:
253 if (!blk_mq_sched_allow_merge(q, rq, bio))
254 return false;
255 if (!bio_attempt_back_merge(q, rq, bio))
256 return false;
257 *merged_request = attempt_back_merge(q, rq);
258 if (!*merged_request)
259 elv_merged_request(q, rq, ELEVATOR_BACK_MERGE);
260 return true;
261 case ELEVATOR_FRONT_MERGE:
262 if (!blk_mq_sched_allow_merge(q, rq, bio))
263 return false;
264 if (!bio_attempt_front_merge(q, rq, bio))
265 return false;
266 *merged_request = attempt_front_merge(q, rq);
267 if (!*merged_request)
268 elv_merged_request(q, rq, ELEVATOR_FRONT_MERGE);
269 return true;
270 default:
271 return false;
274 EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
276 bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio)
278 struct elevator_queue *e = q->elevator;
280 if (e->type->ops.mq.bio_merge) {
281 struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
282 struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
284 blk_mq_put_ctx(ctx);
285 return e->type->ops.mq.bio_merge(hctx, bio);
288 return false;
291 bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq)
293 return rq_mergeable(rq) && elv_attempt_insert_merge(q, rq);
295 EXPORT_SYMBOL_GPL(blk_mq_sched_try_insert_merge);
297 void blk_mq_sched_request_inserted(struct request *rq)
299 trace_block_rq_insert(rq->q, rq);
301 EXPORT_SYMBOL_GPL(blk_mq_sched_request_inserted);
303 static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx,
304 struct request *rq)
306 if (rq->tag == -1) {
307 rq->rq_flags |= RQF_SORTED;
308 return false;
312 * If we already have a real request tag, send directly to
313 * the dispatch list.
315 spin_lock(&hctx->lock);
316 list_add(&rq->queuelist, &hctx->dispatch);
317 spin_unlock(&hctx->lock);
318 return true;
321 static bool blk_mq_sched_restart_hctx(struct blk_mq_hw_ctx *hctx)
323 if (test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) {
324 clear_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
325 if (blk_mq_hctx_has_pending(hctx)) {
326 blk_mq_run_hw_queue(hctx, true);
327 return true;
330 return false;
334 * list_for_each_entry_rcu_rr - iterate in a round-robin fashion over rcu list
335 * @pos: loop cursor.
336 * @skip: the list element that will not be examined. Iteration starts at
337 * @skip->next.
338 * @head: head of the list to examine. This list must have at least one
339 * element, namely @skip.
340 * @member: name of the list_head structure within typeof(*pos).
342 #define list_for_each_entry_rcu_rr(pos, skip, head, member) \
343 for ((pos) = (skip); \
344 (pos = (pos)->member.next != (head) ? list_entry_rcu( \
345 (pos)->member.next, typeof(*pos), member) : \
346 list_entry_rcu((pos)->member.next->next, typeof(*pos), member)), \
347 (pos) != (skip); )
350 * Called after a driver tag has been freed to check whether a hctx needs to
351 * be restarted. Restarts @hctx if its tag set is not shared. Restarts hardware
352 * queues in a round-robin fashion if the tag set of @hctx is shared with other
353 * hardware queues.
355 void blk_mq_sched_restart(struct blk_mq_hw_ctx *const hctx)
357 struct blk_mq_tags *const tags = hctx->tags;
358 struct blk_mq_tag_set *const set = hctx->queue->tag_set;
359 struct request_queue *const queue = hctx->queue, *q;
360 struct blk_mq_hw_ctx *hctx2;
361 unsigned int i, j;
363 if (set->flags & BLK_MQ_F_TAG_SHARED) {
364 rcu_read_lock();
365 list_for_each_entry_rcu_rr(q, queue, &set->tag_list,
366 tag_set_list) {
367 queue_for_each_hw_ctx(q, hctx2, i)
368 if (hctx2->tags == tags &&
369 blk_mq_sched_restart_hctx(hctx2))
370 goto done;
372 j = hctx->queue_num + 1;
373 for (i = 0; i < queue->nr_hw_queues; i++, j++) {
374 if (j == queue->nr_hw_queues)
375 j = 0;
376 hctx2 = queue->queue_hw_ctx[j];
377 if (hctx2->tags == tags &&
378 blk_mq_sched_restart_hctx(hctx2))
379 break;
381 done:
382 rcu_read_unlock();
383 } else {
384 blk_mq_sched_restart_hctx(hctx);
389 * Add flush/fua to the queue. If we fail getting a driver tag, then
390 * punt to the requeue list. Requeue will re-invoke us from a context
391 * that's safe to block from.
393 static void blk_mq_sched_insert_flush(struct blk_mq_hw_ctx *hctx,
394 struct request *rq, bool can_block)
396 if (blk_mq_get_driver_tag(rq, &hctx, can_block)) {
397 blk_insert_flush(rq);
398 blk_mq_run_hw_queue(hctx, true);
399 } else
400 blk_mq_add_to_requeue_list(rq, false, true);
403 void blk_mq_sched_insert_request(struct request *rq, bool at_head,
404 bool run_queue, bool async, bool can_block)
406 struct request_queue *q = rq->q;
407 struct elevator_queue *e = q->elevator;
408 struct blk_mq_ctx *ctx = rq->mq_ctx;
409 struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
411 if (rq->tag == -1 && op_is_flush(rq->cmd_flags)) {
412 blk_mq_sched_insert_flush(hctx, rq, can_block);
413 return;
416 if (e && blk_mq_sched_bypass_insert(hctx, rq))
417 goto run;
419 if (e && e->type->ops.mq.insert_requests) {
420 LIST_HEAD(list);
422 list_add(&rq->queuelist, &list);
423 e->type->ops.mq.insert_requests(hctx, &list, at_head);
424 } else {
425 spin_lock(&ctx->lock);
426 __blk_mq_insert_request(hctx, rq, at_head);
427 spin_unlock(&ctx->lock);
430 run:
431 if (run_queue)
432 blk_mq_run_hw_queue(hctx, async);
435 void blk_mq_sched_insert_requests(struct request_queue *q,
436 struct blk_mq_ctx *ctx,
437 struct list_head *list, bool run_queue_async)
439 struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
440 struct elevator_queue *e = hctx->queue->elevator;
442 if (e) {
443 struct request *rq, *next;
446 * We bypass requests that already have a driver tag assigned,
447 * which should only be flushes. Flushes are only ever inserted
448 * as single requests, so we shouldn't ever hit the
449 * WARN_ON_ONCE() below (but let's handle it just in case).
451 list_for_each_entry_safe(rq, next, list, queuelist) {
452 if (WARN_ON_ONCE(rq->tag != -1)) {
453 list_del_init(&rq->queuelist);
454 blk_mq_sched_bypass_insert(hctx, rq);
459 if (e && e->type->ops.mq.insert_requests)
460 e->type->ops.mq.insert_requests(hctx, list, false);
461 else
462 blk_mq_insert_requests(hctx, ctx, list);
464 blk_mq_run_hw_queue(hctx, run_queue_async);
467 static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set,
468 struct blk_mq_hw_ctx *hctx,
469 unsigned int hctx_idx)
471 if (hctx->sched_tags) {
472 blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx);
473 blk_mq_free_rq_map(hctx->sched_tags);
474 hctx->sched_tags = NULL;
478 static int blk_mq_sched_alloc_tags(struct request_queue *q,
479 struct blk_mq_hw_ctx *hctx,
480 unsigned int hctx_idx)
482 struct blk_mq_tag_set *set = q->tag_set;
483 int ret;
485 hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,
486 set->reserved_tags);
487 if (!hctx->sched_tags)
488 return -ENOMEM;
490 ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests);
491 if (ret)
492 blk_mq_sched_free_tags(set, hctx, hctx_idx);
494 return ret;
497 static void blk_mq_sched_tags_teardown(struct request_queue *q)
499 struct blk_mq_tag_set *set = q->tag_set;
500 struct blk_mq_hw_ctx *hctx;
501 int i;
503 queue_for_each_hw_ctx(q, hctx, i)
504 blk_mq_sched_free_tags(set, hctx, i);
507 int blk_mq_sched_init_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
508 unsigned int hctx_idx)
510 struct elevator_queue *e = q->elevator;
512 if (!e)
513 return 0;
515 return blk_mq_sched_alloc_tags(q, hctx, hctx_idx);
518 void blk_mq_sched_exit_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
519 unsigned int hctx_idx)
521 struct elevator_queue *e = q->elevator;
523 if (!e)
524 return;
526 blk_mq_sched_free_tags(q->tag_set, hctx, hctx_idx);
529 int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
531 struct blk_mq_hw_ctx *hctx;
532 unsigned int i;
533 int ret;
535 if (!e) {
536 q->elevator = NULL;
537 return 0;
541 * Default to 256, since we don't split into sync/async like the
542 * old code did. Additionally, this is a per-hw queue depth.
544 q->nr_requests = 2 * BLKDEV_MAX_RQ;
546 queue_for_each_hw_ctx(q, hctx, i) {
547 ret = blk_mq_sched_alloc_tags(q, hctx, i);
548 if (ret)
549 goto err;
552 ret = e->ops.mq.init_sched(q, e);
553 if (ret)
554 goto err;
556 return 0;
558 err:
559 blk_mq_sched_tags_teardown(q);
560 q->elevator = NULL;
561 return ret;
564 void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e)
566 if (e->type->ops.mq.exit_sched)
567 e->type->ops.mq.exit_sched(e);
568 blk_mq_sched_tags_teardown(q);
569 q->elevator = NULL;
572 int blk_mq_sched_init(struct request_queue *q)
574 int ret;
576 mutex_lock(&q->sysfs_lock);
577 ret = elevator_init(q, NULL);
578 mutex_unlock(&q->sysfs_lock);
580 return ret;