2 * Block multiqueue core code
4 * Copyright (C) 2013-2014 Jens Axboe
5 * Copyright (C) 2013-2014 Christoph Hellwig
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/backing-dev.h>
10 #include <linux/bio.h>
11 #include <linux/blkdev.h>
13 #include <linux/init.h>
14 #include <linux/slab.h>
15 #include <linux/workqueue.h>
16 #include <linux/smp.h>
17 #include <linux/llist.h>
18 #include <linux/list_sort.h>
19 #include <linux/cpu.h>
20 #include <linux/cache.h>
21 #include <linux/sched/sysctl.h>
22 #include <linux/delay.h>
24 #include <trace/events/block.h>
26 #include <linux/blk-mq.h>
29 #include "blk-mq-tag.h"
31 static DEFINE_MUTEX(all_q_mutex
);
32 static LIST_HEAD(all_q_list
);
34 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
);
37 * Check if any of the ctx's have pending work in this hardware queue
39 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
43 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++)
44 if (hctx
->ctx_map
.map
[i
].word
)
50 static inline struct blk_align_bitmap
*get_bm(struct blk_mq_hw_ctx
*hctx
,
51 struct blk_mq_ctx
*ctx
)
53 return &hctx
->ctx_map
.map
[ctx
->index_hw
/ hctx
->ctx_map
.bits_per_word
];
56 #define CTX_TO_BIT(hctx, ctx) \
57 ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1))
60 * Mark this ctx as having pending work in this hardware queue
62 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
63 struct blk_mq_ctx
*ctx
)
65 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
67 if (!test_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
))
68 set_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
71 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
72 struct blk_mq_ctx
*ctx
)
74 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
76 clear_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
79 static int blk_mq_queue_enter(struct request_queue
*q
)
84 if (percpu_ref_tryget_live(&q
->mq_usage_counter
))
87 ret
= wait_event_interruptible(q
->mq_freeze_wq
,
88 !q
->mq_freeze_depth
|| blk_queue_dying(q
));
89 if (blk_queue_dying(q
))
96 static void blk_mq_queue_exit(struct request_queue
*q
)
98 percpu_ref_put(&q
->mq_usage_counter
);
101 static void blk_mq_usage_counter_release(struct percpu_ref
*ref
)
103 struct request_queue
*q
=
104 container_of(ref
, struct request_queue
, mq_usage_counter
);
106 wake_up_all(&q
->mq_freeze_wq
);
110 * Guarantee no request is in use, so we can change any data structure of
111 * the queue afterward.
113 void blk_mq_freeze_queue(struct request_queue
*q
)
117 spin_lock_irq(q
->queue_lock
);
118 freeze
= !q
->mq_freeze_depth
++;
119 spin_unlock_irq(q
->queue_lock
);
122 percpu_ref_kill(&q
->mq_usage_counter
);
123 blk_mq_run_queues(q
, false);
125 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->mq_usage_counter
));
128 static void blk_mq_unfreeze_queue(struct request_queue
*q
)
132 spin_lock_irq(q
->queue_lock
);
133 wake
= !--q
->mq_freeze_depth
;
134 WARN_ON_ONCE(q
->mq_freeze_depth
< 0);
135 spin_unlock_irq(q
->queue_lock
);
137 percpu_ref_reinit(&q
->mq_usage_counter
);
138 wake_up_all(&q
->mq_freeze_wq
);
142 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
144 return blk_mq_has_free_tags(hctx
->tags
);
146 EXPORT_SYMBOL(blk_mq_can_queue
);
148 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
149 struct request
*rq
, unsigned int rw_flags
)
151 if (blk_queue_io_stat(q
))
152 rw_flags
|= REQ_IO_STAT
;
154 INIT_LIST_HEAD(&rq
->queuelist
);
155 /* csd/requeue_work/fifo_time is initialized before use */
158 rq
->cmd_flags
|= rw_flags
;
159 /* do not touch atomic flags, it needs atomic ops against the timer */
161 INIT_HLIST_NODE(&rq
->hash
);
162 RB_CLEAR_NODE(&rq
->rb_node
);
165 rq
->start_time
= jiffies
;
166 #ifdef CONFIG_BLK_CGROUP
168 set_start_time_ns(rq
);
169 rq
->io_start_time_ns
= 0;
171 rq
->nr_phys_segments
= 0;
172 #if defined(CONFIG_BLK_DEV_INTEGRITY)
173 rq
->nr_integrity_segments
= 0;
176 /* tag was already set */
186 INIT_LIST_HEAD(&rq
->timeout_list
);
190 rq
->end_io_data
= NULL
;
193 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
196 static struct request
*
197 __blk_mq_alloc_request(struct blk_mq_alloc_data
*data
, int rw
)
202 tag
= blk_mq_get_tag(data
);
203 if (tag
!= BLK_MQ_TAG_FAIL
) {
204 rq
= data
->hctx
->tags
->rqs
[tag
];
206 if (blk_mq_tag_busy(data
->hctx
)) {
207 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
208 atomic_inc(&data
->hctx
->nr_active
);
212 blk_mq_rq_ctx_init(data
->q
, data
->ctx
, rq
, rw
);
219 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
,
222 struct blk_mq_ctx
*ctx
;
223 struct blk_mq_hw_ctx
*hctx
;
225 struct blk_mq_alloc_data alloc_data
;
227 if (blk_mq_queue_enter(q
))
230 ctx
= blk_mq_get_ctx(q
);
231 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
232 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
& ~__GFP_WAIT
,
233 reserved
, ctx
, hctx
);
235 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
236 if (!rq
&& (gfp
& __GFP_WAIT
)) {
237 __blk_mq_run_hw_queue(hctx
);
240 ctx
= blk_mq_get_ctx(q
);
241 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
242 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
, reserved
, ctx
,
244 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
245 ctx
= alloc_data
.ctx
;
250 EXPORT_SYMBOL(blk_mq_alloc_request
);
252 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
253 struct blk_mq_ctx
*ctx
, struct request
*rq
)
255 const int tag
= rq
->tag
;
256 struct request_queue
*q
= rq
->q
;
258 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
259 atomic_dec(&hctx
->nr_active
);
262 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
263 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
264 blk_mq_queue_exit(q
);
267 void blk_mq_free_request(struct request
*rq
)
269 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
270 struct blk_mq_hw_ctx
*hctx
;
271 struct request_queue
*q
= rq
->q
;
273 ctx
->rq_completed
[rq_is_sync(rq
)]++;
275 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
276 __blk_mq_free_request(hctx
, ctx
, rq
);
280 * Clone all relevant state from a request that has been put on hold in
281 * the flush state machine into the preallocated flush request that hangs
282 * off the request queue.
284 * For a driver the flush request should be invisible, that's why we are
285 * impersonating the original request here.
287 void blk_mq_clone_flush_request(struct request
*flush_rq
,
288 struct request
*orig_rq
)
290 struct blk_mq_hw_ctx
*hctx
=
291 orig_rq
->q
->mq_ops
->map_queue(orig_rq
->q
, orig_rq
->mq_ctx
->cpu
);
293 flush_rq
->mq_ctx
= orig_rq
->mq_ctx
;
294 flush_rq
->tag
= orig_rq
->tag
;
295 memcpy(blk_mq_rq_to_pdu(flush_rq
), blk_mq_rq_to_pdu(orig_rq
),
299 inline void __blk_mq_end_io(struct request
*rq
, int error
)
301 blk_account_io_done(rq
);
304 rq
->end_io(rq
, error
);
306 if (unlikely(blk_bidi_rq(rq
)))
307 blk_mq_free_request(rq
->next_rq
);
308 blk_mq_free_request(rq
);
311 EXPORT_SYMBOL(__blk_mq_end_io
);
313 void blk_mq_end_io(struct request
*rq
, int error
)
315 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
317 __blk_mq_end_io(rq
, error
);
319 EXPORT_SYMBOL(blk_mq_end_io
);
321 static void __blk_mq_complete_request_remote(void *data
)
323 struct request
*rq
= data
;
325 rq
->q
->softirq_done_fn(rq
);
328 static void blk_mq_ipi_complete_request(struct request
*rq
)
330 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
334 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
335 rq
->q
->softirq_done_fn(rq
);
340 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
341 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
343 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
344 rq
->csd
.func
= __blk_mq_complete_request_remote
;
347 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
349 rq
->q
->softirq_done_fn(rq
);
354 void __blk_mq_complete_request(struct request
*rq
)
356 struct request_queue
*q
= rq
->q
;
358 if (!q
->softirq_done_fn
)
359 blk_mq_end_io(rq
, rq
->errors
);
361 blk_mq_ipi_complete_request(rq
);
365 * blk_mq_complete_request - end I/O on a request
366 * @rq: the request being processed
369 * Ends all I/O on a request. It does not handle partial completions.
370 * The actual completion happens out-of-order, through a IPI handler.
372 void blk_mq_complete_request(struct request
*rq
)
374 struct request_queue
*q
= rq
->q
;
376 if (unlikely(blk_should_fake_timeout(q
)))
378 if (!blk_mark_rq_complete(rq
))
379 __blk_mq_complete_request(rq
);
381 EXPORT_SYMBOL(blk_mq_complete_request
);
383 static void blk_mq_start_request(struct request
*rq
, bool last
)
385 struct request_queue
*q
= rq
->q
;
387 trace_block_rq_issue(q
, rq
);
389 rq
->resid_len
= blk_rq_bytes(rq
);
390 if (unlikely(blk_bidi_rq(rq
)))
391 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
396 * Ensure that ->deadline is visible before set the started
397 * flag and clear the completed flag.
399 smp_mb__before_atomic();
402 * Mark us as started and clear complete. Complete might have been
403 * set if requeue raced with timeout, which then marked it as
404 * complete. So be sure to clear complete again when we start
405 * the request, otherwise we'll ignore the completion event.
407 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
408 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
409 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
410 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
412 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
414 * Make sure space for the drain appears. We know we can do
415 * this because max_hw_segments has been adjusted to be one
416 * fewer than the device can handle.
418 rq
->nr_phys_segments
++;
422 * Flag the last request in the series so that drivers know when IO
423 * should be kicked off, if they don't do it on a per-request basis.
425 * Note: the flag isn't the only condition drivers should do kick off.
426 * If drive is busy, the last request might not have the bit set.
429 rq
->cmd_flags
|= REQ_END
;
432 static void __blk_mq_requeue_request(struct request
*rq
)
434 struct request_queue
*q
= rq
->q
;
436 trace_block_rq_requeue(q
, rq
);
437 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
439 rq
->cmd_flags
&= ~REQ_END
;
441 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
442 rq
->nr_phys_segments
--;
445 void blk_mq_requeue_request(struct request
*rq
)
447 __blk_mq_requeue_request(rq
);
448 blk_clear_rq_complete(rq
);
450 BUG_ON(blk_queued_rq(rq
));
451 blk_mq_add_to_requeue_list(rq
, true);
453 EXPORT_SYMBOL(blk_mq_requeue_request
);
455 static void blk_mq_requeue_work(struct work_struct
*work
)
457 struct request_queue
*q
=
458 container_of(work
, struct request_queue
, requeue_work
);
460 struct request
*rq
, *next
;
463 spin_lock_irqsave(&q
->requeue_lock
, flags
);
464 list_splice_init(&q
->requeue_list
, &rq_list
);
465 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
467 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
468 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
471 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
472 list_del_init(&rq
->queuelist
);
473 blk_mq_insert_request(rq
, true, false, false);
476 while (!list_empty(&rq_list
)) {
477 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
478 list_del_init(&rq
->queuelist
);
479 blk_mq_insert_request(rq
, false, false, false);
483 * Use the start variant of queue running here, so that running
484 * the requeue work will kick stopped queues.
486 blk_mq_start_hw_queues(q
);
489 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
491 struct request_queue
*q
= rq
->q
;
495 * We abuse this flag that is otherwise used by the I/O scheduler to
496 * request head insertation from the workqueue.
498 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
500 spin_lock_irqsave(&q
->requeue_lock
, flags
);
502 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
503 list_add(&rq
->queuelist
, &q
->requeue_list
);
505 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
507 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
509 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
511 void blk_mq_kick_requeue_list(struct request_queue
*q
)
513 kblockd_schedule_work(&q
->requeue_work
);
515 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
517 static inline bool is_flush_request(struct request
*rq
, unsigned int tag
)
519 return ((rq
->cmd_flags
& REQ_FLUSH_SEQ
) &&
520 rq
->q
->flush_rq
->tag
== tag
);
523 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
525 struct request
*rq
= tags
->rqs
[tag
];
527 if (!is_flush_request(rq
, tag
))
530 return rq
->q
->flush_rq
;
532 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
534 struct blk_mq_timeout_data
{
535 struct blk_mq_hw_ctx
*hctx
;
537 unsigned int *next_set
;
540 static void blk_mq_timeout_check(void *__data
, unsigned long *free_tags
)
542 struct blk_mq_timeout_data
*data
= __data
;
543 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
546 /* It may not be in flight yet (this is where
547 * the REQ_ATOMIC_STARTED flag comes in). The requests are
548 * statically allocated, so we know it's always safe to access the
549 * memory associated with a bit offset into ->rqs[].
555 tag
= find_next_zero_bit(free_tags
, hctx
->tags
->nr_tags
, tag
);
556 if (tag
>= hctx
->tags
->nr_tags
)
559 rq
= blk_mq_tag_to_rq(hctx
->tags
, tag
++);
560 if (rq
->q
!= hctx
->queue
)
562 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
565 blk_rq_check_expired(rq
, data
->next
, data
->next_set
);
569 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx
*hctx
,
571 unsigned int *next_set
)
573 struct blk_mq_timeout_data data
= {
576 .next_set
= next_set
,
580 * Ask the tagging code to iterate busy requests, so we can
581 * check them for timeout.
583 blk_mq_tag_busy_iter(hctx
->tags
, blk_mq_timeout_check
, &data
);
586 static enum blk_eh_timer_return
blk_mq_rq_timed_out(struct request
*rq
)
588 struct request_queue
*q
= rq
->q
;
591 * We know that complete is set at this point. If STARTED isn't set
592 * anymore, then the request isn't active and the "timeout" should
593 * just be ignored. This can happen due to the bitflag ordering.
594 * Timeout first checks if STARTED is set, and if it is, assumes
595 * the request is active. But if we race with completion, then
596 * we both flags will get cleared. So check here again, and ignore
597 * a timeout event with a request that isn't active.
599 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
600 return BLK_EH_NOT_HANDLED
;
602 if (!q
->mq_ops
->timeout
)
603 return BLK_EH_RESET_TIMER
;
605 return q
->mq_ops
->timeout(rq
);
608 static void blk_mq_rq_timer(unsigned long data
)
610 struct request_queue
*q
= (struct request_queue
*) data
;
611 struct blk_mq_hw_ctx
*hctx
;
612 unsigned long next
= 0;
615 queue_for_each_hw_ctx(q
, hctx
, i
) {
617 * If not software queues are currently mapped to this
618 * hardware queue, there's nothing to check
620 if (!hctx
->nr_ctx
|| !hctx
->tags
)
623 blk_mq_hw_ctx_check_timeout(hctx
, &next
, &next_set
);
627 next
= blk_rq_timeout(round_jiffies_up(next
));
628 mod_timer(&q
->timeout
, next
);
630 queue_for_each_hw_ctx(q
, hctx
, i
)
631 blk_mq_tag_idle(hctx
);
636 * Reverse check our software queue for entries that we could potentially
637 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
638 * too much time checking for merges.
640 static bool blk_mq_attempt_merge(struct request_queue
*q
,
641 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
646 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
652 if (!blk_rq_merge_ok(rq
, bio
))
655 el_ret
= blk_try_merge(rq
, bio
);
656 if (el_ret
== ELEVATOR_BACK_MERGE
) {
657 if (bio_attempt_back_merge(q
, rq
, bio
)) {
662 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
663 if (bio_attempt_front_merge(q
, rq
, bio
)) {
675 * Process software queues that have been marked busy, splicing them
676 * to the for-dispatch
678 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
680 struct blk_mq_ctx
*ctx
;
683 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++) {
684 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
685 unsigned int off
, bit
;
691 off
= i
* hctx
->ctx_map
.bits_per_word
;
693 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
694 if (bit
>= bm
->depth
)
697 ctx
= hctx
->ctxs
[bit
+ off
];
698 clear_bit(bit
, &bm
->word
);
699 spin_lock(&ctx
->lock
);
700 list_splice_tail_init(&ctx
->rq_list
, list
);
701 spin_unlock(&ctx
->lock
);
709 * Run this hardware queue, pulling any software queues mapped to it in.
710 * Note that this function currently has various problems around ordering
711 * of IO. In particular, we'd like FIFO behaviour on handling existing
712 * items on the hctx->dispatch list. Ignore that for now.
714 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
716 struct request_queue
*q
= hctx
->queue
;
721 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
723 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
729 * Touch any software queue that has pending entries.
731 flush_busy_ctxs(hctx
, &rq_list
);
734 * If we have previous entries on our dispatch list, grab them
735 * and stuff them at the front for more fair dispatch.
737 if (!list_empty_careful(&hctx
->dispatch
)) {
738 spin_lock(&hctx
->lock
);
739 if (!list_empty(&hctx
->dispatch
))
740 list_splice_init(&hctx
->dispatch
, &rq_list
);
741 spin_unlock(&hctx
->lock
);
745 * Now process all the entries, sending them to the driver.
748 while (!list_empty(&rq_list
)) {
751 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
752 list_del_init(&rq
->queuelist
);
754 blk_mq_start_request(rq
, list_empty(&rq_list
));
756 ret
= q
->mq_ops
->queue_rq(hctx
, rq
);
758 case BLK_MQ_RQ_QUEUE_OK
:
761 case BLK_MQ_RQ_QUEUE_BUSY
:
762 list_add(&rq
->queuelist
, &rq_list
);
763 __blk_mq_requeue_request(rq
);
766 pr_err("blk-mq: bad return on queue: %d\n", ret
);
767 case BLK_MQ_RQ_QUEUE_ERROR
:
769 blk_mq_end_io(rq
, rq
->errors
);
773 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
778 hctx
->dispatched
[0]++;
779 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
780 hctx
->dispatched
[ilog2(queued
) + 1]++;
783 * Any items that need requeuing? Stuff them into hctx->dispatch,
784 * that is where we will continue on next queue run.
786 if (!list_empty(&rq_list
)) {
787 spin_lock(&hctx
->lock
);
788 list_splice(&rq_list
, &hctx
->dispatch
);
789 spin_unlock(&hctx
->lock
);
794 * It'd be great if the workqueue API had a way to pass
795 * in a mask and had some smarts for more clever placement.
796 * For now we just round-robin here, switching for every
797 * BLK_MQ_CPU_WORK_BATCH queued items.
799 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
801 int cpu
= hctx
->next_cpu
;
803 if (--hctx
->next_cpu_batch
<= 0) {
806 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
807 if (next_cpu
>= nr_cpu_ids
)
808 next_cpu
= cpumask_first(hctx
->cpumask
);
810 hctx
->next_cpu
= next_cpu
;
811 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
817 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
819 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
822 if (!async
&& cpumask_test_cpu(smp_processor_id(), hctx
->cpumask
))
823 __blk_mq_run_hw_queue(hctx
);
824 else if (hctx
->queue
->nr_hw_queues
== 1)
825 kblockd_schedule_delayed_work(&hctx
->run_work
, 0);
829 cpu
= blk_mq_hctx_next_cpu(hctx
);
830 kblockd_schedule_delayed_work_on(cpu
, &hctx
->run_work
, 0);
834 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
836 struct blk_mq_hw_ctx
*hctx
;
839 queue_for_each_hw_ctx(q
, hctx
, i
) {
840 if ((!blk_mq_hctx_has_pending(hctx
) &&
841 list_empty_careful(&hctx
->dispatch
)) ||
842 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
846 blk_mq_run_hw_queue(hctx
, async
);
850 EXPORT_SYMBOL(blk_mq_run_queues
);
852 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
854 cancel_delayed_work(&hctx
->run_work
);
855 cancel_delayed_work(&hctx
->delay_work
);
856 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
858 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
860 void blk_mq_stop_hw_queues(struct request_queue
*q
)
862 struct blk_mq_hw_ctx
*hctx
;
865 queue_for_each_hw_ctx(q
, hctx
, i
)
866 blk_mq_stop_hw_queue(hctx
);
868 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
870 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
872 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
875 blk_mq_run_hw_queue(hctx
, false);
878 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
880 void blk_mq_start_hw_queues(struct request_queue
*q
)
882 struct blk_mq_hw_ctx
*hctx
;
885 queue_for_each_hw_ctx(q
, hctx
, i
)
886 blk_mq_start_hw_queue(hctx
);
888 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
891 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
893 struct blk_mq_hw_ctx
*hctx
;
896 queue_for_each_hw_ctx(q
, hctx
, i
) {
897 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
900 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
902 blk_mq_run_hw_queue(hctx
, async
);
906 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
908 static void blk_mq_run_work_fn(struct work_struct
*work
)
910 struct blk_mq_hw_ctx
*hctx
;
912 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
914 __blk_mq_run_hw_queue(hctx
);
917 static void blk_mq_delay_work_fn(struct work_struct
*work
)
919 struct blk_mq_hw_ctx
*hctx
;
921 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
923 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
924 __blk_mq_run_hw_queue(hctx
);
927 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
929 unsigned long tmo
= msecs_to_jiffies(msecs
);
931 if (hctx
->queue
->nr_hw_queues
== 1)
932 kblockd_schedule_delayed_work(&hctx
->delay_work
, tmo
);
936 cpu
= blk_mq_hctx_next_cpu(hctx
);
937 kblockd_schedule_delayed_work_on(cpu
, &hctx
->delay_work
, tmo
);
940 EXPORT_SYMBOL(blk_mq_delay_queue
);
942 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
943 struct request
*rq
, bool at_head
)
945 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
947 trace_block_rq_insert(hctx
->queue
, rq
);
950 list_add(&rq
->queuelist
, &ctx
->rq_list
);
952 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
954 blk_mq_hctx_mark_pending(hctx
, ctx
);
957 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
960 struct request_queue
*q
= rq
->q
;
961 struct blk_mq_hw_ctx
*hctx
;
962 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
964 current_ctx
= blk_mq_get_ctx(q
);
965 if (!cpu_online(ctx
->cpu
))
966 rq
->mq_ctx
= ctx
= current_ctx
;
968 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
970 spin_lock(&ctx
->lock
);
971 __blk_mq_insert_request(hctx
, rq
, at_head
);
972 spin_unlock(&ctx
->lock
);
975 blk_mq_run_hw_queue(hctx
, async
);
977 blk_mq_put_ctx(current_ctx
);
980 static void blk_mq_insert_requests(struct request_queue
*q
,
981 struct blk_mq_ctx
*ctx
,
982 struct list_head
*list
,
987 struct blk_mq_hw_ctx
*hctx
;
988 struct blk_mq_ctx
*current_ctx
;
990 trace_block_unplug(q
, depth
, !from_schedule
);
992 current_ctx
= blk_mq_get_ctx(q
);
994 if (!cpu_online(ctx
->cpu
))
996 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
999 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1002 spin_lock(&ctx
->lock
);
1003 while (!list_empty(list
)) {
1006 rq
= list_first_entry(list
, struct request
, queuelist
);
1007 list_del_init(&rq
->queuelist
);
1009 __blk_mq_insert_request(hctx
, rq
, false);
1011 spin_unlock(&ctx
->lock
);
1013 blk_mq_run_hw_queue(hctx
, from_schedule
);
1014 blk_mq_put_ctx(current_ctx
);
1017 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1019 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1020 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1022 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1023 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1024 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1027 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1029 struct blk_mq_ctx
*this_ctx
;
1030 struct request_queue
*this_q
;
1033 LIST_HEAD(ctx_list
);
1036 list_splice_init(&plug
->mq_list
, &list
);
1038 list_sort(NULL
, &list
, plug_ctx_cmp
);
1044 while (!list_empty(&list
)) {
1045 rq
= list_entry_rq(list
.next
);
1046 list_del_init(&rq
->queuelist
);
1048 if (rq
->mq_ctx
!= this_ctx
) {
1050 blk_mq_insert_requests(this_q
, this_ctx
,
1055 this_ctx
= rq
->mq_ctx
;
1061 list_add_tail(&rq
->queuelist
, &ctx_list
);
1065 * If 'this_ctx' is set, we know we have entries to complete
1066 * on 'ctx_list'. Do those.
1069 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1074 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1076 init_request_from_bio(rq
, bio
);
1078 if (blk_do_io_stat(rq
))
1079 blk_account_io_start(rq
, 1);
1082 static inline bool hctx_allow_merges(struct blk_mq_hw_ctx
*hctx
)
1084 return (hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
1085 !blk_queue_nomerges(hctx
->queue
);
1088 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1089 struct blk_mq_ctx
*ctx
,
1090 struct request
*rq
, struct bio
*bio
)
1092 if (!hctx_allow_merges(hctx
)) {
1093 blk_mq_bio_to_request(rq
, bio
);
1094 spin_lock(&ctx
->lock
);
1096 __blk_mq_insert_request(hctx
, rq
, false);
1097 spin_unlock(&ctx
->lock
);
1100 struct request_queue
*q
= hctx
->queue
;
1102 spin_lock(&ctx
->lock
);
1103 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1104 blk_mq_bio_to_request(rq
, bio
);
1108 spin_unlock(&ctx
->lock
);
1109 __blk_mq_free_request(hctx
, ctx
, rq
);
1114 struct blk_map_ctx
{
1115 struct blk_mq_hw_ctx
*hctx
;
1116 struct blk_mq_ctx
*ctx
;
1119 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1121 struct blk_map_ctx
*data
)
1123 struct blk_mq_hw_ctx
*hctx
;
1124 struct blk_mq_ctx
*ctx
;
1126 int rw
= bio_data_dir(bio
);
1127 struct blk_mq_alloc_data alloc_data
;
1129 if (unlikely(blk_mq_queue_enter(q
))) {
1130 bio_endio(bio
, -EIO
);
1134 ctx
= blk_mq_get_ctx(q
);
1135 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1137 if (rw_is_sync(bio
->bi_rw
))
1140 trace_block_getrq(q
, bio
, rw
);
1141 blk_mq_set_alloc_data(&alloc_data
, q
, GFP_ATOMIC
, false, ctx
,
1143 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1144 if (unlikely(!rq
)) {
1145 __blk_mq_run_hw_queue(hctx
);
1146 blk_mq_put_ctx(ctx
);
1147 trace_block_sleeprq(q
, bio
, rw
);
1149 ctx
= blk_mq_get_ctx(q
);
1150 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1151 blk_mq_set_alloc_data(&alloc_data
, q
,
1152 __GFP_WAIT
|GFP_ATOMIC
, false, ctx
, hctx
);
1153 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1154 ctx
= alloc_data
.ctx
;
1155 hctx
= alloc_data
.hctx
;
1165 * Multiple hardware queue variant. This will not use per-process plugs,
1166 * but will attempt to bypass the hctx queueing if we can go straight to
1167 * hardware for SYNC IO.
1169 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1171 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1172 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1173 struct blk_map_ctx data
;
1176 blk_queue_bounce(q
, &bio
);
1178 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1179 bio_endio(bio
, -EIO
);
1183 rq
= blk_mq_map_request(q
, bio
, &data
);
1187 if (unlikely(is_flush_fua
)) {
1188 blk_mq_bio_to_request(rq
, bio
);
1189 blk_insert_flush(rq
);
1196 blk_mq_bio_to_request(rq
, bio
);
1197 blk_mq_start_request(rq
, true);
1200 * For OK queue, we are done. For error, kill it. Any other
1201 * error (busy), just add it to our list as we previously
1204 ret
= q
->mq_ops
->queue_rq(data
.hctx
, rq
);
1205 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1208 __blk_mq_requeue_request(rq
);
1210 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1212 blk_mq_end_io(rq
, rq
->errors
);
1218 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1220 * For a SYNC request, send it to the hardware immediately. For
1221 * an ASYNC request, just ensure that we run it later on. The
1222 * latter allows for merging opportunities and more efficient
1226 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1229 blk_mq_put_ctx(data
.ctx
);
1233 * Single hardware queue variant. This will attempt to use any per-process
1234 * plug for merging and IO deferral.
1236 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1238 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1239 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1240 unsigned int use_plug
, request_count
= 0;
1241 struct blk_map_ctx data
;
1245 * If we have multiple hardware queues, just go directly to
1246 * one of those for sync IO.
1248 use_plug
= !is_flush_fua
&& !is_sync
;
1250 blk_queue_bounce(q
, &bio
);
1252 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1253 bio_endio(bio
, -EIO
);
1257 if (use_plug
&& !blk_queue_nomerges(q
) &&
1258 blk_attempt_plug_merge(q
, bio
, &request_count
))
1261 rq
= blk_mq_map_request(q
, bio
, &data
);
1265 if (unlikely(is_flush_fua
)) {
1266 blk_mq_bio_to_request(rq
, bio
);
1267 blk_insert_flush(rq
);
1272 * A task plug currently exists. Since this is completely lockless,
1273 * utilize that to temporarily store requests until the task is
1274 * either done or scheduled away.
1277 struct blk_plug
*plug
= current
->plug
;
1280 blk_mq_bio_to_request(rq
, bio
);
1281 if (list_empty(&plug
->mq_list
))
1282 trace_block_plug(q
);
1283 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1284 blk_flush_plug_list(plug
, false);
1285 trace_block_plug(q
);
1287 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1288 blk_mq_put_ctx(data
.ctx
);
1293 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1295 * For a SYNC request, send it to the hardware immediately. For
1296 * an ASYNC request, just ensure that we run it later on. The
1297 * latter allows for merging opportunities and more efficient
1301 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1304 blk_mq_put_ctx(data
.ctx
);
1308 * Default mapping to a software queue, since we use one per CPU.
1310 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1312 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1314 EXPORT_SYMBOL(blk_mq_map_queue
);
1316 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1317 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1321 if (tags
->rqs
&& set
->ops
->exit_request
) {
1324 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1327 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1329 tags
->rqs
[i
] = NULL
;
1333 while (!list_empty(&tags
->page_list
)) {
1334 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1335 list_del_init(&page
->lru
);
1336 __free_pages(page
, page
->private);
1341 blk_mq_free_tags(tags
);
1344 static size_t order_to_size(unsigned int order
)
1346 return (size_t)PAGE_SIZE
<< order
;
1349 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1350 unsigned int hctx_idx
)
1352 struct blk_mq_tags
*tags
;
1353 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1354 size_t rq_size
, left
;
1356 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1361 INIT_LIST_HEAD(&tags
->page_list
);
1363 tags
->rqs
= kzalloc_node(set
->queue_depth
* sizeof(struct request
*),
1364 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1367 blk_mq_free_tags(tags
);
1372 * rq_size is the size of the request plus driver payload, rounded
1373 * to the cacheline size
1375 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1377 left
= rq_size
* set
->queue_depth
;
1379 for (i
= 0; i
< set
->queue_depth
; ) {
1380 int this_order
= max_order
;
1385 while (left
< order_to_size(this_order
- 1) && this_order
)
1389 page
= alloc_pages_node(set
->numa_node
,
1390 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1396 if (order_to_size(this_order
) < rq_size
)
1403 page
->private = this_order
;
1404 list_add_tail(&page
->lru
, &tags
->page_list
);
1406 p
= page_address(page
);
1407 entries_per_page
= order_to_size(this_order
) / rq_size
;
1408 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1409 left
-= to_do
* rq_size
;
1410 for (j
= 0; j
< to_do
; j
++) {
1412 tags
->rqs
[i
]->atomic_flags
= 0;
1413 tags
->rqs
[i
]->cmd_flags
= 0;
1414 if (set
->ops
->init_request
) {
1415 if (set
->ops
->init_request(set
->driver_data
,
1416 tags
->rqs
[i
], hctx_idx
, i
,
1418 tags
->rqs
[i
] = NULL
;
1431 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1435 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1440 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1442 unsigned int bpw
= 8, total
, num_maps
, i
;
1444 bitmap
->bits_per_word
= bpw
;
1446 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1447 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1452 bitmap
->map_size
= num_maps
;
1455 for (i
= 0; i
< num_maps
; i
++) {
1456 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1457 total
-= bitmap
->map
[i
].depth
;
1463 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1465 struct request_queue
*q
= hctx
->queue
;
1466 struct blk_mq_ctx
*ctx
;
1470 * Move ctx entries to new CPU, if this one is going away.
1472 ctx
= __blk_mq_get_ctx(q
, cpu
);
1474 spin_lock(&ctx
->lock
);
1475 if (!list_empty(&ctx
->rq_list
)) {
1476 list_splice_init(&ctx
->rq_list
, &tmp
);
1477 blk_mq_hctx_clear_pending(hctx
, ctx
);
1479 spin_unlock(&ctx
->lock
);
1481 if (list_empty(&tmp
))
1484 ctx
= blk_mq_get_ctx(q
);
1485 spin_lock(&ctx
->lock
);
1487 while (!list_empty(&tmp
)) {
1490 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1492 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1495 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1496 blk_mq_hctx_mark_pending(hctx
, ctx
);
1498 spin_unlock(&ctx
->lock
);
1500 blk_mq_run_hw_queue(hctx
, true);
1501 blk_mq_put_ctx(ctx
);
1505 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1507 struct request_queue
*q
= hctx
->queue
;
1508 struct blk_mq_tag_set
*set
= q
->tag_set
;
1510 if (set
->tags
[hctx
->queue_num
])
1513 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1514 if (!set
->tags
[hctx
->queue_num
])
1517 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1521 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1524 struct blk_mq_hw_ctx
*hctx
= data
;
1526 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1527 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1528 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1529 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1534 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1535 struct blk_mq_tag_set
*set
, int nr_queue
)
1537 struct blk_mq_hw_ctx
*hctx
;
1540 queue_for_each_hw_ctx(q
, hctx
, i
) {
1544 blk_mq_tag_idle(hctx
);
1546 if (set
->ops
->exit_hctx
)
1547 set
->ops
->exit_hctx(hctx
, i
);
1549 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1551 blk_mq_free_bitmap(&hctx
->ctx_map
);
1556 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1557 struct blk_mq_tag_set
*set
)
1559 struct blk_mq_hw_ctx
*hctx
;
1562 queue_for_each_hw_ctx(q
, hctx
, i
) {
1563 free_cpumask_var(hctx
->cpumask
);
1568 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1569 struct blk_mq_tag_set
*set
)
1571 struct blk_mq_hw_ctx
*hctx
;
1575 * Initialize hardware queues
1577 queue_for_each_hw_ctx(q
, hctx
, i
) {
1580 node
= hctx
->numa_node
;
1581 if (node
== NUMA_NO_NODE
)
1582 node
= hctx
->numa_node
= set
->numa_node
;
1584 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1585 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1586 spin_lock_init(&hctx
->lock
);
1587 INIT_LIST_HEAD(&hctx
->dispatch
);
1589 hctx
->queue_num
= i
;
1590 hctx
->flags
= set
->flags
;
1591 hctx
->cmd_size
= set
->cmd_size
;
1593 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1594 blk_mq_hctx_notify
, hctx
);
1595 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1597 hctx
->tags
= set
->tags
[i
];
1600 * Allocate space for all possible cpus to avoid allocation at
1603 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1608 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1613 if (set
->ops
->init_hctx
&&
1614 set
->ops
->init_hctx(hctx
, set
->driver_data
, i
))
1618 if (i
== q
->nr_hw_queues
)
1624 blk_mq_exit_hw_queues(q
, set
, i
);
1629 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1630 unsigned int nr_hw_queues
)
1634 for_each_possible_cpu(i
) {
1635 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1636 struct blk_mq_hw_ctx
*hctx
;
1638 memset(__ctx
, 0, sizeof(*__ctx
));
1640 spin_lock_init(&__ctx
->lock
);
1641 INIT_LIST_HEAD(&__ctx
->rq_list
);
1644 /* If the cpu isn't online, the cpu is mapped to first hctx */
1648 hctx
= q
->mq_ops
->map_queue(q
, i
);
1649 cpumask_set_cpu(i
, hctx
->cpumask
);
1653 * Set local node, IFF we have more than one hw queue. If
1654 * not, we remain on the home node of the device
1656 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1657 hctx
->numa_node
= cpu_to_node(i
);
1661 static void blk_mq_map_swqueue(struct request_queue
*q
)
1664 struct blk_mq_hw_ctx
*hctx
;
1665 struct blk_mq_ctx
*ctx
;
1667 queue_for_each_hw_ctx(q
, hctx
, i
) {
1668 cpumask_clear(hctx
->cpumask
);
1673 * Map software to hardware queues
1675 queue_for_each_ctx(q
, ctx
, i
) {
1676 /* If the cpu isn't online, the cpu is mapped to first hctx */
1680 hctx
= q
->mq_ops
->map_queue(q
, i
);
1681 cpumask_set_cpu(i
, hctx
->cpumask
);
1682 ctx
->index_hw
= hctx
->nr_ctx
;
1683 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1686 queue_for_each_hw_ctx(q
, hctx
, i
) {
1688 * If no software queues are mapped to this hardware queue,
1689 * disable it and free the request entries.
1691 if (!hctx
->nr_ctx
) {
1692 struct blk_mq_tag_set
*set
= q
->tag_set
;
1695 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1696 set
->tags
[i
] = NULL
;
1703 * Initialize batch roundrobin counts
1705 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1706 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1710 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1712 struct blk_mq_hw_ctx
*hctx
;
1713 struct request_queue
*q
;
1717 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1722 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1723 blk_mq_freeze_queue(q
);
1725 queue_for_each_hw_ctx(q
, hctx
, i
) {
1727 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1729 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1731 blk_mq_unfreeze_queue(q
);
1735 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1737 struct blk_mq_tag_set
*set
= q
->tag_set
;
1739 mutex_lock(&set
->tag_list_lock
);
1740 list_del_init(&q
->tag_set_list
);
1741 blk_mq_update_tag_set_depth(set
);
1742 mutex_unlock(&set
->tag_list_lock
);
1745 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1746 struct request_queue
*q
)
1750 mutex_lock(&set
->tag_list_lock
);
1751 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1752 blk_mq_update_tag_set_depth(set
);
1753 mutex_unlock(&set
->tag_list_lock
);
1756 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1758 struct blk_mq_hw_ctx
**hctxs
;
1759 struct blk_mq_ctx __percpu
*ctx
;
1760 struct request_queue
*q
;
1764 ctx
= alloc_percpu(struct blk_mq_ctx
);
1766 return ERR_PTR(-ENOMEM
);
1768 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1774 map
= blk_mq_make_queue_map(set
);
1778 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1779 int node
= blk_mq_hw_queue_to_node(map
, i
);
1781 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
1786 if (!zalloc_cpumask_var(&hctxs
[i
]->cpumask
, GFP_KERNEL
))
1789 atomic_set(&hctxs
[i
]->nr_active
, 0);
1790 hctxs
[i
]->numa_node
= node
;
1791 hctxs
[i
]->queue_num
= i
;
1794 q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1799 * Init percpu_ref in atomic mode so that it's faster to shutdown.
1800 * See blk_register_queue() for details.
1802 if (percpu_ref_init(&q
->mq_usage_counter
, blk_mq_usage_counter_release
,
1803 PERCPU_REF_INIT_ATOMIC
, GFP_KERNEL
))
1806 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1807 blk_queue_rq_timeout(q
, 30000);
1809 q
->nr_queues
= nr_cpu_ids
;
1810 q
->nr_hw_queues
= set
->nr_hw_queues
;
1814 q
->queue_hw_ctx
= hctxs
;
1816 q
->mq_ops
= set
->ops
;
1817 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1819 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
1820 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
1822 q
->sg_reserved_size
= INT_MAX
;
1824 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
1825 INIT_LIST_HEAD(&q
->requeue_list
);
1826 spin_lock_init(&q
->requeue_lock
);
1828 if (q
->nr_hw_queues
> 1)
1829 blk_queue_make_request(q
, blk_mq_make_request
);
1831 blk_queue_make_request(q
, blk_sq_make_request
);
1833 blk_queue_rq_timed_out(q
, blk_mq_rq_timed_out
);
1835 blk_queue_rq_timeout(q
, set
->timeout
);
1838 * Do this after blk_queue_make_request() overrides it...
1840 q
->nr_requests
= set
->queue_depth
;
1842 if (set
->ops
->complete
)
1843 blk_queue_softirq_done(q
, set
->ops
->complete
);
1845 blk_mq_init_flush(q
);
1846 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
1848 q
->flush_rq
= kzalloc(round_up(sizeof(struct request
) +
1849 set
->cmd_size
, cache_line_size()),
1854 if (blk_mq_init_hw_queues(q
, set
))
1857 mutex_lock(&all_q_mutex
);
1858 list_add_tail(&q
->all_q_node
, &all_q_list
);
1859 mutex_unlock(&all_q_mutex
);
1861 blk_mq_add_queue_tag_set(set
, q
);
1863 blk_mq_map_swqueue(q
);
1870 blk_cleanup_queue(q
);
1873 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1876 free_cpumask_var(hctxs
[i
]->cpumask
);
1883 return ERR_PTR(-ENOMEM
);
1885 EXPORT_SYMBOL(blk_mq_init_queue
);
1887 void blk_mq_free_queue(struct request_queue
*q
)
1889 struct blk_mq_tag_set
*set
= q
->tag_set
;
1891 blk_mq_del_queue_tag_set(q
);
1893 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1894 blk_mq_free_hw_queues(q
, set
);
1896 percpu_ref_exit(&q
->mq_usage_counter
);
1898 free_percpu(q
->queue_ctx
);
1899 kfree(q
->queue_hw_ctx
);
1902 q
->queue_ctx
= NULL
;
1903 q
->queue_hw_ctx
= NULL
;
1906 mutex_lock(&all_q_mutex
);
1907 list_del_init(&q
->all_q_node
);
1908 mutex_unlock(&all_q_mutex
);
1911 /* Basically redo blk_mq_init_queue with queue frozen */
1912 static void blk_mq_queue_reinit(struct request_queue
*q
)
1914 blk_mq_freeze_queue(q
);
1916 blk_mq_sysfs_unregister(q
);
1918 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1921 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1922 * we should change hctx numa_node according to new topology (this
1923 * involves free and re-allocate memory, worthy doing?)
1926 blk_mq_map_swqueue(q
);
1928 blk_mq_sysfs_register(q
);
1930 blk_mq_unfreeze_queue(q
);
1933 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1934 unsigned long action
, void *hcpu
)
1936 struct request_queue
*q
;
1939 * Before new mappings are established, hotadded cpu might already
1940 * start handling requests. This doesn't break anything as we map
1941 * offline CPUs to first hardware queue. We will re-init the queue
1942 * below to get optimal settings.
1944 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1945 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1948 mutex_lock(&all_q_mutex
);
1949 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1950 blk_mq_queue_reinit(q
);
1951 mutex_unlock(&all_q_mutex
);
1955 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
1959 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1960 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
1969 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1975 * Allocate the request maps associated with this tag_set. Note that this
1976 * may reduce the depth asked for, if memory is tight. set->queue_depth
1977 * will be updated to reflect the allocated depth.
1979 static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
1984 depth
= set
->queue_depth
;
1986 err
= __blk_mq_alloc_rq_maps(set
);
1990 set
->queue_depth
>>= 1;
1991 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
1995 } while (set
->queue_depth
);
1997 if (!set
->queue_depth
|| err
) {
1998 pr_err("blk-mq: failed to allocate request map\n");
2002 if (depth
!= set
->queue_depth
)
2003 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
2004 depth
, set
->queue_depth
);
2010 * Alloc a tag set to be associated with one or more request queues.
2011 * May fail with EINVAL for various error conditions. May adjust the
2012 * requested depth down, if if it too large. In that case, the set
2013 * value will be stored in set->queue_depth.
2015 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
2017 if (!set
->nr_hw_queues
)
2019 if (!set
->queue_depth
)
2021 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
2024 if (!set
->nr_hw_queues
|| !set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
2027 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
2028 pr_info("blk-mq: reduced tag depth to %u\n",
2030 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
2033 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
2034 sizeof(struct blk_mq_tags
*),
2035 GFP_KERNEL
, set
->numa_node
);
2039 if (blk_mq_alloc_rq_maps(set
))
2042 mutex_init(&set
->tag_list_lock
);
2043 INIT_LIST_HEAD(&set
->tag_list
);
2051 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2053 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2057 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2059 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2065 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2067 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2069 struct blk_mq_tag_set
*set
= q
->tag_set
;
2070 struct blk_mq_hw_ctx
*hctx
;
2073 if (!set
|| nr
> set
->queue_depth
)
2077 queue_for_each_hw_ctx(q
, hctx
, i
) {
2078 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2084 q
->nr_requests
= nr
;
2089 void blk_mq_disable_hotplug(void)
2091 mutex_lock(&all_q_mutex
);
2094 void blk_mq_enable_hotplug(void)
2096 mutex_unlock(&all_q_mutex
);
2099 static int __init
blk_mq_init(void)
2103 hotcpu_notifier(blk_mq_queue_reinit_notify
, 0);
2107 subsys_initcall(blk_mq_init
);