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
)
83 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
86 /* we have problems freezing the queue if it's initializing */
87 if (!blk_queue_dying(q
) &&
88 (!blk_queue_bypass(q
) || !blk_queue_init_done(q
)))
91 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
93 spin_lock_irq(q
->queue_lock
);
94 ret
= wait_event_interruptible_lock_irq(q
->mq_freeze_wq
,
95 !blk_queue_bypass(q
) || blk_queue_dying(q
),
97 /* inc usage with lock hold to avoid freeze_queue runs here */
98 if (!ret
&& !blk_queue_dying(q
))
99 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
100 else if (blk_queue_dying(q
))
102 spin_unlock_irq(q
->queue_lock
);
107 static void blk_mq_queue_exit(struct request_queue
*q
)
109 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
112 void blk_mq_drain_queue(struct request_queue
*q
)
117 spin_lock_irq(q
->queue_lock
);
118 count
= percpu_counter_sum(&q
->mq_usage_counter
);
119 spin_unlock_irq(q
->queue_lock
);
123 blk_mq_start_hw_queues(q
);
129 * Guarantee no request is in use, so we can change any data structure of
130 * the queue afterward.
132 static void blk_mq_freeze_queue(struct request_queue
*q
)
136 spin_lock_irq(q
->queue_lock
);
137 drain
= !q
->bypass_depth
++;
138 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
139 spin_unlock_irq(q
->queue_lock
);
142 blk_mq_drain_queue(q
);
145 static void blk_mq_unfreeze_queue(struct request_queue
*q
)
149 spin_lock_irq(q
->queue_lock
);
150 if (!--q
->bypass_depth
) {
151 queue_flag_clear(QUEUE_FLAG_BYPASS
, q
);
154 WARN_ON_ONCE(q
->bypass_depth
< 0);
155 spin_unlock_irq(q
->queue_lock
);
157 wake_up_all(&q
->mq_freeze_wq
);
160 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
162 return blk_mq_has_free_tags(hctx
->tags
);
164 EXPORT_SYMBOL(blk_mq_can_queue
);
166 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
167 struct request
*rq
, unsigned int rw_flags
)
169 if (blk_queue_io_stat(q
))
170 rw_flags
|= REQ_IO_STAT
;
172 INIT_LIST_HEAD(&rq
->queuelist
);
173 /* csd/requeue_work/fifo_time is initialized before use */
176 rq
->cmd_flags
|= rw_flags
;
177 /* do not touch atomic flags, it needs atomic ops against the timer */
179 INIT_HLIST_NODE(&rq
->hash
);
180 RB_CLEAR_NODE(&rq
->rb_node
);
183 rq
->start_time
= jiffies
;
184 #ifdef CONFIG_BLK_CGROUP
186 set_start_time_ns(rq
);
187 rq
->io_start_time_ns
= 0;
189 rq
->nr_phys_segments
= 0;
190 #if defined(CONFIG_BLK_DEV_INTEGRITY)
191 rq
->nr_integrity_segments
= 0;
194 /* tag was already set */
202 INIT_LIST_HEAD(&rq
->timeout_list
);
206 rq
->end_io_data
= NULL
;
209 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
212 static struct request
*
213 __blk_mq_alloc_request(struct blk_mq_alloc_data
*data
, int rw
)
218 tag
= blk_mq_get_tag(data
);
219 if (tag
!= BLK_MQ_TAG_FAIL
) {
220 rq
= data
->hctx
->tags
->rqs
[tag
];
223 if (blk_mq_tag_busy(data
->hctx
)) {
224 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
225 atomic_inc(&data
->hctx
->nr_active
);
229 blk_mq_rq_ctx_init(data
->q
, data
->ctx
, rq
, rw
);
236 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
,
239 struct blk_mq_ctx
*ctx
;
240 struct blk_mq_hw_ctx
*hctx
;
242 struct blk_mq_alloc_data alloc_data
;
244 if (blk_mq_queue_enter(q
))
247 ctx
= blk_mq_get_ctx(q
);
248 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
249 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
& ~__GFP_WAIT
,
250 reserved
, ctx
, hctx
);
252 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
253 if (!rq
&& (gfp
& __GFP_WAIT
)) {
254 __blk_mq_run_hw_queue(hctx
);
257 ctx
= blk_mq_get_ctx(q
);
258 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
259 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
, reserved
, ctx
,
261 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
262 ctx
= alloc_data
.ctx
;
267 EXPORT_SYMBOL(blk_mq_alloc_request
);
269 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
270 struct blk_mq_ctx
*ctx
, struct request
*rq
)
272 const int tag
= rq
->tag
;
273 struct request_queue
*q
= rq
->q
;
275 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
276 atomic_dec(&hctx
->nr_active
);
278 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
279 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
280 blk_mq_queue_exit(q
);
283 void blk_mq_free_request(struct request
*rq
)
285 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
286 struct blk_mq_hw_ctx
*hctx
;
287 struct request_queue
*q
= rq
->q
;
289 ctx
->rq_completed
[rq_is_sync(rq
)]++;
291 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
292 __blk_mq_free_request(hctx
, ctx
, rq
);
296 * Clone all relevant state from a request that has been put on hold in
297 * the flush state machine into the preallocated flush request that hangs
298 * off the request queue.
300 * For a driver the flush request should be invisible, that's why we are
301 * impersonating the original request here.
303 void blk_mq_clone_flush_request(struct request
*flush_rq
,
304 struct request
*orig_rq
)
306 struct blk_mq_hw_ctx
*hctx
=
307 orig_rq
->q
->mq_ops
->map_queue(orig_rq
->q
, orig_rq
->mq_ctx
->cpu
);
309 flush_rq
->mq_ctx
= orig_rq
->mq_ctx
;
310 flush_rq
->tag
= orig_rq
->tag
;
311 memcpy(blk_mq_rq_to_pdu(flush_rq
), blk_mq_rq_to_pdu(orig_rq
),
315 inline void __blk_mq_end_io(struct request
*rq
, int error
)
317 blk_account_io_done(rq
);
320 rq
->end_io(rq
, error
);
322 if (unlikely(blk_bidi_rq(rq
)))
323 blk_mq_free_request(rq
->next_rq
);
324 blk_mq_free_request(rq
);
327 EXPORT_SYMBOL(__blk_mq_end_io
);
329 void blk_mq_end_io(struct request
*rq
, int error
)
331 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
333 __blk_mq_end_io(rq
, error
);
335 EXPORT_SYMBOL(blk_mq_end_io
);
337 static void __blk_mq_complete_request_remote(void *data
)
339 struct request
*rq
= data
;
341 rq
->q
->softirq_done_fn(rq
);
344 static void blk_mq_ipi_complete_request(struct request
*rq
)
346 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
350 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
351 rq
->q
->softirq_done_fn(rq
);
356 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
357 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
359 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
360 rq
->csd
.func
= __blk_mq_complete_request_remote
;
363 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
365 rq
->q
->softirq_done_fn(rq
);
370 void __blk_mq_complete_request(struct request
*rq
)
372 struct request_queue
*q
= rq
->q
;
374 if (!q
->softirq_done_fn
)
375 blk_mq_end_io(rq
, rq
->errors
);
377 blk_mq_ipi_complete_request(rq
);
381 * blk_mq_complete_request - end I/O on a request
382 * @rq: the request being processed
385 * Ends all I/O on a request. It does not handle partial completions.
386 * The actual completion happens out-of-order, through a IPI handler.
388 void blk_mq_complete_request(struct request
*rq
)
390 struct request_queue
*q
= rq
->q
;
392 if (unlikely(blk_should_fake_timeout(q
)))
394 if (!blk_mark_rq_complete(rq
))
395 __blk_mq_complete_request(rq
);
397 EXPORT_SYMBOL(blk_mq_complete_request
);
399 static void blk_mq_start_request(struct request
*rq
, bool last
)
401 struct request_queue
*q
= rq
->q
;
403 trace_block_rq_issue(q
, rq
);
405 rq
->resid_len
= blk_rq_bytes(rq
);
406 if (unlikely(blk_bidi_rq(rq
)))
407 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
412 * Mark us as started and clear complete. Complete might have been
413 * set if requeue raced with timeout, which then marked it as
414 * complete. So be sure to clear complete again when we start
415 * the request, otherwise we'll ignore the completion event.
417 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
418 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
419 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
420 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
422 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
424 * Make sure space for the drain appears. We know we can do
425 * this because max_hw_segments has been adjusted to be one
426 * fewer than the device can handle.
428 rq
->nr_phys_segments
++;
432 * Flag the last request in the series so that drivers know when IO
433 * should be kicked off, if they don't do it on a per-request basis.
435 * Note: the flag isn't the only condition drivers should do kick off.
436 * If drive is busy, the last request might not have the bit set.
439 rq
->cmd_flags
|= REQ_END
;
442 static void __blk_mq_requeue_request(struct request
*rq
)
444 struct request_queue
*q
= rq
->q
;
446 trace_block_rq_requeue(q
, rq
);
447 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
449 rq
->cmd_flags
&= ~REQ_END
;
451 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
452 rq
->nr_phys_segments
--;
455 void blk_mq_requeue_request(struct request
*rq
)
457 __blk_mq_requeue_request(rq
);
458 blk_clear_rq_complete(rq
);
460 BUG_ON(blk_queued_rq(rq
));
461 blk_mq_add_to_requeue_list(rq
, true);
463 EXPORT_SYMBOL(blk_mq_requeue_request
);
465 static void blk_mq_requeue_work(struct work_struct
*work
)
467 struct request_queue
*q
=
468 container_of(work
, struct request_queue
, requeue_work
);
470 struct request
*rq
, *next
;
473 spin_lock_irqsave(&q
->requeue_lock
, flags
);
474 list_splice_init(&q
->requeue_list
, &rq_list
);
475 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
477 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
478 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
481 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
482 list_del_init(&rq
->queuelist
);
483 blk_mq_insert_request(rq
, true, false, false);
486 while (!list_empty(&rq_list
)) {
487 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
488 list_del_init(&rq
->queuelist
);
489 blk_mq_insert_request(rq
, false, false, false);
492 blk_mq_run_queues(q
, false);
495 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
497 struct request_queue
*q
= rq
->q
;
501 * We abuse this flag that is otherwise used by the I/O scheduler to
502 * request head insertation from the workqueue.
504 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
506 spin_lock_irqsave(&q
->requeue_lock
, flags
);
508 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
509 list_add(&rq
->queuelist
, &q
->requeue_list
);
511 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
513 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
515 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
517 void blk_mq_kick_requeue_list(struct request_queue
*q
)
519 kblockd_schedule_work(&q
->requeue_work
);
521 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
523 static inline bool is_flush_request(struct request
*rq
, unsigned int tag
)
525 return ((rq
->cmd_flags
& REQ_FLUSH_SEQ
) &&
526 rq
->q
->flush_rq
->tag
== tag
);
529 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
531 struct request
*rq
= tags
->rqs
[tag
];
533 if (!is_flush_request(rq
, tag
))
536 return rq
->q
->flush_rq
;
538 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
540 struct blk_mq_timeout_data
{
541 struct blk_mq_hw_ctx
*hctx
;
543 unsigned int *next_set
;
546 static void blk_mq_timeout_check(void *__data
, unsigned long *free_tags
)
548 struct blk_mq_timeout_data
*data
= __data
;
549 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
552 /* It may not be in flight yet (this is where
553 * the REQ_ATOMIC_STARTED flag comes in). The requests are
554 * statically allocated, so we know it's always safe to access the
555 * memory associated with a bit offset into ->rqs[].
561 tag
= find_next_zero_bit(free_tags
, hctx
->tags
->nr_tags
, tag
);
562 if (tag
>= hctx
->tags
->nr_tags
)
565 rq
= blk_mq_tag_to_rq(hctx
->tags
, tag
++);
566 if (rq
->q
!= hctx
->queue
)
568 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
571 blk_rq_check_expired(rq
, data
->next
, data
->next_set
);
575 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx
*hctx
,
577 unsigned int *next_set
)
579 struct blk_mq_timeout_data data
= {
582 .next_set
= next_set
,
586 * Ask the tagging code to iterate busy requests, so we can
587 * check them for timeout.
589 blk_mq_tag_busy_iter(hctx
->tags
, blk_mq_timeout_check
, &data
);
592 static enum blk_eh_timer_return
blk_mq_rq_timed_out(struct request
*rq
)
594 struct request_queue
*q
= rq
->q
;
597 * We know that complete is set at this point. If STARTED isn't set
598 * anymore, then the request isn't active and the "timeout" should
599 * just be ignored. This can happen due to the bitflag ordering.
600 * Timeout first checks if STARTED is set, and if it is, assumes
601 * the request is active. But if we race with completion, then
602 * we both flags will get cleared. So check here again, and ignore
603 * a timeout event with a request that isn't active.
605 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
606 return BLK_EH_NOT_HANDLED
;
608 if (!q
->mq_ops
->timeout
)
609 return BLK_EH_RESET_TIMER
;
611 return q
->mq_ops
->timeout(rq
);
614 static void blk_mq_rq_timer(unsigned long data
)
616 struct request_queue
*q
= (struct request_queue
*) data
;
617 struct blk_mq_hw_ctx
*hctx
;
618 unsigned long next
= 0;
621 queue_for_each_hw_ctx(q
, hctx
, i
) {
623 * If not software queues are currently mapped to this
624 * hardware queue, there's nothing to check
626 if (!hctx
->nr_ctx
|| !hctx
->tags
)
629 blk_mq_hw_ctx_check_timeout(hctx
, &next
, &next_set
);
633 next
= blk_rq_timeout(round_jiffies_up(next
));
634 mod_timer(&q
->timeout
, next
);
636 queue_for_each_hw_ctx(q
, hctx
, i
)
637 blk_mq_tag_idle(hctx
);
642 * Reverse check our software queue for entries that we could potentially
643 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
644 * too much time checking for merges.
646 static bool blk_mq_attempt_merge(struct request_queue
*q
,
647 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
652 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
658 if (!blk_rq_merge_ok(rq
, bio
))
661 el_ret
= blk_try_merge(rq
, bio
);
662 if (el_ret
== ELEVATOR_BACK_MERGE
) {
663 if (bio_attempt_back_merge(q
, rq
, bio
)) {
668 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
669 if (bio_attempt_front_merge(q
, rq
, bio
)) {
681 * Process software queues that have been marked busy, splicing them
682 * to the for-dispatch
684 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
686 struct blk_mq_ctx
*ctx
;
689 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++) {
690 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
691 unsigned int off
, bit
;
697 off
= i
* hctx
->ctx_map
.bits_per_word
;
699 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
700 if (bit
>= bm
->depth
)
703 ctx
= hctx
->ctxs
[bit
+ off
];
704 clear_bit(bit
, &bm
->word
);
705 spin_lock(&ctx
->lock
);
706 list_splice_tail_init(&ctx
->rq_list
, list
);
707 spin_unlock(&ctx
->lock
);
715 * Run this hardware queue, pulling any software queues mapped to it in.
716 * Note that this function currently has various problems around ordering
717 * of IO. In particular, we'd like FIFO behaviour on handling existing
718 * items on the hctx->dispatch list. Ignore that for now.
720 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
722 struct request_queue
*q
= hctx
->queue
;
727 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
729 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
735 * Touch any software queue that has pending entries.
737 flush_busy_ctxs(hctx
, &rq_list
);
740 * If we have previous entries on our dispatch list, grab them
741 * and stuff them at the front for more fair dispatch.
743 if (!list_empty_careful(&hctx
->dispatch
)) {
744 spin_lock(&hctx
->lock
);
745 if (!list_empty(&hctx
->dispatch
))
746 list_splice_init(&hctx
->dispatch
, &rq_list
);
747 spin_unlock(&hctx
->lock
);
751 * Now process all the entries, sending them to the driver.
754 while (!list_empty(&rq_list
)) {
757 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
758 list_del_init(&rq
->queuelist
);
760 blk_mq_start_request(rq
, list_empty(&rq_list
));
762 ret
= q
->mq_ops
->queue_rq(hctx
, rq
);
764 case BLK_MQ_RQ_QUEUE_OK
:
767 case BLK_MQ_RQ_QUEUE_BUSY
:
768 list_add(&rq
->queuelist
, &rq_list
);
769 __blk_mq_requeue_request(rq
);
772 pr_err("blk-mq: bad return on queue: %d\n", ret
);
773 case BLK_MQ_RQ_QUEUE_ERROR
:
775 blk_mq_end_io(rq
, rq
->errors
);
779 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
784 hctx
->dispatched
[0]++;
785 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
786 hctx
->dispatched
[ilog2(queued
) + 1]++;
789 * Any items that need requeuing? Stuff them into hctx->dispatch,
790 * that is where we will continue on next queue run.
792 if (!list_empty(&rq_list
)) {
793 spin_lock(&hctx
->lock
);
794 list_splice(&rq_list
, &hctx
->dispatch
);
795 spin_unlock(&hctx
->lock
);
800 * It'd be great if the workqueue API had a way to pass
801 * in a mask and had some smarts for more clever placement.
802 * For now we just round-robin here, switching for every
803 * BLK_MQ_CPU_WORK_BATCH queued items.
805 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
807 int cpu
= hctx
->next_cpu
;
809 if (--hctx
->next_cpu_batch
<= 0) {
812 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
813 if (next_cpu
>= nr_cpu_ids
)
814 next_cpu
= cpumask_first(hctx
->cpumask
);
816 hctx
->next_cpu
= next_cpu
;
817 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
823 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
825 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
828 if (!async
&& cpumask_test_cpu(smp_processor_id(), hctx
->cpumask
))
829 __blk_mq_run_hw_queue(hctx
);
830 else if (hctx
->queue
->nr_hw_queues
== 1)
831 kblockd_schedule_delayed_work(&hctx
->run_work
, 0);
835 cpu
= blk_mq_hctx_next_cpu(hctx
);
836 kblockd_schedule_delayed_work_on(cpu
, &hctx
->run_work
, 0);
840 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
842 struct blk_mq_hw_ctx
*hctx
;
845 queue_for_each_hw_ctx(q
, hctx
, i
) {
846 if ((!blk_mq_hctx_has_pending(hctx
) &&
847 list_empty_careful(&hctx
->dispatch
)) ||
848 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
852 blk_mq_run_hw_queue(hctx
, async
);
856 EXPORT_SYMBOL(blk_mq_run_queues
);
858 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
860 cancel_delayed_work(&hctx
->run_work
);
861 cancel_delayed_work(&hctx
->delay_work
);
862 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
864 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
866 void blk_mq_stop_hw_queues(struct request_queue
*q
)
868 struct blk_mq_hw_ctx
*hctx
;
871 queue_for_each_hw_ctx(q
, hctx
, i
)
872 blk_mq_stop_hw_queue(hctx
);
874 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
876 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
878 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
881 blk_mq_run_hw_queue(hctx
, false);
884 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
886 void blk_mq_start_hw_queues(struct request_queue
*q
)
888 struct blk_mq_hw_ctx
*hctx
;
891 queue_for_each_hw_ctx(q
, hctx
, i
)
892 blk_mq_start_hw_queue(hctx
);
894 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
897 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
899 struct blk_mq_hw_ctx
*hctx
;
902 queue_for_each_hw_ctx(q
, hctx
, i
) {
903 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
906 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
908 blk_mq_run_hw_queue(hctx
, async
);
912 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
914 static void blk_mq_run_work_fn(struct work_struct
*work
)
916 struct blk_mq_hw_ctx
*hctx
;
918 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
920 __blk_mq_run_hw_queue(hctx
);
923 static void blk_mq_delay_work_fn(struct work_struct
*work
)
925 struct blk_mq_hw_ctx
*hctx
;
927 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
929 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
930 __blk_mq_run_hw_queue(hctx
);
933 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
935 unsigned long tmo
= msecs_to_jiffies(msecs
);
937 if (hctx
->queue
->nr_hw_queues
== 1)
938 kblockd_schedule_delayed_work(&hctx
->delay_work
, tmo
);
942 cpu
= blk_mq_hctx_next_cpu(hctx
);
943 kblockd_schedule_delayed_work_on(cpu
, &hctx
->delay_work
, tmo
);
946 EXPORT_SYMBOL(blk_mq_delay_queue
);
948 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
949 struct request
*rq
, bool at_head
)
951 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
953 trace_block_rq_insert(hctx
->queue
, rq
);
956 list_add(&rq
->queuelist
, &ctx
->rq_list
);
958 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
960 blk_mq_hctx_mark_pending(hctx
, ctx
);
963 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
966 struct request_queue
*q
= rq
->q
;
967 struct blk_mq_hw_ctx
*hctx
;
968 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
970 current_ctx
= blk_mq_get_ctx(q
);
971 if (!cpu_online(ctx
->cpu
))
972 rq
->mq_ctx
= ctx
= current_ctx
;
974 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
976 if (rq
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
) &&
977 !(rq
->cmd_flags
& (REQ_FLUSH_SEQ
))) {
978 blk_insert_flush(rq
);
980 spin_lock(&ctx
->lock
);
981 __blk_mq_insert_request(hctx
, rq
, at_head
);
982 spin_unlock(&ctx
->lock
);
986 blk_mq_run_hw_queue(hctx
, async
);
988 blk_mq_put_ctx(current_ctx
);
991 static void blk_mq_insert_requests(struct request_queue
*q
,
992 struct blk_mq_ctx
*ctx
,
993 struct list_head
*list
,
998 struct blk_mq_hw_ctx
*hctx
;
999 struct blk_mq_ctx
*current_ctx
;
1001 trace_block_unplug(q
, depth
, !from_schedule
);
1003 current_ctx
= blk_mq_get_ctx(q
);
1005 if (!cpu_online(ctx
->cpu
))
1007 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1010 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1013 spin_lock(&ctx
->lock
);
1014 while (!list_empty(list
)) {
1017 rq
= list_first_entry(list
, struct request
, queuelist
);
1018 list_del_init(&rq
->queuelist
);
1020 __blk_mq_insert_request(hctx
, rq
, false);
1022 spin_unlock(&ctx
->lock
);
1024 blk_mq_run_hw_queue(hctx
, from_schedule
);
1025 blk_mq_put_ctx(current_ctx
);
1028 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1030 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1031 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1033 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1034 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1035 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1038 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1040 struct blk_mq_ctx
*this_ctx
;
1041 struct request_queue
*this_q
;
1044 LIST_HEAD(ctx_list
);
1047 list_splice_init(&plug
->mq_list
, &list
);
1049 list_sort(NULL
, &list
, plug_ctx_cmp
);
1055 while (!list_empty(&list
)) {
1056 rq
= list_entry_rq(list
.next
);
1057 list_del_init(&rq
->queuelist
);
1059 if (rq
->mq_ctx
!= this_ctx
) {
1061 blk_mq_insert_requests(this_q
, this_ctx
,
1066 this_ctx
= rq
->mq_ctx
;
1072 list_add_tail(&rq
->queuelist
, &ctx_list
);
1076 * If 'this_ctx' is set, we know we have entries to complete
1077 * on 'ctx_list'. Do those.
1080 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1085 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1087 init_request_from_bio(rq
, bio
);
1089 if (blk_do_io_stat(rq
))
1090 blk_account_io_start(rq
, 1);
1093 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1094 struct blk_mq_ctx
*ctx
,
1095 struct request
*rq
, struct bio
*bio
)
1097 struct request_queue
*q
= hctx
->queue
;
1099 if (!(hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
)) {
1100 blk_mq_bio_to_request(rq
, bio
);
1101 spin_lock(&ctx
->lock
);
1103 __blk_mq_insert_request(hctx
, rq
, false);
1104 spin_unlock(&ctx
->lock
);
1107 spin_lock(&ctx
->lock
);
1108 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1109 blk_mq_bio_to_request(rq
, bio
);
1113 spin_unlock(&ctx
->lock
);
1114 __blk_mq_free_request(hctx
, ctx
, rq
);
1119 struct blk_map_ctx
{
1120 struct blk_mq_hw_ctx
*hctx
;
1121 struct blk_mq_ctx
*ctx
;
1124 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1126 struct blk_map_ctx
*data
)
1128 struct blk_mq_hw_ctx
*hctx
;
1129 struct blk_mq_ctx
*ctx
;
1131 int rw
= bio_data_dir(bio
);
1132 struct blk_mq_alloc_data alloc_data
;
1134 if (unlikely(blk_mq_queue_enter(q
))) {
1135 bio_endio(bio
, -EIO
);
1139 ctx
= blk_mq_get_ctx(q
);
1140 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1142 if (rw_is_sync(bio
->bi_rw
))
1145 trace_block_getrq(q
, bio
, rw
);
1146 blk_mq_set_alloc_data(&alloc_data
, q
, GFP_ATOMIC
, false, ctx
,
1148 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1149 if (unlikely(!rq
)) {
1150 __blk_mq_run_hw_queue(hctx
);
1151 blk_mq_put_ctx(ctx
);
1152 trace_block_sleeprq(q
, bio
, rw
);
1154 ctx
= blk_mq_get_ctx(q
);
1155 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1156 blk_mq_set_alloc_data(&alloc_data
, q
,
1157 __GFP_WAIT
|GFP_ATOMIC
, false, ctx
, hctx
);
1158 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1159 ctx
= alloc_data
.ctx
;
1160 hctx
= alloc_data
.hctx
;
1170 * Multiple hardware queue variant. This will not use per-process plugs,
1171 * but will attempt to bypass the hctx queueing if we can go straight to
1172 * hardware for SYNC IO.
1174 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1176 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1177 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1178 struct blk_map_ctx data
;
1181 blk_queue_bounce(q
, &bio
);
1183 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1184 bio_endio(bio
, -EIO
);
1188 rq
= blk_mq_map_request(q
, bio
, &data
);
1192 if (unlikely(is_flush_fua
)) {
1193 blk_mq_bio_to_request(rq
, bio
);
1194 blk_insert_flush(rq
);
1201 blk_mq_bio_to_request(rq
, bio
);
1202 blk_mq_start_request(rq
, true);
1205 * For OK queue, we are done. For error, kill it. Any other
1206 * error (busy), just add it to our list as we previously
1209 ret
= q
->mq_ops
->queue_rq(data
.hctx
, rq
);
1210 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1213 __blk_mq_requeue_request(rq
);
1215 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1217 blk_mq_end_io(rq
, rq
->errors
);
1223 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1225 * For a SYNC request, send it to the hardware immediately. For
1226 * an ASYNC request, just ensure that we run it later on. The
1227 * latter allows for merging opportunities and more efficient
1231 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1234 blk_mq_put_ctx(data
.ctx
);
1238 * Single hardware queue variant. This will attempt to use any per-process
1239 * plug for merging and IO deferral.
1241 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1243 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1244 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1245 unsigned int use_plug
, request_count
= 0;
1246 struct blk_map_ctx data
;
1250 * If we have multiple hardware queues, just go directly to
1251 * one of those for sync IO.
1253 use_plug
= !is_flush_fua
&& !is_sync
;
1255 blk_queue_bounce(q
, &bio
);
1257 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1258 bio_endio(bio
, -EIO
);
1262 if (use_plug
&& !blk_queue_nomerges(q
) &&
1263 blk_attempt_plug_merge(q
, bio
, &request_count
))
1266 rq
= blk_mq_map_request(q
, bio
, &data
);
1270 if (unlikely(is_flush_fua
)) {
1271 blk_mq_bio_to_request(rq
, bio
);
1272 blk_insert_flush(rq
);
1277 * A task plug currently exists. Since this is completely lockless,
1278 * utilize that to temporarily store requests until the task is
1279 * either done or scheduled away.
1282 struct blk_plug
*plug
= current
->plug
;
1285 blk_mq_bio_to_request(rq
, bio
);
1286 if (list_empty(&plug
->mq_list
))
1287 trace_block_plug(q
);
1288 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1289 blk_flush_plug_list(plug
, false);
1290 trace_block_plug(q
);
1292 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1293 blk_mq_put_ctx(data
.ctx
);
1298 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1300 * For a SYNC request, send it to the hardware immediately. For
1301 * an ASYNC request, just ensure that we run it later on. The
1302 * latter allows for merging opportunities and more efficient
1306 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1309 blk_mq_put_ctx(data
.ctx
);
1313 * Default mapping to a software queue, since we use one per CPU.
1315 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1317 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1319 EXPORT_SYMBOL(blk_mq_map_queue
);
1321 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1322 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1326 if (tags
->rqs
&& set
->ops
->exit_request
) {
1329 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1332 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1337 while (!list_empty(&tags
->page_list
)) {
1338 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1339 list_del_init(&page
->lru
);
1340 __free_pages(page
, page
->private);
1345 blk_mq_free_tags(tags
);
1348 static size_t order_to_size(unsigned int order
)
1350 return (size_t)PAGE_SIZE
<< order
;
1353 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1354 unsigned int hctx_idx
)
1356 struct blk_mq_tags
*tags
;
1357 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1358 size_t rq_size
, left
;
1360 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1365 INIT_LIST_HEAD(&tags
->page_list
);
1367 tags
->rqs
= kmalloc_node(set
->queue_depth
* sizeof(struct request
*),
1368 GFP_KERNEL
, set
->numa_node
);
1370 blk_mq_free_tags(tags
);
1375 * rq_size is the size of the request plus driver payload, rounded
1376 * to the cacheline size
1378 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1380 left
= rq_size
* set
->queue_depth
;
1382 for (i
= 0; i
< set
->queue_depth
; ) {
1383 int this_order
= max_order
;
1388 while (left
< order_to_size(this_order
- 1) && this_order
)
1392 page
= alloc_pages_node(set
->numa_node
, GFP_KERNEL
,
1398 if (order_to_size(this_order
) < rq_size
)
1405 page
->private = this_order
;
1406 list_add_tail(&page
->lru
, &tags
->page_list
);
1408 p
= page_address(page
);
1409 entries_per_page
= order_to_size(this_order
) / rq_size
;
1410 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1411 left
-= to_do
* rq_size
;
1412 for (j
= 0; j
< to_do
; j
++) {
1414 if (set
->ops
->init_request
) {
1415 if (set
->ops
->init_request(set
->driver_data
,
1416 tags
->rqs
[i
], hctx_idx
, i
,
1429 pr_warn("%s: failed to allocate requests\n", __func__
);
1430 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1434 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1439 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1441 unsigned int bpw
= 8, total
, num_maps
, i
;
1443 bitmap
->bits_per_word
= bpw
;
1445 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1446 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1451 bitmap
->map_size
= num_maps
;
1454 for (i
= 0; i
< num_maps
; i
++) {
1455 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1456 total
-= bitmap
->map
[i
].depth
;
1462 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1464 struct request_queue
*q
= hctx
->queue
;
1465 struct blk_mq_ctx
*ctx
;
1469 * Move ctx entries to new CPU, if this one is going away.
1471 ctx
= __blk_mq_get_ctx(q
, cpu
);
1473 spin_lock(&ctx
->lock
);
1474 if (!list_empty(&ctx
->rq_list
)) {
1475 list_splice_init(&ctx
->rq_list
, &tmp
);
1476 blk_mq_hctx_clear_pending(hctx
, ctx
);
1478 spin_unlock(&ctx
->lock
);
1480 if (list_empty(&tmp
))
1483 ctx
= blk_mq_get_ctx(q
);
1484 spin_lock(&ctx
->lock
);
1486 while (!list_empty(&tmp
)) {
1489 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1491 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1494 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1495 blk_mq_hctx_mark_pending(hctx
, ctx
);
1497 spin_unlock(&ctx
->lock
);
1499 blk_mq_run_hw_queue(hctx
, true);
1500 blk_mq_put_ctx(ctx
);
1504 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1506 struct request_queue
*q
= hctx
->queue
;
1507 struct blk_mq_tag_set
*set
= q
->tag_set
;
1509 if (set
->tags
[hctx
->queue_num
])
1512 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1513 if (!set
->tags
[hctx
->queue_num
])
1516 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1520 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1523 struct blk_mq_hw_ctx
*hctx
= data
;
1525 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1526 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1527 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1528 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1533 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1534 struct blk_mq_tag_set
*set
, int nr_queue
)
1536 struct blk_mq_hw_ctx
*hctx
;
1539 queue_for_each_hw_ctx(q
, hctx
, i
) {
1543 blk_mq_tag_idle(hctx
);
1545 if (set
->ops
->exit_hctx
)
1546 set
->ops
->exit_hctx(hctx
, i
);
1548 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1550 blk_mq_free_bitmap(&hctx
->ctx_map
);
1555 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1556 struct blk_mq_tag_set
*set
)
1558 struct blk_mq_hw_ctx
*hctx
;
1561 queue_for_each_hw_ctx(q
, hctx
, i
) {
1562 free_cpumask_var(hctx
->cpumask
);
1567 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1568 struct blk_mq_tag_set
*set
)
1570 struct blk_mq_hw_ctx
*hctx
;
1574 * Initialize hardware queues
1576 queue_for_each_hw_ctx(q
, hctx
, i
) {
1579 node
= hctx
->numa_node
;
1580 if (node
== NUMA_NO_NODE
)
1581 node
= hctx
->numa_node
= set
->numa_node
;
1583 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1584 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1585 spin_lock_init(&hctx
->lock
);
1586 INIT_LIST_HEAD(&hctx
->dispatch
);
1588 hctx
->queue_num
= i
;
1589 hctx
->flags
= set
->flags
;
1590 hctx
->cmd_size
= set
->cmd_size
;
1592 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1593 blk_mq_hctx_notify
, hctx
);
1594 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1596 hctx
->tags
= set
->tags
[i
];
1599 * Allocate space for all possible cpus to avoid allocation in
1602 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1607 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1612 if (set
->ops
->init_hctx
&&
1613 set
->ops
->init_hctx(hctx
, set
->driver_data
, i
))
1617 if (i
== q
->nr_hw_queues
)
1623 blk_mq_exit_hw_queues(q
, set
, i
);
1628 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1629 unsigned int nr_hw_queues
)
1633 for_each_possible_cpu(i
) {
1634 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1635 struct blk_mq_hw_ctx
*hctx
;
1637 memset(__ctx
, 0, sizeof(*__ctx
));
1639 spin_lock_init(&__ctx
->lock
);
1640 INIT_LIST_HEAD(&__ctx
->rq_list
);
1643 /* If the cpu isn't online, the cpu is mapped to first hctx */
1647 hctx
= q
->mq_ops
->map_queue(q
, i
);
1648 cpumask_set_cpu(i
, hctx
->cpumask
);
1652 * Set local node, IFF we have more than one hw queue. If
1653 * not, we remain on the home node of the device
1655 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1656 hctx
->numa_node
= cpu_to_node(i
);
1660 static void blk_mq_map_swqueue(struct request_queue
*q
)
1663 struct blk_mq_hw_ctx
*hctx
;
1664 struct blk_mq_ctx
*ctx
;
1666 queue_for_each_hw_ctx(q
, hctx
, i
) {
1667 cpumask_clear(hctx
->cpumask
);
1672 * Map software to hardware queues
1674 queue_for_each_ctx(q
, ctx
, i
) {
1675 /* If the cpu isn't online, the cpu is mapped to first hctx */
1679 hctx
= q
->mq_ops
->map_queue(q
, i
);
1680 cpumask_set_cpu(i
, hctx
->cpumask
);
1681 ctx
->index_hw
= hctx
->nr_ctx
;
1682 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1685 queue_for_each_hw_ctx(q
, hctx
, i
) {
1687 * If not software queues are mapped to this hardware queue,
1688 * disable it and free the request entries
1690 if (!hctx
->nr_ctx
) {
1691 struct blk_mq_tag_set
*set
= q
->tag_set
;
1694 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1695 set
->tags
[i
] = NULL
;
1702 * Initialize batch roundrobin counts
1704 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1705 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1709 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1711 struct blk_mq_hw_ctx
*hctx
;
1712 struct request_queue
*q
;
1716 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1721 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1722 blk_mq_freeze_queue(q
);
1724 queue_for_each_hw_ctx(q
, hctx
, i
) {
1726 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1728 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1730 blk_mq_unfreeze_queue(q
);
1734 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1736 struct blk_mq_tag_set
*set
= q
->tag_set
;
1738 blk_mq_freeze_queue(q
);
1740 mutex_lock(&set
->tag_list_lock
);
1741 list_del_init(&q
->tag_set_list
);
1742 blk_mq_update_tag_set_depth(set
);
1743 mutex_unlock(&set
->tag_list_lock
);
1745 blk_mq_unfreeze_queue(q
);
1748 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1749 struct request_queue
*q
)
1753 mutex_lock(&set
->tag_list_lock
);
1754 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1755 blk_mq_update_tag_set_depth(set
);
1756 mutex_unlock(&set
->tag_list_lock
);
1759 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1761 struct blk_mq_hw_ctx
**hctxs
;
1762 struct blk_mq_ctx __percpu
*ctx
;
1763 struct request_queue
*q
;
1767 ctx
= alloc_percpu(struct blk_mq_ctx
);
1769 return ERR_PTR(-ENOMEM
);
1771 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1777 map
= blk_mq_make_queue_map(set
);
1781 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1782 int node
= blk_mq_hw_queue_to_node(map
, i
);
1784 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
1789 if (!zalloc_cpumask_var(&hctxs
[i
]->cpumask
, GFP_KERNEL
))
1792 atomic_set(&hctxs
[i
]->nr_active
, 0);
1793 hctxs
[i
]->numa_node
= node
;
1794 hctxs
[i
]->queue_num
= i
;
1797 q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1801 if (percpu_counter_init(&q
->mq_usage_counter
, 0))
1804 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1805 blk_queue_rq_timeout(q
, 30000);
1807 q
->nr_queues
= nr_cpu_ids
;
1808 q
->nr_hw_queues
= set
->nr_hw_queues
;
1812 q
->queue_hw_ctx
= hctxs
;
1814 q
->mq_ops
= set
->ops
;
1815 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1817 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
1818 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
1820 q
->sg_reserved_size
= INT_MAX
;
1822 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
1823 INIT_LIST_HEAD(&q
->requeue_list
);
1824 spin_lock_init(&q
->requeue_lock
);
1826 if (q
->nr_hw_queues
> 1)
1827 blk_queue_make_request(q
, blk_mq_make_request
);
1829 blk_queue_make_request(q
, blk_sq_make_request
);
1831 blk_queue_rq_timed_out(q
, blk_mq_rq_timed_out
);
1833 blk_queue_rq_timeout(q
, set
->timeout
);
1836 * Do this after blk_queue_make_request() overrides it...
1838 q
->nr_requests
= set
->queue_depth
;
1840 if (set
->ops
->complete
)
1841 blk_queue_softirq_done(q
, set
->ops
->complete
);
1843 blk_mq_init_flush(q
);
1844 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
1846 q
->flush_rq
= kzalloc(round_up(sizeof(struct request
) +
1847 set
->cmd_size
, cache_line_size()),
1852 if (blk_mq_init_hw_queues(q
, set
))
1855 mutex_lock(&all_q_mutex
);
1856 list_add_tail(&q
->all_q_node
, &all_q_list
);
1857 mutex_unlock(&all_q_mutex
);
1859 blk_mq_add_queue_tag_set(set
, q
);
1861 blk_mq_map_swqueue(q
);
1868 blk_cleanup_queue(q
);
1871 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1874 free_cpumask_var(hctxs
[i
]->cpumask
);
1881 return ERR_PTR(-ENOMEM
);
1883 EXPORT_SYMBOL(blk_mq_init_queue
);
1885 void blk_mq_free_queue(struct request_queue
*q
)
1887 struct blk_mq_tag_set
*set
= q
->tag_set
;
1889 blk_mq_del_queue_tag_set(q
);
1891 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1892 blk_mq_free_hw_queues(q
, set
);
1894 percpu_counter_destroy(&q
->mq_usage_counter
);
1896 free_percpu(q
->queue_ctx
);
1897 kfree(q
->queue_hw_ctx
);
1900 q
->queue_ctx
= NULL
;
1901 q
->queue_hw_ctx
= NULL
;
1904 mutex_lock(&all_q_mutex
);
1905 list_del_init(&q
->all_q_node
);
1906 mutex_unlock(&all_q_mutex
);
1909 /* Basically redo blk_mq_init_queue with queue frozen */
1910 static void blk_mq_queue_reinit(struct request_queue
*q
)
1912 blk_mq_freeze_queue(q
);
1914 blk_mq_sysfs_unregister(q
);
1916 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1919 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1920 * we should change hctx numa_node according to new topology (this
1921 * involves free and re-allocate memory, worthy doing?)
1924 blk_mq_map_swqueue(q
);
1926 blk_mq_sysfs_register(q
);
1928 blk_mq_unfreeze_queue(q
);
1931 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1932 unsigned long action
, void *hcpu
)
1934 struct request_queue
*q
;
1937 * Before new mappings are established, hotadded cpu might already
1938 * start handling requests. This doesn't break anything as we map
1939 * offline CPUs to first hardware queue. We will re-init the queue
1940 * below to get optimal settings.
1942 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1943 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1946 mutex_lock(&all_q_mutex
);
1947 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1948 blk_mq_queue_reinit(q
);
1949 mutex_unlock(&all_q_mutex
);
1954 * Alloc a tag set to be associated with one or more request queues.
1955 * May fail with EINVAL for various error conditions. May adjust the
1956 * requested depth down, if if it too large. In that case, the set
1957 * value will be stored in set->queue_depth.
1959 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
1963 if (!set
->nr_hw_queues
)
1965 if (!set
->queue_depth
)
1967 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
1970 if (!set
->nr_hw_queues
|| !set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
1973 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
1974 pr_info("blk-mq: reduced tag depth to %u\n",
1976 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
1979 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
1980 sizeof(struct blk_mq_tags
*),
1981 GFP_KERNEL
, set
->numa_node
);
1985 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1986 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
1991 mutex_init(&set
->tag_list_lock
);
1992 INIT_LIST_HEAD(&set
->tag_list
);
1998 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2002 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2004 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2008 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2010 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2015 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2017 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2019 struct blk_mq_tag_set
*set
= q
->tag_set
;
2020 struct blk_mq_hw_ctx
*hctx
;
2023 if (!set
|| nr
> set
->queue_depth
)
2027 queue_for_each_hw_ctx(q
, hctx
, i
) {
2028 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2034 q
->nr_requests
= nr
;
2039 void blk_mq_disable_hotplug(void)
2041 mutex_lock(&all_q_mutex
);
2044 void blk_mq_enable_hotplug(void)
2046 mutex_unlock(&all_q_mutex
);
2049 static int __init
blk_mq_init(void)
2053 /* Must be called after percpu_counter_hotcpu_callback() */
2054 hotcpu_notifier(blk_mq_queue_reinit_notify
, -10);
2058 subsys_initcall(blk_mq_init
);