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
;
228 ret
= blk_mq_queue_enter(q
);
232 ctx
= blk_mq_get_ctx(q
);
233 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
234 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
& ~__GFP_WAIT
,
235 reserved
, ctx
, hctx
);
237 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
238 if (!rq
&& (gfp
& __GFP_WAIT
)) {
239 __blk_mq_run_hw_queue(hctx
);
242 ctx
= blk_mq_get_ctx(q
);
243 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
244 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
, reserved
, ctx
,
246 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
247 ctx
= alloc_data
.ctx
;
251 return ERR_PTR(-EWOULDBLOCK
);
254 EXPORT_SYMBOL(blk_mq_alloc_request
);
256 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
257 struct blk_mq_ctx
*ctx
, struct request
*rq
)
259 const int tag
= rq
->tag
;
260 struct request_queue
*q
= rq
->q
;
262 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
263 atomic_dec(&hctx
->nr_active
);
266 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
267 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
268 blk_mq_queue_exit(q
);
271 void blk_mq_free_request(struct request
*rq
)
273 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
274 struct blk_mq_hw_ctx
*hctx
;
275 struct request_queue
*q
= rq
->q
;
277 ctx
->rq_completed
[rq_is_sync(rq
)]++;
279 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
280 __blk_mq_free_request(hctx
, ctx
, rq
);
284 * Clone all relevant state from a request that has been put on hold in
285 * the flush state machine into the preallocated flush request that hangs
286 * off the request queue.
288 * For a driver the flush request should be invisible, that's why we are
289 * impersonating the original request here.
291 void blk_mq_clone_flush_request(struct request
*flush_rq
,
292 struct request
*orig_rq
)
294 struct blk_mq_hw_ctx
*hctx
=
295 orig_rq
->q
->mq_ops
->map_queue(orig_rq
->q
, orig_rq
->mq_ctx
->cpu
);
297 flush_rq
->mq_ctx
= orig_rq
->mq_ctx
;
298 flush_rq
->tag
= orig_rq
->tag
;
299 memcpy(blk_mq_rq_to_pdu(flush_rq
), blk_mq_rq_to_pdu(orig_rq
),
303 inline void __blk_mq_end_request(struct request
*rq
, int error
)
305 blk_account_io_done(rq
);
308 rq
->end_io(rq
, error
);
310 if (unlikely(blk_bidi_rq(rq
)))
311 blk_mq_free_request(rq
->next_rq
);
312 blk_mq_free_request(rq
);
315 EXPORT_SYMBOL(__blk_mq_end_request
);
317 void blk_mq_end_request(struct request
*rq
, int error
)
319 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
321 __blk_mq_end_request(rq
, error
);
323 EXPORT_SYMBOL(blk_mq_end_request
);
325 static void __blk_mq_complete_request_remote(void *data
)
327 struct request
*rq
= data
;
329 rq
->q
->softirq_done_fn(rq
);
332 static void blk_mq_ipi_complete_request(struct request
*rq
)
334 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
338 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
339 rq
->q
->softirq_done_fn(rq
);
344 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
345 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
347 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
348 rq
->csd
.func
= __blk_mq_complete_request_remote
;
351 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
353 rq
->q
->softirq_done_fn(rq
);
358 void __blk_mq_complete_request(struct request
*rq
)
360 struct request_queue
*q
= rq
->q
;
362 if (!q
->softirq_done_fn
)
363 blk_mq_end_request(rq
, rq
->errors
);
365 blk_mq_ipi_complete_request(rq
);
369 * blk_mq_complete_request - end I/O on a request
370 * @rq: the request being processed
373 * Ends all I/O on a request. It does not handle partial completions.
374 * The actual completion happens out-of-order, through a IPI handler.
376 void blk_mq_complete_request(struct request
*rq
)
378 struct request_queue
*q
= rq
->q
;
380 if (unlikely(blk_should_fake_timeout(q
)))
382 if (!blk_mark_rq_complete(rq
))
383 __blk_mq_complete_request(rq
);
385 EXPORT_SYMBOL(blk_mq_complete_request
);
387 void blk_mq_start_request(struct request
*rq
)
389 struct request_queue
*q
= rq
->q
;
391 trace_block_rq_issue(q
, rq
);
393 rq
->resid_len
= blk_rq_bytes(rq
);
394 if (unlikely(blk_bidi_rq(rq
)))
395 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
400 * Ensure that ->deadline is visible before set the started
401 * flag and clear the completed flag.
403 smp_mb__before_atomic();
406 * Mark us as started and clear complete. Complete might have been
407 * set if requeue raced with timeout, which then marked it as
408 * complete. So be sure to clear complete again when we start
409 * the request, otherwise we'll ignore the completion event.
411 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
412 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
413 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
414 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
416 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
418 * Make sure space for the drain appears. We know we can do
419 * this because max_hw_segments has been adjusted to be one
420 * fewer than the device can handle.
422 rq
->nr_phys_segments
++;
425 EXPORT_SYMBOL(blk_mq_start_request
);
427 static void __blk_mq_requeue_request(struct request
*rq
)
429 struct request_queue
*q
= rq
->q
;
431 trace_block_rq_requeue(q
, rq
);
433 if (test_and_clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
434 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
435 rq
->nr_phys_segments
--;
439 void blk_mq_requeue_request(struct request
*rq
)
441 __blk_mq_requeue_request(rq
);
442 blk_clear_rq_complete(rq
);
444 BUG_ON(blk_queued_rq(rq
));
445 blk_mq_add_to_requeue_list(rq
, true);
447 EXPORT_SYMBOL(blk_mq_requeue_request
);
449 static void blk_mq_requeue_work(struct work_struct
*work
)
451 struct request_queue
*q
=
452 container_of(work
, struct request_queue
, requeue_work
);
454 struct request
*rq
, *next
;
457 spin_lock_irqsave(&q
->requeue_lock
, flags
);
458 list_splice_init(&q
->requeue_list
, &rq_list
);
459 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
461 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
462 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
465 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
466 list_del_init(&rq
->queuelist
);
467 blk_mq_insert_request(rq
, true, false, false);
470 while (!list_empty(&rq_list
)) {
471 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
472 list_del_init(&rq
->queuelist
);
473 blk_mq_insert_request(rq
, false, false, false);
477 * Use the start variant of queue running here, so that running
478 * the requeue work will kick stopped queues.
480 blk_mq_start_hw_queues(q
);
483 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
485 struct request_queue
*q
= rq
->q
;
489 * We abuse this flag that is otherwise used by the I/O scheduler to
490 * request head insertation from the workqueue.
492 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
494 spin_lock_irqsave(&q
->requeue_lock
, flags
);
496 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
497 list_add(&rq
->queuelist
, &q
->requeue_list
);
499 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
501 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
503 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
505 void blk_mq_kick_requeue_list(struct request_queue
*q
)
507 kblockd_schedule_work(&q
->requeue_work
);
509 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
511 static inline bool is_flush_request(struct request
*rq
, unsigned int tag
)
513 return ((rq
->cmd_flags
& REQ_FLUSH_SEQ
) &&
514 rq
->q
->flush_rq
->tag
== tag
);
517 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
519 struct request
*rq
= tags
->rqs
[tag
];
521 if (!is_flush_request(rq
, tag
))
524 return rq
->q
->flush_rq
;
526 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
528 struct blk_mq_timeout_data
{
529 struct blk_mq_hw_ctx
*hctx
;
531 unsigned int *next_set
;
534 static void blk_mq_timeout_check(void *__data
, unsigned long *free_tags
)
536 struct blk_mq_timeout_data
*data
= __data
;
537 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
540 /* It may not be in flight yet (this is where
541 * the REQ_ATOMIC_STARTED flag comes in). The requests are
542 * statically allocated, so we know it's always safe to access the
543 * memory associated with a bit offset into ->rqs[].
549 tag
= find_next_zero_bit(free_tags
, hctx
->tags
->nr_tags
, tag
);
550 if (tag
>= hctx
->tags
->nr_tags
)
553 rq
= blk_mq_tag_to_rq(hctx
->tags
, tag
++);
554 if (rq
->q
!= hctx
->queue
)
556 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
559 blk_rq_check_expired(rq
, data
->next
, data
->next_set
);
563 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx
*hctx
,
565 unsigned int *next_set
)
567 struct blk_mq_timeout_data data
= {
570 .next_set
= next_set
,
574 * Ask the tagging code to iterate busy requests, so we can
575 * check them for timeout.
577 blk_mq_tag_busy_iter(hctx
->tags
, blk_mq_timeout_check
, &data
);
580 static enum blk_eh_timer_return
blk_mq_rq_timed_out(struct request
*rq
)
582 struct request_queue
*q
= rq
->q
;
585 * We know that complete is set at this point. If STARTED isn't set
586 * anymore, then the request isn't active and the "timeout" should
587 * just be ignored. This can happen due to the bitflag ordering.
588 * Timeout first checks if STARTED is set, and if it is, assumes
589 * the request is active. But if we race with completion, then
590 * we both flags will get cleared. So check here again, and ignore
591 * a timeout event with a request that isn't active.
593 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
594 return BLK_EH_NOT_HANDLED
;
596 if (!q
->mq_ops
->timeout
)
597 return BLK_EH_RESET_TIMER
;
599 return q
->mq_ops
->timeout(rq
);
602 static void blk_mq_rq_timer(unsigned long data
)
604 struct request_queue
*q
= (struct request_queue
*) data
;
605 struct blk_mq_hw_ctx
*hctx
;
606 unsigned long next
= 0;
609 queue_for_each_hw_ctx(q
, hctx
, i
) {
611 * If not software queues are currently mapped to this
612 * hardware queue, there's nothing to check
614 if (!hctx
->nr_ctx
|| !hctx
->tags
)
617 blk_mq_hw_ctx_check_timeout(hctx
, &next
, &next_set
);
621 next
= blk_rq_timeout(round_jiffies_up(next
));
622 mod_timer(&q
->timeout
, next
);
624 queue_for_each_hw_ctx(q
, hctx
, i
)
625 blk_mq_tag_idle(hctx
);
630 * Reverse check our software queue for entries that we could potentially
631 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
632 * too much time checking for merges.
634 static bool blk_mq_attempt_merge(struct request_queue
*q
,
635 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
640 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
646 if (!blk_rq_merge_ok(rq
, bio
))
649 el_ret
= blk_try_merge(rq
, bio
);
650 if (el_ret
== ELEVATOR_BACK_MERGE
) {
651 if (bio_attempt_back_merge(q
, rq
, bio
)) {
656 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
657 if (bio_attempt_front_merge(q
, rq
, bio
)) {
669 * Process software queues that have been marked busy, splicing them
670 * to the for-dispatch
672 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
674 struct blk_mq_ctx
*ctx
;
677 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++) {
678 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
679 unsigned int off
, bit
;
685 off
= i
* hctx
->ctx_map
.bits_per_word
;
687 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
688 if (bit
>= bm
->depth
)
691 ctx
= hctx
->ctxs
[bit
+ off
];
692 clear_bit(bit
, &bm
->word
);
693 spin_lock(&ctx
->lock
);
694 list_splice_tail_init(&ctx
->rq_list
, list
);
695 spin_unlock(&ctx
->lock
);
703 * Run this hardware queue, pulling any software queues mapped to it in.
704 * Note that this function currently has various problems around ordering
705 * of IO. In particular, we'd like FIFO behaviour on handling existing
706 * items on the hctx->dispatch list. Ignore that for now.
708 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
710 struct request_queue
*q
= hctx
->queue
;
715 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
717 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
723 * Touch any software queue that has pending entries.
725 flush_busy_ctxs(hctx
, &rq_list
);
728 * If we have previous entries on our dispatch list, grab them
729 * and stuff them at the front for more fair dispatch.
731 if (!list_empty_careful(&hctx
->dispatch
)) {
732 spin_lock(&hctx
->lock
);
733 if (!list_empty(&hctx
->dispatch
))
734 list_splice_init(&hctx
->dispatch
, &rq_list
);
735 spin_unlock(&hctx
->lock
);
739 * Now process all the entries, sending them to the driver.
742 while (!list_empty(&rq_list
)) {
745 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
746 list_del_init(&rq
->queuelist
);
748 ret
= q
->mq_ops
->queue_rq(hctx
, rq
, list_empty(&rq_list
));
750 case BLK_MQ_RQ_QUEUE_OK
:
753 case BLK_MQ_RQ_QUEUE_BUSY
:
754 list_add(&rq
->queuelist
, &rq_list
);
755 __blk_mq_requeue_request(rq
);
758 pr_err("blk-mq: bad return on queue: %d\n", ret
);
759 case BLK_MQ_RQ_QUEUE_ERROR
:
761 blk_mq_end_request(rq
, rq
->errors
);
765 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
770 hctx
->dispatched
[0]++;
771 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
772 hctx
->dispatched
[ilog2(queued
) + 1]++;
775 * Any items that need requeuing? Stuff them into hctx->dispatch,
776 * that is where we will continue on next queue run.
778 if (!list_empty(&rq_list
)) {
779 spin_lock(&hctx
->lock
);
780 list_splice(&rq_list
, &hctx
->dispatch
);
781 spin_unlock(&hctx
->lock
);
786 * It'd be great if the workqueue API had a way to pass
787 * in a mask and had some smarts for more clever placement.
788 * For now we just round-robin here, switching for every
789 * BLK_MQ_CPU_WORK_BATCH queued items.
791 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
793 int cpu
= hctx
->next_cpu
;
795 if (--hctx
->next_cpu_batch
<= 0) {
798 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
799 if (next_cpu
>= nr_cpu_ids
)
800 next_cpu
= cpumask_first(hctx
->cpumask
);
802 hctx
->next_cpu
= next_cpu
;
803 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
809 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
811 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
814 if (!async
&& cpumask_test_cpu(smp_processor_id(), hctx
->cpumask
))
815 __blk_mq_run_hw_queue(hctx
);
816 else if (hctx
->queue
->nr_hw_queues
== 1)
817 kblockd_schedule_delayed_work(&hctx
->run_work
, 0);
821 cpu
= blk_mq_hctx_next_cpu(hctx
);
822 kblockd_schedule_delayed_work_on(cpu
, &hctx
->run_work
, 0);
826 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
828 struct blk_mq_hw_ctx
*hctx
;
831 queue_for_each_hw_ctx(q
, hctx
, i
) {
832 if ((!blk_mq_hctx_has_pending(hctx
) &&
833 list_empty_careful(&hctx
->dispatch
)) ||
834 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
838 blk_mq_run_hw_queue(hctx
, async
);
842 EXPORT_SYMBOL(blk_mq_run_queues
);
844 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
846 cancel_delayed_work(&hctx
->run_work
);
847 cancel_delayed_work(&hctx
->delay_work
);
848 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
850 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
852 void blk_mq_stop_hw_queues(struct request_queue
*q
)
854 struct blk_mq_hw_ctx
*hctx
;
857 queue_for_each_hw_ctx(q
, hctx
, i
)
858 blk_mq_stop_hw_queue(hctx
);
860 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
862 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
864 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
867 blk_mq_run_hw_queue(hctx
, false);
870 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
872 void blk_mq_start_hw_queues(struct request_queue
*q
)
874 struct blk_mq_hw_ctx
*hctx
;
877 queue_for_each_hw_ctx(q
, hctx
, i
)
878 blk_mq_start_hw_queue(hctx
);
880 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
883 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
885 struct blk_mq_hw_ctx
*hctx
;
888 queue_for_each_hw_ctx(q
, hctx
, i
) {
889 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
892 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
894 blk_mq_run_hw_queue(hctx
, async
);
898 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
900 static void blk_mq_run_work_fn(struct work_struct
*work
)
902 struct blk_mq_hw_ctx
*hctx
;
904 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
906 __blk_mq_run_hw_queue(hctx
);
909 static void blk_mq_delay_work_fn(struct work_struct
*work
)
911 struct blk_mq_hw_ctx
*hctx
;
913 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
915 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
916 __blk_mq_run_hw_queue(hctx
);
919 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
921 unsigned long tmo
= msecs_to_jiffies(msecs
);
923 if (hctx
->queue
->nr_hw_queues
== 1)
924 kblockd_schedule_delayed_work(&hctx
->delay_work
, tmo
);
928 cpu
= blk_mq_hctx_next_cpu(hctx
);
929 kblockd_schedule_delayed_work_on(cpu
, &hctx
->delay_work
, tmo
);
932 EXPORT_SYMBOL(blk_mq_delay_queue
);
934 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
935 struct request
*rq
, bool at_head
)
937 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
939 trace_block_rq_insert(hctx
->queue
, rq
);
942 list_add(&rq
->queuelist
, &ctx
->rq_list
);
944 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
946 blk_mq_hctx_mark_pending(hctx
, ctx
);
949 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
952 struct request_queue
*q
= rq
->q
;
953 struct blk_mq_hw_ctx
*hctx
;
954 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
956 current_ctx
= blk_mq_get_ctx(q
);
957 if (!cpu_online(ctx
->cpu
))
958 rq
->mq_ctx
= ctx
= current_ctx
;
960 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
962 spin_lock(&ctx
->lock
);
963 __blk_mq_insert_request(hctx
, rq
, at_head
);
964 spin_unlock(&ctx
->lock
);
967 blk_mq_run_hw_queue(hctx
, async
);
969 blk_mq_put_ctx(current_ctx
);
972 static void blk_mq_insert_requests(struct request_queue
*q
,
973 struct blk_mq_ctx
*ctx
,
974 struct list_head
*list
,
979 struct blk_mq_hw_ctx
*hctx
;
980 struct blk_mq_ctx
*current_ctx
;
982 trace_block_unplug(q
, depth
, !from_schedule
);
984 current_ctx
= blk_mq_get_ctx(q
);
986 if (!cpu_online(ctx
->cpu
))
988 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
991 * preemption doesn't flush plug list, so it's possible ctx->cpu is
994 spin_lock(&ctx
->lock
);
995 while (!list_empty(list
)) {
998 rq
= list_first_entry(list
, struct request
, queuelist
);
999 list_del_init(&rq
->queuelist
);
1001 __blk_mq_insert_request(hctx
, rq
, false);
1003 spin_unlock(&ctx
->lock
);
1005 blk_mq_run_hw_queue(hctx
, from_schedule
);
1006 blk_mq_put_ctx(current_ctx
);
1009 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1011 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1012 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1014 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1015 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1016 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1019 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1021 struct blk_mq_ctx
*this_ctx
;
1022 struct request_queue
*this_q
;
1025 LIST_HEAD(ctx_list
);
1028 list_splice_init(&plug
->mq_list
, &list
);
1030 list_sort(NULL
, &list
, plug_ctx_cmp
);
1036 while (!list_empty(&list
)) {
1037 rq
= list_entry_rq(list
.next
);
1038 list_del_init(&rq
->queuelist
);
1040 if (rq
->mq_ctx
!= this_ctx
) {
1042 blk_mq_insert_requests(this_q
, this_ctx
,
1047 this_ctx
= rq
->mq_ctx
;
1053 list_add_tail(&rq
->queuelist
, &ctx_list
);
1057 * If 'this_ctx' is set, we know we have entries to complete
1058 * on 'ctx_list'. Do those.
1061 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1066 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1068 init_request_from_bio(rq
, bio
);
1070 if (blk_do_io_stat(rq
))
1071 blk_account_io_start(rq
, 1);
1074 static inline bool hctx_allow_merges(struct blk_mq_hw_ctx
*hctx
)
1076 return (hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
1077 !blk_queue_nomerges(hctx
->queue
);
1080 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1081 struct blk_mq_ctx
*ctx
,
1082 struct request
*rq
, struct bio
*bio
)
1084 if (!hctx_allow_merges(hctx
)) {
1085 blk_mq_bio_to_request(rq
, bio
);
1086 spin_lock(&ctx
->lock
);
1088 __blk_mq_insert_request(hctx
, rq
, false);
1089 spin_unlock(&ctx
->lock
);
1092 struct request_queue
*q
= hctx
->queue
;
1094 spin_lock(&ctx
->lock
);
1095 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1096 blk_mq_bio_to_request(rq
, bio
);
1100 spin_unlock(&ctx
->lock
);
1101 __blk_mq_free_request(hctx
, ctx
, rq
);
1106 struct blk_map_ctx
{
1107 struct blk_mq_hw_ctx
*hctx
;
1108 struct blk_mq_ctx
*ctx
;
1111 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1113 struct blk_map_ctx
*data
)
1115 struct blk_mq_hw_ctx
*hctx
;
1116 struct blk_mq_ctx
*ctx
;
1118 int rw
= bio_data_dir(bio
);
1119 struct blk_mq_alloc_data alloc_data
;
1121 if (unlikely(blk_mq_queue_enter(q
))) {
1122 bio_endio(bio
, -EIO
);
1126 ctx
= blk_mq_get_ctx(q
);
1127 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1129 if (rw_is_sync(bio
->bi_rw
))
1132 trace_block_getrq(q
, bio
, rw
);
1133 blk_mq_set_alloc_data(&alloc_data
, q
, GFP_ATOMIC
, false, ctx
,
1135 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1136 if (unlikely(!rq
)) {
1137 __blk_mq_run_hw_queue(hctx
);
1138 blk_mq_put_ctx(ctx
);
1139 trace_block_sleeprq(q
, bio
, rw
);
1141 ctx
= blk_mq_get_ctx(q
);
1142 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1143 blk_mq_set_alloc_data(&alloc_data
, q
,
1144 __GFP_WAIT
|GFP_ATOMIC
, false, ctx
, hctx
);
1145 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1146 ctx
= alloc_data
.ctx
;
1147 hctx
= alloc_data
.hctx
;
1157 * Multiple hardware queue variant. This will not use per-process plugs,
1158 * but will attempt to bypass the hctx queueing if we can go straight to
1159 * hardware for SYNC IO.
1161 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1163 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1164 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1165 struct blk_map_ctx data
;
1168 blk_queue_bounce(q
, &bio
);
1170 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1171 bio_endio(bio
, -EIO
);
1175 rq
= blk_mq_map_request(q
, bio
, &data
);
1179 if (unlikely(is_flush_fua
)) {
1180 blk_mq_bio_to_request(rq
, bio
);
1181 blk_insert_flush(rq
);
1188 blk_mq_bio_to_request(rq
, bio
);
1191 * For OK queue, we are done. For error, kill it. Any other
1192 * error (busy), just add it to our list as we previously
1195 ret
= q
->mq_ops
->queue_rq(data
.hctx
, rq
, true);
1196 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1199 __blk_mq_requeue_request(rq
);
1201 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1203 blk_mq_end_request(rq
, rq
->errors
);
1209 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1211 * For a SYNC request, send it to the hardware immediately. For
1212 * an ASYNC request, just ensure that we run it later on. The
1213 * latter allows for merging opportunities and more efficient
1217 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1220 blk_mq_put_ctx(data
.ctx
);
1224 * Single hardware queue variant. This will attempt to use any per-process
1225 * plug for merging and IO deferral.
1227 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1229 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1230 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1231 unsigned int use_plug
, request_count
= 0;
1232 struct blk_map_ctx data
;
1236 * If we have multiple hardware queues, just go directly to
1237 * one of those for sync IO.
1239 use_plug
= !is_flush_fua
&& !is_sync
;
1241 blk_queue_bounce(q
, &bio
);
1243 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1244 bio_endio(bio
, -EIO
);
1248 if (use_plug
&& !blk_queue_nomerges(q
) &&
1249 blk_attempt_plug_merge(q
, bio
, &request_count
))
1252 rq
= blk_mq_map_request(q
, bio
, &data
);
1256 if (unlikely(is_flush_fua
)) {
1257 blk_mq_bio_to_request(rq
, bio
);
1258 blk_insert_flush(rq
);
1263 * A task plug currently exists. Since this is completely lockless,
1264 * utilize that to temporarily store requests until the task is
1265 * either done or scheduled away.
1268 struct blk_plug
*plug
= current
->plug
;
1271 blk_mq_bio_to_request(rq
, bio
);
1272 if (list_empty(&plug
->mq_list
))
1273 trace_block_plug(q
);
1274 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1275 blk_flush_plug_list(plug
, false);
1276 trace_block_plug(q
);
1278 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1279 blk_mq_put_ctx(data
.ctx
);
1284 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1286 * For a SYNC request, send it to the hardware immediately. For
1287 * an ASYNC request, just ensure that we run it later on. The
1288 * latter allows for merging opportunities and more efficient
1292 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1295 blk_mq_put_ctx(data
.ctx
);
1299 * Default mapping to a software queue, since we use one per CPU.
1301 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1303 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1305 EXPORT_SYMBOL(blk_mq_map_queue
);
1307 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1308 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1312 if (tags
->rqs
&& set
->ops
->exit_request
) {
1315 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1318 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1320 tags
->rqs
[i
] = NULL
;
1324 while (!list_empty(&tags
->page_list
)) {
1325 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1326 list_del_init(&page
->lru
);
1327 __free_pages(page
, page
->private);
1332 blk_mq_free_tags(tags
);
1335 static size_t order_to_size(unsigned int order
)
1337 return (size_t)PAGE_SIZE
<< order
;
1340 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1341 unsigned int hctx_idx
)
1343 struct blk_mq_tags
*tags
;
1344 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1345 size_t rq_size
, left
;
1347 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1352 INIT_LIST_HEAD(&tags
->page_list
);
1354 tags
->rqs
= kzalloc_node(set
->queue_depth
* sizeof(struct request
*),
1355 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1358 blk_mq_free_tags(tags
);
1363 * rq_size is the size of the request plus driver payload, rounded
1364 * to the cacheline size
1366 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1368 left
= rq_size
* set
->queue_depth
;
1370 for (i
= 0; i
< set
->queue_depth
; ) {
1371 int this_order
= max_order
;
1376 while (left
< order_to_size(this_order
- 1) && this_order
)
1380 page
= alloc_pages_node(set
->numa_node
,
1381 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1387 if (order_to_size(this_order
) < rq_size
)
1394 page
->private = this_order
;
1395 list_add_tail(&page
->lru
, &tags
->page_list
);
1397 p
= page_address(page
);
1398 entries_per_page
= order_to_size(this_order
) / rq_size
;
1399 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1400 left
-= to_do
* rq_size
;
1401 for (j
= 0; j
< to_do
; j
++) {
1403 tags
->rqs
[i
]->atomic_flags
= 0;
1404 tags
->rqs
[i
]->cmd_flags
= 0;
1405 if (set
->ops
->init_request
) {
1406 if (set
->ops
->init_request(set
->driver_data
,
1407 tags
->rqs
[i
], hctx_idx
, i
,
1409 tags
->rqs
[i
] = NULL
;
1422 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1426 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1431 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1433 unsigned int bpw
= 8, total
, num_maps
, i
;
1435 bitmap
->bits_per_word
= bpw
;
1437 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1438 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1443 bitmap
->map_size
= num_maps
;
1446 for (i
= 0; i
< num_maps
; i
++) {
1447 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1448 total
-= bitmap
->map
[i
].depth
;
1454 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1456 struct request_queue
*q
= hctx
->queue
;
1457 struct blk_mq_ctx
*ctx
;
1461 * Move ctx entries to new CPU, if this one is going away.
1463 ctx
= __blk_mq_get_ctx(q
, cpu
);
1465 spin_lock(&ctx
->lock
);
1466 if (!list_empty(&ctx
->rq_list
)) {
1467 list_splice_init(&ctx
->rq_list
, &tmp
);
1468 blk_mq_hctx_clear_pending(hctx
, ctx
);
1470 spin_unlock(&ctx
->lock
);
1472 if (list_empty(&tmp
))
1475 ctx
= blk_mq_get_ctx(q
);
1476 spin_lock(&ctx
->lock
);
1478 while (!list_empty(&tmp
)) {
1481 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1483 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1486 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1487 blk_mq_hctx_mark_pending(hctx
, ctx
);
1489 spin_unlock(&ctx
->lock
);
1491 blk_mq_run_hw_queue(hctx
, true);
1492 blk_mq_put_ctx(ctx
);
1496 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1498 struct request_queue
*q
= hctx
->queue
;
1499 struct blk_mq_tag_set
*set
= q
->tag_set
;
1501 if (set
->tags
[hctx
->queue_num
])
1504 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1505 if (!set
->tags
[hctx
->queue_num
])
1508 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1512 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1515 struct blk_mq_hw_ctx
*hctx
= data
;
1517 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1518 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1519 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1520 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1525 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1526 struct blk_mq_tag_set
*set
, int nr_queue
)
1528 struct blk_mq_hw_ctx
*hctx
;
1531 queue_for_each_hw_ctx(q
, hctx
, i
) {
1535 blk_mq_tag_idle(hctx
);
1537 if (set
->ops
->exit_hctx
)
1538 set
->ops
->exit_hctx(hctx
, i
);
1540 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1542 blk_mq_free_bitmap(&hctx
->ctx_map
);
1547 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1548 struct blk_mq_tag_set
*set
)
1550 struct blk_mq_hw_ctx
*hctx
;
1553 queue_for_each_hw_ctx(q
, hctx
, i
) {
1554 free_cpumask_var(hctx
->cpumask
);
1559 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1560 struct blk_mq_tag_set
*set
)
1562 struct blk_mq_hw_ctx
*hctx
;
1566 * Initialize hardware queues
1568 queue_for_each_hw_ctx(q
, hctx
, i
) {
1571 node
= hctx
->numa_node
;
1572 if (node
== NUMA_NO_NODE
)
1573 node
= hctx
->numa_node
= set
->numa_node
;
1575 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1576 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1577 spin_lock_init(&hctx
->lock
);
1578 INIT_LIST_HEAD(&hctx
->dispatch
);
1580 hctx
->queue_num
= i
;
1581 hctx
->flags
= set
->flags
;
1582 hctx
->cmd_size
= set
->cmd_size
;
1584 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1585 blk_mq_hctx_notify
, hctx
);
1586 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1588 hctx
->tags
= set
->tags
[i
];
1591 * Allocate space for all possible cpus to avoid allocation at
1594 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1599 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1604 if (set
->ops
->init_hctx
&&
1605 set
->ops
->init_hctx(hctx
, set
->driver_data
, i
))
1609 if (i
== q
->nr_hw_queues
)
1615 blk_mq_exit_hw_queues(q
, set
, i
);
1620 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1621 unsigned int nr_hw_queues
)
1625 for_each_possible_cpu(i
) {
1626 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1627 struct blk_mq_hw_ctx
*hctx
;
1629 memset(__ctx
, 0, sizeof(*__ctx
));
1631 spin_lock_init(&__ctx
->lock
);
1632 INIT_LIST_HEAD(&__ctx
->rq_list
);
1635 /* If the cpu isn't online, the cpu is mapped to first hctx */
1639 hctx
= q
->mq_ops
->map_queue(q
, i
);
1640 cpumask_set_cpu(i
, hctx
->cpumask
);
1644 * Set local node, IFF we have more than one hw queue. If
1645 * not, we remain on the home node of the device
1647 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1648 hctx
->numa_node
= cpu_to_node(i
);
1652 static void blk_mq_map_swqueue(struct request_queue
*q
)
1655 struct blk_mq_hw_ctx
*hctx
;
1656 struct blk_mq_ctx
*ctx
;
1658 queue_for_each_hw_ctx(q
, hctx
, i
) {
1659 cpumask_clear(hctx
->cpumask
);
1664 * Map software to hardware queues
1666 queue_for_each_ctx(q
, ctx
, i
) {
1667 /* If the cpu isn't online, the cpu is mapped to first hctx */
1671 hctx
= q
->mq_ops
->map_queue(q
, i
);
1672 cpumask_set_cpu(i
, hctx
->cpumask
);
1673 ctx
->index_hw
= hctx
->nr_ctx
;
1674 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1677 queue_for_each_hw_ctx(q
, hctx
, i
) {
1679 * If no software queues are mapped to this hardware queue,
1680 * disable it and free the request entries.
1682 if (!hctx
->nr_ctx
) {
1683 struct blk_mq_tag_set
*set
= q
->tag_set
;
1686 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1687 set
->tags
[i
] = NULL
;
1694 * Initialize batch roundrobin counts
1696 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1697 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1701 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1703 struct blk_mq_hw_ctx
*hctx
;
1704 struct request_queue
*q
;
1708 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1713 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1714 blk_mq_freeze_queue(q
);
1716 queue_for_each_hw_ctx(q
, hctx
, i
) {
1718 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1720 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1722 blk_mq_unfreeze_queue(q
);
1726 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1728 struct blk_mq_tag_set
*set
= q
->tag_set
;
1730 mutex_lock(&set
->tag_list_lock
);
1731 list_del_init(&q
->tag_set_list
);
1732 blk_mq_update_tag_set_depth(set
);
1733 mutex_unlock(&set
->tag_list_lock
);
1736 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1737 struct request_queue
*q
)
1741 mutex_lock(&set
->tag_list_lock
);
1742 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1743 blk_mq_update_tag_set_depth(set
);
1744 mutex_unlock(&set
->tag_list_lock
);
1747 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1749 struct blk_mq_hw_ctx
**hctxs
;
1750 struct blk_mq_ctx __percpu
*ctx
;
1751 struct request_queue
*q
;
1755 ctx
= alloc_percpu(struct blk_mq_ctx
);
1757 return ERR_PTR(-ENOMEM
);
1759 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1765 map
= blk_mq_make_queue_map(set
);
1769 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1770 int node
= blk_mq_hw_queue_to_node(map
, i
);
1772 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
1777 if (!zalloc_cpumask_var(&hctxs
[i
]->cpumask
, GFP_KERNEL
))
1780 atomic_set(&hctxs
[i
]->nr_active
, 0);
1781 hctxs
[i
]->numa_node
= node
;
1782 hctxs
[i
]->queue_num
= i
;
1785 q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1789 if (percpu_ref_init(&q
->mq_usage_counter
, blk_mq_usage_counter_release
))
1792 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1793 blk_queue_rq_timeout(q
, 30000);
1795 q
->nr_queues
= nr_cpu_ids
;
1796 q
->nr_hw_queues
= set
->nr_hw_queues
;
1800 q
->queue_hw_ctx
= hctxs
;
1802 q
->mq_ops
= set
->ops
;
1803 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1805 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
1806 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
1808 q
->sg_reserved_size
= INT_MAX
;
1810 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
1811 INIT_LIST_HEAD(&q
->requeue_list
);
1812 spin_lock_init(&q
->requeue_lock
);
1814 if (q
->nr_hw_queues
> 1)
1815 blk_queue_make_request(q
, blk_mq_make_request
);
1817 blk_queue_make_request(q
, blk_sq_make_request
);
1819 blk_queue_rq_timed_out(q
, blk_mq_rq_timed_out
);
1821 blk_queue_rq_timeout(q
, set
->timeout
);
1824 * Do this after blk_queue_make_request() overrides it...
1826 q
->nr_requests
= set
->queue_depth
;
1828 if (set
->ops
->complete
)
1829 blk_queue_softirq_done(q
, set
->ops
->complete
);
1831 blk_mq_init_flush(q
);
1832 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
1834 q
->flush_rq
= kzalloc(round_up(sizeof(struct request
) +
1835 set
->cmd_size
, cache_line_size()),
1840 if (blk_mq_init_hw_queues(q
, set
))
1843 mutex_lock(&all_q_mutex
);
1844 list_add_tail(&q
->all_q_node
, &all_q_list
);
1845 mutex_unlock(&all_q_mutex
);
1847 blk_mq_add_queue_tag_set(set
, q
);
1849 blk_mq_map_swqueue(q
);
1856 blk_cleanup_queue(q
);
1859 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1862 free_cpumask_var(hctxs
[i
]->cpumask
);
1869 return ERR_PTR(-ENOMEM
);
1871 EXPORT_SYMBOL(blk_mq_init_queue
);
1873 void blk_mq_free_queue(struct request_queue
*q
)
1875 struct blk_mq_tag_set
*set
= q
->tag_set
;
1877 blk_mq_del_queue_tag_set(q
);
1879 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1880 blk_mq_free_hw_queues(q
, set
);
1882 percpu_ref_exit(&q
->mq_usage_counter
);
1884 free_percpu(q
->queue_ctx
);
1885 kfree(q
->queue_hw_ctx
);
1888 q
->queue_ctx
= NULL
;
1889 q
->queue_hw_ctx
= NULL
;
1892 mutex_lock(&all_q_mutex
);
1893 list_del_init(&q
->all_q_node
);
1894 mutex_unlock(&all_q_mutex
);
1897 /* Basically redo blk_mq_init_queue with queue frozen */
1898 static void blk_mq_queue_reinit(struct request_queue
*q
)
1900 blk_mq_freeze_queue(q
);
1902 blk_mq_sysfs_unregister(q
);
1904 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1907 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1908 * we should change hctx numa_node according to new topology (this
1909 * involves free and re-allocate memory, worthy doing?)
1912 blk_mq_map_swqueue(q
);
1914 blk_mq_sysfs_register(q
);
1916 blk_mq_unfreeze_queue(q
);
1919 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1920 unsigned long action
, void *hcpu
)
1922 struct request_queue
*q
;
1925 * Before new mappings are established, hotadded cpu might already
1926 * start handling requests. This doesn't break anything as we map
1927 * offline CPUs to first hardware queue. We will re-init the queue
1928 * below to get optimal settings.
1930 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1931 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1934 mutex_lock(&all_q_mutex
);
1935 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1936 blk_mq_queue_reinit(q
);
1937 mutex_unlock(&all_q_mutex
);
1941 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
1945 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1946 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
1955 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1961 * Allocate the request maps associated with this tag_set. Note that this
1962 * may reduce the depth asked for, if memory is tight. set->queue_depth
1963 * will be updated to reflect the allocated depth.
1965 static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
1970 depth
= set
->queue_depth
;
1972 err
= __blk_mq_alloc_rq_maps(set
);
1976 set
->queue_depth
>>= 1;
1977 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
1981 } while (set
->queue_depth
);
1983 if (!set
->queue_depth
|| err
) {
1984 pr_err("blk-mq: failed to allocate request map\n");
1988 if (depth
!= set
->queue_depth
)
1989 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
1990 depth
, set
->queue_depth
);
1996 * Alloc a tag set to be associated with one or more request queues.
1997 * May fail with EINVAL for various error conditions. May adjust the
1998 * requested depth down, if if it too large. In that case, the set
1999 * value will be stored in set->queue_depth.
2001 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
2003 if (!set
->nr_hw_queues
)
2005 if (!set
->queue_depth
)
2007 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
2010 if (!set
->nr_hw_queues
|| !set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
2013 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
2014 pr_info("blk-mq: reduced tag depth to %u\n",
2016 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
2019 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
2020 sizeof(struct blk_mq_tags
*),
2021 GFP_KERNEL
, set
->numa_node
);
2025 if (blk_mq_alloc_rq_maps(set
))
2028 mutex_init(&set
->tag_list_lock
);
2029 INIT_LIST_HEAD(&set
->tag_list
);
2037 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2039 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2043 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2045 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2051 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2053 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2055 struct blk_mq_tag_set
*set
= q
->tag_set
;
2056 struct blk_mq_hw_ctx
*hctx
;
2059 if (!set
|| nr
> set
->queue_depth
)
2063 queue_for_each_hw_ctx(q
, hctx
, i
) {
2064 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2070 q
->nr_requests
= nr
;
2075 void blk_mq_disable_hotplug(void)
2077 mutex_lock(&all_q_mutex
);
2080 void blk_mq_enable_hotplug(void)
2082 mutex_unlock(&all_q_mutex
);
2085 static int __init
blk_mq_init(void)
2089 hotcpu_notifier(blk_mq_queue_reinit_notify
, 0);
2093 subsys_initcall(blk_mq_init
);