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);
85 /* we have problems to freeze the queue if it's initializing */
86 if (!blk_queue_bypass(q
) || !blk_queue_init_done(q
))
89 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
91 spin_lock_irq(q
->queue_lock
);
92 ret
= wait_event_interruptible_lock_irq(q
->mq_freeze_wq
,
93 !blk_queue_bypass(q
) || blk_queue_dying(q
),
95 /* inc usage with lock hold to avoid freeze_queue runs here */
96 if (!ret
&& !blk_queue_dying(q
))
97 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
98 else if (blk_queue_dying(q
))
100 spin_unlock_irq(q
->queue_lock
);
105 static void blk_mq_queue_exit(struct request_queue
*q
)
107 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
110 static void __blk_mq_drain_queue(struct request_queue
*q
)
115 spin_lock_irq(q
->queue_lock
);
116 count
= percpu_counter_sum(&q
->mq_usage_counter
);
117 spin_unlock_irq(q
->queue_lock
);
121 blk_mq_run_queues(q
, false);
127 * Guarantee no request is in use, so we can change any data structure of
128 * the queue afterward.
130 static void blk_mq_freeze_queue(struct request_queue
*q
)
134 spin_lock_irq(q
->queue_lock
);
135 drain
= !q
->bypass_depth
++;
136 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
137 spin_unlock_irq(q
->queue_lock
);
140 __blk_mq_drain_queue(q
);
143 void blk_mq_drain_queue(struct request_queue
*q
)
145 __blk_mq_drain_queue(q
);
148 static void blk_mq_unfreeze_queue(struct request_queue
*q
)
152 spin_lock_irq(q
->queue_lock
);
153 if (!--q
->bypass_depth
) {
154 queue_flag_clear(QUEUE_FLAG_BYPASS
, q
);
157 WARN_ON_ONCE(q
->bypass_depth
< 0);
158 spin_unlock_irq(q
->queue_lock
);
160 wake_up_all(&q
->mq_freeze_wq
);
163 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
165 return blk_mq_has_free_tags(hctx
->tags
);
167 EXPORT_SYMBOL(blk_mq_can_queue
);
169 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
170 struct request
*rq
, unsigned int rw_flags
)
172 if (blk_queue_io_stat(q
))
173 rw_flags
|= REQ_IO_STAT
;
175 INIT_LIST_HEAD(&rq
->queuelist
);
176 /* csd/requeue_work/fifo_time is initialized before use */
179 rq
->cmd_flags
|= rw_flags
;
180 /* do not touch atomic flags, it needs atomic ops against the timer */
182 INIT_HLIST_NODE(&rq
->hash
);
183 RB_CLEAR_NODE(&rq
->rb_node
);
186 #ifdef CONFIG_BLK_CGROUP
188 set_start_time_ns(rq
);
189 rq
->io_start_time_ns
= 0;
191 rq
->nr_phys_segments
= 0;
192 #if defined(CONFIG_BLK_DEV_INTEGRITY)
193 rq
->nr_integrity_segments
= 0;
196 /* tag was already set */
204 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
);
410 * Just mark start time and set the started bit. Due to memory
411 * ordering, we know we'll see the correct deadline as long as
412 * REQ_ATOMIC_STARTED is seen. Use the default queue timeout,
413 * unless one has been set in the request.
416 rq
->deadline
= jiffies
+ q
->rq_timeout
;
418 rq
->deadline
= jiffies
+ rq
->timeout
;
421 * Mark us as started and clear complete. Complete might have been
422 * set if requeue raced with timeout, which then marked it as
423 * complete. So be sure to clear complete again when we start
424 * the request, otherwise we'll ignore the completion event.
426 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
427 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
428 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
429 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
431 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
433 * Make sure space for the drain appears. We know we can do
434 * this because max_hw_segments has been adjusted to be one
435 * fewer than the device can handle.
437 rq
->nr_phys_segments
++;
441 * Flag the last request in the series so that drivers know when IO
442 * should be kicked off, if they don't do it on a per-request basis.
444 * Note: the flag isn't the only condition drivers should do kick off.
445 * If drive is busy, the last request might not have the bit set.
448 rq
->cmd_flags
|= REQ_END
;
451 static void __blk_mq_requeue_request(struct request
*rq
)
453 struct request_queue
*q
= rq
->q
;
455 trace_block_rq_requeue(q
, rq
);
456 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
458 rq
->cmd_flags
&= ~REQ_END
;
460 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
461 rq
->nr_phys_segments
--;
464 void blk_mq_requeue_request(struct request
*rq
)
466 __blk_mq_requeue_request(rq
);
467 blk_clear_rq_complete(rq
);
469 BUG_ON(blk_queued_rq(rq
));
470 blk_mq_add_to_requeue_list(rq
, true);
472 EXPORT_SYMBOL(blk_mq_requeue_request
);
474 static void blk_mq_requeue_work(struct work_struct
*work
)
476 struct request_queue
*q
=
477 container_of(work
, struct request_queue
, requeue_work
);
479 struct request
*rq
, *next
;
482 spin_lock_irqsave(&q
->requeue_lock
, flags
);
483 list_splice_init(&q
->requeue_list
, &rq_list
);
484 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
486 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
487 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
490 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
491 list_del_init(&rq
->queuelist
);
492 blk_mq_insert_request(rq
, true, false, false);
495 while (!list_empty(&rq_list
)) {
496 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
497 list_del_init(&rq
->queuelist
);
498 blk_mq_insert_request(rq
, false, false, false);
501 blk_mq_run_queues(q
, false);
504 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
506 struct request_queue
*q
= rq
->q
;
510 * We abuse this flag that is otherwise used by the I/O scheduler to
511 * request head insertation from the workqueue.
513 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
515 spin_lock_irqsave(&q
->requeue_lock
, flags
);
517 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
518 list_add(&rq
->queuelist
, &q
->requeue_list
);
520 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
522 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
524 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
526 void blk_mq_kick_requeue_list(struct request_queue
*q
)
528 kblockd_schedule_work(&q
->requeue_work
);
530 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
532 struct request
*blk_mq_tag_to_rq(struct blk_mq_hw_ctx
*hctx
, unsigned int tag
)
534 struct request_queue
*q
= hctx
->queue
;
536 if ((q
->flush_rq
->cmd_flags
& REQ_FLUSH_SEQ
) &&
537 q
->flush_rq
->tag
== tag
)
540 return hctx
->tags
->rqs
[tag
];
542 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
544 struct blk_mq_timeout_data
{
545 struct blk_mq_hw_ctx
*hctx
;
547 unsigned int *next_set
;
550 static void blk_mq_timeout_check(void *__data
, unsigned long *free_tags
)
552 struct blk_mq_timeout_data
*data
= __data
;
553 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
556 /* It may not be in flight yet (this is where
557 * the REQ_ATOMIC_STARTED flag comes in). The requests are
558 * statically allocated, so we know it's always safe to access the
559 * memory associated with a bit offset into ->rqs[].
565 tag
= find_next_zero_bit(free_tags
, hctx
->tags
->nr_tags
, tag
);
566 if (tag
>= hctx
->tags
->nr_tags
)
569 rq
= blk_mq_tag_to_rq(hctx
, tag
++);
570 if (rq
->q
!= hctx
->queue
)
572 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
575 blk_rq_check_expired(rq
, data
->next
, data
->next_set
);
579 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx
*hctx
,
581 unsigned int *next_set
)
583 struct blk_mq_timeout_data data
= {
586 .next_set
= next_set
,
590 * Ask the tagging code to iterate busy requests, so we can
591 * check them for timeout.
593 blk_mq_tag_busy_iter(hctx
->tags
, blk_mq_timeout_check
, &data
);
596 static enum blk_eh_timer_return
blk_mq_rq_timed_out(struct request
*rq
)
598 struct request_queue
*q
= rq
->q
;
601 * We know that complete is set at this point. If STARTED isn't set
602 * anymore, then the request isn't active and the "timeout" should
603 * just be ignored. This can happen due to the bitflag ordering.
604 * Timeout first checks if STARTED is set, and if it is, assumes
605 * the request is active. But if we race with completion, then
606 * we both flags will get cleared. So check here again, and ignore
607 * a timeout event with a request that isn't active.
609 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
610 return BLK_EH_NOT_HANDLED
;
612 if (!q
->mq_ops
->timeout
)
613 return BLK_EH_RESET_TIMER
;
615 return q
->mq_ops
->timeout(rq
);
618 static void blk_mq_rq_timer(unsigned long data
)
620 struct request_queue
*q
= (struct request_queue
*) data
;
621 struct blk_mq_hw_ctx
*hctx
;
622 unsigned long next
= 0;
625 queue_for_each_hw_ctx(q
, hctx
, i
) {
627 * If not software queues are currently mapped to this
628 * hardware queue, there's nothing to check
630 if (!hctx
->nr_ctx
|| !hctx
->tags
)
633 blk_mq_hw_ctx_check_timeout(hctx
, &next
, &next_set
);
637 next
= blk_rq_timeout(round_jiffies_up(next
));
638 mod_timer(&q
->timeout
, next
);
640 queue_for_each_hw_ctx(q
, hctx
, i
)
641 blk_mq_tag_idle(hctx
);
646 * Reverse check our software queue for entries that we could potentially
647 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
648 * too much time checking for merges.
650 static bool blk_mq_attempt_merge(struct request_queue
*q
,
651 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
656 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
662 if (!blk_rq_merge_ok(rq
, bio
))
665 el_ret
= blk_try_merge(rq
, bio
);
666 if (el_ret
== ELEVATOR_BACK_MERGE
) {
667 if (bio_attempt_back_merge(q
, rq
, bio
)) {
672 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
673 if (bio_attempt_front_merge(q
, rq
, bio
)) {
685 * Process software queues that have been marked busy, splicing them
686 * to the for-dispatch
688 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
690 struct blk_mq_ctx
*ctx
;
693 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++) {
694 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
695 unsigned int off
, bit
;
701 off
= i
* hctx
->ctx_map
.bits_per_word
;
703 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
704 if (bit
>= bm
->depth
)
707 ctx
= hctx
->ctxs
[bit
+ off
];
708 clear_bit(bit
, &bm
->word
);
709 spin_lock(&ctx
->lock
);
710 list_splice_tail_init(&ctx
->rq_list
, list
);
711 spin_unlock(&ctx
->lock
);
719 * Run this hardware queue, pulling any software queues mapped to it in.
720 * Note that this function currently has various problems around ordering
721 * of IO. In particular, we'd like FIFO behaviour on handling existing
722 * items on the hctx->dispatch list. Ignore that for now.
724 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
726 struct request_queue
*q
= hctx
->queue
;
731 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
733 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
739 * Touch any software queue that has pending entries.
741 flush_busy_ctxs(hctx
, &rq_list
);
744 * If we have previous entries on our dispatch list, grab them
745 * and stuff them at the front for more fair dispatch.
747 if (!list_empty_careful(&hctx
->dispatch
)) {
748 spin_lock(&hctx
->lock
);
749 if (!list_empty(&hctx
->dispatch
))
750 list_splice_init(&hctx
->dispatch
, &rq_list
);
751 spin_unlock(&hctx
->lock
);
755 * Now process all the entries, sending them to the driver.
758 while (!list_empty(&rq_list
)) {
761 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
762 list_del_init(&rq
->queuelist
);
764 blk_mq_start_request(rq
, list_empty(&rq_list
));
766 ret
= q
->mq_ops
->queue_rq(hctx
, rq
);
768 case BLK_MQ_RQ_QUEUE_OK
:
771 case BLK_MQ_RQ_QUEUE_BUSY
:
772 list_add(&rq
->queuelist
, &rq_list
);
773 __blk_mq_requeue_request(rq
);
776 pr_err("blk-mq: bad return on queue: %d\n", ret
);
777 case BLK_MQ_RQ_QUEUE_ERROR
:
779 blk_mq_end_io(rq
, rq
->errors
);
783 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
788 hctx
->dispatched
[0]++;
789 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
790 hctx
->dispatched
[ilog2(queued
) + 1]++;
793 * Any items that need requeuing? Stuff them into hctx->dispatch,
794 * that is where we will continue on next queue run.
796 if (!list_empty(&rq_list
)) {
797 spin_lock(&hctx
->lock
);
798 list_splice(&rq_list
, &hctx
->dispatch
);
799 spin_unlock(&hctx
->lock
);
804 * It'd be great if the workqueue API had a way to pass
805 * in a mask and had some smarts for more clever placement.
806 * For now we just round-robin here, switching for every
807 * BLK_MQ_CPU_WORK_BATCH queued items.
809 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
811 int cpu
= hctx
->next_cpu
;
813 if (--hctx
->next_cpu_batch
<= 0) {
816 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
817 if (next_cpu
>= nr_cpu_ids
)
818 next_cpu
= cpumask_first(hctx
->cpumask
);
820 hctx
->next_cpu
= next_cpu
;
821 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
827 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
829 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
832 if (!async
&& cpumask_test_cpu(smp_processor_id(), hctx
->cpumask
))
833 __blk_mq_run_hw_queue(hctx
);
834 else if (hctx
->queue
->nr_hw_queues
== 1)
835 kblockd_schedule_delayed_work(&hctx
->run_work
, 0);
839 cpu
= blk_mq_hctx_next_cpu(hctx
);
840 kblockd_schedule_delayed_work_on(cpu
, &hctx
->run_work
, 0);
844 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
846 struct blk_mq_hw_ctx
*hctx
;
849 queue_for_each_hw_ctx(q
, hctx
, i
) {
850 if ((!blk_mq_hctx_has_pending(hctx
) &&
851 list_empty_careful(&hctx
->dispatch
)) ||
852 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
856 blk_mq_run_hw_queue(hctx
, async
);
860 EXPORT_SYMBOL(blk_mq_run_queues
);
862 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
864 cancel_delayed_work(&hctx
->run_work
);
865 cancel_delayed_work(&hctx
->delay_work
);
866 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
868 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
870 void blk_mq_stop_hw_queues(struct request_queue
*q
)
872 struct blk_mq_hw_ctx
*hctx
;
875 queue_for_each_hw_ctx(q
, hctx
, i
)
876 blk_mq_stop_hw_queue(hctx
);
878 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
880 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
882 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
885 __blk_mq_run_hw_queue(hctx
);
888 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
890 void blk_mq_start_hw_queues(struct request_queue
*q
)
892 struct blk_mq_hw_ctx
*hctx
;
895 queue_for_each_hw_ctx(q
, hctx
, i
)
896 blk_mq_start_hw_queue(hctx
);
898 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
901 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
903 struct blk_mq_hw_ctx
*hctx
;
906 queue_for_each_hw_ctx(q
, hctx
, i
) {
907 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
910 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
912 blk_mq_run_hw_queue(hctx
, async
);
916 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
918 static void blk_mq_run_work_fn(struct work_struct
*work
)
920 struct blk_mq_hw_ctx
*hctx
;
922 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
924 __blk_mq_run_hw_queue(hctx
);
927 static void blk_mq_delay_work_fn(struct work_struct
*work
)
929 struct blk_mq_hw_ctx
*hctx
;
931 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
933 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
934 __blk_mq_run_hw_queue(hctx
);
937 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
939 unsigned long tmo
= msecs_to_jiffies(msecs
);
941 if (hctx
->queue
->nr_hw_queues
== 1)
942 kblockd_schedule_delayed_work(&hctx
->delay_work
, tmo
);
946 cpu
= blk_mq_hctx_next_cpu(hctx
);
947 kblockd_schedule_delayed_work_on(cpu
, &hctx
->delay_work
, tmo
);
950 EXPORT_SYMBOL(blk_mq_delay_queue
);
952 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
953 struct request
*rq
, bool at_head
)
955 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
957 trace_block_rq_insert(hctx
->queue
, rq
);
960 list_add(&rq
->queuelist
, &ctx
->rq_list
);
962 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
964 blk_mq_hctx_mark_pending(hctx
, ctx
);
967 * We do this early, to ensure we are on the right CPU.
972 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
975 struct request_queue
*q
= rq
->q
;
976 struct blk_mq_hw_ctx
*hctx
;
977 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
979 current_ctx
= blk_mq_get_ctx(q
);
980 if (!cpu_online(ctx
->cpu
))
981 rq
->mq_ctx
= ctx
= current_ctx
;
983 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
985 if (rq
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
) &&
986 !(rq
->cmd_flags
& (REQ_FLUSH_SEQ
))) {
987 blk_insert_flush(rq
);
989 spin_lock(&ctx
->lock
);
990 __blk_mq_insert_request(hctx
, rq
, at_head
);
991 spin_unlock(&ctx
->lock
);
995 blk_mq_run_hw_queue(hctx
, async
);
997 blk_mq_put_ctx(current_ctx
);
1000 static void blk_mq_insert_requests(struct request_queue
*q
,
1001 struct blk_mq_ctx
*ctx
,
1002 struct list_head
*list
,
1007 struct blk_mq_hw_ctx
*hctx
;
1008 struct blk_mq_ctx
*current_ctx
;
1010 trace_block_unplug(q
, depth
, !from_schedule
);
1012 current_ctx
= blk_mq_get_ctx(q
);
1014 if (!cpu_online(ctx
->cpu
))
1016 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1019 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1022 spin_lock(&ctx
->lock
);
1023 while (!list_empty(list
)) {
1026 rq
= list_first_entry(list
, struct request
, queuelist
);
1027 list_del_init(&rq
->queuelist
);
1029 __blk_mq_insert_request(hctx
, rq
, false);
1031 spin_unlock(&ctx
->lock
);
1033 blk_mq_run_hw_queue(hctx
, from_schedule
);
1034 blk_mq_put_ctx(current_ctx
);
1037 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1039 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1040 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1042 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1043 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1044 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1047 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1049 struct blk_mq_ctx
*this_ctx
;
1050 struct request_queue
*this_q
;
1053 LIST_HEAD(ctx_list
);
1056 list_splice_init(&plug
->mq_list
, &list
);
1058 list_sort(NULL
, &list
, plug_ctx_cmp
);
1064 while (!list_empty(&list
)) {
1065 rq
= list_entry_rq(list
.next
);
1066 list_del_init(&rq
->queuelist
);
1068 if (rq
->mq_ctx
!= this_ctx
) {
1070 blk_mq_insert_requests(this_q
, this_ctx
,
1075 this_ctx
= rq
->mq_ctx
;
1081 list_add_tail(&rq
->queuelist
, &ctx_list
);
1085 * If 'this_ctx' is set, we know we have entries to complete
1086 * on 'ctx_list'. Do those.
1089 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1094 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1096 init_request_from_bio(rq
, bio
);
1098 if (blk_do_io_stat(rq
)) {
1099 rq
->start_time
= jiffies
;
1100 blk_account_io_start(rq
, 1);
1104 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1105 struct blk_mq_ctx
*ctx
,
1106 struct request
*rq
, struct bio
*bio
)
1108 struct request_queue
*q
= hctx
->queue
;
1110 if (!(hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
)) {
1111 blk_mq_bio_to_request(rq
, bio
);
1112 spin_lock(&ctx
->lock
);
1114 __blk_mq_insert_request(hctx
, rq
, false);
1115 spin_unlock(&ctx
->lock
);
1118 spin_lock(&ctx
->lock
);
1119 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1120 blk_mq_bio_to_request(rq
, bio
);
1124 spin_unlock(&ctx
->lock
);
1125 __blk_mq_free_request(hctx
, ctx
, rq
);
1130 struct blk_map_ctx
{
1131 struct blk_mq_hw_ctx
*hctx
;
1132 struct blk_mq_ctx
*ctx
;
1135 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1137 struct blk_map_ctx
*data
)
1139 struct blk_mq_hw_ctx
*hctx
;
1140 struct blk_mq_ctx
*ctx
;
1142 int rw
= bio_data_dir(bio
);
1143 struct blk_mq_alloc_data alloc_data
;
1145 if (unlikely(blk_mq_queue_enter(q
))) {
1146 bio_endio(bio
, -EIO
);
1150 ctx
= blk_mq_get_ctx(q
);
1151 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1153 if (rw_is_sync(bio
->bi_rw
))
1156 trace_block_getrq(q
, bio
, rw
);
1157 blk_mq_set_alloc_data(&alloc_data
, q
, GFP_ATOMIC
, false, ctx
,
1159 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1160 if (unlikely(!rq
)) {
1161 __blk_mq_run_hw_queue(hctx
);
1162 blk_mq_put_ctx(ctx
);
1163 trace_block_sleeprq(q
, bio
, rw
);
1165 ctx
= blk_mq_get_ctx(q
);
1166 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1167 blk_mq_set_alloc_data(&alloc_data
, q
,
1168 __GFP_WAIT
|GFP_ATOMIC
, false, ctx
, hctx
);
1169 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1170 ctx
= alloc_data
.ctx
;
1171 hctx
= alloc_data
.hctx
;
1181 * Multiple hardware queue variant. This will not use per-process plugs,
1182 * but will attempt to bypass the hctx queueing if we can go straight to
1183 * hardware for SYNC IO.
1185 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1187 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1188 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1189 struct blk_map_ctx data
;
1192 blk_queue_bounce(q
, &bio
);
1194 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1195 bio_endio(bio
, -EIO
);
1199 rq
= blk_mq_map_request(q
, bio
, &data
);
1203 if (unlikely(is_flush_fua
)) {
1204 blk_mq_bio_to_request(rq
, bio
);
1205 blk_insert_flush(rq
);
1212 blk_mq_bio_to_request(rq
, bio
);
1213 blk_mq_start_request(rq
, true);
1217 * For OK queue, we are done. For error, kill it. Any other
1218 * error (busy), just add it to our list as we previously
1221 ret
= q
->mq_ops
->queue_rq(data
.hctx
, rq
);
1222 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1225 __blk_mq_requeue_request(rq
);
1227 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1229 blk_mq_end_io(rq
, rq
->errors
);
1235 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1237 * For a SYNC request, send it to the hardware immediately. For
1238 * an ASYNC request, just ensure that we run it later on. The
1239 * latter allows for merging opportunities and more efficient
1243 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1246 blk_mq_put_ctx(data
.ctx
);
1250 * Single hardware queue variant. This will attempt to use any per-process
1251 * plug for merging and IO deferral.
1253 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1255 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1256 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1257 unsigned int use_plug
, request_count
= 0;
1258 struct blk_map_ctx data
;
1262 * If we have multiple hardware queues, just go directly to
1263 * one of those for sync IO.
1265 use_plug
= !is_flush_fua
&& !is_sync
;
1267 blk_queue_bounce(q
, &bio
);
1269 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1270 bio_endio(bio
, -EIO
);
1274 if (use_plug
&& !blk_queue_nomerges(q
) &&
1275 blk_attempt_plug_merge(q
, bio
, &request_count
))
1278 rq
= blk_mq_map_request(q
, bio
, &data
);
1282 if (unlikely(is_flush_fua
)) {
1283 blk_mq_bio_to_request(rq
, bio
);
1284 blk_insert_flush(rq
);
1289 * A task plug currently exists. Since this is completely lockless,
1290 * utilize that to temporarily store requests until the task is
1291 * either done or scheduled away.
1294 struct blk_plug
*plug
= current
->plug
;
1297 blk_mq_bio_to_request(rq
, bio
);
1298 if (list_empty(&plug
->mq_list
))
1299 trace_block_plug(q
);
1300 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1301 blk_flush_plug_list(plug
, false);
1302 trace_block_plug(q
);
1304 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1305 blk_mq_put_ctx(data
.ctx
);
1310 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1312 * For a SYNC request, send it to the hardware immediately. For
1313 * an ASYNC request, just ensure that we run it later on. The
1314 * latter allows for merging opportunities and more efficient
1318 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1321 blk_mq_put_ctx(data
.ctx
);
1325 * Default mapping to a software queue, since we use one per CPU.
1327 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1329 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1331 EXPORT_SYMBOL(blk_mq_map_queue
);
1333 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1334 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1338 if (tags
->rqs
&& set
->ops
->exit_request
) {
1341 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1344 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1349 while (!list_empty(&tags
->page_list
)) {
1350 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1351 list_del_init(&page
->lru
);
1352 __free_pages(page
, page
->private);
1357 blk_mq_free_tags(tags
);
1360 static size_t order_to_size(unsigned int order
)
1362 return (size_t)PAGE_SIZE
<< order
;
1365 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1366 unsigned int hctx_idx
)
1368 struct blk_mq_tags
*tags
;
1369 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1370 size_t rq_size
, left
;
1372 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1377 INIT_LIST_HEAD(&tags
->page_list
);
1379 tags
->rqs
= kmalloc_node(set
->queue_depth
* sizeof(struct request
*),
1380 GFP_KERNEL
, set
->numa_node
);
1382 blk_mq_free_tags(tags
);
1387 * rq_size is the size of the request plus driver payload, rounded
1388 * to the cacheline size
1390 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1392 left
= rq_size
* set
->queue_depth
;
1394 for (i
= 0; i
< set
->queue_depth
; ) {
1395 int this_order
= max_order
;
1400 while (left
< order_to_size(this_order
- 1) && this_order
)
1404 page
= alloc_pages_node(set
->numa_node
, GFP_KERNEL
,
1410 if (order_to_size(this_order
) < rq_size
)
1417 page
->private = this_order
;
1418 list_add_tail(&page
->lru
, &tags
->page_list
);
1420 p
= page_address(page
);
1421 entries_per_page
= order_to_size(this_order
) / rq_size
;
1422 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1423 left
-= to_do
* rq_size
;
1424 for (j
= 0; j
< to_do
; j
++) {
1426 if (set
->ops
->init_request
) {
1427 if (set
->ops
->init_request(set
->driver_data
,
1428 tags
->rqs
[i
], hctx_idx
, i
,
1441 pr_warn("%s: failed to allocate requests\n", __func__
);
1442 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1446 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1451 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1453 unsigned int bpw
= 8, total
, num_maps
, i
;
1455 bitmap
->bits_per_word
= bpw
;
1457 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1458 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1463 bitmap
->map_size
= num_maps
;
1466 for (i
= 0; i
< num_maps
; i
++) {
1467 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1468 total
-= bitmap
->map
[i
].depth
;
1474 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1476 struct request_queue
*q
= hctx
->queue
;
1477 struct blk_mq_ctx
*ctx
;
1481 * Move ctx entries to new CPU, if this one is going away.
1483 ctx
= __blk_mq_get_ctx(q
, cpu
);
1485 spin_lock(&ctx
->lock
);
1486 if (!list_empty(&ctx
->rq_list
)) {
1487 list_splice_init(&ctx
->rq_list
, &tmp
);
1488 blk_mq_hctx_clear_pending(hctx
, ctx
);
1490 spin_unlock(&ctx
->lock
);
1492 if (list_empty(&tmp
))
1495 ctx
= blk_mq_get_ctx(q
);
1496 spin_lock(&ctx
->lock
);
1498 while (!list_empty(&tmp
)) {
1501 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1503 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1506 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1507 blk_mq_hctx_mark_pending(hctx
, ctx
);
1509 spin_unlock(&ctx
->lock
);
1511 blk_mq_run_hw_queue(hctx
, true);
1512 blk_mq_put_ctx(ctx
);
1516 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1518 struct request_queue
*q
= hctx
->queue
;
1519 struct blk_mq_tag_set
*set
= q
->tag_set
;
1521 if (set
->tags
[hctx
->queue_num
])
1524 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1525 if (!set
->tags
[hctx
->queue_num
])
1528 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1532 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1535 struct blk_mq_hw_ctx
*hctx
= data
;
1537 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1538 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1539 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1540 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1545 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1546 struct blk_mq_tag_set
*set
, int nr_queue
)
1548 struct blk_mq_hw_ctx
*hctx
;
1551 queue_for_each_hw_ctx(q
, hctx
, i
) {
1555 if (set
->ops
->exit_hctx
)
1556 set
->ops
->exit_hctx(hctx
, i
);
1558 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1560 blk_mq_free_bitmap(&hctx
->ctx_map
);
1565 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1566 struct blk_mq_tag_set
*set
)
1568 struct blk_mq_hw_ctx
*hctx
;
1571 queue_for_each_hw_ctx(q
, hctx
, i
) {
1572 free_cpumask_var(hctx
->cpumask
);
1577 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1578 struct blk_mq_tag_set
*set
)
1580 struct blk_mq_hw_ctx
*hctx
;
1584 * Initialize hardware queues
1586 queue_for_each_hw_ctx(q
, hctx
, i
) {
1589 node
= hctx
->numa_node
;
1590 if (node
== NUMA_NO_NODE
)
1591 node
= hctx
->numa_node
= set
->numa_node
;
1593 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1594 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1595 spin_lock_init(&hctx
->lock
);
1596 INIT_LIST_HEAD(&hctx
->dispatch
);
1598 hctx
->queue_num
= i
;
1599 hctx
->flags
= set
->flags
;
1600 hctx
->cmd_size
= set
->cmd_size
;
1602 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1603 blk_mq_hctx_notify
, hctx
);
1604 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1606 hctx
->tags
= set
->tags
[i
];
1609 * Allocate space for all possible cpus to avoid allocation in
1612 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1617 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1622 if (set
->ops
->init_hctx
&&
1623 set
->ops
->init_hctx(hctx
, set
->driver_data
, i
))
1627 if (i
== q
->nr_hw_queues
)
1633 blk_mq_exit_hw_queues(q
, set
, i
);
1638 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1639 unsigned int nr_hw_queues
)
1643 for_each_possible_cpu(i
) {
1644 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1645 struct blk_mq_hw_ctx
*hctx
;
1647 memset(__ctx
, 0, sizeof(*__ctx
));
1649 spin_lock_init(&__ctx
->lock
);
1650 INIT_LIST_HEAD(&__ctx
->rq_list
);
1653 /* If the cpu isn't online, the cpu is mapped to first hctx */
1657 hctx
= q
->mq_ops
->map_queue(q
, i
);
1658 cpumask_set_cpu(i
, hctx
->cpumask
);
1662 * Set local node, IFF we have more than one hw queue. If
1663 * not, we remain on the home node of the device
1665 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1666 hctx
->numa_node
= cpu_to_node(i
);
1670 static void blk_mq_map_swqueue(struct request_queue
*q
)
1673 struct blk_mq_hw_ctx
*hctx
;
1674 struct blk_mq_ctx
*ctx
;
1676 queue_for_each_hw_ctx(q
, hctx
, i
) {
1677 cpumask_clear(hctx
->cpumask
);
1682 * Map software to hardware queues
1684 queue_for_each_ctx(q
, ctx
, i
) {
1685 /* If the cpu isn't online, the cpu is mapped to first hctx */
1689 hctx
= q
->mq_ops
->map_queue(q
, i
);
1690 cpumask_set_cpu(i
, hctx
->cpumask
);
1691 ctx
->index_hw
= hctx
->nr_ctx
;
1692 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1695 queue_for_each_hw_ctx(q
, hctx
, i
) {
1697 * If not software queues are mapped to this hardware queue,
1698 * disable it and free the request entries
1700 if (!hctx
->nr_ctx
) {
1701 struct blk_mq_tag_set
*set
= q
->tag_set
;
1704 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1705 set
->tags
[i
] = NULL
;
1712 * Initialize batch roundrobin counts
1714 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1715 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1719 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1721 struct blk_mq_hw_ctx
*hctx
;
1722 struct request_queue
*q
;
1726 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1731 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1732 blk_mq_freeze_queue(q
);
1734 queue_for_each_hw_ctx(q
, hctx
, i
) {
1736 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1738 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1740 blk_mq_unfreeze_queue(q
);
1744 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1746 struct blk_mq_tag_set
*set
= q
->tag_set
;
1748 blk_mq_freeze_queue(q
);
1750 mutex_lock(&set
->tag_list_lock
);
1751 list_del_init(&q
->tag_set_list
);
1752 blk_mq_update_tag_set_depth(set
);
1753 mutex_unlock(&set
->tag_list_lock
);
1755 blk_mq_unfreeze_queue(q
);
1758 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1759 struct request_queue
*q
)
1763 mutex_lock(&set
->tag_list_lock
);
1764 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1765 blk_mq_update_tag_set_depth(set
);
1766 mutex_unlock(&set
->tag_list_lock
);
1769 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1771 struct blk_mq_hw_ctx
**hctxs
;
1772 struct blk_mq_ctx __percpu
*ctx
;
1773 struct request_queue
*q
;
1777 ctx
= alloc_percpu(struct blk_mq_ctx
);
1779 return ERR_PTR(-ENOMEM
);
1781 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1787 map
= blk_mq_make_queue_map(set
);
1791 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1792 int node
= blk_mq_hw_queue_to_node(map
, i
);
1794 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
1799 if (!zalloc_cpumask_var(&hctxs
[i
]->cpumask
, GFP_KERNEL
))
1802 atomic_set(&hctxs
[i
]->nr_active
, 0);
1803 hctxs
[i
]->numa_node
= node
;
1804 hctxs
[i
]->queue_num
= i
;
1807 q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1811 if (percpu_counter_init(&q
->mq_usage_counter
, 0))
1814 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1815 blk_queue_rq_timeout(q
, 30000);
1817 q
->nr_queues
= nr_cpu_ids
;
1818 q
->nr_hw_queues
= set
->nr_hw_queues
;
1822 q
->queue_hw_ctx
= hctxs
;
1824 q
->mq_ops
= set
->ops
;
1825 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1827 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
1828 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
1830 q
->sg_reserved_size
= INT_MAX
;
1832 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
1833 INIT_LIST_HEAD(&q
->requeue_list
);
1834 spin_lock_init(&q
->requeue_lock
);
1836 if (q
->nr_hw_queues
> 1)
1837 blk_queue_make_request(q
, blk_mq_make_request
);
1839 blk_queue_make_request(q
, blk_sq_make_request
);
1841 blk_queue_rq_timed_out(q
, blk_mq_rq_timed_out
);
1843 blk_queue_rq_timeout(q
, set
->timeout
);
1846 * Do this after blk_queue_make_request() overrides it...
1848 q
->nr_requests
= set
->queue_depth
;
1850 if (set
->ops
->complete
)
1851 blk_queue_softirq_done(q
, set
->ops
->complete
);
1853 blk_mq_init_flush(q
);
1854 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
1856 q
->flush_rq
= kzalloc(round_up(sizeof(struct request
) +
1857 set
->cmd_size
, cache_line_size()),
1862 if (blk_mq_init_hw_queues(q
, set
))
1865 mutex_lock(&all_q_mutex
);
1866 list_add_tail(&q
->all_q_node
, &all_q_list
);
1867 mutex_unlock(&all_q_mutex
);
1869 blk_mq_add_queue_tag_set(set
, q
);
1871 blk_mq_map_swqueue(q
);
1878 blk_cleanup_queue(q
);
1881 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1884 free_cpumask_var(hctxs
[i
]->cpumask
);
1891 return ERR_PTR(-ENOMEM
);
1893 EXPORT_SYMBOL(blk_mq_init_queue
);
1895 void blk_mq_free_queue(struct request_queue
*q
)
1897 struct blk_mq_tag_set
*set
= q
->tag_set
;
1899 blk_mq_del_queue_tag_set(q
);
1901 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1902 blk_mq_free_hw_queues(q
, set
);
1904 percpu_counter_destroy(&q
->mq_usage_counter
);
1906 free_percpu(q
->queue_ctx
);
1907 kfree(q
->queue_hw_ctx
);
1910 q
->queue_ctx
= NULL
;
1911 q
->queue_hw_ctx
= NULL
;
1914 mutex_lock(&all_q_mutex
);
1915 list_del_init(&q
->all_q_node
);
1916 mutex_unlock(&all_q_mutex
);
1919 /* Basically redo blk_mq_init_queue with queue frozen */
1920 static void blk_mq_queue_reinit(struct request_queue
*q
)
1922 blk_mq_freeze_queue(q
);
1924 blk_mq_sysfs_unregister(q
);
1926 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1929 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1930 * we should change hctx numa_node according to new topology (this
1931 * involves free and re-allocate memory, worthy doing?)
1934 blk_mq_map_swqueue(q
);
1936 blk_mq_sysfs_register(q
);
1938 blk_mq_unfreeze_queue(q
);
1941 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1942 unsigned long action
, void *hcpu
)
1944 struct request_queue
*q
;
1947 * Before new mappings are established, hotadded cpu might already
1948 * start handling requests. This doesn't break anything as we map
1949 * offline CPUs to first hardware queue. We will re-init the queue
1950 * below to get optimal settings.
1952 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1953 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1956 mutex_lock(&all_q_mutex
);
1957 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1958 blk_mq_queue_reinit(q
);
1959 mutex_unlock(&all_q_mutex
);
1963 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
1967 if (!set
->nr_hw_queues
)
1969 if (!set
->queue_depth
|| set
->queue_depth
> BLK_MQ_MAX_DEPTH
)
1971 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
1974 if (!set
->nr_hw_queues
|| !set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
1978 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
1979 sizeof(struct blk_mq_tags
*),
1980 GFP_KERNEL
, set
->numa_node
);
1984 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1985 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
1990 mutex_init(&set
->tag_list_lock
);
1991 INIT_LIST_HEAD(&set
->tag_list
);
1997 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2001 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2003 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2007 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2009 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2014 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2016 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2018 struct blk_mq_tag_set
*set
= q
->tag_set
;
2019 struct blk_mq_hw_ctx
*hctx
;
2022 if (!set
|| nr
> set
->queue_depth
)
2026 queue_for_each_hw_ctx(q
, hctx
, i
) {
2027 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2033 q
->nr_requests
= nr
;
2038 void blk_mq_disable_hotplug(void)
2040 mutex_lock(&all_q_mutex
);
2043 void blk_mq_enable_hotplug(void)
2045 mutex_unlock(&all_q_mutex
);
2048 static int __init
blk_mq_init(void)
2052 /* Must be called after percpu_counter_hotcpu_callback() */
2053 hotcpu_notifier(blk_mq_queue_reinit_notify
, -10);
2057 subsys_initcall(blk_mq_init
);