Commit 392546ae authored by Jens Axboe's avatar Jens Axboe
Browse files

blk-mq: separate number of hardware queues from nr_cpu_ids 



With multiple maps, nr_cpu_ids is no longer the maximum number of
hardware queues we support on a given devices. The initializer of
the tag_set can have set ->nr_hw_queues larger than the available
number of CPUs, since we can exceed that with multiple queue maps.

Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Reviewed-by: default avatarKeith Busch <keith.busch@intel.com>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b3c661b1

block/blk-mq.c

+21 −7
Original line number Diff line number Diff line
@@ -2669,6 +2669,19 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, 
	mutex_unlock(&q->sysfs_lock);

}



/*

 * Maximum number of hardware queues we support. For single sets, we'll never

 * have more than the CPUs (software queues). For multiple sets, the tag_set

 * user may have set ->nr_hw_queues larger.

 */

static unsigned int nr_hw_queues(struct blk_mq_tag_set *set)

{

	if (set->nr_maps == 1)

		return nr_cpu_ids;



	return max(set->nr_hw_queues, nr_cpu_ids);

}



struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,

						  struct request_queue *q)

{
@@ -2688,7 +2701,8 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, 
	/* init q->mq_kobj and sw queues' kobjects */

	blk_mq_sysfs_init(q);



	q->queue_hw_ctx = kcalloc_node(nr_cpu_ids, sizeof(*(q->queue_hw_ctx)),

	q->nr_queues = nr_hw_queues(set);

	q->queue_hw_ctx = kcalloc_node(q->nr_queues, sizeof(*(q->queue_hw_ctx)),

						GFP_KERNEL, set->numa_node);

	if (!q->queue_hw_ctx)

		goto err_percpu;
@@ -2700,7 +2714,6 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, 
	INIT_WORK(&q->timeout_work, blk_mq_timeout_work);

	blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);



	q->nr_queues = nr_cpu_ids;

	q->tag_set = set;



	q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
@@ -2887,12 +2900,13 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) 
		set->queue_depth = min(64U, set->queue_depth);

	}

	/*

	 * There is no use for more h/w queues than cpus.

	 * There is no use for more h/w queues than cpus if we just have

	 * a single map

	 */

	if (set->nr_hw_queues > nr_cpu_ids)

	if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)

		set->nr_hw_queues = nr_cpu_ids;



	set->tags = kcalloc_node(nr_cpu_ids, sizeof(struct blk_mq_tags *),

	set->tags = kcalloc_node(nr_hw_queues(set), sizeof(struct blk_mq_tags *),

				 GFP_KERNEL, set->numa_node);

	if (!set->tags)

		return -ENOMEM;
@@ -2935,7 +2949,7 @@ void blk_mq_free_tag_set(struct blk_mq_tag_set *set) 
{

	int i, j;



	for (i = 0; i < nr_cpu_ids; i++)

	for (i = 0; i < nr_hw_queues(set); i++)

		blk_mq_free_map_and_requests(set, i);



	for (j = 0; j < set->nr_maps; j++) {
@@ -3067,7 +3081,7 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, 


	lockdep_assert_held(&set->tag_list_lock);



	if (nr_hw_queues > nr_cpu_ids)

	if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)

		nr_hw_queues = nr_cpu_ids;

	if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues)

		return;

CRA Git | Maintained and supported by SUSTech CRA and CCSE