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blk-mq: separate number of hardware queues from nr_cpu_ids

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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: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2018-10-29 13:25:27 -06:00
parent b3c661b15d
commit 392546aed2
1 changed files with 21 additions and 7 deletions
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28
block/blk-mq.c
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@ -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;