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authorJens Axboe <axboe@kernel.dk>2018-10-29 22:25:27 +0300
committerJens Axboe <axboe@kernel.dk>2018-11-07 23:44:59 +0300
commit392546aed22009060911f76b6ea24520e2f8b50f (patch)
treed0277e8fe433b046a5d72d8ffb739db2bc1b3012 /block/blk-mq.c
parentb3c661b15d5ab11d982e58bee23e05c1780528a1 (diff)
downloadlinux-392546aed22009060911f76b6ea24520e2f8b50f.tar.xz
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: 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>
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r--block/blk-mq.c28
1 files changed, 21 insertions, 7 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 2e730c95513f..ccf135cf41b0 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -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;