diff options
Diffstat (limited to 'block/blk-mq.h')
| -rw-r--r-- | block/blk-mq.h | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/block/blk-mq.h b/block/blk-mq.h index 3acdb56065e1..56dc37c21908 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -259,4 +259,36 @@ static inline struct blk_plug *blk_mq_plug(struct request_queue *q, return NULL; } +/* + * For shared tag users, we track the number of currently active users + * and attempt to provide a fair share of the tag depth for each of them. + */ +static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx, + struct sbitmap_queue *bt) +{ + unsigned int depth, users; + + if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) + return true; + if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) + return true; + + /* + * Don't try dividing an ant + */ + if (bt->sb.depth == 1) + return true; + + users = atomic_read(&hctx->tags->active_queues); + if (!users) + return true; + + /* + * Allow at least some tags + */ + depth = max((bt->sb.depth + users - 1) / users, 4U); + return atomic_read(&hctx->nr_active) < depth; +} + + #endif |