When tag space of one device is big enough, we use hw tag directly for I/O scheduling.
Now the decision is made if hw queue depth is not less than q->nr_requests and the tag set isn't shared. Signed-off-by: Ming Lei <[email protected]> --- block/blk-mq-sched.c | 80 +++++++++++++++++++++++++++++++++++++++++++++----- block/blk-mq-sched.h | 8 +++++ block/blk-mq.c | 35 ++++++++++++++++++++-- include/linux/blkdev.h | 8 +++++ 4 files changed, 122 insertions(+), 9 deletions(-) diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 2c5981ff9e04..a7e125a40e0a 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -417,9 +417,9 @@ void blk_mq_sched_insert_requests(struct request_queue *q, blk_mq_run_hw_queue(hctx, run_queue_async); } -static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set, - struct blk_mq_hw_ctx *hctx, - unsigned int hctx_idx) +void blk_mq_sched_free_tags(struct blk_mq_tag_set *set, + struct blk_mq_hw_ctx *hctx, + unsigned int hctx_idx) { if (hctx->sched_tags) { blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx); @@ -428,9 +428,9 @@ static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set, } } -static int blk_mq_sched_alloc_tags(struct request_queue *q, - struct blk_mq_hw_ctx *hctx, - unsigned int hctx_idx) +int blk_mq_sched_alloc_tags(struct request_queue *q, + struct blk_mq_hw_ctx *hctx, + unsigned int hctx_idx) { struct blk_mq_tag_set *set = q->tag_set; int ret; @@ -450,14 +450,52 @@ static int blk_mq_sched_alloc_tags(struct request_queue *q, return ret; } +static int blk_mq_set_queue_depth(struct blk_mq_hw_ctx *hctx, + unsigned int nr) +{ + if (!hctx->tags) + return -EINVAL; + + return blk_mq_tag_update_depth(hctx, &hctx->tags, nr, false); +} + +static int blk_mq_set_queues_depth(struct request_queue *q, + unsigned int nr) +{ + struct blk_mq_hw_ctx *hctx; + int i, j, ret; + + queue_for_each_hw_ctx(q, hctx, i) { + ret = blk_mq_set_queue_depth(hctx, nr); + if (ret) + goto recovery; + } + return 0; + + recovery: + queue_for_each_hw_ctx(q, hctx, j) { + if (j >= i) + break; + blk_mq_tag_update_depth(hctx, &hctx->tags, + q->act_hw_queue_depth, + false); + } + return ret; +} + static void blk_mq_sched_tags_teardown(struct request_queue *q) { struct blk_mq_tag_set *set = q->tag_set; struct blk_mq_hw_ctx *hctx; int i; - queue_for_each_hw_ctx(q, hctx, i) + queue_for_each_hw_ctx(q, hctx, i) { + if (hctx->flags & BLK_MQ_F_SCHED_USE_HW_TAG) { + blk_mq_set_queue_depth(hctx, q->act_hw_queue_depth); + hctx->flags &= ~BLK_MQ_F_SCHED_USE_HW_TAG; + } blk_mq_sched_free_tags(set, hctx, i); + } } int blk_mq_sched_init_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx, @@ -504,12 +542,28 @@ void blk_mq_sched_exit_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx, blk_mq_sched_free_tags(q->tag_set, hctx, hctx_idx); } +/* + * If this queue has enough hardware tags and doesn't share tags with + * other queues, just use hw tag directly for scheduling. + */ +bool blk_mq_sched_may_use_hw_tag(struct request_queue *q) +{ + if (q->tag_set->flags & BLK_MQ_F_TAG_SHARED) + return false; + + if (q->act_hw_queue_depth < q->nr_requests) + return false; + + return true; +} + int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e) { struct blk_mq_hw_ctx *hctx; struct elevator_queue *eq; unsigned int i; int ret; + bool auto_hw_tag; if (!e) { q->elevator = NULL; @@ -522,7 +576,19 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e) */ q->nr_requests = 2 * BLKDEV_MAX_RQ; + auto_hw_tag = blk_mq_sched_may_use_hw_tag(q); + if (auto_hw_tag) { + q->act_hw_queue_depth = blk_mq_get_queue_depth(q); + if (blk_mq_set_queues_depth(q, q->nr_requests)) + auto_hw_tag = false; + } + queue_for_each_hw_ctx(q, hctx, i) { + if (auto_hw_tag) + hctx->flags |= BLK_MQ_F_SCHED_USE_HW_TAG; + else + hctx->flags &= ~BLK_MQ_F_SCHED_USE_HW_TAG; + ret = blk_mq_sched_alloc_tags(q, hctx, i); if (ret) goto err; diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h index edafb5383b7b..bbfc1ea5fafa 100644 --- a/block/blk-mq-sched.h +++ b/block/blk-mq-sched.h @@ -25,6 +25,7 @@ void blk_mq_sched_insert_requests(struct request_queue *q, void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx); +bool blk_mq_sched_may_use_hw_tag(struct request_queue *q); int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e); void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e); @@ -35,6 +36,13 @@ void blk_mq_sched_exit_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx, int blk_mq_sched_init(struct request_queue *q); +void blk_mq_sched_free_tags(struct blk_mq_tag_set *set, + struct blk_mq_hw_ctx *hctx, + unsigned int hctx_idx); +int blk_mq_sched_alloc_tags(struct request_queue *q, + struct blk_mq_hw_ctx *hctx, + unsigned int hctx_idx); + static inline bool blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio) { diff --git a/block/blk-mq.c b/block/blk-mq.c index 1a61ca611fae..e02fa8d078e6 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2150,6 +2150,34 @@ int blk_mq_get_queue_depth(struct request_queue *q) return tags->bitmap_tags.sb.depth + tags->breserved_tags.sb.depth; } +static void blk_mq_update_sched_flag(struct request_queue *q) +{ + struct blk_mq_hw_ctx *hctx; + int i; + + if (!q->elevator) + return; + + if (!blk_mq_sched_may_use_hw_tag(q)) + queue_for_each_hw_ctx(q, hctx, i) { + if (hctx->flags & BLK_MQ_F_SCHED_USE_HW_TAG) { + blk_mq_set_queue_depth(hctx, q->act_hw_queue_depth); + hctx->flags &= ~BLK_MQ_F_SCHED_USE_HW_TAG; + } + if (!hctx->sched_tags) { + if (blk_mq_sched_alloc_tags(q, hctx, i)) + goto force_use_hw_tag; + } + } + else + force_use_hw_tag: + queue_for_each_hw_ctx(q, hctx, i) { + hctx->flags |= BLK_MQ_F_SCHED_USE_HW_TAG; + if (hctx->sched_tags) + blk_mq_sched_free_tags(q->tag_set, hctx, i); + } +} + static void queue_set_hctx_shared(struct request_queue *q, bool shared) { struct blk_mq_hw_ctx *hctx; @@ -2366,7 +2394,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, /* * Do this after blk_queue_make_request() overrides it... */ - q->nr_requests = set->queue_depth; + q->act_hw_queue_depth = q->nr_requests = set->queue_depth; /* * Default to classic polling @@ -2689,8 +2717,11 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) break; } - if (!ret) + if (!ret) { q->nr_requests = nr; + q->act_hw_queue_depth = blk_mq_get_queue_depth(q); + blk_mq_update_sched_flag(q); + } blk_mq_unfreeze_queue(q); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index b5d1e27631ee..7389e388d583 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -428,6 +428,14 @@ struct request_queue { unsigned int nr_hw_queues; /* + * save active hw queue depth before using hw tag for scheduling, + * this need to revisit if per hw queue depth is supported. + * + * Only used by blk-mq-sched. + */ + unsigned int act_hw_queue_depth; + + /* * Dispatch queue sorting */ sector_t end_sector; -- 2.9.3
