[PATCH 01/14] block: inline fast path of driver tag allocation
From: Jens Axboe <axboe@kernel.dk>
Date: 2021-10-17 01:37:54
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
If we don't use an IO scheduler or have shared tags, then we don't need to call into this external function at all. This saves ~2% for such a setup. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- block/blk-mq.c | 8 +++----- block/blk-mq.h | 15 ++++++++++++++- 2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 1bbe5de66c40..90bc93fe373e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c@@ -1145,7 +1145,7 @@ static inline unsigned int queued_to_index(unsigned int queued) return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1); } -static bool __blk_mq_get_driver_tag(struct request *rq) +static bool __blk_mq_alloc_driver_tag(struct request *rq) { struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags; unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
@@ -1169,11 +1169,9 @@ static bool __blk_mq_get_driver_tag(struct request *rq) return true; } -bool blk_mq_get_driver_tag(struct request *rq) +bool __blk_mq_get_driver_tag(struct blk_mq_hw_ctx *hctx, struct request *rq) { - struct blk_mq_hw_ctx *hctx = rq->mq_hctx; - - if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_get_driver_tag(rq)) + if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_alloc_driver_tag(rq)) return false; if ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 8be447995106..ceed0a001c76 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h@@ -264,7 +264,20 @@ static inline void blk_mq_put_driver_tag(struct request *rq) __blk_mq_put_driver_tag(rq->mq_hctx, rq); } -bool blk_mq_get_driver_tag(struct request *rq); +bool __blk_mq_get_driver_tag(struct blk_mq_hw_ctx *hctx, struct request *rq); + +static inline bool blk_mq_get_driver_tag(struct request *rq) +{ + struct blk_mq_hw_ctx *hctx = rq->mq_hctx; + + if (rq->tag != BLK_MQ_NO_TAG && + !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) { + hctx->tags->rqs[rq->tag] = rq; + return true; + } + + return __blk_mq_get_driver_tag(hctx, rq); +} static inline void blk_mq_clear_mq_map(struct blk_mq_queue_map *qmap) {
--
2.33.1