From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:57504 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751198AbdD1PQ7 (ORCPT ); Fri, 28 Apr 2017 11:16:59 -0400 From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org Cc: Christoph Hellwig , Omar Sandoval , Ming Lei Subject: [PATCH 3/4] blk-mq: use hw tag for scheduling if hw tag space is big enough Date: Fri, 28 Apr 2017 23:15:38 +0800 Message-Id: <20170428151539.25514-4-ming.lei@redhat.com> In-Reply-To: <20170428151539.25514-1-ming.lei@redhat.com> References: <20170428151539.25514-1-ming.lei@redhat.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org 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 --- block/blk-mq-sched.c | 8 ++++++++ block/blk-mq-sched.h | 15 +++++++++++++++ block/blk-mq.c | 18 +++++++++++++++++- 3 files changed, 40 insertions(+), 1 deletion(-) diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 45a675f07b8b..4681e27c127e 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -507,6 +507,7 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e) struct elevator_queue *eq; unsigned int i; int ret; + bool auto_hw_tag; if (!e) { q->elevator = NULL; @@ -519,7 +520,14 @@ 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); + 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..22a19c118044 100644 --- a/block/blk-mq-sched.h +++ b/block/blk-mq-sched.h @@ -129,4 +129,19 @@ static inline bool blk_mq_sched_needs_restart(struct blk_mq_hw_ctx *hctx) return test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state); } +/* + * If this queue has enough hardware tags and doesn't share tags with + * other queues, just use hw tag directly for scheduling. + */ +static inline 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 (blk_mq_get_queue_depth(q) < q->nr_requests) + return false; + + return true; +} + #endif diff --git a/block/blk-mq.c b/block/blk-mq.c index 04761fb76ab4..b0bd1fb4b0f8 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2649,6 +2649,19 @@ int blk_mq_get_queue_depth(struct request_queue *q) return tags->bitmap_tags.sb.depth; } +static void blk_mq_update_sched_flag(struct request_queue *q) +{ + struct blk_mq_hw_ctx *hctx; + int i; + + if (!blk_mq_sched_may_use_hw_tag(q)) + queue_for_each_hw_ctx(q, hctx, i) + hctx->flags &= ~BLK_MQ_F_SCHED_USE_HW_TAG; + else + queue_for_each_hw_ctx(q, hctx, i) + hctx->flags |= BLK_MQ_F_SCHED_USE_HW_TAG; +} + int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) { struct blk_mq_tag_set *set = q->tag_set; @@ -2681,9 +2694,12 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) break; } - if (!ret) + if (!ret) { q->nr_requests = nr; + blk_mq_update_sched_flag(q); + } + blk_mq_unfreeze_queue(q); blk_mq_start_stopped_hw_queues(q, true); -- 2.9.3