From 5f0ed774ed2914decfd397569fface997532e94d Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 23 Nov 2018 22:04:33 -0700 Subject: block: sum requests in the plug structure This isn't exactly the same as the previous count, as it includes requests for all devices. But that really doesn't matter, if we have more than the threshold (16) queued up, flush it. It's not worth it to have an expensive list loop for this. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/blk-mq.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) (limited to 'block/blk-mq.c') diff --git a/block/blk-mq.c b/block/blk-mq.c index cda698804422..7b7dff85cf6c 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1675,6 +1675,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) unsigned int depth; list_splice_init(&plug->mq_list, &list); + plug->rq_count = 0; list_sort(NULL, &list, plug_rq_cmp); @@ -1871,7 +1872,6 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) const int is_flush_fua = op_is_flush(bio->bi_opf); struct blk_mq_alloc_data data = { .flags = 0, .cmd_flags = bio->bi_opf }; struct request *rq; - unsigned int request_count = 0; struct blk_plug *plug; struct request *same_queue_rq = NULL; blk_qc_t cookie; @@ -1884,7 +1884,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) return BLK_QC_T_NONE; if (!is_flush_fua && !blk_queue_nomerges(q) && - blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq)) + blk_attempt_plug_merge(q, bio, &same_queue_rq)) return BLK_QC_T_NONE; if (blk_mq_sched_bio_merge(q, bio)) @@ -1915,20 +1915,12 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) blk_insert_flush(rq); blk_mq_run_hw_queue(data.hctx, true); } else if (plug && q->nr_hw_queues == 1) { + unsigned int request_count = plug->rq_count; struct request *last = NULL; blk_mq_put_ctx(data.ctx); blk_mq_bio_to_request(rq, bio); - /* - * @request_count may become stale because of schedule - * out, so check the list again. - */ - if (list_empty(&plug->mq_list)) - request_count = 0; - else if (blk_queue_nomerges(q)) - request_count = blk_plug_queued_count(q); - if (!request_count) trace_block_plug(q); else @@ -1941,6 +1933,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) } list_add_tail(&rq->queuelist, &plug->mq_list); + plug->rq_count++; } else if (plug && !blk_queue_nomerges(q)) { blk_mq_bio_to_request(rq, bio); @@ -1956,6 +1949,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) if (same_queue_rq) list_del_init(&same_queue_rq->queuelist); list_add_tail(&rq->queuelist, &plug->mq_list); + plug->rq_count++; blk_mq_put_ctx(data.ctx); -- cgit v1.2.3