diff options
| author | Jens Axboe <axboe@kernel.dk> | 2018-11-27 17:13:56 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-11-29 10:11:45 -0700 |
| commit | ce5b009cff1961137127edf91f44effd0eec8ffd (patch) | |
| tree | 065b5b09d76828805afa8692a284e694c8cb1203 /block | |
| parent | 4e6db0f21c99c25980c8d183f95cdb6ad64cebd2 (diff) | |
block: improve logic around when to sort a plug list
Only do it if we have requests for multiple queues in the same
plug.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-core.c | 1 | ||||
| -rw-r--r-- | block/blk-mq.c | 23 |
2 files changed, 19 insertions, 5 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index be9233400314..d107d016b92b 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1780,6 +1780,7 @@ void blk_start_plug(struct blk_plug *plug) INIT_LIST_HEAD(&plug->mq_list); INIT_LIST_HEAD(&plug->cb_list); plug->rq_count = 0; + plug->multiple_queues = false; /* * Store ordering should not be needed here, since a potential diff --git a/block/blk-mq.c b/block/blk-mq.c index 5f4b93f424b4..2a1a653a8054 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1677,7 +1677,8 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) list_splice_init(&plug->mq_list, &list); plug->rq_count = 0; - list_sort(NULL, &list, plug_rq_cmp); + if (plug->rq_count > 2 && plug->multiple_queues) + list_sort(NULL, &list, plug_rq_cmp); this_q = NULL; this_hctx = NULL; @@ -1866,6 +1867,20 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, } } +static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq) +{ + list_add_tail(&rq->queuelist, &plug->mq_list); + plug->rq_count++; + if (!plug->multiple_queues && !list_is_singular(&plug->mq_list)) { + struct request *tmp; + + tmp = list_first_entry(&plug->mq_list, struct request, + queuelist); + if (tmp->q != rq->q) + plug->multiple_queues = true; + } +} + static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) { const int is_sync = op_is_sync(bio->bi_opf); @@ -1932,8 +1947,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) trace_block_plug(q); } - list_add_tail(&rq->queuelist, &plug->mq_list); - plug->rq_count++; + blk_add_rq_to_plug(plug, rq); } else if (plug && !blk_queue_nomerges(q)) { blk_mq_bio_to_request(rq, bio); @@ -1950,8 +1964,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) list_del_init(&same_queue_rq->queuelist); plug->rq_count--; } - list_add_tail(&rq->queuelist, &plug->mq_list); - plug->rq_count++; + blk_add_rq_to_plug(plug, rq); blk_mq_put_ctx(data.ctx); |