blk-mq: immediately dispatch big size request

This is corresponding part for blk-mq. Disk with multiple hardware
queues doesn't need this as we only hold 1 request at most.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Shaohua Li 2016-11-03 17:03:54 -07:00 committed by Jens Axboe
parent 50d24c3440
commit 600271d900

View file

@ -1453,13 +1453,18 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
*/
plug = current->plug;
if (plug) {
struct request *last = NULL;
blk_mq_bio_to_request(rq, bio);
if (!request_count)
trace_block_plug(q);
else
last = list_entry_rq(plug->mq_list.prev);
blk_mq_put_ctx(data.ctx);
if (request_count >= BLK_MAX_REQUEST_COUNT) {
if (request_count >= BLK_MAX_REQUEST_COUNT || (last &&
blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
blk_flush_plug_list(plug, false);
trace_block_plug(q);
}