nvme_disk: Queue requests if there are already requests queued.

This way, we don't do I/O out-of-order within a qpair under
heavy load conditions.
This commit is contained in:
Augustin Cavalier
2020-04-20 23:53:12 -04:00
parent fdfb71a406
commit 21b312b61e
@@ -1037,10 +1037,11 @@ int nvme_qpair_submit_request(struct nvme_qpair *qpair,
pthread_mutex_lock(&qpair->lock);
tr = LIST_FIRST(&qpair->free_tr);
if (tr == NULL || !qpair->enabled) {
if (tr == NULL || !qpair->enabled || !STAILQ_EMPTY(&qpair->queued_req)) {
/*
* No tracker is available, or the qpair is disabled due
* to an in-progress controller-level reset.
* No tracker is available, the qpair is disabled due
* to an in-progress controller-level reset, or
* there are already queued requests.
*
* Put the request on the qpair's request queue to be
* processed when a tracker frees up via a command
@@ -1048,6 +1049,9 @@ int nvme_qpair_submit_request(struct nvme_qpair *qpair,
*/
STAILQ_INSERT_TAIL(&qpair->queued_req, req, stailq);
pthread_mutex_unlock(&qpair->lock);
if (tr)
nvme_qpair_submit_queued_requests(qpair);
return 0;
}