On Wed, Jul 05, 2017 at 08:00:34PM +0300, Sagi Grimberg wrote:
> When we requeue a request, we can always insert the request
> back to the scheduler instead of doing it when restarting
> the queues and kicking the requeue work, so get rid of
> the requeue kick in nvme (core and drivers).
>
> Also, now there is no need start hw queues in nvme_kill_queues
> We don't stop the hw queues anymore, so no need to
> start them.
>
> Signed-off-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
> ---
> drivers/nvme/host/core.c | 19 ++-----------------
> 1 file changed, 2 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index d70df1d0072d..48cafaa6fbc5 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -131,7 +131,7 @@ void nvme_complete_rq(struct request *req)
> {
> if (unlikely(nvme_req(req)->status && nvme_req_needs_retry(req))) {
> nvme_req(req)->retries++;
> - blk_mq_requeue_request(req, !blk_mq_queue_stopped(req->q));
> + blk_mq_requeue_request(req, true);
> return;
> }
>
> @@ -2694,9 +2694,6 @@ void nvme_kill_queues(struct nvme_ctrl *ctrl)
> /* Forcibly unquiesce queues to avoid blocking dispatch */
> blk_mq_unquiesce_queue(ctrl->admin_q);
>
> - /* Forcibly start all queues to avoid having stuck requests */
> - blk_mq_start_hw_queues(ctrl->admin_q);
> -
> list_for_each_entry(ns, &ctrl->namespaces, list) {
> /*
> * Revalidating a dead namespace sets capacity to 0. This will
> @@ -2709,16 +2706,6 @@ void nvme_kill_queues(struct nvme_ctrl *ctrl)
>
> /* Forcibly unquiesce queues to avoid blocking dispatch */
> blk_mq_unquiesce_queue(ns->queue);
> -
> - /*
> - * Forcibly start all queues to avoid having stuck requests.
> - * Note that we must ensure the queues are not stopped
> - * when the final removal happens.
> - */
> - blk_mq_start_hw_queues(ns->queue);
> -
> - /* draining requests in requeue list */
> - blk_mq_kick_requeue_list(ns->queue);
> }
> mutex_unlock(&ctrl->namespaces_mutex);
> }
> @@ -2787,10 +2774,8 @@ void nvme_start_queues(struct nvme_ctrl *ctrl)
> struct nvme_ns *ns;
>
> mutex_lock(&ctrl->namespaces_mutex);
> - list_for_each_entry(ns, &ctrl->namespaces, list) {
> + list_for_each_entry(ns, &ctrl->namespaces, list)
> blk_mq_unquiesce_queue(ns->queue);
> - blk_mq_kick_requeue_list(ns->queue);
> - }
> mutex_unlock(&ctrl->namespaces_mutex);
> }
> EXPORT_SYMBOL_GPL(nvme_start_queues);
> --
> 2.7.4
>
Yeah, this is a good cleanup, and be one of my motivation of
the quiesce improvement, and I believe we can do more this kind of
cleanup to remove racy stop/start queue in other drivers.
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
--
Ming
