On Tue, May 14, 2024 at 01:53:17PM -0400, John Meneghini wrote:
> @@ -130,6 +133,7 @@ void nvme_mpath_start_request(struct request *rq)
> if (!blk_queue_io_stat(disk->queue) || blk_rq_is_passthrough(rq))
> return;
>
> + atomic_inc(&ns->ctrl->nr_active);
Why skip passthrough and stats?
And I think you should squash the follow up patch that constrains the
atomics to the queue-depth path selector.
> +static struct nvme_ns *nvme_queue_depth_path(struct nvme_ns_head *head)
> +{
> + struct nvme_ns *best_opt = NULL, *best_nonopt = NULL, *ns;
> + unsigned int min_depth_opt = UINT_MAX, min_depth_nonopt = UINT_MAX;
> + unsigned int depth;
> +
> + list_for_each_entry_rcu(ns, &head->list, siblings) {
> + if (nvme_path_is_disabled(ns))
> + continue;
> +
> + depth = atomic_read(&ns->ctrl->nr_active);
> +
> + switch (ns->ana_state) {
> + case NVME_ANA_OPTIMIZED:
> + if (depth < min_depth_opt) {
> + min_depth_opt = depth;
> + best_opt = ns;
> + }
> + break;
> +
> + case NVME_ANA_NONOPTIMIZED:
> + if (depth < min_depth_nonopt) {
> + min_depth_nonopt = depth;
> + best_nonopt = ns;
> + }
> + break;
> + default:
> + break;
> + }
> + }
> +
I think you can do the atomic_inc here so you don't have to check the io
policy a 2nd time.
> + return best_opt ? best_opt : best_nonopt;
> +}
