[PATCH v8 8/8] nvme-multipath: queue-depth support for marginal paths

[John Meneghini]

Hannes, this patch fixes the queue-depth scheduler.  Please take a look.

On 7/9/25 5:26 PM, Bryan Gurney wrote:
> From: John Meneghini <jmeneghi at redhat.com>
> 
> Exclude marginal paths from queue-depth io policy. In the case where all
> paths are marginal and no optimized or non-optimized path is found, we
> fall back to __nvme_find_path which selects the best marginal path.
> 
> Tested-by: Bryan Gurney <bgurney at redhat.com>
> Signed-off-by: John Meneghini <jmeneghi at redhat.com>
> ---
>   drivers/nvme/host/multipath.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 8d4e54bb4261..767583e8454b 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -420,6 +420,9 @@ static struct nvme_ns *nvme_queue_depth_path(struct nvme_ns_head *head)
>   		if (nvme_path_is_disabled(ns))
>   			continue;
>   
> +		if (nvme_ctrl_is_marginal(ns->ctrl))
> +			continue;
> +
>   		depth = atomic_read(&ns->ctrl->nr_active);
>   
>   		switch (ns->ana_state) {
> @@ -443,7 +446,9 @@ static struct nvme_ns *nvme_queue_depth_path(struct nvme_ns_head *head)
>   			return best_opt;
>   	}
>   
> -	return best_opt ? best_opt : best_nonopt;
> +	best_opt = (best_opt) ? best_opt : best_nonopt;
> +
> +	return best_opt ? best_opt : __nvme_find_path(head, numa_node_id());
>   }
>   
>   static inline bool nvme_path_is_optimized(struct nvme_ns *ns)