Re: [PATCH 13/13] docs: nvme-multipath: Add FC-NVMe marginal state

[Randy Dunlap]

On 8/12/26 11:13 AM, Jesse Taube wrote:
> Adds documentation for the new marginal state for
> NVMe over Fibre Channel. Documents how to check and reset the state,
> as well as a description of how it affects multipath policies.
> 
> Signed-off-by: Jesse Taube <jtaubepe@xxxxxxxxxx>
> ---
>  Documentation/admin-guide/nvme-multipath.rst | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 

'make htmldocs' build warnings:

linux-next/Documentation/admin-guide/nvme-multipath.rst:35: WARNING: Title underline too short.

FC-NVMe
---- [docutils]
linux-next/Documentation/admin-guide/nvme-multipath.rst:50: ERROR: Unexpected indentation. [docutils]

> diff --git a/Documentation/admin-guide/nvme-multipath.rst b/Documentation/admin-guide/nvme-multipath.rst
> index 97ca1ccef459..8df4235d4d10 100644
> --- a/Documentation/admin-guide/nvme-multipath.rst
> +++ b/Documentation/admin-guide/nvme-multipath.rst
> @@ -31,6 +31,23 @@ To set the desired policy (e.g., round-robin), use one of the following methods:
>     1. echo -n "round-robin" > /sys/module/nvme_core/parameters/iopolicy
>     2. or add the "nvme_core.iopolicy=round-robin" to cmdline.
>  
> +FC-NVMe
> +----
> +On NVMe over Fibre Channel there is an additional state called `marginal`
> +All policies will treat this path as offline and will not use it unless
> +all other paths are marginal or unavailable. In that case, the policy will
> +select the best path based on the policy.
> +
> +To see the current path state, use one of the following methods:
> +   1. cat /sys/class/fc_host/host*/device/rport-*/fc_remote_ports/rport-*/port_state
> +   2. cat /sys/devices/virtual/nvme-subsystem/nvme-subsys*/nvme*/state
> +To reset a path to online use:
> +   1. echo "Online" > /sys/class/fc_host/host*/device/rport-*/fc_remote_ports/rport-*/port_state
> +
> +The marginal state is caused by a
> +FPIN-LI (Fabric Performance Impact Notification - Link Impact) event.
> +FPIN-LI event counters can be seen with:
> +   1. cat /sys/class/fc_host/host*/statistics/fpin_li*
>  
>  NUMA
>  ----

-- 
~Randy