Re: [PATCH 00/12] introduce fail-safe PMD

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri,  3 Mar 2017 16:40:22 +0100
Gaetan Rivet <gaetan.rivet@6wind.com> wrote:

> This PMD intercepts and manages Ethernet device removal events issued by
> slave PMDs and re-initializes them transparently when brought back so that
> existing applications do not need to be modified to benefit from true
> hot-plugging support.
> 
> The stacked PMD approach shares many similarities with the bonding PMD but
> with a different purpose. While bonding provides the ability to group
> several links into a single logical device for enhanced throughput and
> supports fail-over at link level, this one manages the sudden disappearance
> of the underlying device; it guarantees applications face a valid device in
> working order at all times.
> 
> Each fail-safe instance is configured to run atop one or several
> devices, with one defined as the preferred device. Hot-plug events are
> handled on all of them, and Tx is always directed to the preferred device
> if present or to the next available failover device (Rx is always performed
> on all devices for simplicity).
> 
> Moreover, the configured slaves (preferred or failover) do not need to be
> present at initialization time and may appear later.
> 
> Slaves configuration is continuously synchronized with that of the virtual
> device, which exposes their common set of capabilities to the application.
> Failure to apply the current configuration state to a slave for any reason
> simply reschedules its initialization.
> 

This looks interesting for SR-IOV VF support on Hyper-V.
It would be good if the driver worked in interrupt mode as well.