Re: RDMA device renames and node description

[Jason Gunthorpe <jgg@ziepe.ca>]

On Wed, Feb 19, 2020 at 09:14:06AM -0500, Dennis Dalessandro wrote:

> > ABI breakage is a strong word, luckily enough it is not defined at all.
> > We never considered dmesg prints, device names, device ordering as an
> > ABI. You can't rely on debug features too, they can disappear too.
> 
> Agree, it is a strong word and we can call it what you want. The point is
> you should be able to rely on the node description not being changed out
> from under you unnecessarily though. We aren't talking about a debug feature
> here but a core feature to real world deployments.

People really use the node description as some stable name? And then
they put the HCA name in it? Why?

Is that some thing unique to the OPA subnet manager?

I don't recall people complaining about this when we introduced
rdma-ndd by default and changed all the node descriptions away from
the kernel default.

Also don't forget the whole thing about the node description is
inherently racey, so relying on it is Rather A Bad Idea.

Should we change the default format string of rdma-ndd to something
else?

Jason