RE: [RFC] XRC upstream merge reboot

Shamis, Pavel
2011-08-03T13:47:04Z

>
> > BTW, did we have the same limitation/feature (only creating process is
> allowed
> > to modify) in original XRC driver ?
>
> I'm not certain about the implementation, but the OFED APIs would allow
> any process within the xrc domain to modify the qp.
>
> > Hmm, is it way to destroy the QP, when the original process does not exist
> > anymore ?
>
> The only way to destroy the tgt qp after the creating process exits is for the
> xrc domain to be destroyed. Jack and I have discussed the possibility of
> having the kernel destroy the qp on error or ib cm disconnect. I'm not sure
> how likely it would be for a tgt qp will enter the error state. If it's possible
> under a fairly normal use case, I'll start on a separate patch to handle that
> case.
>

Well, actually I was thinking about APM. If the "creator" exits, we do not have a way to
upload alternative path.

> > Some MPI implements network fall tolerance mechanisms over IB. It
> means that
> > if QP (or device) enters to error state it should be a way to destroy the
> > specific QP and open new one.
>
> Note that a tgt qp should consume minimal resources, so it may not be a big
> deal to just leave it around. A new qp can be connected regardless.
>

Agree.

Regards,
Pasha