RE: [RFC] XRC upstream merge reboot

Hefty, Sean
2011-08-02T23:53:06Z

> 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.

> 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.

- Sean