[openib-general] Re: CMA backlog

[Michael S. Tsirkin]

Quoting r. Sean Hefty <sean.hefty at intel.com>:
> >Currently, this is not something that can be implemented by ULP on top of
> >CMA, because returning error from REQ will result in reject rather than REQ
> >drop.
> 
> A generic ULP could handle this by making use of the private data, and retrying
> requests after a REJ with insufficient resources.
 
You are right in this, of course. What I meant is that dropping REQ
can not be implemented by ULPs without extending our CMA and CM.

As you point out, retrying on reject might make sense for some
ULPs, but happily these can already implement this without extending CMA
and CM. So we are set there.

I suggest adding an option of dropping REQ, emulating TCP behaviour.
This is IMO required for SDP, as I read the spec and from I know about other
SDP implementations.

ULPs will be able to select the best approach appropriate for them.

-- 
MST