[ofa-general] [PATCH RFC v3 1/2] RDMA/Core: MEM_MGT_EXTENSIONS support

[Steve Wise]

Roland Dreier wrote:
>  > * Do we want it to be a must for a consumer to invalidate an fast-reg
>  > mr before reusing it? if yes, how?
> 
> The verbs specs go into exhaustive detail about the state diagram for
> validity of MRs.
> 
>  > * talking about remote invalidation, I understand that it requires
>  > support of both sides (and hence has to be negotiated), so the
>  > IB_DEVICE_SEND_W_INV device capability says that a device can
>  > send-with-invalidate, do we need a IB_DEVICE_RECV_W_INV cap as well?
> 
> I think we decided that all of these related features will be indicated
> by IB_DEVICE_MEM_MGT_EXTENSIONS to avoid an explosion of capability bits.
> 

BTW:  a single capability bit doesn't allow apps to decide at run time 
whether to use read-with-inv, which is iwarp-only.  Perhaps we need that 
as its own capbility bit?  Or perhaps we can load detailed support/no 
support into the query device logic?  What it some devices can only 
support part of the suite of MEM_MGT_EXTENSIONS?


>  > * what about ZBVA, is it orthogonal to these calls, no enhancement of
>  > the suggested API is needed even if zbva is used, or the other way, it
>  > would work also when zbva is not used?
> 
> ZBVA would require adding some flag to request ZBVA when registering.
> 
>  - R.