[openib-general] Reregister Memory Region Verb

[Caitlin Bestler]

Fab Tillier wrote:
>> From: Caitlin Bestler [mailto:caitlinb at broadcom.com]
>> Sent: Wednesday, January 25, 2006 9:22 AM
>> 
>>>> although we would prefer that it wouldn't block if possible
>>> 
>>> mmm. All the current memory registration verbs both user and kernel
>>> are blocking, is it an issue for you?
>>> 
>> 
>> If you need to do memory registrations in a context where blocking is
>> not an option then you really need FMR work requests as in RDMAC and
>> InfiniBand 1.2 verbs.
> 
> No.  The blocking semantics of memory registration APIs is a
> deliberate design choice and not a limitation of the
> hardware.  It is possible (though more
> complicated) to make the API asynchronous.  No existing IB
> stack to date has ever done so, however.
> 
> - Fab

If asynchronous memory registration (via work request) is
such a bad idea then why is it part of both the RDMAC iWARP
and InfiniBand 1.2 verb specifications?