[openib-general] Re: user_mad: large rmpp length problem

[Sean Hefty]

Hal Rosenstock wrote:
>>This may work.  I think that there may be issues with respect to providing 
>>proper synchronization and handling retries, but without looking at an 
>>implementation, I can't be sure.
> 
> Possibly timeouts too. I would prefer to take this a step at a time. I
> think that allocating some number of page sized chunks is likely to work
> and IMO we should first go down this direction. If this proves
> problematic, we can then adjust the strategy.

Even if the copy to the kernel were deferred on the send side, the receive side 
will still fully reassemble the MAD before giving it to a client.  The receive 
MAD will consume multiple data buffers, rather than a single buffer.  But it 
will still result in consuming kernel memory, and more than that required on the 
send side because of duplicated headers.

- Sean