[rds-devel] [ofa-general] [PATCH RFC] rds: add iwarp support

[Olaf Kirch]

On Tuesday 08 July 2008 12:11:40 Or Gerlitz wrote:
> Olaf Kirch wrote:
> > Okay, there's a third way to fix this, which may even work with today's Oracle IPC code. The hack is to not submit the fastreg WR until we post a SEND that transmits the rkey to a peer. Then
> >
> >  -	we have a QP to post the WRs to
> >  -	we post the fastreg and the SEND to the same QP,
> > 	ensuring that the peer doesn't initiate the RDMA
> > 	before we've set up the memory registration.
> Yes, as Steve noted, using the same QP for the fastreg and send that 
> carries the rkey/stag is a must since the send should be fenced on the 
> fastreg completion to make sure the remote side uses a valid key.

One theoretical problem is what happens if the application wants to
register a memory range and send the rkey to two peers at the same time?
We would have to stall the second send explicitly as long as we
haven't seen the completion for the first send.

Olaf
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