[rds-devel] Re: send-with-invalidate

[Olaf Kirch]

On Thursday 10 January 2008 12:39, Or Gerlitz wrote:
> Note that you have re-invented here the "send-with-invalidate" from the 
> IB spec... which is fine, since at least from what I know, Mellanox does 
> not show any intension to implement it in FW/SW.

I wasn't aware of that. But if it's not implemented anyway, then it's fine :)

> Anyway, with this at hand, maybe you want to go further and eliminate 
> the need for the get_mr system call on the client side, that mark to rds 
> to register these bytes and send the rkey/addr in the extended header 
> attached to the app message and provide the header to the app on the 
> remote side or an id which will let rds get the rkey/addr from it tables 
> etc.

Yeah, I was thinking along the same line - ie have the application
pass the memory region in a control message along with some "normal"
message; the kernel allocates a MR and passes its key along in a RDS
extension header; finally the remote kernel translates the MR into an
opaque token, which the application receives as a control message
along with the message data itself.

However, some applications may want to create long-lived MRs, so
we probably shouldn't disable the GET_MR call completely.

Olaf
-- 
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