[libvirt] [PATCH] rpc: message related sizes enlarged

[Daniel P. Berrange]

On Mon, Apr 22, 2013 at 04:22:26PM +0200, Viktor Mihajlovski wrote:
> From: Daniel Hansel <daniel.hansel at linux.vnet.ibm.com>
> 
> We have seen an issue on s390x platform where domain XMLs larger than 1MB
> were used. The define command was finished successfully. The dumpxml command
> was not successful (i.e. could not encode message payload).
> 
> Enlarged message related sizes (e.g. maximum string size, message size, etc.)
> to handle larger system configurations used on s390x platform.

I'm not against this in general, but before we enlarge this so much
there needs to be some code work to make RPC message encoding more
efficient. Currently virNetMessageEncodeHeader will allocate
VIR_NET_MESSAGE_MAX immediately, regardless of whether the message
being encoded acutally needs so much. The problem is that we can't
tell ahead of time how much space a message needs. We just can't go
on doing this if we're going to have such large max message size.
We need to start with small allocs & grow if we hit the size limit.

Daniel
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