[libvirt] [RFC PATCH 1/2] rpc: Bump maximum message size to 32M

[Peter Krempa]

On Tue, May 23, 2017 at 09:38:01 +0200, Martin Kletzander wrote:
> On Mon, May 22, 2017 at 06:00:12PM +0200, Peter Krempa wrote:
> > While most of the APIs are okay with 16M messages, the bulk stats API
> > can run into the limit in big configurations. Before we devise a new
> > plan for this, bump this limit slightly to accomodate some more configs.
> > ---
> > src/rpc/virnetprotocol.x | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/src/rpc/virnetprotocol.x b/src/rpc/virnetprotocol.x
> > index ee9899059..901c67159 100644
> > --- a/src/rpc/virnetprotocol.x
> > +++ b/src/rpc/virnetprotocol.x
> > @@ -40,13 +40,13 @@ const VIR_NET_MESSAGE_INITIAL = 65536;
> > const VIR_NET_MESSAGE_LEGACY_PAYLOAD_MAX = 262120;
> > 
> > /* Maximum total message size (serialised). */
> > -const VIR_NET_MESSAGE_MAX = 16777216;
> > +const VIR_NET_MESSAGE_MAX = 33554432;
> > 
> 
> ACK.
> 
> Although if you changed it to something nicer to read so that it doesn't
> take someone too long to figure out it's actually just 32 MiB, that
> would be even better.  Whatever suits you, be it (1 << 25) or (32 * 2 <<
> 20) or (32 * 1024 * 1024) or anything else.  I know other numbers could
> be changed as well, but this one is most updated, currently.


I thought about that, but rpcgen is not clever enough:

  GEN      rpc/virnetprotocol.h
const VIR_NET_MESSAGE_MAX = 32 * 1024 * 1024;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
rpc/virnetprotocol.x, line 43: expected ';'
cannot shutdown /usr/bin/rpcgen:  at ./rpc/genprotocol.pl line 139.


> > /* Size of struct virNetMessageHeader (serialised)*/
> > const VIR_NET_MESSAGE_HEADER_MAX = 24;
> > 
> > /* Size of message payload */
> > -const VIR_NET_MESSAGE_PAYLOAD_MAX = 16777192;
> > +const VIR_NET_MESSAGE_PAYLOAD_MAX = 33554408;
> > 
> 
> and this could be:
> 
> const VIR_NET_MESSAGE_PAYLOAD_MAX = VIR_NET_MESSAGE_MAX - VIR_NET_MESSAGE_HEADER_MAX;

And this does not work in the same manner.

> 
> or is none of that supported by the parser?  In that case, just leave it
> like that.

Welp ...
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20170524/d57a9802/attachment-0001.sig>