On 04/28/2011 10:34 AM, Michal Privoznik wrote:
Users often edit XML domain file stored in configuration directory thinking of modifying a domain/network/pool/etc. Thus it is wise to let them know they are using the wrong way and give them hint.
+++ b/src/conf/domain_conf.c @@ -8543,6 +8543,7 @@ int virDomainSaveConfig(const char *configDir, VIR_DOMAIN_XML_WRITE_FLAGS))) goto cleanup;
+ virSavePrependWarning(&xml); if (virDomainSaveXML(configDir, def, xml))
Prepending can be expensive - in the middle of the operation, we have to have twice the space for xml malloc'd, and we are also spending time on a memcpy from old memory to new. Is there any way to instead change virDomainSaveXML and friends to take a flags argument, and pass 0 from most callers but VIR_XML_EMIT_WARNING from these particular callers; then if the flag is set, they call the common helper function: virEmitXMLWarning(int fd) which outputs the message directly into the target file prior to outputting xml? That would be less memory pressure and copying involved. -- Eric Blake eblake@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org