[libvirt] [PATCH v3 2/2] nwfilter: Rebuild filters only if new filter is different than current

Compare two filters' XML for equality and only rebuild/instantiate the new filter if the new and current filters are found to be different. This improves performance during an update of a filter with no obvious change or the reloading of filters during a 'kill -SIGHUP' --- src/conf/nwfilter_conf.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) Index: libvirt-iterator/src/conf/nwfilter_conf.c =================================================================== --- libvirt-iterator.orig/src/conf/nwfilter_conf.c +++ libvirt-iterator/src/conf/nwfilter_conf.c @@ -2809,6 +2809,35 @@ virNWFilterTestUnassignDef(virConnectPtr return rc; } +static bool +virNWFilterDefEqual(const virNWFilterDefPtr def1, virNWFilterDefPtr def2, + bool cmpUUIDs) +{ + bool ret = false; + unsigned char rem_uuid[VIR_UUID_BUFLEN]; + char *xml1, *xml2 = NULL; + + if (!cmpUUIDs) { + /* make sure the UUIDs are equal */ + memcpy(rem_uuid, def2->uuid, sizeof(rem_uuid)); + memcpy(def2->uuid, def1->uuid, sizeof(def2->uuid)); + } + + if (!(xml1 = virNWFilterDefFormat(def1)) || + !(xml2 = virNWFilterDefFormat(def2))) + goto cleanup; + + ret = STREQ(xml1, xml2); + + if (!cmpUUIDs) + memcpy(def2->uuid, rem_uuid, sizeof(rem_uuid)); + +cleanup: + VIR_FREE(xml1); + VIR_FREE(xml2); + + return ret; +} virNWFilterObjPtr virNWFilterObjAssignDef(virConnectPtr conn, @@ -2840,6 +2869,14 @@ virNWFilterObjAssignDef(virConnectPtr co virNWFilterLockFilterUpdates(); if ((nwfilter = virNWFilterObjFindByName(nwfilters, def->name))) { + + if (virNWFilterDefEqual(def, nwfilter->def, false)) { + virNWFilterDefFree(nwfilter->def); + nwfilter->def = def; + virNWFilterUnlockFilterUpdates(); + return nwfilter; + } + nwfilter->newDef = def; /* trigger the update on VMs referencing the filter */ if (virNWFilterTriggerVMFilterRebuild(conn)) {