VMForVnodeCache
((VMForVnodeCache*)fCache)->fVnode = vnode;
return sizeof(VMForVnodeCache) + fCache->Commitment();
VMForVnodeCache* cache = new(gVnodeCacheObjectCache, 0) VMForVnodeCache;
static_assert(sizeof(VMForVnodeCache) <= sizeof(VMVnodeCache), "cache too large");