I am trying to get stats of Domains running under XEN hypervisor. I used Libvirt function for this purpose. I am trying to understand output for Memory. Domain running is Fedora-22 with 1GB Ram. Here is my code

y = virDomainGetInfo(allDomain, &info);
if (y == -1)
    printf("Errorl\n");
else {
    printf("Max Memory: %lu\n", info.maxMem);
    printf("Memory: %lu", info.memory);
}

I get output as

Max Memory: 1048576
Memory: 1048576

Now, as per Libvirt API, info.memory should return the memory in KBytes used by the domain. My Question is, if info.memory returns memory used and my domain is using complete 100% of Max Memory or not? Also I tried to create Domain with memory varying from 128MB to 2GB with same effect. I also tried to run some applications in Domain but Memory usage return by given function does not change. Any help or guidance will be much appreciated.