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 <http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainInfo>, 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. *Regards,* *Aleem Akhtar * *Research Assistant | HPC-Lab | SEECS* National University of Sciences & Technology Sector H-12, Islamabad Email: aleem.akhtar@seecs.nust.edu.pk <aleem.akhtar@seecs.nust.edu.pk> Website: aleemakhtar.com