In the discussion : http://thread.gmane.org/gmane.comp.emulators.libvirt/53534 People mentioned about long-term operations' LOCKs there. It seems that, in libxl_driver, certain opeations may hold a lock for too long, thus other operations, even those just do query jobs, would be blocked. In qemu_driver, there seems to be a more complexy way to solve this problem, by employing a condition variable. My question is : Is "Fixing such problem in libxl_driver" in our todo-list? If yes, what's the detailed solution? Will that be similar to qemu's CONDITION VARIABLE method?