'Computes and logs the difference in memory utilization
between the given old and new memory data.'

def _log_diff_memory_data(self, prefix, new_memory_data, old_memory_data):

    def _vmem_used(memory_data):
        return memory_data['machine_data'].used
    def _process_mem_percent(memory_data):
        return memory_data['process_data']['memory_percent']
    def _process_rss(memory_data):
        return memory_data['process_data']['memory_info'].rss
    def _process_vms(memory_data):
        return memory_data['process_data']['memory_info'].vms
    if (new_memory_data and old_memory_data):
        log.info(u'%s    Diff    Vmem    used:    %s,    Diff    percent    memory:    %s,    Diff    rss:    %s,    Diff    vms:    %s', prefix, (_vmem_used(new_memory_data) - _vmem_used(old_memory_data)), (_process_mem_percent(new_memory_data) - _process_mem_percent(old_memory_data)), (_process_rss(new_memory_data) - _process_rss(old_memory_data)), (_process_vms(new_memory_data) - _process_vms(old_memory_data)))
