'Classify pid into cgroup
:param pid: pid of the process
:param cgroup: cgroup name'

def cgclassify_cgroup(self, pid, cgroup):

    try:
        cgroup_pwd = self.__get_cgroup_pwd(cgroup)
        if (cgroup_pwd not in self.cgroups):
            raise error.TestError(("%s    doesn't    exist!" % cgroup))
        cgclassify_cmd = ('cgclassify    -g    %s:%s    %d' % (self.module, cgroup, pid))
        utils.run(cgclassify_cmd, ignore_status=False)
    except error.CmdError as detail:
        raise error.TestFail(('Classify    process    to    tasks    file    failed!:%s' % detail))
