cgroups/utils.go
func FindCgroupMountpoint(subsystem string) (string, error) {
	f, err := os.Open("/proc/self/mountinfo")
	if err != nil {
		return "", err
	}
	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		txt := scanner.Text()
		fields := strings.Split(txt, " ")
		for _, opt := range strings.Split(fields[len(fields)-1], ",") {
			if opt == subsystem {
				return fields[4], nil
			}
		}
	}
	if err := scanner.Err(); err != nil {
		return "", err
	}

	return "", NewNotFoundError(subsystem)
}
func FindCgroupMountpoint(subsystem string) (string, error) {
	f, err := os.Open("/proc/self/mountinfo")
	if err != nil {
		return "", err
	}
	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		txt := scanner.Text()
		fields := strings.Split(txt, " ")
		for _, opt := range strings.Split(fields[len(fields)-1], ",") {
			if opt == subsystem {
				return fields[4], nil
			}
		}
	}
	if err := scanner.Err(); err != nil {
		return "", err
	}

	return "", NewNotFoundError(subsystem)
}
// https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt