how to get each process handler in given cgroup system

[Ian jonhson]

Hi all,

In my development, I need to traverse all the processes in given
cgroup subsystem, collecting some information in their PCB.
But I don't know how to loop around all the processes and
then get corresponding process handlers.

I have browsed two cgroup subsystems (CPU, Memory) which
have been embedded in mainstream, however I can not get
useful hints.

Could any body give me some advices?

Thanks in advance,

Ian