cgroup使用笔记 Hello

1. cat /proc/<pid>/cgroup 看到的数字0 1 2 3 4 5 来自于每个 group 的 hierarchy_id：

# cat /proc/19809/cgroup
5:freezer:/
4:memory:/apps
3:cpuset:/top-app
2:cpu:/top-app
1:blkio:/
0::/uid_10270/pid_19809

cat /proc/<pid>/cgroup
    proc_cgroup_show //proc/fs/base.c struct pid_entry tgid_base_stuff[]
        list_for_each_entry((root), &cgroup_roots, root_list) {
            seq_printf(m, "%d:", root->hierarchy_id);    
        }