cgroup_attach_task
DEFINE_EVENT(cgroup_migrate, cgroup_attach_task,
int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
ret = cgroup_attach_task(cgrp, task, threadgroup);
retval = cgroup_attach_task(from_cgrp, tsk, false);
ret = cgroup_attach_task(dst_cgrp, task, threadgroup);