static void cgroup_kill(struct cgroup *cgrp)
{
	struct cgroup_subsys_state *css;
	struct cgroup *dsct;

	lockdep_assert_held(&cgroup_mutex);

	cgroup_for_each_live_descendant_pre(dsct, css, cgrp)
		__cgroup_kill(dsct);
}
static void cgroup_kill(struct cgroup *cgrp)
{
	struct cgroup_subsys_state *css;
	struct cgroup *dsct;

	lockdep_assert_held(&cgroup_mutex);

	cgroup_for_each_live_descendant_pre(dsct, css, cgrp)
		__cgroup_kill(dsct);
}