Function needs_ensure 

pub fn needs_ensure(
    recorded_inode: Option<u64>,
    current_inode: Option<u64>,
) -> bool

Whether a rule cgroup’s limits must be (re)written. recorded_inode is the cgroup directory’s inode when the limits were last written, current_inode its inode now (None: the cgroup does not exist). Limits are rewritten only when the cgroup is new or was recreated: writing memory.high below current usage makes the writer reclaim synchronously, so rewriting unchanged limits every tick costs the daemon real work under exactly the pressure it exists to handle.