This small but important change would support a cgroup to swap to a particular file as setup by a new control file. This change is to allow the limiting of cgroups to a given swap file without being able to thrash the entire system's swap file. With this set of three patches, individual cgroups can be limited in their swap capacity.
This limiting of cgroups and their swap capacities should be very useful given the growing number of Linux container deployments. More details on these pending kernel patches can be found via the kernel mailing list.