It covers the addition of four new parameters that may be set in a forthcoming version of the PBS Pro cgroups hook. This review is time sensitive, so I ask that you respond with comments at your earliest convenience.
In general it looks good to me, thanks @mkaro! It might be helpful to include in interface 1 how or if this impacts the resources_available.ncpus on the vnode.
Just a minor terminology nit: what is being discussed here is the interoperability between cgroups and systemd. v2 cgroups are not used by any major distribution right now, and are (AFAIK) only related because systemd is getting prepared to become the single writer for all cgroup-related operations. But the namespaces and controls present for cgroups are very much still v1 cgroups.