Hi Austin,I wouldn't consider them entirely orthogonal, the sysctl value is the limiting factor for the maximal value that can be set in a given pids cgroup. Setting an unlimited value in the cgroup is functionally identical to setting it to be equal to /proc/sys/kernel/pid_max, and the root cgroup is functionally equivalent to /proc/sys/kernel/pid_max, because all tasks that aren't in another cgroup get put in the root.
Does pids limit make sense in the root cgroup?I would say it kind of does, although I would just expect it to track
/proc/sys/kernel/pid_max (either as a read-only value, or as an alternative
way to set it).
Personally, that seems unintuitive. /proc/sys/kernel/pid_max and the pids
cgroup controller are orthogonal features, why should they be able to affect
each other (or even be aware of each other)?