On Tue, May 28, 2024 at 09:43:08AM GMT, Tejun Heo <tj@xxxxxxxxxx> wrote: > I agree that this can be a useful metric but am not sure /proc/cgroups is > the right place to put it. Its use of v1 controller names, listing of > controllers that don't exist in v2 and the unnecessary column are rather > ugly and unnecessary. At the same time, the info provided currently is incorrect or at least misleading (when only v2 hierarchy is mounted, it mixes the counts) -- that's what T.J.'s patch attempts to rectify in my understanding. > In v2, cgroup.controllers and cgroup.subtree_control govern which > controllers are available and enabled in the subtree. Yes, users could sum up cgroup.controllers contents for true v2 fingerprint. > I think it would make sense to introduce something in a similar > fashion. Can't think of a good name off the top of my head but add a > cgroup. file which lists the controllers in the subtree along with the > number of css's. BTW, there is the 'debug' subsys that has (almost) exactly that: 'debug.csses' -- it's in v1 fashion though so it won't show hierarchical sums. Michal
