libprocessgroup: support for cgroup v2 hierarchy
for a first implementation the cgroup v2 freezer controller will be used in a
way similar to cgroup v1, that is a single child group will hold all frozen
processes. Some adjustments are needed for the new structure.
- Add support for cgroup v2 syntax under procfs.
- Separate creation of a directory with ownership/mode changes to allow changes
after mounting the cgroup kernfs root.
- Allow the creation of sub-groups under a cgroup v2 hierarchy.
Bug: 154548692
Test: manually verified that a proper cgroup v2 hierarchy is created and
accessible
Change-Id: I9af59e8214acaead3f520a94c95e75394c0df948
4 files changed