Fixes#344
Add host cgroup support for kata.
This commits only adds cpu.cfs_period and cpu.cfs_quota support.
It will create 3-level hierarchy, take "cpu" cgroup as an example:
```
/sys/fs/cgroup
|---cpu
|---kata
|---<sandbox-id>
|--vcpu
|---<sandbox-id>
```
* `vc` cgroup is common parent for all kata-container sandbox, it won't be removed
after sandbox removed. This cgroup has no limitation.
* `<sandbox-id>` cgroup is the layer for each sandbox, it contains all other qemu
threads except for vcpu threads. In future, we can consider putting all shim
processes and proxy process here. This cgroup has no limitation yet.
* `vcpu` cgroup contains vcpu threads from qemu. Currently cpu quota and period
constraint applies to this cgroup.
Signed-off-by: Wei Zhang <zhangwei555@huawei.com>
Signed-off-by: Jingxiao Lu <lujingxiao@huawei.com>
34fe3b9d6d