Re: [RFC] Default child of a cgroup

Vivek Goyal
2008-01-31T21:13:49Z

On Thu, Jan 31, 2008 at 08:10:49AM +0530, Srivatsa Vaddagiri wrote:
> Hi,
> As we were implementing multiple-hierarchy support for CPU
> controller, we hit some oddities in its implementation, partly related
> to current cgroups implementation. Peter and I have been debating on the
> exact solution and I thought of bringing that discussion to lkml.
>
> Consider the cgroup filesystem structure for managing cpu resource.
>
> # mount -t cgroup -ocpu,cpuacct none /cgroup
> # mkdir /cgroup/A
> # mkdir /cgroup/B
> # mkdir /cgroup/A/a1
>
> will result in:
>
> /cgroup
> |------<tasks>
> |------<cpuacct.usage>
> |------<cpu.shares>
> |
> |----[A]
> | |----<tasks>
> | |----<cpuacct.usage>
> | |----<cpu.shares>
> | |
> | |---[a1]
> | |----<tasks>
> | |----<cpuacct.usage>
> | |----<cpu.shares>
> | |
> |
> |----[B]
> | |----<tasks>
> | |----<cpuacct.usage>
> | |----<cpu.shares>
> |
>
>
> Here are some questions that arise in this picture:
>
> 1. What is the relationship of the task-group in A/tasks with the
> task-group in A/a1/tasks? In otherwords do they form siblings
> of the same parent A?
>

Vatsa,

I don't know much about cgroups but got a query. How do we handle this if we
just go one level up? How do we define relationship between /cgroup/tasks and
/cgroup/A/tasks, or /cgroup/tasks and /cgroup/B/tasks?

To me lower levels should be handeled in the same way.

Thanks
Vivek