Loadable cgroup subsystems

Paul Menage menage at google.com
Mon Apr 7 22:43:43 PDT 2008


On Mon, Apr 7, 2008 at 10:39 PM, Nikanth Karthikesan <knikanth at suse.de> wrote:
>
>  Why not provide a interface to add subsystems at run-time instead?
>  Are there any reason for not letting a subsystem to be implemented as a
>  loadable module? IOW make cgroups usable by modules?
>

Having all the subsystems declared at compile time makes a lot of
things (number of subsystems, size of css_set, etc) statically known,
which makes the code clearer and more importantly eliminates a bunch
of locking/synchronization overhead.

It would be possible to make cgroups support dynamically-loaded
subsystems, and in fact, some of the earliest cgroups patches did
support this, for a predefined max number of subsystems. But it would
introduce more complexity and overhead.

I'd rather not add support for this without a strong case of a
subsystem that really needs to be dynamically loaded.

Paul


More information about the Containers mailing list