Re: [RFD] cgroup: about multiple hierarchies

[Glauber Costa <glommer@parallels.com>]

On 02/22/2012 05:30 PM, Peter Zijlstra wrote:
> On Tue, 2012-02-21 at 13:19 -0800, Tejun Heo wrote:
>> So, I mean, I don't know.  What do other people think?  Is this a
>> unnecessary worry?  Are people generally happy with the way things
>> are?  Lennart, Kay, what do you guys think?
>
> FWIW I'm all for ripping the orthogonal hierarchy crap out, I hate it
> just about as much as you do judging from your write-up.
>
> Yes it will make some people unhappy, but I can live with that since my
> life will be easier.. :-)
>
> I'm not sure on your process hierarchy pie though, I rather like being
> able to assign tasks to cgroups of my making without having to mirror
> that in the process hierarchy.
>
> Having seen what userspace does (libvirt in particular, I've still
> managed to not get infected by the systemd crap) its utterly and
> completely insane. Now I don't think any of my machines actually still
> have libvirt on it, so I don't care if we break that either ;-)
>
> Another thing I dislike about all the cgroup crap is all the dozens of
> tiny controllers being proposed left right and center. Like WTF isn't
> the hugetlb controller part of memcg? Its all memory, right?
>
Right. But this is easy to solve.
People are usually pointing out that "Hey, but that's not how my 
controller works, I need it to be slightly different here and there".
If we agree this is a bad thing - I think it is, we can at least adopt 
as a policy not to take any patches that create another hierarchy unless 
the need is utterly demonstrated.