changing cpuset of jail from inside of jail - is it feature?

[Miroslav Lachman]

Bjoern A. Zeeb wrote:

[...]

> Ok, I am not sure what is going wrong here; well I know but I don't
> know if it's intended in cpuset.  Trying to talk to the right people
> but they seen to be AWOL atm.
> 
> 
> If you are brave, you could try:
> 
> http://people.freebsd.org/~bz/20090423-01-cpuset-jails.diff
> 
> I haven't even compiled it yet. It may work, it may not work, it may
> make your machine panicing, ... just to warn you.
> 
> it should still allow you to create further sets within a jail but you
> should not be able to change the "root set" of the jail from inside
> the jail anymore (in case it works;)

I did just a quick test. (OK, not so quick, because compilation inside 
Qemu on my old PC takes 2 hours ;])
It compiles without problems and did what I expect:

root at 72-rc1 ~/# jls
    JID  IP Address      Hostname                      Path
      1                  alpha.test                    /usr/jail/alpha

root at 72-rc1 ~/# jexec 1 tcsh

root at alpha //# cpuset -l 0 -j 1
cpuset: setaffinity: Operation not permitted

root at alpha //# cpuset -l 0 -r -j 1
cpuset: setaffinity: Operation not permitted

I have no real multicore machine to test it more deeply. (can't test it 
on production servers and spare machine is blocked by another task)

Will this fix be included in 7.2-RELEASE or is it too late to commit 
this fix?

Miroslav Lachman