creating cgroup hierarchy

[Simon Brandner]

Hello,

i tried to create sub-directories in a cgroups mount.

I tried the following:
# mkdir test
# cd test
# echo 0 > cpuset.mems
# echo 0 > cpuset.cpus
# cat memory.use_hierarchy
1
# mkdir subtest
mkdir: cannot create directory `subtest': Invalid argument

So it did not work. Several tutorials mention a hierarchy or subgroups would be possible, but in none it was descibed how to manage this.
Could this feature be disabled in the kernel or somewhere else?

My active Kernel version is:
26.34.7-61.fc13.i686

Regards,

Simon

[Simon Brandner]

Hello,
> # mkdir test
> # cd test
> # echo 0 > cpuset.mems
> # echo 0 > cpuset.cpus
> # cat memory.use_hierarchy
> 1
> # mkdir subtest
> mkdir: cannot create directory `subtest': Invalid argument
> Could this feature be disabled in the kernel or somewhere else?
> My active Kernel version is:
> 26.34.7-61.fc13.i686

A small update to my tests:
Environment was in VM VirtualBox.
Aonther Test with Ubuntu in VirtualBox with Kernel version:
2.6.32-25-generic
allowed me to execute the commands mentioned above to create hierarchical cgroups. Could this feature have been intentionally disabled in the more recent Kernel version or fedora?

Regards,

Simon

[Simon Brandner]

Hello again,
> # mkdir test
> # cd test
> # echo 0 > cpuset.mems
> # echo 0 > cpuset.cpus
> # cat memory.use_hierarchy
> 1
> # mkdir subtest
> mkdir: cannot create directory `subtest': Invalid argument
> Could this feature be disabled in the kernel or somewhere else?
> My active Kernel version is:
> 26.34.7-61.fc13.i686

Another update, which solved my cgroup problem:
it seems the blkio or maybe other options which are active if no mount-option is explicitely selected, do not support deeper hierarchies. (Thanks to Pro-Linux.de for this advice).

In Ubuntu everything worked fine, because the blocking module was not yet integrated into the kernel..

Mounting with options like cpu,memory,cpuset subdirectories work like a charm.

Regards,

Simon