[Lxc-users] cgroup question

[Kevin Wilson]

Hello,
Thanks a lot for your answer.

I reproduced the problem:
this is what I run: (after boot, in  Ubuntu 12.10)

mount -t tmpfs    cgroup_root    /cgroup

mkdir /cgroup/test1
mount -t cgroup -o cpuset,devices mytest    /cgroup/test1

And I get:
mount: mytest already mounted or /cgroup/test1 busy

shouldn't it work ?

I tried it on Ubuntu.
I was surprised to see that some cgroup contolkers are  mounted
under /sys/fs/cgroup (though it seems to me that this should not cause
a problem). systemd is not running on Ubuntu, I don't have any idea
who
mounted in boot time the /sys/fs/cgroup contollers and for which purpose

mount | grep cgroup
gives:
cgroup on /sys/fs/cgroup type tmpfs (rw,relatime,mode=755)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,relatime,cpuset)
cgroup on /sys/fs/cgroup/cpu type cgroup (rw,relatime,cpu)
cgroup on /sys/fs/cgroup/cpuacct type cgroup (rw,relatime,cpuacct)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,relatime,memory)
cgroup_root on /cgroup type tmpfs (rw)

Best regards,
Kevin

On Wed, Apr 10, 2013 at 4:09 PM, Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
> Quoting Kevin Wilson (wkevils at gmail.com):
>> Hello, lxc-users gurus,
>>
>> cgroup question:
>> Is it permitted to run this cgroup sequence:
>>
>> mount -t tmpfs cgroup_root /cgroup1
>> mount -t tmpfs cgroup_root /cgroup2
>>
>> And then try to create and mount subsystems to /cgroup1 and /cgroup2?
>>
>> or is permitted  to mount cgroup_root only once ?
>
> cgroup_root is just an arbitrary name on a tmpfs mount.  It has nothing
> to do with the actual cgroup filesystems.  It's the later steps which
> matter
> (i.e. mkdir /cgroup1/freezer; mount -t cgroupfs -o freezer freezer /cgroup1/freezer),
> but you don't show them here.
>
>> I don't have any error with  mounting twice cgroup_root, but i get error later
>> when trying to mount cpuset (for example) on /cgroup2
>>
>> rgs,
>> Kevin
>>
>>
>> Or is the
>>
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