Mounting blkio cgroup hierarchy

Mounting blkio cgroup hierarchy

[Ben Gamari]

I've been trying to configure cgroups and have encountered some very
strange behavior. In particular, when I follow the instructions in
Documentation/cgroups/blkio-controller.txt I quickly reach an error,

$ cd /mnt
$ sudo mkdir -p cgroups/blkio
$ # Confirm it's not already mounted:
$ cat /proc/mounts
rootfs / rootfs rw 0 0
none /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
none /proc proc rw,nosuid,nodev,noexec,relatime 0 0
none /dev devtmpfs rw,relatime,size=1993264k,nr_inodes=498316,mode=755 0 0
none /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
fusectl /sys/fs/fuse/connections fusectl rw,relatime 0 0
/dev/disk/by-uuid/7d908a9f-fe46-4a82-bb2b-3fc108c96280 / ext4 rw,relatime,errors=remount-ro,barrier=1,data=ordered 0 0
none /sys/kernel/debug debugfs rw,relatime 0 0
none /sys/kernel/security securityfs rw,relatime 0 0
none /dev/shm tmpfs rw,nosuid,nodev,relatime 0 0
none /var/run tmpfs rw,nosuid,relatime,mode=755 0 0
none /var/lock tmpfs rw,nosuid,nodev,noexec,relatime 0 0
/dev/sda1 /boot ext4 rw,relatime,barrier=1,data=ordered 0 0
binfmt_misc /proc/sys/fs/binfmt_misc binfmt_misc rw,nosuid,nodev,noexec,relatime 0 0
gvfs-fuse-daemon /home/ben/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0
$ sudo mount -t cgroup -o blkio none /mnt/cgroups/blkio
mount: special device none does not exist

I've done quite a bit of Googling and yet it's very difficult to find
good information on configuring cgroups. I would use the libcg
toolset[1] but every attempt to configure it has ended in frustratingly
vague error messages.

Any ideas?

Cheers,

- Ben

Re: Mounting blkio cgroup hierarchy

[Kirill A. Shutemov]

On Fri, Nov 12, 2010 at 12:13:24PM -0500, Ben Gamari wrote:
> Any ideas?

cat /proc/cgroups ?


-- 
 Kirill A. Shutemov

Re: Mounting blkio cgroup hierarchy

[Dhaval Giani]

On Fri, Nov 12, 2010 at 6:13 PM, Ben Gamari <bgamari@gmail.com> wrote:
> I've been trying to configure cgroups and have encountered some very
> strange behavior. In particular, when I follow the instructions in
> Documentation/cgroups/blkio-controller.txt I quickly reach an error,
>
> $ cd /mnt
> $ sudo mkdir -p cgroups/blkio
> $ # Confirm it's not already mounted:
> $ cat /proc/mounts
> rootfs / rootfs rw 0 0
> none /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
> none /proc proc rw,nosuid,nodev,noexec,relatime 0 0
> none /dev devtmpfs rw,relatime,size=1993264k,nr_inodes=498316,mode=755 0 0
> none /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
> fusectl /sys/fs/fuse/connections fusectl rw,relatime 0 0
> /dev/disk/by-uuid/7d908a9f-fe46-4a82-bb2b-3fc108c96280 / ext4 rw,relatime,errors=remount-ro,barrier=1,data=ordered 0 0
> none /sys/kernel/debug debugfs rw,relatime 0 0
> none /sys/kernel/security securityfs rw,relatime 0 0
> none /dev/shm tmpfs rw,nosuid,nodev,relatime 0 0
> none /var/run tmpfs rw,nosuid,relatime,mode=755 0 0
> none /var/lock tmpfs rw,nosuid,nodev,noexec,relatime 0 0
> /dev/sda1 /boot ext4 rw,relatime,barrier=1,data=ordered 0 0
> binfmt_misc /proc/sys/fs/binfmt_misc binfmt_misc rw,nosuid,nodev,noexec,relatime 0 0
> gvfs-fuse-daemon /home/ben/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0
> $ sudo mount -t cgroup -o blkio none /mnt/cgroups/blkio
> mount: special device none does not exist
>
> I've done quite a bit of Googling and yet it's very difficult to find
> good information on configuring cgroups. I would use the libcg
> toolset[1] but every attempt to configure it has ended in frustratingly
> vague error messages.
>

If you give us a hint with what error messages you are getting, at the
very least we can work on fixing those up :-)

Dhaval

Re: Mounting blkio cgroup hierarchy

[Li Zefan]

Ben Gamari wrote:
> I've been trying to configure cgroups and have encountered some very
> strange behavior. In particular, when I follow the instructions in
> Documentation/cgroups/blkio-controller.txt I quickly reach an error,
> 
> $ cd /mnt
> $ sudo mkdir -p cgroups/blkio
> $ # Confirm it's not already mounted:
> $ cat /proc/mounts
> $ sudo mount -t cgroup -o blkio none /mnt/cgroups/blkio
...
> mount: special device none does not exist
> 
> I've done quite a bit of Googling and yet it's very difficult to find
> good information on configuring cgroups. I would use the libcg
> toolset[1] but every attempt to configure it has ended in frustratingly
> vague error messages.
> 
> Any ideas?
> 

I suspect you didn't have blkio enabled in your kernel config.

So see if blkio is listed in /proc/cgroups or/and if CONFIG_BLK_CGROUP
is enabled in your kernel config.

Re: Mounting blkio cgroup hierarchy

[Ben Gamari]

On Mon, 15 Nov 2010 08:49:40 +0800, Li Zefan <lizf@cn.fujitsu.com> wrote:
> Ben Gamari wrote:
> > I've been trying to configure cgroups and have encountered some very
> > strange behavior. In particular, when I follow the instructions in
> > Documentation/cgroups/blkio-controller.txt I quickly reach an error,
> > 
> > $ cd /mnt
> > $ sudo mkdir -p cgroups/blkio
> > $ # Confirm it's not already mounted:
> > $ cat /proc/mounts
> > $ sudo mount -t cgroup -o blkio none /mnt/cgroups/blkio
> ...
> > mount: special device none does not exist
> > 
> > I've done quite a bit of Googling and yet it's very difficult to find
> > good information on configuring cgroups. I would use the libcg
> > toolset[1] but every attempt to configure it has ended in frustratingly
> > vague error messages.
> > 
> > Any ideas?
> > 
> 
> I suspect you didn't have blkio enabled in your kernel config.
> 
Doh! I could have sworn I had enabled this. Sorry for the noise!

- Ben