[Suggestion] kernel: cgroup: mount failure in LTP cgroup_regression_test.sh

[Suggestion] kernel: cgroup: mount failure in LTP cgroup_regression_test.sh

[Chen Gang]

Hello Maintainers:

On Fedora16 with defconfig for next-20131107 kernel, use latest LTP
(Linux Test Project) version, test_5() in cgroup_regression_test.sh
will be fail. The related LTP output:

  <<<test_start>>>
  tag=cgroup stime=1383562810
  cmdline="       cgroup_regression_test.sh"
  contacts=""
  analysis=exit
  <<<test_output>>>
  cgroup_regression_test    1  TPASS  :  no kernel bug was found
  /opt/ltp/testcases/bin/cgroup_regression_test.sh: line 118: 13283 Terminated              ./fork_processes
  cgroup_regression_test    2  TPASS  :  notify_on_release is inherited
  cgroup_regression_test    3  TCONF  :  CONFIG_SCHED_DEBUG is not enabled
  cgroup_regression_test    4  TCONF  :  CONFIG_LOCKDEP is not enabled
  mount: xxx already mounted or cgroup/ busy
  cgroup_regression_test    5  TFAIL  :  mount freezer and cpuacct failed
  cgroup_regression_test    6  TCONF  :  CONFIG_CGROUP_NS
  /opt/ltp/testcases/bin/cgroup_regression_test.sh: line 360: 24428 Terminated              sleep 100 < cgroup/0
  /opt/ltp/testcases/bin/cgroup_regression_test.sh: line 381: 24447 Terminated              sleep 100 < cgroup/0
  cgroup_regression_test    7  TPASS  :  no kernel bug was found
  cgroup_regression_test    8  TPASS  :  no kernel bug was found
  cgroup_regression_test    9  TPASS  :  no kernel warning was found
  rmdir: failed to remove `cgroup/0': No such file or directory
  umount: /sys/fs/cgroup/systemd: device is busy.
          (In some cases useful info about processes that use
           the device is found by lsof(8) or fuser(1))
  cgroup_regression_test   10  TPASS  :  no kernel warning was found
  <<<execution_status>>>
  initiation_status="ok"
  duration=62 termination_type=exited termination_id=1 corefile=no
  cutime=3341 cstime=6353
  <<<test_end>>>

After simplify, the related operation, environments and output are:

  [root@gchenlinux tmp]# df -Th | grep cgroup
  tmpfs                             tmpfs    1001M     0 1001M   0% /sys/fs/cgroup
  [root@gchenlinux tmp]# lsof | grep cgroup | grep -v grep
  systemd       1          root    6r      DIR               0,18         0       5998 /sys/fs/cgroup/systemd/system
  [root@gchenlinux tmp]# cat /proc/cgroups 
  #subsys_name	hierarchy	num_cgroups	enabled
  cpuset	3	4	1
  cpu	4	35	1
  cpuacct	4	35	1
  freezer	5	4	1
  [root@gchenlinux tmp]# mkdir cgroup
  [root@gchenlinux tmp]# mount -t cgroup -o freezer,cpuacct xxx cgroup/
  mount: xxx already mounted or cgroup/ busy

Is it real issue of cgroup? If it is, I will/should continue analyzing.


Welcome any additional suggestions and completions.

Thanks.
--
Chen Gang

Re: [Suggestion] kernel: cgroup: mount failure in LTP cgroup_regression_test.sh

[Tejun Heo]

Hello,

Sorry about the delay.

On Fri, Nov 08, 2013 at 04:15:23PM +0800, Chen Gang wrote:
> After simplify, the related operation, environments and output are:
> 
>   [root@gchenlinux tmp]# df -Th | grep cgroup
>   tmpfs                             tmpfs    1001M     0 1001M   0% /sys/fs/cgroup
>   [root@gchenlinux tmp]# lsof | grep cgroup | grep -v grep
>   systemd       1          root    6r      DIR               0,18         0       5998 /sys/fs/cgroup/systemd/system
>   [root@gchenlinux tmp]# cat /proc/cgroups 
>   #subsys_name	hierarchy	num_cgroups	enabled
>   cpuset	3	4	1
>   cpu	4	35	1
>   cpuacct	4	35	1
>   freezer	5	4	1
>   [root@gchenlinux tmp]# mkdir cgroup
>   [root@gchenlinux tmp]# mount -t cgroup -o freezer,cpuacct xxx cgroup/
>   mount: xxx already mounted or cgroup/ busy
> 
> Is it real issue of cgroup? If it is, I will/should continue analyzing.

Hmmm... I'm a bit confused.  What is it testing?  "cat /proc/cgroup"
is showing that freezer is already mounted and the kernel seems to
have correctly refused to mount it in a different hierarchy.  What am
I missing here?

Thanks.

-- 
tejun

Re: [Suggestion] kernel: cgroup: mount failure in LTP cgroup_regression_test.sh

[Chen Gang]

On 11/21/2013 01:35 AM, Tejun Heo wrote:
> Hello,
> 
> Sorry about the delay.
> 

Oh, No problem, every members time resources are expensive, thank you
for your reply.


> On Fri, Nov 08, 2013 at 04:15:23PM +0800, Chen Gang wrote:
>> After simplify, the related operation, environments and output are:
>>
>>   [root@gchenlinux tmp]# df -Th | grep cgroup
>>   tmpfs                             tmpfs    1001M     0 1001M   0% /sys/fs/cgroup
>>   [root@gchenlinux tmp]# lsof | grep cgroup | grep -v grep
>>   systemd       1          root    6r      DIR               0,18         0       5998 /sys/fs/cgroup/systemd/system
>>   [root@gchenlinux tmp]# cat /proc/cgroups 
>>   #subsys_name	hierarchy	num_cgroups	enabled
>>   cpuset	3	4	1
>>   cpu	4	35	1
>>   cpuacct	4	35	1
>>   freezer	5	4	1
>>   [root@gchenlinux tmp]# mkdir cgroup
>>   [root@gchenlinux tmp]# mount -t cgroup -o freezer,cpuacct xxx cgroup/
>>   mount: xxx already mounted or cgroup/ busy
>>
>> Is it real issue of cgroup? If it is, I will/should continue analyzing.
> 
> Hmmm... I'm a bit confused.  What is it testing?  "cat /proc/cgroup"
> is showing that freezer is already mounted and the kernel seems to
> have correctly refused to mount it in a different hierarchy.  What am
> I missing here?
> 

Hmm... I am not quit familiar about it, either, but at least I can
contact related LTP members (I guess they can make sure about it).


Excuse me, I am changing/finding new job, so I should not use Asianux
Corporation mail again.  And it seems I can not be focus on upstream
kernel as much as before.  :-(

But at least, I will/should continue providing some contributions (more
or less) to Public Open Source as volunteers. And for upstream kernel,
I plan to make 1-3 patches per month (mainly for cross compiling).

 - if can not get companies support, I can not provide enough time
   resource on upstream kernel (I have to get pay check for family).

 - New company may mainly focus on open source tool chains (not only
   kernel), so I will/should also provide some contributions to them
   (e.g. KVM, GCC ...).


At last, sorry again for I have to give up 10 patches per month for
upstream kernel.


Thanks.
-- 
Chen Gang