[libvirt] 'dommemstat' is not working for LXC hypervisor.

Ryota Ozaki ozaki.ryota at gmail.com
Thu Apr 29 13:23:38 UTC 2010


On Thu, Apr 29, 2010 at 9:54 PM, Kumar L Srikanth-B22348
<B22348 at freescale.com> wrote:
> Thanks Ozaki.
> Please let me know the result, once you checked with 0.8.0.

I may understand what happen.

Could you check 'tree -d /cgroup' where running your domain
and could you find that a directory named your domain
has another directory named some numeric number?

If so, could you try cgroup without ns subsystem like
mount -t cgroup -o cpu,cpuacct,cpuset,memory,devices cgroup /cgroup
or something.

I guess running lxc with ns subsystem of cgroup has still problems.

  ozaki-r


>
> Regards,
> Srikanth.
>
> -----Original Message-----
> From: Ryota Ozaki [mailto:ozaki.ryota at gmail.com]
> Sent: Thursday, April 29, 2010 6:14 PM
> To: Kumar L Srikanth-B22348
> Cc: Daniel P. Berrange; libvirt list; Ryota OZAKI
> Subject: Re: [libvirt] 'dommemstat' is not working for LXC hypervisor.
>
> On Thu, Apr 29, 2010 at 9:32 PM, Kumar L Srikanth-B22348 <B22348 at freescale.com> wrote:
>> Now it's showing Used Memory as 0. I don't know whether it's correct or not.
>> I wrote a small script in the domain to check the used memory, which will run continuously in the infinite loop.
>> dominfo 'domainname' is showing Used Memory as 0.
>> Is this right way to check the Used Memory of that domain?
>
> dominfo should be...but something wrong.
>
> In my machine, dominfo shows like:
>
> # virsh -c lxc:/// dominfo 31105
> Id:             31105
> Name:           cl_lxc_test
> UUID:           fd7b21d9-6cbb-17a8-53dd-233f0aed4b4a
> OS Type:        exe
> State:          running
> CPU(s):         1
> CPU time:       3.0s
> Max memory:     131072 kB
> Used memory:    23672 kB
> Autostart:      disable
>
> However, the version of libvirt is not 0.8.0. So I try to check what changed by recent updates.
>
> Thanks,
>  ozaki-r
>
>
>>
>> Regards,
>> Srikanth.
>>
>> -----Original Message-----
>> From: Ryota Ozaki [mailto:ozaki.ryota at gmail.com]
>> Sent: Thursday, April 29, 2010 5:50 PM
>> To: Kumar L Srikanth-B22348
>> Cc: Daniel P. Berrange; libvirt list; Ryota OZAKI
>> Subject: Re: [libvirt] 'dommemstat' is not working for LXC hypervisor.
>>
>> On Thu, Apr 29, 2010 at 9:14 PM, Kumar L Srikanth-B22348 <B22348 at freescale.com> wrote:
>>> Thanks ozaki.
>>> But can you please elaborate the process of getting memory.stat of a particular domain?
>>> I mounted cgroup filesystem prior to start libvirtd service using the below command:
>>> mount -t cgroup cgroup /cgroup
>>>
>>> Then started libvirtd service.
>>> Then started the domain.
>>>
>>> Here, can you let me know the process of viewing memory stats of that particular domain?
>>
>> Could you check output of dominfo again. Cannot you get proper 'Used memory'?
>>
>>> By the way, in the /cgroup directory lot of files are created. In those, which one can be memory stats?
>>
>> /cgroup/memory.stat is.
>>
>>  ozaki-r
>>
>>>
>>> Regards,
>>> Srikanth.
>>>
>>> -----Original Message-----
>>> From: Ryota Ozaki [mailto:ozaki.ryota at gmail.com]
>>> Sent: Thursday, April 29, 2010 5:27 PM
>>> To: Kumar L Srikanth-B22348
>>> Cc: Daniel P. Berrange; libvirt list; Ryota OZAKI
>>> Subject: Re: [libvirt] 'dommemstat' is not working for LXC hypervisor.
>>>
>>> On Wed, Apr 28, 2010 at 8:19 PM, Kumar L Srikanth-B22348 <B22348 at freescale.com> wrote:
>>>> Daniel,
>>>> My requirement is to get how much memory is free in the guest domain.
>>>> Can you please let me know, how can I do that?
>>>
>>> Do you enable cgroup memory subsystem? If so, something wrong in lxc driver of 0.8.0.
>>>
>>> BTW, 'Used memory' includes both RSS and caches, so if you need total-RSS value, you should use dommemstat.
>>>
>>>> And also, as you said it's quite easy to implement dommemstats for
>>>> lxc driver, is there any possibility to implement that?
>>>
>>> We can get statistics of dommemstat easily through memory.stat of cgroup.memory subsystem except statistics of page faults.
>>>
>>>  ozaki-r
>>>
>>>>
>>>> Regards,
>>>> Srikanth.
>>>>
>>>> -----Original Message-----
>>>> From: Daniel P. Berrange [mailto:berrange at redhat.com]
>>>> Sent: Wednesday, April 28, 2010 4:46 PM
>>>> To: Kumar L Srikanth-B22348
>>>> Cc: libvir-list at redhat.com
>>>> Subject: Re: 'dommemstat' is not working for LXC hypervisor.
>>>>
>>>> On Wed, Apr 28, 2010 at 04:43:41PM +0530, Kumar L Srikanth-B22348 wrote:
>>>>> Thanks for the reply Daniel.
>>>>> Virsh dominfo dommand showing following results:
>>>>>
>>>>> Id:             32473
>>>>> Name:           vm1
>>>>> UUID:           f13bc513-15f2-1dd1-74f6-18c47931ece9
>>>>> OS Type:        exe
>>>>> State:          running
>>>>> CPU(s):         1
>>>>> Max memory:     5000000 kB
>>>>> Used memory:    5000000 kB
>>>>> Autostart:      disable
>>>>>
>>>>>
>>>>> Though whatever services running on the domain, every time used
>>>>> memory
>>>>
>>>>> is showing as 5000000 kB. Is that result is correct?
>>>>
>>>> The 'Max memory' 5000000 KB is the hard limit that is allocated to
>>>> the container. I thought that the 'used memory' field would be
>>>> lower, but its possible we don't have the actual stats for used
>>>> memory so just set both the same. I'd have to research the code again to answer for sure...
>>>>
>>>> Daniel
>>>> --
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>>>> |7D3B
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>>>>
>>>>
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>>>
>>>
>>
>>
>
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