[libvirt-users] VMs fail to start with NUMA configuration

[Osier Yang]

On 2013年01月28日 11:47, Osier Yang wrote:
> On 2013年01月28日 11:44, Osier Yang wrote:
>> On 2013年01月26日 01:07, Doug Goldstein wrote:
>>> On Thu, Jan 24, 2013 at 12:58 AM, Osier Yang<jyang at redhat.com> wrote:
>>>> On 2013年01月24日 14:26, Doug Goldstein wrote:
>>>>>
>>>>> On Wed, Jan 23, 2013 at 11:02 PM, Osier Yang<jyang at redhat.com> wrote:
>>>>>>
>>>>>> On 2013年01月24日 12:11, Doug Goldstein wrote:
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Jan 23, 2013 at 3:45 PM, Doug Goldstein<cardoe at gentoo.org>
>>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> I am using libvirt 0.10.2.2 and qemu-kvm 1.2.2 (qemu-kvm 1.2.0 +
>>>>>>>> qemu
>>>>>>>> 1.2.2 applied on top plus a number of stability patches). Having
>>>>>>>> issue
>>>>>>>> where my VMs fail to start with the following message:
>>>>>>>>
>>>>>>>> kvm_init_vcpu failed: Cannot allocate memory
>>>>>>
>>>>>>
>>>>>>
>>>>>> Smell likes we have problem on setting the NUMA policy (perhaps
>>>>>> caused by the incorrect host NUMA topology), given that the system
>>>>>> still has enough memory. Or numad (if it's installed) is doing
>>>>>> something wrong.
>>>>>>
>>>>>> Can you see if there is something about the Nodeset used to set
>>>>>> the policy in debug log?
>>>>>>
>>>>>> E.g.
>>>>>>
>>>>>> % cat libvirtd.debug | grep Nodeset
>>>>>
>>>>>
>>>>> Well I don't see anything but its likely because I didn't do something
>>>>> correct. I had LIBVIRT_DEBUG=1 exported and ran libvirtd --verbose
>>>>> from the command line.
>>>>
>>>>
>>>> If the process is in background, it's expected you can't see anything
>>>>
>>>>
>>>> My /etc/libvirt/libvirtd.conf had:
>>>>>
>>>>> log_outputs="3:syslog:libvirtd 1:file:/tmp/libvirtd.log" But I didn't
>>>>> get any debug messages.
>>>>
>>>>
>>>> log_level=1 has to be set.
>>>>
>>>> Anyway, let's simply do this:
>>>>
>>>> % service libvirtd stop
>>>> % LIBVIRT_DEBUG=1 /usr/sbin/libvirtd 2>&1 | tee -a libvirtd.debug
>>>>
>>>
>>> That's what I was doing, minus the tee just to the console and nothing
>>> was coming out. Which is why I added the 1:file:/tmp/libvirtd.log,
>>> which also didn't get any debug messages. Turns out this instance must
>>> have been built with --disable-debug,
>>>
>>> All I've got in the log is:
>>>
>>> # grep -i 'numa' libvirtd.debug
>>> 2013-01-25 16:50:15.287+0000: 417: debug : virCommandRunAsync:2200 :
>>> About to run /usr/bin/numad -w 2:2048
>>> 2013-01-25 16:50:17.295+0000: 417: debug : qemuProcessStart:3614 :
>>> Nodeset returned from numad: 1
>>
>> This looks right.
>>
>>>
>>> Immediately below that is
>>>
>>> 2013-01-25 16:50:17.295+0000: 417: debug : qemuProcessStart:3622 :
>>> Setting up domain cgroup (if required)
>>> 2013-01-25 16:50:17.295+0000: 417: debug : virCgroupNew:619 : New
>>> group /libvirt/qemu/bb-2.6.35.9-i686
>>> 2013-01-25 16:50:17.295+0000: 417: debug : virCgroupDetect:273 :
>>> Detected mount/mapping 1:cpuacct at /sys/fs/cgroup/cpuacct in
>>> 2013-01-25 16:50:17.295+0000: 417: debug : virCgroupDetect:273 :
>>> Detected mount/mapping 2:cpuset at /sys/fs/cgroup/cpuset in
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupMakeGroup:537 :
>>> Make group /libvirt/qemu/bb-2.6.35.9-i686
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupMakeGroup:562 :
>>> Make controller /sys/fs/cgroup/cpuacct/libvirt/qemu/bb-2.6.35.9-i686/
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupMakeGroup:562 :
>>> Make controller /sys/fs/cgroup/cpuset/libvirt/qemu/bb-2.6.35.9-i686/
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupCpuSetInherit:469
>>> : Setting up inheritance /libvirt/qemu ->
>>> /libvirt/qemu/bb-2.6.35.9-i686
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupGetValueStr:361 :
>>> Get value /sys/fs/cgroup/cpuset/libvirt/qemu/cpuset.cpus
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virFileClose:72 : Closed
>>> fd 39
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupCpuSetInherit:482
>>> : Inherit cpuset.cpus = 0-63
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupSetValueStr:331 :
>>> Set value
>>> '/sys/fs/cgroup/cpuset/libvirt/qemu/bb-2.6.35.9-i686/cpuset.cpus'
>>> to '0-63'
>>
>> This looks not right, it should be 0-7 instead.
>>
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virFileClose:72 : Closed
>>> fd 39
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupGetValueStr:361 :
>>> Get value /sys/fs/cgroup/cpuset/libvirt/qemu/cpuset.mems
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virFileClose:72 : Closed
>>> fd 39
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupCpuSetInherit:482
>>> : Inherit cpuset.mems = 0-7
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupSetValueStr:331 :
>>> Set value
>>> '/sys/fs/cgroup/cpuset/libvirt/qemu/bb-2.6.35.9-i686/cpuset.mems'
>>> to '0-7'
>>
>> This is right.
>>
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virFileClose:72 : Closed
>>> fd 39
>>> 2013-01-25 16:50:17.296+0000: 417: warning : qemuSetupCgroup:388 :
>>> Could not autoset a RSS limit for domain bb-2.6.35.9-i686
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virCgroupSetValueStr:331 :
>>> Set value
>>> '/sys/fs/cgroup/cpuset/libvirt/qemu/bb-2.6.35.9-i686/cpuset.mems'
>>> to '1'
>>
>> And it's strange that the cpuset.mems is changed to '1' here.

Oh, actually this is right, cpuset.mems is about the memory nodes.

>>
>>> 2013-01-25 16:50:17.296+0000: 417: debug : virFileClose:72 : Closed
>>> fd 39
>>>
>>> Could the RSS issue be related? Some kernel related option not playing
>>> nice or enabled?
>
> Instead, I'm wondering if the problem is caused by the mismatch
> (from libvirt p.o.v) between cpuset.cpus and cpuset.mems, which
> thus cause the problem for kernel memory management?

So, the simple method to prove the guess is to use static placement
like:

<vcpu placement='static' cpuset='0-63'>2</vcpu>
<numatune>
   <memory placement='static' nodeset='1'/>
</numatune>

Osier