[libvirt] How to get VM memory usage

[Eric Blake]

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> ForwardedMessage.eml
> 
> Subject:
> Re: Re: [libvirt] How to get VM memory usage
> From:
> "wangyufeng at cloudguarding.com" <wangyufeng at cloudguarding.com>
> Date:
> 04/26/2017 01:21 AM
> 
> To:
> "Daniel P. Berrange" <berrange at redhat.com>
> CC:
> libvir-list <libvir-list at redhat.com>
> 
> 
> Hi Daniel,
> 
> I found method MemoryStats in domain.go:
> func (d *Domain) MemoryStats(nrStats uint32, flags uint32) ([]DomainMemoryStat, error) {
> ptr := make([]C.virDomainMemoryStatStruct, nrStats)
> 
> result := C.virDomainMemoryStats(
> d.ptr, (C.virDomainMemoryStatPtr)(unsafe.Pointer(&ptr[0])),
> C.uint(nrStats), C.uint(flags))
> 
> if result == -1 {
> return []DomainMemoryStat{}, GetLastError()
> }
> 
> out := make([]DomainMemoryStat, result)
> for i := 0; i < int(result); i++ {
> out = append(out, DomainMemoryStat{
> Tag: int32(ptr[i].tag),
> Val: uint64(ptr[i].val),
> })
> }
> return out, nil
> }
> 
> Do you mean this method can get used memory info?
> While I invoke the method, which can only get values of tag 0 and tag 6:
> 
> And the balloon driver have been activated on the monitored vm:
> 
> Below is my code, could you tell me what's wrong with my code?
> 
> Thank you very much.
> 
> ----------------------------------------------------------------------------------------------------------
> On Fri, Apr 21, 2017 at 09:58:12AM +0800, wangyufeng at cloudguarding.com wrote:
>> Hi Daniel,
>>
>> In method 'GetInfo', we can only get memory and max memory. However I
>> need to get used memory for calculating memory usage. The virsh command
>> 'dommemstat' can obtain used memory, is there a method in libvirt-go to
>> obtain used memory?
>  
> That command uses the virDomainMemoryStats() API call
>  
>  
> Regards,
> Daniel
> -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange
> :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |:
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-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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