[libvirt-users] Is this Race Condition?

[Richard W.M. Jones]

On Thu, Apr 05, 2012 at 06:06:43PM +0800, Zhihua Che wrote:
> Hi, everyone
> 
>     I'm  writing application using libvirt and I need call
> virDomainGetCPUStats to get domain cpu stats . I learn from API
> reference that this function has to be called when domain is running.
> So my question is if there is an atomic way to test the domain's state
> and get its stats?
> 
>    Or, it's ok to call this function when domain is not active, but
> caller just gets error returned.
> 
>    In my code, I just call it directly and return error. I wonder if
> this programming practice has subtle problem like race condition.

AFAIK there is no way to do this without a race, not least because a
VM can power itself off / crash at literally any time.  In virt-top,
we just catch the error and ignore it.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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