Re: [libvirt] [PATCHv4 1/4] vcpupin: inroduce a new libvir API (virDomainPinVcpuFlags)

On 05/20/2011 02:54 PM, Adam Litke wrote: > I am really confused about what the default flags > (VIR_DOMAIN_VCPU_CURRENT) actually means. It doesn't seem like I can > ever know what it means from an API perspective (since it's behavior is > arbitrary depending on the hypervisor). Wouldn't it be better to > require _either_ VIR_DOMAIN_VCPU_LIVE _or_ VIR_DOMAIN_VCPU_CONFIG to be > set so that the intended behavior can be set with specificity? Anywhere we use _CURRENT, it is supposed to mean _LIVE (if the VM is running) or _CONFIG (if the VM is persistent but offline). Yes, explicitly specifying _LIVE, _CONFIG, or the combination of both, is probably better. And in the past, we haven't always used those conventions; that is, there are some APIs where _CURRENT is non-zero, and the default (0) was unclear in its meaning. But all new APIs should use _CURRENT as 0, so that the default has clear semantics. However, there are some hypervisors that cannot do just _LIVE on persistent domains - they can only do _LIVE|_CONFIG (for transient domains, though, it should be obvious that just _LIVE works, since _CONFIG cannot succeed on a transient domain).