On Tue, 22 Aug 2017 13:31:27 +0200
David Hildenbrand [off-list ref] wrote:

On 21.08.2017 22:35, Radim Kr?m?? wrote:

quoted

We can add a variable instead of scanning all online VCPUs to know how
many are started.  We can't trivially tell which VCPU is the last one,
though.  

You could keep the started vcpus in a list. Then you might drop unsigned
started_vcpus;

No started vcpus: Start pointer NULL
Single started vcpu: Only one element in the list (easy to check)

quoted

1 started vcpus: More than one element int he list (easy to check)  

I'm not sure the added complication of keeping a list buys us much
here: We only have the "look for the last vcpu not stopped" operation
for the 2->1 transition.