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SubjectRe: [PATCH RFC 0/2] KVM: use RCU to allow dynamic kvm->vcpus array
On 17/08/2017 09:36, Cornelia Huck wrote:
>> What if we just sent a "vcpu move" request to all vcpus with the new
>> pointer after it moved? That way the vcpu thread itself would be
>> responsible for the migration to the new memory region. Only if all
>> vcpus successfully moved, keep rolling (and allow foreign get_vcpu again).
>> That way we should be basically lock-less and scale well. For additional
>> icing, feel free to increase the vcpu array x2 every time it grows to
>> not run into the slow path too often.
> I'd prefer the rcu approach: This is a mechanism already understood
> well, no need to come up with a new one that will likely have its own
> share of problems.

What Alex is proposing _is_ RCU, except with a homegrown
synchronize_rcu. Using kvm->srcu seems to be the best of both worlds.


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