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SubjectRe: Use of barriers in pvclock ABI
Glauber Costa wrote:
> Okay for guest vcpu, but what about physical cpus?
>
> IIRC, the checks are there, and so strict, to account for the
> possiblity of the vcpu to be migrated to another cpu in the middle of
> the
> clock reading.
>

That's fine. As part of rescheduling a vcpu on a new pcpu, the clock
record will be updated with the new cpu's parameters, but that update
will be complete by the time the vcpu gets rescheduled. The version
check and loop still needs to be there, but it will never see an
inconsistent (partially updated) clock record.

J


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