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    SubjectRe: [PATCH v5 04/12] Provide special async page fault handler when async PF capability is detected
    On 08/23/2010 11:48 AM, Avi Kivity wrote:

    > Do you need to match cpu here as well? Or is token globally unique?
    >
    > Perhaps we should make it locally unique to remove a requirement from
    > the host to synchronize? I haven't seen how you generate it yet.

    If a task goes to sleep on one VCPU, but that VCPU ends
    up not being runnable later on, it would be nice to wake
    the task up on on a different VCPU.

    I do not remember why it is safe to send this wakeup
    event as an exception rather than an interrupt...

    > The other cpu might be waiting for us to yield. We can fix it later with
    > the the pv spinlock infrastructure.
    >
    > Or, we can avoid the allocation. If at most one apf can be pending (is
    > this true?), we can use a per-cpu variable for this dummy entry.

    Having a limit of just one APF pending kind of defeats
    the point.

    At that point, a second one of these faults would put
    the VCPU to sleep, which prevents the first task from
    running once its pagefault (which started earlier)
    completes...

    --
    All rights reversed


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