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    SubjectRe: [RFC PATCH] Fix abnormal rcu dynticks_nesting values related to async page fault
    On Tue, Nov 27, 2012 at 04:56:30PM +0100, Frederic Weisbecker wrote:
    > 2012/11/27 Gleb Natapov <gleb@redhat.com>:
    > > For KVM_PV_REASON_PAGE_NOT_PRESENT it behaves like an exception.
    >
    > Ok.
    > There seem to be a bug in kvm_async_pf_task_wait(). Using
    > idle_cpu(cpu) to find out if the current task is the idle task may not
    > work if there is pending wake up. Me may schedule another task but
    > when that other task sleeps later we can't schedule back to idle until
    > the fault is completed.
    >
    > The right way is to use is_idle_task(current)
    But if there is pending wake up then scheduling to the waked up task is
    exactly what we want.

    --
    Gleb.


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