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    Subject[patch 086/149] xen: ensure timer tick is resumed even on CPU driving the resume
    2.6.32-stable review patch.  If anyone has any objections, please let us know.


    From: Ian Campbell <>

    commit cd52e17ea8278f8449b6174a8e5ed439a2e44ffb upstream.

    The core suspend/resume code is run from stop_machine on CPU0 but
    parts of the suspend/resume machinery (including xen_arch_resume) are
    run on whichever CPU happened to schedule the xenwatch kernel thread.

    As part of the non-core resume code xen_arch_resume is called in order
    to restart the timer tick on non-boot processors. The boot processor
    itself is taken care of by core timekeeping code.

    xen_arch_resume uses smp_call_function which does not call the given
    function on the current processor. This means that we can end up with
    one CPU not receiving timer ticks if the xenwatch thread happened to
    be scheduled on CPU > 0.

    Use on_each_cpu instead of smp_call_function to ensure the timer tick
    is resumed everywhere.

    Signed-off-by: Ian Campbell <>
    Acked-by: Jeremy Fitzhardinge <>
    Signed-off-by: Greg Kroah-Hartman <>

    arch/x86/xen/suspend.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    --- a/arch/x86/xen/suspend.c
    +++ b/arch/x86/xen/suspend.c
    @@ -60,6 +60,6 @@ static void xen_vcpu_notify_restore(void

    void xen_arch_resume(void)
    - smp_call_function(xen_vcpu_notify_restore,
    - (void *)CLOCK_EVT_NOTIFY_RESUME, 1);
    + on_each_cpu(xen_vcpu_notify_restore,
    + (void *)CLOCK_EVT_NOTIFY_RESUME, 1);

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      Last update: 2010-07-01 20:47    [W:0.020 / U:64.584 seconds]
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