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    SubjectRE: [PATCH] smp: Do not warn if smp_call_function_single() is doing a self call.
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    > From: Thomas Gleixner <tglx@linutronix.de>
    > Sent: Tuesday, April 16, 2019 1:13 PM
    > > ...
    > > True. And before we start digging deeper into this, let's step back: why
    > > do we need to do clockevents_unbind_device() on hybernation? Can we just
    > > disable the device and re-enable it back on resume?

    We do clockevents_unbind_device as part of hv_synic_cleanup(), which is
    called as a CPU hotplug callback: see vmbus_bus_init():
    ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hyperv/vmbus:online",
    hv_synic_init, hv_synic_cleanup);

    Yes, it looks the right thing is to implement the suspend/resume callbacks of
    the clock_event_device. Thank you for the suggestion! I'll look into this.

    > Yes. That's the right thing to do. Simple solution is to implement the
    > suspend/resume callbacks on the clock events device and be done with it.

    Agreed.

    > > Actually, all usages of clockevents_unbind_device() in kernel are
    > > limited to Hyper-V and with Michael's patches moving this out of VMBus
    > > driver I think it can go away completely.

    Thanks for the heads-up! I'll rebase to Michael's patches.

    > Correct. There was a driver which required that, but that's gone by now and
    > of course nobody noticed that it was the last user. The reason why this
    > exists was to allow switching out an active clocksource similar to the
    > sysfs unbind file but without user space interaction.
    >
    > tglx

    Thanks for the background sharing!

    - Dexuan

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