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    SubjectRe: [patch 61/66] timers: Convert to hotplug state machine
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    Hi Richard,

    On 26/07/16 16:42, rcochran@linutronix.de wrote:
    > Jon,
    >
    > On Mon, Jul 25, 2016 at 03:56:48PM +0100, Jon Hunter wrote:
    >>> When tearing down, call timers_dead_cpu before notify_dead.
    >>> There is a hidden dependency between:
    >>>
    >>> - timers
    >>> - Block multiqueue
    >>> - rcutree
    >>>
    >>> If timers_dead_cpu() comes later than blk_mq_queue_reinit_notify()
    >>> that latter function causes a RCU stall.
    >>
    >> After this change is applied I am seeing RCU stalls during suspend
    >> on Tegra. I guess I am hitting the case mentioned above? How should
    >> this be avoided?
    >
    > Contrary to the commit message, this callback ended up in the wrong
    > place within the sequence. (It was correct in an earlier version, but
    > the series has been through many changes.)
    >
    > Can you try this patch to see if it avoids the stall, please?

    I have included the patch and I am no longer seeing any RCU stalls and
    so this does look like it fixed it.

    Thanks!
    Jon

    --
    nvpublic

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