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SubjectRe: [PATCH 2/3] [RFC] time: Fix leapsecond triggered hrtimer/futex load spike issue


On 07/04/2012 02:21 AM, John Stultz wrote:
> As widely reported on the internet, some Linux systems after
> the leapsecond was inserted are experiencing futex related load
> spikes (usually connected to MySQL, Firefox, Thunderbird, Java, etc).
>
> An apparent for this issue workaround is running:
> $ date -s "`date`"
>
> Credit: http://www.sheeri.com/content/mysql-and-leap-second-high-cpu-and-fix
>
> I this issue is due to the leapsecond being added without
> calling clock_was_set() to notify the hrtimer subsystem of the
> change.
>
> The workaround functions as it forces a clock_was_set()
> call from settimeofday().
>
> This fix adds the required clock_was_set() calls to where
> we adjust for leapseconds.
>
> NOTE: This fix *depends* on the previous fix, which allows
> clock_was_set to be called from atomic context. Do not try
> to apply just this patch.
>
> CC: Prarit Bhargava <prarit@redhat.com>
> CC: stable@vger.kernel.org
> CC: Thomas Gleixner <tglx@linutronix.de>
> CC: linux@openhuawei.org
> Reported-by: Jan Engelhardt <jengelh@inai.de>
> Signed-off-by: John Stultz <johnstul@us.ibm.com>


Acked-by: Prarit Bhargava <prarit@redhat.com>

P.


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