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SubjectRe: [GIT PULL] nohz: Fix double clock write on idle ticks
* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> From: Frederic Weisbecker <fweisbec@gmail.com>
>
> Ingo,
>
> Please pull the nohz/drop-double-write-v3 branch that can be found at:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
> nohz/drop-double-write-v3
>
> Although the 1st patch fixes a bug, it was a longstanding issue so
> that branch doesn't need to be applied in 3.17. The next merge window
> looks better.
>
> --
> The tick reschedules itself unconditionally. It's relevant in periodic
> mode but not in dynticks mode where it results in spurious double clock
> writes and even spurious periodic behaviour for low-res case.
>
> This set fixes that:
>
> * 1st patch removes low-res periodic tick rescheduling in nohz mode.
> This fixes spurious periodic behaviour.
>
> * 2nd patch does the same for high-res mode. Here there is no such
> spurious periodic behaviour but it still spares a double clock write
> in some cases.
> ---
>
>
> Thanks,
> Frederic
> ---
>
> Viresh Kumar (2):
> nohz: Fix spurious periodic tick behaviour in low-res dynticks mode
> nohz: Avoid tick's double reprogramming in highres mode
>
>
> kernel/time/tick-sched.c | 8 ++++++++
> 1 file changed, 8 insertions(+)

These fixes are pretty small - any objections against putting it into
timers/urgent and including it in v3.17?

Thanks,

Ingo


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