Re: [GIT PULL] nohz: Bunch of fixes

From: Ingo Molnar
Date: Sat May 04 2013 - 02:42:01 EST



* Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:

> Ingo,
>
> Please pull the timers/nohz-hz1 branch that can be found at:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
> timers/nohz-hz1
>
> HEAD: a7f4d69bb1d5e1f573b680355a2ad51566338887
>
> It fixes a Kconfig dependency issue and forces a minimum of 1 tick every seconds
> to keep handling the scheduler_tick() duties, even at a very low granularity. This
> is a workaround until we can handle all these duties through on-demand driven
> solutions rather than using periodic events, as per your suggestion.
>
> I just noted two things:
>
> * update_cpu_load_active() seem to rely on the fixed periodic tick at the
> HZ rate. There is certainly something to tweak there to make it really correct
> with dynamick ticks. I have the feeling that modifying pending_updates won't work
> as it seems to decay assuming the time to catch up was idle.
>
> * I'll probably have to disable CONFIG_CFS_BANDWIDTH when full dynticks
> is enabled. First of all it modifies rq->nr_running without using inc/dec_nr_running
> standard API, which is required for full dynticks. And second, I need to triple
> check it's safe to use with 1 tick per second.
>
> Ah and please note the merge commit (c032862fba51a3ca504752d3a25186b324c5ce83)
> that was needed to get latest RCU and sched updates for the Kconfig fix.
>
> Thanks,
> Frederic
> ---
>
> Frederic Weisbecker (2):
> rcu: Fix full dynticks' dependency on wide RCU nocb mode
> sched: Keep at least 1 tick per second for active dynticks tasks
>
>
> include/linux/sched.h | 1 +
> init/Kconfig | 4 ++--
> kernel/sched/core.c | 30 ++++++++++++++++++++++++++++++
> kernel/sched/idle_task.c | 1 +
> kernel/sched/sched.h | 10 ++++++++++
> kernel/time/Kconfig | 1 -
> kernel/time/tick-sched.c | 7 +++++++
> 7 files changed, 51 insertions(+), 3 deletions(-)

Pulled, thanks Frederic!

Ingo
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