Re: [PATCH 0/2] nohz: Deal with clock reprogram skipping issues v3

From: Frederic Weisbecker
Date: Tue May 23 2017 - 09:10:59 EST


On Tue, May 23, 2017 at 09:25:08AM +0200, Ingo Molnar wrote:
>
> * Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:
>
> > v2 had issues on -tip tree and triggered a warning. It seems to have
> > disappeared. Perhaps it was due to another timer issue. Anyway this
> > version brings more debugging informations, with a layout that is more
> > bisection-friendly and it also handles ticks that fire outside IRQ
> > context and thus carry NULL irq regs. This happen when
> > hrtimer_interrupt() is called on hotplug cpu down for example.
> >
> > We'll see if the issue arises again.
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
> > nohz/fixes
> >
> > HEAD: cd15f46b284f04dbedd065a9d99a4e0badae379a
> >
> > Thanks,
> > Frederic
> > ---
> >
> > Frederic Weisbecker (2):
> > nohz: Add hrtimer sanity check
> > nohz: Fix collision between tick and other hrtimers, again
> >
> >
> > kernel/time/tick-sched.c | 48 +++++++++++++++++++++++++++++++++++++++++++-----
> > kernel/time/tick-sched.h | 2 ++
> > 2 files changed, 45 insertions(+), 5 deletions(-)
>
> So I think the 3 commits queued up right now:
>
> 99fa871820cf: nohz: Reset next_tick cache even when the timer has no regs
> 411fe24e6b7c: nohz: Fix collision between tick and other hrtimers, again
> ce6cf9a15d62: nohz: Add hrtimer sanity check
>
> are OK and I'd not rebase them unless there's some breakage.
>
> One thing I noticed: your second series does appear to have:
>
> 99fa871820cf: nohz: Reset next_tick cache even when the timer has no regs
>
> is that intentional? That is pretty much the only commit I'd love to rebase with a
> proper description added.

Yes in my latest series I melted "nohz: Reset next_tick cache even when the timer has no regs"
into "nohz: Fix collision between tick and other hrtimers, again" because it's a fixup and
keeping that patch separate may break bisection.

So ideally, it would be nice if you could fixup 411fe24e6b7c with 99fa871820cf. That's roughly
all I did in my latest series.

Thanks!