Re: [Query] Can we use normal timers (kernel/timer.c) while in NO_HZ_FULL mode?

[Frederic Weisbecker]

On Wed, Jun 04, 2014 at 07:14:43PM +0530, Viresh Kumar wrote:
> On 4 June 2014 18:53, Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:
> > Right, if we enqueue a timer when the tick is stopped, we call wake_up_nohz_cpu().
> 
> Ahh, I looked at __mod_timer() :)
> 
> BTW, shouldn't we do something similar for mod_timer_pinned()
> as well ?

Ah that looks right. In fact we should probably move the wake_up_nohz_cpu()
to internal_add_timer().

And that concerns nohz idle as well. If mod_timer() selects a CPU that doesn't
appear to be idle in get_nohz_timer_target() but then becomes idle afterward
before we lock its timer base, the CPU may well miss the timer.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/