Re: [patch 13/20] timer: Switch to a non cascading wheel

From: Ingo Molnar
Date: Tue Jun 14 2016 - 06:11:58 EST



* Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:

> On Mon, 13 Jun 2016, Peter Zijlstra wrote:
> > On Mon, Jun 13, 2016 at 08:41:00AM -0000, Thomas Gleixner wrote:
> > > +
> > > + /* Cascading, sigh... */
> >
> > So given that userspace has no influence on timer period; can't we
> > simply fail to support timers longer than 30 minutes?
> >
> > In anything really arming timers _that_ long?
>
> Unfortunately yes. Networking being one of those. Real cascading happens once
> in a blue moon, but it happens.

So I'd really prefer it if we added a few more levels, a hard limit and got rid of
the cascading once and for all!

IMHO 'once in a blue moon' code is much worse than a bit more data overhead.

Thanks,

Ingo