Re: [PATCH] nohz: Fix collision between tick and other hrtimers
From: Frederic Weisbecker
Date: Mon Dec 26 2016 - 11:40:30 EST
On Sun, Dec 25, 2016 at 09:56:57PM -0500, Rik van Riel wrote:
> On Sat, 2016-12-24 at 17:15 +0100, Frederic Weisbecker wrote:
> > When the tick is stopped and an interrupt occurs afterward, we check
> > on
> > that interrupt exit if the next tick needs to be rescheduled. If it
> > doesn't need any update, we don't want to do anything.
> > In order to check if the tick needs an update, we compare it against
> > the
> > clockevent device deadline. Now that's a problem because the
> > clockevent
> > device is at a lower level than the tick itself if it is implemented
> > on top of hrtimer.
> Ohhhhh, good find. That is one subtle bug.
Oh yeah, it took me several month to debug that one :-) !
> Acked-by: Rik van Riel <riel@xxxxxxxxxx>
> All Rights Reversed.