Re: [PATCH 1/2] nohz: Fix again collision between tick and other hrtimers

From: Rik van Riel
Date: Thu Apr 20 2017 - 12:01:51 EST


On Thu, 2017-04-20 at 17:30 +0200, Frederic Weisbecker wrote:
> (This restores commit 24b91e360ef521a2808771633d76ebc68bd5604b that
> got
> reverted by commit 558e8e27e73f53f8a512485be538b07115fe5f3c due to a
> regression where CPUs spuriously stopped ticking. The issue happened
> when a tick fired too early past its expected expiration: on IRQ exit
> the tick was scheduled again to the same deadline but skipped
> reprogramming because ts->next_tick still kept in cache the deadline.
> This has been fixed now with resetting ts->next_tick from the tick
> itself. Extra care has also been taken to prevent from obsolete
> values
> throughout CPU hotplug operations.)
>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>