Re: [PATCH 07/15] watchdog: Allow runtime toggle of lockup detector affinity

From: Peter Zijlstra

Date: Wed Mar 25 2026 - 10:18:58 EST


On Wed, Mar 25, 2026 at 05:09:38PM +0800, Qiliang Yuan wrote:
> The hardlockup detector threads are affined to CPUs based on the
> HK_TYPE_TIMER housekeeping mask at boot. If this mask is updated at
> runtime, these threads remain on their original CPUs, potentially
> running on isolated cores.
>
> Synchronize watchdog thread affinity with HK_TYPE_TIMER updates.

Doesn't the normal watchdog run off of perf, using NMIs? How is that
TIMER?

And again, why do you think you need more than _ONE_ mask?

In the end, NOHZ_FULL needs all the masks to be the same anyway. There
is absolutely no sane reason to have this much configuration space.