Re: [PATCH] clocksource: Skip watchdog check for large watchdog intervals

From: Jiri Wiesner
Date: Thu Jan 04 2024 - 11:48:44 EST


On Thu, Jan 04, 2024 at 01:55:21PM +0800, Feng Tang wrote:
> On Wed, Jan 03, 2024 at 12:21:13PM +0100, Jiri Wiesner wrote:
> > Fixes: 2e27e793e280 ("clocksource: Reduce clocksource-skew threshold")
>
> IIUC, the issue could happen even before this commit? Though I do think
> this is good stuff for stable kernel.

Yes, it could happen before 2e27e793e280 but the threshold was so loose
that it probably was an extremely rare event. Commit 2e27e793e280 lowered
the threshold and this significantly increased the likelihood of skew
detection failing for large watchdog intervals. We got a report of a
kernel with 2e27e793e280 switching to the HPET but there were no failures
with a kernel without 2e27e793e280 on the same fleet of 8 NUMA node machines.

> 0Day robot reported some compiling issue.

I am going to submit a v2 of the patch fixing the error after we clarify
the jiffies concern.
--
Jiri Wiesner
SUSE Labs