Re: [PATCH] watchdog/hardlockup: Avoid large stack frames in watchdog_hardlockup_check()

From: Michal Hocko
Date: Wed Aug 02 2023 - 03:27:35 EST

On Tue 01-08-23 08:41:49, Doug Anderson wrote:
> Ah, I see what you mean. The one issue I have with your solution is
> that the ordering of the stack crawls is less ideal in the "dump all"
> case when cpu != this_cpu. We really want to see the stack crawl of
> the locked up CPU first and _then_ see the stack crawls of other CPUs.
> With your solution the locked up CPU will be interspersed with all the
> others and will be harder to find in the output (you've got to match
> it up with the "Watchdog detected hard LOCKUP on cpu N" message).
> While that's probably not a huge deal, it's nicer to make the output
> easy to understand for someone trying to parse it...

Is it worth to waste memory for this arguably nicer output? Identifying
the stack of the locked up CPU is trivial.
Michal Hocko