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SubjectRe: [patch 1/2] Ignore stolen time in the softlockup watchdog


Jeremy Fitzhardinge wrote:
> Prarit Bhargava wrote:
>
>> I'd like to see this patch implement/fix touch_cpu_softlockup_watchdog
>> and touch_softlockup_watchdog to mimic touch_nmi_watchdog's behaviour.
>>
>
> Why? Is that more correct? It seems to me that you're interested in
> whether a specific CPU has gone and locked up. If touching the watchdog
>
> makes it update all CPU timestamps, then you'll hide the fact that other
> CPUs have locked up, won't it?
>
>
In case of misuse, yes. But there are cases where we know that all CPUs
will have softlockup issues, such as when doing a "big" sysrq-t dump.
When doing the sysrq-t we take the tasklist_lock which prevents all
other CPUs from scheduling -- this leads to bogus softlockup messages,
so we need to reset everyone's watchdog just before releasing the
tasklist_lock.

Another question -- are you going to expose disable/enable_watchdog to
other subsystems? Or are you going to expose touch_softlockup_watchdog?

> J
>
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