* Igor Mammedov <imamm...@redhat.com> wrote:
> > I've seen that. Kernel still boots. With your patch it would hang.
Nonsense, not booting is OK when critical hardware is genuinely bad -
this isn't a disk drive or networking where bad IO 'happens sometimes'
and failure is something we have to engineer for - this is the CPU!
If a critical piece of hardware like the CPU or RAM is non-functional
then it should be excluded by the user explicitly, not worked around
after some ugly, non-deterministic and fragile timeout.
The timeout in the SMP bringup code was really an ancient property,
introduced back more than a decade ago when hardware makers were
ignorant of Linux we were ignorant of how to properly interface with
SMP hardware.
Today a 'timeout' means one of 3 things:
- bad, fragile hardware - this we don't want to hide, unless
explicitly told so by the user. I've seen such symptoms related to
overclocking for example - so not booting is perfectly justified,
it can prevent reporting a bogus kernel crash down the line.
- buggy SMP bringup. That is a bug that needs to be fixed, not
worked around.
- timeout fragility in virtualized environments
I'm not aware of any genuine case where timing out is the correct
thing to do.
So the patches look fine to me as-is, I planned on looking at them
more closely after the merge window.
Thanks,
Ingo
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