Re: CPU Hotplug: Hotplug Script And SIGPWR

Matthias Urlichs
2004-01-21T15:07:53Z

Hi, Tim Hockin wrote:

> We already can not handle unexpected CPU removals gracefully, correct? So
> we expect some user-provided notification, right?
>
Well, if the CPU is executing userland (or idling), we conceivably could.
That would kill off one userspace process (which might be able to recover
given a signal and longjmp(), but such is life. ;-)

> So force userland to handle it before we give the OK to remove a CPU.

I like the idea of an "unrunnable" queue, that way you have the option to
fix the problem afterwards -- or just ignore it, if you decide it's OK for
processes to wait a few minutes while you replace the failing CPU fan.

It's like mount(). Usually you unmount cleanly, but sometimes you use -f
and something becomes inaccesible. At least WRT CPUs, the inaccessibility
is (usually) fixable. (I wish it were so, WRT NFS mounts.)

--
Matthias Urlichs | {M:U} IT Design @ m-u-it.de | smurf@smurf.noris.de
Disclaimer: The quote was selected randomly. Really. | http://smurf.noris.de
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