Re: CPU Hotplug: Hotplug Script And SIGPWR

Srivatsa Vaddagiri
2004-01-21T04:01:55Z

On Tue, Jan 20, 2004 at 12:43:52AM -0800, Tim Hockin wrote:
> IFF the app is designed to handle it. The existence of a SIGPWR handler
> does not necessarily imply that, though. a SIGCPU or something might
> correlate 1:1 with this, but SIGPWR doesn't.

I agree we should have a separe signal for CPU Hotplug. By default the signal
will be ignored, unless a task registers a signal handler for that special
signal.

That way, tasks which "knowingly" change their CPU affinity will be able to
tackle a CPU going down by handling the signal (probably change their CPU
affinity again), while tasks which have their CPU affinity changed "unknowingly"
(by other tasks) will just ignore the signal. The hotplug script interface
allows the admin to go and change the CPU affinity again for the second class
of tasks, if needed.

The only problem with a new signal is conformance to standards (if any).

--

Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017