Messages in this thread | | | Date | Tue, 20 Jan 2004 18:45:37 +1100 | From | Nick Piggin <> | Subject | Re: CPU Hotplug: Hotplug Script And SIGPWR |
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Tim Hockin wrote:
>On Tue, Jan 20, 2004 at 06:11:49PM +1100, Nick Piggin wrote: > >>I thought hotplug is allowed to fail? Thus you can have a hung system. >>Or what if the hotplug script itself becomes TASK_UNRUNNABLE? What if the >>process needs a guaranteed scheduling latency? >> > >I guess a hotplug script MAY fail. I don't think it's a good idea to make >your CPU hotplug script fail. May and Misght are different. It's up to the >implementor whether the script can get into a failure condition. >
Sorry bad wording. The script may fail to be executed.
> >The hotplug script can only become unrunnable if you yank out all the CPUs >on the system. I'd assume it would have an affinity of 0xffffffff. >
OK I guess thats not such a valid concern
> >What if <which> process needs guaranteed scheduling latency? Do we really >_guarantee_ scheduling latency *anywhere*? > >
We do guarantee that a realtime task won't be blocked waiting for a hotplug script to fault in and start it up again (which may not happen). Not sure how important this issue is.
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