Re: [RFC][PATCH] avoid cpu hot remove of cpus which have special RTtasks.

[KAMEZAWA Hiroyuki]

On Fri, 16 Jun 2006 10:29:35 -0700
Ashok Raj <ashok.raj@xxxxxxxxx> wrote:
> Should we have this flag on a per-task so we know if this task should be 
> killed, or could be migrated without damage (assuming its going to run slow, 
> but nothing critically bad will happen)
> 
> Iam just worried if killing them globally without giving them a chance is 
> any good and favorite apps such as databases will have probably have
> ill effects.
> 
In the big servers which equips cpu-hotplug, apps should work as they designed.
If not, apps are already in buggy state.
IMHO, just stopping it is better than allowing execution in buggy state.

I used SIGSTOP. If a system admin or SIGCONT handler can modify cpu_allowed of
stopped thread, apps can go on. I think this is a realistic workaround.
(if the process is stopped, parent process of it can catch it by waitpid.)

p.s.
I think prefer cpu + allowed cpu will help this kind of probem, but there is no
interface..

-Kame

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