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

[KAMEZAWA Hiroyuki]

On 16 Jun 2006 11:14:57 +0200
Andi Kleen <ak@xxxxxxx> wrote:

> KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> writes:
> > 
> > This is a bit pessimistic. But forecd migration of RT task which is bounded
> > to the special cpu will cause unpredictable trouble, I think.
> 
> More trouble than running it on a CPU that is about to fail?
> Doubtful.
> 
With my patch, RT tasks will continute to run.

Assume there are some multi-threaded tasks with SCHED_FIFO.
If they uses some kind of synchronization in user land and task is migrated to
other cpus, it will cause dead-lock.


> It seems like a case of "never check for an error you don't know
> how to handle"
> 

"Dont' migrate a task which may fall in dead-lock if it run on another cpu."

-Kame

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