Re: [PATCH sched-devel 0/7] CPU isolation extensions

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Fri, 2008-02-22 at 08:38 -0500, Mark Hounschell wrote:

> >> List of commits
> >>    cpuisol: Make cpu isolation configrable and export isolated map
> >  
> > cpu_isolated_map was a bad hack when it was introduced, I feel we should
> > deprecate it and fully integrate the functionality into cpusets. That would
> > give a much more flexible end-result.
> > 
> > CPU-sets can already isolate cpus by either creating a cpu outside of any set,
> > or a set with a single cpu not shared by any other sets.
> > 
> 
> Peter, what about when I am NOT using cpusets and are disabled in my config but
> I still want to use this?

Then you enable it?

> >>    cpuisol: Do not schedule workqueues on the isolated CPUs
> >  
> > (per-cpu workqueues, the single ones are treated in the previous section)
> > 
> > I still strongly disagree with this approach. Workqueues are passive, they
> > don't do anything unless work is provided to them. By blindly not starting them
> > you handicap the system and services that rely on them.
> > 
> 
> Have things changed since since my first bad encounter with Workqueues.
> I am referring to this thread. 
> 
> http://kerneltrap.org/mailarchive/linux-kernel/2007/5/29/97039 

Just means you get to fix those problems. By blindly not starting them
you introduce others.