Re: [RFC] cpuset: add interface to isolated cpus

[Paul Jackson <pj@sgi.com>]

Nick wrote:
> Well, it was supposed to be used for sched-domains partitioning, and
> its uselessness for anything else I guess is what threw me.

The use of cpu_exclusive for sched domain partitioning was added
later, by a patch from Dinikar, in April or May of 2005.

In hindsight, I think I made a mistake in agreeing to, and probably
encouraging, this particular overloading of cpu_exclusive.  I had
difficulty adequately understanding what was going on.

Granted, as we've noted elsewhere on this thread, the cpu_exclusive
flag is underutilized.  It gives cpusets so marked a certain limited
exclusivity to its cpus, relative to its siblings, but it doesn't do
much else, other than this controversial partitioning of sched domains.

There may well be a useful role for the cpu_exclusive flag in managing
sched domains and partitioning.  The current role is flawed, in my view.

-- 
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                  Paul Jackson <pj@sgi.com> 1.925.600.0401