Date: Thu, 7 Oct 2004 01:59:12 -0700
From: Paul Jackson <pj@sgi.com>
To: colpatch@us.ibm.com
Cc: Simon.Derr@bull.net, mbligh@aracnet.com, pwil3058@bigpond.net.au,
       frankeh@watson.ibm.com, dipankar@in.ibm.com, akpm@osdl.org,
       ckrm-tech@lists.sourceforge.net, efocht@hpce.nec.com,
       lse-tech@lists.sourceforge.net, hch@infradead.org, steiner@sgi.com,
       jbarnes@sgi.com, sylvain.jeaugey@bull.net, djh@sgi.com,
       linux-kernel@vger.kernel.org, ak@suse.de, sivanich@sgi.com
Subject: Re: [ckrm-tech] Re: [Lse-tech] [PATCH] cpusets - big numa cpu and
 memory placement
Message-Id: <20041007015912.3da745a9.pj@sgi.com>
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Matthew wrote:
> > Perhaps these flags should be called:
> > 	mems_exclusive_precursor
> > 	cpus_exclusive_precursor
> > ;).
> 
> Ok...  So if we could offer the 'real' exclusion that the PBS and LSF
> workload managers offer directly, would that suffice?  Meaning, could we
> make PBS and LSF work on top of in-kernel mechanisms that offer 'real'
> exclusion.  'Real' exclusion defined as isolated groups of CPUs and
> memory that the kernel can guarantee will not run other processes?  That
> way we can get the job done without having to rely on these external
> workload managers, and be able to offer this dynamic partitioning to all
> users.  Thoughts?


I agree entirely.  Before when I was being a penny pincher about
how much went in the kernel, it might have made sense to have
the mems_exclusive and cpus_exclusive precursor flags.

But now that we have demonstrated a bone fide need for a really
really exclusive cpuset, it was silly of me to consider offering:

> > 	mems_exclusive_precursor
> > 	cpus_exclusive_precursor
> >     really_really_exclusive

These multiple flavors just confuse and annoy.

You're right.  Just one flag option, for the really exclusive cpuset,
is required here.

A different scheduler domain (whether same scheduler with awareness of
the boundaries, or something more substantially distinct) may only be
attached to a cpuset if it is exclusive.

-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@sgi.com> 1.650.933.1373
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