From: Erich Focht <efocht@hpce.nec.com>
To: colpatch@us.ibm.com
Subject: Re: [Lse-tech] [RFC PATCH] scheduler: Dynamic sched_domains
Date: Sun, 10 Oct 2004 14:45:58 +0200
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On Saturday 09 October 2004 03:05, Matthew Dobson wrote:
> On Fri, 2004-10-08 at 15:51, Erich Focht wrote:
> > We're building this from bottom (cpus) up and need to take care of the
> > unlinking of the global domain when inserting something. But otherwise
> > this could be sufficient.
> 
> I personally like to think of it from the top down.  The internal API I
> came up with looks like:
> 
> create_domain(parent_domain, type);
> destroy_domain(domain);
> add_cpu_to_domain(cpu, domain);
> 
> So you basically build your domain from the top down, from your 1 or
> more top-level domains, down to your lowest level domains.  You then add
> cpus (1 or more per domain) to the leaf domains in the tree you built. 
> Those cpus cascade up the tree, and the whole tree knows exactly which
> cpus are contained in each domain in it.
> 
> I think these are the three main functions you need to construct pretty
> much any conceivable, useful sched_domains hierarchy.

I'd suggest adding:
reparent_domain(domain, new_parent_domain);

When I said that the domains tree is standing on its leaves I meant
that the core components are the CPUs. Or the Nodes, if you already
have them. Or some supernodes, if you already have them. In a "normal"
filesystem you have the root directory, create subdirectories and
create files in them. Here you already have the files but not the
structure (or the simplest possible structure).

Anyhow, the 4 command API can well be the guts of the directory
operations API which I proposed.

Regards,
Erich

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