Date: Wed, 23 May 2001 18:48:22 +0100 From: Brian Somers <brian@Awfulhak.org> To: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> Cc: Brian Somers <brian@Awfulhak.org>, freebsd-arch@FreeBSD.ORG, brian@Awfulhak.org Subject: Re: RFC: unit_list routines Message-ID: <200105231748.f4NHmMF08217@hak.lan.Awfulhak.org> In-Reply-To: Message from Garrett Wollman <wollman@khavrinen.lcs.mit.edu> of "Wed, 23 May 2001 13:11:45 EDT." <200105231711.NAA30721@khavrinen.lcs.mit.edu>
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> <<On Wed, 23 May 2001 16:52:58 +0100, Brian Somers <brian@Awfulhak.org> said:
>
> > The way I see it, holding and releasing mutexes will introduce
> > contention between consumers that only want to maintain a [completely
> > private] sparce array.
>
> I think the usual watchword is ``Don't optimize initialization.''
Maybe, but pessimising for no gains seems odd.
> > Allocating a ``struct resource'' munges a completely separate
> > resource (allocated units) in with all of the existing resources
>
> I'm having a bit of difficulty understanding the point you're trying
> to make here. It's a general interface; you need a subset of that
> functionality. Your resource is not ``munged [...] in with all of the
> existing resources'' -- each resource is managed separately, through
> its rman structure.
>
> > of lists and backwards pointers to achieve something that means
> > nothing in the context of these allocated units.
>
> Those lists and backwards pointers are not there for the benefit of
> clients, and should be treated as opaque. Actually, the whole `struct
> resource' should be treated as opaque, although because accessors are
> provided as macros rather than functions it can't be made literally
> so.
But they're required for the benefit of clients - so that they can
allocate existing resources, add and remove other resources etc.
I want a list of number ranges, not a resource management subsystem
that happens to manage number ranges for individual resources in a
way that could be bent to my needs.
> > Using bits when there are large numbers of units gets awkward.
>
> Just wrap it in macros. I almost posted an implementation with my
> last message, but decided that since it was so trivial it would be
> almost insulting for me to do so.
Not true - I'm too thick skinned to be insulted :oI
I'll look at a macro implementation.
> -GAWollman
--
Brian <brian@Awfulhak.org> <brian@[uk.]FreeBSD.org>
<http://www.Awfulhak.org>; <brian@[uk.]OpenBSD.org>
Don't _EVER_ lose your sense of humour !
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