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To: "Garrett A. Wollman" <wollman@lcs.mit.edu>
cc: Peter Wemm <peter@jhome.dialix.com>, Bruce Evans <bde@zeta.org.au>,
        CVS-commiters@freefall.freebsd.org, cvs-sys@freefall.freebsd.org
Subject: Re: cvs commit: src/sys/kern kern_sysctl.c 
In-reply-to: Your message of "Wed, 15 Nov 1995 11:41:59 EST."
             <9511151641.AA26165@halloran-eldar.lcs.mit.edu> 
Date: Wed, 15 Nov 1995 17:55:22 +0100
Message-ID: <3126.816454522@critter.tfs.com>
From: Poul-Henning Kamp <phk@critter.tfs.com>
Sender: owner-commit@FreeBSD.ORG
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> <<On Wed, 15 Nov 1995 10:19:27 +0100, Poul-Henning Kamp <phk@critter.tfs.com>
 said:
> 
> > The old implementation would lock the (old,oldlen) so that it could
> > do the copyout without a context-switch.
> 
> > In all cases but kern.vnode.
> 
> > I really hate that exception, but on the other hand I'm not sure I really
> > think we should have that feature anyway.  It's going to be quite an effort
> > to implement atomicity on a SMP system, and I really don't think it is the
> > right way to solve the problem.  I can see that it's a lot easier in the
> > user-land, but boy is it a mess in the kernel.
> 
> The purpose of this is to prevent race conditions even in a
> uniprocessor system.

what race-conditions ?


--
Poul-Henning Kamp           | phk@FreeBSD.ORG       FreeBSD Core-team.
http://www.freebsd.org/~phk | phk@login.dknet.dk    Private mailbox.
whois: [PHK]                | phk@ref.tfs.com       TRW Financial Systems, Inc.
Future will arrive by its own means, progress not so.