From owner-p4-projects@FreeBSD.ORG  Thu Sep 27 21:24:06 2007
Return-Path: <owner-p4-projects@FreeBSD.ORG>
Delivered-To: p4-projects@freebsd.org
Received: by hub.freebsd.org (Postfix, from userid 32767)
	id F3AB316A46D; Thu, 27 Sep 2007 21:24:05 +0000 (UTC)
Delivered-To: perforce@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id AE03216A420;
	Thu, 27 Sep 2007 21:24:05 +0000 (UTC)
	(envelope-from jb@what-creek.com)
Received: from what-creek.com (what-creek.com [66.111.37.70])
	by mx1.freebsd.org (Postfix) with ESMTP id 73CC913C455;
	Thu, 27 Sep 2007 21:24:05 +0000 (UTC)
	(envelope-from jb@what-creek.com)
Received: by what-creek.com (Postfix, from userid 102)
	id 48A4F73180; Thu, 27 Sep 2007 21:09:07 +0000 (GMT)
Date: Thu, 27 Sep 2007 21:09:07 +0000
From: John Birrell <jb@what-creek.com>
To: John Baldwin <jhb@freebsd.org>
Message-ID: <20070927210907.GA76906@what-creek.com>
References: <200709270957.l8R9vv81089001@repoman.freebsd.org>
	<200709270937.44791.jhb@freebsd.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <200709270937.44791.jhb@freebsd.org>
User-Agent: Mutt/1.4.2.3i
Cc: Perforce Change Reviews <perforce@freebsd.org>
Subject: Re: PERFORCE change 126859 for review
X-BeenThere: p4-projects@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: p4 projects tree changes <p4-projects.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/p4-projects>,
	<mailto:p4-projects-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/p4-projects>
List-Post: <mailto:p4-projects@freebsd.org>
List-Help: <mailto:p4-projects-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/p4-projects>,
	<mailto:p4-projects-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 27 Sep 2007 21:24:06 -0000

On Thu, Sep 27, 2007 at 09:37:44AM -0400, John Baldwin wrote:
> How about doing something like this:
> 
> 	struct thread {
> 		...
> 		char td_dtrace_data[KDTRACE_THREAD_SIZE];
> 	};
> 
> Then you don't have to allocate it separately or maintain specific offsets
> variables, etc. and using it can become easier.

I thought about doing that, but it involves changing the size of struct thread.

The approach I'm taking will allow the addition of DTrace to both
the RELENG_6 and RELENG_7 trees because it maintains binary compatibility.

I figure if it has to be opaque then it might as well be so opaque that
other code just doesn't see it.

--
John Birrell