From owner-freebsd-arch@FreeBSD.ORG  Sat Mar 25 07:47:41 2006
Return-Path: <owner-freebsd-arch@FreeBSD.ORG>
X-Original-To: freebsd-arch@FreeBSD.org
Delivered-To: freebsd-arch@FreeBSD.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id EE19F16A400;
	Sat, 25 Mar 2006 07:47:41 +0000 (UTC)
	(envelope-from phk@critter.freebsd.dk)
Received: from pasmtp.tele.dk (pasmtp.tele.dk [193.162.159.95])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 927C243D45;
	Sat, 25 Mar 2006 07:47:41 +0000 (GMT)
	(envelope-from phk@critter.freebsd.dk)
Received: from critter.freebsd.dk (0x535c0e2a.sgnxx1.adsl-dhcp.tele.dk
	[83.92.14.42]) by pasmtp.tele.dk (Postfix) with ESMTP id AC4061EC318;
	Sat, 25 Mar 2006 08:47:40 +0100 (CET)
Received: from critter.freebsd.dk (localhost [127.0.0.1])
	by critter.freebsd.dk (8.13.4/8.13.4) with ESMTP id k2P7ldZr062793;
	Sat, 25 Mar 2006 08:47:40 +0100 (CET)
	(envelope-from phk@critter.freebsd.dk)
To: John-Mark Gurney <gurney_j@resnet.uoregon.edu>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Fri, 24 Mar 2006 20:51:49 PST."
	<20060325045149.GA7001@funkthat.com> 
Date: Sat, 25 Mar 2006 08:47:39 +0100
Message-ID: <62792.1143272859@critter.freebsd.dk>
Sender: phk@critter.freebsd.dk
Cc: Jason Evans <jasone@FreeBSD.org>, freebsd-arch@FreeBSD.org
Subject: Re: Proposed addition of malloc_size_np() 
X-BeenThere: freebsd-arch@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussion related to FreeBSD architecture <freebsd-arch.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arch>
List-Post: <mailto:freebsd-arch@freebsd.org>
List-Help: <mailto:freebsd-arch-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 25 Mar 2006 07:47:42 -0000

In message <20060325045149.GA7001@funkthat.com>, John-Mark Gurney writes:

>a) the idea of using memory beyond what you've allocated is bad...

Not if you get permission.

>b) it should return the maximum size you can realloc to w/o a copy
>of the memory...  and then the way you use the extra memory is to
>call realloc on the buffer to the value returned by malloc_size_np..

This is not an easy number to return, and it is dynamic.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.