From owner-freebsd-stable@FreeBSD.ORG Wed Jul 23 19:17:33 2003 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4E11137B401 for ; Wed, 23 Jul 2003 19:17:33 -0700 (PDT) Received: from alcanet.com.au (mail3.alcanet.com.au [208.178.117.11]) by mx1.FreeBSD.org (Postfix) with ESMTP id A9B6943FBF for ; Wed, 23 Jul 2003 19:17:30 -0700 (PDT) (envelope-from peter.jeremy@alcatel.com.au) Received: from sydsmtp01.alcatel.com.au (IDENT:root@localhost.localdomain [127.0.0.1])h6O2HRvU021024; Thu, 24 Jul 2003 12:17:27 +1000 Received: from gsmx07.alcatel.com.au ([139.188.20.247]) by sydsmtp01.alcatel.com.au (Lotus Domino Release 5.0.12) with ESMTP id 2003072412172712:68446 ; Thu, 24 Jul 2003 12:17:27 +1000 Received: from gsmx07.alcatel.com.au (localhost [127.0.0.1]) by gsmx07.alcatel.com.au (8.12.9/8.12.9) with ESMTP id h6O2HQ7d083364; Thu, 24 Jul 2003 12:17:26 +1000 (EST) (envelope-from peter.jeremy@alcatel.com.au) Received: (from jeremyp@localhost) by gsmx07.alcatel.com.au (8.12.9/8.12.9/Submit) id h6O2HQ97083363; Thu, 24 Jul 2003 12:17:26 +1000 (EST) (envelope-from peter.jeremy@alcatel.com.au) Date: Thu, 24 Jul 2003 12:17:26 +1000 From: Peter Jeremy To: Brooks Davis Message-ID: <20030724021726.GJ430@gsmx07.alcatel.com.au> Mail-Followup-To: Brooks Davis , Matthias Buelow , freebsd-stable@freebsd.org References: <20030723173427.GA72876@vmunix.com> <20030723140329.C92624@carver.gumbysoft.com> <20030723221336.GA26555@pit.databus.com> <20030723223654.GA24008@moghedien.mukappabeta.net> <20030723224436.GD22166@Odin.AC.HMC.Edu> Mime-Version: 1.0 In-Reply-To: <20030723224436.GD22166@Odin.AC.HMC.Edu> User-Agent: Mutt/1.4.1i X-MIMETrack: Itemize by SMTP Server on SYDSMTP01/AlcatelAustralia(Release 5.0.12 |February 13, 2003) at 24/07/2003 12:17:27 PM,|February 13, 2003) at 24/07/2003 12:17:28 PM, Serialize complete at 24/07/2003 12:17:28 PM Content-Type: text/plain; charset=us-ascii Content-Disposition: inline cc: Matthias Buelow cc: freebsd-stable@freebsd.org Subject: Re: malloc does not return null when out of memory X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Jul 2003 02:17:33 -0000 On 2003-Jul-23 15:44:36 -0700, Brooks Davis wrote: >On Thu, Jul 24, 2003 at 12:36:54AM +0200, Matthias Buelow wrote: >> Wasn't there a sysctl flag to enable/disable overcommitting? >> I think I remember something but I can't find it; it might >> not have been on FreeBSD. > >No there isn't. Overcommit is a fundamental design feature of the BSD >VM. If you don't like it, find an OS that doesn't do it. The only one >I can think of off the top of my head in Irix where I've found it to be >a serious pain in the ass. DEC/Compaq/HP Tru64 has a flag to enable/disable overcommit. The major benefit seems to accrue to disk vendors with all the additional swap space needed. FreeBSD behaviour in the face of swap shortage is a regular and popular discussion topic. I suggest that a perusal of the archives will probably answer any questions. If anyone wishes to suggest a "solution" to FreeBSD's behaviour when there is a shortage of swap, please include patches. Peter