From owner-freebsd-hackers Sat Jul 6 15: 7:36 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0AD6C37B405 for ; Sat, 6 Jul 2002 15:07:29 -0700 (PDT) Received: from srv1.cosmo-project.de (srv1.cosmo-project.de [213.83.6.106]) by mx1.FreeBSD.org (Postfix) with ESMTP id ED90B43E09 for ; Sat, 6 Jul 2002 15:07:27 -0700 (PDT) (envelope-from ticso@cicely5.cicely.de) Received: from cicely5.cicely.de (cicely5.cicely.de [IPv6:3ffe:400:8d0:301:200:92ff:fe9b:20e7]) (authenticated bits=0) by srv1.cosmo-project.de (8.12.3/8.12.3) with ESMTP id g66M7MMa017311 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=OK); Sun, 7 Jul 2002 00:07:25 +0200 (CEST) (envelope-from ticso@cicely5.cicely.de) Received: from cicely5.cicely.de (localhost [IPv6:::1]) by cicely5.cicely.de (8.12.1/8.12.1) with ESMTP id g66M7LFJ045423 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Sun, 7 Jul 2002 00:07:21 +0200 (CEST)?g (envelope-from ticso@cicely5.cicely.de) Received: (from ticso@localhost) by cicely5.cicely.de (8.12.1/8.12.1/Submit) id g66M7Kw0045422; Sun, 7 Jul 2002 00:07:20 +0200 (CEST)?g (envelope-from ticso) Date: Sun, 7 Jul 2002 00:07:20 +0200 From: Bernd Walter To: Darren Pilgrim Cc: ticso@cicely.de, freebsd-hackers@FreeBSD.ORG Subject: Re: How does swap work address spacewise? Message-ID: <20020706220720.GG23704@cicely5.cicely.de> Reply-To: ticso@cicely.de References: <20020705113532.GA11273@atrbg11.informatik.tu-muenchen.de> <20020705133515.GA295@HAL9000.wox.org> <20020705133837.GA513@HAL9000.wox.org> <20020705234126.GA12183@atrbg11.informatik.tu-muenchen.de> <3D2640A7.3EA2236B@pantherdragon.org> <20020706020656.GL48977@cicely5.cicely.de> <3D2762FE.9D9E0378@pantherdragon.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3D2762FE.9D9E0378@pantherdragon.org> X-Operating-System: FreeBSD cicely5.cicely.de 5.0-CURRENT i386 User-Agent: Mutt/1.5.1i Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sat, Jul 06, 2002 at 02:37:02PM -0700, Darren Pilgrim wrote: > Bernd Walter wrote: > > On Fri, Jul 05, 2002 at 05:58:15PM -0700, Darren Pilgrim wrote: > > > If RAM + swap can be more than 4GB, how does FreeBSD address swap on a > > > 32-bit machine? Does the kernel internally use a wider address space > > > > The same way it does on every partitition: using block numbers. > > That way you can address 1TByte. > > I thought the limit for filesystems was 2TB? The Blocknumber is signed that gives: 2^31 * 512Bytes > > And you can have more than a single swap partition. > > Up to four, so then the theoretical limit for swap is 8TB? 4 is just a default. [61]cicely9# swapinfo Device 1K-blocks Used Avail Capacity Type /dev/da1b 105472 80 105392 0% Interleaved /dev/da11b 174880 0 174880 0% Interleaved /dev/da4b 211456 0 211456 0% Interleaved /dev/da5b 211456 0 211456 0% Interleaved /dev/da6b 211456 0 211456 0% Interleaved /dev/da7b 211456 0 211456 0% Interleaved /dev/da8b 211456 0 211456 0% Interleaved /dev/da9b 211456 0 211456 0% Interleaved /dev/da10b 211456 0 211456 0% Interleaved Total 1760544 80 1760464 0% The limit here is the maximum number of harddisks, which is IIRC 512 per driver. This cames from the available minor bits in the device node. > > In reality managementstructures which have to be in kernel addressspace > > is limiting swap before. > > Do these management structures grow as swap grows, or do they only > change as the utilization increases? AFAIK there is a static part. Possible not memory but only KVM addressspace. Also AFAIK it makes a difference if you allocate the same space using a single partition or in more than one. -- B.Walter COSMO-Project http://www.cosmo-project.de ticso@cicely.de Usergroup info@cosmo-project.de To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message