From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.12] helo=sc8-sf-mx2.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1Ct8sU-0002RK-4F for user-mode-linux-devel@lists.sourceforge.net; Mon, 24 Jan 2005 10:23:54 -0800 Received: from smtp002.mail.ukl.yahoo.com ([217.12.11.33]) by sc8-sf-mx2.sourceforge.net with smtp (Exim 4.41) id 1Ct8sQ-0002d9-BL for user-mode-linux-devel@lists.sourceforge.net; Mon, 24 Jan 2005 10:23:54 -0800 From: Blaisorblade Subject: Re: [uml-devel] memory References: <267988DEACEC5A4D86D5FCD780313FBB03B12C4B@exch-03.noida.hcltech.com> <41F36014.7050905@easyco.com> <200501230451.19196.rob@landley.net> In-Reply-To: <200501230451.19196.rob@landley.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200501241941.11211.blaisorblade@yahoo.it> Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Mon, 24 Jan 2005 19:41:10 +0100 To: user-mode-linux-devel@lists.sourceforge.net Cc: Rob Landley , Doug Dumitru , "Vaibhav Sharma, Noida" On Sunday 23 January 2005 10:51, Rob Landley wrote: > On Sunday 23 January 2005 03:28 am, Doug Dumitru wrote: > > Mr. Sharma, > > > > What you are trying to do will work, but not for large amounts of > > memory. UML runs the client using a single user mode memory block as > > the entire client's core. Thus the clients core size is limited to what > > a single task can allocate as plain memory. With x86 architechure cpus, > > this is 2G or 3G depending on how you build a kernel (but usually 2G). > > There are no paging mechanism here so there is no way to make it > > "gigabytes" > > > > Others can correct me if I have the exact numbers wrong. > > UML uses mmap (generally of a /tmp file) as physical memory. This can be > way bigger than physical memory on the machine, sure, and the parent kernel > will transparently use the mmaped file as backing store, demand paged and > all that. (Just like it would for any other application.) > > You could run out of virtual address space, though. Trying to map more > than a few gigabytes on a 32 bit machine is unlikely to work. > > Might I suggest buying a cheap x86-64 system (you can get 'em at Fry's a > couple hundred bucks), feed it a cheap 300 gigabyte IDE drive, and have > fun. This is not (yet) exactly supported... a lot of work is going on this, and somebody was even able to compile and run (successfully?) some x86_64 umls... However, consider it still as a developer-only tool for now. 2.6.11 could effectively be a good x86_64 tree, but do not yet use it for anything critical. Clearly, 32-bit UMLs run well on x86_64 boxes, but don't have the 64-bit advantages... -- Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 http://www.user-mode-linux.org/~blaisorblade ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel