WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Memory question (again)

To: "Tvrtko A. Uršulin" <tvrtko@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Memory question (again)
From: Ian Pratt <Ian.Pratt@xxxxxxxxxxxx>
Date: Wed, 12 Nov 2003 14:32:49 +0000
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxxx, Ian.Pratt@xxxxxxxxxxxx
Delivery-date: Wed, 12 Nov 2003 14:34:40 +0000
Envelope-to: steven.hand@xxxxxxxxxxxx
In-reply-to: Your message of "Wed, 12 Nov 2003 12:55:04 +0100." <200311121255.04731.tvrtko@xxxxxxxxxxxx>
List-archive: <http://sourceforge.net/mailarchive/forum.php?forum=xen-devel>
List-help: <mailto:xen-devel-request@lists.sourceforge.net?subject=help>
List-id: List for Xen developers <xen-devel.lists.sourceforge.net>
List-post: <mailto:xen-devel@lists.sourceforge.net>
List-subscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=subscribe>
List-unsubscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=unsubscribe>
Sender: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx
> 
> I still don't understand how memory management for guest OSs work. 
> 
> What exactly is the size given to xi_create? I mean, is it the minimum 
> guaranteed size (if so, where is the absolute maximum set), or is it the 
> absoulte maximum guest can use?

When the guest Linux boots, it sizes and initialises it's mem_map
array based on the number of pages that are available to it at
startup. Thus, it effectively determines the maximum size of
memory that the domain can ever have (we could in principle use
the new Linux support for "hot swappable" memory to enable the
mem_map array to be extended, but we've yet to do this and aren't
keen).

What might be a sensible improvement to the current tools would
be the ability to be able to start a domain with less memory than
its maximum size. We could do this by having the balloon driver
grab frames very early in the boot sequence, before the domain
adds them to its free list.

This is something to consider when we update the tools for
controlling the balloon driver.

Ian


-------------------------------------------------------
This SF.Net email sponsored by: ApacheCon 2003,
16-19 November in Las Vegas. Learn firsthand the latest
developments in Apache, PHP, Perl, XML, Java, MySQL,
WebDAV, and more! http://www.apachecon.com/
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel

<Prev in Thread] Current Thread [Next in Thread>