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] Re: lazy context switching

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] Re: lazy context switching
From: Hollis Blanchard <hollisb@xxxxxxxxxx>
Date: Tue, 30 Aug 2005 11:22:48 -0500
Cc: Dan Magenheimer <dan.magenheimer@xxxxxx>
Delivery-date: Tue, 30 Aug 2005 16:22:02 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <loom.20050830T172319-895@xxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Organization: IBM Linux Technology Center
References: <200508251655.09988.hollisb@xxxxxxxxxx> <32738a7d711e6cf6815ae0ef6f2994f9@xxxxxxxxxx> <loom.20050830T172319-895@xxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: KMail/1.8.2
On Tuesday 30 August 2005 10:25, Dan Magenheimer wrote:
> Sorry for the late reply... keeping up with xen-devel
> is getting tough!

Yes, I just occasionally skim...

> How does Linux do this on Power?  Xen/ia64 heavily
> leverages the equivalent Linux/ia64 code.  As you
> may know, Linux/ia64 scatters state all over
> memory and uses "unwind descriptors" so that it
> can recover all the state.  I'd imagine Power does
> something similar...

Linux has a per-kernel thread stack, so '_switch' saves the current (i.e. 
kernel, not original usermode) nonvolatiles to the previous task structure.

For Xen/PPC, we use a per-cpu stack, so we need to save the original (domain) 
nonvolatiles to the previous domain structure.

-- 
Hollis Blanchard
IBM Linux Technology Center

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

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