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

[Xen-devel] balloon question

To: <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] balloon question
From: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Date: Thu, 08 Jun 2006 15:51:59 +0200
Delivery-date: Thu, 08 Jun 2006 08:59:37 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Running with Xen option dom0_mem=6G and kernel option mem=8G, I would have 
expected that I would see the system with a
2G balloon right after boot. However, the balloon is empty. Briefly looking at 
this, it would seem to me that, with all
pages being reserved when the system starts and only the populated ones getting 
the reserved status cleared in
__free_pages_bootmem(), the condition to put pages into the balloon in 
balloon_init() is inverted.

Also, dying in xen_destroy_contiguous_region() (and similarly in the failure 
recovery code in
xen_create_contiguous_region()) if the space just unmapped can't be 
re-populated seems overly harsh (we're having a case
where this actually happens); wouldn't it make sense to make this fatal only 
when the page can't be replaced by a free
one (allocated inside the domain, with the page stolen for this then simply 
pushed into the balloon, similar to
balloon_alloc_empty_page_range() except without freeing the memory to Xen)?

Thanks for clarification,
Jan

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

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