Xen devel - May 2006 - RE: [PATCH] Make "xm mem-set" be lower bound ondomX-min-mem

Yes, trying to balloon a domain to less than 2% of its initial memory
allocation causes things to go haywire.

 

http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=651

 

Aravindh

 

________________________________

From: xen-devel-bounces@lists.xensource.com
[mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of Gareth S
Bestor
Sent: Saturday, May 20, 2006 5:28 PM
To: Keir Fraser
Cc: xen-devel@lists.xensource.com
Subject: Re: [Xen-devel] [PATCH] Make "xm mem-set" be lower bound
ondomX-min-mem

 
>...shrinking to <2% of original allocation is a very bad idea
An absolute limit might be easier to handle - and expose to users - than
a relative one, especially up-front in CIM where it exposes min/max
limits on resource allocations. Or is it really <2% of whatever the
original memory allocation is when things go to kabluwey... ?

BTW - at the moment we are exposing a 16MB minimum DomU memory size thru
our CIM providers resource allocation defaults, although this is more a
hint than anything actually enforced; the mgmt client can still pass in
whatever value they like and we (CIM) will blindly pass it along to xm
create ...

- Gareth

Dr. Gareth S. Bestor
IBM Linux Technology Center
M/S DES2-01
15300 SW Koll Parkway, Beaverton, OR 97006
503-578-3186, T/L 775-3186, Fax 503-578-3186 

 Keir Fraser <Keir.Fraser@cl.cam.ac.uk>



Keir Fraser <Keir.Fraser@cl.cam.ac.uk> 

05/20/06 01:26 AM

 

To

 
Gareth S Bestor/Beaverton/IBM@IBMUS



cc


xen-devel@lists.xensource.com



Subject


Re: [Xen-devel] [PATCH] Make "xm mem-set" be lower bound on
domX-min-mem

 





>  Unless there is an known *architectural* limit in Xen on the lower 
> bound of the memory for a guest DomU, then I agree - xend
>  shouldn''t impose an arbitrary one simply to act as ''hard
hint'' to
> prevent stupid users from doing stupid things
>  (give ''em all the rope they want I say! :-) Care-and-feeding of
naive
> users is best left to tools higher up the mgmt stack (IMO).
I agree with this. I''m also not sure about putting a lower bound in the
balloon driver, but at least there we know that shrinking to <2% of 
original allocation is a very bad idea with very high probability.

 -- Keir








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