Re: [Xen-devel] Re: [XEN] using shmfs for swapspace

[Luke Kenneth Casson Leighton <lkcl@lkcl.net>]

On Tue, Jan 04, 2005 at 09:05:13AM -0500, Rik van Riel wrote:
> On Tue, 4 Jan 2005, Mark Williamson wrote:
> 
> >>for doing opportunistic page recycling ("I dont need this page but when
> >>I ask for it back please tell me if you trashed the content")
> >
> >We've talked about doing this but AFAIK nobody has gotten round to it 
> >yet because there hasn't been a pressing need (IIRC, it was on the todo 
> >list when Xen 1.0 came out).
> >
> >IMHO, it doesn't look terribly difficult but would require (hopefully 
> >small) modifications to the architecture independent code, plus a little 
> >bit of support code in Xen.
> 
> The architecture independant changes are fine, since
> they're also useful for S390(x), PPC64 and UML...
> 
> >I'd quite like to look at this one fine day but I suspect there are more 
> >useful things I should do first...
> 
> I wonder if the same effect could be achieved by just
> measuring the VM pressure inside the guests and
> ballooning the guests as required, letting them grow
> and shrink with their workloads.
 
 mem = 64M-128M
 target = 64M

 "if needed, grow me to 128mb but if not, whittle down to 64".

 mem=64M-128
 target=128M

 "if you absolutely have to, steal some of my memory, but don't nick
 any more than 64M".

 i'm probably going to have to "manually" implement something like this.

 l.