Re: [RFC/T/D][PATCH 2/2] Linux/Guest cooperative unmapped page cache control

Balbir Singh
2010-06-17T06:04:28Z

* Avi Kivity <avi@redhat.com> [2010-06-16 14:39:02]:

> >We're talking about an environment which we're always trying to
> >optimize. Imagine that we're always trying to consolidate guests on to
> >smaller numbers of hosts. We're effectively in a state where we
> >_always_ want new guests.
>
> If this came at no cost to the guests, you'd be right. But at some
> point guest performance will be hit by this, so the advantage gained
> from freeing memory will be balanced by the disadvantage.
>
> Also, memory is not the only resource. At some point you become cpu
> bound; at that point freeing memory doesn't help and in fact may
> increase your cpu load.
>

We'll probably need control over other resources as well, but IMHO
memory is the most precious because it is non-renewable.

--
Three Cheers,
Balbir