[libvirt] [PATCH 1/3] add percentage limit parse and define support for RAM filesystems

[Chen Hanxiao]

> -----Original Message-----
> From: Daniel P. Berrange [mailto:berrange at redhat.com]
> Sent: Thursday, December 05, 2013 9:17 PM
> > >
> > > I just don't see this as a compelling feature. I think it is more important
> > > to have a single canonical representation of memory allocation. User
> > > convenience is something for higher level tools to worry about.
> >
> > But do higher level tools already have a way to query libvirt what the
> > current host's available ram is, in order to determine percentages
> > itself?  We can't really migrate online LXC guests, but for an offline
> > guest setup, copying XML from one host with small memory to another host
> > with large memory, and still having the guest have a fixed percentage of
> > the host resources (more memory assigned to the guest on the larger
> > host), seems like a reasonable desire; to achieve that, the management
> > tool needs to be able to either request percentages (no change to the
> > guest xml being copied) or know the host resource limits (and rewrite
> > the xml rather than merely copy it).
> 
> We do have APIs for querying host RAM, but if we wanted this, which I
> don't think we do, then tmpfs RAM % would want to be relative to guest
> RAM allocation not host RAM. It doesn't make sense to have guest XML
> whose semantics differ according to the host environment - they should
> be self-contained.

If we could set tmpfs RAM % according to guest memory
allocation(domain/memory section),
does that make sense?

> 
> Daniel
> --
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