Re: [Xen-devel] [PATCH V5 28/32] libxl: store up-to-date domain configuration as we create domain

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Sun, 2014-06-01 at 20:02 +0100, Wei Liu wrote:
> On Tue, May 20, 2014 at 03:12:18PM +0100, Ian Campbell wrote:
> > On Tue, 2014-05-13 at 22:54 +0100, Wei Liu wrote:
> > > This patch utilizes "libxl-json" format and helper functions introduced
> > > in previous patch to store up-to-do domain configuration when creating a
> > > domain.
> > > 
> > > Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> > 
> > This seems to end up saving the domain config 2 or even 3 times. I think
> > we need an explanation as to why that is.
> > 
> 
> Twice (see below).
> 
> > Also we need to know what the invariants are, what must (not) change
> > either before or after each sequencing point, what must be in each
> > update etc.
> > 
> 
> The first save is the vanilla copy, that's what the user provides.
> 
> Then udpate_domain_config is called to pull in everything that may get
> changed by libxl to the vanilla copy. What's pulled in is documented in
> update_domain_config.
> 
> The second save saves the updated version.
> 
> > Can you not save the raw version at the start (before anything has
> > touched it) and then do the domid, uuid, mac, vtpm etc all at the end in
> > domcreate_complete? (Don't you do the uuid twice? The comments mention
> > it twice)
> >  
> 
> I don't follow. I think this is what being done at the moment. The
> vanilla domain configuration is saved at the beginning of domain
> creation then updated when domain creation completes. It's exactly what
> you suggested.
> 
> Re UUID, no. Domain UUID and UUID for devices are different things.

I think perhaps that's what I got confused about and thought there were
more saves than I expected.

Ian.


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel