[XenPPC] Re: [Xen-devel] architecture-specific stuff in xend
On Wed, Aug 09, 2006 at 10:07:12AM -0500, Hollis Blanchard wrote:
> On Wed, 2006-08-09 at 10:28 +0100, Ewan Mellor wrote:
> > On Tue, Aug 08, 2006 at 04:59:53PM +0100, John Levon wrote:
> >
> > > On Tue, Aug 08, 2006 at 10:34:25AM -0500, Hollis Blanchard wrote:
> > >
> > > > I'm not sure how/where to instantiate the arch object though.
> > >
> > > Presumably you could do the instance() singleton trick?
> >
> > This being Python, you don't actually need singletons -- the containing
> > module
> > is a singleton in its own right. You can just write
> >
> > Platform.py:
> >
> > import os
> >
> > if os.uname()[4] in ('ia64', 'ppc64'):
> > def init_reservation(mem_kb):
> > return something_else(mem_kb)
> >
> > else:
> > def init_reservation(mem_kb):
> > return mem_kb
> >
> > and then
> >
> > import Platform
> > Platform.init_reservation(100)
> >
> > will do the right thing.
>
> Ewan, does this mean you think the proposal is going in the right
> direction and you're waiting for a patch?
Yes, your proposal sounds fine to me.
Ewan.
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[XenPPC] Re: [Xen-devel] architecture-specific stuff in xend
On Wed, 2006-08-09 at 10:28 +0100, Ewan Mellor wrote:
> On Tue, Aug 08, 2006 at 04:59:53PM +0100, John Levon wrote:
>
> > On Tue, Aug 08, 2006 at 10:34:25AM -0500, Hollis Blanchard wrote:
> >
> > > I'm not sure how/where to instantiate the arch object though.
> >
> > Presumably you could do the instance() singleton trick?
>
> This being Python, you don't actually need singletons -- the containing module
> is a singleton in its own right. You can just write
>
> Platform.py:
>
> import os
>
> if os.uname()[4] in ('ia64', 'ppc64'):
> def init_reservation(mem_kb):
> return something_else(mem_kb)
>
> else:
> def init_reservation(mem_kb):
> return mem_kb
>
> and then
>
> import Platform
> Platform.init_reservation(100)
>
> will do the right thing.
Ewan, does this mean you think the proposal is going in the right
direction and you're waiting for a patch?
--
Hollis Blanchard
IBM Linux Technology Center
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[XenPPC] Re: [Xen-devel] architecture-specific stuff in xend
On Tue, Aug 08, 2006 at 04:59:53PM +0100, John Levon wrote:
> On Tue, Aug 08, 2006 at 10:34:25AM -0500, Hollis Blanchard wrote:
>
> > Rather than having these inline tests everywhere ("if os.uname()[4] in
> > ('ia64', 'ppc64'):"), would it make more sense to have some sort of
> > "architecture" object, and do things like:
>
> It'd be good if it were slightly more general and covered other system
> stuff too (namely OS). On Solaris some of the Xen binaries/scripts live
> in different locations in order to meet our file system requirements.
>
> > I'm not sure how/where to instantiate the arch object though.
>
> Presumably you could do the instance() singleton trick?
This being Python, you don't actually need singletons -- the containing module
is a singleton in its own right. You can just write
Platform.py:
import os
if os.uname()[4] in ('ia64', 'ppc64'):
def init_reservation(mem_kb):
return something_else(mem_kb)
else:
def init_reservation(mem_kb):
return mem_kb
and then
import Platform
Platform.init_reservation(100)
will do the right thing.
Ewan.
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[XenPPC] Re: [Xen-devel] architecture-specific stuff in xend
On Tue, Aug 08, 2006 at 11:15:18AM -0500, Hollis Blanchard wrote: > > On Solaris some of the Xen binaries/scripts live > > in different locations in order to meet our file system requirements. > > Does that impact code under tools/python/xen much? Very little, but it does affect the location of the network scripts, for example. > > Presumably you could do the instance() singleton trick? > > Not sure what you mean. See XendRoot.py's instance(). > Actually, you bring up a good point: since we have no state (at least > not in the examples I'm thinking of), we really don't want/need a class; > a module would do just fine. So we could have separate files/modules > with just plain functions: > > platform/ia64.py: > def init_reservation(mem_kb): > return something > > platform/platform.py: > import xen.xend.platform.ia64 as platform We'd still need something to import the right bits... regards john ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
[XenPPC] Re: [Xen-devel] architecture-specific stuff in xend
On Tue, 2006-08-08 at 16:59 +0100, John Levon wrote:
> On Tue, Aug 08, 2006 at 10:34:25AM -0500, Hollis Blanchard wrote:
>
> > Rather than having these inline tests everywhere ("if os.uname()[4] in
> > ('ia64', 'ppc64'):"), would it make more sense to have some sort of
> > "architecture" object, and do things like:
>
> It'd be good if it were slightly more general and covered other system
> stuff too (namely OS).
Sure, we could make it "class Platform" and have it represent an
architecture/OS pair.
> On Solaris some of the Xen binaries/scripts live
> in different locations in order to meet our file system requirements.
Does that impact code under tools/python/xen much?
> > I'm not sure how/where to instantiate the arch object though.
>
> Presumably you could do the instance() singleton trick?
Not sure what you mean.
Actually, you bring up a good point: since we have no state (at least
not in the examples I'm thinking of), we really don't want/need a class;
a module would do just fine. So we could have separate files/modules
with just plain functions:
platform/ia64.py:
def init_reservation(mem_kb):
return something
platform/platform.py:
import xen.xend.platform.ia64 as platform
... or something. Like I said, I really don't know modules, but as long
as we don't have any arch-specific state we need to save, I'm pretty
sure modules are the right solution to this problem.
--
Hollis Blanchard
IBM Linux Technology Center
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[XenPPC] Re: [Xen-devel] architecture-specific stuff in xend
On Tue, Aug 08, 2006 at 10:34:25AM -0500, Hollis Blanchard wrote:
> Rather than having these inline tests everywhere ("if os.uname()[4] in
> ('ia64', 'ppc64'):"), would it make more sense to have some sort of
> "architecture" object, and do things like:
It'd be good if it were slightly more general and covered other system
stuff too (namely OS). On Solaris some of the Xen binaries/scripts live
in different locations in order to meet our file system requirements.
> I'm not sure how/where to instantiate the arch object though.
Presumably you could do the instance() singleton trick?
regards
john
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