RE: [Xen-devel] Code size vs. linux source code compatibility in the hypervisor

["Neugebauer, Rolf" <rolf.neugebauer@xxxxxxxxx>]

As part of the next release we plan to move most of the platform init
code into dom0. This includes PCI & IO-APIC setup etc for which we
currently need the ACPI parts. So hopefully most of the unnecessary code
you identified and probably more will disappear.
rolf

> -----Original Message-----
> From: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx [mailto:xen-devel-
> admin@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of Tobias Hunger
> Sent: 29 January 2005 11:32
> To: xen-devel@xxxxxxxxxxxxxxxxxxxxx
> Subject: [Xen-devel] Code size vs. linux source code compatibility in
the
> hypervisor
> 
> Hello there!
> 
> I recently spend some time trying to better understand the hypervisor
part
> of
> xen and decided to dive into the code in the xen subdirectory. David
A.
> Wheeler's 'SLOCCount' reports about 53k lines of C code there.
> 
> My first impression was that much of the code is in fact unused by Xen
and
> mostly there, because it was salvaged from the Linux kernel. To aid my
> understanding of Xen I started to trim down on macros and functions. I
was
> surprised to be able to actually remove about 8k lines of code and
1.5k
> macro
> definitions from the ACPI part! Xen still builds and runs for me:-)
Since
> the
> compiler will optimize out unused code this reduction is not reflected
in
> the
> compiled size of the hypervisor (mine is identical in size to the one
> build
> from yesterdays unstable tarball).
> 
> My question is: What is the stance of the core team on the issue of
code
> size
> vs. linux source code compatibility? The less code the easier it is
for
> others to get into the project, while keeping the complete linux code
> around
> might make moving new code over to xen easier. Are you interested in
> patches
> to remove unused code? Mine currently removes almost all the header
files
> in
> include/acpi...
> 
> What do you think about #if 0 in code? I personally hate that: There
is
> version tracking, so there is no reason to keep old code visible that
way.
> What about all those "#ifdef CONFIG_FOO" lines from the linux kernel?
> Currently xen is rather fixed in the configuration it supports and
uses.
> Is
> that a feature of xen (then those #ifdefs can go IMHO) or supposed to
> change
> over time?
> 
> As you might have noticed I have not used C too much for the last
couple
> of
> years and never was a fan of cpp in the first place:-) This code
rewriting
> all over the place keeps knocking me out of the flow of understanding
what
> is
> happening.
> 
> --
> Gruss,
> Tobias
> 
> ------------------------------------------------------------
> Tobias Hunger           The box said: 'Windows 95 or better'
> tobias@xxxxxxxxxxx                     So I installed Linux.
> ------------------------------------------------------------


-------------------------------------------------------
This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting
Tool for open source databases. Create drag-&-drop reports. Save time
by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc.
Download a FREE copy at http://www.intelliview.com/go/osdn_nl
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel