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Re: kFreeBSD for Xen (and related lintian stuff)

Hi Steven,

El 2 d’abril de 2012 23:56, Steven Chamberlain <steven@pyro.eu.org> ha escrit:
> performance would be better by rebuilding with
> extra options from upstream's XENHVM configurations;  these add drivers
> for optional paravirtualised disk/net devices, and Xen PCI passthrough,
> and also set the NO_ADAPTIVE_* options as an optimisation.

Any idea why these are not in GENERIC?  What are the drawbacks?

I think this would be better discussed with upstream.

> Unlike for the other kFreeBSD flavours, the xen.config includes
> upstream's own XEN config file rather than being a copy of it.

Please take kfreebsd-10 as reference, they all use includes there.

>  In the
> included file is 'DEBUG=-g', which results in a kernel.symbols file
> being generated.  Lintian flags the file as an
> 'unstripped-binary-or-object' and also (presumably a false detection) as
> 'statically-linked-binary'.
> A -DWITHOUT_KERNEL_SYMBOLS was added to both kfreebsd-8 and kfreebsd-9.
> possibly as a workaround for this.

KERNEL_SYMBOLS is the knob intended for user to select this.  Note
that DEBUG can be set in many places, config file is not the only one.

> (actually, I think setting WITHOUT_KERNEL_SYMBOLS to some
> value other than 'no' will cause the issue to recur...).

This is not how make knobs work.  See:


> The upstream XEN config file contains MODULES_OVERRIDE="", causing no
> modules to be built at all for the "xen" flavour.  I don't see a reason
> to disable all modules like that, because some would be still useful.

Does module loading work on XEN flavor?  On PAE it was disabled
because it doesn't.

Again I think this would be better discussed with upstream.

> The "xen" flavour of both kernel series has WITNESS and WITNESS_SKIPSPIN
> options enabled which I think are supposed to be turned off for release
> builds.

Are you sure?  What about:

# disable extra checks enabled in upstream XEN config
nooption        INVARIANTS              # Enable calls of extra sanity checking
nooption        INVARIANT_SUPPORT       # Extra sanity checks of
internal structures, required by INVARIANTS
nooption        WITNESS                 # Enable checks to detect
deadlocks and cycles
nooption        WITNESS_SKIPSPIN        # Don't run witness on
spinlocks for speed

> Once I have my Xen host system (hopefully tomorrow) I should be able to
> properly test and provide diffs to fix some of the above issues.

Thanks for looking into this!

Robert Millan

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