vkernel & GSoC, some questions
Kris Kennaway
kris at FreeBSD.org
Mon Mar 17 20:59:32 UTC 2008
Matthew Dillon wrote:
> :I don't think there's an issue that needs solving, GCC has -nostdlib and
> :-fno-builtin for precisely this reason.
>
> You are missing the point entirely. The point is to allow the vkernel
> to use libc, aka allow it to be compiled, linked, and run as a normal
> user process. What is your rationale for trying to bypass libc? Why
> is it so important to you that the kernel retain all those conflicting
> symbols when it takes literally just an hour of work to fix all the
> conflicts?
If your goal is to link vkernels with libc then by definition you are
forced to resolve the namespace conflicts, but I don't see this as a
necessary goal. A minimal standalone libkernel would do the same thing
without requiring global changes to the kernel namespace, which would
likely cause a lot of downstream angst for users of FreeBSD kernel code,
providers of third party modules, etc. It seems pretty hard to justify
that level of disruption.
> :Anyway, I agree that this is the least of someone's worries during a
> :hypothetical port of the dragonfly vkernel code. Just so everyone is
> :clear, the scope of such an effort would not be "port the code", it
> :would be "port the code and also finish it".
> :
> :Kris
>
> Jeeze, you make it sound like it is some incomplete mess when it is
> far, far from that. The vkernel is complete, the APIs are complete.
> It isn't finished in the sense that certain aspects of it, primarily
> the 'disk' emulation, is not very well optimized, but you are doing
> the work an extreme disservice by belittling it with undeserving
> labels.
What is the undeserving label? You agree that the code is not finished.
In your previous emails you yourself gave a long discussion of changes
that would need to be made to bring reasonable performance to various
aspects of the vkernel code. I am not discouraging anyone from
contributing to that work either in the context of the FreeBSD project
or the Dragonfly project; on the contrary we are both pointing out that
there is work that needs to be done by someone.
Kris
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