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Re: Status of revivesa

On Sep 29, 2008, at 2:16 PM, Quentin Garnier wrote:

On Mon, Sep 29, 2008 at 11:43:17AM -0700, Bill Stouder-Studenmund wrote:
On Mon, Sep 29, 2008 at 10:39:18AM -0400, Christos Zoulas wrote:
What still isn't clear to me is what exactly the negatives are of

The biggest one I'm hearing is that a number of people HATE it. Flat out HATE it. I'm not really sure what to do with this one, since it's hard to
understand. It's an emotion, and we usually try to stick to technical

The SA that's on revivesa is a kernel option. If you don't want it, don't enable it. If we find a catastrophic flaw in it (or security issue) late in the 5.0 release proces, we turn it off in the default kernels and tell
people to only re-enable it with caution.

SA is not becoming, nor do I ever envision it becoming, the default
threading out-of-the-box for NetBSD. Some sites may eventually prefer it, but that's a specialized situation. And something an admin would have to
explicitly select.

The main issue with SA is maintainability.  We failed to maintain it
once, how likely are we to succeed now?  I have a lot of respect for
your work on that, but I don't really see anyone maintaining it if for
some reason you can't really do it anymore.

Supposing it will be enabled by default, it won't be at risk of simply
rotting;  but merely compiling doesn't equal working, especially for a
piece of code that is affected by many different areas of the kernel,
including MD ones. And once 5.0 is out, it will hardly be tested until
6.0 is ready for release because you don't upgrade a system from a
release to current the same way you upgrade a system from one release to
another.  The GDT issue is a perfect example of that.

The same issue about maintenance can be made of a lot of code in the system. Beyond Andrew just how many people are diving in and maintaining the replacement thread code? It's always a small number...


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