On Mon, Sep 29, 2008 at 02:23:19PM -0500, James Chacon wrote: > > 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 >>> revivesa. >>> >>> 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 >>> points. >>> >>> 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... Yes, but NFS, Andrew's threading stuff, UVM, all of those are used constantly in -current, that won't be the case of SA... And please note I am just voicing what I think is a legitimate concern; that doesn't mean it is something impossible to live with. -- Quentin Garnier - cube%cubidou.net@localhost - cube%NetBSD.org@localhost "See the look on my face from staying too long in one place [...] every time the morning breaks I know I'm closer to falling" KT Tunstall, Saving My Face, Drastic Fantastic, 2007.
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