Re: [2.4.17/18pre] VM and swap - it's really unusable

Daniel Phillips
2002-01-14T16:55:22Z

On January 14, 2002 12:33 am, J Sloan wrote:
> Dieter Nützel wrote:
> >You told me that TUX show some problems with preempt before. What
> >problems? Are they TUX specific?
>
> On a kernel with both tux and preempt, upon
> access to the tux webserver the kernel oopses
> and tux dies...

Ah yes, I suppose this is because TUX uses per-cpu data as a replacement
for spinlocks. Patches that use per-cpu shared data have to be
preempt-aware. Ingo didn't know this when he wrote TUX since preempt didn't
exist at that time and didn't even appear to be on the horizon. He's
certainly aware of it now.

> OTOH the low latency patch plays quite well
> with tux. As said, I have no anti-preempt agenda,
> I just need for whatever solution I use to work,
> and not crash programs and services we use.

Right, and of course that requires testing - sometimes a lot of it. This one
is a 'duh' that escaped notice. temporarily. It probably would have been
caught sooner if we'd started serious testing/discussion sooner.

--
Daniel