Re: top stack (l)users for 2.5.69

Ingo Oeser
2003-05-08T16:54:51Z

On Wed, May 07, 2003 at 09:01:44AM -0700, William Lee Irwin III wrote:
> Pure per-cpu stacks would require the interrupt model of programming to
> be used, which is a design decision deep enough it's debatable whether
> it's feasible to do conversions to or from at all, never mind desirable.
> Basically every entry point into the kernel is treated as an interrupt,
> and nothing can ever sleep or be scheduled in the kernel, but rather
> only register callbacks to be run when the event waited for occurs.
> Scheduling only happens as a decision of which userspace task to resume
> when returning from the kernel to userspace, though one could envision
> a priority queue discipline for processing the registered callbacks.

To illustrate that: It's basically a difference like between
fork() and spawn(). Threads (of control) are completely decoupled
und re-coupled only by the event/callback mechanism.

This is introducing exactly the mechanisms Linus didn't like when
he decided, that he doesn't want a micro kernel architecture.

So it is not going to happen RSN.

Regards

Ingo Oeser
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