Premptible kernel

[Felipe Alfaro Solana]

On Sun, 2004-02-22 at 23:36, Peter Backlund wrote:
> If I remember correctly, preemption isn't enabled in the kernel due to 
> problems with SMP. Is that still true? If so, would it be possible to 
> build the UP kernel with preemption enabled?

I don't think preempt is disabled due to problems with SMP. IIRC
preemption basically represents the efforts of the kernel hackers to
improve kernel reentrancy and remove the Big Kernel Lock to increase
scalability on SMP systems. I think preemption is disabled since there
are some drivers which do not work well enough when used with preemtion
enabled. I have also heard there is some hard-to-reproduce bug which is
triggered more easily when preemp is enabled.

However, you can compile the kernel yourself and enable preemption on UP
systems In fact, I've been running preemptible kernels since 2.5.48 or
so and they have always worked neatly for me.