Hello,

For hackers,
The following patch makes the kernel preemptable.
It is against 2.4.0-prerelease on for i386 only.
It should work for UP and SMP even though I
didn't validate it on SMP.
Comments are welcome.

NOTES: since the lock implementation is modified,
you need obviously to re-compile all your modules.
I introduced a dependency between spinlock.h and sched.h
and this has some bad side effects: Some files will
generate warnings during the compilation complaining
that disable_preempt()/enable_preempt() are not defined.
The warnings should be harmless but I was too lazy to
fix all of them. If the compilation fails because of
that, there is big chance to fix things by including
sched.h in the cfile.

Ludo.