(Updated) Preemptible Kernel

This patch enables a preemptible kernel - now userspace programs can be preempted, even if in kernel land. This should result in greater system response.

Updated patches are available at:
http://tech9.net/rml/linux/patch-rml-2.4.9-ac12-preempt-kernel-1 and
http://tech9.net/rml/linux/patch-rml-2.4.10-pre11-preempt-kernel-1
for 2.4.9-ac12 and 2.4.10-pre11, respectively.

ChangeLog is at http://tech9.net/rml/linux/changelog-preempt

The Athlon-optimized problem is fixed and a final solution is merged.

We have had reported success with XFS, although a patch is required to compile, available at
http://tech9.net/rml/linux/other/patch-rml-2.4.10-pre10-xfs-preempt-fix-1

Finally, I have gotten great feedback from SMP users -- both in that "it works" and that benchmarks show an improvement. Thus, SMP and preemption together are no longer marked experimental.

The only outstanding issue is a possible issue with ReiserFS, although I am beginning to think this is attributed to VM muck and not ReiserFS. If you use ReiserFS, I would appreciate some feedback. (Note that the issue is _not_ fs corruption or anything of the ilk, just odd syslog messages and the such).

Please continue to supply feedback and relevant benchmarks. I really encourage "regular" users to try this out -- patch your kernel and enable CONFIG_PREEMPT. I am not an audio guy, trust me -- this is worth it for any desktop.

Robert M. Love
rml at ufl.edu
rml at tech9.net

2.4.10-pre12-preempt patch is available at
http://tech9.net/rml/linux/patch-rml-2.4.10-pre12-preempt-kernel-1

Also, the XFS fix has been committed to CVS. So subsequent CVS dumps or releases will not need the extra patch.

Robert M. Love
rml at ufl.edu
rml at tech9.net