updated preempt-kernel

Penguins Rejoice: An updated preemptible kernel patch

Available now at

	http://tech9.net/rml/linux

for kernels 2.4.14-pre5, 2.4.13-ac5, 2.4.13, and 2.4.12.

First, an optimization: we redesigned the preemption counter code to not use atomic operators. This non-atomicity should result in a modest performance gain.

Second, we have a mailing list at [email protected] (see sf.net/projects/kpreempt) where we discuss technical issues and the occasional odd-bug is reported. Anyone with such interests is welcome.

Third, we have ARM support (in need of much testing) by Nico Pitre! You will need kernel 2.4.12-ac6, Russell's ARM patch available at

	ftp://ftp.arm.linux.org.uk/pub/armlinux/source/kernel-patches/v2.4/patch-2.4.12-ac6-rmk1.gz
the corresponding preempt-kernel patch available at 
	http://tech9.net/rml/linux/preempt-kernel-rml-2.4.12-ac6-1.patch
and finally the ARM-specific patch available at 
	ftp://ftp.arm.linux.org.uk/pub/linux/arm/people/nico/diff-2.4.12-ac6-rmk1-preempt.gz

Finally, the partial change log since the last public post:

20011030
- convert to non-atomic model:
o preempt_count is now an int
o memory validating is down via barrier()
o this removes many of the macros
o not using atomic ops should gain us some speed ...
- rename preempt_is_disable to preempt_is_disabled
- remove some extraneous ifdefs
- compile preempt_count into the task_struct regardless of whether CONFIG_PREEMPT is set. This way the offsets do not change depending on whether preemption is set.
- rediff all the patches off one codebase to insure no ambiguities, however I may introduce a typo since the trees do differ.
- update tty race fix

20011021
- add a Documentation/preempt-locking.txt
- merge fix to protect tty race on console close. this isn't our problem but preempt induces it. will try to merge into mainline.

Enjoy.

Robert Love