[PATCH] sched: improve preempt debugging

From: Ingo Molnar
Date: Mon Jan 26 2009 - 10:22:35 EST

* Alexey Zaytsev <alexey.zaytsev@xxxxxxxxx> wrote:

> From: Alexey Zaytsev <alexey.zaytsev@xxxxxxxxx>
> Subject: [PATCH] Set the initial softirq preempt count to SOFTIRQ_OFFSET
> Does not changes the preemption semantics, as the
> softirq's obviously can't be preempted, but fixes
> a spurious warning in sub_preempt_count, which
> happens when the preempt count is returned to
> zero, and the interrupted thread is holding the
> BKL.
> Signed-off-by: Alexey Zaytsev <alexey.zaytsev@xxxxxxxxx>

applied to tip/sched/urgent, thanks Alexey.

I also re-added Nick's original patch on top of that (see it below) - this
way we'll see whether it's all sorted out for good.