Re: [patch] Real-Time Preemption, -RT-2.6.12-rc4-V0.7.47-06

Ingo Molnar
2005-06-01T09:20:28Z

* Michal Schmidt <xschmi00@stud.feec.vutbr.cz> wrote:

> Hi Ingo,
>
> I'm now running -RT-2.6.12-rc4-V0.7.47-08 on amd64. I use cpufreq, but
> with the RT kernel it triggers "Kernel BUG at "kernel/latency.c":1295"
> (the check for preempt_count underflow).
>
> I'm attaching a patch which changes a semaphore in cpufreq into a
> completion. With this patch, my system runs OK even with cpufreqd.

btw., could you please submit this upstream too, so that it doesnt get
lost? Semaphore->completion conversions are desirable upstream for cases
where the semaphore was in reality not used for mutual exclusion but for
completion purposes. (in which case real completions are both more
readable and slightly faster)

Ingo