Re: v2.6.21-rt2

[Daniel Walker <dwalker@mvista.com>]

On Thu, 2007-05-17 at 00:04 +0200, Ingo Molnar wrote:
> * Daniel Walker <dwalker@mvista.com> wrote:
> 
> > I don't know. irqs_off_preempt_count() could get used someplace else, 
> > where you would want to flip the preempt_count() check .. It seems 
> > sane to combine your patch with mine ..
> > 
> > irqs_off_preempt_count() (!__get_cpu_var(trace_cpu_idle) && 
> > preempt_count())
> > 
> > You can't call __get_cpu_var() without the a positive preempt_count(), 
> > so the check seems backwards regardless of the other factors ..
> 
> yeah. The whole trace_preempt_enter_idle() thing looks a bit suspect. 
> Why cannot those architectures simply disable/enable preemption and get 
> the same effect? It's not like we ever want to allow the preemption of 
> the idle task.

They disable interrupts it looks like (i386, and x86_64), around the
same area where those trace_preempt_enter_idle calls are placed .. I'm
not up on the details of Steve's fix .. There's also a
preempt_disable/preempt_enable ..

I'm not up on the details of Steve's fix , but stuff looks a little
odd ..

Daniel