Re: [PATCH] scheduler: fix x86 regression in native_sched_clock

From: Andrew Morton
Date: Fri Dec 07 2007 - 06:11:46 EST


On Fri, 7 Dec 2007 11:40:13 +0100 Ingo Molnar <mingo@xxxxxxx> wrote:

>
> * Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> > > - t = printk_clock();
> > > + t = cpu_clock(printk_cpu);
> > > nanosec_rem = do_div(t, 1000000000);
> > > tlen = sprintf(tbuf,
> > > "<%c>[%5lu.%06lu] ",
> >
> > A bit risky - it's quite an expansion of code which no longer can call
> > printk.
> >
> > You might want to take that WARN_ON out of __update_rq_clock() ;)
>
> hm, dont we already detect printk recursions and turn them into a silent
> return instead of a hang/crash?
>

We'll pop the locks and will proceed to do the nested printk. So
__update_rq_clock() will need rather a lot of stack ;)
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