* Arne Jansen <lists@xxxxxxxxxxxxxx> wrote:
> On 06.06.2011 19:11, Ingo Molnar wrote:
> >
> >* Peter Zijlstra<peterz@xxxxxxxxxxxxx> wrote:
>
> >
> >>+void printk_tick(void)
> >>+{
> >>+ if (!__this_cpu_read(printk_pending))
> >>+ return;
> >>+
> >>+ /*
> >>+ * Try to acquire and then immediately release the
> >>+ * console semaphore. The release will do all the
> >>+ * actual magic (print out buffers, wake up klogd,
> >>+ * etc).
> >>+ */
> >>+ if (console_trylock_for_printk(smp_processor_id())) {
> >>+ console_unlock();
> >>+ __this_cpu_write(printk_pending, 0);
> >>+ }
> >>+}
> >
> >Arne does this fix the hang you are seeing?
>
> What do you want me to test? just replace printk_tick with the
> above version? If I do that, the machine doesn't even boot up any
> more.
Yeah.
So i think we want two patches:
- The first one that minimally removes the lockdep_off()/on() dance
and fixes the regression: the patch that i sent earlier today.
I *think* that should fix the crash.
3.0 material.
- The second one that moves console_sem wakeups to the jiffies tick.
It does not push the acquiring and the console->write() calls to
jiffies context, only delays the wakeup.
3.1 material.
Thanks,
Ingo
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