Re: NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule

From: Frederic Weisbecker
Date: Fri May 10 2013 - 05:26:45 EST


2013/5/10 Borislav Petkov <bp@xxxxxxxxx>:
> On Fri, May 10, 2013 at 02:29:31AM +0200, Frederic Weisbecker wrote:
>> @@ -616,8 +616,17 @@ static bool wake_up_full_nohz_cpu(int cpu)
>> {
>> if (tick_nohz_full_cpu(cpu)) {
>> if (cpu != smp_processor_id() ||
>> - tick_nohz_tick_stopped())
>> + tick_nohz_tick_stopped()) {
>> + if (!cpu_online(cpu)) {
>> + static int printed = 0;
>> + if (!printed) {
>> + printk("%d %d\n", cpu, smp_processor_id());
>> + dump_stack();
>> + printed = 1;
>
> You know about printk_once, right? We even have all the pr_<level>_once
> macros.
>
> :-)

But but that didn't fit as I also want the dump_stack(). May be we
want dump_stack_once().

In fact it would be nice to have DO_ONCE(something) and stuff whatever
we want inside.
All the printk_once() et. al could even be implemented using that.
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