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Date: Fri, 10 May 2013 11:26:39 +0200
Message-ID: <CAFTL4hxx_pHkJExnRks4hcOYGrJb8TCMRdCtt0UA-i3wsaWWcQ@mail.gmail.com>
Subject: Re: NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>, Tony Luck <tony.luck@intel.com>,
        linux-kernel@vger.kernel.org, x86@kernel.org
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2013/5/10 Borislav Petkov <bp@alien8.de>:
> 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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