On Tue, Apr 4, 2017 at 6:27 AM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Tue, 4 Apr 2017 01:27:25 -0700
> Joel Fernandes <joelaf@xxxxxxxxxx> wrote:
>
>> Hi Steven,
>>
>> Just looking at code of the preemptirqsoff tracer, I wonder if it is
>> really working as expected.
>>
>> With the tracer enabled, start_critical_timing will be called only if
>> _both_ preemption and IRQs are turned off. Instead shouldn't this be
>> an OR condition (either preemption or IRQs are turned off)?
>
> What code are you looking at. From what I have:
Mainline.
>
> void start_critical_timings(void)
> {
> if (preempt_trace() || irq_trace())
> start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
> }
This is called from the idle path though.
>
> There's an OR statement.
Actually in trace_preempt_off, its an AND condition but the
irq_trace() is negated so it works correctly (too many double
negatives so I missed that, sorry!).
if (preempt_trace() && !irq_trace) ...
and likewise in trace_hardirqs_on, its:
if (!preempt_trace() && irq_trace())
So its all good :-)
Regards,
Joel
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