On Wed, 27 Oct 2021 00:06:17 +0200
Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> wrote:
> static int osnoise_tracer_init(struct trace_array *tr)
> {
> -
> - /* Only allow one instance to enable this */
> - if (osnoise_has_registered_instances())
> + /*
> + * Only allow osnoise tracer if timerlat tracer is not running
> + * already.
> + */
> + if (osnoise_data.timerlat_tracer)
> return -EBUSY;
>
This fails to build when timerlat is not enabled:
/work/git/linux-trace.git/kernel/trace/trace_osnoise.c: In function ‘osnoise_tracer_init’:
/work/git/linux-trace.git/kernel/trace/trace_osnoise.c:2161:18: error: ‘struct osnoise_data’ has no member named ‘timerlat_tracer’
2161 | if (osnoise_data.timerlat_tracer)
| ^
make[3]: *** [/work/git/linux-trace.git/scripts/Makefile.build:277: kernel/trace/trace_osnoise.o] Error 1
Also, I hate all the #ifdef muckery in this file. What you need is:
static struct osnoise_data {
u64 sample_period; /* total sampling period */
u64 sample_runtime; /* active sampling portion of period */
u64 stop_tracing; /* stop trace in the internal operation (loop/irq) */
u64 stop_tracing_total; /* stop trace in the final operation (report/thread) */
#ifdef CONFIG_TIMERLAT_TRACER
u64 timerlat_period; /* timerlat period */
u64 print_stack; /* print IRQ stack if total > */
int timerlat_tracer; /* timerlat tracer */
#endif
bool tainted; /* infor users and developers about a problem */
} osnoise_data = {
.sample_period = DEFAULT_SAMPLE_PERIOD,
.sample_runtime = DEFAULT_SAMPLE_RUNTIME,
.stop_tracing = 0,
.stop_tracing_total = 0,
#ifdef CONFIG_TIMERLAT_TRACER
.print_stack = 0,
.timerlat_period = DEFAULT_TIMERLAT_PERIOD,
.timerlat_tracer = 0,
#endif
};
#ifdef CONFIG_TIMERLAT_TRACER
static bool timerlat_enbabled()
{
return osnoise_data.timerlat_tracer;
}
static void timerlat_softirq_exit(void)
{
struct timerlat_variables *tlat_var;
tlat_var = this_cpu_tmr_var();
if (!tlat_var->tracing_thread) {
osn_var->softirq.arrival_time = 0;
osn_var->softirq.delta_start = 0;
}
}
#else
static inline bool timerlat_enbabled()
{
return false;
}
static void timerlat_softirq_exit(void) { }
#endif
Then in places like trace_softirq_exit_callback() you can have:
if (unlikely(timerlat_enabled())
timerlat_softirq_exit();
And this will help in making mistakes like you did with the compile
failure.
So there should be no #ifdef in any functions (it's fine to wrap
functions).
-- Steve
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