Messages in this thread | | | Date | Wed, 27 Oct 2021 22:50:51 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH V6 06/20] trace/osnoise: Allow multiple instances of the same tracer |
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On Wed, 27 Oct 2021 00:06:17 +0200 Daniel Bristot de Oliveira <bristot@kernel.org> 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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