Messages in this thread |  | | | Date | Fri, 5 Dec 2008 00:03:20 +0100 | | From | "Frédéric Weisbecker" <> | | Subject | Re: [PATCH 1/3] tracing/ftrace: don't insert TRACE_PRINT during selftests |
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2008/12/4 Steven Rostedt <rostedt@goodmis.org>: > The comment style should be: > > /* > * comment > * comment > * comment > */
Sorry, will fix it.
> >> +static atomic_t tracing_selftest_running = ATOMIC_INIT(0); > > Do we need that is atomic? Also, it needs to be __read_mostly.
I thought it should be atomic to be sure the value is synchronized on smp when read. But actually that should have been more likely an int with smp_wb after writing it.
>> + >> /* For tracers that don't implement custom flags */ >> static struct tracer_opt dummy_tracer_opt[] = { >> { } >> @@ -589,6 +597,8 @@ int register_tracer(struct tracer *type) >> struct tracer *saved_tracer = current_trace; >> struct trace_array *tr = &global_trace; >> int i; >> + >> + atomic_set(&tracing_selftest_running, 1); > > Enable this in the mutex lock, and we could make it a normal int. >
But ftrace_printk can be called from interrupt context. I think we can loose some TRACE_PRINT entries at the selftests time since the tracer are not enabled by the user at this time, except the boot tracer...
>> /* >> * Run a selftest on this tracer. >> * Here we reset the trace buffer, and set the current >> @@ -603,6 +613,7 @@ int register_tracer(struct tracer *type) >> /* the test is responsible for initializing and enabling */ >> pr_info("Testing tracer %s: ", type->name); >> ret = type->selftest(type, tr); >> + atomic_set(&tracing_selftest_running, 0); >> /* the test is responsible for resetting too */ >> current_trace = saved_tracer; >> if (ret) { >> @@ -3594,7 +3605,7 @@ int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args) >> unsigned long flags, irq_flags; >> int cpu, len = 0, size, pc; >> >> - if (tracing_disabled) >> + if (tracing_disabled || atomic_read(&tracing_selftest_running)) >> return 0; >> >> pc = preempt_count(); >> -- > > -- Steve > >
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