1c80025a49
Impact: extend the ->init() method with the ability to fail This bring a way to know if the initialization of a tracer successed. A tracer must return 0 on success and a traditional error (ie: -ENOMEM) if it fails. If a tracer fails to init, it is free to print a detailed warn. The tracing api will not and switch to a new tracer will just return the error from the init callback. Note: this will be used for the return tracer. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
53 lines
848 B
C
53 lines
848 B
C
/*
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* nop tracer
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*
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* Copyright (C) 2008 Steven Noonan <steven@uplinklabs.net>
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*
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/debugfs.h>
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#include <linux/ftrace.h>
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#include "trace.h"
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static struct trace_array *ctx_trace;
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static void start_nop_trace(struct trace_array *tr)
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{
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/* Nothing to do! */
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}
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static void stop_nop_trace(struct trace_array *tr)
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{
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/* Nothing to do! */
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}
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static int nop_trace_init(struct trace_array *tr)
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{
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int cpu;
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ctx_trace = tr;
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for_each_online_cpu(cpu)
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tracing_reset(tr, cpu);
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start_nop_trace(tr);
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return 0;
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}
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static void nop_trace_reset(struct trace_array *tr)
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{
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stop_nop_trace(tr);
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}
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struct tracer nop_trace __read_mostly =
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{
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.name = "nop",
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.init = nop_trace_init,
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.reset = nop_trace_reset,
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#ifdef CONFIG_FTRACE_SELFTEST
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.selftest = trace_selftest_startup_nop,
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#endif
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};
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