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>
78 lines
1.5 KiB
C
78 lines
1.5 KiB
C
/*
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* ring buffer based function tracer
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*
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* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
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* Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
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*
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* Based on code from the latency_tracer, that is:
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*
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* Copyright (C) 2004-2006 Ingo Molnar
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* Copyright (C) 2004 William Lee Irwin III
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*/
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#include <linux/debugfs.h>
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#include <linux/uaccess.h>
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#include <linux/ftrace.h>
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#include <linux/fs.h>
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#include "trace.h"
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static void function_reset(struct trace_array *tr)
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{
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int cpu;
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tr->time_start = ftrace_now(tr->cpu);
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for_each_online_cpu(cpu)
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tracing_reset(tr, cpu);
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}
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static void start_function_trace(struct trace_array *tr)
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{
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tr->cpu = get_cpu();
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function_reset(tr);
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put_cpu();
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tracing_start_cmdline_record();
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tracing_start_function_trace();
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}
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static void stop_function_trace(struct trace_array *tr)
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{
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tracing_stop_function_trace();
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tracing_stop_cmdline_record();
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}
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static int function_trace_init(struct trace_array *tr)
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{
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start_function_trace(tr);
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return 0;
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}
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static void function_trace_reset(struct trace_array *tr)
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{
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stop_function_trace(tr);
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}
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static void function_trace_start(struct trace_array *tr)
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{
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function_reset(tr);
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}
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static struct tracer function_trace __read_mostly =
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{
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.name = "function",
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.init = function_trace_init,
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.reset = function_trace_reset,
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.start = function_trace_start,
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#ifdef CONFIG_FTRACE_SELFTEST
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.selftest = trace_selftest_startup_function,
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#endif
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};
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static __init int init_function_trace(void)
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{
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return register_tracer(&function_trace);
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}
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device_initcall(init_function_trace);
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