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e1112b4d96
This patch adds run-time field descriptions to all the event formats exported using TRACE_EVENT_FORMAT. It also hooks up all the tracers that use them (i.e. the tracers in the 'ftrace subsystem') so they can also have their output filtered by the event-filtering mechanism. When I was testing this, there were a couple of things that fooled me into thinking the filters weren't working, when actually they were - I'll mention them here so others don't make the same mistakes (and file bug reports. ;-) One is that some of the tracers trace multiple events e.g. the sched_switch tracer uses the context_switch and wakeup events, and if you don't set filters on all of the traced events, the unfiltered output from the events without filters on them can make it look like the filtering as a whole isn't working properly, when actually it is doing what it was asked to do - it just wasn't asked to do the right thing. The other is that for the really high-volume tracers e.g. the function tracer, the volume of filtered events can be so high that it pushes the unfiltered events out of the ring buffer before they can be read so e.g. cat'ing the trace file repeatedly shows either no output, or once in awhile some output but that isn't there the next time you read the trace, which isn't what you normally expect when reading the trace file. If you read from the trace_pipe file though, you can catch them before they disappear. Changes from v1: As suggested by Frederic Weisbecker: - get rid of externs in functions - added unlikely() to filter_check_discard() Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
153 lines
4 KiB
C
153 lines
4 KiB
C
/*
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* trace_export.c - export basic ftrace utilities to user space
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*
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* Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
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*/
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#include <linux/stringify.h>
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#include <linux/kallsyms.h>
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#include <linux/seq_file.h>
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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/module.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include "trace_output.h"
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#undef TRACE_STRUCT
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#define TRACE_STRUCT(args...) args
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#undef TRACE_FIELD
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#define TRACE_FIELD(type, item, assign) \
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ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \
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"offset:%u;\tsize:%u;\n", \
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(unsigned int)offsetof(typeof(field), item), \
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(unsigned int)sizeof(field.item)); \
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if (!ret) \
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return 0;
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#undef TRACE_FIELD_SPECIAL
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#define TRACE_FIELD_SPECIAL(type_item, item, len, cmd) \
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ret = trace_seq_printf(s, "\tfield special:" #type_item ";\t" \
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"offset:%u;\tsize:%u;\n", \
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(unsigned int)offsetof(typeof(field), item), \
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(unsigned int)sizeof(field.item)); \
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if (!ret) \
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return 0;
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#undef TRACE_FIELD_ZERO_CHAR
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#define TRACE_FIELD_ZERO_CHAR(item) \
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ret = trace_seq_printf(s, "\tfield:char " #item ";\t" \
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"offset:%u;\tsize:0;\n", \
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(unsigned int)offsetof(typeof(field), item)); \
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if (!ret) \
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return 0;
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#undef TP_RAW_FMT
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#define TP_RAW_FMT(args...) args
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#undef TRACE_EVENT_FORMAT
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#define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt) \
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static int \
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ftrace_format_##call(struct trace_seq *s) \
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{ \
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struct args field; \
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int ret; \
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\
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tstruct; \
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\
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trace_seq_printf(s, "\nprint fmt: \"%s\"\n", tpfmt); \
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\
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return ret; \
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}
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#include "trace_event_types.h"
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#undef TRACE_ZERO_CHAR
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#define TRACE_ZERO_CHAR(arg)
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#undef TRACE_FIELD
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#define TRACE_FIELD(type, item, assign)\
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entry->item = assign;
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#undef TRACE_FIELD
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#define TRACE_FIELD(type, item, assign)\
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entry->item = assign;
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#undef TP_CMD
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#define TP_CMD(cmd...) cmd
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#undef TRACE_ENTRY
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#define TRACE_ENTRY entry
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#undef TRACE_FIELD_SPECIAL
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#define TRACE_FIELD_SPECIAL(type_item, item, len, cmd) \
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cmd;
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#undef TRACE_EVENT_FORMAT
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#define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt) \
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int ftrace_define_fields_##call(void); \
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static int ftrace_raw_init_event_##call(void); \
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\
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struct ftrace_event_call __used \
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__attribute__((__aligned__(4))) \
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__attribute__((section("_ftrace_events"))) event_##call = { \
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.name = #call, \
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.id = proto, \
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.system = __stringify(TRACE_SYSTEM), \
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.raw_init = ftrace_raw_init_event_##call, \
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.show_format = ftrace_format_##call, \
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.define_fields = ftrace_define_fields_##call, \
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}; \
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static int ftrace_raw_init_event_##call(void) \
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{ \
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INIT_LIST_HEAD(&event_##call.fields); \
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return 0; \
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} \
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#include "trace_event_types.h"
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#undef TRACE_FIELD
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#define TRACE_FIELD(type, item, assign) \
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ret = trace_define_field(event_call, #type, #item, \
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offsetof(typeof(field), item), \
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sizeof(field.item)); \
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if (ret) \
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return ret;
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#undef TRACE_FIELD_SPECIAL
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#define TRACE_FIELD_SPECIAL(type, item, len, cmd) \
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ret = trace_define_field(event_call, #type "[" #len "]", #item, \
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offsetof(typeof(field), item), \
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sizeof(field.item)); \
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if (ret) \
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return ret;
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#undef TRACE_FIELD_ZERO_CHAR
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#define TRACE_FIELD_ZERO_CHAR(item)
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#undef TRACE_EVENT_FORMAT
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#define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt) \
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int \
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ftrace_define_fields_##call(void) \
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{ \
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struct ftrace_event_call *event_call = &event_##call; \
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struct args field; \
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int ret; \
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\
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__common_field(unsigned char, type); \
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__common_field(unsigned char, flags); \
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__common_field(unsigned char, preempt_count); \
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__common_field(int, pid); \
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__common_field(int, tgid); \
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\
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tstruct; \
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\
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return ret; \
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}
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#include "trace_event_types.h"
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