1427cdf059
Impact: save on memory for tracing Current tracers are typically using a struct(like struct ftrace_entry, struct ctx_switch_entry, struct special_entr etc...)to record a binary event. These structs can only record a their own kind of events. A new kind of tracer need a new struct and a lot of code too handle it. So we need a generic binary record for events. This infrastructure is for this purpose. [fweisbec@gmail.com: rebase against latest -tip, make it safe while sched tracing as reported by Steven Rostedt] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
88 lines
1.6 KiB
C
88 lines
1.6 KiB
C
/*
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* trace binary printk
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*
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* Copyright (C) 2008 Lai Jiangshan <laijs@cn.fujitsu.com>
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*
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*/
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#include <linux/kernel.h>
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#include <linux/ftrace.h>
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#include <linux/string.h>
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#include <linux/ctype.h>
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#include <linux/list.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/seq_file.h>
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#include <linux/fs.h>
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#include <linux/marker.h>
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#include <linux/uaccess.h>
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#include "trace.h"
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/* binary printk basic */
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static DEFINE_MUTEX(btrace_mutex);
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static int btrace_metadata_count;
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static inline void lock_btrace(void)
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{
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mutex_lock(&btrace_mutex);
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}
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static inline void unlock_btrace(void)
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{
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mutex_unlock(&btrace_mutex);
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}
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static void get_btrace_metadata(void)
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{
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lock_btrace();
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btrace_metadata_count++;
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unlock_btrace();
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}
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static void put_btrace_metadata(void)
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{
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lock_btrace();
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btrace_metadata_count--;
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unlock_btrace();
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}
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/* events tracer */
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int trace_bprintk_enable;
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static void start_bprintk_trace(struct trace_array *tr)
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{
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get_btrace_metadata();
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tracing_reset_online_cpus(tr);
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trace_bprintk_enable = 1;
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}
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static void stop_bprintk_trace(struct trace_array *tr)
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{
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trace_bprintk_enable = 0;
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tracing_reset_online_cpus(tr);
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put_btrace_metadata();
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}
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static int init_bprintk_trace(struct trace_array *tr)
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{
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start_bprintk_trace(tr);
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return 0;
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}
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static struct tracer bprintk_trace __read_mostly =
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{
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.name = "events",
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.init = init_bprintk_trace,
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.reset = stop_bprintk_trace,
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.start = start_bprintk_trace,
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.stop = stop_bprintk_trace,
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};
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static __init int init_bprintk(void)
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{
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return register_tracer(&bprintk_trace);
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}
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device_initcall(init_bprintk);
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