2008-05-12 21:20:42 +02:00
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/*
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* trace context switch
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*
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* Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
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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/kallsyms.h>
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#include <linux/uaccess.h>
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#include <linux/ftrace.h>
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2008-07-18 18:16:17 +02:00
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#include <trace/sched.h>
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2008-05-12 21:20:42 +02:00
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#include "trace.h"
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static struct trace_array *ctx_trace;
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static int __read_mostly tracer_enabled;
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2008-05-12 21:21:10 +02:00
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static atomic_t sched_ref;
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2008-10-31 13:08:28 +01:00
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static DEFINE_MUTEX(tracepoint_mutex);
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2008-05-12 21:20:42 +02:00
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2008-05-12 21:20:51 +02:00
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static void
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2008-07-18 18:16:17 +02:00
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probe_sched_switch(struct rq *__rq, struct task_struct *prev,
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2008-05-12 21:21:10 +02:00
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struct task_struct *next)
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2008-05-12 21:20:42 +02:00
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{
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struct trace_array_cpu *data;
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unsigned long flags;
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int cpu;
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2008-10-01 19:14:09 +02:00
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int pc;
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2008-05-12 21:20:42 +02:00
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2008-07-18 18:16:17 +02:00
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if (!atomic_read(&sched_ref))
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return;
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2008-05-22 17:49:22 +02:00
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tracing_record_cmdline(prev);
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tracing_record_cmdline(next);
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2008-05-12 21:20:42 +02:00
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if (!tracer_enabled)
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return;
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2008-10-01 19:14:09 +02:00
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pc = preempt_count();
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2008-05-12 21:20:44 +02:00
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local_irq_save(flags);
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2008-05-12 21:20:42 +02:00
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cpu = raw_smp_processor_id();
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2008-07-18 18:16:17 +02:00
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data = ctx_trace->data[cpu];
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2008-05-12 21:20:42 +02:00
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2008-10-04 08:01:00 +02:00
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if (likely(!atomic_read(&data->disabled)))
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2008-10-01 19:14:09 +02:00
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tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc);
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2008-05-12 21:20:42 +02:00
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2008-05-12 21:20:44 +02:00
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local_irq_restore(flags);
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2008-05-12 21:20:42 +02:00
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}
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2008-05-12 21:20:52 +02:00
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static void
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2008-07-18 18:16:17 +02:00
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probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee)
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2008-05-12 21:20:51 +02:00
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{
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struct trace_array_cpu *data;
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unsigned long flags;
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2008-10-01 19:14:09 +02:00
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int cpu, pc;
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2008-05-12 21:20:51 +02:00
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2008-07-18 18:16:17 +02:00
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if (!likely(tracer_enabled))
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2008-05-12 21:20:51 +02:00
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return;
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2008-10-01 19:14:09 +02:00
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pc = preempt_count();
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2008-07-18 18:16:17 +02:00
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tracing_record_cmdline(current);
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2008-05-12 21:20:53 +02:00
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2008-05-12 21:20:51 +02:00
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local_irq_save(flags);
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cpu = raw_smp_processor_id();
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2008-07-18 18:16:17 +02:00
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data = ctx_trace->data[cpu];
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2008-05-12 21:20:51 +02:00
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2008-10-04 08:01:00 +02:00
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if (likely(!atomic_read(&data->disabled)))
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2008-07-18 18:16:17 +02:00
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tracing_sched_wakeup_trace(ctx_trace, data, wakee, current,
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2008-10-01 19:14:09 +02:00
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flags, pc);
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2008-05-12 21:20:51 +02:00
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local_irq_restore(flags);
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}
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2008-05-12 21:20:51 +02:00
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static void sched_switch_reset(struct trace_array *tr)
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2008-05-12 21:20:42 +02:00
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{
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int cpu;
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2008-05-12 21:20:46 +02:00
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tr->time_start = ftrace_now(tr->cpu);
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2008-05-12 21:20:42 +02:00
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for_each_online_cpu(cpu)
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2008-09-30 05:02:41 +02:00
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tracing_reset(tr, cpu);
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2008-05-12 21:20:42 +02:00
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}
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2008-05-12 21:21:10 +02:00
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static int tracing_sched_register(void)
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{
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int ret;
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2008-07-18 18:16:17 +02:00
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ret = register_trace_sched_wakeup(probe_sched_wakeup);
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2008-05-12 21:21:10 +02:00
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if (ret) {
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2008-07-18 18:16:17 +02:00
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pr_info("wakeup trace: Couldn't activate tracepoint"
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2008-05-12 21:21:10 +02:00
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" probe to kernel_sched_wakeup\n");
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return ret;
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}
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2008-07-18 18:16:17 +02:00
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ret = register_trace_sched_wakeup_new(probe_sched_wakeup);
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2008-05-12 21:21:10 +02:00
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if (ret) {
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2008-07-18 18:16:17 +02:00
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pr_info("wakeup trace: Couldn't activate tracepoint"
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2008-05-12 21:21:10 +02:00
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" probe to kernel_sched_wakeup_new\n");
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goto fail_deprobe;
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}
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2008-07-18 18:16:17 +02:00
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ret = register_trace_sched_switch(probe_sched_switch);
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2008-05-12 21:21:10 +02:00
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if (ret) {
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2008-07-18 18:16:17 +02:00
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pr_info("sched trace: Couldn't activate tracepoint"
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2008-05-12 21:21:10 +02:00
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" probe to kernel_sched_schedule\n");
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goto fail_deprobe_wake_new;
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}
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return ret;
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fail_deprobe_wake_new:
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2008-07-18 18:16:17 +02:00
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unregister_trace_sched_wakeup_new(probe_sched_wakeup);
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2008-05-12 21:21:10 +02:00
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fail_deprobe:
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2008-07-18 18:16:17 +02:00
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unregister_trace_sched_wakeup(probe_sched_wakeup);
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2008-05-12 21:21:10 +02:00
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return ret;
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}
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static void tracing_sched_unregister(void)
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{
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2008-07-18 18:16:17 +02:00
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unregister_trace_sched_switch(probe_sched_switch);
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unregister_trace_sched_wakeup_new(probe_sched_wakeup);
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unregister_trace_sched_wakeup(probe_sched_wakeup);
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2008-05-12 21:21:10 +02:00
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}
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2008-05-22 10:37:48 +02:00
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static void tracing_start_sched_switch(void)
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2008-05-12 21:21:10 +02:00
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{
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long ref;
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2008-10-31 13:08:28 +01:00
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mutex_lock(&tracepoint_mutex);
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2008-10-31 13:20:08 +01:00
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tracer_enabled = 1;
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2008-05-12 21:21:10 +02:00
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ref = atomic_inc_return(&sched_ref);
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if (ref == 1)
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tracing_sched_register();
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2008-10-31 13:08:28 +01:00
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mutex_unlock(&tracepoint_mutex);
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2008-05-12 21:21:10 +02:00
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}
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2008-05-22 10:37:48 +02:00
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static void tracing_stop_sched_switch(void)
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2008-05-12 21:21:10 +02:00
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{
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long ref;
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2008-10-31 13:08:28 +01:00
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mutex_lock(&tracepoint_mutex);
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2008-10-31 13:20:08 +01:00
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tracer_enabled = 0;
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2008-05-12 21:21:10 +02:00
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ref = atomic_dec_and_test(&sched_ref);
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if (ref)
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tracing_sched_unregister();
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2008-10-31 13:08:28 +01:00
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mutex_unlock(&tracepoint_mutex);
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2008-05-12 21:21:10 +02:00
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}
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2008-05-22 17:49:22 +02:00
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void tracing_start_cmdline_record(void)
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{
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tracing_start_sched_switch();
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}
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void tracing_stop_cmdline_record(void)
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{
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tracing_stop_sched_switch();
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}
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2008-05-12 21:20:51 +02:00
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static void start_sched_trace(struct trace_array *tr)
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2008-05-12 21:20:42 +02:00
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{
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sched_switch_reset(tr);
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2008-05-22 17:49:22 +02:00
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tracing_start_cmdline_record();
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2008-05-12 21:20:42 +02:00
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}
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2008-05-12 21:20:51 +02:00
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static void stop_sched_trace(struct trace_array *tr)
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2008-05-12 21:20:42 +02:00
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{
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2008-07-11 02:58:09 +02:00
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tracing_stop_cmdline_record();
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2008-05-12 21:20:42 +02:00
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}
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2008-05-12 21:20:51 +02:00
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static void sched_switch_trace_init(struct trace_array *tr)
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2008-05-12 21:20:42 +02:00
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{
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ctx_trace = tr;
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if (tr->ctrl)
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start_sched_trace(tr);
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}
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2008-05-12 21:20:51 +02:00
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static void sched_switch_trace_reset(struct trace_array *tr)
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2008-05-12 21:20:42 +02:00
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{
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if (tr->ctrl)
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stop_sched_trace(tr);
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}
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static void sched_switch_trace_ctrl_update(struct trace_array *tr)
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{
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/* When starting a new trace, reset the buffers */
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if (tr->ctrl)
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start_sched_trace(tr);
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else
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stop_sched_trace(tr);
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}
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2008-10-31 13:20:08 +01:00
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struct tracer sched_switch_trace __read_mostly =
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2008-05-12 21:20:42 +02:00
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{
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.name = "sched_switch",
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.init = sched_switch_trace_init,
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.reset = sched_switch_trace_reset,
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.ctrl_update = sched_switch_trace_ctrl_update,
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2008-05-12 21:20:44 +02:00
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#ifdef CONFIG_FTRACE_SELFTEST
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.selftest = trace_selftest_startup_sched_switch,
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#endif
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2008-05-12 21:20:42 +02:00
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};
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__init static int init_sched_switch_trace(void)
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{
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return register_tracer(&sched_switch_trace);
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}
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device_initcall(init_sched_switch_trace);
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