/* * trace context switch * * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com> * */#include <linux/module.h>#include <linux/kallsyms.h>#include <linux/uaccess.h>#include <linux/ftrace.h>#include <trace/events/sched.h> #include "trace.h" static int			sched_ref;static DEFINE_MUTEX(sched_register_mutex); static voidprobe_sched_switch(void *ignore, struct task_struct *prev, struct task_struct *next){	if (unlikely(!sched_ref))		return; 	tracing_record_cmdline(prev);	tracing_record_cmdline(next);} static voidprobe_sched_wakeup(void *ignore, struct task_struct *wakee){	if (unlikely(!sched_ref))		return; 	tracing_record_cmdline(current);} static int tracing_sched_register(void){	int ret; 	ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL);	if (ret) {		pr_info("wakeup trace: Couldn't activate tracepoint"			" probe to kernel_sched_wakeup\n");		return ret;	} 	ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL);	if (ret) {		pr_info("wakeup trace: Couldn't activate tracepoint"			" probe to kernel_sched_wakeup_new\n");		goto fail_deprobe;	} 	ret = register_trace_sched_switch(probe_sched_switch, NULL);	if (ret) {		pr_info("sched trace: Couldn't activate tracepoint"			" probe to kernel_sched_switch\n");		goto fail_deprobe_wake_new;	} 	return ret;fail_deprobe_wake_new:	unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);fail_deprobe:	unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);	return ret;} static void tracing_sched_unregister(void){	unregister_trace_sched_switch(probe_sched_switch, NULL);	unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);	unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);} static void tracing_start_sched_switch(void){	mutex_lock(&sched_register_mutex);	if (!(sched_ref++))		tracing_sched_register();	mutex_unlock(&sched_register_mutex);} static void tracing_stop_sched_switch(void){	mutex_lock(&sched_register_mutex);	if (!(--sched_ref))		tracing_sched_unregister();	mutex_unlock(&sched_register_mutex);} void tracing_start_cmdline_record(void){	tracing_start_sched_switch();} void tracing_stop_cmdline_record(void){	tracing_stop_sched_switch();}