4 * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
7 #include <linux/module.h>
9 #include <linux/debugfs.h>
10 #include <linux/kallsyms.h>
11 #include <linux/uaccess.h>
12 #include <linux/ftrace.h>
13 #include <trace/sched.h>
17 static struct trace_array
*ctx_trace
;
18 static int __read_mostly tracer_enabled
;
20 static DEFINE_MUTEX(sched_register_mutex
);
23 probe_sched_switch(struct rq
*__rq
, struct task_struct
*prev
,
24 struct task_struct
*next
)
26 struct trace_array_cpu
*data
;
34 tracing_record_cmdline(prev
);
35 tracing_record_cmdline(next
);
41 local_irq_save(flags
);
42 cpu
= raw_smp_processor_id();
43 data
= ctx_trace
->data
[cpu
];
45 if (likely(!atomic_read(&data
->disabled
)))
46 tracing_sched_switch_trace(ctx_trace
, data
, prev
, next
, flags
, pc
);
48 local_irq_restore(flags
);
52 probe_sched_wakeup(struct rq
*__rq
, struct task_struct
*wakee
)
54 struct trace_array_cpu
*data
;
58 if (!likely(tracer_enabled
))
62 tracing_record_cmdline(current
);
64 local_irq_save(flags
);
65 cpu
= raw_smp_processor_id();
66 data
= ctx_trace
->data
[cpu
];
68 if (likely(!atomic_read(&data
->disabled
)))
69 tracing_sched_wakeup_trace(ctx_trace
, data
, wakee
, current
,
72 local_irq_restore(flags
);
75 static void sched_switch_reset(struct trace_array
*tr
)
79 tr
->time_start
= ftrace_now(tr
->cpu
);
81 for_each_online_cpu(cpu
)
82 tracing_reset(tr
, cpu
);
85 static int tracing_sched_register(void)
89 ret
= register_trace_sched_wakeup(probe_sched_wakeup
);
91 pr_info("wakeup trace: Couldn't activate tracepoint"
92 " probe to kernel_sched_wakeup\n");
96 ret
= register_trace_sched_wakeup_new(probe_sched_wakeup
);
98 pr_info("wakeup trace: Couldn't activate tracepoint"
99 " probe to kernel_sched_wakeup_new\n");
103 ret
= register_trace_sched_switch(probe_sched_switch
);
105 pr_info("sched trace: Couldn't activate tracepoint"
106 " probe to kernel_sched_schedule\n");
107 goto fail_deprobe_wake_new
;
111 fail_deprobe_wake_new
:
112 unregister_trace_sched_wakeup_new(probe_sched_wakeup
);
114 unregister_trace_sched_wakeup(probe_sched_wakeup
);
118 static void tracing_sched_unregister(void)
120 unregister_trace_sched_switch(probe_sched_switch
);
121 unregister_trace_sched_wakeup_new(probe_sched_wakeup
);
122 unregister_trace_sched_wakeup(probe_sched_wakeup
);
125 static void tracing_start_sched_switch(void)
127 mutex_lock(&sched_register_mutex
);
128 if (!(sched_ref
++)) {
130 tracing_sched_register();
132 mutex_unlock(&sched_register_mutex
);
135 static void tracing_stop_sched_switch(void)
137 mutex_lock(&sched_register_mutex
);
138 if (!(--sched_ref
)) {
139 tracing_sched_unregister();
142 mutex_unlock(&sched_register_mutex
);
145 void tracing_start_cmdline_record(void)
147 tracing_start_sched_switch();
150 void tracing_stop_cmdline_record(void)
152 tracing_stop_sched_switch();
155 static void start_sched_trace(struct trace_array
*tr
)
157 sched_switch_reset(tr
);
158 tracing_start_cmdline_record();
161 static void stop_sched_trace(struct trace_array
*tr
)
163 tracing_stop_cmdline_record();
166 static void sched_switch_trace_init(struct trace_array
*tr
)
171 start_sched_trace(tr
);
174 static void sched_switch_trace_reset(struct trace_array
*tr
)
177 stop_sched_trace(tr
);
180 static void sched_switch_trace_ctrl_update(struct trace_array
*tr
)
182 /* When starting a new trace, reset the buffers */
184 start_sched_trace(tr
);
186 stop_sched_trace(tr
);
189 struct tracer sched_switch_trace __read_mostly
=
191 .name
= "sched_switch",
192 .init
= sched_switch_trace_init
,
193 .reset
= sched_switch_trace_reset
,
194 .ctrl_update
= sched_switch_trace_ctrl_update
,
195 #ifdef CONFIG_FTRACE_SELFTEST
196 .selftest
= trace_selftest_startup_sched_switch
,
200 __init
static int init_sched_switch_trace(void)
202 return register_tracer(&sched_switch_trace
);
204 device_initcall(init_sched_switch_trace
);