1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
|
/*
* trace context switch
*
* Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
*
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
#include <trace/sched.h>
#include "trace.h"
static struct trace_array *ctx_trace;
static int __read_mostly tracer_enabled;
static int sched_ref;
static DEFINE_MUTEX(sched_register_mutex);
static void
probe_sched_switch(struct rq *__rq, struct task_struct *prev,
struct task_struct *next)
{
struct trace_array_cpu *data;
unsigned long flags;
int cpu;
int pc;
if (!sched_ref)
return;
tracing_record_cmdline(prev);
tracing_record_cmdline(next);
if (!tracer_enabled)
return;
pc = preempt_count();
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = ctx_trace->data[cpu];
if (likely(!atomic_read(&data->disabled)))
tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc);
local_irq_restore(flags);
}
static void
probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
{
struct trace_array_cpu *data;
unsigned long flags;
int cpu, pc;
if (!likely(tracer_enabled))
return;
pc = preempt_count();
tracing_record_cmdline(current);
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = ctx_trace->data[cpu];
if (likely(!atomic_read(&data->disabled)))
tracing_sched_wakeup_trace(ctx_trace, data, wakee, current,
flags, pc);
local_irq_restore(flags);
}
static int tracing_sched_register(void)
{
int ret;
ret = register_trace_sched_wakeup(probe_sched_wakeup);
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);
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);
if (ret) {
pr_info("sched trace: Couldn't activate tracepoint"
" probe to kernel_sched_schedule\n");
goto fail_deprobe_wake_new;
}
return ret;
fail_deprobe_wake_new:
unregister_trace_sched_wakeup_new(probe_sched_wakeup);
fail_deprobe:
unregister_trace_sched_wakeup(probe_sched_wakeup);
return ret;
}
static void tracing_sched_unregister(void)
{
unregister_trace_sched_switch(probe_sched_switch);
unregister_trace_sched_wakeup_new(probe_sched_wakeup);
unregister_trace_sched_wakeup(probe_sched_wakeup);
}
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();
}
/**
* tracing_start_sched_switch_record - start tracing context switches
*
* Turns on context switch tracing for a tracer.
*/
void tracing_start_sched_switch_record(void)
{
if (unlikely(!ctx_trace)) {
WARN_ON(1);
return;
}
tracing_start_sched_switch();
mutex_lock(&sched_register_mutex);
tracer_enabled++;
mutex_unlock(&sched_register_mutex);
}
/**
* tracing_stop_sched_switch_record - start tracing context switches
*
* Turns off context switch tracing for a tracer.
*/
void tracing_stop_sched_switch_record(void)
{
mutex_lock(&sched_register_mutex);
tracer_enabled--;
WARN_ON(tracer_enabled < 0);
mutex_unlock(&sched_register_mutex);
tracing_stop_sched_switch();
}
/**
* tracing_sched_switch_assign_trace - assign a trace array for ctx switch
* @tr: trace array pointer to assign
*
* Some tracers might want to record the context switches in their
* trace. This function lets those tracers assign the trace array
* to use.
*/
void tracing_sched_switch_assign_trace(struct trace_array *tr)
{
ctx_trace = tr;
}
static void start_sched_trace(struct trace_array *tr)
{
tracing_reset_online_cpus(tr);
tracing_start_sched_switch_record();
}
static void stop_sched_trace(struct trace_array *tr)
{
tracing_stop_sched_switch_record();
}
static int sched_switch_trace_init(struct trace_array *tr)
{
ctx_trace = tr;
start_sched_trace(tr);
return 0;
}
static void sched_switch_trace_reset(struct trace_array *tr)
{
if (sched_ref)
stop_sched_trace(tr);
}
static void sched_switch_trace_start(struct trace_array *tr)
{
tracing_reset_online_cpus(tr);
tracing_start_sched_switch();
}
static void sched_switch_trace_stop(struct trace_array *tr)
{
tracing_stop_sched_switch();
}
static struct tracer sched_switch_trace __read_mostly =
{
.name = "sched_switch",
.init = sched_switch_trace_init,
.reset = sched_switch_trace_reset,
.start = sched_switch_trace_start,
.stop = sched_switch_trace_stop,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_sched_switch,
#endif
};
__init static int init_sched_switch_trace(void)
{
return register_tracer(&sched_switch_trace);
}
device_initcall(init_sched_switch_trace);
|
