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Commit | Line | Data |
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35e8e302 SR |
1 | /* |
2 | * trace context switch | |
3 | * | |
4 | * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com> | |
5 | * | |
6 | */ | |
7 | #include <linux/module.h> | |
8 | #include <linux/fs.h> | |
9 | #include <linux/debugfs.h> | |
10 | #include <linux/kallsyms.h> | |
11 | #include <linux/uaccess.h> | |
12 | #include <linux/marker.h> | |
13 | #include <linux/ftrace.h> | |
14 | ||
15 | #include "trace.h" | |
16 | ||
17 | static struct trace_array *ctx_trace; | |
18 | static int __read_mostly tracer_enabled; | |
5b82a1b0 | 19 | static atomic_t sched_ref; |
35e8e302 | 20 | |
e309b41d | 21 | static void |
5b82a1b0 MD |
22 | sched_switch_func(void *private, void *__rq, struct task_struct *prev, |
23 | struct task_struct *next) | |
35e8e302 | 24 | { |
5b82a1b0 MD |
25 | struct trace_array **ptr = private; |
26 | struct trace_array *tr = *ptr; | |
35e8e302 SR |
27 | struct trace_array_cpu *data; |
28 | unsigned long flags; | |
29 | long disabled; | |
30 | int cpu; | |
31 | ||
41bc8144 SR |
32 | tracing_record_cmdline(prev); |
33 | tracing_record_cmdline(next); | |
34 | ||
35e8e302 SR |
35 | if (!tracer_enabled) |
36 | return; | |
37 | ||
18cef379 | 38 | local_irq_save(flags); |
35e8e302 SR |
39 | cpu = raw_smp_processor_id(); |
40 | data = tr->data[cpu]; | |
41 | disabled = atomic_inc_return(&data->disabled); | |
42 | ||
4d9493c9 | 43 | if (likely(disabled == 1)) |
35e8e302 SR |
44 | tracing_sched_switch_trace(tr, data, prev, next, flags); |
45 | ||
46 | atomic_dec(&data->disabled); | |
18cef379 | 47 | local_irq_restore(flags); |
35e8e302 SR |
48 | } |
49 | ||
5b82a1b0 MD |
50 | static notrace void |
51 | sched_switch_callback(void *probe_data, void *call_data, | |
52 | const char *format, va_list *args) | |
53 | { | |
54 | struct task_struct *prev; | |
55 | struct task_struct *next; | |
56 | struct rq *__rq; | |
57 | ||
58 | if (!atomic_read(&sched_ref)) | |
59 | return; | |
60 | ||
61 | /* skip prev_pid %d next_pid %d prev_state %ld */ | |
62 | (void)va_arg(*args, int); | |
63 | (void)va_arg(*args, int); | |
64 | (void)va_arg(*args, long); | |
65 | __rq = va_arg(*args, typeof(__rq)); | |
66 | prev = va_arg(*args, typeof(prev)); | |
67 | next = va_arg(*args, typeof(next)); | |
68 | ||
5b82a1b0 MD |
69 | /* |
70 | * If tracer_switch_func only points to the local | |
71 | * switch func, it still needs the ptr passed to it. | |
72 | */ | |
73 | sched_switch_func(probe_data, __rq, prev, next); | |
74 | } | |
75 | ||
4e655519 | 76 | static void |
5b82a1b0 MD |
77 | wakeup_func(void *private, void *__rq, struct task_struct *wakee, struct |
78 | task_struct *curr) | |
57422797 | 79 | { |
5b82a1b0 MD |
80 | struct trace_array **ptr = private; |
81 | struct trace_array *tr = *ptr; | |
57422797 IM |
82 | struct trace_array_cpu *data; |
83 | unsigned long flags; | |
84 | long disabled; | |
85 | int cpu; | |
86 | ||
87 | if (!tracer_enabled) | |
88 | return; | |
89 | ||
d9af56fb IM |
90 | tracing_record_cmdline(curr); |
91 | ||
57422797 IM |
92 | local_irq_save(flags); |
93 | cpu = raw_smp_processor_id(); | |
94 | data = tr->data[cpu]; | |
95 | disabled = atomic_inc_return(&data->disabled); | |
96 | ||
4d9493c9 | 97 | if (likely(disabled == 1)) |
57422797 IM |
98 | tracing_sched_wakeup_trace(tr, data, wakee, curr, flags); |
99 | ||
100 | atomic_dec(&data->disabled); | |
101 | local_irq_restore(flags); | |
102 | } | |
103 | ||
5b82a1b0 MD |
104 | static notrace void |
105 | wake_up_callback(void *probe_data, void *call_data, | |
106 | const char *format, va_list *args) | |
35e8e302 | 107 | { |
5b82a1b0 MD |
108 | struct task_struct *curr; |
109 | struct task_struct *task; | |
110 | struct rq *__rq; | |
25b0b44a | 111 | |
5b82a1b0 MD |
112 | if (likely(!tracer_enabled)) |
113 | return; | |
35e8e302 | 114 | |
5b82a1b0 MD |
115 | /* Skip pid %d state %ld */ |
116 | (void)va_arg(*args, int); | |
117 | (void)va_arg(*args, long); | |
118 | /* now get the meat: "rq %p task %p rq->curr %p" */ | |
119 | __rq = va_arg(*args, typeof(__rq)); | |
120 | task = va_arg(*args, typeof(task)); | |
121 | curr = va_arg(*args, typeof(curr)); | |
35e8e302 | 122 | |
5b82a1b0 MD |
123 | tracing_record_cmdline(task); |
124 | tracing_record_cmdline(curr); | |
57422797 | 125 | |
5b82a1b0 | 126 | wakeup_func(probe_data, __rq, task, curr); |
57422797 IM |
127 | } |
128 | ||
e309b41d | 129 | static void sched_switch_reset(struct trace_array *tr) |
35e8e302 SR |
130 | { |
131 | int cpu; | |
132 | ||
750ed1a4 | 133 | tr->time_start = ftrace_now(tr->cpu); |
35e8e302 SR |
134 | |
135 | for_each_online_cpu(cpu) | |
136 | tracing_reset(tr->data[cpu]); | |
137 | } | |
138 | ||
5b82a1b0 MD |
139 | static int tracing_sched_register(void) |
140 | { | |
141 | int ret; | |
142 | ||
143 | ret = marker_probe_register("kernel_sched_wakeup", | |
144 | "pid %d state %ld ## rq %p task %p rq->curr %p", | |
145 | wake_up_callback, | |
146 | &ctx_trace); | |
147 | if (ret) { | |
148 | pr_info("wakeup trace: Couldn't add marker" | |
149 | " probe to kernel_sched_wakeup\n"); | |
150 | return ret; | |
151 | } | |
152 | ||
153 | ret = marker_probe_register("kernel_sched_wakeup_new", | |
154 | "pid %d state %ld ## rq %p task %p rq->curr %p", | |
155 | wake_up_callback, | |
156 | &ctx_trace); | |
157 | if (ret) { | |
158 | pr_info("wakeup trace: Couldn't add marker" | |
159 | " probe to kernel_sched_wakeup_new\n"); | |
160 | goto fail_deprobe; | |
161 | } | |
162 | ||
163 | ret = marker_probe_register("kernel_sched_schedule", | |
164 | "prev_pid %d next_pid %d prev_state %ld " | |
165 | "## rq %p prev %p next %p", | |
166 | sched_switch_callback, | |
167 | &ctx_trace); | |
168 | if (ret) { | |
169 | pr_info("sched trace: Couldn't add marker" | |
170 | " probe to kernel_sched_schedule\n"); | |
171 | goto fail_deprobe_wake_new; | |
172 | } | |
173 | ||
174 | return ret; | |
175 | fail_deprobe_wake_new: | |
176 | marker_probe_unregister("kernel_sched_wakeup_new", | |
177 | wake_up_callback, | |
178 | &ctx_trace); | |
179 | fail_deprobe: | |
180 | marker_probe_unregister("kernel_sched_wakeup", | |
181 | wake_up_callback, | |
182 | &ctx_trace); | |
183 | return ret; | |
184 | } | |
185 | ||
186 | static void tracing_sched_unregister(void) | |
187 | { | |
188 | marker_probe_unregister("kernel_sched_schedule", | |
189 | sched_switch_callback, | |
190 | &ctx_trace); | |
191 | marker_probe_unregister("kernel_sched_wakeup_new", | |
192 | wake_up_callback, | |
193 | &ctx_trace); | |
194 | marker_probe_unregister("kernel_sched_wakeup", | |
195 | wake_up_callback, | |
196 | &ctx_trace); | |
197 | } | |
198 | ||
f2252935 | 199 | static void tracing_start_sched_switch(void) |
5b82a1b0 MD |
200 | { |
201 | long ref; | |
202 | ||
203 | ref = atomic_inc_return(&sched_ref); | |
204 | if (ref == 1) | |
205 | tracing_sched_register(); | |
206 | } | |
207 | ||
f2252935 | 208 | static void tracing_stop_sched_switch(void) |
5b82a1b0 MD |
209 | { |
210 | long ref; | |
211 | ||
212 | ref = atomic_dec_and_test(&sched_ref); | |
213 | if (ref) | |
214 | tracing_sched_unregister(); | |
215 | } | |
216 | ||
41bc8144 SR |
217 | void tracing_start_cmdline_record(void) |
218 | { | |
219 | tracing_start_sched_switch(); | |
220 | } | |
221 | ||
222 | void tracing_stop_cmdline_record(void) | |
223 | { | |
224 | tracing_stop_sched_switch(); | |
225 | } | |
226 | ||
e309b41d | 227 | static void start_sched_trace(struct trace_array *tr) |
35e8e302 SR |
228 | { |
229 | sched_switch_reset(tr); | |
41bc8144 | 230 | tracing_start_cmdline_record(); |
007c05d4 | 231 | tracer_enabled = 1; |
35e8e302 SR |
232 | } |
233 | ||
e309b41d | 234 | static void stop_sched_trace(struct trace_array *tr) |
35e8e302 SR |
235 | { |
236 | tracer_enabled = 0; | |
007c05d4 | 237 | tracing_stop_cmdline_record(); |
35e8e302 SR |
238 | } |
239 | ||
e309b41d | 240 | static void sched_switch_trace_init(struct trace_array *tr) |
35e8e302 SR |
241 | { |
242 | ctx_trace = tr; | |
243 | ||
244 | if (tr->ctrl) | |
245 | start_sched_trace(tr); | |
246 | } | |
247 | ||
e309b41d | 248 | static void sched_switch_trace_reset(struct trace_array *tr) |
35e8e302 SR |
249 | { |
250 | if (tr->ctrl) | |
251 | stop_sched_trace(tr); | |
252 | } | |
253 | ||
254 | static void sched_switch_trace_ctrl_update(struct trace_array *tr) | |
255 | { | |
256 | /* When starting a new trace, reset the buffers */ | |
257 | if (tr->ctrl) | |
258 | start_sched_trace(tr); | |
259 | else | |
260 | stop_sched_trace(tr); | |
261 | } | |
262 | ||
263 | static struct tracer sched_switch_trace __read_mostly = | |
264 | { | |
265 | .name = "sched_switch", | |
266 | .init = sched_switch_trace_init, | |
267 | .reset = sched_switch_trace_reset, | |
268 | .ctrl_update = sched_switch_trace_ctrl_update, | |
60a11774 SR |
269 | #ifdef CONFIG_FTRACE_SELFTEST |
270 | .selftest = trace_selftest_startup_sched_switch, | |
271 | #endif | |
35e8e302 SR |
272 | }; |
273 | ||
274 | __init static int init_sched_switch_trace(void) | |
275 | { | |
5b82a1b0 MD |
276 | int ret = 0; |
277 | ||
278 | if (atomic_read(&sched_ref)) | |
279 | ret = tracing_sched_register(); | |
280 | if (ret) { | |
281 | pr_info("error registering scheduler trace\n"); | |
282 | return ret; | |
283 | } | |
35e8e302 SR |
284 | return register_tracer(&sched_switch_trace); |
285 | } | |
286 | device_initcall(init_sched_switch_trace); |