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> | |
35e8e302 | 12 | #include <linux/ftrace.h> |
b07c3f19 | 13 | #include <trace/sched.h> |
35e8e302 SR |
14 | |
15 | #include "trace.h" | |
16 | ||
17 | static struct trace_array *ctx_trace; | |
18 | static int __read_mostly tracer_enabled; | |
efade6e7 FW |
19 | static int sched_ref; |
20 | static DEFINE_MUTEX(sched_register_mutex); | |
35e8e302 | 21 | |
e309b41d | 22 | static void |
b07c3f19 | 23 | probe_sched_switch(struct rq *__rq, struct task_struct *prev, |
5b82a1b0 | 24 | struct task_struct *next) |
35e8e302 | 25 | { |
35e8e302 SR |
26 | struct trace_array_cpu *data; |
27 | unsigned long flags; | |
35e8e302 | 28 | int cpu; |
38697053 | 29 | int pc; |
35e8e302 | 30 | |
efade6e7 | 31 | if (!sched_ref) |
b07c3f19 MD |
32 | return; |
33 | ||
41bc8144 SR |
34 | tracing_record_cmdline(prev); |
35 | tracing_record_cmdline(next); | |
36 | ||
35e8e302 SR |
37 | if (!tracer_enabled) |
38 | return; | |
39 | ||
38697053 | 40 | pc = preempt_count(); |
18cef379 | 41 | local_irq_save(flags); |
35e8e302 | 42 | cpu = raw_smp_processor_id(); |
b07c3f19 | 43 | data = ctx_trace->data[cpu]; |
35e8e302 | 44 | |
3ea2e6d7 | 45 | if (likely(!atomic_read(&data->disabled))) |
38697053 | 46 | tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc); |
35e8e302 | 47 | |
18cef379 | 48 | local_irq_restore(flags); |
35e8e302 SR |
49 | } |
50 | ||
4e655519 | 51 | static void |
b07c3f19 | 52 | probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee) |
57422797 | 53 | { |
57422797 IM |
54 | struct trace_array_cpu *data; |
55 | unsigned long flags; | |
38697053 | 56 | int cpu, pc; |
57422797 | 57 | |
b07c3f19 | 58 | if (!likely(tracer_enabled)) |
57422797 IM |
59 | return; |
60 | ||
38697053 | 61 | pc = preempt_count(); |
b07c3f19 | 62 | tracing_record_cmdline(current); |
d9af56fb | 63 | |
57422797 IM |
64 | local_irq_save(flags); |
65 | cpu = raw_smp_processor_id(); | |
b07c3f19 | 66 | data = ctx_trace->data[cpu]; |
57422797 | 67 | |
3ea2e6d7 | 68 | if (likely(!atomic_read(&data->disabled))) |
b07c3f19 | 69 | tracing_sched_wakeup_trace(ctx_trace, data, wakee, current, |
38697053 | 70 | flags, pc); |
57422797 | 71 | |
57422797 IM |
72 | local_irq_restore(flags); |
73 | } | |
74 | ||
e309b41d | 75 | static void sched_switch_reset(struct trace_array *tr) |
35e8e302 SR |
76 | { |
77 | int cpu; | |
78 | ||
750ed1a4 | 79 | tr->time_start = ftrace_now(tr->cpu); |
35e8e302 SR |
80 | |
81 | for_each_online_cpu(cpu) | |
3928a8a2 | 82 | tracing_reset(tr, cpu); |
35e8e302 SR |
83 | } |
84 | ||
5b82a1b0 MD |
85 | static int tracing_sched_register(void) |
86 | { | |
87 | int ret; | |
88 | ||
b07c3f19 | 89 | ret = register_trace_sched_wakeup(probe_sched_wakeup); |
5b82a1b0 | 90 | if (ret) { |
b07c3f19 | 91 | pr_info("wakeup trace: Couldn't activate tracepoint" |
5b82a1b0 MD |
92 | " probe to kernel_sched_wakeup\n"); |
93 | return ret; | |
94 | } | |
95 | ||
b07c3f19 | 96 | ret = register_trace_sched_wakeup_new(probe_sched_wakeup); |
5b82a1b0 | 97 | if (ret) { |
b07c3f19 | 98 | pr_info("wakeup trace: Couldn't activate tracepoint" |
5b82a1b0 MD |
99 | " probe to kernel_sched_wakeup_new\n"); |
100 | goto fail_deprobe; | |
101 | } | |
102 | ||
b07c3f19 | 103 | ret = register_trace_sched_switch(probe_sched_switch); |
5b82a1b0 | 104 | if (ret) { |
b07c3f19 | 105 | pr_info("sched trace: Couldn't activate tracepoint" |
5b82a1b0 MD |
106 | " probe to kernel_sched_schedule\n"); |
107 | goto fail_deprobe_wake_new; | |
108 | } | |
109 | ||
110 | return ret; | |
111 | fail_deprobe_wake_new: | |
b07c3f19 | 112 | unregister_trace_sched_wakeup_new(probe_sched_wakeup); |
5b82a1b0 | 113 | fail_deprobe: |
b07c3f19 | 114 | unregister_trace_sched_wakeup(probe_sched_wakeup); |
5b82a1b0 MD |
115 | return ret; |
116 | } | |
117 | ||
118 | static void tracing_sched_unregister(void) | |
119 | { | |
b07c3f19 MD |
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); | |
5b82a1b0 MD |
123 | } |
124 | ||
f2252935 | 125 | static void tracing_start_sched_switch(void) |
5b82a1b0 | 126 | { |
efade6e7 FW |
127 | mutex_lock(&sched_register_mutex); |
128 | if (!(sched_ref++)) { | |
129 | tracer_enabled = 1; | |
5b82a1b0 | 130 | tracing_sched_register(); |
efade6e7 FW |
131 | } |
132 | mutex_unlock(&sched_register_mutex); | |
5b82a1b0 MD |
133 | } |
134 | ||
f2252935 | 135 | static void tracing_stop_sched_switch(void) |
5b82a1b0 | 136 | { |
efade6e7 FW |
137 | mutex_lock(&sched_register_mutex); |
138 | if (!(--sched_ref)) { | |
5b82a1b0 | 139 | tracing_sched_unregister(); |
efade6e7 FW |
140 | tracer_enabled = 0; |
141 | } | |
142 | mutex_unlock(&sched_register_mutex); | |
5b82a1b0 MD |
143 | } |
144 | ||
41bc8144 SR |
145 | void tracing_start_cmdline_record(void) |
146 | { | |
147 | tracing_start_sched_switch(); | |
148 | } | |
149 | ||
150 | void tracing_stop_cmdline_record(void) | |
151 | { | |
152 | tracing_stop_sched_switch(); | |
153 | } | |
154 | ||
75f5c47d SR |
155 | /** |
156 | * tracing_cmdline_assign_trace - assign a trace array for ctx switch | |
157 | * @tr: trace array pointer to assign | |
158 | * | |
159 | * Some tracers might want to record the context switches in their | |
160 | * trace. This function lets those tracers assign the trace array | |
161 | * to use. | |
162 | */ | |
163 | void tracing_cmdline_assign_trace(struct trace_array *tr) | |
164 | { | |
165 | ctx_trace = tr; | |
166 | } | |
167 | ||
e309b41d | 168 | static void start_sched_trace(struct trace_array *tr) |
35e8e302 SR |
169 | { |
170 | sched_switch_reset(tr); | |
41bc8144 | 171 | tracing_start_cmdline_record(); |
35e8e302 SR |
172 | } |
173 | ||
e309b41d | 174 | static void stop_sched_trace(struct trace_array *tr) |
35e8e302 | 175 | { |
007c05d4 | 176 | tracing_stop_cmdline_record(); |
35e8e302 SR |
177 | } |
178 | ||
e309b41d | 179 | static void sched_switch_trace_init(struct trace_array *tr) |
35e8e302 SR |
180 | { |
181 | ctx_trace = tr; | |
182 | ||
183 | if (tr->ctrl) | |
184 | start_sched_trace(tr); | |
185 | } | |
186 | ||
e309b41d | 187 | static void sched_switch_trace_reset(struct trace_array *tr) |
35e8e302 | 188 | { |
79a9d461 | 189 | if (tr->ctrl && sched_ref) |
35e8e302 SR |
190 | stop_sched_trace(tr); |
191 | } | |
192 | ||
193 | static void sched_switch_trace_ctrl_update(struct trace_array *tr) | |
194 | { | |
195 | /* When starting a new trace, reset the buffers */ | |
196 | if (tr->ctrl) | |
197 | start_sched_trace(tr); | |
198 | else | |
199 | stop_sched_trace(tr); | |
200 | } | |
201 | ||
9036990d SR |
202 | static void sched_switch_trace_start(struct trace_array *tr) |
203 | { | |
204 | sched_switch_reset(tr); | |
205 | tracing_start_sched_switch(); | |
206 | } | |
207 | ||
208 | static void sched_switch_trace_stop(struct trace_array *tr) | |
209 | { | |
210 | tracing_stop_sched_switch(); | |
211 | } | |
212 | ||
75f5c47d | 213 | static struct tracer sched_switch_trace __read_mostly = |
35e8e302 SR |
214 | { |
215 | .name = "sched_switch", | |
216 | .init = sched_switch_trace_init, | |
217 | .reset = sched_switch_trace_reset, | |
9036990d SR |
218 | .start = sched_switch_trace_start, |
219 | .stop = sched_switch_trace_stop, | |
35e8e302 | 220 | .ctrl_update = sched_switch_trace_ctrl_update, |
60a11774 SR |
221 | #ifdef CONFIG_FTRACE_SELFTEST |
222 | .selftest = trace_selftest_startup_sched_switch, | |
223 | #endif | |
35e8e302 SR |
224 | }; |
225 | ||
226 | __init static int init_sched_switch_trace(void) | |
227 | { | |
228 | return register_tracer(&sched_switch_trace); | |
229 | } | |
230 | device_initcall(init_sched_switch_trace); |