Merge tag '4.3-rc-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6
[sfrench/cifs-2.6.git] / kernel / trace / trace_sched_switch.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * trace context switch
4  *
5  * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
6  *
7  */
8 #include <linux/module.h>
9 #include <linux/kallsyms.h>
10 #include <linux/uaccess.h>
11 #include <linux/ftrace.h>
12 #include <trace/events/sched.h>
13
14 #include "trace.h"
15
16 #define RECORD_CMDLINE  1
17 #define RECORD_TGID     2
18
19 static int              sched_cmdline_ref;
20 static int              sched_tgid_ref;
21 static DEFINE_MUTEX(sched_register_mutex);
22
23 static void
24 probe_sched_switch(void *ignore, bool preempt,
25                    struct task_struct *prev, struct task_struct *next)
26 {
27         int flags;
28
29         flags = (RECORD_TGID * !!sched_tgid_ref) +
30                 (RECORD_CMDLINE * !!sched_cmdline_ref);
31
32         if (!flags)
33                 return;
34         tracing_record_taskinfo_sched_switch(prev, next, flags);
35 }
36
37 static void
38 probe_sched_wakeup(void *ignore, struct task_struct *wakee)
39 {
40         int flags;
41
42         flags = (RECORD_TGID * !!sched_tgid_ref) +
43                 (RECORD_CMDLINE * !!sched_cmdline_ref);
44
45         if (!flags)
46                 return;
47         tracing_record_taskinfo(current, flags);
48 }
49
50 static int tracing_sched_register(void)
51 {
52         int ret;
53
54         ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL);
55         if (ret) {
56                 pr_info("wakeup trace: Couldn't activate tracepoint"
57                         " probe to kernel_sched_wakeup\n");
58                 return ret;
59         }
60
61         ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
62         if (ret) {
63                 pr_info("wakeup trace: Couldn't activate tracepoint"
64                         " probe to kernel_sched_wakeup_new\n");
65                 goto fail_deprobe;
66         }
67
68         ret = register_trace_sched_switch(probe_sched_switch, NULL);
69         if (ret) {
70                 pr_info("sched trace: Couldn't activate tracepoint"
71                         " probe to kernel_sched_switch\n");
72                 goto fail_deprobe_wake_new;
73         }
74
75         return ret;
76 fail_deprobe_wake_new:
77         unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
78 fail_deprobe:
79         unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
80         return ret;
81 }
82
83 static void tracing_sched_unregister(void)
84 {
85         unregister_trace_sched_switch(probe_sched_switch, NULL);
86         unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
87         unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
88 }
89
90 static void tracing_start_sched_switch(int ops)
91 {
92         bool sched_register = (!sched_cmdline_ref && !sched_tgid_ref);
93         mutex_lock(&sched_register_mutex);
94
95         switch (ops) {
96         case RECORD_CMDLINE:
97                 sched_cmdline_ref++;
98                 break;
99
100         case RECORD_TGID:
101                 sched_tgid_ref++;
102                 break;
103         }
104
105         if (sched_register && (sched_cmdline_ref || sched_tgid_ref))
106                 tracing_sched_register();
107         mutex_unlock(&sched_register_mutex);
108 }
109
110 static void tracing_stop_sched_switch(int ops)
111 {
112         mutex_lock(&sched_register_mutex);
113
114         switch (ops) {
115         case RECORD_CMDLINE:
116                 sched_cmdline_ref--;
117                 break;
118
119         case RECORD_TGID:
120                 sched_tgid_ref--;
121                 break;
122         }
123
124         if (!sched_cmdline_ref && !sched_tgid_ref)
125                 tracing_sched_unregister();
126         mutex_unlock(&sched_register_mutex);
127 }
128
129 void tracing_start_cmdline_record(void)
130 {
131         tracing_start_sched_switch(RECORD_CMDLINE);
132 }
133
134 void tracing_stop_cmdline_record(void)
135 {
136         tracing_stop_sched_switch(RECORD_CMDLINE);
137 }
138
139 void tracing_start_tgid_record(void)
140 {
141         tracing_start_sched_switch(RECORD_TGID);
142 }
143
144 void tracing_stop_tgid_record(void)
145 {
146         tracing_stop_sched_switch(RECORD_TGID);
147 }