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
|
/*
* trace stack traces
*
* Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
* Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
*
*/
#include <linux/kallsyms.h>
#include <linux/debugfs.h>
#include <linux/hrtimer.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
#include <linux/module.h>
#include <linux/fs.h>
#include "trace.h"
static struct trace_array *ctx_trace;
static int __read_mostly tracer_enabled;
static const unsigned long sample_period = 1000000;
/*
* Per CPU hrtimers that do the profiling:
*/
static DEFINE_PER_CPU(struct hrtimer, stack_trace_hrtimer);
static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
{
/* trace here */
panic_timeout++;
hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
return HRTIMER_RESTART;
}
static void start_stack_timer(int cpu)
{
struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hrtimer->function = stack_trace_timer_fn;
hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
hrtimer_start(hrtimer, ns_to_ktime(sample_period), HRTIMER_MODE_REL);
}
static void start_stack_timers(void)
{
cpumask_t saved_mask = current->cpus_allowed;
int cpu;
for_each_online_cpu(cpu) {
set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
start_stack_timer(cpu);
printk("started timer on cpu%d\n", cpu);
}
set_cpus_allowed_ptr(current, &saved_mask);
}
static void stop_stack_timer(int cpu)
{
struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
hrtimer_cancel(hrtimer);
printk("cancelled timer on cpu%d\n", cpu);
}
static void stop_stack_timers(void)
{
int cpu;
for_each_online_cpu(cpu)
stop_stack_timer(cpu);
}
static notrace void stack_reset(struct trace_array *tr)
{
int cpu;
tr->time_start = ftrace_now(tr->cpu);
for_each_online_cpu(cpu)
tracing_reset(tr->data[cpu]);
}
static notrace void start_stack_trace(struct trace_array *tr)
{
stack_reset(tr);
start_stack_timers();
tracer_enabled = 1;
}
static notrace void stop_stack_trace(struct trace_array *tr)
{
stop_stack_timers();
tracer_enabled = 0;
}
static notrace void stack_trace_init(struct trace_array *tr)
{
ctx_trace = tr;
if (tr->ctrl)
start_stack_trace(tr);
}
static notrace void stack_trace_reset(struct trace_array *tr)
{
if (tr->ctrl)
stop_stack_trace(tr);
}
static void stack_trace_ctrl_update(struct trace_array *tr)
{
/* When starting a new trace, reset the buffers */
if (tr->ctrl)
start_stack_trace(tr);
else
stop_stack_trace(tr);
}
static struct tracer stack_trace __read_mostly =
{
.name = "sysprof",
.init = stack_trace_init,
.reset = stack_trace_reset,
.ctrl_update = stack_trace_ctrl_update,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_stack,
#endif
};
__init static int init_stack_trace(void)
{
return register_tracer(&stack_trace);
}
device_initcall(init_stack_trace);
|
