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
use cell::UnsafeCell;
use intrinsics::{atomic_cxchg, atomic_xchg};
use ptr;
use sys::syscall::{futex, getpid, FUTEX_WAIT, FUTEX_WAKE};
pub unsafe fn mutex_try_lock(m: *mut i32) -> bool {
atomic_cxchg(m, 0, 1).0 == 0
}
pub unsafe fn mutex_lock(m: *mut i32) {
let mut c = 0;
for _i in 0..100 {
c = atomic_cxchg(m, 0, 1).0;
if c == 0 {
break;
}
}
if c == 1 {
c = atomic_xchg(m, 2);
}
while c != 0 {
let _ = futex(m, FUTEX_WAIT, 2, 0, ptr::null_mut());
c = atomic_xchg(m, 2);
}
}
pub unsafe fn mutex_unlock(m: *mut i32) {
if *m == 2 {
*m = 0;
} else if atomic_xchg(m, 0) == 1 {
return;
}
for _i in 0..100 {
if *m != 0 {
if atomic_cxchg(m, 1, 2).0 != 0 {
return;
}
}
}
let _ = futex(m, FUTEX_WAKE, 1, 0, ptr::null_mut());
}
pub struct Mutex {
pub lock: UnsafeCell<i32>,
}
impl Mutex {
pub const fn new() -> Self {
Mutex {
lock: UnsafeCell::new(0),
}
}
#[inline]
pub unsafe fn init(&self) {
*self.lock.get() = 0;
}
#[inline]
pub unsafe fn try_lock(&self) -> bool {
mutex_try_lock(self.lock.get())
}
#[inline]
pub unsafe fn lock(&self) {
mutex_lock(self.lock.get());
}
#[inline]
pub unsafe fn unlock(&self) {
mutex_unlock(self.lock.get());
}
#[inline]
pub unsafe fn destroy(&self) {
*self.lock.get() = 0;
}
}
unsafe impl Send for Mutex {}
unsafe impl Sync for Mutex {}
pub struct ReentrantMutex {
pub lock: UnsafeCell<i32>,
pub owner: UnsafeCell<usize>,
pub own_count: UnsafeCell<usize>,
}
impl ReentrantMutex {
pub const fn uninitialized() -> Self {
ReentrantMutex {
lock: UnsafeCell::new(0),
owner: UnsafeCell::new(0),
own_count: UnsafeCell::new(0),
}
}
#[inline]
pub unsafe fn init(&mut self) {
*self.lock.get() = 0;
*self.owner.get() = 0;
*self.own_count.get() = 0;
}
#[inline]
pub unsafe fn try_lock(&self) -> bool {
let pid = getpid().unwrap();
if *self.own_count.get() > 0 && *self.owner.get() == pid {
*self.own_count.get() += 1;
true
} else {
if mutex_try_lock(self.lock.get()) {
*self.owner.get() = pid;
*self.own_count.get() = 1;
true
} else {
false
}
}
}
#[inline]
pub unsafe fn lock(&self) {
let pid = getpid().unwrap();
if *self.own_count.get() > 0 && *self.owner.get() == pid {
*self.own_count.get() += 1;
} else {
mutex_lock(self.lock.get());
*self.owner.get() = pid;
*self.own_count.get() = 1;
}
}
#[inline]
pub unsafe fn unlock(&self) {
let pid = getpid().unwrap();
if *self.own_count.get() > 0 && *self.owner.get() == pid {
*self.own_count.get() -= 1;
if *self.own_count.get() == 0 {
*self.owner.get() = 0;
mutex_unlock(self.lock.get());
}
}
}
#[inline]
pub unsafe fn destroy(&self) {
*self.lock.get() = 0;
*self.owner.get() = 0;
*self.own_count.get() = 0;
}
}
unsafe impl Send for ReentrantMutex {}
unsafe impl Sync for ReentrantMutex {}