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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
/*
* Copyright (c) 2017 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef included_clib_lock_h
#define included_clib_lock_h
#include <vppinfra/clib.h>
#include <vppinfra/atomics.h>
#if __x86_64__
#define CLIB_PAUSE() __builtin_ia32_pause ()
#elif defined (__aarch64__) || defined (__arm__)
#define CLIB_PAUSE() __asm__ ("yield")
#else
#define CLIB_PAUSE()
#endif
#if CLIB_DEBUG > 1
#define CLIB_LOCK_DBG(_p) \
do { \
(*_p)->frame_address = __builtin_frame_address (0); \
(*_p)->pid = getpid (); \
(*_p)->thread_index = os_get_thread_index (); \
} while (0)
#define CLIB_LOCK_DBG_CLEAR(_p) \
do { \
(*_p)->frame_address = 0; \
(*_p)->pid = 0; \
(*_p)->thread_index = 0; \
} while (0)
#else
#define CLIB_LOCK_DBG(_p)
#define CLIB_LOCK_DBG_CLEAR(_p)
#endif
#define CLIB_SPINLOCK_IS_LOCKED(_p) (*(_p))->lock
#define CLIB_SPINLOCK_ASSERT_LOCKED(_p) ASSERT(CLIB_SPINLOCK_IS_LOCKED((_p)))
struct clib_spinlock_s
{
CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
u32 lock;
#if CLIB_DEBUG > 0
pid_t pid;
uword thread_index;
void *frame_address;
#endif
};
typedef struct clib_spinlock_s *clib_spinlock_t;
static inline void
clib_spinlock_init (clib_spinlock_t * p)
{
*p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
}
static inline void
clib_spinlock_free (clib_spinlock_t * p)
{
if (*p)
{
clib_mem_free ((void *) *p);
*p = 0;
}
}
static_always_inline void
clib_spinlock_lock (clib_spinlock_t * p)
{
u32 free = 0;
while (!clib_atomic_cmp_and_swap_acq_relax_n (&(*p)->lock, &free, 1, 0))
{
/* atomic load limits number of compare_exchange executions */
while (clib_atomic_load_relax_n (&(*p)->lock))
CLIB_PAUSE ();
/* on failure, compare_exchange writes (*p)->lock into free */
free = 0;
}
CLIB_LOCK_DBG (p);
}
static_always_inline int
clib_spinlock_trylock (clib_spinlock_t * p)
{
if (PREDICT_FALSE (CLIB_SPINLOCK_IS_LOCKED (p)))
return 0;
clib_spinlock_lock (p);
return 1;
}
static_always_inline void
clib_spinlock_lock_if_init (clib_spinlock_t * p)
{
if (PREDICT_FALSE (*p != 0))
clib_spinlock_lock (p);
}
static_always_inline int
clib_spinlock_trylock_if_init (clib_spinlock_t * p)
{
if (PREDICT_FALSE (*p != 0))
return clib_spinlock_trylock (p);
return 1;
}
static_always_inline void
clib_spinlock_unlock (clib_spinlock_t * p)
{
CLIB_LOCK_DBG_CLEAR (p);
/* Make sure all reads/writes are complete before releasing the lock */
clib_atomic_release (&(*p)->lock);
}
static_always_inline void
clib_spinlock_unlock_if_init (clib_spinlock_t * p)
{
if (PREDICT_FALSE (*p != 0))
clib_spinlock_unlock (p);
}
/*
* Readers-Writer Lock
*/
typedef struct clib_rw_lock_
{
CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
/* -1 when W lock held, > 0 when R lock held */
volatile i32 rw_cnt;
#if CLIB_DEBUG > 0
pid_t pid;
uword thread_index;
void *frame_address;
#endif
} *clib_rwlock_t;
always_inline void
clib_rwlock_init (clib_rwlock_t * p)
{
*p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
}
always_inline void
clib_rwlock_free (clib_rwlock_t * p)
{
if (*p)
{
clib_mem_free ((void *) *p);
*p = 0;
}
}
always_inline void
clib_rwlock_reader_lock (clib_rwlock_t * p)
{
i32 cnt;
do
{
/* rwlock held by a writer */
while ((cnt = clib_atomic_load_relax_n (&(*p)->rw_cnt)) < 0)
CLIB_PAUSE ();
}
while (!clib_atomic_cmp_and_swap_acq_relax_n
(&(*p)->rw_cnt, &cnt, cnt + 1, 1));
CLIB_LOCK_DBG (p);
}
always_inline void
clib_rwlock_reader_unlock (clib_rwlock_t * p)
{
ASSERT ((*p)->rw_cnt > 0);
CLIB_LOCK_DBG_CLEAR (p);
clib_atomic_fetch_sub_rel (&(*p)->rw_cnt, 1);
}
always_inline void
clib_rwlock_writer_lock (clib_rwlock_t * p)
{
i32 cnt = 0;
do
{
/* rwlock held by writer or reader(s) */
while ((cnt = clib_atomic_load_relax_n (&(*p)->rw_cnt)) != 0)
CLIB_PAUSE ();
}
while (!clib_atomic_cmp_and_swap_acq_relax_n (&(*p)->rw_cnt, &cnt, -1, 1));
CLIB_LOCK_DBG (p);
}
always_inline void
clib_rwlock_writer_unlock (clib_rwlock_t * p)
{
CLIB_LOCK_DBG_CLEAR (p);
clib_atomic_release (&(*p)->rw_cnt);
}
#endif
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
|
