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
221
222
223
224
|
/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2015 Intel Corporation
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <stddef.h>
#include <limits.h>
#include <inttypes.h>
#include <unistd.h>
#include <pthread.h>
#include <fcntl.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <rte_per_lcore.h>
#include <rte_log.h>
#include <rte_spinlock.h>
#include <rte_common.h>
#include "lthread_api.h"
#include "lthread_int.h"
#include "lthread_mutex.h"
#include "lthread_sched.h"
#include "lthread_queue.h"
#include "lthread_objcache.h"
#include "lthread_diag.h"
/*
* Create a mutex
*/
int
lthread_mutex_init(char *name, struct lthread_mutex **mutex,
__rte_unused const struct lthread_mutexattr *attr)
{
struct lthread_mutex *m;
if (mutex == NULL)
return POSIX_ERRNO(EINVAL);
m = _lthread_objcache_alloc((THIS_SCHED)->mutex_cache);
if (m == NULL)
return POSIX_ERRNO(EAGAIN);
m->blocked = _lthread_queue_create("blocked queue");
if (m->blocked == NULL) {
_lthread_objcache_free((THIS_SCHED)->mutex_cache, m);
return POSIX_ERRNO(EAGAIN);
}
if (name == NULL)
strncpy(m->name, "no name", sizeof(m->name));
else
strncpy(m->name, name, sizeof(m->name));
m->name[sizeof(m->name)-1] = 0;
m->root_sched = THIS_SCHED;
m->owner = NULL;
rte_atomic64_init(&m->count);
DIAG_CREATE_EVENT(m, LT_DIAG_MUTEX_CREATE);
/* success */
(*mutex) = m;
return 0;
}
/*
* Destroy a mutex
*/
int lthread_mutex_destroy(struct lthread_mutex *m)
{
if ((m == NULL) || (m->blocked == NULL)) {
DIAG_EVENT(m, LT_DIAG_MUTEX_DESTROY, m, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
if (m->owner == NULL) {
/* try to delete the blocked queue */
if (_lthread_queue_destroy(m->blocked) < 0) {
DIAG_EVENT(m, LT_DIAG_MUTEX_DESTROY,
m, POSIX_ERRNO(EBUSY));
return POSIX_ERRNO(EBUSY);
}
/* free the mutex to cache */
_lthread_objcache_free(m->root_sched->mutex_cache, m);
DIAG_EVENT(m, LT_DIAG_MUTEX_DESTROY, m, 0);
return 0;
}
/* can't do its still in use */
DIAG_EVENT(m, LT_DIAG_MUTEX_DESTROY, m, POSIX_ERRNO(EBUSY));
return POSIX_ERRNO(EBUSY);
}
/*
* Try to obtain a mutex
*/
int lthread_mutex_lock(struct lthread_mutex *m)
{
struct lthread *lt = THIS_LTHREAD;
if ((m == NULL) || (m->blocked == NULL)) {
DIAG_EVENT(m, LT_DIAG_MUTEX_LOCK, m, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
/* allow no recursion */
if (m->owner == lt) {
DIAG_EVENT(m, LT_DIAG_MUTEX_LOCK, m, POSIX_ERRNO(EDEADLK));
return POSIX_ERRNO(EDEADLK);
}
for (;;) {
rte_atomic64_inc(&m->count);
do {
if (rte_atomic64_cmpset
((uint64_t *) &m->owner, 0, (uint64_t) lt)) {
/* happy days, we got the lock */
DIAG_EVENT(m, LT_DIAG_MUTEX_LOCK, m, 0);
return 0;
}
/* spin due to race with unlock when
* nothing was blocked
*/
} while ((rte_atomic64_read(&m->count) == 1) &&
(m->owner == NULL));
/* queue the current thread in the blocked queue
* we defer this to after we return to the scheduler
* to ensure that the current thread context is saved
* before unlock could result in it being dequeued and
* resumed
*/
DIAG_EVENT(m, LT_DIAG_MUTEX_BLOCKED, m, lt);
lt->pending_wr_queue = m->blocked;
/* now relinquish cpu */
_suspend();
/* resumed, must loop and compete for the lock again */
}
return 0;
}
/* try to lock a mutex but don't block */
int lthread_mutex_trylock(struct lthread_mutex *m)
{
struct lthread *lt = THIS_LTHREAD;
if ((m == NULL) || (m->blocked == NULL)) {
DIAG_EVENT(m, LT_DIAG_MUTEX_TRYLOCK, m, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
if (m->owner == lt) {
/* no recursion */
DIAG_EVENT(m, LT_DIAG_MUTEX_TRYLOCK, m, POSIX_ERRNO(EDEADLK));
return POSIX_ERRNO(EDEADLK);
}
rte_atomic64_inc(&m->count);
if (rte_atomic64_cmpset
((uint64_t *) &m->owner, (uint64_t) NULL, (uint64_t) lt)) {
/* got the lock */
DIAG_EVENT(m, LT_DIAG_MUTEX_TRYLOCK, m, 0);
return 0;
}
/* failed so return busy */
rte_atomic64_dec(&m->count);
DIAG_EVENT(m, LT_DIAG_MUTEX_TRYLOCK, m, POSIX_ERRNO(EBUSY));
return POSIX_ERRNO(EBUSY);
}
/*
* Unlock a mutex
*/
int lthread_mutex_unlock(struct lthread_mutex *m)
{
struct lthread *lt = THIS_LTHREAD;
struct lthread *unblocked;
if ((m == NULL) || (m->blocked == NULL)) {
DIAG_EVENT(m, LT_DIAG_MUTEX_UNLOCKED, m, POSIX_ERRNO(EINVAL));
return POSIX_ERRNO(EINVAL);
}
/* fail if its owned */
if (m->owner != lt || m->owner == NULL) {
DIAG_EVENT(m, LT_DIAG_MUTEX_UNLOCKED, m, POSIX_ERRNO(EPERM));
return POSIX_ERRNO(EPERM);
}
rte_atomic64_dec(&m->count);
/* if there are blocked threads then make one ready */
while (rte_atomic64_read(&m->count) > 0) {
unblocked = _lthread_queue_remove(m->blocked);
if (unblocked != NULL) {
rte_atomic64_dec(&m->count);
DIAG_EVENT(m, LT_DIAG_MUTEX_UNLOCKED, m, unblocked);
RTE_ASSERT(unblocked->sched != NULL);
_ready_queue_insert((struct lthread_sched *)
unblocked->sched, unblocked);
break;
}
}
/* release the lock */
m->owner = NULL;
return 0;
}
/*
* return the diagnostic ref val stored in a mutex
*/
uint64_t
lthread_mutex_diag_ref(struct lthread_mutex *m)
{
if (m == NULL)
return 0;
return m->diag_ref;
}
|
