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comparison src/core/ngx_shmtx.c @ 624:d4da38525468 NGINX_1_0_2

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nginx 1.0.2 *) Feature: now shared zones and caches use POSIX semaphores. *) Bugfix: in the "rotate" parameter of the "image_filter" directive. Thanks to Adam Bocim. *) Bugfix: nginx could not be built on Solaris; the bug had appeared in 1.0.1.
author Igor Sysoev <http://sysoev.ru>
date Tue, 10 May 2011 00:00:00 +0400
parents 3dbecd747fbb
children 4d05413aebad
comparison
equal deleted inserted replaced
623:9b9e61f1b500 624:d4da38525468
14 ngx_int_t 14 ngx_int_t
15 ngx_shmtx_create(ngx_shmtx_t *mtx, void *addr, u_char *name) 15 ngx_shmtx_create(ngx_shmtx_t *mtx, void *addr, u_char *name)
16 { 16 {
17 mtx->lock = addr; 17 mtx->lock = addr;
18 18
19 if (mtx->spin == (ngx_uint_t) -1) {
20 return NGX_OK;
21 }
22
23 mtx->spin = 2048;
24
25 #if (NGX_HAVE_POSIX_SEM)
26
27 if (sem_init(&mtx->sem, 1, 0) == -1) {
28 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno,
29 "sem_init() failed");
30 } else {
31 mtx->semaphore = 1;
32 }
33
34 #endif
35
19 return NGX_OK; 36 return NGX_OK;
20 } 37 }
38
39
40 void
41 ngx_shmtx_destory(ngx_shmtx_t *mtx)
42 {
43 #if (NGX_HAVE_POSIX_SEM)
44
45 if (mtx->semaphore) {
46 if (sem_destroy(&mtx->sem) == -1) {
47 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno,
48 "sem_destroy() failed");
49 }
50 }
51
52 #endif
53 }
54
55
56 ngx_uint_t
57 ngx_shmtx_trylock(ngx_shmtx_t *mtx)
58 {
59 ngx_atomic_uint_t val;
60
61 val = *mtx->lock;
62
63 return ((val & 0x80000000) == 0
64 && ngx_atomic_cmp_set(mtx->lock, val, val | 0x80000000));
65 }
66
67
68 void
69 ngx_shmtx_lock(ngx_shmtx_t *mtx)
70 {
71 ngx_uint_t i, n;
72 ngx_atomic_uint_t val;
73
74 ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx lock");
75
76 for ( ;; ) {
77
78 val = *mtx->lock;
79
80 if ((val & 0x80000000) == 0
81 && ngx_atomic_cmp_set(mtx->lock, val, val | 0x80000000))
82 {
83 return;
84 }
85
86 if (ngx_ncpu > 1) {
87
88 for (n = 1; n < mtx->spin; n <<= 1) {
89
90 for (i = 0; i < n; i++) {
91 ngx_cpu_pause();
92 }
93
94 val = *mtx->lock;
95
96 if ((val & 0x80000000) == 0
97 && ngx_atomic_cmp_set(mtx->lock, val, val | 0x80000000))
98 {
99 return;
100 }
101 }
102 }
103
104 #if (NGX_HAVE_POSIX_SEM)
105
106 if (mtx->semaphore) {
107 val = *mtx->lock;
108
109 if ((val & 0x80000000)
110 && ngx_atomic_cmp_set(mtx->lock, val, val + 1))
111 {
112 ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
113 "shmtx wait %XA", val);
114
115 while (sem_wait(&mtx->sem) == -1) {
116 ngx_err_t err;
117
118 err = ngx_errno;
119
120 if (err != NGX_EINTR) {
121 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, err,
122 "sem_wait() failed while waiting on shmtx");
123 break;
124 }
125 }
126
127 ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
128 "shmtx awoke");
129 }
130
131 continue;
132 }
133
134 #endif
135
136 ngx_sched_yield();
137 }
138 }
139
140
141 void
142 ngx_shmtx_unlock(ngx_shmtx_t *mtx)
143 {
144 ngx_atomic_uint_t val, old, wait;
145
146 if (mtx->spin != (ngx_uint_t) -1) {
147 ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx unlock");
148 }
149
150 for ( ;; ) {
151
152 old = *mtx->lock;
153 wait = old & 0x7fffffff;
154 val = wait ? wait - 1 : 0;
155
156 if (ngx_atomic_cmp_set(mtx->lock, old, val)) {
157 break;
158 }
159 }
160
161 #if (NGX_HAVE_POSIX_SEM)
162
163 if (wait == 0 || !mtx->semaphore) {
164 return;
165 }
166
167 ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
168 "shmtx wake %XA", old);
169
170 if (sem_post(&mtx->sem) == -1) {
171 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno,
172 "sem_post() failed while wake shmtx");
173 }
174
175 #endif
176 }
177
21 178
22 #else 179 #else
23 180
24 181
25 ngx_int_t 182 ngx_int_t
63 ngx_close_file_n " \"%s\" failed", mtx->name); 220 ngx_close_file_n " \"%s\" failed", mtx->name);
64 } 221 }
65 } 222 }
66 223
67 224
68 #endif 225 ngx_uint_t
226 ngx_shmtx_trylock(ngx_shmtx_t *mtx)
227 {
228 ngx_err_t err;
229
230 err = ngx_trylock_fd(mtx->fd);
231
232 if (err == 0) {
233 return 1;
234 }
235
236 if (err == NGX_EAGAIN) {
237 return 0;
238 }
239
240 #if __osf__ /* Tru64 UNIX */
241
242 if (err == NGX_EACCESS) {
243 return 0;
244 }
245
246 #endif
247
248 ngx_log_abort(err, ngx_trylock_fd_n " %s failed", mtx->name);
249
250 return 0;
251 }
252
253
254 void
255 ngx_shmtx_lock(ngx_shmtx_t *mtx)
256 {
257 ngx_err_t err;
258
259 err = ngx_lock_fd(mtx->fd);
260
261 if (err == 0) {
262 return;
263 }
264
265 ngx_log_abort(err, ngx_lock_fd_n " %s failed", mtx->name);
266 }
267
268
269 void
270 ngx_shmtx_unlock(ngx_shmtx_t *mtx)
271 {
272 ngx_err_t err;
273
274 err = ngx_unlock_fd(mtx->fd);
275
276 if (err == 0) {
277 return;
278 }
279
280 ngx_log_abort(err, ngx_unlock_fd_n " %s failed", mtx->name);
281 }
282
283 #endif