0
|
1
|
|
2 /*
|
|
3 * Copyright (C) Igor Sysoev
|
|
4 */
|
|
5
|
|
6
|
|
7 #include <ngx_config.h>
|
|
8 #include <ngx_core.h>
|
|
9
|
|
10
|
42
|
11 /*
|
|
12 * TODO: the P4 optimized assembler version with the "pause" operation
|
|
13 */
|
|
14
|
0
|
15 void ngx_spinlock(ngx_atomic_t *lock, ngx_uint_t spin)
|
|
16 {
|
|
17
|
|
18 #if (NGX_HAVE_ATOMIC_OPS)
|
|
19
|
|
20 ngx_uint_t tries;
|
|
21
|
|
22 tries = 0;
|
|
23
|
|
24 for ( ;; ) {
|
|
25
|
|
26 if (*lock) {
|
|
27 if (ngx_ncpu > 1 && tries++ < spin) {
|
|
28 continue;
|
|
29 }
|
|
30
|
|
31 ngx_sched_yield();
|
|
32
|
|
33 tries = 0;
|
|
34
|
|
35 } else {
|
|
36 if (ngx_atomic_cmp_set(lock, 0, 1)) {
|
|
37 return;
|
|
38 }
|
|
39 }
|
|
40 }
|
|
41
|
|
42 #else
|
|
43
|
|
44 #if (NGX_THREADS)
|
|
45
|
|
46 #error ngx_spinlock() or ngx_atomic_cmp_set() are not defined !
|
|
47
|
|
48 #endif
|
|
49
|
|
50 #endif
|
|
51
|
|
52 }
|