ngx_os_init解析

 1 ngx_int_t
 2 ngx_os_init(ngx_log_t *log)
 3 {
 4     ngx_time_t  *tp;
 5     ngx_uint_t   n;
 6 #if (NGX_HAVE_LEVEL1_DCACHE_LINESIZE)
 7     long         size;
 8 #endif
 9 
10 #if (NGX_HAVE_OS_SPECIFIC_INIT)
11     // 初始化linux内核版本号
12     if (ngx_os_specific_init(log) != NGX_OK) {
13         return NGX_ERROR;
14     }
15 #endif
16     // 初始化proctitle内存空间
17     if (ngx_init_setproctitle(log) != NGX_OK) {
18         return NGX_ERROR;
19     }
20 
21     // 获取page size
22     ngx_pagesize = getpagesize();
23     // 获取cacheline size
24     ngx_cacheline_size = NGX_CPU_CACHE_LINE;
25 
26     // 2 ^ ngx_pagesize_shift == ngx_page_size
27     for (n = ngx_pagesize; n >>= 1; ngx_pagesize_shift++) { /* void */ }
28 
29 #if (NGX_HAVE_SC_NPROCESSORS_ONLN)
30     if (ngx_ncpu == 0) {
31         // 获取CPU核数
32         ngx_ncpu = sysconf(_SC_NPROCESSORS_ONLN);
33     }
34 #endif
35 
36     if (ngx_ncpu < 1) {
37         ngx_ncpu = 1;
38     }
39 
40 #if (NGX_HAVE_LEVEL1_DCACHE_LINESIZE)
41     //获取1-cache line size
42     size = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
43     if (size > 0) {
44         ngx_cacheline_size = size;
45     }
46 #endif
47 
48     // 根据CPU info获取cacheline size
49     ngx_cpuinfo();
50 
51     //获取打开最多文件数
52     if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
53         ngx_log_error(NGX_LOG_ALERT, log, errno,
54                       "getrlimit(RLIMIT_NOFILE) failed");
55         return NGX_ERROR;
56     }
57 
58     ngx_max_sockets = (ngx_int_t) rlmt.rlim_cur;
59 
60 #if (NGX_HAVE_INHERITED_NONBLOCK || NGX_HAVE_ACCEPT4)
61     ngx_inherited_nonblocking = 1;
62 #else
63     ngx_inherited_nonblocking = 0;
64 #endif
65 
66     tp = ngx_timeofday();
67     //初始化rand种子
68     srandom(((unsigned) ngx_pid << 16) ^ tp->sec ^ tp->msec);
69 
70     return NGX_OK;
71 }