static void set_thread_throttling(void)
{
/*
* Calculate total values across all processes.
* All numbers are per listening socket.
*/
if (max_wait_threads == 0)
max_wait_threads = MAX_WAIT_THREADS_DEFAULT * vp_count;
/* Assuming that each client session needs FD_PER_THREAD file descriptors */
if (max_threads == 0)
max_threads = (st_getfdlimit() * vp_count) / FD_PER_THREAD / sk_count;
if (max_wait_threads > max_threads)
max_wait_threads = max_threads;
/*
* Now calculate per-process values.
*/
if (max_wait_threads % vp_count)
max_wait_threads = max_wait_threads / vp_count + 1;
else
max_wait_threads = max_wait_threads / vp_count;
if (max_threads % vp_count)
max_threads = max_threads / vp_count + 1;
else
max_threads = max_threads / vp_count;
if (min_wait_threads > max_wait_threads)
min_wait_threads = max_wait_threads;
}
ST_HIDDEN int _st_epoll_init(void)
{
int fdlim;
int err = 0;
int rv = 0;
_st_epoll_data =
(struct _st_epolldata *) calloc(1, sizeof(*_st_epoll_data));
if (!_st_epoll_data)
return -1;
fdlim = st_getfdlimit();
_st_epoll_data->fd_hint = (fdlim > 0 && fdlim < ST_EPOLL_EVTLIST_SIZE) ?
fdlim : ST_EPOLL_EVTLIST_SIZE;
if ((_st_epoll_data->epfd = epoll_create(_st_epoll_data->fd_hint)) < 0) {
err = errno;
rv = -1;
goto cleanup_epoll;
}
fcntl(_st_epoll_data->epfd, F_SETFD, FD_CLOEXEC);
_st_epoll_data->pid = getpid();
/* Allocate file descriptor data array */
_st_epoll_data->fd_data_size = _st_epoll_data->fd_hint;
_st_epoll_data->fd_data =
(_epoll_fd_data_t *)calloc(_st_epoll_data->fd_data_size,
sizeof(_epoll_fd_data_t));
if (!_st_epoll_data->fd_data) {
err = errno;
rv = -1;
goto cleanup_epoll;
}
/* Allocate event lists */
_st_epoll_data->evtlist_size = _st_epoll_data->fd_hint;
_st_epoll_data->evtlist =
(struct epoll_event *)malloc(_st_epoll_data->evtlist_size *
sizeof(struct epoll_event));
if (!_st_epoll_data->evtlist) {
err = errno;
rv = -1;
}
cleanup_epoll:
if (rv < 0) {
_st_epoll_free();
_st_epoll_data = NULL;
errno = err;
}
return rv;
}
// epoll 事件源系统初始化
ST_HIDDEN int _st_epoll_init(void)
{
int fdlim;
int err = 0;
int rv = 0;
// 申请 _st_epolldata 控件
_st_epoll_data =
(struct _st_epolldata *) calloc(1, sizeof(*_st_epoll_data));
if (!_st_epoll_data)
return -1;
// 设置当前事件系统描述符限制(最大为 ST_EPOLL_EVTLIST_SIZE (4096) )
// Linux 2.6.8 内核以后该参数没有实际意义: epoll_create() creates an epoll(7) instance. Since Linux 2.6.8, the size argument is ignored, but must be greater than zero.
fdlim = st_getfdlimit();
_st_epoll_data->fd_hint = (fdlim > 0 && fdlim < ST_EPOLL_EVTLIST_SIZE) ?
fdlim : ST_EPOLL_EVTLIST_SIZE;
// 创建 epoll 描述符
if ((_st_epoll_data->epfd = epoll_create(_st_epoll_data->fd_hint)) < 0) {
err = errno;
rv = -1;
goto cleanup_epoll;
}
// 设置 FD_CLOEXEC 标致位，获取当前进程 id
fcntl(_st_epoll_data->epfd, F_SETFD, FD_CLOEXEC);
_st_epoll_data->pid = getpid();
/* Allocate file descriptor data array */
// 申请文件描述符 bucket 内存
_st_epoll_data->fd_data_size = _st_epoll_data->fd_hint;
_st_epoll_data->fd_data =
(_epoll_fd_data_t *)calloc(_st_epoll_data->fd_data_size,
sizeof(_epoll_fd_data_t));
if (!_st_epoll_data->fd_data) {
err = errno;
rv = -1;
goto cleanup_epoll;
}
/* Allocate event lists */
// 申请 epoll_event 结构内存
_st_epoll_data->evtlist_size = _st_epoll_data->fd_hint;
_st_epoll_data->evtlist =
(struct epoll_event *)malloc(_st_epoll_data->evtlist_size *
sizeof(struct epoll_event));
if (!_st_epoll_data->evtlist) {
err = errno;
rv = -1;
}
cleanup_epoll:
if (rv < 0) {
if (_st_epoll_data->epfd >= 0)
close(_st_epoll_data->epfd);
free(_st_epoll_data->fd_data);
free(_st_epoll_data->evtlist);
free(_st_epoll_data);
_st_epoll_data = NULL;
errno = err;
}
return rv;
}
