Upstream keepalive: keepalive_requests directive. The directive configures maximum number of requests allowed on a connection kept in the cache. Once a connection reaches the number of requests configured, it is no longer saved to the cache. The default is 100. Much like keepalive_requests for client connections, this is mostly a safeguard to make sure connections are closed periodically and the memory allocated from the connection pool is freed.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


int
ngx_nonblocking(ngx_socket_t s)
{
    unsigned long  nb = 1;

    return ioctlsocket(s, FIONBIO, &nb);
}


int
ngx_blocking(ngx_socket_t s)
{
    unsigned long  nb = 0;

    return ioctlsocket(s, FIONBIO, &nb);
}


int
ngx_tcp_push(ngx_socket_t s)
{
    return 0;
}