Limit the request rate for one URL in nginx

# 10 MB of state holds roughly 160,000 addresses
limit_req_zone $binary_remote_addr zone=login:10m rate=5r/m;

server {
    location = /wp-login.php {
        limit_req        zone=login burst=3 nodelay;
        limit_req_status 429;

        include      fastcgi_params;
        fastcgi_pass unix:/var/run/php5-fpm.sock;
    }
}