do_epoll_op
do_epoll_op(w, op, fd);
do_epoll_op(w, OP_EPOLL_ADD, w->fdmap[i]);
do_epoll_op(w, OP_EPOLL_MOD, w->fdmap[i]);
do_epoll_op(w, OP_EPOLL_DEL, w->fdmap[i]);