origin nginx ngx_http_do_read_client_request_body did not limit upload rate , how did you do it ?

[ygm521]

origin nginx ngx_http_do_read_client_request_body did not limit upload rate , if in function ngx_http_do_read_client_request_body limit upload rate, the cpu is 100%， how did you do it ?
whats the meanning of xxx , thanks!

static void /* {{{ ngx_http_read_upload_client_request_body_handler */
ngx_http_read_upload_client_request_body_handler(ngx_http_request_t *r)
{
	ngx_int_t  rc;
	ngx_http_upload_ctx_t     *u = ngx_http_get_module_ctx(r, ngx_http_upload_module);
	ngx_event_t               *rev = r->connection->read;
	ngx_http_core_loc_conf_t  *clcf;

	if (rev->timedout) {
		if(!rev->delayed) {
			r->connection->timedout = 1;
			upload_shutdown_ctx(u);
			ngx_http_finalize_request(r, NGX_HTTP_REQUEST_TIME_OUT);
			return;
		}

		//xxx
		rev->timedout = 0;
		rev->delayed = 0;

		if (!rev->ready) {
			clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
			ngx_add_timer(rev, clcf->client_body_timeout);

			if (ngx_handle_read_event(rev, clcf->send_lowat) != NGX_OK) {
				upload_shutdown_ctx(u);
				ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
			}

			return;
		}
	}
	else{
		// xxx
		if (r->connection->read->delayed) {
			clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
			ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0,
						   "http read delayed");

			if (ngx_handle_read_event(rev, clcf->send_lowat) != NGX_OK) {
				upload_shutdown_ctx(u);
				ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
			}

			return;
		}
	}

	//读取请求的包体
	rc = ngx_http_do_read_upload_client_request_body(r);

	if (rc >= NGX_HTTP_SPECIAL_RESPONSE) {
		upload_shutdown_ctx(u);
		ngx_http_finalize_request(r, rc);
	}
} /* }}} */