Re: [dpdk-dev] [PATCH v13 02/14] eal/linux: add rte_epoll_wait/ctl support

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2015-06-19 12:00, Cunming Liang:
> +int
> +rte_epoll_wait(int epfd, struct rte_epoll_event *events,
> +	       int maxevents, int timeout)
> +{
> +	struct epoll_event evs[maxevents];
> +	int rc;
> +
> +	if (!events) {
> +		RTE_LOG(ERR, EAL, "rte_epoll_event can't be NULL\n");
> +		return -1;
> +	}
> +
> +	/* using per thread epoll fd */
> +	if (epfd == RTE_EPOLL_PER_THREAD)
> +		epfd = rte_intr_tls_epfd();
> +
> +	while (1) {
> +		rc = epoll_wait(epfd, evs, maxevents, timeout);
> +		if (likely(rc > 0)) {
> +			/* epoll_wait has at least one fd ready to read */
> +			rc = eal_epoll_process_event(evs, rc, events);
> +			break;
> +		} else if (rc < 0) {
> +			if (errno == EINTR)
> +				continue;
> +			/* epoll_wait fail */
> +			RTE_LOG(ERR, EAL, "epoll_wait returns with fail %s\n",
> +				strerror(errno));
> +			rc = -1;
> +			break;
> +		}
> +	}
> +
> +	return rc;
> +}

In general, such loop is application-level.
What is the added value of rte_epoll_wait()?
Do we need some wrappers to libc in DPDK?