Re: [dpdk-dev] [PATCH v2 2/3] examples/l2fwd: Handle SIGINT and SIGTERM in l2fwd

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 24 Dec 2015 21:37:11 -0500
Zhihong Wang <zhihong.wang@intel.com> wrote:

> Handle SIGINT and SIGTERM in l2fwd.
> 
> Signed-off-by: Zhihong Wang <zhihong.wang@intel.com>
> ---
>  examples/l2fwd/main.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
> 
> diff --git a/examples/l2fwd/main.c b/examples/l2fwd/main.c
> index 720fd5a..75899dd 100644
> --- a/examples/l2fwd/main.c
> +++ b/examples/l2fwd/main.c
> @@ -44,6 +44,8 @@
>  #include <ctype.h>
>  #include <errno.h>
>  #include <getopt.h>
> +#include <signal.h>
> +#include <unistd.h>
>  
>  #include <rte_common.h>
>  #include <rte_log.h>
> @@ -69,6 +71,9 @@
>  #include <rte_mempool.h>
>  #include <rte_mbuf.h>
>  
> +static int force_quit = -1;
> +static int signo_quit = -1;

These need to be volatile otherwise you risk compiler optimizing
away your checks.

Also, don't use -1/0 just use 0/1 for boolean or better yet
the definition in <stdbool.h> of bool and true/false.
That way the code can read much nicer.

>  #define RTE_LOGTYPE_L2FWD RTE_LOGTYPE_USER1
>  
>  #define NB_MBUF   8192
> @@ -284,6 +289,8 @@ l2fwd_main_loop(void)
>  	}
>  
>  	while (1) {
> +		if (unlikely(force_quit != 0))
> +			break;

Please maske this a proper while loop instead.

        while (!force_quit) {

>  
>  		cur_tsc = rte_rdtsc();
>  
> @@ -534,6 +541,45 @@ check_all_ports_link_status(uint8_t port_num, uint32_t port_mask)
>  	}
>  }
>  
> +static void
> +stop_ports(void)
> +{
> +	unsigned portid, nb_ports;
> +
> +	nb_ports = rte_eth_dev_count();
> +	for (portid = 0; portid < nb_ports; portid++) {
> +		if ((l2fwd_enabled_port_mask & (1 << portid)) == 0) {
> +			continue;
> +		}

No need for {} here.

> +		printf("Stopping port %d...", portid);
> +		rte_eth_dev_stop(portid);
> +		rte_eth_dev_close(portid);
> +		printf(" Done\n");
> +	}
> +}
> +
> +static void
> +signal_handler(__rte_unused int signum)
> +{
> +	if (signum == SIGINT || signum == SIGTERM) {

signum is used, dont give __rte_unused attribute.

>  
>  	/* launch per-lcore init on every lcore */
> +	force_quit = 0;

What is gained by having tri-value here. Just initialize it as false.


>  	rte_eal_mp_remote_launch(l2fwd_launch_one_lcore, NULL, CALL_MASTER);
>  	RTE_LCORE_FOREACH_SLAVE(lcore_id) {
>  		if (rte_eal_wait_lcore(lcore_id) < 0)
>  			return -1;
>  	}
>  
> +	printf("Stopping forwarding... Done\n");
> +	/* stop ports */
> +	stop_ports();
> +	printf("Bye...\n");
> +	/* inform if there's a caller */
> +	if (force_quit != 0) {
> +		signal(signo_quit, SIG_DFL);
> +		kill(getpid(), signo_quit);

The kill should not be needed.

It would be good if examples cleaned up allocations, that way they
could be used with valgrind for validation of drivers, etc.