Re: [dpdk-dev] [PATCH v4 2/5] examples/multi_process: cleanup bus objects while terminating app

[David Marchand <david.marchand@redhat.com>]

On Thu, Oct 8, 2020 at 5:31 PM <rohit.raj@nxp.com> wrote:
>
> From: Rohit Raj <rohit.raj@nxp.com>
>
> Certain bus objects may need to be closed and re-acquired
> while terminating and rerunning the client application.
> Hence a signal handler is required to catch the termination
> of the App and hence closing the bus objects.
>
> This patch adds the missing signal handler in the client
> app and closes the Bus objects in both client and server
> applications when the signal Handler is called.
>
> Signed-off-by: Rohit Raj <rohit.raj@nxp.com>
> ---
>  .../multi_process/client_server_mp/mp_client/client.c | 11 +++++++++++
>  .../multi_process/client_server_mp/mp_server/main.c   |  4 +++-
>  2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/examples/multi_process/client_server_mp/mp_client/client.c b/examples/multi_process/client_server_mp/mp_client/client.c
> index 361d90b54..c37516b4c 100644
> --- a/examples/multi_process/client_server_mp/mp_client/client.c
> +++ b/examples/multi_process/client_server_mp/mp_client/client.c
> @@ -11,6 +11,7 @@
>  #include <stdlib.h>
>  #include <getopt.h>
>  #include <string.h>
> +#include <signal.h>
>
>  #include <rte_common.h>
>  #include <rte_malloc.h>
> @@ -196,6 +197,14 @@ handle_packet(struct rte_mbuf *buf)
>
>  }
>
> +static void
> +signal_handler(int signal)
> +{
> +       if (signal == SIGINT)
> +               rte_eal_cleanup();
> +       exit(0);
> +}

Calling rte_eal_cleanup from a signal handler is a bad idea.
In most cases, you are racing with other threads still using DPDK resources.
https://git.dpdk.org/dpdk/commit?id=2c434431f4
https://git.dpdk.org/dpdk/commit?id=613ce6691c

This might not be a problem in this multi_process example, but let's
keep a consistent way across all examples.
Thanks.

-- 
David Marchand