Re: [dpdk-dev] [PATCH v5 1/1] fbarray: fix duplicated fbarray file in secondary

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of yasufum.o@gmail.com
> Sent: Monday, October 28, 2019 8:08 AM
> To: Burakov, Anatoly <anatoly.burakov@intel.com>; david.marchand@redhat.com
> Cc: dev@dpdk.org; stable@dpdk.org; yasufum.o@gmail.com; Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>
> Subject: [dpdk-dev] [PATCH v5 1/1] fbarray: fix duplicated fbarray file in secondary
> 
> From: Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>
> 
> In secondary_msl_create_walk(), it creates a file for fbarrays with its
> PID for reserving unique name among secondary processes. However, it
> does not work if several secondaries run as app containers because each
> of containerized secondary has PID 1, and failed to reserve unique name
> other than first one. To reserve unique name in each of containers, use
> hostname instead of PID only if PID is 1.
> 
> Cc: stable@dpdk.org
> 
> Signed-off-by: Yasufumi Ogawa <yasufum.o@gmail.com>
> ---
>  lib/librte_eal/linux/eal/eal_memalloc.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_eal/linux/eal/eal_memalloc.c b/lib/librte_eal/linux/eal/eal_memalloc.c
> index af6d0d023..699079791 100644
> --- a/lib/librte_eal/linux/eal/eal_memalloc.c
> +++ b/lib/librte_eal/linux/eal/eal_memalloc.c
> @@ -1365,6 +1365,7 @@ secondary_msl_create_walk(const struct rte_memseg_list *msl,
>  	struct rte_memseg_list *primary_msl, *local_msl;
>  	char name[PATH_MAX];
>  	int msl_idx, ret;
> +	char proc_id[HOST_NAME_MAX] = { 0 };
> 
>  	if (msl->external)
>  		return 0;
> @@ -1374,8 +1375,18 @@ secondary_msl_create_walk(const struct rte_memseg_list *msl,
>  	local_msl = &local_memsegs[msl_idx];
> 
>  	/* create distinct fbarrays for each secondary */
> -	snprintf(name, RTE_FBARRAY_NAME_LEN, "%s_%i",
> -		primary_msl->memseg_arr.name, getpid());
> +	/* If run secondary in a container, the name of fbarray file should
> +	 * not be decided with pid because getpid() always returns 1.


I wonder why is that?
What will prevent user to do something like:
docker run -it --cpuset-cpus=7-8 -v /local/kananye1:/local/kananye1 ubuntu-dpdk-local:latest /bin/bash
And then start dpdk app manually within the container?
 
> +	 * In docker, hostname is assigned as a short form of full container
> +	 * ID. So use hostname as unique ID among containers instead.
> +	 */
> +	if (getpid() == 1)
> +		gethostname(proc_id, HOST_NAME_MAX);
> +	else
> +		sprintf(proc_id, "%d", (int)getpid());
> +
> +	snprintf(name, RTE_FBARRAY_NAME_LEN, "%s_%s",
> +			primary_msl->memseg_arr.name, proc_id);
> 
>  	ret = rte_fbarray_init(&local_msl->memseg_arr, name,
>  		primary_msl->memseg_arr.len,
> --
> 2.17.1