Some comments.
The title does not reflect the observed issue.
I understand that secondary processeses can't be started from a docker
container.
The patch title should reflect this.
On Wed, Jul 24, 2019 at 10:20 AM <yasufu...@gmail.com> wrote:
>
> From: Yasufumi Ogawa <ogawa.yasuf...@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 secondary is run as app container because each of
> containerized secondary has PID 1. To reserve unique name, use hostname
> instead of PID because hostname is assigned as a short form of 64
> digits full container ID in docker.
>
> Cc: sta...@dpdk.org
I don't think we want to backport this behavior change.
>
> Signed-off-by: Yasufumi Ogawa <ogawa.yasuf...@lab.ntt.co.jp>
> ---
> lib/librte_eal/linux/eal/eal_memalloc.c | 28 +++++++++++++++++++++++--
> 1 file changed, 26 insertions(+), 2 deletions(-)
>
> diff --git a/lib/librte_eal/linux/eal/eal_memalloc.c
> b/lib/librte_eal/linux/eal/eal_memalloc.c
> index 1f6a7c18f..356b304a8 100644
> --- a/lib/librte_eal/linux/eal/eal_memalloc.c
> +++ b/lib/librte_eal/linux/eal/eal_memalloc.c
> @@ -1366,6 +1366,7 @@ 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[33] = { 0 }; /* 32bytes is enough if using hostname */
This variable only makes sense in the if (getpid() == 1) branch,
please move it there, and see below comment about using gethostname().
>
> if (msl->external)
> return 0;
> @@ -1375,8 +1376,31 @@ 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.
> + * In docker, hostname is assigned as a short form of full container
> + * ID. So use hostname as unique ID among containers instead.
I understand this is how it works for docker.
Is this the same in other container environments?
> + */
> + if (getpid() == 1) {
> + FILE *hn_fp;
> + hn_fp = fopen("/etc/hostname", "r");
Why not use gethostname() ?
Plus, this api defines the maximum size of the hostname as HOST_NAME_MAX bytes.
> + if (hn_fp == NULL) {
> + RTE_LOG(ERR, EAL,
> + "Cannot open '/etc/hostname' for
> secondary\n");
> + return -1;
> + }
> +
> + /* with docker, /etc/hostname just has one entry of hostname
> */
> + if (fscanf(hn_fp, "%32s", proc_id) == EOF) {
> + fclose(hn_fp);
> + return -1;
> + }
> + fclose(hn_fp);
> + } 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
>
--
David Marchand
