Re: [dpdk-dev] [PATCH v2 2/4] eal: add and del secondary processes in the primary

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

> -----Original Message-----
> From: Tan, Jianfeng
> Sent: Thursday, January 11, 2018 4:08 AM
> To: dev@dpdk.org
> Cc: Burakov, Anatoly <anatoly.burakov@intel.com>; Richardson, Bruce <bruce.richardson@intel.com>; Ananyev, Konstantin
> <konstantin.ananyev@intel.com>; thomas@monjalon.net; Tan, Jianfeng <jianfeng.tan@intel.com>
> Subject: [PATCH v2 2/4] eal: add and del secondary processes in the primary
> 
> By the multi-process channel, we add an mp action named "proc".
> 
> As a secondary process starts, it sends a "proc add" message to
> the primary.
> 
> As the primary finds a failure in sending message to a specific
> secondary process, that secondary process is treated as exited;
> and we remove it from the secondary array by sending a "proc del"
> message to the primary itself.
> 
> Test:
>   1. Start the primary and the secondary process
>     $ (testpmd) -c 0x3 -n 4 -- -i
>     $ (helloworld) -c 0xc -n 4 --proc-type=auto --
> 
>   2. Check the log of testpmd:
>     ...
>     EAL: bind to /var/run/.rte_unix
>     ...
>     EAL: add secondary: /var/run/.testpmd_unix_(xxx)
>     ...
> 
>   3. Check the log of helloworld:
>     ...
>     EAL: bind to /var/run/.testpmd_unix_xxx
>     EAL: bind to /var/run/.testpmd_unix_c_xxx
>     ...
> 
> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
> ---
>  lib/librte_eal/common/eal_common_proc.c | 88 ++++++++++++++++++++++++++++++++-
>  1 file changed, 86 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_eal/common/eal_common_proc.c b/lib/librte_eal/common/eal_common_proc.c
> index d700e9e..70519cc 100644
> --- a/lib/librte_eal/common/eal_common_proc.c
> +++ b/lib/librte_eal/common/eal_common_proc.c
> @@ -54,6 +54,13 @@ struct mp_msghdr {
>  	char params[0];
>  } __rte_packed;
> 
> +struct proc_request {
> +#define MP_PROC_ADD	0
> +#define MP_PROC_DEL	1
> +	int type;
> +	char path[MAX_UNIX_PATH_LEN];
> +};
> +
>  int
>  rte_eal_primary_proc_alive(const char *config_file_path)
>  {
> @@ -214,6 +221,58 @@ mp_handle(void *arg __rte_unused)
>  	return NULL;
>  }
> 
> +static int
> +add_sec_proc(const char *path)
> +{
> +	int i;
> +
> +	for (i = 0; i < MAX_SECONDARY_PROCS; ++i)
> +		if (mp_sec_sockets[i] == NULL)
> +			break;
> +	if (i < MAX_SECONDARY_PROCS)
> +		mp_sec_sockets[i] = strdup(path);
> +
> +	return i < MAX_SECONDARY_PROCS;
> +}
> +
> +static int
> +del_sec_proc(const char *path)
> +{
> +	int i;
> +
> +	for (i = 0; i < MAX_SECONDARY_PROCS; ++i) {
> +		if (!strcmp(mp_sec_sockets[i], path)) {
> +			free(mp_sec_sockets[i]);
> +			mp_sec_sockets[i] = NULL;
> +			break;
> +		}
> +	}
> +
> +	return i < MAX_SECONDARY_PROCS;
> +}


I am not sure we really need all these add/del messages and mp_sec_sockets[]...
For broadcast - why we can't just scan contents of our home dir for all open client sockets
and send a message to each such socket found.
Konstantin

> +
> +static int
> +mp_primary_proc(const void *params,
> +		int len __rte_unused,
> +		int fds[] __rte_unused,
> +		int fds_num __rte_unused)
> +{
> +	const struct proc_request *r = (const struct proc_request *)params;
> +
> +	switch (r->type) {
> +	case MP_PROC_ADD:
> +		RTE_LOG(INFO, EAL, "add secondary: %s\n", r->path);
> +		return add_sec_proc(r->path);
> +	case MP_PROC_DEL:
> +		RTE_LOG(INFO, EAL, "del secondary: %s\n", r->path);
> +		return del_sec_proc(r->path);
> +	default:
> +		RTE_LOG(ERR, EAL, "invalid type: %d\n", r->type);
> +	}
> +
> +	return -1;
> +}
> +
>  static inline const char *
>  get_unix_path(int is_server)
>  {
> @@ -267,6 +326,22 @@ rte_eal_mp_channel_init(void)
>  	if (mp_fd < 0)
>  		return -1;
> 
> +	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
> +		if (rte_eal_mp_action_register("proc", mp_primary_proc) < 0) {
> +			RTE_LOG(ERR, EAL, "failed to register handler\n");
> +			goto error;
> +		}
> +	} else {
> +		struct proc_request r;
> +
> +		r.type = MP_PROC_ADD;
> +		snprintf(r.path, MAX_UNIX_PATH_LEN, "%s", get_unix_path(1));
> +		if (rte_eal_mp_sendmsg("proc", &r, sizeof(r), NULL, 0) < 0) {
> +			RTE_LOG(ERR, EAL, "failed to add into primary\n");
> +			goto error;
> +		}
> +	}
> +
>  	if (pthread_create(&tid, NULL, mp_handle, NULL) < 0) {
>  		RTE_LOG(ERR, EAL, "failed to create mp handle thead: %s\n",
>  			strerror(errno));
> @@ -354,10 +429,19 @@ send_msg(int fd, const char *dst_path, struct mp_msghdr *msg, int fds[])
>  	if (ret < 0) {
>  		RTE_LOG(ERR, EAL, "failed to send msg: %s\n", strerror(errno));
> 
> -		if (rte_eal_process_type() == RTE_PROC_PRIMARY)
> +		if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
> +			struct proc_request r;
> +
>  			RTE_LOG(ERR, EAL, "secondary process (%s) exited\n",
>  				dst_path);
> -		else if (!rte_eal_primary_proc_alive(NULL))
> +			r.type = MP_PROC_DEL;
> +			snprintf(r.path, MAX_UNIX_PATH_LEN, "%s", dst_path);
> +			if (rte_eal_mp_sendmsg("proc", &r,
> +						sizeof(r), NULL, 0) < 0)
> +				RTE_LOG(ERR, EAL,
> +					"failed to del secondary %s\n",
> +					dst_path);
> +		} else if (!rte_eal_primary_proc_alive(NULL))
>  			RTE_LOG(ERR, EAL, "primary process exited\n");
> 
>  		return 0;
> --
> 2.7.4