> -----Original Message-----
> From: Burakov, Anatoly
> Sent: Tuesday, February 27, 2018 10:36 PM
> To: dev@dpdk.org
> Cc: Tan, Jianfeng
> Subject: [PATCH v3 2/5] eal: don't process IPC messages before init finished
>
> It is not possible for a primary process to receive any messages
> while initializing, because RTE_MAGIC value is not set in the
> shared config, and hence no secondary process can ever spin up
> during that time.
>
> However, it is possible for a secondary process to receive messages
> from the primary during initialization. We can't just drop the
> messages as they may be important, and also we might need to process
> replies to our own requests (e.g. VFIO) during initialization.
>
> Therefore, add a tailq for incoming messages, and queue them up
> until initialization is complete, and process them in order they
> arrived.
>
> Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com>
> ---
>
> Notes:
> v3: check for init_complete after receiving message
>
> v2: no changes
>
> lib/librte_eal/common/eal_common_proc.c | 52
> +++++++++++++++++++++++++++++----
> 1 file changed, 47 insertions(+), 5 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_proc.c
> b/lib/librte_eal/common/eal_common_proc.c
> index 3a1088e..a6e24e6 100644
> --- a/lib/librte_eal/common/eal_common_proc.c
> +++ b/lib/librte_eal/common/eal_common_proc.c
> @@ -25,6 +25,7 @@
> #include <rte_errno.h>
> #include <rte_lcore.h>
> #include <rte_log.h>
> +#include <rte_tailq.h>
>
> #include "eal_private.h"
> #include "eal_filesystem.h"
> @@ -58,6 +59,18 @@ struct mp_msg_internal {
> struct rte_mp_msg msg;
> };
>
> +struct message_queue_entry {
> + TAILQ_ENTRY(message_queue_entry) next;
> + struct mp_msg_internal msg;
> + struct sockaddr_un sa;
> +};
> +
> +/** Double linked list of received messages. */
> +TAILQ_HEAD(message_queue, message_queue_entry);
> +
> +static struct message_queue message_queue =
> + TAILQ_HEAD_INITIALIZER(message_queue);
> +
> struct sync_request {
> TAILQ_ENTRY(sync_request) next;
> int reply_received;
> @@ -276,12 +289,41 @@ process_msg(struct mp_msg_internal *m, struct
> sockaddr_un *s)
> static void *
> mp_handle(void *arg __rte_unused)
> {
> - struct mp_msg_internal msg;
> - struct sockaddr_un sa;
> -
> + struct message_queue_entry *cur_msg, *next_msg, *new_msg =
> NULL;
> while (1) {
> - if (read_msg(&msg, &sa) == 0)
> - process_msg(&msg, &sa);
> + /* we want to process all messages in order of their arrival,
> + * but status of init_complete may change while we're
> iterating
> + * the tailq. so, store it here and check once every iteration.
> + */
> + int init_complete;
> +
> + if (new_msg == NULL)
> + new_msg = malloc(sizeof(*new_msg));
> + if (read_msg(&new_msg->msg, &new_msg->sa) == 0) {
Suppose a case that: req and msg received but init not completed, so we enqueue
all of them in the tailq; and from now on, no req/rep/msg comes. Then mp thread
will hang here for reading new message.
In such a case, we might need the master thread to signal mp thread to wake up
when init is completed?
Thanks,
Jianfeng
> + /* we successfully read the message, so enqueue it
> */
> + TAILQ_INSERT_TAIL(&message_queue, new_msg,
> next);
> + new_msg = NULL;
> + } /* reuse new_msg for next message if we couldn't
> read_msg */
> +
> + init_complete = internal_config.init_complete;
> +
> + /* tailq only accessed here, so no locking needed */
> + TAILQ_FOREACH_SAFE(cur_msg, &message_queue, next,
> next_msg) {
> + /* secondary process should not process any
> incoming
> + * requests until its initialization is complete, but
> + * it is allowed to process replies to its own queries.
> + */
> + if (rte_eal_process_type() ==
> RTE_PROC_SECONDARY &&
> + !init_complete &&
> + cur_msg->msg.type != MP_REP)
> + continue;
> +
> + TAILQ_REMOVE(&message_queue, cur_msg, next);
> +
> + process_msg(&cur_msg->msg, &cur_msg->sa);
> +
> + free(cur_msg);
> + }
> }
>
> return NULL;
> --
> 2.7.4
