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eal: add synchronous multi-process communication

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We need the synchronous way for multi-process communication,
i.e., blockingly waiting for reply message when we send a request
to the peer process.

We add two APIs rte_eal_mp_request() and rte_eal_mp_reply() for
such use case. By invoking rte_eal_mp_request(), a request message
is sent out, and then it waits there for a reply message. The caller
can specify the timeout. And the response messages will be collected
and returned so that the caller can decide how to translate them.

The API rte_eal_mp_reply() is always called by an mp action handler.
Here we add another parameter for rte_eal_mp_t so that the action
handler knows which peer address to reply.

       sender-process                receiver-process
   ----------------------            ----------------

    thread-n
     |_rte_eal_mp_request() ----------> mp-thread
        |_timedwait()                    |_process_msg()
                                           |_action()
                                               |_rte_eal_mp_reply()
	        mp_thread  <---------------------|
                  |_process_msg()
                     |_signal(send_thread)
    thread-m <----------|
     |_collect-reply

 * A secondary process is only allowed to talk to the primary process.
 * If there are multiple secondary processes for the primary process,
   it will send request to peer1, collect response from peer1; then
   send request to peer2, collect response from peer2, and so on.
 * When thread-n is sending request, thread-m of that process can send
   request at the same time.
 * For pair <action_name, peer>, we guarantee that only one such request
   is on the fly.

Suggested-by: Anatoly Burakov <anatoly.burakov@intel.com>
Suggested-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
This commit is contained in:
Jianfeng Tan 2018-01-30 06:58:09 +00:00 committed by Thomas Monjalon
parent bacaa27540
commit 783b6e5497
4 changed files with 298 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
doc/guides/rel_notes/release_18_02.rst
View File

@ -175,6 +175,8 @@ New Features
* ``rte_mp_register`` and ``rte_mp_unregister`` are for action (un)registration.
* ``rte_mp_sendmsg`` is for sending a message without blocking for a response.
* ``rte_mp_request`` is for sending a request message and will block until
it gets a reply message which is sent from the peer by ``rte_mp_reply``.
API Changes
-----------

254
lib/librte_eal/common/eal_common_proc.c
View File

@ -13,6 +13,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
@ -46,6 +47,50 @@ TAILQ_HEAD(action_entry_list, action_entry);
static struct action_entry_list action_entry_list =
TAILQ_HEAD_INITIALIZER(action_entry_list);
enum mp_type {
MP_MSG, /* Share message with peers, will not block */
MP_REQ, /* Request for information, Will block for a reply */
MP_REP, /* Response to previously-received request */
};
struct mp_msg_internal {
int type;
struct rte_mp_msg msg;
};
struct sync_request {
TAILQ_ENTRY(sync_request) next;
int reply_received;
char dst[PATH_MAX];
struct rte_mp_msg *request;
struct rte_mp_msg *reply;
pthread_cond_t cond;
};
TAILQ_HEAD(sync_request_list, sync_request);
static struct {
struct sync_request_list requests;
pthread_mutex_t lock;
} sync_requests = {
.requests = TAILQ_HEAD_INITIALIZER(sync_requests.requests),
.lock = PTHREAD_MUTEX_INITIALIZER
};
static struct sync_request *
find_sync_request(const char *dst, const char *act_name)
{
struct sync_request *r;
TAILQ_FOREACH(r, &sync_requests.requests, next) {
if (!strcmp(r->dst, dst) &&
!strcmp(r->request->name, act_name))
break;
}
return r;
}
int
rte_eal_primary_proc_alive(const char *config_file_path)
{
@ -149,19 +194,21 @@ rte_mp_action_unregister(const char *name)
}
static int
read_msg(struct rte_mp_msg *msg)
read_msg(struct mp_msg_internal *m, struct sockaddr_un *s)
{
int msglen;
struct iovec iov;
struct msghdr msgh;
char control[CMSG_SPACE(sizeof(msg->fds))];
char control[CMSG_SPACE(sizeof(m->msg.fds))];
struct cmsghdr *cmsg;
int buflen = sizeof(*msg) - sizeof(msg->fds);
int buflen = sizeof(*m) - sizeof(m->msg.fds);
memset(&msgh, 0, sizeof(msgh));
iov.iov_base = msg;
iov.iov_base = m;
iov.iov_len = buflen;
msgh.msg_name = s;
msgh.msg_namelen = sizeof(*s);
msgh.msg_iov = &iov;
msgh.msg_iovlen = 1;
msgh.msg_control = control;
@ -183,7 +230,7 @@ read_msg(struct rte_mp_msg *msg)
cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
if ((cmsg->cmsg_level == SOL_SOCKET) &&
(cmsg->cmsg_type == SCM_RIGHTS)) {
memcpy(msg->fds, CMSG_DATA(cmsg), sizeof(msg->fds));
memcpy(m->msg.fds, CMSG_DATA(cmsg), sizeof(m->msg.fds));
break;
}
}
@ -192,12 +239,28 @@ read_msg(struct rte_mp_msg *msg)
}
static void
process_msg(struct rte_mp_msg *msg)
process_msg(struct mp_msg_internal *m, struct sockaddr_un *s)
{
struct sync_request *sync_req;
struct action_entry *entry;
struct rte_mp_msg *msg = &m->msg;
rte_mp_t action = NULL;
RTE_LOG(DEBUG, EAL, "msg: %s\n", msg->name);
if (m->type == MP_REP) {
pthread_mutex_lock(&sync_requests.lock);
sync_req = find_sync_request(s->sun_path, msg->name);
if (sync_req) {
memcpy(sync_req->reply, msg, sizeof(*msg));
sync_req->reply_received = 1;
pthread_cond_signal(&sync_req->cond);
} else
RTE_LOG(ERR, EAL, "Drop mp reply: %s\n", msg->name);
pthread_mutex_unlock(&sync_requests.lock);
return;
}
pthread_mutex_lock(&mp_mutex_action);
entry = find_action_entry_by_name(msg->name);
if (entry != NULL)
@ -206,18 +269,19 @@ process_msg(struct rte_mp_msg *msg)
if (!action)
RTE_LOG(ERR, EAL, "Cannot find action: %s\n", msg->name);
else if (action(msg) < 0)
else if (action(msg, s->sun_path) < 0)
RTE_LOG(ERR, EAL, "Fail to handle message: %s\n", msg->name);
}
static void *
mp_handle(void *arg __rte_unused)
{
struct rte_mp_msg msg;
struct mp_msg_internal msg;
struct sockaddr_un sa;
while (1) {
if (read_msg(&msg) == 0)
process_msg(&msg);
if (read_msg(&msg, &sa) == 0)
process_msg(&msg, &sa);
}
return NULL;
@ -336,16 +400,20 @@ rte_mp_channel_init(void)
*
*/
static int
send_msg(const char *dst_path, struct rte_mp_msg *msg)
send_msg(const char *dst_path, struct rte_mp_msg *msg, int type)
{
int snd;
struct iovec iov;
struct msghdr msgh;
struct cmsghdr *cmsg;
struct sockaddr_un dst;
struct mp_msg_internal m;
int fd_size = msg->num_fds * sizeof(int);
char control[CMSG_SPACE(fd_size)];
m.type = type;
memcpy(&m.msg, msg, sizeof(*msg));
memset(&dst, 0, sizeof(dst));
dst.sun_family = AF_UNIX;
snprintf(dst.sun_path, sizeof(dst.sun_path), "%s", dst_path);
@ -353,8 +421,8 @@ send_msg(const char *dst_path, struct rte_mp_msg *msg)
memset(&msgh, 0, sizeof(msgh));
memset(control, 0, sizeof(control));
iov.iov_base = msg;
iov.iov_len = sizeof(*msg) - sizeof(msg->fds);
iov.iov_base = &m;
iov.iov_len = sizeof(m) - sizeof(msg->fds);
msgh.msg_name = &dst;
msgh.msg_namelen = sizeof(dst);
@ -396,14 +464,17 @@ send_msg(const char *dst_path, struct rte_mp_msg *msg)
}
static int
mp_send(struct rte_mp_msg *msg)
mp_send(struct rte_mp_msg *msg, const char *peer, int type)
{
int ret = 0;
DIR *mp_dir;
struct dirent *ent;
if (rte_eal_process_type() == RTE_PROC_SECONDARY) {
if (send_msg(eal_mp_socket_path(), msg) < 0)
if (!peer && (rte_eal_process_type() == RTE_PROC_SECONDARY))
peer = eal_mp_socket_path();
if (peer) {
if (send_msg(peer, msg, type) < 0)
return -1;
else
return 0;
@ -421,11 +492,11 @@ mp_send(struct rte_mp_msg *msg)
if (fnmatch(mp_filter, ent->d_name, 0) != 0)
continue;
if (send_msg(ent->d_name, msg) < 0)
if (send_msg(ent->d_name, msg, type) < 0)
ret = -1;
}
closedir(mp_dir);
closedir(mp_dir);
return ret;
}
@ -464,5 +535,150 @@ rte_mp_sendmsg(struct rte_mp_msg *msg)
return -1;
RTE_LOG(DEBUG, EAL, "sendmsg: %s\n", msg->name);
return mp_send(msg);
return mp_send(msg, NULL, MP_MSG);
}
static int
mp_request_one(const char *dst, struct rte_mp_msg *req,
struct rte_mp_reply *reply, const struct timespec *ts)
{
int ret;
struct timeval now;
struct rte_mp_msg msg, *tmp;
struct sync_request sync_req, *exist;
sync_req.reply_received = 0;
strcpy(sync_req.dst, dst);
sync_req.request = req;
sync_req.reply = &msg;
pthread_cond_init(&sync_req.cond, NULL);
pthread_mutex_lock(&sync_requests.lock);
exist = find_sync_request(dst, req->name);
if (!exist)
TAILQ_INSERT_TAIL(&sync_requests.requests, &sync_req, next);
pthread_mutex_unlock(&sync_requests.lock);
if (exist) {
RTE_LOG(ERR, EAL, "A pending request %s:%s\n", dst, req->name);
rte_errno = -EEXIST;
return -1;
}
ret = send_msg(dst, req, MP_REQ);
if (ret < 0) {
RTE_LOG(ERR, EAL, "Fail to send request %s:%s\n",
dst, req->name);
return -1;
} else if (ret == 0)
return 0;
reply->nb_sent++;
pthread_mutex_lock(&sync_requests.lock);
do {
pthread_cond_timedwait(&sync_req.cond, &sync_requests.lock, ts);
/* Check spurious wakeups */
if (sync_req.reply_received == 1)
break;
/* Check if time is out */
if (gettimeofday(&now, NULL) < 0)
break;
if (now.tv_sec < ts->tv_sec)
break;
else if (now.tv_sec == ts->tv_sec &&
now.tv_usec * 1000 < ts->tv_nsec)
break;
} while (1);
/* We got the lock now */
TAILQ_REMOVE(&sync_requests.requests, &sync_req, next);
pthread_mutex_unlock(&sync_requests.lock);
if (sync_req.reply_received == 0) {
RTE_LOG(ERR, EAL, "Fail to recv reply for request %s:%s\n",
dst, req->name);
rte_errno = -ETIMEDOUT;
return -1;
}
tmp = realloc(reply->msgs, sizeof(msg) * (reply->nb_received + 1));
if (!tmp) {
RTE_LOG(ERR, EAL, "Fail to alloc reply for request %s:%s\n",
dst, req->name);
rte_errno = -ENOMEM;
return -1;
}
memcpy(&tmp[reply->nb_received], &msg, sizeof(msg));
reply->msgs = tmp;
reply->nb_received++;
return 0;
}
int __rte_experimental
rte_mp_request(struct rte_mp_msg *req, struct rte_mp_reply *reply,
const struct timespec *ts)
{
int ret = 0;
DIR *mp_dir;
struct dirent *ent;
struct timeval now;
struct timespec end;
RTE_LOG(DEBUG, EAL, "request: %s\n", req->name);
if (check_input(req) == false)
return -1;
if (gettimeofday(&now, NULL) < 0) {
RTE_LOG(ERR, EAL, "Faile to get current time\n");
rte_errno = errno;
return -1;
}
end.tv_nsec = (now.tv_usec * 1000 + ts->tv_nsec) % 1000000000;
end.tv_sec = now.tv_sec + ts->tv_sec +
(now.tv_usec * 1000 + ts->tv_nsec) / 1000000000;
reply->nb_sent = 0;
reply->nb_received = 0;
reply->msgs = NULL;
/* for secondary process, send request to the primary process only */
if (rte_eal_process_type() == RTE_PROC_SECONDARY)
return mp_request_one(eal_mp_socket_path(), req, reply, &end);
/* for primary process, broadcast request, and collect reply 1 by 1 */
mp_dir = opendir(mp_dir_path);
if (!mp_dir) {
RTE_LOG(ERR, EAL, "Unable to open directory %s\n", mp_dir_path);
rte_errno = errno;
return -1;
}
while ((ent = readdir(mp_dir))) {
if (fnmatch(mp_filter, ent->d_name, 0) != 0)
continue;
if (mp_request_one(ent->d_name, req, reply, &end))
ret = -1;
}
closedir(mp_dir);
return ret;
}
int __rte_experimental
rte_mp_reply(struct rte_mp_msg *msg, const char *peer)
{
RTE_LOG(DEBUG, EAL, "reply: %s\n", msg->name);
if (check_input(msg) == false)
return -1;
if (peer == NULL) {
RTE_LOG(ERR, EAL, "peer is not specified\n");
rte_errno = -EINVAL;
return -1;
}
return mp_send(msg, peer, MP_REP);
}

60
lib/librte_eal/common/include/rte_eal.h
View File

@ -13,6 +13,7 @@
#include <stdint.h>
#include <sched.h>
#include <time.h>
#include <rte_config.h>
#include <rte_compat.h>
@ -214,13 +215,19 @@ struct rte_mp_msg {
int fds[RTE_MP_MAX_FD_NUM];
};
struct rte_mp_reply {
int nb_sent;
int nb_received;
struct rte_mp_msg *msgs; /* caller to free */
};
/**
* Action function typedef used by other components.
*
* As we create socket channel for primary/secondary communication, use
* this function typedef to register action for coming messages.
*/
typedef int (*rte_mp_t)(const struct rte_mp_msg *msg);
typedef int (*rte_mp_t)(const struct rte_mp_msg *msg, const void *peer);
/**
* @warning
@ -281,6 +288,57 @@ rte_mp_action_unregister(const char *name);
int __rte_experimental
rte_mp_sendmsg(struct rte_mp_msg *msg);
/**
* @warning
* @b EXPERIMENTAL: this API may change without prior notice
*
* Send a request to the peer process and expect a reply.
*
* This function sends a request message to the peer process, and will
* block until receiving reply message from the peer process.
*
* @note The caller is responsible to free reply->replies.
*
* @param req
* The req argument contains the customized request message.
*
* @param reply
* The reply argument will be for storing all the replied messages;
* the caller is responsible for free reply->replies.
*
* @param ts
* The ts argument specifies how long we can wait for the peer(s) to reply.
*
* @return
* - On success, return 0.
* - On failure, return -1, and the reason will be stored in rte_errno.
*/
int __rte_experimental
rte_mp_request(struct rte_mp_msg *req, struct rte_mp_reply *reply,
const struct timespec *ts);
/**
* @warning
* @b EXPERIMENTAL: this API may change without prior notice
*
* Send a reply to the peer process.
*
* This function will send a reply message in response to a request message
* received previously.
*
* @param msg
* The msg argument contains the customized message.
*
* @param peer
* The peer argument is the pointer to the peer socket path.
*
* @return
* - On success, return 0.
* - On failure, return -1, and the reason will be stored in rte_errno.
*/
int __rte_experimental
rte_mp_reply(struct rte_mp_msg *msg, const char *peer);
/**
* Usage function typedef used by the application usage function.
*

2
lib/librte_eal/rte_eal_version.map
View File

@ -223,6 +223,8 @@ EXPERIMENTAL {
rte_mp_action_register;
rte_mp_action_unregister;
rte_mp_sendmsg;
rte_mp_request;
rte_mp_reply;
rte_service_attr_get;
rte_service_attr_reset_all;
rte_service_component_register;