session: app mq congestion detection

Detect mq congestion and handle it by queueing messages in a fifo and
postponing handling via rpcs. App workers with congested mqs cannot
accept nor connect additional sessions.

Type: feature

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I401d971a1a53896758b88fc60f158cbc31e0c7cb

1 files changed, 43 insertions, 224 deletions

diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index 767a24aa170..f6170debba7 100644
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -82,40 +82,12 @@ session_send_fds (vl_api_registration_t * reg, int fds[], int n_fds)
 }
 
 static int
-mq_try_lock_and_alloc_msg (svm_msg_q_t * app_mq, svm_msg_q_msg_t * msg)
-{
-  int rv;
-  u8 try = 0;
-  while (try < 100)
-    {
-      rv = svm_msg_q_lock_and_alloc_msg_w_ring (app_mq,
-						SESSION_MQ_CTRL_EVT_RING,
-						SVM_Q_NOWAIT, msg);
-      if (!rv)
-	return 0;
-      /*
-       * Break the loop if mq is full, usually this is because the
-       * app has crashed or is hanging on somewhere.
-       */
-      if (rv != -1)
-	break;
-      try++;
-      usleep (1);
-    }
-  clib_warning ("failed to alloc msg");
-  return -1;
-}
-
-static int
 mq_send_session_accepted_cb (session_t * s)
 {
   app_worker_t *app_wrk = app_worker_get (s->app_wrk_index);
-  svm_msg_q_msg_t _msg, *msg = &_msg;
   session_accepted_msg_t m = { 0 };
-  svm_msg_q_t *app_mq;
   fifo_segment_t *eq_seg;
   session_t *listener;
-  session_event_t *evt;
   application_t *app;
 
   app = application_get (app_wrk->app_index);
@@ -164,15 +136,7 @@ mq_send_session_accepted_cb (session_t * s)
       m.mq_index = s->thread_index;
     }
 
-  app_mq = app_wrk->event_queue;
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return SESSION_E_MQ_MSG_ALLOC;
-
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_ACCEPTED;
-  clib_memcpy_fast (evt->data, &m, sizeof (m));
-  svm_msg_q_add_and_unlock (app_mq, msg);
+  app_wrk_send_ctrl_evt (app_wrk, SESSION_CTRL_EVT_ACCEPTED, &m, sizeof (m));
 
   return 0;
 }
@@ -181,21 +145,12 @@ static inline void
 mq_send_session_close_evt (app_worker_t * app_wrk, session_handle_t sh,
 			   session_evt_type_t evt_type)
 {
-  svm_msg_q_msg_t _msg, *msg = &_msg;
-  session_disconnected_msg_t *mp;
-  svm_msg_q_t *app_mq;
-  session_event_t *evt;
+  session_disconnected_msg_t m = { 0 };
 
-  app_mq = app_wrk->event_queue;
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return;
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = evt_type;
-  mp = (session_disconnected_msg_t *) evt->data;
-  mp->handle = sh;
-  mp->context = app_wrk->api_client_index;
-  svm_msg_q_add_and_unlock (app_mq, msg);
+  m.handle = sh;
+  m.context = app_wrk->api_client_index;
+
+  app_wrk_send_ctrl_evt (app_wrk, evt_type, &m, sizeof (m));
 }
 
 static inline void
@@ -249,13 +204,10 @@ int
 mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
 			      session_t * s, session_error_t err)
 {
-  svm_msg_q_msg_t _msg, *msg = &_msg;
   session_connected_msg_t m = { 0 };
-  svm_msg_q_t *app_mq;
   transport_connection_t *tc;
   fifo_segment_t *eq_seg;
   app_worker_t *app_wrk;
-  session_event_t *evt;
   application_t *app;
 
   app_wrk = app_worker_get (app_wrk_index);
@@ -318,17 +270,8 @@ mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
 
 snd_msg:
 
-  app_mq = app_wrk->event_queue;
-
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return SESSION_E_MQ_MSG_ALLOC;
-
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_CONNECTED;
-  clib_memcpy_fast (evt->data, &m, sizeof (m));
+  app_wrk_send_ctrl_evt (app_wrk, SESSION_CTRL_EVT_CONNECTED, &m, sizeof (m));
 
-  svm_msg_q_add_and_unlock (app_mq, msg);
   return 0;
 }
 
@@ -336,13 +279,10 @@ int
 mq_send_session_bound_cb (u32 app_wrk_index, u32 api_context,
 			  session_handle_t handle, int rv)
 {
-  svm_msg_q_msg_t _msg, *msg = &_msg;
   session_bound_msg_t m = { 0 };
-  svm_msg_q_t *app_mq;
   transport_endpoint_t tep;
   fifo_segment_t *eq_seg;
   app_worker_t *app_wrk;
-  session_event_t *evt;
   application_t *app;
   app_listener_t *al;
   session_t *ls = 0;
@@ -381,17 +321,8 @@ mq_send_session_bound_cb (u32 app_wrk_index, u32 api_context,
 
 snd_msg:
 
-  app_mq = app_wrk->event_queue;
+  app_wrk_send_ctrl_evt (app_wrk, SESSION_CTRL_EVT_BOUND, &m, sizeof (m));
 
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return SESSION_E_MQ_MSG_ALLOC;
-
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_BOUND;
-  clib_memcpy_fast (evt->data, &m, sizeof (m));
-
-  svm_msg_q_add_and_unlock (app_mq, msg);
   return 0;
 }
 
@@ -399,40 +330,26 @@ void
 mq_send_unlisten_reply (app_worker_t * app_wrk, session_handle_t sh,
 			u32 context, int rv)
 {
-  svm_msg_q_msg_t _msg, *msg = &_msg;
-  session_unlisten_reply_msg_t *ump;
-  svm_msg_q_t *app_mq;
-  session_event_t *evt;
-
-  app_mq = app_wrk->event_queue;
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return;
+  session_unlisten_reply_msg_t m = { 0 };
 
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_UNLISTEN_REPLY;
-  ump = (session_unlisten_reply_msg_t *) evt->data;
-  ump->context = context;
-  ump->handle = sh;
-  ump->retval = rv;
-  svm_msg_q_add_and_unlock (app_mq, msg);
+  m.context = context;
+  m.handle = sh;
+  m.retval = rv;
+  app_wrk_send_ctrl_evt (app_wrk, SESSION_CTRL_EVT_UNLISTEN_REPLY, &m,
+			 sizeof (m));
 }
 
 static void
 mq_send_session_migrate_cb (session_t * s, session_handle_t new_sh)
 {
-  svm_msg_q_msg_t _msg, *msg = &_msg;
   session_migrated_msg_t m = { 0 };
   fifo_segment_t *eq_seg;
   app_worker_t *app_wrk;
-  session_event_t *evt;
-  svm_msg_q_t *app_mq;
   application_t *app;
   u32 thread_index;
 
   thread_index = session_thread_from_handle (new_sh);
   app_wrk = app_worker_get (s->app_wrk_index);
-  app_mq = app_wrk->event_queue;
   app = application_get (app_wrk->app_index);
   eq_seg = application_get_rx_mqs_segment (app);
 
@@ -442,27 +359,15 @@ mq_send_session_migrate_cb (session_t * s, session_handle_t new_sh)
   m.vpp_evt_q = fifo_segment_msg_q_offset (eq_seg, thread_index);
   m.segment_handle = SESSION_INVALID_HANDLE;
 
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return;
-
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_MIGRATED;
-  clib_memcpy_fast (evt->data, &m, sizeof (m));
-
-  svm_msg_q_add_and_unlock (app_mq, msg);
+  app_wrk_send_ctrl_evt (app_wrk, SESSION_CTRL_EVT_MIGRATED, &m, sizeof (m));
 }
 
 static int
 mq_send_add_segment_cb (u32 app_wrk_index, u64 segment_handle)
 {
-  int fds[SESSION_N_FD_TYPE], n_fds = 0;
-  svm_msg_q_msg_t _msg, *msg = &_msg;
-  session_app_add_segment_msg_t *mp;
+  session_app_add_segment_msg_t m = { 0 };
   vl_api_registration_t *reg;
   app_worker_t *app_wrk;
-  session_event_t *evt;
-  svm_msg_q_t *app_mq;
   fifo_segment_t *fs;
   ssvm_private_t *sp;
   u8 fd_flags = 0;
@@ -488,29 +393,16 @@ mq_send_add_segment_cb (u32 app_wrk_index, u64 segment_handle)
 	}
 
       fd_flags |= SESSION_FD_F_MEMFD_SEGMENT;
-      fds[n_fds] = sp->fd;
-      n_fds += 1;
     }
 
-  app_mq = app_wrk->event_queue;
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return -1;
-
-  if (n_fds)
-    session_send_fds (reg, fds, n_fds);
-
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_APP_ADD_SEGMENT;
-  mp = (session_app_add_segment_msg_t *) evt->data;
-  clib_memset (mp, 0, sizeof (*mp));
-  mp->segment_size = sp->ssvm_size;
-  mp->fd_flags = fd_flags;
-  mp->segment_handle = segment_handle;
-  strncpy ((char *) mp->segment_name, (char *) sp->name,
-	   sizeof (mp->segment_name) - 1);
+  m.segment_size = sp->ssvm_size;
+  m.fd_flags = fd_flags;
+  m.segment_handle = segment_handle;
+  strncpy ((char *) m.segment_name, (char *) sp->name,
+	   sizeof (m.segment_name) - 1);
 
-  svm_msg_q_add_and_unlock (app_mq, msg);
+  app_wrk_send_ctrl_evt_fd (app_wrk, SESSION_CTRL_EVT_APP_ADD_SEGMENT, &m,
+			    sizeof (m), sp->fd);
 
   return 0;
 }
@@ -518,12 +410,9 @@ mq_send_add_segment_cb (u32 app_wrk_index, u64 segment_handle)
 static int
 mq_send_del_segment_cb (u32 app_wrk_index, u64 segment_handle)
 {
-  svm_msg_q_msg_t _msg, *msg = &_msg;
-  session_app_del_segment_msg_t *mp;
+  session_app_del_segment_msg_t m = { 0 };
   vl_api_registration_t *reg;
   app_worker_t *app_wrk;
-  session_event_t *evt;
-  svm_msg_q_t *app_mq;
 
   app_wrk = app_worker_get (app_wrk_index);
   reg = vl_mem_api_client_index_to_registration (app_wrk->api_client_index);
@@ -533,17 +422,10 @@ mq_send_del_segment_cb (u32 app_wrk_index, u64 segment_handle)
       return -1;
     }
 
-  app_mq = app_wrk->event_queue;
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return -1;
+  m.segment_handle = segment_handle;
 
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_APP_DEL_SEGMENT;
-  mp = (session_app_del_segment_msg_t *) evt->data;
-  clib_memset (mp, 0, sizeof (*mp));
-  mp->segment_handle = segment_handle;
-  svm_msg_q_add_and_unlock (app_mq, msg);
+  app_wrk_send_ctrl_evt (app_wrk, SESSION_CTRL_EVT_APP_DEL_SEGMENT, &m,
+			 sizeof (m));
 
   return 0;
 }
@@ -551,10 +433,7 @@ mq_send_del_segment_cb (u32 app_wrk_index, u64 segment_handle)
 static void
 mq_send_session_cleanup_cb (session_t * s, session_cleanup_ntf_t ntf)
 {
-  svm_msg_q_msg_t _msg, *msg = &_msg;
-  session_cleanup_msg_t *mp;
-  svm_msg_q_t *app_mq;
-  session_event_t *evt;
+  session_cleanup_msg_t m = { 0 };
   app_worker_t *app_wrk;
 
   /* Propagate transport cleanup notifications only if app didn't close */
@@ -566,17 +445,10 @@ mq_send_session_cleanup_cb (session_t * s, session_cleanup_ntf_t ntf)
   if (!app_wrk)
     return;
 
-  app_mq = app_wrk->event_queue;
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return;
+  m.handle = session_handle (s);
+  m.type = ntf;
 
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_CLEANUP;
-  mp = (session_cleanup_msg_t *) evt->data;
-  mp->handle = session_handle (s);
-  mp->type = ntf;
-  svm_msg_q_add_and_unlock (app_mq, msg);
+  app_wrk_send_ctrl_evt (app_wrk, SESSION_CTRL_EVT_CLEANUP, &m, sizeof (m));
 }
 
 static session_cb_vft_t session_mq_cb_vft = {
@@ -1245,36 +1117,11 @@ VL_MSG_API_REAPER_FUNCTION (application_reaper_cb);
  * Socket api functions
  */
 
-static void
-sapi_send_fds (app_worker_t * app_wrk, int *fds, int n_fds)
-{
-  app_sapi_msg_t smsg = { 0 };
-  app_namespace_t *app_ns;
-  application_t *app;
-  clib_socket_t *cs;
-  u32 cs_index;
-
-  app = application_get (app_wrk->app_index);
-  app_ns = app_namespace_get (app->ns_index);
-  cs_index = appns_sapi_handle_sock_index (app_wrk->api_client_index);
-  cs = appns_sapi_get_socket (app_ns, cs_index);
-  if (PREDICT_FALSE (!cs))
-    return;
-
-  /* There's no payload for the message only the type */
-  smsg.type = APP_SAPI_MSG_TYPE_SEND_FDS;
-  clib_socket_sendmsg (cs, &smsg, sizeof (smsg), fds, n_fds);
-}
-
 static int
 mq_send_add_segment_sapi_cb (u32 app_wrk_index, u64 segment_handle)
 {
-  int fds[SESSION_N_FD_TYPE], n_fds = 0;
-  svm_msg_q_msg_t _msg, *msg = &_msg;
-  session_app_add_segment_msg_t *mp;
+  session_app_add_segment_msg_t m = { 0 };
   app_worker_t *app_wrk;
-  session_event_t *evt;
-  svm_msg_q_t *app_mq;
   fifo_segment_t *fs;
   ssvm_private_t *sp;
   u8 fd_flags = 0;
@@ -1286,33 +1133,15 @@ mq_send_add_segment_sapi_cb (u32 app_wrk_index, u64 segment_handle)
   ASSERT (ssvm_type (sp) == SSVM_SEGMENT_MEMFD);
 
   fd_flags |= SESSION_FD_F_MEMFD_SEGMENT;
-  fds[n_fds] = sp->fd;
-  n_fds += 1;
-
-  app_mq = app_wrk->event_queue;
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return -1;
 
-  /*
-   * Send the fd over api socket
-   */
-  sapi_send_fds (app_wrk, fds, n_fds);
+  m.segment_size = sp->ssvm_size;
+  m.fd_flags = fd_flags;
+  m.segment_handle = segment_handle;
+  strncpy ((char *) m.segment_name, (char *) sp->name,
+	   sizeof (m.segment_name) - 1);
 
-  /*
-   * Send the actual message over mq
-   */
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_APP_ADD_SEGMENT;
-  mp = (session_app_add_segment_msg_t *) evt->data;
-  clib_memset (mp, 0, sizeof (*mp));
-  mp->segment_size = sp->ssvm_size;
-  mp->fd_flags = fd_flags;
-  mp->segment_handle = segment_handle;
-  strncpy ((char *) mp->segment_name, (char *) sp->name,
-	   sizeof (mp->segment_name) - 1);
-
-  svm_msg_q_add_and_unlock (app_mq, msg);
+  app_wrk_send_ctrl_evt_fd (app_wrk, SESSION_CTRL_EVT_APP_ADD_SEGMENT, &m,
+			    sizeof (m), sp->fd);
 
   return 0;
 }
@@ -1320,25 +1149,15 @@ mq_send_add_segment_sapi_cb (u32 app_wrk_index, u64 segment_handle)
 static int
 mq_send_del_segment_sapi_cb (u32 app_wrk_index, u64 segment_handle)
 {
-  svm_msg_q_msg_t _msg, *msg = &_msg;
-  session_app_del_segment_msg_t *mp;
+  session_app_del_segment_msg_t m = { 0 };
   app_worker_t *app_wrk;
-  session_event_t *evt;
-  svm_msg_q_t *app_mq;
 
   app_wrk = app_worker_get (app_wrk_index);
 
-  app_mq = app_wrk->event_queue;
-  if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return -1;
+  m.segment_handle = segment_handle;
 
-  evt = svm_msg_q_msg_data (app_mq, msg);
-  clib_memset (evt, 0, sizeof (*evt));
-  evt->event_type = SESSION_CTRL_EVT_APP_DEL_SEGMENT;
-  mp = (session_app_del_segment_msg_t *) evt->data;
-  clib_memset (mp, 0, sizeof (*mp));
-  mp->segment_handle = segment_handle;
-  svm_msg_q_add_and_unlock (app_mq, msg);
+  app_wrk_send_ctrl_evt (app_wrk, SESSION_CTRL_EVT_APP_DEL_SEGMENT, &m,
+			 sizeof (m));
 
   return 0;
 }