vcl: unset fifo events only in read/write

Avoids accumulation of io event messages when the receiver is slow to
read.

Change-Id: I3a713d339a6ac0781c010be1fbad5a7963ab02c6
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 21 insertions, 57 deletions

diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 8572b69aa13..29936aa5207 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -1339,12 +1339,11 @@ vppcom_session_read_internal (uint32_t session_index, void *buf, int n,
 	      continue;
 	    }
 	  svm_fifo_unset_event (rx_fifo);
-	  if (svm_fifo_is_empty (rx_fifo))
-	    {
-	      svm_msg_q_free_msg (mq, &msg);
-	      continue;
-	    }
 	  svm_msg_q_free_msg (mq, &msg);
+	  if (PREDICT_FALSE (s->session_state == STATE_CLOSE_ON_EMPTY))
+	    return 0;
+	  if (svm_fifo_is_empty (rx_fifo))
+	    continue;
 	  break;
 	}
     }
@@ -1483,14 +1482,9 @@ vppcom_session_write (uint32_t session_index, void *buf, size_t n)
 	  rv = VPPCOM_EWOULDBLOCK;
 	  goto done;
 	}
-      while (1)
+      while (svm_fifo_is_full (tx_fifo))
 	{
 	  svm_msg_q_lock (mq);
-	  if (!svm_fifo_is_full (tx_fifo))
-	    {
-	      svm_msg_q_unlock (mq);
-	      break;
-	    }
 	  while (svm_msg_q_is_empty (mq) && svm_msg_q_timedwait (mq, 10e-6))
 	    ;
 	  svm_msg_q_sub_w_lock (mq, &msg);
@@ -1499,18 +1493,8 @@ vppcom_session_write (uint32_t session_index, void *buf, size_t n)
 
 	  if (!vcl_is_tx_evt_for_session (e, session_index,
 					  s->our_evt_q != 0))
-	    {
-	      vcl_handle_mq_ctrl_event (e);
-	      svm_msg_q_free_msg (mq, &msg);
-	      continue;
-	    }
-	  if (svm_fifo_is_full (tx_fifo))
-	    {
-	      svm_msg_q_free_msg (mq, &msg);
-	      continue;
-	    }
+	    vcl_handle_mq_ctrl_event (e);
 	  svm_msg_q_free_msg (mq, &msg);
-	  break;
 	}
     }
 
@@ -1680,9 +1664,6 @@ vcl_select_handle_mq (svm_msg_q_t * mq, unsigned long n_bits,
 	case FIFO_EVENT_APP_RX:
 	  sid = e->fifo->client_session_index;
 	  session = vcl_session_get (sid);
-	  svm_fifo_unset_event (session->rx_fifo);
-	  if (svm_fifo_is_empty (session->rx_fifo))
-	    break;
 	  if (sid < n_bits && read_map)
 	    {
 	      clib_bitmap_set_no_check (read_map, sid, 1);
@@ -1692,7 +1673,7 @@ vcl_select_handle_mq (svm_msg_q_t * mq, unsigned long n_bits,
 	case FIFO_EVENT_APP_TX:
 	  sid = e->fifo->client_session_index;
 	  session = vcl_session_get (sid);
-	  if (!session || svm_fifo_is_full (session->tx_fifo))
+	  if (!session)
 	    break;
 	  if (sid < n_bits && write_map)
 	    {
@@ -1703,9 +1684,6 @@ vcl_select_handle_mq (svm_msg_q_t * mq, unsigned long n_bits,
 	case SESSION_IO_EVT_CT_TX:
 	  session = vcl_ct_session_get_from_fifo (e->fifo, 0);
 	  sid = vcl_session_index (session);
-	  svm_fifo_unset_event (session->rx_fifo);
-	  if (svm_fifo_is_empty (session->rx_fifo))
-	    break;
 	  if (sid < n_bits && read_map)
 	    {
 	      clib_bitmap_set_no_check (read_map, sid, 1);
@@ -1716,7 +1694,7 @@ vcl_select_handle_mq (svm_msg_q_t * mq, unsigned long n_bits,
 	case SESSION_IO_EVT_CT_RX:
 	  session = vcl_ct_session_get_from_fifo (e->fifo, 1);
 	  sid = vcl_session_index (session);
-	  if (!session || svm_fifo_is_full (session->tx_fifo))
+	  if (!session)
 	    break;
 	  if (sid < n_bits && write_map)
 	    {
@@ -2267,7 +2245,7 @@ vcl_epoll_wait_handle_mq (svm_msg_q_t * mq, struct epoll_event *events,
 	}
       else
 	{
-	  if (svm_msg_q_timedwait (mq, wait_for_time / 1e3) < 0)
+	  if (svm_msg_q_timedwait (mq, wait_for_time / 1e3))
 	    {
 	      svm_msg_q_unlock (mq);
 	      return 0;
@@ -2290,13 +2268,9 @@ vcl_epoll_wait_handle_mq (svm_msg_q_t * mq, struct epoll_event *events,
 	  session_events = session->vep.ev.events;
 	  if (!(EPOLLIN & session->vep.ev.events))
 	    break;
-	  svm_fifo_unset_event (session->rx_fifo);
-	  if (!svm_fifo_is_empty (session->rx_fifo))
-	    {
-	      add_event = 1;
-	      events[*num_ev].events |= EPOLLIN;
-	      session_evt_data = session->vep.ev.data.u64;
-	    }
+	  add_event = 1;
+	  events[*num_ev].events |= EPOLLIN;
+	  session_evt_data = session->vep.ev.data.u64;
 	  break;
 	case FIFO_EVENT_APP_TX:
 	  sid = e->fifo->client_session_index;
@@ -2304,12 +2278,9 @@ vcl_epoll_wait_handle_mq (svm_msg_q_t * mq, struct epoll_event *events,
 	  session_events = session->vep.ev.events;
 	  if (!(EPOLLOUT & session_events))
 	    break;
-	  if (!svm_fifo_is_full (session->tx_fifo))
-	    {
-	      add_event = 1;
-	      events[*num_ev].events |= EPOLLOUT;
-	      session_evt_data = session->vep.ev.data.u64;
-	    }
+	  add_event = 1;
+	  events[*num_ev].events |= EPOLLOUT;
+	  session_evt_data = session->vep.ev.data.u64;
 	  break;
 	case SESSION_IO_EVT_CT_TX:
 	  session = vcl_ct_session_get_from_fifo (e->fifo, 0);
@@ -2317,13 +2288,9 @@ vcl_epoll_wait_handle_mq (svm_msg_q_t * mq, struct epoll_event *events,
 	  session_events = session->vep.ev.events;
 	  if (!(EPOLLIN & session->vep.ev.events))
 	    break;
-	  svm_fifo_unset_event (session->rx_fifo);
-	  if (!svm_fifo_is_empty (session->rx_fifo))
-	    {
-	      add_event = 1;
-	      events[*num_ev].events |= EPOLLIN;
-	      session_evt_data = session->vep.ev.data.u64;
-	    }
+	  add_event = 1;
+	  events[*num_ev].events |= EPOLLIN;
+	  session_evt_data = session->vep.ev.data.u64;
 	  break;
 	case SESSION_IO_EVT_CT_RX:
 	  session = vcl_ct_session_get_from_fifo (e->fifo, 1);
@@ -2331,12 +2298,9 @@ vcl_epoll_wait_handle_mq (svm_msg_q_t * mq, struct epoll_event *events,
 	  session_events = session->vep.ev.events;
 	  if (!(EPOLLOUT & session_events))
 	    break;
-	  if (!svm_fifo_is_full (session->tx_fifo))
-	    {
-	      add_event = 1;
-	      events[*num_ev].events |= EPOLLOUT;
-	      session_evt_data = session->vep.ev.data.u64;
-	    }
+	  add_event = 1;
+	  events[*num_ev].events |= EPOLLOUT;
+	  session_evt_data = session->vep.ev.data.u64;
 	  break;
 	case SESSION_CTRL_EVT_ACCEPTED:
 	  accepted_msg = (session_accepted_msg_t *) e->data;