vcl: fix epoll ctl frequent deq ntf requests

[vpp.git] / src / vcl / vppcom.c

diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 474670e..f2166f8 100644 (file)
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -2868,15 +2868,22 @@ vppcom_epoll_ctl (uint32_t vep_handle, int op, uint32_t session_handle,
       s->flags |= VCL_SESSION_F_IS_VEP_SESSION;
       vep_session->vep.next_sh = session_handle;
 
-      if (event->events & EPOLLOUT)
-       vcl_session_add_want_deq_ntf (s, SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL);
-
-      /* Generate EPOLLOUT if tx fifo not full */
-      if ((event->events & EPOLLOUT) && (vcl_session_write_ready (s) > 0))
+      if ((event->events & EPOLLOUT))
        {
-         vcl_epoll_ctl_add_unhandled_event (wrk, s, event->events & EPOLLET,
-                                            SESSION_IO_EVT_TX);
-         add_evt = 1;
+         int write_ready = vcl_session_write_ready (s);
+
+         vcl_session_add_want_deq_ntf (s, SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL);
+         if (write_ready > 0)
+           {
+             /* Generate EPOLLOUT if tx fifo not full */
+             vcl_epoll_ctl_add_unhandled_event (
+               wrk, s, event->events & EPOLLET, SESSION_IO_EVT_TX);
+             add_evt = 1;
+           }
+         else
+           {
+             vcl_session_add_want_deq_ntf (s, SVM_FIFO_WANT_DEQ_NOTIF);
+           }
        }
       /* Generate EPOLLIN if rx fifo has data */
       if ((event->events & EPOLLIN) && (vcl_session_read_ready (s) > 0))
@@ -2922,18 +2929,23 @@ vppcom_epoll_ctl (uint32_t vep_handle, int op, uint32_t session_handle,
          goto done;
        }
 
-      if (event->events & EPOLLOUT)
-       vcl_session_add_want_deq_ntf (s, SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL);
-      else
-       vcl_session_del_want_deq_ntf (s, SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL);
-
-      /* Generate EPOLLOUT if session write ready nd event was not on */
-      if ((event->events & EPOLLOUT) && !(s->vep.ev.events & EPOLLOUT) &&
-         (vcl_session_write_ready (s) > 0))
+      /* Generate EPOLLOUT if session write ready and event was not on */
+      if ((event->events & EPOLLOUT) && !(s->vep.ev.events & EPOLLOUT))
        {
-         vcl_epoll_ctl_add_unhandled_event (wrk, s, event->events & EPOLLET,
-                                            SESSION_IO_EVT_TX);
+         /* Fifo size load acq synchronized with update store rel */
+         int write_ready = vcl_session_write_ready (s);
+
+         vcl_session_add_want_deq_ntf (s, SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL);
+         if (write_ready > 0)
+           vcl_epoll_ctl_add_unhandled_event (wrk, s, event->events & EPOLLET,
+                                              SESSION_IO_EVT_TX);
+         else
+           /* Request deq ntf in case dequeue happened while updating flag */
+           vcl_session_add_want_deq_ntf (s, SVM_FIFO_WANT_DEQ_NOTIF);
        }
+      else if (!(event->events & EPOLLOUT))
+       vcl_session_del_want_deq_ntf (s, SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL);
+
       /* Generate EPOLLIN if session read ready and event was not on */
       if ((event->events & EPOLLIN) && !(s->vep.ev.events & EPOLLIN) &&
          (vcl_session_read_ready (s) > 0))