3 files changed, 60 insertions, 0 deletions

diff --git a/src/vcl/vcl_private.c b/src/vcl/vcl_private.c
index 6892688da5a..7a9b60a1959 100644
--- a/src/vcl/vcl_private.c
+++ b/src/vcl/vcl_private.c
@@ -189,6 +189,55 @@ vcl_worker_cleanup_cb (void *arg)
 }
 
 void
+vcl_worker_detached_start_signal_mq (vcl_worker_t *wrk)
+{
+  /* Generate mq epfd events using pipes to hopefully force
+   * calls into epoll_wait which retries attaching to vpp */
+  if (!wrk->detached_pipefds[0])
+    {
+      if (pipe (wrk->detached_pipefds))
+	{
+	  VDBG (0, "failed to add mq eventfd to mq epoll fd");
+	  exit (1);
+	}
+    }
+
+  struct epoll_event evt = {};
+  evt.events = EPOLLIN;
+  evt.data.u32 = wrk->detached_pipefds[0];
+  if (epoll_ctl (wrk->mqs_epfd, EPOLL_CTL_ADD, wrk->detached_pipefds[0],
+		 &evt) < 0)
+    {
+      VDBG (0, "failed to add mq eventfd to mq epoll fd");
+      exit (1);
+    }
+
+  int __clib_unused rv;
+  u8 sig = 1;
+  rv = write (wrk->detached_pipefds[1], &sig, 1);
+}
+
+void
+vcl_worker_detached_signal_mq (vcl_worker_t *wrk)
+{
+  int __clib_unused rv;
+  u8 buf;
+  rv = read (wrk->detached_pipefds[0], &buf, 1);
+  rv = write (wrk->detached_pipefds[1], &buf, 1);
+}
+
+void
+vcl_worker_detached_stop_signal_mq (vcl_worker_t *wrk)
+{
+  if (epoll_ctl (wrk->mqs_epfd, EPOLL_CTL_DEL, wrk->detached_pipefds[0], 0) <
+      0)
+    {
+      VDBG (0, "failed to del mq eventfd to mq epoll fd");
+      exit (1);
+    }
+}
+
+void
 vcl_worker_detach_sessions (vcl_worker_t *wrk)
 {
   session_event_t *e;
@@ -239,6 +288,8 @@ vcl_worker_detach_sessions (vcl_worker_t *wrk)
 
   vec_free (seg_indices);
   hash_free (seg_indices_map);
+
+  vcl_worker_detached_start_signal_mq (wrk);
 }
 
 void
diff --git a/src/vcl/vcl_private.h b/src/vcl/vcl_private.h
index c92bb58169d..72f0a8327f0 100644
--- a/src/vcl/vcl_private.h
+++ b/src/vcl/vcl_private.h
@@ -325,6 +325,9 @@ typedef struct vcl_worker_
   /* functions to be called pre/post wait if vcl managed by vls */
   vcl_worker_wait_mq_fn pre_wait_fn;
   vcl_worker_wait_mq_fn post_wait_fn;
+
+  /* mq_epfd signal pipes when wrk detached from vpp */
+  int detached_pipefds[2];
 } vcl_worker_t;
 
 STATIC_ASSERT (sizeof (session_disconnected_msg_t) <= 16,
@@ -799,6 +802,9 @@ void vcl_worker_detach_sessions (vcl_worker_t *wrk);
 void vcl_worker_set_wait_mq_fns (vcl_worker_wait_mq_fn pre_wait,
 				 vcl_worker_wait_mq_fn post_wait);
 
+void vcl_worker_detached_start_signal_mq (vcl_worker_t *wrk);
+void vcl_worker_detached_signal_mq (vcl_worker_t *wrk);
+void vcl_worker_detached_stop_signal_mq (vcl_worker_t *wrk);
 /*
  * VCL Binary API
  */
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 1e9c915ce39..8bc5f42d4a6 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -1404,6 +1404,8 @@ vcl_api_retry_attach (vcl_worker_t *wrk)
 {
   vcl_session_t *s;
 
+  vcl_worker_detached_signal_mq (wrk);
+
   clib_spinlock_lock (&vcm->workers_lock);
   if (vcl_is_first_reattach_to_execute ())
     {
@@ -1412,6 +1414,7 @@ vcl_api_retry_attach (vcl_worker_t *wrk)
 	  clib_spinlock_unlock (&vcm->workers_lock);
 	  return;
 	}
+      vcl_worker_detached_stop_signal_mq (wrk);
       vcl_set_reattach_counter ();
       clib_spinlock_unlock (&vcm->workers_lock);
     }