2 files changed, 418 insertions, 105 deletions

diff --git a/src/vcl/vcl_locked.c b/src/vcl/vcl_locked.c
index d69d391d626..fcbc0ea3a00 100644
--- a/src/vcl/vcl_locked.c
+++ b/src/vcl/vcl_locked.c
@@ -16,16 +16,30 @@
 #include <vcl/vcl_locked.h>
 #include <vcl/vcl_private.h>
 
+typedef struct vls_shared_data_
+{
+  clib_spinlock_t lock;
+  u32 owner_wrk_index;
+  u32 *workers_subscribed;
+  clib_bitmap_t *listeners;
+} vls_shared_data_t;
+
 typedef struct vcl_locked_session_
 {
   clib_spinlock_t lock;
   u32 session_index;
   u32 worker_index;
   u32 vls_index;
-  u32 *workers_subscribed;
-  clib_bitmap_t *listeners;
+  u32 shared_data_index;
 } vcl_locked_session_t;
 
+typedef struct vls_worker_
+{
+  vcl_locked_session_t *vls_pool;
+  uword *session_index_to_vlsh_table;
+  u32 wrk_index;
+} vls_worker_t;
+
 typedef struct vls_local_
 {
   int vls_wrk_index;
@@ -41,35 +55,102 @@ static vls_process_local_t *vlsl = &vls_local;
 
 typedef struct vls_main_
 {
-  vcl_locked_session_t *vls_pool;
+  vls_worker_t *workers;
   clib_rwlock_t vls_table_lock;
-  uword *session_index_to_vlsh_table;
+  /** Pool of data shared by sessions owned by different workers */
+  vls_shared_data_t *shared_data_pool;
+  clib_rwlock_t shared_data_lock;
 } vls_main_t;
 
 vls_main_t *vlsm;
 
+static inline u32
+vls_get_worker_index (void)
+{
+  return vcl_get_worker_index ();
+}
+
+static u32
+vls_shared_data_alloc (void)
+{
+  vls_shared_data_t *vls_shd;
+  u32 shd_index;
+
+  clib_rwlock_writer_lock (&vlsm->shared_data_lock);
+  pool_get_zero (vlsm->shared_data_pool, vls_shd);
+  clib_spinlock_init (&vls_shd->lock);
+  shd_index = vls_shd - vlsm->shared_data_pool;
+  clib_rwlock_writer_unlock (&vlsm->shared_data_lock);
+
+  return shd_index;
+}
+
+static u32
+vls_shared_data_index (vls_shared_data_t * vls_shd)
+{
+  return vls_shd - vlsm->shared_data_pool;
+}
+
+vls_shared_data_t *
+vls_shared_data_get (u32 shd_index)
+{
+  if (pool_is_free_index (vlsm->shared_data_pool, shd_index))
+    return 0;
+  return pool_elt_at_index (vlsm->shared_data_pool, shd_index);
+}
+
+static void
+vls_shared_data_free (u32 shd_index)
+{
+  vls_shared_data_t *vls_shd;
+
+  clib_rwlock_writer_lock (&vlsm->shared_data_lock);
+  vls_shd = vls_shared_data_get (shd_index);
+  clib_spinlock_free (&vls_shd->lock);
+  clib_bitmap_free (vls_shd->listeners);
+  vec_free (vls_shd->workers_subscribed);
+  pool_put (vlsm->shared_data_pool, vls_shd);
+  clib_rwlock_writer_unlock (&vlsm->shared_data_lock);
+}
+
+static inline void
+vls_shared_data_pool_rlock (void)
+{
+  clib_rwlock_reader_lock (&vlsm->shared_data_lock);
+}
+
+static inline void
+vls_shared_data_pool_runlock (void)
+{
+  clib_rwlock_reader_unlock (&vlsm->shared_data_lock);
+}
+
 static inline void
 vls_table_rlock (void)
 {
-  clib_rwlock_reader_lock (&vlsm->vls_table_lock);
+  if (vlsl->vls_mt_n_threads > 1)
+    clib_rwlock_reader_lock (&vlsm->vls_table_lock);
 }
 
 static inline void
 vls_table_runlock (void)
 {
-  clib_rwlock_reader_unlock (&vlsm->vls_table_lock);
+  if (vlsl->vls_mt_n_threads > 1)
+    clib_rwlock_reader_unlock (&vlsm->vls_table_lock);
 }
 
 static inline void
 vls_table_wlock (void)
 {
-  clib_rwlock_writer_lock (&vlsm->vls_table_lock);
+  if (vlsl->vls_mt_n_threads > 1)
+    clib_rwlock_writer_lock (&vlsm->vls_table_lock);
 }
 
 static inline void
 vls_table_wunlock (void)
 {
-  clib_rwlock_writer_unlock (&vlsm->vls_table_lock);
+  if (vlsl->vls_mt_n_threads > 1)
+    clib_rwlock_writer_unlock (&vlsm->vls_table_lock);
 }
 
 typedef enum
@@ -124,6 +205,26 @@ vls_mt_locks_init (void)
   pthread_mutex_init (&vlsl->vls_mt_spool_mlock, NULL);
 }
 
+u8
+vls_is_shared (vcl_locked_session_t * vls)
+{
+  return (vls->shared_data_index != ~0);
+}
+
+static inline void
+vls_lock (vcl_locked_session_t * vls)
+{
+  if ((vlsl->vls_mt_n_threads > 1) || vls_is_shared (vls))
+    clib_spinlock_lock (&vls->lock);
+}
+
+static inline void
+vls_unlock (vcl_locked_session_t * vls)
+{
+  if ((vlsl->vls_mt_n_threads > 1) || vls_is_shared (vls))
+    clib_spinlock_unlock (&vls->lock);
+}
+
 static inline vcl_session_handle_t
 vls_to_sh (vcl_locked_session_t * vls)
 {
@@ -139,19 +240,54 @@ vls_to_sh_tu (vcl_locked_session_t * vls)
   return sh;
 }
 
+static vls_worker_t *
+vls_worker_get_current (void)
+{
+  return pool_elt_at_index (vlsm->workers, vls_get_worker_index ());
+}
+
+static void
+vls_worker_alloc (void)
+{
+  vls_worker_t *wrk;
+
+  pool_get_zero (vlsm->workers, wrk);
+  wrk->wrk_index = vcl_get_worker_index ();
+}
+
+static void
+vls_worker_free (vls_worker_t * wrk)
+{
+  hash_free (wrk->session_index_to_vlsh_table);
+  pool_free (wrk->vls_pool);
+  pool_put (vlsm->workers, wrk);
+}
+
+static vls_worker_t *
+vls_worker_get (u32 wrk_index)
+{
+  if (pool_is_free_index (vlsm->workers, wrk_index))
+    return 0;
+  return pool_elt_at_index (vlsm->workers, wrk_index);
+}
+
 static vls_handle_t
 vls_alloc (vcl_session_handle_t sh)
 {
+  vls_worker_t *wrk = vls_worker_get_current ();
   vcl_locked_session_t *vls;
 
   vls_table_wlock ();
-  pool_get (vlsm->vls_pool, vls);
+
+  pool_get_zero (wrk->vls_pool, vls);
   vls->session_index = vppcom_session_index (sh);
   vls->worker_index = vppcom_session_worker (sh);
-  vls->vls_index = vls - vlsm->vls_pool;
-  hash_set (vlsm->session_index_to_vlsh_table, vls->session_index,
+  vls->vls_index = vls - wrk->vls_pool;
+  vls->shared_data_index = ~0;
+  hash_set (wrk->session_index_to_vlsh_table, vls->session_index,
 	    vls->vls_index);
   clib_spinlock_init (&vls->lock);
+
   vls_table_wunlock ();
   return vls->vls_index;
 }
@@ -159,28 +295,32 @@ vls_alloc (vcl_session_handle_t sh)
 static vcl_locked_session_t *
 vls_get (vls_handle_t vlsh)
 {
-  if (pool_is_free_index (vlsm->vls_pool, vlsh))
+  vls_worker_t *wrk = vls_worker_get_current ();
+  if (pool_is_free_index (wrk->vls_pool, vlsh))
     return 0;
-  return pool_elt_at_index (vlsm->vls_pool, vlsh);
+  return pool_elt_at_index (wrk->vls_pool, vlsh);
 }
 
 static void
 vls_free (vcl_locked_session_t * vls)
 {
+  vls_worker_t *wrk = vls_worker_get_current ();
+
   ASSERT (vls != 0);
-  hash_unset (vlsm->session_index_to_vlsh_table, vls->session_index);
+  hash_unset (wrk->session_index_to_vlsh_table, vls->session_index);
   clib_spinlock_free (&vls->lock);
-  pool_put (vlsm->vls_pool, vls);
+  pool_put (wrk->vls_pool, vls);
 }
 
 static vcl_locked_session_t *
 vls_get_and_lock (vls_handle_t vlsh)
 {
+  vls_worker_t *wrk = vls_worker_get_current ();
   vcl_locked_session_t *vls;
-  if (pool_is_free_index (vlsm->vls_pool, vlsh))
+  if (pool_is_free_index (wrk->vls_pool, vlsh))
     return 0;
-  vls = pool_elt_at_index (vlsm->vls_pool, vlsh);
-  clib_spinlock_lock (&vls->lock);
+  vls = pool_elt_at_index (wrk->vls_pool, vlsh);
+  vls_lock (vls);
   return vls;
 }
 
@@ -196,18 +336,6 @@ vls_get_w_dlock (vls_handle_t vlsh)
 }
 
 static inline void
-vls_lock (vcl_locked_session_t * vls)
-{
-  clib_spinlock_lock (&vls->lock);
-}
-
-static inline void
-vls_unlock (vcl_locked_session_t * vls)
-{
-  clib_spinlock_unlock (&vls->lock);
-}
-
-static inline void
 vls_get_and_unlock (vls_handle_t vlsh)
 {
   vcl_locked_session_t *vls;
@@ -224,6 +352,14 @@ vls_dunlock (vcl_locked_session_t * vls)
   vls_table_runlock ();
 }
 
+static vcl_locked_session_t *
+vls_session_get (vls_worker_t * wrk, u32 vls_index)
+{
+  if (pool_is_free_index (wrk->vls_pool, vls_index))
+    return 0;
+  return pool_elt_at_index (wrk->vls_pool, vls_index);
+}
+
 vcl_session_handle_t
 vlsh_to_sh (vls_handle_t vlsh)
 {
@@ -249,8 +385,9 @@ vlsh_to_session_index (vls_handle_t vlsh)
 vls_handle_t
 vls_si_to_vlsh (u32 session_index)
 {
+  vls_worker_t *wrk = vls_worker_get_current ();
   uword *vlshp;
-  vlshp = hash_get (vlsm->session_index_to_vlsh_table, session_index);
+  vlshp = hash_get (wrk->session_index_to_vlsh_table, session_index);
   return vlshp ? *vlshp : VLS_INVALID_HANDLE;
 }
 
@@ -267,31 +404,93 @@ vls_session_index_to_vlsh (uint32_t session_index)
 }
 
 u8
-vls_is_shared (vcl_locked_session_t * vls)
-{
-  return vec_len (vls->workers_subscribed);
-}
-
-u8
 vls_is_shared_by_wrk (vcl_locked_session_t * vls, u32 wrk_index)
 {
+  vls_shared_data_t *vls_shd;
   int i;
-  for (i = 0; i < vec_len (vls->workers_subscribed); i++)
-    if (vls->workers_subscribed[i] == wrk_index)
-      return 1;
+
+  if (vls->shared_data_index == ~0)
+    return 0;
+
+  vls_shared_data_pool_rlock ();
+
+  vls_shd = vls_shared_data_get (vls->shared_data_index);
+  clib_spinlock_lock (&vls_shd->lock);
+
+  for (i = 0; i < vec_len (vls_shd->workers_subscribed); i++)
+    if (vls_shd->workers_subscribed[i] == wrk_index)
+      {
+	clib_spinlock_unlock (&vls_shd->lock);
+	vls_shared_data_pool_runlock ();
+	return 1;
+      }
+  clib_spinlock_unlock (&vls_shd->lock);
+
+  vls_shared_data_pool_runlock ();
   return 0;
 }
 
 static void
 vls_listener_wrk_set (vcl_locked_session_t * vls, u32 wrk_index, u8 is_active)
 {
-  clib_bitmap_set (vls->listeners, wrk_index, is_active);
+  vls_shared_data_t *vls_shd;
+
+  if (vls->shared_data_index == ~0)
+    {
+      clib_warning ("not a shared session");
+      return;
+    }
+
+  vls_shared_data_pool_rlock ();
+
+  vls_shd = vls_shared_data_get (vls->shared_data_index);
+
+  clib_spinlock_lock (&vls_shd->lock);
+  clib_bitmap_set (vls_shd->listeners, wrk_index, is_active);
+  clib_spinlock_unlock (&vls_shd->lock);
+
+  vls_shared_data_pool_runlock ();
+}
+
+static u32
+vls_shared_get_owner (vcl_locked_session_t * vls)
+{
+  vls_shared_data_t *vls_shd;
+  u32 owner_wrk;
+
+  vls_shared_data_pool_rlock ();
+
+  vls_shd = vls_shared_data_get (vls->shared_data_index);
+  owner_wrk = vls_shd->owner_wrk_index;
+
+  vls_shared_data_pool_runlock ();
+
+  return owner_wrk;
 }
 
 static u8
 vls_listener_wrk_is_active (vcl_locked_session_t * vls, u32 wrk_index)
 {
-  return (clib_bitmap_get (vls->listeners, wrk_index) == 1);
+  vls_shared_data_t *vls_shd;
+  u8 is_set;
+
+  if (vls->shared_data_index == ~0)
+    {
+      clib_warning ("not a shared session");
+      return 0;
+    }
+
+  vls_shared_data_pool_rlock ();
+
+  vls_shd = vls_shared_data_get (vls->shared_data_index);
+
+  clib_spinlock_lock (&vls_shd->lock);
+  is_set = clib_bitmap_get (vls_shd->listeners, wrk_index);
+  clib_spinlock_unlock (&vls_shd->lock);
+
+  vls_shared_data_pool_runlock ();
+
+  return (is_set == 1);
 }
 
 static void
@@ -316,96 +515,199 @@ vls_listener_wrk_stop_listen (vcl_locked_session_t * vls, u32 wrk_index)
   vls_listener_wrk_set (vls, wrk_index, 0 /* is_active */ );
 }
 
+static int
+vls_shared_data_subscriber_position (vls_shared_data_t * vls_shd,
+				     u32 wrk_index)
+{
+  int i;
+
+  for (i = 0; i < vec_len (vls_shd->workers_subscribed); i++)
+    {
+      if (vls_shd->workers_subscribed[i] == wrk_index)
+	return i;
+    }
+  return -1;
+}
+
 int
 vls_unshare_session (vcl_locked_session_t * vls, vcl_worker_t * wrk)
 {
-  int i, do_disconnect;
+  vls_shared_data_t *vls_shd;
+  int do_disconnect;
+  u32 n_subscribers, pos;
   vcl_session_t *s;
 
+  ASSERT (vls->shared_data_index != ~0);
+
   s = vcl_session_get (wrk, vls->session_index);
   if (s->session_state == STATE_LISTEN)
     vls_listener_wrk_set (vls, wrk->wrk_index, 0 /* is_active */ );
 
-  for (i = 0; i < vec_len (vls->workers_subscribed); i++)
+  vls_shared_data_pool_rlock ();
+
+  vls_shd = vls_shared_data_get (vls->shared_data_index);
+  clib_spinlock_lock (&vls_shd->lock);
+
+  pos = vls_shared_data_subscriber_position (vls_shd, wrk->wrk_index);
+  if (pos < 0)
     {
-      if (vls->workers_subscribed[i] != wrk->wrk_index)
-	continue;
+      clib_warning ("worker %u not subscribed for vls %u", wrk->wrk_index,
+		    vls->worker_index);
+      goto done;
+    }
 
-      if (s->rx_fifo)
-	{
-	  svm_fifo_del_subscriber (s->rx_fifo, wrk->vpp_wrk_index);
-	  svm_fifo_del_subscriber (s->tx_fifo, wrk->vpp_wrk_index);
-	}
-      vec_del1 (vls->workers_subscribed, i);
-      do_disconnect = s->session_state == STATE_LISTEN;
-      vcl_session_cleanup (wrk, s, vcl_session_handle (s), do_disconnect);
+  /*
+   * Unsubscribe from share data and fifos
+   */
+  if (s->rx_fifo)
+    {
+      svm_fifo_del_subscriber (s->rx_fifo, wrk->vpp_wrk_index);
+      svm_fifo_del_subscriber (s->tx_fifo, wrk->vpp_wrk_index);
+    }
+  vec_del1 (vls_shd->workers_subscribed, pos);
+
+  /*
+   * Cleanup vcl state
+   */
+  n_subscribers = vec_len (vls_shd->workers_subscribed);
+  do_disconnect = s->session_state == STATE_LISTEN || !n_subscribers;
+  vcl_session_cleanup (wrk, s, vcl_session_handle (s), do_disconnect);
+
+  /*
+   * No subscriber left, cleanup shared data
+   */
+  if (!n_subscribers)
+    {
+      u32 shd_index = vls_shared_data_index (vls_shd);
+
+      clib_spinlock_unlock (&vls_shd->lock);
+      vls_shared_data_pool_runlock ();
+
+      vls_shared_data_free (shd_index);
+
+      /* All locks have been dropped */
       return 0;
     }
 
   /* Return, if this is not the owning worker */
-  if (vls->worker_index != wrk->wrk_index)
-    return 0;
+  if (vls_shd->owner_wrk_index != wrk->wrk_index)
+    goto done;
+
+  ASSERT (vec_len (vls_shd->workers_subscribed));
+
+  /*
+   *  Check if we can change owner or close
+   */
+  vls_shd->owner_wrk_index = vls_shd->workers_subscribed[0];
+  vcl_send_session_worker_update (wrk, s, vls_shd->owner_wrk_index);
+
+  /* XXX is this still needed? */
+  if (vec_len (vls_shd->workers_subscribed) > 1)
+    clib_warning ("more workers need to be updated");
+
+done:
+
+  clib_spinlock_unlock (&vls_shd->lock);
+  vls_shared_data_pool_runlock ();
+
+  return 0;
+}
+
+void
+vls_share_session (vcl_locked_session_t * vls, vls_worker_t * vls_wrk,
+		   vls_worker_t * vls_parent_wrk, vcl_worker_t * vcl_wrk)
+{
+  vcl_locked_session_t *parent_vls;
+  vls_shared_data_t *vls_shd;
+  vcl_session_t *s;
 
-  /* Check if we can change owner or close */
-  if (vec_len (vls->workers_subscribed))
+  s = vcl_session_get (vcl_wrk, vls->session_index);
+  if (!s)
     {
-      vls->worker_index = vls->workers_subscribed[0];
-      vec_del1 (vls->workers_subscribed, 0);
-      vcl_send_session_worker_update (wrk, s, vls->worker_index);
-      if (vec_len (vls->workers_subscribed))
-	clib_warning ("more workers need to be updated");
+      clib_warning ("wrk %u parent %u session %u vls %u NOT AVAILABLE",
+		    vcl_wrk->wrk_index, vls_parent_wrk->wrk_index,
+		    vls->session_index, vls->vls_index);
+      return;
+    }
+
+  /* Reinit session lock */
+  clib_spinlock_init (&vls->lock);
+
+  if (vls->shared_data_index != ~0)
+    {
+      vls_shared_data_pool_rlock ();
+      vls_shd = vls_shared_data_get (vls->shared_data_index);
     }
   else
     {
-      vcl_session_cleanup (wrk, s, vcl_session_handle (s),
-			   1 /* do_disconnect */ );
+      u32 vls_shd_index = vls_shared_data_alloc ();
+
+      vls_shared_data_pool_rlock ();
+
+      vls_shd = vls_shared_data_get (vls_shd_index);
+      vls_shd->owner_wrk_index = vls_parent_wrk->wrk_index;
+      vls->shared_data_index = vls_shd_index;
+
+      /* Update parent shared data */
+      parent_vls = vls_session_get (vls_parent_wrk, vls->vls_index);
+      parent_vls->shared_data_index = vls_shd_index;
+      vec_add1 (vls_shd->workers_subscribed, vls_parent_wrk->wrk_index);
     }
 
-  return 0;
-}
+  clib_spinlock_lock (&vls_shd->lock);
 
-void
-vls_share_vcl_session (vcl_worker_t * wrk, vcl_session_t * s)
-{
-  vcl_locked_session_t *vls;
+  vec_add1 (vls_shd->workers_subscribed, vls_wrk->wrk_index);
+
+  clib_spinlock_unlock (&vls_shd->lock);
+  vls_shared_data_pool_runlock ();
 
-  vls = vls_get (vls_si_to_vlsh (s->session_index));
-  if (!vls)
-    return;
-  vls_lock (vls);
-  vec_add1 (vls->workers_subscribed, wrk->wrk_index);
   if (s->rx_fifo)
     {
-      svm_fifo_add_subscriber (s->rx_fifo, wrk->vpp_wrk_index);
-      svm_fifo_add_subscriber (s->tx_fifo, wrk->vpp_wrk_index);
+      svm_fifo_add_subscriber (s->rx_fifo, vcl_wrk->vpp_wrk_index);
+      svm_fifo_add_subscriber (s->tx_fifo, vcl_wrk->vpp_wrk_index);
     }
   else if (s->session_state == STATE_LISTEN)
     {
       s->session_state = STATE_LISTEN_NO_MQ;
     }
+}
 
-  vls_unlock (vls);
+static void
+vls_share_sessions (vls_worker_t * vls_parent_wrk, vls_worker_t * vls_wrk)
+{
+  vcl_worker_t *vcl_wrk = vcl_worker_get (vls_wrk->wrk_index);
+  vcl_locked_session_t *vls;
+
+  /* *INDENT-OFF* */
+  pool_foreach (vls, vls_wrk->vls_pool, ({
+    vls_share_session (vls, vls_wrk, vls_parent_wrk, vcl_wrk);
+  }));
+  /* *INDENT-ON* */
 }
 
 void
 vls_worker_copy_on_fork (vcl_worker_t * parent_wrk)
 {
+  vls_worker_t *vls_wrk = vls_worker_get_current (), *vls_parent_wrk;
   vcl_worker_t *wrk = vcl_worker_get_current ();
-  vcl_session_t *s;
 
+  /*
+   * init vcl worker
+   */
   wrk->vpp_event_queues = vec_dup (parent_wrk->vpp_event_queues);
   wrk->sessions = pool_dup (parent_wrk->sessions);
   wrk->session_index_by_vpp_handles =
     hash_dup (parent_wrk->session_index_by_vpp_handles);
-  vls_table_rlock ();
 
-  /* *INDENT-OFF* */
-  pool_foreach (s, wrk->sessions, ({
-    vls_share_vcl_session (wrk, s);
-  }));
-  /* *INDENT-ON* */
+  /*
+   * init vls worker
+   */
+  vls_parent_wrk = vls_worker_get (parent_wrk->wrk_index);
+  vls_wrk->session_index_to_vlsh_table =
+    hash_dup (vls_parent_wrk->session_index_to_vlsh_table);
+  vls_wrk->vls_pool = pool_dup (vls_parent_wrk->vls_pool);
 
-  vls_table_runlock ();
+  vls_share_sessions (vls_parent_wrk, vls_wrk);
 }
 
 static void
@@ -620,6 +922,7 @@ vls_mp_checks (vcl_locked_session_t * vls, int is_add)
 {
   vcl_worker_t *wrk = vcl_worker_get_current ();
   vcl_session_t *s;
+  u32 owner_wrk;
 
   s = vcl_session_get (wrk, vls->session_index);
   switch (s->session_state)
@@ -627,8 +930,7 @@ vls_mp_checks (vcl_locked_session_t * vls, int is_add)
     case STATE_LISTEN:
       if (is_add)
 	{
-	  if (vls->worker_index == wrk->wrk_index)
-	    vls_listener_wrk_set (vls, wrk->wrk_index, 1 /* is_active */ );
+	  vls_listener_wrk_set (vls, vls->worker_index, 1 /* is_active */ );
 	  break;
 	}
       vls_listener_wrk_stop_listen (vls, vls->worker_index);
@@ -647,8 +949,9 @@ vls_mp_checks (vcl_locked_session_t * vls, int is_add)
        * that it is fine to listen and not accept new sessions for a
        * given listener. Without it, we would accumulate unhandled
        * accepts on the passive worker message queue. */
-      if (!vls_listener_wrk_is_active (vls, vls->worker_index))
-	vls_listener_wrk_stop_listen (vls, vls->worker_index);
+      owner_wrk = vls_shared_get_owner (vls);
+      if (!vls_listener_wrk_is_active (vls, owner_wrk))
+	vls_listener_wrk_stop_listen (vls, owner_wrk);
       break;
     default:
       break;
@@ -713,17 +1016,12 @@ vls_close (vls_handle_t vlsh)
     }
 
   vls_mt_guard (0, VLS_MT_OP_SPOOL);
+
   if (vls_is_shared (vls))
-    {
-      /* At least two workers share the session so vls won't be freed */
-      vls_unshare_session (vls, vcl_worker_get_current ());
-      vls_unlock (vls);
-      vls_mt_unguard ();
-      vls_table_wunlock ();
-      return VPPCOM_OK;
-    }
+    rv = vls_unshare_session (vls, vcl_worker_get_current ());
+  else
+    rv = vppcom_session_close (vls_to_sh (vls));
 
-  rv = vppcom_session_close (vls_to_sh (vls));
   vls_free (vls);
   vls_mt_unguard ();
 
@@ -873,7 +1171,6 @@ vls_unshare_vcl_worker_sessions (vcl_worker_t * wrk)
 
   current_wrk = vcl_get_worker_index ();
   is_current = current_wrk == wrk->wrk_index;
-  vls_table_wlock ();
 
   /* *INDENT-OFF* */
   pool_foreach (s, wrk->sessions, ({
@@ -882,17 +1179,19 @@ vls_unshare_vcl_worker_sessions (vcl_worker_t * wrk)
       vls_unshare_session (vls, wrk);
   }));
   /* *INDENT-ON* */
-
-  vls_table_wunlock ();
 }
 
 static void
 vls_cleanup_vcl_worker (vcl_worker_t * wrk)
 {
+  vls_worker_t *vls_wrk = vls_worker_get (wrk->wrk_index);
+
   /* Unshare sessions and also cleanup worker since child may have
    * called _exit () and therefore vcl may not catch the event */
   vls_unshare_vcl_worker_sessions (wrk);
   vcl_worker_cleanup (wrk, 1 /* notify vpp */ );
+
+  vls_worker_free (vls_wrk);
 }
 
 static void
@@ -996,7 +1295,7 @@ vls_app_fork_child_handler (void)
 	parent_wrk_index);
 
   /*
-   * Allocate worker
+   * Allocate worker vcl
    */
   vcl_set_worker_index (~0);
   if (!vcl_worker_alloc_and_init ())
@@ -1018,6 +1317,11 @@ vls_app_fork_child_handler (void)
     }
 
   /*
+   * Allocate/initialize vls worker
+   */
+  vls_worker_alloc ();
+
+  /*
    * Register worker with vpp and share sessions
    */
   vcl_worker_register_with_vpp ();
@@ -1047,8 +1351,11 @@ vls_app_fork_parent_handler (void)
 void
 vls_app_exit (void)
 {
+  vls_worker_t *wrk = vls_worker_get_current ();
+
   /* Unshare the sessions. VCL will clean up the worker */
   vls_unshare_vcl_worker_sessions (vcl_worker_get_current ());
+  vls_worker_free (wrk);
 }
 
 int
@@ -1058,12 +1365,17 @@ vls_app_create (char *app_name)
 
   if ((rv = vppcom_app_create (app_name)))
     return rv;
+
   vlsm = clib_mem_alloc (sizeof (vls_main_t));
   clib_memset (vlsm, 0, sizeof (*vlsm));
   clib_rwlock_init (&vlsm->vls_table_lock);
+  clib_rwlock_init (&vlsm->shared_data_lock);
+  pool_alloc (vlsm->workers, vcm->cfg.max_workers);
+
   pthread_atfork (vls_app_pre_fork, vls_app_fork_parent_handler,
 		  vls_app_fork_child_handler);
   atexit (vls_app_exit);
+  vls_worker_alloc ();
   vlsl->vls_wrk_index = vcl_get_worker_index ();
   vls_mt_locks_init ();
   return VPPCOM_OK;
diff --git a/src/vcl/vcl_private.h b/src/vcl/vcl_private.h
index b50bad26b90..3866563435b 100644
--- a/src/vcl/vcl_private.h
+++ b/src/vcl/vcl_private.h
@@ -374,7 +374,8 @@ vcl_session_alloc (vcl_worker_t * wrk)
 static inline void
 vcl_session_free (vcl_worker_t * wrk, vcl_session_t * s)
 {
-  VDBG (0, "session %u [0x%llx] removed", s->session_index, s->vpp_handle);
+  /* Debug level set to 1 to avoid debug messages while ldp is cleaning up */
+  VDBG (1, "session %u [0x%llx] removed", s->session_index, s->vpp_handle);
   pool_put (wrk->sessions, s);
 }