X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvcl%2Fvcl_locked.c;h=ae9c9762dc1b40eb2c3b29913b34e9885c8a033a;hb=07063b8ea;hp=c6c79cdd470eb8baf7f43492ea781922a4253be1;hpb=f9240dc9207b677038183ca29888d4be89bb88d5;p=vpp.git

diff --git a/src/vcl/vcl_locked.c b/src/vcl/vcl_locked.c
index c6c79cdd470..ae9c9762dc1 100644
--- a/src/vcl/vcl_locked.c
+++ b/src/vcl/vcl_locked.c
@@ -16,48 +16,213 @@
 #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 flags;
-  u32 *workers_subscribed;
+  u32 shared_data_index;
 } vcl_locked_session_t;
 
-typedef struct vcl_main_
+typedef struct vls_worker_
 {
   vcl_locked_session_t *vls_pool;
-  clib_rwlock_t vls_table_lock;
   uword *session_index_to_vlsh_table;
+  u32 wrk_index;
+} vls_worker_t;
+
+typedef struct vls_local_
+{
+  int vls_wrk_index;
+  volatile int vls_mt_n_threads;
+  pthread_mutex_t vls_mt_mq_mlock;
+  pthread_mutex_t vls_mt_spool_mlock;
+  volatile u8 select_mp_check;
+  volatile u8 epoll_mp_check;
+} vls_process_local_t;
+
+static vls_process_local_t vls_local;
+static vls_process_local_t *vlsl = &vls_local;
+
+typedef struct vls_main_
+{
+  vls_worker_t *workers;
+  clib_rwlock_t vls_table_lock;
+  /** 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 vls_main;
-vls_main_t *vlsm = &vls_main;
+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
+{
+  VLS_MT_OP_READ,
+  VLS_MT_OP_WRITE,
+  VLS_MT_OP_SPOOL,
+  VLS_MT_OP_XPOLL,
+} vls_mt_ops_t;
+
+typedef enum
+{
+  VLS_MT_LOCK_MQ = 1 << 0,
+  VLS_MT_LOCK_SPOOL = 1 << 1
+} vls_mt_lock_type_t;
+
+static void
+vls_mt_add (void)
+{
+  vlsl->vls_mt_n_threads += 1;
+  vcl_set_worker_index (vlsl->vls_wrk_index);
+}
+
+static inline void
+vls_mt_mq_lock (void)
+{
+  pthread_mutex_lock (&vlsl->vls_mt_mq_mlock);
+}
+
+static inline void
+vls_mt_mq_unlock (void)
+{
+  pthread_mutex_unlock (&vlsl->vls_mt_mq_mlock);
+}
+
+static inline void
+vls_mt_spool_lock (void)
+{
+  pthread_mutex_lock (&vlsl->vls_mt_spool_mlock);
+}
+
+static inline void
+vls_mt_create_unlock (void)
+{
+  pthread_mutex_unlock (&vlsl->vls_mt_spool_mlock);
+}
+
+static void
+vls_mt_locks_init (void)
+{
+  pthread_mutex_init (&vlsl->vls_mt_mq_mlock, NULL);
+  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
@@ -75,19 +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;
 }
@@ -95,28 +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 * fde)
+vls_free (vcl_locked_session_t * vls)
 {
-  ASSERT (fde != 0);
-  hash_unset (vlsm->session_index_to_vlsh_table, fde->session_index);
-  clib_spinlock_free (&fde->lock);
-  pool_put (vlsm->vls_pool, fde);
+  vls_worker_t *wrk = vls_worker_get_current ();
+
+  ASSERT (vls != 0);
+  hash_unset (wrk->session_index_to_vlsh_table, vls->session_index);
+  clib_spinlock_free (&vls->lock);
+  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;
 }
 
@@ -131,12 +335,6 @@ vls_get_w_dlock (vls_handle_t vlsh)
   return vls;
 }
 
-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)
 {
@@ -154,97 +352,433 @@ vls_dunlock (vcl_locked_session_t * vls)
   vls_table_runlock ();
 }
 
-static void
-vls_get_and_free (vls_handle_t vlsh)
+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)
 {
   vcl_locked_session_t *vls;
+  int rv;
 
-  vls_table_wlock ();
-  vls = vls_get (vlsh);
-  vls_free (vls);
-  vls_table_wunlock ();
+  vls = vls_get_w_dlock (vlsh);
+  if (!vls)
+    return INVALID_SESSION_ID;
+  rv = vls_to_sh (vls);
+  vls_dunlock (vls);
+  return rv;
+}
+
+vcl_session_handle_t
+vlsh_to_session_index (vls_handle_t vlsh)
+{
+  vcl_session_handle_t sh;
+  sh = vlsh_to_sh (vlsh);
+  return vppcom_session_index (sh);
+}
+
+vls_handle_t
+vls_si_to_vlsh (u32 session_index)
+{
+  vls_worker_t *wrk = vls_worker_get_current ();
+  uword *vlshp;
+  vlshp = hash_get (wrk->session_index_to_vlsh_table, session_index);
+  return vlshp ? *vlshp : VLS_INVALID_HANDLE;
+}
+
+vls_handle_t
+vls_session_index_to_vlsh (uint32_t session_index)
+{
+  vls_handle_t vlsh;
+
+  vls_table_rlock ();
+  vlsh = vls_si_to_vlsh (session_index);
+  vls_table_runlock ();
+
+  return vlsh;
 }
 
 u8
-vls_is_shared (vcl_locked_session_t * vls)
+vls_is_shared_by_wrk (vcl_locked_session_t * vls, u32 wrk_index)
 {
-  return vec_len (vls->workers_subscribed);
+  vls_shared_data_t *vls_shd;
+  int i;
+
+  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;
 }
 
-int
-vls_unshare_session (vcl_locked_session_t * vls)
+static void
+vls_listener_wrk_set (vcl_locked_session_t * vls, u32 wrk_index, u8 is_active)
 {
-  vcl_worker_t *wrk = vcl_worker_get_current ();
+  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)
+{
+  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
+vls_listener_wrk_start_listen (vcl_locked_session_t * vls, u32 wrk_index)
+{
+  vppcom_session_listen (vls_to_sh (vls), ~0);
+  vls_listener_wrk_set (vls, wrk_index, 1 /* is_active */ );
+}
+
+static void
+vls_listener_wrk_stop_listen (vcl_locked_session_t * vls, u32 wrk_index)
+{
+  vcl_worker_t *wrk;
   vcl_session_t *s;
+
+  wrk = vcl_worker_get (wrk_index);
+  s = vcl_session_get (wrk, vls->session_index);
+  if (s->session_state != STATE_LISTEN)
+    return;
+  vcl_send_session_unlisten (wrk, s);
+  s->session_state = STATE_LISTEN_NO_MQ;
+  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->workers_subscribed); i++)
+  for (i = 0; i < vec_len (vls_shd->workers_subscribed); i++)
     {
-      if (vls->workers_subscribed[i] != wrk->wrk_index)
-	continue;
+      if (vls_shd->workers_subscribed[i] == wrk_index)
+	return i;
+    }
+  return -1;
+}
 
-      s = vcl_session_get (wrk, vls->session_index);
-      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);
-      vcl_session_cleanup (wrk, s, vcl_session_handle (s),
-			   0 /* do_disconnect */ );
-      return 0;
+int
+vls_unshare_session (vcl_locked_session_t * vls, vcl_worker_t * wrk)
+{
+  vls_shared_data_t *vls_shd;
+  int do_disconnect, pos;
+  u32 n_subscribers;
+  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 */ );
+
+  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)
+    {
+      clib_warning ("worker %u not subscribed for vls %u", wrk->wrk_index,
+		    vls->worker_index);
+      goto done;
     }
 
-  /* Assumption is that unshare is only called if session is shared.
-   * So shared_workers must be non-empty if the worker is the owner */
-  if (vls->worker_index == wrk->wrk_index)
+  /*
+   * Unsubscribe from share data and fifos
+   */
+  if (s->rx_fifo)
     {
-      s = vcl_session_get (wrk, vls->session_index);
-      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");
+      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_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_vcl_session (vcl_worker_t * wrk, vcl_session_t * s)
+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 *vls;
+  vcl_locked_session_t *parent_vls;
+  vls_shared_data_t *vls_shd;
+  vcl_session_t *s;
+
+  s = vcl_session_get (vcl_wrk, vls->session_index);
+  if (!s)
+    {
+      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
+    {
+      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);
+    }
+
+  clib_spinlock_lock (&vls_shd->lock);
+
+  vec_add1 (vls_shd->workers_subscribed, vls_wrk->wrk_index);
+
+  clib_spinlock_unlock (&vls_shd->lock);
+  vls_shared_data_pool_runlock ();
 
-  vls = vls_get_w_dlock (vls_session_index_to_vlsh (s->session_index));
-  if (!vls)
-    return;
-  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);
     }
-  vls_dunlock (vls);
+  else if (s->session_state == STATE_LISTEN)
+    {
+      s->session_state = STATE_LISTEN_NO_MQ;
+    }
+}
+
+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);
 
-  /* *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_share_sessions (vls_parent_wrk, vls_wrk);
 }
 
+static void
+vls_mt_acq_locks (vcl_locked_session_t * vls, vls_mt_ops_t op, int *locks_acq)
+{
+  vcl_worker_t *wrk = vcl_worker_get_current ();
+  vcl_session_t *s = 0;
+  int is_nonblk = 0;
+
+  if (vls)
+    {
+      s = vcl_session_get (wrk, vls->session_index);
+      if (PREDICT_FALSE (!s))
+	return;
+      is_nonblk = VCL_SESS_ATTR_TEST (s->attr, VCL_SESS_ATTR_NONBLOCK);
+    }
+
+  switch (op)
+    {
+    case VLS_MT_OP_READ:
+      if (!is_nonblk)
+	is_nonblk = vcl_session_read_ready (s) != 0;
+      if (!is_nonblk)
+	{
+	  vls_mt_mq_lock ();
+	  *locks_acq |= VLS_MT_LOCK_MQ;
+	}
+      break;
+    case VLS_MT_OP_WRITE:
+      ASSERT (s);
+      if (!is_nonblk)
+	is_nonblk = vcl_session_write_ready (s) != 0;
+      if (!is_nonblk)
+	{
+	  vls_mt_mq_lock ();
+	  *locks_acq |= VLS_MT_LOCK_MQ;
+	}
+      break;
+    case VLS_MT_OP_XPOLL:
+      vls_mt_mq_lock ();
+      *locks_acq |= VLS_MT_LOCK_MQ;
+      break;
+    case VLS_MT_OP_SPOOL:
+      vls_mt_spool_lock ();
+      *locks_acq |= VLS_MT_LOCK_SPOOL;
+      break;
+    default:
+      break;
+    }
+}
+
+static void
+vls_mt_rel_locks (int locks_acq)
+{
+  if (locks_acq & VLS_MT_LOCK_MQ)
+    vls_mt_mq_unlock ();
+  if (locks_acq & VLS_MT_LOCK_SPOOL)
+    vls_mt_create_unlock ();
+}
+
+#define vls_mt_guard(_vls, _op)				\
+  int _locks_acq = 0;					\
+  if (PREDICT_FALSE (vcl_get_worker_index () == ~0))	\
+    vls_mt_add ();					\
+  if (PREDICT_FALSE (vlsl->vls_mt_n_threads > 1))	\
+    vls_mt_acq_locks (_vls, _op, &_locks_acq);		\
+
+#define vls_mt_unguard()				\
+  if (PREDICT_FALSE (_locks_acq))			\
+    vls_mt_rel_locks (_locks_acq)
+
 int
 vls_write (vls_handle_t vlsh, void *buf, size_t nbytes)
 {
@@ -253,7 +787,10 @@ vls_write (vls_handle_t vlsh, void *buf, size_t nbytes)
 
   if (!(vls = vls_get_w_dlock (vlsh)))
     return VPPCOM_EBADFD;
+
+  vls_mt_guard (vls, VLS_MT_OP_WRITE);
   rv = vppcom_session_write (vls_to_sh_tu (vls), buf, nbytes);
+  vls_mt_unguard ();
   vls_get_and_unlock (vlsh);
   return rv;
 }
@@ -266,7 +803,9 @@ vls_write_msg (vls_handle_t vlsh, void *buf, size_t nbytes)
 
   if (!(vls = vls_get_w_dlock (vlsh)))
     return VPPCOM_EBADFD;
+  vls_mt_guard (vls, VLS_MT_OP_WRITE);
   rv = vppcom_session_write_msg (vls_to_sh_tu (vls), buf, nbytes);
+  vls_mt_unguard ();
   vls_get_and_unlock (vlsh);
   return rv;
 }
@@ -280,7 +819,9 @@ vls_sendto (vls_handle_t vlsh, void *buf, int buflen, int flags,
 
   if (!(vls = vls_get_w_dlock (vlsh)))
     return VPPCOM_EBADFD;
+  vls_mt_guard (vls, VLS_MT_OP_WRITE);
   rv = vppcom_session_sendto (vls_to_sh_tu (vls), buf, buflen, flags, ep);
+  vls_mt_unguard ();
   vls_get_and_unlock (vlsh);
   return rv;
 }
@@ -293,7 +834,9 @@ vls_read (vls_handle_t vlsh, void *buf, size_t nbytes)
 
   if (!(vls = vls_get_w_dlock (vlsh)))
     return VPPCOM_EBADFD;
+  vls_mt_guard (vls, VLS_MT_OP_READ);
   rv = vppcom_session_read (vls_to_sh_tu (vls), buf, nbytes);
+  vls_mt_unguard ();
   vls_get_and_unlock (vlsh);
   return rv;
 }
@@ -307,8 +850,10 @@ vls_recvfrom (vls_handle_t vlsh, void *buffer, uint32_t buflen, int flags,
 
   if (!(vls = vls_get_w_dlock (vlsh)))
     return VPPCOM_EBADFD;
+  vls_mt_guard (vls, VLS_MT_OP_READ);
   rv = vppcom_session_recvfrom (vls_to_sh_tu (vls), buffer, buflen, flags,
 				ep);
+  vls_mt_unguard ();
   vls_get_and_unlock (vlsh);
   return rv;
 }
@@ -319,6 +864,9 @@ vls_attr (vls_handle_t vlsh, uint32_t op, void *buffer, uint32_t * buflen)
   vcl_locked_session_t *vls;
   int rv;
 
+  if (PREDICT_FALSE (vcl_get_worker_index () == ~0))
+    vls_mt_add ();
+
   if (!(vls = vls_get_w_dlock (vlsh)))
     return VPPCOM_EBADFD;
   rv = vppcom_session_attr (vls_to_sh_tu (vls), op, buffer, buflen);
@@ -347,7 +895,9 @@ vls_listen (vls_handle_t vlsh, int q_len)
 
   if (!(vls = vls_get_w_dlock (vlsh)))
     return VPPCOM_EBADFD;
+  vls_mt_guard (vls, VLS_MT_OP_XPOLL);
   rv = vppcom_session_listen (vls_to_sh_tu (vls), q_len);
+  vls_mt_unguard ();
   vls_get_and_unlock (vlsh);
   return rv;
 }
@@ -360,11 +910,54 @@ vls_connect (vls_handle_t vlsh, vppcom_endpt_t * server_ep)
 
   if (!(vls = vls_get_w_dlock (vlsh)))
     return VPPCOM_EBADFD;
+  vls_mt_guard (vls, VLS_MT_OP_XPOLL);
   rv = vppcom_session_connect (vls_to_sh_tu (vls), server_ep);
+  vls_mt_unguard ();
   vls_get_and_unlock (vlsh);
   return rv;
 }
 
+static inline void
+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)
+    {
+    case STATE_LISTEN:
+      if (is_add)
+	{
+	  vls_listener_wrk_set (vls, vls->worker_index, 1 /* is_active */ );
+	  break;
+	}
+      vls_listener_wrk_stop_listen (vls, vls->worker_index);
+      break;
+    case STATE_LISTEN_NO_MQ:
+      if (!is_add)
+	break;
+
+      /* Register worker as listener */
+      vls_listener_wrk_start_listen (vls, wrk->wrk_index);
+
+      /* If owner worker did not attempt to accept/xpoll on the session,
+       * force a listen stop for it, since it may not be interested in
+       * accepting new sessions.
+       * This is pretty much a hack done to give app workers the illusion
+       * 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. */
+      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;
+    }
+}
+
 vls_handle_t
 vls_accept (vls_handle_t listener_vlsh, vppcom_endpt_t * ep, int flags)
 {
@@ -374,7 +967,11 @@ vls_accept (vls_handle_t listener_vlsh, vppcom_endpt_t * ep, int flags)
 
   if (!(vls = vls_get_w_dlock (listener_vlsh)))
     return VPPCOM_EBADFD;
+  if (vcl_n_workers () > 1)
+    vls_mp_checks (vls, 1 /* is_add */ );
+  vls_mt_guard (vls, VLS_MT_OP_SPOOL);
   sh = vppcom_session_accept (vls_to_sh_tu (vls), ep, flags);
+  vls_mt_unguard ();
   vls_get_and_unlock (listener_vlsh);
   if (sh < 0)
     return sh;
@@ -390,7 +987,9 @@ vls_create (uint8_t proto, uint8_t is_nonblocking)
   vcl_session_handle_t sh;
   vls_handle_t vlsh;
 
+  vls_mt_guard (0, VLS_MT_OP_SPOOL);
   sh = vppcom_session_create (proto, is_nonblocking);
+  vls_mt_unguard ();
   if (sh == INVALID_SESSION_ID)
     return VLS_INVALID_HANDLE;
 
@@ -405,28 +1004,29 @@ int
 vls_close (vls_handle_t vlsh)
 {
   vcl_locked_session_t *vls;
-  vcl_session_handle_t sh;
   int rv;
 
-  if (!(vls = vls_get_w_dlock (vlsh)))
-    return VPPCOM_EBADFD;
+  vls_table_wlock ();
 
-  if (vls_is_shared (vls))
+  vls = vls_get_and_lock (vlsh);
+  if (!vls)
     {
-      vls_unshare_session (vls);
-      vls_dunlock (vls);
-      return VPPCOM_OK;
+      vls_table_wunlock ();
+      return VPPCOM_EBADFD;
     }
 
-  sh = vls_to_sh (vls);
-  if ((rv = vppcom_session_close (sh)))
-    {
-      vls_dunlock (vls);
-      return rv;
-    }
+  vls_mt_guard (0, VLS_MT_OP_SPOOL);
+
+  if (vls_is_shared (vls))
+    rv = vls_unshare_session (vls, vcl_worker_get_current ());
+  else
+    rv = vppcom_session_close (vls_to_sh (vls));
+
+  vls_free (vls);
+  vls_mt_unguard ();
+
+  vls_table_wunlock ();
 
-  vls_dunlock (vls);
-  vls_get_and_free (vlsh);
   return rv;
 }
 
@@ -436,6 +1036,9 @@ vls_epoll_create (void)
   vcl_session_handle_t sh;
   vls_handle_t vlsh;
 
+  if (PREDICT_FALSE (vcl_get_worker_index () == ~0))
+    vls_mt_add ();
+
   sh = vppcom_epoll_create ();
   if (sh == INVALID_SESSION_ID)
     return VLS_INVALID_HANDLE;
@@ -447,6 +1050,22 @@ vls_epoll_create (void)
   return vlsh;
 }
 
+static void
+vls_epoll_ctl_mp_checks (vcl_locked_session_t * vls, int op)
+{
+  if (vcl_n_workers () <= 1)
+    {
+      vlsl->epoll_mp_check = 1;
+      return;
+    }
+
+  if (op == EPOLL_CTL_MOD)
+    return;
+
+  vlsl->epoll_mp_check = 1;
+  vls_mp_checks (vls, op == EPOLL_CTL_ADD);
+}
+
 int
 vls_epoll_ctl (vls_handle_t ep_vlsh, int op, vls_handle_t vlsh,
 	       struct epoll_event *event)
@@ -460,6 +1079,10 @@ vls_epoll_ctl (vls_handle_t ep_vlsh, int op, vls_handle_t vlsh,
   vls = vls_get_and_lock (vlsh);
   ep_sh = vls_to_sh (ep_vls);
   sh = vls_to_sh (vls);
+
+  if (PREDICT_FALSE (!vlsl->epoll_mp_check))
+    vls_epoll_ctl_mp_checks (vls, op);
+
   vls_table_runlock ();
 
   rv = vppcom_epoll_ctl (ep_sh, op, sh, event);
@@ -482,46 +1105,93 @@ vls_epoll_wait (vls_handle_t ep_vlsh, struct epoll_event *events,
 
   if (!(vls = vls_get_w_dlock (ep_vlsh)))
     return VPPCOM_EBADFD;
+  vls_mt_guard (0, VLS_MT_OP_XPOLL);
   rv = vppcom_epoll_wait (vls_to_sh_tu (vls), events, maxevents,
 			  wait_for_time);
+  vls_mt_unguard ();
   vls_get_and_unlock (ep_vlsh);
   return rv;
 }
 
-vcl_session_handle_t
-vlsh_to_sh (vls_handle_t vlsh)
+static void
+vls_select_mp_checks (vcl_si_set * read_map)
 {
   vcl_locked_session_t *vls;
+  vcl_worker_t *wrk;
+  vcl_session_t *s;
+  u32 si;
+
+  if (vcl_n_workers () <= 1)
+    {
+      vlsl->select_mp_check = 1;
+      return;
+    }
+
+  if (!read_map)
+    return;
+
+  vlsl->select_mp_check = 1;
+  wrk = vcl_worker_get_current ();
+
+  /* *INDENT-OFF* */
+  clib_bitmap_foreach (si, read_map, ({
+    s = vcl_session_get (wrk, si);
+    if (s->session_state == STATE_LISTEN)
+      {
+	vls = vls_get (vls_session_index_to_vlsh (si));
+	vls_mp_checks (vls, 1 /* is_add */);
+      }
+  }));
+  /* *INDENT-ON* */
+}
+
+int
+vls_select (int n_bits, vcl_si_set * read_map, vcl_si_set * write_map,
+	    vcl_si_set * except_map, double wait_for_time)
+{
   int rv;
 
-  vls = vls_get_w_dlock (vlsh);
-  if (!vls)
-    return INVALID_SESSION_ID;
-  rv = vls_to_sh (vls);
-  vls_dunlock (vls);
+  vls_mt_guard (0, VLS_MT_OP_XPOLL);
+  if (PREDICT_FALSE (!vlsl->select_mp_check))
+    vls_select_mp_checks (read_map);
+  rv = vppcom_select (n_bits, read_map, write_map, except_map, wait_for_time);
+  vls_mt_unguard ();
   return rv;
 }
 
-vcl_session_handle_t
-vlsh_to_session_index (vls_handle_t vlsh)
+static void
+vls_unshare_vcl_worker_sessions (vcl_worker_t * wrk)
 {
-  vcl_session_handle_t sh;
-  sh = vlsh_to_sh (vlsh);
-  return vppcom_session_index (sh);
+  u32 current_wrk, is_current;
+  vcl_locked_session_t *vls;
+  vcl_session_t *s;
+
+  if (pool_elts (vcm->workers) <= 1)
+    return;
+
+  current_wrk = vcl_get_worker_index ();
+  is_current = current_wrk == wrk->wrk_index;
+
+  /* *INDENT-OFF* */
+  pool_foreach (s, wrk->sessions, ({
+    vls = vls_get (vls_si_to_vlsh (s->session_index));
+    if (vls && (is_current || vls_is_shared_by_wrk (vls, current_wrk)))
+      vls_unshare_session (vls, wrk);
+  }));
+  /* *INDENT-ON* */
 }
 
-vls_handle_t
-vls_session_index_to_vlsh (uint32_t session_index)
+static void
+vls_cleanup_vcl_worker (vcl_worker_t * wrk)
 {
-  vls_handle_t vlsh;
-  uword *vlshp;
+  vls_worker_t *vls_wrk = vls_worker_get (wrk->wrk_index);
 
-  vls_table_rlock ();
-  vlshp = hash_get (vlsm->session_index_to_vlsh_table, session_index);
-  vlsh = vlshp ? *vlshp : VLS_INVALID_HANDLE;
-  vls_table_runlock ();
+  /* 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 */ );
 
-  return vlsh;
+  vls_worker_free (vls_wrk);
 }
 
 static void
@@ -542,8 +1212,8 @@ vls_cleanup_forked_child (vcl_worker_t * wrk, vcl_worker_t * child_wrk)
 	    vls_cleanup_forked_child (child_wrk, sub_child);
 	}
     }
-  vcl_worker_cleanup (child_wrk, 1 /* notify vpp */ );
-  VDBG (0, "Cleaned up wrk %u", child_wrk->wrk_index);
+  vls_cleanup_vcl_worker (child_wrk);
+  VDBG (0, "Cleaned up forked child wrk %u", child_wrk->wrk_index);
   wrk->forked_child = ~0;
 }
 
@@ -625,7 +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 ())
@@ -646,6 +1316,11 @@ vls_app_fork_child_handler (void)
       return;
     }
 
+  /*
+   * Allocate/initialize vls worker
+   */
+  vls_worker_alloc ();
+
   /*
    * Register worker with vpp and share sessions
    */
@@ -654,6 +1329,13 @@ vls_app_fork_child_handler (void)
   vls_worker_copy_on_fork (parent_wrk);
   parent_wrk->forked_child = vcl_get_worker_index ();
 
+  /* Reset number of threads and set wrk index */
+  vlsl->vls_mt_n_threads = 0;
+  vlsl->vls_wrk_index = vcl_get_worker_index ();
+  vlsl->select_mp_check = 0;
+  vlsl->epoll_mp_check = 0;
+  vls_mt_locks_init ();
+
   VDBG (0, "forked child main worker initialized");
   vcm->forking = 0;
 }
@@ -666,15 +1348,36 @@ 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
 vls_app_create (char *app_name)
 {
   int rv;
+
   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;
 }