text: /*
   * Copyright (c) 2017-2019 Cisco and/or its affiliates.
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <vnet/session/segment_manager.h>
  #include <vnet/session/session.h>
  #include <vnet/session/application.h>
  
  typedef struct segment_manager_main_
  {
    segment_manager_t *segment_managers;	/**< Pool of segment managers */
    clib_valloc_main_t va_allocator;	/**< Virtual address allocator */
    u32 seg_name_counter;			/**< Counter for segment names */
  
    /*
     * Configuration
     */
    u32 default_fifo_size;		/**< default rx/tx fifo size */
    u32 default_segment_size;		/**< default fifo segment size */
    u32 default_app_mq_size;		/**< default app msg q size */
  } segment_manager_main_t;
  
  static segment_manager_main_t sm_main;
  
  #define segment_manager_foreach_segment_w_lock(VAR, SM, BODY)		\
  do {									\
      clib_rwlock_reader_lock (&(SM)->segments_rwlock);			\
      pool_foreach((VAR), ((SM)->segments), (BODY));			\
      clib_rwlock_reader_unlock (&(SM)->segments_rwlock);			\
  } while (0)
  
  static segment_manager_props_t *
  segment_manager_properties_get (segment_manager_t * sm)
  {
    app_worker_t *app_wrk = app_worker_get (sm->app_wrk_index);
    return application_get_segment_manager_properties (app_wrk->app_index);
  }
  
  segment_manager_props_t *
  segment_manager_props_init (segment_manager_props_t * props)
  {
    props->add_segment_size = sm_main.default_segment_size;
    props->rx_fifo_size = sm_main.default_fifo_size;
    props->tx_fifo_size = sm_main.default_fifo_size;
    props->evt_q_size = sm_main.default_app_mq_size;
    props->n_slices = vlib_num_workers () + 1;
    return props;
  }
  
  static u8
  segment_manager_app_detached (segment_manager_t * sm)
  {
    return (sm->app_wrk_index == SEGMENT_MANAGER_INVALID_APP_INDEX);
  }
  
  void
  segment_manager_app_detach (segment_manager_t * sm)
  {
    sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
  }
  
  always_inline u32
  segment_manager_segment_index (segment_manager_t * sm, fifo_segment_t * seg)
  {
    return (seg - sm->segments);
  }
  
  /**
   * Adds segment to segment manager's pool
   *
   * If needed a writer's lock is acquired before allocating a new segment
   * to avoid affecting any of the segments pool readers.
   */
  int
  segment_manager_add_segment (segment_manager_t * sm, uword segment_size)
  {
    uword baseva = (uword) ~ 0ULL, alloc_size, page_size;
    u32 rnd_margin = 128 << 10, fs_index = ~0;
    segment_manager_main_t *smm = &sm_main;
    segment_manager_props_t *props;
    fifo_segment_t *fs;
    u8 *seg_name;
    int rv;
  
    props = segment_manager_properties_get (sm);
  
    /* Not configured for addition of new segments and not first */
    if (!props->add_segment && !segment_size)
      {
        clib_warning ("cannot allocate new segment");
        return VNET_API_ERROR_INVALID_VALUE;
      }
  
    /*
     * Allocate fifo segment and grab lock if needed
     */
    if (vlib_num_workers ())
      clib_rwlock_writer_lock (&sm->segments_rwlock);
  
    pool_get_zero (sm->segments, fs);
  
    /*
     * Allocate ssvm segment
     */
    segment_size = segment_size ? segment_size : props->add_segment_size;
    page_size = clib_mem_get_page_size ();
    /* Protect against segment size u32 wrap */
    segment_size = clib_max (segment_size + page_size - 1, segment_size);
    segment_size = segment_size & ~(page_size - 1);
  
    if (props->segment_type != SSVM_SEGMENT_PRIVATE)
      {
        seg_name = format (0, "%d-%d%c", getpid (), smm->seg_name_counter++, 0);
        alloc_size = (uword) segment_size + rnd_margin;
        baseva = clib_valloc_alloc (&smm->va_allocator, alloc_size, 0);
        if (!baseva)
  	{
  	  clib_warning ("out of space for segments");
  	  pool_put (sm->segments, fs);
  	  goto done;
  	}
      }
    else
      seg_name = format (0, "%s%c", "process-private", 0);
  
    fs->ssvm.ssvm_size = segment_size;
    fs->ssvm.name = seg_name;
    fs->ssvm.requested_va = baseva;
  
    if ((rv = ssvm_master_init (&fs->ssvm, props->segment_type)))
      {
        clib_warning ("svm_master_init ('%v', %u) failed", seg_name,
  		    segment_size);
  
        if (props->segment_type != SSVM_SEGMENT_PRIVATE)
  	clib_valloc_free (&smm->va_allocator, baseva);
        pool_put (sm->segments, fs);
        goto done;
      }
  
    /*
     * Initialize fifo segment
     */
    fs->n_slices = props->n_slices;
    fifo_segment_init (fs);
  
    /*
     * Save segment index before dropping lock, if any held
     */
    fs_index = fs - sm->segments;
  
  done:
  
    if (vlib_num_workers ())
      clib_rwlock_writer_unlock (&sm->segments_rwlock);
  
    return fs_index;
  }
  
  /**
   * Remove segment without lock
   */
  void
  segment_manager_del_segment (segment_manager_t * sm, fifo_segment_t * fs)
  {
    segment_manager_main_t *smm = &sm_main;
  
    if (ssvm_type (&fs->ssvm) != SSVM_SEGMENT_PRIVATE)
      {
        clib_valloc_free (&smm->va_allocator, fs->ssvm.requested_va);
  
        if (sm->app_wrk_index != SEGMENT_MANAGER_INVALID_APP_INDEX)
  	{
  	  app_worker_t *app_wrk;
  	  u64 segment_handle;
  	  app_wrk = app_worker_get (sm->app_wrk_index);
  	  segment_handle = segment_manager_segment_handle (sm, fs);
  	  app_worker_del_segment_notify (app_wrk, segment_handle);
  	}
      }
  
    ssvm_delete (&fs->ssvm);
  
    if (CLIB_DEBUG)
      clib_memset (fs, 0xfb, sizeof (*fs));
    pool_put (sm->segments, fs);
  }
  
  /**
   * Removes segment after acquiring writer lock
   */
  static inline void
  segment_manager_lock_and_del_segment (segment_manager_t * sm, u32 fs_index)
  {
    fifo_segment_t *fs;
    u8 is_prealloc;
  
    clib_rwlock_writer_lock (&sm->segments_rwlock);
    fs = segment_manager_get_segment (sm, fs_index);
    is_prealloc = fifo_segment_flags (fs) & FIFO_SEGMENT_F_IS_PREALLOCATED;
    if (is_prealloc && !segment_manager_app_detached (sm))
      {
        clib_rwlock_writer_unlock (&sm->segments_rwlock);
        return;
      }
  
    segment_manager_del_segment (sm, fs);
    clib_rwlock_writer_unlock (&sm->segments_rwlock);
  }
  
  /**
   * Reads a segment from the segment manager's pool without lock
   */
  fifo_segment_t *
  segment_manager_get_segment (segment_manager_t * sm, u32 segment_index)
  {
    return pool_elt_at_index (sm->segments, segment_index);
  }
  
  u64
  segment_manager_segment_handle (segment_manager_t * sm,
  				fifo_segment_t * segment)
  {
    u32 segment_index = segment_manager_segment_index (sm, segment);
    return (((u64) segment_manager_index (sm) << 32) | segment_index);
  }
  
  static void
  segment_manager_parse_segment_handle (u64 segment_handle, u32 * sm_index,
  				      u32 * segment_index)
  {
    *sm_index = segment_handle >> 32;
    *segment_index = segment_handle & 0xFFFFFFFF;
  }
  
  u64
  segment_manager_make_segment_handle (u32 segment_manager_index,
  				     u32 segment_index)
  {
    return (((u64) segment_manager_index << 32) | segment_index);
  }
  
  fifo_segment_t *
  segment_manager_get_segment_w_handle (u64 segment_handle)
  {
    u32 sm_index, segment_index;
    segment_manager_t *sm;
  
    segment_manager_parse_segment_handle (segment_handle, &sm_index,
  					&segment_index);
    sm = segment_manager_get (sm_index);
    if (!sm || pool_is_free_index (sm->segments, segment_index))
      return 0;
    return pool_elt_at_index (sm->segments, segment_index);
  }
  
  /**
   * Reads a segment from the segment manager's pool and acquires reader lock
   *
   * Caller must drop the reader's lock by calling
   * @ref segment_manager_segment_reader_unlock once it finishes working with
   * the segment.
   */
  fifo_segment_t *
  segment_manager_get_segment_w_lock (segment_manager_t * sm, u32 segment_index)
  {
    clib_rwlock_reader_lock (&sm->segments_rwlock);
    return pool_elt_at_index (sm->segments, segment_index);
  }
  
  void
  segment_manager_segment_reader_unlock (segment_manager_t * sm)
  {
    clib_rwlock_reader_unlock (&sm->segments_rwlock);
  }
  
  void
  segment_manager_segment_writer_unlock (segment_manager_t * sm)
  {
    clib_rwlock_writer_unlock (&sm->segments_rwlock);
  }
  
  segment_manager_t *
  segment_manager_alloc (void)
  {
    segment_manager_main_t *smm = &sm_main;
    segment_manager_t *sm;
  
    pool_get_zero (smm->segment_managers, sm);
    clib_rwlock_init (&sm->segments_rwlock);
    return sm;
  }
  
  /**
   * Initializes segment manager based on options provided.
   * Returns error if ssvm segment(s) allocation fails.
   */
  int
  segment_manager_init (segment_manager_t * sm, uword first_seg_size,
  		      u32 prealloc_fifo_pairs)
  {
    u32 rx_fifo_size, tx_fifo_size, pair_size;
    u32 rx_rounded_data_size, tx_rounded_data_size;
    u64 approx_total_size, max_seg_size = ((u64) 1 << 32) - (128 << 10);
    segment_manager_props_t *props;
    fifo_segment_t *segment;
    u32 approx_segment_count;
    int seg_index, i;
  
    props = segment_manager_properties_get (sm);
    first_seg_size = clib_max (first_seg_size, sm_main.default_segment_size);
  
    if (prealloc_fifo_pairs)
      {
        /* Figure out how many segments should be preallocated */
        rx_rounded_data_size = (1 << (max_log2 (props->rx_fifo_size)));
        tx_rounded_data_size = (1 << (max_log2 (props->tx_fifo_size)));
  
        rx_fifo_size = sizeof (svm_fifo_t) + rx_rounded_data_size;
        tx_fifo_size = sizeof (svm_fifo_t) + tx_rounded_data_size;
        pair_size = rx_fifo_size + tx_fifo_size;
  
        approx_total_size = (u64) prealloc_fifo_pairs *pair_size;
        if (first_seg_size > approx_total_size)
  	max_seg_size = first_seg_size;
        approx_segment_count = (approx_total_size + (max_seg_size - 1))
  	/ max_seg_size;
  
        /* Allocate the segments */
        for (i = 0; i < approx_segment_count + 1; i++)
  	{
  	  seg_index = segment_manager_add_segment (sm, max_seg_size);
  	  if (seg_index < 0)
  	    {
  	      clib_warning ("Failed to preallocate segment %d", i);
  	      return seg_index;
  	    }
  
  	  segment = segment_manager_get_segment (sm, seg_index);
  	  if (i == 0)
  	    sm->event_queue = segment_manager_alloc_queue (segment, props);
  
  	  fifo_segment_preallocate_fifo_pairs (segment,
  					       props->rx_fifo_size,
  					       props->tx_fifo_size,
  					       &prealloc_fifo_pairs);
  	  fifo_segment_flags (segment) = FIFO_SEGMENT_F_IS_PREALLOCATED;
  	  if (prealloc_fifo_pairs == 0)
  	    break;
  	}
      }
    else
      {
        seg_index = segment_manager_add_segment (sm, first_seg_size);
        if (seg_index < 0)
  	{
  	  clib_warning ("Failed to allocate segment");
  	  return seg_index;
  	}
        segment = segment_manager_get_segment (sm, seg_index);
        sm->event_queue = segment_manager_alloc_queue (segment, props);
      }
  
    return 0;
  }
  
  /**
   * Cleanup segment manager.
   */
  void
  segment_manager_free (segment_manager_t * sm)
  {
    segment_manager_main_t *smm = &sm_main;
    fifo_segment_t *fifo_segment;
  
    ASSERT (!segment_manager_has_fifos (sm)
  	  && segment_manager_app_detached (sm));
  
    /* If we have empty preallocated segments that haven't been removed, remove
     * them now. Apart from that, the first segment in the first segment manager
     * is not removed when all fifos are removed. It can only be removed when
     * the manager is explicitly deleted/detached by the app. */
    clib_rwlock_writer_lock (&sm->segments_rwlock);
  
    /* *INDENT-OFF* */
    pool_foreach (fifo_segment, sm->segments, ({
      segment_manager_del_segment (sm, fifo_segment);
    }));
    /* *INDENT-ON* */
  
    clib_rwlock_writer_unlock (&sm->segments_rwlock);
  
    clib_rwlock_free (&sm->segments_rwlock);
    if (CLIB_DEBUG)
      clib_memset (sm, 0xfe, sizeof (*sm));
    pool_put (smm->segment_managers, sm);
  }
  
  void
  segment_manager_init_free (segment_manager_t * sm)
  {
    segment_manager_app_detach (sm);
    if (segment_manager_has_fifos (sm))
      segment_manager_del_sessions (sm);
    else
      {
        ASSERT (!sm->first_is_protected || segment_manager_app_detached (sm));
        segment_manager_free (sm);
      }
  }
  
  segment_manager_t *
  segment_manager_get (u32 index)
  {
    return pool_elt_at_index (sm_main.segment_managers, index);
  }
  
  segment_manager_t *
  segment_manager_get_if_valid (u32 index)
  {
    if (pool_is_free_index (sm_main.segment_managers, index))
      return 0;
    return pool_elt_at_index (sm_main.segment_managers, index);
  }
  
  u32
  segment_manager_index (segment_manager_t * sm)
  {
    return sm - sm_main.segment_managers;
  }
  
  u8
  segment_manager_has_fifos (segment_manager_t * sm)
  {
    fifo_segment_t *seg;
    u8 first = 1;
  
    /* *INDENT-OFF* */
    segment_manager_foreach_segment_w_lock (seg, sm, ({
      if (CLIB_DEBUG && !first && !fifo_segment_has_fifos (seg)
  	&& !(fifo_segment_flags (seg) & FIFO_SEGMENT_F_IS_PREALLOCATED))
        {
  	clib_warning ("segment %d has no fifos!",
  	              segment_manager_segment_index (sm, seg));
  	first = 0;
        }
      if (fifo_segment_has_fifos (seg))
        {
  	segment_manager_segment_reader_unlock (sm);
  	return 1;
        }
    }));
    /* *INDENT-ON* */
  
    return 0;
  }
  
  /**
   * Initiate disconnects for all sessions 'owned' by a segment manager
   */
  void
  segment_manager_del_sessions (segment_manager_t * sm)
  {
    session_handle_t *handles = 0, *handle;
    fifo_segment_t *fs;
    session_t *session;
    int slice_index;
    svm_fifo_t *f;
  
    ASSERT (pool_elts (sm->segments) != 0);
  
    /* Across all fifo segments used by the server */
    /* *INDENT-OFF* */
    segment_manager_foreach_segment_w_lock (fs, sm, ({
      for (slice_index = 0; slice_index < fs->n_slices; slice_index++)
        {
          f = fifo_segment_get_slice_fifo_list (fs, slice_index);
  
          /*
           * Remove any residual sessions from the session lookup table
           * Don't bother deleting the individual fifos, we're going to
           * throw away the fifo segment in a minute.
           */
          while (f)
            {
              session = session_get_if_valid (f->master_session_index,
                                              f->master_thread_index);
              if (session)
                vec_add1 (handles, session_handle (session));
              f = f->next;
            }
        }
  
      /* Instead of removing the segment, test when cleaning up disconnected
       * sessions if the segment can be removed.
       */
    }));
    /* *INDENT-ON* */
  
    vec_foreach (handle, handles)
      session_close (session_get_from_handle (*handle));
  }
  
  int
  segment_manager_try_alloc_fifos (fifo_segment_t * fifo_segment,
  				 u32 thread_index,
  				 u32 rx_fifo_size, u32 tx_fifo_size,
  				 svm_fifo_t ** rx_fifo, svm_fifo_t ** tx_fifo)
  {
    rx_fifo_size = clib_max (rx_fifo_size, sm_main.default_fifo_size);
    *rx_fifo = fifo_segment_alloc_fifo_w_slice (fifo_segment, thread_index,
  					      rx_fifo_size,
  					      FIFO_SEGMENT_RX_FIFO);
  
    tx_fifo_size = clib_max (tx_fifo_size, sm_main.default_fifo_size);
    *tx_fifo = fifo_segment_alloc_fifo_w_slice (fifo_segment, thread_index,
  					      tx_fifo_size,
  					      FIFO_SEGMENT_TX_FIFO);
  
    if (*rx_fifo == 0)
      {
        /* This would be very odd, but handle it... */
        if (*tx_fifo != 0)
  	{
  	  fifo_segment_free_fifo (fifo_segment, *tx_fifo);
  	  *tx_fifo = 0;
  	}
        return -1;
      }
    if (*tx_fifo == 0)
      {
        if (*rx_fifo != 0)
  	{
  	  fifo_segment_free_fifo (fifo_segment, *rx_fifo);
  	  *rx_fifo = 0;
  	}
        return -1;
      }
  
    return 0;
  }
  
  int
  segment_manager_alloc_session_fifos (segment_manager_t * sm,
  				     u32 thread_index,
  				     svm_fifo_t ** rx_fifo,
  				     svm_fifo_t ** tx_fifo)
  {
    int alloc_fail = 1, rv = 0, new_fs_index;
    segment_manager_props_t *props;
    fifo_segment_t *fs = 0;
    u32 sm_index, fs_index;
    u8 added_a_segment = 0;
    u64 fs_handle;
  
    props = segment_manager_properties_get (sm);
  
    /*
     * Find the first free segment to allocate the fifos in
     */
  
    /* *INDENT-OFF* */
    segment_manager_foreach_segment_w_lock (fs, sm, ({
      alloc_fail = segment_manager_try_alloc_fifos (fs,
                                                    thread_index,
                                                    props->rx_fifo_size,
                                                    props->tx_fifo_size,
                                                    rx_fifo, tx_fifo);
      /* Exit with lock held, drop it after notifying app */
      if (!alloc_fail)
        goto alloc_success;
    }));
    /* *INDENT-ON* */
  
  alloc_check:
  
    if (!alloc_fail)
      {
  
      alloc_success:
  
        ASSERT (rx_fifo && tx_fifo);
        sm_index = segment_manager_index (sm);
        fs_index = segment_manager_segment_index (sm, fs);
        (*tx_fifo)->segment_manager = sm_index;
        (*rx_fifo)->segment_manager = sm_index;
        (*tx_fifo)->segment_index = fs_index;
        (*rx_fifo)->segment_index = fs_index;
  
        if (added_a_segment)
  	{
  	  app_worker_t *app_wrk;
  	  fs_handle = segment_manager_segment_handle (sm, fs);
  	  app_wrk = app_worker_get (sm->app_wrk_index);
  	  rv = app_worker_add_segment_notify (app_wrk, fs_handle);
  	}
        /* Drop the lock after app is notified */
        segment_manager_segment_reader_unlock (sm);
        return rv;
      }
  
    /*
     * Allocation failed, see if we can add a new segment
     */
    if (props->add_segment)
      {
        if (added_a_segment)
  	{
  	  clib_warning ("Added a segment, still can't allocate a fifo");
  	  segment_manager_segment_reader_unlock (sm);
  	  return SESSION_ERROR_NEW_SEG_NO_SPACE;
  	}
        if ((new_fs_index = segment_manager_add_segment (sm, 0)) < 0)
  	{
  	  clib_warning ("Failed to add new segment");
  	  return SESSION_ERROR_SEG_CREATE;
  	}
        fs = segment_manager_get_segment_w_lock (sm, new_fs_index);
        alloc_fail = segment_manager_try_alloc_fifos (fs, thread_index,
  						    props->rx_fifo_size,
  						    props->tx_fifo_size,
  						    rx_fifo, tx_fifo);
        added_a_segment = 1;
        goto alloc_check;
      }
    else
      {
        clib_warning ("Can't add new seg and no space to allocate fifos!");
        return SESSION_ERROR_NO_SPACE;
      }
  }
  
  void
  segment_manager_dealloc_fifos (svm_fifo_t * rx_fifo, svm_fifo_t * tx_fifo)
  {
    segment_manager_t *sm;
    fifo_segment_t *fs;
    u32 segment_index;
  
    if (!rx_fifo || !tx_fifo)
      return;
  
    /* It's possible to have no segment manager if the session was removed
     * as result of a detach. */
    if (!(sm = segment_manager_get_if_valid (rx_fifo->segment_manager)))
      return;
  
    segment_index = rx_fifo->segment_index;
    fs = segment_manager_get_segment_w_lock (sm, segment_index);
    fifo_segment_free_fifo (fs, rx_fifo);
    fifo_segment_free_fifo (fs, tx_fifo);
  
    /*
     * Try to remove svm segment if it has no fifos. This can be done only if
     * the segment is not the first in the segment manager or if it is first
     * and it is not protected. Moreover, if the segment is first and the app
     * has detached from the segment manager, remove the segment manager.
     */
    if (!fifo_segment_has_fifos (fs))
      {
        segment_manager_segment_reader_unlock (sm);
  
        /* Remove segment if it holds no fifos or first but not protected */
        if (segment_index != 0 || !sm->first_is_protected)
  	segment_manager_lock_and_del_segment (sm, segment_index);
  
        /* Remove segment manager if no sessions and detached from app */
        if (segment_manager_app_detached (sm)
  	  && !segment_manager_has_fifos (sm))
  	{
  	  segment_manager_free (sm);
  	}
      }
    else
      segment_manager_segment_reader_unlock (sm);
  }
  
  int
  segment_manager_grow_fifo (segment_manager_t * sm, svm_fifo_t * f, u32 size)
  {
    fifo_segment_t *fs;
    int rv;
  
    fs = segment_manager_get_segment_w_lock (sm, f->segment_index);
    rv = fifo_segment_grow_fifo (fs, f, size);
    segment_manager_segment_reader_unlock (sm);
  
    return rv;
  }
  
  int
  segment_manager_collect_fifo_chunks (segment_manager_t * sm, svm_fifo_t * f)
  {
    fifo_segment_t *fs;
    int rv;
  
    fs = segment_manager_get_segment_w_lock (sm, f->segment_index);
    rv = fifo_segment_collect_fifo_chunks (fs, f);
    segment_manager_segment_reader_unlock (sm);
  
    return rv;
  }
  
  int
  segment_manager_shrink_fifo (segment_manager_t * sm, svm_fifo_t * f, u32 size,
  			     u8 is_producer)
  {
    int rv;
  
    rv = svm_fifo_reduce_size (f, size, is_producer);
  
    /* Nothing to collect at this point */
    if (!is_producer)
      return rv;
  
    if (f->flags & SVM_FIFO_F_COLLECT_CHUNKS)
      segment_manager_collect_fifo_chunks (sm, f);
  
    return rv;
  }
  
  u32
  segment_manager_evt_q_expected_size (u32 q_len)
  {
    u32 fifo_evt_size, notif_q_size, q_hdrs;
    u32 msg_q_sz, fifo_evt_ring_sz, session_ntf_ring_sz;
  
    fifo_evt_size = 1 << max_log2 (sizeof (session_event_t));
    notif_q_size = clib_max (16, q_len >> 4);
  
    msg_q_sz = q_len * sizeof (svm_msg_q_msg_t);
    fifo_evt_ring_sz = q_len * fifo_evt_size;
    session_ntf_ring_sz = notif_q_size * 256;
    q_hdrs = sizeof (svm_queue_t) + sizeof (svm_msg_q_t);
  
    return (msg_q_sz + fifo_evt_ring_sz + session_ntf_ring_sz + q_hdrs);
  }
  
  /**
   * Allocates shm queue in the first segment
   *
   * Must be called with lock held
   */
  svm_msg_q_t *
  segment_manager_alloc_queue (fifo_segment_t * segment,
  			     segment_manager_props_t * props)
  {
    u32 fifo_evt_size, session_evt_size = 256, notif_q_size;
    svm_msg_q_cfg_t _cfg, *cfg = &_cfg;
    svm_msg_q_t *q;
    void *oldheap;
  
    fifo_evt_size = sizeof (session_event_t);
    notif_q_size = clib_max (16, props->evt_q_size >> 4);
    /* *INDENT-OFF* */
    svm_msg_q_ring_cfg_t rc[SESSION_MQ_N_RINGS] = {
      {props->evt_q_size, fifo_evt_size, 0},
      {notif_q_size, session_evt_size, 0}
    };
    /* *INDENT-ON* */
    cfg->consumer_pid = 0;
    cfg->n_rings = 2;
    cfg->q_nitems = props->evt_q_size;
    cfg->ring_cfgs = rc;
  
    oldheap = ssvm_push_heap (segment->ssvm.sh);
    q = svm_msg_q_alloc (cfg);
    fifo_segment_update_free_bytes (segment);
    ssvm_pop_heap (oldheap);
  
    if (props->use_mq_eventfd)
      {
        if (svm_msg_q_alloc_producer_eventfd (q))
  	clib_warning ("failed to alloc eventfd");
      }
    return q;
  }
  
  svm_msg_q_t *
  segment_manager_event_queue (segment_manager_t * sm)
  {
    return sm->event_queue;
  }
  
  /**
   * Frees shm queue allocated in the first segment
   */
  void
  segment_manager_dealloc_queue (segment_manager_t * sm, svm_queue_t * q)
  {
    fifo_segment_t *segment;
    ssvm_shared_header_t *sh;
    void *oldheap;
  
    ASSERT (!pool_is_free_index (sm->segments, 0));
  
    segment = segment_manager_get_segment_w_lock (sm, 0);
    sh = segment->ssvm.sh;
  
    oldheap = ssvm_push_heap (sh);
    svm_queue_free (q);
    ssvm_pop_heap (oldheap);
    segment_manager_segment_reader_unlock (sm);
  }
  
  /*
   * Init segment vm address allocator
   */
  void
  segment_manager_main_init (segment_manager_main_init_args_t * a)
  {
    segment_manager_main_t *sm = &sm_main;
    clib_valloc_chunk_t _ip, *ip = &_ip;
  
    ip->baseva = a->baseva;
    ip->size = a->size;
  
    clib_valloc_init (&sm->va_allocator, ip, 1 /* lock */ );
  
    sm->default_fifo_size = 1 << 12;
    sm->default_segment_size = 1 << 20;
    sm->default_app_mq_size = 128;
  }
  
  static clib_error_t *
  segment_manager_show_fn (vlib_main_t * vm, unformat_input_t * input,
  			 vlib_cli_command_t * cmd)
  {
    segment_manager_main_t *smm = &sm_main;
    u8 show_segments = 0, verbose = 0;
    segment_manager_t *sm;
    fifo_segment_t *seg;
  
    while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
      {
        if (unformat (input, "segments"))
  	show_segments = 1;
        else if (unformat (input, "verbose"))
  	verbose = 1;
        else
  	return clib_error_return (0, "unknown input `%U'",
  				  format_unformat_error, input);
      }
    vlib_cli_output (vm, "%d segment managers allocated",
  		   pool_elts (smm->segment_managers));
    if (verbose && pool_elts (smm->segment_managers))
      {
        vlib_cli_output (vm, "%-10s%=15s%=12s", "Index", "App Index",
  		       "Segments");
  
        /* *INDENT-OFF* */
        pool_foreach (sm, smm->segment_managers, ({
  	vlib_cli_output (vm, "%-10d%=15d%=12d", segment_manager_index (sm),
  			   sm->app_wrk_index, pool_elts (sm->segments));
        }));
        /* *INDENT-ON* */
  
      }
    if (show_segments)
      {
        vlib_cli_output (vm, "%U", format_fifo_segment, 0, verbose);
  
        /* *INDENT-OFF* */
        pool_foreach (sm, smm->segment_managers, ({
  	  segment_manager_foreach_segment_w_lock (seg, sm, ({
  	    vlib_cli_output (vm, "%U", format_fifo_segment, seg, verbose);
  	  }));
        }));
        /* *INDENT-ON* */
  
      }
    return 0;
  }
  
  /* *INDENT-OFF* */
  VLIB_CLI_COMMAND (segment_manager_show_command, static) =
  {
    .path = "show segment-manager",
    .short_help = "show segment-manager [segments][verbose]",
    .function = segment_manager_show_fn,
  };
  /* *INDENT-ON* */
  
  void
  segment_manager_format_sessions (segment_manager_t * sm, int verbose)
  {
    vlib_main_t *vm = vlib_get_main ();
    app_worker_t *app_wrk;
    fifo_segment_t *fs;
    const u8 *app_name;
    int slice_index;
    u8 *s = 0, *str;
    svm_fifo_t *f;
  
    if (!sm)
      {
        if (verbose)
  	vlib_cli_output (vm, "%-40s%-20s%-15s%-10s", "Connection", "App",
  			 "API Client", "SegManager");
        else
  	vlib_cli_output (vm, "%-40s%-20s", "Connection", "App");
        return;
      }
  
    app_wrk = app_worker_get (sm->app_wrk_index);
    app_name = application_name_from_index (app_wrk->app_index);
  
    clib_rwlock_reader_lock (&sm->segments_rwlock);
  
    /* *INDENT-OFF* */
    pool_foreach (fs, sm->segments, ({
      for (slice_index = 0; slice_index < fs->n_slices; slice_index++)
        {
          f = fifo_segment_get_slice_fifo_list (fs, slice_index);
          while (f)
            {
              u32 session_index, thread_index;
              session_t *session;
  
              session_index = f->master_session_index;
              thread_index = f->master_thread_index;
  
              session = session_get (session_index, thread_index);
              str = format (0, "%U", format_session, session, verbose);
  
              if (verbose)
                s = format (s, "%-40s%-20s%-15u%-10u", str, app_name,
                            app_wrk->api_client_index, app_wrk->connects_seg_manager);
              else
                s = format (s, "%-40s%-20s", str, app_name);
  
              vlib_cli_output (vm, "%v", s);
              vec_reset_length (s);
              vec_free (str);
  
              f = f->next;
            }
          vec_free (s);
        }
    }));
    /* *INDENT-ON* */
  
    clib_rwlock_reader_unlock (&sm->segments_rwlock);
  }
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  