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path: root/docs/configuration/config_getting_started.rst

Age	Commit message (Collapse)	Author	Files	Lines
2021-10-13	docs: better docs, mv doxygen to sphinx	Nathan Skrzypczak	1	-0/+84
	This patch refactors the VPP sphinx docs in order to make it easier to consume for external readers as well as VPP developers. It also makes sphinx the single source of documentation, which simplifies maintenance and operation. Most important updates are: - reformat the existing documentation as rst - split RELEASE.md and move it into separate rst files - remove section 'events' - remove section 'archive' - remove section 'related projects' - remove section 'feature by release' - remove section 'Various links' - make (Configuration reference, CLI docs, developer docs) top level items in the list - move 'Use Cases' as part of 'About VPP' - move 'Troubleshooting' as part of 'Getting Started' - move test framework docs into 'Developer Documentation' - add a 'Contributing' section for gerrit, docs and other contributer related infos - deprecate doxygen and test-docs targets - redirect the "make doxygen" target to "make docs" Type: refactor Change-Id: I552a5645d5b7964d547f99b1336e2ac24e7c209f Signed-off-by: Nathan Skrzypczak <nathan.skrzypczak@gmail.com> Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>

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/*
 * 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;
  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, u32 segment_size)
{
  segment_manager_main_t *smm = &sm_main;
  u32 rnd_margin = 128 << 10, fs_index = ~0, page_size;
  uword baseva = (uword) ~ 0ULL, alloc_size;
  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
   */
  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, u32 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)
{
  fifo_segment_t *fifo_segment;
  session_handle_t *handles = 0, *handle;
  session_t *session;
  svm_fifo_t *fifo;

  ASSERT (pool_elts (sm->segments) != 0);

  /* Across all fifo segments used by the server */
  /* *INDENT-OFF* */
  segment_manager_foreach_segment_w_lock (fifo_segment, sm, ({
    fifo = fifo_segment_get_fifo_list (fifo_segment);

    /*
     * 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 (fifo)
      {
	session = session_get_if_valid (fifo->master_session_index,
	                                fifo->master_thread_index);
	if (session)
	  vec_add1 (handles, session_handle (session));
	fifo = fifo->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 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 (fifo_segment, 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 (fifo_segment, 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,
				     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,
                                                  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, 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)
{
  fifo_segment_t *fifo_segment;
  vlib_main_t *vm = vlib_get_main ();
  app_worker_t *app_wrk;
  const u8 *app_name;
  u8 *s = 0;

  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 (fifo_segment, sm->segments, ({
    svm_fifo_t *fifo;
    u8 *str;

    fifo = fifo_segment_get_fifo_list (fifo_segment);
    while (fifo)
      {
        u32 session_index, thread_index;
        session_t *session;

        session_index = fifo->master_session_index;
        thread_index = fifo->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);

        fifo = fifo->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:
 */