text: /*
   * Copyright (c) 2015 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.
   */
  
  /** @cond DOCUMENTATION_IS_IN_BIHASH_DOC_H */
  
  static inline void *BV (alloc_aligned) (BVT (clib_bihash) * h, uword nbytes)
  {
    uword rv;
  
    /* Round to an even number of cache lines */
    nbytes += CLIB_CACHE_LINE_BYTES - 1;
    nbytes &= ~(CLIB_CACHE_LINE_BYTES - 1);
  
    rv = alloc_arena_next (h);
    alloc_arena_next (h) += nbytes;
  
    if (rv >= alloc_arena_size (h))
      os_out_of_memory ();
  
    return (void *) (uword) (rv + alloc_arena (h));
  }
  
  void BV (clib_bihash_instantiate) (BVT (clib_bihash) * h)
  {
    uword bucket_size;
  
    alloc_arena (h) = (uword) clib_mem_vm_alloc (h->memory_size);
    alloc_arena_next (h) = 0;
    alloc_arena_size (h) = h->memory_size;
  
    bucket_size = h->nbuckets * sizeof (h->buckets[0]);
    h->buckets = BV (alloc_aligned) (h, bucket_size);
  
    h->alloc_lock = BV (alloc_aligned) (h, CLIB_CACHE_LINE_BYTES);
    h->alloc_lock[0] = 0;
  }
  
  void BV (clib_bihash_init)
    (BVT (clib_bihash) * h, char *name, u32 nbuckets, uword memory_size)
  {
    int i;
    void *oldheap;
    nbuckets = 1 << (max_log2 (nbuckets));
  
    h->name = (u8 *) name;
    h->nbuckets = nbuckets;
    h->log2_nbuckets = max_log2 (nbuckets);
    h->memory_size = memory_size;
    alloc_arena (h) = 0;
  
    /*
     * Make sure the requested size is rational. The max table
     * size without playing the alignment card is 64 Gbytes.
     * If someone starts complaining that's not enough, we can shift
     * the offset by CLIB_LOG2_CACHE_LINE_BYTES...
     */
    ASSERT (memory_size < (1ULL << BIHASH_BUCKET_OFFSET_BITS));
    h->fmt_fn = NULL;
  
    /* Add this hash table to the list */
    for (i = 0; i < vec_len (clib_all_bihashes); i++)
      if (clib_all_bihashes[i] == h)
        return;
  
    /* Unfortunately, the heap push/pop is required.... */
    oldheap = clib_all_bihash_set_heap ();
    vec_add1 (clib_all_bihashes, (void *) h);
    clib_mem_set_heap (oldheap);
  
  #if BIHASH_INSTANTIATE_IMMEDIATELY
    BV (clib_bihash_instantiate) (h);
  #endif
  }
  
  #if BIHASH_32_64_SVM
  #if !defined (MFD_ALLOW_SEALING)
  #define MFD_ALLOW_SEALING 0x0002U
  #endif
  
  void BV (clib_bihash_master_init_svm)
    (BVT (clib_bihash) * h, char *name, u32 nbuckets, u64 memory_size)
  {
    uword bucket_size;
    u8 *mmap_addr;
    vec_header_t *freelist_vh;
    int fd;
  
    ASSERT (memory_size < (1ULL << 32));
    /* Set up for memfd sharing */
    if ((fd = memfd_create (name, MFD_ALLOW_SEALING)) == -1)
      {
        clib_unix_warning ("memfd_create");
        return;
      }
  
    if (ftruncate (fd, memory_size) < 0)
      {
        clib_unix_warning ("ftruncate");
        return;
      }
  
    /* Not mission-critical, complain and continue */
    if ((fcntl (fd, F_ADD_SEALS, F_SEAL_SHRINK)) == -1)
      clib_unix_warning ("fcntl (F_ADD_SEALS)");
  
    mmap_addr = mmap (0, memory_size,
  		    PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0 /* offset */ );
  
    if (mmap_addr == MAP_FAILED)
      {
        clib_unix_warning ("mmap failed");
        ASSERT (0);
      }
  
    h->sh = (void *) mmap_addr;
    h->memfd = fd;
    nbuckets = 1 << (max_log2 (nbuckets));
  
    h->name = (u8 *) name;
    h->sh->nbuckets = h->nbuckets = nbuckets;
    h->log2_nbuckets = max_log2 (nbuckets);
  
    alloc_arena (h) = (u64) (uword) mmap_addr;
    alloc_arena_next (h) = CLIB_CACHE_LINE_BYTES;
    alloc_arena_size (h) = memory_size;
  
    bucket_size = nbuckets * sizeof (h->buckets[0]);
    h->buckets = BV (alloc_aligned) (h, bucket_size);
    h->sh->buckets_as_u64 = (u64) BV (clib_bihash_get_offset) (h, h->buckets);
  
    h->alloc_lock = BV (alloc_aligned) (h, CLIB_CACHE_LINE_BYTES);
    h->alloc_lock[0] = 0;
  
    h->sh->alloc_lock_as_u64 =
      (u64) BV (clib_bihash_get_offset) (h, (void *) h->alloc_lock);
    freelist_vh =
      BV (alloc_aligned) (h,
  			sizeof (vec_header_t) +
  			BIHASH_FREELIST_LENGTH * sizeof (u64));
    freelist_vh->len = BIHASH_FREELIST_LENGTH;
    freelist_vh->dlmalloc_header_offset = 0xDEADBEEF;
    h->sh->freelists_as_u64 =
      (u64) BV (clib_bihash_get_offset) (h, freelist_vh->vector_data);
    h->freelists = (void *) (freelist_vh->vector_data);
  
    h->fmt_fn = NULL;
  }
  
  void BV (clib_bihash_slave_init_svm)
    (BVT (clib_bihash) * h, char *name, int fd)
  {
    u8 *mmap_addr;
    u64 memory_size;
    BVT (clib_bihash_shared_header) * sh;
  
    /* Trial mapping, to learn the segment size */
    mmap_addr = mmap (0, 4096, PROT_READ, MAP_SHARED, fd, 0 /* offset */ );
    if (mmap_addr == MAP_FAILED)
      {
        clib_unix_warning ("trial mmap failed");
        ASSERT (0);
      }
  
    sh = (BVT (clib_bihash_shared_header) *) mmap_addr;
  
    memory_size = sh->alloc_arena_size;
  
    munmap (mmap_addr, 4096);
  
    /* Actual mapping, at the required size */
    mmap_addr = mmap (0, memory_size,
  		    PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0 /* offset */ );
  
    if (mmap_addr == MAP_FAILED)
      {
        clib_unix_warning ("mmap failed");
        ASSERT (0);
      }
  
    (void) close (fd);
  
    h->sh = (void *) mmap_addr;
    alloc_arena (h) = (u64) (uword) mmap_addr;
    h->memfd = -1;
  
    h->name = (u8 *) name;
    h->buckets = BV (clib_bihash_get_value) (h, h->sh->buckets_as_u64);
    h->nbuckets = h->sh->nbuckets;
    h->log2_nbuckets = max_log2 (h->nbuckets);
  
    h->alloc_lock = BV (clib_bihash_get_value) (h, h->sh->alloc_lock_as_u64);
    h->freelists = BV (clib_bihash_get_value) (h, h->sh->freelists_as_u64);
    h->fmt_fn = NULL;
  }
  #endif /* BIHASH_32_64_SVM */
  
  void BV (clib_bihash_set_kvp_format_fn) (BVT (clib_bihash) * h,
  					 format_function_t * fmt_fn)
  {
    h->fmt_fn = fmt_fn;
  }
  
  void BV (clib_bihash_free) (BVT (clib_bihash) * h)
  {
    int i;
  
    if (PREDICT_FALSE (alloc_arena (h) == 0))
      goto never_initialized;
  
    vec_free (h->working_copies);
    vec_free (h->working_copy_lengths);
  #if BIHASH_32_64_SVM == 0
    vec_free (h->freelists);
  #else
    if (h->memfd > 0)
      (void) close (h->memfd);
  #endif
    clib_mem_vm_free ((void *) (uword) (alloc_arena (h)), alloc_arena_size (h));
  never_initialized:
    clib_memset (h, 0, sizeof (*h));
    for (i = 0; i < vec_len (clib_all_bihashes); i++)
      {
        if ((void *) h == clib_all_bihashes[i])
  	{
  	  vec_delete (clib_all_bihashes, 1, i);
  	  return;
  	}
      }
    clib_warning ("Couldn't find hash table %llx on clib_all_bihashes...",
  		(u64) h);
  }
  
  static
  BVT (clib_bihash_value) *
  BV (value_alloc) (BVT (clib_bihash) * h, u32 log2_pages)
  {
    BVT (clib_bihash_value) * rv = 0;
  
    ASSERT (h->alloc_lock[0]);
  
  #if BIHASH_32_64_SVM
    ASSERT (log2_pages < vec_len (h->freelists));
  #endif
  
    if (log2_pages >= vec_len (h->freelists) || h->freelists[log2_pages] == 0)
      {
        vec_validate_init_empty (h->freelists, log2_pages, 0);
        rv = BV (alloc_aligned) (h, (sizeof (*rv) * (1 << log2_pages)));
        goto initialize;
      }
    rv = BV (clib_bihash_get_value) (h, (uword) h->freelists[log2_pages]);
    h->freelists[log2_pages] = rv->next_free_as_u64;
  
  initialize:
    ASSERT (rv);
    /*
     * Latest gcc complains that the length arg is zero
     * if we replace (1<<log2_pages) with vec_len(rv).
     * No clue.
     */
    clib_memset (rv, 0xff, sizeof (*rv) * (1 << log2_pages));
    return rv;
  }
  
  static void
  BV (value_free) (BVT (clib_bihash) * h, BVT (clib_bihash_value) * v,
  		 u32 log2_pages)
  {
    ASSERT (h->alloc_lock[0]);
  
    ASSERT (vec_len (h->freelists) > log2_pages);
  
    if (CLIB_DEBUG > 0)
      clib_memset (v, 0xFE, sizeof (*v) * (1 << log2_pages));
  
    v->next_free_as_u64 = (u64) h->freelists[log2_pages];
    h->freelists[log2_pages] = (u64) BV (clib_bihash_get_offset) (h, v);
  }
  
  static inline void
  BV (make_working_copy) (BVT (clib_bihash) * h, BVT (clib_bihash_bucket) * b)
  {
    BVT (clib_bihash_value) * v;
    BVT (clib_bihash_bucket) working_bucket __attribute__ ((aligned (8)));
    BVT (clib_bihash_value) * working_copy;
    u32 thread_index = os_get_thread_index ();
    int log2_working_copy_length;
  
    ASSERT (h->alloc_lock[0]);
  
    if (thread_index >= vec_len (h->working_copies))
      {
        vec_validate (h->working_copies, thread_index);
        vec_validate_init_empty (h->working_copy_lengths, thread_index, ~0);
      }
  
    /*
     * working_copies are per-cpu so that near-simultaneous
     * updates from multiple threads will not result in sporadic, spurious
     * lookup failures.
     */
    working_copy = h->working_copies[thread_index];
    log2_working_copy_length = h->working_copy_lengths[thread_index];
  
    h->saved_bucket.as_u64 = b->as_u64;
  
    if (b->log2_pages > log2_working_copy_length)
      {
        /*
         * It's not worth the bookkeeping to free working copies
         *   if (working_copy)
         *     clib_mem_free (working_copy);
         */
        working_copy = BV (alloc_aligned)
  	(h, sizeof (working_copy[0]) * (1 << b->log2_pages));
        h->working_copy_lengths[thread_index] = b->log2_pages;
        h->working_copies[thread_index] = working_copy;
  
        BV (clib_bihash_increment_stat) (h, BIHASH_STAT_working_copy_lost,
  				       1ULL << b->log2_pages);
      }
  
    v = BV (clib_bihash_get_value) (h, b->offset);
  
    clib_memcpy_fast (working_copy, v, sizeof (*v) * (1 << b->log2_pages));
    working_bucket.as_u64 = b->as_u64;
    working_bucket.offset = BV (clib_bihash_get_offset) (h, working_copy);
    CLIB_MEMORY_BARRIER ();
    b->as_u64 = working_bucket.as_u64;
    h->working_copies[thread_index] = working_copy;
  }
  
  static
  BVT (clib_bihash_value) *
  BV (split_and_rehash)
    (BVT (clib_bihash) * h,
     BVT (clib_bihash_value) * old_values, u32 old_log2_pages,
     u32 new_log2_pages)
  {
    BVT (clib_bihash_value) * new_values, *new_v;
    int i, j, length_in_kvs;
  
    ASSERT (h->alloc_lock[0]);
  
    new_values = BV (value_alloc) (h, new_log2_pages);
    length_in_kvs = (1 << old_log2_pages) * BIHASH_KVP_PER_PAGE;
  
    for (i = 0; i < length_in_kvs; i++)
      {
        u64 new_hash;
  
        /* Entry not in use? Forget it */
        if (BV (clib_bihash_is_free) (&(old_values->kvp[i])))
  	continue;
  
        /* rehash the item onto its new home-page */
        new_hash = BV (clib_bihash_hash) (&(old_values->kvp[i]));
        new_hash >>= h->log2_nbuckets;
        new_hash &= (1 << new_log2_pages) - 1;
        new_v = &new_values[new_hash];
  
        /* Across the new home-page */
        for (j = 0; j < BIHASH_KVP_PER_PAGE; j++)
  	{
  	  /* Empty slot */
  	  if (BV (clib_bihash_is_free) (&(new_v->kvp[j])))
  	    {
  	      clib_memcpy_fast (&(new_v->kvp[j]), &(old_values->kvp[i]),
  				sizeof (new_v->kvp[j]));
  	      goto doublebreak;
  	    }
  	}
        /* Crap. Tell caller to try again */
        BV (value_free) (h, new_values, new_log2_pages);
        return 0;
      doublebreak:;
      }
  
    return new_values;
  }
  
  static
  BVT (clib_bihash_value) *
  BV (split_and_rehash_linear)
    (BVT (clib_bihash) * h,
     BVT (clib_bihash_value) * old_values, u32 old_log2_pages,
     u32 new_log2_pages)
  {
    BVT (clib_bihash_value) * new_values;
    int i, j, new_length, old_length;
  
    ASSERT (h->alloc_lock[0]);
  
    new_values = BV (value_alloc) (h, new_log2_pages);
    new_length = (1 << new_log2_pages) * BIHASH_KVP_PER_PAGE;
    old_length = (1 << old_log2_pages) * BIHASH_KVP_PER_PAGE;
  
    j = 0;
    /* Across the old value array */
    for (i = 0; i < old_length; i++)
      {
        /* Find a free slot in the new linear scan bucket */
        for (; j < new_length; j++)
  	{
  	  /* Old value not in use? Forget it. */
  	  if (BV (clib_bihash_is_free) (&(old_values->kvp[i])))
  	    goto doublebreak;
  
  	  /* New value should never be in use */
  	  if (BV (clib_bihash_is_free) (&(new_values->kvp[j])))
  	    {
  	      /* Copy the old value and move along */
  	      clib_memcpy_fast (&(new_values->kvp[j]), &(old_values->kvp[i]),
  				sizeof (new_values->kvp[j]));
  	      j++;
  	      goto doublebreak;
  	    }
  	}
        /* This should never happen... */
        clib_warning ("BUG: linear rehash failed!");
        BV (value_free) (h, new_values, new_log2_pages);
        return 0;
  
      doublebreak:;
      }
    return new_values;
  }
  
  static inline int BV (clib_bihash_add_del_inline)
    (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add,
     int (*is_stale_cb) (BVT (clib_bihash_kv) *, void *), void *arg)
  {
    u32 bucket_index;
    BVT (clib_bihash_bucket) * b, tmp_b;
    BVT (clib_bihash_value) * v, *new_v, *save_new_v, *working_copy;
    int i, limit;
    u64 hash, new_hash;
    u32 new_log2_pages, old_log2_pages;
    u32 thread_index = os_get_thread_index ();
    int mark_bucket_linear;
    int resplit_once;
  
    /* Create the table (is_add=1), or flunk the request now (is_add=0) */
    if (PREDICT_FALSE (alloc_arena (h) == 0))
      {
        if (is_add == 0)
  	return (-1);
        BV (clib_bihash_instantiate) (h);
      }
  
    hash = BV (clib_bihash_hash) (add_v);
  
    bucket_index = hash & (h->nbuckets - 1);
    b = &h->buckets[bucket_index];
  
    hash >>= h->log2_nbuckets;
  
    BV (clib_bihash_lock_bucket) (b);
  
    /* First elt in the bucket? */
    if (BV (clib_bihash_bucket_is_empty) (b))
      {
        if (is_add == 0)
  	{
  	  BV (clib_bihash_unlock_bucket) (b);
  	  return (-1);
  	}
  
        BV (clib_bihash_alloc_lock) (h);
        v = BV (value_alloc) (h, 0);
        BV (clib_bihash_alloc_unlock) (h);
  
        *v->kvp = *add_v;
        tmp_b.as_u64 = 0;		/* clears bucket lock */
        tmp_b.offset = BV (clib_bihash_get_offset) (h, v);
        tmp_b.refcnt = 1;
        CLIB_MEMORY_BARRIER ();
  
        b->as_u64 = tmp_b.as_u64;	/* unlocks the bucket */
        BV (clib_bihash_increment_stat) (h, BIHASH_STAT_alloc_add, 1);
  
        return (0);
      }
  
    /* WARNING: we're still looking at the live copy... */
    limit = BIHASH_KVP_PER_PAGE;
    v = BV (clib_bihash_get_value) (h, b->offset);
  
    v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
    if (b->linear_search)
      limit <<= b->log2_pages;
  
    if (is_add)
      {
        /*
         * Because reader threads are looking at live data,
         * we have to be extra careful. Readers do NOT hold the
         * bucket lock. We need to be SLOWER than a search, past the
         * point where readers CHECK the bucket lock.
         */
  
        /*
         * For obvious (in hindsight) reasons, see if we're supposed to
         * replace an existing key, then look for an empty slot.
         */
        for (i = 0; i < limit; i++)
  	{
  	  if (BV (clib_bihash_key_compare) (v->kvp[i].key, add_v->key))
  	    {
  	      /* Add but do not overwrite? */
  	      if (is_add == 2)
  		{
  		  BV (clib_bihash_unlock_bucket) (b);
  		  return (-2);
  		}
  
  	      CLIB_MEMORY_BARRIER ();	/* Add a delay */
  	      clib_memcpy_fast (&(v->kvp[i]), add_v, sizeof (*add_v));
  	      BV (clib_bihash_unlock_bucket) (b);
  	      BV (clib_bihash_increment_stat) (h, BIHASH_STAT_replace, 1);
  	      return (0);
  	    }
  	}
        /*
         * Look for an empty slot. If found, use it
         */
        for (i = 0; i < limit; i++)
  	{
  	  if (BV (clib_bihash_is_free) (&(v->kvp[i])))
  	    {
  	      /*
  	       * Copy the value first, so that if a reader manages
  	       * to match the new key, the value will be right...
  	       */
  	      clib_memcpy_fast (&(v->kvp[i].value),
  				&add_v->value, sizeof (add_v->value));
  	      CLIB_MEMORY_BARRIER ();	/* Make sure the value has settled */
  	      clib_memcpy_fast (&(v->kvp[i]), &add_v->key,
  				sizeof (add_v->key));
  	      b->refcnt++;
  	      ASSERT (b->refcnt > 0);
  	      BV (clib_bihash_unlock_bucket) (b);
  	      BV (clib_bihash_increment_stat) (h, BIHASH_STAT_add, 1);
  	      return (0);
  	    }
  	}
        /* look for stale data to overwrite */
        if (is_stale_cb)
  	{
  	  for (i = 0; i < limit; i++)
  	    {
  	      if (is_stale_cb (&(v->kvp[i]), arg))
  		{
  		  CLIB_MEMORY_BARRIER ();
  		  clib_memcpy_fast (&(v->kvp[i]), add_v, sizeof (*add_v));
  		  BV (clib_bihash_unlock_bucket) (b);
  		  BV (clib_bihash_increment_stat) (h, BIHASH_STAT_replace, 1);
  		  return (0);
  		}
  	    }
  	}
        /* Out of space in this bucket, split the bucket... */
      }
    else				/* delete case */
      {
        for (i = 0; i < limit; i++)
  	{
  	  /* Found the key? Kill it... */
  	  if (BV (clib_bihash_key_compare) (v->kvp[i].key, add_v->key))
  	    {
  	      clib_memset (&(v->kvp[i]), 0xff, sizeof (*(add_v)));
  	      /* Is the bucket empty? */
  	      if (PREDICT_TRUE (b->refcnt > 1))
  		{
  		  b->refcnt--;
  		  BV (clib_bihash_unlock_bucket) (b);
  		  BV (clib_bihash_increment_stat) (h, BIHASH_STAT_del, 1);
  		  return (0);
  		}
  	      else		/* yes, free it */
  		{
  		  /* Save old bucket value, need log2_pages to free it */
  		  tmp_b.as_u64 = b->as_u64;
  		  CLIB_MEMORY_BARRIER ();
  
  		  /* Kill and unlock the bucket */
  		  b->as_u64 = 0;
  
  		  /* And free the backing storage */
  		  BV (clib_bihash_alloc_lock) (h);
  		  /* Note: v currently points into the middle of the bucket */
  		  v = BV (clib_bihash_get_value) (h, tmp_b.offset);
  		  BV (value_free) (h, v, tmp_b.log2_pages);
  		  BV (clib_bihash_alloc_unlock) (h);
  		  BV (clib_bihash_increment_stat) (h, BIHASH_STAT_del_free,
  						   1);
  		  return (0);
  		}
  	    }
  	}
        /* Not found... */
        BV (clib_bihash_unlock_bucket) (b);
        return (-3);
      }
  
    /* Move readers to a (locked) temp copy of the bucket */
    BV (clib_bihash_alloc_lock) (h);
    BV (make_working_copy) (h, b);
  
    v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
  
    old_log2_pages = h->saved_bucket.log2_pages;
    new_log2_pages = old_log2_pages + 1;
    mark_bucket_linear = 0;
    BV (clib_bihash_increment_stat) (h, BIHASH_STAT_split_add, 1);
    BV (clib_bihash_increment_stat) (h, BIHASH_STAT_splits, old_log2_pages);
  
    working_copy = h->working_copies[thread_index];
    resplit_once = 0;
    BV (clib_bihash_increment_stat) (h, BIHASH_STAT_splits, 1);
  
    new_v = BV (split_and_rehash) (h, working_copy, old_log2_pages,
  				 new_log2_pages);
    if (new_v == 0)
      {
      try_resplit:
        resplit_once = 1;
        new_log2_pages++;
        /* Try re-splitting. If that fails, fall back to linear search */
        new_v = BV (split_and_rehash) (h, working_copy, old_log2_pages,
  				     new_log2_pages);
        if (new_v == 0)
  	{
  	mark_linear:
  	  new_log2_pages--;
  	  /* pinned collisions, use linear search */
  	  new_v =
  	    BV (split_and_rehash_linear) (h, working_copy, old_log2_pages,
  					  new_log2_pages);
  	  mark_bucket_linear = 1;
  	  BV (clib_bihash_increment_stat) (h, BIHASH_STAT_linear, 1);
  	}
        BV (clib_bihash_increment_stat) (h, BIHASH_STAT_resplit, 1);
        BV (clib_bihash_increment_stat) (h, BIHASH_STAT_splits,
  				       old_log2_pages + 1);
      }
  
    /* Try to add the new entry */
    save_new_v = new_v;
    new_hash = BV (clib_bihash_hash) (add_v);
    limit = BIHASH_KVP_PER_PAGE;
    if (mark_bucket_linear)
      limit <<= new_log2_pages;
    new_hash >>= h->log2_nbuckets;
    new_hash &= (1 << new_log2_pages) - 1;
    new_v += mark_bucket_linear ? 0 : new_hash;
  
    for (i = 0; i < limit; i++)
      {
        if (BV (clib_bihash_is_free) (&(new_v->kvp[i])))
  	{
  	  clib_memcpy_fast (&(new_v->kvp[i]), add_v, sizeof (*add_v));
  	  goto expand_ok;
  	}
      }
  
    /* Crap. Try again */
    BV (value_free) (h, save_new_v, new_log2_pages);
    /*
     * If we've already doubled the size of the bucket once,
     * fall back to linear search now.
     */
    if (resplit_once)
      goto mark_linear;
    else
      goto try_resplit;
  
  expand_ok:
    tmp_b.log2_pages = new_log2_pages;
    tmp_b.offset = BV (clib_bihash_get_offset) (h, save_new_v);
    tmp_b.linear_search = mark_bucket_linear;
    tmp_b.refcnt = h->saved_bucket.refcnt + 1;
    ASSERT (tmp_b.refcnt > 0);
    tmp_b.lock = 0;
    CLIB_MEMORY_BARRIER ();
    b->as_u64 = tmp_b.as_u64;
    /* free the old bucket */
    v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
    BV (value_free) (h, v, h->saved_bucket.log2_pages);
    BV (clib_bihash_alloc_unlock) (h);
    return (0);
  }
  
  int BV (clib_bihash_add_del)
    (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add)
  {
    return BV (clib_bihash_add_del_inline) (h, add_v, is_add, 0, 0);
  }
  
  int BV (clib_bihash_add_or_overwrite_stale)
    (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v,
     int (*stale_callback) (BVT (clib_bihash_kv) *, void *), void *arg)
  {
    return BV (clib_bihash_add_del_inline) (h, add_v, 1, stale_callback, arg);
  }
  
  int BV (clib_bihash_search)
    (BVT (clib_bihash) * h,
     BVT (clib_bihash_kv) * search_key, BVT (clib_bihash_kv) * valuep)
  {
    u64 hash;
    u32 bucket_index;
    BVT (clib_bihash_value) * v;
    BVT (clib_bihash_bucket) * b;
    int i, limit;
  
    ASSERT (valuep);
  
    if (PREDICT_FALSE (alloc_arena (h) == 0))
      return -1;
  
    hash = BV (clib_bihash_hash) (search_key);
  
    bucket_index = hash & (h->nbuckets - 1);
    b = &h->buckets[bucket_index];
  
    if (BV (clib_bihash_bucket_is_empty) (b))
      return -1;
  
    if (PREDICT_FALSE (b->lock))
      {
        volatile BVT (clib_bihash_bucket) * bv = b;
        while (bv->lock)
  	CLIB_PAUSE ();
      }
  
    hash >>= h->log2_nbuckets;
  
    v = BV (clib_bihash_get_value) (h, b->offset);
    limit = BIHASH_KVP_PER_PAGE;
    v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
    if (PREDICT_FALSE (b->linear_search))
      limit <<= b->log2_pages;
  
    for (i = 0; i < limit; i++)
      {
        if (BV (clib_bihash_key_compare) (v->kvp[i].key, search_key->key))
  	{
  	  *valuep = v->kvp[i];
  	  return 0;
  	}
      }
    return -1;
  }
  
  u8 *BV (format_bihash) (u8 * s, va_list * args)
  {
    BVT (clib_bihash) * h = va_arg (*args, BVT (clib_bihash) *);
    int verbose = va_arg (*args, int);
    BVT (clib_bihash_bucket) * b;
    BVT (clib_bihash_value) * v;
    int i, j, k;
    u64 active_elements = 0;
    u64 active_buckets = 0;
    u64 linear_buckets = 0;
    u64 used_bytes;
  
    s = format (s, "Hash table %s\n", h->name ? h->name : (u8 *) "(unnamed)");
  
    if (PREDICT_FALSE (alloc_arena (h) == 0))
      return format (s, "[empty, uninitialized]");
  
    for (i = 0; i < h->nbuckets; i++)
      {
        b = &h->buckets[i];
        if (BV (clib_bihash_bucket_is_empty) (b))
  	{
  	  if (verbose > 1)
  	    s = format (s, "[%d]: empty\n", i);
  	  continue;
  	}
  
        active_buckets++;
  
        if (b->linear_search)
  	linear_buckets++;
  
        if (verbose)
  	{
  	  s = format (s, "[%d]: heap offset %lld, len %d, linear %d\n", i,
  		      b->offset, (1 << b->log2_pages), b->linear_search);
  	}
  
        v = BV (clib_bihash_get_value) (h, b->offset);
        for (j = 0; j < (1 << b->log2_pages); j++)
  	{
  	  for (k = 0; k < BIHASH_KVP_PER_PAGE; k++)
  	    {
  	      if (BV (clib_bihash_is_free) (&v->kvp[k]))
  		{
  		  if (verbose > 1)
  		    s = format (s, "    %d: empty\n",
  				j * BIHASH_KVP_PER_PAGE + k);
  		  continue;
  		}
  	      if (verbose)
  		{
  		  if (h->fmt_fn)
  		    {
  		      s = format (s, "    %d: %U\n",
  				  j * BIHASH_KVP_PER_PAGE + k,
  				  h->fmt_fn, &(v->kvp[k]), verbose);
  		    }
  		  else
  		    {
  		      s = format (s, "    %d: %U\n",
  				  j * BIHASH_KVP_PER_PAGE + k,
  				  BV (format_bihash_kvp), &(v->kvp[k]));
  		    }
  		}
  	      active_elements++;
  	    }
  	  v++;
  	}
      }
  
    s = format (s, "    %lld active elements %lld active buckets\n",
  	      active_elements, active_buckets);
    s = format (s, "    %d free lists\n", vec_len (h->freelists));
  
    for (i = 0; i < vec_len (h->freelists); i++)
      {
        u32 nfree = 0;
        BVT (clib_bihash_value) * free_elt;
        u64 free_elt_as_u64 = h->freelists[i];
  
        while (free_elt_as_u64)
  	{
  	  free_elt = BV (clib_bihash_get_value) (h, free_elt_as_u64);
  	  nfree++;
  	  free_elt_as_u64 = free_elt->next_free_as_u64;
  	}
  
        if (nfree || verbose)
  	s = format (s, "       [len %d] %u free elts\n", 1 << i, nfree);
      }
  
    s = format (s, "    %lld linear search buckets\n", linear_buckets);
    used_bytes = alloc_arena_next (h);
    s = format (s,
  	      "    arena: base %llx, next %llx\n"
  	      "           used %lld b (%lld Mbytes) of %lld b (%lld Mbytes)\n",
  	      alloc_arena (h), alloc_arena_next (h),
  	      used_bytes, used_bytes >> 20,
  	      alloc_arena_size (h), alloc_arena_size (h) >> 20);
    return s;
  }
  
  void BV (clib_bihash_foreach_key_value_pair)
    (BVT (clib_bihash) * h, void *callback, void *arg)
  {
    int i, j, k;
    BVT (clib_bihash_bucket) * b;
    BVT (clib_bihash_value) * v;
    void (*fp) (BVT (clib_bihash_kv) *, void *) = callback;
  
    if (PREDICT_FALSE (alloc_arena (h) == 0))
      return;
  
    for (i = 0; i < h->nbuckets; i++)
      {
        b = &h->buckets[i];
        if (BV (clib_bihash_bucket_is_empty) (b))
  	continue;
  
        v = BV (clib_bihash_get_value) (h, b->offset);
        for (j = 0; j < (1 << b->log2_pages); j++)
  	{
  	  for (k = 0; k < BIHASH_KVP_PER_PAGE; k++)
  	    {
  	      if (BV (clib_bihash_is_free) (&v->kvp[k]))
  		continue;
  
  	      (*fp) (&v->kvp[k], arg);
  	      /*
  	       * In case the callback deletes the last entry in the bucket...
  	       */
  	      if (BV (clib_bihash_bucket_is_empty) (b))
  		goto doublebreak;
  	    }
  	  v++;
  	}
      doublebreak:
        ;
      }
  }
  
  /** @endcond */
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  