src/vppinfra/bihash_template.c - fdio/vpp - Gitiles

 /*
  * 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 */

 void BV (clib_bihash_init)
   (BVT (clib_bihash) * h, char *name, u32 nbuckets, uword memory_size)
 {
   void *oldheap;
   int i;

   nbuckets = 1 << (max_log2 (nbuckets));

   h->name = (u8 *) name;
   h->nbuckets = nbuckets;
   h->log2_nbuckets = max_log2 (nbuckets);
   h->cache_hits = 0;
   h->cache_misses = 0;

   h->mheap = mheap_alloc (0 /* use VM */ , memory_size);

   oldheap = clib_mem_set_heap (h->mheap);
   vec_validate_aligned (h->buckets, nbuckets - 1, CLIB_CACHE_LINE_BYTES);
   h->writer_lock = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES,
 					   CLIB_CACHE_LINE_BYTES);
   h->writer_lock[0] = 0;

   for (i = 0; i < nbuckets; i++)
     BV (clib_bihash_reset_cache) (h->buckets + i);

   clib_mem_set_heap (oldheap);
 }

 void BV (clib_bihash_free) (BVT (clib_bihash) * h)
 {
   mheap_free (h->mheap);
   memset (h, 0, sizeof (*h));
 }

 static
 BVT (clib_bihash_value) *
 BV (value_alloc) (BVT (clib_bihash) * h, u32 log2_pages)
 {
   BVT (clib_bihash_value) * rv = 0;
   void *oldheap;

   ASSERT (h->writer_lock[0]);
   if (log2_pages >= vec_len (h->freelists) || h->freelists[log2_pages] == 0)
     {
       oldheap = clib_mem_set_heap (h->mheap);

       vec_validate (h->freelists, log2_pages);
       rv = clib_mem_alloc_aligned ((sizeof (*rv) * (1 << log2_pages)),
 				   CLIB_CACHE_LINE_BYTES);
       clib_mem_set_heap (oldheap);
       goto initialize;
     }
   rv = h->freelists[log2_pages];
   h->freelists[log2_pages] = rv->next_free;

 initialize:
   ASSERT (rv);
   /*
    * Latest gcc complains that the length arg is zero
    * if we replace (1<<log2_pages) with vec_len(rv).
    * No clue.
    */
   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->writer_lock[0]);

   ASSERT (vec_len (h->freelists) > log2_pages);

   v->next_free = h->freelists[log2_pages];
   h->freelists[log2_pages] = 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)));
   void *oldheap;
   BVT (clib_bihash_value) * working_copy;
   u32 thread_index = os_get_thread_index ();
   int log2_working_copy_length;

   if (thread_index >= vec_len (h->working_copies))
     {
       oldheap = clib_mem_set_heap (h->mheap);
       vec_validate (h->working_copies, thread_index);
       vec_validate_init_empty (h->working_copy_lengths, thread_index, ~0);
       clib_mem_set_heap (oldheap);
     }

   /*
    * 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;
   oldheap = clib_mem_set_heap (h->mheap);

   if (b->log2_pages > log2_working_copy_length)
     {
       if (working_copy)
 	clib_mem_free (working_copy);

       working_copy = clib_mem_alloc_aligned
 	(sizeof (working_copy[0]) * (1 << b->log2_pages),
 	 CLIB_CACHE_LINE_BYTES);
       h->working_copy_lengths[thread_index] = b->log2_pages;
       h->working_copies[thread_index] = working_copy;
     }

   clib_mem_set_heap (oldheap);

   /* Lock the bucket... */
   while (BV (clib_bihash_lock_bucket) (b) == 0)
     ;

   v = BV (clib_bihash_get_value) (h, b->offset);

   clib_memcpy (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;

   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 (&(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;

   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 (&(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;
 }

 int BV (clib_bihash_add_del)
   (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add)
 {
   u32 bucket_index;
   BVT (clib_bihash_bucket) * b, tmp_b;
   BVT (clib_bihash_value) * v, *new_v, *save_new_v, *working_copy;
   int rv = 0;
   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;

   hash = BV (clib_bihash_hash) (add_v);

   bucket_index = hash & (h->nbuckets - 1);
   b = &h->buckets[bucket_index];

   hash >>= h->log2_nbuckets;

   tmp_b.linear_search = 0;

   while (__sync_lock_test_and_set (h->writer_lock, 1))
     ;

   /* First elt in the bucket? */
   if (b->offset == 0)
     {
       if (is_add == 0)
 	{
 	  rv = -1;
 	  goto unlock;
 	}

       v = BV (value_alloc) (h, 0);

       *v->kvp = *add_v;
       tmp_b.as_u64 = 0;
       tmp_b.offset = BV (clib_bihash_get_offset) (h, v);

       b->as_u64 = tmp_b.as_u64;
       goto unlock;
     }

   /* Note: this leaves the cache disabled */
   BV (make_working_copy) (h, b);

   v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);

   limit = BIHASH_KVP_PER_PAGE;
   v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
   if (b->linear_search)
     limit <<= b->log2_pages;

   if (is_add)
     {
       /*
        * 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 (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
 	    {
 	      clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
 	      CLIB_MEMORY_BARRIER ();
 	      /* Restore the previous (k,v) pairs */
 	      b->as_u64 = h->saved_bucket.as_u64;
 	      goto unlock;
 	    }
 	}
       for (i = 0; i < limit; i++)
 	{
 	  if (BV (clib_bihash_is_free) (&(v->kvp[i])))
 	    {
 	      clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
 	      CLIB_MEMORY_BARRIER ();
 	      b->as_u64 = h->saved_bucket.as_u64;
 	      goto unlock;
 	    }
 	}
       /* no room at the inn... split case... */
     }
   else
     {
       for (i = 0; i < limit; i++)
 	{
 	  if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
 	    {
 	      memset (&(v->kvp[i]), 0xff, sizeof (*(add_v)));
 	      CLIB_MEMORY_BARRIER ();
 	      b->as_u64 = h->saved_bucket.as_u64;
 	      goto unlock;
 	    }
 	}
       rv = -3;
       b->as_u64 = h->saved_bucket.as_u64;
       goto unlock;
     }

   old_log2_pages = h->saved_bucket.log2_pages;
   new_log2_pages = old_log2_pages + 1;
   mark_bucket_linear = 0;

   working_copy = h->working_copies[thread_index];
   resplit_once = 0;

   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;
 	}
     }

   /* 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 (&(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:
   /* Keep track of the number of linear-scan buckets */
   if (tmp_b.linear_search ^ mark_bucket_linear)
     h->linear_buckets += (mark_bucket_linear == 1) ? 1 : -1;

   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;

   CLIB_MEMORY_BARRIER ();
   b->as_u64 = tmp_b.as_u64;
   v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
   BV (value_free) (h, v, old_log2_pages);

 unlock:
   BV (clib_bihash_reset_cache) (b);
   BV (clib_bihash_unlock_bucket) (b);
   CLIB_MEMORY_BARRIER ();
   h->writer_lock[0] = 0;
   return rv;
 }

 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;
 #if BIHASH_KVP_CACHE_SIZE > 0
   BVT (clib_bihash_kv) * kvp;
 #endif
   BVT (clib_bihash_bucket) * b;
   int i, limit;

   ASSERT (valuep);

   hash = BV (clib_bihash_hash) (search_key);

   bucket_index = hash & (h->nbuckets - 1);
   b = &h->buckets[bucket_index];

   if (b->offset == 0)
     return -1;

 #if BIHASH_KVP_CACHE_SIZE > 0
   /* Check the cache, if currently enabled */
   if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
     {
       limit = BIHASH_KVP_CACHE_SIZE;
       kvp = b->cache;
       for (i = 0; i < limit; i++)
 	{
 	  if (BV (clib_bihash_key_compare) (kvp[i].key, search_key->key))
 	    {
 	      *valuep = kvp[i];
 	      h->cache_hits++;
 	      return 0;
 	    }
 	}
     }
 #endif

   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];

 #if BIHASH_KVP_CACHE_SIZE > 0
 	  u8 cache_slot;
 	  /* Shut off the cache */
 	  if (BV (clib_bihash_lock_bucket) (b))
 	    {
 	      cache_slot = BV (clib_bihash_get_lru) (b);
 	      b->cache[cache_slot] = v->kvp[i];
 	      BV (clib_bihash_update_lru) (b, cache_slot);

 	      /* Reenable the cache */
 	      BV (clib_bihash_unlock_bucket) (b);
 	      h->cache_misses++;
 	    }
 #endif
 	  return 0;
 	}
     }
   return -1;
 }

 u8 *BV (format_bihash_lru) (u8 * s, va_list * args)
 {
 #if BIHASH_KVP_SIZE > 0
   int i;
   BVT (clib_bihash_bucket) * b = va_arg (*args, BVT (clib_bihash_bucket) *);
   u16 cache_lru = b->cache_lru;

   s = format (s, "cache %s, order ", cache_lru & (1 << 15) ? "on" : "off");

   for (i = 0; i < BIHASH_KVP_CACHE_SIZE; i++)
     s = format (s, "[%d] ", ((cache_lru >> (3 * i)) & 7));

   return (s);
 #else
   return format (s, "cache not configured");
 #endif
 }

 void
 BV (clib_bihash_update_lru_not_inline) (BVT (clib_bihash_bucket) * b, u8 slot)
 {
 #if BIHASH_KVP_SIZE > 0
   BV (clib_bihash_update_lru) (b, slot);
 #endif
 }

 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;

   s = format (s, "Hash table %s\n", h->name ? h->name : (u8 *) "(unnamed)");

   for (i = 0; i < h->nbuckets; i++)
     {
       b = &h->buckets[i];
       if (b->offset == 0)
 	{
 	  if (verbose > 1)
 	    s = format (s, "[%d]: empty\n", i);
 	  continue;
 	}

       if (verbose)
 	{
 	  s = format (s, "[%d]: heap offset %d, 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)
 		{
 		  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\n", active_elements);
   s = format (s, "    %d free lists\n", vec_len (h->freelists));
   s = format (s, "    %d linear search buckets\n", h->linear_buckets);
   s = format (s, "    %lld cache hits, %lld cache misses\n",
 	      h->cache_hits, h->cache_misses);
   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;

   for (i = 0; i < h->nbuckets; i++)
     {
       b = &h->buckets[i];
       if (b->offset == 0)
 	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);
 	    }
 	  v++;
 	}
     }
 }

 /** @endcond */

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* 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 */

	void BV (clib_bihash_init)
	(BVT (clib_bihash) * h, char *name, u32 nbuckets, uword memory_size)
	{
	void *oldheap;
	int i;

	nbuckets = 1 << (max_log2 (nbuckets));

	h->name = (u8 *) name;
	h->nbuckets = nbuckets;
	h->log2_nbuckets = max_log2 (nbuckets);
	h->cache_hits = 0;
	h->cache_misses = 0;

	h->mheap = mheap_alloc (0 /* use VM */ , memory_size);

	oldheap = clib_mem_set_heap (h->mheap);
	vec_validate_aligned (h->buckets, nbuckets - 1, CLIB_CACHE_LINE_BYTES);
	h->writer_lock = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES,
	CLIB_CACHE_LINE_BYTES);
	h->writer_lock[0] = 0;

	for (i = 0; i < nbuckets; i++)
	BV (clib_bihash_reset_cache) (h->buckets + i);

	clib_mem_set_heap (oldheap);
	}

	void BV (clib_bihash_free) (BVT (clib_bihash) * h)
	{
	mheap_free (h->mheap);
	memset (h, 0, sizeof (*h));
	}

	static
	BVT (clib_bihash_value) *
	BV (value_alloc) (BVT (clib_bihash) * h, u32 log2_pages)
	{
	BVT (clib_bihash_value) * rv = 0;
	void *oldheap;

	ASSERT (h->writer_lock[0]);
	if (log2_pages >= vec_len (h->freelists) \|\| h->freelists[log2_pages] == 0)
	{
	oldheap = clib_mem_set_heap (h->mheap);

	vec_validate (h->freelists, log2_pages);
	rv = clib_mem_alloc_aligned ((sizeof (rv) (1 << log2_pages)),
	CLIB_CACHE_LINE_BYTES);
	clib_mem_set_heap (oldheap);
	goto initialize;
	}
	rv = h->freelists[log2_pages];
	h->freelists[log2_pages] = rv->next_free;

	initialize:
	ASSERT (rv);
	/*
	* Latest gcc complains that the length arg is zero
	* if we replace (1<<log2_pages) with vec_len(rv).
	* No clue.
	*/
	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->writer_lock[0]);

	ASSERT (vec_len (h->freelists) > log2_pages);

	v->next_free = h->freelists[log2_pages];
	h->freelists[log2_pages] = 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)));
	void *oldheap;
	BVT (clib_bihash_value) * working_copy;
	u32 thread_index = os_get_thread_index ();
	int log2_working_copy_length;

	if (thread_index >= vec_len (h->working_copies))
	{
	oldheap = clib_mem_set_heap (h->mheap);
	vec_validate (h->working_copies, thread_index);
	vec_validate_init_empty (h->working_copy_lengths, thread_index, ~0);
	clib_mem_set_heap (oldheap);
	}

	/*
	* 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;
	oldheap = clib_mem_set_heap (h->mheap);

	if (b->log2_pages > log2_working_copy_length)
	{
	if (working_copy)
	clib_mem_free (working_copy);

	working_copy = clib_mem_alloc_aligned
	(sizeof (working_copy[0]) * (1 << b->log2_pages),
	CLIB_CACHE_LINE_BYTES);
	h->working_copy_lengths[thread_index] = b->log2_pages;
	h->working_copies[thread_index] = working_copy;
	}

	clib_mem_set_heap (oldheap);

	/* Lock the bucket... */
	while (BV (clib_bihash_lock_bucket) (b) == 0)
	;

	v = BV (clib_bihash_get_value) (h, b->offset);

	clib_memcpy (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;

	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 (&(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;

	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 (&(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;
	}

	int BV (clib_bihash_add_del)
	(BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add)
	{
	u32 bucket_index;
	BVT (clib_bihash_bucket) * b, tmp_b;
	BVT (clib_bihash_value) * v, new_v, save_new_v, *working_copy;
	int rv = 0;
	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;

	hash = BV (clib_bihash_hash) (add_v);

	bucket_index = hash & (h->nbuckets - 1);
	b = &h->buckets[bucket_index];

	hash >>= h->log2_nbuckets;

	tmp_b.linear_search = 0;

	while (__sync_lock_test_and_set (h->writer_lock, 1))
	;

	/* First elt in the bucket? */
	if (b->offset == 0)
	{
	if (is_add == 0)
	{
	rv = -1;
	goto unlock;
	}

	v = BV (value_alloc) (h, 0);

	v->kvp = add_v;
	tmp_b.as_u64 = 0;
	tmp_b.offset = BV (clib_bihash_get_offset) (h, v);

	b->as_u64 = tmp_b.as_u64;
	goto unlock;
	}

	/* Note: this leaves the cache disabled */
	BV (make_working_copy) (h, b);

	v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);

	limit = BIHASH_KVP_PER_PAGE;
	v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
	if (b->linear_search)
	limit <<= b->log2_pages;

	if (is_add)
	{
	/*
	* 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 (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
	{
	clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
	CLIB_MEMORY_BARRIER ();
	/* Restore the previous (k,v) pairs */
	b->as_u64 = h->saved_bucket.as_u64;
	goto unlock;
	}
	}
	for (i = 0; i < limit; i++)
	{
	if (BV (clib_bihash_is_free) (&(v->kvp[i])))
	{
	clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
	CLIB_MEMORY_BARRIER ();
	b->as_u64 = h->saved_bucket.as_u64;
	goto unlock;
	}
	}
	/* no room at the inn... split case... */
	}
	else
	{
	for (i = 0; i < limit; i++)
	{
	if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
	{
	memset (&(v->kvp[i]), 0xff, sizeof (*(add_v)));
	CLIB_MEMORY_BARRIER ();
	b->as_u64 = h->saved_bucket.as_u64;
	goto unlock;
	}
	}
	rv = -3;
	b->as_u64 = h->saved_bucket.as_u64;
	goto unlock;
	}

	old_log2_pages = h->saved_bucket.log2_pages;
	new_log2_pages = old_log2_pages + 1;
	mark_bucket_linear = 0;

	working_copy = h->working_copies[thread_index];
	resplit_once = 0;

	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;
	}
	}

	/* 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 (&(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:
	/* Keep track of the number of linear-scan buckets */
	if (tmp_b.linear_search ^ mark_bucket_linear)
	h->linear_buckets += (mark_bucket_linear == 1) ? 1 : -1;

	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;

	CLIB_MEMORY_BARRIER ();
	b->as_u64 = tmp_b.as_u64;
	v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
	BV (value_free) (h, v, old_log2_pages);

	unlock:
	BV (clib_bihash_reset_cache) (b);
	BV (clib_bihash_unlock_bucket) (b);
	CLIB_MEMORY_BARRIER ();
	h->writer_lock[0] = 0;
	return rv;
	}

	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;
	#if BIHASH_KVP_CACHE_SIZE > 0
	BVT (clib_bihash_kv) * kvp;
	#endif
	BVT (clib_bihash_bucket) * b;
	int i, limit;

	ASSERT (valuep);

	hash = BV (clib_bihash_hash) (search_key);

	bucket_index = hash & (h->nbuckets - 1);
	b = &h->buckets[bucket_index];

	if (b->offset == 0)
	return -1;

	#if BIHASH_KVP_CACHE_SIZE > 0
	/* Check the cache, if currently enabled */
	if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
	{
	limit = BIHASH_KVP_CACHE_SIZE;
	kvp = b->cache;
	for (i = 0; i < limit; i++)
	{
	if (BV (clib_bihash_key_compare) (kvp[i].key, search_key->key))
	{
	*valuep = kvp[i];
	h->cache_hits++;
	return 0;
	}
	}
	}
	#endif

	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];

	#if BIHASH_KVP_CACHE_SIZE > 0
	u8 cache_slot;
	/* Shut off the cache */
	if (BV (clib_bihash_lock_bucket) (b))
	{
	cache_slot = BV (clib_bihash_get_lru) (b);
	b->cache[cache_slot] = v->kvp[i];
	BV (clib_bihash_update_lru) (b, cache_slot);

	/* Reenable the cache */
	BV (clib_bihash_unlock_bucket) (b);
	h->cache_misses++;
	}
	#endif
	return 0;
	}
	}
	return -1;
	}

	u8 BV (format_bihash_lru) (u8 s, va_list * args)
	{
	#if BIHASH_KVP_SIZE > 0
	int i;
	BVT (clib_bihash_bucket) * b = va_arg (args, BVT (clib_bihash_bucket) );
	u16 cache_lru = b->cache_lru;

	s = format (s, "cache %s, order ", cache_lru & (1 << 15) ? "on" : "off");

	for (i = 0; i < BIHASH_KVP_CACHE_SIZE; i++)
	s = format (s, "[%d] ", ((cache_lru >> (3 * i)) & 7));

	return (s);
	#else
	return format (s, "cache not configured");
	#endif
	}

	void
	BV (clib_bihash_update_lru_not_inline) (BVT (clib_bihash_bucket) * b, u8 slot)
	{
	#if BIHASH_KVP_SIZE > 0
	BV (clib_bihash_update_lru) (b, slot);
	#endif
	}

	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;

	s = format (s, "Hash table %s\n", h->name ? h->name : (u8 *) "(unnamed)");

	for (i = 0; i < h->nbuckets; i++)
	{
	b = &h->buckets[i];
	if (b->offset == 0)
	{
	if (verbose > 1)
	s = format (s, "[%d]: empty\n", i);
	continue;
	}

	if (verbose)
	{
	s = format (s, "[%d]: heap offset %d, 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)
	{
	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\n", active_elements);
	s = format (s, " %d free lists\n", vec_len (h->freelists));
	s = format (s, " %d linear search buckets\n", h->linear_buckets);
	s = format (s, " %lld cache hits, %lld cache misses\n",
	h->cache_hits, h->cache_misses);
	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;

	for (i = 0; i < h->nbuckets; i++)
	{
	b = &h->buckets[i];
	if (b->offset == 0)
	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);
	}
	v++;
	}
	}
	}

	/** @endcond */

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/