aboutsummaryrefslogtreecommitdiffstats
path: root/src/vppinfra/bihash_template.c
blob: d488b1a659caace9c82a397ee3f2975c09f8415c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
.highlight .nv { color: #336699 } /* Name.Variable */
.highlight .ow { color: #008800 } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */
.highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */
.highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */
.highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */
.highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */
.highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */
.highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */
.highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */
.highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */
.highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */
.highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */
.highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */
.highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */
.highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */
.highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */
.highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */
.highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */
.highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */
.highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
.highlight .vc { color: #336699 } /* Name.Variable.Class */
.highlight .vg { color: #dd7700 } /* Name.Variable.Global */
.highlight .vi { color: #3333bb } /* Name.Variable.Instance */
.highlight .vm { color: #336699 } /* Name.Variable.Magic */
.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */
/*
 * Copyright (c) 2018 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.
 */

#ifndef included_palloc_h
#define included_palloc_h
#include <vppinfra/format.h>
#include <vppinfra/pool.h>

#define PMALLOC_LOG2_BLOCK_SZ          CLIB_LOG2_CACHE_LINE_BYTES
#define PMALLOC_BLOCK_SZ               (1 << 6)

#define CLIB_PMALLOC_NUMA_LOCAL 0xffffffff

typedef struct
{
  u32 start, prev, next;
  u32 size:31;
  u32 used:1;
} clib_pmalloc_chunk_t;

STATIC_ASSERT_SIZEOF (clib_pmalloc_chunk_t, 16);

typedef struct
{
  u32 index;
  u32 arena_index;
  clib_pmalloc_chunk_t *chunks;
  u32 first_chunk_index;
  u32 n_free_chunks;
  u32 n_free_blocks;
} clib_pmalloc_page_t;

typedef struct
{
  u32 index;
  u32 flags;
#define CLIB_PMALLOC_ARENA_F_SHARED_MEM (1 << 0)
  int fd;
  u32 numa_node;
  u32 first_page_index;
  u32 log2_subpage_sz;
  u32 subpages_per_page;
  u32 n_pages;
  u8 *name;
  u32 *page_indices;
} clib_pmalloc_arena_t;

typedef struct
{
  /* flags */
  u32 flags;
#define CLIB_PMALLOC_F_NO_PAGEMAP (1 << 0)

  /* base VA address */
  u8 *base;

  /* default page size - typically 2M */
  clib_mem_page_sz_t def_log2_page_sz;

  /* maximum number of pages, limited by VA preallocation size */
  u32 max_pages;

  /* vector of pages - each page have own alloc pool and it can be split
     into subpages (i.e. 2M page build out of 512 4K pages) */
  clib_pmalloc_page_t *pages;

  /* hash used to find chunk index out of VA, chunk index is defined
     per page */
  uword *chunk_index_by_va;

  /* alloc arenas are group of pages which share same attributes
     shared arenas are represented by FD and they are not grovable
     private arenas are growable */
  clib_pmalloc_arena_t *arenas;

  /* vector of per numa node alloc arena indices
     each numa node have own default privat alloc arena */
  u32 *default_arena_for_numa_node;

  /* VA to PA lookup table */
  uword *lookup_table;

  /* lookup page size - equals to smalles subpage used */
  u32 lookup_log2_page_sz;

  /* last error */
  clib_error_t *error;
} clib_pmalloc_main_t;


int clib_pmalloc_init (clib_pmalloc_main_t * pm, uword base_addr, uword size);
void *clib_pmalloc_alloc_aligned_on_numa (clib_pmalloc_main_t * pm,
					  uword size, uword align,
					  u32 numa_node);
void *clib_pmalloc_alloc_aligned (clib_pmalloc_main_t * pm, uword size,
				  uword align);
void clib_pmalloc_free (clib_pmalloc_main_t * pm, void *va);

void *clib_pmalloc_create_shared_arena (clib_pmalloc_main_t * pm, char *name,
					uword size, u32 log2_page_sz,
					u32 numa_node);

void *clib_pmalloc_alloc_from_arena (clib_pmalloc_main_t * pm, void *arena_va,
				     uword size, uword align);

format_function_t format_pmalloc;
format_function_t format_pmalloc_map;

always_inline clib_error_t *
clib_pmalloc_last_error (clib_pmalloc_main_t * pm)
{
  return pm->error;
}

always_inline u32
clib_pmalloc_get_page_index (clib_pmalloc_main_t * pm, void *va)
{
  uword index = (pointer_to_uword (va) - pointer_to_uword (pm->base)) >>
    pm->def_log2_page_sz;

  ASSERT (index < vec_len (pm->pages));

  return index;
}

always_inline clib_pmalloc_arena_t *
clib_pmalloc_get_arena (clib_pmalloc_main_t * pm, void *va)
{
  u32 index = clib_pmalloc_get_page_index (pm, va);
  return pm->arenas + pm->pages[index].arena_index;
}

always_inline uword
clib_pmalloc_get_pa (clib_pmalloc_main_t * pm, void *va)
{
  uword index = (pointer_to_uword (va) - pointer_to_uword (pm->base)) >>
    pm->lookup_log2_page_sz;
  return pointer_to_uword (va) - pm->lookup_table[index];
}


#endif /* included_palloc_h */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */
2 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244
/*
 * 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 */

#ifndef MAP_HUGE_SHIFT
#define MAP_HUGE_SHIFT 26
#endif

#ifndef BIIHASH_MIN_ALLOC_LOG2_PAGES
#define BIIHASH_MIN_ALLOC_LOG2_PAGES 10
#endif

#ifndef BIHASH_USE_HEAP
#define BIHASH_USE_HEAP 1
#endif

static inline void *BV (alloc_aligned) (BVT (clib_bihash) * h, uword nbytes)
{
  uword rv;

  /* Round to an even number of cache lines */
  nbytes = round_pow2 (nbytes, CLIB_CACHE_LINE_BYTES);

  if (BIHASH_USE_HEAP)
    {
      void *rv, *oldheap;
      uword page_sz = sizeof (BVT (clib_bihash_value));
      uword chunk_sz = round_pow2 (page_sz << BIIHASH_MIN_ALLOC_LOG2_PAGES,
				   CLIB_CACHE_LINE_BYTES);

      BVT (clib_bihash_alloc_chunk) * chunk = h->chunks;

      /* if there is enough space in the currenrt chunk */
      if (chunk && chunk->bytes_left >= nbytes)
	{
	  rv = chunk->next_alloc;
	  chunk->bytes_left -= nbytes;
	  chunk->next_alloc += nbytes;
	  return rv;
	}

      /* requested allocation is bigger than chunk size */
      if (nbytes >= chunk_sz)
	{
	  oldheap = clib_mem_set_heap (h->heap);
	  chunk = clib_mem_alloc_aligned (nbytes + sizeof (*chunk),
					  CLIB_CACHE_LINE_BYTES);
	  clib_mem_set_heap (oldheap);
	  clib_memset_u8 (chunk, 0, sizeof (*chunk));
	  chunk->size = nbytes;
	  rv = (u8 *) (chunk + 1);
	  if (h->chunks)
	    {
	      /* take 2nd place in the list */
	      chunk->next = h->chunks->next;
	      chunk->prev = h->chunks;
	      h->chunks->next = chunk;
	      if (chunk->next)
		chunk->next->prev = chunk;
	    }
	  else
	    h->chunks = chunk;

	  return rv;
	}

      oldheap = clib_mem_set_heap (h->heap);
      chunk = clib_mem_alloc_aligned (chunk_sz + sizeof (*chunk),
				      CLIB_CACHE_LINE_BYTES);
      clib_mem_set_heap (oldheap);
      chunk->size = chunk_sz;
      chunk->bytes_left = chunk_sz;
      chunk->next_alloc = (u8 *) (chunk + 1);
      chunk->next = h->chunks;
      chunk->prev = 0;
      if (chunk->next)
	chunk->next->prev = chunk;
      h->chunks = chunk;
      rv = chunk->next_alloc;
      chunk->bytes_left -= nbytes;
      chunk->next_alloc += nbytes;
      return rv;
    }

  rv = alloc_arena_next (h);
  alloc_arena_next (h) += nbytes;

  if (alloc_arena_next (h) > alloc_arena_size (h))
    os_out_of_memory ();

  if (alloc_arena_next (h) > alloc_arena_mapped (h))
    {
      void *base, *rv;
      uword alloc = alloc_arena_next (h) - alloc_arena_mapped (h);
      int mmap_flags = MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS;
#if __linux__
      int mmap_flags_huge = (mmap_flags | MAP_HUGETLB | MAP_LOCKED |
			     BIHASH_LOG2_HUGEPAGE_SIZE << MAP_HUGE_SHIFT);
#endif /* __linux__ */

      /* new allocation is 25% of existing one */
      if (alloc_arena_mapped (h) >> 2 > alloc)
	alloc = alloc_arena_mapped (h) >> 2;

      /* round allocation to page size */
      alloc = round_pow2 (alloc, 1 << BIHASH_LOG2_HUGEPAGE_SIZE);

      base = (void *) (uword) (alloc_arena (h) + alloc_arena_mapped (h));

#if __linux__
      rv = mmap (base, alloc, PROT_READ | PROT_WRITE, mmap_flags_huge, -1, 0);
#elif __FreeBSD__
      rv = MAP_FAILED;
#endif /* __linux__ */

      /* fallback - maybe we are still able to allocate normal pages */
      if (rv == MAP_FAILED || mlock (base, alloc) != 0)
	rv = mmap (base, alloc, PROT_READ | PROT_WRITE, mmap_flags, -1, 0);

      if (rv == MAP_FAILED)
	os_out_of_memory ();

      alloc_arena_mapped (h) += alloc;
    }

  return (void *) (uword) (rv + alloc_arena (h));
}

static void BV (clib_bihash_instantiate) (BVT (clib_bihash) * h)
{
  uword bucket_size;

  if (BIHASH_USE_HEAP)
    {
      h->heap = clib_mem_get_heap ();
      h->chunks = 0;
      alloc_arena (h) = (uword) clib_mem_get_heap_base (h->heap);
    }
  else
    {
      alloc_arena (h) = clib_mem_vm_reserve (0, h->memory_size,
					     BIHASH_LOG2_HUGEPAGE_SIZE);
      if (alloc_arena (h) == ~0)
	os_out_of_memory ();
      alloc_arena_next (h) = 0;
      alloc_arena_size (h) = h->memory_size;
      alloc_arena_mapped (h) = 0;
    }

  bucket_size = h->nbuckets * sizeof (h->buckets[0]);

  if (BIHASH_KVP_AT_BUCKET_LEVEL)
    bucket_size +=
      h->nbuckets * BIHASH_KVP_PER_PAGE * sizeof (BVT (clib_bihash_kv));

  h->buckets = BV (alloc_aligned) (h, bucket_size);
  clib_memset_u8 (h->buckets, 0, bucket_size);

  if (BIHASH_KVP_AT_BUCKET_LEVEL)
    {
      int i, j;
      BVT (clib_bihash_bucket) * b;

      b = h->buckets;

      for (i = 0; i < h->nbuckets; i++)
	{
	  BVT (clib_bihash_kv) * v;
	  b->offset = BV (clib_bihash_get_offset) (h, (void *) (b + 1));
	  b->refcnt = 1;
	  /* Mark all elements free */
	  v = (void *) (b + 1);
	  for (j = 0; j < BIHASH_KVP_PER_PAGE; j++)
	    {
	      BV (clib_bihash_mark_free) (v);
	      v++;
	    }
	  /* Compute next bucket start address */
	  b = (void *) (((uword) b) + sizeof (*b) +
			(BIHASH_KVP_PER_PAGE *
			 sizeof (BVT (clib_bihash_kv))));
	}
    }
  CLIB_MEMORY_STORE_BARRIER ();
  h->instantiated = 1;
}

void BV (clib_bihash_init2) (BVT (clib_bihash_init2_args) * a)
{
  int i;
  void *oldheap;
  BVT (clib_bihash) * h = a->h;

  a->nbuckets = 1 << (max_log2 (a->nbuckets));

  h->name = (u8 *) a->name;
  h->nbuckets = a->nbuckets;
  h->log2_nbuckets = max_log2 (a->nbuckets);
  h->memory_size = BIHASH_USE_HEAP ? 0 : a->memory_size;
  h->instantiated = 0;
  h->dont_add_to_all_bihash_list = a->dont_add_to_all_bihash_list;
  h->fmt_fn = BV (format_bihash);
  h->kvp_fmt_fn = a->kvp_fmt_fn;

  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...
   */
  if (BIHASH_USE_HEAP)
    ASSERT (h->memory_size < (1ULL << BIHASH_BUCKET_OFFSET_BITS));

  /* Add this hash table to the list */
  if (a->dont_add_to_all_bihash_list == 0)
    {
      for (i = 0; i < vec_len (clib_all_bihashes); i++)
	if (clib_all_bihashes[i] == h)
	  goto do_lock;
      oldheap = clib_all_bihash_set_heap ();
      vec_add1 (clib_all_bihashes, (void *) h);
      clib_mem_set_heap (oldheap);
    }

do_lock:
  if (h->alloc_lock)
    clib_mem_free ((void *) h->alloc_lock);

  /*
   * Set up the lock now, so we can use it to make the first add
   * thread-safe
   */
  h->alloc_lock = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES,
					  CLIB_CACHE_LINE_BYTES);
  h->alloc_lock[0] = 0;

#if BIHASH_LAZY_INSTANTIATE
  if (a->instantiate_immediately)
#endif
    BV (clib_bihash_instantiate) (h);
}

void BV (clib_bihash_init)
  (BVT (clib_bihash) * h, char *name, u32 nbuckets, uword memory_size)
{
  BVT (clib_bihash_init2_args) _a, *a = &_a;

  memset (a, 0, sizeof (*a));

  a->h = h;
  a->name = name;
  a->nbuckets = nbuckets;
  a->memory_size = memory_size;

  BV (clib_bihash_init2) (a);
}

#if BIHASH_32_64_SVM
#if !defined (MFD_ALLOW_SEALING)
#define MFD_ALLOW_SEALING 0x0002U
#endif

void BV (clib_bihash_initiator_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 (BIHASH_USE_HEAP == 0);

  ASSERT (memory_size < (1ULL << 32));
  /* Set up for memfd sharing */
  if ((fd = clib_mem_vm_create_fd (CLIB_MEM_PAGE_SZ_DEFAULT, name) == -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);
  clib_memset_u8 (h->buckets, 0, 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;
  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 = BV (format_bihash);
  h->kvp_fmt_fn = NULL;
  h->instantiated = 1;
}

void BV (clib_bihash_responder_init_svm)
  (BVT (clib_bihash) * h, char *name, int fd)
{
  u8 *mmap_addr;
  u64 memory_size;
  BVT (clib_bihash_shared_header) * sh;

  ASSERT (BIHASH_USE_HEAP == 0);

  /* 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 = BV (format_bihash);
  h->kvp_fmt_fn = NULL;
}
#endif /* BIHASH_32_64_SVM */

void BV (clib_bihash_set_kvp_format_fn) (BVT (clib_bihash) * h,
					 format_function_t * kvp_fmt_fn)
{
  h->kvp_fmt_fn = kvp_fmt_fn;
}

int BV (clib_bihash_is_initialised) (const BVT (clib_bihash) * h)
{
  return (h->instantiated != 0);
}

void BV (clib_bihash_free) (BVT (clib_bihash) * h)
{
  int i;

  if (PREDICT_FALSE (h->instantiated == 0))
    goto never_initialized;

  h->instantiated = 0;

  if (BIHASH_USE_HEAP)
    {
      BVT (clib_bihash_alloc_chunk) * next, *chunk;
      void *oldheap = clib_mem_set_heap (h->heap);

      chunk = h->chunks;
      while (chunk)
	{
	  next = chunk->next;
	  clib_mem_free (chunk);
	  chunk = next;
	}
      clib_mem_set_heap (oldheap);
    }

  vec_free (h->working_copies);
  vec_free (h->working_copy_lengths);
  clib_mem_free ((void *) h->alloc_lock);
#if BIHASH_32_64_SVM == 0
  vec_free (h->freelists);
#else
  if (h->memfd > 0)
    (void) close (h->memfd);
#endif
  if (BIHASH_USE_HEAP == 0)
    clib_mem_vm_free ((void *) (uword) (alloc_arena (h)),
		      alloc_arena_size (h));
never_initialized:
  if (h->dont_add_to_all_bihash_list)
    {
      clib_memset_u8 (h, 0, sizeof (*h));
      return;
    }
  clib_memset_u8 (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) (uword) h);
}

static
BVT (clib_bihash_value) *
BV (value_alloc) (BVT (clib_bihash) * h, u32 log2_pages)
{
  int i;
  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);

  BVT (clib_bihash_kv) * v;
  v = (BVT (clib_bihash_kv) *) rv;

  for (i = 0; i < BIHASH_KVP_PER_PAGE * (1 << log2_pages); i++)
    {
      BV (clib_bihash_mark_free) (v);
      v++;
    }
  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 (BIHASH_USE_HEAP && log2_pages >= BIIHASH_MIN_ALLOC_LOG2_PAGES)
    {
      /* allocations bigger or equal to chunk size always contain single
       * alloc and they can be given back to heap */
      void *oldheap;
      BVT (clib_bihash_alloc_chunk) * c;
      c = (BVT (clib_bihash_alloc_chunk) *) v - 1;

      if (c->prev)
	c->prev->next = c->next;
      else
	h->chunks = c->next;

      if (c->next)
	c->next->prev = c->prev;

      oldheap = clib_mem_set_heap (h->heap);
      clib_mem_free (c);
      clib_mem_set_heap (oldheap);
      return;
    }

  if (CLIB_DEBUG > 0)
    clib_memset_u8 (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_STORE_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 = extract_bits (new_hash, h->log2_nbuckets, new_log2_pages);
      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_always_inline int BV (clib_bihash_add_del_inline_with_hash) (
  BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, u64 hash, int is_add,
  int (*is_stale_cb) (BVT (clib_bihash_kv) *, void *), void *is_stale_arg,
  void (*overwrite_cb) (BVT (clib_bihash_kv) *, void *), void *overwrite_arg)
{
  BVT (clib_bihash_bucket) * b, tmp_b;
  BVT (clib_bihash_value) * v, *new_v, *save_new_v, *working_copy;
  int i, limit;
  u64 new_hash;
  u32 new_log2_pages, old_log2_pages;
  u32 thread_index = os_get_thread_index ();
  int mark_bucket_linear;
  int resplit_once;

  static const BVT (clib_bihash_bucket) mask = {
    .linear_search = 1,
    .log2_pages = -1
  };

#if BIHASH_LAZY_INSTANTIATE
  /*
   * Create the table (is_add=1,2), or flunk the request now (is_add=0)
   * Use the alloc_lock to protect the instantiate operation.
   */
  if (PREDICT_FALSE (h->instantiated == 0))
    {
      if (is_add == 0)
	return (-1);

      BV (clib_bihash_alloc_lock) (h);
      if (h->instantiated == 0)
	BV (clib_bihash_instantiate) (h);
      BV (clib_bihash_alloc_unlock) (h);
    }
#else
  /* Debug image: make sure the table has been instantiated */
  ASSERT (h->instantiated != 0);
#endif

  /*
   * Debug image: make sure that an item being added doesn't accidentally
   * look like a free item.
   */
  ASSERT ((is_add && BV (clib_bihash_is_free) (add_v)) == 0);

  b = BV (clib_bihash_get_bucket) (h, hash);

  BV (clib_bihash_lock_bucket) (b);

  /* First elt in the bucket? */
  if (BIHASH_KVP_AT_BUCKET_LEVEL == 0 && 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_STORE_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);

  if (PREDICT_FALSE (b->as_u64 & mask.as_u64))
    {
      if (PREDICT_FALSE (b->linear_search))
	limit <<= b->log2_pages;
      else
	v += extract_bits (hash, h->log2_nbuckets, 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_is_free) (&(v->kvp[i])))
	    continue;
	  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);
		}
	      if (overwrite_cb)
		overwrite_cb (&(v->kvp[i]), overwrite_arg);
	      clib_memcpy_fast (&(v->kvp[i].value),
				&add_v->value, sizeof (add_v->value));
	      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_STORE_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]), is_stale_arg))
		{
		  clib_memcpy_fast (&(v->kvp[i]), add_v, sizeof (*add_v));
		  CLIB_MEMORY_STORE_BARRIER ();
		  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++)
	{
	  /* no sense even looking at this one */
	  if (BV (clib_bihash_is_free) (&(v->kvp[i])))
	    continue;
	  /* Found the key? Kill it... */
	  if (BV (clib_bihash_key_compare) (v->kvp[i].key, add_v->key))
	    {
	      BV (clib_bihash_mark_free) (&(v->kvp[i]));
	      /* Is the bucket empty? */
	      if (PREDICT_TRUE (b->refcnt > 1))
		{
		  b->refcnt--;
		  /* Switch back to the bucket-level kvp array? */
		  if (BIHASH_KVP_AT_BUCKET_LEVEL && b->refcnt == 1
		      && b->log2_pages > 0)
		    {
		      tmp_b.as_u64 = b->as_u64;
		      b->offset = BV (clib_bihash_get_offset)
			(h, (void *) (b + 1));
		      b->linear_search = 0;
		      b->log2_pages = 0;
		      /* Clean up the bucket-level kvp array */
		      BVT (clib_bihash_kv) *v = (void *) (b + 1);
		      int j;
		      for (j = 0; j < BIHASH_KVP_PER_PAGE; j++)
			{
			  BV (clib_bihash_mark_free) (v);
			  v++;
			}
		      CLIB_MEMORY_STORE_BARRIER ();
		      BV (clib_bihash_unlock_bucket) (b);
		      BV (clib_bihash_increment_stat) (h, BIHASH_STAT_del, 1);
		      goto free_backing_store;
		    }

		  CLIB_MEMORY_STORE_BARRIER ();
		  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;

		  /* Kill and unlock the bucket */
		  b->as_u64 = 0;

		free_backing_store:
		  /* 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;
  else
    new_v += extract_bits (new_hash, h->log2_nbuckets, new_log2_pages);

  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;
#if BIHASH_KVP_AT_BUCKET_LEVEL
  /* Compensate for permanent refcount bump at the bucket level */
  if (new_log2_pages > 0)
#endif
    tmp_b.refcnt = h->saved_bucket.refcnt + 1;
  ASSERT (tmp_b.refcnt > 0);
  tmp_b.lock = 0;
  CLIB_MEMORY_STORE_BARRIER ();
  b->as_u64 = tmp_b.as_u64;

#if BIHASH_KVP_AT_BUCKET_LEVEL
  if (h->saved_bucket.log2_pages > 0)
    {
#endif

      /* free the old bucket, except at the bucket level if so configured */
      v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
      BV (value_free) (h, v, h->saved_bucket.log2_pages);

#if BIHASH_KVP_AT_BUCKET_LEVEL
    }
#endif


  BV (clib_bihash_alloc_unlock) (h);
  return (0);
}

static_always_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)
{
  u64 hash = BV (clib_bihash_hash) (add_v);
  return BV (clib_bihash_add_del_inline_with_hash) (h, add_v, hash, is_add,
						    is_stale_cb, arg, 0, 0);
}

int BV (clib_bihash_add_del_with_hash) (BVT (clib_bihash) * h,
					BVT (clib_bihash_kv) * add_v, u64 hash,
					int is_add)
{
  return BV (clib_bihash_add_del_inline_with_hash) (h, add_v, hash, is_add, 0,
						    0, 0, 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_add_with_overwrite_cb) (
  BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v,
  void (overwrite_cb) (BVT (clib_bihash_kv) *, void *), void *arg)
{
  u64 hash = BV (clib_bihash_hash) (add_v);
  return BV (clib_bihash_add_del_inline_with_hash) (h, add_v, hash, 1, 0, 0,
						    overwrite_cb, arg);
}

int BV (clib_bihash_search)
  (BVT (clib_bihash) * h,
   BVT (clib_bihash_kv) * search_key, BVT (clib_bihash_kv) * valuep)
{
  return BV (clib_bihash_search_inline_2) (h, search_key, valuep);
}

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;

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

#if BIHASH_LAZY_INSTANTIATE
  if (PREDICT_FALSE (h->instantiated == 0))
    return format (s, "    empty, uninitialized");
#endif

  for (i = 0; i < h->nbuckets; i++)
    {
      b = BV (clib_bihash_get_bucket) (h, 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, refcnt %d, linear %d\n", i,
	     b->offset, (1 << b->log2_pages), b->refcnt, 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->kvp_fmt_fn)
		    {
		      s = format (s, "    %d: %U\n",
				  j * BIHASH_KVP_PER_PAGE + k,
				  h->kvp_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);
  if (BIHASH_USE_HEAP)
    {
      BVT (clib_bihash_alloc_chunk) * c = h->chunks;
      uword bytes_left = 0, total_size = 0, n_chunks = 0;

      while (c)
	{
	  bytes_left += c->bytes_left;
	  total_size += c->size;
	  n_chunks += 1;
	  c = c->next;
	}
      s = format (s,
		  "    heap: %u chunk(s) allocated\n"
		  "          bytes: used %U, scrap %U\n", n_chunks,
		  format_memory_size, total_size,
		  format_memory_size, bytes_left);
    }
  else
    {
      u64 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,
   BV (clib_bihash_foreach_key_value_pair_cb) cb, void *arg)
{
  int i, j, k;
  BVT (clib_bihash_bucket) * b;
  BVT (clib_bihash_value) * v;


#if BIHASH_LAZY_INSTANTIATE
  if (PREDICT_FALSE (h->instantiated == 0))
    return;
#endif

  for (i = 0; i < h->nbuckets; i++)
    {
      b = BV (clib_bihash_get_bucket) (h, 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;

	      if (BIHASH_WALK_STOP == cb (&v->kvp[k], arg))
		return;
	      /*
	       * 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:
 */