2 * Copyright (c) 2015 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 /** @cond DOCUMENTATION_IS_IN_BIHASH_DOC_H */
18 void BV (clib_bihash_init)
19 (BVT (clib_bihash) * h, char *name, u32 nbuckets, uword memory_size)
23 nbuckets = 1 << (max_log2 (nbuckets));
25 h->name = (u8 *) name;
26 h->nbuckets = nbuckets;
27 h->log2_nbuckets = max_log2 (nbuckets);
29 h->mheap = mheap_alloc (0 /* use VM */ , memory_size);
31 oldheap = clib_mem_set_heap (h->mheap);
32 vec_validate_aligned (h->buckets, nbuckets - 1, CLIB_CACHE_LINE_BYTES);
33 h->writer_lock = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES,
34 CLIB_CACHE_LINE_BYTES);
36 clib_mem_set_heap (oldheap);
39 void BV (clib_bihash_free) (BVT (clib_bihash) * h)
41 mheap_free (h->mheap);
42 memset (h, 0, sizeof (*h));
46 BVT (clib_bihash_value) *
47 BV (value_alloc) (BVT (clib_bihash) * h, u32 log2_pages)
49 BVT (clib_bihash_value) * rv = 0;
52 ASSERT (h->writer_lock[0]);
53 if (log2_pages >= vec_len (h->freelists) || h->freelists[log2_pages] == 0)
55 oldheap = clib_mem_set_heap (h->mheap);
57 vec_validate (h->freelists, log2_pages);
58 vec_validate_aligned (rv, (1 << log2_pages) - 1, CLIB_CACHE_LINE_BYTES);
59 clib_mem_set_heap (oldheap);
62 rv = h->freelists[log2_pages];
63 h->freelists[log2_pages] = rv->next_free;
67 ASSERT (vec_len (rv) == (1 << log2_pages));
69 * Latest gcc complains that the length arg is zero
70 * if we replace (1<<log2_pages) with vec_len(rv).
73 memset (rv, 0xff, sizeof (*rv) * (1 << log2_pages));
78 BV (value_free) (BVT (clib_bihash) * h, BVT (clib_bihash_value) * v)
82 ASSERT (h->writer_lock[0]);
84 log2_pages = min_log2 (vec_len (v));
86 ASSERT (vec_len (h->freelists) > log2_pages);
88 v->next_free = h->freelists[log2_pages];
89 h->freelists[log2_pages] = v;
93 BV (make_working_copy) (BVT (clib_bihash) * h, clib_bihash_bucket_t * b)
95 BVT (clib_bihash_value) * v;
96 clib_bihash_bucket_t working_bucket __attribute__ ((aligned (8)));
98 BVT (clib_bihash_value) * working_copy;
99 u32 cpu_number = os_get_cpu_number ();
101 if (cpu_number >= vec_len (h->working_copies))
103 oldheap = clib_mem_set_heap (h->mheap);
104 vec_validate (h->working_copies, cpu_number);
105 clib_mem_set_heap (oldheap);
109 * working_copies are per-cpu so that near-simultaneous
110 * updates from multiple threads will not result in sporadic, spurious
113 working_copy = h->working_copies[cpu_number];
115 h->saved_bucket.as_u64 = b->as_u64;
116 oldheap = clib_mem_set_heap (h->mheap);
118 if ((1 << b->log2_pages) > vec_len (working_copy))
120 vec_validate_aligned (working_copy, (1 << b->log2_pages) - 1,
122 h->working_copies[cpu_number] = working_copy;
125 _vec_len (working_copy) = 1 << b->log2_pages;
126 clib_mem_set_heap (oldheap);
128 v = BV (clib_bihash_get_value) (h, b->offset);
130 clib_memcpy (working_copy, v, sizeof (*v) * (1 << b->log2_pages));
131 working_bucket.as_u64 = b->as_u64;
132 working_bucket.offset = BV (clib_bihash_get_offset) (h, working_copy);
133 CLIB_MEMORY_BARRIER ();
134 b->as_u64 = working_bucket.as_u64;
135 h->working_copies[cpu_number] = working_copy;
139 BVT (clib_bihash_value) *
140 BV (split_and_rehash)
141 (BVT (clib_bihash) * h,
142 BVT (clib_bihash_value) * old_values, u32 new_log2_pages)
144 BVT (clib_bihash_value) * new_values, *new_v;
147 new_values = BV (value_alloc) (h, new_log2_pages);
148 length = vec_len (old_values) * BIHASH_KVP_PER_PAGE;
150 for (i = 0; i < length; i++)
154 /* Entry not in use? Forget it */
155 if (BV (clib_bihash_is_free) (&(old_values->kvp[i])))
158 /* rehash the item onto its new home-page */
159 new_hash = BV (clib_bihash_hash) (&(old_values->kvp[i]));
160 new_hash >>= h->log2_nbuckets;
161 new_hash &= (1 << new_log2_pages) - 1;
162 new_v = &new_values[new_hash];
164 /* Across the new home-page */
165 for (j = 0; j < BIHASH_KVP_PER_PAGE; j++)
168 if (BV (clib_bihash_is_free) (&(new_v->kvp[j])))
170 clib_memcpy (&(new_v->kvp[j]), &(old_values->kvp[i]),
171 sizeof (new_v->kvp[j]));
175 /* Crap. Tell caller to try again */
176 BV (value_free) (h, new_values);
184 BVT (clib_bihash_value) *
185 BV (split_and_rehash_linear)
186 (BVT (clib_bihash) * h,
187 BVT (clib_bihash_value) * old_values, u32 new_log2_pages)
189 BVT (clib_bihash_value) * new_values;
190 int i, j, new_length;
192 new_values = BV (value_alloc) (h, new_log2_pages);
193 new_length = (1 << new_log2_pages) * BIHASH_KVP_PER_PAGE;
196 /* Across the old value array */
197 for (i = 0; i < vec_len (old_values) * BIHASH_KVP_PER_PAGE; i++)
199 /* Find a free slot in the new linear scan bucket */
200 for (; j < new_length; j++)
202 /* Old value in use? Forget it. */
203 if (BV (clib_bihash_is_free) (&(old_values->kvp[i])))
206 /* New value should never be in use */
207 if (BV (clib_bihash_is_free) (&(new_values->kvp[j])))
209 /* Copy the old value and move along */
210 clib_memcpy (&(new_values->kvp[j]), &(old_values->kvp[i]),
211 sizeof (new_values->kvp[j]));
215 /* This should never happen... */
216 clib_warning ("BUG: linear rehash failed!");
217 BV (value_free) (h, new_values);
225 int BV (clib_bihash_add_del)
226 (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add)
229 clib_bihash_bucket_t *b, tmp_b;
230 BVT (clib_bihash_value) * v, *new_v, *save_new_v, *working_copy;
235 u32 cpu_number = os_get_cpu_number ();
236 int mark_bucket_linear;
239 hash = BV (clib_bihash_hash) (add_v);
241 bucket_index = hash & (h->nbuckets - 1);
242 b = &h->buckets[bucket_index];
244 hash >>= h->log2_nbuckets;
246 while (__sync_lock_test_and_set (h->writer_lock, 1))
249 /* First elt in the bucket? */
258 v = BV (value_alloc) (h, 0);
261 tmp_b.offset = BV (clib_bihash_get_offset) (h, v);
263 b->as_u64 = tmp_b.as_u64;
267 BV (make_working_copy) (h, b);
269 v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
271 limit = BIHASH_KVP_PER_PAGE;
272 v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
273 if (b->linear_search)
274 limit <<= b->log2_pages;
279 * For obvious (in hindsight) reasons, see if we're supposed to
280 * replace an existing key, then look for an empty slot.
282 for (i = 0; i < limit; i++)
284 if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
286 clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
287 CLIB_MEMORY_BARRIER ();
288 /* Restore the previous (k,v) pairs */
289 b->as_u64 = h->saved_bucket.as_u64;
293 for (i = 0; i < limit; i++)
295 if (BV (clib_bihash_is_free) (&(v->kvp[i])))
297 clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
298 CLIB_MEMORY_BARRIER ();
299 b->as_u64 = h->saved_bucket.as_u64;
303 /* no room at the inn... split case... */
307 for (i = 0; i < limit; i++)
309 if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
311 memset (&(v->kvp[i]), 0xff, sizeof (*(add_v)));
312 CLIB_MEMORY_BARRIER ();
313 b->as_u64 = h->saved_bucket.as_u64;
318 b->as_u64 = h->saved_bucket.as_u64;
322 new_log2_pages = h->saved_bucket.log2_pages + 1;
323 mark_bucket_linear = 0;
325 working_copy = h->working_copies[cpu_number];
328 new_v = BV (split_and_rehash) (h, working_copy, new_log2_pages);
334 /* Try re-splitting. If that fails, fall back to linear search */
335 new_v = BV (split_and_rehash) (h, working_copy, new_log2_pages);
340 /* pinned collisions, use linear search */
342 BV (split_and_rehash_linear) (h, working_copy, new_log2_pages);
343 mark_bucket_linear = 1;
347 /* Try to add the new entry */
349 new_hash = BV (clib_bihash_hash) (add_v);
350 limit = BIHASH_KVP_PER_PAGE;
351 if (mark_bucket_linear)
352 limit <<= new_log2_pages;
353 new_hash >>= h->log2_nbuckets;
354 new_hash &= (1 << new_log2_pages) - 1;
355 new_v += mark_bucket_linear ? 0 : new_hash;
357 for (i = 0; i < limit; i++)
359 if (BV (clib_bihash_is_free) (&(new_v->kvp[i])))
361 clib_memcpy (&(new_v->kvp[i]), add_v, sizeof (*add_v));
365 /* Crap. Try again */
366 BV (value_free) (h, save_new_v);
368 * If we've already doubled the size of the bucket once,
369 * fall back to linear search now.
377 /* Keep track of the number of linear-scan buckets */
378 if (tmp_b.linear_search ^ mark_bucket_linear)
379 h->linear_buckets += (mark_bucket_linear == 1) ? 1 : -1;
381 tmp_b.log2_pages = new_log2_pages;
382 tmp_b.offset = BV (clib_bihash_get_offset) (h, save_new_v);
383 tmp_b.linear_search = mark_bucket_linear;
384 CLIB_MEMORY_BARRIER ();
385 b->as_u64 = tmp_b.as_u64;
386 v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
387 BV (value_free) (h, v);
390 CLIB_MEMORY_BARRIER ();
391 h->writer_lock[0] = 0;
395 int BV (clib_bihash_search)
396 (const BVT (clib_bihash) * h,
397 BVT (clib_bihash_kv) * search_key, BVT (clib_bihash_kv) * valuep)
401 BVT (clib_bihash_value) * v;
402 clib_bihash_bucket_t *b;
407 hash = BV (clib_bihash_hash) (search_key);
409 bucket_index = hash & (h->nbuckets - 1);
410 b = &h->buckets[bucket_index];
415 hash >>= h->log2_nbuckets;
417 v = BV (clib_bihash_get_value) (h, b->offset);
418 limit = BIHASH_KVP_PER_PAGE;
419 v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
420 if (PREDICT_FALSE (b->linear_search))
421 limit <<= b->log2_pages;
423 for (i = 0; i < limit; i++)
425 if (BV (clib_bihash_key_compare) (v->kvp[i].key, search_key->key))
434 u8 *BV (format_bihash) (u8 * s, va_list * args)
436 BVT (clib_bihash) * h = va_arg (*args, BVT (clib_bihash) *);
437 int verbose = va_arg (*args, int);
438 clib_bihash_bucket_t *b;
439 BVT (clib_bihash_value) * v;
441 u64 active_elements = 0;
443 s = format (s, "Hash table %s\n", h->name ? h->name : (u8 *) "(unnamed)");
445 for (i = 0; i < h->nbuckets; i++)
451 s = format (s, "[%d]: empty\n", i);
457 s = format (s, "[%d]: heap offset %d, len %d, linear %d\n", i,
458 b->offset, (1 << b->log2_pages), b->linear_search);
461 v = BV (clib_bihash_get_value) (h, b->offset);
462 for (j = 0; j < (1 << b->log2_pages); j++)
464 for (k = 0; k < BIHASH_KVP_PER_PAGE; k++)
466 if (BV (clib_bihash_is_free) (&v->kvp[k]))
469 s = format (s, " %d: empty\n",
470 j * BIHASH_KVP_PER_PAGE + k);
475 s = format (s, " %d: %U\n",
476 j * BIHASH_KVP_PER_PAGE + k,
477 BV (format_bihash_kvp), &(v->kvp[k]));
485 s = format (s, " %lld active elements\n", active_elements);
486 s = format (s, " %d free lists\n", vec_len (h->freelists));
487 s = format (s, " %d linear search buckets\n", h->linear_buckets);
492 void BV (clib_bihash_foreach_key_value_pair)
493 (BVT (clib_bihash) * h, void *callback, void *arg)
496 clib_bihash_bucket_t *b;
497 BVT (clib_bihash_value) * v;
498 void (*fp) (BVT (clib_bihash_kv) *, void *) = callback;
500 for (i = 0; i < h->nbuckets; i++)
506 v = BV (clib_bihash_get_value) (h, b->offset);
507 for (j = 0; j < (1 << b->log2_pages); j++)
509 for (k = 0; k < BIHASH_KVP_PER_PAGE; k++)
511 if (BV (clib_bihash_is_free) (&v->kvp[k]))
514 (*fp) (&v->kvp[k], arg);
524 * fd.io coding-style-patch-verification: ON
527 * eval: (c-set-style "gnu")