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 not 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]));
216 /* This should never happen... */
217 clib_warning ("BUG: linear rehash failed!");
218 BV (value_free) (h, new_values);
226 int BV (clib_bihash_add_del)
227 (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add)
230 clib_bihash_bucket_t *b, tmp_b;
231 BVT (clib_bihash_value) * v, *new_v, *save_new_v, *working_copy;
236 u32 cpu_number = os_get_cpu_number ();
237 int mark_bucket_linear;
240 hash = BV (clib_bihash_hash) (add_v);
242 bucket_index = hash & (h->nbuckets - 1);
243 b = &h->buckets[bucket_index];
245 hash >>= h->log2_nbuckets;
247 while (__sync_lock_test_and_set (h->writer_lock, 1))
250 /* First elt in the bucket? */
259 v = BV (value_alloc) (h, 0);
262 tmp_b.offset = BV (clib_bihash_get_offset) (h, v);
264 b->as_u64 = tmp_b.as_u64;
268 BV (make_working_copy) (h, b);
270 v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
272 limit = BIHASH_KVP_PER_PAGE;
273 v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
274 if (b->linear_search)
275 limit <<= b->log2_pages;
280 * For obvious (in hindsight) reasons, see if we're supposed to
281 * replace an existing key, then look for an empty slot.
283 for (i = 0; i < limit; i++)
285 if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
287 clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
288 CLIB_MEMORY_BARRIER ();
289 /* Restore the previous (k,v) pairs */
290 b->as_u64 = h->saved_bucket.as_u64;
294 for (i = 0; i < limit; i++)
296 if (BV (clib_bihash_is_free) (&(v->kvp[i])))
298 clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
299 CLIB_MEMORY_BARRIER ();
300 b->as_u64 = h->saved_bucket.as_u64;
304 /* no room at the inn... split case... */
308 for (i = 0; i < limit; i++)
310 if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
312 memset (&(v->kvp[i]), 0xff, sizeof (*(add_v)));
313 CLIB_MEMORY_BARRIER ();
314 b->as_u64 = h->saved_bucket.as_u64;
319 b->as_u64 = h->saved_bucket.as_u64;
323 new_log2_pages = h->saved_bucket.log2_pages + 1;
324 mark_bucket_linear = 0;
326 working_copy = h->working_copies[cpu_number];
329 new_v = BV (split_and_rehash) (h, working_copy, new_log2_pages);
335 /* Try re-splitting. If that fails, fall back to linear search */
336 new_v = BV (split_and_rehash) (h, working_copy, new_log2_pages);
341 /* pinned collisions, use linear search */
343 BV (split_and_rehash_linear) (h, working_copy, new_log2_pages);
344 mark_bucket_linear = 1;
348 /* Try to add the new entry */
350 new_hash = BV (clib_bihash_hash) (add_v);
351 limit = BIHASH_KVP_PER_PAGE;
352 if (mark_bucket_linear)
353 limit <<= new_log2_pages;
354 new_hash >>= h->log2_nbuckets;
355 new_hash &= (1 << new_log2_pages) - 1;
356 new_v += mark_bucket_linear ? 0 : new_hash;
358 for (i = 0; i < limit; i++)
360 if (BV (clib_bihash_is_free) (&(new_v->kvp[i])))
362 clib_memcpy (&(new_v->kvp[i]), add_v, sizeof (*add_v));
366 /* Crap. Try again */
367 BV (value_free) (h, save_new_v);
369 * If we've already doubled the size of the bucket once,
370 * fall back to linear search now.
378 /* Keep track of the number of linear-scan buckets */
379 if (tmp_b.linear_search ^ mark_bucket_linear)
380 h->linear_buckets += (mark_bucket_linear == 1) ? 1 : -1;
382 tmp_b.log2_pages = new_log2_pages;
383 tmp_b.offset = BV (clib_bihash_get_offset) (h, save_new_v);
384 tmp_b.linear_search = mark_bucket_linear;
385 CLIB_MEMORY_BARRIER ();
386 b->as_u64 = tmp_b.as_u64;
387 v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
388 BV (value_free) (h, v);
391 CLIB_MEMORY_BARRIER ();
392 h->writer_lock[0] = 0;
396 int BV (clib_bihash_search)
397 (const BVT (clib_bihash) * h,
398 BVT (clib_bihash_kv) * search_key, BVT (clib_bihash_kv) * valuep)
402 BVT (clib_bihash_value) * v;
403 clib_bihash_bucket_t *b;
408 hash = BV (clib_bihash_hash) (search_key);
410 bucket_index = hash & (h->nbuckets - 1);
411 b = &h->buckets[bucket_index];
416 hash >>= h->log2_nbuckets;
418 v = BV (clib_bihash_get_value) (h, b->offset);
419 limit = BIHASH_KVP_PER_PAGE;
420 v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
421 if (PREDICT_FALSE (b->linear_search))
422 limit <<= b->log2_pages;
424 for (i = 0; i < limit; i++)
426 if (BV (clib_bihash_key_compare) (v->kvp[i].key, search_key->key))
435 u8 *BV (format_bihash) (u8 * s, va_list * args)
437 BVT (clib_bihash) * h = va_arg (*args, BVT (clib_bihash) *);
438 int verbose = va_arg (*args, int);
439 clib_bihash_bucket_t *b;
440 BVT (clib_bihash_value) * v;
442 u64 active_elements = 0;
444 s = format (s, "Hash table %s\n", h->name ? h->name : (u8 *) "(unnamed)");
446 for (i = 0; i < h->nbuckets; i++)
452 s = format (s, "[%d]: empty\n", i);
458 s = format (s, "[%d]: heap offset %d, len %d, linear %d\n", i,
459 b->offset, (1 << b->log2_pages), b->linear_search);
462 v = BV (clib_bihash_get_value) (h, b->offset);
463 for (j = 0; j < (1 << b->log2_pages); j++)
465 for (k = 0; k < BIHASH_KVP_PER_PAGE; k++)
467 if (BV (clib_bihash_is_free) (&v->kvp[k]))
470 s = format (s, " %d: empty\n",
471 j * BIHASH_KVP_PER_PAGE + k);
476 s = format (s, " %d: %U\n",
477 j * BIHASH_KVP_PER_PAGE + k,
478 BV (format_bihash_kvp), &(v->kvp[k]));
486 s = format (s, " %lld active elements\n", active_elements);
487 s = format (s, " %d free lists\n", vec_len (h->freelists));
488 s = format (s, " %d linear search buckets\n", h->linear_buckets);
493 void BV (clib_bihash_foreach_key_value_pair)
494 (BVT (clib_bihash) * h, void *callback, void *arg)
497 clib_bihash_bucket_t *b;
498 BVT (clib_bihash_value) * v;
499 void (*fp) (BVT (clib_bihash_kv) *, void *) = callback;
501 for (i = 0; i < h->nbuckets; i++)
507 v = BV (clib_bihash_get_value) (h, b->offset);
508 for (j = 0; j < (1 << b->log2_pages); j++)
510 for (k = 0; k < BIHASH_KVP_PER_PAGE; k++)
512 if (BV (clib_bihash_is_free) (&v->kvp[k]))
515 (*fp) (&v->kvp[k], arg);
525 * fd.io coding-style-patch-verification: ON
528 * eval: (c-set-style "gnu")