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)
24 nbuckets = 1 << (max_log2 (nbuckets));
26 h->name = (u8 *) name;
27 h->nbuckets = nbuckets;
28 h->log2_nbuckets = max_log2 (nbuckets);
32 h->mheap = mheap_alloc (0 /* use VM */ , memory_size);
34 oldheap = clib_mem_set_heap (h->mheap);
35 vec_validate_aligned (h->buckets, nbuckets - 1, CLIB_CACHE_LINE_BYTES);
36 h->writer_lock = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES,
37 CLIB_CACHE_LINE_BYTES);
38 h->writer_lock[0] = 0;
40 for (i = 0; i < nbuckets; i++)
41 BV (clib_bihash_reset_cache) (h->buckets + i);
43 clib_mem_set_heap (oldheap);
48 void BV (clib_bihash_set_kvp_format_fn) (BVT (clib_bihash) * h,
49 format_function_t * fmt_fn)
54 void BV (clib_bihash_free) (BVT (clib_bihash) * h)
56 mheap_free (h->mheap);
57 memset (h, 0, sizeof (*h));
61 BVT (clib_bihash_value) *
62 BV (value_alloc) (BVT (clib_bihash) * h, u32 log2_pages)
64 BVT (clib_bihash_value) * rv = 0;
67 ASSERT (h->writer_lock[0]);
68 if (log2_pages >= vec_len (h->freelists) || h->freelists[log2_pages] == 0)
70 oldheap = clib_mem_set_heap (h->mheap);
72 vec_validate (h->freelists, log2_pages);
73 rv = clib_mem_alloc_aligned ((sizeof (*rv) * (1 << log2_pages)),
74 CLIB_CACHE_LINE_BYTES);
75 clib_mem_set_heap (oldheap);
78 rv = h->freelists[log2_pages];
79 h->freelists[log2_pages] = rv->next_free;
84 * Latest gcc complains that the length arg is zero
85 * if we replace (1<<log2_pages) with vec_len(rv).
88 memset (rv, 0xff, sizeof (*rv) * (1 << log2_pages));
93 BV (value_free) (BVT (clib_bihash) * h, BVT (clib_bihash_value) * v,
96 ASSERT (h->writer_lock[0]);
98 ASSERT (vec_len (h->freelists) > log2_pages);
100 v->next_free = h->freelists[log2_pages];
101 h->freelists[log2_pages] = v;
105 BV (make_working_copy) (BVT (clib_bihash) * h, BVT (clib_bihash_bucket) * b)
107 BVT (clib_bihash_value) * v;
108 BVT (clib_bihash_bucket) working_bucket __attribute__ ((aligned (8)));
110 BVT (clib_bihash_value) * working_copy;
111 u32 thread_index = os_get_thread_index ();
112 int log2_working_copy_length;
114 if (thread_index >= vec_len (h->working_copies))
116 oldheap = clib_mem_set_heap (h->mheap);
117 vec_validate (h->working_copies, thread_index);
118 vec_validate_init_empty (h->working_copy_lengths, thread_index, ~0);
119 clib_mem_set_heap (oldheap);
123 * working_copies are per-cpu so that near-simultaneous
124 * updates from multiple threads will not result in sporadic, spurious
127 working_copy = h->working_copies[thread_index];
128 log2_working_copy_length = h->working_copy_lengths[thread_index];
130 h->saved_bucket.as_u64 = b->as_u64;
131 oldheap = clib_mem_set_heap (h->mheap);
133 if (b->log2_pages > log2_working_copy_length)
136 clib_mem_free (working_copy);
138 working_copy = clib_mem_alloc_aligned
139 (sizeof (working_copy[0]) * (1 << b->log2_pages),
140 CLIB_CACHE_LINE_BYTES);
141 h->working_copy_lengths[thread_index] = b->log2_pages;
142 h->working_copies[thread_index] = working_copy;
145 clib_mem_set_heap (oldheap);
147 /* Lock the bucket... */
148 while (BV (clib_bihash_lock_bucket) (b) == 0)
151 v = BV (clib_bihash_get_value) (h, b->offset);
153 clib_memcpy (working_copy, v, sizeof (*v) * (1 << b->log2_pages));
154 working_bucket.as_u64 = b->as_u64;
155 working_bucket.offset = BV (clib_bihash_get_offset) (h, working_copy);
156 CLIB_MEMORY_BARRIER ();
157 b->as_u64 = working_bucket.as_u64;
158 h->working_copies[thread_index] = working_copy;
162 BVT (clib_bihash_value) *
163 BV (split_and_rehash)
164 (BVT (clib_bihash) * h,
165 BVT (clib_bihash_value) * old_values, u32 old_log2_pages,
168 BVT (clib_bihash_value) * new_values, *new_v;
169 int i, j, length_in_kvs;
171 new_values = BV (value_alloc) (h, new_log2_pages);
172 length_in_kvs = (1 << old_log2_pages) * BIHASH_KVP_PER_PAGE;
174 for (i = 0; i < length_in_kvs; i++)
178 /* Entry not in use? Forget it */
179 if (BV (clib_bihash_is_free) (&(old_values->kvp[i])))
182 /* rehash the item onto its new home-page */
183 new_hash = BV (clib_bihash_hash) (&(old_values->kvp[i]));
184 new_hash >>= h->log2_nbuckets;
185 new_hash &= (1 << new_log2_pages) - 1;
186 new_v = &new_values[new_hash];
188 /* Across the new home-page */
189 for (j = 0; j < BIHASH_KVP_PER_PAGE; j++)
192 if (BV (clib_bihash_is_free) (&(new_v->kvp[j])))
194 clib_memcpy (&(new_v->kvp[j]), &(old_values->kvp[i]),
195 sizeof (new_v->kvp[j]));
199 /* Crap. Tell caller to try again */
200 BV (value_free) (h, new_values, new_log2_pages);
209 BVT (clib_bihash_value) *
210 BV (split_and_rehash_linear)
211 (BVT (clib_bihash) * h,
212 BVT (clib_bihash_value) * old_values, u32 old_log2_pages,
215 BVT (clib_bihash_value) * new_values;
216 int i, j, new_length, old_length;
218 new_values = BV (value_alloc) (h, new_log2_pages);
219 new_length = (1 << new_log2_pages) * BIHASH_KVP_PER_PAGE;
220 old_length = (1 << old_log2_pages) * BIHASH_KVP_PER_PAGE;
223 /* Across the old value array */
224 for (i = 0; i < old_length; i++)
226 /* Find a free slot in the new linear scan bucket */
227 for (; j < new_length; j++)
229 /* Old value not in use? Forget it. */
230 if (BV (clib_bihash_is_free) (&(old_values->kvp[i])))
233 /* New value should never be in use */
234 if (BV (clib_bihash_is_free) (&(new_values->kvp[j])))
236 /* Copy the old value and move along */
237 clib_memcpy (&(new_values->kvp[j]), &(old_values->kvp[i]),
238 sizeof (new_values->kvp[j]));
243 /* This should never happen... */
244 clib_warning ("BUG: linear rehash failed!");
245 BV (value_free) (h, new_values, new_log2_pages);
253 int BV (clib_bihash_add_del)
254 (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add)
257 BVT (clib_bihash_bucket) * b, tmp_b;
258 BVT (clib_bihash_value) * v, *new_v, *save_new_v, *working_copy;
262 u32 new_log2_pages, old_log2_pages;
263 u32 thread_index = os_get_thread_index ();
264 int mark_bucket_linear;
267 hash = BV (clib_bihash_hash) (add_v);
269 bucket_index = hash & (h->nbuckets - 1);
270 b = &h->buckets[bucket_index];
272 hash >>= h->log2_nbuckets;
274 tmp_b.linear_search = 0;
276 while (__sync_lock_test_and_set (h->writer_lock, 1))
279 /* First elt in the bucket? */
288 v = BV (value_alloc) (h, 0);
292 tmp_b.offset = BV (clib_bihash_get_offset) (h, v);
294 b->as_u64 = tmp_b.as_u64;
298 /* Note: this leaves the cache disabled */
299 BV (make_working_copy) (h, b);
301 v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
303 limit = BIHASH_KVP_PER_PAGE;
304 v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
305 if (b->linear_search)
306 limit <<= b->log2_pages;
311 * For obvious (in hindsight) reasons, see if we're supposed to
312 * replace an existing key, then look for an empty slot.
314 for (i = 0; i < limit; i++)
316 if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
318 clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
319 CLIB_MEMORY_BARRIER ();
320 /* Restore the previous (k,v) pairs */
321 b->as_u64 = h->saved_bucket.as_u64;
325 for (i = 0; i < limit; i++)
327 if (BV (clib_bihash_is_free) (&(v->kvp[i])))
329 clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
330 CLIB_MEMORY_BARRIER ();
331 b->as_u64 = h->saved_bucket.as_u64;
335 /* no room at the inn... split case... */
339 for (i = 0; i < limit; i++)
341 if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
343 memset (&(v->kvp[i]), 0xff, sizeof (*(add_v)));
344 CLIB_MEMORY_BARRIER ();
345 b->as_u64 = h->saved_bucket.as_u64;
350 b->as_u64 = h->saved_bucket.as_u64;
354 old_log2_pages = h->saved_bucket.log2_pages;
355 new_log2_pages = old_log2_pages + 1;
356 mark_bucket_linear = 0;
358 working_copy = h->working_copies[thread_index];
361 new_v = BV (split_and_rehash) (h, working_copy, old_log2_pages,
368 /* Try re-splitting. If that fails, fall back to linear search */
369 new_v = BV (split_and_rehash) (h, working_copy, old_log2_pages,
375 /* pinned collisions, use linear search */
377 BV (split_and_rehash_linear) (h, working_copy, old_log2_pages,
379 mark_bucket_linear = 1;
383 /* Try to add the new entry */
385 new_hash = BV (clib_bihash_hash) (add_v);
386 limit = BIHASH_KVP_PER_PAGE;
387 if (mark_bucket_linear)
388 limit <<= new_log2_pages;
389 new_hash >>= h->log2_nbuckets;
390 new_hash &= (1 << new_log2_pages) - 1;
391 new_v += mark_bucket_linear ? 0 : new_hash;
393 for (i = 0; i < limit; i++)
395 if (BV (clib_bihash_is_free) (&(new_v->kvp[i])))
397 clib_memcpy (&(new_v->kvp[i]), add_v, sizeof (*add_v));
402 /* Crap. Try again */
403 BV (value_free) (h, save_new_v, new_log2_pages);
405 * If we've already doubled the size of the bucket once,
406 * fall back to linear search now.
414 /* Keep track of the number of linear-scan buckets */
415 if (tmp_b.linear_search ^ mark_bucket_linear)
416 h->linear_buckets += (mark_bucket_linear == 1) ? 1 : -1;
418 tmp_b.log2_pages = new_log2_pages;
419 tmp_b.offset = BV (clib_bihash_get_offset) (h, save_new_v);
420 tmp_b.linear_search = mark_bucket_linear;
422 CLIB_MEMORY_BARRIER ();
423 b->as_u64 = tmp_b.as_u64;
424 v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
425 BV (value_free) (h, v, old_log2_pages);
428 BV (clib_bihash_reset_cache) (b);
429 BV (clib_bihash_unlock_bucket) (b);
430 CLIB_MEMORY_BARRIER ();
431 h->writer_lock[0] = 0;
435 int BV (clib_bihash_search)
436 (BVT (clib_bihash) * h,
437 BVT (clib_bihash_kv) * search_key, BVT (clib_bihash_kv) * valuep)
441 BVT (clib_bihash_value) * v;
442 #if BIHASH_KVP_CACHE_SIZE > 0
443 BVT (clib_bihash_kv) * kvp;
445 BVT (clib_bihash_bucket) * b;
450 hash = BV (clib_bihash_hash) (search_key);
452 bucket_index = hash & (h->nbuckets - 1);
453 b = &h->buckets[bucket_index];
458 #if BIHASH_KVP_CACHE_SIZE > 0
459 /* Check the cache, if currently enabled */
460 if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
462 limit = BIHASH_KVP_CACHE_SIZE;
464 for (i = 0; i < limit; i++)
466 if (BV (clib_bihash_key_compare) (kvp[i].key, search_key->key))
476 hash >>= h->log2_nbuckets;
478 v = BV (clib_bihash_get_value) (h, b->offset);
479 limit = BIHASH_KVP_PER_PAGE;
480 v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
481 if (PREDICT_FALSE (b->linear_search))
482 limit <<= b->log2_pages;
484 for (i = 0; i < limit; i++)
486 if (BV (clib_bihash_key_compare) (v->kvp[i].key, search_key->key))
490 #if BIHASH_KVP_CACHE_SIZE > 0
492 /* Shut off the cache */
493 if (BV (clib_bihash_lock_bucket) (b))
495 cache_slot = BV (clib_bihash_get_lru) (b);
496 b->cache[cache_slot] = v->kvp[i];
497 BV (clib_bihash_update_lru) (b, cache_slot);
499 /* Reenable the cache */
500 BV (clib_bihash_unlock_bucket) (b);
510 u8 *BV (format_bihash_lru) (u8 * s, va_list * args)
512 #if BIHASH_KVP_SIZE > 0
514 BVT (clib_bihash_bucket) * b = va_arg (*args, BVT (clib_bihash_bucket) *);
515 u16 cache_lru = b->cache_lru;
517 s = format (s, "cache %s, order ", cache_lru & (1 << 15) ? "on" : "off");
519 for (i = 0; i < BIHASH_KVP_CACHE_SIZE; i++)
520 s = format (s, "[%d] ", ((cache_lru >> (3 * i)) & 7));
524 return format (s, "cache not configured");
529 BV (clib_bihash_update_lru_not_inline) (BVT (clib_bihash_bucket) * b, u8 slot)
531 #if BIHASH_KVP_SIZE > 0
532 BV (clib_bihash_update_lru) (b, slot);
536 u8 *BV (format_bihash) (u8 * s, va_list * args)
538 BVT (clib_bihash) * h = va_arg (*args, BVT (clib_bihash) *);
539 int verbose = va_arg (*args, int);
540 BVT (clib_bihash_bucket) * b;
541 BVT (clib_bihash_value) * v;
543 u64 active_elements = 0;
545 s = format (s, "Hash table %s\n", h->name ? h->name : (u8 *) "(unnamed)");
547 for (i = 0; i < h->nbuckets; i++)
553 s = format (s, "[%d]: empty\n", i);
559 s = format (s, "[%d]: heap offset %d, len %d, linear %d\n", i,
560 b->offset, (1 << b->log2_pages), b->linear_search);
563 v = BV (clib_bihash_get_value) (h, b->offset);
564 for (j = 0; j < (1 << b->log2_pages); j++)
566 for (k = 0; k < BIHASH_KVP_PER_PAGE; k++)
568 if (BV (clib_bihash_is_free) (&v->kvp[k]))
571 s = format (s, " %d: empty\n",
572 j * BIHASH_KVP_PER_PAGE + k);
579 s = format (s, " %d: %U\n",
580 j * BIHASH_KVP_PER_PAGE + k,
581 h->fmt_fn, &(v->kvp[k]));
585 s = format (s, " %d: %U\n",
586 j * BIHASH_KVP_PER_PAGE + k,
587 BV (format_bihash_kvp), &(v->kvp[k]));
596 s = format (s, " %lld active elements\n", active_elements);
597 s = format (s, " %d free lists\n", vec_len (h->freelists));
598 s = format (s, " %d linear search buckets\n", h->linear_buckets);
599 s = format (s, " %lld cache hits, %lld cache misses\n",
600 h->cache_hits, h->cache_misses);
604 void BV (clib_bihash_foreach_key_value_pair)
605 (BVT (clib_bihash) * h, void *callback, void *arg)
608 BVT (clib_bihash_bucket) * b;
609 BVT (clib_bihash_value) * v;
610 void (*fp) (BVT (clib_bihash_kv) *, void *) = callback;
612 for (i = 0; i < h->nbuckets; i++)
618 v = BV (clib_bihash_get_value) (h, b->offset);
619 for (j = 0; j < (1 << b->log2_pages); j++)
621 for (k = 0; k < BIHASH_KVP_PER_PAGE; k++)
623 if (BV (clib_bihash_is_free) (&v->kvp[k]))
626 (*fp) (&v->kvp[k], arg);
636 * fd.io coding-style-patch-verification: ON
639 * eval: (c-set-style "gnu")