FD.io VPP  v17.10-9-gd594711
Vector Packet Processing
bihash_template.h
Go to the documentation of this file.
1 /*
2  Copyright (c) 2014 Cisco and/or its affiliates.
3 
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at:
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15 */
16 
17 /** @cond DOCUMENTATION_IS_IN_BIHASH_DOC_H */
18 
19 /*
20  * Note: to instantiate the template multiple times in a single file,
21  * #undef __included_bihash_template_h__...
22  */
23 #ifndef __included_bihash_template_h__
24 #define __included_bihash_template_h__
25 
26 #include <vppinfra/heap.h>
27 #include <vppinfra/format.h>
28 #include <vppinfra/pool.h>
29 
30 #ifndef BIHASH_TYPE
31 #error BIHASH_TYPE not defined
32 #endif
33 
34 #define _bv(a,b) a##b
35 #define __bv(a,b) _bv(a,b)
36 #define BV(a) __bv(a,BIHASH_TYPE)
37 
38 #define _bvt(a,b) a##b##_t
39 #define __bvt(a,b) _bvt(a,b)
40 #define BVT(a) __bvt(a,BIHASH_TYPE)
41 
42 typedef struct BV (clib_bihash_value)
43 {
44  union
45  {
46  BVT (clib_bihash_kv) kvp[BIHASH_KVP_PER_PAGE];
47  struct BV (clib_bihash_value) * next_free;
48  };
49 } BVT (clib_bihash_value);
50 
51 #if BIHASH_KVP_CACHE_SIZE > 5
52 #error Requested KVP cache LRU data exceeds 16 bits
53 #endif
54 
55 typedef struct
56 {
57  union
58  {
59  struct
60  {
61  u32 offset;
62  u8 linear_search;
63  u8 log2_pages;
64  u16 cache_lru;
65  };
66  u64 as_u64;
67  };
68 #if BIHASH_KVP_CACHE_SIZE > 0
69  BVT (clib_bihash_kv) cache[BIHASH_KVP_CACHE_SIZE];
70 #endif
71 } BVT (clib_bihash_bucket);
72 
73 typedef struct
74 {
75  BVT (clib_bihash_value) * values;
76  BVT (clib_bihash_bucket) * buckets;
77  volatile u32 *writer_lock;
78 
79  BVT (clib_bihash_value) ** working_copies;
80  int *working_copy_lengths;
81  BVT (clib_bihash_bucket) saved_bucket;
82 
83  u32 nbuckets;
84  u32 log2_nbuckets;
85  u32 linear_buckets;
86  u8 *name;
87 
88  u64 cache_hits;
89  u64 cache_misses;
90 
91  BVT (clib_bihash_value) ** freelists;
92  void *mheap;
93 
94 } BVT (clib_bihash);
95 
96 
97 static inline void
98 BV (clib_bihash_update_lru) (BVT (clib_bihash_bucket) * b, u8 slot)
99 {
100  u16 value, tmp, mask;
101  u8 found_lru_pos;
102  u16 save_hi;
103 
104  if (BIHASH_KVP_CACHE_SIZE < 2)
105  return;
106 
107  ASSERT (slot < BIHASH_KVP_CACHE_SIZE);
108 
109  /* First, find the slot in cache_lru */
110  mask = slot;
111  if (BIHASH_KVP_CACHE_SIZE > 1)
112  mask |= slot << 3;
113  if (BIHASH_KVP_CACHE_SIZE > 2)
114  mask |= slot << 6;
115  if (BIHASH_KVP_CACHE_SIZE > 3)
116  mask |= slot << 9;
117  if (BIHASH_KVP_CACHE_SIZE > 4)
118  mask |= slot << 12;
119 
120  value = b->cache_lru;
121  tmp = value ^ mask;
122 
123  /* Already the most-recently used? */
124  if ((tmp & 7) == 0)
125  return;
126 
127  found_lru_pos = ((tmp & (7 << 3)) == 0) ? 1 : 0;
128  if (BIHASH_KVP_CACHE_SIZE > 2)
129  found_lru_pos = ((tmp & (7 << 6)) == 0) ? 2 : found_lru_pos;
130  if (BIHASH_KVP_CACHE_SIZE > 3)
131  found_lru_pos = ((tmp & (7 << 9)) == 0) ? 3 : found_lru_pos;
132  if (BIHASH_KVP_CACHE_SIZE > 4)
133  found_lru_pos = ((tmp & (7 << 12)) == 0) ? 4 : found_lru_pos;
134 
135  ASSERT (found_lru_pos);
136 
137  /* create a mask to kill bits in or above slot */
138  mask = 0xFFFF << found_lru_pos;
139  mask <<= found_lru_pos;
140  mask <<= found_lru_pos;
141  mask ^= 0xFFFF;
142  tmp = value & mask;
143 
144  /* Save bits above slot */
145  mask ^= 0xFFFF;
146  mask <<= 3;
147  save_hi = value & mask;
148 
149  value = save_hi | (tmp << 3) | slot;
150 
151  b->cache_lru = value;
152 }
153 
154 void
155 BV (clib_bihash_update_lru_not_inline) (BVT (clib_bihash_bucket) * b,
156  u8 slot);
157 
158 static inline u8 BV (clib_bihash_get_lru) (BVT (clib_bihash_bucket) * b)
159 {
160 #if BIHASH_KVP_CACHE_SIZE > 0
161  return (b->cache_lru >> (3 * (BIHASH_KVP_CACHE_SIZE - 1))) & 7;
162 #else
163  return 0;
164 #endif
165 }
166 
167 static inline void BV (clib_bihash_reset_cache) (BVT (clib_bihash_bucket) * b)
168 {
169 #if BIHASH_KVP_CACHE_SIZE > 0
170  u16 initial_lru_value;
171 
172  memset (b->cache, 0xff, sizeof (b->cache));
173 
174  /*
175  * We'll want the cache to be loaded from slot 0 -> slot N, so
176  * the initial LRU order is reverse index order.
177  */
178  if (BIHASH_KVP_CACHE_SIZE == 1)
179  initial_lru_value = 0;
180  else if (BIHASH_KVP_CACHE_SIZE == 2)
181  initial_lru_value = (0 << 3) | (1 << 0);
182  else if (BIHASH_KVP_CACHE_SIZE == 3)
183  initial_lru_value = (0 << 6) | (1 << 3) | (2 << 0);
184  else if (BIHASH_KVP_CACHE_SIZE == 4)
185  initial_lru_value = (0 << 9) | (1 << 6) | (2 << 3) | (3 << 0);
186  else if (BIHASH_KVP_CACHE_SIZE == 5)
187  initial_lru_value = (0 << 12) | (1 << 9) | (2 << 6) | (3 << 3) | (4 << 0);
188 
189  b->cache_lru = initial_lru_value;
190 #endif
191 }
192 
193 static inline int BV (clib_bihash_lock_bucket) (BVT (clib_bihash_bucket) * b)
194 {
195  BVT (clib_bihash_bucket) tmp_b;
196  u64 rv;
197 
198  tmp_b.as_u64 = 0;
199  tmp_b.cache_lru = 1 << 15;
200 
201  rv = __sync_fetch_and_or (&b->as_u64, tmp_b.as_u64);
202  tmp_b.as_u64 = rv;
203  /* Was already locked? */
204  if (tmp_b.cache_lru & (1 << 15))
205  return 0;
206  return 1;
207 }
208 
209 static inline void BV (clib_bihash_unlock_bucket)
210  (BVT (clib_bihash_bucket) * b)
211 {
212  BVT (clib_bihash_bucket) tmp_b;
213 
214  tmp_b.as_u64 = b->as_u64;
215  tmp_b.cache_lru &= ~(1 << 15);
216  b->as_u64 = tmp_b.as_u64;
217 }
218 
219 static inline void *BV (clib_bihash_get_value) (BVT (clib_bihash) * h,
220  uword offset)
221 {
222  u8 *hp = h->mheap;
223  u8 *vp = hp + offset;
224 
225  return (void *) vp;
226 }
227 
228 static inline uword BV (clib_bihash_get_offset) (BVT (clib_bihash) * h,
229  void *v)
230 {
231  u8 *hp, *vp;
232 
233  hp = (u8 *) h->mheap;
234  vp = (u8 *) v;
235 
236  ASSERT ((vp - hp) < 0x100000000ULL);
237  return vp - hp;
238 }
239 
240 void BV (clib_bihash_init)
241  (BVT (clib_bihash) * h, char *name, u32 nbuckets, uword memory_size);
242 
243 void BV (clib_bihash_free) (BVT (clib_bihash) * h);
244 
245 int BV (clib_bihash_add_del) (BVT (clib_bihash) * h,
246  BVT (clib_bihash_kv) * add_v, int is_add);
247 int BV (clib_bihash_search) (BVT (clib_bihash) * h,
248  BVT (clib_bihash_kv) * search_v,
249  BVT (clib_bihash_kv) * return_v);
250 
251 void BV (clib_bihash_foreach_key_value_pair) (BVT (clib_bihash) * h,
252  void *callback, void *arg);
253 
254 format_function_t BV (format_bihash);
255 format_function_t BV (format_bihash_kvp);
256 format_function_t BV (format_bihash_lru);
257 
258 static inline int BV (clib_bihash_search_inline)
259  (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * key_result)
260 {
261  u64 hash;
262  u32 bucket_index;
263  BVT (clib_bihash_value) * v;
264  BVT (clib_bihash_bucket) * b;
265 #if BIHASH_KVP_CACHE_SIZE > 0
266  BVT (clib_bihash_kv) * kvp;
267 #endif
268  int i, limit;
269 
270  hash = BV (clib_bihash_hash) (key_result);
271 
272  bucket_index = hash & (h->nbuckets - 1);
273  b = &h->buckets[bucket_index];
274 
275  if (b->offset == 0)
276  return -1;
277 
278 #if BIHASH_KVP_CACHE_SIZE > 0
279  /* Check the cache, if not currently locked */
280  if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
281  {
282  limit = BIHASH_KVP_CACHE_SIZE;
283  kvp = b->cache;
284  for (i = 0; i < limit; i++)
285  {
286  if (BV (clib_bihash_key_compare) (kvp[i].key, key_result->key))
287  {
288  *key_result = kvp[i];
289  h->cache_hits++;
290  return 0;
291  }
292  }
293  }
294 #endif
295 
296  hash >>= h->log2_nbuckets;
297 
298  v = BV (clib_bihash_get_value) (h, b->offset);
299 
300  /* If the bucket has unresolvable collisions, use linear search */
301  limit = BIHASH_KVP_PER_PAGE;
302  v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
303  if (PREDICT_FALSE (b->linear_search))
304  limit <<= b->log2_pages;
305 
306  for (i = 0; i < limit; i++)
307  {
308  if (BV (clib_bihash_key_compare) (v->kvp[i].key, key_result->key))
309  {
310  *key_result = v->kvp[i];
311 
312 #if BIHASH_KVP_CACHE_SIZE > 0
313  u8 cache_slot;
314  /* Try to lock the bucket */
315  if (BV (clib_bihash_lock_bucket) (b))
316  {
317  cache_slot = BV (clib_bihash_get_lru) (b);
318  b->cache[cache_slot] = v->kvp[i];
319  BV (clib_bihash_update_lru) (b, cache_slot);
320 
321  /* Unlock the bucket */
322  BV (clib_bihash_unlock_bucket) (b);
323  h->cache_misses++;
324  }
325 #endif
326  return 0;
327  }
328  }
329  return -1;
330 }
331 
332 static inline int BV (clib_bihash_search_inline_2)
333  (BVT (clib_bihash) * h,
334  BVT (clib_bihash_kv) * search_key, BVT (clib_bihash_kv) * valuep)
335 {
336  u64 hash;
337  u32 bucket_index;
338  BVT (clib_bihash_value) * v;
339  BVT (clib_bihash_bucket) * b;
340 #if BIHASH_KVP_CACHE_SIZE > 0
341  BVT (clib_bihash_kv) * kvp;
342 #endif
343  int i, limit;
344 
345  ASSERT (valuep);
346 
347  hash = BV (clib_bihash_hash) (search_key);
348 
349  bucket_index = hash & (h->nbuckets - 1);
350  b = &h->buckets[bucket_index];
351 
352  if (b->offset == 0)
353  return -1;
354 
355  /* Check the cache, if currently unlocked */
356 #if BIHASH_KVP_CACHE_SIZE > 0
357  if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
358  {
359  limit = BIHASH_KVP_CACHE_SIZE;
360  kvp = b->cache;
361  for (i = 0; i < limit; i++)
362  {
363  if (BV (clib_bihash_key_compare) (kvp[i].key, search_key->key))
364  {
365  *valuep = kvp[i];
366  h->cache_hits++;
367  return 0;
368  }
369  }
370  }
371 #endif
372 
373  hash >>= h->log2_nbuckets;
374  v = BV (clib_bihash_get_value) (h, b->offset);
375 
376  /* If the bucket has unresolvable collisions, use linear search */
377  limit = BIHASH_KVP_PER_PAGE;
378  v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
379  if (PREDICT_FALSE (b->linear_search))
380  limit <<= b->log2_pages;
381 
382  for (i = 0; i < limit; i++)
383  {
384  if (BV (clib_bihash_key_compare) (v->kvp[i].key, search_key->key))
385  {
386  *valuep = v->kvp[i];
387 
388 #if BIHASH_KVP_CACHE_SIZE > 0
389  u8 cache_slot;
390 
391  /* Try to lock the bucket */
392  if (BV (clib_bihash_lock_bucket) (b))
393  {
394  cache_slot = BV (clib_bihash_get_lru) (b);
395  b->cache[cache_slot] = v->kvp[i];
396  BV (clib_bihash_update_lru) (b, cache_slot);
397 
398  /* Reenable the cache */
399  BV (clib_bihash_unlock_bucket) (b);
400  h->cache_misses++;
401  }
402 #endif
403  return 0;
404  }
405  }
406  return -1;
407 }
408 
409 #endif /* __included_bihash_template_h__ */
410 
411 /** @endcond */
412 
413 /*
414  * fd.io coding-style-patch-verification: ON
415  *
416  * Local Variables:
417  * eval: (c-set-style "gnu")
418  * End:
419  */
sll srl srl sll sra u16x4 i
Definition: vector_sse2.h:337
#define BIHASH_KVP_PER_PAGE
Definition: bihash_16_8.h:20
u64 as_u64
Definition: bihash_doc.h:63
void clib_bihash_free(clib_bihash *h)
Destroy a bounded index extensible hash table.
#define PREDICT_TRUE(x)
Definition: clib.h:98
Fixed length block allocator.
u8 *( format_function_t)(u8 *s, va_list *args)
Definition: format.h:48
int clib_bihash_add_del(clib_bihash *h, clib_bihash_kv *add_v, int is_add)
Add or delete a (key,value) pair from a bi-hash table.
static BVT(clib_bihash)
Definition: adj_nbr.c:26
unsigned long u64
Definition: types.h:89
static uword clib_bihash_get_offset(clib_bihash *h, void *v)
Get clib mheap offset given a pointer.
#define v
Definition: acl.c:323
#define PREDICT_FALSE(x)
Definition: clib.h:97
void clib_bihash_init(clib_bihash *h, char *name, u32 nbuckets, uword memory_size)
initialize a bounded index extensible hash table
void clib_bihash_foreach_key_value_pair(clib_bihash *h, void *callback, void *arg)
Visit active (key,value) pairs in a bi-hash table.
vec_header_t h
Definition: buffer.c:282
u64 memory_size
Definition: vhost-user.h:77
#define ASSERT(truth)
unsigned int u32
Definition: types.h:88
int clib_bihash_search(clib_bihash *h, clib_bihash_kv *search_v, clib_bihash_kv *return_v)
Search a bi-hash table.
u8 log2_pages
Definition: bihash_doc.h:62
u64 uword
Definition: types.h:112
unsigned short u16
Definition: types.h:57
unsigned char u8
Definition: types.h:56
struct clib_bihash_value offset
template key/value backing page structure
static void * clib_bihash_get_value(clib_bihash *h, uword offset)
Get pointer to value page given its clib mheap offset.
#define BIHASH_KVP_CACHE_SIZE
Definition: bihash_16_8.h:21