1 /*
2 * GPL HEADER START
3 *
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
19 *
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
22 * have any questions.
23 *
24 * GPL HEADER END
25 */
26 /*
27 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
29 *
30 * Copyright (c) 2012, Intel Corporation.
31 */
32 /*
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
35 *
36 * libcfs/include/libcfs/libcfs_hash.h
37 *
38 * Hashing routines
39 *
40 */
41
42 #ifndef __LIBCFS_HASH_H__
43 #define __LIBCFS_HASH_H__
44 /*
45 * Knuth recommends primes in approximately golden ratio to the maximum
46 * integer representable by a machine word for multiplicative hashing.
47 * Chuck Lever verified the effectiveness of this technique:
48 * http://www.citi.umich.edu/techreports/reports/citi-tr-00-1.pdf
49 *
50 * These primes are chosen to be bit-sparse, that is operations on
51 * them can use shifts and additions instead of multiplications for
52 * machines where multiplications are slow.
53 */
54 /* 2^31 + 2^29 - 2^25 + 2^22 - 2^19 - 2^16 + 1 */
55 #define CFS_GOLDEN_RATIO_PRIME_32 0x9e370001UL
56 /* 2^63 + 2^61 - 2^57 + 2^54 - 2^51 - 2^18 + 1 */
57 #define CFS_GOLDEN_RATIO_PRIME_64 0x9e37fffffffc0001ULL
58
59 /*
60 * Ideally we would use HAVE_HASH_LONG for this, but on linux we configure
61 * the linux kernel and user space at the same time, so we need to differentiate
62 * between them explicitly. If this is not needed on other architectures, then
63 * we'll need to move the functions to architecture specific headers.
64 */
65
66 #include <linux/hash.h>
67
68 /** disable debug */
69 #define CFS_HASH_DEBUG_NONE 0
70 /** record hash depth and output to console when it's too deep,
71 * computing overhead is low but consume more memory */
72 #define CFS_HASH_DEBUG_1 1
73 /** expensive, check key validation */
74 #define CFS_HASH_DEBUG_2 2
75
76 #define CFS_HASH_DEBUG_LEVEL CFS_HASH_DEBUG_NONE
77
78 struct cfs_hash_ops;
79 struct cfs_hash_lock_ops;
80 struct cfs_hash_hlist_ops;
81
82 union cfs_hash_lock {
83 rwlock_t rw; /**< rwlock */
84 spinlock_t spin; /**< spinlock */
85 };
86
87 /**
88 * cfs_hash_bucket is a container of:
89 * - lock, counter ...
90 * - array of hash-head starting from hsb_head[0], hash-head can be one of
91 * . struct cfs_hash_head
92 * . struct cfs_hash_head_dep
93 * . struct cfs_hash_dhead
94 * . struct cfs_hash_dhead_dep
95 * which depends on requirement of user
96 * - some extra bytes (caller can require it while creating hash)
97 */
98 struct cfs_hash_bucket {
99 union cfs_hash_lock hsb_lock; /**< bucket lock */
100 __u32 hsb_count; /**< current entries */
101 __u32 hsb_version; /**< change version */
102 unsigned int hsb_index; /**< index of bucket */
103 int hsb_depmax; /**< max depth on bucket */
104 long hsb_head[0]; /**< hash-head array */
105 };
106
107 /**
108 * cfs_hash bucket descriptor, it's normally in stack of caller
109 */
110 struct cfs_hash_bd {
111 struct cfs_hash_bucket *bd_bucket; /**< address of bucket */
112 unsigned int bd_offset; /**< offset in bucket */
113 };
114
115 #define CFS_HASH_NAME_LEN 16 /**< default name length */
116 #define CFS_HASH_BIGNAME_LEN 64 /**< bigname for param tree */
117
118 #define CFS_HASH_BKT_BITS 3 /**< default bits of bucket */
119 #define CFS_HASH_BITS_MAX 30 /**< max bits of bucket */
120 #define CFS_HASH_BITS_MIN CFS_HASH_BKT_BITS
121
122 /**
123 * common hash attributes.
124 */
125 enum cfs_hash_tag {
126 /**
127 * don't need any lock, caller will protect operations with it's
128 * own lock. With this flag:
129 * . CFS_HASH_NO_BKTLOCK, CFS_HASH_RW_BKTLOCK, CFS_HASH_SPIN_BKTLOCK
130 * will be ignored.
131 * . Some functions will be disabled with this flag, i.e:
132 * cfs_hash_for_each_empty, cfs_hash_rehash
133 */
134 CFS_HASH_NO_LOCK = 1 << 0,
135 /** no bucket lock, use one spinlock to protect the whole hash */
136 CFS_HASH_NO_BKTLOCK = 1 << 1,
137 /** rwlock to protect bucket */
138 CFS_HASH_RW_BKTLOCK = 1 << 2,
139 /** spinlock to protect bucket */
140 CFS_HASH_SPIN_BKTLOCK = 1 << 3,
141 /** always add new item to tail */
142 CFS_HASH_ADD_TAIL = 1 << 4,
143 /** hash-table doesn't have refcount on item */
144 CFS_HASH_NO_ITEMREF = 1 << 5,
145 /** big name for param-tree */
146 CFS_HASH_BIGNAME = 1 << 6,
147 /** track global count */
148 CFS_HASH_COUNTER = 1 << 7,
149 /** rehash item by new key */
150 CFS_HASH_REHASH_KEY = 1 << 8,
151 /** Enable dynamic hash resizing */
152 CFS_HASH_REHASH = 1 << 9,
153 /** can shrink hash-size */
154 CFS_HASH_SHRINK = 1 << 10,
155 /** assert hash is empty on exit */
156 CFS_HASH_ASSERT_EMPTY = 1 << 11,
157 /** record hlist depth */
158 CFS_HASH_DEPTH = 1 << 12,
159 /**
160 * rehash is always scheduled in a different thread, so current
161 * change on hash table is non-blocking
162 */
163 CFS_HASH_NBLK_CHANGE = 1 << 13,
164 /** NB, we typed hs_flags as __u16, please change it
165 * if you need to extend >=16 flags */
166 };
167
168 /** most used attributes */
169 #define CFS_HASH_DEFAULT (CFS_HASH_RW_BKTLOCK | \
170 CFS_HASH_COUNTER | CFS_HASH_REHASH)
171
172 /**
173 * cfs_hash is a hash-table implementation for general purpose, it can support:
174 * . two refcount modes
175 * hash-table with & without refcount
176 * . four lock modes
177 * nolock, one-spinlock, rw-bucket-lock, spin-bucket-lock
178 * . general operations
179 * lookup, add(add_tail or add_head), delete
180 * . rehash
181 * grows or shrink
182 * . iteration
183 * locked iteration and unlocked iteration
184 * . bigname
185 * support long name hash
186 * . debug
187 * trace max searching depth
188 *
189 * Rehash:
190 * When the htable grows or shrinks, a separate task (cfs_hash_rehash_worker)
191 * is spawned to handle the rehash in the background, it's possible that other
192 * processes can concurrently perform additions, deletions, and lookups
193 * without being blocked on rehash completion, because rehash will release
194 * the global wrlock for each bucket.
195 *
196 * rehash and iteration can't run at the same time because it's too tricky
197 * to keep both of them safe and correct.
198 * As they are relatively rare operations, so:
199 * . if iteration is in progress while we try to launch rehash, then
200 * it just giveup, iterator will launch rehash at the end.
201 * . if rehash is in progress while we try to iterate the hash table,
202 * then we just wait (shouldn't be very long time), anyway, nobody
203 * should expect iteration of whole hash-table to be non-blocking.
204 *
205 * During rehashing, a (key,object) pair may be in one of two buckets,
206 * depending on whether the worker task has yet to transfer the object
207 * to its new location in the table. Lookups and deletions need to search both
208 * locations; additions must take care to only insert into the new bucket.
209 */
210
211 struct cfs_hash {
212 /** serialize with rehash, or serialize all operations if
213 * the hash-table has CFS_HASH_NO_BKTLOCK */
214 union cfs_hash_lock hs_lock;
215 /** hash operations */
216 struct cfs_hash_ops *hs_ops;
217 /** hash lock operations */
218 struct cfs_hash_lock_ops *hs_lops;
219 /** hash list operations */
220 struct cfs_hash_hlist_ops *hs_hops;
221 /** hash buckets-table */
222 struct cfs_hash_bucket **hs_buckets;
223 /** total number of items on this hash-table */
224 atomic_t hs_count;
225 /** hash flags, see cfs_hash_tag for detail */
226 __u16 hs_flags;
227 /** # of extra-bytes for bucket, for user saving extended attributes */
228 __u16 hs_extra_bytes;
229 /** wants to iterate */
230 __u8 hs_iterating;
231 /** hash-table is dying */
232 __u8 hs_exiting;
233 /** current hash bits */
234 __u8 hs_cur_bits;
235 /** min hash bits */
236 __u8 hs_min_bits;
237 /** max hash bits */
238 __u8 hs_max_bits;
239 /** bits for rehash */
240 __u8 hs_rehash_bits;
241 /** bits for each bucket */
242 __u8 hs_bkt_bits;
243 /** resize min threshold */
244 __u16 hs_min_theta;
245 /** resize max threshold */
246 __u16 hs_max_theta;
247 /** resize count */
248 __u32 hs_rehash_count;
249 /** # of iterators (caller of cfs_hash_for_each_*) */
250 __u32 hs_iterators;
251 /** rehash workitem */
252 cfs_workitem_t hs_rehash_wi;
253 /** refcount on this hash table */
254 atomic_t hs_refcount;
255 /** rehash buckets-table */
256 struct cfs_hash_bucket **hs_rehash_buckets;
257 #if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1
258 /** serialize debug members */
259 spinlock_t hs_dep_lock;
260 /** max depth */
261 unsigned int hs_dep_max;
262 /** id of the deepest bucket */
263 unsigned int hs_dep_bkt;
264 /** offset in the deepest bucket */
265 unsigned int hs_dep_off;
266 /** bits when we found the max depth */
267 unsigned int hs_dep_bits;
268 /** workitem to output max depth */
269 cfs_workitem_t hs_dep_wi;
270 #endif
271 /** name of htable */
272 char hs_name[0];
273 };
274
275 struct cfs_hash_lock_ops {
276 /** lock the hash table */
277 void (*hs_lock)(union cfs_hash_lock *lock, int exclusive);
278 /** unlock the hash table */
279 void (*hs_unlock)(union cfs_hash_lock *lock, int exclusive);
280 /** lock the hash bucket */
281 void (*hs_bkt_lock)(union cfs_hash_lock *lock, int exclusive);
282 /** unlock the hash bucket */
283 void (*hs_bkt_unlock)(union cfs_hash_lock *lock, int exclusive);
284 };
285
286 struct cfs_hash_hlist_ops {
287 /** return hlist_head of hash-head of @bd */
288 struct hlist_head *(*hop_hhead)(struct cfs_hash *hs,
289 struct cfs_hash_bd *bd);
290 /** return hash-head size */
291 int (*hop_hhead_size)(struct cfs_hash *hs);
292 /** add @hnode to hash-head of @bd */
293 int (*hop_hnode_add)(struct cfs_hash *hs, struct cfs_hash_bd *bd,
294 struct hlist_node *hnode);
295 /** remove @hnode from hash-head of @bd */
296 int (*hop_hnode_del)(struct cfs_hash *hs, struct cfs_hash_bd *bd,
297 struct hlist_node *hnode);
298 };
299
300 struct cfs_hash_ops {
301 /** return hashed value from @key */
302 unsigned (*hs_hash)(struct cfs_hash *hs, const void *key,
303 unsigned mask);
304 /** return key address of @hnode */
305 void * (*hs_key)(struct hlist_node *hnode);
306 /** copy key from @hnode to @key */
307 void (*hs_keycpy)(struct hlist_node *hnode, void *key);
308 /**
309 * compare @key with key of @hnode
310 * returns 1 on a match
311 */
312 int (*hs_keycmp)(const void *key, struct hlist_node *hnode);
313 /** return object address of @hnode, i.e: container_of(...hnode) */
314 void * (*hs_object)(struct hlist_node *hnode);
315 /** get refcount of item, always called with holding bucket-lock */
316 void (*hs_get)(struct cfs_hash *hs, struct hlist_node *hnode);
317 /** release refcount of item */
318 void (*hs_put)(struct cfs_hash *hs, struct hlist_node *hnode);
319 /** release refcount of item, always called with holding bucket-lock */
320 void (*hs_put_locked)(struct cfs_hash *hs,
321 struct hlist_node *hnode);
322 /** it's called before removing of @hnode */
323 void (*hs_exit)(struct cfs_hash *hs, struct hlist_node *hnode);
324 };
325
326 /** total number of buckets in @hs */
327 #define CFS_HASH_NBKT(hs) \
328 (1U << ((hs)->hs_cur_bits - (hs)->hs_bkt_bits))
329
330 /** total number of buckets in @hs while rehashing */
331 #define CFS_HASH_RH_NBKT(hs) \
332 (1U << ((hs)->hs_rehash_bits - (hs)->hs_bkt_bits))
333
334 /** number of hlist for in bucket */
335 #define CFS_HASH_BKT_NHLIST(hs) (1U << (hs)->hs_bkt_bits)
336
337 /** total number of hlist in @hs */
338 #define CFS_HASH_NHLIST(hs) (1U << (hs)->hs_cur_bits)
339
340 /** total number of hlist in @hs while rehashing */
341 #define CFS_HASH_RH_NHLIST(hs) (1U << (hs)->hs_rehash_bits)
342
343 static inline int
cfs_hash_with_no_lock(struct cfs_hash * hs)344 cfs_hash_with_no_lock(struct cfs_hash *hs)
345 {
346 /* caller will serialize all operations for this hash-table */
347 return (hs->hs_flags & CFS_HASH_NO_LOCK) != 0;
348 }
349
350 static inline int
cfs_hash_with_no_bktlock(struct cfs_hash * hs)351 cfs_hash_with_no_bktlock(struct cfs_hash *hs)
352 {
353 /* no bucket lock, one single lock to protect the hash-table */
354 return (hs->hs_flags & CFS_HASH_NO_BKTLOCK) != 0;
355 }
356
357 static inline int
cfs_hash_with_rw_bktlock(struct cfs_hash * hs)358 cfs_hash_with_rw_bktlock(struct cfs_hash *hs)
359 {
360 /* rwlock to protect hash bucket */
361 return (hs->hs_flags & CFS_HASH_RW_BKTLOCK) != 0;
362 }
363
364 static inline int
cfs_hash_with_spin_bktlock(struct cfs_hash * hs)365 cfs_hash_with_spin_bktlock(struct cfs_hash *hs)
366 {
367 /* spinlock to protect hash bucket */
368 return (hs->hs_flags & CFS_HASH_SPIN_BKTLOCK) != 0;
369 }
370
371 static inline int
cfs_hash_with_add_tail(struct cfs_hash * hs)372 cfs_hash_with_add_tail(struct cfs_hash *hs)
373 {
374 return (hs->hs_flags & CFS_HASH_ADD_TAIL) != 0;
375 }
376
377 static inline int
cfs_hash_with_no_itemref(struct cfs_hash * hs)378 cfs_hash_with_no_itemref(struct cfs_hash *hs)
379 {
380 /* hash-table doesn't keep refcount on item,
381 * item can't be removed from hash unless it's
382 * ZERO refcount */
383 return (hs->hs_flags & CFS_HASH_NO_ITEMREF) != 0;
384 }
385
386 static inline int
cfs_hash_with_bigname(struct cfs_hash * hs)387 cfs_hash_with_bigname(struct cfs_hash *hs)
388 {
389 return (hs->hs_flags & CFS_HASH_BIGNAME) != 0;
390 }
391
392 static inline int
cfs_hash_with_counter(struct cfs_hash * hs)393 cfs_hash_with_counter(struct cfs_hash *hs)
394 {
395 return (hs->hs_flags & CFS_HASH_COUNTER) != 0;
396 }
397
398 static inline int
cfs_hash_with_rehash(struct cfs_hash * hs)399 cfs_hash_with_rehash(struct cfs_hash *hs)
400 {
401 return (hs->hs_flags & CFS_HASH_REHASH) != 0;
402 }
403
404 static inline int
cfs_hash_with_rehash_key(struct cfs_hash * hs)405 cfs_hash_with_rehash_key(struct cfs_hash *hs)
406 {
407 return (hs->hs_flags & CFS_HASH_REHASH_KEY) != 0;
408 }
409
410 static inline int
cfs_hash_with_shrink(struct cfs_hash * hs)411 cfs_hash_with_shrink(struct cfs_hash *hs)
412 {
413 return (hs->hs_flags & CFS_HASH_SHRINK) != 0;
414 }
415
416 static inline int
cfs_hash_with_assert_empty(struct cfs_hash * hs)417 cfs_hash_with_assert_empty(struct cfs_hash *hs)
418 {
419 return (hs->hs_flags & CFS_HASH_ASSERT_EMPTY) != 0;
420 }
421
422 static inline int
cfs_hash_with_depth(struct cfs_hash * hs)423 cfs_hash_with_depth(struct cfs_hash *hs)
424 {
425 return (hs->hs_flags & CFS_HASH_DEPTH) != 0;
426 }
427
428 static inline int
cfs_hash_with_nblk_change(struct cfs_hash * hs)429 cfs_hash_with_nblk_change(struct cfs_hash *hs)
430 {
431 return (hs->hs_flags & CFS_HASH_NBLK_CHANGE) != 0;
432 }
433
434 static inline int
cfs_hash_is_exiting(struct cfs_hash * hs)435 cfs_hash_is_exiting(struct cfs_hash *hs)
436 { /* cfs_hash_destroy is called */
437 return hs->hs_exiting;
438 }
439
440 static inline int
cfs_hash_is_rehashing(struct cfs_hash * hs)441 cfs_hash_is_rehashing(struct cfs_hash *hs)
442 { /* rehash is launched */
443 return hs->hs_rehash_bits != 0;
444 }
445
446 static inline int
cfs_hash_is_iterating(struct cfs_hash * hs)447 cfs_hash_is_iterating(struct cfs_hash *hs)
448 { /* someone is calling cfs_hash_for_each_* */
449 return hs->hs_iterating || hs->hs_iterators != 0;
450 }
451
452 static inline int
cfs_hash_bkt_size(struct cfs_hash * hs)453 cfs_hash_bkt_size(struct cfs_hash *hs)
454 {
455 return offsetof(struct cfs_hash_bucket, hsb_head[0]) +
456 hs->hs_hops->hop_hhead_size(hs) * CFS_HASH_BKT_NHLIST(hs) +
457 hs->hs_extra_bytes;
458 }
459
460 static inline unsigned
cfs_hash_id(struct cfs_hash * hs,const void * key,unsigned mask)461 cfs_hash_id(struct cfs_hash *hs, const void *key, unsigned mask)
462 {
463 return hs->hs_ops->hs_hash(hs, key, mask);
464 }
465
466 static inline void *
cfs_hash_key(struct cfs_hash * hs,struct hlist_node * hnode)467 cfs_hash_key(struct cfs_hash *hs, struct hlist_node *hnode)
468 {
469 return hs->hs_ops->hs_key(hnode);
470 }
471
472 static inline void
cfs_hash_keycpy(struct cfs_hash * hs,struct hlist_node * hnode,void * key)473 cfs_hash_keycpy(struct cfs_hash *hs, struct hlist_node *hnode, void *key)
474 {
475 if (hs->hs_ops->hs_keycpy)
476 hs->hs_ops->hs_keycpy(hnode, key);
477 }
478
479 /**
480 * Returns 1 on a match,
481 */
482 static inline int
cfs_hash_keycmp(struct cfs_hash * hs,const void * key,struct hlist_node * hnode)483 cfs_hash_keycmp(struct cfs_hash *hs, const void *key, struct hlist_node *hnode)
484 {
485 return hs->hs_ops->hs_keycmp(key, hnode);
486 }
487
488 static inline void *
cfs_hash_object(struct cfs_hash * hs,struct hlist_node * hnode)489 cfs_hash_object(struct cfs_hash *hs, struct hlist_node *hnode)
490 {
491 return hs->hs_ops->hs_object(hnode);
492 }
493
494 static inline void
cfs_hash_get(struct cfs_hash * hs,struct hlist_node * hnode)495 cfs_hash_get(struct cfs_hash *hs, struct hlist_node *hnode)
496 {
497 return hs->hs_ops->hs_get(hs, hnode);
498 }
499
500 static inline void
cfs_hash_put_locked(struct cfs_hash * hs,struct hlist_node * hnode)501 cfs_hash_put_locked(struct cfs_hash *hs, struct hlist_node *hnode)
502 {
503 return hs->hs_ops->hs_put_locked(hs, hnode);
504 }
505
506 static inline void
cfs_hash_put(struct cfs_hash * hs,struct hlist_node * hnode)507 cfs_hash_put(struct cfs_hash *hs, struct hlist_node *hnode)
508 {
509 return hs->hs_ops->hs_put(hs, hnode);
510 }
511
512 static inline void
cfs_hash_exit(struct cfs_hash * hs,struct hlist_node * hnode)513 cfs_hash_exit(struct cfs_hash *hs, struct hlist_node *hnode)
514 {
515 if (hs->hs_ops->hs_exit)
516 hs->hs_ops->hs_exit(hs, hnode);
517 }
518
cfs_hash_lock(struct cfs_hash * hs,int excl)519 static inline void cfs_hash_lock(struct cfs_hash *hs, int excl)
520 {
521 hs->hs_lops->hs_lock(&hs->hs_lock, excl);
522 }
523
cfs_hash_unlock(struct cfs_hash * hs,int excl)524 static inline void cfs_hash_unlock(struct cfs_hash *hs, int excl)
525 {
526 hs->hs_lops->hs_unlock(&hs->hs_lock, excl);
527 }
528
cfs_hash_dec_and_lock(struct cfs_hash * hs,atomic_t * condition)529 static inline int cfs_hash_dec_and_lock(struct cfs_hash *hs,
530 atomic_t *condition)
531 {
532 LASSERT(cfs_hash_with_no_bktlock(hs));
533 return atomic_dec_and_lock(condition, &hs->hs_lock.spin);
534 }
535
cfs_hash_bd_lock(struct cfs_hash * hs,struct cfs_hash_bd * bd,int excl)536 static inline void cfs_hash_bd_lock(struct cfs_hash *hs,
537 struct cfs_hash_bd *bd, int excl)
538 {
539 hs->hs_lops->hs_bkt_lock(&bd->bd_bucket->hsb_lock, excl);
540 }
541
cfs_hash_bd_unlock(struct cfs_hash * hs,struct cfs_hash_bd * bd,int excl)542 static inline void cfs_hash_bd_unlock(struct cfs_hash *hs,
543 struct cfs_hash_bd *bd, int excl)
544 {
545 hs->hs_lops->hs_bkt_unlock(&bd->bd_bucket->hsb_lock, excl);
546 }
547
548 /**
549 * operations on cfs_hash bucket (bd: bucket descriptor),
550 * they are normally for hash-table without rehash
551 */
552 void cfs_hash_bd_get(struct cfs_hash *hs, const void *key,
553 struct cfs_hash_bd *bd);
554
555 static inline void
cfs_hash_bd_get_and_lock(struct cfs_hash * hs,const void * key,struct cfs_hash_bd * bd,int excl)556 cfs_hash_bd_get_and_lock(struct cfs_hash *hs, const void *key,
557 struct cfs_hash_bd *bd, int excl)
558 {
559 cfs_hash_bd_get(hs, key, bd);
560 cfs_hash_bd_lock(hs, bd, excl);
561 }
562
563 static inline unsigned
cfs_hash_bd_index_get(struct cfs_hash * hs,struct cfs_hash_bd * bd)564 cfs_hash_bd_index_get(struct cfs_hash *hs, struct cfs_hash_bd *bd)
565 {
566 return bd->bd_offset | (bd->bd_bucket->hsb_index << hs->hs_bkt_bits);
567 }
568
569 static inline void
cfs_hash_bd_index_set(struct cfs_hash * hs,unsigned index,struct cfs_hash_bd * bd)570 cfs_hash_bd_index_set(struct cfs_hash *hs, unsigned index,
571 struct cfs_hash_bd *bd)
572 {
573 bd->bd_bucket = hs->hs_buckets[index >> hs->hs_bkt_bits];
574 bd->bd_offset = index & (CFS_HASH_BKT_NHLIST(hs) - 1U);
575 }
576
577 static inline void *
cfs_hash_bd_extra_get(struct cfs_hash * hs,struct cfs_hash_bd * bd)578 cfs_hash_bd_extra_get(struct cfs_hash *hs, struct cfs_hash_bd *bd)
579 {
580 return (void *)bd->bd_bucket +
581 cfs_hash_bkt_size(hs) - hs->hs_extra_bytes;
582 }
583
584 static inline __u32
cfs_hash_bd_version_get(struct cfs_hash_bd * bd)585 cfs_hash_bd_version_get(struct cfs_hash_bd *bd)
586 {
587 /* need hold cfs_hash_bd_lock */
588 return bd->bd_bucket->hsb_version;
589 }
590
591 static inline __u32
cfs_hash_bd_count_get(struct cfs_hash_bd * bd)592 cfs_hash_bd_count_get(struct cfs_hash_bd *bd)
593 {
594 /* need hold cfs_hash_bd_lock */
595 return bd->bd_bucket->hsb_count;
596 }
597
598 static inline int
cfs_hash_bd_depmax_get(struct cfs_hash_bd * bd)599 cfs_hash_bd_depmax_get(struct cfs_hash_bd *bd)
600 {
601 return bd->bd_bucket->hsb_depmax;
602 }
603
604 static inline int
cfs_hash_bd_compare(struct cfs_hash_bd * bd1,struct cfs_hash_bd * bd2)605 cfs_hash_bd_compare(struct cfs_hash_bd *bd1, struct cfs_hash_bd *bd2)
606 {
607 if (bd1->bd_bucket->hsb_index != bd2->bd_bucket->hsb_index)
608 return bd1->bd_bucket->hsb_index - bd2->bd_bucket->hsb_index;
609
610 if (bd1->bd_offset != bd2->bd_offset)
611 return bd1->bd_offset - bd2->bd_offset;
612
613 return 0;
614 }
615
616 void cfs_hash_bd_add_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
617 struct hlist_node *hnode);
618 void cfs_hash_bd_del_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
619 struct hlist_node *hnode);
620 void cfs_hash_bd_move_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd_old,
621 struct cfs_hash_bd *bd_new,
622 struct hlist_node *hnode);
623
624 static inline int
cfs_hash_bd_dec_and_lock(struct cfs_hash * hs,struct cfs_hash_bd * bd,atomic_t * condition)625 cfs_hash_bd_dec_and_lock(struct cfs_hash *hs, struct cfs_hash_bd *bd,
626 atomic_t *condition)
627 {
628 LASSERT(cfs_hash_with_spin_bktlock(hs));
629 return atomic_dec_and_lock(condition, &bd->bd_bucket->hsb_lock.spin);
630 }
631
632 static inline struct hlist_head *
cfs_hash_bd_hhead(struct cfs_hash * hs,struct cfs_hash_bd * bd)633 cfs_hash_bd_hhead(struct cfs_hash *hs, struct cfs_hash_bd *bd)
634 {
635 return hs->hs_hops->hop_hhead(hs, bd);
636 }
637
638 struct hlist_node *
639 cfs_hash_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
640 const void *key);
641 struct hlist_node *
642 cfs_hash_bd_peek_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
643 const void *key);
644 struct hlist_node *
645 cfs_hash_bd_findadd_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
646 const void *key, struct hlist_node *hnode,
647 int insist_add);
648 struct hlist_node *
649 cfs_hash_bd_finddel_locked(struct cfs_hash *hs, struct cfs_hash_bd *bd,
650 const void *key, struct hlist_node *hnode);
651
652 /**
653 * operations on cfs_hash bucket (bd: bucket descriptor),
654 * they are safe for hash-table with rehash
655 */
656 void cfs_hash_dual_bd_get(struct cfs_hash *hs, const void *key,
657 struct cfs_hash_bd *bds);
658 void cfs_hash_dual_bd_lock(struct cfs_hash *hs, struct cfs_hash_bd *bds,
659 int excl);
660 void cfs_hash_dual_bd_unlock(struct cfs_hash *hs, struct cfs_hash_bd *bds,
661 int excl);
662
663 static inline void
cfs_hash_dual_bd_get_and_lock(struct cfs_hash * hs,const void * key,struct cfs_hash_bd * bds,int excl)664 cfs_hash_dual_bd_get_and_lock(struct cfs_hash *hs, const void *key,
665 struct cfs_hash_bd *bds, int excl)
666 {
667 cfs_hash_dual_bd_get(hs, key, bds);
668 cfs_hash_dual_bd_lock(hs, bds, excl);
669 }
670
671 struct hlist_node *
672 cfs_hash_dual_bd_lookup_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds,
673 const void *key);
674 struct hlist_node *
675 cfs_hash_dual_bd_findadd_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds,
676 const void *key, struct hlist_node *hnode,
677 int insist_add);
678 struct hlist_node *
679 cfs_hash_dual_bd_finddel_locked(struct cfs_hash *hs, struct cfs_hash_bd *bds,
680 const void *key, struct hlist_node *hnode);
681
682 /* Hash init/cleanup functions */
683 struct cfs_hash *
684 cfs_hash_create(char *name, unsigned cur_bits, unsigned max_bits,
685 unsigned bkt_bits, unsigned extra_bytes,
686 unsigned min_theta, unsigned max_theta,
687 struct cfs_hash_ops *ops, unsigned flags);
688
689 struct cfs_hash *cfs_hash_getref(struct cfs_hash *hs);
690 void cfs_hash_putref(struct cfs_hash *hs);
691
692 /* Hash addition functions */
693 void cfs_hash_add(struct cfs_hash *hs, const void *key,
694 struct hlist_node *hnode);
695 int cfs_hash_add_unique(struct cfs_hash *hs, const void *key,
696 struct hlist_node *hnode);
697 void *cfs_hash_findadd_unique(struct cfs_hash *hs, const void *key,
698 struct hlist_node *hnode);
699
700 /* Hash deletion functions */
701 void *cfs_hash_del(struct cfs_hash *hs, const void *key,
702 struct hlist_node *hnode);
703 void *cfs_hash_del_key(struct cfs_hash *hs, const void *key);
704
705 /* Hash lookup/for_each functions */
706 #define CFS_HASH_LOOP_HOG 1024
707
708 typedef int (*cfs_hash_for_each_cb_t)(struct cfs_hash *hs,
709 struct cfs_hash_bd *bd,
710 struct hlist_node *node,
711 void *data);
712 void *
713 cfs_hash_lookup(struct cfs_hash *hs, const void *key);
714 void
715 cfs_hash_for_each(struct cfs_hash *hs, cfs_hash_for_each_cb_t, void *data);
716 void
717 cfs_hash_for_each_safe(struct cfs_hash *hs, cfs_hash_for_each_cb_t, void *data);
718 int
719 cfs_hash_for_each_nolock(struct cfs_hash *hs, cfs_hash_for_each_cb_t,
720 void *data);
721 int
722 cfs_hash_for_each_empty(struct cfs_hash *hs, cfs_hash_for_each_cb_t,
723 void *data);
724 void
725 cfs_hash_for_each_key(struct cfs_hash *hs, const void *key,
726 cfs_hash_for_each_cb_t, void *data);
727 typedef int (*cfs_hash_cond_opt_cb_t)(void *obj, void *data);
728 void
729 cfs_hash_cond_del(struct cfs_hash *hs, cfs_hash_cond_opt_cb_t, void *data);
730
731 void
732 cfs_hash_hlist_for_each(struct cfs_hash *hs, unsigned hindex,
733 cfs_hash_for_each_cb_t, void *data);
734 int cfs_hash_is_empty(struct cfs_hash *hs);
735 __u64 cfs_hash_size_get(struct cfs_hash *hs);
736
737 /*
738 * Rehash - Theta is calculated to be the average chained
739 * hash depth assuming a perfectly uniform hash function.
740 */
741 void cfs_hash_rehash_cancel_locked(struct cfs_hash *hs);
742 void cfs_hash_rehash_cancel(struct cfs_hash *hs);
743 int cfs_hash_rehash(struct cfs_hash *hs, int do_rehash);
744 void cfs_hash_rehash_key(struct cfs_hash *hs, const void *old_key,
745 void *new_key, struct hlist_node *hnode);
746
747 #if CFS_HASH_DEBUG_LEVEL > CFS_HASH_DEBUG_1
748 /* Validate hnode references the correct key */
749 static inline void
cfs_hash_key_validate(struct cfs_hash * hs,const void * key,struct hlist_node * hnode)750 cfs_hash_key_validate(struct cfs_hash *hs, const void *key,
751 struct hlist_node *hnode)
752 {
753 LASSERT(cfs_hash_keycmp(hs, key, hnode));
754 }
755
756 /* Validate hnode is in the correct bucket */
757 static inline void
cfs_hash_bucket_validate(struct cfs_hash * hs,struct cfs_hash_bd * bd,struct hlist_node * hnode)758 cfs_hash_bucket_validate(struct cfs_hash *hs, struct cfs_hash_bd *bd,
759 struct hlist_node *hnode)
760 {
761 struct cfs_hash_bd bds[2];
762
763 cfs_hash_dual_bd_get(hs, cfs_hash_key(hs, hnode), bds);
764 LASSERT(bds[0].bd_bucket == bd->bd_bucket ||
765 bds[1].bd_bucket == bd->bd_bucket);
766 }
767
768 #else /* CFS_HASH_DEBUG_LEVEL > CFS_HASH_DEBUG_1 */
769
770 static inline void
cfs_hash_key_validate(struct cfs_hash * hs,const void * key,struct hlist_node * hnode)771 cfs_hash_key_validate(struct cfs_hash *hs, const void *key,
772 struct hlist_node *hnode) {}
773
774 static inline void
cfs_hash_bucket_validate(struct cfs_hash * hs,struct cfs_hash_bd * bd,struct hlist_node * hnode)775 cfs_hash_bucket_validate(struct cfs_hash *hs, struct cfs_hash_bd *bd,
776 struct hlist_node *hnode) {}
777
778 #endif /* CFS_HASH_DEBUG_LEVEL */
779
780 #define CFS_HASH_THETA_BITS 10
781 #define CFS_HASH_MIN_THETA (1U << (CFS_HASH_THETA_BITS - 1))
782 #define CFS_HASH_MAX_THETA (1U << (CFS_HASH_THETA_BITS + 1))
783
784 /* Return integer component of theta */
__cfs_hash_theta_int(int theta)785 static inline int __cfs_hash_theta_int(int theta)
786 {
787 return (theta >> CFS_HASH_THETA_BITS);
788 }
789
790 /* Return a fractional value between 0 and 999 */
__cfs_hash_theta_frac(int theta)791 static inline int __cfs_hash_theta_frac(int theta)
792 {
793 return ((theta * 1000) >> CFS_HASH_THETA_BITS) -
794 (__cfs_hash_theta_int(theta) * 1000);
795 }
796
__cfs_hash_theta(struct cfs_hash * hs)797 static inline int __cfs_hash_theta(struct cfs_hash *hs)
798 {
799 return (atomic_read(&hs->hs_count) <<
800 CFS_HASH_THETA_BITS) >> hs->hs_cur_bits;
801 }
802
803 static inline void
__cfs_hash_set_theta(struct cfs_hash * hs,int min,int max)804 __cfs_hash_set_theta(struct cfs_hash *hs, int min, int max)
805 {
806 LASSERT(min < max);
807 hs->hs_min_theta = (__u16)min;
808 hs->hs_max_theta = (__u16)max;
809 }
810
811 /* Generic debug formatting routines mainly for proc handler */
812 struct seq_file;
813 void cfs_hash_debug_header(struct seq_file *m);
814 void cfs_hash_debug_str(struct cfs_hash *hs, struct seq_file *m);
815
816 /*
817 * Generic djb2 hash algorithm for character arrays.
818 */
819 static inline unsigned
cfs_hash_djb2_hash(const void * key,size_t size,unsigned mask)820 cfs_hash_djb2_hash(const void *key, size_t size, unsigned mask)
821 {
822 unsigned i, hash = 5381;
823
824 LASSERT(key != NULL);
825
826 for (i = 0; i < size; i++)
827 hash = hash * 33 + ((char *)key)[i];
828
829 return (hash & mask);
830 }
831
832 /*
833 * Generic u32 hash algorithm.
834 */
835 static inline unsigned
cfs_hash_u32_hash(const __u32 key,unsigned mask)836 cfs_hash_u32_hash(const __u32 key, unsigned mask)
837 {
838 return ((key * CFS_GOLDEN_RATIO_PRIME_32) & mask);
839 }
840
841 /*
842 * Generic u64 hash algorithm.
843 */
844 static inline unsigned
cfs_hash_u64_hash(const __u64 key,unsigned mask)845 cfs_hash_u64_hash(const __u64 key, unsigned mask)
846 {
847 return ((unsigned)(key * CFS_GOLDEN_RATIO_PRIME_64) & mask);
848 }
849
850 /** iterate over all buckets in @bds (array of struct cfs_hash_bd) */
851 #define cfs_hash_for_each_bd(bds, n, i) \
852 for (i = 0; i < n && (bds)[i].bd_bucket != NULL; i++)
853
854 /** iterate over all buckets of @hs */
855 #define cfs_hash_for_each_bucket(hs, bd, pos) \
856 for (pos = 0; \
857 pos < CFS_HASH_NBKT(hs) && \
858 ((bd)->bd_bucket = (hs)->hs_buckets[pos]) != NULL; pos++)
859
860 /** iterate over all hlist of bucket @bd */
861 #define cfs_hash_bd_for_each_hlist(hs, bd, hlist) \
862 for ((bd)->bd_offset = 0; \
863 (bd)->bd_offset < CFS_HASH_BKT_NHLIST(hs) && \
864 (hlist = cfs_hash_bd_hhead(hs, bd)) != NULL; \
865 (bd)->bd_offset++)
866
867 /* !__LIBCFS__HASH_H__ */
868 #endif
869