1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 only,
10 * as published by the Free Software Foundation.
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13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License version 2 for more details (a copy is included
16 * in the LICENSE file that accompanied this code).
18 * You should have received a copy of the GNU General Public License
19 * version 2 along with this program; If not, see
20 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
29 * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
30 * Use is subject to license terms.
32 * Copyright (c) 2011, Whamcloud, Inc.
35 * This file is part of Lustre, http://www.lustre.org/
36 * Lustre is a trademark of Sun Microsystems, Inc.
38 * libcfs/libcfs/hash.c
40 * Implement a hash class for hash process in lustre system.
42 * Author: YuZhangyong <yzy@clusterfs.com>
44 * 2008-08-15: Brian Behlendorf <behlendorf1@llnl.gov>
45 * - Simplified API and improved documentation
46 * - Added per-hash feature flags:
47 * * CFS_HASH_DEBUG additional validation
48 * * CFS_HASH_REHASH dynamic rehashing
49 * - Added per-hash statistics
50 * - General performance enhancements
52 * 2009-07-31: Liang Zhen <zhen.liang@sun.com>
53 * - move all stuff to libcfs
54 * - don't allow cur_bits != max_bits without setting of CFS_HASH_REHASH
55 * - ignore hs_rwlock if without CFS_HASH_REHASH setting
56 * - buckets are allocated one by one(intead of contiguous memory),
57 * to avoid unnecessary cacheline conflict
59 * 2010-03-01: Liang Zhen <zhen.liang@sun.com>
60 * - "bucket" is a group of hlist_head now, user can speicify bucket size
61 * by bkt_bits of cfs_hash_create(), all hlist_heads in a bucket share
62 * one lock for reducing memory overhead.
64 * - support lockless hash, caller will take care of locks:
65 * avoid lock overhead for hash tables that are already protected
66 * by locking in the caller for another reason
68 * - support both spin_lock/rwlock for bucket:
69 * overhead of spinlock contention is lower than read/write
70 * contention of rwlock, so using spinlock to serialize operations on
71 * bucket is more reasonable for those frequently changed hash tables
73 * - support one-single lock mode:
74 * one lock to protect all hash operations to avoid overhead of
75 * multiple locks if hash table is always small
77 * - removed a lot of unnecessary addref & decref on hash element:
78 * addref & decref are atomic operations in many use-cases which
81 * - support non-blocking cfs_hash_add() and cfs_hash_findadd():
82 * some lustre use-cases require these functions to be strictly
83 * non-blocking, we need to schedule required rehash on a different
84 * thread on those cases.
86 * - safer rehash on large hash table
87 * In old implementation, rehash function will exclusively lock the
88 * hash table and finish rehash in one batch, it's dangerous on SMP
89 * system because rehash millions of elements could take long time.
90 * New implemented rehash can release lock and relax CPU in middle
91 * of rehash, it's safe for another thread to search/change on the
92 * hash table even it's in rehasing.
94 * - support two different refcount modes
95 * . hash table has refcount on element
96 * . hash table doesn't change refcount on adding/removing element
98 * - support long name hash table (for param-tree)
100 * - fix a bug for cfs_hash_rehash_key:
101 * in old implementation, cfs_hash_rehash_key could screw up the
102 * hash-table because @key is overwritten without any protection.
103 * Now we need user to define hs_keycpy for those rehash enabled
104 * hash tables, cfs_hash_rehash_key will overwrite hash-key
105 * inside lock by calling hs_keycpy.
107 * - better hash iteration:
108 * Now we support both locked iteration & lockless iteration of hash
109 * table. Also, user can break the iteration by return 1 in callback.
112 #include <libcfs/libcfs.h>
114 #if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1
115 static unsigned int warn_on_depth = 8;
116 CFS_MODULE_PARM(warn_on_depth, "i", uint, 0644,
117 "warning when hash depth is high.");
121 cfs_hash_nl_lock(cfs_hash_lock_t *lock, int exclusive) {}
124 cfs_hash_nl_unlock(cfs_hash_lock_t *lock, int exclusive) {}
127 cfs_hash_spin_lock(cfs_hash_lock_t *lock, int exclusive)
129 cfs_spin_lock(&lock->spin);
133 cfs_hash_spin_unlock(cfs_hash_lock_t *lock, int exclusive)
135 cfs_spin_unlock(&lock->spin);
139 cfs_hash_rw_lock(cfs_hash_lock_t *lock, int exclusive)
142 cfs_read_lock(&lock->rw);
144 cfs_write_lock(&lock->rw);
148 cfs_hash_rw_unlock(cfs_hash_lock_t *lock, int exclusive)
151 cfs_read_unlock(&lock->rw);
153 cfs_write_unlock(&lock->rw);
157 static cfs_hash_lock_ops_t cfs_hash_nl_lops =
159 .hs_lock = cfs_hash_nl_lock,
160 .hs_unlock = cfs_hash_nl_unlock,
161 .hs_bkt_lock = cfs_hash_nl_lock,
162 .hs_bkt_unlock = cfs_hash_nl_unlock,
165 /** no bucket lock, one spinlock to protect everything */
166 static cfs_hash_lock_ops_t cfs_hash_nbl_lops =
168 .hs_lock = cfs_hash_spin_lock,
169 .hs_unlock = cfs_hash_spin_unlock,
170 .hs_bkt_lock = cfs_hash_nl_lock,
171 .hs_bkt_unlock = cfs_hash_nl_unlock,
174 /** spin bucket lock, rehash is enabled */
175 static cfs_hash_lock_ops_t cfs_hash_bkt_spin_lops =
177 .hs_lock = cfs_hash_rw_lock,
178 .hs_unlock = cfs_hash_rw_unlock,
179 .hs_bkt_lock = cfs_hash_spin_lock,
180 .hs_bkt_unlock = cfs_hash_spin_unlock,
183 /** rw bucket lock, rehash is enabled */
184 static cfs_hash_lock_ops_t cfs_hash_bkt_rw_lops =
186 .hs_lock = cfs_hash_rw_lock,
187 .hs_unlock = cfs_hash_rw_unlock,
188 .hs_bkt_lock = cfs_hash_rw_lock,
189 .hs_bkt_unlock = cfs_hash_rw_unlock,
192 /** spin bucket lock, rehash is disabled */
193 static cfs_hash_lock_ops_t cfs_hash_nr_bkt_spin_lops =
195 .hs_lock = cfs_hash_nl_lock,
196 .hs_unlock = cfs_hash_nl_unlock,
197 .hs_bkt_lock = cfs_hash_spin_lock,
198 .hs_bkt_unlock = cfs_hash_spin_unlock,
201 /** rw bucket lock, rehash is disabled */
202 static cfs_hash_lock_ops_t cfs_hash_nr_bkt_rw_lops =
204 .hs_lock = cfs_hash_nl_lock,
205 .hs_unlock = cfs_hash_nl_unlock,
206 .hs_bkt_lock = cfs_hash_rw_lock,
207 .hs_bkt_unlock = cfs_hash_rw_unlock,
211 cfs_hash_lock_setup(cfs_hash_t *hs)
213 if (cfs_hash_with_no_lock(hs)) {
214 hs->hs_lops = &cfs_hash_nl_lops;
216 } else if (cfs_hash_with_no_bktlock(hs)) {
217 hs->hs_lops = &cfs_hash_nbl_lops;
218 cfs_spin_lock_init(&hs->hs_lock.spin);
220 } else if (cfs_hash_with_rehash(hs)) {
221 cfs_rwlock_init(&hs->hs_lock.rw);
223 if (cfs_hash_with_rw_bktlock(hs))
224 hs->hs_lops = &cfs_hash_bkt_rw_lops;
225 else if (cfs_hash_with_spin_bktlock(hs))
226 hs->hs_lops = &cfs_hash_bkt_spin_lops;
230 if (cfs_hash_with_rw_bktlock(hs))
231 hs->hs_lops = &cfs_hash_nr_bkt_rw_lops;
232 else if (cfs_hash_with_spin_bktlock(hs))
233 hs->hs_lops = &cfs_hash_nr_bkt_spin_lops;
240 * Simple hash head without depth tracking
241 * new element is always added to head of hlist
244 cfs_hlist_head_t hh_head; /**< entries list */
248 cfs_hash_hh_hhead_size(cfs_hash_t *hs)
250 return sizeof(cfs_hash_head_t);
253 static cfs_hlist_head_t *
254 cfs_hash_hh_hhead(cfs_hash_t *hs, cfs_hash_bd_t *bd)
256 cfs_hash_head_t *head = (cfs_hash_head_t *)&bd->bd_bucket->hsb_head[0];
258 return &head[bd->bd_offset].hh_head;
262 cfs_hash_hh_hnode_add(cfs_hash_t *hs, cfs_hash_bd_t *bd,
263 cfs_hlist_node_t *hnode)
265 cfs_hlist_add_head(hnode, cfs_hash_hh_hhead(hs, bd));
266 return -1; /* unknown depth */
270 cfs_hash_hh_hnode_del(cfs_hash_t *hs, cfs_hash_bd_t *bd,
271 cfs_hlist_node_t *hnode)
273 cfs_hlist_del_init(hnode);
274 return -1; /* unknown depth */
278 * Simple hash head with depth tracking
279 * new element is always added to head of hlist
282 cfs_hlist_head_t hd_head; /**< entries list */
283 unsigned int hd_depth; /**< list length */
284 } cfs_hash_head_dep_t;
287 cfs_hash_hd_hhead_size(cfs_hash_t *hs)
289 return sizeof(cfs_hash_head_dep_t);
292 static cfs_hlist_head_t *
293 cfs_hash_hd_hhead(cfs_hash_t *hs, cfs_hash_bd_t *bd)
295 cfs_hash_head_dep_t *head;
297 head = (cfs_hash_head_dep_t *)&bd->bd_bucket->hsb_head[0];
298 return &head[bd->bd_offset].hd_head;
302 cfs_hash_hd_hnode_add(cfs_hash_t *hs, cfs_hash_bd_t *bd,
303 cfs_hlist_node_t *hnode)
305 cfs_hash_head_dep_t *hh = container_of(cfs_hash_hd_hhead(hs, bd),
306 cfs_hash_head_dep_t, hd_head);
307 cfs_hlist_add_head(hnode, &hh->hd_head);
308 return ++hh->hd_depth;
312 cfs_hash_hd_hnode_del(cfs_hash_t *hs, cfs_hash_bd_t *bd,
313 cfs_hlist_node_t *hnode)
315 cfs_hash_head_dep_t *hh = container_of(cfs_hash_hd_hhead(hs, bd),
316 cfs_hash_head_dep_t, hd_head);
317 cfs_hlist_del_init(hnode);
318 return --hh->hd_depth;
322 * double links hash head without depth tracking
323 * new element is always added to tail of hlist
326 cfs_hlist_head_t dh_head; /**< entries list */
327 cfs_hlist_node_t *dh_tail; /**< the last entry */
331 cfs_hash_dh_hhead_size(cfs_hash_t *hs)
333 return sizeof(cfs_hash_dhead_t);
336 static cfs_hlist_head_t *
337 cfs_hash_dh_hhead(cfs_hash_t *hs, cfs_hash_bd_t *bd)
339 cfs_hash_dhead_t *head;
341 head = (cfs_hash_dhead_t *)&bd->bd_bucket->hsb_head[0];
342 return &head[bd->bd_offset].dh_head;
346 cfs_hash_dh_hnode_add(cfs_hash_t *hs, cfs_hash_bd_t *bd,
347 cfs_hlist_node_t *hnode)
349 cfs_hash_dhead_t *dh = container_of(cfs_hash_dh_hhead(hs, bd),
350 cfs_hash_dhead_t, dh_head);
352 if (dh->dh_tail != NULL) /* not empty */
353 cfs_hlist_add_after(dh->dh_tail, hnode);
354 else /* empty list */
355 cfs_hlist_add_head(hnode, &dh->dh_head);
357 return -1; /* unknown depth */
361 cfs_hash_dh_hnode_del(cfs_hash_t *hs, cfs_hash_bd_t *bd,
362 cfs_hlist_node_t *hnd)
364 cfs_hash_dhead_t *dh = container_of(cfs_hash_dh_hhead(hs, bd),
365 cfs_hash_dhead_t, dh_head);
367 if (hnd->next == NULL) { /* it's the tail */
368 dh->dh_tail = (hnd->pprev == &dh->dh_head.first) ? NULL :
369 container_of(hnd->pprev, cfs_hlist_node_t, next);
371 cfs_hlist_del_init(hnd);
372 return -1; /* unknown depth */
376 * double links hash head with depth tracking
377 * new element is always added to tail of hlist
380 cfs_hlist_head_t dd_head; /**< entries list */
381 cfs_hlist_node_t *dd_tail; /**< the last entry */
382 unsigned int dd_depth; /**< list length */
383 } cfs_hash_dhead_dep_t;
386 cfs_hash_dd_hhead_size(cfs_hash_t *hs)
388 return sizeof(cfs_hash_dhead_dep_t);
391 static cfs_hlist_head_t *
392 cfs_hash_dd_hhead(cfs_hash_t *hs, cfs_hash_bd_t *bd)
394 cfs_hash_dhead_dep_t *head;
396 head = (cfs_hash_dhead_dep_t *)&bd->bd_bucket->hsb_head[0];
397 return &head[bd->bd_offset].dd_head;
401 cfs_hash_dd_hnode_add(cfs_hash_t *hs, cfs_hash_bd_t *bd,
402 cfs_hlist_node_t *hnode)
404 cfs_hash_dhead_dep_t *dh = container_of(cfs_hash_dd_hhead(hs, bd),
405 cfs_hash_dhead_dep_t, dd_head);
407 if (dh->dd_tail != NULL) /* not empty */
408 cfs_hlist_add_after(dh->dd_tail, hnode);
409 else /* empty list */
410 cfs_hlist_add_head(hnode, &dh->dd_head);
412 return ++dh->dd_depth;
416 cfs_hash_dd_hnode_del(cfs_hash_t *hs, cfs_hash_bd_t *bd,
417 cfs_hlist_node_t *hnd)
419 cfs_hash_dhead_dep_t *dh = container_of(cfs_hash_dd_hhead(hs, bd),
420 cfs_hash_dhead_dep_t, dd_head);
422 if (hnd->next == NULL) { /* it's the tail */
423 dh->dd_tail = (hnd->pprev == &dh->dd_head.first) ? NULL :
424 container_of(hnd->pprev, cfs_hlist_node_t, next);
426 cfs_hlist_del_init(hnd);
427 return --dh->dd_depth;
430 static cfs_hash_hlist_ops_t cfs_hash_hh_hops = {
431 .hop_hhead = cfs_hash_hh_hhead,
432 .hop_hhead_size = cfs_hash_hh_hhead_size,
433 .hop_hnode_add = cfs_hash_hh_hnode_add,
434 .hop_hnode_del = cfs_hash_hh_hnode_del,
437 static cfs_hash_hlist_ops_t cfs_hash_hd_hops = {
438 .hop_hhead = cfs_hash_hd_hhead,
439 .hop_hhead_size = cfs_hash_hd_hhead_size,
440 .hop_hnode_add = cfs_hash_hd_hnode_add,
441 .hop_hnode_del = cfs_hash_hd_hnode_del,
444 static cfs_hash_hlist_ops_t cfs_hash_dh_hops = {
445 .hop_hhead = cfs_hash_dh_hhead,
446 .hop_hhead_size = cfs_hash_dh_hhead_size,
447 .hop_hnode_add = cfs_hash_dh_hnode_add,
448 .hop_hnode_del = cfs_hash_dh_hnode_del,
451 static cfs_hash_hlist_ops_t cfs_hash_dd_hops = {
452 .hop_hhead = cfs_hash_dd_hhead,
453 .hop_hhead_size = cfs_hash_dd_hhead_size,
454 .hop_hnode_add = cfs_hash_dd_hnode_add,
455 .hop_hnode_del = cfs_hash_dd_hnode_del,
459 cfs_hash_hlist_setup(cfs_hash_t *hs)
461 if (cfs_hash_with_add_tail(hs)) {
462 hs->hs_hops = cfs_hash_with_depth(hs) ?
463 &cfs_hash_dd_hops : &cfs_hash_dh_hops;
465 hs->hs_hops = cfs_hash_with_depth(hs) ?
466 &cfs_hash_hd_hops : &cfs_hash_hh_hops;
471 cfs_hash_bd_from_key(cfs_hash_t *hs, cfs_hash_bucket_t **bkts,
472 unsigned int bits, const void *key, cfs_hash_bd_t *bd)
474 unsigned int index = cfs_hash_id(hs, key, (1U << bits) - 1);
476 LASSERT(bits == hs->hs_cur_bits || bits == hs->hs_rehash_bits);
478 bd->bd_bucket = bkts[index & ((1U << (bits - hs->hs_bkt_bits)) - 1)];
479 bd->bd_offset = index >> (bits - hs->hs_bkt_bits);
483 cfs_hash_bd_get(cfs_hash_t *hs, const void *key, cfs_hash_bd_t *bd)
485 /* NB: caller should hold hs->hs_rwlock if REHASH is set */
486 if (likely(hs->hs_rehash_buckets == NULL)) {
487 cfs_hash_bd_from_key(hs, hs->hs_buckets,
488 hs->hs_cur_bits, key, bd);
490 LASSERT(hs->hs_rehash_bits != 0);
491 cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets,
492 hs->hs_rehash_bits, key, bd);
495 CFS_EXPORT_SYMBOL(cfs_hash_bd_get);
498 cfs_hash_bd_dep_record(cfs_hash_t *hs, cfs_hash_bd_t *bd, int dep_cur)
500 if (likely(dep_cur <= bd->bd_bucket->hsb_depmax))
503 bd->bd_bucket->hsb_depmax = dep_cur;
504 # if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1
505 if (likely(warn_on_depth == 0 ||
506 max(warn_on_depth, hs->hs_dep_max) >= dep_cur))
509 cfs_spin_lock(&hs->hs_dep_lock);
510 hs->hs_dep_max = dep_cur;
511 hs->hs_dep_bkt = bd->bd_bucket->hsb_index;
512 hs->hs_dep_off = bd->bd_offset;
513 hs->hs_dep_bits = hs->hs_cur_bits;
514 cfs_spin_unlock(&hs->hs_dep_lock);
516 cfs_wi_schedule(&hs->hs_dep_wi);
521 cfs_hash_bd_add_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
522 cfs_hlist_node_t *hnode)
526 rc = hs->hs_hops->hop_hnode_add(hs, bd, hnode);
527 cfs_hash_bd_dep_record(hs, bd, rc);
528 bd->bd_bucket->hsb_version++;
529 if (unlikely(bd->bd_bucket->hsb_version == 0))
530 bd->bd_bucket->hsb_version++;
531 bd->bd_bucket->hsb_count++;
533 if (cfs_hash_with_counter(hs))
534 cfs_atomic_inc(&hs->hs_count);
535 if (!cfs_hash_with_no_itemref(hs))
536 cfs_hash_get(hs, hnode);
538 CFS_EXPORT_SYMBOL(cfs_hash_bd_add_locked);
541 cfs_hash_bd_del_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
542 cfs_hlist_node_t *hnode)
544 hs->hs_hops->hop_hnode_del(hs, bd, hnode);
546 LASSERT(bd->bd_bucket->hsb_count > 0);
547 bd->bd_bucket->hsb_count--;
548 bd->bd_bucket->hsb_version++;
549 if (unlikely(bd->bd_bucket->hsb_version == 0))
550 bd->bd_bucket->hsb_version++;
552 if (cfs_hash_with_counter(hs)) {
553 LASSERT(cfs_atomic_read(&hs->hs_count) > 0);
554 cfs_atomic_dec(&hs->hs_count);
556 if (!cfs_hash_with_no_itemref(hs))
557 cfs_hash_put_locked(hs, hnode);
559 CFS_EXPORT_SYMBOL(cfs_hash_bd_del_locked);
562 cfs_hash_bd_move_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd_old,
563 cfs_hash_bd_t *bd_new, cfs_hlist_node_t *hnode)
565 cfs_hash_bucket_t *obkt = bd_old->bd_bucket;
566 cfs_hash_bucket_t *nbkt = bd_new->bd_bucket;
569 if (cfs_hash_bd_compare(bd_old, bd_new) == 0)
572 /* use cfs_hash_bd_hnode_add/del, to avoid atomic & refcount ops
573 * in cfs_hash_bd_del/add_locked */
574 hs->hs_hops->hop_hnode_del(hs, bd_old, hnode);
575 rc = hs->hs_hops->hop_hnode_add(hs, bd_new, hnode);
576 cfs_hash_bd_dep_record(hs, bd_new, rc);
578 LASSERT(obkt->hsb_count > 0);
581 if (unlikely(obkt->hsb_version == 0))
585 if (unlikely(nbkt->hsb_version == 0))
588 CFS_EXPORT_SYMBOL(cfs_hash_bd_move_locked);
591 /** always set, for sanity (avoid ZERO intent) */
592 CFS_HS_LOOKUP_MASK_FIND = 1 << 0,
593 /** return entry with a ref */
594 CFS_HS_LOOKUP_MASK_REF = 1 << 1,
595 /** add entry if not existing */
596 CFS_HS_LOOKUP_MASK_ADD = 1 << 2,
597 /** delete entry, ignore other masks */
598 CFS_HS_LOOKUP_MASK_DEL = 1 << 3,
601 typedef enum cfs_hash_lookup_intent {
602 /** return item w/o refcount */
603 CFS_HS_LOOKUP_IT_PEEK = CFS_HS_LOOKUP_MASK_FIND,
604 /** return item with refcount */
605 CFS_HS_LOOKUP_IT_FIND = (CFS_HS_LOOKUP_MASK_FIND |
606 CFS_HS_LOOKUP_MASK_REF),
607 /** return item w/o refcount if existed, otherwise add */
608 CFS_HS_LOOKUP_IT_ADD = (CFS_HS_LOOKUP_MASK_FIND |
609 CFS_HS_LOOKUP_MASK_ADD),
610 /** return item with refcount if existed, otherwise add */
611 CFS_HS_LOOKUP_IT_FINDADD = (CFS_HS_LOOKUP_IT_FIND |
612 CFS_HS_LOOKUP_MASK_ADD),
613 /** delete if existed */
614 CFS_HS_LOOKUP_IT_FINDDEL = (CFS_HS_LOOKUP_MASK_FIND |
615 CFS_HS_LOOKUP_MASK_DEL)
616 } cfs_hash_lookup_intent_t;
618 static cfs_hlist_node_t *
619 cfs_hash_bd_lookup_intent(cfs_hash_t *hs, cfs_hash_bd_t *bd,
620 const void *key, cfs_hlist_node_t *hnode,
621 cfs_hash_lookup_intent_t intent)
624 cfs_hlist_head_t *hhead = cfs_hash_bd_hhead(hs, bd);
625 cfs_hlist_node_t *ehnode;
626 cfs_hlist_node_t *match;
627 int intent_add = (intent & CFS_HS_LOOKUP_MASK_ADD) != 0;
629 /* with this function, we can avoid a lot of useless refcount ops,
630 * which are expensive atomic operations most time. */
631 match = intent_add ? NULL : hnode;
632 cfs_hlist_for_each(ehnode, hhead) {
633 if (!cfs_hash_keycmp(hs, key, ehnode))
636 if (match != NULL && match != ehnode) /* can't match */
640 if ((intent & CFS_HS_LOOKUP_MASK_DEL) != 0) {
641 cfs_hash_bd_del_locked(hs, bd, ehnode);
645 /* caller wants refcount? */
646 if ((intent & CFS_HS_LOOKUP_MASK_REF) != 0)
647 cfs_hash_get(hs, ehnode);
654 LASSERT(hnode != NULL);
655 cfs_hash_bd_add_locked(hs, bd, hnode);
660 cfs_hash_bd_lookup_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd, const void *key)
662 return cfs_hash_bd_lookup_intent(hs, bd, key, NULL,
663 CFS_HS_LOOKUP_IT_FIND);
665 CFS_EXPORT_SYMBOL(cfs_hash_bd_lookup_locked);
668 cfs_hash_bd_findadd_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
669 const void *key, cfs_hlist_node_t *hnode,
672 return cfs_hash_bd_lookup_intent(hs, bd, key, hnode,
673 CFS_HS_LOOKUP_IT_ADD |
674 (!noref * CFS_HS_LOOKUP_MASK_REF));
676 CFS_EXPORT_SYMBOL(cfs_hash_bd_findadd_locked);
679 cfs_hash_bd_finddel_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
680 const void *key, cfs_hlist_node_t *hnode)
682 /* hnode can be NULL, we find the first item with @key */
683 return cfs_hash_bd_lookup_intent(hs, bd, key, hnode,
684 CFS_HS_LOOKUP_IT_FINDDEL);
686 CFS_EXPORT_SYMBOL(cfs_hash_bd_finddel_locked);
689 cfs_hash_multi_bd_lock(cfs_hash_t *hs, cfs_hash_bd_t *bds,
690 unsigned n, int excl)
692 cfs_hash_bucket_t *prev = NULL;
696 * bds must be ascendantly ordered by bd->bd_bucket->hsb_index.
697 * NB: it's possible that several bds point to the same bucket but
698 * have different bd::bd_offset, so need take care of deadlock.
700 cfs_hash_for_each_bd(bds, n, i) {
701 if (prev == bds[i].bd_bucket)
704 LASSERT(prev == NULL ||
705 prev->hsb_index < bds[i].bd_bucket->hsb_index);
706 cfs_hash_bd_lock(hs, &bds[i], excl);
707 prev = bds[i].bd_bucket;
712 cfs_hash_multi_bd_unlock(cfs_hash_t *hs, cfs_hash_bd_t *bds,
713 unsigned n, int excl)
715 cfs_hash_bucket_t *prev = NULL;
718 cfs_hash_for_each_bd(bds, n, i) {
719 if (prev != bds[i].bd_bucket) {
720 cfs_hash_bd_unlock(hs, &bds[i], excl);
721 prev = bds[i].bd_bucket;
726 static cfs_hlist_node_t *
727 cfs_hash_multi_bd_lookup_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds,
728 unsigned n, const void *key)
730 cfs_hlist_node_t *ehnode;
733 cfs_hash_for_each_bd(bds, n, i) {
734 ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, NULL,
735 CFS_HS_LOOKUP_IT_FIND);
742 static cfs_hlist_node_t *
743 cfs_hash_multi_bd_findadd_locked(cfs_hash_t *hs,
744 cfs_hash_bd_t *bds, unsigned n, const void *key,
745 cfs_hlist_node_t *hnode, int noref)
747 cfs_hlist_node_t *ehnode;
751 LASSERT(hnode != NULL);
752 intent = CFS_HS_LOOKUP_IT_PEEK | (!noref * CFS_HS_LOOKUP_MASK_REF);
754 cfs_hash_for_each_bd(bds, n, i) {
755 ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key,
761 if (i == 1) { /* only one bucket */
762 cfs_hash_bd_add_locked(hs, &bds[0], hnode);
766 cfs_hash_bd_get(hs, key, &mybd);
767 cfs_hash_bd_add_locked(hs, &mybd, hnode);
773 static cfs_hlist_node_t *
774 cfs_hash_multi_bd_finddel_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds,
775 unsigned n, const void *key,
776 cfs_hlist_node_t *hnode)
778 cfs_hlist_node_t *ehnode;
781 cfs_hash_for_each_bd(bds, n, i) {
782 ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, hnode,
783 CFS_HS_LOOKUP_IT_FINDDEL);
791 cfs_hash_bd_order(cfs_hash_bd_t *bd1, cfs_hash_bd_t *bd2)
795 if (bd2->bd_bucket == NULL)
798 if (bd1->bd_bucket == NULL) {
800 bd2->bd_bucket = NULL;
804 rc = cfs_hash_bd_compare(bd1, bd2);
806 bd2->bd_bucket = NULL;
808 } else if (rc > 0) { /* swab bd1 and bd2 */
818 cfs_hash_dual_bd_get(cfs_hash_t *hs, const void *key, cfs_hash_bd_t *bds)
820 /* NB: caller should hold hs_lock.rw if REHASH is set */
821 cfs_hash_bd_from_key(hs, hs->hs_buckets,
822 hs->hs_cur_bits, key, &bds[0]);
823 if (likely(hs->hs_rehash_buckets == NULL)) {
824 /* no rehash or not rehashing */
825 bds[1].bd_bucket = NULL;
829 LASSERT(hs->hs_rehash_bits != 0);
830 cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets,
831 hs->hs_rehash_bits, key, &bds[1]);
833 cfs_hash_bd_order(&bds[0], &bds[1]);
835 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_get);
838 cfs_hash_dual_bd_lock(cfs_hash_t *hs, cfs_hash_bd_t *bds, int excl)
840 cfs_hash_multi_bd_lock(hs, bds, 2, excl);
842 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_lock);
845 cfs_hash_dual_bd_unlock(cfs_hash_t *hs, cfs_hash_bd_t *bds, int excl)
847 cfs_hash_multi_bd_unlock(hs, bds, 2, excl);
849 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_unlock);
852 cfs_hash_dual_bd_lookup_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds,
855 return cfs_hash_multi_bd_lookup_locked(hs, bds, 2, key);
857 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_lookup_locked);
860 cfs_hash_dual_bd_findadd_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds,
861 const void *key, cfs_hlist_node_t *hnode,
864 return cfs_hash_multi_bd_findadd_locked(hs, bds, 2, key,
867 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_findadd_locked);
870 cfs_hash_dual_bd_finddel_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds,
871 const void *key, cfs_hlist_node_t *hnode)
873 return cfs_hash_multi_bd_finddel_locked(hs, bds, 2, key, hnode);
875 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_finddel_locked);
878 cfs_hash_buckets_free(cfs_hash_bucket_t **buckets,
879 int bkt_size, int prev_size, int size)
883 for (i = prev_size; i < size; i++) {
884 if (buckets[i] != NULL)
885 LIBCFS_FREE(buckets[i], bkt_size);
888 LIBCFS_FREE(buckets, sizeof(buckets[0]) * size);
892 * Create or grow bucket memory. Return old_buckets if no allocation was
893 * needed, the newly allocated buckets if allocation was needed and
894 * successful, and NULL on error.
896 static cfs_hash_bucket_t **
897 cfs_hash_buckets_realloc(cfs_hash_t *hs, cfs_hash_bucket_t **old_bkts,
898 unsigned int old_size, unsigned int new_size)
900 cfs_hash_bucket_t **new_bkts;
903 LASSERT(old_size == 0 || old_bkts != NULL);
905 if (old_bkts != NULL && old_size == new_size)
908 LIBCFS_ALLOC(new_bkts, sizeof(new_bkts[0]) * new_size);
909 if (new_bkts == NULL)
912 if (old_bkts != NULL) {
913 memcpy(new_bkts, old_bkts,
914 min(old_size, new_size) * sizeof(*old_bkts));
917 for (i = old_size; i < new_size; i++) {
918 cfs_hlist_head_t *hhead;
921 LIBCFS_ALLOC(new_bkts[i], cfs_hash_bkt_size(hs));
922 if (new_bkts[i] == NULL) {
923 cfs_hash_buckets_free(new_bkts, cfs_hash_bkt_size(hs),
928 new_bkts[i]->hsb_index = i;
929 new_bkts[i]->hsb_version = 1; /* shouldn't be zero */
930 new_bkts[i]->hsb_depmax = -1; /* unknown */
931 bd.bd_bucket = new_bkts[i];
932 cfs_hash_bd_for_each_hlist(hs, &bd, hhead)
933 CFS_INIT_HLIST_HEAD(hhead);
935 if (cfs_hash_with_no_lock(hs) ||
936 cfs_hash_with_no_bktlock(hs))
939 if (cfs_hash_with_rw_bktlock(hs))
940 cfs_rwlock_init(&new_bkts[i]->hsb_lock.rw);
941 else if (cfs_hash_with_spin_bktlock(hs))
942 cfs_spin_lock_init(&new_bkts[i]->hsb_lock.spin);
944 LBUG(); /* invalid use-case */
950 * Initialize new libcfs hash, where:
951 * @name - Descriptive hash name
952 * @cur_bits - Initial hash table size, in bits
953 * @max_bits - Maximum allowed hash table resize, in bits
954 * @ops - Registered hash table operations
955 * @flags - CFS_HASH_REHASH enable synamic hash resizing
956 * - CFS_HASH_SORT enable chained hash sort
958 static int cfs_hash_rehash_worker(cfs_workitem_t *wi);
960 #if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1
961 static int cfs_hash_dep_print(cfs_workitem_t *wi)
963 cfs_hash_t *hs = container_of(wi, cfs_hash_t, hs_dep_wi);
969 cfs_spin_lock(&hs->hs_dep_lock);
970 dep = hs->hs_dep_max;
971 bkt = hs->hs_dep_bkt;
972 off = hs->hs_dep_off;
973 bits = hs->hs_dep_bits;
974 cfs_spin_unlock(&hs->hs_dep_lock);
976 LCONSOLE_WARN("#### HASH %s (bits: %d): max depth %d at bucket %d/%d\n",
977 hs->hs_name, bits, dep, bkt, off);
978 cfs_spin_lock(&hs->hs_dep_lock);
979 hs->hs_dep_bits = 0; /* mark as workitem done */
980 cfs_spin_unlock(&hs->hs_dep_lock);
984 static void cfs_hash_depth_wi_init(cfs_hash_t *hs)
986 cfs_spin_lock_init(&hs->hs_dep_lock);
987 cfs_wi_init(&hs->hs_dep_wi, hs,
988 cfs_hash_dep_print, CFS_WI_SCHED_ANY);
991 static void cfs_hash_depth_wi_cancel(cfs_hash_t *hs)
993 if (cfs_wi_cancel(&hs->hs_dep_wi))
996 cfs_spin_lock(&hs->hs_dep_lock);
997 while (hs->hs_dep_bits != 0) {
998 cfs_spin_unlock(&hs->hs_dep_lock);
1000 cfs_spin_lock(&hs->hs_dep_lock);
1002 cfs_spin_unlock(&hs->hs_dep_lock);
1005 #else /* CFS_HASH_DEBUG_LEVEL < CFS_HASH_DEBUG_1 */
1007 static inline void cfs_hash_depth_wi_init(cfs_hash_t *hs) {}
1008 static inline void cfs_hash_depth_wi_cancel(cfs_hash_t *hs) {}
1010 #endif /* CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 */
1013 cfs_hash_create(char *name, unsigned cur_bits, unsigned max_bits,
1014 unsigned bkt_bits, unsigned extra_bytes,
1015 unsigned min_theta, unsigned max_theta,
1016 cfs_hash_ops_t *ops, unsigned flags)
1023 CLASSERT(CFS_HASH_THETA_BITS < 15);
1025 LASSERT(name != NULL);
1026 LASSERT(ops != NULL);
1027 LASSERT(ops->hs_key);
1028 LASSERT(ops->hs_hash);
1029 LASSERT(ops->hs_object);
1030 LASSERT(ops->hs_keycmp);
1031 LASSERT(ops->hs_get != NULL);
1032 LASSERT(ops->hs_put_locked != NULL);
1034 if ((flags & CFS_HASH_REHASH) != 0)
1035 flags |= CFS_HASH_COUNTER; /* must have counter */
1037 LASSERT(cur_bits > 0);
1038 LASSERT(cur_bits >= bkt_bits);
1039 LASSERT(max_bits >= cur_bits && max_bits < 31);
1040 LASSERT(ergo((flags & CFS_HASH_REHASH) == 0, cur_bits == max_bits));
1041 LASSERT(ergo((flags & CFS_HASH_REHASH) != 0,
1042 (flags & CFS_HASH_NO_LOCK) == 0));
1043 LASSERT(ergo((flags & CFS_HASH_REHASH_KEY) != 0,
1044 ops->hs_keycpy != NULL));
1046 len = (flags & CFS_HASH_BIGNAME) == 0 ?
1047 CFS_HASH_NAME_LEN : CFS_HASH_BIGNAME_LEN;
1048 LIBCFS_ALLOC(hs, offsetof(cfs_hash_t, hs_name[len]));
1052 strncpy(hs->hs_name, name, len);
1053 hs->hs_name[len - 1] = '\0';
1054 hs->hs_flags = flags;
1056 cfs_atomic_set(&hs->hs_refcount, 1);
1057 cfs_atomic_set(&hs->hs_count, 0);
1059 cfs_hash_lock_setup(hs);
1060 cfs_hash_hlist_setup(hs);
1062 hs->hs_cur_bits = (__u8)cur_bits;
1063 hs->hs_min_bits = (__u8)cur_bits;
1064 hs->hs_max_bits = (__u8)max_bits;
1065 hs->hs_bkt_bits = (__u8)bkt_bits;
1068 hs->hs_extra_bytes = extra_bytes;
1069 hs->hs_rehash_bits = 0;
1070 cfs_wi_init(&hs->hs_rehash_wi, hs,
1071 cfs_hash_rehash_worker, CFS_WI_SCHED_ANY);
1072 cfs_hash_depth_wi_init(hs);
1074 if (cfs_hash_with_rehash(hs))
1075 __cfs_hash_set_theta(hs, min_theta, max_theta);
1077 hs->hs_buckets = cfs_hash_buckets_realloc(hs, NULL, 0,
1079 if (hs->hs_buckets != NULL)
1082 LIBCFS_FREE(hs, offsetof(cfs_hash_t, hs_name[len]));
1085 CFS_EXPORT_SYMBOL(cfs_hash_create);
1088 * Cleanup libcfs hash @hs.
1091 cfs_hash_destroy(cfs_hash_t *hs)
1093 cfs_hlist_node_t *hnode;
1094 cfs_hlist_node_t *pos;
1099 LASSERT(hs != NULL);
1100 LASSERT(!cfs_hash_is_exiting(hs) &&
1101 !cfs_hash_is_iterating(hs));
1104 * prohibit further rehashes, don't need any lock because
1105 * I'm the only (last) one can change it.
1108 if (cfs_hash_with_rehash(hs))
1109 cfs_hash_rehash_cancel(hs);
1111 cfs_hash_depth_wi_cancel(hs);
1112 /* rehash should be done/canceled */
1113 LASSERT(hs->hs_buckets != NULL &&
1114 hs->hs_rehash_buckets == NULL);
1116 cfs_hash_for_each_bucket(hs, &bd, i) {
1117 cfs_hlist_head_t *hhead;
1119 LASSERT(bd.bd_bucket != NULL);
1120 /* no need to take this lock, just for consistent code */
1121 cfs_hash_bd_lock(hs, &bd, 1);
1123 cfs_hash_bd_for_each_hlist(hs, &bd, hhead) {
1124 cfs_hlist_for_each_safe(hnode, pos, hhead) {
1125 LASSERTF(!cfs_hash_with_assert_empty(hs),
1126 "hash %s bucket %u(%u) is not "
1127 " empty: %u items left\n",
1128 hs->hs_name, bd.bd_bucket->hsb_index,
1129 bd.bd_offset, bd.bd_bucket->hsb_count);
1130 /* can't assert key valicate, because we
1131 * can interrupt rehash */
1132 cfs_hash_bd_del_locked(hs, &bd, hnode);
1133 cfs_hash_exit(hs, hnode);
1136 LASSERT(bd.bd_bucket->hsb_count == 0);
1137 cfs_hash_bd_unlock(hs, &bd, 1);
1141 LASSERT(cfs_atomic_read(&hs->hs_count) == 0);
1143 cfs_hash_buckets_free(hs->hs_buckets, cfs_hash_bkt_size(hs),
1144 0, CFS_HASH_NBKT(hs));
1145 i = cfs_hash_with_bigname(hs) ?
1146 CFS_HASH_BIGNAME_LEN : CFS_HASH_NAME_LEN;
1147 LIBCFS_FREE(hs, offsetof(cfs_hash_t, hs_name[i]));
1152 cfs_hash_t *cfs_hash_getref(cfs_hash_t *hs)
1154 if (cfs_atomic_inc_not_zero(&hs->hs_refcount))
1158 CFS_EXPORT_SYMBOL(cfs_hash_getref);
1160 void cfs_hash_putref(cfs_hash_t *hs)
1162 if (cfs_atomic_dec_and_test(&hs->hs_refcount))
1163 cfs_hash_destroy(hs);
1165 CFS_EXPORT_SYMBOL(cfs_hash_putref);
1168 cfs_hash_rehash_bits(cfs_hash_t *hs)
1170 if (cfs_hash_with_no_lock(hs) ||
1171 !cfs_hash_with_rehash(hs))
1174 if (unlikely(cfs_hash_is_exiting(hs)))
1177 if (unlikely(cfs_hash_is_rehashing(hs)))
1180 if (unlikely(cfs_hash_is_iterating(hs)))
1183 /* XXX: need to handle case with max_theta != 2.0
1184 * and the case with min_theta != 0.5 */
1185 if ((hs->hs_cur_bits < hs->hs_max_bits) &&
1186 (__cfs_hash_theta(hs) > hs->hs_max_theta))
1187 return hs->hs_cur_bits + 1;
1189 if (!cfs_hash_with_shrink(hs))
1192 if ((hs->hs_cur_bits > hs->hs_min_bits) &&
1193 (__cfs_hash_theta(hs) < hs->hs_min_theta))
1194 return hs->hs_cur_bits - 1;
1200 * don't allow inline rehash if:
1201 * - user wants non-blocking change (add/del) on hash table
1202 * - too many elements
1205 cfs_hash_rehash_inline(cfs_hash_t *hs)
1207 return !cfs_hash_with_nblk_change(hs) &&
1208 cfs_atomic_read(&hs->hs_count) < CFS_HASH_LOOP_HOG;
1212 * Add item @hnode to libcfs hash @hs using @key. The registered
1213 * ops->hs_get function will be called when the item is added.
1216 cfs_hash_add(cfs_hash_t *hs, const void *key, cfs_hlist_node_t *hnode)
1221 LASSERT(cfs_hlist_unhashed(hnode));
1223 cfs_hash_lock(hs, 0);
1224 cfs_hash_bd_get_and_lock(hs, key, &bd, 1);
1226 cfs_hash_key_validate(hs, key, hnode);
1227 cfs_hash_bd_add_locked(hs, &bd, hnode);
1229 cfs_hash_bd_unlock(hs, &bd, 1);
1231 bits = cfs_hash_rehash_bits(hs);
1232 cfs_hash_unlock(hs, 0);
1234 cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs));
1236 CFS_EXPORT_SYMBOL(cfs_hash_add);
1238 static cfs_hlist_node_t *
1239 cfs_hash_find_or_add(cfs_hash_t *hs, const void *key,
1240 cfs_hlist_node_t *hnode, int noref)
1242 cfs_hlist_node_t *ehnode;
1243 cfs_hash_bd_t bds[2];
1246 LASSERT(cfs_hlist_unhashed(hnode));
1248 cfs_hash_lock(hs, 0);
1249 cfs_hash_dual_bd_get_and_lock(hs, key, bds, 1);
1251 cfs_hash_key_validate(hs, key, hnode);
1252 ehnode = cfs_hash_dual_bd_findadd_locked(hs, bds, key,
1254 cfs_hash_dual_bd_unlock(hs, bds, 1);
1256 if (ehnode == hnode) /* new item added */
1257 bits = cfs_hash_rehash_bits(hs);
1258 cfs_hash_unlock(hs, 0);
1260 cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs));
1266 * Add item @hnode to libcfs hash @hs using @key. The registered
1267 * ops->hs_get function will be called if the item was added.
1268 * Returns 0 on success or -EALREADY on key collisions.
1271 cfs_hash_add_unique(cfs_hash_t *hs, const void *key, cfs_hlist_node_t *hnode)
1273 return cfs_hash_find_or_add(hs, key, hnode, 1) != hnode ?
1276 CFS_EXPORT_SYMBOL(cfs_hash_add_unique);
1279 * Add item @hnode to libcfs hash @hs using @key. If this @key
1280 * already exists in the hash then ops->hs_get will be called on the
1281 * conflicting entry and that entry will be returned to the caller.
1282 * Otherwise ops->hs_get is called on the item which was added.
1285 cfs_hash_findadd_unique(cfs_hash_t *hs, const void *key,
1286 cfs_hlist_node_t *hnode)
1288 hnode = cfs_hash_find_or_add(hs, key, hnode, 0);
1290 return cfs_hash_object(hs, hnode);
1292 CFS_EXPORT_SYMBOL(cfs_hash_findadd_unique);
1295 * Delete item @hnode from the libcfs hash @hs using @key. The @key
1296 * is required to ensure the correct hash bucket is locked since there
1297 * is no direct linkage from the item to the bucket. The object
1298 * removed from the hash will be returned and obs->hs_put is called
1299 * on the removed object.
1302 cfs_hash_del(cfs_hash_t *hs, const void *key, cfs_hlist_node_t *hnode)
1306 cfs_hash_bd_t bds[2];
1308 cfs_hash_lock(hs, 0);
1309 cfs_hash_dual_bd_get_and_lock(hs, key, bds, 1);
1311 if (bds[1].bd_bucket == NULL && hnode != NULL)
1312 cfs_hash_bd_del_locked(hs, &bds[0], hnode);
1314 hnode = cfs_hash_dual_bd_finddel_locked(hs, bds, key, hnode);
1316 if (hnode != NULL) {
1317 obj = cfs_hash_object(hs, hnode);
1318 bits = cfs_hash_rehash_bits(hs);
1321 cfs_hash_dual_bd_unlock(hs, bds, 1);
1322 cfs_hash_unlock(hs, 0);
1324 cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs));
1328 CFS_EXPORT_SYMBOL(cfs_hash_del);
1331 * Delete item given @key in libcfs hash @hs. The first @key found in
1332 * the hash will be removed, if the key exists multiple times in the hash
1333 * @hs this function must be called once per key. The removed object
1334 * will be returned and ops->hs_put is called on the removed object.
1337 cfs_hash_del_key(cfs_hash_t *hs, const void *key)
1339 return cfs_hash_del(hs, key, NULL);
1341 CFS_EXPORT_SYMBOL(cfs_hash_del_key);
1344 * Lookup an item using @key in the libcfs hash @hs and return it.
1345 * If the @key is found in the hash hs->hs_get() is called and the
1346 * matching objects is returned. It is the callers responsibility
1347 * to call the counterpart ops->hs_put using the cfs_hash_put() macro
1348 * when when finished with the object. If the @key was not found
1349 * in the hash @hs NULL is returned.
1352 cfs_hash_lookup(cfs_hash_t *hs, const void *key)
1355 cfs_hlist_node_t *hnode;
1356 cfs_hash_bd_t bds[2];
1358 cfs_hash_lock(hs, 0);
1359 cfs_hash_dual_bd_get_and_lock(hs, key, bds, 0);
1361 hnode = cfs_hash_dual_bd_lookup_locked(hs, bds, key);
1363 obj = cfs_hash_object(hs, hnode);
1365 cfs_hash_dual_bd_unlock(hs, bds, 0);
1366 cfs_hash_unlock(hs, 0);
1370 CFS_EXPORT_SYMBOL(cfs_hash_lookup);
1373 cfs_hash_for_each_enter(cfs_hash_t *hs)
1375 LASSERT(!cfs_hash_is_exiting(hs));
1377 if (!cfs_hash_with_rehash(hs))
1380 * NB: it's race on cfs_has_t::hs_iterating, but doesn't matter
1381 * because it's just an unreliable signal to rehash-thread,
1382 * rehash-thread will try to finsih rehash ASAP when seeing this.
1384 hs->hs_iterating = 1;
1386 cfs_hash_lock(hs, 1);
1389 /* NB: iteration is mostly called by service thread,
1390 * we tend to cancel pending rehash-requst, instead of
1391 * blocking service thread, we will relaunch rehash request
1392 * after iteration */
1393 if (cfs_hash_is_rehashing(hs))
1394 cfs_hash_rehash_cancel_locked(hs);
1395 cfs_hash_unlock(hs, 1);
1399 cfs_hash_for_each_exit(cfs_hash_t *hs)
1404 if (!cfs_hash_with_rehash(hs))
1406 cfs_hash_lock(hs, 1);
1407 remained = --hs->hs_iterators;
1408 bits = cfs_hash_rehash_bits(hs);
1409 cfs_hash_unlock(hs, 1);
1410 /* NB: it's race on cfs_has_t::hs_iterating, see above */
1412 hs->hs_iterating = 0;
1414 cfs_hash_rehash(hs, cfs_atomic_read(&hs->hs_count) <
1420 * For each item in the libcfs hash @hs call the passed callback @func
1421 * and pass to it as an argument each hash item and the private @data.
1423 * a) the function may sleep!
1424 * b) during the callback:
1425 * . the bucket lock is held so the callback must never sleep.
1426 * . if @removal_safe is true, use can remove current item by
1427 * cfs_hash_bd_del_locked
1430 cfs_hash_for_each_tight(cfs_hash_t *hs, cfs_hash_for_each_cb_t func,
1431 void *data, int remove_safe)
1433 cfs_hlist_node_t *hnode;
1434 cfs_hlist_node_t *pos;
1437 int excl = !!remove_safe;
1442 cfs_hash_for_each_enter(hs);
1444 cfs_hash_lock(hs, 0);
1445 LASSERT(!cfs_hash_is_rehashing(hs));
1447 cfs_hash_for_each_bucket(hs, &bd, i) {
1448 cfs_hlist_head_t *hhead;
1450 cfs_hash_bd_lock(hs, &bd, excl);
1451 if (func == NULL) { /* only glimpse size */
1452 count += bd.bd_bucket->hsb_count;
1453 cfs_hash_bd_unlock(hs, &bd, excl);
1457 cfs_hash_bd_for_each_hlist(hs, &bd, hhead) {
1458 cfs_hlist_for_each_safe(hnode, pos, hhead) {
1459 cfs_hash_bucket_validate(hs, &bd, hnode);
1462 if (func(hs, &bd, hnode, data)) {
1463 cfs_hash_bd_unlock(hs, &bd, excl);
1468 cfs_hash_bd_unlock(hs, &bd, excl);
1469 if (loop < CFS_HASH_LOOP_HOG)
1472 cfs_hash_unlock(hs, 0);
1474 cfs_hash_lock(hs, 0);
1477 cfs_hash_unlock(hs, 0);
1479 cfs_hash_for_each_exit(hs);
1484 cfs_hash_cond_opt_cb_t func;
1486 } cfs_hash_cond_arg_t;
1489 cfs_hash_cond_del_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
1490 cfs_hlist_node_t *hnode, void *data)
1492 cfs_hash_cond_arg_t *cond = data;
1494 if (cond->func(cfs_hash_object(hs, hnode), cond->arg))
1495 cfs_hash_bd_del_locked(hs, bd, hnode);
1500 * Delete item from the libcfs hash @hs when @func return true.
1501 * The write lock being hold during loop for each bucket to avoid
1502 * any object be reference.
1505 cfs_hash_cond_del(cfs_hash_t *hs, cfs_hash_cond_opt_cb_t func, void *data)
1507 cfs_hash_cond_arg_t arg = {
1512 cfs_hash_for_each_tight(hs, cfs_hash_cond_del_locked, &arg, 1);
1514 CFS_EXPORT_SYMBOL(cfs_hash_cond_del);
1517 cfs_hash_for_each(cfs_hash_t *hs,
1518 cfs_hash_for_each_cb_t func, void *data)
1520 cfs_hash_for_each_tight(hs, func, data, 0);
1522 CFS_EXPORT_SYMBOL(cfs_hash_for_each);
1525 cfs_hash_for_each_safe(cfs_hash_t *hs,
1526 cfs_hash_for_each_cb_t func, void *data)
1528 cfs_hash_for_each_tight(hs, func, data, 1);
1530 CFS_EXPORT_SYMBOL(cfs_hash_for_each_safe);
1533 cfs_hash_peek(cfs_hash_t *hs, cfs_hash_bd_t *bd,
1534 cfs_hlist_node_t *hnode, void *data)
1537 return 1; /* return 1 to break the loop */
1541 cfs_hash_is_empty(cfs_hash_t *hs)
1545 cfs_hash_for_each_tight(hs, cfs_hash_peek, &empty, 0);
1548 CFS_EXPORT_SYMBOL(cfs_hash_is_empty);
1551 cfs_hash_size_get(cfs_hash_t *hs)
1553 return cfs_hash_with_counter(hs) ?
1554 cfs_atomic_read(&hs->hs_count) :
1555 cfs_hash_for_each_tight(hs, NULL, NULL, 0);
1557 CFS_EXPORT_SYMBOL(cfs_hash_size_get);
1560 * cfs_hash_for_each_relax:
1561 * Iterate the hash table and call @func on each item without
1562 * any lock. This function can't guarantee to finish iteration
1563 * if these features are enabled:
1565 * a. if rehash_key is enabled, an item can be moved from
1566 * one bucket to another bucket
1567 * b. user can remove non-zero-ref item from hash-table,
1568 * so the item can be removed from hash-table, even worse,
1569 * it's possible that user changed key and insert to another
1571 * there's no way for us to finish iteration correctly on previous
1572 * two cases, so iteration has to be stopped on change.
1575 cfs_hash_for_each_relax(cfs_hash_t *hs, cfs_hash_for_each_cb_t func, void *data)
1577 cfs_hlist_node_t *hnode;
1578 cfs_hlist_node_t *tmp;
1587 stop_on_change = cfs_hash_with_rehash_key(hs) ||
1588 !cfs_hash_with_no_itemref(hs) ||
1589 CFS_HOP(hs, put_locked) == NULL;
1590 cfs_hash_lock(hs, 0);
1591 LASSERT(!cfs_hash_is_rehashing(hs));
1593 cfs_hash_for_each_bucket(hs, &bd, i) {
1594 cfs_hlist_head_t *hhead;
1596 cfs_hash_bd_lock(hs, &bd, 0);
1597 version = cfs_hash_bd_version_get(&bd);
1599 cfs_hash_bd_for_each_hlist(hs, &bd, hhead) {
1600 for (hnode = hhead->first; hnode != NULL;) {
1601 cfs_hash_bucket_validate(hs, &bd, hnode);
1602 cfs_hash_get(hs, hnode);
1603 cfs_hash_bd_unlock(hs, &bd, 0);
1604 cfs_hash_unlock(hs, 0);
1606 rc = func(hs, &bd, hnode, data);
1608 cfs_hash_put(hs, hnode);
1612 cfs_hash_lock(hs, 0);
1613 cfs_hash_bd_lock(hs, &bd, 0);
1614 if (!stop_on_change) {
1616 cfs_hash_put_locked(hs, hnode);
1618 } else { /* bucket changed? */
1620 cfs_hash_bd_version_get(&bd))
1622 /* safe to continue because no change */
1623 hnode = hnode->next;
1625 if (rc) /* callback wants to break iteration */
1629 cfs_hash_bd_unlock(hs, &bd, 0);
1631 cfs_hash_unlock(hs, 0);
1637 cfs_hash_for_each_nolock(cfs_hash_t *hs,
1638 cfs_hash_for_each_cb_t func, void *data)
1642 if (cfs_hash_with_no_lock(hs) ||
1643 cfs_hash_with_rehash_key(hs) ||
1644 !cfs_hash_with_no_itemref(hs))
1645 RETURN(-EOPNOTSUPP);
1647 if (CFS_HOP(hs, get) == NULL ||
1648 (CFS_HOP(hs, put) == NULL &&
1649 CFS_HOP(hs, put_locked) == NULL))
1650 RETURN(-EOPNOTSUPP);
1652 cfs_hash_for_each_enter(hs);
1653 cfs_hash_for_each_relax(hs, func, data);
1654 cfs_hash_for_each_exit(hs);
1658 CFS_EXPORT_SYMBOL(cfs_hash_for_each_nolock);
1661 * For each hash bucket in the libcfs hash @hs call the passed callback
1662 * @func until all the hash buckets are empty. The passed callback @func
1663 * or the previously registered callback hs->hs_put must remove the item
1664 * from the hash. You may either use the cfs_hash_del() or hlist_del()
1665 * functions. No rwlocks will be held during the callback @func it is
1666 * safe to sleep if needed. This function will not terminate until the
1667 * hash is empty. Note it is still possible to concurrently add new
1668 * items in to the hash. It is the callers responsibility to ensure
1669 * the required locking is in place to prevent concurrent insertions.
1672 cfs_hash_for_each_empty(cfs_hash_t *hs,
1673 cfs_hash_for_each_cb_t func, void *data)
1678 if (cfs_hash_with_no_lock(hs))
1681 if (CFS_HOP(hs, get) == NULL ||
1682 (CFS_HOP(hs, put) == NULL &&
1683 CFS_HOP(hs, put_locked) == NULL))
1686 cfs_hash_for_each_enter(hs);
1687 while (cfs_hash_for_each_relax(hs, func, data)) {
1688 CDEBUG(D_INFO, "Try to empty hash: %s, loop: %u\n",
1691 cfs_hash_for_each_exit(hs);
1694 CFS_EXPORT_SYMBOL(cfs_hash_for_each_empty);
1697 cfs_hash_hlist_for_each(cfs_hash_t *hs, unsigned hindex,
1698 cfs_hash_for_each_cb_t func, void *data)
1700 cfs_hlist_head_t *hhead;
1701 cfs_hlist_node_t *hnode;
1704 cfs_hash_for_each_enter(hs);
1705 cfs_hash_lock(hs, 0);
1706 if (hindex >= CFS_HASH_NHLIST(hs))
1709 cfs_hash_bd_index_set(hs, hindex, &bd);
1711 cfs_hash_bd_lock(hs, &bd, 0);
1712 hhead = cfs_hash_bd_hhead(hs, &bd);
1713 cfs_hlist_for_each(hnode, hhead) {
1714 if (func(hs, &bd, hnode, data))
1717 cfs_hash_bd_unlock(hs, &bd, 0);
1719 cfs_hash_unlock(hs, 0);
1720 cfs_hash_for_each_exit(hs);
1723 CFS_EXPORT_SYMBOL(cfs_hash_hlist_for_each);
1726 * For each item in the libcfs hash @hs which matches the @key call
1727 * the passed callback @func and pass to it as an argument each hash
1728 * item and the private @data. During the callback the bucket lock
1729 * is held so the callback must never sleep.
1732 cfs_hash_for_each_key(cfs_hash_t *hs, const void *key,
1733 cfs_hash_for_each_cb_t func, void *data)
1735 cfs_hlist_node_t *hnode;
1736 cfs_hash_bd_t bds[2];
1739 cfs_hash_lock(hs, 0);
1741 cfs_hash_dual_bd_get_and_lock(hs, key, bds, 0);
1743 cfs_hash_for_each_bd(bds, 2, i) {
1744 cfs_hlist_head_t *hlist = cfs_hash_bd_hhead(hs, &bds[i]);
1746 cfs_hlist_for_each(hnode, hlist) {
1747 cfs_hash_bucket_validate(hs, &bds[i], hnode);
1749 if (cfs_hash_keycmp(hs, key, hnode)) {
1750 if (func(hs, &bds[i], hnode, data))
1756 cfs_hash_dual_bd_unlock(hs, bds, 0);
1757 cfs_hash_unlock(hs, 0);
1759 CFS_EXPORT_SYMBOL(cfs_hash_for_each_key);
1762 * Rehash the libcfs hash @hs to the given @bits. This can be used
1763 * to grow the hash size when excessive chaining is detected, or to
1764 * shrink the hash when it is larger than needed. When the CFS_HASH_REHASH
1765 * flag is set in @hs the libcfs hash may be dynamically rehashed
1766 * during addition or removal if the hash's theta value exceeds
1767 * either the hs->hs_min_theta or hs->max_theta values. By default
1768 * these values are tuned to keep the chained hash depth small, and
1769 * this approach assumes a reasonably uniform hashing function. The
1770 * theta thresholds for @hs are tunable via cfs_hash_set_theta().
1773 cfs_hash_rehash_cancel_locked(cfs_hash_t *hs)
1777 /* need hold cfs_hash_lock(hs, 1) */
1778 LASSERT(cfs_hash_with_rehash(hs) &&
1779 !cfs_hash_with_no_lock(hs));
1781 if (!cfs_hash_is_rehashing(hs))
1784 if (cfs_wi_cancel(&hs->hs_rehash_wi)) {
1785 hs->hs_rehash_bits = 0;
1789 for (i = 2; cfs_hash_is_rehashing(hs); i++) {
1790 cfs_hash_unlock(hs, 1);
1791 /* raise console warning while waiting too long */
1792 CDEBUG(IS_PO2(i >> 3) ? D_WARNING : D_INFO,
1793 "hash %s is still rehashing, rescheded %d\n",
1794 hs->hs_name, i - 1);
1796 cfs_hash_lock(hs, 1);
1799 CFS_EXPORT_SYMBOL(cfs_hash_rehash_cancel_locked);
1802 cfs_hash_rehash_cancel(cfs_hash_t *hs)
1804 cfs_hash_lock(hs, 1);
1805 cfs_hash_rehash_cancel_locked(hs);
1806 cfs_hash_unlock(hs, 1);
1808 CFS_EXPORT_SYMBOL(cfs_hash_rehash_cancel);
1811 cfs_hash_rehash(cfs_hash_t *hs, int do_rehash)
1815 LASSERT(cfs_hash_with_rehash(hs) && !cfs_hash_with_no_lock(hs));
1817 cfs_hash_lock(hs, 1);
1819 rc = cfs_hash_rehash_bits(hs);
1821 cfs_hash_unlock(hs, 1);
1825 hs->hs_rehash_bits = rc;
1827 /* launch and return */
1828 cfs_wi_schedule(&hs->hs_rehash_wi);
1829 cfs_hash_unlock(hs, 1);
1833 /* rehash right now */
1834 cfs_hash_unlock(hs, 1);
1836 return cfs_hash_rehash_worker(&hs->hs_rehash_wi);
1838 CFS_EXPORT_SYMBOL(cfs_hash_rehash);
1841 cfs_hash_rehash_bd(cfs_hash_t *hs, cfs_hash_bd_t *old)
1844 cfs_hlist_head_t *hhead;
1845 cfs_hlist_node_t *hnode;
1846 cfs_hlist_node_t *pos;
1850 /* hold cfs_hash_lock(hs, 1), so don't need any bucket lock */
1851 cfs_hash_bd_for_each_hlist(hs, old, hhead) {
1852 cfs_hlist_for_each_safe(hnode, pos, hhead) {
1853 key = cfs_hash_key(hs, hnode);
1854 LASSERT(key != NULL);
1855 /* Validate hnode is in the correct bucket. */
1856 cfs_hash_bucket_validate(hs, old, hnode);
1858 * Delete from old hash bucket; move to new bucket.
1859 * ops->hs_key must be defined.
1861 cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets,
1862 hs->hs_rehash_bits, key, &new);
1863 cfs_hash_bd_move_locked(hs, old, &new, hnode);
1872 cfs_hash_rehash_worker(cfs_workitem_t *wi)
1874 cfs_hash_t *hs = container_of(wi, cfs_hash_t, hs_rehash_wi);
1875 cfs_hash_bucket_t **bkts;
1877 unsigned int old_size;
1878 unsigned int new_size;
1884 LASSERT (hs != NULL && cfs_hash_with_rehash(hs));
1886 cfs_hash_lock(hs, 0);
1887 LASSERT(cfs_hash_is_rehashing(hs));
1889 old_size = CFS_HASH_NBKT(hs);
1890 new_size = CFS_HASH_RH_NBKT(hs);
1892 cfs_hash_unlock(hs, 0);
1895 * don't need hs::hs_rwlock for hs::hs_buckets,
1896 * because nobody can change bkt-table except me.
1898 bkts = cfs_hash_buckets_realloc(hs, hs->hs_buckets,
1899 old_size, new_size);
1900 cfs_hash_lock(hs, 1);
1906 if (bkts == hs->hs_buckets) {
1907 bkts = NULL; /* do nothing */
1911 rc = __cfs_hash_theta(hs);
1912 if ((rc >= hs->hs_min_theta) && (rc <= hs->hs_max_theta)) {
1913 /* free the new allocated bkt-table */
1914 old_size = new_size;
1915 new_size = CFS_HASH_NBKT(hs);
1920 LASSERT(hs->hs_rehash_buckets == NULL);
1921 hs->hs_rehash_buckets = bkts;
1924 cfs_hash_for_each_bucket(hs, &bd, i) {
1925 if (cfs_hash_is_exiting(hs)) {
1927 /* someone wants to destroy the hash, abort now */
1928 if (old_size < new_size) /* OK to free old bkt-table */
1930 /* it's shrinking, need free new bkt-table */
1931 hs->hs_rehash_buckets = NULL;
1932 old_size = new_size;
1933 new_size = CFS_HASH_NBKT(hs);
1937 count += cfs_hash_rehash_bd(hs, &bd);
1938 if (count < CFS_HASH_LOOP_HOG ||
1939 cfs_hash_is_iterating(hs)) { /* need to finish ASAP */
1944 cfs_hash_unlock(hs, 1);
1946 cfs_hash_lock(hs, 1);
1949 hs->hs_rehash_count++;
1951 bkts = hs->hs_buckets;
1952 hs->hs_buckets = hs->hs_rehash_buckets;
1953 hs->hs_rehash_buckets = NULL;
1955 hs->hs_cur_bits = hs->hs_rehash_bits;
1957 hs->hs_rehash_bits = 0;
1959 cfs_wi_exit(wi); /* never be scheduled again */
1960 bsize = cfs_hash_bkt_size(hs);
1961 cfs_hash_unlock(hs, 1);
1962 /* can't refer to @hs anymore because it could be destroyed */
1964 cfs_hash_buckets_free(bkts, bsize, new_size, old_size);
1966 CDEBUG(D_INFO, "early quit of of rehashing: %d\n", rc);
1967 /* cfs_workitem require us to always return 0 */
1972 * Rehash the object referenced by @hnode in the libcfs hash @hs. The
1973 * @old_key must be provided to locate the objects previous location
1974 * in the hash, and the @new_key will be used to reinsert the object.
1975 * Use this function instead of a cfs_hash_add() + cfs_hash_del()
1976 * combo when it is critical that there is no window in time where the
1977 * object is missing from the hash. When an object is being rehashed
1978 * the registered cfs_hash_get() and cfs_hash_put() functions will
1981 void cfs_hash_rehash_key(cfs_hash_t *hs, const void *old_key,
1982 void *new_key, cfs_hlist_node_t *hnode)
1984 cfs_hash_bd_t bds[3];
1985 cfs_hash_bd_t old_bds[2];
1986 cfs_hash_bd_t new_bd;
1988 LASSERT(!cfs_hlist_unhashed(hnode));
1990 cfs_hash_lock(hs, 0);
1992 cfs_hash_dual_bd_get(hs, old_key, old_bds);
1993 cfs_hash_bd_get(hs, new_key, &new_bd);
1995 bds[0] = old_bds[0];
1996 bds[1] = old_bds[1];
1999 /* NB: bds[0] and bds[1] are ordered already */
2000 cfs_hash_bd_order(&bds[1], &bds[2]);
2001 cfs_hash_bd_order(&bds[0], &bds[1]);
2003 cfs_hash_multi_bd_lock(hs, bds, 3, 1);
2004 if (likely(old_bds[1].bd_bucket == NULL)) {
2005 cfs_hash_bd_move_locked(hs, &old_bds[0], &new_bd, hnode);
2007 cfs_hash_dual_bd_finddel_locked(hs, old_bds, old_key, hnode);
2008 cfs_hash_bd_add_locked(hs, &new_bd, hnode);
2010 /* overwrite key inside locks, otherwise may screw up with
2011 * other operations, i.e: rehash */
2012 cfs_hash_keycpy(hs, new_key, hnode);
2014 cfs_hash_multi_bd_unlock(hs, bds, 3, 1);
2015 cfs_hash_unlock(hs, 0);
2017 CFS_EXPORT_SYMBOL(cfs_hash_rehash_key);
2019 int cfs_hash_debug_header(char *str, int size)
2021 return snprintf(str, size, "%-*s%6s%6s%6s%6s%6s%6s%6s%7s%8s%8s%8s%s\n",
2022 CFS_HASH_BIGNAME_LEN,
2023 "name", "cur", "min", "max", "theta", "t-min", "t-max",
2024 "flags", "rehash", "count", "maxdep", "maxdepb",
2027 CFS_EXPORT_SYMBOL(cfs_hash_debug_header);
2029 static cfs_hash_bucket_t **
2030 cfs_hash_full_bkts(cfs_hash_t *hs)
2032 /* NB: caller should hold hs->hs_rwlock if REHASH is set */
2033 if (hs->hs_rehash_buckets == NULL)
2034 return hs->hs_buckets;
2036 LASSERT(hs->hs_rehash_bits != 0);
2037 return hs->hs_rehash_bits > hs->hs_cur_bits ?
2038 hs->hs_rehash_buckets : hs->hs_buckets;
2042 cfs_hash_full_nbkt(cfs_hash_t *hs)
2044 /* NB: caller should hold hs->hs_rwlock if REHASH is set */
2045 if (hs->hs_rehash_buckets == NULL)
2046 return CFS_HASH_NBKT(hs);
2048 LASSERT(hs->hs_rehash_bits != 0);
2049 return hs->hs_rehash_bits > hs->hs_cur_bits ?
2050 CFS_HASH_RH_NBKT(hs) : CFS_HASH_NBKT(hs);
2053 int cfs_hash_debug_str(cfs_hash_t *hs, char *str, int size)
2055 int dist[8] = { 0, };
2063 if (str == NULL || size == 0)
2066 cfs_hash_lock(hs, 0);
2067 theta = __cfs_hash_theta(hs);
2069 c += snprintf(str + c, size - c, "%-*s ",
2070 CFS_HASH_BIGNAME_LEN, hs->hs_name);
2071 c += snprintf(str + c, size - c, "%5d ", 1 << hs->hs_cur_bits);
2072 c += snprintf(str + c, size - c, "%5d ", 1 << hs->hs_min_bits);
2073 c += snprintf(str + c, size - c, "%5d ", 1 << hs->hs_max_bits);
2074 c += snprintf(str + c, size - c, "%d.%03d ",
2075 __cfs_hash_theta_int(theta),
2076 __cfs_hash_theta_frac(theta));
2077 c += snprintf(str + c, size - c, "%d.%03d ",
2078 __cfs_hash_theta_int(hs->hs_min_theta),
2079 __cfs_hash_theta_frac(hs->hs_min_theta));
2080 c += snprintf(str + c, size - c, "%d.%03d ",
2081 __cfs_hash_theta_int(hs->hs_max_theta),
2082 __cfs_hash_theta_frac(hs->hs_max_theta));
2083 c += snprintf(str + c, size - c, " 0x%02x ", hs->hs_flags);
2084 c += snprintf(str + c, size - c, "%6d ", hs->hs_rehash_count);
2087 * The distribution is a summary of the chained hash depth in
2088 * each of the libcfs hash buckets. Each buckets hsb_count is
2089 * divided by the hash theta value and used to generate a
2090 * histogram of the hash distribution. A uniform hash will
2091 * result in all hash buckets being close to the average thus
2092 * only the first few entries in the histogram will be non-zero.
2093 * If you hash function results in a non-uniform hash the will
2094 * be observable by outlier bucks in the distribution histogram.
2096 * Uniform hash distribution: 128/128/0/0/0/0/0/0
2097 * Non-Uniform hash distribution: 128/125/0/0/0/0/2/1
2099 for (i = 0; i < cfs_hash_full_nbkt(hs); i++) {
2102 bd.bd_bucket = cfs_hash_full_bkts(hs)[i];
2103 cfs_hash_bd_lock(hs, &bd, 0);
2104 if (maxdep < bd.bd_bucket->hsb_depmax) {
2105 maxdep = bd.bd_bucket->hsb_depmax;
2107 maxdepb = cfs_ffz(~maxdep);
2110 total += bd.bd_bucket->hsb_count;
2111 dist[min(__cfs_fls(bd.bd_bucket->hsb_count/max(theta,1)),7)]++;
2112 cfs_hash_bd_unlock(hs, &bd, 0);
2115 c += snprintf(str + c, size - c, "%7d ", total);
2116 c += snprintf(str + c, size - c, "%7d ", maxdep);
2117 c += snprintf(str + c, size - c, "%7d ", maxdepb);
2118 for (i = 0; i < 8; i++)
2119 c += snprintf(str + c, size - c, "%d%c", dist[i],
2120 (i == 7) ? '\n' : '/');
2122 cfs_hash_unlock(hs, 0);
2126 CFS_EXPORT_SYMBOL(cfs_hash_debug_str);