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.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
36 * libcfs/libcfs/hash.c
38 * Implement a hash class for hash process in lustre system.
40 * Author: YuZhangyong <yzy@clusterfs.com>
42 * 2008-08-15: Brian Behlendorf <behlendorf1@llnl.gov>
43 * - Simplified API and improved documentation
44 * - Added per-hash feature flags:
45 * * CFS_HASH_DEBUG additional validation
46 * * CFS_HASH_REHASH dynamic rehashing
47 * - Added per-hash statistics
48 * - General performance enhancements
50 * 2009-07-31: Liang Zhen <zhen.liang@sun.com>
51 * - move all stuff to libcfs
52 * - don't allow cur_bits != max_bits without setting of CFS_HASH_REHASH
53 * - ignore hs_rwlock if without CFS_HASH_REHASH setting
54 * - buckets are allocated one by one(intead of contiguous memory),
55 * to avoid unnecessary cacheline conflict
57 * 2010-03-01: Liang Zhen <zhen.liang@sun.com>
58 * - "bucket" is a group of hlist_head now, user can speicify bucket size
59 * by bkt_bits of cfs_hash_create(), all hlist_heads in a bucket share
60 * one lock for reducing memory overhead.
62 * - support lockless hash, caller will take care of locks:
63 * avoid lock overhead for hash tables that are already protected
64 * by locking in the caller for another reason
66 * - support both spin_lock/rwlock for bucket:
67 * overhead of spinlock contention is lower than read/write
68 * contention of rwlock, so using spinlock to serialize operations on
69 * bucket is more reasonable for those frequently changed hash tables
71 * - support one-single lock mode:
72 * one lock to protect all hash operations to avoid overhead of
73 * multiple locks if hash table is always small
75 * - removed a lot of unnecessary addref & decref on hash element:
76 * addref & decref are atomic operations in many use-cases which
79 * - support non-blocking cfs_hash_add() and cfs_hash_findadd():
80 * some lustre use-cases require these functions to be strictly
81 * non-blocking, we need to schedule required rehash on a different
82 * thread on those cases.
84 * - safer rehash on large hash table
85 * In old implementation, rehash function will exclusively lock the
86 * hash table and finish rehash in one batch, it's dangerous on SMP
87 * system because rehash millions of elements could take long time.
88 * New implemented rehash can release lock and relax CPU in middle
89 * of rehash, it's safe for another thread to search/change on the
90 * hash table even it's in rehasing.
92 * - support two different refcount modes
93 * . hash table has refcount on element
94 * . hash table doesn't change refcount on adding/removing element
96 * - support long name hash table (for param-tree)
98 * - fix a bug for cfs_hash_rehash_key:
99 * in old implementation, cfs_hash_rehash_key could screw up the
100 * hash-table because @key is overwritten without any protection.
101 * Now we need user to define hs_keycpy for those rehash enabled
102 * hash tables, cfs_hash_rehash_key will overwrite hash-key
103 * inside lock by calling hs_keycpy.
105 * - better hash iteration:
106 * Now we support both locked iteration & lockless iteration of hash
107 * table. Also, user can break the iteration by return 1 in callback.
110 #include <libcfs/libcfs.h>
112 #if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1
113 static unsigned int warn_on_depth = 0;
114 CFS_MODULE_PARM(warn_on_depth, "i", uint, 0644,
115 "warning when hash depth is high.");
119 cfs_hash_nl_lock(cfs_hash_lock_t *lock, int exclusive) {}
122 cfs_hash_nl_unlock(cfs_hash_lock_t *lock, int exclusive) {}
125 cfs_hash_spin_lock(cfs_hash_lock_t *lock, int exclusive)
127 cfs_spin_lock(&lock->spin);
131 cfs_hash_spin_unlock(cfs_hash_lock_t *lock, int exclusive)
133 cfs_spin_unlock(&lock->spin);
137 cfs_hash_rw_lock(cfs_hash_lock_t *lock, int exclusive)
140 cfs_read_lock(&lock->rw);
142 cfs_write_lock(&lock->rw);
146 cfs_hash_rw_unlock(cfs_hash_lock_t *lock, int exclusive)
149 cfs_read_unlock(&lock->rw);
151 cfs_write_unlock(&lock->rw);
155 static cfs_hash_lock_ops_t cfs_hash_nl_lops =
157 .hs_lock = cfs_hash_nl_lock,
158 .hs_unlock = cfs_hash_nl_unlock,
159 .hs_bkt_lock = cfs_hash_nl_lock,
160 .hs_bkt_unlock = cfs_hash_nl_unlock,
163 /** no bucket lock, one spinlock to protect everything */
164 static cfs_hash_lock_ops_t cfs_hash_nbl_lops =
166 .hs_lock = cfs_hash_spin_lock,
167 .hs_unlock = cfs_hash_spin_unlock,
168 .hs_bkt_lock = cfs_hash_nl_lock,
169 .hs_bkt_unlock = cfs_hash_nl_unlock,
172 /** spin bucket lock, rehash is enabled */
173 static cfs_hash_lock_ops_t cfs_hash_bkt_spin_lops =
175 .hs_lock = cfs_hash_rw_lock,
176 .hs_unlock = cfs_hash_rw_unlock,
177 .hs_bkt_lock = cfs_hash_spin_lock,
178 .hs_bkt_unlock = cfs_hash_spin_unlock,
181 /** rw bucket lock, rehash is enabled */
182 static cfs_hash_lock_ops_t cfs_hash_bkt_rw_lops =
184 .hs_lock = cfs_hash_rw_lock,
185 .hs_unlock = cfs_hash_rw_unlock,
186 .hs_bkt_lock = cfs_hash_rw_lock,
187 .hs_bkt_unlock = cfs_hash_rw_unlock,
190 /** spin bucket lock, rehash is disabled */
191 static cfs_hash_lock_ops_t cfs_hash_nr_bkt_spin_lops =
193 .hs_lock = cfs_hash_nl_lock,
194 .hs_unlock = cfs_hash_nl_unlock,
195 .hs_bkt_lock = cfs_hash_spin_lock,
196 .hs_bkt_unlock = cfs_hash_spin_unlock,
199 /** rw bucket lock, rehash is disabled */
200 static cfs_hash_lock_ops_t cfs_hash_nr_bkt_rw_lops =
202 .hs_lock = cfs_hash_nl_lock,
203 .hs_unlock = cfs_hash_nl_unlock,
204 .hs_bkt_lock = cfs_hash_rw_lock,
205 .hs_bkt_unlock = cfs_hash_rw_unlock,
209 cfs_hash_lock_setup(cfs_hash_t *hs)
211 if (cfs_hash_with_no_lock(hs)) {
212 hs->hs_lops = &cfs_hash_nl_lops;
214 } else if (cfs_hash_with_no_bktlock(hs)) {
215 hs->hs_lops = &cfs_hash_nbl_lops;
216 cfs_spin_lock_init(&hs->hs_lock.spin);
218 } else if (cfs_hash_with_rehash(hs)) {
219 cfs_rwlock_init(&hs->hs_lock.rw);
221 if (cfs_hash_with_rw_bktlock(hs))
222 hs->hs_lops = &cfs_hash_bkt_rw_lops;
223 else if (cfs_hash_with_spin_bktlock(hs))
224 hs->hs_lops = &cfs_hash_bkt_spin_lops;
228 if (cfs_hash_with_rw_bktlock(hs))
229 hs->hs_lops = &cfs_hash_nr_bkt_rw_lops;
230 else if (cfs_hash_with_spin_bktlock(hs))
231 hs->hs_lops = &cfs_hash_nr_bkt_spin_lops;
238 * Simple hash head without depth tracking
239 * new element is always added to head of hlist
242 cfs_hlist_head_t hh_head; /**< entries list */
246 cfs_hash_hh_hhead_size(cfs_hash_t *hs)
248 return sizeof(cfs_hash_head_t);
251 static cfs_hlist_head_t *
252 cfs_hash_hh_hhead(cfs_hash_t *hs, cfs_hash_bd_t *bd)
254 cfs_hash_head_t *head = (cfs_hash_head_t *)&bd->bd_bucket->hsb_head[0];
256 return &head[bd->bd_offset].hh_head;
260 cfs_hash_hh_hnode_add(cfs_hash_t *hs, cfs_hash_bd_t *bd,
261 cfs_hlist_node_t *hnode)
263 cfs_hlist_add_head(hnode, cfs_hash_hh_hhead(hs, bd));
264 return -1; /* unknown depth */
268 cfs_hash_hh_hnode_del(cfs_hash_t *hs, cfs_hash_bd_t *bd,
269 cfs_hlist_node_t *hnode)
271 cfs_hlist_del_init(hnode);
272 return -1; /* unknown depth */
276 * Simple hash head with depth tracking
277 * new element is always added to head of hlist
280 cfs_hlist_head_t hd_head; /**< entries list */
281 unsigned int hd_depth; /**< list length */
282 } cfs_hash_head_dep_t;
285 cfs_hash_hd_hhead_size(cfs_hash_t *hs)
287 return sizeof(cfs_hash_head_dep_t);
290 static cfs_hlist_head_t *
291 cfs_hash_hd_hhead(cfs_hash_t *hs, cfs_hash_bd_t *bd)
293 cfs_hash_head_dep_t *head;
295 head = (cfs_hash_head_dep_t *)&bd->bd_bucket->hsb_head[0];
296 return &head[bd->bd_offset].hd_head;
300 cfs_hash_hd_hnode_add(cfs_hash_t *hs, cfs_hash_bd_t *bd,
301 cfs_hlist_node_t *hnode)
303 cfs_hash_head_dep_t *hh = container_of(cfs_hash_hd_hhead(hs, bd),
304 cfs_hash_head_dep_t, hd_head);
305 cfs_hlist_add_head(hnode, &hh->hd_head);
306 return ++hh->hd_depth;
310 cfs_hash_hd_hnode_del(cfs_hash_t *hs, cfs_hash_bd_t *bd,
311 cfs_hlist_node_t *hnode)
313 cfs_hash_head_dep_t *hh = container_of(cfs_hash_hd_hhead(hs, bd),
314 cfs_hash_head_dep_t, hd_head);
315 cfs_hlist_del_init(hnode);
316 return --hh->hd_depth;
320 * double links hash head without depth tracking
321 * new element is always added to tail of hlist
324 cfs_hlist_head_t dh_head; /**< entries list */
325 cfs_hlist_node_t *dh_tail; /**< the last entry */
329 cfs_hash_dh_hhead_size(cfs_hash_t *hs)
331 return sizeof(cfs_hash_dhead_t);
334 static cfs_hlist_head_t *
335 cfs_hash_dh_hhead(cfs_hash_t *hs, cfs_hash_bd_t *bd)
337 cfs_hash_dhead_t *head;
339 head = (cfs_hash_dhead_t *)&bd->bd_bucket->hsb_head[0];
340 return &head[bd->bd_offset].dh_head;
344 cfs_hash_dh_hnode_add(cfs_hash_t *hs, cfs_hash_bd_t *bd,
345 cfs_hlist_node_t *hnode)
347 cfs_hash_dhead_t *dh = container_of(cfs_hash_dh_hhead(hs, bd),
348 cfs_hash_dhead_t, dh_head);
350 if (dh->dh_tail != NULL) /* not empty */
351 cfs_hlist_add_after(dh->dh_tail, hnode);
352 else /* empty list */
353 cfs_hlist_add_head(hnode, &dh->dh_head);
355 return -1; /* unknown depth */
359 cfs_hash_dh_hnode_del(cfs_hash_t *hs, cfs_hash_bd_t *bd,
360 cfs_hlist_node_t *hnd)
362 cfs_hash_dhead_t *dh = container_of(cfs_hash_dh_hhead(hs, bd),
363 cfs_hash_dhead_t, dh_head);
365 if (hnd->next == NULL) { /* it's the tail */
366 dh->dh_tail = (hnd->pprev == &dh->dh_head.first) ? NULL :
367 container_of(hnd->pprev, cfs_hlist_node_t, next);
369 cfs_hlist_del_init(hnd);
370 return -1; /* unknown depth */
374 * double links hash head with depth tracking
375 * new element is always added to tail of hlist
378 cfs_hlist_head_t dd_head; /**< entries list */
379 cfs_hlist_node_t *dd_tail; /**< the last entry */
380 unsigned int dd_depth; /**< list length */
381 } cfs_hash_dhead_dep_t;
384 cfs_hash_dd_hhead_size(cfs_hash_t *hs)
386 return sizeof(cfs_hash_dhead_dep_t);
389 static cfs_hlist_head_t *
390 cfs_hash_dd_hhead(cfs_hash_t *hs, cfs_hash_bd_t *bd)
392 cfs_hash_dhead_dep_t *head;
394 head = (cfs_hash_dhead_dep_t *)&bd->bd_bucket->hsb_head[0];
395 return &head[bd->bd_offset].dd_head;
399 cfs_hash_dd_hnode_add(cfs_hash_t *hs, cfs_hash_bd_t *bd,
400 cfs_hlist_node_t *hnode)
402 cfs_hash_dhead_dep_t *dh = container_of(cfs_hash_dd_hhead(hs, bd),
403 cfs_hash_dhead_dep_t, dd_head);
405 if (dh->dd_tail != NULL) /* not empty */
406 cfs_hlist_add_after(dh->dd_tail, hnode);
407 else /* empty list */
408 cfs_hlist_add_head(hnode, &dh->dd_head);
410 return ++dh->dd_depth;
414 cfs_hash_dd_hnode_del(cfs_hash_t *hs, cfs_hash_bd_t *bd,
415 cfs_hlist_node_t *hnd)
417 cfs_hash_dhead_dep_t *dh = container_of(cfs_hash_dd_hhead(hs, bd),
418 cfs_hash_dhead_dep_t, dd_head);
420 if (hnd->next == NULL) { /* it's the tail */
421 dh->dd_tail = (hnd->pprev == &dh->dd_head.first) ? NULL :
422 container_of(hnd->pprev, cfs_hlist_node_t, next);
424 cfs_hlist_del_init(hnd);
425 return --dh->dd_depth;
428 static cfs_hash_hlist_ops_t cfs_hash_hh_hops = {
429 .hop_hhead = cfs_hash_hh_hhead,
430 .hop_hhead_size = cfs_hash_hh_hhead_size,
431 .hop_hnode_add = cfs_hash_hh_hnode_add,
432 .hop_hnode_del = cfs_hash_hh_hnode_del,
435 static cfs_hash_hlist_ops_t cfs_hash_hd_hops = {
436 .hop_hhead = cfs_hash_hd_hhead,
437 .hop_hhead_size = cfs_hash_hd_hhead_size,
438 .hop_hnode_add = cfs_hash_hd_hnode_add,
439 .hop_hnode_del = cfs_hash_hd_hnode_del,
442 static cfs_hash_hlist_ops_t cfs_hash_dh_hops = {
443 .hop_hhead = cfs_hash_dh_hhead,
444 .hop_hhead_size = cfs_hash_dh_hhead_size,
445 .hop_hnode_add = cfs_hash_dh_hnode_add,
446 .hop_hnode_del = cfs_hash_dh_hnode_del,
449 static cfs_hash_hlist_ops_t cfs_hash_dd_hops = {
450 .hop_hhead = cfs_hash_dd_hhead,
451 .hop_hhead_size = cfs_hash_dd_hhead_size,
452 .hop_hnode_add = cfs_hash_dd_hnode_add,
453 .hop_hnode_del = cfs_hash_dd_hnode_del,
457 cfs_hash_hlist_setup(cfs_hash_t *hs)
459 if (cfs_hash_with_add_tail(hs)) {
460 hs->hs_hops = cfs_hash_with_depth(hs) ?
461 &cfs_hash_dd_hops : &cfs_hash_dh_hops;
463 hs->hs_hops = cfs_hash_with_depth(hs) ?
464 &cfs_hash_hd_hops : &cfs_hash_hh_hops;
469 cfs_hash_bd_from_key(cfs_hash_t *hs, cfs_hash_bucket_t **bkts,
470 unsigned int bits, void *key, cfs_hash_bd_t *bd)
472 unsigned int index = cfs_hash_id(hs, key, (1U << bits) - 1);
474 LASSERT(bits == hs->hs_cur_bits || bits == hs->hs_rehash_bits);
476 bd->bd_bucket = bkts[index & ((1U << (bits - hs->hs_bkt_bits)) - 1)];
477 bd->bd_offset = index >> (bits - hs->hs_bkt_bits);
481 cfs_hash_bd_get(cfs_hash_t *hs, void *key, cfs_hash_bd_t *bd)
483 /* NB: caller should hold hs->hs_rwlock if REHASH is set */
484 if (likely(hs->hs_rehash_buckets == NULL)) {
485 cfs_hash_bd_from_key(hs, hs->hs_buckets,
486 hs->hs_cur_bits, key, bd);
488 LASSERT(hs->hs_rehash_bits != 0);
489 cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets,
490 hs->hs_rehash_bits, key, bd);
493 CFS_EXPORT_SYMBOL(cfs_hash_bd_get);
496 cfs_hash_bd_dep_record(cfs_hash_t *hs, cfs_hash_bd_t *bd, int dep_cur)
498 if (likely(dep_cur <= bd->bd_bucket->hsb_depmax))
501 bd->bd_bucket->hsb_depmax = dep_cur;
502 # if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1
503 if (likely(warn_on_depth == 0 ||
504 max(warn_on_depth, hs->hs_dep_max) >= dep_cur))
507 cfs_spin_lock(&hs->hs_dep_lock);
508 hs->hs_dep_max = dep_cur;
509 hs->hs_dep_bkt = bd->bd_bucket->hsb_index;
510 hs->hs_dep_off = bd->bd_offset;
511 hs->hs_dep_bits = hs->hs_cur_bits;
512 cfs_spin_unlock(&hs->hs_dep_lock);
514 cfs_wi_schedule(&hs->hs_dep_wi);
519 cfs_hash_bd_add_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
520 cfs_hlist_node_t *hnode)
524 rc = hs->hs_hops->hop_hnode_add(hs, bd, hnode);
525 cfs_hash_bd_dep_record(hs, bd, rc);
526 bd->bd_bucket->hsb_version++;
527 if (unlikely(bd->bd_bucket->hsb_version == 0))
528 bd->bd_bucket->hsb_version++;
529 bd->bd_bucket->hsb_count++;
531 if (cfs_hash_with_counter(hs))
532 cfs_atomic_inc(&hs->hs_count);
533 if (!cfs_hash_with_no_itemref(hs))
534 cfs_hash_get(hs, hnode);
536 CFS_EXPORT_SYMBOL(cfs_hash_bd_add_locked);
539 cfs_hash_bd_del_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
540 cfs_hlist_node_t *hnode)
542 hs->hs_hops->hop_hnode_del(hs, bd, hnode);
544 LASSERT(bd->bd_bucket->hsb_count > 0);
545 bd->bd_bucket->hsb_count--;
546 bd->bd_bucket->hsb_version++;
547 if (unlikely(bd->bd_bucket->hsb_version == 0))
548 bd->bd_bucket->hsb_version++;
550 if (cfs_hash_with_counter(hs)) {
551 LASSERT(cfs_atomic_read(&hs->hs_count) > 0);
552 cfs_atomic_dec(&hs->hs_count);
554 if (!cfs_hash_with_no_itemref(hs))
555 cfs_hash_put_locked(hs, hnode);
557 CFS_EXPORT_SYMBOL(cfs_hash_bd_del_locked);
560 cfs_hash_bd_move_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd_old,
561 cfs_hash_bd_t *bd_new, cfs_hlist_node_t *hnode)
563 cfs_hash_bucket_t *obkt = bd_old->bd_bucket;
564 cfs_hash_bucket_t *nbkt = bd_new->bd_bucket;
567 if (cfs_hash_bd_compare(bd_old, bd_new) == 0)
570 /* use cfs_hash_bd_hnode_add/del, to avoid atomic & refcount ops
571 * in cfs_hash_bd_del/add_locked */
572 hs->hs_hops->hop_hnode_del(hs, bd_old, hnode);
573 rc = hs->hs_hops->hop_hnode_add(hs, bd_new, hnode);
574 cfs_hash_bd_dep_record(hs, bd_new, rc);
576 LASSERT(obkt->hsb_count > 0);
579 if (unlikely(obkt->hsb_version == 0))
583 if (unlikely(nbkt->hsb_version == 0))
586 CFS_EXPORT_SYMBOL(cfs_hash_bd_move_locked);
589 /** always set, for sanity (avoid ZERO intent) */
590 CFS_HS_LOOKUP_MASK_FIND = 1 << 0,
591 /** return entry with a ref */
592 CFS_HS_LOOKUP_MASK_REF = 1 << 1,
593 /** add entry if not existing */
594 CFS_HS_LOOKUP_MASK_ADD = 1 << 2,
595 /** delete entry, ignore other masks */
596 CFS_HS_LOOKUP_MASK_DEL = 1 << 3,
599 typedef enum cfs_hash_lookup_intent {
600 /** return item w/o refcount */
601 CFS_HS_LOOKUP_IT_PEEK = CFS_HS_LOOKUP_MASK_FIND,
602 /** return item with refcount */
603 CFS_HS_LOOKUP_IT_FIND = (CFS_HS_LOOKUP_MASK_FIND |
604 CFS_HS_LOOKUP_MASK_REF),
605 /** return item w/o refcount if existed, otherwise add */
606 CFS_HS_LOOKUP_IT_ADD = (CFS_HS_LOOKUP_MASK_FIND |
607 CFS_HS_LOOKUP_MASK_ADD),
608 /** return item with refcount if existed, otherwise add */
609 CFS_HS_LOOKUP_IT_FINDADD = (CFS_HS_LOOKUP_IT_FIND |
610 CFS_HS_LOOKUP_MASK_ADD),
611 /** delete if existed */
612 CFS_HS_LOOKUP_IT_FINDDEL = (CFS_HS_LOOKUP_MASK_FIND |
613 CFS_HS_LOOKUP_MASK_DEL)
614 } cfs_hash_lookup_intent_t;
616 static cfs_hlist_node_t *
617 cfs_hash_bd_lookup_intent(cfs_hash_t *hs, cfs_hash_bd_t *bd,
618 void *key, cfs_hlist_node_t *hnode,
619 cfs_hash_lookup_intent_t intent)
622 cfs_hlist_head_t *hhead = cfs_hash_bd_hhead(hs, bd);
623 cfs_hlist_node_t *ehnode;
624 cfs_hlist_node_t *match;
625 int intent_add = (intent & CFS_HS_LOOKUP_MASK_ADD) != 0;
627 /* with this function, we can avoid a lot of useless refcount ops,
628 * which are expensive atomic operations most time. */
629 match = intent_add ? NULL : hnode;
630 cfs_hlist_for_each(ehnode, hhead) {
631 if (!cfs_hash_keycmp(hs, key, ehnode))
634 if (match != NULL && match != ehnode) /* can't match */
638 if ((intent & CFS_HS_LOOKUP_MASK_DEL) != 0) {
639 cfs_hash_bd_del_locked(hs, bd, ehnode);
643 /* caller wants refcount? */
644 if ((intent & CFS_HS_LOOKUP_MASK_REF) != 0)
645 cfs_hash_get(hs, ehnode);
652 LASSERT(hnode != NULL);
653 cfs_hash_bd_add_locked(hs, bd, hnode);
658 cfs_hash_bd_lookup_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd, void *key)
660 return cfs_hash_bd_lookup_intent(hs, bd, key, NULL,
661 CFS_HS_LOOKUP_IT_FIND);
663 CFS_EXPORT_SYMBOL(cfs_hash_bd_lookup_locked);
666 cfs_hash_bd_findadd_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
667 void *key, cfs_hlist_node_t *hnode,
670 return cfs_hash_bd_lookup_intent(hs, bd, key, hnode,
671 CFS_HS_LOOKUP_IT_ADD |
672 (!noref * CFS_HS_LOOKUP_MASK_REF));
674 CFS_EXPORT_SYMBOL(cfs_hash_bd_findadd_locked);
677 cfs_hash_bd_finddel_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
678 void *key, cfs_hlist_node_t *hnode)
680 /* hnode can be NULL, we find the first item with @key */
681 return cfs_hash_bd_lookup_intent(hs, bd, key, hnode,
682 CFS_HS_LOOKUP_IT_FINDDEL);
684 CFS_EXPORT_SYMBOL(cfs_hash_bd_finddel_locked);
687 cfs_hash_multi_bd_lock(cfs_hash_t *hs, cfs_hash_bd_t *bds,
688 unsigned n, int excl)
690 cfs_hash_bucket_t *prev = NULL;
694 * bds must be ascendantly ordered by bd->bd_bucket->hsb_index.
695 * NB: it's possible that several bds point to the same bucket but
696 * have different bd::bd_offset, so need take care of deadlock.
698 cfs_hash_for_each_bd(bds, n, i) {
699 if (prev == bds[i].bd_bucket)
702 LASSERT(prev == NULL ||
703 prev->hsb_index < bds[i].bd_bucket->hsb_index);
704 cfs_hash_bd_lock(hs, &bds[i], excl);
705 prev = bds[i].bd_bucket;
710 cfs_hash_multi_bd_unlock(cfs_hash_t *hs, cfs_hash_bd_t *bds,
711 unsigned n, int excl)
713 cfs_hash_bucket_t *prev = NULL;
716 cfs_hash_for_each_bd(bds, n, i) {
717 if (prev != bds[i].bd_bucket) {
718 cfs_hash_bd_unlock(hs, &bds[i], excl);
719 prev = bds[i].bd_bucket;
724 static cfs_hlist_node_t *
725 cfs_hash_multi_bd_lookup_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds,
726 unsigned n, void *key)
728 cfs_hlist_node_t *ehnode;
731 cfs_hash_for_each_bd(bds, n, i) {
732 ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, NULL,
733 CFS_HS_LOOKUP_IT_FIND);
740 static cfs_hlist_node_t *
741 cfs_hash_multi_bd_findadd_locked(cfs_hash_t *hs,
742 cfs_hash_bd_t *bds, unsigned n, void *key,
743 cfs_hlist_node_t *hnode, int noref)
745 cfs_hlist_node_t *ehnode;
749 LASSERT(hnode != NULL);
750 intent = CFS_HS_LOOKUP_IT_PEEK | (!noref * CFS_HS_LOOKUP_MASK_REF);
752 cfs_hash_for_each_bd(bds, n, i) {
753 ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key,
759 if (i == 1) { /* only one bucket */
760 cfs_hash_bd_add_locked(hs, &bds[0], hnode);
764 cfs_hash_bd_get(hs, key, &mybd);
765 cfs_hash_bd_add_locked(hs, &mybd, hnode);
771 static cfs_hlist_node_t *
772 cfs_hash_multi_bd_finddel_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds,
773 unsigned n, void *key, cfs_hlist_node_t *hnode)
775 cfs_hlist_node_t *ehnode;
778 cfs_hash_for_each_bd(bds, n, i) {
779 ehnode = cfs_hash_bd_lookup_intent(hs, &bds[i], key, hnode,
780 CFS_HS_LOOKUP_IT_FINDDEL);
788 cfs_hash_bd_order(cfs_hash_bd_t *bd1, cfs_hash_bd_t *bd2)
792 if (bd2->bd_bucket == NULL)
795 if (bd1->bd_bucket == NULL) {
797 bd2->bd_bucket = NULL;
801 rc = cfs_hash_bd_compare(bd1, bd2);
803 bd2->bd_bucket = NULL;
805 } else if (rc > 0) { /* swab bd1 and bd2 */
815 cfs_hash_dual_bd_get(cfs_hash_t *hs, void *key, cfs_hash_bd_t *bds)
817 /* NB: caller should hold hs_lock.rw if REHASH is set */
818 cfs_hash_bd_from_key(hs, hs->hs_buckets,
819 hs->hs_cur_bits, key, &bds[0]);
820 if (likely(hs->hs_rehash_buckets == NULL)) {
821 /* no rehash or not rehashing */
822 bds[1].bd_bucket = NULL;
826 LASSERT(hs->hs_rehash_bits != 0);
827 cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets,
828 hs->hs_rehash_bits, key, &bds[1]);
830 cfs_hash_bd_order(&bds[0], &bds[1]);
832 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_get);
835 cfs_hash_dual_bd_lock(cfs_hash_t *hs, cfs_hash_bd_t *bds, int excl)
837 cfs_hash_multi_bd_lock(hs, bds, 2, excl);
839 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_lock);
842 cfs_hash_dual_bd_unlock(cfs_hash_t *hs, cfs_hash_bd_t *bds, int excl)
844 cfs_hash_multi_bd_unlock(hs, bds, 2, excl);
846 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_unlock);
849 cfs_hash_dual_bd_lookup_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds, void *key)
851 return cfs_hash_multi_bd_lookup_locked(hs, bds, 2, key);
853 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_lookup_locked);
856 cfs_hash_dual_bd_findadd_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds,
857 void *key, cfs_hlist_node_t *hnode,
860 return cfs_hash_multi_bd_findadd_locked(hs, bds, 2, key,
863 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_findadd_locked);
866 cfs_hash_dual_bd_finddel_locked(cfs_hash_t *hs, cfs_hash_bd_t *bds,
867 void *key, cfs_hlist_node_t *hnode)
869 return cfs_hash_multi_bd_finddel_locked(hs, bds, 2, key, hnode);
871 CFS_EXPORT_SYMBOL(cfs_hash_dual_bd_finddel_locked);
874 cfs_hash_buckets_free(cfs_hash_bucket_t **buckets,
875 int bkt_size, int prev_size, int size)
879 for (i = prev_size; i < size; i++) {
880 if (buckets[i] != NULL)
881 LIBCFS_FREE(buckets[i], bkt_size);
884 LIBCFS_FREE(buckets, sizeof(buckets[0]) * size);
888 * Create or grow bucket memory. Return old_buckets if no allocation was
889 * needed, the newly allocated buckets if allocation was needed and
890 * successful, and NULL on error.
892 static cfs_hash_bucket_t **
893 cfs_hash_buckets_realloc(cfs_hash_t *hs, cfs_hash_bucket_t **old_bkts,
894 unsigned int old_size, unsigned int new_size)
896 cfs_hash_bucket_t **new_bkts;
899 LASSERT(old_size == 0 || old_bkts != NULL);
901 if (old_bkts != NULL && old_size == new_size)
904 LIBCFS_ALLOC(new_bkts, sizeof(new_bkts[0]) * new_size);
905 if (new_bkts == NULL)
908 if (old_bkts != NULL) {
909 memcpy(new_bkts, old_bkts,
910 min(old_size, new_size) * sizeof(*old_bkts));
913 for (i = old_size; i < new_size; i++) {
914 cfs_hlist_head_t *hhead;
917 LIBCFS_ALLOC(new_bkts[i], cfs_hash_bkt_size(hs));
918 if (new_bkts[i] == NULL) {
919 cfs_hash_buckets_free(new_bkts, cfs_hash_bkt_size(hs),
924 new_bkts[i]->hsb_index = i;
925 new_bkts[i]->hsb_version = 1; /* shouldn't be zero */
926 new_bkts[i]->hsb_depmax = -1; /* unknown */
927 bd.bd_bucket = new_bkts[i];
928 cfs_hash_bd_for_each_hlist(hs, &bd, hhead)
929 CFS_INIT_HLIST_HEAD(hhead);
931 if (cfs_hash_with_no_lock(hs) ||
932 cfs_hash_with_no_bktlock(hs))
935 if (cfs_hash_with_rw_bktlock(hs))
936 cfs_rwlock_init(&new_bkts[i]->hsb_lock.rw);
937 else if (cfs_hash_with_spin_bktlock(hs))
938 cfs_spin_lock_init(&new_bkts[i]->hsb_lock.spin);
940 LBUG(); /* invalid use-case */
946 * Initialize new libcfs hash, where:
947 * @name - Descriptive hash name
948 * @cur_bits - Initial hash table size, in bits
949 * @max_bits - Maximum allowed hash table resize, in bits
950 * @ops - Registered hash table operations
951 * @flags - CFS_HASH_REHASH enable synamic hash resizing
952 * - CFS_HASH_SORT enable chained hash sort
954 static int cfs_hash_rehash_worker(cfs_workitem_t *wi);
956 #if CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1
957 static int cfs_hash_dep_print(cfs_workitem_t *wi)
959 cfs_hash_t *hs = container_of(wi, cfs_hash_t, hs_dep_wi);
965 cfs_spin_lock(&hs->hs_dep_lock);
966 dep = hs->hs_dep_max;
967 bkt = hs->hs_dep_bkt;
968 off = hs->hs_dep_off;
969 bits = hs->hs_dep_bits;
970 cfs_spin_unlock(&hs->hs_dep_lock);
972 LCONSOLE_WARN("#### HASH %s (bits: %d): max depth %d at bucket %d/%d\n",
973 hs->hs_name, bits, dep, bkt, off);
974 cfs_spin_lock(&hs->hs_dep_lock);
975 hs->hs_dep_bits = 0; /* mark as workitem done */
976 cfs_spin_unlock(&hs->hs_dep_lock);
980 static void cfs_hash_depth_wi_init(cfs_hash_t *hs)
982 cfs_spin_lock_init(&hs->hs_dep_lock);
983 cfs_wi_init(&hs->hs_dep_wi, hs,
984 cfs_hash_dep_print, CFS_WI_SCHED_ANY);
987 static void cfs_hash_depth_wi_cancel(cfs_hash_t *hs)
989 if (cfs_wi_cancel(&hs->hs_dep_wi))
992 cfs_spin_lock(&hs->hs_dep_lock);
993 while (hs->hs_dep_bits != 0) {
994 cfs_spin_unlock(&hs->hs_dep_lock);
996 cfs_spin_lock(&hs->hs_dep_lock);
998 cfs_spin_unlock(&hs->hs_dep_lock);
1001 #else /* CFS_HASH_DEBUG_LEVEL < CFS_HASH_DEBUG_1 */
1003 static inline void cfs_hash_depth_wi_init(cfs_hash_t *hs) {}
1004 static inline void cfs_hash_depth_wi_cancel(cfs_hash_t *hs) {}
1006 #endif /* CFS_HASH_DEBUG_LEVEL >= CFS_HASH_DEBUG_1 */
1009 cfs_hash_create(char *name, unsigned cur_bits, unsigned max_bits,
1010 unsigned bkt_bits, unsigned extra_bytes,
1011 unsigned min_theta, unsigned max_theta,
1012 cfs_hash_ops_t *ops, unsigned flags)
1019 CLASSERT(CFS_HASH_THETA_BITS < 15);
1021 LASSERT(name != NULL);
1022 LASSERT(ops != NULL);
1023 LASSERT(ops->hs_key);
1024 LASSERT(ops->hs_hash);
1025 LASSERT(ops->hs_object);
1026 LASSERT(ops->hs_keycmp);
1027 LASSERT(ops->hs_get != NULL);
1028 LASSERT(ops->hs_put_locked != NULL);
1030 if ((flags & CFS_HASH_REHASH) != 0)
1031 flags |= CFS_HASH_COUNTER; /* must have counter */
1033 LASSERT(cur_bits > 0);
1034 LASSERT(cur_bits >= bkt_bits);
1035 LASSERT(max_bits >= cur_bits && max_bits < 31);
1036 LASSERT(ergo((flags & CFS_HASH_REHASH) == 0, cur_bits == max_bits));
1037 LASSERT(ergo((flags & CFS_HASH_REHASH) != 0,
1038 (flags & CFS_HASH_NO_LOCK) == 0));
1039 LASSERT(ergo((flags & CFS_HASH_REHASH_KEY) != 0,
1040 ops->hs_keycpy != NULL));
1042 len = (flags & CFS_HASH_BIGNAME) == 0 ?
1043 CFS_HASH_NAME_LEN : CFS_HASH_BIGNAME_LEN;
1044 LIBCFS_ALLOC(hs, offsetof(cfs_hash_t, hs_name[len]));
1048 strncpy(hs->hs_name, name, len);
1049 hs->hs_name[len - 1] = '\0';
1050 hs->hs_flags = flags;
1052 cfs_atomic_set(&hs->hs_refcount, 1);
1053 cfs_atomic_set(&hs->hs_count, 0);
1055 cfs_hash_lock_setup(hs);
1056 cfs_hash_hlist_setup(hs);
1058 hs->hs_cur_bits = (__u8)cur_bits;
1059 hs->hs_min_bits = (__u8)cur_bits;
1060 hs->hs_max_bits = (__u8)max_bits;
1061 hs->hs_bkt_bits = (__u8)bkt_bits;
1064 hs->hs_extra_bytes = extra_bytes;
1065 hs->hs_rehash_bits = 0;
1066 cfs_wi_init(&hs->hs_rehash_wi, hs,
1067 cfs_hash_rehash_worker, CFS_WI_SCHED_ANY);
1068 cfs_hash_depth_wi_init(hs);
1070 if (cfs_hash_with_rehash(hs))
1071 __cfs_hash_set_theta(hs, min_theta, max_theta);
1073 hs->hs_buckets = cfs_hash_buckets_realloc(hs, NULL, 0,
1075 if (hs->hs_buckets != NULL)
1078 LIBCFS_FREE(hs, offsetof(cfs_hash_t, hs_name[len]));
1081 CFS_EXPORT_SYMBOL(cfs_hash_create);
1084 * Cleanup libcfs hash @hs.
1087 cfs_hash_destroy(cfs_hash_t *hs)
1089 cfs_hlist_node_t *hnode;
1090 cfs_hlist_node_t *pos;
1095 LASSERT(hs != NULL);
1096 LASSERT(!cfs_hash_is_exiting(hs) &&
1097 !cfs_hash_is_iterating(hs));
1100 * prohibit further rehashes, don't need any lock because
1101 * I'm the only (last) one can change it.
1104 if (cfs_hash_with_rehash(hs))
1105 cfs_hash_rehash_cancel(hs);
1107 cfs_hash_depth_wi_cancel(hs);
1108 /* rehash should be done/canceled */
1109 LASSERT(hs->hs_buckets != NULL &&
1110 hs->hs_rehash_buckets == NULL);
1112 cfs_hash_for_each_bucket(hs, &bd, i) {
1113 cfs_hlist_head_t *hhead;
1115 LASSERT(bd.bd_bucket != NULL);
1116 /* no need to take this lock, just for consistent code */
1117 cfs_hash_bd_lock(hs, &bd, 1);
1119 cfs_hash_bd_for_each_hlist(hs, &bd, hhead) {
1120 cfs_hlist_for_each_safe(hnode, pos, hhead) {
1121 LASSERTF(!cfs_hash_with_assert_empty(hs),
1122 "hash %s bucket %u(%u) is not "
1123 " empty: %u items left\n",
1124 hs->hs_name, bd.bd_bucket->hsb_index,
1125 bd.bd_offset, bd.bd_bucket->hsb_count);
1126 /* can't assert key valicate, because we
1127 * can interrupt rehash */
1128 cfs_hash_bd_del_locked(hs, &bd, hnode);
1129 cfs_hash_exit(hs, hnode);
1132 LASSERT(bd.bd_bucket->hsb_count == 0);
1133 cfs_hash_bd_unlock(hs, &bd, 1);
1137 LASSERT(cfs_atomic_read(&hs->hs_count) == 0);
1139 cfs_hash_buckets_free(hs->hs_buckets, cfs_hash_bkt_size(hs),
1140 0, CFS_HASH_NBKT(hs));
1141 i = cfs_hash_with_bigname(hs) ?
1142 CFS_HASH_BIGNAME_LEN : CFS_HASH_NAME_LEN;
1143 LIBCFS_FREE(hs, offsetof(cfs_hash_t, hs_name[i]));
1148 cfs_hash_t *cfs_hash_getref(cfs_hash_t *hs)
1150 if (cfs_atomic_inc_not_zero(&hs->hs_refcount))
1154 CFS_EXPORT_SYMBOL(cfs_hash_getref);
1156 void cfs_hash_putref(cfs_hash_t *hs)
1158 if (cfs_atomic_dec_and_test(&hs->hs_refcount))
1159 cfs_hash_destroy(hs);
1161 CFS_EXPORT_SYMBOL(cfs_hash_putref);
1164 cfs_hash_rehash_bits(cfs_hash_t *hs)
1166 if (cfs_hash_with_no_lock(hs) ||
1167 !cfs_hash_with_rehash(hs))
1170 if (unlikely(cfs_hash_is_exiting(hs)))
1173 if (unlikely(cfs_hash_is_rehashing(hs)))
1176 if (unlikely(cfs_hash_is_iterating(hs)))
1179 /* XXX: need to handle case with max_theta != 2.0
1180 * and the case with min_theta != 0.5 */
1181 if ((hs->hs_cur_bits < hs->hs_max_bits) &&
1182 (__cfs_hash_theta(hs) > hs->hs_max_theta))
1183 return hs->hs_cur_bits + 1;
1185 if (!cfs_hash_with_shrink(hs))
1188 if ((hs->hs_cur_bits > hs->hs_min_bits) &&
1189 (__cfs_hash_theta(hs) < hs->hs_min_theta))
1190 return hs->hs_cur_bits - 1;
1196 * don't allow inline rehash if:
1197 * - user wants non-blocking change (add/del) on hash table
1198 * - too many elements
1201 cfs_hash_rehash_inline(cfs_hash_t *hs)
1203 return !cfs_hash_with_nblk_change(hs) &&
1204 cfs_atomic_read(&hs->hs_count) < CFS_HASH_LOOP_HOG;
1208 * Add item @hnode to libcfs hash @hs using @key. The registered
1209 * ops->hs_get function will be called when the item is added.
1212 cfs_hash_add(cfs_hash_t *hs, void *key, cfs_hlist_node_t *hnode)
1217 LASSERT(cfs_hlist_unhashed(hnode));
1219 cfs_hash_lock(hs, 0);
1220 cfs_hash_bd_get_and_lock(hs, key, &bd, 1);
1222 cfs_hash_key_validate(hs, key, hnode);
1223 cfs_hash_bd_add_locked(hs, &bd, hnode);
1225 cfs_hash_bd_unlock(hs, &bd, 1);
1227 bits = cfs_hash_rehash_bits(hs);
1228 cfs_hash_unlock(hs, 0);
1230 cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs));
1232 CFS_EXPORT_SYMBOL(cfs_hash_add);
1234 static cfs_hlist_node_t *
1235 cfs_hash_find_or_add(cfs_hash_t *hs, void *key,
1236 cfs_hlist_node_t *hnode, int noref)
1238 cfs_hlist_node_t *ehnode;
1239 cfs_hash_bd_t bds[2];
1242 LASSERT(cfs_hlist_unhashed(hnode));
1244 cfs_hash_lock(hs, 0);
1245 cfs_hash_dual_bd_get_and_lock(hs, key, bds, 1);
1247 cfs_hash_key_validate(hs, key, hnode);
1248 ehnode = cfs_hash_dual_bd_findadd_locked(hs, bds, key,
1250 cfs_hash_dual_bd_unlock(hs, bds, 1);
1252 if (ehnode == hnode) /* new item added */
1253 bits = cfs_hash_rehash_bits(hs);
1254 cfs_hash_unlock(hs, 0);
1256 cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs));
1262 * Add item @hnode to libcfs hash @hs using @key. The registered
1263 * ops->hs_get function will be called if the item was added.
1264 * Returns 0 on success or -EALREADY on key collisions.
1267 cfs_hash_add_unique(cfs_hash_t *hs, void *key, cfs_hlist_node_t *hnode)
1269 return cfs_hash_find_or_add(hs, key, hnode, 1) != hnode ?
1272 CFS_EXPORT_SYMBOL(cfs_hash_add_unique);
1275 * Add item @hnode to libcfs hash @hs using @key. If this @key
1276 * already exists in the hash then ops->hs_get will be called on the
1277 * conflicting entry and that entry will be returned to the caller.
1278 * Otherwise ops->hs_get is called on the item which was added.
1281 cfs_hash_findadd_unique(cfs_hash_t *hs, void *key,
1282 cfs_hlist_node_t *hnode)
1284 hnode = cfs_hash_find_or_add(hs, key, hnode, 0);
1286 return cfs_hash_object(hs, hnode);
1288 CFS_EXPORT_SYMBOL(cfs_hash_findadd_unique);
1291 * Delete item @hnode from the libcfs hash @hs using @key. The @key
1292 * is required to ensure the correct hash bucket is locked since there
1293 * is no direct linkage from the item to the bucket. The object
1294 * removed from the hash will be returned and obs->hs_put is called
1295 * on the removed object.
1298 cfs_hash_del(cfs_hash_t *hs, void *key, cfs_hlist_node_t *hnode)
1302 cfs_hash_bd_t bds[2];
1304 cfs_hash_lock(hs, 0);
1305 cfs_hash_dual_bd_get_and_lock(hs, key, bds, 1);
1307 if (bds[1].bd_bucket == NULL && hnode != NULL)
1308 cfs_hash_bd_del_locked(hs, &bds[0], hnode);
1310 hnode = cfs_hash_dual_bd_finddel_locked(hs, bds, key, hnode);
1312 if (hnode != NULL) {
1313 obj = cfs_hash_object(hs, hnode);
1314 bits = cfs_hash_rehash_bits(hs);
1317 cfs_hash_dual_bd_unlock(hs, bds, 1);
1318 cfs_hash_unlock(hs, 0);
1320 cfs_hash_rehash(hs, cfs_hash_rehash_inline(hs));
1324 CFS_EXPORT_SYMBOL(cfs_hash_del);
1327 * Delete item given @key in libcfs hash @hs. The first @key found in
1328 * the hash will be removed, if the key exists multiple times in the hash
1329 * @hs this function must be called once per key. The removed object
1330 * will be returned and ops->hs_put is called on the removed object.
1333 cfs_hash_del_key(cfs_hash_t *hs, void *key)
1335 return cfs_hash_del(hs, key, NULL);
1337 CFS_EXPORT_SYMBOL(cfs_hash_del_key);
1340 * Lookup an item using @key in the libcfs hash @hs and return it.
1341 * If the @key is found in the hash hs->hs_get() is called and the
1342 * matching objects is returned. It is the callers responsibility
1343 * to call the counterpart ops->hs_put using the cfs_hash_put() macro
1344 * when when finished with the object. If the @key was not found
1345 * in the hash @hs NULL is returned.
1348 cfs_hash_lookup(cfs_hash_t *hs, void *key)
1351 cfs_hlist_node_t *hnode;
1352 cfs_hash_bd_t bds[2];
1354 cfs_hash_lock(hs, 0);
1355 cfs_hash_dual_bd_get_and_lock(hs, key, bds, 0);
1357 hnode = cfs_hash_dual_bd_lookup_locked(hs, bds, key);
1359 obj = cfs_hash_object(hs, hnode);
1361 cfs_hash_dual_bd_unlock(hs, bds, 0);
1362 cfs_hash_unlock(hs, 0);
1366 CFS_EXPORT_SYMBOL(cfs_hash_lookup);
1369 cfs_hash_for_each_enter(cfs_hash_t *hs)
1371 LASSERT(!cfs_hash_is_exiting(hs));
1373 if (!cfs_hash_with_rehash(hs))
1376 * NB: it's race on cfs_has_t::hs_iterating, but doesn't matter
1377 * because it's just an unreliable signal to rehash-thread,
1378 * rehash-thread will try to finsih rehash ASAP when seeing this.
1380 hs->hs_iterating = 1;
1382 cfs_hash_lock(hs, 1);
1385 /* NB: iteration is mostly called by service thread,
1386 * we tend to cancel pending rehash-requst, instead of
1387 * blocking service thread, we will relaunch rehash request
1388 * after iteration */
1389 if (cfs_hash_is_rehashing(hs))
1390 cfs_hash_rehash_cancel_locked(hs);
1391 cfs_hash_unlock(hs, 1);
1395 cfs_hash_for_each_exit(cfs_hash_t *hs)
1400 if (!cfs_hash_with_rehash(hs))
1402 cfs_hash_lock(hs, 1);
1403 remained = --hs->hs_iterators;
1404 bits = cfs_hash_rehash_bits(hs);
1405 cfs_hash_unlock(hs, 1);
1406 /* NB: it's race on cfs_has_t::hs_iterating, see above */
1408 hs->hs_iterating = 0;
1410 cfs_hash_rehash(hs, cfs_atomic_read(&hs->hs_count) <
1416 * For each item in the libcfs hash @hs call the passed callback @func
1417 * and pass to it as an argument each hash item and the private @data.
1419 * a) the function may sleep!
1420 * b) during the callback:
1421 * . the bucket lock is held so the callback must never sleep.
1422 * . if @removal_safe is true, use can remove current item by
1423 * cfs_hash_bd_del_locked
1426 cfs_hash_for_each_tight(cfs_hash_t *hs, cfs_hash_for_each_cb_t func,
1427 void *data, int remove_safe)
1429 cfs_hlist_node_t *hnode;
1430 cfs_hlist_node_t *pos;
1433 int excl = !!remove_safe;
1438 cfs_hash_for_each_enter(hs);
1440 cfs_hash_lock(hs, 0);
1441 LASSERT(!cfs_hash_is_rehashing(hs));
1443 cfs_hash_for_each_bucket(hs, &bd, i) {
1444 cfs_hlist_head_t *hhead;
1446 cfs_hash_bd_lock(hs, &bd, excl);
1447 if (func == NULL) { /* only glimpse size */
1448 count += bd.bd_bucket->hsb_count;
1449 cfs_hash_bd_unlock(hs, &bd, excl);
1453 cfs_hash_bd_for_each_hlist(hs, &bd, hhead) {
1454 cfs_hlist_for_each_safe(hnode, pos, hhead) {
1455 cfs_hash_bucket_validate(hs, &bd, hnode);
1458 if (func(hs, &bd, hnode, data)) {
1459 cfs_hash_bd_unlock(hs, &bd, excl);
1464 cfs_hash_bd_unlock(hs, &bd, excl);
1465 if (loop < CFS_HASH_LOOP_HOG)
1468 cfs_hash_unlock(hs, 0);
1470 cfs_hash_lock(hs, 0);
1473 cfs_hash_unlock(hs, 0);
1475 cfs_hash_for_each_exit(hs);
1480 cfs_hash_cond_opt_cb_t func;
1482 } cfs_hash_cond_arg_t;
1485 cfs_hash_cond_del_locked(cfs_hash_t *hs, cfs_hash_bd_t *bd,
1486 cfs_hlist_node_t *hnode, void *data)
1488 cfs_hash_cond_arg_t *cond = data;
1490 if (cond->func(cfs_hash_object(hs, hnode), cond->arg))
1491 cfs_hash_bd_del_locked(hs, bd, hnode);
1496 * Delete item from the libcfs hash @hs when @func return true.
1497 * The write lock being hold during loop for each bucket to avoid
1498 * any object be reference.
1501 cfs_hash_cond_del(cfs_hash_t *hs, cfs_hash_cond_opt_cb_t func, void *data)
1503 cfs_hash_cond_arg_t arg = {
1508 cfs_hash_for_each_tight(hs, cfs_hash_cond_del_locked, &arg, 1);
1510 CFS_EXPORT_SYMBOL(cfs_hash_cond_del);
1513 cfs_hash_for_each(cfs_hash_t *hs,
1514 cfs_hash_for_each_cb_t func, void *data)
1516 cfs_hash_for_each_tight(hs, func, data, 0);
1518 CFS_EXPORT_SYMBOL(cfs_hash_for_each);
1521 cfs_hash_for_each_safe(cfs_hash_t *hs,
1522 cfs_hash_for_each_cb_t func, void *data)
1524 cfs_hash_for_each_tight(hs, func, data, 1);
1526 CFS_EXPORT_SYMBOL(cfs_hash_for_each_safe);
1529 cfs_hash_peek(cfs_hash_t *hs, cfs_hash_bd_t *bd,
1530 cfs_hlist_node_t *hnode, void *data)
1533 return 1; /* return 1 to break the loop */
1537 cfs_hash_is_empty(cfs_hash_t *hs)
1541 cfs_hash_for_each_tight(hs, cfs_hash_peek, &empty, 0);
1544 CFS_EXPORT_SYMBOL(cfs_hash_is_empty);
1547 cfs_hash_size_get(cfs_hash_t *hs)
1549 return cfs_hash_with_counter(hs) ?
1550 cfs_atomic_read(&hs->hs_count) :
1551 cfs_hash_for_each_tight(hs, NULL, NULL, 0);
1553 CFS_EXPORT_SYMBOL(cfs_hash_size_get);
1556 * cfs_hash_for_each_relax:
1557 * Iterate the hash table and call @func on each item without
1558 * any lock. This function can't guarantee to finish iteration
1559 * if these features are enabled:
1561 * a. if rehash_key is enabled, an item can be moved from
1562 * one bucket to another bucket
1563 * b. user can remove non-zero-ref item from hash-table,
1564 * so the item can be removed from hash-table, even worse,
1565 * it's possible that user changed key and insert to another
1567 * there's no way for us to finish iteration correctly on previous
1568 * two cases, so iteration has to be stopped on change.
1571 cfs_hash_for_each_relax(cfs_hash_t *hs, cfs_hash_for_each_cb_t func, void *data)
1573 cfs_hlist_node_t *hnode;
1574 cfs_hlist_node_t *tmp;
1583 stop_on_change = cfs_hash_with_rehash_key(hs) ||
1584 !cfs_hash_with_no_itemref(hs) ||
1585 CFS_HOP(hs, put_locked) == NULL;
1586 cfs_hash_lock(hs, 0);
1587 LASSERT(!cfs_hash_is_rehashing(hs));
1589 cfs_hash_for_each_bucket(hs, &bd, i) {
1590 cfs_hlist_head_t *hhead;
1592 cfs_hash_bd_lock(hs, &bd, 0);
1593 version = cfs_hash_bd_version_get(&bd);
1595 cfs_hash_bd_for_each_hlist(hs, &bd, hhead) {
1596 for (hnode = hhead->first; hnode != NULL;) {
1597 cfs_hash_bucket_validate(hs, &bd, hnode);
1598 cfs_hash_get(hs, hnode);
1599 cfs_hash_bd_unlock(hs, &bd, 0);
1600 cfs_hash_unlock(hs, 0);
1602 rc = func(hs, &bd, hnode, data);
1604 cfs_hash_put(hs, hnode);
1608 cfs_hash_lock(hs, 0);
1609 cfs_hash_bd_lock(hs, &bd, 0);
1610 if (!stop_on_change) {
1612 cfs_hash_put_locked(hs, hnode);
1614 } else { /* bucket changed? */
1616 cfs_hash_bd_version_get(&bd))
1618 /* safe to continue because no change */
1619 hnode = hnode->next;
1621 if (rc) /* callback wants to break iteration */
1625 cfs_hash_bd_unlock(hs, &bd, 0);
1627 cfs_hash_unlock(hs, 0);
1633 cfs_hash_for_each_nolock(cfs_hash_t *hs,
1634 cfs_hash_for_each_cb_t func, void *data)
1638 if (cfs_hash_with_no_lock(hs) ||
1639 cfs_hash_with_rehash_key(hs) ||
1640 !cfs_hash_with_no_itemref(hs))
1641 RETURN(-EOPNOTSUPP);
1643 if (CFS_HOP(hs, get) == NULL ||
1644 (CFS_HOP(hs, put) == NULL &&
1645 CFS_HOP(hs, put_locked) == NULL))
1646 RETURN(-EOPNOTSUPP);
1648 cfs_hash_for_each_enter(hs);
1649 cfs_hash_for_each_relax(hs, func, data);
1650 cfs_hash_for_each_exit(hs);
1654 CFS_EXPORT_SYMBOL(cfs_hash_for_each_nolock);
1657 * For each hash bucket in the libcfs hash @hs call the passed callback
1658 * @func until all the hash buckets are empty. The passed callback @func
1659 * or the previously registered callback hs->hs_put must remove the item
1660 * from the hash. You may either use the cfs_hash_del() or hlist_del()
1661 * functions. No rwlocks will be held during the callback @func it is
1662 * safe to sleep if needed. This function will not terminate until the
1663 * hash is empty. Note it is still possible to concurrently add new
1664 * items in to the hash. It is the callers responsibility to ensure
1665 * the required locking is in place to prevent concurrent insertions.
1668 cfs_hash_for_each_empty(cfs_hash_t *hs,
1669 cfs_hash_for_each_cb_t func, void *data)
1674 if (cfs_hash_with_no_lock(hs))
1677 if (CFS_HOP(hs, get) == NULL ||
1678 (CFS_HOP(hs, put) == NULL &&
1679 CFS_HOP(hs, put_locked) == NULL))
1682 cfs_hash_for_each_enter(hs);
1683 while (cfs_hash_for_each_relax(hs, func, data)) {
1684 CDEBUG(D_INFO, "Try to empty hash: %s, loop: %u\n",
1687 cfs_hash_for_each_exit(hs);
1690 CFS_EXPORT_SYMBOL(cfs_hash_for_each_empty);
1693 cfs_hash_hlist_for_each(cfs_hash_t *hs, unsigned hindex,
1694 cfs_hash_for_each_cb_t func, void *data)
1696 cfs_hlist_head_t *hhead;
1697 cfs_hlist_node_t *hnode;
1700 cfs_hash_for_each_enter(hs);
1701 cfs_hash_lock(hs, 0);
1702 if (hindex >= CFS_HASH_NHLIST(hs))
1705 cfs_hash_bd_index_set(hs, hindex, &bd);
1707 cfs_hash_bd_lock(hs, &bd, 0);
1708 hhead = cfs_hash_bd_hhead(hs, &bd);
1709 cfs_hlist_for_each(hnode, hhead) {
1710 if (func(hs, &bd, hnode, data))
1713 cfs_hash_bd_unlock(hs, &bd, 0);
1715 cfs_hash_unlock(hs, 0);
1716 cfs_hash_for_each_exit(hs);
1719 CFS_EXPORT_SYMBOL(cfs_hash_hlist_for_each);
1722 * For each item in the libcfs hash @hs which matches the @key call
1723 * the passed callback @func and pass to it as an argument each hash
1724 * item and the private @data. During the callback the bucket lock
1725 * is held so the callback must never sleep.
1728 cfs_hash_for_each_key(cfs_hash_t *hs, void *key,
1729 cfs_hash_for_each_cb_t func, void *data)
1731 cfs_hlist_node_t *hnode;
1732 cfs_hash_bd_t bds[2];
1735 cfs_hash_lock(hs, 0);
1737 cfs_hash_dual_bd_get_and_lock(hs, key, bds, 0);
1739 cfs_hash_for_each_bd(bds, 2, i) {
1740 cfs_hlist_head_t *hlist = cfs_hash_bd_hhead(hs, &bds[i]);
1742 cfs_hlist_for_each(hnode, hlist) {
1743 cfs_hash_bucket_validate(hs, &bds[i], hnode);
1745 if (cfs_hash_keycmp(hs, key, hnode)) {
1746 if (func(hs, &bds[i], hnode, data))
1752 cfs_hash_dual_bd_unlock(hs, bds, 0);
1753 cfs_hash_unlock(hs, 0);
1755 CFS_EXPORT_SYMBOL(cfs_hash_for_each_key);
1758 * Rehash the libcfs hash @hs to the given @bits. This can be used
1759 * to grow the hash size when excessive chaining is detected, or to
1760 * shrink the hash when it is larger than needed. When the CFS_HASH_REHASH
1761 * flag is set in @hs the libcfs hash may be dynamically rehashed
1762 * during addition or removal if the hash's theta value exceeds
1763 * either the hs->hs_min_theta or hs->max_theta values. By default
1764 * these values are tuned to keep the chained hash depth small, and
1765 * this approach assumes a reasonably uniform hashing function. The
1766 * theta thresholds for @hs are tunable via cfs_hash_set_theta().
1769 cfs_hash_rehash_cancel_locked(cfs_hash_t *hs)
1773 /* need hold cfs_hash_lock(hs, 1) */
1774 LASSERT(cfs_hash_with_rehash(hs) &&
1775 !cfs_hash_with_no_lock(hs));
1777 if (!cfs_hash_is_rehashing(hs))
1780 if (cfs_wi_cancel(&hs->hs_rehash_wi)) {
1781 hs->hs_rehash_bits = 0;
1785 for (i = 2; cfs_hash_is_rehashing(hs); i++) {
1786 cfs_hash_unlock(hs, 1);
1787 /* raise console warning while waiting too long */
1788 CDEBUG(IS_PO2(i >> 3) ? D_WARNING : D_INFO,
1789 "hash %s is still rehashing, rescheded %d\n",
1790 hs->hs_name, i - 1);
1792 cfs_hash_lock(hs, 1);
1795 CFS_EXPORT_SYMBOL(cfs_hash_rehash_cancel_locked);
1798 cfs_hash_rehash_cancel(cfs_hash_t *hs)
1800 cfs_hash_lock(hs, 1);
1801 cfs_hash_rehash_cancel_locked(hs);
1802 cfs_hash_unlock(hs, 1);
1804 CFS_EXPORT_SYMBOL(cfs_hash_rehash_cancel);
1807 cfs_hash_rehash(cfs_hash_t *hs, int do_rehash)
1811 LASSERT(cfs_hash_with_rehash(hs) && !cfs_hash_with_no_lock(hs));
1813 cfs_hash_lock(hs, 1);
1815 rc = cfs_hash_rehash_bits(hs);
1817 cfs_hash_unlock(hs, 1);
1821 hs->hs_rehash_bits = rc;
1823 /* launch and return */
1824 cfs_wi_schedule(&hs->hs_rehash_wi);
1825 cfs_hash_unlock(hs, 1);
1829 /* rehash right now */
1830 cfs_hash_unlock(hs, 1);
1832 return cfs_hash_rehash_worker(&hs->hs_rehash_wi);
1834 CFS_EXPORT_SYMBOL(cfs_hash_rehash);
1837 cfs_hash_rehash_bd(cfs_hash_t *hs, cfs_hash_bd_t *old)
1840 cfs_hlist_head_t *hhead;
1841 cfs_hlist_node_t *hnode;
1842 cfs_hlist_node_t *pos;
1846 /* hold cfs_hash_lock(hs, 1), so don't need any bucket lock */
1847 cfs_hash_bd_for_each_hlist(hs, old, hhead) {
1848 cfs_hlist_for_each_safe(hnode, pos, hhead) {
1849 key = cfs_hash_key(hs, hnode);
1850 LASSERT(key != NULL);
1851 /* Validate hnode is in the correct bucket. */
1852 cfs_hash_bucket_validate(hs, old, hnode);
1854 * Delete from old hash bucket; move to new bucket.
1855 * ops->hs_key must be defined.
1857 cfs_hash_bd_from_key(hs, hs->hs_rehash_buckets,
1858 hs->hs_rehash_bits, key, &new);
1859 cfs_hash_bd_move_locked(hs, old, &new, hnode);
1868 cfs_hash_rehash_worker(cfs_workitem_t *wi)
1870 cfs_hash_t *hs = container_of(wi, cfs_hash_t, hs_rehash_wi);
1871 cfs_hash_bucket_t **bkts;
1873 unsigned int old_size;
1874 unsigned int new_size;
1880 LASSERT (hs != NULL && cfs_hash_with_rehash(hs));
1882 cfs_hash_lock(hs, 0);
1883 LASSERT(cfs_hash_is_rehashing(hs));
1885 old_size = CFS_HASH_NBKT(hs);
1886 new_size = CFS_HASH_RH_NBKT(hs);
1888 cfs_hash_unlock(hs, 0);
1891 * don't need hs::hs_rwlock for hs::hs_buckets,
1892 * because nobody can change bkt-table except me.
1894 bkts = cfs_hash_buckets_realloc(hs, hs->hs_buckets,
1895 old_size, new_size);
1896 cfs_hash_lock(hs, 1);
1902 if (bkts == hs->hs_buckets) {
1903 bkts = NULL; /* do nothing */
1907 rc = __cfs_hash_theta(hs);
1908 if ((rc >= hs->hs_min_theta) && (rc <= hs->hs_max_theta)) {
1909 /* free the new allocated bkt-table */
1910 old_size = new_size;
1911 new_size = CFS_HASH_NBKT(hs);
1916 LASSERT(hs->hs_rehash_buckets == NULL);
1917 hs->hs_rehash_buckets = bkts;
1920 cfs_hash_for_each_bucket(hs, &bd, i) {
1921 if (cfs_hash_is_exiting(hs)) {
1923 /* someone wants to destroy the hash, abort now */
1924 if (old_size < new_size) /* OK to free old bkt-table */
1926 /* it's shrinking, need free new bkt-table */
1927 hs->hs_rehash_buckets = NULL;
1928 old_size = new_size;
1929 new_size = CFS_HASH_NBKT(hs);
1933 count += cfs_hash_rehash_bd(hs, &bd);
1934 if (count < CFS_HASH_LOOP_HOG ||
1935 cfs_hash_is_iterating(hs)) { /* need to finish ASAP */
1940 cfs_hash_unlock(hs, 1);
1942 cfs_hash_lock(hs, 1);
1945 hs->hs_rehash_count++;
1947 bkts = hs->hs_buckets;
1948 hs->hs_buckets = hs->hs_rehash_buckets;
1949 hs->hs_rehash_buckets = NULL;
1951 hs->hs_cur_bits = hs->hs_rehash_bits;
1953 hs->hs_rehash_bits = 0;
1955 cfs_wi_exit(wi); /* never be scheduled again */
1956 bsize = cfs_hash_bkt_size(hs);
1957 cfs_hash_unlock(hs, 1);
1958 /* can't refer to @hs anymore because it could be destroyed */
1960 cfs_hash_buckets_free(bkts, bsize, new_size, old_size);
1962 CDEBUG(D_INFO, "early quit of of rehashing: %d\n", rc);
1963 /* cfs_workitem require us to always return 0 */
1968 * Rehash the object referenced by @hnode in the libcfs hash @hs. The
1969 * @old_key must be provided to locate the objects previous location
1970 * in the hash, and the @new_key will be used to reinsert the object.
1971 * Use this function instead of a cfs_hash_add() + cfs_hash_del()
1972 * combo when it is critical that there is no window in time where the
1973 * object is missing from the hash. When an object is being rehashed
1974 * the registered cfs_hash_get() and cfs_hash_put() functions will
1977 void cfs_hash_rehash_key(cfs_hash_t *hs, void *old_key,
1978 void *new_key, cfs_hlist_node_t *hnode)
1980 cfs_hash_bd_t bds[3];
1981 cfs_hash_bd_t old_bds[2];
1982 cfs_hash_bd_t new_bd;
1984 LASSERT(!cfs_hlist_unhashed(hnode));
1986 cfs_hash_lock(hs, 0);
1988 cfs_hash_dual_bd_get(hs, old_key, old_bds);
1989 cfs_hash_bd_get(hs, new_key, &new_bd);
1991 bds[0] = old_bds[0];
1992 bds[1] = old_bds[1];
1995 /* NB: bds[0] and bds[1] are ordered already */
1996 cfs_hash_bd_order(&bds[1], &bds[2]);
1997 cfs_hash_bd_order(&bds[0], &bds[1]);
1999 cfs_hash_multi_bd_lock(hs, bds, 3, 1);
2000 if (likely(old_bds[1].bd_bucket == NULL)) {
2001 cfs_hash_bd_move_locked(hs, &old_bds[0], &new_bd, hnode);
2003 cfs_hash_dual_bd_finddel_locked(hs, old_bds, old_key, hnode);
2004 cfs_hash_bd_add_locked(hs, &new_bd, hnode);
2006 /* overwrite key inside locks, otherwise may screw up with
2007 * other operations, i.e: rehash */
2008 cfs_hash_keycpy(hs, new_key, hnode);
2010 cfs_hash_multi_bd_unlock(hs, bds, 3, 1);
2011 cfs_hash_unlock(hs, 0);
2013 CFS_EXPORT_SYMBOL(cfs_hash_rehash_key);
2015 int cfs_hash_debug_header(char *str, int size)
2017 return snprintf(str, size, "%-*s%6s%6s%6s%6s%6s%6s%6s%7s%8s%8s%8s%s\n",
2018 CFS_HASH_BIGNAME_LEN,
2019 "name", "cur", "min", "max", "theta", "t-min", "t-max",
2020 "flags", "rehash", "count", "maxdep", "maxdepb",
2023 CFS_EXPORT_SYMBOL(cfs_hash_debug_header);
2025 static cfs_hash_bucket_t **
2026 cfs_hash_full_bkts(cfs_hash_t *hs)
2028 /* NB: caller should hold hs->hs_rwlock if REHASH is set */
2029 if (hs->hs_rehash_buckets == NULL)
2030 return hs->hs_buckets;
2032 LASSERT(hs->hs_rehash_bits != 0);
2033 return hs->hs_rehash_bits > hs->hs_cur_bits ?
2034 hs->hs_rehash_buckets : hs->hs_buckets;
2038 cfs_hash_full_nbkt(cfs_hash_t *hs)
2040 /* NB: caller should hold hs->hs_rwlock if REHASH is set */
2041 if (hs->hs_rehash_buckets == NULL)
2042 return CFS_HASH_NBKT(hs);
2044 LASSERT(hs->hs_rehash_bits != 0);
2045 return hs->hs_rehash_bits > hs->hs_cur_bits ?
2046 CFS_HASH_RH_NBKT(hs) : CFS_HASH_NBKT(hs);
2049 int cfs_hash_debug_str(cfs_hash_t *hs, char *str, int size)
2051 int dist[8] = { 0, };
2059 if (str == NULL || size == 0)
2062 cfs_hash_lock(hs, 0);
2063 theta = __cfs_hash_theta(hs);
2065 c += snprintf(str + c, size - c, "%-*s ",
2066 CFS_HASH_BIGNAME_LEN, hs->hs_name);
2067 c += snprintf(str + c, size - c, "%5d ", 1 << hs->hs_cur_bits);
2068 c += snprintf(str + c, size - c, "%5d ", 1 << hs->hs_min_bits);
2069 c += snprintf(str + c, size - c, "%5d ", 1 << hs->hs_max_bits);
2070 c += snprintf(str + c, size - c, "%d.%03d ",
2071 __cfs_hash_theta_int(theta),
2072 __cfs_hash_theta_frac(theta));
2073 c += snprintf(str + c, size - c, "%d.%03d ",
2074 __cfs_hash_theta_int(hs->hs_min_theta),
2075 __cfs_hash_theta_frac(hs->hs_min_theta));
2076 c += snprintf(str + c, size - c, "%d.%03d ",
2077 __cfs_hash_theta_int(hs->hs_max_theta),
2078 __cfs_hash_theta_frac(hs->hs_max_theta));
2079 c += snprintf(str + c, size - c, " 0x%02x ", hs->hs_flags);
2080 c += snprintf(str + c, size - c, "%6d ", hs->hs_rehash_count);
2083 * The distribution is a summary of the chained hash depth in
2084 * each of the libcfs hash buckets. Each buckets hsb_count is
2085 * divided by the hash theta value and used to generate a
2086 * histogram of the hash distribution. A uniform hash will
2087 * result in all hash buckets being close to the average thus
2088 * only the first few entries in the histogram will be non-zero.
2089 * If you hash function results in a non-uniform hash the will
2090 * be observable by outlier bucks in the distribution histogram.
2092 * Uniform hash distribution: 128/128/0/0/0/0/0/0
2093 * Non-Uniform hash distribution: 128/125/0/0/0/0/2/1
2095 for (i = 0; i < cfs_hash_full_nbkt(hs); i++) {
2098 bd.bd_bucket = cfs_hash_full_bkts(hs)[i];
2099 cfs_hash_bd_lock(hs, &bd, 0);
2100 if (maxdep < bd.bd_bucket->hsb_depmax) {
2101 maxdep = bd.bd_bucket->hsb_depmax;
2103 maxdepb = cfs_ffz(~maxdep);
2106 total += bd.bd_bucket->hsb_count;
2107 dist[min(__cfs_fls(bd.bd_bucket->hsb_count/max(theta,1)),7)]++;
2108 cfs_hash_bd_unlock(hs, &bd, 0);
2111 c += snprintf(str + c, size - c, "%7d ", total);
2112 c += snprintf(str + c, size - c, "%7d ", maxdep);
2113 c += snprintf(str + c, size - c, "%7d ", maxdepb);
2114 for (i = 0; i < 8; i++)
2115 c += snprintf(str + c, size - c, "%d%c", dist[i],
2116 (i == 7) ? '\n' : '/');
2118 cfs_hash_unlock(hs, 0);
2122 CFS_EXPORT_SYMBOL(cfs_hash_debug_str);