Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/lib/lru_cache.c

  1 /*
  2    lru_cache.c
  3 
  4    This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
  5 
  6    Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
  7    Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
  8    Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
  9 
 10    drbd is free software; you can redistribute it and/or modify
 11    it under the terms of the GNU General Public License as published by
 12    the Free Software Foundation; either version 2, or (at your option)
 13    any later version.
 14 
 15    drbd is distributed in the hope that it will be useful,
 16    but WITHOUT ANY WARRANTY; without even the implied warranty of
 17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 18    GNU General Public License for more details.
 19 
 20    You should have received a copy of the GNU General Public License
 21    along with drbd; see the file COPYING.  If not, write to
 22    the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 23 
 24  */
 25 
 26 #include <linux/module.h>
 27 #include <linux/bitops.h>
 28 #include <linux/slab.h>
 29 #include <linux/string.h> /* for memset */
 30 #include <linux/seq_file.h> /* for seq_printf */
 31 #include <linux/lru_cache.h>
 32 
 33 MODULE_AUTHOR("Philipp Reisner <phil@linbit.com>, "
 34               "Lars Ellenberg <lars@linbit.com>");
 35 MODULE_DESCRIPTION("lru_cache - Track sets of hot objects");
 36 MODULE_LICENSE("GPL");
 37 
 38 /* this is developers aid only.
 39  * it catches concurrent access (lack of locking on the users part) */
 40 #define PARANOIA_ENTRY() do {           \
 41         BUG_ON(!lc);                    \
 42         BUG_ON(!lc->nr_elements);       \
 43         BUG_ON(test_and_set_bit(__LC_PARANOIA, &lc->flags)); \
 44 } while (0)
 45 
 46 #define RETURN(x...)     do { \
 47         clear_bit_unlock(__LC_PARANOIA, &lc->flags); \
 48         return x ; } while (0)
 49 
 50 /* BUG() if e is not one of the elements tracked by lc */
 51 #define PARANOIA_LC_ELEMENT(lc, e) do { \
 52         struct lru_cache *lc_ = (lc);   \
 53         struct lc_element *e_ = (e);    \
 54         unsigned i = e_->lc_index;      \
 55         BUG_ON(i >= lc_->nr_elements);  \
 56         BUG_ON(lc_->lc_element[i] != e_); } while (0)
 57 
 58 
 59 /* We need to atomically
 60  *  - try to grab the lock (set LC_LOCKED)
 61  *  - only if there is no pending transaction
 62  *    (neither LC_DIRTY nor LC_STARVING is set)
 63  * Because of PARANOIA_ENTRY() above abusing lc->flags as well,
 64  * it is not sufficient to just say
 65  *      return 0 == cmpxchg(&lc->flags, 0, LC_LOCKED);
 66  */
 67 int lc_try_lock(struct lru_cache *lc)
 68 {
 69         unsigned long val;
 70         do {
 71                 val = cmpxchg(&lc->flags, 0, LC_LOCKED);
 72         } while (unlikely (val == LC_PARANOIA));
 73         /* Spin until no-one is inside a PARANOIA_ENTRY()/RETURN() section. */
 74         return 0 == val;
 75 #if 0
 76         /* Alternative approach, spin in case someone enters or leaves a
 77          * PARANOIA_ENTRY()/RETURN() section. */
 78         unsigned long old, new, val;
 79         do {
 80                 old = lc->flags & LC_PARANOIA;
 81                 new = old | LC_LOCKED;
 82                 val = cmpxchg(&lc->flags, old, new);
 83         } while (unlikely (val == (old ^ LC_PARANOIA)));
 84         return old == val;
 85 #endif
 86 }
 87 
 88 /**
 89  * lc_create - prepares to track objects in an active set
 90  * @name: descriptive name only used in lc_seq_printf_stats and lc_seq_dump_details
 91  * @max_pending_changes: maximum changes to accumulate until a transaction is required
 92  * @e_count: number of elements allowed to be active simultaneously
 93  * @e_size: size of the tracked objects
 94  * @e_off: offset to the &struct lc_element member in a tracked object
 95  *
 96  * Returns a pointer to a newly initialized struct lru_cache on success,
 97  * or NULL on (allocation) failure.
 98  */
 99 struct lru_cache *lc_create(const char *name, struct kmem_cache *cache,
100                 unsigned max_pending_changes,
101                 unsigned e_count, size_t e_size, size_t e_off)
102 {
103         struct hlist_head *slot = NULL;
104         struct lc_element **element = NULL;
105         struct lru_cache *lc;
106         struct lc_element *e;
107         unsigned cache_obj_size = kmem_cache_size(cache);
108         unsigned i;
109 
110         WARN_ON(cache_obj_size < e_size);
111         if (cache_obj_size < e_size)
112                 return NULL;
113 
114         /* e_count too big; would probably fail the allocation below anyways.
115          * for typical use cases, e_count should be few thousand at most. */
116         if (e_count > LC_MAX_ACTIVE)
117                 return NULL;
118 
119         slot = kcalloc(e_count, sizeof(struct hlist_head), GFP_KERNEL);
120         if (!slot)
121                 goto out_fail;
122         element = kzalloc(e_count * sizeof(struct lc_element *), GFP_KERNEL);
123         if (!element)
124                 goto out_fail;
125 
126         lc = kzalloc(sizeof(*lc), GFP_KERNEL);
127         if (!lc)
128                 goto out_fail;
129 
130         INIT_LIST_HEAD(&lc->in_use);
131         INIT_LIST_HEAD(&lc->lru);
132         INIT_LIST_HEAD(&lc->free);
133         INIT_LIST_HEAD(&lc->to_be_changed);
134 
135         lc->name = name;
136         lc->element_size = e_size;
137         lc->element_off = e_off;
138         lc->nr_elements = e_count;
139         lc->max_pending_changes = max_pending_changes;
140         lc->lc_cache = cache;
141         lc->lc_element = element;
142         lc->lc_slot = slot;
143 
144         /* preallocate all objects */
145         for (i = 0; i < e_count; i++) {
146                 void *p = kmem_cache_alloc(cache, GFP_KERNEL);
147                 if (!p)
148                         break;
149                 memset(p, 0, lc->element_size);
150                 e = p + e_off;
151                 e->lc_index = i;
152                 e->lc_number = LC_FREE;
153                 e->lc_new_number = LC_FREE;
154                 list_add(&e->list, &lc->free);
155                 element[i] = e;
156         }
157         if (i == e_count)
158                 return lc;
159 
160         /* else: could not allocate all elements, give up */
161         for (i--; i; i--) {
162                 void *p = element[i];
163                 kmem_cache_free(cache, p - e_off);
164         }
165         kfree(lc);
166 out_fail:
167         kfree(element);
168         kfree(slot);
169         return NULL;
170 }
171 
172 static void lc_free_by_index(struct lru_cache *lc, unsigned i)
173 {
174         void *p = lc->lc_element[i];
175         WARN_ON(!p);
176         if (p) {
177                 p -= lc->element_off;
178                 kmem_cache_free(lc->lc_cache, p);
179         }
180 }
181 
182 /**
183  * lc_destroy - frees memory allocated by lc_create()
184  * @lc: the lru cache to destroy
185  */
186 void lc_destroy(struct lru_cache *lc)
187 {
188         unsigned i;
189         if (!lc)
190                 return;
191         for (i = 0; i < lc->nr_elements; i++)
192                 lc_free_by_index(lc, i);
193         kfree(lc->lc_element);
194         kfree(lc->lc_slot);
195         kfree(lc);
196 }
197 
198 /**
199  * lc_reset - does a full reset for @lc and the hash table slots.
200  * @lc: the lru cache to operate on
201  *
202  * It is roughly the equivalent of re-allocating a fresh lru_cache object,
203  * basically a short cut to lc_destroy(lc); lc = lc_create(...);
204  */
205 void lc_reset(struct lru_cache *lc)
206 {
207         unsigned i;
208 
209         INIT_LIST_HEAD(&lc->in_use);
210         INIT_LIST_HEAD(&lc->lru);
211         INIT_LIST_HEAD(&lc->free);
212         INIT_LIST_HEAD(&lc->to_be_changed);
213         lc->used = 0;
214         lc->hits = 0;
215         lc->misses = 0;
216         lc->starving = 0;
217         lc->locked = 0;
218         lc->changed = 0;
219         lc->pending_changes = 0;
220         lc->flags = 0;
221         memset(lc->lc_slot, 0, sizeof(struct hlist_head) * lc->nr_elements);
222 
223         for (i = 0; i < lc->nr_elements; i++) {
224                 struct lc_element *e = lc->lc_element[i];
225                 void *p = e;
226                 p -= lc->element_off;
227                 memset(p, 0, lc->element_size);
228                 /* re-init it */
229                 e->lc_index = i;
230                 e->lc_number = LC_FREE;
231                 e->lc_new_number = LC_FREE;
232                 list_add(&e->list, &lc->free);
233         }
234 }
235 
236 /**
237  * lc_seq_printf_stats - print stats about @lc into @seq
238  * @seq: the seq_file to print into
239  * @lc: the lru cache to print statistics of
240  */
241 void lc_seq_printf_stats(struct seq_file *seq, struct lru_cache *lc)
242 {
243         /* NOTE:
244          * total calls to lc_get are
245          * (starving + hits + misses)
246          * misses include "locked" count (update from an other thread in
247          * progress) and "changed", when this in fact lead to an successful
248          * update of the cache.
249          */
250         seq_printf(seq, "\t%s: used:%u/%u hits:%lu misses:%lu starving:%lu locked:%lu changed:%lu\n",
251                    lc->name, lc->used, lc->nr_elements,
252                    lc->hits, lc->misses, lc->starving, lc->locked, lc->changed);
253 }
254 
255 static struct hlist_head *lc_hash_slot(struct lru_cache *lc, unsigned int enr)
256 {
257         return  lc->lc_slot + (enr % lc->nr_elements);
258 }
259 
260 
261 static struct lc_element *__lc_find(struct lru_cache *lc, unsigned int enr,
262                 bool include_changing)
263 {
264         struct lc_element *e;
265 
266         BUG_ON(!lc);
267         BUG_ON(!lc->nr_elements);
268         hlist_for_each_entry(e, lc_hash_slot(lc, enr), colision) {
269                 /* "about to be changed" elements, pending transaction commit,
270                  * are hashed by their "new number". "Normal" elements have
271                  * lc_number == lc_new_number. */
272                 if (e->lc_new_number != enr)
273                         continue;
274                 if (e->lc_new_number == e->lc_number || include_changing)
275                         return e;
276                 break;
277         }
278         return NULL;
279 }
280 
281 /**
282  * lc_find - find element by label, if present in the hash table
283  * @lc: The lru_cache object
284  * @enr: element number
285  *
286  * Returns the pointer to an element, if the element with the requested
287  * "label" or element number is present in the hash table,
288  * or NULL if not found. Does not change the refcnt.
289  * Ignores elements that are "about to be used", i.e. not yet in the active
290  * set, but still pending transaction commit.
291  */
292 struct lc_element *lc_find(struct lru_cache *lc, unsigned int enr)
293 {
294         return __lc_find(lc, enr, 0);
295 }
296 
297 /**
298  * lc_is_used - find element by label
299  * @lc: The lru_cache object
300  * @enr: element number
301  *
302  * Returns true, if the element with the requested "label" or element number is
303  * present in the hash table, and is used (refcnt > 0).
304  * Also finds elements that are not _currently_ used but only "about to be
305  * used", i.e. on the "to_be_changed" list, pending transaction commit.
306  */
307 bool lc_is_used(struct lru_cache *lc, unsigned int enr)
308 {
309         struct lc_element *e = __lc_find(lc, enr, 1);
310         return e && e->refcnt;
311 }
312 
313 /**
314  * lc_del - removes an element from the cache
315  * @lc: The lru_cache object
316  * @e: The element to remove
317  *
318  * @e must be unused (refcnt == 0). Moves @e from "lru" to "free" list,
319  * sets @e->enr to %LC_FREE.
320  */
321 void lc_del(struct lru_cache *lc, struct lc_element *e)
322 {
323         PARANOIA_ENTRY();
324         PARANOIA_LC_ELEMENT(lc, e);
325         BUG_ON(e->refcnt);
326 
327         e->lc_number = e->lc_new_number = LC_FREE;
328         hlist_del_init(&e->colision);
329         list_move(&e->list, &lc->free);
330         RETURN();
331 }
332 
333 static struct lc_element *lc_prepare_for_change(struct lru_cache *lc, unsigned new_number)
334 {
335         struct list_head *n;
336         struct lc_element *e;
337 
338         if (!list_empty(&lc->free))
339                 n = lc->free.next;
340         else if (!list_empty(&lc->lru))
341                 n = lc->lru.prev;
342         else
343                 return NULL;
344 
345         e = list_entry(n, struct lc_element, list);
346         PARANOIA_LC_ELEMENT(lc, e);
347 
348         e->lc_new_number = new_number;
349         if (!hlist_unhashed(&e->colision))
350                 __hlist_del(&e->colision);
351         hlist_add_head(&e->colision, lc_hash_slot(lc, new_number));
352         list_move(&e->list, &lc->to_be_changed);
353 
354         return e;
355 }
356 
357 static int lc_unused_element_available(struct lru_cache *lc)
358 {
359         if (!list_empty(&lc->free))
360                 return 1; /* something on the free list */
361         if (!list_empty(&lc->lru))
362                 return 1;  /* something to evict */
363 
364         return 0;
365 }
366 
367 /* used as internal flags to __lc_get */
368 enum {
369         LC_GET_MAY_CHANGE = 1,
370         LC_GET_MAY_USE_UNCOMMITTED = 2,
371 };
372 
373 static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, unsigned int flags)
374 {
375         struct lc_element *e;
376 
377         PARANOIA_ENTRY();
378         if (lc->flags & LC_STARVING) {
379                 ++lc->starving;
380                 RETURN(NULL);
381         }
382 
383         e = __lc_find(lc, enr, 1);
384         /* if lc_new_number != lc_number,
385          * this enr is currently being pulled in already,
386          * and will be available once the pending transaction
387          * has been committed. */
388         if (e) {
389                 if (e->lc_new_number != e->lc_number) {
390                         /* It has been found above, but on the "to_be_changed"
391                          * list, not yet committed.  Don't pull it in twice,
392                          * wait for the transaction, then try again...
393                          */
394                         if (!(flags & LC_GET_MAY_USE_UNCOMMITTED))
395                                 RETURN(NULL);
396                         /* ... unless the caller is aware of the implications,
397                          * probably preparing a cumulative transaction. */
398                         ++e->refcnt;
399                         ++lc->hits;
400                         RETURN(e);
401                 }
402                 /* else: lc_new_number == lc_number; a real hit. */
403                 ++lc->hits;
404                 if (e->refcnt++ == 0)
405                         lc->used++;
406                 list_move(&e->list, &lc->in_use); /* Not evictable... */
407                 RETURN(e);
408         }
409         /* e == NULL */
410 
411         ++lc->misses;
412         if (!(flags & LC_GET_MAY_CHANGE))
413                 RETURN(NULL);
414 
415         /* To avoid races with lc_try_lock(), first, mark us dirty
416          * (using test_and_set_bit, as it implies memory barriers), ... */
417         test_and_set_bit(__LC_DIRTY, &lc->flags);
418 
419         /* ... only then check if it is locked anyways. If lc_unlock clears
420          * the dirty bit again, that's not a problem, we will come here again.
421          */
422         if (test_bit(__LC_LOCKED, &lc->flags)) {
423                 ++lc->locked;
424                 RETURN(NULL);
425         }
426 
427         /* In case there is nothing available and we can not kick out
428          * the LRU element, we have to wait ...
429          */
430         if (!lc_unused_element_available(lc)) {
431                 __set_bit(__LC_STARVING, &lc->flags);
432                 RETURN(NULL);
433         }
434 
435         /* It was not present in the active set.  We are going to recycle an
436          * unused (or even "free") element, but we won't accumulate more than
437          * max_pending_changes changes.  */
438         if (lc->pending_changes >= lc->max_pending_changes)
439                 RETURN(NULL);
440 
441         e = lc_prepare_for_change(lc, enr);
442         BUG_ON(!e);
443 
444         clear_bit(__LC_STARVING, &lc->flags);
445         BUG_ON(++e->refcnt != 1);
446         lc->used++;
447         lc->pending_changes++;
448 
449         RETURN(e);
450 }
451 
452 /**
453  * lc_get - get element by label, maybe change the active set
454  * @lc: the lru cache to operate on
455  * @enr: the label to look up
456  *
457  * Finds an element in the cache, increases its usage count,
458  * "touches" and returns it.
459  *
460  * In case the requested number is not present, it needs to be added to the
461  * cache. Therefore it is possible that an other element becomes evicted from
462  * the cache. In either case, the user is notified so he is able to e.g. keep
463  * a persistent log of the cache changes, and therefore the objects in use.
464  *
465  * Return values:
466  *  NULL
467  *     The cache was marked %LC_STARVING,
468  *     or the requested label was not in the active set
469  *     and a changing transaction is still pending (@lc was marked %LC_DIRTY).
470  *     Or no unused or free element could be recycled (@lc will be marked as
471  *     %LC_STARVING, blocking further lc_get() operations).
472  *
473  *  pointer to the element with the REQUESTED element number.
474  *     In this case, it can be used right away
475  *
476  *  pointer to an UNUSED element with some different element number,
477  *          where that different number may also be %LC_FREE.
478  *
479  *          In this case, the cache is marked %LC_DIRTY,
480  *          so lc_try_lock() will no longer succeed.
481  *          The returned element pointer is moved to the "to_be_changed" list,
482  *          and registered with the new element number on the hash collision chains,
483  *          so it is possible to pick it up from lc_is_used().
484  *          Up to "max_pending_changes" (see lc_create()) can be accumulated.
485  *          The user now should do whatever housekeeping is necessary,
486  *          typically serialize on lc_try_lock_for_transaction(), then call
487  *          lc_committed(lc) and lc_unlock(), to finish the change.
488  *
489  * NOTE: The user needs to check the lc_number on EACH use, so he recognizes
490  *       any cache set change.
491  */
492 struct lc_element *lc_get(struct lru_cache *lc, unsigned int enr)
493 {
494         return __lc_get(lc, enr, LC_GET_MAY_CHANGE);
495 }
496 
497 /**
498  * lc_get_cumulative - like lc_get; also finds to-be-changed elements
499  * @lc: the lru cache to operate on
500  * @enr: the label to look up
501  *
502  * Unlike lc_get this also returns the element for @enr, if it is belonging to
503  * a pending transaction, so the return values are like for lc_get(),
504  * plus:
505  *
506  * pointer to an element already on the "to_be_changed" list.
507  *      In this case, the cache was already marked %LC_DIRTY.
508  *
509  * Caller needs to make sure that the pending transaction is completed,
510  * before proceeding to actually use this element.
511  */
512 struct lc_element *lc_get_cumulative(struct lru_cache *lc, unsigned int enr)
513 {
514         return __lc_get(lc, enr, LC_GET_MAY_CHANGE|LC_GET_MAY_USE_UNCOMMITTED);
515 }
516 
517 /**
518  * lc_try_get - get element by label, if present; do not change the active set
519  * @lc: the lru cache to operate on
520  * @enr: the label to look up
521  *
522  * Finds an element in the cache, increases its usage count,
523  * "touches" and returns it.
524  *
525  * Return values:
526  *  NULL
527  *     The cache was marked %LC_STARVING,
528  *     or the requested label was not in the active set
529  *
530  *  pointer to the element with the REQUESTED element number.
531  *     In this case, it can be used right away
532  */
533 struct lc_element *lc_try_get(struct lru_cache *lc, unsigned int enr)
534 {
535         return __lc_get(lc, enr, 0);
536 }
537 
538 /**
539  * lc_committed - tell @lc that pending changes have been recorded
540  * @lc: the lru cache to operate on
541  *
542  * User is expected to serialize on explicit lc_try_lock_for_transaction()
543  * before the transaction is started, and later needs to lc_unlock() explicitly
544  * as well.
545  */
546 void lc_committed(struct lru_cache *lc)
547 {
548         struct lc_element *e, *tmp;
549 
550         PARANOIA_ENTRY();
551         list_for_each_entry_safe(e, tmp, &lc->to_be_changed, list) {
552                 /* count number of changes, not number of transactions */
553                 ++lc->changed;
554                 e->lc_number = e->lc_new_number;
555                 list_move(&e->list, &lc->in_use);
556         }
557         lc->pending_changes = 0;
558         RETURN();
559 }
560 
561 
562 /**
563  * lc_put - give up refcnt of @e
564  * @lc: the lru cache to operate on
565  * @e: the element to put
566  *
567  * If refcnt reaches zero, the element is moved to the lru list,
568  * and a %LC_STARVING (if set) is cleared.
569  * Returns the new (post-decrement) refcnt.
570  */
571 unsigned int lc_put(struct lru_cache *lc, struct lc_element *e)
572 {
573         PARANOIA_ENTRY();
574         PARANOIA_LC_ELEMENT(lc, e);
575         BUG_ON(e->refcnt == 0);
576         BUG_ON(e->lc_number != e->lc_new_number);
577         if (--e->refcnt == 0) {
578                 /* move it to the front of LRU. */
579                 list_move(&e->list, &lc->lru);
580                 lc->used--;
581                 clear_bit_unlock(__LC_STARVING, &lc->flags);
582         }
583         RETURN(e->refcnt);
584 }
585 
586 /**
587  * lc_element_by_index
588  * @lc: the lru cache to operate on
589  * @i: the index of the element to return
590  */
591 struct lc_element *lc_element_by_index(struct lru_cache *lc, unsigned i)
592 {
593         BUG_ON(i >= lc->nr_elements);
594         BUG_ON(lc->lc_element[i] == NULL);
595         BUG_ON(lc->lc_element[i]->lc_index != i);
596         return lc->lc_element[i];
597 }
598 
599 /**
600  * lc_index_of
601  * @lc: the lru cache to operate on
602  * @e: the element to query for its index position in lc->element
603  */
604 unsigned int lc_index_of(struct lru_cache *lc, struct lc_element *e)
605 {
606         PARANOIA_LC_ELEMENT(lc, e);
607         return e->lc_index;
608 }
609 
610 /**
611  * lc_set - associate index with label
612  * @lc: the lru cache to operate on
613  * @enr: the label to set
614  * @index: the element index to associate label with.
615  *
616  * Used to initialize the active set to some previously recorded state.
617  */
618 void lc_set(struct lru_cache *lc, unsigned int enr, int index)
619 {
620         struct lc_element *e;
621         struct list_head *lh;
622 
623         if (index < 0 || index >= lc->nr_elements)
624                 return;
625 
626         e = lc_element_by_index(lc, index);
627         BUG_ON(e->lc_number != e->lc_new_number);
628         BUG_ON(e->refcnt != 0);
629 
630         e->lc_number = e->lc_new_number = enr;
631         hlist_del_init(&e->colision);
632         if (enr == LC_FREE)
633                 lh = &lc->free;
634         else {
635                 hlist_add_head(&e->colision, lc_hash_slot(lc, enr));
636                 lh = &lc->lru;
637         }
638         list_move(&e->list, lh);
639 }
640 
641 /**
642  * lc_dump - Dump a complete LRU cache to seq in textual form.
643  * @lc: the lru cache to operate on
644  * @seq: the &struct seq_file pointer to seq_printf into
645  * @utext: user supplied additional "heading" or other info
646  * @detail: function pointer the user may provide to dump further details
647  * of the object the lc_element is embedded in. May be NULL.
648  * Note: a leading space ' ' and trailing newline '\n' is implied.
649  */
650 void lc_seq_dump_details(struct seq_file *seq, struct lru_cache *lc, char *utext,
651              void (*detail) (struct seq_file *, struct lc_element *))
652 {
653         unsigned int nr_elements = lc->nr_elements;
654         struct lc_element *e;
655         int i;
656 
657         seq_printf(seq, "\tnn: lc_number (new nr) refcnt %s\n ", utext);
658         for (i = 0; i < nr_elements; i++) {
659                 e = lc_element_by_index(lc, i);
660                 if (e->lc_number != e->lc_new_number)
661                         seq_printf(seq, "\t%5d: %6d %8d %6d ",
662                                 i, e->lc_number, e->lc_new_number, e->refcnt);
663                 else
664                         seq_printf(seq, "\t%5d: %6d %-8s %6d ",
665                                 i, e->lc_number, "-\"-", e->refcnt);
666                 if (detail)
667                         detail(seq, e);
668                 seq_putc(seq, '\n');
669         }
670 }
671 
672 EXPORT_SYMBOL(lc_create);
673 EXPORT_SYMBOL(lc_reset);
674 EXPORT_SYMBOL(lc_destroy);
675 EXPORT_SYMBOL(lc_set);
676 EXPORT_SYMBOL(lc_del);
677 EXPORT_SYMBOL(lc_try_get);
678 EXPORT_SYMBOL(lc_find);
679 EXPORT_SYMBOL(lc_get);
680 EXPORT_SYMBOL(lc_put);
681 EXPORT_SYMBOL(lc_committed);
682 EXPORT_SYMBOL(lc_element_by_index);
683 EXPORT_SYMBOL(lc_index_of);
684 EXPORT_SYMBOL(lc_seq_printf_stats);
685 EXPORT_SYMBOL(lc_seq_dump_details);
686 EXPORT_SYMBOL(lc_try_lock);
687 EXPORT_SYMBOL(lc_is_used);
688 EXPORT_SYMBOL(lc_get_cumulative);
689 

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