diff options
| -rw-r--r-- | drivers/block/drbd/drbd_actlog.c | 50 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_nl.c | 4 | ||||
| -rw-r--r-- | include/linux/lru_cache.h | 68 | ||||
| -rw-r--r-- | lib/lru_cache.c | 243 |
4 files changed, 225 insertions, 140 deletions
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c index 1ce3de6eed1b..44097c87fed7 100644 --- a/drivers/block/drbd/drbd_actlog.c +++ b/drivers/block/drbd/drbd_actlog.c @@ -175,7 +175,6 @@ static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr) { struct lc_element *al_ext; struct lc_element *tmp; - unsigned long al_flags = 0; int wake; spin_lock_irq(&mdev->al_lock); @@ -190,19 +189,8 @@ static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr) return NULL; } } - al_ext = lc_get(mdev->act_log, enr); - al_flags = mdev->act_log->flags; + al_ext = lc_get(mdev->act_log, enr); spin_unlock_irq(&mdev->al_lock); - - /* - if (!al_ext) { - if (al_flags & LC_STARVING) - dev_warn(DEV, "Have to wait for LRU element (AL too small?)\n"); - if (al_flags & LC_DIRTY) - dev_warn(DEV, "Ongoing AL update (AL device too slow?)\n"); - } - */ - return al_ext; } @@ -235,7 +223,7 @@ void drbd_al_begin_io(struct drbd_conf *mdev, sector_t sector) mdev->al_writ_cnt++; spin_lock_irq(&mdev->al_lock); - lc_changed(mdev->act_log, al_ext); + lc_committed(mdev->act_log); spin_unlock_irq(&mdev->al_lock); wake_up(&mdev->al_wait); } @@ -601,7 +589,7 @@ void drbd_al_shrink(struct drbd_conf *mdev) struct lc_element *al_ext; int i; - D_ASSERT(test_bit(__LC_DIRTY, &mdev->act_log->flags)); + D_ASSERT(test_bit(__LC_LOCKED, &mdev->act_log->flags)); for (i = 0; i < mdev->act_log->nr_elements; i++) { al_ext = lc_element_by_index(mdev->act_log, i); @@ -708,7 +696,9 @@ static void drbd_try_clear_on_disk_bm(struct drbd_conf *mdev, sector_t sector, } ext->rs_left = rs_left; ext->rs_failed = success ? 0 : count; - lc_changed(mdev->resync, &ext->lce); + /* we don't keep a persistent log of the resync lru, + * we can commit any change right away. */ + lc_committed(mdev->resync); } lc_put(mdev->resync, &ext->lce); /* no race, we are within the al_lock! */ @@ -892,7 +882,7 @@ struct bm_extent *_bme_get(struct drbd_conf *mdev, unsigned int enr) if (bm_ext->lce.lc_number != enr) { bm_ext->rs_left = drbd_bm_e_weight(mdev, enr); bm_ext->rs_failed = 0; - lc_changed(mdev->resync, &bm_ext->lce); + lc_committed(mdev->resync); wakeup = 1; } if (bm_ext->lce.refcnt == 1) @@ -908,7 +898,7 @@ struct bm_extent *_bme_get(struct drbd_conf *mdev, unsigned int enr) if (rs_flags & LC_STARVING) dev_warn(DEV, "Have to wait for element" " (resync LRU too small?)\n"); - BUG_ON(rs_flags & LC_DIRTY); + BUG_ON(rs_flags & LC_LOCKED); } return bm_ext; @@ -916,26 +906,12 @@ struct bm_extent *_bme_get(struct drbd_conf *mdev, unsigned int enr) static int _is_in_al(struct drbd_conf *mdev, unsigned int enr) { - struct lc_element *al_ext; - int rv = 0; + int rv; spin_lock_irq(&mdev->al_lock); - if (unlikely(enr == mdev->act_log->new_number)) - rv = 1; - else { - al_ext = lc_find(mdev->act_log, enr); - if (al_ext) { - if (al_ext->refcnt) - rv = 1; - } - } + rv = lc_is_used(mdev->act_log, enr); spin_unlock_irq(&mdev->al_lock); - /* - if (unlikely(rv)) { - dev_info(DEV, "Delaying sync read until app's write is done\n"); - } - */ return rv; } @@ -1065,13 +1041,13 @@ int drbd_try_rs_begin_io(struct drbd_conf *mdev, sector_t sector) if (rs_flags & LC_STARVING) dev_warn(DEV, "Have to wait for element" " (resync LRU too small?)\n"); - BUG_ON(rs_flags & LC_DIRTY); + BUG_ON(rs_flags & LC_LOCKED); goto try_again; } if (bm_ext->lce.lc_number != enr) { bm_ext->rs_left = drbd_bm_e_weight(mdev, enr); bm_ext->rs_failed = 0; - lc_changed(mdev->resync, &bm_ext->lce); + lc_committed(mdev->resync); wake_up(&mdev->al_wait); D_ASSERT(test_bit(BME_LOCKED, &bm_ext->flags) == 0); } @@ -1082,8 +1058,6 @@ int drbd_try_rs_begin_io(struct drbd_conf *mdev, sector_t sector) } check_al: for (i = 0; i < AL_EXT_PER_BM_SECT; i++) { - if (unlikely(al_enr+i == mdev->act_log->new_number)) - goto try_again; if (lc_is_used(mdev->act_log, al_enr+i)) goto try_again; } diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index ae8f42e38e4f..0a92f5226c2a 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -760,7 +760,7 @@ static int drbd_check_al_size(struct drbd_conf *mdev) in_use = 0; t = mdev->act_log; - n = lc_create("act_log", drbd_al_ext_cache, + n = lc_create("act_log", drbd_al_ext_cache, 1, mdev->sync_conf.al_extents, sizeof(struct lc_element), 0); if (n == NULL) { @@ -1016,7 +1016,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp } resync_lru = lc_create("resync", drbd_bm_ext_cache, - 61, sizeof(struct bm_extent), + 1, 61, sizeof(struct bm_extent), offsetof(struct bm_extent, lce)); if (!resync_lru) { retcode = ERR_NOMEM; diff --git a/include/linux/lru_cache.h b/include/linux/lru_cache.h index 4cceafb0732d..cbafae40c649 100644 --- a/include/linux/lru_cache.h +++ b/include/linux/lru_cache.h @@ -166,9 +166,11 @@ struct lc_element { /* if we want to track a larger set of objects, * it needs to become arch independend u64 */ unsigned lc_number; - /* special label when on free list */ #define LC_FREE (~0U) + + /* for pending changes */ + unsigned lc_new_number; }; struct lru_cache { @@ -176,6 +178,7 @@ struct lru_cache { struct list_head lru; struct list_head free; struct list_head in_use; + struct list_head to_be_changed; /* the pre-created kmem cache to allocate the objects from */ struct kmem_cache *lc_cache; @@ -186,7 +189,7 @@ struct lru_cache { size_t element_off; /* number of elements (indices) */ - unsigned int nr_elements; + unsigned int nr_elements; /* Arbitrary limit on maximum tracked objects. Practical limit is much * lower due to allocation failures, probably. For typical use cases, * nr_elements should be a few thousand at most. @@ -194,18 +197,19 @@ struct lru_cache { * 8 high bits of .lc_index to be overloaded with flags in the future. */ #define LC_MAX_ACTIVE (1<<24) + /* allow to accumulate a few (index:label) changes, + * but no more than max_pending_changes */ + unsigned int max_pending_changes; + /* number of elements currently on to_be_changed list */ + unsigned int pending_changes; + /* statistics */ - unsigned used; /* number of lelements currently on in_use list */ - unsigned long hits, misses, starving, dirty, changed; + unsigned used; /* number of elements currently on in_use list */ + unsigned long hits, misses, starving, locked, changed; /* see below: flag-bits for lru_cache */ unsigned long flags; - /* when changing the label of an index element */ - unsigned int new_number; - - /* for paranoia when changing the label of an index element */ - struct lc_element *changing_element; void *lc_private; const char *name; @@ -221,10 +225,15 @@ enum { /* debugging aid, to catch concurrent access early. * user needs to guarantee exclusive access by proper locking! */ __LC_PARANOIA, - /* if we need to change the set, but currently there is a changing - * transaction pending, we are "dirty", and must deferr further - * changing requests */ + + /* annotate that the set is "dirty", possibly accumulating further + * changes, until a transaction is finally triggered */ __LC_DIRTY, + + /* Locked, no further changes allowed. + * Also used to serialize changing transactions. */ + __LC_LOCKED, + /* if we need to change the set, but currently there is no free nor * unused element available, we are "starving", and must not give out * further references, to guarantee that eventually some refcnt will @@ -236,9 +245,11 @@ enum { }; #define LC_PARANOIA (1<<__LC_PARANOIA) #define LC_DIRTY (1<<__LC_DIRTY) +#define LC_LOCKED (1<<__LC_LOCKED) #define LC_STARVING (1<<__LC_STARVING) extern struct lru_cache *lc_create(const char *name, struct kmem_cache *cache, + unsigned max_pending_changes, unsigned e_count, size_t e_size, size_t e_off); extern void lc_reset(struct lru_cache *lc); extern void lc_destroy(struct lru_cache *lc); @@ -249,7 +260,7 @@ extern struct lc_element *lc_try_get(struct lru_cache *lc, unsigned int enr); extern struct lc_element *lc_find(struct lru_cache *lc, unsigned int enr); extern struct lc_element *lc_get(struct lru_cache *lc, unsigned int enr); extern unsigned int lc_put(struct lru_cache *lc, struct lc_element *e); -extern void lc_changed(struct lru_cache *lc, struct lc_element *e); +extern void lc_committed(struct lru_cache *lc); struct seq_file; extern size_t lc_seq_printf_stats(struct seq_file *seq, struct lru_cache *lc); @@ -258,31 +269,40 @@ extern void lc_seq_dump_details(struct seq_file *seq, struct lru_cache *lc, char void (*detail) (struct seq_file *, struct lc_element *)); /** - * lc_try_lock - can be used to stop lc_get() from changing the tracked set + * lc_try_lock_for_transaction - can be used to stop lc_get() from changing the tracked set * @lc: the lru cache to operate on * - * Note that the reference counts and order on the active and lru lists may - * still change. Returns true if we acquired the lock. + * Allows (expects) the set to be "dirty". Note that the reference counts and + * order on the active and lru lists may still change. Used to serialize + * changing transactions. Returns true if we aquired the lock. */ -static inline int lc_try_lock(struct lru_cache *lc) +static inline int lc_try_lock_for_transaction(struct lru_cache *lc) { - return !test_and_set_bit(__LC_DIRTY, &lc->flags); + return !test_and_set_bit(__LC_LOCKED, &lc->flags); } /** + * lc_try_lock - variant to stop lc_get() from changing the tracked set + * @lc: the lru cache to operate on + * + * Note that the reference counts and order on the active and lru lists may + * still change. Only works on a "clean" set. Returns true if we aquired the + * lock, which means there are no pending changes, and any further attempt to + * change the set will not succeed until the next lc_unlock(). + */ +extern int lc_try_lock(struct lru_cache *lc); + +/** * lc_unlock - unlock @lc, allow lc_get() to change the set again * @lc: the lru cache to operate on */ static inline void lc_unlock(struct lru_cache *lc) { - clear_bit_unlock(__LC_DIRTY, &lc->flags); + clear_bit(__LC_DIRTY, &lc->flags); + clear_bit_unlock(__LC_LOCKED, &lc->flags); } -static inline int lc_is_used(struct lru_cache *lc, unsigned int enr) -{ - struct lc_element *e = lc_find(lc, enr); - return e && e->refcnt; -} +extern bool lc_is_used(struct lru_cache *lc, unsigned int enr); #define lc_entry(ptr, type, member) \ container_of(ptr, type, member) diff --git a/lib/lru_cache.c b/lib/lru_cache.c index 17621684758a..d71d89498943 100644 --- a/lib/lru_cache.c +++ b/lib/lru_cache.c @@ -55,9 +55,40 @@ MODULE_LICENSE("GPL"); BUG_ON(i >= lc_->nr_elements); \ BUG_ON(lc_->lc_element[i] != e_); } while (0) + +/* We need to atomically + * - try to grab the lock (set LC_LOCKED) + * - only if there is no pending transaction + * (neither LC_DIRTY nor LC_STARVING is set) + * Because of PARANOIA_ENTRY() above abusing lc->flags as well, + * it is not sufficient to just say + * return 0 == cmpxchg(&lc->flags, 0, LC_LOCKED); + */ +int lc_try_lock(struct lru_cache *lc) +{ + unsigned long val; + do { + val = cmpxchg(&lc->flags, 0, LC_LOCKED); + } while (unlikely (val == LC_PARANOIA)); + /* Spin until no-one is inside a PARANOIA_ENTRY()/RETURN() section. */ + return 0 == val; +#if 0 + /* Alternative approach, spin in case someone enters or leaves a + * PARANOIA_ENTRY()/RETURN() section. */ + unsigned long old, new, val; + do { + old = lc->flags & LC_PARANOIA; + new = old | LC_LOCKED; + val = cmpxchg(&lc->flags, old, new); + } while (unlikely (val == (old ^ LC_PARANOIA))); + return old == val; +#endif +} + /** * lc_create - prepares to track objects in an active set * @name: descriptive name only used in lc_seq_printf_stats and lc_seq_dump_details + * @max_pending_changes: maximum changes to accumulate until a transaction is required * @e_count: number of elements allowed to be active simultaneously * @e_size: size of the tracked objects * @e_off: offset to the &struct lc_element member in a tracked object @@ -66,6 +97,7 @@ MODULE_LICENSE("GPL"); * or NULL on (allocation) failure. */ struct lru_cache *lc_create(const char *name, struct kmem_cache *cache, + unsigned max_pending_changes, unsigned e_count, size_t e_size, size_t e_off) { struct hlist_head *slot = NULL; @@ -98,12 +130,13 @@ struct lru_cache *lc_create(const char *name, struct kmem_cache *cache, INIT_LIST_HEAD(&lc->in_use); INIT_LIST_HEAD(&lc->lru); INIT_LIST_HEAD(&lc->free); + INIT_LIST_HEAD(&lc->to_be_changed); lc->name = name; lc->element_size = e_size; lc->element_off = e_off; lc->nr_elements = e_count; - lc->new_number = LC_FREE; + lc->max_pending_changes = max_pending_changes; lc->lc_cache = cache; lc->lc_element = element; lc->lc_slot = slot; @@ -117,6 +150,7 @@ struct lru_cache *lc_create(const char *name, struct kmem_cache *cache, e = p + e_off; e->lc_index = i; e->lc_number = LC_FREE; + e->lc_new_number = LC_FREE; list_add(&e->list, &lc->free); element[i] = e; } @@ -175,15 +209,15 @@ void lc_reset(struct lru_cache *lc) INIT_LIST_HEAD(&lc->in_use); INIT_LIST_HEAD(&lc->lru); INIT_LIST_HEAD(&lc->free); + INIT_LIST_HEAD(&lc->to_be_changed); lc->used = 0; lc->hits = 0; lc->misses = 0; lc->starving = 0; - lc->dirty = 0; + lc->locked = 0; lc->changed = 0; + lc->pending_changes = 0; lc->flags = 0; - lc->changing_element = NULL; - lc->new_number = LC_FREE; memset(lc->lc_slot, 0, sizeof(struct hlist_head) * lc->nr_elements); for (i = 0; i < lc->nr_elements; i++) { @@ -194,6 +228,7 @@ void lc_reset(struct lru_cache *lc) /* re-init it */ e->lc_index = i; e->lc_number = LC_FREE; + e->lc_new_number = LC_FREE; list_add(&e->list, &lc->free); } } @@ -208,14 +243,14 @@ size_t lc_seq_printf_stats(struct seq_file *seq, struct lru_cache *lc) /* NOTE: * total calls to lc_get are * (starving + hits + misses) - * misses include "dirty" count (update from an other thread in + * misses include "locked" count (update from an other thread in * progress) and "changed", when this in fact lead to an successful * update of the cache. */ return seq_printf(seq, "\t%s: used:%u/%u " - "hits:%lu misses:%lu starving:%lu dirty:%lu changed:%lu\n", + "hits:%lu misses:%lu starving:%lu locked:%lu changed:%lu\n", lc->name, lc->used, lc->nr_elements, - lc->hits, lc->misses, lc->starving, lc->dirty, lc->changed); + lc->hits, lc->misses, lc->starving, lc->locked, lc->changed); } static struct hlist_head *lc_hash_slot(struct lru_cache *lc, unsigned int enr) @@ -224,16 +259,8 @@ static struct hlist_head *lc_hash_slot(struct lru_cache *lc, unsigned int enr) } -/** - * lc_find - find element by label, if present in the hash table - * @lc: The lru_cache object - * @enr: element number - * - * Returns the pointer to an element, if the element with the requested - * "label" or element number is present in the hash table, - * or NULL if not found. Does not change the refcnt. - */ -struct lc_element *lc_find(struct lru_cache *lc, unsigned int enr) +static struct lc_element *__lc_find(struct lru_cache *lc, unsigned int enr, + bool include_changing) { struct hlist_node *n; struct lc_element *e; @@ -241,29 +268,48 @@ struct lc_element *lc_find(struct lru_cache *lc, unsigned int enr) BUG_ON(!lc); BUG_ON(!lc->nr_elements); hlist_for_each_entry(e, n, lc_hash_slot(lc, enr), colision) { - if (e->lc_number == enr) + /* "about to be changed" elements, pending transaction commit, + * are hashed by their "new number". "Normal" elements have + * lc_number == lc_new_number. */ + if (e->lc_new_number != enr) + continue; + if (e->lc_new_number == e->lc_number || include_changing) return e; + break; } return NULL; } -/* returned element will be "recycled" immediately */ -static struct lc_element *lc_evict(struct lru_cache *lc) +/** + * lc_find - find element by label, if present in the hash table + * @lc: The lru_cache object + * @enr: element number + * + * Returns the pointer to an element, if the element with the requested + * "label" or element number is present in the hash table, + * or NULL if not found. Does not change the refcnt. + * Ignores elements that are "about to be used", i.e. not yet in the active + * set, but still pending transaction commit. + */ +struct lc_element *lc_find(struct lru_cache *lc, unsigned int enr) { - struct list_head *n; - struct lc_element *e; - - if (list_empty(&lc->lru)) - return NULL; - - n = lc->lru.prev; - e = list_entry(n, struct lc_element, list); - - PARANOIA_LC_ELEMENT(lc, e); + return __lc_find(lc, enr, 0); +} - list_del(&e->list); - hlist_del(&e->colision); - return e; +/** + * lc_is_used - find element by label + * @lc: The lru_cache object + * @enr: element number + * + * Returns true, if the element with the requested "label" or element number is + * present in the hash table, and is used (refcnt > 0). + * Also finds elements that are not _currently_ used but only "about to be + * used", i.e. on the "to_be_changed" list, pending transaction commit. + */ +bool lc_is_used(struct lru_cache *lc, unsigned int enr) +{ + struct lc_element *e = __lc_find(lc, enr, 1); + return e && e->refcnt; } /** @@ -280,22 +326,34 @@ void lc_del(struct lru_cache *lc, struct lc_element *e) PARANOIA_LC_ELEMENT(lc, e); BUG_ON(e->refcnt); - e->lc_number = LC_FREE; + e->lc_number = e->lc_new_number = LC_FREE; hlist_del_init(&e->colision); list_move(&e->list, &lc->free); RETURN(); } -static struct lc_element *lc_get_unused_element(struct lru_cache *lc) +static struct lc_element *lc_prepare_for_change(struct lru_cache *lc, unsigned new_number) { struct list_head *n; + struct lc_element *e; + + if (!list_empty(&lc->free)) + n = lc->free.next; + else if (!list_empty(&lc->lru)) + n = lc->lru.prev; + else + return NULL; + + e = list_entry(n, struct lc_element, list); + PARANOIA_LC_ELEMENT(lc, e); - if (list_empty(&lc->free)) - return lc_evict(lc); + e->lc_new_number = new_number; + if (!hlist_unhashed(&e->colision)) + __hlist_del(&e->colision); + hlist_add_head(&e->colision, lc_hash_slot(lc, new_number)); + list_move(&e->list, &lc->to_be_changed); - n = lc->free.next; - list_del(n); - return list_entry(n, struct lc_element, list); + return e; } static int lc_unused_element_available(struct lru_cache *lc) @@ -318,8 +376,12 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, bool RETURN(NULL); } - e = lc_find(lc, enr); - if (e) { + e = __lc_find(lc, enr, 1); + /* if lc_new_number != lc_number, + * this enr is currently being pulled in already, + * and will be available once the pending transaction + * has been committed. */ + if (e && e->lc_new_number == e->lc_number) { ++lc->hits; if (e->refcnt++ == 0) lc->used++; @@ -331,6 +393,24 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, bool if (!may_change) RETURN(NULL); + /* It has been found above, but on the "to_be_changed" list, not yet + * committed. Don't pull it in twice, wait for the transaction, then + * try again */ + if (e) + RETURN(NULL); + + /* To avoid races with lc_try_lock(), first, mark us dirty + * (using test_and_set_bit, as it implies memory barriers), ... */ + test_and_set_bit(__LC_DIRTY, &lc->flags); + + /* ... only then check if it is locked anyways. If lc_unlock clears + * the dirty bit again, that's not a problem, we will come here again. + */ + if (test_bit(__LC_LOCKED, &lc->flags)) { + ++lc->locked; + RETURN(NULL); + } + /* In case there is nothing available and we can not kick out * the LRU element, we have to wait ... */ @@ -339,24 +419,19 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, bool RETURN(NULL); } - /* it was not present in the active set. - * we are going to recycle an unused (or even "free") element. - * user may need to commit a transaction to record that change. - * we serialize on flags & LC_DIRTY */ - if (test_and_set_bit(__LC_DIRTY, &lc->flags)) { - ++lc->dirty; + /* It was not present in the active set. We are going to recycle an + * unused (or even "free") element, but we won't accumulate more than + * max_pending_changes changes. */ + if (lc->pending_changes >= lc->max_pending_changes) RETURN(NULL); - } - e = lc_get_unused_element(lc); + e = lc_prepare_for_change(lc, enr); BUG_ON(!e); clear_bit(__LC_STARVING, &lc->flags); BUG_ON(++e->refcnt != 1); lc->used++; - - lc->changing_element = e; - lc->new_number = enr; + lc->pending_changes++; RETURN(e); } @@ -388,12 +463,15 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, bool * pointer to an UNUSED element with some different element number, * where that different number may also be %LC_FREE. * - * In this case, the cache is marked %LC_DIRTY (blocking further changes), - * and the returned element pointer is removed from the lru list and - * hash collision chains. The user now should do whatever housekeeping - * is necessary. - * Then he must call lc_changed(lc,element_pointer), to finish - * the change. + * In this case, the cache is marked %LC_DIRTY, + * so lc_try_lock() will no longer succeed. + * The returned element pointer is moved to the "to_be_changed" list, + * and registered with the new element number on the hash collision chains, + * so it is possible to pick it up from lc_is_used(). + * Up to "max_pending_changes" (see lc_create()) can be accumulated. + * The user now should do whatever housekeeping is necessary, + * typically serialize on lc_try_lock_for_transaction(), then call + * lc_committed(lc) and lc_unlock(), to finish the change. * * NOTE: The user needs to check the lc_number on EACH use, so he recognizes * any cache set change. @@ -425,22 +503,25 @@ struct lc_element *lc_try_get(struct lru_cache *lc, unsigned int enr) } /** - * lc_changed - tell @lc that the change has been recorded + * lc_committed - tell @lc that pending changes have been recorded * @lc: the lru cache to operate on - * @e: the element pending label change + * + * User is expected to serialize on explicit lc_try_lock_for_transaction() + * before the transaction is started, and later needs to lc_unlock() explicitly + * as well. */ -void lc_changed(struct lru_cache *lc, struct lc_element *e) +void lc_committed(struct lru_cache *lc) { + struct lc_element *e, *tmp; + PARANOIA_ENTRY(); - BUG_ON(e != lc->changing_element); - PARANOIA_LC_ELEMENT(lc, e); - ++lc->changed; - e->lc_number = lc->new_number; - list_add(&e->list, &lc->in_use); - hlist_add_head(&e->colision, lc_hash_slot(lc, lc->new_number)); - lc->changing_element = NULL; - lc->new_number = LC_FREE; - clear_bit_unlock(__LC_DIRTY, &lc->flags); + list_for_each_entry_safe(e, tmp, &lc->to_be_changed, list) { + /* count number of changes, not number of transactions */ + ++lc->changed; + e->lc_number = e->lc_new_number; + list_move(&e->list, &lc->in_use); + } + lc->pending_changes = 0; RETURN(); } @@ -459,7 +540,7 @@ unsigned int lc_put(struct lru_cache *lc, struct lc_element *e) PARANOIA_ENTRY(); PARANOIA_LC_ELEMENT(lc, e); BUG_ON(e->refcnt == 0); - BUG_ON(e == lc->changing_element); + BUG_ON(e->lc_number != e->lc_new_number); if (--e->refcnt == 0) { /* move it to the front of LRU. */ list_move(&e->list, &lc->lru); @@ -504,16 +585,24 @@ unsigned int lc_index_of(struct lru_cache *lc, struct lc_element *e) void lc_set(struct lru_cache *lc, unsigned int enr, int index) { struct lc_element *e; + struct list_head *lh; if (index < 0 || index >= lc->nr_elements) return; e = lc_element_by_index(lc, index); - e->lc_number = enr; + BUG_ON(e->lc_number != e->lc_new_number); + BUG_ON(e->refcnt != 0); + e->lc_number = e->lc_new_number = enr; hlist_del_init(&e->colision); - hlist_add_head(&e->colision, lc_hash_slot(lc, enr)); - list_move(&e->list, e->refcnt ? &lc->in_use : &lc->lru); + if (enr == LC_FREE) + lh = &lc->free; + else { + hlist_add_head(&e->colision, lc_hash_slot(lc, enr)); + lh = &lc->lru; + } + list_move(&e->list, lh); } /** @@ -553,8 +642,10 @@ EXPORT_SYMBOL(lc_try_get); EXPORT_SYMBOL(lc_find); EXPORT_SYMBOL(lc_get); EXPORT_SYMBOL(lc_put); -EXPORT_SYMBOL(lc_changed); +EXPORT_SYMBOL(lc_committed); EXPORT_SYMBOL(lc_element_by_index); EXPORT_SYMBOL(lc_index_of); EXPORT_SYMBOL(lc_seq_printf_stats); EXPORT_SYMBOL(lc_seq_dump_details); +EXPORT_SYMBOL(lc_try_lock); +EXPORT_SYMBOL(lc_is_used); |