fs/btrfs/lru_cache.c

8  * Initialize a cache object.
10  * @cache:      The cache.
11  * @max_size:   Maximum size (number of entries) for the cache.
13  *              trim the cache in that case.
15 void btrfs_lru_cache_init(struct btrfs_lru_cache *cache, unsigned int max_size)
17 	INIT_LIST_HEAD(&cache->lru_list);
18 	mt_init(&cache->entries);
19 	cache->size = 0;
20 	cache->max_size = max_size;
37  * Lookup for an entry in the cache.
39  * @cache:      The cache.
45 struct btrfs_lru_cache_entry *btrfs_lru_cache_lookup(struct btrfs_lru_cache *cache,
51 	head = mtree_load(&cache->entries, key);
57 		list_move_tail(&entry->lru_list, &cache->lru_list);
63  * Remove an entry from the cache.
65  * @cache:     The cache to remove from.
66  * @entry:     The entry to remove from the cache.
70 void btrfs_lru_cache_remove(struct btrfs_lru_cache *cache,
75 	ASSERT(cache->size > 0);
76 	ASSERT(!mtree_empty(&cache->entries));
89 		head = mtree_erase(&cache->entries, entry->key);
95 	cache->size--;
99  * Store an entry in the cache.
101  * @cache:      The cache.
106 int btrfs_lru_cache_store(struct btrfs_lru_cache *cache,
118 	ret = mtree_insert(&cache->entries, key, head, gfp);
124 		head = mtree_load(&cache->entries, key);
134 	if (cache->max_size > 0 && cache->size == cache->max_size) {
137 		lru_entry = list_first_entry(&cache->lru_list,
140 		btrfs_lru_cache_remove(cache, lru_entry);
143 	list_add_tail(&new_entry->lru_list, &cache->lru_list);
144 	cache->size++;
150  * Empty a cache.
152  * @cache:     The cache to empty.
154  * Removes all entries from the cache.
156 void btrfs_lru_cache_clear(struct btrfs_lru_cache *cache)
161 	list_for_each_entry_safe(entry, tmp, &cache->lru_list, lru_list)
162 		btrfs_lru_cache_remove(cache, entry);
164 	ASSERT(cache->size == 0);
165 	ASSERT(mtree_empty(&cache->entries));