struct mb_cache {
struct list_head c_cache_list;
const char *c_name;
- struct mb_cache_op c_op;
atomic_t c_entry_count;
+ int c_max_entries;
int c_bucket_bits;
-#ifndef MB_CACHE_INDEXES_COUNT
- int c_indexes_count;
-#endif
- struct kmem_cache *c_entry_cache;
+ struct kmem_cache *c_entry_cache;
struct list_head *c_block_hash;
- struct list_head *c_indexes_hash[0];
+ struct list_head *c_index_hash;
};
static LIST_HEAD(mb_cache_lru_list);
static DEFINE_SPINLOCK(mb_cache_spinlock);
-static inline int
-mb_cache_indexes(struct mb_cache *cache)
-{
-#ifdef MB_CACHE_INDEXES_COUNT
- return MB_CACHE_INDEXES_COUNT;
-#else
- return cache->c_indexes_count;
-#endif
-}
-
/*
* What the mbcache registers as to get shrunk dynamically.
*/
static void
__mb_cache_entry_unhash(struct mb_cache_entry *ce)
{
- int n;
-
if (__mb_cache_entry_is_hashed(ce)) {
list_del_init(&ce->e_block_list);
- for (n=0; n<mb_cache_indexes(ce->e_cache); n++)
- list_del(&ce->e_indexes[n].o_list);
+ list_del(&ce->e_index.o_list);
}
}
struct mb_cache *cache = ce->e_cache;
mb_assert(!(ce->e_used || ce->e_queued));
- if (cache->c_op.free && cache->c_op.free(ce, gfp_mask)) {
- /* free failed -- put back on the lru list
- for freeing later. */
- spin_lock(&mb_cache_spinlock);
- list_add(&ce->e_lru_list, &mb_cache_lru_list);
- spin_unlock(&mb_cache_spinlock);
- } else {
- kmem_cache_free(cache->c_entry_cache, ce);
- atomic_dec(&cache->c_entry_count);
- }
+ kmem_cache_free(cache->c_entry_cache, ce);
+ atomic_dec(&cache->c_entry_count);
}
mb_cache_shrink_fn(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
{
LIST_HEAD(free_list);
- struct list_head *l, *ltmp;
+ struct mb_cache *cache;
+ struct mb_cache_entry *entry, *tmp;
int count = 0;
- spin_lock(&mb_cache_spinlock);
- list_for_each(l, &mb_cache_list) {
- struct mb_cache *cache =
- list_entry(l, struct mb_cache, c_cache_list);
- mb_debug("cache %s (%d)", cache->c_name,
- atomic_read(&cache->c_entry_count));
- count += atomic_read(&cache->c_entry_count);
- }
mb_debug("trying to free %d entries", nr_to_scan);
- if (nr_to_scan == 0) {
- spin_unlock(&mb_cache_spinlock);
- goto out;
- }
+ spin_lock(&mb_cache_spinlock);
while (nr_to_scan-- && !list_empty(&mb_cache_lru_list)) {
struct mb_cache_entry *ce =
list_entry(mb_cache_lru_list.next,
list_move_tail(&ce->e_lru_list, &free_list);
__mb_cache_entry_unhash(ce);
}
+ list_for_each_entry(cache, &mb_cache_list, c_cache_list) {
+ mb_debug("cache %s (%d)", cache->c_name,
+ atomic_read(&cache->c_entry_count));
+ count += atomic_read(&cache->c_entry_count);
+ }
spin_unlock(&mb_cache_spinlock);
- list_for_each_safe(l, ltmp, &free_list) {
- __mb_cache_entry_forget(list_entry(l, struct mb_cache_entry,
- e_lru_list), gfp_mask);
+ list_for_each_entry_safe(entry, tmp, &free_list, e_lru_list) {
+ __mb_cache_entry_forget(entry, gfp_mask);
}
-out:
return (count / 100) * sysctl_vfs_cache_pressure;
}
* memory was available.
*
* @name: name of the cache (informal)
- * @cache_op: contains the callback called when freeing a cache entry
- * @entry_size: The size of a cache entry, including
- * struct mb_cache_entry
- * @indexes_count: number of additional indexes in the cache. Must equal
- * MB_CACHE_INDEXES_COUNT if the number of indexes is
- * hardwired.
* @bucket_bits: log2(number of hash buckets)
*/
struct mb_cache *
-mb_cache_create(const char *name, struct mb_cache_op *cache_op,
- size_t entry_size, int indexes_count, int bucket_bits)
+mb_cache_create(const char *name, int bucket_bits)
{
- int m=0, n, bucket_count = 1 << bucket_bits;
+ int n, bucket_count = 1 << bucket_bits;
struct mb_cache *cache = NULL;
- if(entry_size < sizeof(struct mb_cache_entry) +
- indexes_count * sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]))
- return NULL;
-
- cache = kmalloc(sizeof(struct mb_cache) +
- indexes_count * sizeof(struct list_head), GFP_KERNEL);
+ cache = kmalloc(sizeof(struct mb_cache), GFP_KERNEL);
if (!cache)
- goto fail;
+ return NULL;
cache->c_name = name;
- cache->c_op.free = NULL;
- if (cache_op)
- cache->c_op.free = cache_op->free;
atomic_set(&cache->c_entry_count, 0);
cache->c_bucket_bits = bucket_bits;
-#ifdef MB_CACHE_INDEXES_COUNT
- mb_assert(indexes_count == MB_CACHE_INDEXES_COUNT);
-#else
- cache->c_indexes_count = indexes_count;
-#endif
cache->c_block_hash = kmalloc(bucket_count * sizeof(struct list_head),
GFP_KERNEL);
if (!cache->c_block_hash)
goto fail;
for (n=0; n<bucket_count; n++)
INIT_LIST_HEAD(&cache->c_block_hash[n]);
- for (m=0; m<indexes_count; m++) {
- cache->c_indexes_hash[m] = kmalloc(bucket_count *
- sizeof(struct list_head),
- GFP_KERNEL);
- if (!cache->c_indexes_hash[m])
- goto fail;
- for (n=0; n<bucket_count; n++)
- INIT_LIST_HEAD(&cache->c_indexes_hash[m][n]);
- }
- cache->c_entry_cache = kmem_cache_create(name, entry_size, 0,
+ cache->c_index_hash = kmalloc(bucket_count * sizeof(struct list_head),
+ GFP_KERNEL);
+ if (!cache->c_index_hash)
+ goto fail;
+ for (n=0; n<bucket_count; n++)
+ INIT_LIST_HEAD(&cache->c_index_hash[n]);
+ cache->c_entry_cache = kmem_cache_create(name,
+ sizeof(struct mb_cache_entry), 0,
SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL);
if (!cache->c_entry_cache)
- goto fail;
+ goto fail2;
+
+ /*
+ * Set an upper limit on the number of cache entries so that the hash
+ * chains won't grow too long.
+ */
+ cache->c_max_entries = bucket_count << 4;
spin_lock(&mb_cache_spinlock);
list_add(&cache->c_cache_list, &mb_cache_list);
spin_unlock(&mb_cache_spinlock);
return cache;
+fail2:
+ kfree(cache->c_index_hash);
+
fail:
- if (cache) {
- while (--m >= 0)
- kfree(cache->c_indexes_hash[m]);
- kfree(cache->c_block_hash);
- kfree(cache);
- }
+ kfree(cache->c_block_hash);
+ kfree(cache);
return NULL;
}
{
LIST_HEAD(free_list);
struct list_head *l, *ltmp;
- int n;
spin_lock(&mb_cache_spinlock);
list_for_each_safe(l, ltmp, &mb_cache_lru_list) {
kmem_cache_destroy(cache->c_entry_cache);
- for (n=0; n < mb_cache_indexes(cache); n++)
- kfree(cache->c_indexes_hash[n]);
+ kfree(cache->c_index_hash);
kfree(cache->c_block_hash);
kfree(cache);
}
-
/*
* mb_cache_entry_alloc()
*
struct mb_cache_entry *
mb_cache_entry_alloc(struct mb_cache *cache, gfp_t gfp_flags)
{
- struct mb_cache_entry *ce;
+ struct mb_cache_entry *ce = NULL;
- ce = kmem_cache_alloc(cache->c_entry_cache, gfp_flags);
- if (ce) {
+ if (atomic_read(&cache->c_entry_count) >= cache->c_max_entries) {
+ spin_lock(&mb_cache_spinlock);
+ if (!list_empty(&mb_cache_lru_list)) {
+ ce = list_entry(mb_cache_lru_list.next,
+ struct mb_cache_entry, e_lru_list);
+ list_del_init(&ce->e_lru_list);
+ __mb_cache_entry_unhash(ce);
+ }
+ spin_unlock(&mb_cache_spinlock);
+ }
+ if (!ce) {
+ ce = kmem_cache_alloc(cache->c_entry_cache, gfp_flags);
+ if (!ce)
+ return NULL;
atomic_inc(&cache->c_entry_count);
INIT_LIST_HEAD(&ce->e_lru_list);
INIT_LIST_HEAD(&ce->e_block_list);
ce->e_cache = cache;
- ce->e_used = 1 + MB_CACHE_WRITER;
ce->e_queued = 0;
}
+ ce->e_used = 1 + MB_CACHE_WRITER;
return ce;
}
*
* @bdev: device the cache entry belongs to
* @block: block number
- * @keys: array of additional keys. There must be indexes_count entries
- * in the array (as specified when creating the cache).
+ * @key: lookup key
*/
int
mb_cache_entry_insert(struct mb_cache_entry *ce, struct block_device *bdev,
- sector_t block, unsigned int keys[])
+ sector_t block, unsigned int key)
{
struct mb_cache *cache = ce->e_cache;
unsigned int bucket;
struct list_head *l;
- int error = -EBUSY, n;
+ int error = -EBUSY;
bucket = hash_long((unsigned long)bdev + (block & 0xffffffff),
cache->c_bucket_bits);
ce->e_bdev = bdev;
ce->e_block = block;
list_add(&ce->e_block_list, &cache->c_block_hash[bucket]);
- for (n=0; n<mb_cache_indexes(cache); n++) {
- ce->e_indexes[n].o_key = keys[n];
- bucket = hash_long(keys[n], cache->c_bucket_bits);
- list_add(&ce->e_indexes[n].o_list,
- &cache->c_indexes_hash[n][bucket]);
- }
+ ce->e_index.o_key = key;
+ bucket = hash_long(key, cache->c_bucket_bits);
+ list_add(&ce->e_index.o_list, &cache->c_index_hash[bucket]);
error = 0;
out:
spin_unlock(&mb_cache_spinlock);
static struct mb_cache_entry *
__mb_cache_entry_find(struct list_head *l, struct list_head *head,
- int index, struct block_device *bdev, unsigned int key)
+ struct block_device *bdev, unsigned int key)
{
while (l != head) {
struct mb_cache_entry *ce =
- list_entry(l, struct mb_cache_entry,
- e_indexes[index].o_list);
- if (ce->e_bdev == bdev && ce->e_indexes[index].o_key == key) {
+ list_entry(l, struct mb_cache_entry, e_index.o_list);
+ if (ce->e_bdev == bdev && ce->e_index.o_key == key) {
DEFINE_WAIT(wait);
if (!list_empty(&ce->e_lru_list))
* returned cache entry is locked for shared access ("multiple readers").
*
* @cache: the cache to search
- * @index: the number of the additonal index to search (0<=index<indexes_count)
* @bdev: the device the cache entry should belong to
* @key: the key in the index
*/
struct mb_cache_entry *
-mb_cache_entry_find_first(struct mb_cache *cache, int index,
- struct block_device *bdev, unsigned int key)
+mb_cache_entry_find_first(struct mb_cache *cache, struct block_device *bdev,
+ unsigned int key)
{
unsigned int bucket = hash_long(key, cache->c_bucket_bits);
struct list_head *l;
struct mb_cache_entry *ce;
- mb_assert(index < mb_cache_indexes(cache));
spin_lock(&mb_cache_spinlock);
- l = cache->c_indexes_hash[index][bucket].next;
- ce = __mb_cache_entry_find(l, &cache->c_indexes_hash[index][bucket],
- index, bdev, key);
+ l = cache->c_index_hash[bucket].next;
+ ce = __mb_cache_entry_find(l, &cache->c_index_hash[bucket], bdev, key);
spin_unlock(&mb_cache_spinlock);
return ce;
}
* }
*
* @prev: The previous match
- * @index: the number of the additonal index to search (0<=index<indexes_count)
* @bdev: the device the cache entry should belong to
* @key: the key in the index
*/
struct mb_cache_entry *
-mb_cache_entry_find_next(struct mb_cache_entry *prev, int index,
+mb_cache_entry_find_next(struct mb_cache_entry *prev,
struct block_device *bdev, unsigned int key)
{
struct mb_cache *cache = prev->e_cache;
struct list_head *l;
struct mb_cache_entry *ce;
- mb_assert(index < mb_cache_indexes(cache));
spin_lock(&mb_cache_spinlock);
- l = prev->e_indexes[index].o_list.next;
- ce = __mb_cache_entry_find(l, &cache->c_indexes_hash[index][bucket],
- index, bdev, key);
+ l = prev->e_index.o_list.next;
+ ce = __mb_cache_entry_find(l, &cache->c_index_hash[bucket], bdev, key);
__mb_cache_entry_release_unlock(prev);
return ce;
}
git://bbs.cooldavid.org / net-next-2.6.git / blobdiff