Fine-grained locking

Create a lock for each entry of a datastructure

Example

/* Fine-grained Locking */
mutex_t bucket[1024]; /* a separate lock for each linked list */
int index = hash(key);
mutex_lock(&bucket[index]);
struct list_head *pos = hash_tbl[index];
/* walk list and find entry */
mutex_unlock(&bucket[index]);

Use when data structure is used often

maximizing concurrency and performance