* 4-bytes boundaries because the two lower bits are used as flags.
*/
+/*
+ * _cds_lfht_node: Contains the internal pointers and reverse-hash
+ * value required for lookup and traversal of the hash table.
+ */
struct _cds_lfht_node {
struct cds_lfht_node *next; /* ptr | DUMMY_FLAG | REMOVED_FLAG */
unsigned long reverse_hash;
} __attribute__((aligned(4)));
/*
+ * cds_lfht_node: Contains the full key and length required to check for
+ * an actual match, and also contains an rcu_head structure that is used
+ * by RCU to track a node through a given RCU grace period. There is an
+ * instance of _cds_lfht_node enclosed as a field within each
+ * _cds_lfht_node structure.
+ *
* struct cds_lfht_node can be embedded into a structure (as a field).
* caa_container_of() can be used to get the structure from the struct
* cds_lfht_node after a lookup.
struct rcu_head head;
};
+/* cds_lfht_iter: Used to track state while traversing a hash chain. */
struct cds_lfht_iter {
struct cds_lfht_node *node, *next;
};
*/
enum {
CDS_LFHT_AUTO_RESIZE = (1U << 0),
+ CDS_LFHT_ACCOUNTING = (1U << 1),
};
/*
cds_lfht_compare_fct compare_fct,
unsigned long hash_seed,
unsigned long init_size,
+ unsigned long min_alloc_size,
int flags,
void (*cds_lfht_call_rcu)(struct rcu_head *head,
void (*func)(struct rcu_head *head)),
* @compare_fct: the key comparison function.
* @hash_seed: the seed for hash function.
* @init_size: number of nodes to allocate initially. Must be power of two.
+ * @min_alloc_size: the smallest allocation size to use. Must be power of two.
* @flags: hash table creation flags (can be combined with bitwise or: '|').
* 0: no flags.
* CDS_LFHT_AUTO_RESIZE: automatically resize hash table.
* this priority level. Having lower priority for call_rcu and resize threads
* does not pose any correctness issue, but the resize operations could be
* starved by updates, thus leading to long hash table bucket chains.
+ * Threads calling this API need to be registered RCU read-side threads.
*/
static inline
struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct,
cds_lfht_compare_fct compare_fct,
unsigned long hash_seed,
unsigned long init_size,
+ unsigned long min_alloc_size,
int flags,
pthread_attr_t *attr)
{
return _cds_lfht_new(hash_fct, compare_fct, hash_seed,
- init_size, flags,
+ init_size, min_alloc_size, flags,
call_rcu, synchronize_rcu, rcu_read_lock,
rcu_read_unlock, rcu_thread_offline,
rcu_thread_online, rcu_register_thread,
* @ht: the hash table to destroy.
* @attr: (output) resize worker thread attributes, as received by cds_lfht_new.
* The caller will typically want to free this pointer if dynamically
- * allocated.
+ * allocated. The attr point can be NULL if the caller does not
+ * need to be informed of the value passed to cds_lfht_new().
*
* Return 0 on success, negative error value on error.
+ * Threads calling this API need to be registered RCU read-side threads.
*/
int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr);
/*
* cds_lfht_count_nodes - count the number of nodes in the hash table.
- *
+ * @ht: the hash table.
+ * @split_count_before: Sample the node count split-counter before traversal.
+ * @count: Traverse the hash table, count the number of nodes observed.
+ * @removed: Number of logically removed nodes observed during traversal.
+ * @split_count_after: Sample the node count split-counter after traversal.
* Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
*/
void cds_lfht_count_nodes(struct cds_lfht *ht,
- long *approx_before,
+ long *split_count_before,
unsigned long *count,
unsigned long *removed,
- long *approx_after);
+ long *split_count_after);
/*
* cds_lfht_lookup - lookup a node by key.
*
* Output in "*iter". *iter->node set to NULL if not found.
* Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
*/
void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len,
struct cds_lfht_iter *iter);
* cds_lfht_next calls, and also between cds_lfht_next calls using the
* node returned by a previous cds_lfht_next.
* Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
*/
void cds_lfht_next_duplicate(struct cds_lfht *ht, struct cds_lfht_iter *iter);
*
* Output in "*iter". *iter->node set to NULL if table is empty.
* Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
*/
void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter);
* Input/Output in "*iter". *iter->node set to NULL if *iter was
* pointing to the last table node.
* Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
*/
void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter);
/*
* cds_lfht_add - add a node to the hash table.
*
- * Call with rcu_read_lock held.
* This function supports adding redundant keys into the table.
+ * Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
*/
void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node);
* cds_lfht_add_unique fails, the node passed as parameter should be
* freed by the caller.
* Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
*
* The semantic of this function is that if only this function is used
* to add keys into the table, no duplicated keys should ever be
* was present, return NULL, which also means the operation succeeded.
* This replacement operation should never fail.
* Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
* After successful replacement, a grace period must be waited for before
* freeing the memory reserved for the returned node.
*
* Old node can be looked up with cds_lfht_lookup and cds_lfht_next.
* RCU read-side lock must be held between lookup and replacement.
* Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
* After successful replacement, a grace period must be waited for before
* freeing the memory reserved for the old node (which can be accessed
* with cds_lfht_iter_get_node).
* cds_lfht_iter_get_node.
* RCU read-side lock must be held between lookup and removal.
* Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
* After successful removal, a grace period must be waited for before
* freeing the memory reserved for old node (which can be accessed with
* cds_lfht_iter_get_node).
/*
* cds_lfht_resize - Force a hash table resize
* @new_size: update to this hash table size.
+ *
+ * Threads calling this API need to be registered RCU read-side threads.
*/
void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size);
projects / lttng-tools.git / blobdiff