X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Frculfhash.h;h=4f7cc526f9ddc93528276c3e5740dab9c6f54f9f;hp=46c0beaf03a5e71fe74dd41c00f9e48fbd8dc32e;hb=6083a889a5782bfa6dd28594f56062eea8d04dc8;hpb=14044b37bb7ba51676f1c3f139facae9b06dbc51

diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index 46c0bea..4f7cc52 100644
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -21,6 +21,8 @@
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Include this file _after_ including your URCU flavor.
  */
 
 #include <stdint.h>
@@ -72,22 +74,80 @@ void cds_lfht_node_init(struct cds_lfht_node *node, void *key,
 	node->key_len = key_len;
 }
 
+/*
+ * Hash table creation flags.
+ */
+enum {
+	CDS_LFHT_AUTO_RESIZE = (1U << 0),
+};
+
+/*
+ * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly.
+ */
+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,
+			int flags,
+			void (*cds_lfht_call_rcu)(struct rcu_head *head,
+				void (*func)(struct rcu_head *head)),
+			void (*cds_lfht_synchronize_rcu)(void),
+			void (*cds_lfht_rcu_read_lock)(void),
+			void (*cds_lfht_rcu_read_unlock)(void),
+			void (*cds_lfht_rcu_thread_offline)(void),
+			void (*cds_lfht_rcu_thread_online)(void),
+			void (*cds_lfht_rcu_register_thread)(void),
+			void (*cds_lfht_rcu_unregister_thread)(void),
+			pthread_attr_t *attr);
+
 /*
  * cds_lfht_new - allocate a hash table.
+ * @hash_fct: the hashing function.
+ * @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.
+ * @flags: hash table creation flags (can be combined with bitwise or: '|').
+ *           0: no flags.
+ *           CDS_LFHT_AUTO_RESIZE: automatically resize hash table.
+ * @attr: optional resize worker thread attributes. NULL for default.
+ *
+ * Return NULL on error.
+ * Note: the RCU flavor must be already included before the hash table header.
  *
- * init_size must be power of two.
+ * The programmer is responsible for ensuring that resize operation has a
+ * priority equal to hash table updater threads. It should be performed by
+ * specifying the appropriate priority in the pthread "attr" argument, and,
+ * for CDS_LFHT_AUTO_RESIZE, by ensuring that call_rcu worker threads also have
+ * 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.
  */
+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,
-			void (*cds_lfht_call_rcu)(struct rcu_head *head,
-				void (*func)(struct rcu_head *head)));
+			int flags,
+			pthread_attr_t *attr)
+{
+	return _cds_lfht_new(hash_fct, compare_fct, hash_seed,
+			init_size, flags,
+			call_rcu, synchronize_rcu, rcu_read_lock,
+			rcu_read_unlock, rcu_thread_offline,
+			rcu_thread_online, rcu_register_thread,
+			rcu_unregister_thread, attr);
+}
 
 /*
  * cds_lfht_destroy - destroy a hash table.
+ * @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.
+ *
+ * Return 0 on success, negative error value on error.
  */
-int cds_lfht_destroy(struct cds_lfht *ht);
+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.
@@ -101,7 +161,7 @@ void cds_lfht_count_nodes(struct cds_lfht *ht,
 /*
  * cds_lfht_lookup - lookup a node by key.
  *
- * Returns NULL if not found.
+ * Return NULL if not found.
  * Call with rcu_read_lock held.
  */
 struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len);
@@ -109,7 +169,7 @@ struct cds_lfht_node *cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key
 /*
  * cds_lfht_next - get the next item with same key (after a lookup).
  *
- * Returns NULL if no following node exists with same key.
+ * Return NULL if no following node exists with same key.
  * RCU read-side lock must be held across cds_lfht_lookup and 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.
@@ -126,8 +186,8 @@ void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node);
 /*
  * cds_lfht_add_unique - add a node to hash table, if key is not present.
  *
- * Returns the node added upon success.
- * Returns the unique node already present upon failure. If cds_lfht_add_unique fails,
+ * Return the node added upon success.
+ * Return the unique node already present upon failure. If cds_lfht_add_unique fails,
  * the node passed as parameter should be freed by the caller.
  * Call with rcu_read_lock held.
  */
@@ -144,11 +204,9 @@ int cds_lfht_remove(struct cds_lfht *ht, struct cds_lfht_node *node);
 
 /*
  * cds_lfht_resize - Force a hash table resize
- * @growth: growth order (current size is multiplied by 2^growth)
- *
- * Currently, only expand operation is supported (growth >= 0).
+ * @new_size: update to this hash table size.
  */
-void cds_lfht_resize(struct cds_lfht *ht, int growth);
+void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size);
 
 #ifdef __cplusplus
 }