X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;ds=sidebyside;f=rculfhash.c;h=a3223f37f046021cb6c3c0119e107e2e4dde4fd0;hb=848d408839fe4f829db477644c776eba166a0e9a;hp=0d8c5d6150ae9fa9eecc05d46b96e2ff4e6ef44c;hpb=9dba85be054385dbb40d02631baffdcb735114a4;p=urcu.git

diff --git a/rculfhash.c b/rculfhash.c
index 0d8c5d6..a3223f3 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -67,6 +67,7 @@ struct rcu_ht {
 	ht_compare_fct compare_fct;
 	unsigned long hash_seed;
 	pthread_mutex_t resize_mutex;	/* resize mutex: add/del mutex */
+	unsigned int in_progress_resize;
 	void (*ht_call_rcu)(struct rcu_head *head,
 		      void (*func)(struct rcu_head *head));
 };
@@ -234,13 +235,17 @@ void _ht_gc_bucket(struct rcu_ht_node *dummy, struct rcu_ht_node *node)
 }
 
 static
-int _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node,
-	     int unique)
+struct rcu_ht_node *_ht_add(struct rcu_ht *ht, struct rcu_table *t,
+			    struct rcu_ht_node *node, int unique)
 {
 	struct rcu_ht_node *iter_prev, *dummy, *iter, *next;
+	unsigned long hash;
 
-	if (!t->size)
-		return 0;
+	if (!t->size) {
+		assert(node->dummy);
+		return node;	/* Initial first add (head) */
+	}
+	hash = bit_reverse_ulong(node->reverse_hash);
 	for (;;) {
 		uint32_t chain_len = 0;
 
@@ -248,7 +253,7 @@ int _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node,
 		 * iter_prev points to the non-removed node prior to the
 		 * insert location.
 		 */
-		iter_prev = rcu_dereference(t->tbl[node->hash & (t->size - 1)]);
+		iter_prev = rcu_dereference(t->tbl[hash & (t->size - 1)]);
 		/* We can always skip the dummy node initially */
 		iter = rcu_dereference(iter_prev->next);
 		assert(iter_prev->reverse_hash <= node->reverse_hash);
@@ -260,6 +265,12 @@ int _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node,
 			next = rcu_dereference(clear_flag(iter)->next);
 			if (is_removed(next))
 				goto gc_node;
+			if (unique
+			    && !clear_flag(iter)->dummy
+			    && !ht->compare_fct(node->key, node->key_len,
+						clear_flag(iter)->key,
+						clear_flag(iter)->key_len))
+				return clear_flag(iter);
 			/* Only account for identical reverse hash once */
 			if (iter_prev->reverse_hash != clear_flag(iter)->reverse_hash)
 				check_resize(ht, t, ++chain_len);
@@ -283,9 +294,9 @@ int _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node,
 	}
 gc_end:
 	/* Garbage collect logically removed nodes in the bucket */
-	dummy = rcu_dereference(t->tbl[node->hash & (t->size - 1)]);
+	dummy = rcu_dereference(t->tbl[hash & (t->size - 1)]);
 	_ht_gc_bucket(dummy, node);
-	return 0;
+	return node;
 }
 
 static
@@ -293,6 +304,7 @@ int _ht_remove(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node)
 {
 	struct rcu_ht_node *dummy, *next, *old;
 	int flagged = 0;
+	unsigned long hash;
 
 	/* logically delete the node */
 	old = rcu_dereference(node->next);
@@ -313,7 +325,8 @@ int _ht_remove(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node)
 	 * the node, and remove it (along with any other logically removed node)
 	 * if found.
 	 */
-	dummy = rcu_dereference(t->tbl[node->hash & (t->size - 1)]);
+	hash = bit_reverse_ulong(node->reverse_hash);
+	dummy = rcu_dereference(t->tbl[hash & (t->size - 1)]);
 	_ht_gc_bucket(dummy, node);
 end:
 	/*
@@ -340,7 +353,6 @@ void init_table(struct rcu_ht *ht, struct rcu_table *t,
 			t->size = i;
 		t->tbl[i] = calloc(1, sizeof(struct rcu_ht_node));
 		t->tbl[i]->dummy = 1;
-		t->tbl[i]->hash = i;
 		t->tbl[i]->reverse_hash = bit_reverse_ulong(i);
 		(void) _ht_add(ht, t, t->tbl[i], 0);
 	}
@@ -362,6 +374,7 @@ struct rcu_ht *ht_new(ht_hash_fct hash_fct,
 	ht->compare_fct = compare_fct;
 	ht->hash_seed = hash_seed;
 	ht->ht_call_rcu = ht_call_rcu;
+	ht->in_progress_resize = 0;
 	/* this mutex should not nest in read-side C.S. */
 	pthread_mutex_init(&ht->resize_mutex, NULL);
 	ht->t = calloc(1, sizeof(struct rcu_table)
@@ -391,9 +404,9 @@ struct rcu_ht_node *ht_lookup(struct rcu_ht *ht, void *key, size_t key_len)
 			node = NULL;
 			break;
 		}
-		if (!ht->compare_fct(node->key, node->key_len, key, key_len)) {
-			if (likely(!is_removed(rcu_dereference(node->next)))
-			    && likely(!node->dummy))
+		if (likely(!is_removed(rcu_dereference(node->next)))
+		    && !node->dummy
+		    && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
 				break;
 		}
 		node = clear_flag(rcu_dereference(node->next));
@@ -405,20 +418,22 @@ struct rcu_ht_node *ht_lookup(struct rcu_ht *ht, void *key, size_t key_len)
 void ht_add(struct rcu_ht *ht, struct rcu_ht_node *node)
 {
 	struct rcu_table *t;
+	unsigned long hash;
 
-	node->hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
-	node->reverse_hash = bit_reverse_ulong((unsigned long) node->hash);
+	hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
+	node->reverse_hash = bit_reverse_ulong((unsigned long) hash);
 
 	t = rcu_dereference(ht->t);
 	(void) _ht_add(ht, t, node, 0);
 }
 
-int ht_add_unique(struct rcu_ht *ht, struct rcu_ht_node *node)
+struct rcu_ht_node *ht_add_unique(struct rcu_ht *ht, struct rcu_ht_node *node)
 {
 	struct rcu_table *t;
+	unsigned long hash;
 
-	node->hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
-	node->reverse_hash = bit_reverse_ulong((unsigned long) node->hash);
+	hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
+	node->reverse_hash = bit_reverse_ulong((unsigned long) hash);
 
 	t = rcu_dereference(ht->t);
 	return _ht_add(ht, t, node, 1);
@@ -464,6 +479,9 @@ int ht_destroy(struct rcu_ht *ht)
 {
 	int ret;
 
+	/* Wait for in-flight resize operations to complete */
+	while (uatomic_read(&ht->in_progress_resize))
+		poll(NULL, 0, 100);	/* wait for 100ms */
 	ret = ht_delete_dummy(ht);
 	if (ret)
 		return ret;
@@ -563,6 +581,8 @@ void do_resize_cb(struct rcu_head *head)
 	_do_ht_resize(ht);
 	pthread_mutex_unlock(&ht->resize_mutex);
 	free(work);
+	cmm_smp_mb();	/* finish resize before decrement */
+	uatomic_dec(&ht->in_progress_resize);
 }
 
 static
@@ -573,6 +593,8 @@ void ht_resize_lazy(struct rcu_ht *ht, struct rcu_table *t, int growth)
 
 	target_size = resize_target_update(t, growth);
 	if (!CMM_LOAD_SHARED(t->resize_initiated) && t->size < target_size) {
+		uatomic_inc(&ht->in_progress_resize);
+		cmm_smp_mb();	/* increment resize count before calling it */
 		work = malloc(sizeof(*work));
 		work->ht = ht;
 		ht->ht_call_rcu(&work->head, do_resize_cb);