X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=rculfhash.c;h=be995dfeaf5ef70795a6fd74a7bc34f4ced558c6;hb=3fb86f26cfea354e44be1099642fc88436e3edf3;hp=c7b9ea895cf6594d11a9ef8a56a461ba3bc2ae7d;hpb=f4a9cc0b4bc9791e18c66b00023ae4ef76befb74;p=urcu.git

diff --git a/rculfhash.c b/rculfhash.c
index c7b9ea8..be995df 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -724,7 +724,12 @@ struct _cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
 
 	assert(size > 0);
 	index = hash & (size - 1);
-	order = get_count_order_ulong(index + 1);
+	/*
+	 * equivalent to get_count_order_ulong(index + 1), but optimizes
+	 * away the non-existing 0 special-case for
+	 * get_count_order_ulong.
+	 */
+	order = fls_ulong(index);
 
 	dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n",
 		   hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1)));
@@ -782,10 +787,10 @@ void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node
 static
 int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
 		struct cds_lfht_node *old_node,
-		struct cds_lfht_node *ret_next,
+		struct cds_lfht_node *old_next,
 		struct cds_lfht_node *new_node)
 {
-	struct cds_lfht_node *dummy, *old_next;
+	struct cds_lfht_node *dummy, *ret_next;
 	struct _cds_lfht_node *lookup;
 	int flagged = 0;
 
@@ -797,9 +802,8 @@ int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
 	assert(!is_removed(new_node));
 	assert(!is_dummy(new_node));
 	assert(new_node != old_node);
-	do {
+	for (;;) {
 		/* Insert after node to be replaced */
-		old_next = ret_next;
 		if (is_removed(old_next)) {
 			/*
 			 * Too late, the old node has been removed under us
@@ -822,7 +826,10 @@ int _cds_lfht_replace(struct cds_lfht *ht, unsigned long size,
 		 */
 		ret_next = uatomic_cmpxchg(&old_node->p.next,
 			      old_next, flag_removed(new_node));
-	} while (ret_next != old_next);
+		if (ret_next == old_next)
+			break;
+		old_next = ret_next;
+	}
 
 	/* We performed the replacement. */
 	flagged = 1;
@@ -855,7 +862,7 @@ struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
 				enum add_mode mode, int dummy)
 {
 	struct cds_lfht_node *iter_prev, *iter, *next, *new_node, *new_next,
-			*dummy_node, *return_node;
+			*return_node;
 	struct _cds_lfht_node *lookup;
 
 	assert(!is_dummy(node));
@@ -882,11 +889,15 @@ struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
 				goto insert;
 			if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash))
 				goto insert;
+			/* dummy node is the first node of the identical-hash-value chain */
+			if (dummy && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash)
+				goto insert;
 			next = rcu_dereference(clear_flag(iter)->p.next);
 			if (unlikely(is_removed(next)))
 				goto gc_node;
 			if ((mode == ADD_UNIQUE || mode == ADD_REPLACE)
 			    && !is_dummy(next)
+			    && clear_flag(iter)->p.reverse_hash == node->p.reverse_hash
 			    && !ht->compare_fct(node->key, node->key_len,
 						clear_flag(iter)->key,
 						clear_flag(iter)->key_len)) {
@@ -924,7 +935,7 @@ struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
 				return_node = NULL;
 			else	/* ADD_DEFAULT and ADD_UNIQUE */
 				return_node = node;
-			goto gc_end;
+			goto end;
 		}
 
 	replace:
@@ -946,10 +957,6 @@ struct cds_lfht_node *_cds_lfht_add(struct cds_lfht *ht,
 		(void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next);
 		/* retry */
 	}
-gc_end:
-	/* Garbage collect logically removed nodes in the bucket */
-	dummy_node = (struct cds_lfht_node *) lookup;
-	_cds_lfht_gc_bucket(dummy_node, node);
 end:
 	return return_node;
 }
@@ -1340,6 +1347,7 @@ void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len,
 		next = rcu_dereference(node->p.next);
 		if (likely(!is_removed(next))
 		    && !is_dummy(next)
+		    && clear_flag(node)->p.reverse_hash == reverse_hash
 		    && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
 				break;
 		}