return v;
}
+static
+struct _cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
+ unsigned long hash)
+{
+ unsigned long index, order;
+
+ assert(size > 0);
+ index = hash & (size - 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)));
+
+ return &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))];
+}
+
/*
* Remove all logically deleted nodes from a bucket up to a certain node key.
*/
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;
- unsigned long hash, index, order;
if (!old_node) /* Return -ENOENT if asked to replace NULL node */
goto end;
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
*/
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;
* lookup for the node, and remove it (along with any other
* logically removed node) if found.
*/
- hash = bit_reverse_ulong(old_node->p.reverse_hash);
- assert(size > 0);
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))];
+ lookup = lookup_bucket(ht, size, bit_reverse_ulong(old_node->p.reverse_hash));
dummy = (struct cds_lfht_node *) lookup;
_cds_lfht_gc_bucket(dummy, new_node);
end:
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;
- unsigned long hash, index, order;
assert(!is_dummy(node));
assert(!is_removed(node));
node->p.next = flag_dummy(get_end());
return node; /* Initial first add (head) */
}
- hash = bit_reverse_ulong(node->p.reverse_hash);
+ lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash));
for (;;) {
uint32_t chain_len = 0;
* iter_prev points to the non-removed node prior to the
* insert location.
*/
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & ((!order ? 0 : (1UL << (order - 1))) - 1)];
iter_prev = (struct cds_lfht_node *) lookup;
/* We can always skip the dummy node initially */
iter = rcu_dereference(iter_prev->p.next);
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)) {
return_node = NULL;
else /* ADD_DEFAULT and ADD_UNIQUE */
return_node = node;
- goto gc_end;
+ goto end;
}
replace:
(void) uatomic_cmpxchg(&iter_prev->p.next, iter, new_next);
/* retry */
}
-gc_end:
- /* Garbage collect logically removed nodes in the bucket */
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))];
- dummy_node = (struct cds_lfht_node *) lookup;
- _cds_lfht_gc_bucket(dummy_node, node);
end:
return return_node;
}
struct cds_lfht_node *dummy, *next, *old;
struct _cds_lfht_node *lookup;
int flagged = 0;
- unsigned long hash, index, order;
if (!node) /* Return -ENOENT if asked to delete NULL node */
goto end;
* the node, and remove it (along with any other logically removed node)
* if found.
*/
- hash = bit_reverse_ulong(node->p.reverse_hash);
- assert(size > 0);
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))];
+ lookup = lookup_bucket(ht, size, bit_reverse_ulong(node->p.reverse_hash));
dummy = (struct cds_lfht_node *) lookup;
_cds_lfht_gc_bucket(dummy, node);
end:
{
struct cds_lfht_node *node, *next, *dummy_node;
struct _cds_lfht_node *lookup;
- unsigned long hash, reverse_hash, index, order, size;
+ unsigned long hash, reverse_hash, size;
hash = ht->hash_fct(key, key_len, ht->hash_seed);
reverse_hash = bit_reverse_ulong(hash);
size = rcu_dereference(ht->t.size);
- index = hash & (size - 1);
- order = get_count_order_ulong(index + 1);
- lookup = &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1))) - 1)];
- dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n",
- hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1)));
+ lookup = lookup_bucket(ht, size, hash);
dummy_node = (struct cds_lfht_node *) lookup;
/* We can always skip the dummy node initially */
node = rcu_dereference(dummy_node->p.next);
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;
}
projects / urcu.git / blobdiff