#define JA_ENTRY_PER_NODE 256UL
#define JA_BITS_PER_BYTE 3
+#define JA_MAX_INTERNAL_DEPTH 5 /* Maximum depth, excluding leafs */
+
/*
* Entry for NULL node is at index 8 of the table. It is never encoded
* in flags.
static
struct cds_ja_inode_flag *ja_linear_node_get_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
+ struct cds_ja_inode_flag ***child_node_flag_ptr,
uint8_t n)
{
uint8_t nr_child;
if (i >= nr_child)
return NULL;
pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]);
+ if (caa_unlikely(child_node_flag_ptr))
+ *child_node_flag_ptr = &pointers[i];
ptr = rcu_dereference(pointers[i]);
assert(ja_node_ptr(ptr) != NULL);
return ptr;
}
static
-struct cds_ja_inode_flag *ja_linear_node_get_ith_pos(const struct cds_ja_type *type,
+void ja_linear_node_get_ith_pos(const struct cds_ja_type *type,
struct cds_ja_inode *node,
uint8_t i,
uint8_t *v,
static
struct cds_ja_inode_flag *ja_pool_node_get_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
+ struct cds_ja_inode_flag ***child_node_flag_ptr,
uint8_t n)
{
struct cds_ja_inode *linear;
*/
linear = (struct cds_ja_inode *)
&node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
- return ja_linear_node_get_nth(type, linear, n);
+ return ja_linear_node_get_nth(type, linear, child_node_flag_ptr, n);
}
static
static
struct cds_ja_inode_flag *ja_pigeon_node_get_nth(const struct cds_ja_type *type,
struct cds_ja_inode *node,
+ struct cds_ja_inode_flag ***child_node_flag_ptr,
uint8_t n)
{
+ struct cds_ja_inode_flag **child_node_flag;
+
assert(type->type_class == RCU_JA_PIGEON);
- return rcu_dereference(((struct cds_ja_inode_flag **) node->u.data)[n]);
+ child_node_flag = &((struct cds_ja_inode_flag **) node->u.data)[n];
+ if (caa_unlikely(child_node_flag_ptr))
+ *child_node_flag_ptr = child_node_flag;
+ return rcu_dereference(*child_node_flag);
}
/*
*/
static
struct cds_ja_inode_flag * ja_node_get_nth(struct cds_ja_inode_flag *node_flag,
+ struct cds_ja_inode_flag ***child_node_flag_ptr,
uint8_t n)
{
unsigned int type_index;
const struct cds_ja_type *type;
node = ja_node_ptr(node_flag);
- if (caa_unlikely(node == NULL))
- return NULL;
+ assert(node != NULL);
type_index = ja_node_type(node_flag);
type = &ja_types[type_index];
switch (type->type_class) {
case RCU_JA_LINEAR:
- return ja_linear_node_get_nth(type, node, n);
+ return ja_linear_node_get_nth(type, node,
+ child_node_flag_ptr, n);
case RCU_JA_POOL:
- return ja_pool_node_get_nth(type, node, n);
+ return ja_pool_node_get_nth(type, node,
+ child_node_flag_ptr, n);
case RCU_JA_PIGEON:
- return ja_pigeon_node_get_nth(type, node, n);
+ return ja_pigeon_node_get_nth(type, node,
+ child_node_flag_ptr, n);
default:
assert(0);
return (void *) -1UL;
assert(type->type_class == RCU_JA_PIGEON);
ptr = &((struct cds_ja_inode_flag **) node->u.data)[n];
- if (*ptr != NULL)
+ if (*ptr)
return -EEXIST;
rcu_assign_pointer(*ptr, child_node_flag);
shadow_node->nr_child++;
/*
* ja_node_recompact_add: recompact a node, adding a new child.
* TODO: for pool type, take selection bit(s) into account.
+ * Return 0 on success, -ENOENT if need to retry, or other negative
+ * error value otherwise.
*/
static
int ja_node_recompact_add(struct cds_ja *ja,
unsigned int old_type_index,
const struct cds_ja_type *old_type,
struct cds_ja_inode *old_node,
- struct cds_ja_shadow_node **shadow_node,
+ struct cds_ja_shadow_node *shadow_node,
struct cds_ja_inode_flag **old_node_flag, uint8_t n,
struct cds_ja_inode_flag *child_node_flag)
{
struct cds_ja_inode *new_node;
const struct cds_ja_type *new_type;
struct cds_ja_inode_flag *new_node_flag;
+ int new_shadow = 0;
int ret;
- if (*shadow_node == NULL) {
+ if (!shadow_node) {
new_type_index = 0;
} else {
new_type_index = old_type_index + 1;
return -ENOMEM;
new_node_flag = ja_node_flag(new_node, new_type_index);
- ret = rcuja_shadow_set(ja->ht, new_node, *shadow_node);
- if (ret)
+ ret = rcuja_shadow_set(ja->ht, new_node, shadow_node);
+ if (ret) {
+ free(new_node);
return ret;
+ }
- if (*shadow_node == NULL) {
- *shadow_node = rcuja_shadow_lookup_lock(ja->ht, new_node);
- assert(*shadow_node);
+ if (!shadow_node) {
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht, new_node);
+ assert(shadow_node);
+ new_shadow = 1;
}
/*
* We need to clear nr_child, because it will be re-incremented
* by _ja_node_set_nth().
*/
- (*shadow_node)->nr_child = 0;
+ shadow_node->nr_child = 0;
assert(old_type->type_class != RCU_JA_PIGEON);
switch (old_type->type_class) {
ja_linear_node_get_ith_pos(old_type, old_node, i, &v, &iter);
if (!iter)
continue;
- ret = _ja_node_set_nth(new_type, new_node, *shadow_node,
+ ret = _ja_node_set_nth(new_type, new_node, shadow_node,
v, iter);
assert(!ret);
}
j, &v, &iter);
if (!iter)
continue;
- ret = _ja_node_set_nth(new_type, new_node, *shadow_node,
+ ret = _ja_node_set_nth(new_type, new_node, shadow_node,
v, iter);
assert(!ret);
}
case RCU_JA_PIGEON:
default:
assert(0);
- return -EINVAL;
+ ret = -EINVAL;
+ goto unlock_new_shadow;
}
/* add node */
- ret = _ja_node_set_nth(new_type, new_node, *shadow_node,
+ ret = _ja_node_set_nth(new_type, new_node, shadow_node,
n, child_node_flag);
assert(!ret);
- /* Replace the old node with the new recompacted one */
- rcu_assign_pointer(*old_node_flag, new_node_flag);
+ /* Return pointer to new recompacted new through old_node_flag */
+ *old_node_flag = new_node_flag;
ret = rcuja_shadow_clear(ja->ht, old_node,
RCUJA_SHADOW_CLEAR_FREE_NODE);
assert(!ret);
- return 0;
+
+ ret = 0;
+
+unlock_new_shadow:
+ if (new_shadow)
+ rcuja_shadow_unlock(shadow_node);
+ return ret;
}
+/*
+ * Return 0 on success, -ENOENT if need to retry, or other negative
+ * error value otherwise.
+ */
static
int ja_node_set_nth(struct cds_ja *ja,
struct cds_ja_inode_flag **node_flag, uint8_t n,
- struct cds_ja_inode_flag *child_node_flag)
+ struct cds_ja_inode_flag *child_node_flag,
+ struct cds_ja_shadow_node *shadow_node)
{
int ret;
unsigned int type_index;
const struct cds_ja_type *type;
struct cds_ja_inode *node;
- struct cds_ja_shadow_node *shadow_node = NULL;
node = ja_node_ptr(*node_flag);
type_index = ja_node_type(*node_flag);
type = &ja_types[type_index];
- if (node != NULL) {
- shadow_node = rcuja_shadow_lookup_lock(ja->ht, node);
- assert(shadow_node);
- }
ret = _ja_node_set_nth(type, node, shadow_node,
n, child_node_flag);
if (ret == -ENOSPC) {
/* Not enough space in node, need to recompact. */
ret = ja_node_recompact_add(ja, type_index, type, node,
- &shadow_node, node_flag, n, child_node_flag);
- /* recompact always leave shadow_node locked */
+ shadow_node, node_flag, n, child_node_flag);
}
- rcuja_shadow_unlock(shadow_node);
return ret;
}
-struct cds_ja_node *cds_ja_lookup(struct cds_ja *ja, uint64_t key)
+struct cds_hlist_head *cds_ja_lookup(struct cds_ja *ja, uint64_t key)
{
unsigned int tree_depth, i;
struct cds_ja_inode_flag *node_flag;
if (caa_unlikely(key > ja->key_max))
return NULL;
tree_depth = ja->tree_depth;
- node_flag = ja->root;
+ node_flag = rcu_dereference(ja->root);
- for (i = 0; i < tree_depth; i++) {
- node_flag = ja_node_get_nth(node_flag,
+ /* level 0: root node */
+ if (!ja_node_ptr(node_flag))
+ return NULL;
+
+ for (i = 1; i < tree_depth; i++) {
+ node_flag = ja_node_get_nth(node_flag, NULL,
(unsigned char) key);
if (!ja_node_ptr(node_flag))
return NULL;
key >>= JA_BITS_PER_BYTE;
}
- /* Last level lookup succeded. We got an actual node. */
- return (struct cds_ja_node *) node_flag;
+ /* Last level lookup succeded. We got an actual match. */
+ return (struct cds_hlist_head *) node_flag;
+}
+
+/*
+ * We reached an unpopulated node. Create it and the children we need,
+ * and then attach the entire branch to the current node. This may
+ * trigger recompaction of the current node. Locks needed: node lock
+ * (for add), and, possibly, parent node lock (to update pointer due to
+ * node recompaction).
+ *
+ * First take node lock, check if recompaction is needed, then take
+ * parent lock (if needed). Then we can proceed to create the new
+ * branch. Publish the new branch, and release locks.
+ * TODO: we currently always take the parent lock even when not needed.
+ */
+static
+int ja_attach_node(struct cds_ja *ja,
+ struct cds_ja_inode_flag **node_flag_ptr,
+ struct cds_ja_inode_flag *node_flag,
+ struct cds_ja_inode_flag *parent_node_flag,
+ uint64_t key,
+ unsigned int depth,
+ struct cds_ja_node *child_node)
+{
+ struct cds_ja_shadow_node *shadow_node = NULL,
+ *parent_shadow_node = NULL;
+ struct cds_ja_inode *node = ja_node_ptr(node_flag);
+ struct cds_ja_inode *parent_node = ja_node_ptr(parent_node_flag);
+ struct cds_hlist_head head;
+ struct cds_ja_inode_flag *iter_node_flag, *iter_dest_node_flag;
+ int ret, i;
+ struct cds_ja_inode_flag *created_nodes[JA_MAX_INTERNAL_DEPTH];
+ int nr_created_nodes = 0;
+
+ assert(node);
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht, node);
+ if (!shadow_node) {
+ ret = -ENOENT;
+ goto end;
+ }
+ if (parent_node) {
+ parent_shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ parent_node);
+ if (!parent_shadow_node) {
+ ret = -ENOENT;
+ goto unlock_shadow;
+ }
+ }
+
+ CDS_INIT_HLIST_HEAD(&head);
+ cds_hlist_add_head_rcu(&child_node->list, &head);
+
+ iter_dest_node_flag = NULL;
+ ret = ja_node_set_nth(ja, &iter_dest_node_flag,
+ key >> (JA_BITS_PER_BYTE * (ja->tree_depth - 2)),
+ (struct cds_ja_inode_flag *) head.next,
+ NULL);
+ if (ret)
+ goto unlock_parent;
+ created_nodes[nr_created_nodes++] = iter_dest_node_flag;
+ iter_node_flag = iter_dest_node_flag;
+
+ /* Create new branch, starting from bottom */
+ for (i = ja->tree_depth - 2; i >= (int) depth; i--) {
+ iter_dest_node_flag = NULL;
+ ret = ja_node_set_nth(ja, &iter_dest_node_flag,
+ key >> (JA_BITS_PER_BYTE * (i - 1)),
+ iter_node_flag,
+ NULL);
+ if (ret)
+ goto check_error;
+ created_nodes[nr_created_nodes++] = iter_dest_node_flag;
+ iter_node_flag = iter_dest_node_flag;
+ }
+
+ /* Publish new branch */
+ rcu_assign_pointer(*node_flag_ptr, iter_node_flag);
+
+ /* Success */
+ ret = 0;
+
+check_error:
+ if (ret) {
+ for (i = 0; i < nr_created_nodes; i++) {
+ int tmpret;
+ tmpret = rcuja_shadow_clear(ja->ht,
+ ja_node_ptr(created_nodes[i]),
+ RCUJA_SHADOW_CLEAR_FREE_NODE
+ | RCUJA_SHADOW_CLEAR_FREE_LOCK);
+ assert(!tmpret);
+ }
+ }
+unlock_parent:
+ if (parent_shadow_node)
+ rcuja_shadow_unlock(parent_shadow_node);
+unlock_shadow:
+ if (shadow_node)
+ rcuja_shadow_unlock(shadow_node);
+end:
+ return ret;
+}
+
+/*
+ * Lock the hlist head shadow node mutex, and add node to list of
+ * duplicates. Failure can happen if concurrent removal removes the last
+ * node with same key before we get the lock.
+ * Return 0 on success, negative error value on failure.
+ */
+static
+int ja_chain_node(struct cds_ja *ja,
+ struct cds_hlist_head *head,
+ struct cds_ja_node *node)
+{
+ struct cds_ja_shadow_node *shadow_node;
+
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ (struct cds_ja_inode *) head);
+ if (!shadow_node)
+ return -ENOENT;
+ cds_hlist_add_head_rcu(&node->list, head);
+ rcuja_shadow_unlock(shadow_node);
+ return 0;
+}
+
+int cds_ja_add(struct cds_ja *ja, uint64_t key,
+ struct cds_ja_node *new_node)
+{
+ unsigned int tree_depth, i;
+ uint64_t iter_key;
+ struct cds_ja_inode_flag **node_flag_ptr; /* in parent */
+ struct cds_ja_inode_flag *node_flag,
+ *parent_node_flag,
+ *parent2_node_flag;
+ int ret;
+
+ if (caa_unlikely(key > ja->key_max))
+ return -EINVAL;
+ tree_depth = ja->tree_depth;
+
+retry:
+ iter_key = key;
+ parent2_node_flag = NULL;
+ parent_node_flag = NULL;
+ node_flag_ptr = &ja->root;
+ node_flag = rcu_dereference(*node_flag_ptr);
+
+ /* Iterate on all internal levels */
+ for (i = 0; i < tree_depth - 1; i++) {
+ if (!ja_node_ptr(node_flag)) {
+ ret = ja_attach_node(ja, node_flag_ptr,
+ parent_node_flag, parent2_node_flag,
+ key, i, new_node);
+ if (ret == -ENOENT || ret == -EEXIST)
+ goto retry;
+ else
+ goto end;
+ }
+ parent2_node_flag = parent_node_flag;
+ parent_node_flag = node_flag;
+ node_flag = ja_node_get_nth(node_flag,
+ &node_flag_ptr,
+ (unsigned char) iter_key);
+ iter_key >>= JA_BITS_PER_BYTE;
+ }
+
+ /*
+ * We reached bottom of tree, simply add node to last internal
+ * level, or chain it if key is already present.
+ */
+ if (!ja_node_ptr(node_flag)) {
+ ret = ja_attach_node(ja, node_flag_ptr, parent_node_flag,
+ parent2_node_flag, key, i, new_node);
+ } else {
+ ret = ja_chain_node(ja,
+ (struct cds_hlist_head *) ja_node_ptr(node_flag),
+ new_node);
+ }
+ if (ret == -ENOENT)
+ goto retry;
+end:
+ return ret;
}
struct cds_ja *_cds_ja_new(unsigned int key_bits,
{
struct cds_ja *ja;
-
ja = calloc(sizeof(*ja), 1);
if (!ja)
goto ja_error;
}
/* ja->root is NULL */
- ja->tree_depth = key_bits >> JA_BITS_PER_BYTE;
+ /* tree_depth 0 is for pointer to root node */
+ ja->tree_depth = (key_bits >> JA_BITS_PER_BYTE) + 1;
+ assert(ja->tree_depth <= JA_MAX_INTERNAL_DEPTH + 1);
ja->ht = rcuja_create_ht(flavor);
if (!ja->ht)
goto ht_error;
projects / userspace-rcu.git / commitdiff
