}
static
-int ja_linear_node_clear_nth(const struct cds_ja_type *type,
+int ja_linear_node_clear_ptr(const struct cds_ja_type *type,
struct cds_ja_inode *node,
struct cds_ja_shadow_node *shadow_node,
- uint8_t n)
+ struct cds_ja_inode_flag **node_flag_ptr)
{
uint8_t nr_child;
- uint8_t *values, *nr_child_ptr;
- struct cds_ja_inode_flag **pointers;
- unsigned int i;
+ uint8_t *nr_child_ptr;
assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL);
nr_child_ptr = &node->u.data[0];
- dbg_printf("linear clear nth: nr_child_ptr %p\n", nr_child_ptr);
+ dbg_printf("linear clear ptr: nr_child_ptr %p\n", nr_child_ptr);
nr_child = *nr_child_ptr;
assert(nr_child <= type->max_linear_child);
- values = &node->u.data[1];
- pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]);
- for (i = 0; i < nr_child; i++) {
- if (values[i] == n) {
- if (pointers[i])
- break;
- else
- return -ENOENT;
- }
- }
- if (i >= nr_child)
- return -ENOENT;
if (shadow_node->fallback_removal_count) {
shadow_node->fallback_removal_count--;
} else {
return -EFBIG;
}
}
- assert(pointers[i] != NULL);
- rcu_assign_pointer(pointers[i], NULL);
+ assert(*node_flag_ptr != NULL);
+ rcu_assign_pointer(*node_flag_ptr, NULL);
/*
* Value and nr_child are never changed (would cause ABA issue).
* Instead, we leave the pointer to NULL and recompact the node
* Only update the shadow node accounting.
*/
shadow_node->nr_child--;
- dbg_printf("linear set nth: %u child, shadow: %u child, for node %p shadow %p\n",
+ dbg_printf("linear clear ptr: %u child, shadow: %u child, for node %p shadow %p\n",
(unsigned int) CMM_LOAD_SHARED(*nr_child_ptr),
(unsigned int) shadow_node->nr_child,
node, shadow_node);
}
static
-int ja_pool_node_clear_nth(const struct cds_ja_type *type,
+int ja_pool_node_clear_ptr(const struct cds_ja_type *type,
struct cds_ja_inode *node,
struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr,
uint8_t n)
{
struct cds_ja_inode *linear;
assert(type->type_class == RCU_JA_POOL);
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_clear_nth(type, linear, shadow_node, n);
+ return ja_linear_node_clear_ptr(type, linear, shadow_node, node_flag_ptr);
}
static
-int ja_pigeon_node_clear_nth(const struct cds_ja_type *type,
+int ja_pigeon_node_clear_ptr(const struct cds_ja_type *type,
struct cds_ja_inode *node,
struct cds_ja_shadow_node *shadow_node,
- uint8_t n)
+ struct cds_ja_inode_flag **node_flag_ptr)
{
- struct cds_ja_inode_flag **ptr;
-
assert(type->type_class == RCU_JA_PIGEON);
- ptr = &((struct cds_ja_inode_flag **) node->u.data)[n];
- if (!*ptr)
- return -ENOENT;
- rcu_assign_pointer(*ptr, NULL);
+ rcu_assign_pointer(*node_flag_ptr, NULL);
shadow_node->nr_child--;
return 0;
}
/*
- * _ja_node_clear_nth: clear nth item within a node. Return an error
+ * _ja_node_clear_ptr: clear ptr item within a node. Return an error
* (negative error value) if it is not found (-ENOENT).
*/
static
-int _ja_node_clear_nth(const struct cds_ja_type *type,
+int _ja_node_clear_ptr(const struct cds_ja_type *type,
struct cds_ja_inode *node,
struct cds_ja_shadow_node *shadow_node,
+ struct cds_ja_inode_flag **node_flag_ptr,
uint8_t n)
{
switch (type->type_class) {
case RCU_JA_LINEAR:
- return ja_linear_node_clear_nth(type, node, shadow_node, n);
+ return ja_linear_node_clear_ptr(type, node, shadow_node, node_flag_ptr);
case RCU_JA_POOL:
- return ja_pool_node_clear_nth(type, node, shadow_node, n);
+ return ja_pool_node_clear_ptr(type, node, shadow_node, node_flag_ptr, n);
case RCU_JA_PIGEON:
- return ja_pigeon_node_clear_nth(type, node, shadow_node, n);
+ return ja_pigeon_node_clear_ptr(type, node, shadow_node, node_flag_ptr);
case RCU_JA_NULL:
return -ENOENT;
default:
struct cds_ja_inode *old_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_flag *child_node_flag,
+ struct cds_ja_inode_flag **nullify_node_flag_ptr)
{
unsigned int new_type_index;
struct cds_ja_inode *new_node;
- struct cds_ja_shadow_node *new_shadow_node;
+ struct cds_ja_shadow_node *new_shadow_node = NULL;
const struct cds_ja_type *new_type;
struct cds_ja_inode_flag *new_node_flag;
int ret;
ja_linear_node_get_ith_pos(old_type, old_node, i, &v, &iter);
if (!iter)
continue;
- if (mode == JA_RECOMPACT_DEL && v == n)
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
continue;
ret = _ja_node_set_nth(new_type, new_node,
new_shadow_node,
j, &v, &iter);
if (!iter)
continue;
- if (mode == JA_RECOMPACT_DEL && v == n)
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
continue;
ret = _ja_node_set_nth(new_type, new_node,
new_shadow_node,
iter = ja_pigeon_node_get_ith_pos(old_type, old_node, i);
if (!iter)
continue;
- if (mode == JA_RECOMPACT_DEL && i == n)
+ if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter)
continue;
ret = _ja_node_set_nth(new_type, new_node,
new_shadow_node,
fallback_toosmall:
/* fallback if next pool is too small */
+ assert(new_shadow_node);
ret = rcuja_shadow_clear(ja->ht, new_node, new_shadow_node,
RCUJA_SHADOW_CLEAR_FREE_NODE);
assert(!ret);
case -ENOSPC:
/* Not enough space in node, need to recompact. */
ret = ja_node_recompact(JA_RECOMPACT_ADD, ja, type_index, type, node,
- shadow_node, node_flag, n, child_node_flag);
+ shadow_node, node_flag, n, child_node_flag, NULL);
break;
case -ERANGE:
/* Node needs to be recompacted. */
ret = ja_node_recompact(JA_RECOMPACT, ja, type_index, type, node,
- shadow_node, node_flag, n, child_node_flag);
+ shadow_node, node_flag, n, child_node_flag, NULL);
break;
}
return ret;
* error value otherwise.
*/
static
-int ja_node_clear_nth(struct cds_ja *ja,
- struct cds_ja_inode_flag **node_flag, uint8_t n,
- struct cds_ja_shadow_node *shadow_node)
+int ja_node_clear_ptr(struct cds_ja *ja,
+ struct cds_ja_inode_flag **node_flag_ptr, /* Pointer to location to nullify */
+ struct cds_ja_inode_flag **parent_node_flag_ptr, /* Address of parent ptr in its parent */
+ struct cds_ja_shadow_node *shadow_node, /* of parent */
+ uint8_t n)
{
int ret;
unsigned int type_index;
const struct cds_ja_type *type;
struct cds_ja_inode *node;
- dbg_printf("ja_node_clear_nth for n=%u, node %p, shadow %p\n",
- (unsigned int) n, ja_node_ptr(*node_flag), shadow_node);
+ dbg_printf("ja_node_clear_ptr for node %p, shadow %p, target ptr %p\n",
+ ja_node_ptr(*parent_node_flag_ptr), shadow_node, node_flag_ptr);
- node = ja_node_ptr(*node_flag);
- type_index = ja_node_type(*node_flag);
+ node = ja_node_ptr(*parent_node_flag_ptr);
+ type_index = ja_node_type(*parent_node_flag_ptr);
type = &ja_types[type_index];
- ret = _ja_node_clear_nth(type, node, shadow_node, n);
+ ret = _ja_node_clear_ptr(type, node, shadow_node, node_flag_ptr, n);
if (ret == -EFBIG) {
/* Should to try recompaction. */
ret = ja_node_recompact(JA_RECOMPACT_DEL, ja, type_index, type, node,
- shadow_node, node_flag, n, NULL);
+ shadow_node, parent_node_flag_ptr, n, NULL,
+ node_flag_ptr);
}
return ret;
}
-struct cds_hlist_head *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;
+ struct cds_hlist_head head = { NULL };
if (caa_unlikely(key > ja->key_max))
- return NULL;
+ return head;
tree_depth = ja->tree_depth;
node_flag = rcu_dereference(ja->root);
/* level 0: root node */
if (!ja_node_ptr(node_flag))
- return NULL;
+ return head;
for (i = 1; i < tree_depth; i++) {
uint8_t iter_key;
dbg_printf("cds_ja_lookup iter key lookup %u finds node_flag %p\n",
(unsigned int) iter_key, node_flag);
if (!ja_node_ptr(node_flag))
- return NULL;
+ return head;
}
/* Last level lookup succeded. We got an actual match. */
- return (struct cds_hlist_head *) node_flag;
+ head.next = (struct cds_hlist_node *) node_flag;
+ return head;
}
/*
struct cds_ja_node *child_node)
{
struct cds_ja_shadow_node *shadow_node = NULL,
- *parent_shadow_node = NULL,
- *iter_shadow_node;
+ *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;
cds_hlist_add_head_rcu(&child_node->list, &head);
iter_node_flag = (struct cds_ja_inode_flag *) head.next;
- /* Create shadow node for the leaf node */
- dbg_printf("leaf shadow node creation\n");
- iter_shadow_node = rcuja_shadow_set(ja->ht,
- ja_node_ptr(iter_node_flag), NULL);
- if (!iter_shadow_node) {
- ret = -ENOMEM;
- goto check_error;
- }
- created_nodes[nr_created_nodes++] = iter_node_flag;
-
for (i = ja->tree_depth; i > (int) level; i--) {
uint8_t iter_key;
}
/*
- * 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.
+ * Lock the parent containing the hlist head pointer, and add node to list of
+ * duplicates. Failure can happen if concurrent update changes the
+ * parent before we get the lock. We return -EAGAIN in that case.
* Return 0 on success, negative error value on failure.
*/
static
int ja_chain_node(struct cds_ja *ja,
+ struct cds_ja_inode_flag *parent_node_flag,
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);
+ ja_node_ptr(parent_node_flag));
if (!shadow_node)
return -EAGAIN;
cds_hlist_add_head_rcu(&node->list, head);
parent2_node_flag, key, i, new_node);
} else {
ret = ja_chain_node(ja,
- (struct cds_hlist_head *) ja_node_ptr(node_flag),
+ parent_node_flag,
+ (struct cds_hlist_head *) node_flag_ptr,
new_node);
}
if (ret == -EAGAIN)
return ret;
}
+/*
+ * Note: there is no need to lookup the pointer address associated with
+ * each node's nth item after taking the lock: it's already been done by
+ * cds_ja_del while holding the rcu read-side lock, and our node rules
+ * ensure that when a match value -> pointer is found in a node, it is
+ * _NEVER_ changed for that node without recompaction, and recompaction
+ * reallocates the node.
+ */
static
int ja_detach_node(struct cds_ja *ja,
struct cds_ja_inode_flag **snapshot,
+ struct cds_ja_inode_flag ***snapshot_ptr,
+ uint8_t *snapshot_n,
int nr_snapshot,
uint64_t key,
struct cds_ja_node *node)
{
- int ret;
+ struct cds_ja_shadow_node *shadow_nodes[JA_MAX_DEPTH];
+ struct cds_ja_inode_flag **node_flag_ptr = NULL,
+ *parent_node_flag = NULL,
+ **parent_node_flag_ptr = NULL;
+ struct cds_ja_inode_flag *iter_node_flag;
+ int ret, i, nr_shadow = 0, nr_clear = 0;
+ uint8_t n;
assert(nr_snapshot == ja->tree_depth - 1);
+ /*
+ * From the last internal level node going up, get the node
+ * lock, check if the node has only one child left. If it is the
+ * case, we continue iterating upward. When we reach a node
+ * which has more that one child left, we lock the parent, and
+ * proceed to the node deletion (removing its children too).
+ */
+ for (i = nr_snapshot - 1; i >= 1; i--) {
+ struct cds_ja_shadow_node *shadow_node;
+
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ ja_node_ptr(snapshot[i]));
+ if (!shadow_node) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ assert(shadow_node->nr_child > 0);
+ shadow_nodes[nr_shadow++] = shadow_node;
+ nr_clear++;
+ if (i == nr_snapshot - 1) {
+ /*
+ * Re-check that last internal node level has
+ * only one child, else trigger a retry.
+ */
+ if (shadow_node->nr_child != 1) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ }
+ if (shadow_node->nr_child > 1 || i == 1) {
+ /* Lock parent and break */
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ ja_node_ptr(snapshot[i - 1]));
+ if (!shadow_node) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ shadow_nodes[nr_shadow++] = shadow_node;
+ node_flag_ptr = snapshot_ptr[i];
+ n = snapshot_n[i];
+ parent_node_flag_ptr = snapshot_ptr[i - 1];
+ parent_node_flag = snapshot[i - 1];
+ if (i > 1) {
+ /*
+ * Lock parent's parent, in case we need
+ * to recompact parent.
+ */
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ ja_node_ptr(snapshot[i - 2]));
+ if (!shadow_node) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ shadow_nodes[nr_shadow++] = shadow_node;
+ }
+ break;
+ }
+ }
+
+ /*
+ * At this point, we want to delete all nodes in shadow_nodes
+ * (except the last one, which is either the root or the parent
+ * of the upmost node with 1 child). OK to as to free lock here,
+ * because RCU read lock is held, and free only performed in
+ * call_rcu.
+ */
+
+ for (i = 0; i < nr_clear; i++) {
+ ret = rcuja_shadow_clear(ja->ht,
+ shadow_nodes[i]->node,
+ shadow_nodes[i],
+ RCUJA_SHADOW_CLEAR_FREE_NODE
+ | RCUJA_SHADOW_CLEAR_FREE_LOCK);
+ assert(!ret);
+ }
+
+ iter_node_flag = parent_node_flag;
+ /* Remove from parent */
+ ret = ja_node_clear_ptr(ja,
+ node_flag_ptr, /* Pointer to location to nullify */
+ &iter_node_flag, /* Old new parent ptr in its parent */
+ shadow_nodes[nr_clear], /* of parent */
+ n);
+
+ /* Update address of parent ptr in its parent */
+ rcu_assign_pointer(*parent_node_flag_ptr, iter_node_flag);
+
+end:
+ for (i = 0; i < nr_shadow; i++)
+ rcuja_shadow_unlock(shadow_nodes[i]);
+ return ret;
+}
+
+static
+int ja_unchain_node(struct cds_ja *ja,
+ struct cds_ja_inode_flag *parent_node_flag,
+ struct cds_ja_node *node)
+{
+ struct cds_ja_shadow_node *shadow_node;
+ int ret = 0;
+
+ shadow_node = rcuja_shadow_lookup_lock(ja->ht,
+ ja_node_ptr(parent_node_flag));
+ if (!shadow_node)
+ return -EAGAIN;
+ /*
+ * Retry if another thread removed all but one of duplicates
+ * since check.
+ */
+ if (shadow_node->nr_child == 1) {
+ ret = -EAGAIN;
+ goto end;
+ }
+ cds_hlist_del_rcu(&node->list);
+end:
+ rcuja_shadow_unlock(shadow_node);
return ret;
}
+/*
+ * Called with RCU read lock held.
+ */
int cds_ja_del(struct cds_ja *ja, uint64_t key,
struct cds_ja_node *node)
{
unsigned int tree_depth, i;
struct cds_ja_inode_flag *snapshot[JA_MAX_DEPTH];
+ struct cds_ja_inode_flag **snapshot_ptr[JA_MAX_DEPTH];
+ uint8_t snapshot_n[JA_MAX_DEPTH];
struct cds_ja_inode_flag *node_flag;
+ struct cds_ja_inode_flag **prev_node_flag_ptr;
int nr_snapshot = 0;
int ret;
key, node);
/* snapshot for level 0 is only for shadow node lookup */
+ snapshot_n[nr_snapshot] = 0;
+ snapshot_ptr[nr_snapshot] = NULL;
snapshot[nr_snapshot++] = (struct cds_ja_inode_flag *) &ja->root;
node_flag = rcu_dereference(ja->root);
+ prev_node_flag_ptr = &ja->root;
/* Iterate on all internal levels */
for (i = 1; i < tree_depth; i++) {
if (!ja_node_ptr(node_flag)) {
return -ENOENT;
}
- snapshot[nr_snapshot++] = node_flag;
iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - i - 1)));
+ if (nr_snapshot <= 1)
+ snapshot_n[nr_snapshot] = 0;
+ else
+ snapshot_n[nr_snapshot - 1] = iter_key;
+
+ snapshot_ptr[nr_snapshot] = prev_node_flag_ptr;
+ snapshot[nr_snapshot++] = node_flag;
node_flag = ja_node_get_nth(node_flag,
- NULL,
+ &prev_node_flag_ptr,
iter_key);
- dbg_printf("cds_ja_del iter key lookup %u finds node_flag %p\n",
- (unsigned int) iter_key, node_flag);
+ dbg_printf("cds_ja_del iter key lookup %u finds node_flag %p, prev_node_flag_ptr %p\n",
+ (unsigned int) iter_key, node_flag,
+ prev_node_flag_ptr);
}
/*
} else {
struct cds_hlist_head *hlist_head;
struct cds_hlist_node *hlist_node;
- struct cds_ja_node *entry;
- int found;
+ struct cds_ja_node *entry, *match = NULL;
+ int count = 0;
hlist_head = (struct cds_hlist_head *) ja_node_ptr(node_flag);
- cds_hlist_for_each_entry(entry,
+ cds_hlist_for_each_entry_rcu(entry,
hlist_node,
hlist_head,
list) {
- if (entry == node) {
- found = 1;
- break;
- }
+ if (entry == node)
+ match = entry;
+ count++;
}
- if (!found)
+ if (!match)
return -ENOENT;
- ret = ja_detach_node(ja, snapshot, nr_snapshot, key, node);
+ assert(count > 0);
+ if (count == 1) {
+ /*
+ * Removing last of duplicates.
+ */
+ snapshot_ptr[nr_snapshot] = prev_node_flag_ptr;
+ snapshot[nr_snapshot++] = node_flag;
+ ret = ja_detach_node(ja, snapshot, snapshot_ptr,
+ snapshot_n, nr_snapshot, key, node);
+ } else {
+ ret = ja_unchain_node(ja, node_flag, entry);
+ }
}
if (ret == -EAGAIN)
goto retry;
projects / userspace-rcu.git / commitdiff
